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Articles 2221 - 2250 of 8897

Full-Text Articles in Physical Sciences and Mathematics

Elimination Of Useless Images From Raw Camera-Trap Data, Ulaş Tekeli̇, Yalin Baştanlar Jan 2019

Elimination Of Useless Images From Raw Camera-Trap Data, Ulaş Tekeli̇, Yalin Baştanlar

Turkish Journal of Electrical Engineering and Computer Sciences

Camera-traps are motion triggered cameras that are used to observe animals in nature. The number of images collected from camera-traps has increased significantly with the widening use of camera-traps thanks to advances in digital technology. A great workload is required for wild-life researchers to group and label these images. We propose a system to decrease the amount of time spent by the researchers by eliminating useless images from raw camera-trap data. These images are too bright, too dark, blurred, or they contain no animals. To eliminate bright, dark, and blurred images we employ techniques based on image histograms and fast …


A Computational Study On Aging Effect For Facial Expression Recognition, Elena Sönmez Jan 2019

A Computational Study On Aging Effect For Facial Expression Recognition, Elena Sönmez

Turkish Journal of Electrical Engineering and Computer Sciences

This work uses newly introduced variations of the sparse representation-based classifier (SRC) to challenge the issue of automatic facial expression recognition (FER) with faces belonging to a wide span of ages. Since facial expression is one of the most powerful and immediate ways to disclose individuals? emotions and intentions, the study of emotional traits is an active research topic both in psychology and in engineering fields. To date, automatic FER systems work well with frontal and clean faces, but disturbance factors can dramatically decrease their performance. Aging is a critical disruption element, which is present in any real-world situation and …


An Analytical Model To Assess Dc Characteristics Of Independent Gate Si Finfets, Umer Farooq Ahmed, Muhammad Mansoor Ahmed Jan 2019

An Analytical Model To Assess Dc Characteristics Of Independent Gate Si Finfets, Umer Farooq Ahmed, Muhammad Mansoor Ahmed

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, Poisson's equation is utilized to find the potential distribution inside the channel of an independent gate FinFET device by adding the effect of channel height. The channel height of the device plays an important role in surface potential calculation when top gate voltage is applied. Using surface potential, an I - V model is developed, which can find the device current both in linear and saturation regions of operation. The model is tested on devices of different dimensions and good agreement between modeled and simulated results is observed, which validates the authenticity of the proposed model.


Low Leakage Pocket Junction-Less Dgtfet With Biosensing Cavity Region, Suman Lata Tripathi, Raju Patel, Vimal Kumar Agrawal Jan 2019

Low Leakage Pocket Junction-Less Dgtfet With Biosensing Cavity Region, Suman Lata Tripathi, Raju Patel, Vimal Kumar Agrawal

Turkish Journal of Electrical Engineering and Computer Sciences

Low leakage current junction-less double gate tunnel field-effect transistor (JLDGTFET) with narrow band gap material pocket region of $Si_{0.7}Ge_{0.3}$ shows increased band to band tunneling and sharp subthreshold characteristics to meet low power, high speed digital and memory applications. The proposed JLDGTFET exploits the junction-less behavior that supports reasonable values of ON/OFF currents as well as improved subthreshold parameters. First, the performance optimization of the JLDGTFET is carried out with different gate contact and oxide region materials in terms of $I_{ON}/I_{OFF}$ current ratio, subthreshold slope, and drain induced barrier lowering. The ON/OFF performance of the pocket $Si_{0.7}Ge_{0.3}$ JLDGTFET with cavity …


Improving The Redundancy Of Knuth?S Balancing Scheme For Packet Transmissionsystems, Elie Ngomseu Mambou, Ebenezer Esenogho, Hendrik Ferreira Jan 2019

Improving The Redundancy Of Knuth?S Balancing Scheme For Packet Transmissionsystems, Elie Ngomseu Mambou, Ebenezer Esenogho, Hendrik Ferreira

Turkish Journal of Electrical Engineering and Computer Sciences

A simple scheme was proposed by Knuth to generate binary balanced code words from any information word. However, this method is limited in the sense that its redundancy is twice that of the full sets of balanced codes. The gap between Knuth?s algorithm?s redundancy and that of the full sets of balanced codes is significantly considerable. This paper attempts to reduce that gap. Furthermore, many constructions assume that a full balancing can be performed without showing the steps. A full balancing refers to the overall balancing of the encoded information together with the prefix. We propose an efficient way to …


A Postpruning Decision Algorithm Based On Loss Minimization, Ahmed M. Ahmed, Ali̇ Hakan Ulusoy, Ahmet Ri̇zaner Jan 2019

A Postpruning Decision Algorithm Based On Loss Minimization, Ahmed M. Ahmed, Ali̇ Hakan Ulusoy, Ahmet Ri̇zaner

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a post-pruning method known as zero-one loss function pruning (ZOLFP) that is based on zero-one loss function is introduced. The proposed ZOLFP method minimizes the expected loss, rather than evaluating the misclassification error rate of a node and its subtree. The subtree is pruned when expected loss of the node is less than or equal to the sum of the loss of its leaves. The experimental results demonstrate that ZOLFP method outperforms. Un-pruned C4.5 Decision Tree (UDT-C4.5) algorithm, reduced error pruning (REP), and minimum error pruning (MEP) in terms of performance accuracy in all used datasets. It …


A Comparative Study Of Nonlinear Bayesian Filtering Algorithms For Estimation Ofgene Expression Time Series Data, Nesrine Amor, Asma Meddeb, Sahbi Marrouchi, Souad Chebbi Jan 2019

A Comparative Study Of Nonlinear Bayesian Filtering Algorithms For Estimation Ofgene Expression Time Series Data, Nesrine Amor, Asma Meddeb, Sahbi Marrouchi, Souad Chebbi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper addresses the problem of estimating the time series of a gene expression using nonlinear Bayesian filtering algorithms. The response of gene regulatory networks (GRNs) to functional requirements in the cell and environmental conditions evolves over time. Dynamic biological processes such as cancer progression and treatment recovery depend on the collected genetic profiles. These processes are behind genetic interactions that rewire over the course of time. The GRN was formulated as a nonlinear and non-Gaussian dynamic system defined by the gene measurement model and the unknown state is an evolution of the gene model. However, the GRN has a …


Early Reliability Assessment Of Component-Based Software System Using Coloredpetri Net, Amir Hosseinzadeh Mokarram, Ayaz Isazadeh, Habib Izadkhah Jan 2019

Early Reliability Assessment Of Component-Based Software System Using Coloredpetri Net, Amir Hosseinzadeh Mokarram, Ayaz Isazadeh, Habib Izadkhah

Turkish Journal of Electrical Engineering and Computer Sciences

Assessment of reliability in the early stages of software development from architectural models is one of the major challenges that many studies have addressed in this field in the last decade. The main drawbacks of existing methods are the following: 1) considering equal impact for all parts of the software architecture on system reliability, and 2) inability to determine the contribution of each part of the software in the system failure. This paper introduces the extended version of the colored petri net as an underlying verifiable model to evaluate the reliability of a software system. The proposed model enhances reliability …


Prioritizing Interdependent Software Requirements Using Tensor And Fuzzy Graphs, Negin Misaghian, Homayun Motameni, Mohsen Rabbani Jan 2019

Prioritizing Interdependent Software Requirements Using Tensor And Fuzzy Graphs, Negin Misaghian, Homayun Motameni, Mohsen Rabbani

Turkish Journal of Electrical Engineering and Computer Sciences

Owing to the special stance of prioritizing tasks in requirements engineering processes, and as the requirements are not independent in nature, considering their dependencies is essential during the prioritizing process. Although different classifications of dependency types among requirements exist, only a few approaches in the prioritization process consider such valuable data (dependency among equirements). To achieve a practical prioritization, this study proposes a method based on the effects of the requirement dependencies (increase/decrease cost of) on the value of prioritization provided by the tensor concept. Since the strengths of dependencies are also influential factors in the act of prioritization, The …


Between-Host Hiv Model: Stability Analysis And Solution Using Memeticcomputing, Musharif Ahmed, Ijaz Mansoor Qureshi, Muhammad Aamer Saleem, Muhammad Zubair, Saad Zafar Jan 2019

Between-Host Hiv Model: Stability Analysis And Solution Using Memeticcomputing, Musharif Ahmed, Ijaz Mansoor Qureshi, Muhammad Aamer Saleem, Muhammad Zubair, Saad Zafar

Turkish Journal of Electrical Engineering and Computer Sciences

HIV poses a great threat to humanity for two major reasons. First it attacks the immunity system of the body and second, it is epidemic in nature. Mathematical models of HIV have been instrumental in understanding and controlling the infection. In this paper, we solve the between host epidemic model of HIV, described by nonlinear coupled differential equations, by using memetic computing. Under this model, the sexually active population is divided into four classes and we investigate the transfer of individuals from one class to another. The solution consists of Bernstein polynomials whose parameters have been optimized by using differential …


Dop: Discover Objects And Paths, A Model For Automated Navigation Andselection In Virtual Environments, Muhammad Raees, Sehat Ullah Jan 2019

Dop: Discover Objects And Paths, A Model For Automated Navigation Andselection In Virtual Environments, Muhammad Raees, Sehat Ullah

Turkish Journal of Electrical Engineering and Computer Sciences

Navigation and selection are the two interaction tasks often needed for the manipulation of an object in a synthetic world. An interface that supports automatic navigation and selection may increase the realism of a virtual reality (VR) system. Such an engrossing interface of a VR system is possible by incorporating machine learning (ML) into the realm of the virtual environment (VE). The use of intelligence in VR systems, however, is a milestone yet to be achieved to make seamless realism in a VE possible. To improve the believability of an intelligent virtual agent (IVA), this research work presents DOP (Discover …


Toxicity Prediction Of Small Drug Molecules Of Aryl Hydrocarbon Receptor Using Aproposed Ensemble Model, Vishan Kumar Gupta, Prashant Singh Rana Jan 2019

Toxicity Prediction Of Small Drug Molecules Of Aryl Hydrocarbon Receptor Using Aproposed Ensemble Model, Vishan Kumar Gupta, Prashant Singh Rana

Turkish Journal of Electrical Engineering and Computer Sciences

Quantitative structure-activity relationships and quantitative structure?property relationships have proved their usefulness for predicting toxicities of drug molecules regarding their biological activities. In silico toxicity prediction techniques are essential for reducing testing on rodents (in vivo) and for a less time-consuming and more cost-efficient alternative for the identification of toxic effects at an early stage of drug development. The authors aim to build a prediction model for better assessment of toxicity to quickly and efficiently test whether certain chemical compounds have the potential to disrupt the processes in the human body that may adversely affect human health. Here, we have proposed …


Extraction And Selection Of Statistical Harmonics Features For Electrical Appliancesidentification Using K-Nn Classifier Combined With Voting Rules Method, Fateh Ghazali, Abdenour Hacine-Gharbi, Philippe Ravier, Tayeb Mohamadi Jan 2019

Extraction And Selection Of Statistical Harmonics Features For Electrical Appliancesidentification Using K-Nn Classifier Combined With Voting Rules Method, Fateh Ghazali, Abdenour Hacine-Gharbi, Philippe Ravier, Tayeb Mohamadi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose a novel framework for electrical appliances identification using statistical harmonic features of current signals and the use of the k-NN classifier combined with a voting rule strategy. Harmonic coefficients are computed over time using short-time Fourier series of the current signals. From these sequences of coefficients, the mean, standard deviation, skewness, and kurtosis are computed, which provide the statistical harmonic features. This framework has three novelties: (i) selecting the best combination of statistical measures in the sense of classification rate (CR); (ii) combining the k-NN classifier with the voting rule method in order to search …


Effect Of Orientation Of Rf Sources Maintained Within The Enclosures On Electricalshielding Effectiveness Performance, İbrahi̇m Bahadir Başyi̇ği̇t, Abdullah Genç, Selçuk Helhel Jan 2019

Effect Of Orientation Of Rf Sources Maintained Within The Enclosures On Electricalshielding Effectiveness Performance, İbrahi̇m Bahadir Başyi̇ği̇t, Abdullah Genç, Selçuk Helhel

Turkish Journal of Electrical Engineering and Computer Sciences

The effect of single aperture metallic enclosures on electrical shielding effectiveness (ESE) has been investigated. Simulations and measurements have been obtained for comparison. The effects of orientation of transmitting antenna (source orientation) with respect to aperture length have been studied at 2.60?9 GHz as a novelty, and this gives details of IC RF source orientation in an enclosure. In the case of square apertures on an enclosure, a higher ESE value is obtained with respect to a rectangular aperture. As a case study, when the aperture width of the enclosure is decreased from 75 to 18.75 mm, the frequency bandwidth …


A Quasi-Z-Source Active Neutral Point Clamped Inverter Topology Employingsymmetrical/Unsymmetrical Boost Modulation Control Scheme For Renewableenergy Resources, Rehan Majeed, Danial Saleem, M. Imtiaz Hussain, Muhammad Talha Gul, Muhammad Rehan Usman, Salman Majeed Jan 2019

A Quasi-Z-Source Active Neutral Point Clamped Inverter Topology Employingsymmetrical/Unsymmetrical Boost Modulation Control Scheme For Renewableenergy Resources, Rehan Majeed, Danial Saleem, M. Imtiaz Hussain, Muhammad Talha Gul, Muhammad Rehan Usman, Salman Majeed

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a bipolar quasi-Z-source active neutral point clamped inverter (QZS-ANPCI) topology. It acts as a buck/boost inverter (3-phase, 3-level) to integrate renewable energy resources under their fluctuating DC voltages. We propose a symmetrical/unsymmetrical boost modulation control technique to mitigate the DC-link unbalance voltage problem in an ANPC inverter. This worthwhile control technique exploits voltage-current closedloops on AC and DC sides to regulate the desired parameters. Moreover, the constant boost control (CBC) modulation has provided a switching sequence that generates a symmetrical/unsymmetrical full shoot-through (FST) state for boosting input DC voltage in the proposed inverter. Detailed loss and efficiency …


Importance-Based Signal Detection And Parameter Estimation With Applications To New Particle Search, Hati̇ce Doğan, Nasuf Sönmez, Güleser Kalayci Demi̇r Jan 2019

Importance-Based Signal Detection And Parameter Estimation With Applications To New Particle Search, Hati̇ce Doğan, Nasuf Sönmez, Güleser Kalayci Demi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

One of the hardest challenges in data analysis is perhaps the detection of rare anomalous data buried in a huge normal background. We study this problem by constructing a novel method, which is a combination of the Kullback?Leibler importance estimation procedure based anomaly detection algorithm and linear discriminant classifier. We choose to illustrate it with the example of charged Higgs boson (CHB) search in particle physics. Indeed, the Large Hadron Collider experiments at CERN ensure that CHB signal must be a tiny effect within the irreducible W-boson background. In simulations, different CHB events with different characteristics are produced and judiciously …


Sensorless Second-Order Switching Surface For A Three-Level Boost Converter, Tarek Messikh, Nasrudin Abd Rahim, Saad Mekhilef Jan 2019

Sensorless Second-Order Switching Surface For A Three-Level Boost Converter, Tarek Messikh, Nasrudin Abd Rahim, Saad Mekhilef

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a sensorless second-order switching surface to control a three-level boost converter (TLBC). A predictive current method is proposed to reduce the number of sensors in the normal second-order switching surface method. Based on a developed model of the TLBC, the current is estimated and a switching surface is formulated in the state-energy plane. Simulation and hardware tests are carried out to verify the viability and the effectiveness of the proposed control technique. Results obtained show a good performance of the converter in term of DC-bus balancing and fast dynamic response under sudden load change.


A Compact Wide-Slot Uwb Antennawith Reconfigurable And Sharp Dual-Band Notches For Underlay Cognitive Radioapplications, Falih Alnahwi, Abdulghafor Abdulhameed, Husham Swadi, Abdulkareem Abdullah Jan 2019

A Compact Wide-Slot Uwb Antennawith Reconfigurable And Sharp Dual-Band Notches For Underlay Cognitive Radioapplications, Falih Alnahwi, Abdulghafor Abdulhameed, Husham Swadi, Abdulkareem Abdullah

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a compact wide-slot ultrawide-band (UWB) antenna with reconfigurable and sharp dual-band notches compatible with the underlay cognitive radio systems. The antenna slot and tuning stub are reshaped in such a way that the proposed antenna operating bandwidth extends along the frequency band specified for UWB applications (3.1-10.6 GHz). In spite of their sharpness, the generated band notches perfectly cancel the interference with the entire 5 GHz wireless local area network (WLAN) frequency band (5.15-5.725 GHz) and that of the military X-band satellite communications downlink (7.25-7.745 GHz). The WLAN band notch is presented by attaching a pair of …


A Developed Flywheel Energy Storage With Built-In Rotating Supercapacitors, Hamidreza Toodeji Jan 2019

A Developed Flywheel Energy Storage With Built-In Rotating Supercapacitors, Hamidreza Toodeji

Turkish Journal of Electrical Engineering and Computer Sciences

Flywheel energy storage can store large amounts of kinetic energy in its rotating parts, but its inertia restricts the rate of power exchange. On the other hand, there is supercapacitor with the ability of exchanging large amounts of instantaneous power. Therefore, the combination of these two systems can significantly improve the dynamic response of conventional flywheel energy storage. This paper proposes a novel design for this combined system in which supercapacitors are located inside the rotating disk. Therefore, supercapacitors can significantly improve the dynamic performance of the flywheel energy storage with trivial effects on its size and weight. Moreover, the …


Power Electronic Controller With Time Sharing Switching Strategy For Grid Connected Pv Systems, Maria Jenisha Charles, Ammasaigounden Nanjappagounder, Binu Ben Jose Dharmaian Retnam Jan 2019

Power Electronic Controller With Time Sharing Switching Strategy For Grid Connected Pv Systems, Maria Jenisha Charles, Ammasaigounden Nanjappagounder, Binu Ben Jose Dharmaian Retnam

Turkish Journal of Electrical Engineering and Computer Sciences

The design and implementation of a high-efficiency two-stage power electronic controller for feeding power from a photovoltaic (PV) array to the load/utility grid is proposed. The PV array is connected to the load/utility grid through a boost converter and an inverter. The boost converter is controlled by sinusoidal pulse width modulation (SPWM) pulses so as to get a clamped quasi-sinusoidal waveform at the DC link. The inverter converts the clamped quasi-DC voltage into AC voltage using the SPWM controller. At any time only one switch operates at high frequency, thus yielding reduction in the switching losses of the converters. The …


Efficient Virtual Data Center Request Embedding Based On Row-Epitaxial And Batched Greedy Algorithms, Sivaranjani B, Surendran Doraiswamy Jan 2019

Efficient Virtual Data Center Request Embedding Based On Row-Epitaxial And Batched Greedy Algorithms, Sivaranjani B, Surendran Doraiswamy

Turkish Journal of Electrical Engineering and Computer Sciences

Data centers are becoming the main backbone of and centralized repository for all cloud-accessible services in on-demand cloud computing environments. In particular, virtual data centers (VDCs) facilitate the virtualization of all data center resources such as computing, memory, storage, and networking equipment as a single unit. It is necessary to use the data center efficiently to improve its profitability. The essential factor that significantly influences efficiency is the average number of VDC requests serviced by the infrastructure provider, and the optimal allocation of requests improves the acceptance rate. In existing VDC request embedding algorithms, data center performance factors such as …


Optimal Range Of Loading For Operating A Fixed-Speed Wind Turbine Using A Self-Excited Induction Generator, Nassi̇m Iqteit, Gül Kurt, Beki̇r Çakir Jan 2019

Optimal Range Of Loading For Operating A Fixed-Speed Wind Turbine Using A Self-Excited Induction Generator, Nassi̇m Iqteit, Gül Kurt, Beki̇r Çakir

Turkish Journal of Electrical Engineering and Computer Sciences

In the present study, a new strategy of analysis was used to determine the optimal interval of a single-phase resistive load to operate a fixed-speed wind turbine. The essence of this optimal range is to enable the generator to have stable voltages and current balances, large power, and an acceptable frequency range, and also mitigate generator overheating. The generator windings and excitation capacitances were prepared according to the C-2C connection scheme with suitable values of excitation capacitances. The admittance matrix of the system was based on positive and negative sequence generator voltages and was calculated by symmetrical components theory. The …


Tapu: Test And Pick Up-Based $K$-Connectivity Restoration Algorithm For Wireless Sensor Networks, Vahi̇d Khali̇lpour Akram, Orhan Dağdevi̇ren Jan 2019

Tapu: Test And Pick Up-Based $K$-Connectivity Restoration Algorithm For Wireless Sensor Networks, Vahi̇d Khali̇lpour Akram, Orhan Dağdevi̇ren

Turkish Journal of Electrical Engineering and Computer Sciences

A $k$-connected wireless sensor network remains connected if any $k$-1 arbitrary nodes stop working. The aim of movement-assisted $k$-connectivity restoration is to preserve the $k$-connectivity of a network by moving the nodes to the necessary positions after possible failures in nodes. This paper proposes an algorithm named TAPU for $k$-connectivity restoration that guarantees the optimal movement cost. Our algorithm improves the time and space complexities of the previous approach (MCCR) in both best and worst cases. In the proposed algorithm, the nodes are classified into safe and unsafe groups. Failures of safe nodes do not change the $k$ value of …


Probabilistic Small-Signal Stability Analysis Of Power System With Solar Farm Integration, Samundra Gurung, Sumate Naetiladdanon, Anawach Sangswang Jan 2019

Probabilistic Small-Signal Stability Analysis Of Power System With Solar Farm Integration, Samundra Gurung, Sumate Naetiladdanon, Anawach Sangswang

Turkish Journal of Electrical Engineering and Computer Sciences

Currently, large-scale solar farms are being rapidly integrated in electrical grids all over the world. However, the photovoltaic (PV) output power is highly intermittent in nature and can also be correlated with other solar farms located at different places. Moreover, the increasing PV penetration also results in large solar forecast error and its impact on power system stability should be estimated. The effects of these quantities on small-signal stability are difficult to quantify using deterministic techniques but can be conveniently estimated using probabilistic methods. For this purpose, the authors have developed a method of probabilistic analysis based on combined cumulant …


A Joint Image Dehazing And Segmentation Model, Haider Ali, Awal Sher, Nosheen Zikria, Lavdi̇e Rada Ülgen Jan 2019

A Joint Image Dehazing And Segmentation Model, Haider Ali, Awal Sher, Nosheen Zikria, Lavdi̇e Rada Ülgen

Turkish Journal of Electrical Engineering and Computer Sciences

Objects and their feature identification in hazy or foggy weather conditions has been of interest in the last decades. Improving image visualization by removing weather influence factors for easy image postprocessing, such as object detection, has benefits for human assistance systems. In this paper, we propose a novel variational model that will be capable of jointly segmenting and dehazing a given image. The proposed model incorporates atmospheric veil estimation and locally computed denoising constrained surfaces into a level set function by performing a robust and efficient image dehazing and segmentation scheme for both gray and color outdoor images. The proposed …


A Beaconing-Based Roadside Services Discovery Protocol For Vehicular Ad Hoc Networks, Kifayat Ullah, Ali Sayyed, Muhammad Aziz, Edson Moreira Jan 2019

A Beaconing-Based Roadside Services Discovery Protocol For Vehicular Ad Hoc Networks, Kifayat Ullah, Ali Sayyed, Muhammad Aziz, Edson Moreira

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, research on vehicular ad hoc networks (VANETs) has gained momentum all over the world. These emerging networks promise to make our driving experience more efficient, safer, comfortable, and enjoyable. VANETs have the potential to support a wide range of interesting applications. One such promising application area is the discovery of roadside services on the highways. Drivers need an efficient way to find these services during their journeys. However, due to the unique features of VANETs, the design and implementation of such applications is a challenging task. In this paper, we propose an application layer beaconing-based roadside services discovery protocol …


Energy And Economic Assessment Of Major Free Cooling Retrofits For Data Centers In Turkey, Ozan Gözcü, Hamza Sali̇h Erden Jan 2019

Energy And Economic Assessment Of Major Free Cooling Retrofits For Data Centers In Turkey, Ozan Gözcü, Hamza Sali̇h Erden

Turkish Journal of Electrical Engineering and Computer Sciences

Mechanical cooling is responsible for a significant fraction of the energy consumption of data centers (DCs). Free cooling systems take advantage of ambient conditions to reduce the need for compressor-based cooling. This study utilizes thermodynamic models of major free cooling systems such as the direct air-side economizer (ASE), indirect air-side economizer (IASE), indirect evaporative cooler (IEC), and indirect water-side economizer (WSE) integrated with the existing cooling infrastructure of a typical 1 MW IT load DC. Proposed models utilize hourly weather data of various cities in Turkey to compute annual energy consumption and cost-saving potentials of each free cooling method with …


A Hybrid Single-Source Shortest Path Algorithm, Hi̇lal Arslan, Murat Manguoğlu Jan 2019

A Hybrid Single-Source Shortest Path Algorithm, Hi̇lal Arslan, Murat Manguoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

The single-source shortest path problem arises in many applications, such as roads, social applications, and computer networks. Finding the shortest path is challenging, especially for graphs that contain a large number of vertices and edges. In this work, we propose a novel hybrid method that first sparsifies a given graph by removing most edges that cannot form the shortest path tree and then applies a classical shortest path algorithm to the sparser graph. Removing all the edges that cannot form the shortest path tree would be expensive since it is equivalent to solving the original problem. Therefore, we propose an …


Modified Self-Adaptive Local Search Algorithm For A Biobjective Permutation Flowshop Scheduling Problem, Çi̇ğdem Alabaş Uslu, Berna Dengi̇z, Canan Ağlan, İhsan Sabuncuoğlu Jan 2019

Modified Self-Adaptive Local Search Algorithm For A Biobjective Permutation Flowshop Scheduling Problem, Çi̇ğdem Alabaş Uslu, Berna Dengi̇z, Canan Ağlan, İhsan Sabuncuoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Interest in multiobjective permutation flow shop scheduling (PFSS) has increased in the last decade to ensure effective resource utilization. This study presents a modified self-adaptive local search (MSALS) algorithm for the biobjective permutation flow shop scheduling problem where both makespan and total flow time objectives are minimized. Compared to existing sophisticated heuristic algorithms, MSALS is quite simple to apply to different biobjective PFSS instances without requiring effort or time for parameter tuning. Computational experiments showed that MSALS is either superior to current heuristics for Pareto sets or is incomparable due to other performance indicators of multiobjective problems.


Energy-Efficient Scheduling For Real-Time Tasks Using Dynamic Slack Reclamation, Vasanthamani Kannaian, Visalakshi Palanisamy Jan 2019

Energy-Efficient Scheduling For Real-Time Tasks Using Dynamic Slack Reclamation, Vasanthamani Kannaian, Visalakshi Palanisamy

Turkish Journal of Electrical Engineering and Computer Sciences

The application domains of portable embedded real-time systems range from safety-critical applications like electronic control units in the automotive sector to entertainment applications like digital cameras and setup boxes in the consumer electronics sector. These systems attract users with multiple and sophisticated functionalities in a single system. The developments in VLSI technology have enabled IC manufacturers to incorporate more features in a single die, which facilitates these multipurpose systems. The increase in features and functionalities has a direct impact on power consumption and has to be strictly accounted for in the design of these embedded systems. The possibility of achieving …