Mühendislik Fakültesi / Faculty of Engineering
Permanent URI for this collectionhttps://hdl.handle.net/11727/1401
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Item Goodness-of-fit and Randomness Tests for the Sun's Emissions True Random Number Generator(2014) Tanyer, Suleyman Gokhun; Atalay, Kumru Didem; Inam, Sitki Cagdas; 0000-0003-0820-9186; I-5023-2013; JHU-3888-2023Random number generators ( RNGs) are one of the key tools necessary for statistical analysis and optimization methods such as Monte Carlo, particle swarm optimization ( PSO) and the genetic algorithm. Various pseudo and true RNGs are available today, and they provide sufficient randomness. Unfortunately, they generate data that do not always represent the required distribution accurately, especially when the data length is small. This could possibly threaten the 'repeatability' of an academic study. A novel true RNG ( TRNG) using the method of uniform sampling ( MUS) is recently proposed. In this work, the Sun's RF emissions MUS-TRNG is comparatively tested with well known pseudo and true RNGs. It is observed that both randomness and very high goodness-of-fit qualities are possible.Item True Random Number Generation of Very High Goodness-of-fit and Randomness Qualities(2014) Tanyer, Suleyman Gokhun; I-5023-2013The statistical nature of numerous problems in mathematics, physics and engineering have led to the development of methods for generating random data for a given distribution. Ancient methods include; dice, coin flipping and shuffling of cards. Today, various pseudo, quasi and true random generators ( RNGs) are being proposed for their improved properties. In this work, test metrics for goodness-of-fit and randomness are reviewed. The method of uniform sampling ( MUS) is modified for improving the randomness without harming the goodness-of-fit qualities. The test results illustrate that very high goodness-of-fit can be obtained even when the number of observed samples is as small as 10.Item Efficient Recognition of Human Emotional States from Audio Signals(2014) Erdem, Ernur Sonat; Sert, Mustafa; https://orcid.org/0000-0002-7056-4245; AAB-8673-2019Automatic recognition of human emotional states is an important task for efficient human-machine communication. Most of existing works focus on the recognition of emotional states using audio signals alone, visual signals alone, or both. Here we propose empirical methods for feature extraction and classifier optimization that consider the temporal aspects of audio signals and introduce our framework to efficiently recognize human emotional states from audio signals. The framework is based on the prediction of input audio clips that are described using representative low-level features. In the experiments, seven (7) discrete emotional states (anger, fear, boredom, disgust, happiness, sadness, and neutral) from EmoDB dataset, are recognized and tested based on nineteen (19) audio features (15 standalone, 4 joint) by using the Support Vector Machine (SVM) classifier. Extensive experiments have been conducted to demonstrate the effect of feature extraction and classifier optimization methods to the recognition accuracy of the emotional states. Our experiments show that, feature extraction and classifier optimization procedures lead to significant improvement of over 11% in emotion recognition. As a result, the overall recognition accuracy achieved for seven emotions in the EmoDB dataset is 83.33% compared to the baseline accuracy of 72.22%.Item A New Approach to Fuzzy Initial Value Problem(2014) Gasilov, N. A.; Fatullayev, A. G.; Amrahov, S. E.; Khastan, A.; https://orcid.org/0000-0002-9955-8439; AEN-1756-2022In this paper, we consider a high-order linear differential equation with fuzzy initial values. We present solution as a fuzzy set of real functions such that each real function satisfies the initial value problem by some membership degree. Also we propose a method based on properties of linear transformations to find the fuzzy solution. We find out the solution determined by our method coincides with one of the solutions obtained by the extension principle method. Some examples are presented to illustrate applicability of the proposed method.Item Computational Prediction of MicroRNA Function and Activity(2014) Ogul, Hasan; 24272442Inferring microRNA (miRNA) functions and activities has been extremely important to understand their system-level roles and the mechanisms behind the cellular behaviors of their target genes. This chapter first details methodologies necessary for prediction of function and activity. It then introduces the computational methods available for investigation of sequence and experimental data and for analysis of the information flow mediated through miRNAs.Item Functional Copolymer/Organo-MMT Nanoarchitectures. XXII. Fabrication and Characterization of Antifungal and Antibacterial Poly (Vinyl Alcohol-co-Vinyl Acetate/ODA-MMT/AgNPs Nanofibers and Nanocoatings by e-Spinning and c-Spinning Methods(2015) Rzayev, Zakir M. O.; Erdonmez, Demet; Erkan, Kubra; Simsek, Murat; Bunyatova, Ulviye; 0000-0002-2904-3587Nanofibrous films and coatings were fabricated by electrospinning and centrifugal spinning of aqueous solutions of poly(vinyl alcohol-co-vinyl acetate)/octadecyl amine-montmorillonite layered silicate nanocomposites with/without in situ generated silver nanoparticles (AgNPs). Characterization of nanofibers were realized by FTIR, XRD, SEM, and thermal analysis methods. It was found that AgNPs significantly accelerated phase separation process providing fine distribution of nanofibers. Antifungal and antimicrobial activities of nanocomposites investigated by using Candida Spp fungals, G-positive and G-negative microorganisms strongly depended on chemical/physical structural factors, and loading silver species. Observed effective properties of nanomaterials can be employed for many applications (e.g., air filtration, food packaging, biomedical).Item The Effect of Organizational Culture on Implementing and Sustaining Lean Processes(2015) Pakdil, Fatma; Leonard, Karen Moustafa; 0000-0002-6299-6427; H-8189-2013Purpose - Lean systems thinking was widely studied using relevant variables, but there is a dearth of published theoretical or empirical evidence about the cultural aspects of lean processes. The lack of conceptual development is one of the motivations for this study. Do organizational cultural variations correlate with the success and effectiveness of lean processes? What organizational infrastructures are required for effective lean implementation and continuation? The paper aims to discuss these issues. Design/methodology/approach - Examining literature in the area of lean production and lean management, the authors sought current literature at the intersection of organizational culture and lean processes, particularly implementation and sustainability, but found little relating to the topic. Therefore, using the Competing Values Framework taxonomy, the authors examine this intersection, relying on related research in the areas. Findings - In this paper, a brief discussion of lean processes in relation to organizational culture leads to propositions that identify the various cultural dimensions and their purported effect on lean implementation and sustainability. A model of this interaction is developed. Those quadrants of the Competing Values Framework that might be useful in developing research directions for the future are identified. Research limitations/implications - Future research directions include the measurement of organizational culture in firms that have implemented lean processes. This would be a step toward looking at the effect that the different quadrants in the Competing Values Framework have on various elements of lean efforts. This would take a significant amount of work, because the manufacturing industry, the leader in implementing and sustaining lean processes, may have institutionalized particular organizational cultures. It would be an interesting step forward in the understanding of how lean processes are operationalized across different firms and industries. However, there are multiple ways to examine culture; the authors believe this method allows the capture of the entire spectrum. Practical implications - Knowing which dimensions influence lean effectiveness and the way that they wield that influence allows managers to develop the firm's organizational culture to one that will support implementing and sustaining lean efforts. The challenge to implement and sustain lean processes lies in the need to identify the organizational culture infrastructure that will allow this system that was first used by Japanese firms to operate well in other organizational contexts. The values and norms that underlie lean processes may create conflict with the culture that already exists within the organization; such divergence retards adoption and performance. Originality/value - There is a lack of research at the critical intersection of organizational culture and lean implementation/sustainability. Culture is key to making the changes required of lean implementation and in sustaining the drive toward lean production and management. The paper begins to fill that gap.Item A Decision Support System for Selection of Net-Shape Primary Manufacturing Processes(2014) Yurdakul, Mustafa; Arslan, Emre; Ic, Yusuf Tansel; Turkbas, O. Selim; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022Developments in the capabilities of the manufacturing processes increased the number of processes that can produce a part within the requirements determined by its design and market research. The increased number of processes and unfamiliarity of manufacturing engineers to many new manufacturing processes forces the researchers to develop systematic process selection tools instead of depending on the accumulated human expertise only. In this paper, a net-shape primary manufacturing process selection decision support system (DSS), which is named PROSEL (PROcess SELection), is developed. The developed selection programme eliminates the unsuitable processes step by step by checking a part's material, annual production quantity, specified shape, thickness and presents the most economical process as the most appropriate net-shape primary process after a final cost analysis. The developed DSS is written in Visual Studio and tested with a great deal of real-life examples. It can be concluded from the tests that the programme provides the same or better primary manufacturing process selection decisions than the practical usage, and it is a very useful support tool for net-shape primary process selections.Item A TOPSIS Based Design of Experiment Approach to Assess Company Ranking(2014) Ic, Yusuf Tansel; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022Company ranking is a complex process in which multiple financial ratios are required to be considered simultaneously. Furthermore, the selection process of an appropriate credit applicant company has become more complex as the experts in the financial organizations have to assess a wide range of alternatives based on a set of conflicting financial criteria. This paper studies the application of a new approach, i.e., Design of Experiment and TOPSIS method (DoE-TOPSIS) together to make company raking as frequently encountered in the real-time financial environment. The developed model is tested by case studies and satisfactory results are obtained. In the case studies, the results obtained by using the combined DoE-TOPSIS method are almost corroborated by those derived from conventional multi attribute decision making (MADM) methods which prove the applicability, potentiality, simplicity and flexibility of this method in making company ranking. (C) 2013 Elsevier Inc. All rights reserved.Item Computer Based Eye-Writing System by Using Eog(2015) Ulkutas, Hesna Ozbek; Yildiz, Metin; 0000-0002-2554-6953; JJF-5070-2023The aim of this study is to suggest a faster method that would also have better accuracy rate in coding eye movements into characters compared to previously developed by EOG visual writing techniques and to develop a system of computer-based applications that would implement this new method. To this end, several experiments were utilized in order to determine the performance of the observed coding method we propose, with reference to these experiments results; a new method encoding 29 letters and 3 commands ( spaces, erase, read) by utilizing only 4 directions with two different angles and four different waiting period is proposed. For implementing proposed new technique, a computer based EOG measurement and inference system is developed. The results of trials with this newly developed system indicate that while the accuracy rate of coding into right characters in the first trial of a text comprised of 180 letters is 92.5%, this accuracy rate of the coding reaches to 100% starting from the fourth trial of the technique. Average writing speed of 16.8 words per minute that is measured with this method is the highest rate that has been achieved among EOG-based systems.