**Randal Joy Thompson**

Randal Joy Thompson, Ph.D., MBA, MA, is a Fellow at the Institute for Social Innovation, Fielding Graduate University. She is also an international development professional and former US Commissioned Foreign Service Officer. She is currently the co-editor of the book series Transformative Women Leaders, published by Emerald. Her books include Embodied Somatic Leadership for Peacebuilding and Protest: Women's Counteroffensive to Violence and Injustice, co-edited with Lazarina Topuzova (2024, forthcoming); Reimagining Leadership on the Commons: Shifting the Paradigm for a more Ethical, Equitable, and Just World, co-edited with Devin Singh and Kathleen Curran (2021); Proleptic Leadership on the Commons: Ushering in a New Global Order (2020); and Leadership and Power in International Development: Navigating the Intersections of Gender, Culture, Context, and Sustainability, co-edited with Julia Storberg-Walker (2018), which won the Human Resource Development R. Wayne Pace HRD Book of the Year Award. Her book chapters cover female leaders in Afghanistan, post-war Bosnia-Herzegovina, Myanmar, and Morocco. She conceived a theory of leadership in international development based on women's way of knowing and recently published two articles on violence against women and LGBTQI+ individuals in El Salvador. She holds a Ph.D. in Human and Organizational Behavior from Fielding Graduate University, an MA in Philosophy and an MBA from the University of Chicago, an MA in Biblical Exposition from Capitol Seminary and Graduate School, and a BA in Philosophy from the University of California, Berkeley. She was President of the International Leadership Association's Women and Leadership Community in 2021.


**An Investigation of the Effects of Changes in the Indoor Ambient Temperature on Arousal Level, Thermal Comfort, and Physiological Indices †**

#### **Jongseong Gwak 1,\*, Motoki Shino 2, Kazutaka Ueda 3 and Minoru Kamata 2**

Received: 30 January 2019; Accepted: 26 February 2019; Published: 3 March 2019

**Abstract:** Thermal factors not only affect the thermal comfort sensation of occupants, but also affect their arousal level, productivity, and health. Therefore, it is necessary to control thermal factors appropriately. In this study, we aim to design a thermal environment that improves both the arousal level and thermal comfort of the occupants. To this end, we investigated the relationships between the physiological indices, subjective evaluation values, and task performance under several conditions of changes in the indoor ambient temperature. In particular, we asked subjects to perform a mathematical task and subjective evaluation related to their thermal comfort sensation and drowsiness levels. Simultaneously, we measured their physiological parameters, such as skin temperature, respiration rate, electroencephalography, and electrocardiography, continuously. We investigated the relationship between the comfort sensation and drowsiness level of occupants, and the physiological indices. From the results, it was confirmed that changes in the indoor ambient temperature can improve both the thermal comfort and the arousal levels of occupants. Moreover, we proposed the evaluation indices of the thermal comfort and the drowsiness level of occupants using physiological indices.

**Keywords:** thermal comfort; arousal level; physiological indices; electroencephalography; electrocardiography

#### **1. Introduction**

The control of indoor environmental quality (IEQ, which consists of visual elements, olfactory elements, and thermal factors, etc.) is important for improvements of the comfort and productivity of occupants. Among the factors of IEQ, thermal factors, such as ambient temperature, radiant temperature, humidity, and air velocity, are especially related with not only the thermal sensation and thermal comfort of occupants, but also productivity and health. With the high technology of heating, ventilation, and air conditioning systems (HVAC systems), the relationship between thermal factors and thermal sensation and thermal comfort has received attention from several researchers worldwide. In previous research, indices of thermal comfort, such as the predicted mean vote (PMV), predicted percent dissatisfied (PPD), and standard new effective temperature (SET\*), have been proposed based on the relationship between thermal factors and the subjective evaluation of thermal comfort

sensation [1,2]. Many studies have analyzed the indoor thermal quality based on the evaluation of thermal factors using these indices [3–7].

In addition, improvements of the productivity of occupants who are working, studying, and driving in indoor spaces, such as offices, classrooms, and vehicles, are needed. It is necessary to maintain a high arousal state of the occupants to improve their productivity. In previous studies, it was shown that productivity improved when the arousal level of occupants was high, and this was related to the indoor ambient temperature that occupants felt as cool or cold [8,9]. From the results of previous studies, the conditions of the ambient temperature to improve task performance were different from the conditions of the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers)'s thermal comfort zone [10]. Therefore, the conditions of the constant ambient temperature were not appropriate to improve both the task performance and thermal comfort levels. In previous studies, it was shown that the thermal comfort of occupants was immediately changed in accordance with changes in the indoor ambient temperature [11]. The arousal level was increased by outer stimulation and was maintained at a high state for several minutes [12,13]. Based on these results of previous studies, we hypothesized that thermal stimulation due to cooling can improve the arousal level of occupants. Furthermore, thermal comfort can be improved while maintaining high arousal levels due to the removal of thermal stimulation. When considering the possibility that changes in thermal factors can improve both arousal and thermal comfort levels, the physiological effects associated with such changes in thermal factors, and how they affect the arousal level and thermal comfort of occupants are not clear. Therefore, the design requirements for changes in ambient temperature to improve both the arousal level and thermal comfort are also not clear. Therefore, a continuous and quantitative evaluation of the thermal comfort and arousal level of occupants using indices, which can be measured both continuously and quantitatively, such as physiological signals, is needed to clarify the design requirements of changes in the indoor ambient temperature to improve both the arousal level and thermal comfort.

In this study, we aimed to investigate the characteristics of changes in the arousal level and feelings of thermal comfort of occupants, and the relationship between them when thermal factors are changed. There are many factors that affect the thermal comfort and arousal level of occupants, such as the ambient temperature, indoor air velocity, mean air radiant temperature, and metabolic activity [5–7]. Especially, we focused on the changes in the indoor ambient temperature as a fundamental investigation in this study. In addition, to propose evaluation indices that can evaluate the thermal comfort and arousal level of occupants continuously and quantitatively, we investigated the relationship between the arousal level, feelings of thermal comfort, and physiological indices, which can be measured continuously and quantitatively.

#### **2. Strategy**

#### *2.1. Investigation of the Effects of Changes in the Indoor Ambient Temperature on Arousal Levels, Thermal Comfort, and Task Performance*

To verify the hypothesis that thermal stimulation, due to cooling, can improve the arousal level of occupants, and that thermal comfort can be improved while maintaining high arousal levels due to the removal of thermal stimulation, several thermal conditions were set. Subjects were asked to conduct a mathematical task and periodically evaluate their sensation values (using a subjective sensation vote) in relation to their arousal level and thermal comfort. We attempt to clarify the effect of changes in the indoor ambient temperature on the arousal level, thermal comfort, and task performance of occupants by conducting an analysis of the results of the subjective sensation vote and task performance.

#### *2.2. Investigation of the Relation between the Subjective Evaluation Value and Physiological Parameters, and a Recommendation for Evaluation Indices*

Indices that can evaluate the arousal and thermal comfort levels of occupants continuously and quantitatively are necessary to clarify the design requirements of a temperature control that can improve the arousal and thermal comfort levels of occupants. However, as it was not possible to perform a subjective sensation voting continuously, we considered clarifying the design requirements for thermal environments using changes over time. This relied on the possibility to evaluate the arousal level and feelings of thermal comfort using physiological parameters that could be measured quantitatively and continuously. Previous studies have shown that the physiological indices measured utilizing electroencephalograms (EEG), electrocardiograms (ECG), and respiration rates were effective for the evaluation of arousal levels [14,15], and the skin temperature, EEGs, and ECGs of occupants were effective for the evaluation of the thermal comfort [16,17]. Therefore, in this study, we assumed a flow of physiological responses when the occupant was stimulated by thermal factors, as shown in Figure 1, based on the above-mentioned previous studies to clarify the characteristics of the physiological parameters under the condition of changes in both the arousal level and thermal comfort. A thermal stimulation is transmitted from the sensory organ, such as warm spots and cold spots of skin, to the central nervous system, which affects thermal and comfort sensation. This change in comfort sensation then affects the autonomic nervous system, and the response is then conducted through the locomotive organ. Based on this process, we selected the skin temperature as an indicator of heat transfer between the environment and the human body, EEGs as an indicator of the reaction of the central nervous system, and ECGs as indicators of the reaction of the autonomic nervous system. Next, we attempted to search for indices that could separately evaluate the arousal level and thermal comfort by performing a multiple regression analysis utilizing the physiological parameters and subjective evaluation values of the arousal level and feelings of thermal comfort. In Figure 1, the flow of physiological responses with the thermal stimulus is shown.

**Figure 1.** Flow of physiological responses with the thermal stimulus.

#### **3. Methodology**

#### *3.1. Subjects*

Ten subjects with vital statistics of a height of 173.5 ± 4.4 cm, weight of 61 ± 4.8 kg, age of 22.1 ± 1.2 years old, and who were right-handed participated in the experiment. The experimental contents and procedures, which were approved by the ethics committee of the University of Tokyo, were explained to the subjects before conducting the experiment. The subjects were then asked to avoid intense physical activity, alcohol, and caffeine for 24 h prior to the experimental session.

#### *3.2. Experimental Task*

The subjects were asked to conduct mental arithmetic tasks known as "MATH", which is based on the algorithm proposed by Tuner et al. [18]. A 1–3-digit addition or subtraction question is displayed for 2 s on the monitor, and then "equals to" is displayed for 1.5 s. Lastly, the answer is displayed for 1 s, and the next question is displayed after 0.5 s. Subjects had to determine if the answer was correct or incorrect when the answer was displayed and click the left mouse button if the answer was correct or the right mouse button if the answer was incorrect. The levels of questions in the original version of MATH consisted of 1–5 levels. In this study, the beginning level was 3 (which is 2-digit addition or subtraction), and the level of the next question was raised if the responses of the subjects were correct, and was reduced if answers were incorrect. We deduced that changing the levels affected

the physiological indices. Thus, we did not change the level of the question, and fixed it to level 3. The MATH task included 50 questions for 250 seconds per set.

#### *3.3. Experimental Conditions and Experimental Procedure*

To evaluate the effects of the duration and degree of thermal stimulation, three environmental conditions (A–C) were set as follows.

We set condition A as a thermally comfort condition [10], and condition C as a high arousal condition [8,9]. Condition B was set to verify the hypothesis that thermal stimulation due to cooling can improve the arousal levels of occupants, after which thermal comfort can be improved while maintaining high arousal levels due to the removal of thermal stimulation. There are many parameters which affect the thermal comfort and arousal levels of occupants, such as the indoor velocity, mean air radiant temperature, metabolic activity, and amount of clothing. In this study, we focused on only the indoor ambient temperature as a fundamental investigation, thus those parameters except the indoor ambient temperature were controlled in the experiment. The subjects wore short sleeves and short pants and were asked to remain in the pre-room. The room temperature was set at 27 ± 0.5 ◦C for approximately 1 h so that subjects could adjust to the thermal environment; they were asked to practice the "MATH" at least twice during this time. Sensors were then attached to the bodies of the subjects to measure their physiological indices. One set of tasks consisted of completing the subjective sensation vote and the "MATH" task. The subjects were asked to perform seven sets of tasks at time intervals of 10 min and to rest between each task for approximately 3 min. Physiological indices were measured from the start time (0 min) till the end time (70 min). The experimental procedure and environmental conditions are shown in Figure 2.

**Figure 2.** Experimental conditions and environmental procedure.

#### *3.4. Measurement*

3.4.1. Subjective Evaluation of the Drowsiness Level and the Thermal Comfort Sensation

Before completing the "MATH" task, the subjects were asked to complete a questionnaire related to their thermal sensation, thermal comfort sensation, and arousal level. The scale of thermal sensation was based on ASHRAE/ISO (International Organization for Standardization) [10], and was denoted using integral numbers from −3 to 3 (where −3, −2, −1, 0, 1, 2, and 3 are the meanings of cold, cool, slightly cool, neutral, slightly warm, warm, and hot, respectively.). The scale of comfort sensation was based on ISO10551 [19], and was denoted using integral numbers from −3 to 0 (where −3,

−2, −1, and 0 are the meanings of very uncomfortable, uncomfortable, slightly uncomfortable, and comfortable, respectively.). The scale of the arousal level was based on the drowsiness level of Zilberg's indicators [20], and was denoted using integral numbers from 0 to 4 (where 0, 1, 2, 3, and 4 are the meanings of alert, slightly drowsy, moderately drowsy, significantly drowsy, and extremely drowsy, respectively.).

#### 3.4.2. Physiological Indices

#### (a) EEG

EEGs were recorded using an EEG-measuring instrument (EEG-1200, Nihonkohden Co., Japan) at a sampling rate of 500 Hz. EEG electrodes were attached on 16 channels (based on the internationally accepted 10–20 system, Fp1, Fp2, F7, F3, F4, F8, T7, C3, C4, T8, P7, P3, P4, P8, O1, O2). Next, raw data were processed using the Fourier transform method, and the spectral power of each frequency band, such as the content of theta wave (4–8 Hz), low-alpha wave (8–10 Hz), high-alpha wave (10–13 Hz), low-beta wave (13–20 Hz), high-beta wave (20–30 Hz), and SMR (12–15 Hz) bands, was calculated in addition to the values of the beta per alpha and alpha per high-beta for each channel.

#### (b) ECG

ECGs were recorded using an ECG-measuring instrument (WEB-7000 and ECG picker, Nihonkohden Co., Japan) at a sampling rate of 1000 Hz. Three electrodes were attached to the chests of subjects using the precordial leads method. The R-R interval (RRI) was calculated from the ECG waveform using MATLAB (Mathwork Co.) programs. The values of the mean of the RRI and the coefficient of variance of RRI [CVRR (100\*SD/Mean of RRI)] were calculated from the RRI data. In addition, the spectral power of each frequency band, such as the very low frequency (VLF, 0.001–0.04 Hz), low frequency (LF, 0.04–0.15 Hz), and high frequency (HF, 0.15–0.45 Hz) bands, was calculated from the time series of the RRI using the fast Fourier transform method.

#### (c) Respiration

A thermal picker (WEB-7000, Nihonkohden Co., Japan) was used to measure the temperature of the breath of subjects. The peak values in the time series graph of the temperature were detected, and the mean and standard deviation of the respiratory cycle time were calculated.

#### (d) Skin Temperature

Thermocouples were attached at 7 places on the bodies of subjects based on the Hardy–Du Bois method [16] to measure the skin temperature (LT8, GRAM Co., Japan). Finally, the mean skin temperature was calculated using following Equation (1):

$$MST = 0.07\ T\_1 + 0.14\ T\_2 + 0.05\ T\_3 + 0.35\ T\_4 + 0.19\ T\_5 + 0.13\ T\_6 + 0.07\ T\_7\tag{1}$$

where *MST* is the mean skin temperature based on the Hardy-DuBois method [16], and *T*1, *T*2, *T*3, *T*4, *T*5, *T*6, and *T*7 are the temperatures of the forehead, forearms, hands, abdomen, thighs, legs, and feet, respectively.

#### 3.4.3. Facial Expression and Task Performance

The activities of subjects were recorded using the video camera, and the drowsiness levels were recorded by an observer at intervals of 10 s based on Zilberg's criteria [20]. After the experiment was completed, the mean of the data recorded when subjects were performing the MATH task was calculated. The task performance of MATH included the number of correct answers and the mean of the reaction time taken to solve 50 questions. Figure 3 shows a participant completing the experiment. Figure 3 shows photos of the field of experimental scene.

**Figure 3.** Field photos of the experimental scene.

#### **4. Results and Discussion**

*4.1. Characteristics of the Arousal Level and Thermal Comfort Corresponding to Changes in the Indoor Ambient Temperature*

#### 4.1.1. Subjective Evaluation Value

The results of the subjective evaluation value corresponding to the drowsiness levels and the thermal comfort sensation vote of subjects under conditions A, B, and C are shown in Figures 4 and 5. We used multiple comparison based on the Bonferroni method to investigate significant differences of the subjective evaluation value due to changes in the indoor ambient temperature. There was a small change in the comfort sensation vote, but the drowsiness level increased under condition A, where the indoor temperature was maintained at 27 ◦C. Under condition B, the comfort sensation vote decreased to an uncomfortable state when the indoor ambient temperature dropped, and increased to a comfortable state when the indoor ambient temperature increased. Under condition C, the comfort sensation vote decreased to an uncomfortable state when the indoor temperature decreased and was then maintained in this uncomfortable state. Under conditions B and C, the drowsiness levels decreased and were maintained at an alert state, corresponding to the drop in the indoor temperature. After the completion of set 4, the comfort sensation vote increased, corresponding to the increase in the indoor temperature under condition B, but was maintained at an uncomfortable state under condition C. The drowsiness level was maintained at a low state under both conditions. According to this result, the arousal level was maintained at a high state even when the temperature increased, and subjects felt comfortable even when the temperature dropped, leading to an increased arousal level. This suggests that there is not always a dependence relationship between the arousal levels and feelings of thermal comfort. Figures 4 and 5 show that when condition B is applied in sets 6 and 7, it becomes possible to improve both the arousal level and thermal comfort of occupants by changing the indoor ambient temperature. These results show that the hypothesis that thermal stimulation due to cooling can improve the arousal level of occupants, after which thermal comfort can also be improved while maintaining a high arousal levels due to the removal of thermal stimulation was verified for condition B. Figure 4 shows the result of the thermal comfort sensation vote. Figure 5 shows the result of the drowsiness level sensation vote.

**Figure 4.** Results of the value of the thermal comfort sensation vote.

**Figure 5.** Results of the value of the drowsiness level sensation vote.

#### 4.1.2. Rating Value of Zilberg's Drowsiness Level by Observer

The rating values of Zilberg's drowsiness level for each condition are shown in Figure 6, and it is evident from the figure that the results are similar to those of the subjective sensation vote. Multiple comparison based on the Bonferroni method was conducted to investigate significant differences of the drowsiness level due to the changes in the indoor ambient temperature. After the completion of set 3, the drowsiness levels under conditions B and C decreased significantly compared to that under condition A. From the result of condition B, it was confirmed that the drowsiness level was maintained at a low state after the completion of set 3.

**Figure 6.** Drowsiness level reached when calculating MATH (analysis of facial expressions based on Zilberg's method [20]).

#### 4.1.3. Task Performance of MATH

The results of the MATH score under each condition are shown in Figure 7, and the results of the response time taken to calculate MATH questions under each condition are shown in Figure 8. Multiple comparison based on the Bonferroni method was conducted to investigate significant differences in the task performance due to changes in the indoor ambient temperature. It can be seen from Figures 7 and 8 that the MATH score was high after set 4, and the response time taken to calculate MATH questions increases in the order of conditions C, B, and then A. Differences were observed between the conditions in the results of the subjective sensation vote and the rating value of Zilberg's drowsiness level. However, significant differences were observed only between the conditions in the result of the response time taken to calculate MATH for set 4, and the result of the MATH score for set 5. It was assumed that the MATH work was easy enough for the subjects to perform, even at a low state of arousal. Figure 6 shows the drowsiness level reached when calculating MATH (analysis of facial expressions based on Zilberg's method [20]). Figures 7 and 8 show the result of the MATH score and the response time from the display of the MATH question to the participant's click.

**Figure 8.** Result of response time.

#### 4.1.4. Consideration of Thermal Stimulation for High Arousal Levels

In the previous studies of Yoshida et al. [12] and Mohri et al. [13], to maintain a high arousal level, the effects of several stimulation methods, such as the use of a fragrance, alarm, and shoulder oscillation, were confirmed. As a result, the sleeping rebound occurred 10 min after the stimulation in those studies. As in our results, high arousal states were maintained for over 10 min after the removal of thermal stimulation. Though further investigation of these comparisons of the time to rebound is necessary, our results showed that thermal stimulation is effective in improving the arousal levels of occupants. Especially, our method is useful in spaces where air conditioning systems are installed, because the installation of additional devices in the space to make stimulations, such as fragrances, alarms, and shoulder oscillation, is unnecessary.

#### *4.2. Relationship between the Subjective Evaluation Value and Physiological Indices*

Three hundred and twenty-nine physiological indices were calculated by using the data of the EEGs, ECGs, respiration rate, and mean skin temperature in the experiment (320 indices from EEGs, 7 indices from ECGs, 2 indices from respiration rate, and 1 index from skin temperature). By considering the result of the subjective evaluation value as the standard for the perception of state, we used correlative analysis to investigate the relationship between the subjective evaluation value and the physiological indices. According to the flow of the physiological response shown in Figure 1, changes in both the arousal level and thermal comfort affect the physiological response. To find indices (out of the 329 physiological parameters) that corresponded to the arousal level, we used data from sections when the arousal level changed, but the value of the thermal comfort sensation was maintained constantly. On the other hand, to find indices that corresponded to thermal comfort, we used data from sections when the value of the thermal comfort sensation changed and the arousal level was maintained constantly.

#### 4.2.1. Relationship between the Drowsiness Level and Physiological Indices

As a result of the correlation analysis, the correlation coefficients between values of the drowsiness level vote and physiological indices were calculated using data from 57 sets in which the value of the drowsiness level vote varied, but the value of the comfort sensation vote remained at 0 (comfortable). There was a significant correlation between the drowsiness level and 102 physiological indices (data *N* = 57, *r* > 0.339, *p* < 0.01). The indices in relation to the ECGs were not included in these parameters; however, the indices in relation to the EEGs were included. Thus, this result showed that the relationship between the reaction of the central nervous system and changes in arousal levels is more significant than that between the reaction of the autonomic nervous system and changes in arousal levels.

#### 4.2.2. Relationship between Thermal Comfort and Physiological Indices

As a result of the correlation analysis, the correlation coefficients between the values of the comfort sensation vote and physiological indices were calculated using the data from 98 sets in which the value of the comfort sensation vote varied, but the value of the drowsiness level vote was between 0 (alert) and 1 (slightly drowsy). There was a significant correlation between the value of the comfort sensation vote and seven physiological indices in relation to skin temperature, EEGs, and ECGs (data *N* = 98, *r* > 0.259, *p* < 0.01). The change in the mean skin temperature is related to thermal stimulation from the outer environment, which is transmitted to the central nervous system and perceived as thermal comfort, thus affecting the parameters of the EEGs. It was observed that changes in the thermal comfort affected the autonomic nervous system, which in turn affected the indices in relation to the ECGs. It appears that this process affected the result of the correlation analysis in this experiment.

#### 4.2.3. Calculation of the Evaluation Index Using Multiple Regression Analysis

To propose an index that evaluates the changes in each arousal level and thermal comfort states, multiple regression analysis was performed using the physiological indices that have a significant correlation with the value of subjective evaluation. It was found that 102 parameters had a significant correlation with the drowsiness level vote, and seven parameters with the comfort sensation vote. These were thus considered as explanatory variables. Because an explanatory variable should have a high correlation with the subjective sensation vote, to obtain a high multiple regression coefficient, we selected an explanatory variable for use in the multiple regression analysis using the following process.

#### (a) Evaluation Index indicating the Arousal Level

The result of the multiple regression analysis 1 (*Yd*) is shown in Table 1, and the regression equation obtained from the result is expressed in Equation (2). The variables of the regression equation include the indices of the EEGs. As a result, the coefficient of determination, *R*2, in relation to *Yd* was 0.750.

$$Yd = -3.31 + 0.134 \text{ X}d\_1 + 2.520 \text{ X}d\_2 + 0.088 \text{ X}d\_3 - 0.268 \text{ X}d\_4 + 0.271 \text{ X}d\_5 \tag{2}$$

where *Xd*1, *Xd*2, *Xd*3, *Xd*4, and *Xd*5 are the high alpha content of T7, beta per alpha content of F7, beta content of F3, low beta content of F7, and alpha content of Fp1, respectively.

**Table 1.** Result of multiple regression 1 (*Yd*).

We defined *Yd* as the index of the arousal level. To confirm the possibility that *Yd* can evaluate the arousal level even when the thermal comfort changed, we calculated *Yd* from the data obtained from five subjects for whom the arousal level and thermal comfort changed considerably, and then performed a correlation analysis between *Yd* and the evaluation value of the drowsiness level. As a result of the correlation analysis, the correlation coefficient (*R*) was calculated to be 0.726, and there was a significant correlation between *Yd* and the evaluation value of the drowsiness level. Therefore, this result suggests that *Yd* can be used to evaluate the drowsiness level, even when there are changes in the thermal comfort.

#### (b) Evaluation Index Indicating Thermal Comfort

The result of the multiple regression analysis 2 (*Yc*) is shown in Table 2, and the regression equation obtained from the result is expressed in Equation (3). The variable for the regression equation included the indices of the skin temperature and EEGs. As a result, the coefficient of determination, *R*2, in relation to *Yc* was 0.528.

$$\text{Yc} = -23.372 + 0.697 \text{ Xc}\_1 + 0.172 \text{ Xc}\_2 + 0.142 \text{ Xc}\_3 \tag{3}$$

where *Xc*1, *Xc*2, and *Xc*3 are the *MST* (Mean Skin Temperature), alpha per high-beta content of C4, and alpha per high beta content of P4, respectively.

**Table 2.** Result of multiple regression 2 (*Yc*).

We defined *Yc* as the index of thermal comfort. To confirm the possibility that *Yc* can evaluate thermal comfort even when there were changes in the drowsiness level, we calculated *Yc* from the data of nine subjects, excluding the data of participant *D* whose thermal comfort vote and drowsiness level vote changed slightly. We thus confirmed the relationship between *Yc* and the value of thermal comfort. As a result, the correlation coefficient (*R*) was calculated to be 0.728, and there was a significant correlation between *Yc* and the value of thermal comfort (*p* < 0.01). Therefore, this result suggests that *Yc* can be used to evaluate thermal comfort even when there are changes in the drowsiness level.

Table 1 shows the result of the multiple regression 1 (*Yd*), and Table 2 shows the result of the multiple regression 2 (*Yc*). Figure 9 shows the relationship between the drowsiness level vote and *Yd*(a), and the relationship between the comfort sensation and *Yc* (b)

**Figure 9.** The relationship between the drowsiness level and *Yd* (**a**), the comfort sensation and *Yc* (**b**).

(c) Review of Continuous Evaluation using *Yd* and *Yc*

As mentioned in Section 2.2., indices that can continuously evaluate the drowsiness level and thermal comfort of occupants are needed to clarify the design requirements related to thermal factors that can improve these states of the occupants. Therefore, we conducted a time-series analysis with *Yd* and *Yc* to confirm the possibility that *Yd* and *Yc* can continuously evaluate arousal levels and thermal comfort. We calculated the time series of *Yd* using data from subject C, who seemed to be drowsy frequently throughout the experiment, and compared these data with those of the drowsiness level, which was recorded at intervals of 10 s by analyzing the facial expressions of the subject based on Zilberg's method [20]. The time series analyses of the normalized *Yd* and the drowsiness level of subject C are shown in Figure 10a,b. The figures clearly show the trend of changes in both indicators. It can be seen that *Yd* and values of the drowsiness level show a similar trend. For example, the red circles in Figure 10a,b indicate that values of the drowsiness level and the normalized *Yd* are higher than 3 (significantly drowsy) and 0, respectively, at the same time. Furthermore, it can be seen from Figure 11 that there is a similar trend between *Yc* and the value of the comfort sensation vote. In Figure 11a,b, the value of the comfort sensation drops to −3 (very uncomfortable) at 30 min, and at the same time, the value of *Yc* drops and becomes a negative number. Thereafter, the value of the comfort sensation vote remains at an uncomfortable state (−3: Very uncomfortable, −2: Uncomfortable), and similarly, the value of *Yc* remains at a negative value. These results suggest that *Yd* and *Yc* can be used to evaluate the drowsiness level and thermal comfort of occupants continuously. Figures 10 and 11 show, respectively, changes in the normalized *Yd* (a) and drowsiness level (b), (subject C) and changes in *Yc* (a) and the comfort sensation vote (b) (subject B).

**Figure 10.** Changes in the normalized *Yd* (**a**) and drowsiness level (**b**), (subject C): (a) Time series of normalized *Yd*, (**b**) Time series of the value of the drowsiness level.

(**b**)

**Figure 11.** Changes in *Yc* (**a**) and the value of the comfort sensation vote (**b**): Time series of the value of the comfort sensation vote, (subject B).

(d) Review of the Utility and Validity of the Evaluation Index

To review the utility and validity of the evaluation index, as an example, we set the threshold value in relation to *Yd* and the drowsiness level. When the threshold value of *Yd* is sets as 2.3, as shown in Figure 12, *Yd* can be used as the classifier, which can classify the drowsiness level between level 0, 1, 2, or more with an 86.7% accuracy. This result suggests that there is a significant difference in the physiological reaction between the drowsiness level of 1 (slightly drowsy) and 2 (moderately drowsy), and is a similar trend to the results of a previous study about the relation between the arousal levels and physiological indices of a driver [21], though the task of the subjects is different from that of the previous study (arithmetic task vs driving). This result also suggests that *Yd* is a valid indicator of the drowsiness level of occupants to classify between the drowsiness level of 1 (slightly drowsy) and 2 (moderately drowsy). Figure 12 shows the setting of the threshold value in relation to *Yd*.

**Figure 12.** Setting of the threshold value in relation to *Yd*.

#### **5. Conclusions**

In this study, we aimed to design a thermal environment that can improve the indicators of both the arousal level and feelings of thermal comfort. We hypothesized that thermal stimulation due to cooling can improve the arousal level of occupants, after which thermal comfort can be improved while maintaining high arousal levels due to the removal of thermal stimulation. To verify the hypothesis, we measured physiological indices, values of subjective evaluation, and performances of arithmetic tasks throughout several thermal conditions in which the indoor ambient temperature was changed. In addition, we investigated the relationships between them to identify the indices that can be used to evaluate the arousal levels and thermal comfort of occupants. As a result, the following findings were noted:

In future work, we will investigate the relationship between the change patterns of the indoor ambient temperature, thermal comfort, and arousal levels of occupants. After that, we aim to design a novel thermal environment, considering all comfort parameters based on these findings, with the aim of improving both the arousal levels and feelings of thermal comfort of occupants, and then carry out an evaluation of the validity of the designed thermal environment.

**Author Contributions:** Conceptualization, J.G., M.S. and M.K.; methodology, J.G., M.S., K.U. and M.K.; software, J.G.; validation, J.G.; formal analysis, J.G.; investigation, J.G.; resources, M.S., K.U. and M.K.; data curation, J.G.; writing—original draft preparation, J.G.; writing—review and editing, J.G., M.S., K.U. and M.K.; visualization, J.G.; supervision, M.S. and M.K.; project administration, M.S. and M.K.; funding acquisition, M.S. and M.K.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Formula Symbols**

#### **References**

© 2019 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 (http://creativecommons.org/licenses/by/4.0/).


**Swaminathan Ganesan 1, Sanjeevikumar Padmanaban 2,\*, Ramesh Varadarajan 1, Umashankar Subramaniam 1 and Lucian Mihet-Popa 3**

Received: 11 July 2017; Accepted: 12 September 2017; Published: 16 September 2017

**Abstract:** In this paper, a robust energy management solution which will facilitate the optimum and economic control of energy flows throughout a microgrid network is proposed. The increased penetration of renewable energy sources is highly intermittent in nature; the proposed solution demonstrates highly efficient energy management. This study enables precise management of power flows by forecasting of renewable energy generation, estimating the availability of energy at storage batteries, and invoking the appropriate mode of operation, based on the load demand to achieve efficient and economic operation. The predefined mode of operation is derived out of an expert rule set and schedules the load and distributed energy sources along with utility grid.

**Keywords:** energy management system; microgrid; distributed energy sources; energy storage system


- *CrAl- or AlCr-based combined with a ternary nitride coating*

The coating properties of (AlCrX)N can be combined with AlTiN [155,156]. There are some coating systems that contain V in a nitride coating to tailor tribological properties (formation of lubricant oxides), such as (TiV)N [157], (CrV)N and (CrMo)N [103]. The combination with (TiSi)N is focused on high hardness and oxidation stability [158].

The comination with quarternary nitride layers is a very complex approach. Many coating properties are influenced in parallel. The following systems have been explored: (AlTiSi)N [151,159], (AlCrSi)N [139,160], (TiTaAl)N [161].

The arc deposition of an fcc-(Al,Cr)ON layer on top of an fcc-(Al,Cr)N-based coating resulted in improved wear resistance [162]. The combination of alternating single layers consisting of a nitride fcc-(Al*x*Cr1−*x*)N layer followed by an oxide coating (Al*x*Cr1−*x*)2O3 with a hardness of up to 22 GPa was demonstrated [163].


**1.1.2 Yttria (Y2O3)**

198 Ceramic Coatings – Applications in Engineering

Usually cracks and fractures are observed during changing phases because of 8% volume difference while transition to tetragonal structure from monolithic structure. To avoid this and make zirconia stable in cubic structure at room temperature, alkaline earth elements such as CaO (calcium oxide), MgO (magnesia), Y2O3 (yttria) and oxides of rare elements are added to zirconia. Zirconia based ceramic materials stabilized with yttria have better properties comparing with Zirconia based ceramic materials which are stabilized by

Mechanical properties of cubic structure zirconia are weak. Transition from tetragonal zirconia to monolithic zirconia occurs at lower temperatures between 850-1000 0C and this transition has some characteristics similar to martensitic transition characteristics which are observed in tempered steels. In practice, partially stabilized cubic zirconia (PSZ) which contains monolithic and tetragonal phases as sediments, is preferred owing to its improved mechanical properties and importance of martensitic transition. Partially stabilized zirconia has been commercially categorized since early 70s. Table 2. contains partially stabilized

zirconia types and their properties. Structural properties of these materials are;

**Elasticity Module (GPa)**

ZN20: Is developed for thermal shocks. Contains (m) phase.

Table 2. Partially stabilized zirconia types and properties

Zt35: Contains 20% (t) phase in cubic matrix. Particle dimensions are about 60-70 μm.

Ca/Mg-PZS Zt35 200 4,8 1300 9,8x10-6 Mg-PZS ZN40 200 8,1 1200 9,8 Mg-PZS ZN50 200 9 900 7 Y-PZS ZN100 190 9,7 - 9,3 Mg-PZS ZN20 180 3,5 - 5,5

ZN50: Particle dimensions are about 60-70 μm and a thin film (m) phase lays on the

**Fracture Toughness (MPa m1/2)**

**Vickers Hardness (HVat 22 0C)**

**Expansion Coefficient (22-1000 0C)**

Fig. 2. Cubic, tetragonal and monolithic zirconia

ZN40: Contains 40-50% (t) phase.

borders of particles.

**Material Code**

magnesia and calcium oxide (Yaşar, 1997; Geçkinli, 1992).

Melting point of yttria is 2410 0C. It is very stable in the air and cannot be reduced easily. It can be dissolved in acids and absorbs CO2. It is used in Nerst lambs as filament by alloyed with zirconia and thoria in small quantities. When added to zirconia, it stabilizes the material in cubic structure. Primary yttria minerals are gadolinite, xenotime and fergusonite. Its structure is cubic very refractory.


**4. Conclusion**

In the current research, we studied the spatial analysis of rainfall data in 856 grid cells during the analysis period (1979–2012). The main conclusions form this study can be summarized as follows:

*Evaluation of the Spatial Distribution of the Annual Extreme Precipitation Using Kriging… DOI: http://dx.doi.org/10.5772/intechopen.101563*


*3.4. Methodology*

Data was analyzed in Qualtrics and Microsoft Excel. Responses for each question were analyzed to identify the comparative impact of each assessed demographic characteristic on key metrics including respondents' perceptions of their own attitudes, beliefs and predicted actions, respondents' perceptions of others' attitudes, beliefs and actions and respondents' perceptions of ideal attitudes, beliefs and actions.

To evaluate the results of the survey, the implications of the responses to each of these three questions is considered. Through their choices, a respondent may indicate that they believe that their own behavior needs to change—either that they use a metric more than what is ideal or less than what is ideal. A respondent may additionally express that the behavior of others should change to either use a particular metric more or less than they currently do. When these beliefs are not common between self-perception and the perception of others, the respondent may either believe themselves to be better or worse than other people in their use of that metric. These paradigms may indicate different levels of buy-in for possible change. These paradigms are summarized in Table 3.

**Table 3.** Paradigms of survey respondents' beliefs based on the level of self-usage, others' usage, and ideal usage reported for each metric.

When respondents believe that a current status of high matches the ideal, or that self-usage is not ideal and the metric should be used, label mechanisms and educational initiatives may be more likely to achieve buy-in from the public. For example, if respondents believe that they should be more concerned about the sponsors of an article, it is likely that they would be receptive to labeling news media with sponsor information. By contrast, if users indicate that they use a metric too much or the problem (deviation from ideal) is only others' usage levels, this can indicate a potential problem area where usage is not perceived as ideal, but there may be little incentive to change. For example, a problem with only others' usage may mean that most individuals consider themselves to be an exception and not in need of labels' assistance. Using these responses, thus, the categories of labels that could be implemented most immediately with positive reception can be identified. Categories that would not be well received, and those which may require educational support to build public understanding of the metric and how it can be used are also apparent.

For each question, the hypothesis that a logical correlation between the demographic characteristic and responses being measured existed was tested against a null hypothesis of no correlation existing. Each hypothesis was based on a particular type of information about the article, such as it's the identity of its creator, publisher or sponsors. The characteristics which were selected were based on their availability to news article consumers for decisionmaking and were selected as part of a prior study [62].

The data from each metric for each demographic are presented in Sections 4 and 5 and trends present in the data are assessed. In this trend analysis, a positive correlation means that the metric increased along with an increase in the demographic (e.g., more support with older age) and a negative correlation means that the metric decreases with an increase in the demographic (e.g., less support with older age). Qualifiers such as 'minimal' are used to indicate the magnitude of the trend and thus identify trends that may exist but not have practical significance.

#### **4. Analysis of the Impact of Article Title, Author, Publisher and Metadata on Perceptions of Content Trustworthiness**

This section analyzes the impact of several article characteristics and metadata elements on Americans' perception of content trustworthiness. These perceptions are integral to decisions that Americans make when consuming and otherwise using (e.g., posting or sharing) news content.

### *4.1. Article Title*

The assessment in this section begins with article titles. The article title is, arguably, the most prominent feature of many articles (a lead picture may be more prominent in some cases). It tells the prospective reader what they may be reading about, should they choose to read the article, and is typically one of the first things the reader sees about the article—in many cases, seeing the title on a page that links to the actual article.

Given this, respondents were asked about the impact of an article's title on their perceptions of its trustworthiness. This data is shown in Appendix A in Figure A1. The vast majority of respondents felt that it was important, with a minimal number of respondents indicating that it had no impact at all. The impact of the title is the greatest for the 40–44 age group. The 18–24, 25–29 and 30–34 age groups also show high interest in this aspect of the article, with over 50% of respondents in these three groups indicating that they place a "great deal" or "a lot" of importance on this characteristic.

The impact of the article's title shows a negative correlation with educational level. Excepting a small resurgence for master's degree holders, the number of individuals indicating that it matters "a great deal" declines steadily with additional education. The pattern, when considering the "a lot" responses is less clear, with this second group reaching a similar level (when combined with the "great deal" responses across educational levels).

The impact of gender on the article title's impact on perceptions of trustworthiness is minimal. Male and female respondents both indicated placing "a great deal" and "a lot" of focus on the title with similar frequency. Males were more likely to place no weight on the title altogether, while females were more likely to place "a moderate amount" of focus on it than males.

Respondents were also asked how they believed the title impacted the trustworthiness perceptions of others. A demonstrable trend again exists between the 18–24 age groups and the 50–59 age groups with the number of respondents indicating "a great deal" consistently falling (with a slight resurgence in the 30–34 age group) throughout this range. This general trend, albeit with more fluctuations, also exists for the combined number of "great deal" and "a lot" respondents.

Comparing the results from Figures A1a and A2a, it is notable that, in most cases, more individuals indicated that others give "a great deal" of focus to the title than said that they themselves did. In all instances but one, the 25–29 age group, more individuals indicated that others gave either "a great deal" or "a lot" of focus to the title than indicated that they themselves did.

The educational level data, presented in Figure A2b, shows a minor trend amongst the some high school, completed high school and some college levels, with growth in the number of individuals indicating that others place both "a great deal" and "a lot" of focus on the title. Beyond this, there is a notable decline.

Comparing the self-perception and the perception of others, at most levels more respondents indicated that others placed either "a great deal" or "a lot' of focus on the title than they did themselves, with some exceptions. For example, the some high school level had nearly three times as many respondents indicating that they placed "a great deal" of focus on the title themselves, as opposed to others. Generally, though, respondents indicated that others paid more focus to the title than they themselves did.

Like with respondents' self-perceptions, there is minimal difference between male and female respondents regarding the level of focus others placed on the article title.

Respondents were asked what the ideal level of focus to place on the title would be. These results are presented in Figure A3. Notably, there is a very different trend present with this data than either the self-focus or perceptions of others' focus. The age group data shows (with the exception of the 35–39 age group) a gradual incline, up to the exception at the 35–39 level, and then a decline for the combined "great deal" and "a lot" responses. This is notably different than the trends visible in either Figure A1a or Figure A2a.

At many of the levels, more respondents indicated self-belief (considering "great deal" and "a lot" responses) in the title's importance than indicated it ideally being important. In all age groups except one (55–59), more respondents indicated others having a "great deal" or "a lot" of focus on the title than ideally would. The level of difference was particularly pronounced in the 18–24 age group, where 25% more respondents indicated others having focus on this (at the "great deal" or "a lot" levels) than ideally would.

No clear pattern is present between ideal title focus and educational level. There is also not a clear pattern between self-perception and ideal perception, with three educational levels having more self-perception than ideal, two having similar levels and two having less self than ideal perception of the importance of the article title. There is also minimal difference between male and females, with regards to ideal levels of focus on article title.

#### *4.2. Article Publisher*

The next characteristic assessed was the importance of the article's publisher. This data is presented in Figures A4–A6. In terms of age-related data, there is a notable drop in the level of importance of the publisher at the "great deal" level between the 18–24 and 35–39 age groups. It is also present in the combined "great deal" and "a lot" levels between the 18–24 and 30–34 age groups.

Comparing this to the data in Figure A4b is of particular interest as there is a demonstrable increase, at both the "great deal" and combined "great deal" and "a lot" levels between the some high school, high school completion and some college levels. This is the opposite of what might be expected, based on the age-related data. Of course, these levels also include individuals who reached that status sometime ago and are now older. Thus, these two trends—when juxtaposed—are of interest as they show that the age-associated trend is not attributable to education but instead to other factors and (similarly) that the education level-associated trend is not age-attributable but instead attributable to other factors.

While the gender data, in previous figures, has shown minimal difference, Figure A4c shows a notable difference between the two genders. While the "great deal" level is similar, males' "a lot" level is notably higher (40% as opposed to 30%). Thus, males seem to place more weight on the publisher of an article than females. Females also indicated no focus on the article publisher approximately twice as often as males.

Data regarding the respondents' perceptions of the importance that others place on the article's publisher is presented in Figure A5. No obvious trends are present in the age group data. The education level data shows a notable increase in publisher importance between the some high school, high school complete and some college respondents at both the "great deal" and "a lot" levels. This mirrors the trend shown in the self-perception data. The gender data shows that males have a perception of others' importance of the publisher of an article that is similar to the importance they place on it themselves. More males indicated a "great deal" and "a lot" of importance than females. There are, also again, about twice as many females indicating attributing no importance to an article's publisher, as compared to males.

Next, the respondents indicated the ideal level of focus to place on the publisher of an article. The decrease in focus with increasing age at the youngest age levels, that was present in the self-perception data, was also present in the ideal data, with a notable decrease in importance between the 18–24 and 30–34 levels, at both the "great deal" and "a lot" levels.

Comparing Figures A4a, A5a and A6a, it is notable that, in most cases, respondents feel that they and others are placing too much focus on the publisher. More respondents indicated placing personal focus at the "great deal" and "a lot" levels on the publisher than indicated these levels of ideal focus in seven of the ten age groups. Similarly, more respondents indicated believing others focused on the publisher, at the "great deal" and "a lot" levels, then indicated this as being ideal. Again, seven of the ten age groups indicated more focus than ideal.

### *4.3. Publication Date*

Next, focus turns to the publication date of the article. Data related to the level of focus paid to the publication date is presented in Figures A7–A9. A trend of declining importance being placed on the publication date with advancing age is present in the youngest age groups and starting at the 25–29 age group and continuing through the 65 and older group.

Looking at the education level data, there is a notable increase between the some high school and bachelor's degree focus at the combined "great deal" and "a lot" levels. The most educated individuals (master's and doctoral degree holders), though, placed less importance on the publication date (but not as little as the some high school group).

Comparing the genders, males tend to place less importance on the publication date than females, with more females reporting placing a "great deal" or "a lot" of importance on the publication date than males.

With regards to the perceptions of respondents regarding others' perceived importance of the publication date, what is perhaps most notable (in Figure A8a) is the significant fluctuation between age groups. While gradual shifts and trends were present in the self-perception data, the perception of others data lacks a notable trend at the "great deal" and "a lot" levels. There is not a notable pattern between the self-perception and others-perception data.

Comparing the self-perception and others-perception data by educational level finds similarities. The four middle education levels all have a similar level of perception of others' publication date importance to each other. They also are similar to the reported levels of self-importance, both at the "great deal" and "a lot" combined level. Both the self- and others-perception data also show a decline in perceived importance at the master's and doctoral degree levels at the "great deal" and "a lot" combined level. The some high school group is notably different, with no respondents reporting a "great deal" of importance to others, but having more "a lot" of importance responses than the combined "great deal" and "a lot" for the self-perception question.

Finally, the gender data shows more interest in the publication date at the combined "a lot" and "great deal" and combined "a lot", "great deal" and "moderate" levels, despite being similar at the "great deal" alone level. Similar to the self-perception data, it appears that females also perceive the publication date as being more important to others than males do.

In the perceived ideal levels of focus on the publication date of the article (shown in Figure A9), a general decline in importance is seen from the 25–29 age group and older at the combined "great deal" and "a lot" levels. This trend is similar to the decline in importance of the publication date seen in the self-importance and others-importance data presented in Figures A7a and A8a.

Similar trends are also present in the educational level and gender data. A similar level of perceived ideal importance is seen at the middle education levels, with lower importance being placed on the publication date by the some high school level and masters and doctoral degree holders. Females also place more importance on the publication date, mirroring the self- and others-importance data.

#### *4.4. Article Author*

Focus now turns to the perceived importance of the article's author. Data regarding this is presented in Figures A10–A12. The youngest age groups place the highest weight on the author. The 18–24 to 30–34 age groups have the highest levels of "great deal" and "a lot" responses (though the 40–44 age group has more combined "great deal" and "a lot" but not "great deal" responses alone). A related trend exists of giving more weight to authors at higher educational levels. This trend is present throughout all educational levels, with limited fluctuation, for "great deal" responses and up to the master's level for the combined "great deal" and "a lot" levels. No major differences are notable in the gender data.

The data in Figure A11 depicts respondents perception of others' focus on the importance of articles' authors. Few patterns in this data are notable. The age level data shows fluctuation and no clear trends. The education-level data largely mirrors the self-perception data. Interestingly, associate's degree holders reported higher concern for an article's author than those that have completed high school and those with some college completed and bachelor's degrees; however, they reported others having less interest in it. Like the self-perception data, females had less "a lot" responses and more "moderate" responses for others-perception and a slightly higher level of reporting no focus on the article's author.

Figure A12 presents respondents' perception of the ideal level of focus to place on articles' authors in assessing their trustworthiness. The age group data shows a gradual rise in the combined "great deal" and "a lot" responses from the 18–24 to 55–59 age groups. Notably, the inverse of this pattern appears to be present in the "great deal" responses, meaning that the middle age groups have the highest "a lot" levels while the younger and older age groups have the highest "great deal" levels (40–44 is an exception to this).

A similar pattern exists with regards to the educational level data, with a gradual rise and then fall. Notably, the two ends (some high school and doctorate holders) both have no individuals giving no focus to the author and thus have the highest combined "great deal"/"a lot"/"moderate"/"little" combined responses. They both also have the highest "great deal"/"a lot"/"moderate" response levels. No notable differences are present in the gender data.

## *4.5. Article Sponsors*

Next, focus turns to the impact of article sponsors on respondents' perception of article trustworthiness and credibility. Figures A13–A15 present data related to this topic.

In assessing the age range data, no clear pattern or trends are present. In assessing the educational level data, there is a general growing weight given to articles' sponsors with increasing educational level, for the "great deal" and "a lot" levels, starting at the some high school educational level and reaching the master's degree level. This trend is also present with the combined "great deal", "a lot" and "moderate" response levels through all educational levels. The gender data is relatively close to parity.

Figure A14 shows respondents' perception of the weight that others place on the article sponsor. Similar to the self-perception data, the others-perception data shows no clear pattern related to age groups. The pattern of growing interest in article sponsors with advanced education level is apparent at both the combined "great deal" and "a lot" level and the combined "great deal" / "a lot" / "moderate" level. Only slight differences again exist between the male and female respondents, in Figure A14c.

Finally, Figure A15 presents respondents' perception of the ideal level of focus to place on article sponsors. Again, no clear pattern exists in the age group data. The pattern of growing interest with advanced education is again present and most notable at the combined "great deal" and "a lot" level. Once again, the genders are close to parity.

#### *4.6. Author's Political Alignment*

Now, focus turns to the impact of the author's political alignment on respondents' perception of article credibility. Data related to this topic is presented in Figures A16–A18.

Figure A16a shows a general trend where the level of weight placed on the author's political alignment increases from the 18–24 age group, peaking at the 40–44 age group, before declining until the 55–59 age group, for the combined "great deal" and "a lot" levels. It climbs again at the 60–64 and 64 and older groups. A trend of growth in focus with higher education level is shown between the some high school and master's degree levels for the combined "great deal" and "lot levels". The doctorate holders have a lower level of focus than the master's degree holders. Males also, notably, give more credence to the author's political alignment than females.

Figure A17 shows respondents' perceptions of others' focus on the author of an article's political alignment. The age series data shows two general upward growth trends in the combined "great deal" and "lot data". The first trend starts in the 18–24 age group and ends at 44. The second starts in the 45–49 age group and continues to the 65 and older group, with a demonstrable drop between the 40–44 and 45–49 age groups. The educational level trend present in the self-perception data is also present in the others-perception data, in the combined "great deal" and "a lot" level data, with growth from the some high school level up through the doctorate holder levels. In the gender data, the greater self-perception of males' focus on authors' political alignment has a corresponding believed greater focus of others, at the "great deal" and "a lot" levels. However, the gender difference is corrected in the "moderate" level and the two genders have similar "little" and "none" response levels.

Figure A18 presents respondents' perspectives of the ideal level of focus to pay to articles' authors' political alignment. Two growth trends, with a decline between them, are present. A less pronounced trend is also present of growing ideal focus on authors' political affiliations with increasing educational level, from the some high school educational level up until the master's degree level. There is marginally more ideal focus on author's political affiliations amongst males at the combined "great deal" and "a lot" level; however, the "moderate" level has slightly less male responses and the "little" and "none" levels are the same for both genders.

#### *4.7. Publisher's Political Alignment*

Next, the perception of the publisher's political alignment's impact on article trustworthiness is considered. Figures A19–A21 present data related to this topic.

Figure A19a shows two growth trends, where older age correlates with more focus on publisher's political alignment. A growth trend is also present, associated with increasing educational level. It starts at the some high school level and continues up to the master's degree level for the "great deal" and "a lot" levels. There is also a notably higher level of focus on article publishers' political alignment amongst male respondents at all levels.

Figure A20 presents respondents' beliefs about the level of focus that others place on article publishers' political alignment. Here, only a trend between the 55–59 and 65 and above age groups is notable. A trend of increasing focus is present in the educational level data from the some high school level to master's degree level. Doctoral degree holders have a notably lower level of focus than master's level respondents (and the second lowest overall). Finally, the greater focus amongst males self-perception is also present amongst males perceptions of other's focus on article publishers' political alignment; however, it is not as pronounced of a difference.

Figure A21 presents respondents' perspectives regarding the ideal level of focus to place on the publisher's political alignment. No clear trend is present in the age group data. A less pronounced version of the education level-associated trend is present. It is notable that, across most educational attainment levels for the "great deal" and "a lot" of focus levels, the ideal level of focus is less than the focus reported for self-perception and others-perception, with two exceptions. Notably, more focus is desired by the some high school group and the doctorate holders group has approximately same level of focus as

ideal in both their self- and others-perception responses. Finally, the gender data shows that more males than females see a "great deal" of focus as ideal. However, the difference becomes less notable at lower levels of concern.

#### *4.8. Sponsor's Political Alginment*

Focus now turns to the impact of articles' sponsors' political alignment. Data related to this topic is presented in Figures A22–A24.

The age group data presented in Figure A22a shows no clear trends. The educational level data shows a general increase in the level of focus placed on articles' sponsors' political alignment along with education level, from some high school to doctoral degree holders at the combined "great deal" and "a lot" levels. The gender-based data shows a greater focus among male respondents on articles' sponsors' political alignment, as compared to female respondents.

Figure A23 presents the respondents' beliefs regarding others' perspectives as to the importance of articles' sponsors' political alignment in assessing article trustworthiness. Like with the self-perspective data, no clear trends are present in the age group data. There is a positive correlation between higher levels of education and additional focus on articles' sponsors' political alignment. There is, also similarly, a greater level of focus on articles' sponsors' political alignment attributed to others by male respondents.

Figure A24 presents what respondents believe to be the ideal level of impact of articles' sponsors' political alignment on perceptions of article trustworthiness. Like with the selfperception and others-perception data, no clear trends are present in the age group data. There is a similar trend of a positive correlation between higher level of education and higher ideal levels of focus on articles' sponsors' political alignment. The trend of males having more focus on articles' sponsors' political alignment is also present in the ideal data.

#### **5. Analysis of the Impact of Article Characteristics on Perceptions of Content Trustworthiness**

This section analyzes the impact of four article characteristics on Americans' perceptions of online article trustworthiness. The impact of the quantity of opinion statements, article virality, article controversy level and article reading level are considered.

#### *5.1. Opinion Statement Quantity*

In analyzing the data regarding opinion quantity (in Figure A25a), no clear patterns are visible. Conversely, the education level analysis shows much less variability and a slight positive correlation between additional education and focus on opinion statements when assessing content trustworthiness. Figure A25c shows that there is slightly more interest amongst females, than males, in the quantity of opinion statements when assessing trustworthiness.

Figure A26 presents Americans' perceptions of others' focus on the quantity of opinion statements in an article when assessing its credibility. A small downward trend is visible in the age group data, albeit with fluctuations, where older age groups are less concerned about the quantity of opinion statements than those in younger groups. No significant trends are notable in the education associated data. There is also no pronounced difference in males versus females.

Figure A27 presents data regarding what Americans think the ideal level of focus on the number of opinion statements in an article should be for assessing article credibility. Again, in the age group data, no clear pattern is present. In comparing Figures A25a, A26a and A27a, the age groups have appreciable correlation across the three types of responses. The correlation (being higher or lower, as compared to adjacent groups) is present across most levels for the self-perception and others-perception data. However, it is only prevalent across the higher age groups, when comparing the self- and others-perception data to the ideal-perception data.

There is, again, no notable trend across educational levels for the ideal data. The ideal level of focus on opinion statements, across educational levels, seems to be closer to the self-perception than the others-perception data. Notably, many age groups indicate more others-perception than ideal perception. Finally, the differences between the genders are minimal, with slightly more females using opinion statement quantity when assessing news trustworthiness.


**3.3. Medial input/output variables: The medial outputs of phase I and also the medial inputs of phase II**

### **3.4. Output variables**

Phase II Output Variables in: The results of recent studies have contributed to energy effi‐ ciency or environment efficiency evaluation problems that consider total production activity factors. Ramanathan [53] proposed an overall efficiency index that combined energy inputs, desirable outputs and undesirable outputs using DEA to study the relationships among global GDP, energy consumption, and carbon dioxide emissions. The final outputs used in this research, are as follows:

**Input Variables (Phase I)**

3. Generating Capacity Dorian, 1998; Morey, 2001; Dugan et al., 2002

4. Operation Expenses Kannan and Pillai, 2000; Herman, 2002; AMEC, 2004

**Medial Input/Output Variables (Output Phase I and Input Phase II)**

3. CHP IEA; Renewable Information, 2011

1. TEPS/GDP ratio PPPs (www.OECD-iLibrary.org)

2. TEPS/Population ratio Renewable Information, 2011; PPPs

Note. Source from this study

**3.6. DEA model**

**Table 1.** Input and Output Variables

3. Grid Halcrow, 2005; Bedard et al., 2005

Data Envelopment Analysis (DEA) is a method for measuring the performance efficiency of decision units, characterizing by multiple input and output variables [8]. The DEA techni‐ que uses linear programming to estimate the maximum potential efficiency for various lev‐ els of inputs based on each firm's actual inputs and output. DEA includes two major models, the CCR model, and the BCC model. Charnes, Cooper and Rhodes [54] proposed a model under the assumption of constant return to scale (CRS), called the CCR model. This model is only appropriate when all DMUs are operating at an optimal scale. Banker, Charnes and Cooper [55] extended the CCR model to include the variable returns to scale named the BCC model, which can further decompose the TE into two components: pure technical efficiency (PTE) and scale efficiency (SE). The problem of calculating efficiency can

be formulated as a fractional linear programming problem as below:

**Output Variables (Phase II)**

1. Fuel IEA; Glaser, 1977; Thorpe, 1999; Boud and Thorpe, 2003; Schneider and

Comparative Analysis of Endowments Effect Renewable Energy Efficiency Among OECD Countries

2. Labor Buonafina, 1992; Adjaye, 2000; Morey, 2001; Ghosh, 2002; Dugan et al.,

1. EOP Olatubi and Dismukes, 2000; Lam and Shiu, 2001; Nag, 2006; Pombo and

2. HOP Agrell and Bogetoft, 2004; Renewables Information, 2011

McCarl, 2003;Owen, 2004; Bedard et al., 2005; Previsic et al., 2005; Dowaki and Mori, 2005; Caputo et al., 2005

http://dx.doi.org/10.5772/52020

201

2002;

Taborda, 2006; Sueyoshi and Goto, 2010; Renewables Information, 2011

We used the intermediation approach to view the energy industry as intermediaries, and summarized the major input and output variables in Table 1.

#### **3.5. Research resource and sample**

This research is based on DEA of operating procedures. Though data collection and litera‐ ture review on performance measurement of renewable power, we can understand the dif‐ ferences in renewable energy efficiency among 34 OECD countries (Table 2) and provide suggestions for Taiwan. The data obtained for this analysis were gathered from many rele‐ vant data resources, including the IEA, Renewable Information, World Bank, and other en‐ ergy indices of a representative sample from 2007 to 2009. However, the data obtained from Renewable Energy Information [48] are used account for the full range of statistics collected from the Annual Renewables and Waste Questionnaire. This database of annual statistics for OECD countries covers hydroelectricity, solid biofuels, geothermal, renewable municipal waste, wind, gas from biomass, liquid biofuels, solar photovoltaic, solar thermal, tide/wave/ ocean, non-renewable municipal waste and industrial waste. It includes EOP and HOP from renewable sources and supply/demand balances of renewable and waste products. The pri‐ mary data from this system are from IEA annual publications.

**Table 1.** Input and Output Variables


3. A comprehensive approach for engaging society

reduce PBRPs with difficult access [28], for example, encouraging architects to eliminate open gutters that are hard to access [29]. However, the inevitable existence of those PBRPs almost ubiquitously demand interventions that are applied in a "diffuse way", such as "peri-focal" interventions with residual insecticides [1], release of sterile adult mosquitoes or strategies

The Mosquito Drain is based on the idea of attracting females to ubiquitous oviposition places where larvae can be eliminated (e.g. domestic breeding traps, see Box 1) rather than natural, but inaccessible sites thereby eliminating the next generation of mosquitoes.

In an urban environment, some breeding and resting sites are likely to be inaccessible for cleaning and control (e.g., roofs, crevices, tree holes, etc.; Figure 1). However, not all potential breeding places are equally attractive to laying mosquitoes and "compete" for females' preference. Removal of accessible breeding sites would have the following

2. impel females to over-disperse [30, 31] (so infected mosquitoes will cover an area

3. reduce the quality of potential breeding places sought by females (potential reduc-

Because "egg-laying females were most attracted to sites containing other immature Aedes, rather than to sites containing the most food" [9], home traps could become especially attractive to gravid females, and therefore be disproportionally important in reducing the mosquito population. Alternatively, attractants can be added to encourage mosquitoes to preferentially use lethal ovitraps that can be managed or left to biodegrade rather than inaccessible natural PBRPs [32–34]. The Mosquito Drain posits that it is not necessary to eliminate all breeding sites to cause the population to crash, which would not be practicable anyway, but that by (i) removing manageable breeding sites (e.g. putting lids on water containers), (ii) providing alternative attractive breeding sites that are easily managed (e.g. 'lure' breeding adults with a suitable trap) and that (iii) kill future generations of mosquitoes (e.g. adding larvicide to ovitraps) would eliminate sufficient reproductive capability of the mosquito population as to drive the population to extinction or at least pushing the biting population below levels at which virus

This is a societal effort that depends on collaboration between (many) individuals and government agencies: individuals would be in charge of eliminating any larvae, pupae and/or eggs that could have been accumulated in domestic breeding places (like plant pots and fountains) whilst governments should broadcast a reminder and coordinate that effort. Government agencies would then be freed to tackle hard to access and public spaces.

involving multiple traps ("Mosquito Drain"; Box 2).

84 Dengue Fever - a Resilient Threat in the Face of Innovation

effects on female mosquitoes in search for oviposition sites:

tion -but not elimination- of viable broods).

1. impel females to search for alternative potential breeding places;

Box 2. Mosquito drain.

quicker)

circulation is sustained.

Mosquito control depends on human actions, yet those actions are often at the mercy of legal and physical constraints. Dissecting the legal and physical complexity of contemporary urban ecosystems results in a categorization that can assist the effective implementation of interventions. These categories – based on the diversity of putative oviposition and resting sites – can be easily integrated into existing habitat management behaviors, and can be readily integrated into GIS mapping technologies to generate actionable information to tackle endemic infestations and unfolding outbreaks [29, 38].

One principle reason for successful control in the past century was the implementation of aggressive top-down measures [8, 12, 39]. The erosion of governmental capabilities to interfere with individual liberties does not necessarily impede mosquito control, as that "loss" may be compensated by an increasingly technologically-savvy, knowledge-avid and social media linked population can be mobilized to combat mosquito populations [40–42]. The proposed framework assumes that it is possible to effectively engage the local population [7], not only by suppressing areas of infection where they can easily act (e.g. their properties), but also by collaborating in a forcing a "Mosquito Drain" (Box 2) to reach beyond their immediate domain of direct impact.

Prioritizing citizens' actions has several potential benefits: (a) reduced strain on limited public resources that are stretched during public health crises (e.g. epidemics); (b) individuals can act on more targeted and sustained activities [43]; (c) reduction of harmful interventions (e.g. use of fogging in urban spaces that can be practically managed by community initiatives). The local population is also most likely to recognize hotspots of mosquitoes [41, 44, 45] and appreciate local conditions of epidemiological importance [18]. Although evidence for effectiveness of individual community-based interventions is sparse [37], it appears that integrating community participation into schemes reduces costs and increases effectiveness [46–48].

and regular reminders [39, 51]–for example to clean out water containers, mosquito traps or remove refuse each week [17]. Over reliance on past success risks mosquito populations rebounding, for example because surveillance priorities shift and vigilance suffers [35].

Urban Ecology and the Effectiveness of *Aedes* Control http://dx.doi.org/10.5772/intechopen.78688 87

The key challenge in community participation is sustaining interest. As an example of citizen engagement in action, in two Cuban cities house blocks were randomly enrolled in a trial to control PBRPs (2000–2002), resulting in 75% reduction in Aedes populations through adding lids to water containers (i.e. monitoring accessible and accountable), repairing drains and transforming areas of garbage into (maintained) flowerbeds (i.e. accessible but not necessarily accountable) [53]. Importantly, these neighborhood task forces were still in operation 5 years later when there was an outbreak of dengue and proved cost and health effective [43, 47, 48]. However this sustainability may be unusual with evidence from other studies suggest that success may lead to changes in focus that risk lapses in effort [35], volunteers lose enthusiasm [22] and that adherence to control measures diminishes over time (though still out-perform no activity) [54, 55], more so if initiatives (and official cajoling) end [21]. Evidence of citizen science mosquito surveillance suggests good initial participation that rapidly decreased [41], and the few studies that evaluate the effectiveness of community interventions, whilst generally positive for vector control, lasted a year of less [55, 56]. Encouraging appropriate community participation in control measures is likely to be easier in the midst of epidemics when the benefits are visible, but it remains unclear whether this is sustainable in the longer-term in between episodes of, for example, dengue. That is why it is so important that control measures

are "cross-cutting" within the context of a community, as we will see below.

livability

unavailable, disrupted or fails.

4. Transforming cities in a large mosquito trap while improving their

depressed or unplanned urban areas, thereby improving living conditions [59–61].

Aedes-transmitted diseases are, largely, diseases emanating from neglected private and social spaces [57]. In backyards, buildings, vacant lands and empty lots, trash and untended structures provide perfect breeding places not only for Aedes mosquitoes, but also for many other urban and domestic pests. These neglected places have a negative impact on the environment and quality of life of the community, as well as on their economic development and safety [58]. Therefore, a campaign to remove mosquito breeding places is also a campaign to reinvigorate

It is important to highlight that mosquito control has to be integrated into "cross-cutting" solutions for public health, turning societal vulnerabilities into resilience [61, 62] – i.e. what is good for elimination of Aedes, should also be beneficial on other societal fronts. For instance, environmental management of Aedes might discourage traditional ad hoc water storage practices such as private water-storage systems [16, 28]. But resilience to crises and catastrophes are enhanced through decentralized and resource-autonomous societies [63], for example potable water that is locally collected, treated [64] and appropriately stored (so that it is inaccessible to mosquitoes) would still be available even if the water supply from a centralized provider is

Engaging populations need not be costly (in time or money) given new communication technologies [40] (Figure 3) and, by stimulating and coordinating positive bottom-up initiatives, health agencies can co-opt allies in collective health emergencies [49]. In contrast, topdown approaches to combat Aedes risk treating citizens like irresponsible actors (for example threatening fines [35, 39]) fail to realize the emergent benefits of community participation. Emphasizing the power of bottom-up initiatives is not meant to marginalize the role of topdown activities [7, 8, 12]: as shown in our categorization (Figure 1), even the most engaged community will not be able to manage all putative mosquitoes breeding sites. Public authorities have an immense role to play, but are perhaps more efficient exercising their mandate in the expensive activities of avoiding a state of neglect in public spaces that risks them becoming the foci of urban pests and then efficiently using a smaller budget to encourage and support societal initiatives (e.g. nudging behavioral change [52]) to address readily accessible environments that would otherwise rapidly drain central resources.

The challenge is also to effectively manage activities, whether top-down or bottom-up that risk being popular, but ill conceived. The WHO emphasizes detailed planning to achieve successful behavioral change and recommend a series of steps to capitalize on public engagement to avoid what they consider the two greatest barriers of doing nothing or, perhaps worse, doing the wrong thing (hence putting people off further interventions if their efforts fail) [50]. In addition to combating lack of knowledge or misinformation, governmental activities need to manage social engagement campaigns beyond planning and into co-ordination since such campaigns to change behaviors have been most successful when combined with feedback

Figure 3. Interface from a citizen-science mosquito identification and reporting application used in Spain to assist in the surveillance efforts. Provided by mosquito alert CC-BY [41].

and regular reminders [39, 51]–for example to clean out water containers, mosquito traps or remove refuse each week [17]. Over reliance on past success risks mosquito populations rebounding, for example because surveillance priorities shift and vigilance suffers [35].

Prioritizing citizens' actions has several potential benefits: (a) reduced strain on limited public resources that are stretched during public health crises (e.g. epidemics); (b) individuals can act on more targeted and sustained activities [43]; (c) reduction of harmful interventions (e.g. use of fogging in urban spaces that can be practically managed by community initiatives). The local population is also most likely to recognize hotspots of mosquitoes [41, 44, 45] and appreciate local conditions of epidemiological importance [18]. Although evidence for effectiveness of individual community-based interventions is sparse [37], it appears that integrating community participation into schemes reduces costs and increases effectiveness [46–48].

Engaging populations need not be costly (in time or money) given new communication technologies [40] (Figure 3) and, by stimulating and coordinating positive bottom-up initiatives, health agencies can co-opt allies in collective health emergencies [49]. In contrast, topdown approaches to combat Aedes risk treating citizens like irresponsible actors (for example threatening fines [35, 39]) fail to realize the emergent benefits of community participation. Emphasizing the power of bottom-up initiatives is not meant to marginalize the role of topdown activities [7, 8, 12]: as shown in our categorization (Figure 1), even the most engaged community will not be able to manage all putative mosquitoes breeding sites. Public authorities have an immense role to play, but are perhaps more efficient exercising their mandate in the expensive activities of avoiding a state of neglect in public spaces that risks them becoming the foci of urban pests and then efficiently using a smaller budget to encourage and support societal initiatives (e.g. nudging behavioral change [52]) to address readily accessible environ-

The challenge is also to effectively manage activities, whether top-down or bottom-up that risk being popular, but ill conceived. The WHO emphasizes detailed planning to achieve successful behavioral change and recommend a series of steps to capitalize on public engagement to avoid what they consider the two greatest barriers of doing nothing or, perhaps worse, doing the wrong thing (hence putting people off further interventions if their efforts fail) [50]. In addition to combating lack of knowledge or misinformation, governmental activities need to manage social engagement campaigns beyond planning and into co-ordination since such campaigns to change behaviors have been most successful when combined with feedback

Figure 3. Interface from a citizen-science mosquito identification and reporting application used in Spain to assist in the

ments that would otherwise rapidly drain central resources.

86 Dengue Fever - a Resilient Threat in the Face of Innovation

surveillance efforts. Provided by mosquito alert CC-BY [41].

The key challenge in community participation is sustaining interest. As an example of citizen engagement in action, in two Cuban cities house blocks were randomly enrolled in a trial to control PBRPs (2000–2002), resulting in 75% reduction in Aedes populations through adding lids to water containers (i.e. monitoring accessible and accountable), repairing drains and transforming areas of garbage into (maintained) flowerbeds (i.e. accessible but not necessarily accountable) [53]. Importantly, these neighborhood task forces were still in operation 5 years later when there was an outbreak of dengue and proved cost and health effective [43, 47, 48]. However this sustainability may be unusual with evidence from other studies suggest that success may lead to changes in focus that risk lapses in effort [35], volunteers lose enthusiasm [22] and that adherence to control measures diminishes over time (though still out-perform no activity) [54, 55], more so if initiatives (and official cajoling) end [21]. Evidence of citizen science mosquito surveillance suggests good initial participation that rapidly decreased [41], and the few studies that evaluate the effectiveness of community interventions, whilst generally positive for vector control, lasted a year of less [55, 56]. Encouraging appropriate community participation in control measures is likely to be easier in the midst of epidemics when the benefits are visible, but it remains unclear whether this is sustainable in the longer-term in between episodes of, for example, dengue. That is why it is so important that control measures are "cross-cutting" within the context of a community, as we will see below.


*Article* **Optimization of the Parameters Influencing the Antioxidant Activity and Concentration of Anthocyanins Extracted from Red Onion Skins Using a Central Composite Design**

**Florina Stoica, Oana Emilia Constantin, Nicoleta Stănciuc, Iuliana Aprodu, Gabriela Elena Bahrim and Gabriela Râpeanu \***

> Integrated Center for Research, Expertise and Technological Transfer in Food Industry, Food Science, Food Engineering, Biotechnology and Aquaculture Department, Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, 111 Domnească Street, 800201 Galati, Romania **\*** Correspondence<EMAIL_ADDRESS>Tel.: +40-0336-130-177

**Abstract:** This study aimed to extract bioactives from red onion skins for use as edible colorants that are both natural and functional. The extraction of bioactive chemicals from red onion skins using a conventional solvent extraction was optimized using a Central Composite Design (CCD). The influence of extraction parameters, such as ethanol and citric acid concentrations, extraction temperature, and time, on anthocyanin content and antioxidant activity (DPPH method) was studied. A quadratic model was suggested for all of the parameters examined and employed. Citric acid concentration (0.05–2.64%), ethanol concentration (6.36–73.63%), operation temperature (16.47–58.52 ◦C), and extraction duration (10–234.54 min) were the variables studied in the coded form of the experimental plan. The best conditions for maximum anthocyanins and antioxidant activity recovery were: 60% ethanol, 0.87% citric acid, 179.99 min, and 25 ◦C. The anthocyanins concentration varied from 0.45 to 1.43 mg C3G/g DW, while the antioxidant activity varied from 24.29 to 37.20 mM TE/g DW, according to the experimental design. Overall, it should be emphasized that the extraction process can be enhanced by settling the operating factors to maximize the model responses. The current findings demonstrate that extracts from red onion skins would be useful in developing functional food products.

**Keywords:** anthocyanins; extraction; antioxidant activity; red onion skins; CCD