Kalender, M. | Korkmaz, E.E.

Article | 2017 | Turkish Journal of Electrical Engineering and Computer Sciences25 ( 3 ) , pp.2388 - 2398

Entity-linking systems link noun phrase mentions in a text to their corresponding knowledge base entities in order to enrich a text with metadata. Wikipedia is a popular and comprehensive knowledge base that is widely used in entity-linking systems. However, long-tail entities are not popular enough to have their own Wikipedia articles. Therefore, a knowledge base created by using Wikipedia entities would be limited to only popular entities. In order to overcome the knowledge base coverage limitation of Wikipedia-based entity-linking systems, this paper presents an entity-discovery system that can detect semantic types of entities t . . .hat are not defined in Wikipedia. The effectiveness of the proposed system was validated empirically through the use of generated data sets for the Turkish language. The experimental results show that, in terms of accuracy, our system performs competitively in comparison to the previous methods in the literature. Its high performance is achieved through a method that learns word embeddings for candidate entities. © TÜBİTAK Daha fazlası Daha az

Canbay, C. | Palak, Ö. | Kallem, A.

Article | 2019 | Turkish Journal of Electrical Engineering and Computer Sciences27 ( 1 ) , pp.37 - 45

This study aims to elucidate the production mechanism of cytokine-like formations secreted from T cells and similar cells by electromagnetic modeling techniques. Three Hertz dipole antennas polarized in arbitrary directions were placed without touching each other at the center of spherical T-cell models to test the Canbay hypothesis about the formation mechanism of cytokines (CHAFMOC) on T-cell surfaces. A dielectrophoretic force field was created within the gelatin layer of the T-cell model. The prepared control and electromagnetically stimulated T-cell model samples were incubated in water in a glass container in a Faraday cage fo . . .r the specified period and then photographed. At the end of the experiments, cytokine-like formations were observed in the samples, depending on their contents. The results of these experiments, carried out in accordance with the CHAFMOC, show that a dielectrophoretic force is the main cause of the cytokine formation and secretion mechanism in the outer layers of rough T-cell models. Given these results, new approaches and developments may be expected to better our understanding of the immune system in the subjects of cell science, pharmacology, and bioengineering. © TÜBİTAK Daha fazlası Daha az

Küçük, Gürhan | Mesta, Mine

Article | 2012 | Turkish Journal of Electrical Engineering and Computer Sciences20 ( 1 ) , pp.125 - 139

Nowadays, all the designers of systems from high-performance servers to battery-operated handheld devices aim for reliability, high-performance and longevity. Central within these aims the issue of processor power consumption is becoming increasingly important. In this study, we aim to adapt our already-provenmethod for single-threaded superscalar processors to simultaneous multi-threaded (SMT) processors for energy savings. The original method focused on resizing datapath resources according to the demands of running applications. To achieve this, the targeted resources are physically divided into multiple partitions, and turned on . . . and off according to the needs of the applications. Since, the energy consumption of the turned-off datapath resources is quite low, as a result, it becomes possible to have great amount of energy savings within a processor. However, special care must be taken when there are multiple threads racing against each other to gain access to shared datapath resources. As a result, our proposed microarchitectural technique achieves 0.5% Instructions Per Cycle (IPC) and 3.2% Total number of instructions Per Cycle (TPC) improvement, while it turns off 45% of the Reorder Buffer (ROB), 59% of the Load-Store Queue (LSQ), 43% of the Issue Queue (IQ), 30% of the integer Physical Register Files (PRF) and, finally, 48% of the floating PRF, on the average across all simulated benchmarks. According to our estimates, the total processor power is reduced by 12%, on the average Daha fazlası Daha az

Yeğin, Korkut

Article | 2014 | Turkish Journal of Electrical Engineering and Computer Sciences22 ( 2 ) , pp.371 - 379

Wire antennas can be made wideband if the antenna is loaded with passive elements and connected to a lossless matching network. However, realization of the load component values and matching network can easily become impractical. In this study, using only a surface mount and standard component values, antenna loads and a matching network are optimized using genetic algorithms. The optimized design achieves a 25:1 bandwidth ratio, from 20 MHz to 500 MHz, with a maximum voltage standing wave ratio (VSWR) of 3.5 and minimum system gain of --5 dBi. The antenna system gain at azimuth is taken as the objective function and an exact penalt . . .y function is formulated to take into account the VSWR over the design frequency band. A loaded antenna is built and measured to corroborate the simulations results. The realized antenna is only 0.14 lambda long at 20 MHz Daha fazlası Daha az

Ovant, B.S. | Güney, I.A. | Savaş, M.E. | Kücük, G.

Article | 2018 | Turkish Journal of Electrical Engineering and Computer Sciences26 ( 1 ) , pp.220 - 233

Last level caches (LLCs) are part of the last line of defense against the famous memory wall problem. Today, almost all processors utilize a LLC for the same reason. This study extends our previous work, which proposed a cache-partitioning mechanism using thread classification. Here, we propose three enhancements to the existing system: 1) an adaptive traffic threshold mechanism for more portable classification hardware, 2) a new method for classifying way-hungry threads, and finally, 3) a thorough comparison of two design alternatives. Compared to the original way- partitioning mechanism, we show that the proposed mechanism's perfo . . .rmance improved by around 6%, on average. © 2018 TÜBITAK Daha fazlası Daha az

Şafak, Koray Kadir

Article | 2014 | Turkish Journal of Electrical Engineering and Computer Sciences22 ( 6 ) , pp.1611 - 1624

In this paper, methods to achieve actively powered walking on level ground using a simple 2-dimensional walking model (compass-gait walker) are explored. The walker consists of 2 massless legs connected at the hip joint, a point mass at the hip, and an infinitesimal point mass at the feet. The walker is actuated either by applying equal joint torques at the hip and ankle, by an impulse applied at the toe off, immediately before the heel strike, or by the combination of both. It is shown that actuating the walker by equal joint torques at the hip and ankle on level ground is equivalent to the dynamics of the passive walker on a downh . . .ill slope. The gait cycle for the simplified walker model is determined analytically for a given initial stance angle. Stability of the gait cycle by an analytical approximation to the Jacobian of the walking map is calculated. The results indicate that the short-period cycle always has an unstable eigenvalue, whereas stability of the long-period cycle depends on selection of the initial stance angle. The effect of the torso mass by adding a third link attached at the hip joint is investigated. The torso link is kept in the vertical position by controlling the torque applied to it. The proportional-derivative control law is utilized to regulate the angular position error of the torso link. Using linearized dynamics for this walker, active control is applied to the ankle, which reduces the dynamics of the walker to the passive walker without the torso. The proposed walker is capable of producing stable walking while keeping the torso in an upright positio Daha fazlası Daha az

Ovant, Burak Sezin | Güney, Isa Ahmet | Savaş, Muhammed Emin | Küçük, Gürhan

Article | 2018 | Turkish Journal of Electrical Engineering and Computer Sciences26 ( 1 ) , pp.220 - 233

http://www.trdizin.gov.tr/publication/paper/detail/TWpVMU5qSXlNZz09 https://hdl.handle.net/20.500.11831/5334

Canbay, C.

Article | 2019 | Turkish Journal of Electrical Engineering and Computer Sciences27 ( 6 ) , pp.4354 - 4360

Frequent use of magnetic resonance imaging (MRI) devices, which are major contributors in understanding health problems in the human body, is a subject that needs to be taken into consideration both for patients and for operators who are constantly in the vicinity of devices. In this context, electromagnetic impact assessment of an MRI device was performed at the point where the patient entered the device. Dielectrophoretic fields induced by radio frequency (RF) coils of an MRI scanner on male and female operator brain models were computed by using dispersive electrical medium parameters. The main cause of induced secondary dielectr . . .ophoretic fields by the RF coils of the MRI scanner is the veins modelled as monopole antennas on the lateral ventricle. The results explain that the dielectrophoretic fields near the veins on the ependymal surfaces are the main cause of Dawson fingers that may develop in the brains of multiple sclerosis (MS) patients and people at risk of the disease. Due to the use of the phantom results and the dispersive values of the electrical medium parameters, the results can be said to be close to the actual values and reliable. Therefore, the study will contribute to the confirmation of the hypotheses, developed by the author from a different perspective, related to the etiology of MS and will provide an accurate understanding of the concept of radiologically isolated syndrome. Everyone, including MRI designers, neurologists, radiologists, operators, and MS patients, can find any of the original information about MS that they need. © TÜBİTA Daha fazlası Daha az

Maşazade, E. | Bakir, A.K. | Kirci, P.

Article | 2019 | Turkish Journal of Electrical Engineering and Computer Sciences27 ( 2 ) , pp.1198 - 1212

The rainfall amount observed at a given location mostly depend on the cloud density, which can be quantified with the reflectivity values observed by meteorology weather radars. In this study, we aim to estimate the rainfall amount using a Kalman filter with radar reflectivity measurements. We first assume that the amount of rainfall observed at automatic weather observation stations (AWOSs) are elements of an unknown state vector and consider the Kalman filter process model as the true rainfall amounts observed at these AWOSs over time. For the measurement model of the Kalman filter, we use the radar reflectivity values observed at . . . each AWOS location. For the execution of the Kalman filter, a number of rainfall amount and radar reflectivity value pairs are first required to learn the process and measurement models of the Kalman filter. The estimation performance of the proposed Kalman filter is then compared with empirical reflectivity (Z) - rainfall (R) relationships. Numerical results show that when the Kalman filter is executed with radar reflectivity measurements observed around a large number of AWOS locations, the mean squared errors of the Kalman filter rainfall estimates are smaller than the ones obtained with empirical ZR relationships. © TÜBİTAK Daha fazlası Daha az

Yeğin, Korkut

Article | 2009 | Turkish Journal of Electrical Engineering and Computer Sciences17 ( 3 ) , pp.231 - 239

The simplest way to solve for penetration through small apertures in conducting surfaces is to treat the body as a scatterer and determine the interior field as the sum of the incident field and the scattered field contributed by the current induced on the surface of the body. However, it is well known that, if the aperture is very small or if the penetrated field is very weak this method yields very inaccurate results, which, in turn, prohibits proper design of electronic systems, especially for electromagnetic compatibility and interference. Previously, alternative integral equations formulations were proposed to remedy this probl . . .em and applied to two-dimensional conducting cylinders with slots [1–2]. Application of these alternative techniques to threedimensional conducting bodies of revolution (BOR) is studied in this work. In addition, the reciprocity principle is used to recast a weak penetration problem into a weak radiation problem, and it is shown that the alternative formulations useful for weak penetration are also useful for weak radiation. The important features and relative accuracies of each formulation together with numerical results are detailed for mock missile-shape structures Daha fazlası Daha az

Güney, I.A. | Küçük, G.

Article | 2019 | Turkish Journal of Electrical Engineering and Computer Sciences27 ( 6 ) , pp.4269 - 4283

As contemporary processors utilize more and more cores, cache partitioning algorithms tend to preserve cache associativity with a finer-grain of control to achieve higher throughput and fairness goals. In this study, we propose a scalable set-based cache partitioning mechanism, which welds an allocation policy and an enforcement scheme together. We also propose a set-based classifier to better allocate partitions to more deserving threads, a fast set redirection logic to map accesses to dedicated cache sets, and a double access mechanism to overcome the performance penalty due to a repartitioning phase. We compare our work to the be . . .st line-grain cache partitioning scheme that is available in the literature. Our results show that set-based partitioning improves throughput and fairness by 5.6% and 4.8% on average, respectively. The maximum achievable gains are as high as 33% in terms of throughput and 23% in terms of fairness. © TÜBİTA Daha fazlası Daha az

Gök, M.Y. | Gören Ugurdag, S. | Ünsalan, Cem | Sagirôglu, M.Ş.

Article | 2018 | Turkish Journal of Electrical Engineering and Computer Sciences26 ( 2 ) , pp.721 - 731

Next-generation sequencing generates large numbers of short reads from DNA. This makes it difficult to process and store. Therefore, efficient sequence alignment and mapping techniques are needed in bioinformatics. Alignment and mapping are the basic steps involved in genetic data analysis. The Smith{Waterman (SW) algorithm, a well-known dynamic programming algorithm, is often used for this purpose. In this work, we propose to utilize Phred quality scores in Gotoh's affine gap model to increase the accuracy and sensitivity of the SW algorithm. Hardware platforms such as FPGAs and GPUs are commonly used to solve computationally expen . . .sive problems. In this work, a hybrid PC-FPGA system is built where the SW algorithm based on the affine gap model with Phred quality scores is implemented on the FPGA and a read compressor is implemented on the host PC. We compare our method with state-of-the-art systems such as Bowtie, BWA, and the Kim{Olson FPGA-based system in terms of sensitivity, accuracy, and speed. Based on extensive experiments, we observed that our proposed method is more sensitive and accurate as compared to other solutions. © TUBITAK Daha fazlası Daha az