• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.43-49
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• 2018

Computer simulation was performed using the SIMION program to develop an electron gun for MCP cleaning. The target, MCP, is located 180mm from the source of the electron gun, and the diameter of the MCP is approximately 20mm. Therefore, we tried to find the condition that the beam diameter of electrons reaching the MCP is to be 20mm using four variables such as E, ${\phi}$, d1, d2, where the E is the energy of the electron reaching the MCP, the ${\phi}$ is the diameter of the extractor, and the d1 and the d2 are the distance from the electron source to the end of the extractor tube, and to the wall of chamber, respectively. As a result of simulation, we figuried out that the E and the d2 have little effect on the beam diameter. On the other hand, we also found that the beam diameters were very sensitive to the d1 and varied relatively large with respect to the ${\phi}$, and the d1 was the secondary order function of the ${\phi}$. Therefore we found that this function will allow us to design electron guns that are suitable for the purposes of this study.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.67-78
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• 2008

The purpose of this paper is to discuss the design and implementation of a WCBT(Web and Computer based Test). The WCBT combines the strengths of both a WBT(Web-based test) and a CBT(Computer-based test) on the basis of efficiency and stability. The current assessment system, considered an important management tool in the construction and operation of a total management system for the national technical qualification, has some unstable elements with regard to system load and stability. The proposed system's technological aspects have been tested through a basic simulation pilot program. The pilot program will be expanded to include the local Chamber of Commerce and Industry because the stability of the system was proved through its application to the real-time national technical examination of KCCI (Korea Chamber of Commerce and Industry). The WCBT system has shown great efficiency in terms of system load, and has solved frequent communication problems which have occurred through the use of foreign qualifying examinations. The server and client systems of the WCBT have been given good evaluations with regard to the convenience of their use and the management system for operators and supervisors.

• Journal of the Korea Society for Simulation
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• v.22 no.3
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• pp.81-87
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• 2013

This paper is about study how to decrese surge pressure that is occurred in excavator driving motor. We used computer simulation program SimulationX. It is also about the way finding design problem and approaching a solution through interpreting shape design sensitivity analysis. Programmes are below. First of all, finding shape fault by analyzing dynamic behavior of valves installed in hydraulic driving motor which is designed now. And drawing variable which is considered sensitive to improve dynamic efficiency among a lot of shape variables. Then, targeting that variable and examining dynamic efficiency stabilization tendency with controlling it. Finally, suggesting the most effective tuning method through variable combination as there are a lot of sensitive variables.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.187-193
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• 2003

Purpose: To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Materials and Methods: Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta perch a at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. Results: H in the V group was slightly greater than that in the D group, and Wand X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and Wand X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. Conclusion: The results of the experiment show that the newly developed, inexpensive Vimplant/TM/ simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.566-571
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• 2014

Channel-stacked 3D NAND flash memory is very promising candidate for the next-generation NAND flash memory. However, there is an inherent issue on cell size variation between stacked channels due to the declined etch slope. In this paper, the effect of the cell variation on the incremental step pulse programming (ISPP) characteristics is studied with 3D TCAD simulation. The ISPP slope degradation of elliptical channel is investigated. To solve that problem, a new programming method is proposed, and we can alleviate the $V_T$ variation among cells and reduce the total programming time.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.589-590
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• 2006

전력 계통에서 과전류가 발생하게 되면 이것을 차단하기 위해 차단기가 동작한다. 차단기가 동작하게 되면 기계적으로 전기의 흐름을 단절시키므로 아크 현상이 발생한다. 이때 차단기의 차단 절차를 이해하기 위해서는 아크 현상의 모델링이 필요하다. 특히 포스트 아크 현상에 관한 정밀한 모델링이 이루어질 경우 차단기에서의 소호 특성을 파악하기 용이하다. 우리는 이 논문에서 전력 계통의 과도현상 분석 수치해석 프로그램인 EMTP(Electro-Magnetic Transient Program)를 이용하여 아크 현상에서 발견되는 포스트 아크 전류(Post-Arc Current) 및 TRV(Transient Recovery Voltage)를 반영하는 아크 모델을 설계하였다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2221-2222
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• 2006

전력 계통에서 과전류가 발생하게 되면 이것을 차단하기 위해 차단기가 동작한다. 차단기가 동작하게 되면 기계적으로 전기의 흐름을 단절시키므로 아크 현상이 발생한다. 이때 차단기의 차단 절차를 이해하기 위해서는 아크 현상의 모델링이 필요하다. 특히 포스트 아크 현상에 관한 정밀한 모델링이 이루어질 경우 차단기에서의 소호 특성을 파악하기 용이하다. 우리는 이 논문에서 전력 계통의 과도현상 분석 수치해석 프로그램인 EMTP(Electro-Magnetic Transient Program)를 이용하여 아크 현상에서 발견되는 포스트 아크 전류(Post-Arc Current) 및 TRV(Transient Recovery Voltage)를 반영하는 아크 모델을 설계하였다.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.569-572
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• 1999

This paper presents a method for designing an autopilot of the BTT missile using 2DOF Wiener-Hopf control technique to improve tracking performance. Linear controllers are designed based on the linearized models which are obtained from the nonlinear missile dynamic equations at various operating points. The gain scheduling technique is used to implement the final autopilot. A simulation on the flight of missiles is carried out through the use of 6DOF equation program including exact nonlinear equations of the missile and the variations of aerodynamic variables in order to check applicability of the suggested method in real situation.

• International Journal of Contents
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• v.2 no.1
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• pp.34-38
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• 2006

In this paper, an overview of anti-collision algorithm for RFID system of a standard EPC Class1 protocol is presented, and the binslotted dynamic search algorithm (BDS) based upon the slotted ALOHA and binary tree procedure is proposed and analyzed. Also, the performance is evaluated as comparing the BDS algorithm with the standard bin-slotted algorithm (BSA) through the simulation program. The performance of the proposed BDS algorithm is improved by dynamically identifying the collided-bit position and the collided bins stored in the stack of the reader. As the results, the number of request command that a reader send to tags in the reader s interrogation zone and the total recognition time are decreased to 59% as compared with BSA algorithm. Therefore, the tag identification performance is fairly improved by resolving a collision problem using the proposed BDS algorithm.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1255-1256
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• 2006

전력 계통에서 과전류가 발생하게 되면 이것을 차단하기 위해 차단기가 동작한다. 차단기가 동작하게 되면 기계적으로 전기의 흐름을 단절시키므로 아크 현상이 발생한다. 이때 차단기의 차단 절차를 이해하기 위해서는 아크 현상의 모델링이 필요하다. 특히 포스트 아크 현상에 관한 정밀한 모델링이 이루어질 경우 차단기에서의 소호 특성을 파악하기 용이하다. 우리는 이 논문에서 전력 계통의 과도현상 분석 수치해석 프로그램인 EMTP(Electro-Magnetic Transient Program)를 이용하여 아크 현상에서 발견되는 포스트 아크 전류(Post-Arc Current) 및 TRV(Transient Recovery Voltage)를 반영하는 아크 모델을 설계하였다.