Optimization Algorithms For The Multiple Constant Multiplications Problem

(Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009(PhD) -- İstanbul Technical University, Institute of Science and Technology, 2009Bu tezde, birden fazla katsayının çarpımı (MCM) problemi, bir başka deyişle, bir değişkenin birden fazla katsayı ile çarpımının minimum sayıda toplama/çıkarma işlemi kullanılarak gerçeklenmesi için tasarlanmış kesin ve yaklaşık algoritmalar sunulmaktadır. Bir kesin alt ifade eliminasyonu (CSE) algoritmasının tasarımında, MCM problemini bir 0-1 tamsayı lineer programlama problemi olarak modelleyen daha önceden önerilmiş bir algoritma temel alınmıştır. Kesin CSE algoritması içinde, alan ve gecikme ölçütlerini ele alabilmek için yeni bir kesin model önerilmektedir. Kesin CSE algoritması tarafından taranacak arama uzayını küçültmek için problem indirgeme ve model basitleştirme teknikleri sunulmaktadır. Bu tekniklerin kullanımının kesin CSE algoritmasının daha büyük örnekler üzerinde uygulanmasına olanak sağladığı gösterilmektedir. Ayrıca, bu teknikler ile donatılmış kesin CSE algoritması, katsayıları genel sayı gösteriminde ele alacak ve kesin CSE algoritmasından daha iyi sonuçlar elde edecek şekilde genişletilmektedir. Bunların yanında, gerçek boyutlu örnekler üzerinde uygulanabilen bir kesin graf tabanlı algoritma sunulmaktadır. Bu kesin algoritmalara ek olarak, minimum sonuçlara oldukça yakın çözümler bulabilen ve kesin algoritmaların ele almakta zorlandığı örneklere uygulanabilen yaklaşık CSE ve graf tabanlı algoritmalar verilmektedir. Bu tezde önerilen kesin ve yaklaşık algoritmaların daha önceden önerilmiş sezgisel yöntemlerden daha iyi sonuçlar verdiği gösterilmektedir. Bunların yanısıra, bu tezde, kesin CSE algoritması gecikme kısıtı altında alanın minimize edilmesi, kapı seviyesinde alanın minimize edilmesi ve yüksek hızlı sayısal sonlu impuls cevaplı filtrelerin tasarımında alanın optimize edilmesi problemlerine uygulanmaktadır.In this thesis, exact and approximate algorithms designed for the multiple constant multiplications (MCM) problem, i.e., the implementation of the multiplication of a variable with multiple constants using minimum number of addition/subtraction operations, are introduced. In the design of an exact common subexpression elimination (CSE) algorithm, we relied on the previously proposed algorithm that models the MCM problem as a 0-1 integer linear programming problem. To handle the area and delay parameters in the exact CSE algorithm, a new exact model is proposed. To reduce the search space to be explored by the exact algorithm, problem reduction and model simplification techniques are introduced. It is shown that the use of these techniques enable the exact CSE algorithm to be applied on larger size instances. Also, the exact CSE algorithm equipped with these techniques is extended to handle the constants under general number representation yielding better solutions than those of the exact CSE algorithm. Besides, an exact graph-based algorithm that can be applied on real size instances is introduced. In addition to the exact algorithms, approximate CSE and graph-based algorithms that find similar results with the minimum solutions and can be applied on instances that the exact algorithms cannot deal with are presented. It is shown that the exact and approximate algorithms proposed in this thesis give better solutions than those of the previously proposed heuristic algorithms. Furthermore, in this thesis, the exact CSE algorithm is applied on the minimization of area under a delay constraint, the minimization of area at gate-level, and the optimization of area in high-speed digital finite impulse response filters synthesis problems.DoktoraPh

KRATT: QBF-Assisted Removal and Structural Analysis Attack Against Logic Locking

This paper introduces KRATT, a removal and structural analysis attack against state-of-the-art logic locking techniques, such as single and double flip locking techniques (SFLTs and DFLTs). KRATT utilizes powerful quantified Boolean formulas (QBFs), which have not found widespread use in hardware security, to find the secret key of SFLTs for the first time. It can handle locked circuits under both oracle-less (OL) and oracle-guided (OG) threat models. It modifies the locked circuit and uses a prominent OL attack to make a strong guess under the OL threat model. It uses a structural analysis technique to identify promising protected input patterns and explores them using the oracle under the OG model. Experimental results on ISCAS'85, ITC'99, and HeLLO: CTF'22 benchmarks show that KRATT can break SFLTs using a QBF formulation in less than a minute, can decipher a large number of key inputs of SFLTs and DFLTs with high accuracy under the OL threat model, and can easily find the secret key of DFLTs under the OG threat model. It is shown that KRATT outperforms publicly available OL and OG attacks in terms of solution quality and run-time

A comparison of biosurfactant production between clinical and environmental exophiala isolates

Black Yeast in the genus Exophiala are able to grow in hydrocarbon-contaminated environments and are pathogenic in immunosuppressed hosts. The biosurfactant produced by Exophiala species May be associated with strain pathogenicity by changing the hydrophobicity. The aim of this study was to prove the hypothesis that biosurfactant production in Exophilia strains isolated from clinical samples is lower than the strains isolates from toxic (dishwasher and railway sleepers) environments. A total of 122 Exophiala isolates 108 environmental (isolated from 82 dishwashers and 36 railway sleepers) and 14 clinical isolates confirmed by molecular tests were included in the study. Biosurfactant activity was tested by the drop collapse method, in which the surface of a microtiter plate well was evaluated for the presence of a biosurfactant, and by the oil spreading technique on crude oil. An open source analyses program, ImageJ ® , was used for crude oil spreading technique data. A clear surface zone that differs more than two standard deviations from the mean size was accepted as a positive result. Among the 122 Exophiala species, 11 (9.0%) and 10 (8.2%) strains showed biosurfactant activity by the drop collapse test and oil spreading method, respectively. An acceptable relation was found between the drop collapse test and oil spreading method (Cohen κ coefficient= 0.30). Despite the presence of isolates showing biosurfactant activity, no statistically significant difference was detected between Exophiala strains (p= 0.72). The biosurfactant levels of environmental isolates were higher than the isolates obtained from the patients (p= 0.03). The highest biosurfactant level was observed in one Exophiala phaeomuriformis strain isolated from a dishwasher. There was no difference between the biosurfactant levels of the dishwasher and railway sleeper isolates (p= 0.66). Biosurfactant production May be a more important determinant of virulence in Exophiala species than expected. In this study, biosurfactant activity was higher in environmental isolates compared to the clinical isolates. Consensus of multiple biosurfactant screening protocols May clarify why environmental Exophiala species are less virulent. Further studies should evaluate biosurfactant activity in additional clinical Exophiala isolates. The biosurfactant activity of more Exophiala isolates obtained from patients should be investigated with further planned studies. © 2018 Ankara Microbiology Society. All rights reserved

A Satisfiability-Based Approximate Algorithm for Logic Synthesis Using Switching Lattices

In recent years the realization of a logic function on two-dimensional arrays of four-terminal switches, called switching lattices, has attracted considerable interest. Exact and approximate methods have been proposed for the problem of synthesizing Boolean functions on switching lattices with minimum size, called lattice synthesis (LS) problem. However, the exact method can only handle relatively small instances and the approximate methods may find solutions that are far from the optimum. This paper introduces an approximate algorithm, called JANUS, that formalizes the problem of realizing a logic function on a given lattice, called lattice mapping (LM) problem, as a satisfiability problem and explores the search space of the LS problem in a dichotomic search manner, solving LM problems for possible lattice candidates. This paper also presents three methods to improve the initial upper bound and an efficient way to realize multiple logic functions on a single lattice. Experimental results show that JANUS can find solutions very close to the minimum in a reasonable time and obtain better results than the existing approximate methods. The solutions of JANUS can also be better than those of the exact method, which cannot be determined to be optimal due to the given time limit, where the maximum gain on the number of switches reaches up to 25%.This work is part of a project that has received funding from the European Union’s H2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 691178, and supported by the TUBITAK-Career project #113E76

Area optimization algorithms in high-speed digital FIR filter synthesis

Son on yıl içinde, birden fazla katsayının çarpımı (MCM) problemi, bir başka deyişle, bir değişkenin birden fazla katsayı ile çarpımının en az sayıda toplama/çıkarma işlemleri kullanılarak tasarımı, için etkili algoritmalar önerilmiştir. Bu algoritmalarda, toplama/çıkarma işlemi iki girişli bir işlem olarak kabul edilmekte ve genellikle, hesaplama süresi fazla olan elde ötelemeli toplayıcılar ile gerçeklenmektedir. Bunun yanında, elde korumalı toplayıcılar (CSA) çok girişli toplama işlemlerinin yüksek hızlı tasarımında sıklıkla kullanılmaktadır. Yine de, CSA blok sayısının optimizasyonu için önerilen algoritmalar sezgisellerdir ve minimum sonucu garanti edemezler. Bu makalede, MCM işlemi için gereken minimum sayıdaki CSA bloklarını bulan bir kesin ortak alt ifade eliminasyonu (CSE) algoritması önerilmektedir. Önerilen kesin yöntem gerçek boyutlu örnekler üzerinde uygulanabilse de, MCM probleminin bir NP-bütün problem olmasından dolayı, doğal olarak, kesin algoritmanın ele alamayacağı örnekler mevcuttur. Bu yüzden, bu makalede, büyük boyutlu örnekleri ele alabilen bir yaklaşık CSE yöntemi de önerilmekedir. CSE algoritmaları ile elde edilen sonuçlar katsayıların gerçeklenmesi için kullanılan sayı gösterimlerine bağlı olduğundan bu makalede, ayrıca, katsayıların genel sayı gösterimindeki ifadelerini ele alabilen bir yaklaşık yöntem de sunulmaktadır. Önerilen algoritmalar, rastgele üretilmiş örnekler ve FIR filtreleri üzerinde test edilmiş ve daha önceden önerilmiş CSE ve graf tabanlı sezgisel yöntemler ile karşılaştırılmıştır. Deneysel sonuçlardan kesin CSE algoritmanın sezgisel CSE yönteme göre oldukça iyi sonuçlar elde ettiği ve genel sayı gösterimi altında yaklaşık algoritmanın graf tabanlı sezgisel yöntemle rekabet edebilecek düzeyde ve daha iyi sonuçlar bulduğu gözlenmektedir.  Anahtar Kelimeler: Birden fazla katsayının çarpımı problemi, ortak alt ifade eliminasyonu, elde ötelemeli toplama, elde korumalı toplama, 0-1 tamsayı lineer programlama.Digital Finite Impulse Response (FIR) filters are frequently used in Digital Signal Processing (DSP) by virtue of stability and easy implementation. The problem of designing the multiplier block of a digital FIR filter has received a significant amount of attention during the last decade, as the filters require a large number of multiplications, leading to excessive area, delay, and power consumption even if implemented in a full custom integrated circuit. Previous works have focused on the design of filters with minimum area by replacing the multiplication operations with constant coefficients by addition, subtraction, and shifting operations. Since shifts can be implemented with only wires in hardware, the design problem can be defined as the minimization of the number of addition/subtraction operations to implement the coefficient multiplications. This problem is generally known as the MCM problem. In the last decade, many efficient algorithms have been proposed for the MCM problem. These algorithms can be categorized in two classes: Common Subexpression Elimination (CSE) and graph-based algorithms. While the CSE algorithms basically find the common non-zero digit patterns on the representations of the constants, the graph-based algorithms are not restricted to a particular number representation and synthesize the constants iteratively by build-ing a graph.However, in the algorithms proposed for the MCM problem, an addition/subtraction operation is assumed to be a two-input operation that is generally implemented using a Ripple Carry Adder (RCA) block yielding great latency in the implementation of MCM. In high-speed applications, particularly in DSP systems, Carry-Save Adder (CSA) blocks are preferred to RCA blocks taking into account the increase in area.Despite the large number of algorithms designed for the minimization of addition/subtraction operations based on RCAs, there are only a few algorithms proposed for the optimization of the number of CSA blocks. Although these algorithms give good results, they are based on heuristics, i.e., provide no indication on how far from the minimum their solutions are. To the best of our knowledge, there is no exact algorithm proposed for the optimization of the number of CSA blocks in MCM.In this paper, an exact CSE algorithm designed for the minimization of the number of CSA blocks is introduced. In the exact CSE algorithm, initially, all possible implementations of filter coefficients and partial terms using CSAs are found when filter coefficients are defined under a number representation, and a combinational network that represents the implementations of constants is constructed. Then, the minimization of the number of CSA blocks problem is defined as a 0-1 Integer Linear Programming (ILP) problem with a cost function to be minimized and constraints to be satisfied. Finally, a generic 0-1 ILP solver is used to obtain the minimum solution. Due to the NP-completeness of the MCM problem, naturally, there are instances that the exact algorithm cannot handle. Hence, in this paper, we also introduce an approximate CSE algorithm based on the exact CSE algorithm that considers limited implementations of the coefficients reducing the size of the search space to be explored significantly. It is also shown that the approximate CSE algorithm obtains similar results with the exact CSE algorithm. Since the solutions obtained by the proposed CSE algorithms depend on the number representation, in the approximate algorithm, the number of possible implementations of filter coefficients is increased using a general number representation allowing the approximate algorithm to be more effective in area optimization. It is shown that the approximate algorithm under general number representation obtains more promising results than the approximate CSE algorithm. In this paper, the results of the proposed exact and approximate algorithms on a comprehensive set of instances including randomly generated and FIR filter instances are presented. It is shown that the proposed algorithms can be applied on real size instances. Also, the results of the exact and approximate algorithms are compared with those of the previously proposed CSE and graph-based heuristics. As observed from the experimental results, the exact and approximate CSE algorithms find significantly better solutions than the CSE heuristic and the approximate algorithm under general number representation obtains competitive and better results than the graph-based heuristic. Keywords: Multiple constant multiplications, common subexpression elimination, ripple carry adders, carry save adders, 0-1 integer linear programming

Evaluation of dissociative life of male athletes in some disability sportive branches

This research focused on evaluation of dissociative lives of male disabled athletes who played in teams of amputee football league and regional wheelchair basketball league. In this research; general survey method, one of the descriptive research methods, was used. As data collection tools; “Personal Information Form”, “Household Income Form” and “The Dissociation Scale Questioner” were used. A total of 92 male disabled participants (55 amputee football players and 37 wheelchair basketball players) were included in the study.There were no significant statistical differences between participants’ dissociation levels and age, educational status, marital status, whether or not being a national player and employment status. However; there was statistically significant difference in terms of use of prostheses-use, sportive branch, household income and time of disability.It may be argued that acquired traumatic events that occur after birth have stronger traumatic life levels/effects compared to congenital traumatic events that occur before or during birt

Attitudes of Pregnant Women toward the COVID-19 Vaccine

Objective: It was carried out to determine the attitudes of pregnant women toward the Covid-19 vaccine and related factors. Methods: The correlational and descriptive study was conducted with 356 pregnant women. In the study, data were collected using an introductory questionnaire, "Attitudes towards Covid-19 Vaccine Scale", "Vaccination Hesitancy in Pandemics Scale", and "Covid-19 Vaccine Literacy Scale". Research data were analyzed with SPSS 25 package program. One-way ANOVA and Student-t test were used to determine the difference between the descriptive characteristics of the pregnant women participating in the study and the total and sub-dimension mean scores of the Attitude Scale towards the Covid-19 Vaccine. Pearson correlation analysis was used to determine the relationship between the Vaccine Hesitancy Scale in Pandemics, the Covid-19 Vaccine Literacy Scale, and the Attitudes Towards Covid-19 Vaccine Scale. Linear regression analysis was used to determine the factors affecting the Attitudes of Pregnants towards the Covid-19 Vaccine. Results: It was concluded that 37.4% of the pregnant women did not have any Covid-19 vaccine, 62.6% had the Covid-19 vaccine before pregnancy, and 22.5% had the vaccine during pregnancy. In pregnant women, those who have hesitations about the vaccine in cases such as working, increase in education level, fear of contracting Covid-19 before birth, having pre-pregnancy Covid-19 vaccine, thinking that pregnant women may have Covid-19 vaccine, getting Covid-19 vaccine during pregnancy, etc. increase their attitudes towards vaccination. Conclusion: Consider to change the conclusion: It was found that quite a few pregnant women received the Covid-19 vaccine during their pregnancy. Pregnant women's vaccination hesitancy influences their attitudes toward Covid-19

Efficacy of Trigger Point Injections in Patients with Lumbar Disc Hernia without Indication for Surgery

Study DesignProspective comparative study.PurposeTo investigate the efficacy of gluteal trigger point (TP) injections with prilocaine in patients with lumbosacral radiculopathy complaining of gluteal pain.Overview of LiteratureTP injections can be performed using several anesthetic agents, primarily lidocaine and prilocaine. While several studies have used lidocaine, few have used prilocaine.MethodsA total of 65 patients who presented at the polyclinic with complaints of lower back pain with lumbar disc herniation (based on physical examination and magnetic resonance imaging) and TPs in the gluteal region were included in this prospective comparative study. Group 1 comprised 30 patients who were given TP injections, a home exercise program, and oral medications, and group 2 comprised 35 patients who were only treated with a home exercise program and oral medications. The patients' demographic data, Oswestry Disability Index (ODI) scores, and Visual Analog Scale (VAS) scores were recorded, and these data were evaluated at 1- and 3-month follow-ups.ResultsThe ODI and VAS scores of both groups significantly decreased initially and at the follow-up examinations, but the decreases were more marked in group 1.ConclusionsWe obtained better results with TP injections than only a home exercise program and oral medications in patients with radiculopathy and TPs in the gluteal region

Audiological Results of Total Ossicular Replacement Prosthesis with Cartilage Shoe Technique

Objective:The aim of this study was to investigate functional results of total ossicular replacement prosthesis (TORP) shaft stabilization with a cartilage shoe in chronic otitis media patients with cholesteatoma who had undergone canal wall down tympanomastoidectomy (CWDT). In addition, it was determined whether the presence of granular and edematous mucosa in middle ear altered functional outcomes.Methods: Sixty patients, who had undergone CWDT with the use of TORP for the reconstruction of ossicular chain, were divided into two groups. Patients with cartilage shoe were classified as Group 1 (n=30) and those without the shoe were classified as Group 2 (n=30). Patients in both groups were classified into “A” and “B” subgroups according to the middle ear risk index (MERI). Air conduction (AC) and bone conduction thresholds were evaluated preoperatively and postoperatively.Results: There was no statistically significant change between preoperative AC thresholds of the groups and subgroups (p>0.05). There were statistically significant differences regarding AC thresholds and air– bone gap (ABG) values between Groups 1 and 2 at the postoperative 12th month (p<0.05). Postoperative AC thresholds and ABG values of Group 1B patients with a high MERI score were statistically significant at all frequencies than those of Group 2B patients (p<0.05). When ABG values were compared, it was observed that functional results were better in Group 1B, but a statistically significant difference was observed only at 2000 Hz (p<0.01).Conclusion: The cartilage shoe method for titanium TORP stabilization that is used for ossicular reconstruction during CWDT has been found to have a beneficial effect on auditory outcomes. Cartilage shoe application increases positive effects on hearing outcomes, particularly if the middle ear mucosa is granular and edematous