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Yayın On the sensitivity of desirability functions for multiresponse optimization(American Institute of Mathematical Sciences, 2008-11) Aksezer, Sezgin ÇağlarDesirability functions have been one of the most important multiresponse optimization technique since the early eighties. Main reasons for this popularity might be counted as the convenience of the implementation of the method and it's availability in many experimental design software packages. Technique itself involves somehow subjective parameters such as the importance coefficients between response characteristics that are used to calculate overall desirability, weights used in determining the shape of each individual response and the size of the specification band of the response. However, the impact of these sensitive parameters on the solution set is mostly uninvestigated. This paper proposes a procedure to analyze the sensitivity of the important characteristic parameters of desirability functions and their impact on pareto-optimal solution set. The proposed procedure uses the experimental design tools on the solution space and estimates a prediction equation on the overall desirability to identify the sensitive parameters. For illustration, a classical desirability example is selected from the literature and results are given along with the discussion.Yayın A survey of algorithms and architectures for H.264 sub-pixel motion estimation(World Scientific, 2012-05) Fatemi, Mohammad Reza Hosseiny; Ateş, Hasan Fehmi; Salleh, Rosli BinThis paper reviews recent state-of-the-art H. 264 sub-pixel motion estimation (SME) algorithms and architectures. First, H.264 SME is analyzed and the impact of its functionalities on coding performance is investigated. Then, design space of SME algorithms is explored representing design problems, approaches, and recent advanced algorithms. Besides, design challenges and strategies of SME hardware architectures are discussed and promising architectures are surveyed. Further perspectives and future prospects are also presented to highlight emerging trends and outlook of SME designs.Yayın A design technique of 50 Ω terminated bandpass matching network and its implementation to a Y-shaped monopole antenna matching(Springer, 2016-12) Aydın, Çağatay; Atilla, Doğu Çağdaş; Köprü, Ramazan; Kılınç, Sedat; Karakuş, Cahit; Yarman, Bekir Sıddık BinboğaIn this paper, a 50 Ω terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 Ω by numerical package. Hence, a transformer is also required for 50 Ω termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.Yayın Extremum seeking control of uncertain systems(Işık University Press, 2017) Dinçmen, ErkinExtremum seeking is used in control problems where the reference trajectory or reference set point of the system is not known but it is searched in real time in order to maximize or minimize a performance function representing the optimal behaviour of the system. In this paper, extremum seeking algorithm is applied to the systems with parametric uncertainties.Yayın Low pass filter design with improved stop-band suppression and synthesis with transformer-free ladders(John Wiley and Sons Inc, 2021-09) Yıldız, Serkan; Aksen, Ahmet; Kılınç, Sedat; Yarman, Bekir Sıddık BinboğaA new method to design transformer-free low pass (LP) ladder network with improved stop-band suppression performance is introduced. The parametric representation of back-end impedance of LP filter network is established with minimum impedance part and a Foster reactance part. The constructed impedance function is optimized by using real frequency technique. It has been shown that the proposed method provides LP filters which have superior stop-band suppression in comparison with classical transfer function-based filters with same complexity. The synthesis of the LP filter is obtained with the proposed element extraction procedure and resulted with fully realizable network elements in ladder form. An LP filter design and application by employing the proposed technique is provided. The measurement results of the prototyped filter are presented.Yayın Fast algorithm analysis and bit-serial architecture design for sub-pixel motion estimation in H.264(World Scientific Publishing Company, 2010-12) Fatemi, Mohammad Reza Hosseiny; Ateş, Hasan Fehmi; Salleh, Rosli BinThe sub-pixel motion estimation (SME), together with the interpolation of reference frames, is a computationally extensive part of the H.264 encoder that increases the memory requirement 16-times for each reference frame. Due to the huge computational complexity and memory requirement of the H.264 SME, its hardware architecture design is an important issue especially in high resolution or low power applications. To solve the above difficulties, we propose several optimization techniques in both algorithm and architecture levels. In the algorithm level, we propose a parabolic based algorithm for SME with quarter-pixel accuracy which reduces the computational budget by 94.35% and the memory access requirement by 98.5% in comparison to the standard interpolate and search method. In addition, a fast version of the proposed algorithm is presented that reduces the computational budget 46.28% further while maintaining the video quality. In the architecture level, we propose a novel bit-serial architecture for our algorithm. Due to advantages of the bit-serial architecture, it has a low gate count, high speed operation frequency, low density interconnection, and a reduced number of I/O pins. Also, several optimization techniques including the sum of absolute differences truncation, source sharing exploiting and power saving techniques are applied to the proposed architecture which reduce power consumption and area. Our design can save between 57.71-90.01% of area cost and improves the macroblock (MB) processing speed between 1.7-8.44 times when compared to previous designs. Implementation results show that our design can support real time HD1080 format with 20.3 k gate counts at the operation frequency of 144.9 MHz.Yayın Dual band stop filter design via frequency transformation and synthesis with lumped resonators(Institution of Engineering and Technology, 2020-05-01) Yıldız, Serkan; Aksen, Ahmet; Kılınç, Sedat; Yarman, Bekir Sıddık BinboğaThis study presents a new compact design technique for dual band stop (DBS) filter. Analytical formulation of DBS frequency transformation/mapping is derived in terms of parametric representation of band characteristic of DBS filter. The analytical derivation of the transformation function is based on sequential application of classical low pass to band stop (LP to BS) and low pass to band pass (LP to BP) transformations. Assigned band characteristic of DBS filter can be achieved by applying the proposed transformation function on an LP prototype network. The explicit network topologies for DBS reactance mapping are presented. Several numerical examples are provided to validate the proposed mapping function. An implantation example of DBS filter for GSM900 and GSM1800/UMTS bands is given. Mixed element realisation of the designed filter and measurement results of the design are presented.
