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Full-Text Articles in Physical Sciences and Mathematics

A Novel Dtc-Svm Approach For Two Parallel-Connected Induction Motors Fed By Matrix Converter, Mahdi Jafari, Karim Abbaszadeh, Mustafa Mohamadian Jan 2018

A Novel Dtc-Svm Approach For Two Parallel-Connected Induction Motors Fed By Matrix Converter, Mahdi Jafari, Karim Abbaszadeh, Mustafa Mohamadian

Turkish Journal of Electrical Engineering and Computer Sciences

AC machines fed by a single inverter are widely used in industries such as railroad electrification systems where speed synchronization does not have to be exact. The low cost and volume and the small number of power electronic components are attractive aspects of single-inverter multi-motor systems. This paper proposes a novel approach to controlling the speed and torque of two induction motors connected in parallel and fed by a matrix converter under unbalanced load condition. This single-inverter dual-motor (SIDM) drive uses average and differential values of speed and torque together with stator and rotor flux parameters based on the flux …


An Efficient Ofdm-Based System With An Insufficient Cyclic Prefix Via A Novel Constellation Algorithm, Saeed Ghazi-Maghrebi Jan 2017

An Efficient Ofdm-Based System With An Insufficient Cyclic Prefix Via A Novel Constellation Algorithm, Saeed Ghazi-Maghrebi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new special triangular constellation scheme is introduced to replace the commonly used rectangular QAM constellation in orthogonal frequency division multiplexing (OFDM) modulation. We have shown that this new scheme has 3 major advantages with respect to the well-known QAM. The first advantage is its lower error probability performance, which results from better usage of the constellation space with longer minimum distances. The 2 other advantages are a lower peak to average power ratio (PAPR) and higher noise immunity. Both mathematical analysis and simulation results demonstrate that by applying standard channels in 2 cases, i.e. channels with …


An Area-Efficient And Wide-Range Digital Dll For Per-Pin Deskew Applications, Chingche Chung, Chienying Yu Jan 2017

An Area-Efficient And Wide-Range Digital Dll For Per-Pin Deskew Applications, Chingche Chung, Chienying Yu

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, we present a 200 MHz to 1.6 GHz digital delay-locked loop (DLL) for per-pin deskew applications. The proposed phase shifters apply linear and scalable circuit architecture for the pin-to-pin delay mismatch of parallel I/O pins. The proposed phase detector with a detection window and the proposed consecutive phase decision method reduce the sensitivity to reference clock jitter. A test chip of the 0.042 mm$^{2}$ DLL and the 3-ps-adjustable-resolution phase shifters with a 0.0025 mm$^{2}$ per-channel area was implemented using a 90-nm CMOS process. Simulation results show that the phase error of the 90$^{\circ}$ phase shifter at 1.6 …


Performance Enhancement Of A Dynamic Voltage Restorer, Latha Pappath Vasudevan, Valsalal Prasad Jan 2017

Performance Enhancement Of A Dynamic Voltage Restorer, Latha Pappath Vasudevan, Valsalal Prasad

Turkish Journal of Electrical Engineering and Computer Sciences

Custom power devices are widely employed to mitigate power quality issues affecting critical loads. The dynamic voltage restorer is one of the custom power devices designed to inject a voltage in series with line to present a pure sinusoidal voltage of the desired RMS value to the sensitive loads, if the supply side is affected by voltage disturbances. The design and implementation of a DVR with a quasi-impedance source inverter and variable structure control is discussed in this paper. The voltage boosting ability of a quasi-impedance (Z) source inverter is used here to improve the performance of the DVR with …


A 0.65-1.35 Ghz Synthesizable All-Digital Phase Locked Loop With Quantization Noise Suppressing Time-To-Digital Converter, Yalçin Balcioğlu, Günhan Dündar Jan 2017

A 0.65-1.35 Ghz Synthesizable All-Digital Phase Locked Loop With Quantization Noise Suppressing Time-To-Digital Converter, Yalçin Balcioğlu, Günhan Dündar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new quantization noise suppression method for a time-to-digital converter (TDC) and proposes an all-digital phase-locked loop (ADPLL) architecture using only standard cell logic gates. Using a new multiple input multiple output (MIMO) quantization noise suppression method provides an order of $\sqrt {2N} $ improvement in TDC resolution with $N$ parallel TDC channels. Suppressed noise in the TDC allows the ADPLL to achieve superior jitter performance in both theoretical calculations and simulation results. In order to allow fast portability between process nodes, short design cycle time, ease of modification, and flexibility, ADPLL architecture is designed completely in …


Analysis Of Feature Detector And Descriptor Combinations With A Localization Experiment For Various Performance Metrics, Ertuğrul Bayraktar, Pinar Boyraz Jan 2017

Analysis Of Feature Detector And Descriptor Combinations With A Localization Experiment For Various Performance Metrics, Ertuğrul Bayraktar, Pinar Boyraz

Turkish Journal of Electrical Engineering and Computer Sciences

The purpose of this study is to provide a detailed performance comparison of feature detector/descriptor methods, particularly when their various combinations are used for image-matching. The localization experiments of a mobile robot in an indoor environment are presented as a case study. In these experiments, 3090 query images and 127 dataset images were used. This study includes five methods for feature detectors (features from accelerated segment test (FAST), oriented FAST and rotated binary robust independent elementary features (BRIEF) (ORB), speeded-up robust features (SURF), scale invariant feature transform (SIFT), and binary robust invariant scalable keypoints (BRISK)) and five other methods for …


Design And Implementation Of A Six-Port Junction Based On Substrate Integrated Waveguide, Masoud Jafari, Gholamreza Moradi, Reza Sarraf Shirazi, Rashid Mirzavand Jan 2017

Design And Implementation Of A Six-Port Junction Based On Substrate Integrated Waveguide, Masoud Jafari, Gholamreza Moradi, Reza Sarraf Shirazi, Rashid Mirzavand

Turkish Journal of Electrical Engineering and Computer Sciences

A six-port junction based on substrate integrated waveguide technology with high reliability and efficient performance is proposed in a sub-K-band of 21-23.5 GHz. This substrate integrated waveguide (SIW) six-port junction is constructed from three directional couplers and one T-junction power divider as fundamental components in SIW form, where using appropriate via techniques led to -6 dB coupling coefficients and -15 dB return loss. There is good agreement between the simulation and the measurement results.


Trnsys Simulation Of Solar Chimney Power Plants With A Heat Storage Layer, Fei̇ Cao, Yufei Mao, Tianyu Zhu, Liang Zhao Jan 2017

Trnsys Simulation Of Solar Chimney Power Plants With A Heat Storage Layer, Fei̇ Cao, Yufei Mao, Tianyu Zhu, Liang Zhao

Turkish Journal of Electrical Engineering and Computer Sciences

The transient performance of a solar chimney power plant (SCPP) with a heat storage layer is evaluated in the present study. A modified TRNSYS type is built. The ground temperature, wind velocity at the chimney inlet, and the power capacity over two typical days are simulated and compared with and without considering the heat storage layer. SCPP performances with six ground materials (granite, limestone, sandstone, sand, wet soil, and water) are compared. The parameters are postponed for 2-3 h when the heat storage layer is considered. This is the multieffect of solar irradiation, air characteristics, and ambient temperature. The SCPP …


A Parametric Battery State Of Health Estimation Method For Electric Vehicle Applications, Türev Sarikurt, Murat Ceylan, Abdulkadi̇r Balikçi Jan 2017

A Parametric Battery State Of Health Estimation Method For Electric Vehicle Applications, Türev Sarikurt, Murat Ceylan, Abdulkadi̇r Balikçi

Turkish Journal of Electrical Engineering and Computer Sciences

Lithium-ion batteries are commonly preferred in electric vehicle applications. The relative capacity and state of health of a battery decrease with age. Therefore, accurate estimation of these parameters is essential. In this study a parametrical approach for estimation of battery state of health is proposed. A hybrid battery model that has a maximum error less than 3% is used. The relative capacity of the battery is estimated by using performance decrement with age. The method is validated by two different set of experiments. The first set is conducted with batteries that were aged by a controlled process and the second …


A Bidirectional Wireless Power Transfer System For An Electric Vehicle With A Relay Circuit, Chenyang Xia, Wei Wang, Yuling Liu, Kezhang Lin, Yanhe Wang, Xiaojie Wu Jan 2017

A Bidirectional Wireless Power Transfer System For An Electric Vehicle With A Relay Circuit, Chenyang Xia, Wei Wang, Yuling Liu, Kezhang Lin, Yanhe Wang, Xiaojie Wu

Turkish Journal of Electrical Engineering and Computer Sciences

In order to extend the transfer distance, enhance the tolerance for coil misalignment, and improve the capability of energy feedback and power transfer efficiency of conventional wireless power transfer (WPT) systems for electric vehicles, this paper presents a bidirectional WPT topology with a relay circuit. In the proposed topology, the primary and pickup circuits are implemented with virtually identical structures, which can operate in both magnetic field excitation and magnetic field receiving modes to facilitate bidirectional power flow between the primary side and the pickup side. A relay circuit is introduced to achieve high transfer efficiency under special conditions such …


A New Segmentation Method Of Cerebral Mri Images Based On The Fuzzy C-Means Algorithm, Mohamed Zaki Abderrezak, Mouatez Billah Chibane, Karim Mansour Jan 2017

A New Segmentation Method Of Cerebral Mri Images Based On The Fuzzy C-Means Algorithm, Mohamed Zaki Abderrezak, Mouatez Billah Chibane, Karim Mansour

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this work is to present a new method for cerebral MRI image segmentation based on modification of the fuzzy c-means (FCM) algorithm. We used local and nonlocal information distance in the initial function of the robust FCM model. The obtained results of the classification of MRI images showed the effectiveness of the suggested model. Calculation of the similarity index confirms that our method is well adapted to MRI images even in the presence of noise.


Heuristic Algorithm-Based Estimation Of Rotor Resistance Of An Induction Machine By Slot Parameters With Experimental Verification, Mehmet Çelebi̇, Murat Tören Jan 2017

Heuristic Algorithm-Based Estimation Of Rotor Resistance Of An Induction Machine By Slot Parameters With Experimental Verification, Mehmet Çelebi̇, Murat Tören

Turkish Journal of Electrical Engineering and Computer Sciences

The estimations of induction machine equivalent circuit parameters are still being widely used in the analysis and in determining the characteristics of the machine. Since the most important part of the machine is the rotor where torque is produced, the calculation of rotor resistance correctly will directly affect all other data. Almost all parameters belonging to the stator side can easily be determined through external measurements. However, due to the formulation of the rotor as a closed box, estimating rotor resistance and the rotor's slot shape by heuristic algorithms, without damaging the rotor physically, and comparing it with its actual …


Median Filtering Detection Based On Variations And Residuals In Image Forensics, Kang Hyeon Rhee Jan 2017

Median Filtering Detection Based On Variations And Residuals In Image Forensics, Kang Hyeon Rhee

Turkish Journal of Electrical Engineering and Computer Sciences

To attain a robust feature vector for median filtering detection (MFD) in digital forgery images, this paper presents a short feature vector that is made up of three types of feature sets. The first set is defined by the variation to be the 3-D length in the gradient difference of the intensity values of the adjacent row and column line pairs in the image, respectively. The second set is defined by the variation in the coefficient difference of the Fourier transform to be the 3-D length in the adjacent line pairs. The last set is defined by the residual image …


A Novel Optical Flow-Based Representation For Temporal Video Segmentation, Samet Akpinar, Ferdanur Alpaslan Jan 2017

A Novel Optical Flow-Based Representation For Temporal Video Segmentation, Samet Akpinar, Ferdanur Alpaslan

Turkish Journal of Electrical Engineering and Computer Sciences

Temporal video segmentation is a field of multimedia research enabling us to temporally split video data into semantically coherent scenes. In order to develop methods challenging temporal video segmentation, detecting scene boundaries is one of the more widely used approaches. As a result, representation of temporal information becomes important. We propose a new temporal video segment representation to formalize video scenes as a sequence of temporal motion change information. The idea here is that some sort of change in the optical flow character determines motion change and cuts between consecutive scenes. The problem is eventually reduced to an optical flow-based …


Ekf-Based Self-Regulation Of An Adaptive Nonlinear Pi Speed Controller For A Dc Motor, Omer Saleem, Urwa Omer Jan 2017

Ekf-Based Self-Regulation Of An Adaptive Nonlinear Pi Speed Controller For A Dc Motor, Omer Saleem, Urwa Omer

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a robust adaptive nonlinear proportional--integral (ANPI) scheme to control the speed of a direct-current (DC) motor. Unlike proportional--integral--derivative (PID) controllers, PI controllers have a simpler structure and they deliver effective control effort. However, due to inadequate controller gains, they are often unable to simultaneously improve the transient as well as the steady-state response of the system. A nonlinear PI (NPI) controller alleviates these issues and delivers a good response. In this research, the proportional and integral gains of the NPI controller are dynamically modulated via a nonlinear sigmoidal function (SiF) of the error dynamics of the motor's …


Time-Jerk Optimal Trajectory Planning Of A 7-Dof Redundant Robot, Shaotian Lu, Jingdong Zhao, Li Jiang, Hong Liu Jan 2017

Time-Jerk Optimal Trajectory Planning Of A 7-Dof Redundant Robot, Shaotian Lu, Jingdong Zhao, Li Jiang, Hong Liu

Turkish Journal of Electrical Engineering and Computer Sciences

In order to improve the efficiency and smoothness of a robot and reduce its vibration, an algorithm called the augmented Lagrange constrained particle swarm optimization (ALCPSO), which combines constrained particle swarm optimization with the augmented Lagrange multiplier method to realize time-jerk (defined as the derivative of the acceleration) optimal trajectory planning is proposed. Kinematic constraints such as joint velocities, accelerations, jerks, and traveling time are considered. The ALCPSO algorithm is used to avoid local optimization because a new particle swarm is newly produced at each initial time process. Additionally, the best value obtained from the former generation is saved and …


Indirect Adaptive Neurofuzzy Hermite Wavelet Based Control Of Pv In A Grid-Connected Hybrid Power System, Sidra Mumtaz, Laiq Khan Jan 2017

Indirect Adaptive Neurofuzzy Hermite Wavelet Based Control Of Pv In A Grid-Connected Hybrid Power System, Sidra Mumtaz, Laiq Khan

Turkish Journal of Electrical Engineering and Computer Sciences

Owing to the evolution of the smart grid, the emergence of hybrid power systems (HPSs), and the proliferation of plug-in-hybrid electric vehicles, the development of efficient and robust maximum power point tracking (MPPT) algorithms for renewable energy sources due to their inherent intermittent nature has overwhelmed the power industry. In this paper, an incremental conductance (IC) based Hermite wavelet incorporated neurofuzzy indirect adaptive MPPT control paradigm for a photovoltaic (PV) system in a grid-connected HPS is proposed. The performance of the proposed adaptive Hermite wavelet incorporated neurofuzzy MPPT control paradigm is validated through a comprehensive grid-connected HPS test-bed developed in …


Koch Fractal-Based Hexagonal Patch Antenna For Circular Polarization, Manisha Gupta, Vinita Mathur Jan 2017

Koch Fractal-Based Hexagonal Patch Antenna For Circular Polarization, Manisha Gupta, Vinita Mathur

Turkish Journal of Electrical Engineering and Computer Sciences

The design and performance of an inset feed modified hexagonal patch antenna for possible applications in ultrawideband communication systems is reported. The inset feed hexagonal patch antenna is modified by introducing a fractal up to the second iteration. A right-angled isosceles triangular microstrip antenna is used in the Koch fractal structure on the edges. The proposed antenna is a combination of two standard fractal structures, i.e. Sierpinski and Koch. A rectangular defect in the ground has also been done. The antenna is simulated by applying CST Microwave Studio simulation software. The results are verified by fabricating the antenna and tested …


Data Clustering Using Seed Disperser Ant Algorithm, Wen Liang Chang, Jeevan Kanesan, Anand Jayant Kulkarni, Harikrishnan Ramiah Jan 2017

Data Clustering Using Seed Disperser Ant Algorithm, Wen Liang Chang, Jeevan Kanesan, Anand Jayant Kulkarni, Harikrishnan Ramiah

Turkish Journal of Electrical Engineering and Computer Sciences

Nature-inspired optimization algorithms have become popular in the past decade. They have been applied to solve various kinds of problems. Among these would be data clustering, which has become popular in data mining in recent times due to the data explosion. In the last decade, many metaheuristic algorithms have been used to obtain improved data clustering optimization for solving data mining problems. In this paper, we applied the seed disperser ant algorithm (SDAA), which mimics the evolution of an Aphaenogaster senilis ant colony, and we introduced a modified SDAA that is a hybrid of K-means and SDAA for solving data …


Breast-Region Segmentation In Mri Using Chest Region Atlas And Svm, Aida Fooladivanda, Shahriar Baradaran Shokouhi, Nasrin Ahmadinejad Jan 2017

Breast-Region Segmentation In Mri Using Chest Region Atlas And Svm, Aida Fooladivanda, Shahriar Baradaran Shokouhi, Nasrin Ahmadinejad

Turkish Journal of Electrical Engineering and Computer Sciences

An important step for computerized analysis of breast magnetic resonance imaging (MRI) is segmentation of the breast region. Due to the similar signal intensity of fibroglandular tissue and the chest wall, the segmentation process is difficult for breasts with fibroglandular tissue connected to the chest wall. In order to overcome this challenge, a new framework is presented that relies on a chest region atlas. The proposed method first detects the approximated breast-chest wall boundary using an intensity-based operation. A support vector machine (SVM) then determines the connectivity of fibroglandular tissue to the chest wall by the extracted features from the …


An Online Approach For Feature Selection For Classification In Big Data, Nasrin Banu Nazar, Radha Senthilkumar Jan 2017

An Online Approach For Feature Selection For Classification In Big Data, Nasrin Banu Nazar, Radha Senthilkumar

Turkish Journal of Electrical Engineering and Computer Sciences

Feature selection (FS), also known as attribute selection, is a process of selection of a subset of relevant features used in model construction. This process or method improves the classification accuracy by removing irrelevant and noisy features. FS is implemented using either batch learning or online learning. Currently, the FS methods are executed in batch learning. Nevertheless, these techniques take longer execution time and require larger storage space to process the entire dataset. Due to the lack of scalability, the batch learning process cannot be used for large data. In the present study, a scalable efficient Online Feature Selection (OFS) …


A New Approach For Digital Image Watermarking To Predict Optimal Blocks Using Artificial Neural Networks, Raheleh Khorsand Movaghar, Hossein Khaleghi Bizaki Jan 2017

A New Approach For Digital Image Watermarking To Predict Optimal Blocks Using Artificial Neural Networks, Raheleh Khorsand Movaghar, Hossein Khaleghi Bizaki

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose a novel nonblind digital image watermarking based on discrete wavelet transform and singular value decomposition. This robust scheme takes advantage of artificial neural networks for selecting suitable image blocks in which the watermark signal can be embedded. Local characteristics of the blocks such as luminance and texture sensitivity are the main criteria that the selections are based on. Generally, selection is based on a prediction of the results with the objective of transparency and watermark resilience. In other words, before embedding the water mark signal, it is estimated which blocks would be the best for …


Comparative Study For Identification Of Multiple Alarms In Telecommunication Networks, Ati̇la Yilmaz Jan 2017

Comparative Study For Identification Of Multiple Alarms In Telecommunication Networks, Ati̇la Yilmaz

Turkish Journal of Electrical Engineering and Computer Sciences

Telecommunication networks consist of communication units interconnected physically or by means of protocols in order to provide basic services like data, voice, or image transfers. In this study, a modeling frame for network units and their links in a topological frame is presented based on a real mobile communication network named TASMUS (TAktik Saha MUharebe Sistemi - Tactical Field Combat System). Alarm handling is one of the most critical features required in communication networks. Based on simulated single alarm and multiple (double) alarm scenarios, known powerful alarm estimation approaches, namely the coding method, neural networks, and knowledge-based systems, have been …


Erp: An Efficient Reactive Routing Protocol For Dense Vehicular Ad Hoc Networks, Thandapany Sivakumar, Rajendiran Manoharan Jan 2017

Erp: An Efficient Reactive Routing Protocol For Dense Vehicular Ad Hoc Networks, Thandapany Sivakumar, Rajendiran Manoharan

Turkish Journal of Electrical Engineering and Computer Sciences

A vehicular ad hoc network (VANET) is a type of mobile ad hoc network (MANET) that provides an exchange of messages between vehicles. VANETs encourage researchers to create safety and comfort applications that will lead to intelligent transport systems. Conventional ad hoc routing methods may cause flooding of packets to find routes in a VANET. Hence, finding a route from the source to the destination vehicle by local broadcast techniques in densely populated urban areas may create a broadcast storm and network bandwidth is unnecessarily wasted to discover routes between source and destination vehicles. In this paper, an efficient routing …


Accelerating The Solving Of Nonlinear Equations Using The Homotopy Method: Application On Finding The Operating Point Of Complex Circuits, Fathi Dhiabi, Mohamed Boumehraz Jan 2017

Accelerating The Solving Of Nonlinear Equations Using The Homotopy Method: Application On Finding The Operating Point Of Complex Circuits, Fathi Dhiabi, Mohamed Boumehraz

Turkish Journal of Electrical Engineering and Computer Sciences

Analog circuits with nonlinear elements (e.g., diode, BJT, and CMOS) and integrated circuits are very complex systems. As a result, they are very difficult to analyze because of the need to generate a nonlinear equation system solution in order to do so. Solving nonlinear equations is still a challenging problem. Iterative methods, however, are frequently used to solve them. This paper describes a method that can be used to both accelerate the solving of nonlinear equations and find the operating point in various integrated circuits by construction of the global homotopy equation of the analog circuit. This is done by …


Case Study On Wavelet Choice Based On Statistical Image Quality Measures, Igor Vujovic, Ivica Kuzmanic Jan 2017

Case Study On Wavelet Choice Based On Statistical Image Quality Measures, Igor Vujovic, Ivica Kuzmanic

Turkish Journal of Electrical Engineering and Computer Sciences

Surveillance applications are under many negative influences, which should be suppressed, because these negative influences result in incorrectness of the motion mask. Suppression of several conflicting requirements can be optimized by a multiobjective approach. This paper proposes a multiobjective approach to selection of wavelets based on two main objectives: statistical image quality measures and execution time. Execution time is a measure of wavelets complexity. Segmentation is the final goal in order to insure precise operation of any surveillance algorithm. This paper presents a case study considering one, two, three, and four goals for wavelet selection comparison. Different wavelets are found …


Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü Jan 2017

Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü

Turkish Journal of Electrical Engineering and Computer Sciences

Temporal preconditioners to stabilize the marching-on-in-time (MOT)-based time domain integral equation (TDIE) solvers are proposed. Exponentially decaying functions are used as temporal preconditioners and the proposed scheme is applied to analyze scattering from perfect electrically conducting objects using the second-order formulation. The effectiveness of the proposed scheme is demonstrated via numerical examples. It is shown that the temporal preconditioners stabilize the MOT system and the solution. In addition, the initial condition problem of TDIEs is investigated by extending the second-order formulation of the time domain electric field integral equation to the time domain magnetic and combined field integral equations.


Discrete Design Optimization Of Distribution Transformers With Guaranteed Optimum Convergence Using The Cuckoo Search Algorithm, Levent Alhan, Nejat Yumuşak Jan 2017

Discrete Design Optimization Of Distribution Transformers With Guaranteed Optimum Convergence Using The Cuckoo Search Algorithm, Levent Alhan, Nejat Yumuşak

Turkish Journal of Electrical Engineering and Computer Sciences

Transformer design optimization methods presented in the literature rarely yield solutions directly applicable in production; the design engineer usually needs to convert the theoretical solution to a practical one. This problem is addressed in this paper, and a discrete transformer design optimization method is proposed that yields solutions with commercially available or productionally feasible dimensions, thus eliminating the need for further efforts of the design engineer to make the theoretical solution a feasible one. The cuckoo search, a nature-inspired metaheuristic algorithm, is used as the optimization algorithm in this study, and it is shown that the guaranteed global optimum solution …


Naive Forecasting Of Household Natural Gas Consumption With Sliding Window Approach, Mustafa Akpinar, Nejat Yumuşak Jan 2017

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, …


Dtreesim: A New Approach To Compute Decision Tree Similarity Using Re-Mining, Gözde Bakirli, Derya Bi̇rant Jan 2017

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 …