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In this paper a cable-stayed bridge and a suspension bridge with closer main span lengths are considered to determine the effects of near-fault and far-fault ground motions on the structural responses of these bridges under asynchronous excitations. While the Tatara Cable-Stayed Bridge constructed in Japan is preferred as a cable-stayed bridge model, the Fatih Sultan Mehmet Bridge constructed in Turkey is considered as a suspension bridge model. While the geometric nonlinearity including P-delta effects resulting from the self weight of the suspension bridge is considered in the dynamic analysis of the suspension bridge, the nonlinearity of the cable-stayed bridge cables are taken into account with the equivalent modulus of elasticity. The results show that the traveling wave has a complicated effect on the structural responses like displacements and internal forces, and underestimates or overestimates the structural responses depending on the wave propagation velocity and the considered structural responses. It is also observed that the increment of the responses for the infinitely propagating near fault ground motions with respect to the farfault ground motions are obviously larger than the incerement obtained for the 250 m/s wave propagation velocity. [ABSTRACT FROM AUTHOR]

The BIST 100 index is used to evaluate the success of the highest 100 shares in terms of criteria such as free float rate, transaction volume and market value. In this paper, it is aimed to determine whether the BIST 100 returns have a chaotic structure and short term predictability. First of all, using BIST 100 price index data between 02.01.2008 and 02.01.2018, BIST 100 returns were obtained. Using the optimal delay time and embedding dimension, the phase space required for chaos analysis was reconstructed. Then, the correlation dimension of the chaotic attractor in the new phase space obtained for this return series was calculated. BDS (Brock, Dechert and Scheinkman) test was used to determine whether the BIST 100 structure was linear. However, the Hurst exponential coefficient was determined by the transformed width method to determine whether the series had long term memory. As a result of positive Lyapunov exponent of return series, it was determined whether this series showed chaotic behavior. Following the chaos analysis, BIST 100 index was estimated by ANN and ANFIS model. The outputs of the model with the lowest error value are transformed into return series, and the estimated values of the BIST 100 returns are obtained. [ABSTRACT FROM AUTHOR]

The paper demonstrates the determination of the fracture parameters of concretes included recycled aggregate (RA) and silica fume (SF) and the crack pattern of a reinforced concrete beam. The parameters of fracture for conventional concrete (NAC) and recycled aggregate concrete (RAC) are calculated and a comparative study is con ducted. Double-K fracture model (DKFM) is considered in this paper and the required parameters for DKFM are obtained from fictitious crack model simulated using finite element method (FEM) in Abaqus (i.e., crack mouth openning (CMOD)). In the simulation parts geometric nonlinearity and material nonlinearity is considered and the parameters of materials for modelling applications depends on the experiments. The fracture parameters are calculated after obtaining the FEM model analysises. The implemented study of fracture behaviour of the conventional and recycled aggregate concretes with and without SF and RA reveals that the conventional concrete fracture models (double-K fracture model) could be used to determine the fracture parameters and fracture behaviour of RAC and both SF and RA use in concrete has an effect on fracture properties is found. Moreover, crack pattern of a reinforced concrete beam with and without RA and SF is investigated. According to the results, number of cracks decrease but the depth of cracks increase and initial cracking thoughness increases if both RA and SF are usedat various ratios in the concretes. Although RA inclusion in concretes decreases the rigidity of the beam, approximately equal elastic bearing capacity of the beam is found. [ABSTRACT FROM AUTHOR]

Nowadays, the usage areas and the roles of robots increase rapidly in daily life. Liquid transfer with robots is one of the topics which has recently been studied by researchers. In this paper, the transport of a liquidfilled container without slosh by a planar dual-arm cooperative robot was investigated. When a dual-arm robot carries an object, a closed kinematic chain is formed and a set of constraints that increase the mathematical complexity of the system appear during the motion. In this study, the nonlinear dynamics of the liquid slosh was linearized by Extended Taylor Series functions. Then, Pole Placement and Linear Quadratic Regulator (LQR) control techniques were used to achieve high-speed transport of the liquid-filled container without slosh and pouring, and the results of two techniques were compared with each other. [ABSTRACT FROM AUTHOR]

Automatic image captioning is a challenging issue in artificial intelligence, which covers both the fields of computer vision and natural language processing. Inspired by the later advances in machine translation, a successful encoder-decoder technique is currently the state-of-the-art in English language captioning. In this study, we proposed an image captioning model for Turkish Language. This paper evaluates the encoderdecoder model on MS COCO database by coupling an encoder Convolutional Neural Network (CNN) -the component that is responsible for extracting the features of the given images-, with a decoder Recurrent Neural Network (RNN) -the component that is responsible for generating captions using the given inputs- to generate Turkish captions. We conducted the experiments using the most common evaluation metrics such as BLEU, METEOR, ROUGE and CIDEr. Results show that the performance of the proposed model is satisfactory in both qualitative and quantitative evaluations. Finally, this study introduces a Web platform (http://mscoco-contributor.herokuapp.com/website/), which is proposed to improve the dataset via crowdsourcing and free to use. The Turkish MS COCO dataset is available for research purpose. When all the images are completed, a Turkish dataset will be available for comparative studies. [ABSTRACT FROM AUTHOR]

The main purpose of the supply chain system is to make profit and meet customers' expectations simultaneously. Therefore supplier evaluation and selection is a significant strategic decision for reducing operating costs and improving organizational competitiveness to develop business opportunities. Moreover, with increasing concern towards environmental protection and sustainable development, it becomes important to pay more attention to environmental requirements and evaluating the potential suppliers by incorporating green factors into the selection process. Therefore Selected suppliers should take the "voice" of customers into account by providing the company's requests. In this context, the aim of this paper is to put forward an integrated approach for green supplier selection by considering various environmental performance requirements and criteria. The proposed approach addresses the inter-relationships between the customer requirements (CRs) with the aid of decision-making trial and evaluation laboratory (DEMATEL) method while constructing a relationship structure. Quality function deployment (QFD) model is used to establish a central relationship matrix in order to identify degree of relationship between each pair of supplier selection criteria and CRs. Afterwards, interval type-2 fuzzy analytic hierarchy process (IT2 FAHP) applied to prioritize and rank the alternative suppliers. At the ende a case study is presented to reveal the potentiality and aptness of the proposed methodology. [ABSTRACT FROM AUTHOR]

Most studies on permanent magnet synchronous motors (PMSMs) focus on either interior type or surface mounted magnet configurations and their design changes. This paper deals with the improvements on PMSMs' efficiency and performance after Halbach Array implementation by using meta-heuristic optimization algorithms. Analytical and numerical modeling of the motor are achieved and finite element method (FEM) is used for the numerical models. Particle swarm optimization & genetic algorithm were performed for the optimal design of the geometrical parameters of the permanent magnet (PM). The analytical and numerical results of the proposed design are compared to the analytical and/or numerical results of the reference motor. The improvements in efficiency, power/weight ratio, and cost are achieved with the optimized motor structure for the same motor requirements. [ABSTRACT FROM AUTHOR]

The IEEE 802.11 standard defines the specifications of the media access control (MAC) and physical (PHY) layers for vehicular ad hoc networks (VANETs). In IEEE 802.11, distributed coordination function (DCF) is the fundamental access technique, which employs a carrier sense multiple access with collision avoidance (CSMA/CA) mechanism to access the medium. In addition, request to send (RTS)/ clear to send (CTS) mechanism is used to overcome hidden vehicular nodes problem. In this paper, an analytical model is developed to evaluate the performance of the IEEE 802.11 MAC for VANETs. The algorithm of CSMA/CA and RTS/CTS mechanism are presented. Markov chain model based analytical analysis is presented to investigate the performance. Parameters that can influence the performance such as vehicles velocity, vehicle density, contention window size, maximum retransmission limit etc. are considered. The relationship between the performance metrics and parameters are derived. Throughput, packet dropping rate (PDR) and delay expressions are obtained. Moreover, numerical results are demonstrated to verify the analysis. The comparison between CSMA/CA and RTS/CTS access mechanisms is presented. [ABSTRACT FROM AUTHOR]

In this paper, a novel clutter removal method based on non-local means (NLM) filtering for groundpenetrating radar (GPR) is presented. NLM filter which can be considered as a generalization of bilateral filter diverges from other local averaging filters since it determines the pixel weights by investigating the self-similarities in the image. NLM filter is extended to a multiscale-multidirectional version called multiscale directional non-local means (MDNLM) filter. Then, it is used to decompose the GPR image into approximation and detail subbands to capture the intrinsic geometrical structures of GPR image that contain both target and clutter information. After directional decomposition, the clutter is eliminated by keeping the diagonal information as target component. Finally, the inverse transform of the remaining subbands provides the reconstructed clutter-free GPR image. Results for both simulated and real datasets are presented to validate the superiority of the proposed method over widely used clutter reduction methods, as well as the recently proposed neighborhood filter based one, in terms of receiving operator characteristic (ROC) curves, thus improving detection performance. [ABSTRACT FROM AUTHOR]

Buildings - especially the residential buildings - are among the high priority areas in climate change due to their large share of CO2 emissions, their significant energy saving potentials and the increased comfort expectations of their occupants. A systematic and numerical investigation of how building performance will be affected by climate change in the future is crucial for both retrofitting the existing buildings and making long-term strategical decisions. This paper presents the simulation-based results of the climate change impact assessment for a typical multi-storey residential building in Istanbul. In this study, RCP4.5 and RCP8.5 scenarios - representing the low/medium and high CO2 emission scenarios - defined by the Intergovernmental Panel on Climate Change (IPCC) are used to generate two different climate data sets for 2060. Three cooling scenarios (natural ventilation, hybrid ventilation and air-conditioned) have been developed to represent different building usage profiles for the building simulations. Investigated performance metrics were selected as building heating/cooling energy consumption, CO2 emission and occupant thermal comfort. Analysis results analysis show that the predicted temperature rise will have a strong impact on the building cooling energy consumption and/or occupant thermal comfort. The results indicate the necessity of taking measures for adaptation of buildings to the changing climate and the importance of decarbonization of electricity generation to mitigate the effects of climate change. This study will also serve as a basis for future retrofit studies for the changing climate. [ABSTRACT FROM AUTHOR]

Nowadays, there has been an increasing attention to enterprise resource planning (ERP) software implementation projects due to the rapid improvements in information technologies. In this context, project managers may face with several uncertainties during the project planning and scheduling phases. In this paper, scheduling of a multi-objective ERP implementation project is targeted under human resource constraints and uncertainty. Through the proposed interval programming based solution approach, uncertainties of the project parameters/inputs as well as the project schedules/outputs which represent the starting or completion times of the activities can be easily handled. Therefore, several alternative project schedules can be generated by making use of the proposed approach according to the risk appetite of the project managers. Additionally, efficiency and reliability factors of the human resources are also taken into account. Finally, computational results of a real-life application have shown that more applicable and reliable compromise solutions can be generated by the proposed approach considering both project makespan and effective utilization of the human resource capacities. [ABSTRACT FROM AUTHOR]

The ankle musculoskeletal system continuously changes the joint stiffness during walking. Inspired by this biomechanical behavior, a variable stiffness ankle exoskeleton robot called as VS-AnkleExo was introduced. Although a variable stiffness ankle joint design provides a flexible, safe and biomimetic, the difficulty of stable and precise position tracking under external disturbances is the biggest problem of such soft actuators. In this paper, the position control performance and sensitivity to external disturbances of hybrid controllers created by combining different types of fuzzy logic theory and classical Proportional Integral Derivative (PID) control method implemented on VS-AnkleExo were evaluated experimentally. VS-AnkleExo will be used for applications such as rehabilitation and walking assistance. In this study, firstly, PID, Fuzzy PD, Fuzzy PD+I, Fuzzy PD+PID and ZTS (Z, T and S type membership functions) Fuzzy PD controllers position tracking performances were evaluated for different references without disturbances. In the continuation of the study, the experiments of step and sine inputs response with disturbances were carried out to test the sensitivity of the proposed controllers against the disturbing forces. The test results showed that the Fuzzy PD+PID controller could reduce position tracking errors more effectively than other controllers and was more robust against externally applied disturbances. [ABSTRACT FROM AUTHOR]

It is known that a structure is expected to behave nonlinearly when subject to strong ground motions. For evaluating the nonlinear seismic response of the structural system, one of the most reliable ways is to use energy based approach. Energy based design can be expressed as the balance of energy input and the energy dissipation capacity of the structure. Energy based studies have been usually done for single degree of freedom systems. Studies are needed for real structures in multi degree of freedom systems (MDOFs) in framework of the energy based design methodology. The aim of this paper is to determine seismic energy demands in steel special moment frames that have various height levels and span lengths for the evaluation of energy-based approach in the framework of performance-based design. Low, medium and high-rise steel special moment frames are examined using linear and nonlinear dynamic time history analyses. The results are evaluated to obtain inelastic hysteretic energy distribution and energy demand spectrum.It is shown that total input energy and total hysteretic energy is not a constant value and depends on the properties of the structure and ground motion properties. [ABSTRACT FROM AUTHOR]

Generative adversarial training has been one of the most active research topics and many researchers have conducted their studies on Generative Adversarial Network (GAN) shortly after it is claimed to be one of the most promising research area of the last decade by pioneers of the deep learning community. On the other hand, the idea behind generators has also reemerged autoencoder models such as Variational Autoencoder (VAE). Therefore, autoencoder models have gained their popularity back. Some restrictions of GAN models such as lack of inference mechanism, GAN and VAE based hybrid models have proposed addressing image generation. With the effect of these notions and studies, we have also considered VAE and GAN hybrid models. For obtaining synthetic but at the same time high-resolution handwritten-looking images without any training, Compositional Pattern Producing Network (CPPN) is adapted from previous studies for combining with VAE and adversarial training. For improving generation capabilities, an objective from a previous VAE/GAN model is also adapted for our VAE/CPGAN hybrid model. For analyzing the proposed model performance, baseline models such as GAN, VAE and VAE/GAN are also evaluated for comparisons. In this paper. it is clearly seen the proposed model is capable of the generating realistic and scalable super resolution synthetic images on a common dataset. [ABSTRACT FROM AUTHOR]

City distribution companies or companies with high consumption are required to report monthly consumption demand forecasts for the year ahead and year based daily consumption demand forecasts in natural gas sector. This paper studies forecasting daily and monthly demand for mid-term natural gas as contract estimations using statistical methods (time series decomposition, Holt-Winters exponential smoothing, ARIMA/SARIMA), include univariate seasonality. In the study, 365-day forecast is performed on a daily basis and 12-month forecast is performed on a monthly basis at once. Among all statistically appropriate forecasting models, ARIMA(1,0,1)1(0,1,1)365 model found daily basis year ahead natural gas consumptions the best with the lowest error, highest compliance with 24.6% MAPE and 0.802 R², for the year 2014. The coefficients of this model were statistically significant and the residuals were found as white noise. The same model has the lowest error (MAPE - 11.32%) and highest compliance (R² - 0.981) in the monthly estimations as well. The results show that seasonal ARIMA models are the most appropriate estimation technique among the univariate techniques. The fact that many predictions can be made at a time and the results are acceptable allow these techniques to be used in the year ahead monthly and daily forecasting. [ABSTRACT FROM AUTHOR]

In this paper the problem of microwave imaging of an impedance cylinder is investigated with Newton's method. To this aim, the scattered field from a circular cylinder with homogeneous impedance is derived for plane wave illumination. In this step, the scattering configuration is assumed as a TMz scenario, where the impedance cylinder is infinite in z axis and the electric fields are parallel to the same axis. Then, in the inverse scattering phase the impedance and the radius of the target have to be estimated. To this purpose, an initial value is assigned to both variables and the scattered field corresponding to these initial values is evaluated. The difference between the scattered fields is divided to a matrix, which contains the derivative of the scattered field with respect to unknown variables, to estimate the update amount for each parameter. Then, both parameters are updated and this process continues up until to the difference between the measured and the calculated fields goes below to a predefined threshold. Thus, an estimate of the impedance and the radius of the cylinder is obtained. Results show that the proposed method can reconstruct the unknown parameters with limited aperture - multiple frequency measurements. [ABSTRACT FROM AUTHOR]

In this paper, a new hyperspectral image classification method based on 2-dimensional complex Gabor filtering and deep convolutional neural networks is proposed. Specifically, as a deep learning model, convolutional neural network is aimed to extract distinctive high-level features. Deep-learned and Gabor feature extraction methodologies are simultaneously performed on the input hyperspectral samples. Gabor features are calculated by implementing complex Gabor filtering only on the first three principal components of the hyperspectral image. The proposed hybrid model uses Gabor transform to obtain local image features, such as edges, corners and texture. The Gabor features of the images are calculated at multiple orientations and frequencies. Then, deep features and Gabor features are fused to obtain a more robust and discriminative feature vector. Hybrid feature vector is used as input to a softmax classifier for hyperspectral image classification. The parameters of the proposed deep learning architecture are optimized using a small training set. Thus, the over-fitting problem of the proposed convolutional neural network has been reduced to some extent. Experiments performed on two popular hyperspectral datasets show that the proposed method can achieve better classification performance than some conventional methods. Classification results demonstrates that the proposed hybrid model is an efficient method for feature extraction and classification of hyperspectral images. [ABSTRACT FROM AUTHOR]

In this paper, design of a new single layer ultra-wide band (UWB), band-stop frequency selective surface (FSS) with polarization independent and angular stability is presented. The designed FSS consists of a circleshaped conductive strip and a ring-shaped cross-dipole conductive strip. The unit cell size that forms the UWB-FSY is 0.07λ × 0.07λ, where λ is free-space wavelength corresponding to the lowest frequency of the UWB band. The -3 dB bandwidth of proposed FSS is between 3.5 GHz and 11 GHz (at normal incidence) frequencies, which covers the entire UWB band that is defined by The U.S. Federal Communications Commission (FCC). Due to compact size of unit cell, the presented UWB-FSS has good angular stability up to 60° incident angles both perpendicular (TE) and parallel (TM) polarization. The designed UWB-FSS was simulated. Afterall, simulation results was confirmed with the measurements. [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) is a major candidate technology for the future radio networks due to its potential to have high spectral efficiency and to support massive connections. It is also an important advantage for the NOMA to be very compatible with the other physical layer techniques. The relay-aided-NOMA which consists of the interplay between cooperative communication and NOMA, offers very large coverage area besides the high spectral efficiency and the massive connectivity. Hence, the relay-aided-NOMA has great recent attention. Most of these studies are devoted to reveal outage probability and the overall system capacity performances of the systems. However, the bit error performances have been ignored. In this paper, theoretical end-to-end (E2E) average bit error probability (ABEP) expressions are derived for the relay-aided-NOMA using a relay with the decode-forward (DF) protocol. The derived expressions are validated through Monte Carlo simulations. The E2E error performance of the system are examined for different system parameters. Moreover, by considering user fairness in terms of error performance, it is discussed how the optimum power allocation should be done. And finally, a sub-optimum power allocation algorithm is presented according to the proportional fairness index. [ABSTRACT FROM AUTHOR]

In large-scale part manufacturing industries such as nuclear, aerospace and power generation, robotic milling is potentially a promising portable manufacturing technology to decrease the overall costs. The lack of enclosures around the robotic milling units blocks the use of flood coolant contrary to CNC machining centres. In such cases, the minimal quantity lubrication (MQL) technique is suitable, which on the other hand, agrees with the green manufacturing theme of the industry in the 21st century. However, the effect of MQL parameters such as the air pressure, oil flow rate, oil type, and pulse rate on tool life and surface integrity in end milling have not been well studied and understood yet. In this paper, the MQL technology is studied to understand its effects on tool life and surface integrity in end milling of nuclear manufacturing grade stainless steels such as AISI316L. The milling experiments are performed using a robotic milling cell. The tool life is assessed by measuring the wear land using optical microscopy techniques, whereas the surface integrity is assessed in terms of surface residual stress (XRD) and surface roughness (optical metallography). The results show that MQL conditions and the oil type significantly affects the tool wear, tool life and surface integrity. Improve surface roughness was observed at 15 strokes/min at 75 ml/h of fluid flow rate. It was observed that high stroke rate with increased oil flow leads to decrease in the surface residual stress. It was found that use of synthetic MQL oils do not help to increase tool life compared to dry cutting. When water-based synthetic oils were used, the stable wear progress duration was found to be very short. [ABSTRACT FROM AUTHOR]

The calibration of digital recorders has special significance for the traceability of high voltage impulse measuring systems to the national or international references. Lightning impulse (LI) and switching impulse (SI) calibrators are the main important devices for this purpose. In a calibration of a digital recorder, the deviations of the peak value and time parameters according to the reference values are determined at different resolutions and each measuring range. The scale factor and the deviations of the time parameters of digital recorder result from a comparison of measured values with the corresponding reference values applied from the impulse calibrator. This paper summarizes the design, implementation and performance of a new design calculable impulse voltage calibrator. The constructed calibrator is used as a primary reference standard in National Metrology Institute of Turkey. The calibrator designed and implemented in this work is the primary reference for providing the lowest uncertainty in the traceability of lightning and switching pulses in the range between 50 V and 600 V between national high voltage laboratories affiliated to the International Bureau of Weights and Measures (BIPM). The estimated uncertainties of the LI calibrator are 0.03% for the peak value, (UP), 0.30% for the front time, (T1), and 0.10% for the time to half value, (T2). For the SI calibrator, they are 0.10% for the peak value, (UP), 0.20% for the front time, (T1), and 0.04% for the peak time value, (TP). [ABSTRACT FROM AUTHOR]

Software size measurement and effort estimation methodologies in use today usually take the detailed requirements of software to be developed as the primary input and a certain amount of time and expertise is needed for size measurement. This paper analyzes the open source projects'correlations between the problem domain measures (the number of nouns and verbs) and solution domain measures (the number of software classes and methods). In this paper, 27 open source software projects are analyzed. Linear regression and cross validation techniques are applied to investigate the relation between the sizes of problem domain (i.e., conceptual) and solution domain (i.e., design) measures. The results reveal a strong correlation between the problem domain measures and the solution domain measures constituting the corresponding software. The results suggest that it is possible to use problem domain descriptions in the early stages of software development projects to make plausible predictions for the size and effort of the software. [ABSTRACT FROM AUTHOR]

Energy storage technologies (EST) will have an important position in combination of renewable energy sources (RES) in modern electrical power systems and smart grid. EST can provide more balancing and flexibility to the power system, providing incorporation of intermittent RES to the smart grid. Energy storage technologies have a critical function to provide ancillary services in the generation mode for smart grid. This paper gives a short overview of the current energy storage technologies and their applications available and the opportunities and challenges the power systems faces for successful integration of RES to smart grid. This paper also discusses different types of EST experimentally tested in smart grid environment such as electrochemical batteries and ultra-capacitor energy storage systems. This paper is concluded by giving some important experimental results, recommendations and suggestions to whom, which are studying on different energy storage applications including battery and ultra-capacitors in the smart grid. [ABSTRACT FROM AUTHOR]

Web sites constitute the interface where e-businesses interact with their customers. Therefore, the quality of company web sites is instrumental for customer satisfaction. This paper proposes a solution to the problem of quality performance evaluation for web sites in the logistics industry. There exists no standard, widely accepted structure for analyzing the quality and performance of corporate web pages. On the other hand, a standardized evaluation method can help quickly compare and identify successfull web sites. For this purpose, an integrated approach based on Multi Criteria Decision Making (MCDM) and fuzzy logic is introduced in this paper, which aims to more effectively assess the quality of logictics firms' web sites. In the first part, web site evaluation criteria and their hierarchy are determined based on a detailed literature review and expert opinions. In the second part, the weights of the evaluation criteria are calculated with the fuzzy logic application of Analytical Hierarchy Process (AHP), an MCDM technique. In the final part, the web sites of the top 15 logictics companies in Turkey are ranked in decreasing quality, using fuzzy TOPSIS method. Furthermore, in order to assess how far the criteria weights have an impact on the ranking of the web sites, a sensitivity analysis is carried out. This study can be useful to researchers to better understand web site evaluation problemtheoretically, as well as to organizations in designing better satisfying web sites. [ABSTRACT FROM AUTHOR]

The flow noise generated by a generic underwater vehicle is modeled and solved in a numerical environment. By using the Large Eddy Simulation (LES), the hydrodynamic analysis is performed using the finite volume methods and the acoustic analogies modeling the sound propagation. Sound pressure levels, sound direction, noise spectra and acoustic trace are found in the fluid environment. In order to increase the accuracy, fine mesh structure was used and second order discretization was applied to the volume. By using the pressurebased commercial code, the flow dynamics equations are solved in filtering process and the pressure obtained from hydrodynamic solution is defined as an acoustic source. Along with this, in order to be able to verify the method, a numerical process was created which will be evaluated considering the experimental studies in the literature. The numerical results of the thrust and torque curves at different rpms and speeds for the 4382 propeller were compared with test data. In addition, the amplitude levels of the noise harmonics generated by the VP1304 propeller are obtained by hybrid method at the receivers in the numerical environment and the results are compared with the test data. With the verification of the current method, the noise characteristics of the underwater vehicle were found by the Lighthill-Curle method and the classification of noise sources was performed using hydrodynamic sources. Thus, the feasibility and application of current work, which is an important criterion in the design and development phases, has been demonstrated and developed in this paper. [ABSTRACT FROM AUTHOR]

In this paper, an improved method for detecting light-flicker from multiple flicker sources which has a significant detrimental effect on power quality for power systems is proposed. The proposed method calculates the instantaneous flicker value directly from the frequency spectrum of the voltage signal unlike the standard IEC-61000-4-15 flickermeter known to give erroneous results in case of deviation of the fundamental frequency. Besides, owing to spectral corrections, this can also obtain the correct flicker value when the fundamental frequency deviates. Tests with synthetic signals have been generated in the presence of a single interharmonic frequency for different values, multiple frequency components and fundamental frequency deviations respectively, and then the instantaneous flicker values calculated by this method have been compared with IEC-flickermeter results. The method has been also used to calculate the flicker of field data obtained from busbars feeding electric arc furnace plants in the Electricity Transmission System of Turkey and the flicker-severity results have been compared with the results of the IEC-flickermeter. The advantage of the method is that it can swiftly and precisely estimate the flicker because of the reduction of it to arithmetic operations on Fast Fourier Transform(FFT) samples already calculated in many power quality analyzers. [ABSTRACT FROM AUTHOR]

Turkey has gone through great changes with "Health Transformation Program" and made a substantial transformation. However, much statistical data have been recorded regarding the practices and behavior of hospitals in Turkey since the implementation of health transformation program. While these records pointed to various problems arising from the reforms, a methodological analysis is rarely found. Based on five years of province level health care data, this paper analyzes the productive efficiency of Turkey's health care sector in the post reform period. Efficiency measures are calculated by a nonparametric approach known as data envelopment analysis. Productivity between the years 2011 and 2015 is measured by the Malmquist index. Furthermore, in order to classify the provinces with the assessment value of 1; the super-efficiency model is applied for further sorting. According to the computed Malmquist index, results show that 51 provinces increased their productivity however 30 provinces decreased their productivity in Turkey's health care sector. On the other hand, by the evaluation of the results, it is seen that the level of economic development and the efficiency performance of hospitals could not necessarily act cooperatively. [ABSTRACT FROM AUTHOR]

In recent years, with Additive Manufacturing (AM) technology, which is used in many different areas, it is possible to manufacture 3D parts in complex form more easily, inexpensively and quickly than conventional methods. Among the AM technologies, the most popular and inexpensive method is Fused Deposition Modelling (FDM). Recently there is growing interest in direct manufacturing of final ready for use parts using this technology. However mechanical properties of the FDM printed parts are the main constraint preventing the widespred application of FDM printed parts. In order to apply AM extensively in the manufacture of finished parts, there is a need for improvements in existing techniques and materials to meet the mechanical requirements of the load-bearing components. This paper, for the first time, investigates feasibity of manufacturing and FDM 3D printing of 6 mm long carbon fibre reinforced acrylonitrilebutadiene-styrene (ABS) composite filaments. The part strength is shown to be significantly improved with 6 mm long carbon fibre reinforcement with the flexibility and processability of the fibres is diminishing with increasing reinforcement content. It has also been determined that the print pattern significantly affects the mechanical properties. [ABSTRACT FROM AUTHOR]

This paper investigates the delay-dependent stability of a micro-grid system with constant communication delay considering not only stability but also gain-phase margins (GPMs). A gain-phase margin tester is introduced to the micro-grid system as to take into GPMs in delay margin computation. A frequency domain analytical method, Rekasius substitution, is utilized to compute the GPMs based stability delay margins. The method aims to calculate all possible purely complex roots of the characteristic equation for a finite positive time delay. The approach first transforms the characteristic polynomial of the micro-grid system with transcendental terms into a regular polynomial. Routh-Hurwitz stability criterion is then implemented to compute the purely imaginary roots with the crossing frequency and stability delay margin. For a wide range of proportional-integral controller gains and GPMs, time delay values for which the micro-grid system is both stable and has desired stability margin measured by GPMs are computed. The accuracy of complex roots and delay margins are verified by using an independent algorithm, QPMR (the quasi-polynomial mapping-based root finder) algorithm and time-domain simulations, respectively. Simulation studies indicate that delay margins must be determined by considering GPMs to have a better dynamic performance in term of fast damping of oscillations, less overshoot and shorter settling time. [ABSTRACT FROM AUTHOR]

Virtual local area network (VLAN)'s are being created for improve performance, easy to manage security and ensure address on local area networks. This paper introduces a new approach for load balancing on virtual local area networks. The method which is developed for this approach, is dynamically changing the clients ports VLAN membership according to VLAN's total traffic of the same security policy. The clients which have to register to security VLAN, can access their permission level source at all physically location of LAN, this is the flexibility of the method. The VLAN count which have to be on the LAN, can adjust parametrically or default constantly. In the algorithm which developed for this approach, the hosts belong to traffic on the network, ensures as much as possible equal or nearest distributes homogeneous on the VLAN's. In this way the VLAN's have same or nearest traffic value. A software has developed for testing functionality of this method which using SNMP protocol and reached to the aims by testing on the real network. [ABSTRACT FROM AUTHOR]

The flow noise generated by a generic underwater vehicle is modeled and solved in a numerical environment. By using the Large Eddy Simulation (LES), the hydrodynamic analysis is performed using the finite volume methods and the acoustic analogies modeling the sound propagation. Sound pressure levels, sound direction, noise spectra and acoustic trace are found in the fluid environment. In order to increase the accuracy, fine mesh structure was used and second order discretization was applied to the volume. By using the pressure-based commercial code, the flow dynamics equations are solved in filtering process and the pressure obtained from hydrodynamic solution is defined as an acoustic source. Along with this, in order to be able to verify the method, a numerical process was created which will be evaluated considering the experimental studies in the literature. The numerical results of the thrust and torque curves at different rpms and speeds for the 4382 propeller were compared with test data. In addition, the amplitude levels of the noise harmonics generated by the VP1304 propeller are obtained by hybrid method at the receivers in the numerical environment and the results are compared with the test data. With the verification of the current method, the noise characteristics of the underwater vehicle were found by the Lighthill-Curle method and the classification of noise sources was performed using hydrodynamic sources. Thus, the feasibility and application of current work, which is an important criterion in the design and development phases, has been demonstrated and developed in this paper. [ABSTRACT FROM AUTHOR]

Turkey has gone through great changes with "Health Transformation Program" and made a substantial transformation. However, much statistical data have been recorded regarding the practices and behavior of hospitals in Turkey since the implementation of health transformation program. While these records pointed to various problems arising from the reforms, a methodological analysis is rarely found. Based on five years of province level health care data, this paper analyzes the productive efficiency of Turkey's health care sector in the post reform period. Efficiency measures are calculated by a nonparametric approach known as data envelopment analysis. Productivity between the years 2011 and 2015 is measured by the Malmquist index. Furthermore, in order to classify the provinces with the assessment value of 1; the super-efficiency model is applied for further sorting. According to the computed Malmquist index, results show that 51 provinces increased their productivity however 30 provinces decreased their productivity in Turkey's health care sector. On the other hand, by the evaluation of the results, it is seen that the level of economic development and the efficiency performance of hospitals could not necessarily act cooperatively. [ABSTRACT FROM AUTHOR]

Selection of reasonable cutting parameters (cutting speed, feed rate and depth of cut) is important in order to obtain required surface quality in turning operations. In this paper, in addition to cutting parameters,the effects of work piece dimensions (overhang length and diameter) on the surface roughness are investigated experimentally and surface roughness predicition models are developed from the experimental results. Feed rate, cutting speed, depth of cut and overhang lenghts are taken as vaiable parameters for the work pieces at two different diameters machined on a CNC lathe. A total of 34 =81 different cutting experiments have been performed for the work pieces (for each diameter) based on the three-level full factorial design of experiments. Using the results from the experiments, models have been developed for the prediction of surface roughnessq based on Adaptive Neuro-Fuzzy Inference System(ANFIS). The best model is selected for each diameter. These models are considered as a guide for metal removing industry environment in order to obtain a desired surface qualiy. [ABSTRACT FROM AUTHOR]

In recent years, with Additive Manufacturing (AM) technology, which is used in many different areas, it is possible to manufacture 3D parts in complex form more easily, inexpensively and quickly than conventional methods. Among the AM technologies, the most popular and inexpensive method is Fused Deposition Modelling (FDM). Recently there is growing interest in direct manufacturing of final ready for use parts using this technology. However mechanical properties of the FDM printed parts are the main constraint preventing the widespred application of FDM printed parts. In order to apply AM extensively in the manufacture of finished parts, there is a need for improvements in existing techniques and materials to meet the mechanical requirements of the load-bearing components. This paper, for the first time, investigates feasibity of manufacturing and FDM 3D printing of 6 mm long carbon fibre reinforced acrylonitrile-butadiene-styrene (ABS) composite filaments. The part strength is shown to be significantly improved with 6 mm long carbon fibre reinforcement with the flexibility and processability of the fibres is diminishing with increasing reinforcement content. It has also been determined that the print pattern significantly affects the mechanical properties. [ABSTRACT FROM AUTHOR]

This paper investigates the delay-dependent stability of a micro-grid system with constant communication delay considering not only stability but also gain and phase margins (GPMs). A gain-phase margin tester (GPMT) is introduced to the micro-grid system as to take into GPMs in delay margin computation. A frequency domain analytical method, Rekasius substitution, is utilized to compute the GPMs based stability delay margins. The method aims to calculate all possible purely complex roots of the characteristic equation for a finite positive time delay. The approach first transforms the characteristic polynomial of the micro-grid system with transcendental terms into a regular polynomial. Routh-Hurwitz stability criterion is then implemented to compute the purely imaginary roots with the crossing frequency and stability delay margin. For a wide range of proportional - integral (PI) controller gains and GPMs, time delay values for which the micro-grid system is both stable and has desired stability margin measured by GPMs are computed. The accuracy of complex roots and delay margins are verified by using an independent algorithm, the quasi-polynomial mapping-based root finder (QPmR) and time-domain simulations, respectively. Simulation studies indicate that delay margins must be determined by considering GPMs to have a better dynamic performance in term of fast damping of oscillations, less overshoot and shorter settling time. [ABSTRACT FROM AUTHOR]

Virtual local area network (VLAN)'s are being created for improve performance, easy to manage security and ensure address on local area networks. This paper introduces a new approach for load balancing on virtual local area networks. The method which is developed for this approach, is dynamically changing the clients ports VLAN membership according to VLAN's total traffic of the same security policy. The clients which have to register to security VLAN, can access their permission level source at all physically location of LAN, this is the flexibility of the method. The VLAN count which have to be on the LAN, can adjust parametrically or default constantly. In the algorithm which developed for this approach, the hosts belong to traffic on the network, ensures as much as possible equal or nearest distributes homogeneous on the VLAN's. In this way the VLAN's have same or nearest traffic value. A software has developed for testing functionality of this method which using SNMP protocol and reached to the aims by testing on the real network. [ABSTRACT FROM AUTHOR]

Academic timetabling problems a class of NP-Hard type problem which cannot be solved in polynomial time. In literature, these problems are studied under two different main topics which are curriculum and post-enrollment based timetabling problems. In this paper, curriculum based timetabling problem is entirely reviewed then timetabling procedure of Atatürk University Engineering Faculty is analyzed. The problem which is handled in this paper is not only a lean lecture assigning problem but also including several constraints related to lecture given departments and classes (student groups). In this study an integer linear model is proposed to maximize the satisfaction of teaching staff from timetable according to their appellation and numerical results, obtained from solution of a small sized sample, are evaluated. [ABSTRACT FROM AUTHOR]

One of the most important operational decisions in the logistics management is to determine the vehicle routes serving the customers. The Vehicle Routing Problem (VRP) can be defined as the determination of the optimal routes which meet the delivery (or pickup) demands from the depot to the customers. In the real life applications of logistics, vehicles in a fleet may differ from each other. In addition, the requirements arising from customers/goods may reveal the necessity to use different vehicles. Besides, companies do care more about the management of reverse flow of products, semi-finished and raw materials because of their economic benefits and as well as legal and environmental liabilities. In this paper, a variant of the VRP is considered with heterogeneous fleet of vehicles and simultaneous pickup and delivery. This problem is referred to Heterogeneous Vehicle Routing Problem with Simultaneous Pickup and Delivery (HVRPSPD). The HVRPSPD can be defined as determining the routes and the vehicle types on each route while minimizing the total cost. In this paper, a polynomial sized flow-based mathematical model is proposed for the HVRPSPD. Since the HVRPSPD is in the class of NP-hard problems, it is difficult to find the optimal solution in a reasonable time even for the moderate size problems. Therefore, a simple and constructive heuristic algorithm is proposed to solve the medium and large scale HVRPSPD s. This algorithm is the adaptation of very well-known Clarke-Wright Savings approach, which has originally developed for the VRP, to the HVRPSPD. The performances of the proposed mathematical model and the heuristic algorithm have been examined on the test problems. [ABSTRACT FROM AUTHOR]

In 1971, memristor is claimed as a missing circuit element and almost 40 years later than its prediction a memristive system behaving as a memristor has been found in 2008. Memristor is accepted by many as the new and the fourth fundamental circuit element. Analog applications of memristor have emerged as a new research area in recent years. An analog filter with memristor can have automatically adjustable gain, quality factor and bandwidth characteristics etc. thanks to its variable memristance. In this paper, two different types of secondorder Sallen-Key filters, which are the low-pass and the high-pass Sallen Key filters, are analyzed using simulations. The linear drift model of TiO2 memristor is used in all analysis and simulations. It has been found that the memristor in the filters can go into saturation at very low frequencies and both of the filters operate well at higher frequencies. A criterion is suggested to prevent memristor from going into saturation and to prevent distortion at low frequencies. Using the criteria and choosing a memristor with more appropriate parameters, the simulations are repeated for the low-pass filter and it is shown that the low-pass filter operates better with the new parameters chosen. The analysis and the criteria given in this paper can be used to design memristor-based Sallen-Key filters and adaptable to other memristor-based filters as well. [ABSTRACT FROM AUTHOR]

Power quality (PQ) problems have become a serious concern of both power suppliers and end user customers with the deregulation of the electric power market. In the recent years, power electronics based compensation devices with advanced technology has been required due to the inadequate of conventional compensation devices to improve PQ in utility grid. This paper presents a comprehensive review of shunt compensating custom power devices (CPD) connected to distribution system mainly Distribution Synchronous Static Compensator (DSTATCOM) and Active Power Filter (APF). A broad overview on various control methods to compansate different PQ problems used in DSTATCOM and APF's and the main operation principles of these devices are provided. The practical applications and recent research advances on DSTATCOM and APF's are presented by reviewing nearly 120 papers. [ABSTRACT FROM AUTHOR]

Water treatment methods, as part of the peripheral units of a novel electrochemical machining device, were investigated with the aim of preparing the electrolyte, which was contaminated with heavy metal ions after machining of copper work pieces, for refeeding back to the system. Electrochemical machining (ECM) depends on machining the surface of a metal piece by ionization and removal of metal ions from the work area via the electrolyte. Removal of heavy metal ions in industrial waters and treatment of these waters for reuse is crucial in terms of increasing system efficiency and protecting environmental health. In this study, the ion exchange method was selected and a three-step application is proposed for the treatment of the electrolyte contaminated with copper ions after ECM. As the ion-exchanger, a paper filter was used in the first step, a natural zeolite with wide reserves in Turkey was used in the second step, and a polymer based cation exchange Lewatit TP 207 resin was used in the final step. Purification of the electrolyte, contaminated with copper ions, was achieved at 40 % as a result of treatment with the zeolite for two hours, at 90 % as a result of filtering three times using the paper filters, and at 100 % after treatment with the Lewatit TP 207 resin. [ABSTRACT FROM AUTHOR]

This paper presents flow-structure interaction between a sphere wake and a free water surface for different submerged elevations in an open water channel for Reynolds numbers in the range of 2.5x103 ≤Re≤1x104 based on the diameter of the sphere. Particle Image Velocimetry (PIV) and dye visualization techniques were performed to demonstrate flow patterns such as instantaneous and time-averaged velocity field, streamline topology, vortices, velocity contours. The sphere was fixed at various submerged locations from the piercing the free surface case to the two sphere diameters beneath the free surface in the range of 0.25≤ h/D ≤3.0. Here, submerged ratio was defined as ratio of bottom shoulder of the sphere from the free surface to the sphere diameter. Depending on the sphere locations, characteristics of wake region exhibit three different flow phenomena. These are classified as; a restricted wake region between the free-surface and uniform flow stream for the submerged ratios of 0.25≤ h/D ≤1.0, unsymmetrical flow patterns due to the free surface effect for the submerged ratios of 1.25≤ h/D ≤2.0 and symmetrical flow structures for the submerged ratios of 2.5≤ h/D ≤3.0. More detailed results for the aforementioned flow structures from the point of flow physics were comparatively presented and interpreted. [ABSTRACT FROM AUTHOR]

In this study, we propose a novel cooling dehumidifying strategy, in which a condensing panel can be hydronically connected in series with the radiant cooling system to overcome condensation risk and improve indoor thermal comfort level. Based on the concept, the sensible heat-load is primarily covered by radiant cooling panels and some amount of latent heat and sensible heat can be treated by the condensing panel, while improving indoor thermal comfort level. Since, the surface temperature of the condensing panel is lower than the dew point temperature, while the radiant surface is higher for same supply water temperatures - condensation occurs only over the condensing plate. This paper evaluates the thermal comfort performance of the proposed novel condensing panel. For these aim, a new experimental chamber was developed. General thermal comfort level and the temperature, relative humidity ratio distribution in the tested room were evaluated for 10 different experimental cases. Multiple tests were conducted by varying surface temperature of the condensing panel and initial relative humidity ratios of air in the room. The results show that proposed simple solution can improve thermal comfort level, for the places where the latent heat loads are not considerable high, and reduce the condensation risk over the radiant cooling panels. [ABSTRACT FROM AUTHOR]

Many research projects are being conducted regarding additive manufacturing technologies, which help widen their application field for the manufacturing of functional metallic parts. Additive manufacturing technologies differ in many ways, such as the form of the material used, the material addition technique employed, the type of the energy input and the process configuration. Among these, laser additive manufacturing is preferred by industry due to their flexibility for new material types, the ability to produce small geometrical features and better surface quality compared to the other methods. However, due to the rapid melting and solidification processes inherent in this method, the internal stresses increase, deformations occur, and therefore, high quality products cannot be obtained depending on the geometry and the material selection. It is only possible to overcome these challenges by optimizing the process in terms of different parameters. However, it is not feasible in terms of time and cost to understand the effects of dozens of different parameters on the relevant process by a single investigator or an institution. For this reason, in this paper different studies in the literature have been systematically reviewed, the parameters used in the process have been explained, the challenges encountered in different cases have been pointed out, and the improvements made in the process parameters have been revealed. [ABSTRACT FROM AUTHOR]

Design of structures with inelastic behaviour under seismic loading conditions is an important issue for engineers. For this reason, amplification factors defined in modern seismic codes are used to reduce the elastic seismic force demand and estimate the actual displacements. Although these factors play an important role in seismic codes, the format and also ratios between them have varied considerably from one code to another. In this paper, the first objective is to investigate the amplified seismic loads in design requirements. Based on this derivation, the second objective is to evaluate their accuracy. For this purpose, considering the increase in the axial load levels on columns, system overstrength factors for Special Moment Resisting Frames (SMRFs) under strong ground motions are examined. The results are presented in as maximum and average maximum axial load amplification factors, plastic hinge rotations and system overstrength factors under selected ground motions. [ABSTRACT FROM AUTHOR]

Selection of reasonable cutting parameters (cutting speed, feed rate and depth of cut) is important in order to obtain required surface quality in turning operations. In this paper, in addition to cutting parameters,the effects of work piece dimensions (overhang length and diameter) on the surface roughness are investigated experimentally and surface roughness predicition models are developed from the experimental results. Feed rate, cutting speed, depth of cut and overhang lenghts are taken as vaiable parameters for the work pieces at two different diameters machined on a CNC lathe. A total of 34 =81 different cutting experiments have been performed for the work pieces (for each diameter) based on the three-level full factorial design of experiments. Using the results from the experiments, models have been developed for the prediction of surface roughness based on Adaptive Neuro-Fuzzy Inference System(ANFIS). The best model is selected for each diameter. These models are considered as a guide for metal removing industry environment in order to obtain a desired surface qualiy. [ABSTRACT FROM AUTHOR]

In recent years, with Additive Manufacturing (AM) technology, which is used in many different areas, it is possible to manufacture 3D parts in complex form more easily, inexpensively and quickly than conventional methods. Among the AM technologies, the most popular and inexpensive method is Fused Deposition Modelling (FDM). Recently there is growing interest in direct manufacturing of final ready for use parts using this technology. However mechanical properties of the FDM printed parts are the main constraint preventing the widespred application of FDM printed parts. In order to apply AM extensively in the manufacture of finished parts, there is a need for improvements in existing techniques and materials to meet the mechanical requirements of the load-bearing components. This paper, for the first time, investigates feasibity of manufacturing and FDM 3D printing of 6 mm long carbon fibre reinforced acrylonitrile-butadiene-styrene (ABS) composite filaments. The part strength is shown to be significantly improved with 6 mm long carbon fibre reinforcement with the flexibility and processability of the fibres is diminishing with increasing reinforcement content. It has also been determined that the print pattern significantly affects the mechanical properties. [ABSTRACT FROM AUTHOR]

This paper investigates the delay-dependent stability of a micro-grid system with constant communication delay considering not only stability but also gain and phase margins (GPMs). A gain-phase margin tester (GPMT) is introduced to the micro-grid system as to take into GPMs in delay margin computation. A frequency domain analytical method, Rekasius substitution, is utilized to compute the GPMs based stability delay margins. The method aims to calculate all possible purely complex roots of the characteristic equation for a finite positive time delay. The approach first transforms the characteristic polynomial of the micro-grid system with transcendental terms into a regular polynomial. Routh-Hurwitz stability criterion is then implemented to compute the purely imaginary roots with the crossing frequency and stability delay margin. For a wide range of proportional - integral (PI) controller gains and GPMs, time delay values for which the micro-grid system is both stable and has desired stability margin measured by GPMs are computed. The accuracy of complex roots and delay margins are verified by using an independent algorithm, the quasi-polynomial mapping-based root finder (QPmR) and time-domain simulations, respectively. Simulation studies indicate that delay margins must be determined by considering GPMs to have a better dynamic performance in term of fast damping of oscillations, less overshoot and shorter settling time. [ABSTRACT FROM AUTHOR]

Virtual local area network (VLAN)'s are being created for improve performance, easy to manage security and ensure address on local area networks. This paper introduces a new approach for load balancing on virtual local area networks. The method which is developed for this approach, is dynamically changing the clients ports VLAN membership according to VLAN's total traffic of the same security policy. The clients which have to register to security VLAN, can access their permission level source at all physically location of LAN, this is the flexibility of the method. The VLAN count which have to be on the LAN, can adjust parametrically or default constantly. In the algorithm which developed for this approach, the hosts belong to traffic on the network, ensures as much as possible equal or nearest distributes homogeneous on the VLAN's. In this way the VLAN's have same or nearest traffic value. A software has developed for testing functionality of this method which using SNMP protocol and reached to the aims by testing on the real network. [ABSTRACT FROM AUTHOR]

In this study, we propose a novel cooling dehumidifying strategy, in which a condensing panel can be hydronically connected in series with the radiant cooling system to overcome condensation risk and improve indoor thermal comfort level. Based on the concept, the sensible heat-load is primarily covered by radiant cooling panels and some amount of latent heat and sensible heat can be treated by the condensing panel, while improving indoor thermal comfort level. Since, the surface temperature of the condesing panel is lower than the dew point temperature, while the radiant surface is higher for same supply water temperatures - condensation occurs only over the condesing plate. This paper evaluates the thermal comfort performance of the proposed novel condensing panel. For these aim, a new experimental chamber was developed. General thermal comfort level and the temperature, relative humidity ratio distribution in the tested room were evaluated for 10 different experimental cases. Multiple tests were conducted by varying surface temperature of the condensing panel and initial relative humidity ratios of air in the room. The results show that proposed simple solution can improve thermal comfort level, for the places where the latent heat loads are not considerable high, and reduce the condensation risk over the radiant cooling panels. [ABSTRACT FROM AUTHOR]