Energy savings in simultaneous multi-threaded processors through dynamic resizing of datapath resources

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

Design, optimization, and realization of a wire antenna with a 25:1 bandwidth ratio for terrestrial communications

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

Dynamics, stability, and actuation methods for powered compass gait walkers

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

Last level cache partitioning via multiverse thread classi cation

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

Weak penetration and radiation through apertures in conducting bodies of revolution

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

A corpus-based concatenative speech synthesis system for Turkish

Sak, Haşim | Güngör, Tunga | Safkan, Yaşar

Article | 2006 | Turkish Journal of Electrical Engineering and Computer Sciences14 ( 2 ) , pp.209 - 223

Speech synthesis is the process of converting written text into machine-generated synthetic speech. Concatenative speech synthesis systems form utterances by concatenating pre-recorded speech units. Corpus-based methods use a large inventory to select the units to be concatenated. In this paper, we design and develop an intelligible and natural sounding corpus-based concatenative speech synthesis system for the Turkish language. The implemented system contains a front-end comprised of text analysis, ,phonetic analysis, and optional use of transplanted prosody. The unit selection algorithm is based on commonly used Viterbi decoding a . . .lgorithm of the best-path in the network of the speech units using spectral discontinuity and prosodic mismatch objective cost measures. The back-end is the speech waveform generation based on the harmonic coding of speech and overlap-and-add mechanism. Harmonic coding enabled us to compress the unit inventory size by a factor of three. In this study, a Turkish phoneme set has been designed and a pronunciation lexicon for root words has been constructed. The importance of prosody in unit selection has been investigated by using transplanted prosody. A Turkish Diagnostic Rhyme Test (DRT) word list that can be used to evaluate the intelligibility of Turkish Text-to-Speech (TTS) systems has been compiled. Several experiments have been performed to evaluate the quality of the synthesized speech and we obtained 4-2 Mean Opinion Score (MOS) in the listening tests for our system, which is the first unit selection based system published for Turkish Daha fazlası Daha az

Turkish entity discovery with word embeddings

Kalender, Murat | Korkmaz, Emin Erkan

Other | 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 entitie Daha fazlası Daha az

A platform for software engineering course projects

Aygün, Birol

Other | 2004 | Turkish Journal of Electrical Engineering and Computer Sciences12 ( 2 ) , pp.107 - 116

The importance of projects in software engineering courses is well known. Both synthetic and real-life projects have various advantages and disadvantages. Our aim was to create a framework where students can develop projects which reflect some of the complexities of real-life, involving many concurrent, interacting, asynchronous processes, each in a different stage of development, with wide temporal differences among them - some occurring- within millisconds of each other and others executing sporadically over much longer periods. In this project, which was carried out in different arrangements in several software engineering course . . .s in three universities, the students developed both the sub- and super-structures required, with varying degrees of success. The projects were performed in parallel with and subsequent to one-semester courses in software engineering. The development was performed in accordance with the principles established in the lectures. The sub-structure consists of a discrete-time event simulator and a message passing mechanism. It can support many different super-structures. The super-structure we created was an e-business community simulator where a manufacturer, its trading partners and the transactions among them were simulated. In this paper we summarize the project and our experiences during the development. A literature search for similar projects for software engineering education did not yield any hits. However several reported industrial projects for virtual supply chain management were examined. Our project on the other hand was tailored for implementation by student groups in one semester with the primary purpose of getting experience in complex, multi-group software development rather than immediate industrial use of the software Daha fazlası Daha az

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