Maximum power point tracking (MPPT) strategy is one of the major parameters affecting efficiency in photovoltaic (PV) systems. In this paper, distributed MPPT approaches are compared with central mode MPPT. Advantages and disadvantages of submodule level MPPT technique and module level MPPT approach are shown with simulation studies. Comparisons are made with incremental conductance (IC) algorithm. In this context, non-isolated zeta converter is used as a power processing unit. Effect of the MPPT strategy on the collected energy performance is observed by simulation studies performed in MATLAB/Simulink. It is clear by these studies that energy capture is bigger in submodule level MPPT strategy and module level MPPT with respect to central mode which is seen by simulations. However, central mode MPPT offers cost effective solution because of the low hardware requirements.

Detection and diagnosis of breast cancer from diffusion signals by diffusion-weighted imaging involves in estimation of quantitative metrics by signal attenuation models fitted to the signals. The process suffers from the implementation difficulty of the fitting algorithms and their sensitivity to noise. This study aims development of neural networks to facilitate the classification of the breast tissues from the signals. 37500 diffusion MR signals are synthetically generated for noise-free and noisy conditions by signal-to-noise ratio (SNR) for malignant, benign, and healthy breast tissues. Forty neural networks employing traditional long short-term memory (LSTM) or bidirectional long short-term memory (BiLSTM) blocks up to twenty are trained and tested for the signals using bootstrapping incorporated accuracy analysis. Specificity, sensitivity, and accuracy metrics are computed for the higher performance networks. For noise-free and noisy signals with SNR ≥ 80, networks may achieve excellent sensitivities, specificities, and accuracies (100% at all), but LSTM networks require fewer number of memory blocks. For noisy signals having SNRs ≤ 40, the networks may deliver high to very high sensitivities (74.8-98.3%), specificities (87.4-99.2%), and accuracies (83.2-98.9%) better for malignant and healthy tissues than benign tissue but BiLSTM ones perform slightly better. LTSM networks eliminate the need for any signal decay model while outputting remarkably good performances in the classification of diffusion signals. BiLSTM networks perform slightly better for very noisy conditions. Prospective studies are needed to justify the potential benefits in a clinical setup.

Developing technology and growing population are increasing the need of countries for energy every passing day. Renewable energy resources, which are an environmentally friendly and local solution alternative to fossil fuels, are seen to be a significant source of supply in this matter. Among renewable energy resources, hydroelectric energy is in an advantageous position with its reliable potential and sustainable production. With the purpose of utilizing small flowing waters such as rivers and streams and solving problems of access to interconnected grids in rural areas, micro-type hydroelectric power plants have a significant potential for countries. This study carried out the design and performance analyses of permanent magnet synchronous generators with different numbers of poles for micro hydroelectric power plants. The generators’ flux density values and total voltage harmonic distortions were examined. Additionally, the cogging torque magnitudes have been analyzed. The generators were loaded with nominal loads, and the time-dependent waveforms of phase voltages were obtained. By subjecting the obtained voltages to Fourier analysis, their harmonic spectrum was created. Finally, by considering the amount of active material used for the designs, their costs were compared.

Among all the control methods developed for Induction Motor (IM) drivers, the hysteresis controller based Direct Torque Control (DTC) method has an important place. This control method does not require other rotor and stator parameters except the stator resistance and does not require position or velocity sensors. However, there are some disadvantages of the DTC method, such as high torque, flux and current ripples. In this study, in order to reduce the high torque ripples occurring in an induction motor that is controlled by the hysteresis controller based conventional DTC method, a simple and effective Sugeno type Neuro-Fuzzy Torque Controller (NFTC) is proposed. This proposed controller is used instead of hysteresis controller. An experimental setup consisting of 1.1 kW induction motor, current and voltage measurement, DS1103 control card and two-level voltage source inverter was installed. To evaluate the performance of the proposed controller structure, various experimental studies were performed. Results obtained from the proposed NFTC based structure and conventional hysteresis controller based DTC structures are given comparatively. By the obtained experimental results, it was confirmed that the proposed NFTC-based controller structure considerably reduced flux and torque ripples in the motor.

Modeling of unmanned aerial vehicle (UAV) with system identification is very important in terms of its model-based effective control. The modeling of UAV is required for aircraft crashes, analyzing autonomous aircrafts, preventing external disturbances, pre-flight analysis. However, since UAV has nonlinear inherent dynamics including inherent chaoticity and fractality, it becomes difficult to obtain a mathematical model under external disturbance. In this study, some of the inherent nonlinear dynamics of UAV are linearized and the model of UAV is obtained by system identification approaches under external disturbance. The linearized lateral dynamics of a fixed wing UAV is used in this study. Further, the flight motion equations applied to fixed wing UAV have been utilized for obtaining the coefficients of lateral model for straight and level flight. The roll angles are calculated using transfer functions for aileron, rudder and deflections inputs. The autoregressive exogenous (ARX), autoregressive moving average with exogenous (ARMAX) and output error (OE) parametric system identification approaches are performed to estimate UAV lateral dynamic system response as using empirical input-output data sets. The accuracy of parametric model estimation and model degrees are compared for different external disturbance effects.

The economic power dispatch (EPD) is an integral part of the power system, and the major roles and purpose of its use are for achieving a reliable and efficient operation out of power system generation networks, and this operation should be obtained by minimizing the generator fuel cost. Getting optimal solutions to EPD problem requires efficient optimization algorithms. Novel Bat Algorithm (NBA) is one of the most recent methods and it has already proven its efficiency and reliability for solving the EPD problem. This paper proposes Novel Bat Algorithm (NBA) in order to solve the EPD problem based on the large scale power system. The NBA has proved its efficiency and it gave a perfect performance for small-scale systems compared with the original Bat algorithm (BA), because of considering the Doppler Effect and assumed that bat can move between various habitats. The study of the EPD for large-scale power systems is more important than study it for small ones, because all power systems in countries are considered large networks. This is why all modern studies focus on the study of EPD for large systems. To test the performance of NBA during small and large scale power system, we have applied it to many systems, including 3-thermal units, 6-thermal units, 31-Iraqi thermal units and IEEE 40-thermal units respectively, with transmission losses and generator limits, and we have made a comparison of the obtained results of NBA with other optimization methods. The Iraqi thermal units have been utilized as a new data.

In this study, a six-leg spider robot (hexapod) was designed and controlled for greenhouse, search and rescue operations and military applications. Solidworks design program was used in the design stage and Matlab Simulink program was used in the control stage of the robot. In the study, a motion trajectory was determined by interpolation technique for the robot and it was aimed to move on this trajectory. Proportional-Integral-Differential (PID) controller and Fuzzy Logic Controller (FLC) were used for the trajectory control of the robot. The robot walk movements were applied in both control types with motion on flat ground, motion on inclined ground, motion at different weights and different friction coefficients. In the analysis studies, the total weight of the robot was taken into consideration as 4kg. As a result of the analysis studies, it was observed that this robot, which was designed and analyzed, followed a trajectory defined by a mass of 4 kg with an error value of 1 mm on average. During the trajectory tracking, it was found that the Fuzzy controller performs better than the PID controller at the turning points of the reference trajectory curve of the robot.

To ensure energy continuity in the interconnected power systems, production and consumption amounts should be in balance, and that can be possible by providing constant voltage and frequency. Otherwise, undesirable large dynamic oscillations, voltage collapse may occur, and the quality of the electrical energy deteriorates. In this study, the power system of the Denizli Region in the Western Mediterranean Region is modeled using realistic national data. The simulation study is carried out to obtain the voltages, active and reactive powers of buses in the case of no-fault and fault occurrence. Using FACTS (Flexible Alternating Current Transmission Systems) technology such as SVC and STATCOM, the power systems can be controlled, and the carrying capacities can be improved within specified limits. Facts devices are capable of producing and consuming reactive power depending on immediate needs, safe and operating flexibility, and having a high reaction time in the simulation studies. The maximum load limits are increased, and the control of the power system is facilitated. STATCOM provides 31.09 % more achievement with respect to SVC device at energy production and consumption rates for the modeled pilot region. The reliability of the power system has been increased against a voltage collapse, thanks to the SVC and STATCOM controllers. Furthermore, the voltage stability of the generator is also raised, and correspondingly the capacity of the power system enhances. The results are compared to the existing system, and the obtained improvements may be assessed for the enhancement of the interconnected network grid of Turkey.

In this study, Hybrid Renewable Power System (HRPS) has been designed to meet the energy requirement of Istanbul Gedik University Vocational School (IGUVS) in an optimum way. The energy requirement will be achieved mainly with wind and solar power generation system. The hybrid regenerative power system will be requested from the network when it can’t meet its energy needs. The optimum configuration of grid-connected solar/wind hybrid power generation system will be determined by considering the wind speed data and solar radiation data of the location of IGUVS. Moreover, sensitivity analysis will be carried out taking into consideration the wind speed and solar radiation values. If the optimum hybrid power generation system specified is used, the carbon emission values obtained will be examined.

Among critical stakeholders of software projects developed in public institutions are software developers and project managers affiliated to sub-contractor companies, who are working onsite at the public institutions. The aim of this study is to determine the effect of working onsite in public software projects for software developers and managers with respect to selected factors. The research is designed as an exploratory and qualitative study. The study participants were 10 software developers, one technical team leader and four project managers, all having long experiences in working on public software projects on client premises. Semi-structured interview technique is employed as the data collection method and “ analysis” was applied on the obtained participant responses. Following this analysis, “key ” approach was used to identify the issues to be further considered. It has been determined that the productivity of software developers working onsite at public institutions is low due to intense requests, shortened time to fulfill these requests, and long duration of authorization processes. Moreover, a finding of the study is that the quality of the developed projects and the motivation of the developers are considered to be low for the same aforementioned reasons. Among the foremost causes for these results are the fact that employees work under two different hierarchical structures one in the public institution and one in the software company, more than one managers assign work and there is an authority confusion between organizational units and people in the public institutions.