**6.2 Artificial intelligence-driven segmentation**

To plan multiple trajectories, especially in a percutaneous fashion, multiple organs surrounding the pancreas need to be considered. To obtain a good spatial understanding of the acquired tomographic images, 3D representations from the structures of interest help in the decision-making process. Where time may be sufficiently available in the preoperative phase, it is a valuable asset during the intraoperative phase. Therefore, a compromise between accuracy and processing time must be chosen to enable 3D reconstruction from intraoperative tomographic images. Deep learning-based segmentation has shown its potential in multiple fields including medical imaging tasks [49]. Segmentation of the pancreas is seen as a challenging task due to the dependency on good delineation of the organ to its adjacent structures in the abdominal cavity [50]. To segment the complete range of structure needed for pancreas IRE planning, Roth et al. [51] describe a multi-scale pyramid of 3D fully convolutional network. The reported network was trained and validated using 377 clinical CT datasets with annotated organs and vessels. The performance of the system was measured by means of the DICE score, which represents the similarity between the automatic segmentations from CT images not used for training and their manual annotations. The network was able to achieve a Dice score close to 90% on average, which holds promising aspects for automatic, intraoperative segmentation [51].

### **6.3 Automatic trajectory optimization**

Based on the patient-specific data, automatic trajectories can be computed according to permitted access paths while securing a specific distance to structures at risk [52]. The optimization for the IRE use case would further depend on the needle configuration, interelectrode spacing, and parallelism constraints.


**6. References**

Production of Biodiesel Via In-Situ Supercritical Methanol Transesterification 243

Gaur, R.; Sharma, A.; Khare, S. K. & Gupta, M. N. (2007). A novel process for extraction of

Ghadge, S. V. & Raheman, H. (2005). Biodiesel production from mahua (Madhuca indica) oil having high free fatty acids. *Biomass and Bioenergy*, Vol. 28, pp. 601–605. Han, H.; Cao, W. & Zhang, J. (2005). Preparation of biodiesel from soybean oil using

Harrington, K. J. & Evans, C. D. A. (1985). Transesterification in situ of sunflower seed oil.

Hass, M. J.; Scott, K. M.; Marmer, W. N. & Foglia, T. A. (2004). In situ alkaline

Hawash, S.; Kamal, N.; Zaher, F.; Kenawi, O. & El Dewani, G. (2009). Biodiesel fuel from

He, H.; Wang, T. & Zhu, S. (2007). Continuous production of biodisel fuel from vegetable oil

Heller, J. (1996). *Physic nut. Jatropha curcas L. Promoting the conservation and use of underutilized*

Herrera, J. M.; Siddhuraju, P.; Francis, G., Ortiz.; G. D. V. & Becker, K. (2006). Chemical

Ikwuagwu, O. E.; Ononogbu, I. C. & Njoku, O. U. (2000). Production of biodiesel using

Jiang, L.; Hua, D.; Wang, Z. & Xu, S. (2009). Aqueous enzymatic extraction of peanut oil and protein hydrolysates. *Food and Bioproducts Processing*, Vol. 88 (2-3), pp. 2010. Kansedo, J.; Lee, K. T. & Bhatia, S. (2009). *Cerbera odollam* (sea mango) oil as

Kildiran, G.; Yucel, S. O. & Turkay, S. (1996). In-situ alcoholysis of soybean oil, *Journal of*

King, J. W.; Mohamed, A.; Taylor, S. L.; Mebrahtu, T. & Paul, C. (2001). Supercritical fluid

Kusdiana, D. & Saka, S. (2001). Kinetics of transesterification in rapeseed oil to biodiesel fuel

Kusdiana, D. & Saka, S. (2004). Effects of water on biodiesel fuel production by supercritical

Leung, D. Y. C.; Koo, B. C. P. & Guo, Y. (2006). Degradation of biodiesel under different

as treated in Supercrititcal methanol. *Fuel,* Vol. 80, pp. 693-698.

methanol treatment. *Bioresource Technology*, Vol. 91, pp. 289–295.

storage conditions. *Bioresource Technology*, Vol. 97(2), pp. 250-256.

*American Oil Chemists' Society,* Vol. 73, pp. 225–228.

using supercritical methanol process. *Fuel, Vol.* 86, pp. 442-447.

Gatersleben/ International Plant Genetic Resources Institute, Rome.

*Technology*, Vol. 98(3), pp. 696-699.

3151.

318.

83–89.

88(3), pp. 579-582.

12(1), pp. 57-62.

1148-1150.

241–249.

*Chemistry*, Vol. 96(1), pp. 80–89.

edible oils: Enzyme assisted three phase portioning (EATPP). *Bioresource*

supercritical methanol and Co2 as co-solvent. *Process Biochemistry, Vol.* 40, pp. 3148-

*Industrial & Engineering Chemistry Product Research & Development,* Vol. 62, pp. 314–

transesterification: an effective method for the production of fatty acid esters from vegetable oils, *Journal of American Oil Chemists' Society*, Vol. 81, pp.

*Jatropha* oil via non-catalytic supercritical methanol transesterification. *Fuel*, Vol.

*and neglected crops.* Institute of Plant Genetics and Crop Plant Research,

composition, toxic/antimetabolic constituents, and effects of different treatments on their levels, in four provenances of *Jatropha curcas* L. from Mexico. *Food*

rubber [*Hevea brasiliensis (Kunth. Muell.)*] seed oil. *Industrial Crops and Products*, Vol.

promising non-edible feedstock for biodiesel production. *Fuel*, Vol. 88(6), pp.

extraction of *Vernonia galamensis* seeds. *Industrial Crops and Products,* Vol. 14, pp.

Castro, M. D. L. & Ayuso, L. E. G. (1998). Soxhlet extraction of solid materials: Soxhlet

Chen, W. H.; Chen, C. H.; Chang, C. M. J.; Chiu, Y. H. & Hsiang, D. (2009). Supercritical

Chew, C. S. (2009). *Jatropha curcas.* L.: Development of a new oil crop for biofuel (Summary).

Clark, S. J.; Wagner, L.; Schrock, M. D. & Pinnaar, P. G. (1984). Methyl and ethyl esters as

Darcia, J. L. L. & Castro, M. D. L. (2004). Ultrasound-assisted Soxhlet extraction: An

De, B. K.; Bhattacharyya, D. K. & Bandhu, C. (1999). Enzymatic synthesis of fatty

Demirbas, A. (2003). Biodiesel fuels from vegetable oils via catalytic and non-catalytic

Demirbas, A. (2005). Biodiesel production from vegetable oils via catalytic and non catalytic

Demirbas, A. (2007). Biodiesel from sunflower oil in supercritical methanol with calcium

Demirbas, A. (2008). Studies On cottonseed oil biodiesel prepared in non-catalytic SCF

Diasakou, M.; Louloudi, A. & Papayannakos, N. (1998). Kinetics of the non-catalytic

Eevera, T.; Rajendran, K. & Saradha, S. (2009). Biodiesel production process optimization

Encinar, J. M.; Gonzalez, J. F. & Reinares, A. R. (2005). Biodiesel from Used Frying Oil.

Fernando, S.; Karra, P.; Hernandez, R. & Jha, S. K. (2007). Effect of incompletely converted

Freedman, B.; Pyrde, E. H. & Mounts, T. L. (1984). Variables affecting the yield of fatty esters

Fukuda, H.; Kondo, A. & Noda, H. (2001). Biodiesel fuel production by transesterification of

oils. *Journal of Bioscience and Bioengineering*, Vol. 92(5), pp. 405-416.

and characterization to assess the suitability of the product for varied

Variables Affecting the Yields and Characteristics of the Biodiesel. *Industrial &*

from transesterified vegetable oils. *Journal of American Oil Chemists' Society*, Vol.

oxide. *Energy Conversion and Management*, Vol. 48(3), pp. 937-941.

transesterification of soybean oil. *Fuel*, Vol. 77(12), pp. 1297-1302.

environmental conditions. *Renewable Energy*, Vol. 34(3), pp. 762-765.

conditions. *Bioresource Technology,* Vol. 99(5), pp. 1125-1130.

*Engineering Chemistry Research*, Vol. 44(15), pp. 5491–5499.

soybean oil on biodiesel quality. *Energy*, Vol. 32, pp. 844-851.

future. *Analytica Chimica Acta*, Vol. 369(1-2), pp. 1-10.

*Supercritical Fluids*, Vol. 51, pp. 174–180.

*Convers Mgmt, Vol.* 44, pp. 2093–109.

*Combustion Science, Vol.* 31, pp. 466-487.

pp. 1632–1638.

pp. 451-453.

61(10), pp. 1638–1643.

242.

Institute of Energy Economics, Japan (IEEJ).

extraction of solid materials: anoutdated technique with a promising innovative

carbon dioxide extraction of triglycerides from *Jatropha curcas* L. seeds. *Journal of*

New and Renewable Energy Group, Strategy and Industry Research Unit, The

renewable fuels for diesel engines. *Journal of American Oil Chemists' Society,* Vol. 61,

expeditive approach for solid sample treatment – Application to the extraction of total fat from oleaginous seeds. *Journal of Chromatography A*, Vol. 1034 (1-2), pp. 237-

alcohol esters by alcoholysis. *Journal of American Oil Chemists' Society*, Vol. 76,

supercritical alcohol transesterifications and other methods: a survey. *Energy*

supercritical methanol transesterification methods. *Progress in Energy and*

Production of Biodiesel Via In-Situ Supercritical Methanol Transesterification 245

Rosenthal, A.; Pyle, D. L. & Niranjan, K. (1996). Aqueous and enzymatic processes edible oil

Sahoo, P. K. & Das, L. M. (2009). Process optimization for biodiesel production from

Sahoo, P. K.; Das, L. M.; Babu, M. K. G. & Naik, S. N. (2007). Biodiesel development from

Saka, S. & Kusdiana, D. (2001). Biodiesel fuel from rapeseed oil as prepared in supercritical

Selmi, B. & Thomas, D. (1998). Immobilized lipase-catalyzed ethanolysis of sunflower

Sharma, A. & Gupta, M. N. (2006). Ultrasonic pre-irradiation effect upon aqueous enzymatic

Sinha, S.; Agarwal, A. K. & Garg, S. (2008). Biodiesel development from rice bran oil:

Tan, K. T.; Lee,K. T. & Mohamed, A. R. (2009). Production of FAME by palm oil

Tiwari, A. K.; Kumar, A. & Raheman, H. (2007). Biodiesel production from *Jatropha* oil

Usta, N. (2005). An experimental study on performance and exhaust emissions of a diesel

Varma, M. N. & Madras, G. (2007). Synthesis of biodiesel from castor oil and linseed oil

Veljkovic, V. B.; Lakicevic, S. H.; Stamenkowc, O. S.,;Todorovic, Z. B. & Lazic, M. L. (2006).

Vyas, A. P.; Subrahmanyam, N. & Patel, A. (2009). Production of biodiesel through

Wang, Y.; Ou, S.; Liu, P.; Xue, F. & Tang, S. (2006). Comparison of two different processes to

Warabi, Y.; Kusdiana, D. & Saka, S. (2004). Reactivity of triglycerides and fatty acids

Xin, J.; Imahara, H. & Saka, S. (2008). Oxidation stability of biodiesel fuel as prepared by

content of free fatty acids. *Fuel*, Vol. 85(17-18), pp. 2671-2675.

supercritical methanol. *Fuel*, Vol. 87(10-11), pp. 1807-1813.

*Conversion and Management*, Vol. 49(5), pp. 1248-1257.

*Jatropha*, karanja and *Polanga* oils. *Fuel*, Vol. 88(9), pp. 1588-1594.

402-420.

pp. 691-695.

pp. 529-534.

1–6.

287.

pp. 625-628.

Vol. 252(1-2), pp. 107-112.

Vol. 86(3), pp. 448-454.

Vol. 33(8), pp. 1096-1099.

*Bioenergy*, Vol. 31, pp. 569-575.

*management*, Vol. 46(15-16), pp. 2373-2386.

methanol. *Fuel,* Vol. 80, pp. 225-231.

extraction for edible oil extraction. *Enzyme and Microbial Technology*, Vol. 19, pp.

high acid value polanga seed oil and performance evaluation in a CI engine. *Fuel*,

oil in a solvent-free medium. *Journal of American Oil Chemists' Society,* Vol. 75,

oil extraction from almond and apricot seeds. *Ultrasonics Sonochemistry*, Vol. 13(6),

Transesterification process optimization and fuel characterization*. Energy*

transesterification via supercritical methanol technology. *Biomass and Bioenergy*,

(*Jatropha Curcas)* with high free fatty acids: an optimized process", *Biomass and*

engine fuelled with tobacco seed oil methyl ester. *Energy Conversions and*

in supercritical fluids, *Industrial & Engineering Chemistry Research,* Vol. 46, pp.

Biodiesel production from tobacco (*Nicotianna tabacum* L.) seed oil with a high

transesterification of *Jatropha* oil using KNO3/Al2O3 solid catalyst. *Fuel*, Vol. 88(4),

synthesize biodiesel by waste cooking oil. *Journal of Molecular Catalysis A: Chemical*,

of rapeseed oil in supercritical alcohols. *Bioresource Technology,*Vol. 9, pp. 283-

Lu, H.; Liu, Y.; Yang, Y.; Chen, M. & Liang, B. (2009). Production of biodiesel from

Ma, F.; Clements, L. D. & Hanna, M. A. (1998). The effects of catalysts, free fatty acids and

Machmudah, S.; Kawahito, Y.; Sasaki, M. & Goto, M. (2007). Supercritical CO2 extraction of

Machmudah, S.; Kondo, M.; Sasaki, M.; Goto, M.; Munemasa, J. & Yamagata, M. (2008).

Madras, G.; Kolluru, C. & Kumar, R. (2004). Synthesis of biodiesel in supercritical fluids.

Marinkovic, S. S. &Tomasevic, A. (1998). Transesterification of sunflower oil in situ*. Fuel*,

Meher L. C.; Kulkarni M. G.; Dalai A. K. & Naik, S. N. (2006). Transesterification of karanja

Murugesan, A.; Umarani, C.; Chinnusamy, T. R.; Krishnan, M.; Subramanian, R. &

Naik, M.; Meher, L. C.; Naik, S. N. & Das, L. M. (2008). Production of biodiesel from high

Papamichail, I.; Louli, V. & Magoulas, K. (2000). Supercritical fluid extraction of celery seed

Petchmala, A.; Yujaroen, D.; Shotipruk, A.; Goto, M. & Sasaki, M. (2008). Production methyl

Pradhan, R. C.; Naik, S. N.; Bhatnagar, N. & Swain, S. K. (2008). Moisture-dependent

Qian, J.; Wang, F.; Liu, S. & Yun, Z. (2008). In situ alkaline transesterification of cottonseed

Raheman, H. & Ghadge, S. V. (2007). Performance of compression ignition engine with

Ramadhas, A. S.; Jayaraj, S. & Muraleedharan, C. (2005). Biodiesel production from high

Rashid, U.; Anwar, F. & Knothe, G. (2009). Evaluation of biodiesel obtained from cottonseed

Rathore, V. & Madras, G. (2007). Synthesis of biodiesel from edible and non-edible oils in

supercritical alcohols and enzymatic synthesis in supercritical carbon dioxide. *Fuel,*

mahua (*Madhuca indica*) biodiesel. *Fuel*, Vol. 86(16), pp. 2568-2573.

oil. *Journal of Supercritical Fluids*, Vol. 18, pp. 213–226.

FFA rubber seed oil. *Fuel*, Vol. 84(4), pp. 335-340.

oil. *Fuel Processing Technology*, Vol. 90(9), pp. 1157-1163.

*Agricultural Engineers, Vol.* 41, pp. 1261–1264.

*Supercritical Fluids,* Vol. 41(3), pp. 421–428.

*Fluids*, Vol. 44, pp. 301–307.

*Fuel, Vol.* 83, pp. 2029-2033.

Vol. 77(12), pp. 1389-1391.

825–834.

354-357.

*Technology,* Vol. 108, pp. 389–397.

*Science,* Vol. 35(1), pp. 23-28.

Vol. 99(18), pp. 9009-9012.

Vol. 86, pp. 2650–2659.

*Products*, Vol. 28(2), pp. 155-161.

1096.

*Jatropha curcas* L. oil. *Computers and Chemical Engineering*, Vol. 33 (5), pp. 1091-

water on transesterification of beef tallow. *Transactions of the American Society of*

rosehip seed oil: Fatty acids composition and process optimization. *Journal of*

Pressure effect in supercritical CO2 extraction of plant seeds. *Journal of Supercritical*

(Pongamia pinnata) oil by solid basic catalysts. *European Journal of Lipid Science &*

Neduzchezhain, N. (2009). Production and analysis of bio-diesel from nonedible oils—A review. *Renewable and Sustainable Energy Reviews*, Vol. 13, pp.

free fatty acid Karanja (*Pongamia pinnata*) oil. *Biomass and Bioenergy*, Vol. 32(4), pp.

esters from palm fatty acids in supercritical methanol. Chiang Mai Journal *of*

physical properties of Karanja (*Pongamia pinnata*) kernel. *Industrial Crops and*

oil for production of biodiesel and nontoxic cottonseed meal. *Bioresource Technology*,

**12**

*Thailand*

**Transesterification in Supercritical Conditions**

The transesterification or biodiesel production under supercritical conditions (supercritical transesterification) is a catalyst-free chemical reaction between triglycerides, the major component in vegetable oils and/or animal fats, and low molecular weight alcohols, such as methanol and ethanol, at a temperature and pressure over the critical point of the mixture

Triglyceride Alcohol Glycerol Ester Fig. 1. The overall transesterification reaction (R is a small alkyl group, R1, R2 and R3 are a

The reaction mechanism for supercritical transesterification has been proposed to be

Since the actual feedstocks are not composed solely of triglycerides, especially the low-grade feedstocks, but are also contaminated with water and free fatty acids, some side reactions also take place under supercritical conditions (see Section 1.3). For example, the esterification of free fatty acids with alcohols increases the fatty acid alkyl ester content in the biodiesel product, while the thermal cracking of unsaturated fatty acids decreases the esters content. The earlier research on supercritical transesterification mostly employed methanol as the reacting medium and reacting alcohol at the same time due to the fact that it has the lowest critical point and the highest activity (Warabi et al., 2004). Ethanol is also an interesting candidate because it can be industrially produced from renewable sources in many countries nowadays. However, other supercritical mediums, such as methyl acetate (Saka & Isayama, 2009) and dimethyl carbonate (Ilham & Saka, 2009; Tan et al., 2010b), have also

OH

OH

+

R

R

R

O R1

O

O R2

O

O R3

O

OH

(see Section 1.1). The overall transesterification reaction is shown in Fig. 1.

+

R OH

R OH

R OH

somewhat alike the acidic-catalyzed reaction as described in Section 1.2.

 Introduction**

fatty acid chain)

Somkiat Ngamprasertsith and Ruengwit Sawangkeaw *Fuels Research Center, Department of Chemical Technology,*

*Center for Petroleum, Petrochemicals and Advance Materials,*

*Faculty of Science, Chulalongkorn University,*

*Chulalongkorn University,*

Zhang, Y.; Dube, M. A.; McLean, D. D. & Kates, M. (2003). Biodiesel production from waste cooking oil: 1. Process design and technological assessment. *Bioresource Technology*, Vol. 89(1), pp. 1-16.


**Adaptive Nonlinear Regulation Control of Thermoacoustic Oscillations in Rijke-Type Systems** Provisional chapter Adaptive Nonlinear Regulation Control of

DOI: 10.5772/intechopen.70683

Thermoacoustic Oscillations in Rijke-Type Systems

William MacKunis, Mahmut Reyhanoglu and

Krishna Bhavithavya Kidambi William MacKunis, Mahmut Reyhanoglu and

Additional information is available at the end of the chapter Krishna Bhavithavya Kidambi

http://dx.doi.org/10.5772/intechopen.70683 Additional information is available at the end of the chapter

#### Abstract

[3] Fay G. Derivation of the Aerodynamic Forces for the Mesicopter Simulation. California,

[4] Bouabdallah S. Design and control of quadrotors with application to autonomous flying

[5] Krizhevsky A, Sutskever I, Hinton GE. ImageNet Classification with Deep Convolutional Neural Networks. Advances in Neural Information Processing Systems 25; 2012. pp. 1097– 1105. URL: http://papers.nips.cc/paper/4824-imagenet-classification-with-deep-convolutional-

[6] Szegedy C, Liu W, Jia Y, Sermanet P, Reed S, Anguelov D, Erhan D, Vanhoucke V, Rabinovich A. Going Deeper with Convolutions. Computer Vision and Pattern Recogni-

[7] Bengio Y. Practical Recommendations for Gradient-Based Training of Deep Architectures.

[8] Goodfellow I, Bengio Y, Courville A. Deep Learning. MIT Press; 2016. URL: http://www.

[9] Welford BP. Note on a method for calculating corrected sums of squares and products.

USA: Stanford University; 2001

neural-networks.pdf

160 Adaptive Robust Control Systems

deeplearningbook.org

[Thesis]. EPFL; 2007. DOI: 10.5075/epfl-thesis-3727

tion (CVPR); 2015. URL: http://arxiv.org/abs/1409.4842

CoRR.2012;abs/1206.5533. DOI: arXiv:1206.5533

Technometrics. 1962:419-420. DOI: 10.2307/1266577

Adaptive nonlinear control of self-excited oscillations in Rijke-type thermoacoustic systems is considered. To demonstrate the methodology, a well-accepted thermoacoustic dynamic model is introduced, which includes arrays of sensors and monopole-like actuators. To facilitate the derivation of the adaptive control law, the dynamic model is recast as a set of nonlinear ordinary differential equations, which are amenable to control design. The control-oriented nonlinear model includes unknown, unmeasurable, nonvanishing disturbances in addition to parametric uncertainty in both the thermoacoustic dynamic model and the actuator dynamic model. To compensate for the unmodeled disturbances in the dynamic model, a robust nonlinear feedback term is included in the control law. One of the primary challenges in the control design is the presence of input-multiplicative parametric uncertainty in the dynamic model for the control actuator. This challenge is mitigated through innovative algebraic manipulation in the regulation error system derivation along with a Lyapunov-based adaptive control law. To address practical implementation considerations, where sensor measurements of the complete state are not available for feedback, a detailed analysis is provided to demonstrate that system observability can be ensured through judicious placement of pressure (and/or velocity) sensors. Based on this observability condition, a sliding-mode observer design is presented, which is shown to estimate the unmeasurable states using only the available sensor measurements. A detailed Lyapunov-based stability analysis is provided to prove that the proposed closed-loop active thermoacoustic control system achieves asymptotic (zero steady-state error) regulation of multiple thermoacoustic modes in the presence of the aforementioned model uncertainty. Numerical Monte Carlo-type simulation results are also provided, which demonstrate the performance of the proposed closed-loop control system under various sets of operating conditions.

Keywords: thermoacoustics, robust, adaptive, nonlinear control

© 2018 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.


*2.2. Analysis Stability of Equilibrium Points*

According to the concept of the Hartman–Grobman theorem, the hyperbolic equilibrium point in the neighborhood of a nonlinear dynamical system is topologically equivalent to its linearization. Therefore, the Jacobian of the nonlinear dynamic of (1) is computed as follows:

$$J[N\_\prime I] = \begin{bmatrix} F\_N[N\_\prime I] & F\_I[N\_\prime I] \\ G\_N[N\_\prime I] & G\_I[N\_\prime I] \end{bmatrix} \tag{2}$$

where *F*[*N*, *I*] = *dNdt* and *G*[*N*, *I*] = *dI dt* . The stability cases according to the above equilibrium points are as follows:

1. Stability of primary response stage- *p*1: Under the hypothesis of the IHDM, the immune system is able to protect the human body from developing diseases. This means that it responds directly in cases of emergency such as the appearance of abnormal cells in the tissue. The Jacobian (2) at equilibrium point *p*1 is computed as:

$$J[N,I]\_{p\_1} = \begin{pmatrix} r - \eta \frac{\sigma}{\delta} & -0\\ \frac{m\rho\sigma}{m^2\delta} - \mu \frac{\sigma}{\delta} & -\delta \end{pmatrix} . \tag{3}$$

**Proposition 1.** *Since the immune system is strong, the equilibrium point p*1 *is a stable node.*

**Proof.** From the Jacobian (3), the eigenvalues are given by

$$
\lambda\_1 = -\delta < 0,
$$

$$
\lambda\_2 = r - \eta \frac{\sigma}{\delta} = r - \eta I(0) < 0 \Leftrightarrow I(0) > \frac{r}{\eta},
$$

where 0 < *δ* < 1, then,

$$
\delta^{-1} \ge 1 \Rightarrow \lambda\_2 < \lambda\_1 < 0.
$$

Hence, the equilibrium point *p*1 is a stable node, see Figure 2.

2. Stability of interaction stage- *p*2: This stage describes the ability of the immune cells to inhibit and eliminate the abnormal cells to prevent them from progressing to cancer over many years. We consider the model as having a significant interaction if abnormal cells are dying or being inhibited by the immune cells. This means that parameter *β* → 0 at *t* → ∞. To examine the stability of equilibrium point *p*2 = ( −*r*(*δ*+*mμ*−*ρ*)+*ησ* √Δ 2*rμ* , *r η* ), we compute the Jacobian (2) at this point as

*J*[*N*, *I*]*p*2 = ⎛ ⎝ −*β μ x* −*η* 2*rμ x rμ η* (−1 + 4*mμρr*2 *y*2 ) −*ησ r* ⎞ ⎠ , (4)

where

$$\begin{array}{rcl} x & = & -r(\delta + m\mu - \rho) + \eta\sigma + \sqrt{\Delta}, \\ y & = & -r\delta + rm\mu + r\rho + \eta\sigma + \sqrt{\Delta}. \end{array}$$

**Proposition 2.** *There is an unstable saddle equilibrium point during the interaction stage.*

**Proof.** From the Jacobian (4), the characterized equation is given by

$$(\frac{-\beta}{\mu}\mathbf{x} - \lambda)(\frac{-\eta\sigma}{r} - \lambda) - \frac{r\mu}{\eta}(-1 + \frac{4m\mu\rho r^2}{y^2})(\frac{\eta}{2r\mu}\mathbf{x}) = 0\tag{5}$$

$$(\frac{-\beta}{\mu}x - \lambda)(\frac{-\eta\sigma}{r} - \lambda) - (-1 + \frac{4m\mu\rho r^2}{y^2})(\frac{1}{2}x) = 0. \tag{6}$$

We assume that *C*1 = *x*2 (−1 + 4*mμρr*2 *y*2 ) > 0. Then, we rewrite (6) as follows:

$$
\lambda^2 + (\frac{\beta \mathbf{x}}{\mu} + \frac{\eta \sigma}{r})\lambda + (\frac{-\eta \sigma}{r})(\frac{\beta \mathbf{x}}{\mu}) - \mathbb{C}\_1 = 0. \tag{7}
$$

Since, under the hypotheses of the IHDM, *β* → 0 at *t* → ∞, Equation (7) is computed as

$$
\lambda^2 + \frac{\eta \sigma}{r} \lambda - \mathbb{C}\_1 = 0. \tag{8}
$$

Now, we apply the Routh–Hurwitz theorem for (8), giving

$$
\begin{vmatrix}
\lambda^2 & 1 & -\mathbf{C}\_1 \\
\lambda^1 & \frac{\eta \sigma}{r} & 0 \\
\lambda^0 & -\mathbf{C}\_1 & 0
\end{vmatrix}
$$

Since the first column has one sign change, the equilibrium point *p*2 is an unstable saddle.

3. Stability of recovery stage- *p*3: According to the physiological process, the number of immune cells which are involved in the interaction starts to reduce automatically after inhibiting and eliminating the abnormal cells. Furthermore, the normal cells divide and grow, taking the place of the removed abnormal cells. To examine the stability of this point, we compute the Jacobian at *p*3 = (*β*−1, *β*(1+*mβ*)*σ* (1+*mβ*)(*βδ*+*μ*)−*βρ* ) as follows:

$$J[N,I]\_{\mathbb{P}3} = \begin{pmatrix} \frac{-rz + \beta \eta (1 + m\beta)\tau}{z} & \frac{-\eta}{\beta} \\ \frac{\beta(-(1 + m\beta)^2 \mu + m\beta^2 \rho)\tau}{z(1 + m\beta)} & -\frac{z}{\beta + m\beta^2} \end{pmatrix} \tag{9}$$

where *z* = *β*(*δ* + *mμ* − *ρ*) + *mδβ*2 + *βη*(1 + *mβ*)*σ* > 0.

**Proposition 3.** *In the recovery stage, the system might to be stable.*

**Proof.** The characterized equation of (9) is given by

$$(\frac{-rz+\beta\eta(1+m\beta)\sigma}{z}-\lambda)(-\frac{z}{\beta+m\beta^2}-\lambda)-\mathcal{C}\_2=0,\tag{10}$$

where

$$\mathcal{C}\_2 = \left(\frac{-\eta}{\beta}\right) \left(\frac{\mathbb{B}(-(1+m\beta)^2\mu + m\beta^2\rho)\sigma}{z(1+m\beta)}\right) > 0.1$$

To simplify, we let

$$A = \frac{-rz + \beta \eta (1 + m\beta)\sigma}{z} - \frac{z}{\beta + m\beta^2} < 0$$

and

$$B = \left(\frac{-rz + \beta \eta (1 + m\beta) \sigma}{z}\right) \left(-\frac{z}{\beta + m\beta^2}\right) > 0.1$$

Then, Equation (10) is rewritten as

$$
\lambda^2 - A\lambda + D = 0,\tag{11}
$$

where *D* = *B* − *C*2 > 0. We apply the Routh–Hurwitz theorem for (11) to determine the sign of roots:

$$
\begin{vmatrix}
\lambda^2 & 1 & D \\
\lambda^1 & -A & 0 \\
\lambda^0 & D & 0
\end{vmatrix}
$$

Since *A* < 0, the sign of elements in first column is positive and the equilibrium point *p*3 is called a stable node point for the IHDM.

With reference to propositions (1,2,3), we conclude this section with the following remark:


**9. Conclusions**

In this work, we proposed three different approaches for estimating the quadratic forms of the type *xTA*−*mx*, *m* ∈ N. Specifically, we considered a projection method, a minimization approach, and a heuristic procedure. We also expressed upper bounds on the absolute error of the derived estimates; they allowed us to assess the precision of the results obtained by the aforementioned methods.

The proposed approaches provide efficient and fast estimates. Their efficiency was illustrated by numerical examples. Comparing the proposed estimates with the corresponding ones presented in the literature, we formed the following conclusions.

**Author Contributions:** Conceptualization, M.M., P.R., and O.T.; methodology, M.M., P.R., and O.T.; software, A.P. and P.R.; validation, M.M., P.R., and O.T.; formal analysis, A.P. and P.R.; investigation, M.M., A.P., P.R., and O.T.; data curation, A.P. and P.R.; writing—original draft preparation, M.M., P.R., and O.T.; writing—review and editing, M.M., P.R., and O.T.; visualization, A.P. and P.R.; supervision, M.M.; project administration, M.M. All authors have read and agreed to the published version of the manuscript.

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

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

**Informed Consent Statement:** Not applicable.

**Acknowledgments:** We thank the reviewers of the paper for the valuable remarks. This paper is dedicated to Constantin M. Petridi.

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


*4.1. Clinical Implications*

Inertial measurement technologies enable clinicians to capture patients' movement during unconstrained activities—whether in the clinic or during daily living within their home environment. As these tools become more accessible to therapists and patients, the information they provide has the potential to help improve diagnosis and recommendations for therapeutic interventions or rehabilitation strategies. Additionally, they can facilitate the collection of clinical trial outcome measures in most outpatient clinics, rather than specialized laboratory settings. Nonetheless, we note that IMU-based systems are not a replacement for clinical experience, but rather a tool that can complement clinical judgment. Furthermore, future studies are needed to determine the feasibly of using these systems during rehabilitation programs to monitor compliance and the progression of exercise intensity.


**Author details**

Immacolata Belviso, Veronica Romano, Daria Nurzynska, Clotilde Castaldo\* and Franca Di Meglio Department of Public Health, University of Naples Federico II, Naples, Italy

\*Address all correspondence to<EMAIL_ADDRESS>
© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Meet the editor

Professor Ilze Strumfa, MD, Ph.D., is an outstanding medical lecturer, actively involved in research in pathology. She graduated from the Medical Academy of Latvia with distinction in 1998, underwent board certification in pathology in 2001, and received a Ph.D. degree in 2005. Currently, she is a professor and head of the Department of Pathology, at Riga Stradins University (RSU), Riga, Latvia. Her 14 years of teaching ex-

perience culminated in 2018 in the award of the RSU Lecturer of the Year, given to the most distinguished teachers. As the head of the Department of Pathology, she leads a skilled, motivated team of teachers and scientists whose awards have included Best Academic Unit (2011), Best Ph.D. Student (2012), and Best Digital Junior Teacher (2016). Prof. Strumfa is the author/co-author of more than 100 peer-reviewed journal articles and 16 chapters in scientific monographs/medical textbooks, as well as the editor of three monographs. She has acted as the leading expert in several European and national research projects devoted to the development of diagnostic technologies, laboratory training in research, cancer pathology and tumour microenvironment. Her main research interests include morphological and molecular diagnostics and prognostic assessment of tumours as well as digital pathology and other innovations in pathology and cytology.


**7.3 Military certification**

There is a difference in concept of civil and military aircraft certification. While military certification has a general concern of airworthiness as well as

#### **Table 1.**

*Design consideration—Civil and military aircraft [13].*

rules for design and performance evaluations, each country has its own rule to 'self-certify' its state aircraft as airworthy and compliant to some specified and controlled airspace performance requirements. While certifying a military aircraft, the operational risk and operational process are defined for each type of aircraft. Even though the purpose of airworthiness control is the same, the civil and military certification differs on the fact that [13]:

Military certification also differs from civil procedure due to the fact that military certification looks for induction of the aircraft into service use. The certification tasks also include vehicle performance evaluation and system qualification for induction into service. The induction clearance is given through issue of 'release to service' document. The general certification procedure follows the following routes:

**19**

*Military Aviation Principles*

programme.

flight tests.

fied elements like:

[13, 14, 18–27, 29].

a.Handling qualities

c.Specific operations in wartime

d.Military role and mission and tasks

*DOI: http://dx.doi.org/10.5772/intechopen.87087*

f. Finally a 'release to service document' is issued.

b.Weapons, ammunition stores and self-defence suites

*7.4.1 Military certification procedure in the United Kingdom*

General of the MAA (DGMAA) is accountable to SofS, for:

b.According airworthy clearance through certification

now been superseded by RA 5800 and RA 5820 [19–21].

c.Approving aircraft inspection process for the acquisition

a.Providing airworthiness regulatory framework

defence aviation environment

**7.4 Military certifications in different countries**

d.Finally the aircraft-level performance is evaluated through flight test

e.A compliance document is prepared capturing the evidences generated through analysis, lab test, aircraft inspection, system integration test and

Military aviation is an important factor in security and defence preparedness of each state. All military airworthiness activities are conducted and regulated on a national basis, and in general most military authorities have not published military airworthiness design standards for an acceptable level of safety. In general for the military airplanes, the military specification and documents nominate some speci-

While the principle remains the same, the practices evolved in different countries over a period of time, differ from each other to a varying degree. The range of control over all the activities in design, development evaluation, and testing varies from total control to delegated system of working, with emphasis on contracts and penalties for shortfalls in performance, time and cost overruns

With effect from 1 April 2010, the Secretary of State (SofS) for Defence created the Military Aviation Authority (MAA) by charter as the single independent regulatory body for all defence aviation activities in the United Kingdom. The Director

d.According airworthiness assurance of all air systems held in the inventory of

Accordingly DGMAA prepares and releases regulatory publications (MRP) and has the authority to issue them on behalf of the SofS. The MAA has published the document 'RA 1500 – Certification of UK Military Air Systems'. This document has *Military Engineering*

Accepted failure tolerance/flight

Use of advanced technology

Stealth tech/EW protection

**Table 1.**

rules for design and performance evaluations, each country has its own rule to 'self-certify' its state aircraft as airworthy and compliant to some specified and controlled airspace performance requirements. While certifying a military aircraft, the operational risk and operational process are defined for each type of aircraft. Even though the purpose of airworthiness control is the same, the civil and military

Design life High economic life High maneuverability, extreme

**Objectives Civil aircraft design Military aircraft design** Requirement Independent market survey Military staff requirement

flying hours

Providing national security Issue operational clearance

As per Mil-STD-882; permitted failure

flying hours

High performance, navigation and weapon aiming, secure COM and reduction in pilot workload

Level 2: p < 10−2 Level 3: p < 10−4

rate 1 in 107

under development

operating envelope

Only certified material/technology Cutting edge technology; certified/

Not considered Most essential consideration

Certification goal Civil-type certification used by airlines

Design safety As per SAE ARP 4671; permitted

Avionics architecture Better FCS, navigation, reduce pilot

Level 2: p < 10−4 Level 3: p < 10−6

failure rate 1 in 109

workload, increase payload

c.Military certifications differ on the degree and coverage of the evidences

needed. This is in general limited by contract, budget, lack of past legal liability

d.Acceptance of specific tasks and the risk levels can vary with aircraft purpose

Military certification also differs from civil procedure due to the fact that military certification looks for induction of the aircraft into service use. The certification tasks also include vehicle performance evaluation and system qualification for induction into service. The induction clearance is given through issue of 'release to service' document. The general certification procedure follows the following routes:

b.The first-level clearance includes qualification of component and equipment

c.The second-level clearance includes demonstration of systems' performance

certification differs on the fact that [13]:

*Design consideration—Civil and military aircraft [13].*

and aircraft type and legacy.

through lab-level test.

and type.

a.Governments can 'self-certify' their state aircraft.

a.Approval builds up in a building block method.

through aircraft on ground tests and system simulations.

b.Operational risk is defined and accepted by the service.

**18**


**4. Analysis and Results**

Regarding the two variables—housing value and housing added value—two of the same sets of independent variables were put into two respective models: an OLS model based on mean estimation and a QR model based on 19 quantiles.

The parameter estimation of quantile regression parameters adopts the bootstrap method. Every quantile model conducts 500 samplings with replacements of initial samples. Clustered standard error is used with different cities as different clusters to estimate standard deviation.

Compared with the general robust standard error, a clustered standard error presumes that the random error terms in the regression equations are uncorrelated among cities but correlated within cities, and this helps to accurately estimate the vast difference among Chinese regions and strengthen the model; however, it has one disadvantage. The *p*-value of a clustered standard error is higher than that of a robust standard error and is less significant.


60. **The incremental approach to the security budget will likely provide inadequate resources for some security agencies; thus, it is likely that some agencies could end up with a financing gap even after careful prioritization.** Such an approach is based on historical budget trends23 rather than the sector strategic priorities over the medium-term. Given the major role that security services play in social and economic development, the resource allocation should be based on the priorities of the security sector and expected results rather than an incremental budget. The strategic approach to budget allocation could either increase or maintain the level of resource allocation for a security agency depending on the relative priority and the expected results.

61. **Increased investment in the Liberia Coast Guard (LCG) and the Bureau for Customs and Excise (BCE) has the potential to increase revenue.** The consultant report suggested that further investment in the LCG and the BCE could have a dual advantage of both increasing security and revenue enhancement given that investment to scale up capacity of the LCG and BCE is estimated to be small. The revenue could be earmarked to the security sector in agreement with the MOF. By contrast, non-tax revenues including fees (visa and resident applications) and fines (illegal fishing, court and police) collected by the LNP, BIN, Customs, and Judiciary will likely be low.24 It will not increase significantly over the next three years given the level of poverty, lack of trust in security agents, and widespread informal payments25 in the security sector. While this doesn't close the gap significantly, the fees could cover some annual running costs in the sector when combined with other agencies' revenue generation.

62. **The government should seek to mobilize additional external grants to help close the gap.** Given Liberia's fragility and development needs, external partners should be more willing to assist if security activities are efficiently managed and well prioritized. An initiative that could appeal to donors is support for increasing training capacity at the National Police Training Academy (logistics, infrastructure, instructors, etc). Additionally, the government may appeal to donors to target their assistance towards critical security services such as those provided by LNP and BIN. Co-financing through the Justice and Security Trust Fund based on the work plan for the Justice and Security Joint Program could be instrumental to attract resources from both bilateral and multi-lateral donors.

63. Table 7 provides a summary of a road map towards sustainability of the security services during the UNMIL transition.

23 It is calculated as an average of public spending on the security sector as a ratio to GDP during the past three years (2009-2011), equivalent to 4.9 percent of GDP.

24 NPL remitted around US\$100,000 of fees and fines in 2008; BIN remitted around US\$450,000 in 2008, of which 98% was for residence permits; and courts remitted just over US\$10,000 for the fees and fines issued.

25 These payments are related to the delivery of certain security services within the police force (e.g., to enable arrests of suspects requiring lengthy journeys), prisons (e.g., to enable a pre-trial or convicted person to be moved from court to prison), immigration (e.g., rapid goods inspection charges) and the courts (e.g., to fast track proceedings).

## **VII. The Way Forward**

64. **The MTEF for next year's budget will be an entry point for the security sector to ensure that strategic priorities are consistent with the availability of resources.** The MTEF process involves establishing a resource ceiling and the medium-term costing of both ongoing services and the functions to be assumed after the UNMIL drawdown. The process will set in motion an assessment of the resource allocation for the security sector and trade-offs among various activities at the agency and sector levels. A realistic resource envelope for the security sector should be based on prioritized needs aligned with the sector's policy, not on an historical resource allocation rule. Meanwhile, fine-turning of the medium-term costing will require the government to revise the costing and make trade-offs among various programs without compromising security outcomes while balancing current and capital expenditures. Trade-off decisions are reached through the alignment of security priorities at the agency and sector levels. The final outcome will be a re-prioritization of activities that take into account resource constraints and the eventual intra-sectoral reallocation of budgetary resources within an agency and throughout the security sector.

65. **The NSC needs to play a proactive role in the MTEF process.** As a body responsible for coordinating security sector policy, the NSC should participate in taking decisions concerning the security resource envelope and sector priorities. Currently, the resource envelope for the sector is set by the Ministry of Finance with minimum input from the security sector. The minister will need to be an ever present member of the NSC, the body entrusted to provide security policy advice to the government. Further, the NSC will need to participate in discussions on the MTEF process that sets the resource envelope and establishes priorities for the sector. Close involvement of the security sector in this process is critical if effectiveness and efficiency are to be ensured.

66. **Individual security agencies need to revise their own strategic plans.** The revised plans should identify security priorities consistent with the security strategic objectives articulated in the AfT and take into account the security transition plan to be finalized. These plans should be realistically costed based on the available resources informed by the medium-term expenditure framework next year.

67. **Efforts should be focused on making the delivery of security services, both ongoing and new, to be as cost effective as possible.** These include a realistic target for security personnel and the rational investment cost for infrastructure, logistics and equipment. Improving the efficiency of security service provisioning could involve deepening reforms on various fronts including institutional and human resource management as well as public financial management.

68. **A strategic prioritization of the security functions should go hand in hand with a strategic budget allocation for the security sector.** This approach will promote strategic budget planning that focuses on achieving results rather than on incremental budgeting for the security sector.

69. Finally, a decision must be made with regard to the phasing of construction and operation of regional hubs over time given the limited available resources and the recurrent cost to operate and maintain the hubs.

## **REFERENCES**

Carnahan, M et al, 2006, "Economic Impact of Peacekeeping", Peace Dividend Trust/UN Peacekeeping, New York, USA

Carnaham, M., Durch, W., and Gilmore S. (2006), "Economic Impact of Peacekeeping," UN Department of Peacekeeping Operation.

Geopolicity (2012), Security Sector Expenditure Review Liberia

International Monetary Fund (July 2011), Seventh Review under the Three-Year Arrangement under the Extended Credit Facility.

OECD DAC Handbook on Security Sector Reform, supporting security and justice, (2007).

Republic of Liberia (2003), Accra Comprehensive Peace Accords

Republic of Liberia (2008), National Security Strategy

Republic of Liberia (2003),

Republic of Liberia (2008), New National Defense Act

Republic of Liberia (2003), National Security Reform and Intelligence Act.

Republic of Liberia (2012), Lift Liberia Poverty Reduction Strategy - A Result Focused Assessment (June 2008-December 2011)

United Nations, *UN annual budget and financial reports to the General Assembly*

United Nations Security Council, www.**un**.org/Docs/sc/

United Nations Security Council (2012), Special Report of the Security General on the United Nations Mission in Liberia, S/2012/230.

World Bank and UNMIL

## **Money Matters: Addressing the Financial Sustainability of Security Sector Reform**

Rory Keane and Thorodd Ommundsen

Although the financial sustainability of United Nations (UN) support to institutional capacity building in post-conflict contexts may be the least analysed topic on the peacebuilding agenda, understanding the costs of rebuilding and maintaining the security sector should be one of the most important priorities for security sector reform (SSR) practitioners today. Through innovative partnerships between the UN and the World Bank, a new and important practice area in public financial management of the security sector is beginning to take shape. This paper traces the new demands placed on peacekeeping operations to "get more bang for every peacekeeping buck", and explores how to match SSR priorities and recurring costs in the security sector with available resources over the long term. In presenting the lessons learned from the security sector public expenditure review conducted by the UN and the World Bank in Liberia in 2012, the first such review jointly undertaken by the two organizations, the paper seeks to illustrate how the discussion on right-sizing of the security sector can go hand in hand with a discussion on right-financing in order to help prioritize key reforms pragmatically in light of the available fiscal space. Specifically, the paper provides SSR practitioners with insights into the challenges often encountered when assisting national authorities to address the political economy of SSR, and how to navigate those dilemmas.

**Rory Keane** currently heads the UN Liaison Office for Peace and Security in Brussels. Previously he served as the SSR adviser to the Special Representative of the Secretary-General in Liberia between 2010 and 2012, where he led the first security sector public expenditure review undertaken jointly by the UN and the World Bank. He has published broadly on issues related to SSR, human security, peacebuilding, the EU Common Security and Defence Policy and conflict dynamics in fragile settings.

**Thorodd Ommundsen** serves as an SSR officer with the SSR Unit in the Office of Rule of Law and Security Institutions, UN Department of Peacekeeping Operations. In his capacity as the unit's focal point for the World Bank partnership, he contributed to the security sector public expenditure reviews in Liberia (2012) and Somalia (2015). Previously he worked for the Ministry of Internal Affairs in Liberia and the Permanent Mission of Norway to the UN, and has served with a number of international non-governmental organizations.

**SSR Paper 11** **SSR Paper 11**

**Money Matters: Addressing the Financial Sustainability of Security Sector Reform**

**Money Matters: Addressing**

**the Financial Sustainability**

**of Security Sector Reform**

Rory Keane and Thorodd Ommundsen


Preface

The book is composed of seven chapters that describe the synthesis, characterization and application of cobalt in recent technologies. Various topics are discussed in the book, such as: the general aspects of cobalt chemistry, synthesis of cobalt and cobalt oxide by different chemical techniques, substitution and redox properties of some organo-isocyanide cobalt complexes and effect of cobalt on morphology of microhole formed by micropunching and a review of radionuclide cobalt-60 as a fine-sediment tracer. Each chapter is written clearly and precisely and illustrates easier understanding of the phenomena described in it. This book addresses not only scientists in specialized fields, but also doctorate students, postdoc‐ toral researchers and technical professionals.

All authors that contributed to this book are very active and competent in their field, and therefore this book provides up-to-date information about the concerned topics. The content of the book provides fundamental preparation needed for further study of advanced topics on cobalt and its application. At the end of each chapter, proper references are included that can lead the readers to the best sources in the literature and help them to go into more de‐ tails about the concerned topic.

I am grateful to all the authors who are experts in their fields for helping me to complete this project and also to the entire InTech publishing team for making this project possible. I am very thankful to the Publishing Process Manager Ms. Iva Simcic for her cooperative attitude during the entire reviewing and publishing processes. I hope that this book will provide an opportunity to the readers to strengthen their knowledge and capabilities in the relevant field.

> **Dr. Khan Maaz** Pakistan Institute of Nuclear Science and Technology Pakistan

**Provisional chapter**


*2.8. Statistical Analysis*

The statistical analysis was carried out using the Statistica software program (StatSoft, Inc., Tulsa, OK, USA). All the rheological analyses were conducted in triplicate. The standard deviation and mean values were presented. ANOVA was conducted to determine the differences in rheological parameters of gum solutions. Duncan, multiple comparison tests at 95% significance level were used to determine the effect of analysis parameters.


**1. Introduction**

Cities are numbers of communities and neighborhoods where people can work live and have entertainment. Day by day cities offer tremendous opportunities for community, employment, education, excitement and interest. For all of these reasons, cities became attractive areas for living and more than half of the world's population are living in cities [1]. On the other hand, cities create problems of congestion, noise, and pollution, but most people do not have the choice, recognizing the trade-offs. How to live and getting the right balance are parts of the solution. Living in towns and low-density cities has some advantages, however people may like living in a compact and dense city as far as there is an equilibrium among the development elements; built area and open spaces, private and public transportation, using natural and artificial resources [2]. City, community or neighborhoods could be considered as a system of depending components [3]. The major variables or components that affect the design of any development are; urban form, transport, landscape, building design, waste management, energy and water supply. The most sustainable design is about equilibrium among these components [4]. In order to make cities or neighborhoods more suitable for people, all aspects of viable city and neighborhoods are required to involve and operate smoothly within design or system equation.

 Shareef, S.; Altan, Sustainability at an Urban Level: A Case Study of a Neighborhood in Dubai, UAE. *Sustainability* **2021**, *13*,4355. https://doi.org/10.3390/ su13084355

H.

**Citation:**

Academic Editor: Abdollah Shafieezadeh

Received: 24 February 2021 Accepted: 8 April 2021 Published: 14 April 2021

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

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

It is obvious that communities and city growth becomes a key issue in the global problems of climate change, global warming, greenhouse gas emissions, and depleting natural resources. Therefore, many studies and publications have explored the relationship between the sustainability levels required to be achieved and the urban planning of any development. Many of these studies concentrated on the main urban design factors, such as urban form, building design, liveability, land use, and transportation system to analyse, evaluate and develop the sustainability level of cities and developments [5,6]. However, some of these researchers studied sustainability on an urban scale from the aspect of resource conservation and pollution reduction. Cities and urban environment pollution are caused by different factors; density and transport within cities, human activities, construction and buildings' effects on nature and landscape areas, atmospheric pollution by CO2 emissions, and noise pollution [7]. Pollution influences human health and wellbeing and can make cities uneasy places to live. Greenhouse gas (GHG) averages constitute one of the most used air pollution indicators. Greenhouse gas emissions refer to all gases that trap heat in the atmosphere; the main greenhouse gases in the atmosphere are; carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). These gases are the main reason for global warming, depleting the ozone layer, and climate change [8]. GHG are emitted through various fossil fuel burning processes. Fossil fuels (coal, natural gas, and oil) are burnt for heating, solid waste burning, trees, and wood products; the decay of organic waste in municipal solid waste landfills, chemical reactions, and manufacturing operations are some resources of GHG [9].

Furthermore, the building and construction industry, transportation, agriculture, and industry are the major recourses of these gases. Global warming, urban heat island (UHI), and the increase in global air temperature are a result of GHG emission. Buildings design, transportation systems, and open areas significantly affect the sustainability of the urban level. Buildings contribute to the CO2 emissions by 43%, while the transportation share is 32% [10]. Therefore, cities should be designed in a way that minimizes the GHG averages and pollution percentages. The new cities should be designed to keep their inhabitants healthy, secure, and happy. For this aim, a neighborhood must become greener and robust, with a stable ecosystem. Our built environment at the present time suffers enough and an integrated approach is urgently needed. Successful solutions depend on understanding the relationship among the involved sustainability elements; environmental, historical, social, and economic. The solutions should start from the individual building to the block, neighborhood, district, city, region, and up towards the globe. Furthermore, adopting active urban design strategies, such as using renewable energy (PV) solar panels at the urban level, will enhance the sustainability on an urban and city scale [11].

The terms "Neighborhood" or "Community" refer to a number of residential units and the related facilities that serve the resident's needs [12]. Livable, sustainable neighborhoods are one of the determining and essential factors for developing sustainable environments [13]. The sustainable neighborhood is a neighborhood that integrates the three sustainability pillars "Environment, Economy and Society". From the social aspect, providing the required open areas, landscaped areas, playgrounds, and community facilities will encourage sociality and people communications [14]. From the economic aspect, those sustainable neighborhoods that provide all the services and facilities will create livable, healthy independent communities that will have a positive effect on the individuals and the whole society [15]. However, "The Sustainable Urban Design" provides a high level of sustainability and efficiency in terms of major urban design dimensions, such as livability, land use, transportation, buildings design, landscaped areas, and environmental performance [16,17]. However, "The Sustainable Urban Design" provides a high level of sustainability and efficiency in terms of major urban design dimensions, such as liveability, land use, transportations, buildings design, landscaped areas, and environmental performance.

Urban sustainability is significant to the future of humans; it directly affects people's lifestyle, time, effort, health, wellbeing and welfare [18]. Transportation, resources conservation, indoor, and outdoor thermal comfort represent some of the sustainable urban

design factors that have a direct effect on the livable community. The major challenge for the urban designer is to improve and optimize the relation among the three factors in urban geometry; density, movement and recourses. Sustainability at the urban level could be achieved through optimizing the three aspects of, and finding the best design for, the neighborhood, district and city [19]. The urban areas and communities include buildings, open and green spaces, water features and road networks. These are the urban design elements that should be organized in a way that provides vitality and improves the people's lifestyle [20].

Creating a liveable environment is one of the sustainable urban design principles, and the level of urban liveability could be considered important in achieving sustainability in the urban environment. Urban sustainability can be obtained by creating a liveable community, neighbourhood, and city [20]. Urban liveability covers a number of factors; it is a multi-dimensional construct that includes accessibility, number of public parks and open spaces, walkability, transportation planning, urban density, and land use diversity, all of which are design elements that could be improved to achieve high levels of liveability and sustainability [21]. However, it is difficult to define and measure the concept of urban liveability, and set some principles for liveability measurements, such as safety, equity, and continuity [12]. Moreover, when it comes to accessibility and inclusiveness of the previously mentioned indicators [22], accessibility, land use diversity, providing parks and green areas are of the strategies used when planning a sustainable neighborhood. Passive design also has an effective role in achieving a green and sustainable community by offering recourses efficiency [23,24]. The crucial roles of the green space on ecosystem have already been proven by some researchers [25]. The leakage in accessibility to these areas and other community services affects the community sustainability level; ensuring a good accessibility will improve the community sustainability, and this consequently improves the community social life [25]. The service within the green areas, including sport services, has an impressive impact on peoples' wellbeing, and is resulting with good social relations among the residences [25]. It has been proven that the design and the architecture of the buildings should collaborate with surrounding nature to create a harmony between the outdoor and indoor spaces. The concept of human community should be designed to positively influence the human behavior, health and culture [26]. Other than that, land use diversity is another factor that forms a sustainable community. Land use diversity and ensuring a good accessibility to the daily required services would improve peoples' lifestyle from one side, and have a positive effect on resource saving from the other side [27]. The reduction in the use of transportation and vehicle's journey will consequently have a positive impact environmentally, by reducing CO2 emissions [28,29].

Passive design is one of the strategies that the urban planner can adopt for designing a sustainable community according to its direct effect on outdoor and indoor thermal performance [30]. The urban air temperature is rising in all cities around the world, as a result of global warming and the decrease in the natural and greenery area in cities. This rise in outdoor air temperature consequently affects the thermal performance of the inner space environment and increases the indoor air temperature averages [30]. The impact of buildings and urban geometry on the urban heat island phenomena and the outdoor thermal performance has been proven in many studies [31]. Increasing and enhancing the sustainability of our developments is an urgent matter when it comes to facing global warning, resources limitation, and pollution. Implementing the passive and active design elements on buildings and at the urban level represents a part of the solution [32].

Building design, orientation, and block density are of significant effects in development sustainability [33,34]. Creating a desired shading on urban level will have a positive thermal impact on both outdoor and indoor environments. In the hot climate conditions of the UAE, the reduction in air temperature and solar gain due to the orientation can reach 1.8 ◦C and 13% respectively. [34]. One of the rule of thumb in urban design is the belief that energy consumption decreases when the community or city density increases. This is a challenge to the urban designer to find the best balance between the two variables in

urban planning; density and energy [35]. Furthermore, optimizing the indoor and thermal performance on an urban level will have a positive impact on livability, productivity, and indoor energy consumption [36].

The strong urban structure provides less use or need for transportation and reduces the path, the cycling transportation in the most preferred plan, and different types of transportation plays a significant role in changing the traditional urban structure. The vehicle flow, parking areas, street width, public transportation stations, and many others related to the transit system are the elements that should be well designed to obtain a strong structure [37,38]. Consequently, road planning affects the other urban factors such as gardens and open areas, and playgrounds, which should be counted on during early design stages. The sustainable land use planning is the significant factor in reducing the daily transporting cycle, and increasing walkability as one of the sustainable neighborhood requirements [39]. Furthermore, greenery and landscaped areas could be effective influences on increasing walkability from one side, reducing air temperatures and enhancing outdoor and indoor thermal performances from the other side [40].

The impact of communities and developments has been illustrated previously. The former studies proved the significant impact of sustainable urban design and sustainable developments on reducing the negative environmental effect caused by continuous urbanization. This study aims to contribute to this concept by investigating the potential of improving the performance of one of the Dubai community's performances towards sustainable performance. Hence, a community located in the city of Dubai in the United Arab Emirates (UAE) will be explored, evaluated, and optimized to achieve a sustainable community that follows the sustainable design standards. Dubai is located in the north of the UAE, and extended along the Arabian Gulf with a climate that is known with its humidity during summers, due to its location of the city on Dubai Creek. Generally, the weather in Dubai is sunny most days of the year; in winter, the average temperature is 25 ◦C, while in summer, the temperature may reach up to 38 ◦C, with a high percentage of humidity between 20–60%, and a low average of rainy days. The annual air temperature varied between 17 ◦C in winter and 35 ◦C by a Dubai weather file generated through the Integrated Environmental Solutions—Virtual Environment (IES-VE) software [41].