• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.603-608
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• 2005

Disk I/O is a major performance bottleneck of web proxy server. Today's most web proxy sowers are design to run on top of a general purpose file system. But general purpose file system can not efficiently handle web cache workload, small files, leading to the performance degradation of entire web proxy servers. In this paper we evaluate the performance potential of raw disk to reduce disk I/O overhead of web proxy servers. To show the performance potential of raw disk, we design a storage management system called Block-structured Storage Management System (BSMS). And we also actually implement web proxy server that incorporate BSMS in Squid. Comprehensive experimental evaluations show that raw disk can be a good solution to improve disk I/O performance significantly for web proxy servers.

• Earthquakes and Structures
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• v.9 no.4
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• pp.893-910
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• 2015

Earthquake safety of existing buildings has gained considerable importance after earthquakes which have occurred in our country especially in the last 30 years. Performance based assessment methods have been widely used for existing reinforced concrete structures. This study aims to investigate the earthquake performances of the building stock located in Van Lake basin in Eastern Anatolia of Turkey. The case study of buildings has been modeled on and the structural performances have been determined by employing the non-linear methods described in the latest Turkish Earthquake Code published in 2007. The Van lake basin is located on the very seismically active in a region. On October 23, 2011, a magnitude of Mw 7.2 earthquake struck the Van province in eastern Turkey. The earthquake ground motion was recorded as about 0.1g in Bitlis province. Performance evaluations have been performed by taking samples from each district consisting urban building stocks of Bitlis. A total of 16 reinforced concrete buildings have been evaluated. Among them, 53% of those buildings were determined in the Fully Operational performance level; 13% of them in the Life Safety performance and 34% of them could not be evaluated because of the ratio of the effective mass of first mode to the total mass of the buildings was smaller than 0.70. Therefore, incremental equivalent seismic load methods, which are a part of Turkish Earthquake Code -2007, cannot be used.

• KIEAE Journal
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• v.11 no.6
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• pp.29-35
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• 2011

This study aims to suggest improvement plans and explain about the current situation for facilitating Long-life housing, based on the results on flexibility items among 27 items consisting the "Housing Performance Grading System". From the 9th of January, 2006 to the month of July in 2011, study has analyzed evaluation results on 216 different types for each grade and reviewed evaluation criteria and methods. Current evaluation criteria applies quantitative analysis, by calculating in percentage how much bearing walls and columns, which hinder flexibility, take up space in the household. The evaluation rate for each household was assessed in relation to its structural system, and a higher grade was given to column-typed structures. In addition, to facilitate long-life housing, this study extracted harmful factors, expanding the range of evaluation. The first step was to evaluate structure, which is the basic element. The second step can to evaluate the probability of applying resources in response to the changes of structural systems. As The third step, Flexibility item will evaluate the probability of moving the water-using area, suggesting gradual approach. Thus, through evaluations of flexibility items, the study aims to improve the quality of life in household, by avoiding uniform structures and acquiring more freedom for space designs.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.462-475
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• 2007

The Embedded system provides human-centric services in many fields of education, information, industry and service, and monitoring programs have been variously developed for managing, controlling and testing for these embedded systems. Currently, many kernel trace toolkits are being used for monitoring. These trace toolkits are so complicate that we present $ETT^{plus}$, our simple and explicit embedded kernel trace toolkit, for embedded systems and describe the transmission method for trace data between the embedded target system and the host system. $ETT^{plus}$ provides the solution to solve the problems such as the difficult kernel patch and file system dependency in existing kernel trace toolkits like LTT. Furthermore, we present the experimental results about embedded system performance evaluations such as system call execute time or network data transmission time by using $ETT^{plus}$.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.431-440
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• 2015

Objective : The purpose of this study was to investigate the relations between accuracy score and the motions which are performed in PyeongWon Poomsae, thereby developing objectivity in accuracy evaluations for Poomsae competitions. Method : The subjects were six male Poomsae players (age: $21.2{\pm}1.17yrs$, height: $173.4{\pm}3.95cm$, weight: $67.7{\pm}7.65kg$). A three-dimensional motion analysis was performed on the subjects using six high-speed cameras (60 frames/sec) and subjects' performed motions were evaluated by 5 evaluators. The entire Pyeong Poomsae was divided into 13 events and 9 phases; there were three pairs of symmetric phases among them: front kick & turning side kick phases (3PH, 3-1PH), arm motion & stance phases (4PH, 4-1PH), side kick with Hakdari-stance phases (5PH, 5-1PH). Performance time, change and range of COM, height of vertex, and foot of side kicks were analysed. The Data was analysed utilizing correlation analysis. Results : There was a positive correlation between accuracy score and the difference between right and left range of COM (X direction) at 4PH (r=0.921, p=0.009). Conclusion : The results of our study indicate that it is necessary to consider some of objective criterion such as performance time, COM range, and symmetrical movements in accuracy evaluations of Poomsae competitions.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.157-162
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• 2001

Internet shopping mall is done commercial trade in particular web sites, and zoomed with an important means of trade for the next generation. When users visit shopping mall, the best objective is determined to users by of offering satisfaction and pleasant experience. Therefore. this paper was selected a menu list as an evaluation factor to emphasize a usage convenience of internet shopping mall, and executed a performance and a subjective satisfaction evaluations on a screen design and a structure design. The results of all the performance and the subjective evaluations for the screen design were shown the shortest search times on left type of the main-menu and vertical type of the medium-menu. In the structure design, it was shown that users were the highest satisfaction in type that search product and shopping cart procedure were firstly processed, and the procedure of a shopping membership and paying a bill were secondly processed at the same screen with regard to a comprehensibility and convenience of purchase procedure. It was shown that the user prefered the shopping mall web site to analogy with the real purchase procedure

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.641-648
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• 2011

During practices of traffic management, the performance achieved was determined by traffic practitioners' ability of decision and knowledge as well as traffic equipments assisting the practitioners. Therefore, sometimes self-evaluations done by the traffic practitioners in a specific traffic organization can be used to indirectly evaluate the traffic management organization. The present paper is to evaluate a specific highway agency using self-evaluations performed among different highway agencies including one Japanese highway agency. The result indicated that the agency is superior to other agencies in characteristics such as performance, activity, preparation for the future, and customer orientation. For more detailed-branch based study, the responders were divided into their belonged branches like headquarter, regional headquarter, maintenance office and research center. The results provided that various deficiencies of traffic management were found and could be improved in the future.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.79-87
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• 2011

Although products with the fingerprint recognition system currently show a rapid growth in quantity, it is also true that efforts to consider the product quality have been lacking until now. Accordingly, this paper analyzed technological elements with domestic and foreign market situations for products with the fingerprint recognition system to develop an evaluation model to support the quality increase by evaluating aspects of product quality for the knowledge information security, identifying the level of quality and deriving directions for improvements. A model for the reliability quality evaluation was constructed that can be applied comprehensively to non-functional elements that have not been done in the existing evaluations central to the security functions by analyzing requirements for the security, performance and reliability in consideration of features on products. It is considered that this paper can make contributions to the overall quality increase for products with the knowledge information security by reflecting features and trends for the fingerprint recognition products and building a model for the reliability and evaluation to perform evaluations by product.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.3
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• pp.147-154
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• 2003

This paper presents a high-frequency boost type ZVS-PWM chopper-fed DC-DC power converter with a single active auxiliary edge-resonant snubber at the load stage which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of boost type ZVS-PWM chopper proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory and the temperature performance of IGBT module, the actual power conversion efficiency, and the EMI of radiated and conducted emissions, and then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn-off mode transition with the aid of an additional lossless clamping diode loop, and can be reduced the EMI conducted emission.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.275-282
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• 2007

In this study, a fluid-structure interaction (FSI) analysis system has been developed in order to evaluate the turbine cascade performance with blade structural deformation effect. Relative movement of the rotor with respect to stator is reflected by modeling independent two computational domains. To consider the deformed position of rotor airfoil, dynamic moving grid method is applied. Reynolds-averaged Navier-Stokes equations with one equation Spalart-Allmaras and two-equation SST $k-{\varepsilon}$ turbulence models are solved to predict unsteady fluid dynamic loads. A fully implicit time marching scheme based on the Newmark direct integration method with high artificial damping is used to compute the fluid-structure interaction problem. Cascade performance evaluations for different elastic axis positions are presented and compared each other. It is importantly shown that the predicted aerodynamic performance considering structural deformation effect of blade can show some deviations compared to the data generally computed from rigid blade configurations and the position of elastic axis also tend to give sensitive effect.