Computer Engineering Commons^™

A Hierarchical Architectural Framework For Securing Unmanned Aerial Systems, Matthew Leccadito

Theses and Dissertations

Unmanned Aerial Systems (UAS) are becoming more widely used in the new era of evolving technology; increasing performance while decreasing size, weight, and cost. A UAS equipped with a Flight Control System (FCS) that can be used to fly semi- or fully-autonomous is a prime example of a Cyber Physical and Safety Critical system. Current Cyber-Physical defenses against malicious attacks are structured around security standards for best practices involving the development of protocols and the digital software implementation. Thus far, few attempts have been made to embed security into the architecture of the system considering security as a holistic problem. …

Collaboration In Virtual Worlds: Impact Of Task Complexity On Team Trust And Satisfaction, Fiona Fui-Hoon Nah, Shu Schiller, Brian E. Mennecke, Keng Siau

Research Collection School Of Computing and Information Systems

Virtual worlds are three-dimensional, computer-generated worlds in which team collaboration can be facilitated through the use of shared virtual space and mediated using avatars. This article examines the effect of task complexity on team collaboration. A puzzle game in Second Life was used as the collaborative task and task complexity was manipulated by varying the number of pieces in the puzzle. The hypotheses are that task complexity influences team trust, and team trust influences team process satisfaction in virtual team collaboration. The experimental results indicate that task complexity has significant effects on team trust and team process satisfaction, and team …

Improving The Performance And Time-Predictability Of Gpus, Yijie Huangfu

Theses and Dissertations

Graphic Processing Units (GPUs) are originally mainly designed to accelerate graphic applications. Now the capability of GPUs to accelerate applications that can be parallelized into a massive number of threads makes GPUs the ideal accelerator for boosting the performance of such kind of general-purpose applications. Meanwhile it is also very promising to apply GPUs to embedded and real-time applications as well, where high throughput and intensive computation are also needed.

However, due to the different architecture and programming model of GPUs, how to fully utilize the advanced architectural features of GPUs to boost the performance and how to analyze the …

A High Performance Hysteresis Current Control Of A Permanent Magnet Synchronous Motor Drive, Cosmas Ogbuka, Cajethan Nwosu, Marcel Agu

Turkish Journal of Electrical Engineering and Computer Sciences

A high performance hysteresis current control of a permanent magnet synchronous motor (PMSM) drive is developed in this paper. The core advantage of field orientation control (FOC) is utilized to separate the flux and torque control components of the stator current of the PMSM. Specifically, the objectives of this work are to develop and utilize the HCC algorithm for FOC of a complete closed-loop speed-controlled PMSM drive system, optimize the control algorithm to obtain fast speed response while maintaining effective current and torque tracking, and examine the hysteresis current control action clearly showing the inverter switching and the effects of …

A New Approach For Optimal Reactive Power Flow Of Mtdc Systems Using The Abc Algorithm, Ulaş Kiliç, Kürşat Ayan

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new approach to optimize reactive power flow of multiterminal high voltage direct current (HVDC) systems. Successful application of two-terminal DC systems worldwide makes the use of multiterminal direct current (MTDC) systems more attractive. Due to the economic and technical advantages of HVDC technology, MTDC systems have been used extensively in recent years. In this study, the artificial bee colony (ABC) algorithm is used for solution of the optimal reactive power flow problem of MTDC systems. In opposition to the current-balancing method used in the literature, this study represents a new approach for DC system power flow …

Naive Forecasting Of Household Natural Gas Consumption With Sliding Window Approach, Mustafa Akpinar, Nejat Yumuşak

Turkish Journal of Electrical Engineering and Computer Sciences

Household consumption has a significant importance for natural gas wholesale companies. These companies make one-day-ahead forecasting daily. However, there are penalties depending on the error of the estimates. These penalties increase exponentially depending on the error rate. Several studies have been done to develop mathematical models to forecast natural gas consumption and minimize the error rate. However, before mathematical model predictions, a previous step, data preparation, is also important. The data must be prepared correctly before the mathematical model. At this point, prior to the mathematical model, selecting the appropriate data set size has a vital role. In this study, …

Comparison Of Group Key Establishment Protocols, Serap Şahi̇n, Rabi̇a Aslanoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Recently group-oriented applications over unsecure open networks such as Internet or wireless networks have become very popular. Thus, group communication security over unsecure open networks has become a vital concern. Group key establishment (GKE) protocols are used to satisfy the confidentiality requirement of a newly started communication session by the generation or sharing of an ephemeral common key between the group members. In this study, we analyze the computation and communication efficiency of GKE protocols. Besides confidentiality, the security characteristics of identification and integrity control are also required for all steps of the protocol implementations. Thus, the main contribution of …

A Game-Theoretic Framework For Active Distribution Network Planning To Benefit Different Participants Under The Electricity Market, Bo Zeng, Jinyue Shi, Junqiang Wen, Jianhua Zhang

Turkish Journal of Electrical Engineering and Computer Sciences

With the deregulation of the power sector, distribution system planning is transforming from the traditional integrated decision mode to the multiple-player-based decentralized paradigm. However, this could potentially cause an adverse impact on the performance of the system due to interest conflict of market players during operations. To address such an issue, this paper develops a game-theoretic framework for active distribution network planning under the electricity market. The interplay between the distribution utility (DISCO) and distributed generation investors (DGO) is formulated as a noncooperative, two-person-based Stackelberg game in which the DISCO, as the leader of the game, makes expansion of the …

Unknown Input Observer Based On Lmi For Robust Generation Residuals, Souad Tahraoui, Abdelmadjid Meghabbar, Djamila Boubekeur

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a method of generating robust residuals of a linear system, subject to unknown inputs, is proposed. The impact of disturbances and uncertainty may create difficulties at the decision stage of diagnosis (false alarm); this has resulted in the use of a robust observer for the unknown inputs to ensure the robustness of the system based on the unknown input observer with an optimal decoupling approach, which has a sensitivity that is minimal to unknown inputs and maximal to faults. A generation of robust residuals is then transformed into a problem of robustness/sensitivity constraints (H$_{\infty }$, H and …

Dtreesim: A New Approach To Compute Decision Tree Similarity Using Re-Mining, Gözde Bakirli, Derya Bi̇rant

Turkish Journal of Electrical Engineering and Computer Sciences

A number of recent studies have used a decision tree approach as a data mining technique; some of them needed to evaluate the similarity of decision trees to compare the knowledge reflected in different trees or datasets. There have been multiple perspectives and multiple calculation techniques to measure the similarity of two decision trees, such as using a simple formula or an entropy measure. The main objective of this study is to compute the similarity of decision trees using data mining techniques. This study proposes DTreeSim, a new approach that applies multiple data mining techniques (classification, sequential pattern mining, and …

Robust Adaptive Fuzzy Control Of A Three-Phase Active Power Filter Based On Feedback Linearization, Shixi Hou, Juntao Fei

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a robust adaptive fuzzy control system using feedback linearization is proposed for a three-phase active power filter (APF). The APF system is divided into two separate loops: the current dynamic inner loop and the DC voltage dynamic outer loop. Adaptive fuzzy tracking control using feedback linearization is employed for the current dynamic inner loop to overcome the drawbacks of the conventional method. The proposed controller can ensure proper tracking of the reference current and impose desired dynamic behavior, giving robustness and insensitivity to parameter variations. Adaptive fuzzy proportional-integral control is applied to the DC voltage dynamics outer …

Periodic Control For The Cart Pendulum System With Structured Uncertainty, Arindam Chakraborty, Jayati Dey

Turkish Journal of Electrical Engineering and Computer Sciences

The robust stabilization of the cart pendulum system was studied under structured uncertainty with a continuous-time periodic controller. The cart pendulum system was considered here as the test set-up as it is a well-known example of an unstable nonminimum phase system. The uncertainty in the system rose due to measurement error or dry friction in it. In this paper, the robust stability of the periodic controller in the presence of uncertainty was examined. The gain margin and delay margin endow with the periodic controller were superior to those obtained in the case of linear time invariant (LTI) control even in …

Low Power 3rd Order Feedforward Sigma Delta Adc Design, Feyyaz Meli̇h Akçakaya, Günhan Dündar

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a 3-bit feedforward 3rd order sigma delta analog-to-digital converter (ADC) is presented. In this proposed architecture, feedforward paths and multibit design help the integrator output swings to become smaller, which renders the exploitation of a telescopic cascode opamp in the integrators possible. Moreover, a double sampling method is used to relax the opamp specifications. The proposed sigma delta ADC consumes 28.2 $\mu $W and has 81.3 dB SNDR according to postlayout simulations.

A Multifunctional Dstatcom For Power Quality Improvement, Mohammad Mahdianpoor, Arash Kiyoumarsi, Mohammad Ataei, Rahmat Allah Hooshmand, Houshang Karimi

Turkish Journal of Electrical Engineering and Computer Sciences

The distribution static compensator (DSTATCOM) is used for various purposes such as load balancing, harmonic rejection, and power factor correction (PFC) in power distribution networks. In unbalanced and polluted power systems, the classic definition of power factor cannot be used for PFC due to the existence of harmonics and negative sequence components in voltage and current waveforms. In this paper, PFC is performed using the IEEE power factor definition for harmonic and unbalanced environments. Moreover, the application of a proportional-resonant (PR) controller is proposed as an effective controller in the stationary frame for DSTATCOM performance improvement. The PR controller is …

Gica: Imperialist Competitive Algorithm With Globalization Mechanism For Optimization Problems, Yousef Abdi, Mahmoud Lak, Yousef Seyfari

Turkish Journal of Electrical Engineering and Computer Sciences

The imperialist competitive algorithm (ICA) is a recent global search strategy developed based on human social evolutionary phenomena in the real world. However, the ICA has the drawback of trapping in local optimum solutions when used for high-dimensional or complex multimodal functions. In order to deal with this situation, in this paper an improved ICA, named GICA, is proposed that can enhance ICA performance by using a new assimilation method and establishing a relationship between countries inspired by the globalization concept in the real world. The proposed algorithm is evaluated using a set of well-known benchmark functions for global optimization. …

Novel Scheduling Algorithm For Optimizing Real-Time Multimedia Performance In Long Term Evolution-Advanced, Huda Adibah Mohd Ramli, Zairi Ismael Rizman

Turkish Journal of Electrical Engineering and Computer Sciences

Real-time multimedia applications are becoming increasingly popular among mobile cellular users. Given that Long Term Evolution-Advanced (LTE-A), which is an emerging mobile cellular standard, needs to support these multimedia applications, packet scheduling is of paramount importance in LTE-A. This paper proposes a packet scheduling algorithm known as novel scheduling for usage in the downlink of LTE-A. It takes channel quality, average throughput, and packet delay into account when determining the priority of each user. Simulation results demonstrate the efficacy of the proposed algorithm in optimizing real-time multimedia performance for more mobile cellular users.

Application Of Singular Value Decomposition Algorithm For Implementing Power Amplifier Linearizer, Rajbir Kaur, Manjeet Singh Patterh

Turkish Journal of Electrical Engineering and Computer Sciences

A power amplifier (PA) is an integral component of all base stations in wireless communication systems and is used for converting DC power supply into radio frequency output power, but PAs are highly nonlinear. To achieve high power conversion efficiency, the PA is operated near saturation, which causes intermodulation products and hence results in nonlinear distortion. Digital predistortion (DPD) is a technique used to compensate for the nonlinear distortion without compromising its efficiency. Fourth Generation Long Term Evolution (4G LTE) systems use a carrier aggregation scheme to combine separate available bandwidths to deliver high data speeds. In this paper the …

Minimizing Scheduling Overhead In Lre-Tl Real-Time Multiprocessor Scheduling Algorithm, Hitham Seddig Alhassan Alhussian, Mohamed Nordin Bin Zakaria, Fawnizu Azmadi Bin Hussin

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a modification of the local remaining execution-time and local time domain (LRE-TL) real-time multiprocessor scheduling algorithm, aimed at reducing the scheduling overhead in terms of task migrations. LRE-TL achieves optimality by employing the fairness rule at the end of each time slice in a fluid schedule model. LRE-TL makes scheduling decisions using two scheduling events. The bottom (B) event, which occurs when a task consumes its local utilization, has to be preempted in order to resume the execution of another task, if any, or to idle the processor if none exist. The critical (C) event …

Sotarm: Size Of Transaction-Based Association Rule Mining Algorithm, Asha Pandian, Jebarajan Thaveethu

Turkish Journal of Electrical Engineering and Computer Sciences

Mining of association rules tries to identify the existence of promising and fruitful relations among the items present in a database. The basic a priori algorithm suffers from multiple database scans, and if the database is large, then the time taken for scanning and generation of candidates is also large. The proposed algorithm attempts to reduce the repeated scanning of the whole database. Using this algorithm, scanning time and also the generation of subitems that are not frequent can be reduced. The former can be done by sorting the transaction records in descending order based on the size of transaction …

Exploiting Kernel-Based Feature Weighting And Instance Clustering To Transfer Knowledge Across Domains, Jafar Tahmoresnezhad, Sattar Hashemi

Turkish Journal of Electrical Engineering and Computer Sciences

Learning invariant features across domains is of vital importance to unsupervised domain adaptation, where classifiers trained on the training examples (source domain) need to adapt to a different set of test examples (target domain) in which no labeled examples are available. In this paper, we propose a novel approach to find the invariant features in the original space and transfer the knowledge across domains. We extract invariant features of input data by a kernel-based feature weighting approach, which exploits distribution difference and instance clustering to find desired features. The proposed method is called the kernel-based feature weighting (KFW) approach and …

A Symmetrically Feeding Structure For Dual-Polarized Feeds, Jinyuan Liu, Hui Deng, Bin Ding, Xiaolong Niu

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a symmetrically feeding structure for linear dual-polarized feeds for a compensated compact test range (CCR) and a corresponding wideband balun are put forward. $TM_{01}$ and $TE_{21} $ modes within the circular feeding waveguide are compressed due to its electrical balance. The polarization purity of feeds is then improved. Thus, the level of cross-polarization can be very low, which is the key requirement for CCR. A new wideband balun that acts as a power-divider and phase shifter with low amplitude unbalance and phase unbalance is designed for the new feeding structure. The return loss equation derived from an …

Implementation Of Zero Voltage Switched Sepic/Zeta Bidirectional Converter For Low Power Applications Using Fpga, Venmathi Mahendran, Ramaprabha Ramabadran

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a derived SEPIC/ZETA bidirectional converter (BDC) with reduced ripple in the noninverted output voltage. This converter is obtained by the fusion of unidirectional SEPIC and ZETA converters that ensures reduced ripple in the inductor currents. The optimal selection of duty ratio enables the proposed converter to operate either in SEPIC or ZETA mode under forward and reverse power flow. The presence of auxiliary circuit not only reduces the voltage stress on the switches by operating under zero voltage switching condition but also provides isolation between the input and the output ports. The operational principle and the stability …

A Hybrid Maco And Bfoa Algorithm For Power Loss Minimization And Total Cost Reduction In Distribution Systems, Muthubalaji Sankaramoorthy, Malathi Veluchamy

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a multiobjective optimization methodology to optimally place a STATCOM in electric power distribution networks. The combination of multiobjective ant colony optimization (MACO) and the bacterial foraging optimization algorithm (BFOA) is proposed to minimize the power loss and total cost. The main intention of this analysis is to optimally place the STATCOM at multiple locations such as the transmission side, middle, and load side. Identifying the type and location of the STATCOM is a combinatorial optimization problem in power systems. In order to overcome this problem, the combination of hybrid MACO and BFOA algorithms is applied in this …

Pixel- Versus Object-Based Classification Of Forest And Agricultural Areas From Multiresolution Satellite Images, Di̇jle Boyaci, Mustafa Erdoğan, Ferruh Yildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Managing of natural resources including agriculture and forestry is a very important subject for governments and decision makers. Up-to-date, accurate, and timely geospatial information about natural resources is needed in the management process. Remote sensing technology plays a significant role in the production of this geospatial information. Compared to terrestrial work, the analysis of larger areas with remote sensing techniques can be done on a shorter timescale and at lower cost. Image classification in remote sensing is one of the most popular methods used for the detection of forest and agricultural areas. However, the accuracy of classification changes according to …

A Measurement Study Of Internet Exchange Points (Ixps): History And Future Prediction, Mohammad Masoud, Yousef Jaradat, Ismael Jannoud

Turkish Journal of Electrical Engineering and Computer Sciences

Internet exchange points (IXPs) emerged to remedy the deficiency of peering connections among autonomous systems (ASes). IXPs play an important role in reducing the cost of transit connections over the Internet. This work attempts to study the popularity of IXPs over the Internet. This work consists of two main parts. The first part is a measurement study of multihistorical snapshots of IXPs. These historical data have been harvested for different European IXPs with emphasis on Amsterdam (AMS-IX) IXP. In the second part, two nonlinear autoregressive exogenous (NARX) back-propagation neural network models (BPNN) have been implemented to predict the following: the …

An Intelligent Approach In Delay Tolerant Network Routing, Azadeh Omidvar, Karim Mohammadi

Turkish Journal of Electrical Engineering and Computer Sciences

Delay tolerant networks (DTNs) are wireless intermittent networks. DTNs have different applications such as wildlife tracking, military, and space searching. Conventional mobile ad hoc network (MANET) routing protocols are not efficient in these networks because of intermittency. DTNs use store-carry-forward (SCF) for data transferring. In SCF, nodes store the messages and carry them until finding appropriate nodes for forwarding. Message replication greatly helps to improve the delivery ratio while increasing overhead. This paper examines the use of intelligent routing to choose nodes that have more probability to reach their destination. This will help to increase the message delivery ratio while …

Protection Coordination For A Distribution System In The Presence Of Distributed Generation, Muhammad Yousaf, Tahir Mahmood

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes an effective strategy to overcome the impacts on coordination among protection devices due to distributed generator (DG) integration. Increased fault current magnitude and changes in power flow directions are the major impacts imposed by DGs on a typical distribution system. The recloser-fuse coordination is much influenced upon the integration of DGs. The proposed approach presents the rehabilitation of recloser-fuse coordination for post-DG integration effects using the directional properties of a recloser. The simulation results show that coordination among protection devices can be regained using fast operation of the recloser to design a fuse saving scheme in the …

Implementation Of Svc Based On Grey Theory And Fuzzy Logic To Improve Lvrt Capability Of Wind Distributed Generations, Mohammad Mehdi Karami, Akbar Itami

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the great absorption of reactive power after voltage drops caused by faults in network, the low-voltage ride through (LVRT) capability of squirrel cage induction generators (SCIGs) in wind farms is a great challenge. If a static VAR compensator (SVC) is installed at the point of common coupling (PCC) of a wind farm with a main network, it can improve the wind generation's LVRT capability with reactive power compensation. In the voltage control loop of a conventional SVC, the voltage actual value of the PCC is compared with the reference voltage value. This paper presents a method for implementation …

Probabilistic Data Fusion Model For Heart Beat Detection From Multimodal Physiological Data, Tehseen Zia, Zulqarnian Arif

Turkish Journal of Electrical Engineering and Computer Sciences

Automatic detection of heart beats constitutes the basis for electrocardiogram (ECG) analysis and mainly relies on detecting QRS complexes. Detection is typically performed by analyzing the ECG signal. However, when signal quality is low, it often leads to the triggering of false alarms. A contemporary approach to reduce false alarm rate is to use multimodal data such as arterial blood pressure (ABP) or photoplethysmogram (PPG) signals. To leverage the correlated temporal nature of these signals, a probabilistic data fusion model for heart beat detection is proposed. A hidden Markov model is used to decode waveforms into segments. A Bayesian network …

A New Efficient Block Matching Data Hiding Method Based On Scanning Order Selection In Medical Images, Turgay Aydoğan, Cüneyt Bayilmiş

Turkish Journal of Electrical Engineering and Computer Sciences

Digital technology and the widespread use of the Internet has increased the speeds at which digital data can be obtained and shared in daily life. In parallel to this, there are important concerns regarding the confidentiality of private data during data transmissions and the possibility that data might fall into the hands of third parties. Issues relating to data safety can also affect patients' medical images and other information relating to these images. In this study, we propose a new method based on block matching that can be used to hide the patient information in medical images. In this method, …