• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.190-197
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• 2010

The ACR (Access Control Router) of WiBro processes location registration of the Correspondent Node and Home Agent as the Correspondent Node moves between ACRs. Therefore, the location update cost is low compared with MIPv6. However, all packets which are sent and received are sent through the ACR, so as the number of mobile nodes that are managed by the ACR increases, the cost of packet delivery also increases. Therefore, the communication state of the ACR domain remains smooth when the ACR which manages the mobile node in the ACR domain has good performance. However, network delays occur unless the ACR performs well, so the role of the ACR is important. In this paper, we analysis performance of the ACR for efficient realization of the WiBro standard. By using the Deny Probability and the Total Profit of ACR performance and apply it to the Random Walk Mobility model as the mobility model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.166-174
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• 2010

SSDs are one of the best media to support portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major database storage components for desktop and server computers. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of flash memory operations, as compared to RAM memory. In order to achieve this goal, we propose a new index management scheme based on a compressed hot-cold clustering called CHC-Tree. CHC-Tree-based index management improves index operation performance by dividing index nodes into hot or cold segments and compressing pointers and keys in the index nodes and clustering the hot or cold segments. The offset compression techniques using unused free area in cold index node lead to reduce the number of slow erase operations in index node insert/delete processes. Simulation results show that our scheme significantly reduces the write and erase operation overheads, improving the index search performance of B-Tree by up to 26 percent, and the index update performance by up to 23 percent.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.61-70
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• 2003

I-Business providers and customers have chosen the service availability as the most important technical parameter which should be included in their SLA to succeed in their business. This means that web Service availability management is crucial to the web-based service providers. Application availability is originally defined as a measure of the fraction of time during a defined period when the service provided is deemed to be better than user expectation of service performance. But, because most web service availability measurement tools simply monitor disconnected state, they do not satisfy user's expectation of extended availability concept. In this paper, We propose the web service availability measurement method which supports extended availability concept. It takes account of performance degradation of web service based on response time, and determines what is the cause of unavailability of the service. We developed a measurement tool, WebSerAvail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1113-1118
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• 2012

Smart grid and intelligent transportation system draw significant interest since they are considered as one of the green technologies. These systems require a large number of sensors, actuators, and controllers. Also, machine-to-machine (M2M) communications is important because of the automatic control. The LTE-Advanced networks is preparing a set of functions that facilitate the M2M communications, and particularly the development of an efficient call admission control mechanism is critical. A method that groups MTC devices according to QoS constraints and determines the admission depending on the QoS satisfaction is limitedly applied only if the data transmission period and the maximum delay are identical. This paper proposed a call admission control that is free from such limitation and also optimizes the admission process under the certain condition of the transmission period and maximum delay. The theorems regarding the proposed method are presented with the proofs. The simulations confirms its validity and shows it is better in call admission probability than existing works.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5792-5799
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• 2013

The purpose of this study was the Application of the HACCP (Hazard Analysis Critical Control Point) system to Korean Rice Cakes. Main ingredients of rice cakes, work facilities and workers were provided from KB company located in Seogye-dong Yongsan-gu, Seoul between September 12, 2012 and February 13, 2013. The manufacturing process chart was prepared by referring to the manufacturing process of rice cake manufacturers in general. As a result of this study, the microbiological hazard analysis on raw materials and finished products of rice cakes showed safe result. However, microorganism test on the manufacturing environment and workers suggested that microbiological hazard should be reduced through systematic cleaning and disinfection, accompanied by improved personal hygienes based on hygienic education on workers and management of microorganisms in the air.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2767-2772
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• 2013

Balance is the foundation for all active daily livings. Evaluation of balance has been conducted to measure postural sway of center of pressure(COP). The purpose of this study is to introduce the Balancia and to examine the validity and inter-, intra-reliability for measure of balance with stroke patients. COP was measured by Wii balance board. The subjects Participated in this study were 39 stroke patients. Intra- and inter-reliability was examined using intraclass correlation coefficient(ICC) with 95% confidence interval. In the result of intra- and inter-reliability, all COP parameters of postural sway showed high to very high reliability with ICC=.793-.939 and ICC=.791-.955. Validity was determined by correlation with Accusway force plate. There were high validity with ICC=.851-.955 between tools. According to these results, the Balancia showed high validity and reliability. It is a useful clinical tool for evaluating balance in stroke patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.605-612
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• 2017

Climate change affects the natural ecosystem and human socioeconomic activities by acting on various constituents such as the atmospheric, oceanic, biological, and land constituents of the climate. Predicting the impacts of ongoing climate change will be an important factor in adapting to the climate of the future. In this study, precipitation-streamflow elasticity analysis of the Nakdong River area was conducted using the RCP 4.5 scenario developed by the IPCC (Intergovernmental Panel on Climate Change). Precipitation and streamflow in the Nakdong River area was analyzed using monthly, seasonal, and yearly data. Results found that the climate would become very humid climate by 2100. Results of this study can be applied to adaptation of climate change, management of water resources and efficient utilization of hydraulic structures.

• Journal of Information Management
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• v.41 no.1
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• pp.69-95
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• 2010

In this study, we study on the actual conditions of which Korean law school libraries are being operational. Because the successful law school library management means the success of the law school education, guarantees the success of expert education on our laws area. Therefore, this study propose the methods which is designing the content of the law school library website. As a result, an independent law school libraries are 21 (84%). During the law school library websites which are specialized contents with related the law are 15(71%). This website is based, menu of law school library's websites through the analysis of the content are analyzed. Based on this analysis, seven content composition elements that should be service to law school library is proposed in this study.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.623-627
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• 2014

Emulsions are a class of disperse systems consisting of two immiscible liquids. Emulsions are affected by the size of oil drop, the type of continuous and disperse phase, the ratio of continuous and disperse phase, the type of emulsifies and emulsification devices. This study is to observe the viscosity of emulsions with oil polarities and interpret the results by organic conceptual diagram. The emulsions were made with hydrocarbon, ester and silicone oils and then the viscosity of emulsions was measured. As the oil polarity was increased, the viscosity of emulsion was decreased by reducing the amount of emulsifies and emulsion stabilizers arranged at interface. Organic conceptual diagram was used to compare the polarities among oils numerically. The interpretation of organic conceptual diagram and the results of experimental measurement were corresponded except emulsion made with silicone oil.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.441-450
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• 2006

WiBro(Portable Internet Service) is service being capable to provide a high data rate wireless internet access with Personal Subscriber Station under the stationary or mobile environment, anytime and any where. It will fill the gap between very high data rate wireless local area networks and very high mobility cellular systems. The security is an important point of WiBro providing high data and mobile wireless services. This paper proposes user authentication mechanism of WiBro wireless networks applied EAP-AKA authentication protocol. As a result of Wireless authentication based on EAP-AKA, this mechanism is capable to be used in WiBro-WLAN-3GPP interworking scenario as well as the WiBro authentication mechanism.