• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.111-115
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• 2001

The die design for hot forging was investigated for manufacturing precisely of scroll rotor made with Al-Si alloy. A scroll rotor is a non-symmetric 3-D shape part, having involute wraps. Disk-shaped billet of Al-Si alloy was extruded to wraps and boss simultaneously. Because the involute wraps is not axi-symmetric, the flow velocity and the stress of die is very much different at each portion. Moreover, the die in wraps portion is a cantilever beam and fractured. In this paper, the analysis of forming and die stress is investigated using the FEM tool, DEFORM-3D. The tensile strength of tool material is $250kg/mm^{2}$. From the analysis results, we can find the maximum principal stress of die is over the fracture strength and redesign the die. The prototype forged part is superior in net shaping and microstructure.

• Journal of Sensor Science and Technology
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• 제5권2호
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• pp.1-8
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• 1996

In this paper, We have designed silicon pressure sensor with center-bossed diaphragm which improving sensitivity and linearity by reducing diaphragm deflection. Designed center-bossed pressure sensor showed maximum deflection of $0.125{\mu}m$, maximum stress of $2.24{\times}10^7 Pa$ and sensitivity of 27.67 mV/V.psii. As a result, diaphragm deflection was reduced to 1/160 that of diaphragm thickness and 1/35 that of square diaphragm. Also, sensitivity was increased 19 times compared to square diaphragm.

• Tribology and Lubricants
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• 제23권3호
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• pp.95-102
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• 2007

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. Moreover, the lead removal from the bush material has strongly reduced the capability of the anti friction material to accept asperity contacts. In this paper, before trying to find the pressure distributions on the oil film of piston pin bearings by the unsteady two dimensional thermohydrodynamic lubrication analysis in order to do the optimum design of the bearings of piston pin, it will be investigated the tendancy of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress.

• Journal of the Korean Society for Precision Engineering
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• 제17권6호
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• pp.176-184
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• 2000

Reverse engineering (RE) is a process to create computer aided design (CAD) models from the scanned data of an existing part acquired using 3D position scanners. This paper proposes a novel methodology of extracting geometric features directly from a set of 3D scanned points, which utilizes the concepts of feature-based technology and artificial neural networks (ANNs). The use of ANN has enabled the development of a flexible feature-based RE application that can be trained to deal with various features. The following four main tasks were mainly investigated and implemented: (1) Data reduction; (2) edge detection; (3) ANN-based feature recognition; (4) feature extraction. This approach was validated with a variety of real industrial components. The test results show that the developed feature-based RE application proved to be suitable for reconstructing prismatic features such as block, pocket, step, slot, hole, and boss, which are very common and crucial in mechanical engineering products.

• Journal of the Korean Society for Precision Engineering
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• 제18권8호
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• pp.164-173
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• 2001

The configuration of injection molded part can be classified into primary feature and supplementary feature. Even though supplementary features such as ribs, snap fits and bosses make mold more complicated, which cause the increasement of the mold cost, supplementary features should be attached to primary features because of assembly, reinforcement, moldability and other functional purposes. But it is not easy for novice designers to design them appropriately because of the profound knowledge related to Injection molding. In this paper, the intelligent design tool called ISFD(Intelligent Supplementary Feature Designer) which supplies easy, simple, time and cost-effective design method has been studied and developed. A knowledge-based design system is a new tool which enables the concurrent design and CIM with integrated and balanced design decisions at the initial design stage of injection molding.

• Proceedings of the Korea Information Processing Society Conference
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.1024-1026
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• 2017

인트라 블록과 인터 블록의 상관계수를 이용하여 이미지의 특징을 뽑아내고, 이를 SVM에 학습시켜 원본과 스테고 영상을 판별한다. 스테고 영상은 F3 알고리즘을 개선한 F4알고리즘을 직접 구현하여 만들어냈다. 실험에 사용한 데이터는 SIPI, BOSS, 자체 수집 데이터베이스에서 학습용 영상 120장, 테스트용 영상 500장을 이용하였다. 원본 500장에 대해 2장이 F4로 판별 되었고, F4 500장에 대해서는 전부 F4로 판별하여 99.8%의 정확도를 달성하였다.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (3)
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• pp.280-282
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• 2004

본 논문은 현재 서비스 발견(SoNics Discovery) 기술로서 각광을 받고 있는 UPnP(Universal Plug and Play)기반의 서비스 활용 및 관리 기능을 적용하기 위한 센서 네트워크 구조를 제안한다. 이를 통해 센서 네트워크 사용자는 수동적인 설정 없이 센서 노드들을 바로 설치 할 수 있으며, 또한 각 센서들이 제공하는 서비스 및 센서 네트워크 전반에 사용될 수 있는 서비스(가령, 컨텍스트 정의 및 활용, 센서 위치 추적, 동기화, 전원 관리 등)를 쉽게 이용할 수 있고, 또한 이하 센서 네트워크 관리도 원활히 할 수 있게 된다. 그러나 TCP/IP 기반에서 동작하는 UPnP는 초소형의 센서 노드에는 적합지 않다. 이에 본 논문에서는 UPnP에 적합하지 않는 초소형의 센서 노드를 위한 브리지 역할 뿐만 아니라, 센서 네트워크 전반의 관리 서비스를 제공하는 BOSS(Brdige Of Sensors)라는 구조를 제안한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 한국경영과학회 2006년도 추계학술대회
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• pp.211-231
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• 2006

This study integrated the factors for enterprise-wide IS implementation and BPMS-specific factors to examine factors for effective BPMS implementation. We interviewed IT-consultants and CIOs who conducted BPMS projects. As a result, monitoring function has been agreed as a main BPMS-specific factor. We reviewed literature on BPMS implementation and Computer-based monitoring and integrated the factors from the literature with TAM. We used structural equation modeling to test hypotheses and found some organizational factors such as reward management, boss' fairness were significant.

• Journal of the Korean Society for Railway
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• 제10권6호
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• pp.792-799
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• 2007

The purpose of this article is to depict the relationship between the frames of leadership and the dependent variables such as job satisfaction, respect from subordinates, and promotion speed of boss. To attain this purpose, for types of multiple leadership frames, such as structural, human resources, political, and symbolic frames were surveyed through questionnaire and analyzed by SPSS.

• Journal of Sericultural and Entomological Science
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• 제17권2호
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• pp.171-173
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• 1975

This experiment was conducted to study the reasonable deguming method of cocoon on the Boss silk making. The results obtained are as follows： 1. Reasonable deguming method of cocoon on the floss silk making was observed to be about 0.75％ Na$_2$SiO$_3$, 2％ NaCO$_3$ solution during 40 minutes boiling Process. 2. Treatment 6 increased qualities of floss silk and hand spun silk as compared with the other conventional method.