• 대한기계학회논문집A
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• 제25권8호
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• pp.1294-1301
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• 2001

In order to reduce the time and cost for assembly, automobile speaker grills have been injection molded with door trims or map pockets in one piece recently. However, several defects such as short shots or air traps can easily occur due to the decreased fluidity of the melting polymer according to the excessive heat transfer to the mold. Therefore, it is necessary to optimize the resin feed system and predict possible defects by CAE analysis. However it is not possible to obtain exact analysis results for the speaker grill by using general shell elements since the heat transfer in the thickness direction which is the dominant factor of the filling stage can not be considered. Therefore, there have been several efforts to simulate the injection molding nature of the speaker grill by using shell elements with an effective thickness which is smaller than the actual thickness of the part. Two empirical values have been recommended for the effective thickness in real practice. One is 50∼70% of the thickness of the speaker grill and another is the gap distance between the adjacent holes. In this paper, CAE analyses of a map pocket with a speaker grill were conducted using shell elements with both of these recommended effective thicknesses, and the predicted flow fronts were compared with the findings from injection molding experiments. The commercial code MOLDFLOW was used for injection molding analysis and an 850 ton injection molding machine was used for experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.86-89
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• 2002

In NC machining, the ability to automatically generate an optimal process plan is an essential step toward achieving automation, higher productivity, and better accuracy. For this ability, a system that is capable of simulating the actual machining process has to be designed. In this paper, a milling process simulation system for the general NC machining was presented. The system needs first to accurately compute the cutting configuration. ME Z-map(Moving Edge node Z-map) was developed to reduce the entry/exit angle calculation error in cutting force prediction. It was shorn to drastically improve the conventional Z-map model. Experimental results applied to the pocket machining show the accuracy of the milling process simulation system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.695-697
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• 2006

Elshayal $Smart{\copyright}$ software is an almost First Arabian GIS $software{\copyright}$ which completely developed by Arabian developers team and independent of any commercial software package. The software current Features are View and Edit shape files, build new layers, add existing layers, remove layers, swap layers, save layers, set layer data sources, layer properties, zoom in & zoom out, pan, identify, selecting features, invert selection, show data table, data query builder, location query builder, build network, find shortest path, print map, save map image, copy map image to clipboard, save project map, edit move vertex, edit move features, snap vertexes, set vertex XY, move settings, converting coordinate system, applying VB script, copy selected features to another layer, move selected features to another layer, delete selected features, edit data table, modify table structure, edit map features, drawing new features, GPS tracking, 3D view, etc... The software expected Features are: Viewing raster image and image geo-referencing, read other map formats such as DXF Format and Tiger Line Format.

• 한국정밀공학회지
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• 제12권7호
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• pp.32-45
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• 1995

In this paper, we present a new method to tool path planning problem for rough cut of pocket milling operations. The key idea is to formulate the tool path problem into a TSP (Travelling Salesman Problem) so that the powerful neural network approach can be effectively applied. Specifically, our method is composed of three procedures: a) discretization of the pocket area into a finite number of tool points, b) neural network approach (called SOM-Self Organizing Map) for path finding, and c) postprocessing for path smoothing and feedrate adjustment. By the neural network procedure, an efficient tool path (in the sense of path length and tool retraction) can be robustly obtained for any arbitrary shaped pockets with many islands. In the postprocessing, a) the detailed shape of the path is fine tuned by eliminating sharp corners of the path segments, and b) any cross-overs between the path segments and islands. With the determined tool path, the feedrate adjustment is finally performed for legitimate motion without requiring excessive cutting forces. The validity and powerfulness of the algorithm is demonstrated through various computer simulations and real machining.

• 소성∙가공
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• 제14권5호
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• pp.452-459
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• 2005

Gas assisted injection molding (GAIM) is an innovative low-pressure injection molding technique that can provide numerous benefits such as reduced part warpage, excellent surface quality without sink marks, low injection pressure and greater design flexibility. However, adoptions of GAIM may cause unexpected defects since it requires many subtle design factors such as resin shot size, delay time and gas injection pressure, which wouldn't be considered in conventional injection molding process. Therefore, experiences applying GAIM should be collected and examined in order to establish design rules of the new technique. The purpose of this paper is to summarize developing cases of three automotive interior parts such as instrument panel, map pocket folding and center facia side panel so that possibilities and limitations of GAIM were examined. As a result, it is necessary to consider characteristics of GAIM at the initial stage of part design in order to obtain various advantages of the GAIM process without occurring severe defects, which would increase time and cost required to the part development.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.104-111
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• 2019

Purpose: Online magnetic resonance-guided adaptive radiotherapy (MRgART), an emerging technique, is used to address the change in anatomical structures, such as treatment target region, during the treatment period. However, the electron density map used for dose calculation differs from that for daily treatment, owing to the variation in organ location and, notably, air pockets. In this study, we evaluate the dosimetric effect of electron density override on air pockets during online ART for pancreatic cancer cases. Methods: Five pancreatic cancer patients, who were treated with MRgART at the Seoul National University Hospital, were enrolled in the study. Intensity modulated radiation therapy plans were generated for each patient with 60Co beams on a ViewrayTM system, with a 45 Gy prescription dose for stereotactic body radiation therapy. During the treatment, the electron density map was modified based on the daily MR image. We recalculated the dose distribution on the plan, and the dosimetric parameters were obtained from the dose volume histograms of the planning target volume (PTV) and organs at risk. Results: The average dose difference in the PTV was 0.86Gy, and the observed difference at the maximum dose was up to 2.07 Gy. The variation in air pockets during treatment resulted in an under- or overdose in the PTV. Conclusions: We recommend the re-contouring of the air pockets to deliver an accurate radiation dose to the target in MRgART, even though it is a time-consuming method.

• 한국산림과학회지
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• 제96권1호
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• pp.7-13
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• 2007

본 연구는 산림에서 개인휴대 단말기(PDA)를 기반으로 수치지형도와 GPS를 활용하여 산림지리정보를 활용할 수 있는 소프트웨어를 개발하는데 그 목적이 있다. 본 연구에서 개발한 산림지리정보 소프트웨어의 주요 내용과 그 특징은 다음과 같다. 산림지리정보검색 소프트웨어는 PocketPC 2002/2003 운영체계에서 작동하도록 하였다. PDA의 표시 화면은 DXF형식의 1:25,000 수치지형도를 PC에서 변환하여 활용하며, PDA에 표시하는 지도데이터는 1:2,500에서 1:30,000까지 5단계로 확대, 축소 표시가 가능하도록 제작하였다. GPS에서 수신한 위치정보 및 이동 경로정보를 화면에 나타내고 저장할 수 있도록 하였다. DXF형식의 수치지형도의 레이어 중 선택한 정보를 본 시스템에서 활용이 가능한 이진파일 형식으로 변환하는 소프트웨어를 제작하였다. 이를 활용하여 DXF 파일 크기 대비 90%이상 압축이 가능하였고, PDA의 처리 속도를 크게 향상시켰다. 산림지리정보검색 소프트웨어는 sub menu 기능과 grid index를 활용하여 GPS에서 수신된 위치정보와 함께 산림조사 자료입력 소프트웨어와 연동하여 표본점의 관리에 활용이 가능하도록 하였다. 산림작업자가 현장에서 필요한 임상, 소유, 위치, 임도, 사방댐, 시설물 설계도 등 산림지리정보를 현장에서 즉시 검색이 가능하도록 하였다. 산림지리정보검색 소프트웨어는 지리정보 표시기능과 정보검색기능을 이용하여, 일반인들의 등산, 관광, 유적지 답사 등에 현재 위치 및 이동 경로에 관한 정보를 제공할 수 있도록 제작하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.37-42
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• 1997

Off-line feed rate scheduling is an advanced methodology to automatically determine optimum feed rates for the optimization of NC code. However, the present feed rate scheduling systems have lim~tations to generate the optimized NC codes because they use the material removal rate or non-generalized cutting force model. In this paper, a feed rate scheduling system based on an improved cutting force model that can predrct cutting forces exactly in general machining was presented. Original blocks of NC code were divided to small ones with the modified feed rates to adjust the peak value of cutting forces to a constant vale. The characteristic of acceleration and deceleration for a given machrne tool was considered when off-line feed rate scheduhng was performed. Software for the NC code optimization was developed and applied to pocket machining simulation.

• 대한안전경영과학회지
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• 제4권1호
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• pp.69-80
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• 2002

최근 컴퓨터 기술의 발전과 함께 Mobile 컴퓨터 환경도 함께 급속히 발전하고 있다. 이로 인해 오프라인 컴퓨팅 및 네트워킹을 이용하던 사용자들이 Mobile 컴퓨팅 환경을 자주 이용하게 되고, Mobile 솔루션에 대한 사용자의 요구도 다양화되고 있는 추세이다. 이 중 Mobile 지도 서비스는 휴대하기 편한 Pocket PC라고도 불리는 PDA(Personal Digital Assistants)는 자신의 현재 위치를 확인할 수 있는 GPS(Global Positioning System)가 급속도로 보급됨으로써 Mobile 환경에서 가장 활용도가 높은 서비스로 부각되고 있다. 가까운 미래의 IT기술은 GPS와 PDA 등을 연계한 e포지션의 폭발적인 이용 증대와 국내 원천기술에 의한 세계적인 사업모델의 탄생이 눈앞에 현실로 다가오고 있다는 점을 감안하면, GPS를 활용한 Mobile 기술력 확보는 국가적 차원에서 대단히 중요하다는 견지를 같이하는 전문가들이 많다. 이러한 시대적 요구 환경 하에서, 본 논문에서는 JAVA VM 기반의 무선위치추적 제어미들웨어와 GIS 프로그램(Vector MAP Viewer)을 구축함으로써 APTS의 효율성에 관한 연구를 제안하고, 앞으로의 향후 개선방향을 제시하고자 한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (B)
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• pp.136-138
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• 2006

최근 이동통신 기술의 급격한 발전과 PPC(Pocket PC), 노트북 등의 휴대단말기의 보급 확산에 따라 위치기반 서비스(Location Based Service: LBS)가 주요한 응용분야고 부상하고 있다. 위치 정보에 대한 정확한 위치 추적 및 활용 방안에 대한 활발한 연구가 진행되고 있지만, 대부분 제공되는 서비스는 현재 사용자의 위치에 기반한 정적인 서비스를 제공하는 초보적인 단계에 있다. 이동경로는 사용자의 성향이나 상태를 반영하기 때문에 사용자의 이동패턴을 예측하거나, 사용자의 현재 상태를 추론하는데 도움을 줄 수 있다. 본 논문에서는 이동패턴에 따른 사용자의 의도를 예측하여 개별화 된 서비스 제공을 위해, RSOM(Recurrent Self Organizing Map)과 마르코프 모델을 단계적으로 구성하여 사용자의 이동패턴을 모델링하는 방법을 제안한다. 실제 연세대학교 캠퍼스 내에서 실제 대학원생의 생활을 모델로 GPS(Global Positioning System) 데이터를 수집하여. 이동패턴을 모델링하고 개별화된 서비스를 제공함으로써 제안하는 방법의 유용성을 검증하였다.