• Proceedings of the IEEK Conference
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.946-949
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• 1999

In this research we have developed a reliable, effective and feasible HEI(High-Energy Ion Implantation) process 3D-simulation tool, and then by using it we can predict and analyze the effect of HEI process on characteristics of the standard CMOS device. high-energy ion implantation above 200 keV is inevitable process to form retrograde well and buried layer to prevent leakage current, to conduct field implant for field isolation, and to perform after-gate implantation. The feasible analysis tool is a product of the HEI process modeling verified by comparison of the SIMS experiments with the simulation results. Especially, in this paper, we present the predicting capability of HEI-induced impurity and damage profiles compared with the published SIMS data in order to acquire the reliability of our results ranging from few keV to several MeV for phosphorus and boron implantation.

• School Mathematics
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• 제3권1호
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• pp.75-99
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• 2001

The purpose of this study is to develop concept map as a tool of performance assessment in mathematics and to conduct feasibility test of the task. I developed and applied a concept map, an assessment tool, in the form of a mathematics performance task for 1st and 2nd year middle school students. I also conducted feasibility test of the task, and at the same time sought ways to guarantee reliability of the assessment procedure. Results of the task assessment can be summarized into the following four points. First, the concept map task was found to be appropriate for an assessment of mathematics in middle school. Second, results of all 10 factors on verification of validity of the content of the task were positive with over 50%. Third reliability of teachers who conducted marking of the four concept map tasks was high, all recording over .871 in correlation number.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.866-869
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• 2000

The finishing process for die is an important process because it has influence on final quality of products. And it is difficult to automatize finishing process so that the process has depended on expert's skill until now. However, recently a study on development of die automatic finishing machine has been progressed, and actually this machine is applied to fabrication of die. But die automatic finishing machine has the problems such as low supply rate and high machine price. In this paper 3-axis machine was applied to the die finishing. And to improve form accuracy of die finishing path was regenerated. The finishing path considered tilting of finishing tool. and variation of machining force with contacting point between finishing and workpiece.

• Journal of the Korean Society for Precision Engineering
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• 제17권9호
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• pp.53-61
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• 2000

The manufacture of a marine propeller typically requires long lead time to generate 5-axis tool path. Hence it may take several weeks to manufacture a satisfactory propeller with a general purpose CAD/CAM system. In this research a dedicated 5-axis CAD/CAM system for machining marine propellers has been developed, The system employs various methods to enhance the productivity : interference-free tool path generation employing check vectors and optimum cutter size determinants. In addition an iterative NURBS modeling technique is used to improve the accuracy of the modeled surface and effective cutting conditions are determined and recommended empirically to increase the productivity. The proposed CAD/CAM system has been implemented with C++ and OpenGL graphic library on the Windows system. The system validation and sample results are also given and discussed.

• Journal of the Korean Society for Precision Engineering
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• 제12권2호
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• pp.87-96
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• 1995

The cutting force is the most important variable to understand the mechanics of ultra-precision machining. Most dynamometers, however, monitor the static cutting force only. But it is necessary to measure the dynamic cutting force to clarify the machinability of the material, the formation of the chip, chatter and the wear of the tool. In this research, measurement of the dynamic cutting force in order to clarify the machin-ability of the material, the formation of the chip, chatter and the wear of the tool has been conducted. A combined-type dynamometer which could measure the static cutting force and the dynamic cutting force by use of strain gauges and a piezo-film accelerometer has been developed. An analysis of the dynamometer also has been carried out.

• Journal of Korean Institute of Industrial Engineers
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• 제26권2호
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• pp.165-170
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• 2000

In order to perform a successful material cutting process, the operators are to select the suitable machining tools and cutting conditions for the cutting environment. Up to now, this has been a complicated procedure done by the data in the tool manufacturers' paper catalog and the operator's experiencial knowledge, so called heuristics. This research is motivated by the fact that using computer techniques in processing vast amount of data and information, the operator can determine the tool and cutting condition easily. In the developed program, the selection of milling cutter, insert, and components are combined to provide optimal cutting speed, depth of cut, feed rate, rpm, and power. This program also provides the selection routine for end mill, drilling, turning, and grinding where the suitable tools are selected by workpiece, holder type, cut type, and insert shape.

• Journal of the Korean Operations Research and Management Science Society
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• 제37권4호
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• pp.161-180
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• 2012

We develop some evaluation tool and indicators for the scores for medical equipment replacement in hospital. There has been no research for Korean hospitals although there are many for foreign medical institutions. In this paper, among many variables that were obtained from the previous studies, eleven variables are selected as indicators and tied as three groups. And then we obtain scores of medical equipments based on the weighted values of those indicators. We can make decisions whether we replace medical equipments or not by ranking the medical equipments based on the scores. This paper shows that we can make decisions to replace medical equipments very objectively and effectively using the evaluation tool and indicators we develop.

• Asian Journal of Atmospheric Environment
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• 제9권3호
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• pp.222-227
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• 2015

The environmental education with ideal teaching tools (e.g., a small-scaled experimental kit) is essential for raising the public's, especially student's, awareness of many environmental issues. This study was undertaken to develop a do-it-yourself model instrument of acid rain and estimating its applicability to the environmental education. Our novel model tool consists of a body (17 cm width, 6 cm depth, and 17 cm height), an acid gas injector, acid four rain reservoirs, and a drop supply pump. An alternative model instrument that can be more readily assembled was also suggested. Based on our novel approach, we carried out several model experiments with educatees (i.e., high school and college students, and adults). The results of questionnaires indicated that educatees achieved a very deep understanding of acid rain through an experienced model experiment. A 77 to 89% of educatees experienced the reappearance experiment of acid rain by our model instrument felt that it was very useful as a teaching tool of environmental education.

• The Transactions of the Korea Information Processing Society
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• 제7권2S호
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• pp.666-677
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• 2000

In this paper, we present a design and implementation of HDML(Handheld Device Markup Language) authoring tool that can create and mange HDML documents easily and conveniently, HDML is a markup language which enable acces to the Web using small mobile equipment through mobile networks. The basic limitation of mobile equipments and technical difficulties such as representation of HDML deck/card, definition of activation in each card and management of Hyper-link between cards are solved, in the development process of the HDML authoring tool.

• Transactions of Materials Processing
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• 제17권4호
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• pp.263-271
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• 2008

Process design is carried out for a press forming of a CTBA in the rear suspension assembly based on the result of the finite element analysis. The analysis simulates the two-stage stamping process with the initial design and it fully reveals the unfavorable mechanism which develops inferiorities during forming. In this paper, a new design guideline is proposed to modify the process and tool shapes for a single-stage forming process. With the improved tool design, prototypes are fabricated after several try-out processes. Results of the durability tests show that the design requirement of the part is satisfied and the effective weight reduction is achieved.