• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.107-113
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• 1996

This paper presents the experimental results on the cutting performance and wear characteristics of CBN ball end-mill. The influence of cutting fluids and rake angles on the tool performance is reported. It i found that the neat cutting oil is beneficial to obtain good surface roughness and 30 .deg. of rake angle gives the minimum tool wear. The microscopic investigations reveal that the coated carbide endmills wear by fracture whereas the CBN endimills wear by attritious mode.

• Tribology and Lubricants
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• v.13 no.3
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• pp.102-107
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• 1997

Diamond grit was coated with Ti by RF Sputtering to investigate the effect of coated diamond particles on performance of diamond impregnated saw. Coated and uncoated powders were separately mixed with 70Co-30W powders by conventional milling technique. Hot pressing was carried out to make specimens. The wear test were carried out with these two types of diamond impregnated specimens. It was demonstrated that Ti coating was effective in improving the ability of grit retention and thus enhanced the tribological performance of diamond tool.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.106-109
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• 2006

The purpose of this study is to analyze the installed performance of the PW206C turbo shaft engine used in the development of the smart UAV(Unmanned Ariel Vehicle) by KARI(Korean Aerospace Research Institute). It mainly aims to investigate performance behavior at installed conditions using both inlet and exhaust losses generated by CFD analysis of the ducts. The ways employed to be able to analyze the performance extensively were mainly rallied out by performing design point analysis of the engine where the performance simulation results from the commercial program 'GASTURB 9' used for simulation were used as inlet boundary condition for the ducts in CFD program The use of CFD tool involve modeling of the ducts to conform with the stipulated shape and sizes as defined by KARI with a grid density that allows reasonable flow characteristics applicable to aircraft components. Respective values of Shaft horse power obtained by varying flight Mach number, Gas generator RPM and Altitude considering several losses inclusive of those estimated by use of CFD tool were then plotted at three conditions with the ECS-OFF, ECS-MAX and at un-installed condition. Reasonable results were obtained as a result of using computational fluid dynamics that can hence be justified as an alternative tool for use in future flow analysis of engine and components.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.1-11
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• 2010

Many applications of DSMS(Data Stream Management System) require not only to process real-time stream data efficiently but also to provide high quality services such as data mining and data warehouse combining with DBMS(Database Management System) to users. In this paper we execute the performance benchmark of the combined system of DSMS and DBMS that is developed for high quality services. We use the stream data of network monitoring application system and combine the traditional representative DSMSs and DBMSs in a single system for the performance testing. We develop the total performance benchmark tool implementing JAVA language for the our testing. For our performance testing, we combine DSMS such as STREAM and Coral8 and DBMS such MySQL and Oracle10g respectively.

• Journal of The Korean Association of Information Education
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• v.20 no.3
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• pp.255-262
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• 2016

In this paper, we proposes a method to effectively evaluate learner competencies of computational thinking. Developed descriptive performance assessment tool is the use of assessment items presented in a creative computing MIT. This tool is selected and modified items through expert delphi technique. The performance assessment tool is composed of four areas that are an experimenting and iterating, testing and debugging, reusing and remixing and abstracting and modularizing. We apply to software classes for the pre-service teachers and conducted this descriptive performance assessment. Applying result of the assessment, the developed assessment tool shows the reliability $Cronbach-{\alpha}$ values higher than 0.6. In addition, the validity of the test results is higher in experts delphi test. Descriptive assessment tool suggested in this study are identified as a useful assessment tool to effectively measure student CT competencies.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.1-10
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• 2003

A recent trend In flexible manufacturing systems (FMS) Is to utilize the Identical versatile machines with fast tool delivery devices. Unlike a conventional FMS where parts are fed to the machines with the required tools, tools are acquired from other machines using a tool delivery system and parts can be finished on the same machine In these FMS. Therefore it Is more important problem 4o plan tool flow using tool delivery system In these FMS rather than part flow In conventional FMS. According to the existing study, In FMS 20∼30 percent of the total management cost Is the cost related with tools and It Is possible to reduce the tool Inventory by 40 percent using efficient tool allocation. In this study, In FMS under dynamic tool allocation strategy, a new method of part release considering tool flow at the stage of part release Is proposed. In order to prove the efficiency of the proposed part release It is compared with other part release through simulation experiments. Performance measures in these experiments are the throughput and the number of tardy parts.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.5
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• pp.203-208
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• 2016

Information system audit is the requirement to configure the information system successfully. However, there is a problem with reduction of efficiency in the audit work when the system capacity is growing up. In the subsidiary field of information system audit, there is the same problem. In this paper, we will focus on the database audit, and implement an SQL audit tool in order to improve the performance of a database. During the designing phase of the SQL audit tool which aim to improve the performance of a database, we have analyzed the requirements of SQL audit work. Based on the aforementioned them, the process of the SQL audit tool has been designed with SQL audit features in accordance with information audit process. During the implementation phase, we have implemented 3 main function modules according to the output of the design phase. The main modules we implemented are the audit job definition module, audit job executing module and result reporting module. With the implemented tool, it applied to an Electric Power Corporation project in China and compared with other tools that are able to use SQL audit. In this paper, the implemented SQL audit tool is able to perform the general SQL audit work and to reduce the cost of the audit work for database performance and to raise the accuracy of result and to apply the extended inspection rule which need to use SQL parsing.

• Journal of Nutrition and Health
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• v.37 no.4
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• pp.310-315
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• 2004

The purposes of this study were to: a) develop the quality assessment tool of Web-based Instruction (WBI) for nutrition education, b) evaluate the operated WBI (NutriZone) by this tool, and c) do the feasibility study about quality assessment tool for WBI by establishing the instruction and operating strategies. The developed quality assessment tool of WBI for nutrition education was divided into three categories of instruction design, contents and support ＆ operation. And a total of forty items were measured by Likert 5 point scale, computed as one point per item, and amounted to forty points in all. As a result of evaluation, NutriZone got 21.79 out of 40 points and fulfillment rate of 54.5%. The IPA (Importance-Performance Analysis) was applied to establish the instruction and operating strategies, and nine items characterized as attractiveness, multimedia, and learner-initiative were in 'Doing Great, Keep It Up', and so it was regar-ded as program designed with concern in WBI's characteristics unlike the conventional face-to-face education. But twelve items such as 'Errors on switch to other screens are few.', 'Ready correction leads to be out of systemic error.', 'Highlight marks and moving pictures were used in sign of importance.' and etc. that got high importance and low performance needed to be focused in instructional strategy.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.4
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• pp.154-160
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• 2002

Powder metallurgy(P/M) process has been used for the production of high performance high-speed steels. P/M high speed steel has more uniform and fine microstructure than those of conventional wrought products. Therefore, it offers distinct advantages over conventional tool steels. The superior uniformity of composition and fine microstrucure lead to excellent toughness and less distortion during heat treatment, which in turn can reduce total grinding costs and provides other benefits, such as uniform hardness and increased tool life. From these reasons, milling, hole machining, broaching, and gear manufacturing tools are major applications of P/M high-speed steels. In this research, we evaluated tool wear of flat endmill which is made of P/M high-speed steel from the view point of cutting tool performance.

• Journal of Korea Game Society
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• v.11 no.1
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• pp.37-46
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• 2011

Due to the advent of high performance feature-phone and smart-phone, the scale of mobile games and the member of developers are increased rapidly. The production process of mobile games is changing to meet these needs. Tools for efficient program development are produced worldwide, but tool's research for the event direction is inadequate. In the event direction, the game designers play more important roles than programmers. In this paper, we develop the mobile game event direction tool for game designers. And we make the events of the released mobile games to test the efficiency and usefulness of tool that we developed. The result shows that the performance is enhanced about 15% in development period.