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Wonju, South Korea

Sangji University is a private university located in Wonju, Gangwon Province, South Korea. Established in 1955, it has seven colleges and six graduate schools. Its top areas of study are Oriental Medicine and Tourism. The Sangji Foundation also manages Sangji Yeongseo College and Sangji Girls Middle and High Schools. Wikipedia.

Chu Y.H.,Sangji University | Shul Y.G.,Yonsei University
International Journal of Hydrogen Energy | Year: 2010

Low-temperature direct alcohol fuel cells fed with different kinds of alcohol (methanol, ethanol and 2-propanol) have been investigated by employing ternary electrocatalysts (Pt-Ru-Sn) as anode catalysts. Combinatorial chemistry has been applied to screen the 66-PtRuSn-anode arrays at the same time to reduce cost, time, and effort when we select the optimum composition of electrocatalysts for DAFCs (Direct Alcohol Fuel Cells). PtRuSn (80:20:0) showed the lowest onset potential for methanol electro-oxidation, PtRuSn (50:0:50) for ethanol, and PtRuSn (20:70:10) for 2-propanol in CV results respectively, and single cell performance test indicated that Ru is more suitable for direct methanol fuel cell system, Sn for direct ethanol fuel cell system, and 2-propanol could be applied as fuel with low platinum composition anode electrocatalyst. The single cell performance results and electrochemical results (CV) were well matched with the combinatorial electrochemical results. As a result, we could verify the availability of combinatorial chemistry by comparing the results of each extreme electrocatalysts compositions as follows: PtRuSn (80:20:0) for methanol, PtRuSn (50:0:50) for ethanol and PtRuSn (20:70:10) for 2-propanol. © 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Kim C.,Sangji University | Klimenok V.I.,Belarusian State University | Dudin A.N.,Belarusian State University
Computers and Operations Research | Year: 2014

A multi-server retrial queue with two types of calls (handover and new calls) is analyzed. This queue models the operation of a cell of a mobile communication network. Calls of two types arrive at the system according to the Marked Markovian Arrival Process. Service times of both types of the calls are exponentially distributed with different service rates. Handover calls have priority over new calls. Priority is provided by means of reservation of several servers of the system exclusively for service of handover calls. A handover call is dropped and leaves the system if all servers are busy at the arrival epoch. A new call is blocked if all servers available to new calls are busy. Such a call has options to balk (to leave the system without getting the service) or to retry later on. The behavior of the system is described by the four-dimensional Markov chain belonging to the class of the asymptotically quasi-Toeplitz Markov chains (AQTMC). In the paper, a constructive ergodicity condition for this chain is derived and the effective algorithm for computing the stationary distribution is presented. Based on this distribution, formulas for various performance measures of the system are obtained. Results of numerical experiments illustrating the behavior of key performance measures of the system depending on the number of the reserved servers under the different shares of the handover and the new calls are presented. An optimization problem is considered and high positive effect of server's reservation is demonstrated. © 2013 Elsevier Ltd.

Oh S.Y.,Gachon University | Chung K.-Y.,Sangji University
Cluster Computing | Year: 2014

Speech recognition systems for the automobile have a few weaknesses, including failure to recognize speech due to the mixing of environment noise from inside and outside the car and from other voices. Therefore, this paper features a technique for extracting only the selected target voice from input sound that is a mixture of voices and noises. The feature for selective speech extraction composes a correlation map of auditory elements by using similarity between channels and continuity of time, and utilizes a method of extracting speech features by using a non-parametric correlation coefficient. This proposed method was validated by showing that the average distortion of separation of the technique decreased by 0.8630 dB. It was shown that the performance of the selective feature extraction utilizing a cross correlation is good, but overall, the selective feature extraction utilizing a non-parametric correlation is better. © 2013 Springer Science+Business Media New York.

Kim J.,BIT Computer Co. | Chung K.-Y.,Sangji University
Multimedia Tools and Applications | Year: 2014

To establish real u-healthcare environments, it is necessary to receive the context information obtained from various platforms at the proper time in portable devices which operate using both wired and wireless communication. Moreover, a knowledge model is required that reflects the information and characteristics needed for such services while remaining appropriate for medical reference. This paper develops an ontology-based healthcare context information model to implement a ubiquitous environment. Contextual information will be extracted and classified to implement the healthcare services using the context information model. The healthcare context information model can be defined using the ontology, and a common healthcare model will be developed by considering medical references and service environments. Application and healthcare service developers can use the sensed information in various environments by authoring device- and space-specific ontologies based on this common ontology. In addition, this paper designs a personalized u-healthcare service system. The validity of the model used in this study is evaluated for the food and exercise recommendation in u-healthcare services. © 2011 Springer Science+Business Media, LLC.

Kim S.-H.,Sangji University | Chung K.-Y.,Sangji University
Multimedia Tools and Applications | Year: 2014

This paper describes the development of a 3D simulator that enables a user to analyze the stability of a finite slope causing plane activity among a range of slopes comprised of a finite slope and infinite slope. Until now, there has been considerable theory and research into slope stability. Nevertheless, few systems can be confirmed directly by simulating the stability analysis of a slope, such as landslides. In: other words, virtual experiments, such as the analysis of the slope, cannot be performed due to the absence of a system. For that reason, in this study, a 3D simulator was developed for stability analysis of a finite slope causing plane activity from the landslide phenomena that actually occurred or had very high probability. The Nvidia PhysX, which is utilized to develop computer games and simulators, was used to develop a 3D simulator with physical features. In: addition, OpenGL was used to provide a three-dimensional visual effect from the simulator. In: this paper, the values of each variable were determined to confirm whether landslides can occur easily when the factor of safety (F s ) was within a certain range in the 3D simulator. The 3D simulator developed in this paper was found to be quite useful because it can verify visually whether landslides occur easily in different environments and conditions. © 2013 Springer Science+Business Media New York.

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