Statistical analyses of discontinuity parameters of Gölbaši (Ankara) Andesites,Süpren (Eskišehir) marble,and Porsuk Dam (Eskišehir) peridotite in Turkey

In this study aperture, persistence and spacing of discontinuities measured from three different rock types are treated statistically to determine their frequency distributions. Andesites of Gölba?i-Ankara, the marble of Süpren-Eski?ehir and the peridotite of Porsuk Dam-Eski?ehir are selected as rock types for which scan line surveys have been carried out. Statistical analyses are aimed at evaluating the distribution parameters, histograms, moments around zero, and moments around the mean of each set of data. The parameters are then utilized for making comparisons between the theoretical and the observed frequency distributions by means of Chi-Square tests and the method of Cross Correlations. Results of the statistical analyses have shown that the frequency distributions may not be the same in all rock types. The degree of weathering affects the frequency distribution of discontinuity spacing even in the same rock.     

A multi-dimensional shooting algorithm for the two-facility location–allocation problem with dense demand

We develop an efficient allocation-based solution framework for a class of two-facility location–allocation problems with dense demand data. By formulating the problem as a multi-dimensional boundary value problem, we show that previous results for the discrete demand case can be extended to problems with highly dense demand data. Further, this approach can be generalized to non-convex allocation decisions. This formulation is illustrated for the Euclidean metric case by representing the affine bisector with two points. A specialized multi-dimensional shooting algorithm is presented and illustrated on an example. Comparisons with two alternative methods through a computational study confirm the efficiency of the proposed methodology.     

Soft computing technique for power control of Triga Mark-II reactor

In this study, a trajectory tracking fuzzy genetic controller for Istanbul Technical University Triga Mark-II nuclear research reactor design approach is given. Power output of reactor is controlled along the predefined trajectory by fuzzy logic controller. Designed zero order Sugeno type fuzzy logic controller membership boundary value and rule weights are found by genetic algorithm. Non-chattering control with smooth control surface is also achieved using constrained fitness functions. Simulation results shows that reactor power successfully tracks the given trajectory under various working conditions and reaches the desired power level within the determined period within small tracking error.     

Improvement of grinding performance and investigation of cutting parameters using a grinding mechanism with secondary rotational axis

“Grinding Mechanism having Advanced Secondary Rotational Axis” (GMASRA) is one of the newer plane surface grinding methods that have an uncommon abrasion mechanism. Unlike conventional methods, in GMASRA, there are two rotations of a wheel. The first rotation is the same as in conventional grinding methods, which is the circumferential rotation. The other rotation is the newly developed axial rotation, where the wheel rotates around itself perpendicular to its radial axis. In this study, the effects of certain cutting parameters on arithmetical mean deviation of the assessed profile (the R_a parameter) were investigated. Particularly, the effects of cutting parameters on R_a in the GMASRA grinding process were examined. The selected cutting parameters were the depth of cut, the number of axial revolutions of the wheel, and the stepover distance of the wheel. Five wheels with different properties were chosen. Additionally, GMASRA was modeled using the Taguchi orthogonal test design. In this orthogonal design, the depth of cut, the spindle speed, and the type of grinding wheel were chosen as the control factors. The effect of the specified control factors on the surface roughness was demonstrated using an analysis of variance (ANOVA) test. Results show that GMASRA produced better R_a values than the conventional method. R_a values were very close to each other in every part of the ground workpieces. According to the modeling results, the spindle speed had the highest effect on R_a, followed by the depth of cut and the type of grinding wheel. GMASRA is also very cost effective and can be adapted to most milling machines and CNC milling machines.     

The Sectoral Sweeper Scheme for Wireless Sensor Networks: Adaptive Antenna Array Based Sensor Node Management and Location Estimation

We introduce a novel sensor node management and location estimation method referred as sectoral sweeper (SS) scheme that uses an adaptive antenna array (AAA) at a central node in wireless sensor networks (WSNs). With the SS scheme, the central node can activate or deactivate the nodes in a desired region which is specified by beam direction and beam width of the transmit beam and also by minimum and maximum thresholds (R _min and R _max) for the received signal strength indicator (RSSI) of signals received by the nodes. In order to perform a specified task that is associated with a Task_id, two different beams are transmitted, which are task region beam and routing region beam to switch the nodes into active or routing modes. Since our scheme does not require any additional software or hardware for node management and location estimation in sensor nodes, the deficiencies of tiny sensors are effectively eliminated. The proposed scheme is shown to reduce the number of sensing nodes and the amount of data traffic in the network, thus leading to considerable savings in energy consumption and prolonged sensor lifetime. Ayhan Erdogan graduated from Turkish Naval Academy, Istanbul, in 1992. He received the MSdegree from the Computer Engineering, Naval Sciences and Engineering Institute, Turkish Naval Academy, Istanbul, in 2003. He attended to a one year training on Automatic Data Processing (ADP) Officer in Middle East Technical University, Turkey, in 1996. He worked as a Project Officer for Turkish Armed Forces Integrated Communication Systems Project developed by Turkish General Stuff, from 1996 until 2001. He is currently a PhD student at the Electronics Engineering and Computer Science Department, Sabanci University, Istanbul, Turkey. His current research interests include Wireless Sensor Networks and Security for Ad hoc Networks. Vedat Coskun was born in Istanbul, Turkey, in 1962. He was graduated from Turkish Naval Academy, Istanbul, Turkey, in 1984. He received the M.Sc. degree from the Computer Science Department, Naval Post Graduate School, CA, USA, in 1990 and the Ph.D. degree from the Computer Engineering Department, Yildiz Technical University, Istanbul, in 1998. He managed the wargaming software development group in Turkish Naval Military Wargaming Center for 5 years. Hewas teaching assistant, faculty member and chairman with the Computer Engineering Department, Turkish Naval Academy. He was part-time visiting professor with Gebze Institute of Technology. He is currently an Assistant Professor with the Department of Information Technology, ISIK University, Istanbul, Turkey. His current research interests include algorithm design, wireless sensor and actuator networks, and cryptography Adnan Kavak was born in Usak, Turkey, in 1970. He received the B.S. degree from the Electrical and Electronics Engineering Department, Middle East Technical University, Ankara, Turkey, in 1992. He received the MS and PhD. degrees from the Electrical and Computer Engineering Department, The University of Texas at Austin, TX, USA, in 1996 and 2000, respectively. He was a satellite control engineer with Turksat Satellite Control Center, Ankara, Turkey, from December 1992 to May 1994. He worked as a Senior Research Engineer at Wireless Systems Laboratory, Samsung Telecommunications America in Richardson, TX, USA, from January 2000 to July 2001. He then joined Kocaeli University, Turkey, in August 2001 and worked as an Assistant Professor there until May 2005. Currently, he is the director ofWireless Communications and Information Systems (WINS) Research Center, and an Associate Professor with the Computer Engineering Department, Kocaeli University, Turkey. His current research interests include 3G and next generation wireless networks, software radios, smart antenna systems, resource allocation in 3G networks, and wireless sensor networks.     

Removal of trihalomethanes from drinking water by nanofiltration membranes

Chlorine reacts with the natural organic matter (NOM) in waters and forms disinfection by-products (DBP). Major of these by-products are trihalomethanes (THM) and haloacetic acids (HAA). They have been known to cause cancer and other toxic effects to human beings. This study determined the removal efficiencies of THM by nanofiltration (NF) techniques with NF200 and DS5 membrane. The rejection of this chlorination by-products was studied at various feed concentration by changing transmembrane pressure. Experimental results indicated that in general increasing operating pressure produces a higher flux but does not have a significant effect on THM rejection. On the other hand, increasing the feed concentration produces a little change in the overall flux and rejection capacity. NF200 membrane removed more THM than DS5 membrane. The higher removal efficiency of dibromochloromethane (DBCM) was attributed to brominating characteristics (higher molecular weight (MW) and molecular size). As a consequence, the results of this study suggest that the NF membrane process is one of the best available technologies for removing THM compounds.     

The optimization of the surface roughness in the process of tangential turn-milling using genetic algorithm

Turn-milling is a relatively new process in manufacturing technology, where both the workpiece and the tool are given a rotary movement simultaneously. This paper presents an approach for optimization of cutting parameters at cylindrical workpieces leading to minimum surface roughness by using genetic algorithm in the tangential turn-milling process. During testing, the effects of the cutting parameters on the surface roughness were investigated. Additionally, by using genetic algorithms for each of the cutting parameters (depth of cut, workpiece speed, tool speed and feed rate) minimum surface roughness for the process of tangential turn-milling was determined according to the cutting parameters.     

Influence of interstitial filling on breakage kinetics of gypsum in ball mill

Gypsum is an industrial material used in many applications such as building and chemical industry, fertilizer manufacture, medicine and dentistry. In these industries, there is need for finely ground gypsum. Energy consumption is very high in grinding processes. Therefore, the effects on breakage kinetics of powder filling and ball filling were investigated on gypsum samples taken from the Denizli-Honaz region (Turkey), for batch grinding conditions based on a kinetic model. For this purpose, firstly, eight different mono-size fractions between 1.7 mm and 0.106 mm formed by a √2 sieve series were obtained. Then, S_i and B_i,j equations were determined from the size distributions at different grinding times, and the model parameters (S_i, a_T, α, γ and ?_j) were compared for five different proportions of powder filling (5%, 7.5%, 10%, 15% and 20%), and three different proportions of ball filling (25%, 35% and 45%). Finally, model parameters are discussed for each test.From the result of tests, obtained of the effect of ball filling and powder filling on the grinding, it was found our results differed from those of other investigators.     

A Phoneme-Based Approach for Eliminating Out-of-vocabulary Problem Turkish Speech Recognition Using Hidden Markov Model

Since Turkish is a morphologically productive language, it is almost impossible for a word-based recognition system to be realized to completely model Turkish language. Due to the fact that it is difficult for the system to recognize words not introduced to it in a word-based recognition system, recognition success rate drops considerably caused by out-of-vocabulary words. In this study, a speaker-dependent, phoneme-based word recognition system has been designed and implemented for Turkish Language to overcome the problem. An algorithm for finding phoneme-boundaries has been devised in order to segment the word into its phonemes. After the segmentation of words into phonemes, each phoneme is separated into different sub-groups according to its position and neighboring phonemes in that word. Generated sub-groups are represented by Hidden Markov Model, which is a statistical technique, using Mel-frequency cepstral coefficients as feature vector. Since phoneme-based approach is adopted in this study, it has been successfully achieved that many out of vocabulary words could be recognized.