• 대한전자공학회논문지
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• 제21권6호
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• pp.85-93
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• 1984

본 논문에서는 gate array LSI의 Layout 설계중 새로운 초기 배치 알고리즘을 제안하고 있다. 인간에 의해 작성된 게이트 레벨 논리설계도면상에 모듈의 상대적 위치를 정해진 칩의 셀에 최대한 반영하여 배치할 수 있는 목적함수를 설정하고 그 함수에 의해 초기 배치를 구하였다. 제안한 방법의 유용성을 보이기 위해 이미 사용되고 있는 cluster성장법과 program 실험을 통해 최대 cut 수 및 총배선장을 비교하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.339-342
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• 2004

In this paper, we investigated methods to reduce SAR(Specific Absorption Rate) value with EMI(Electromagnetic Interference) paint distribution on front case of mobile handset. Simulations for several different EMI patterns were carried out. For the purpose of modeling, we used 3 dimensional CAD(Computer Aided Design) program, `Pro-engineering'. SAR simulation was done with SEMCAD, simulation platform for electromagnetic compatibility antenna design and dosimetry. In order to distinguish the individual pieces and to enable an assignment of the different material properties, each subfile was imported separately. In simulation, folding angle was set to $142^{\circ}.$ If we vary folding angle, different SAR value will be obtained. Among the tested EMI paint patterns, the hairpin pattern showed the best performance, i.e. the decrease efficiency of $16.5\%$ and horizontal-direction zigzag pattern showed the decrease efficiency of $12.2\%$ when we set the completely removed pattern as reference.

• 대한인간공학회지
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• 제12권1호
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• pp.17-24
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• 1993

Today, rapid development and timeliness of introducing a new product be- comes a more influencing factor of determing its competitive power due to a shortened product cycle, while rapid improvement of manufacturing technology makes product design and manufacturing fuse together. This implies that prod- uct usability evaluation and improvement starts right from its design phase, resulting in less development time and cost. To make this possible, proper as- sessment of human reach is one of essential functions for ergonomic product us- ability evaluation, specifically in the platform of computer-aided ergonomic evaluation models or any CAD system with a built-in man model. In this study, an analytic reach prediction algorithm ensuring the posture that human naturally takes, is presented by employing the methods developed for robot kinematics. Among robot kinematic methods for solving the multi-link system, the resolved motion method was found to be effective to solve human reach as a redundant manipulator model. Also, the joint range availability was used as a performance fonction to guarantee human naturalness. The result is expected to be directly applicable to product usability evaluations.

• E2M - 전기 전자와 첨단 소재
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• 제8권5호
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• pp.648-657
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• 1995

정보처리의 다양화, 고속화를 위하여 장래의 집적회로는 다량의 정보를 단시간에 처리하지 않으면 안된다. 종래, 3년에 4배의 고집적화가 실현되어 LSI개발에 기술 견인차의 역할을 하고 있는 DRAM(Dynamic Random Access Memory)은 미세화기술의 한계를 우려하면서도 오히려 개발에 박차를 가하고 있다. 이러한 DRAM의 미세, 대용량화에는 미세가공 기술, 새로운 메모리 셀과 트랜지스터 기술, 새로운 회로 기술, 그 이외에 재료박막기술, Computer aided design/Design automation(CAD/DA) 기술, 검사평가기술 혹은 소형팩키지(package)기술등의 광범위한 기술발전이 뒷받침되어 왔다. 그 중에서 미세가공 기술 및 새로운 트랜지스터 기술과 메모리 셀 기술을 중심으로 개발 동향을 살펴보고 최근에 발표된 1Gbit DRAM의 시제품 기술에 대하여 분석해 보기로 한다.

• 한국정밀공학회지
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• 제14권2호
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• pp.48-57
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• 1997

A computer aided analysis and design system is developed for analyzing the driveline torsional vibration of a vehicle. Torsional vibration characteristics of driveline component are investigated and 10 types of module are developed. They can be connected together to represent any driveline configuration. During assembly process simulation program is generated. It is implemented using C++language. A driveline tor- sional vibration system at full load driving condition and idle rattle system are modeled and simulated with this system. Their responses for engine torque excitation are evaluated on time and frequency domain, and the results are compared with test results favorably. This system makes it simpler and easier for design and analysis engineer to model and analyse the driveline system.

• 대한기계학회논문집
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• 제14권1호
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• pp.72-78
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• 1990

본 연구에서는 기존의 설계 시스템들이 갖지 못한 완전한 삼차원적 모델의 주 형을 생성할 수 있으므로 응축 시뮬레이션, NC공구 경로 생성등의 응용 프로그램과 직 접적으로 연결될 수 있는 장점을 갖고 있다. 본 논문의 1편에서는 위의 설계과정중 목형과 압탕부의 설계에 대해서 기술하고 탕구계와 주형의 설계에 대해서는 2편에서 기술하도록 한다.

• The Journal of Advanced Prosthodontics
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• 제14권1호
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• pp.12-21
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• 2022

PURPOSE. The purpose of this study was to investigate changes in retention and wear pattern of Locator^® and ADD-TOC attachments on a digital milled bar by performing chewing simulation and repeated insertion/removal of prostheses in fully edentulous models. MATERIALS AND METHODS. Locator (Locator^®; Zest Anchors Inc., Escondido, CA, USA) was selected as the control group and ADD-TOC (ADD-TOC; PNUAdd Co., Ltd., Busan, Republic of Korea) as the experimental group. A CAD-CAM milled bar was mounted on a master model and 3 threaded holes for connecting a bar attachment was formed using a tap. Locator and ADD-TOC attachments were then attached to the milled bar. Simulated mastication and repeated insertion/removal were performed over 400,000 cyclic loadings and 1,080 insertions/removals, respectively. Wear patterns on deformed attachment were investigated by field emission scanning electron microscopy. RESULTS. For the ADD-TOC attachments, chewing simulation and repeated insertion/removal resulted in a mean initial retentive force of 24.43 ± 4.89 N, which were significantly lower than that of the Locator attachment, 34.33 ± 8.25 N (P < .05). Amounts of retention loss relative to baseline for the Locator and ADD-TOC attachments were 21.74 ± 7.07 and 8.98 ± 5.76 N (P < .05). CONCLUSION. CAD-CAM milled bar with the ADD-TOC attachment had a lower initial retentive force than the Locator attachment. However, the ADD-TOC attachment might be suitable for long-term use as it showed less deformation and had a higher retentive force after simulated mastication and insertion/removal repetitions.

• 치위생과학회지
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• 제15권1호
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• pp.54-59
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• 2015

본 연구는 시중에 널리 사용되는 치과용 지르코니아 코어를 이용하여 서로 다른 형태의 지대치를 대상으로 작업모형을 제작한 후, 치과용 스캐너를 통해 3차원 디지털 모형을 전환한 데이터를 토대로 지르코니아 코어를 제작하였으며, 각 실험군별 변연 적합도를 측정하여 비교분석하고자 하였다. 이와 같은 결과로 형태가 다른 지대치가 CAD/CAM system으로 치과 보철물 제작 시 적합도의 영향여부를 비교하였다. 제한된 조건 하에서 수행된 본 연구에서 다름과 같은 결과를 보였다. 지대치의 형태가 다른 작업모형으로 제작된 지르코니아 코어의 변연 적합도는 큰 차이가 없었다(p>0.05). 작업모형의 부위를 4등분으로 나누어 측정한 변연 적합도 또한 통계적으로 유의한 차이를 보이지 않았다. 결론적으로 3종류의 다른 지대치 모두 유사한 지르코니아 코어의 변연 적합도를 보였으며, 측정된 결과는 선행연구에 비추어 볼 때 임상적으로 허용 가능한 수치($100{\sim}120{\mu}m$)를 초과하는 실험군은 없었다. 이와 같은 결과를 토대로 다른 형태의 지대치를 사용하여 제작되었더라도 지르코니아 코어의 변연 적합도에 큰 영향을 주지 않을 것으로 생각된다.

• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.120-127
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• 2019

PURPOSE. To determine wear amount of single molar crowns, made from four different restoratives, and opposing natural teeth through computerized fabrication techniques using 3D image alignment. MATERIALS AND METHODS. A total of 24 single crowns (N = 24 patients, age range: 18 - 50) were made from lithium disilicate (IPS E-max CAD), lithium silicate and zirconia based (Vita Suprinity CAD), resin matrix ceramic material (Cerasmart, GC), and dual matrix (Vita Enamic CAD) blocks. After digital impressions (Cerec 3D Bluecam, DentsplySirona), the crowns were designed and manufactured (Cerec 3, DentsplySirona). A dualcuring resin cement was used for cementation (Variolink Esthetic DC, Ivoclar). Then, measurement and recording of crowns and the opposing enamel surfaces with the intraoral scanner were made as well as at the third and sixth month follow-ups. All measurements were superimposed with a software (David-Laserscanner, V3.10.4). Volume loss due to wear was calculated from baseline to follow-up periods with Siemens Unigraphics NX 10 software. Statistical analysis was accomplished by Repeated Measures for ANOVA (SPSS 21) at = .05 significance level. RESULTS. After 6 months, insignificant differences of the glass matrix and resin matrix materials for restoration/enamel wear were observed (P>.05). While there were no significant differences between the glass matrix groups (P>.05), significant differences between the resin matrix group materials (P<.05) were obtained. Although Cerasmart and Enamic were both resin matrix based, they exhibited different wear characteristics. CONCLUSION. Glass matrix materials showed less wear both on their own and opposing enamel surfaces than resin matrix ceramic materials.

• 한국정밀공학회지
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• 제22권2호
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• pp.126-132
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• 2005

In this paper, an auto-design system is introduced for a stamping tool based on commercial computer aided design system with its drafting language. The auto-design system consists of tool oriented product design subsystem which modifies and configures the product drawing, tool concept design subsystem which make a design of the punches and their punching progression and parts design subsystem that makes automatic dimension. The system is applied to the mechanical design of the stamping tool. The main logic of the system is based on half-edge theory, a kernel for the 3 dimensional CAD system, which is applied to 2 dimensional drafting auto-design system. The auto-design system enables to conspicuously reducing the designing time of the tool. In addition, there is little drafting error that had been about 3% without auto design program. It is effective to reduce the development time for new products because of rapid designing time of the tools, standardization of the stamping tool and the drafting rule for the auto-design system. The auto-design system yields high efficiency of the tool manufacturing system.