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2018

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Articles 13051 - 13080 of 13644

Full-Text Articles in Physical Sciences and Mathematics

Robust Restoration Of Distribution Systems Considering Dg Units And Direct Load Control Programs, Abolfazl Asadi, Mahmud Fotuhi Firuzabad Jan 2018

Robust Restoration Of Distribution Systems Considering Dg Units And Direct Load Control Programs, Abolfazl Asadi, Mahmud Fotuhi Firuzabad

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new method for restoration of distribution networks after a fault occurrence. This problem is solved from the viewpoint of the distribution system operator with the main goal of minimizing the operating cost during the fault clearance period. The effects of distributed generation (DG) units and direct load control (DLC) programs are considered in designing the proposed restoration procedure. Moreover, the uncertainties associated with the predicted loads of different nodes and the availability of DG are modeled here. Robust optimization is used to model the uncertainties of restoration problems and manage their associated risks. Finally, a robust …


Performance Evaluation Of Alumina Trihydrate And Silica-Filled Silicone Rubber Composites For Outdoor High-Voltage Insulations, Hidayatullah Khan, Muhammad Amin, Ayaz Ahmad Jan 2018

Performance Evaluation Of Alumina Trihydrate And Silica-Filled Silicone Rubber Composites For Outdoor High-Voltage Insulations, Hidayatullah Khan, Muhammad Amin, Ayaz Ahmad

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, silicone rubber-based composites have been widely investigated for outdoor applications due to their promising insulating properties. However, mechanical, thermal, and tracking properties of pure silicone rubber are very poor, which restrains its application for long-term performance. In this research work, the influence of microsized alumina trihydrate (ATH) and micro/nanosized silica (SiO$_{2})$ fillers on mechanical, thermal, and electrical properties of room temperature vulcanized silicone rubber (RTV-SiR) has been studied. SiR-blends with varying amounts of ATH and SiO$_{2}$ particles were prepared by blending in a two-roll mixing mill, compression molding, and postcuring processes in sequence. In order to evaluate …


Full Bridge Converter Based Independent Phase Control Of A Permanent Magnet Reluctance Generator For Wind Power Conversion Systems, Erkan Sunan, Fuat Küçük Jan 2018

Full Bridge Converter Based Independent Phase Control Of A Permanent Magnet Reluctance Generator For Wind Power Conversion Systems, Erkan Sunan, Fuat Küçük

Turkish Journal of Electrical Engineering and Computer Sciences

A Permanent Magnet Reluctance Generator (PMRG) possesses important features such as simplicity and low cost. Absence of rotor winding allows the generator to run in a wide speed range. The PMRG may have potential to be used in wind power conversion systems. An asymmetric half bridge (AHB) converter may be acceptable as a classical converter topology for PMRGs and offers independent phase control. The AHB converter with a torque ripple minimization-assisted maximum power point tracking algorithm not only provides significant torque ripple reduction on the mechanical side but also allows conversion of maximum wind energy to electrical energy. The major …


An Analysis Of Centennial Wind Power Targets Of Turkey, Egemen Sulukan Jan 2018

An Analysis Of Centennial Wind Power Targets Of Turkey, Egemen Sulukan

Turkish Journal of Electrical Engineering and Computer Sciences

Wind power has become one of the cost-effective options for improving the energy mix, while the wind farm installations reach higher shares by new capacity additions in Turkey, similar to many other countries, in order to support the sustainable development targets. Various methodologies are implemented and applied for planning and optimizing energy systems of countries, taking into consideration the energy, economy, and ecology aspects as a whole. The objective of this paper is to demonstrate the implications of "2023 energy targets" policy in terms of wind power. A futuristic scenario was tailored and applied to a comprehensive energy model for …


Estimation Of The Depth Of Anesthesia By Using A Multioutput Least-Square Support Vector Regression, Mercedeh Jahanseir, Kamal Setarehdan, Sirous Momenzadeh Jan 2018

Estimation Of The Depth Of Anesthesia By Using A Multioutput Least-Square Support Vector Regression, Mercedeh Jahanseir, Kamal Setarehdan, Sirous Momenzadeh

Turkish Journal of Electrical Engineering and Computer Sciences

Today, most surgeries are performed under general anesthesia where one of the most growing methods for anesthesia depth monitoring is using electroencephalogram (EEG). The bispectral index (BIS) is the most commonly used parameter for anesthesia depth monitoring using EEG, the validity of which is still to be studied before being accepted as a routine method by clinicians. This paper proposes a new technique for detecting the depth of anesthesia by means of EEG, which is based on multioutput least-squares support vector regression (MLS-SVR), which provides the probability that the patient is in the four different possible anesthesia states. In this …


Comparative Analysis Of Mabc With Knn, Som, And Aco Algorithms For Ecg Heartbeat Classification, Seli̇m Di̇lmaç, Zümray Ölmez, Tamer Ölmez Jan 2018

Comparative Analysis Of Mabc With Knn, Som, And Aco Algorithms For Ecg Heartbeat Classification, Seli̇m Di̇lmaç, Zümray Ölmez, Tamer Ölmez

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we proposed a classification method based on a nature-inspired algorithm, i.e., modified artificial bee colony (MABC). This method was applied to electrocardiogram (ECG) heartbeat classification. ECG data was obtained from MITBIH database. Eight different types of heartbeats (N, j, V, F, f, A, a, and R) were analyzed. For a better classification result, both time domain and frequency domain features were used. Feature selection was done by divergence analysis. MABC classification accuracy and heartbeat sensitivity values were compared with the results of other methods. Among other classifiers, k-nearest neighbor (KNN), Kohonen's self-organizing map (SOM), and ant colony …


An Algorithm For Image Restoration With Mixed Noise Using Total Variation Regularization, Cong Thang Pham, Guilhem Gamard, Andrei Kopylov, Thi Thu Thao Tran Jan 2018

An Algorithm For Image Restoration With Mixed Noise Using Total Variation Regularization, Cong Thang Pham, Guilhem Gamard, Andrei Kopylov, Thi Thu Thao Tran

Turkish Journal of Electrical Engineering and Computer Sciences

We present here an effective scheme for image denoising based on total variation regularization. The proposed scheme allows to efficiently remove Poisson noise as well as Gaussian noise simultaneously with the help of a new kind of data fidelity term, suitable for the mixed Poisson - Gaussian noise model. The results show that the algorithm corresponding to our new scheme outperforms the existing methods for mixed Poisson - Gaussian noise removal.


An Adaptive Machine Learning-Based Qoe Approach In Sdn Context For Video-Streaming Services, Asma Ben Letaifa Jan 2018

An Adaptive Machine Learning-Based Qoe Approach In Sdn Context For Video-Streaming Services, Asma Ben Letaifa

Turkish Journal of Electrical Engineering and Computer Sciences

In data service applications over the Internet, user perception and satisfaction can be assessed by quality of experience (QoE) metrics. QoE depends both on the users' perception and the used service, which together form end-to-end metrics. While network optimization has traditionally focused on optimizing network properties such as QoS, we focus in this work on optimizing end-to-end QoE metrics with the aim to deliver to the client a good QoE that can be monitored in real time. We argue that end-user QoE is a relevant measurement for network operators and service providers. In this paper, we present a machine learning …


Reconstruction Of Geometrical And Reflection Properties Of Surfaces By Using Structured Light Imaging Technique, Şükrü Ozan, Şevket Gümüşteki̇n Jan 2018

Reconstruction Of Geometrical And Reflection Properties Of Surfaces By Using Structured Light Imaging Technique, Şükrü Ozan, Şevket Gümüşteki̇n

Turkish Journal of Electrical Engineering and Computer Sciences

When a robust and dense surface reconstruction is aimed, structured light imaging techniques are usually much appreciated. In this paper we propose a method to reconstruct both geometrical and reflective properties of surfaces by using structured light imaging. We use a technique where a camera and a projector are both treated as viewing devices. They are calibrated in the same manner. Each visible point can be correctly located on both image planes without solving a correspondence problem; hence, a dense reconstruction can be obtained. Since both the camera and the projector are explicitly calibrated, lighting and viewing directions can be …


Feature Extraction Using Sequential Cumulative Bin And Overlap Mean Intensity Foriris Classification, Ahmad Nazri Ali, Shahrel Azmin Suandi, Mohd Zaid Abdullah Jan 2018

Feature Extraction Using Sequential Cumulative Bin And Overlap Mean Intensity Foriris Classification, Ahmad Nazri Ali, Shahrel Azmin Suandi, Mohd Zaid Abdullah

Turkish Journal of Electrical Engineering and Computer Sciences

This paper examines an approach generalizing a variant of the local binary pattern (LBP) method for iris feature extraction. The proposed method employs two different LBP variants called the sequential cumulative bin and overlap mean intensity for projecting the one-dimensional local iris textures into a binary bit pattern. The assigned bit, either 1 or 0 as a bit code, replaces the original intensity value using a specific condition for the respective reference element. The ratio value from the total transition of 1 to 0 along the row axis represents the feature of each iris image. The extraction only utilizes a …


Temporal Specificity-Based Text Classification For Information Retrieval, Shafiq Ur Rehman Khan, Muhammd Arshad Islam, Muhammad Aleem, Muhammad Azhar Iqbal Jan 2018

Temporal Specificity-Based Text Classification For Information Retrieval, Shafiq Ur Rehman Khan, Muhammd Arshad Islam, Muhammad Aleem, Muhammad Azhar Iqbal

Turkish Journal of Electrical Engineering and Computer Sciences

Time is an important aspect in temporal information retrieval (TIR), a subfield of information retrieval (IR). Web search engines like Google or Bing are common examples of IR systems. An important constituent of a search engine is news retrieval, where users present their information needs in the form of temporal queries. Users are usually interested in news documents focusing on a particular time period. Existing search engines rarely fulfill the temporal information requirements as they ignore the temporal information available in the content of news documents, also known as document focus time. Furthermore, information related to multiple time periods in …


Bvire Improved Algorithm For Indoor Localization Based On Rfid And A Linearregression Model, Noor Bahaaldin, Ergun Erçelebi̇ Jan 2018

Bvire Improved Algorithm For Indoor Localization Based On Rfid And A Linearregression Model, Noor Bahaaldin, Ergun Erçelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Traditional indoor location technologies such as infrared technology and ultrasonic technology are complex, expensive, or having unsatisfactory location accuracy. Radio frequency identification (RFID) technologies are very popular in many areas since their costs are very low. The tag in such technologies acts as the transmitter, and the radio signal strength indicator (RSSI) information is measured at the reader. However, RSSI information suffers strictly from the multipath circumstance and circumferential elements. Therefore, the localization accuracy of the boundary will be affected severely. In order to solve this problem, we introduce the boundary virtual reference label (BVIRE) algorithm to well utilize RFID …


A Selective Frequency Reconfigurable Bandstop Metamaterial Filter For Wlan Applications, Bachir Belkadi, Zoubir Mahdjoub, Mohammed Lamine Seddiki, Mourad Nedil Jan 2018

A Selective Frequency Reconfigurable Bandstop Metamaterial Filter For Wlan Applications, Bachir Belkadi, Zoubir Mahdjoub, Mohammed Lamine Seddiki, Mourad Nedil

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, two designs of bandstop filters are presented and implemented, each one composed of a coplanar waveguide loaded with a resonator. The first design has a structure with circular resonators, and the second design is a frequency reconfigurable filter with a rectangular spiral resonator and PIN diodes. The designs are based on the use of metamaterial to create notch filters for microwave applications. The Nicolson--Ross--Weir method, used to extract the refractive index, is also described to highlight the supernatural electromagnetic characteristic of metamaterials. From the simulation results, the filters exhibit high frequency selectivity via the presence of reflection …


Fiber-Optic Interferometric Sensor For Monitoring Automobile And Rail Traffic, Jan Nedoma, Marcel Fajkus, Radana Kahankova, Radek Martinek, Marek Dvorsky, Jan Vanus, Vladimir Vasinek, Daniel Cvejn Jan 2018

Fiber-Optic Interferometric Sensor For Monitoring Automobile And Rail Traffic, Jan Nedoma, Marcel Fajkus, Radana Kahankova, Radek Martinek, Marek Dvorsky, Jan Vanus, Vladimir Vasinek, Daniel Cvejn

Turkish Journal of Electrical Engineering and Computer Sciences

This article describes a fiber-optic interferometric sensor and measuring scheme including input-output components for traffic density monitoring. The proposed measuring system is based on the interference in optical fibers. The sensor, based on the Mach-Zehnder interferometer, is constructed to detect vibration and acoustic responses caused by vehicles moving around the sensor. The presented solution is based on the use of single-mode optical fibers (G.652.D and G.653) with wavelength of 1550 nm and laser source with output power of 1 mW. The benefit of this solution lies in electromagnetic interference immunity and simple implementation because the sensor does not need to …


A Matched E-H Plane T-Junction For X-Band Applications, Ashmi Chakraborty Das, Santanu Dwari, Amit Bage Jan 2018

A Matched E-H Plane T-Junction For X-Band Applications, Ashmi Chakraborty Das, Santanu Dwari, Amit Bage

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a method of moment-based analysis of an E-H plane T-junction to find its scattering parameters. The results show that the network is not matched at its ports. Therefore, matching networks have been included in the structure to establish matching at the ports. The matching structure includes an inductive window at the H-plane arm and a bisected funnel structure at the junction. Results of the modified structure show simultaneous matching at all the four ports at 9 GHz, which makes it suitable for X-band application.


Emi Filter Design Based On The Separated Electromagnetic Interference In Switched Mode Power Supplies, Samet Yalçin, Şükrü Özen, Selçuk Helhel Jan 2018

Emi Filter Design Based On The Separated Electromagnetic Interference In Switched Mode Power Supplies, Samet Yalçin, Şükrü Özen, Selçuk Helhel

Turkish Journal of Electrical Engineering and Computer Sciences

Usage of switch mode power supplies (SMPS) has been increased tremendously in recent years due to their advantages compared to conventional ones. In spite of their advantages, SMPSs cause conducted and radiated emissions due to the fact that they switch on and off at specific frequencies. Electromagnetic interference (EMI) filters are mostly preferred equipment for the reduction of conducted emission for coupled circuits. Improved EMI filter in the literature to suppress both common and differential mode noises sourced by ATX (a sample of SMPS) power supply has been proposed. A proposed filter was designed by use of AWR Microwave Office …


Classification And Regression Analysis Using Support Vector Machine For Classifying And Locating Faults In A Distribution System, Sophi Shilpa Gururajapathy, Hazlie Mokhlis, Hazlee Azil Bin Illias Jan 2018

Classification And Regression Analysis Using Support Vector Machine For Classifying And Locating Faults In A Distribution System, Sophi Shilpa Gururajapathy, Hazlie Mokhlis, Hazlee Azil Bin Illias

Turkish Journal of Electrical Engineering and Computer Sciences

Various fault location methods have been developed in the past to identify the faulty phase, fault type, faulty section, and distance. However, this identification is commonly conducted in a separate manner. An effective fault location should be able to identify all of these at the same time. Therefore, in this work, a method using a support vector machine (SVM) to identify the fault type, faulty section, and distance considering the faulty phase is proposed. The proposed method uses voltage sag magnitude of the distribution system as the main feature for the SVM to identify faults. The fault type is classified …


The Impact Of Transmission Power Levels Set Size On Lifetime Of Wireless Sensor Networks In Smart Grids, Hüseyi̇n Uğur Yildiz Jan 2018

The Impact Of Transmission Power Levels Set Size On Lifetime Of Wireless Sensor Networks In Smart Grids, Hüseyi̇n Uğur Yildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless sensor networks (WSNs) have been confirmed as one of the most promising technologies for many smart grid (SG) applications due to their low complexity and inexpensive costs. A typical WSN is formed with numerous battery limited sensor nodes mounted on critical components of a SG system for monitoring applications. Acquired monitoring data by sensor nodes are conveyed to the base station generally by using multihop communication techniques. WSN-based SG applications encounter severe propagation losses due to extreme channel conditions of the SG environment. In order to reduce possible packet errors caused by channel variations, transmission power control approaches can …


Application Of Acf-Wavelet Feature Extraction For Classification Of Some Artificial Pd Models Of Power Transformer, Vahid Parvin Darabad Jan 2018

Application Of Acf-Wavelet Feature Extraction For Classification Of Some Artificial Pd Models Of Power Transformer, Vahid Parvin Darabad

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, 7 different artificial partial discharge (PD) models of power transformer defect types are built in a high voltage laboratory, and then PD signals are recorded in the whole power frequency cycle to develop a preliminary PD knowledge base. A specific technique is used to extract single PD events from the recorded knowledge base. By application of wavelet transform, different decomposition levels of extracted PD signals are investigated. Feature extraction is performed by application of statistic moments on the autocorrelation function of PD signal decompositions. "Best" features are selected based on the F-test. To evaluate the performance of …


A Frequency-Tuned Magnetic Resonance-Based Wireless Power Transfer System With Near-Constant Efficiency Up To 24 Cm Distance, Seyi̇t Ahmet Si̇s, Selçuk Kavut Jan 2018

A Frequency-Tuned Magnetic Resonance-Based Wireless Power Transfer System With Near-Constant Efficiency Up To 24 Cm Distance, Seyi̇t Ahmet Si̇s, Selçuk Kavut

Turkish Journal of Electrical Engineering and Computer Sciences

In magnetic resonance-based wireless power transfer systems, the main challenge arises from varying distances between coils during power transfer because distance variations ultimately reduce the power transfer efficiency. Frequency-tuned wireless power transfer systems provide an almost-constant output power to the load up to a critical coupling distance. However, the critical coupling distance and power transfer efficiency are dependent on coil size, source, and load resistances. The purpose of this paper is to discuss this dependency with an equivalent circuit model, determine a suitable coil size for given design specifications, and set up a frequency-tuned system that is based on tracking …


Controlling The Speed And Flux Of A Dual Stator Winding Induction Motor Using An Emotional Intelligent Controller And Integration Algorithm, Hojat Moayedirad, Mohammad Ali Shamsi Nejad Jan 2018

Controlling The Speed And Flux Of A Dual Stator Winding Induction Motor Using An Emotional Intelligent Controller And Integration Algorithm, Hojat Moayedirad, Mohammad Ali Shamsi Nejad

Turkish Journal of Electrical Engineering and Computer Sciences

The appropriate efficiency of a dual stator winding squirrel-cage induction motor (DSWIM) is obtained when the ratio of two frequencies feeding the machine is equal to the ratio of the number of poles. In the vector control method, the estimation of flux at low speed is difficult. To solve this problem, researchers have benefited from the free capacity of the two windings of the stator. This makes the motor deviate from its standard operating mode at low speed. The main purpose of the present study is to reduce the power losses of the inverter units in the sensorless DSWIM drive …


Attenuating Saturated-Regulator Operation Effect Of Brushless Dc Motors Through Genetic-Based Fuzzy Logic Estimator, Emre Çeli̇k, Ni̇hat Öztürk Jan 2018

Attenuating Saturated-Regulator Operation Effect Of Brushless Dc Motors Through Genetic-Based Fuzzy Logic Estimator, Emre Çeli̇k, Ni̇hat Öztürk

Turkish Journal of Electrical Engineering and Computer Sciences

As brushless DC motor (BLDCM) speed approaches base speed, current regulators gradually saturate and lose their ability to perform their regulating task, which causes a dramatic fall in the phase currents and motor power. To control the current to a greater extent and avoid power decline, a new reference current generation technique based on a simple fuzzy logic estimator (FLE) is introduced in this paper. According to motor speed and current command, the developed FLE decides the proper commutation angle $\alpha $, which is the angle relative to normal commutation instant used for setting the current slew rate during commutation. …


Adaptive Antisingularity Terminal Sliding Mode Control For A Robotic Arm With Model Uncertainties And External Disturbances, Kiem Nguyen, Tinh Nguyen, Quyen Bui, Minhtuan Pham Jan 2018

Adaptive Antisingularity Terminal Sliding Mode Control For A Robotic Arm With Model Uncertainties And External Disturbances, Kiem Nguyen, Tinh Nguyen, Quyen Bui, Minhtuan Pham

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a radical adaptive terminal sliding mode control method for a robotic arm with model uncertainties and external disturbances is proposed in such a way that the singularity problem is completely dealt with. A radial basis function neural network (RBFNN) with an online weight tuning algorithm is employed to approximate unknown smooth nonlinear dynamic functions caused by the fact that there is no prior knowledge of the robotic dynamic model. Furthermore, a robust control law is utilized in order to eliminate total uncertainty composed of model uncertainties, external disturbances, and the inevitable approximation errors resulting from the finite …


New Optimization Algorithm Inspired By Fluid Mechanics For Combined Economic And Emission Dispatch Problem, Ruyi Dong, Shengsheng Wang Jan 2018

New Optimization Algorithm Inspired By Fluid Mechanics For Combined Economic And Emission Dispatch Problem, Ruyi Dong, Shengsheng Wang

Turkish Journal of Electrical Engineering and Computer Sciences

With the increasing concern over environmental protection, the combined economic emission dispatch (CEED) problem has received much attention. It needs to minimize both fuel cost and emission pollution. This study aims to propose a new metaheuristic algorithm inspired by fluid mechanics to solve the CEED problem with the weighted sum method. The new algorithm simulates the inverse process of fluid flowing spontaneously from high pressure to low pressure, similar to the optimization process of the CEED problem. When applied in two real-world cases, the new algorithm achieves better performance compared with other algorithms in the literature.


Estimating The Selectivity Of Like Queries Using Pattern-Based Histograms, Mehmet Ayti̇mur, Ali̇ Çakmak Jan 2018

Estimating The Selectivity Of Like Queries Using Pattern-Based Histograms, Mehmet Ayti̇mur, Ali̇ Çakmak

Turkish Journal of Electrical Engineering and Computer Sciences

Accurate cost and time estimation of a query is one of the major success indicators for database management systems. SQL allows the expression of flexible queries on text-formatted data. The LIKE operator is used to search for a specified pattern (e.g., LIKE "luck %") in a string database. It is vital to estimate the selectivity of such flexible predicates for the query optimizer to choose an efficient execution plan. In this paper, we study the problem of estimating the selectivity of a LIKE query predicate over a bag of strings. We propose a new type of pattern-based histogram structure to …


A Distributed Admm Approach For Energy-Efficient Resource Allocation In Mobile Edge Computing, Weiwei Fang, Wenchen Zhou, Yangyang Li, Xuening Yao, Feng Xue, Naixue Xiong Jan 2018

A Distributed Admm Approach For Energy-Efficient Resource Allocation In Mobile Edge Computing, Weiwei Fang, Wenchen Zhou, Yangyang Li, Xuening Yao, Feng Xue, Naixue Xiong

Turkish Journal of Electrical Engineering and Computer Sciences

Mobile edge computing (MEC) is a new promising technique to provide cloud-computing capabilities at the edge of cellular networks in close proximity to mobile users. In this paper, we consider joint optimization of the communication and computation resources in a multiuser, multiserver MEC system. The objective of this optimization problem is to minimize the total energy consumption of mobile devices under the time-sharing constraint. Given the fact that no coordination is involved between mobile devices, we propose a light-weight and decentralized algorithm based on the alternating direction method of multipliers (ADMM) framework. Experimental results demonstrate that the proposed algorithm performs …


Artificial Immune System Based Wastewater Parameter Estimation, Cengi̇z Sertkaya, Ni̇lüfer Yurtay Jan 2018

Artificial Immune System Based Wastewater Parameter Estimation, Cengi̇z Sertkaya, Ni̇lüfer Yurtay

Turkish Journal of Electrical Engineering and Computer Sciences

The basis of a wastewater treatment system is to achieve the desired characteristics of the wastewater treatment process. An estimation of the obtained wastewater treatment characteristics provides the information needed to set up the current process steps, and it is important to have an optimum treatment. In this study, an artificial immune system (AIS) structure is developed to estimate important wastewater output parameters such as pH, DBO, DQO, and SS for the first time. The proposed AIS models are based on the clonal selection principle, and the dataset is provided from the University of California Irvine (UCI) Machine Learning Library. …


Rapid Translation Of Finite-Element Theory Into Computer Implementation Based On A Descriptive Object-Oriented Programming Approach, Murat Yilmaz Jan 2018

Rapid Translation Of Finite-Element Theory Into Computer Implementation Based On A Descriptive Object-Oriented Programming Approach, Murat Yilmaz

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, we present a framework for rapid prototyping of finite element (FE) theory for computer implementations. For this purpose, we propose an object-oriented (OO) application programming interface in the form of a domain-specific modeling language (DSML). In contrast to the traditional OO approach, the proposed framework deliberately avoids the use of subclassing for concrete implementations of node and element classes; it uses external objects, namely descriptors, instead. The descriptive design of the DSML provides developers with generic programming support for the construction and solution of discretization schemes, in the context of partial differential equations, in a self-explanatory syntax. …


Influence Maximization In Social Networks: An Integer Programming Approach, Muhammed Emre Keski̇n, Mehmet Güray Güler Jan 2018

Influence Maximization In Social Networks: An Integer Programming Approach, Muhammed Emre Keski̇n, Mehmet Güray Güler

Turkish Journal of Electrical Engineering and Computer Sciences

The use of social networks has been spreading rapidly in recent years. There is a growing interest in influence maximization in social networks, especially after observing that the effects of social events of the Arab Spring, Gezi events of Turkey, uprising in Ukraine, etc. have been built by the help of social networks. Consequently, many institutions like political parties or commercial firms are willing to spread their messages throughout social networks. There are many studies that concentrate on finding the most influential initial nodes, called seeds, which maximize the spread of an intended message over the social network. However, most …


Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby Jan 2018

Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby

OES Faculty Publications

Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO2 …