Short-Term Flood Control and Long-Term Energy Maximization in Multi-reservoir Systems Using Improved Particle Swarm Optimization

Water Resources Management - In this study, a model is developed for short-term flood control of a complex multi-reservoir system located on one of the largest basins in Turkey. The managing body...     

An experimental study on grinding of Zr-based bulk metallic glass

There are limited studies in the literature about machinability of bulk metallic glass(BMG).As a novel and promising structural material,BMG material machining characteristics need to be verified before its utilization.In this paper,the effects of cutting speed,feed rate,depth of cut,abrasive particle size/type on the BMG grinding in dry conditions were experimentally investigated.The experimental evaluations were carried out using cubic boron nitride(CBN) and Al_2O_3 cup wheel grinding tools.The parameters were evaluated along with the results of cutting force,temperature and surface roughness measurements,X-ray,scanning electron microscope(SEM)and surface roughness analyse.The results demonstrated that the grinding forces reduced with the increasing cutting speed as specific grinding energy increased.The effect of feed rate was opposite to the cutting speed effect,and increasing feed rate caused higher grinding forces and substantially lower specific energy.Some voids like cracks parallel to the grinding direction were observed at the edge of the grinding tracks.The present investigations on ground surface and grinding chips morphologies showed that material removal and surface formation of the BMG were mainly due to the ductile chip formation and ploughing as well as brittle fracture of some particles from the edge of the tracks.The roughness values obtained with the CBN wheels were found to be acceptable for the grinding operation of the structural materials and were in the range of 0.34-0.58 μm.This study also demonstrates that conventional Al_2O_3 wheel is not suitable for grinding of the BMG in dry conditions.     

Ibuprofen release from porous hydroxyapatite tablets

The present study investigated drug release profiles from porous hydroxyapatite [Ca₅(PO₄)₃OH, HAP] tablets. HAP tablets prepared synthetically and porous structure was generated via microemulsion after sintering at 700 °C. The influence of tablet's microemulsion concentration on drug release profiles from sintered porous tablets was investigated by using ibuprofen (C₁₃H₁₈O₂) as model drug.A numerical approach based on Fick's second diffusion law was used to investigate drug release kinetics from porous HAP tablets. Via this equation, diffusion coefficients were calculated for each tablet and compared. Drug release from the tablets was influenced by the porosity and tortuosity of the porous network. The drug release from porous HAP tablets was increased by microemulsion concentration. It is possible to obtain HAP based drug delivery system which has different drug release behavior by controlling microemulsion concentration in tablets before sintering.     

Impact of reliability on warranty: A study of application in a large size company of electronics industry

This paper presents product reliability on component basis and investigates the possible effects on warranty which constitutes a non-technical issue. Product reliability is a key factor, which is used in considering the warranty period. It plays a significant role that a mistake in warranty forecasting could cost a lot for companies. The objective is to empirically examine the nature of general reliability of manufactured goods and conduct a case study in an electronics company. In this regard, reliability will be stated from the actual manufacturing point of view. A case study was applied in manufacturing industry. LCD TVs were undertaken to follow. To test reliability, a parametric Weibull model was used and hazard rates of products were estimated with linear regression method. For this research work, the lifetime data obtained by service departments, censored both left and right. Data were used in MINITAB14 to produce the reliability results of the LCDs to reveal the relationship between product reliability and product warranty in the consumer electronics industry. In this manner, this paper would help the company to decide whether it is favorable to extend the warranty period based on the failure findings.     

BilVideo: Design and Implementation of a Video Database Management System

With the advances in information technology, the amount of multimedia data captured, produced, and stored is increasing rapidly. As a consequence, multimedia content is widely used for many applications in today’s world, and hence, a need for organizing this data, and accessing it from repositories with vast amount of information has been a driving stimulus both commercially and academically. In compliance with this inevitable trend, first image and especially later video database management systems have attracted a great deal of attention, since traditional database systems are designed to deal with alphanumeric information only, thereby not being suitable for multimedia data.In this paper, a prototype video database management system, which we call BilVideo, is introduced. The system architecture of BilVideo is original in that it provides full support for spatio-temporal queries that contain any combination of spatial, temporal, object-appearance, external-predicate, trajectory-projection, and similarity-based object-trajectory conditions by a rule-based system built on a knowledge-base, while utilizing an object-relational database to respond to semantic (keyword, event/activity, and category-based), color, shape, and texture queries. The parts of BilVideo (Fact-Extractor, Video-Annotator, its Web-based visual query interface, and its SQL-like textual query language) are presented, as well. Moreover, our query processing strategy is also briefly explained.This work is partially supported by the Scientific and Research Council of Turkey (TÜBİTAK) under Project Code 199E025, Turkish State Planning Organization (DPT) under Grant No. 2004K120720, and European Union under Grant No. FP6-507752 (MUSCLE Network of Excellence Project).     

Effects of using a force feedback haptic augmented simulation on the attitudes of the gifted students towards studying chemical bonds in virtual reality environment

The aim of this study is to identify the effects of force feedback haptic applications developed in virtual reality environments (VREs), which is an important field of study in computer science and engineering, on gifted students’ attitudes towards chemistry education in learning process. A 3D 6 DOF (Degree of Freedom) haptik device (Phantom Omni?) has been used to develop the algorithm in this study. It can be used to transmit force and motion using a haptic device. Visual C++ was choosen as the software development environment. OpenGL? and Haptic Device Application Programming Interface have been used for rendering graphics. At the 3D image creation state Wrap 1200?, which is a kind of head-mounted display, has been chosen. The sample of this study consists of 52 students identified as gifted and are attending 6th and 7th grades at the Istanbul Science &; Art Center in Istanbul. The experimental group studied chemical bonds using an application developed by using a force feedback haptic device in VRE and the control group studied it by traditional teaching methods. The study reveals that there is a relation between using force feedback haptic applications which are developed in VREs and gifted students’ attitudes towards educational programs.     

Risk-sensitive filtering for jump Markov linear systems

In this paper, a risk-sensitive multiple-model filtering algorithm is derived using the reference probability methods. First, the approximation of the interacting multiple-model (IMM) algorithm is identified in the reference probability domain. Then, the same type of approximation is used to derive the finite-dimensional risk-sensitive filtering algorithm. The derived algorithm reduces to the IMM filter when the risk-sensitive parameter goes to zero and reduces to the risk-sensitive filter for linear Gauss-Markov systems when the number of models is unity. The algorithm performs better in a simulated uncertain parameter scenario than the IMM filter.     

A fuzzy analytic network process based approach to transportation-mode selection between Turkey and Germany: A case study

A case study examining the different modes for transportation of freight by a Turkish logistics-service provider company is presented herein. A number of conflicting qualitative and quantitative criteria exist for evaluating alternative modes of transport. Qualitative criteria are often accompanied by ambiguity and vagueness. To cope with ambiguity and vagueness problem, the fuzzy analytic network process (ANP) method has been used. A large number of detailed criteria that interact with each other have been evaluated and synthesized to obtain the most suitable transportation mode. This evaluation has been carried out by a group of decision makers coming from different management levels and functional areas in the sector of logistics and from the service company with intent to provide a more accurate and mutually acceptable solution. Furthermore, the model used here has been validated by comparing the results obtained with the current preferences of the company.     

An online sequential algorithm for the estimation of transition probabilities for jump Markov linear systems

This paper describes a new method to estimate the transition probabilities associated with a jump Markov linear system. The new algorithm uses stochastic approximation type recursions to minimize the Kullback-Leibler divergence between the likelihood function of the transition probabilities and the true likelihood function. Since the calculation of the likelihood function of the transition probabilities is impossible, an incomplete data paradigm, which has been previously applied to a similar problem for hidden Markov models, is used. The algorithm differs from the existing algorithms in that it assumes that the transition probabilities are deterministic quantities whereas the existing approaches consider them to be random variables with prior distributions.     

Biometric template selection and update: a case study in fingerprints

A biometric authentication system operates by acquiring biometric data from a user and comparing it against the template data stored in a database in order to identify a person or to verify a claimed identity. Most systems store multiple templates per user in order to account for variations observed in a person's biometric data. In this paper we propose two methods to perform automatic template selection where the goal is to select prototype fingerprint templates for a finger from a given set of fingerprint impressions. The first method, called DEND, employs a clustering strategy to choose a template set that best represents the intra-class variations, while the second method, called MDIST, selects templates that exhibit maximum similarity with the rest of the impressions. Matching results on a database of 50 different fingers, with 200 impressions per finger, indicate that a systematic template selection procedure as presented here results in better performance than random template selection. The proposed methods have also been utilized to perform automatic template update. Experimental results underscore the importance of these techniques.