*Article* **Monitoring Small Water Bodies Using High Spatial and Temporal Resolution Analysis Ready Datasets**

**Vinicius Perin 1,\*, Samapriya Roy 2, Joe Kington 2, Thomas Harris 2, Mirela G. Tulbure 1, Noah Stone 2, Torben Barsballe 2, Michele Reba 3 and Mary A. Yaeger 4**

**Abstract:** Basemap and Planet Fusion—derived from PlanetScope imagery—represent the next generation of analysis ready datasets that minimize the effects of the presence of clouds. These datasets have high spatial (3 m) and temporal (daily) resolution, which provides an unprecedented opportunity to improve the monitoring of on-farm reservoirs (OFRs)—small water bodies that store freshwater and play important role in surface hydrology and global irrigation activities. In this study, we assessed the usefulness of both datasets to monitor sub-weekly surface area changes of 340 OFRs in eastern Arkansas, USA, and we evaluated the datasets main differences when used to monitor OFRs. When comparing the OFRs surface area derived from Basemap and Planet Fusion to an independent validation dataset, both datasets had high agreement (r2 ≥ 0.87), and small uncertainties, with a mean absolute percent error (MAPE) between 7.05% and 10.08%. Pairwise surface area comparisons between the two datasets and the PlanetScope imagery showed that 61% of the OFRs had r2 ≥ 0.55, and 70% of the OFRs had MAPE <5%. In general, both datasets can be employed to monitor OFRs sub-weekly surface area changes, and Basemap had higher surface area variability and was more susceptible to the presence of cloud shadows and haze when compared to Planet Fusion, which had a smoother time series with less variability and fewer abrupt changes throughout the year. The uncertainties in surface area classification decreased as the OFRs increased in size. In addition, the surface area time series can have high variability, depending on the OFR environmental conditions (e.g., presence of vegetation inside the OFR). Our findings suggest that both datasets can be used to monitor OFRs sub-weekly, seasonal, and inter-annual surface area changes; therefore, these datasets can help improve freshwater management by allowing better assessment and management of the OFRs.

**Keywords:** analysis ready datasets; PlanetScope; Basemap; Planet Fusion; on-farm reservoirs; water management


Preface

The emergence of artificial intelligence (AI) is changing the way business processes and customer services are executed in organizations both internally and externally. For example, today, instead of interacting with a human representative, customers are often directed to AI-driven software agents called chatbots, which provide services automatically based on the client's questions. The integration of chatbots in daily business has become a reality and is just the beginning of AI being applied to businesses and many other economic sectors worldwide.

This book presents the latest advances in chatbots and brings to light the latest findings and future research in chatbot architectures. It also explains how chatbots work in different domains, their current technological limitations, and future trends of the technology. The book promotes the creation of interdisciplinary research teams to push the edge of innovation and research of the next generation of AI-driven conversational technologies.

> **Eduard Babulak** National Science Foundation, Alexandria, VA, USA

**1**

**Chapter 1**

*Eduard Babulak*

**1. Introduction**

Introductory Chapter: Journey to

Business communication today is driven by the organizational financial performance and customer best quality service provision. The rise of 24/7 ubiquitous access to Internet and Applied Artificial Intelligence (AAI) creates a platform for future fully-automated cyberspace. Role of Computing has become an essential part of research, innovation and development of future cutting-edge technologies that will transform the way we live to a next level, where Machine-to-Machine Communication

Today we see the technology that has brought the Computational Machines much closer to us people, and LEXA is becoming an integrated part home companionship and the entertainment for many young families who are tech-savvy and love to play with the high-tech. Naturally, there are many dimensions to technological innovation and application of AI that are fascinating and inspire scholars and industry developers to push the edge of advancement of next generation technologies that will

The Machine learning (ML) as a subdomain of artificial intelligence enables smart computational device to abstract patterns from data without explicit programming. In addition to AI and ML, we see the rise of Humanoid Robotics that has potential to act like, look like, talk like and reason like human, and eventually becoming an essential

Some experts compare level of intelligence of new Humanoid Robot called Sophia to that of a one month old new born baby that is at the very beginning of discovering the world around and is beginning to observe and to learn to communicate with his or her parents. Yet, very young and tiny, babies have a Natural Intelligence and Human Reasoning that may be compared to a computational capacity of most performant

Many experts suggest that there are fundamental differences between the AI and Natural Intelligence (NI) and that future evolution of AI driven Software Agents and Humanoid Robotics may have strong impact on the future Industry 5.0 and 6.0, Business to Business (B2B) and Mobile Commerce (mC). Given recent COVID relates crisis, applications of AI in business, industry, government, academia and other sectors have become ubiquitous showing more and more examples of Smart Software

The next section, presents examples of the AI driven applications including

chatbots and ChatGPT, and discus what, how and where they are.

AI Driven Chatbots

will drive Human-to-Human Communication.

Supercomputer in the world today.

Agents application.

promote a Cyber Automation and Ultra Smart Living for everyone.

part of an organizational business infrastructure worldwide [1].


**4.1 Construction and production of SC**

The construction of the laboratory prototype and zero series begins with the choice of material and type of supercapacitor (asymmetrical - polarized, or symmetrical nonpolarized). The variant with a solid active material, which the authors of this chapter have often used, is shown in **Figure 4**. The connection of the active material

*Construction of supercapacitor prototype [23].*

#### **Figure 5.**

with the power supply is achieved by using conductive silver glue. The role of a separator is provided by a Nafion foil soaked in a selected electrolyte.

Today, the active material is applied from a suspension, as well as the printing techniques that are also applied for micro SC (**Figures 5** and **6**).

#### **Figure 6.**

*(a–c) Schematic diagram of the fabrication process for micro-supercapacitors by laser scribing method. (d, e) Flexible micro-supercapacitors with high areal density [25].*

**Figure 7.** *Structure of Murata's supercapacitor (cross-section) [26].*

*Supercapacitors: The Innovation of Energy Storage DOI: http://dx.doi.org/10.5772/intechopen.106705*

#### **Figure 8.** *Supercapacitor engine start module [27].*

After testing and optimization, a zero series is made, where the technological processes of production are elaborated (and often simplified) and only then the mass production could start. The appearance and structure of a commercial supercapacitor of low power and capacitance are shown in **Figure 7**, and for higher powers, voltages, and capacitances, it is shown in **Figure 8**.

Depending on the field of application and the set of parameters, the final structure, production technology, and housing are selected. If the supercapacitor is used as a replacement for a battery to power small consumers, in addition to the capacitance, it is very important that it has a low leakage current. In contrast, when powering larger consumers, it is much more important that the supercapacitor has a low series resistance due to losses at high currents. Thus, the type of supercapacitor is defined. As an example, in **Figure 9**. the types of supercapacitors are given for the different needs of power supply backup.

### **4.2 Modeling and characterization of SC**

In order to predict the behavior in different conditions, electrochemical processes are modeled and simulated on the computer [2]. Most often, an equivalent electric circuit with two or more RC branches is taken as a model (**Figure 10**) [29].

For many years, the authors of this chapter have done research in this area and have developed their models. The simplified model will be presented here for the case of sulfide minerals in an aqueous solution of sulfuric acid. The equivalent circuit, shown in **Figure 11**, was adopted. Capacitors represent double-layer and diffusion capacitance, and resistors correspond to electrolyte resistance, diffusion resistance, and leakage current.

**Figure 9.** *Performance for supercapacitor selection [28].*

#### **Figure 10.**

*EDLC models: A - ideal capacitor, B - series RC model, C - model B with added leakage resistor, D - model C with added high-frequency inductance component, and E - model D expanded with n-branch RC circuits and voltagedependent main capacitance [29].*

*Supercapacitors: The Innovation of Energy Storage DOI: http://dx.doi.org/10.5772/intechopen.106705*

**Figure 11.** *The equivalent electric circuit.*

**Figure 12.** *The circuit excitation and the response.*

For the assumed equivalent electric circuit of the observed electrochemical system and a short voltage pulse (of the order of 0.1 s for such systems), the response of the system (current in this case) will be as shown in **Figure 12**. The following parameters are:

*I* ¼ *E R*0þ*R*123 - quasi-stationary charging current. *R*123 ¼ *R*1*R*2*R*3 *R*1*R*2þ*R*1*R*3þ*R*2*R*3 - eq. resistance of parallel connection R1, R2, and R3. *I*10 ¼ �*UC*10 *R*1þ*R*023 - initial discharge current. *R*023 ¼ *R*0*R*2*R*3 *R*0*R*2þ*R*0*R*3þ*R*2*R*3 - eq. resistance of parallel connection R0 , R2, and R3. *UC*10 ¼ *I*2∙Δ*t C*1 *R*2 *R*1þ*R*2 - initial discharge voltage of capacitor C1. *I*20 ¼ �*UC*20 *R*2þ*R*03 - quasi-stationary discharge current. *R*03 ¼ *R*0*R*3 *R*0þ*R*3 - eq. resistance of parallel connection R0 and R3. *UC*20 ¼ *I*2Δ*t C*2 *R*1 *R*1þ*R*2 - initial discharge voltage of capacitor C2. *τ*1 ¼ ð Þ *R*1 þ *R*023 *C*1 - time constant of the first discharge phase. *τ*2 ¼ ð Þ *R*21 þ *R*03 *C*2 - time constant of the second discharge phase.

Based on the given analysis, the parameters of the electric circuit can be determined, and therefore, in the same manner, the physical parameters of the electrochemical system [30].

In order to check the provided model, an electrochemical system was formed. Several experiments were performed using this method and it has been verified and determined that it can be applied for rapid characterization of electrochemical systems. The experiments were carried out using a system for electrochemical tests based on a PC and the LabVIEW software package (**Figure 13**) [31]. The system is designed to cover most electrochemical tests in wide ranges, both at the level of the electrochemical cell, and at the level of the completed supercapacitor (**Figure 14**) [32].

Modeling can also be done on a physical level. For example, a finite element model for charge transport in conjugated polymers has been developed, but it is still being refined [33].

**Figure 13.** *System for electrochemical testing.*

*Supercapacitors: The Innovation of Energy Storage DOI: http://dx.doi.org/10.5772/intechopen.106705*

**Figure 14.**

*Block diagram of the system for supercapacitor prototype characterization.*

### **5. Use of supercapacitors**

From the user's point of view, the most environmentally friendly form of energy is electricity. However, if we take into account the way in which this energy was obtained, then it fully retains its ecological advantage only if it originates from solar energy, wind, and wave energy, and to a considerable extent, from hydropower. In the latter case, namely, significant harmful ecological effects may occur due to disturbance of water regimes, such as surface waters. However, even when the electricity comes from the burning of fossil fuels or from nuclear reactions, problems related to the negative effects of by-products can be solved much more efficiently in one place than, for example, in all vehicles that move using the appropriate energy. One of the conditions for the use of electric energy in vehicles is the existence of such a device that would have high specific energy but at the same time a high specific power, which standard electric devices could not provide. The advent of supercapacitors has made this application much more realistic.

In the case of supplying consumers with energy that comes from solar or wind energy, it is necessary to have an appropriate method of energy storage for the period when there is no sun or wind. In this case, supercapacitors have an advantage over standard batteries because they can withstand a much greater number of charging and discharging cycles.

From a very large number of possible applications of supercapacitors, current examples will be listed where their characteristics are irreplaceable.

#### **5.1 Energy harvesting**

Monitoring of environmental parameters requires the installation of systems in inaccessible and dangerous terrains. After installation, the system is expected to have a lifetime as long as possible with minimal maintenance. In addition, energy consumption is directly related to the lifetime of a wireless sensor network (WSN). It is similar to other scattered and/or remote systems. Primary (non-rechargeable) batteries, despite the application of modern energy management algorithms, have the greatest impact on the limited lifetime of a wireless sensor node. Also, regular technical interventions in the field, primarily battery replacement, drastically increase the cost of maintenance. With the aim of increasing the life span and reducing maintenance costs, current research studies involve the use of secondary (rechargeable)

**Figure 15.** *Environmental energy sources [35].*

batteries and the so-called collecting energy from the environment, that is, "energy harvesting" (EH), which contributes to WSM getting the self-powered prefix. Due to the characteristics of secondary batteries that degrade over time, the increase in lifetime is insufficient for multi-year monitoring of certain environmental parameters. This is the reason why, instead of rechargeable batteries, capacitors with very large capacities— supercapacitors—can be used to power the node. They represent reversible electrochemical systems, and they are increasingly used to power sensor nodes. For several reasons, supercapacitors are favorable for power supply, one of them being the exceptional scalability that allows increasing capacity and performance with increasing dimensions and weight. The characteristics of supercapacitors, such as high-power density, fast charging, large number of charging cycles, temperature stability, small equivalent series resistance, and low leakage current, favor the operation mode of most wireless sensor nodes. However, the lower energy density compared to batteries contributes to the fact that they are discharged relatively quickly and require frequent recharging. That is why it is necessary to provide a constant or at least intermittent source of energy in the natural environment. It can be a solar panel, piezo vibration transducer, thermoelectric generator, antenna, etc. [34]. Possible sources of environmental energy are shown in **Figure 15**.

#### *5.1.1 Piezoelectric effect*

Piezoelectric materials have the property of converting energy through the direct piezoelectric effect, the energy of mechanical deformations of the piezoelectric structure into the electric field, that is, voltage [36]. Two modes, that is, mode 33 and mode 31, are used in most developed EH applications (**Figure 16**). In both of these modes, the electric field, and thus, the generated voltage on the electrodes, are oriented along the direction of polarization 3, while external forces cause stresses in a single direction. In mode 33, this is the same direction as the stress (3), while in mode 31 the stresses are along the normal (1) [37].

*Supercapacitors: The Innovation of Energy Storage DOI: http://dx.doi.org/10.5772/intechopen.106705*

**Figure 16.** *Operational modes of piezoelectric material for EH applications [37].*

#### *5.1.2 Electromagnetic conversion*

Electromagnetic induction, described by Faraday's law, is the creation of electromotive force (EMF), that is, voltage on an electric conductor in a changing magnetic field, a phenomenon that forms the basis of electric generators. The induced EMF is proportional to the strength of the magnetic field, the speed of the relative movement, and the number of turns of the conductor. If a conductor is connected to an electrical load, the current will flow, thus generating electricity. This system is often used as an effective tool for the realization of kinetic EH systems, where the relative displacement of the permanent magnet in relation to the coil is caused by the vibrations of the energy generation base [38].

#### *5.1.3 Comparison of piezoelectric and EH devices with electromagnetic vibrations*

The results of a thorough comparison of electromagnetic and piezoelectric vibration EH systems, with identical volumes, seismic masses, natural frequencies, quality factors, and excitation conditions, are given in [39]. Appropriate mathematical models of both types of vibration EH devices were used for the calculation of output voltages and powers (**Figure 17**) and depending on the intensity and frequency of harmonic dynamic excitation, the recommended configuration of the most efficient vibration EH systems [39].

#### *5.1.4 Magneto-strictive effect*

Physically in a way similar to the piezoelectric effect. A characteristic property of magneto-strictiveness is that the magneto-elastic coupling induces mechanical

#### **Figure 17.** *Model of electromagnetic (a) and piezoelectric (b) vibration EH systems for output power analysis [39].*

elongations if they are subjected to a magnetic field, while conversely, their magnetization will change due to changes in the applied mechanical stresses. This effect can be used in EH devices, however, an additional coil is required to obtain electrical energy [35].


**3.1 Fear of the unknown**

The adoption of any new farming technology is often received by farmers with a lot of skeptism because of fear of the implications of the new technology on the productivity of their crops. Thus, adoption of such technologies is often slow until when fully convinced of its advantages over the traditional systems. Experience has shown that the transition from conventional agriculture to nature farming or organic farming can involve certain risks, such as initial lower yields and increased pest problems (James, 1994). However, once the transition period is over, which might take several years, most farmers find their new farming systems to be stable, productive, manageable, and profitable. In this case, the use of organic wastes will be beneficial through abundance of beneficial micro-organisms (characteristic of organically amended soils) which can fix atmospheric nitrogen, decompose organic wastes and residues, detoxify pesticides, suppress plant diseases and soil-borne pathogens, enhance nutrient cycling and produce bioactive compounds such as vitamins hormones and enzymes that stimulate plant growth (Higa, 1995). Besides, amendments may increase soil populations of micro-organisms antagonistic to nematodes, but are also known to release several toxic compounds during their decomposition in soil that act directly by poisoning the phyto-parasitic nematodes (Oka and Pivonia, 2002).

### **3.2 Dosage/Application rate**

The quantities of organic wastes usually required per unit area are large.This poses problems of acquisition transportation and application particularly in large scale farms. Fortunately, in Nigeria and other developing countries, these wastes are in abundance. Large quantities of refuse dump sites, rice and other cereal straws, industrial wastes such as saw dust, rice husk, by-products of breweries, agro-processing plants etc abound. Concerted efforts by governments, organizations, non-governmental organizations (NGOs), research centers etc. are needed to mobilize these resources for use either directly or transformed into other products that can be utilized more easily by the farmers. In Taiwan for instance, fertilizers and organic wastes have been transformed into different products that are used to control plant diseases including nematodes (Huang and Huang, 1993; Huang and Kuhlman, 1991; Huang *et al*., 2003).


**7.3 The effects of the shift of the curriculum from old NCS (grade 10: 12) to new CAPS curriculum**

This section discusses the effects of the changes in the coverage of EE/ESD topics from the old NCS (Grade 10–12) to CAPS. It answers the research sub-questions, which is, "*To what extent are environmental education/education for sustainable development topics being covered in teaching and learning documents used by teachers and learners in Geography Grade 12 curriculum?"* This section discusses general and specific results based on the breadth and depth of EE/ESD coverage in both curricula as seen in **Tables 4** and **5**.

#### **Table 5.** *Environmental impact topics and content found in the grade 12 subjects.*

When comparing the content breadth structural differences between old NCS (Grade 10–12) and CAPS were evident. As seen in **Tables 4** and **5** CAPS documents were easier to analyse, where the work schedule showed the topics to be covered and it was easier for the EE/ESD topics to be identified compared to the old NCS (Grade 10–12). However, in Geography there was a notable decrease in the depth of EE/ESD content coverage in CAPS when compared to old NCS (Grade 10–12).

In sum, the overall structural presentation of the content in CAPS was clearer than in old NCS (Grade 10–12). The researcher also realised that in some of the CAPS documents, the description and clearer specification of content to be covered in a particular time make it easier for teachers to follow a specific time frame for the topics to be taught and teachers are exposed to clear EE/ESD topics to be covered during the year. From the analyses, it was revealed that CAPS is pitched at the micro-level, where the teacher is the implementer of a developed programme. This is in contrast with the old NCS (Grade 10–12) where the policy was developed at the macro-level and focused on meeting the LOs and ASs. This implies that CAPS provides more structural Geography content support to both novice and experienced teachers because of its prescriptive nature. From analysis of the two curricula, it appears that CAPS was the ideal policy as it was easier for stakeholders to implement compared to the old NCS (Grade 10–12) in the teaching and learning of EE/ESD topics in Geography.

A second example of the decrease in Geography, wherein old NCS the coverage of EE/ESD topics was in LO 2: The development of knowledge and understanding, and LO 3: The application of knowledge and skills. Firstly, the content involved learners being expected to demonstrate a fundamental knowledge of physical and human processes and the patterns which result from them, as well as the interactions between humans and the environment at local and national scales. Secondly, Geography seeks to understand human-environment interactions. Likewise, the environment and the availability of resources in regions and places shape human activities and lifestyles, and ultimately their well-being. In addition, it is concerned about how people depend on, adapt to, and modify environments, and considers the consequences of human actions. In summary, the Geography content involves learning about climate and weather, fluvial processes and landforms, people and places and needs as seen in **Table 5**. On the other hand, in CAPS only topics such as environmental impacts of

#### **Table 6.**

*Showing coverage of EE/ESD topics in geography examinations.*

#### *Effects of the Changes of Curriculum on the Coverage of Environmental Content in Geography DOI: http://dx.doi.org/10.5772/intechopen.104988*

development and energy management, human-environmental interactions and social impact and environmental quality and quality of life were covered.

Geography had the following EE/ESD topics which were found in the policy documents: impact of climate change, loss of biodiversity, land degradation, drought, river pollution, air pollution, health hazards caused by mines, soil destruction, improper solid waste disposal, poverty, the negative impact of human activities on wildlife, food security, effects of berg winds on veld fires, negative effects of overpopulation in urban areas, water pollution in the Vaal River, environmental impact of cyclones, high levels of pollution in the outskirts of towns, soil erosion and overstocking. The difference in the coverage between old NCS and CAPS in this subject was that old NCS covered Learning Outcome 1 and 2 that taught learners about the development of knowledge and understanding and Learning Outcome 3 which facilitated the application of knowledge and skills. However, CAPS covered these specific topics, understanding climate change and changing weather patterns, sustainable development principles and practices. Furthermore, CAPS covered urbanisation and land use management and sustainability, management of natural resources.

It is evident that the shift of the curriculum from old NCS to CAPS enhanced the coverage of EE/ESD topics in the new CAPS curricula for Geography as shown in **Table 6**.

In Geography, past examination papers from 2006 to 2015 revealed that the following EE/ESD topics were covered: these are the impacts of climate change, loss of biodiversity, land degradation, drought, river pollution and air pollution, health hazards caused by mines, poverty, negative impacts of human activities on wildlife and food security. The following topics were also identified: effects of berg winds on veld fires, negative effects of overpopulation in urban areas, water pollution in the Vaal River, environmental impact of cyclones and high levels of pollution in the outskirts of towns, soil erosion and overstocking. The information on the past examination was sourced from the DBE website http://www.education.gov.za/ in 2022. In Geography, the coverage of environmental impact topics in the past examination papers shows an average of 11% over the ten years under research.

## **7.4 Coverage in the policies and examinations of EE/ESD between RNCS and CAPS**

In Geography was observed that the Old NCS and CAPS policies were **not aligned,** and the reason was that in the old NCS only themes and LOs were written while in the CAPS curriculum only the actual content to be taught was stipulated. The vertical alignment of policy and examination content in old NCS and CAPS revealed that the policies and examination content were aligned. Further analysis revealed that both policies had similar EE/ESD topics such as tropical storms causing floods, climate change, soil degradation, water and air pollution, environmental dangers of berg winds' negative impact on human beings, etc. In addition, old NCS also covered topics such as deforestation, negative impact on urban growth, etc. The shift in the curriculum increased the coverage of EE/ESD topics in the examinations. This contrasts with the results on policies that revealed that the content in old NCS was more than that of CAPS. This is shown in **Table 6**, which reveals extensive coverage of EE/ ESD topics in 2008. It cannot go without notice that in 2012, under CAPS, the breadth of environmental impact topics was the highest when compared to the other years, with 2011 and 2015 recording the lowest percentages in summative assessment. It was also noted that Geography, when compared with the other eleven subjects analysed,

had the widest coverage of environmental impact topics in both the old NCS and CAPS curricula. When comparing the topics, the old NCS had the widest range of environmental impact topics compared to CAPS. Overall, the shift in the curriculum in Geography decreased content coverage in CAPS policy while it increased environmental impact coverage in the actual Grade 12 examinations when compared to the old NCS. The shift from old NCS to CAPS, therefore, improved Geography EE/ESD topics coverage in practice.


*Article* **Supporting School Aged Children to Train Their Vision by Using Serious Games**

**Ilona Heldal \* , Carsten Helgesen, Qasim Ali , Daniel Patel, Atle Birger Geitung and Håvard Pettersen**

Department of Computer Science, Electrical Engineering and Mathematical Sciences, Faculty of Engineering and Science, Western Norway University of Applied Sciences, Inndalsveien 28, 5063 Bergen, Norway<EMAIL_ADDRESS>(C.H<EMAIL_ADDRESS>(Q.A<EMAIL_ADDRESS>(D.P<EMAIL_ADDRESS>(A.B.G<EMAIL_ADDRESS>(H.P.)

**\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** Several children struggle with vision difficulties caused by problematic coordination between their left and right eye muscles, i.e., oculomotor dysfunction (OMD). Many OMDs can be improved by training the eyes via physical exercises defined and supervised by vision experts. The aim of this paper is to investigate the feasibility of utilizing Serious Games (SGs) and eye-tracking technologies (ETs) for training the eyes of children having OMD. Via these activities, a trainee can, with her eye gaze, follow objects which are moving, change their directions and speed, or pop up on the screen. The results present mapping the current physical training goals to activities for SGs using input from ETs, and illustrate this correspondence for designing and developing six games. The games' feasibility evaluation is done via semistructured interviews and evaluating user experiences. Three vision teachers (VTs) were involved in design and development, ensuring achievement of training goals, and five VT students in evaluations. The findings demonstrate the potential of using SGs and ETs to train OMD and point to future needs for improvements.

**Keywords:** OMD; eye-tracking; serious games; training; vision impairment; rehabilitation; vision teachers

#### **1. Introduction**

Vision plays a leading role in our daily activities, influencing our interaction with the outside world. Of all school-aged children, 25–30% have vision problems [1], and many of these were not detected before [2,3]. A child who can clearly see objects at a certain distance can still have a functional vision impairment at other distances [4].

Vision impairments can cause later impediments in academic success, and by this is influencing the education system, public health system, and social well-being [5–7]. A particular part of vision impairments can be corrected by glasses or surgery. A large number of school-aged children (17–30%), such as those having Oculomotor Dysfunctions (OMD), can be helped via vision therapy or training their eyes.Already a few weeks of training can improve their vision [4,8–10]. By school-age children, we mean children who are beginning their school education. OMD hinders automatic control of one's eye muscles for more extended periods than a few seconds, which results in reading or seeing difficulties. Adults also can have OMD, especially after a brain injury [11]. However, they can articulate their problems, while many children are unaware of having OMD and cannot understand its negative influence on their performance [4]. OMD is difficult to detect due to missing resources to screen all school-aged children [4,12]. Since rehabilitation or training takes longer time periods it is even more challenging to support it [13].

In many countries, the last mandatory control of eyes is with a health control at the age of 3–4, while in contrast, their sight is still under development when they begin school [5,14].

**Citation:** Heldal, I.; Helgesen, C.; Ali, Q.; Patel, D.; Geitung, A.B.; Pettersen, H. Supporting School Aged Children to Train Their Vision by Using Serious Games. *Computers* **2021**, *10*, 53. https://doi.org/10.3390/computers 10040053

Academic Editors: Carlos Vaz de Carvalho and Antonio Coelho

Received: 1 March 2021 Accepted: 7 April 2021 Published: 16 April 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

A hypothesis behind this work is that supporting technologies would reduce resources for experts or parents responsible for improving children's vision problems. The first step towards this is investigating how technologies can complement the current physical training of OMD.

While the "end-users" of rehabilitation are children having OMD, the enablers for training and using these technologies as new and complementing methodologies for traditional training are the professionals suggesting and often supervising training. This work focuses on these professionals, the special educators, which are also called vision teachers (VTs). VTs are responsible for children's vision impairments and understanding teaching and education activities [13].

The aim of this paper is to illustrate how serious games (SG) and eye-tracking technologies (ETs) can complement vision training for children with OMD from the perspective of vision teachers (VTs). This is done by describing current training, identifying possible SG support, and testing the feasibility of SGs by VT students. There have been three VTs involved in developing games and five VT students in evaluations. The methodology is inspired by Grounded Design methodology [15], ending with a feasibility study of six SG prototypes based on data from semistructured interviews and user experience evaluation [16,17].

One of the main challenges of this work has been to work interdisciplinary and translate the physical guidelines the VTs identified to improve OMD in children via vision training to guidelines needed for developing games. Another challenge has been to systematically compare the visual stimuli on the computer screen with the physical eye exercises. This paper defines and evalautes the suggested prototypes and describes challenges for further development.

The limitation of this study is in evaluations with end-users. To carry out experiments in children and test the progress and outcomes of using this type of training needs to be done in the next step. However, this step cannot be conducted before investigating the usefulness of the games with vision experts. This paper focuses on VTs as a main stakeholder group, enabling vision training in children.

The structure of this paper is the following. After presenting the literature background (Section 2), we describe the study design via applied methods and materials (Section 3). This is followed by the results (Section 4) in three subsections—the first presents the activities needed to be done during physical vision training. The next examines how these activities can be mapped and triggered with playing SGs. The last subsection contains feasibility evaluation of the suggested SG prototypes by the VTs. The last Sections are the Discussion and future work (Section 5) and Conclusions (Section 6).

#### **2. Literature Background**

#### *2.1. OMD as a Vision Impairment That Can Be Supported with Vision Training*

Good vision is vital for cognitive, physical, and social progress during early childhood and into later years. Many vision problems can be corrected by eyeglasses [18], contact lenses, or laser refractive techniques [18,19], and many, often the functional eye motoric problems, can be improved by training [4].

A significant number of children (17–30%) with OMD have normal vision acuity (sharp vision), but insufficient eye motoric abilities [4]. OMD is associated with problems in coordinating the movements of the eyes (mainly measured via fixation, saccade, and smooth pursuit). A fixation is an ability to pause the eye movement on a particular region for gathering visual information [21]. A saccade is a rapid change of fixation to another fixation [22]. Smooth pursuit occurs when an eye tracks a moving object [23]. A person having anomalies in any of these three eye movements can be diagnosed with OMD. OMD may lead to difficulty to read, difficulty to write, eye fatigue, headache, poor development in eye-hand coordination, or eye fixation loss [9,24]. Children with learning disabilities often have vision problems related to OMD [21,22], and many of them can be helped by timely access to quality eye care [25].

There are several vision experts who provide screening (identification) or treatments (rehabilitation) of eye problems [26]. These are vision specialists, such as ophthalmologists, optometrists, orthoptists and dispensing opticians, often focusing on different parts of the eyes. Many of them, e.g., ophthalmologists, don't necessarily understand how important the children's visual function is, e.g., vision balance or eye accommodation [27]. If an ophthalmologist sees "vision screening," they mainly think about eye diseases, identifying problems that can be corrected via prescriptions of medicine, eyeglasses, or contact lenses. The focus in this paper is vision screening focusing on identifying functional eye problems and vision training for improving these. In Norway and in many other countries the special educators with competence in vision, the vision teachers (VTs), are the main responsible for identifying such problems.

For OMD problems, VTs guide rehabilitation, which includes usually more than three weeks. To support these activities may involve other, often nonprofessional stakeholders, e.g., school teachers or parents. While the effect of vision training in general has been highly debated for several decades [28], there is evidence for the positive effects of vision training [29]. Research and practical studies tested the impact of training the eye-muscles in children with OMD, and found significant improvements in reading skills and decreased duration of unnecessary gaze fixations already after three weeks of regular training [30–33]. The length of the training varies, depending on who defined it the type of the OMD problem and the child. As there is no consensus about an exact test battery for vision screening identifying OMD, there is no consensus for a vision training method. Usually, several exercises are recurring in the different batteries.

Vision training batteries are developed by VTs and include exercises where the children need to move their eyes or focus on particular objects in the surrounding environment. These exercises can be as simple as following a pen back and forth, from left to right or up and down, or more complex, e.g., throwing a ball back and forth, working with puzzles, drawing through a maze using a pencil, jumping around on one leg or finding matching items in a pile [34]. Some of the exercises involve books, and others involve working with paper figures (see Figure 1). Some of the exercises require the participant to sit still, while others encourage full-body movement. Especially at the start many of the activities need help from an expert, being either a VT, or a vision therapist, but later may be complemented or replaced by the assistance from educated teachers or parents in the children's network. There is often a need for creating an individual training program and a personalized set of exercises depending on the diagnosed problem. Depending on the progress the training may also be changed by the experts.

Expertise and planning is needed to design these exercises and make them attractive to children. Therefore, to define adequate training, creativity is an essential aspect VTs need to posses, besides having deep insight into vision problems. Motivating young children to perform repeated activities several times is not easy. Additionally, a VT needs to develop ideas for exercises to fit the individual's specific needs.Ensuring that movements are correctly performed, the VTs can use anaglyphs, lenses, septa, stereoscopes, computer programs, paper, pencil, and miscellaneous tasks in the office and home vision training sessions [35].

Many of the VTs do not have experience in using ET technologies today. Those who are familiar with computerized solutions are using e.g., using *Visagraph* (https: //www.readingplus.com/visagraph/ (accessed on 14 April 2021)) and *ReadAlyzer* (Information of the recently improved ReadAlyzer 2K can be seen at https://www.compevo.se/ (accessed on 14 April 2021)) reading assessment kits for the vision assessment [36]. While considerable attention is on developing technologies supporting reading in general (see Figure 2a,b), the focus of this study is not on reading proficiency, but on connecting eye problems to several problems, such as reading.

**Figure 1.** An exercise requiring papers (the child holds it) and pictures (in the hand of a VT) to examine distance eye dominance.

#### *2.2. The Role of Eye-Trackers in Vision Screening and Training*

One method for studying eye movements is to track the point a user is looking at with ET technology (see Figure 2c). ETs are mainly used to determine the focus of visual attention on the screen or in the environment. An ET records the gaze position while the eyes are looking at a stimulus in real-time [35]. There are numerous ET applications used in research, many in marketing or evaluating the usability of interfaces [37–39].

ET technology has been a successful research tool used in the clinical settings for the diagnosis of patients in psychology, neurology, and ophthalmology [40]. It is widely used in clinical applications for diagnostic and screening purposes or to detect various disorders and home-based rehabilitative treatments [41]. Graphical representations on a screen can both be attention catching and can be followed by subjects who cannot read. Therefore, combining the use of ETs and graphical images with for instance SGs can be considered helpful methods to examine eye problems in youngsters [36,42].

In order to support screening OMD vision impairments, ETs need to be able to register the movements from the left and right eyes separately and correctly and examine these together with information from the environment. The environment is needed for references, e.g., knowing what one is looking at and for how long time, is important to determine visual attention. Figure 2 illustrates some conventional, instrumental, and software-based vision screening tools.

There are efforts to make ETs small and affordable devices for this; at the present stage, there are no commercially available small devices, e.g., mobile phones or tablets, which can be calibrated well [45] or which can measure the left and the right eye movements separately. Similarly, algorithms for handling ET with good enough accuracy for measuring eye movements in immersive environments, e.g., for using HMDs, are complex [46]. Additionally, HMDs with good enough ETs are quite expensive. Therefore, rehabilitation exercises utilizing the entire space need to be improved for better supporting vision training. Todays' vision training is based on exercises using the surrounding space, with possibilities to be complemented by computer-supported exercises. The exercises are seldom connected directly to measuring eye movements. One of the overall goals of this study is to design and develop such exercises, i.e., to automatically follow and measure a child's eye movements when she is training her eyes.

**Figure 2.** Different tools and software programs supporting vision screening: (**a**) Snellen chart [43] used for traditional vision screening; (**b**) Ezer (http://usophthalmic.com/Ezer-ERK-9100 -Autorefractor-Keratometer (accessed on 14 April 2021)) autorefractor is an instrumental device used for measuring refractive error; (**c**) C&Look [44] is an ET based computer software for screening OMD.

ETs can detect and record eye movements following the point of gaze continuously. Figure 3 illustrates a picture from a video recording of a child following a frog via an ET and her left (blue) and right (red) eye gaze on the screen. Having the video recording and the eye positions from an ET, one can measure and visualize coordination problems between the left and right eyes. The background is divided into nine zones. The green color indicates that the child who screens her eyes has a good vision in the respective zones on the screen. The colors of the zones can vary from darker green, lighter green, darker yellow, lighter yellow, lighter red, and red. Depending on the un-correlation between the eye movements, the colors indicate the severity of the observed eye problems.

**Figure 3.** The video follows the frog's graphical representation on the screen superimposed by the representation of the eye gaze from the left and right eyes. The movement of the frog was from up to down (and from left to right). The two lines in the bottom show (problems with) smooth pursuit movements after 11–12 s.

Creating an associated program that can be used after the test to see the eye movements by visualizing these during the performance gives an opportunity to detect eye misalignment. Such programs are e.g., RightEyes program [47] or C&Look [48]. Figure 4 illustrates how the left and right eyes diverge for a child with OMD for saccadic problems in a left eye, during a given time. The left eye movement is visualized with the blue line and the right with the red line. The horizontal eye movements are visualized by the lines on the upper part and vertical movements on the lower part of Figure 4.

**Figure 4.** ET-based OMD examination program (via C&Look [48]) showing saccadic movements with left eye (vibrating) problems. The green line illustrates the "normal" area.

This work builds on the C&Look software for identifying (but not training) OMD problems [44,49]. The C&Look software uses visual tasks to stimulate the eyes of the participants and records their eye trace via an ET. The tracker records multiple metrics such as the Point of Gaze (POG), meaning the point on the screen where the participants' eyes are directed, fixations, saccades, and smooth pursuit. This data is then visualized by using plots so that the discrepancy between the left and right eyes can be examined and quantified, as is shown for saccadic vision problems in Figure 4.

The idea for this C&Look is based on the idea from an earlier, MS-DOS-based nonportable technology developed in the 1980s in Sweden. This MS-DOS-based technology is still in use by the center for special education in Oslo, Norway. C&Look was found equally good to recognize OMD problems as solutions using more expensive ETs by several classes of children [50] and the cheaper version is used in follow up studies in Norway and Tanzania.

#### *2.3. Serious Games and Other Technologies Supporting Vision Problems*

Several training software based on Serious Games (SG) offer improvements with increased motivation and high user experiences, especially for younger children [51]. Digitizing and gamifying the training and learning has several advantages: it makes it more motivating to perform exercises [52,53] which focus on learning basic, often boring things, e.g., methods in engineering [54], or allowing repeated training for increasing skills and competencies in handling emergency cases [55–57].

SG is used on several platforms and often incorporates new technologies. Examples are: using mobile technologies to allow learning outside of a classroom [53], ETs to steer and react to eye movements [13,36], hand-tracking to respond to hand gestures [58], or allowing more immersive experiences, e.g., via head-mounted displays [59] or augmented reality [60]. By recording and examining each movement, one can measure the progress in these games, often automatically and immediately.

SGs can support not only the identification or screening of eye problems, but also training.Current rehabilitation can be boring, due to the requirements to repeat simple movements many times. SGs are used for supporting children's vision training, especially for reading, e.g., via Lexplore [61]. Irazoka and his colleagues present a number of SG tools supporting mild cognitive impairments [62]. This review includes CogPack (http: //markersoftware.com/USA/frames.htm (accessed on 15 April 2021)), a computer-based application supporting training, which influenced the programs developed in this study. It incorporates a large number of games, and according to our knowledge, this was one of the first games for vision training, developed in 1986 and still in use.

Other SG-based programs influencing this study are VisionBuilder (https://visionbuilder. com/login/ (accessed on 15 April 2021)), and ReadAlizer (https://www.compevo.se/ (accessed on 15 April 2021)). With VisionBuilder, a user can train saccades, recognition, word reading, stereo vision (with red/blue glasses), mainly to improve reading. ReadAlizer allows measuring reading progress and also promises to help reading. These methods and tools were also developed by including vision experts but are not directly connected to recognizing and treating OMD problems.

Recently, there are some new ET-based solutions available in the market for vision screening or vision therapy e.g., RightEye (https://righteye.com/ (accessed on 15 April 2021)), Clinical eye tracker by Thomson Software Solutions (https://www.thomsonsoftware-solutions.com/clinical-eye-tracker/ (accessed on 15 April 2021)), or Vivid Vision (https://www.seevividly.com/ (accessed on 15 April 2021)). These are expensive solutions for commercial purposes, mainly for clinicians. Vision therapists often use the Computer Orthoptics liquid crystal system to train for vergence, oculomotor skills, and accommodative eye movements [63]. However, this system is an office-based-solution that must be used under the supervision of vision therapists.

#### **3. Study Design**

#### *3.1. Methodology*

Developing a new and innovative artifact incorporating a number of SGs used for health purposes needs a number of quantitative and qualitative approaches [64]. For this study, the qualitative methods are inspired by the Grounded Design approach defined by Rohde and his colleagues [15], having its roots in Participatory Design [65] and Action Research [66,67]. Grounded Design is applied in case studies for reconstructing "social practices observed before and during the design and appropriation of innovative IT artifacts" (p. 163, [15]). The quantitative method is by adopting the user experience evaluation questionnaire (UEQ) from Schrepp et al. [16].

To design and develop supportive technologies facilitating change processes, i.e., from physical training to SG supported training, involves VTs and computer scientists. Understanding the current situations, suggesting changes, and testing these requires interdisciplinary work. According to the Grounded Design traditions, we consider three important steps:

The first two steps are based on data from participatory observation during several meetings. Data in the last step are coming from interviews and usability evaluation.

Step 1 was performed during a number of meetings between three VTs and five computer scientists and identified the main eye-movements needed to be trained for OMD problems and discussed if and how SGs could support eye movement for training. For this, the suitability of some earlier games and new existing games were also examined (see Section 4.1).

Step 2 included meetings identifying and improving the six games chosen to support training through four iterations and involved the same three VTs and computer scientists. Each iteration was evaluated by at least one of the three VTs and five computer graphics and games experts. The computer experts involved had earlier experiences from developing the ET-based program, *C&Look* for vision screening [48].

Step 3 presented the evaluation of the final prototype. The results came from a Background Questionnaire (BQ), and user experience questionnaire (UEQ) from [16], and was used to measure user acceptance (data from semistructured interviews). Data came from five VT MSc students in Special Education, with earlier experience in teaching and also in screening and training OMD from their current education (see Section 4.3). The data was collected right after the VT students supported 30 children's vision training, a three-week long training period, without computer-supported training. All the VT students tested the games with technical assistance from a computer scientist (who also participated in Step 1 and Step 2).

The three VTs contributing to finding or designing and developing the games were VTs with several years of experience in their professional area, including using ETs in Norway. The five VT students evaluating the games for training were MSc students in Special Education from Tanzania. Only one of these five students had used ET technology before the evaluation of the games. They filled in the BQ and UEQ by themselves and answered the semistructured interview with questions and discussions about the games' applicability and possible improvements. All participants were female and aged between 30–55.

#### *3.2. Materials*

Most of the technologies supporting vision training today are not easily portable, affordable or accessible for children. To keep the prototype portable, the hardware used in the development and testing of this system was a Lenovo Thinkpad T460S Ultrabook™ with a 2.40 GHz Intel Core™ i5 processor, 16 GB of RAM, and a 14-inch multitouch widescreen.

The ET was an EyeX (http://tobiigaming.com/product/tobii-eyex/ (accessed on 15 April 2021)) with a sampling rate of 60 Hz developed by Tobii (https://www.tobii.com/ (accessed on 15 April 2021)), a low-cost commercially available ET (that costs approximately 250 \$) that can be used with most commercial laptops. Examples of similar products currently available are laptops with integrated eye-tracking from Acer, Dell, or MSI.

The games were developed in the Unity (https://unity.com/ (much is based on http: //response.unity3d.com/games-by-the-numbers-q2-2016-report, accessed on 15 April 2021)) game engine using the programming language C#, and applying the EyeX and the C# "Gaze API" provided by Tobii. Unity also features out-of-the-box physics, making it easy to create 2D or 3D objects that act naturally in the applied environment. Since the OMD training application consists of several small games, there is essentially one application for each game connected through Unity's scene management, allowing the user to transition between games smoothly.

 This calibration was implemented in the application through the Gaze API. A user calibrated her eyes by looking at three points for 2 s, one after the other. After a point disappeared, the calibration was performed for that specific area. The calibration time lasted a few minutes (3–5 min). The interaction with the games was performed using eye gaze and pushing some keys on the keyboard.

#### **4. Results**

#### *4.1. How Can Children with OMD Train Their Eyes Eoday? (Step 1)*

There is no generally accepted set of guidelines supporting training programs for children who struggle with OMD.

The most commonly recognized eye motoric challenges (also described in Section 2), the activities they trigger and the physical exercises needed to perform the challenge are described in Table 1, which was built on the suggestion from a vision teacher included in our group [34]. The first three columns in the table illustrate the identified important movements the trainee needs to perform with her eyes to strengthen her visual abilities.The exercises seen in Table 1 are all broad in the sense that one can train more than just one specific ocular muscle movement with each exercise. For example, practicing "Searching/scanning" may train both fixations, endurance, saccades, and mini saccades, depending on how the exercise is performed. Since elements in the vision system are interconnected, one challenge has multiple terms connected to it and several exercises. However, it is necessary to be aware of the fact that children can be stressed and exhausted, and a trainee can also be overloaded if this is done without professional competence.

Visual efficiency disorders are classified into accommodative disorders, binocular vision disorders, amblyopia, and ocular motility disorders [68]. Ocular motility disorders are problems with eye movements such as fixations, saccades, and smooth pursuit [69]. After this identification, the primary mission was to choose games that systematically trigger eye movements to perform exercises needed to support the ocular motor activities from Table 1.

**Table 1.** Training of eye motoric challenges by activities with different exercises.

Since "Field of vision" and "Visual acuity" are broad fields, different games were required to complement each other to cover all movements which need to be performed during the training.

Stereopsis was not a priority in this game because it is hard to simulate animations that could complement accommodations or convergence eye movements on a computer screen. This could be addressed in a future version using an HMD device with integrated eye and hand tracking.

#### *4.2. Finding, Designing, Developing, and Adjusting Games (Step 2)*

#### 4.2.1. Earlier Programs Influencing This Study

Several existing games were investigated to design games for the required exercises (see column 3 from Table 1). These were, first of all, games available from Tobii, or VisionBuilder (mentioned earlier). Cocos2D (http://cocos2d.org/ (accessed on 15 April 2021)) was also considered for this project. However, the code was considered out of date and therefore hard to maintain and develop further. The main problem with Cocos2D was its lack of information about integrating other softwares, and the fact that it had a less comprehensive graphical workflow can make the development process slower. While Tobii provides a low-level C++ SDK that was easier used with Tobii's ET, this was chosen for this project. The games available and possible from Cocos2D but without ET support were also considered more advanced than necessary for this project, having the baseline the games from CogPack.

As we pointed out earlier, there are some existing computer-based applications supporting training. The games that most influenced the development are within the package of 64 games offered by CoGPack. Examining these existing games and having the requirements for exercises presented in Table 1, the VTs identified some more needs the new games should satisfy for covering OMD problems of different severities:

During the four iterations of development, several other properties of the graphical interfaces were discussed with designers and vision teachers. Examples are:

• the possibility to use on-screen documents

Younger children who cannot read can be screened and trained by using graphical images and adjusting its sizes to fit individual problems. These requirements are coming from lessons from experiences from an earlier version of ReadAlizer that could only be used for children who could read texts. The VTs believed in using more graphics, except 3D graphics, at this stage. Several of the identified properties were implemented during the development. After examining additional games, including the ones available through the eye-tracker providers, and CogPack six games (presented in the next Section) were chosen for this study.

#### 4.2.2. Games Triggering Desired Eye Movements

The games were designed and improved based on Table 1 to cover most of the necessary ocular motor activities. Improvement on game design, such as adjusting representations, speed, colors, levels and time to play, were done through four iterations. The software and graphics were improved based on the VTs' experiences regarding images, colors, and movements. First of all, these requirements were adjusted to fit a child's capabilities with a medium-level OMD problem, which is not necessarily an observable vision impairment. These improvements were made during four meetings with programmers and VTs.

The reason for adjusting the settings in each game, e.g., the size, colors, and type of the letters, objects sizes, their spedd and visibility on the screen, number of focus points, was to connect the game difficulty level to the children's capability and considering her vision imediments. The levels must fit each child's problem and it must be possible to adjust the difficulty in games as children learn, or as their vision capabilities improve. Before evaluating the functional prototypes, the three VTs mapped the games' challenges and activities to the challenges identified for physical training described in the first and second columns of Table 1.

#### 4.2.3. The Games

#### *Game 1: Compare Words*

In this game, the user has to look at two similar words and find (and mark) if these words are identical or different. It is inspired by one of the games in CogPack. To identify differences, the user must perform saccades between the words and micro-saccades while studying the single words. The exercise trains both reading, big saccades, and the brain's ability to identify the content. The games can be adjusted with respect to the difficulty of the words, the letter sizes, colors, the language, and the game duration. The number of correct choices for recognizing the same and different words can be seen in the left corner (see Figure 5a).

#### *Game 2: Maze*

The second game's goal is to allow the user to navigate through a maze back and forth with her own gaze without hitting the maze walls (see Figure 5b). After every successful navigation, the user earns one point. The educators could spot the difference in gaze position between the right and the left eyes during the game. This game trains the smooth pursuit, i.e., the ability to follow a path with the gaze and keeps the attention on the road while avoiding obstacles.

**Figure 5.** Screenshots from the games: (**a**) Compare words, with the number of correct choices in the top left corner; (**b**) Maze; (**c**) Save the rocket; (**d**) Find the outstanding object; (**e**) Follow the ball; (**f**) Which one is missing?

#### *Game 3: Save the Rocket*

In this game, a user needs to save a rocket located in the center of the screen from meteors (see Figure 5c). The meteors fly in from the edge of the screen and are eliminated by fixing the gaze at it. If any meteor hits the rocket before the time runs out, the user has failed. The supervisor can set the difficulty level by adjusting the game duration, the number of meteors, and their speed. This game is chosen for training visual attention and continuous performance of saccades.

#### *Game 4: Find the Outstanding Object*

The fourth game includes several objects on the screen, and one of them is different from the others (see Figure 5d). The goal is to find this object and fix the gaze at it for a couple of seconds. This game is much like the game Where is Waldo, with ET input. In this game, it is possible to change the difficulty level by changing the number of distractor objects. It is also possible to choose the types of figures that are shown. The game counts how many seconds the user needed to find the object. Like the game from Figure 5c, this game also trains visual attention. The difference is that the stress level of the environment can be varied by the number of distractions, and also by giving the user more or less time to think and process all the presented objects. The user must continuously perform saccades to move their gaze between the objects, and fixations for analyzing a specific one. Besides, the user needs to utilize the peripheral vision to find interesting areas to look towards.

#### *Game 5: Follow the Ball*

In this game, the user needs to follow a ball that moves smoothly across the screen (see Figure 5e). When the user's gaze is pointed at the object, the score increases. Distractions appear at random places on the screen, but the user should ignore that and keep looking at the chosen moving object. This game runs until a defined number of points is gained. It trains smooth pursuit movement and the ability to control the fixation during distractions.

#### *Game 6: Which One is Missing?*

The last game is a memory game where the user looks at several objects in the first screen. In the next screen, one of theobjects is missing. Then the user must find and pick with their gaze the extra object in the second screen (see Figure 5f for a first screen). When the missing object is found, the user must move it onto a square using their gaze, and press the space button to release it. If this object was the correct one, the level is completed. This game trains visual memory, visual attention, and saccades. When the user is looking at the various objects, the eyes are continually performing saccades.

#### 4.2.4. Connecting the Games to Necessary Eye Movements

Figure 5 presents the last iteration (for a typical screenshot) of the games. They were chosen from a large number of games [70] fulfilling these criteria: suitable for training, possible to use them on portable devices (laptops), suitable for use by affordable eye trackers.. The main criterion was that they would be suitable for training for OMD children.

Table 2 includes the rationale behind the games via the correspondence between Column 2 (what has to be trained) and Column 3 (via which eye movements), and Column 4 (what are the games triggering these eye movements). These correspondences were discussed and games were selected during several meetings with the three VTs involved in the design during a 3–4 month long period, approximately for 1–2 h long meetings with at least one VT involved per week.

**Table 2.** Training of eye motoric challenges by activities with different exercises. The last column (Game) is for Step 2, synthetizing the opinions of VTs, e.g., which games are complementing the challenge and ocular motor activities. See game numbering in Figure 5.

#### *4.3. Evaluating the Feasibility of SG Prototypes for Vision Training (Step 3)*

#### 4.3.1. Results from the User Experience Questionnaire (UEQ)

Table 3 presents the UEQ, with in total 25 aspects to rate. These are examining different aspects of the game ranked from 1 to 7 based on their experience, where 1 was the lowest (most negative), and 7 was the best (most positive) [17]. The respondents were told to put a cross in the circle that represented their answer.

The questions are grouped in three groups and evaluated via four questions for each property:

	- via enjoyable, good, pleasing, pleasant, attractive, and friendly.
	- via stimulation, valuable, exiting, interesting, motivating,
	- via novelty, creative, inventive, leading-edge, innovative.
	- via efficiency, fast, efficient, practical, organized,
	- via perspicuity, understandable, easy to learn, easy, clear,
	- via dependability, predictable, supportive, secure, meets expectations.

The results mirror some of the actual situations, i.e., that the attractiveness of the games is appreciated. While the innovativeness or certain design aspects are not appreciated equally high, the use quality is recognized.

It is challenging to run statistics based on only five participants, so responses have to be treated carefully.

**Table 3.** Answers for the UEQ for all games. The evaluation is done after playing the games.

#### 4.3.2. Answers after Semistructured Interviews

The VT students' first impressions of the games were positive. Answering the question if they would like to use it in their daily work, all, except one, answered yes. The motivation for the "no" was that the game is "*not self-instructing today*." Those who wish to use it also expressed their wishes to have time to find out more about how the games complement the training.

#### Opinions on Using Games to Support Vision Training

Answering the question "What would make use of games more supportive", two VTs expressed their wish "*to have some instructions from the beginning, both for the trainee and the instructor.*"

Discussing opinions for trainees versus instructors, the VTs expressed that the games are "*good for the kids, and they can better understand them* [than instructions for physical exercises, in general]."

One expressed her wish to be able to better adjust the levels in the games to the participants, their age, preferences, and vision impairment. Some games were quite hard to follow, even for those with not severe OMD (Game 2, the Maze, and Game 6, Which one is missing).

VTs expressed their wish to better understand games and their concrete benefit for OMD training. They wished to have some categorization or interface helping the teachers choose and adjust the right games for the expected treatment. An example of this was Game 5 (Follow the ball), as one of the participants noted: "[While this would be a] *good exercise for smooth pursuit movement, it is not completely clear. Maybe you can make different levels of difficulty with different speeds and sizes or colors of the ball? Unsure about the usefulness of the appearing person. Is it actually for concentration or the vision* [attention]?"

#### General Usability

The participants estimated all games as usable in relation to the general usability of objects on the screen (information placement, sizes, colors, etc.). Still, they suggested improvements, especially for Game 2 (the Maze).

They commented on the colors, the speed, and the way that one can progress in the games. For representing the results on the screen, i.e., for Game 3 "Save the rocket", they believed the number illustrating the scores takes too much attention. Perhaps a number showing the time spent with the game might be useful.

Only one of the VT students thought that training with ET-based games could replace physical vision training today, but all participants believe that games have an important place in training and rehabilitation and have a great potential to complement VTs work. The special pedagogy education they follow does not include computer courses, but they think they would manage to handle the games after an easy setup. They do not express any doubts that trainees can learn the games easily, but they could not imagine, at the present state, how trainees could use it by themselves at the beginning.

The VTs like games without many objects on the screen, and they wished to have more contrast. As a VT student expressed, "*For me, it was too low contrasts, even with the calibration dots in the beginning. These should also be bigger*."

Concerning the screen size (playing the games on laptop computers), they believe that a larger screen can allow much more training. However, they also wished to have such supporting games on mobile phones in the future.

#### Overall Experiences of Possible Use and Improvements of the Game

Game 1 (Word differences) was quite outdated, similar to one of the games from Cog-Pack, but "*a good exercise for left-right saccades and fast reading*." Some further development suggestions were to make the game run for x words instead of x seconds and count seconds instead. This would be a better way to track progress. It should also be possible to choose the words' background and position to cover up-down and diagonal saccades.

Game 2 (Maze) was too hard and should be made much easier by making the walls shorter with a longer distance. Apart from that, the game is a good way of training to navigate the eyes through a road avoiding obstacles. One feature that was discussed in this game was initially a bug; when one eye is closed, the user could use the other eye to push the ball through the maze. This could have been a fun element and a new challenge to implement. In this game, it would be good that the VT could see the position of the user's eyes at all times. This may also contribute to the detection of problems during the training.

Game 3 (Save the rocket) This game is very similar to another CogPack game where the user should eliminate incoming shots in a box. The new thing here is that this game features ET and has better graphics. One way of improving this game could be to give a different amount of points per exploding meteor according to how far away from the rocket the meteor is. This would encourage more "searching" and less waiting in the middle. The game could also feature different types of elements instead of only a rocket and meteors, or the contrasts could vary. Apart from that, the game is considered supportive for training saccades and for visual attention by forcing the user to search around the screen. Another suggested improvement regarding these games was to apply a touch screen, where the user had to touch the meteors to eliminate them and examine eye-hand coordination.

Game 4 (Find the outstanding object) could be a replacement for different types of books used in training today. It is very straightforward and fits people of all ages. The game trains saccades between objects as intended, both left-right, up-down, and diagonal. For improvement, it would be nice to be able to choose where in the screen the objects should appear, the spread, and adjust the levels for possible improvements.

Game 5 (Follow the ball) should have more settings. One way is for instance to remove the distraction for the easy levels and maybe add more distractions for the harder levels. One could also vary the size of the ball according to the level of difficulty. The ball could also have a more defined movement. Instead of the current solution, the progress could be measured by the number of points achieved during a limited time. Apart from this, the game is good training for smooth pursuit movements.

Game 6 (Which one is missing?) This game was experienced as too difficult because many objects need to be remembered. It should be possible to choose the level of difficulty and maybe have increasing difficulty for each round. In this game, the space bar is used to pick up items. Maybe blinking to pick up objects can contribute to another layer of difficulty? The game is good training for visual memory and saccades and could be used in training.

#### Overall Experiences of the Games

The VT students were enthusiastic, liked the games, and stated that they were better than existing computerized solutions, but that at the present stage, they cannot fully replace expert-assisted physical training. The main reasons are the limited size of computer screens for peripheral vision training and the lack of possibilities to support depth-training. This was true for all the games. Another reason is the missing overview to see the effect of the training effect, or exactly what is happening during a game, e.g., the visual information on the screen and the eye movements associated with some measures about the movements. Two of the VT students noted that it would be interesting to look at different methods to make the game experience even more enjoyable as some of the exercises were somewhat monotonous.

#### **5. Discussion and Future Work**

Vision training, as most training for rehabilitation purposes, takes time. With a large number of trainees, which there are according to the statistics [3,27], it would be essential if a part of this training could be performed without using more expert resources than necessary. However, it is a long way ahead to substantial digitally assisted training, and expert participation is still critical. There are also hypotheses that schools and general teachers could help and take a more significant role in such training [4,12,13]. At the present moment, the VTs role is also essential. They need to determine the training process and design improvement goals; however, it is not necessarily that they need to support the entire rehabilitation process.

This study investigated the feasibility of SG prototypes. On the way to develop a working product, several aspects can be considered, but probably the most important is to define enablers for utilizing the technologies. In the following parts it is discussed how this can be possible in a more general term.

#### *5.1. Understanding the Whole Process via Interventions and Rehabilitation*

Today screening and training are separate activities, which may be connected to enable children-centric vision care. For helping children with OMD problems many of the actors involved in screening and training are the same, but there are also separate actors, and they should know about the data that are related to the whole process. Ultimately, it would be valuable to contribute to creating tools that foster more children-centric vision care, where much of the training activities could be performed at home, and e.g., progress could be followed by experts.

Screening may also benefit from game-based methods, as this activity is often perceived as boring for children in clinical settings [46], and some children find it hard to sit still during screening. If the screening process could be made more interesting by applying more game elements, this could improve data quality and make screening more accessible. The software also needs to be further developed to better illustrate the connections between exercises, the functional vision, and the effect of training.

#### *5.2. Supporting Technologies: Understand What to Complement and How*

The sensemaking process (*Step 1* and *Step 2* for understanding rehabilitation goals and methods and technologies) is crucial for knowledgeable vision experts to understand technologies' possibilities and define basic requirements for developing technologies. The cooperation with the vision expertise during the development of the game was highly appreciated. Eventually, this shared understanding can be supported by process steering instruments, e.g., Design Thinking.

As we pointed out earlier, a critical aspect is to investigate to what extent game-based training can complement the current training methods. Since depth vision in games is not possible at the present stage, and peripheral vision is limited in the present games, these training exercises have to be supported by physical exercises. With the development of immersive technologies and applications, such training may be possible. There can be better possibilities to use HMDs for short and long-distance or peripheral vision training. However, for this the HMD technology and handling graphics in HMDs also needs to be improved. However, there are already some examples. Nowak and his colleagues [44] showed the potential of using HoloLens (a see-through HMD using physical space and virtual images) for the rehabilitation of amblyopia (lazy eye) in children, and Ziak et al. [45] used HMD's for adults.

#### *5.3. Enablers (for Using Technologies)—Are Not Necessarily the Users*

One of the main benefits of starting this project was realizing that the enablers for using the technologies are vision experts. Their opinions is not only important for their expertise with handling vision difficulties but also their willingness and competencies for handling the technologies.Their user experiences may differ from the end-user's (the children's) wishes for games but necessary fo accepting the games for rehabilitation tools.  Possibilities for Developing Future Games*

Since literature demonstrates that positive results can be achieved already after 3–6 week vision training, different new possibilities to make this training need to be investigated. One option is to understand whether it is possible to perform parts of the training alone or be supported by nonprofessionals, and also better understand the role of the professionals and how they can be involved.

Vision screening using ET produces *measurable*, objective results and is a valuable tool for identifying OMD. When training is performed, this method can also be used to evaluate progress. Today screening and training are separate activities and are done by using screening and training software packages separately. However, by integrating evaluation into the games-based training software, using ET technology, it is possible to create training software where the user may perform training and assess progress, potentially without continuous professional support and supervision (see above). At the very first step we develop measurement methods for the necessary aspects from Tables 1 and 2 regarding OMD activities for the suggested games.

Having an OMD screening program in the background will allow measuring the progress automatically and immediately. We have made use of affordable ET hardware, and our goal is to make the software open source. This contrasts with existing computerized solutions for OMD, which to our knowledge, uses proprietary software and expensive ET hardware. One of the main motivations behind this is the intention to make the programs usable for many. The possibilities to access data from many users mean that AI algorithms can identify and develop more supportive training solutions.

#### **6. Conclusions**

This project has shown the design of a prototype system for vision training with three VTs, which has been tested by five other VT students, evaluating several aspects of its quality and usefulness with the main qualities to trigger the same eye movements as the necessary eye movements with today's non computer supported vision training.

By this the study shows the possibility of integrating computer games into the vision rehabilitation process from the VTs perspective, by considering concrete rehabilitation goals and designing games to find measurable aspects supporting training and training fulfillment. Based on guidelines for creating a training program for children who struggle with OMD, we have created a collection of exercises based movements implemented in six computer games and evaluated them by Norwegian and Tanzanian vision experts and found and presented a number of issues needed to be taken in consideration for further development and acceptability for supporting rehabilitation.

Another benefit of this study can be the interdisciplinary approach it follows. While several stakeholders from different domains are involved in developing games for rehabilitation, this is a long and complex process, requiring intense collaboration for translating goals from one domain into goals in another domain. While the results are only partial, they have to be discussed within the scientific community. For this process, we consider Grounded Design helpful.

**Author Contributions:** Conceptualization, I.H., C.H., and D.P.; methodology, I.H.; software, H.P. and A.B.G.; validation, H.P., I.H. and A.B.G.; formal analysis, I.H. and Q.A.; investigation, I.H., C.H.; resources, I.H. and C.H.; data curation, H.P. and C.H.; writing—original draft preparation, I.H.; writing—review and editing, I.H., C.H., D.P. and Q.A.; visualization, I.H., A.B.G. and H.P.; supervision, I.H. and C.H.; project administration, I.H.; funding acquisition, I.H and C.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This paper is financed by the Vision 2030 project, Securing education for children in Tanzania. Funding N.F.R., Project no: 267524/H30.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.

**Acknowledgments:** Thanks to the vision teachers and educators Gunvor Birkeland Wilhelmsen, Tina Ihler, Heidi Jåstad, and our colleagues Harald Soleim, Mads Gjerstad Eide, Ruben Watanabe. Much of this paper is based on the MSc works of Håvard Homme Pettersen (HP) on vision training [70] and Mads Gjerstad Eide and Ruben Watanabe on vision screening [48].

**Conflicts of Interest:** The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

#### **References**


**List of symbols**

CSTR). In **Figure 14**, at low stoichiometric value, a depletion of reactants can be observed close to the outlet, thus generating a cathodic overpotential increase and a dramatically current density decrease in this part. It is interesting to note that water molar fraction increases at the cathode side in connection to the electroosmotic drag of water, from anode to cathode, and the insufficient "back-diffusion" from the cathode to anode. Water transport and production at the cathode result in increasing water content at the cathode side along the gas channel while it decreases at the

*Simulation of local oxygen (*■*) and water () molar fraction distribution along the channel (rO2 = 2.2 for dry*

*Simulation of local current density distribution along the channel (rO2 = 2.2 for dry conditions at T = 60°C with*

This study has drawn attention to the relative advantages of using a CSTR description. Moreover liquid water phase only exists at the cathode side, thus leading to the polymer drying out at the anode and consequently increasing ohmic resistance. In the future, it will be important to include the flooding or partial

flooding effects that were not taken into account in this study.

anode side.

**96**

**Figure 14.**

*conditions at T = 60°C with |ηc| = 0.55 V).*

**Figure 13.**

*|ηc| = 0.55 V).*

*Thermodynamics and Energy Engineering*


**3. Quasi-stationary states**

*Magnetometers - Fundamentals and Applications of Magnetism*

appears; at high energy, a homogeneous phase emerges.

λ

where the variable *pi* is the momentum of the particle *i*, and

The equations of motion are derived by the following set:

ε

where the components of the magnetization vector are defined as

( ) (

*M M*

β

where *Ik* (…) is the *k*th-order modified Bessel function,

tion *mc* = 0. The specific heat diverges with the temperature 1/

β

an approach to the understanding of magnetic materials.

combined with the extremal solution

ε λ = + +∆ 2 1 2 , *m* /2

= ≠

*i i j*

*N N*

1

**2. Equilibrium**

[9, 10] given by

eter λ

The evolution of simulations permits us to observe several properties that are not possible to identify with any theoretical description. The interpretation comes from perceiving regularities in the dynamics of systems as HMF and d-HMF models.

As generally noticed, at low energy, a phase of a single cluster of particles

For theoretical and numerical modeling, we consider a system of N identical, coupled, dipole-type particles with a mass equal to 1. The dynamics evolves in a periodic cell described by a one-dimensional, dipole-type HMF model (d-HMF)

( )

1 cos 3cos cos , 2 2

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 θ θ

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is the inverse of

→ − 1 and remains

*H p N* (1)

,

θ

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(4)

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sponding angle of orientation (integer *i* ∈ [1,*N*] for the system size *N*). The param-

stands for the coupling and ∆*i j* , suitably denotes the zero of the potential.

( )

θ θ)

θ

≠ = ∑ 1 , cos ,sin . *N x y i i i j*

After deriving thermodynamic properties in both, the canonical and microcanonical ensembles, the caloric curves come from the following coincident result:

( ( ))

( ) ( ) βλ

2 , 2

is the energy per particle; *m* is the magnetization per particle. We

> 1 , which corresponds to an ideal gas in one dimension.

βλ = 1 0

analytically obtain the parameters that define the critical point, such as the critical inverse temperature *β*c = 1, critical internal energy *ε*c = 3/2, and critical magnetiza-

Therefore, systems with magnetic behavior are recently studied in [11, 12], giving

This type of solutions is not common in physics and particularly in statistical mechanics, especially regarding long-range interactions [9]. Baxter gives a

As said before, this system denotes an analytically solvable many-body problem.

**4**

temperature,

ε

in a constant value for 1/

The statistical mechanics thoroughly explains the equilibrium, which is the statistical state reached in the long-lasting evolution. Nevertheless, in intermediate intervals of the evolution time, the dynamics is abnormal, and the description is not complete. Therefore, there are at least two regimes in the evolution of systems with long-range interactions: the equilibrium and the quasi-stationary states (QSS). In the first case, we have the Boltzmann-Gibbs statistics to describe the state of the systems entirely. In the second, it is an open problem that possesses several theoretical attempts susceptible to improve them.

Generally speaking, when the modeling neglects all of the spatial structure of the system but considers long-range interactions, mean-field approximations should be good alternatives to consider. The d-HMF model is curious because it neglects the structure of systems and space interactions, and only keeps the part related to orientations, but shows axiomatic and pertinent properties.

To identify the QSS, we search for intervals where the thermodynamic values keep constant. Therefore, **Figure 1(a)** illustrates two plateaus in the behavior of magnetization per particle as a function of time, before equilibrium. A complementary perspective of the first QSS given in [10] considers the shape of the mean kinetic energy per particle, aiding us to obtain the power-law duration depicted in **Figure 1(b)** that characterizes the nature of QSS. States defined by the plateaus of mean kinetic energy per particle are lower than the canonical temperature, whose values only coincide in equilibrium [10].

Finally, this system constitutes an example of a non-symmetric HMF that shows a phase transition, the appearance of a spontaneous magnetic ordering. The symmetry is compared to the HMF model that remains invariant under a typical rotational transformation, which is not valid for the d-HMF model, but presents a second-order phase transition; therefore, a possible application found in the literature is the phase transition of non-symmetric spin glasses. Theoretical background for systems out of equilibrium is not unique and fundamental questions related

#### **Figure 1.**

*The magnetization per particle is depicted as a function of the time in (a). In (b), the relaxation time τ, of the first QSS that goes to the second QSS, is depicted as a function of 1/N in log–log scale, whose power law of the duration of the first QSS in terms of the system size is obtained from the behavior of the kinetic energy.*

to this issue are still open; a possible description based on a family of solutions of Vlasov equation is in progress [14].

The understanding of these thermodynamic properties can be fundamental in future demands as the manufacturing of magnetic instruments, sensors, and magnetometers.


*Article* **Application of CFD to the Design of Manifolds Employed in the Thermodynamic Method to Obtain Efficiency in a Hydraulic Turbine**

**Erick O. Castañeda Magadán, Gustavo Urquiza Beltrán, Laura L. Castro Gómez \* and Juan C. García Castrejón**

Centro de Investigación en Ingeniería y Ciencias Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico<EMAIL_ADDRESS>(E.O.C.M<EMAIL_ADDRESS>(G.U.B<EMAIL_ADDRESS>(J.C.G.C.)

**\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** This study presents the design and implementation of different types of manifolds (sampling system) to measure water flow properties (velocity, pressure, and temperature) through the high- and low-pressure section of a Francis-type low head hydraulic turbine (LHT of 52 m) to calculate it is efficiency using the Thermodynamic Method (TM). The design of the proposed manifolds meets the criteria established in the "International Electrotechnical Commission—60041" Standard for the application of the TM in the turbine. The design of manifolds was coupled to the turbine and tested by the Computational Fluid Dynamics (CFD) application, under the same experimental conditions that were carried out in a power plant, without the need for on-site measurements. CFD analyses were performed at different operating conditions of volumetric flow (between values of 89.67 m3/s and 35.68 m3/s) at the inlet of turbine. The mechanical power obtained and the efficiency calculated from the numerical simulations were compared with the experimental measurements by employing the Gibson Method (GM) on the same LTH. The design and testing of manifolds for high- and low-pressure sections in a low head turbine allows for the constant calculation of efficiency, avoiding breaks in the generation of electrical energy, as opposed to other methods, for example, the GM. However, the simulated (TM) and experimental (GM) efficiency curves are similar; therefore, it is proposed that the design of the manifolds is applied in different geometries of low-head turbines.

**Keywords:** computational fluid dynamics; hydraulic efficiency; Gibson method; manifolds; turbine; thermodynamic method


**Acknowledgements**

The support of FONDECYT (Preis 3140076, Preis 1140239 and Preis 1120764), FONDEF (Preis IT13I10034), CORFO (Preis 14BPC4‐28651), USACH‐DICYT ASOCIATIVO, SEP‐PROMEP Preis 14146 F‐38, and UTFSM‐DGIP, CONICYT‐PCHA/Doctorado Nacional<PHONE_NUMBER>65, is gratefully acknowledged. Some parts of the chapter are part of the previously published papers [18, 21, 22].