• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.555-556
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• 2006

In recent years, the higher flatness level in wafer shape has been strictly demanded with a high integration of the semiconductor devices. It has become difficult for a conventional wafer preparing process to satisfy those demands. In order to meet those demands, surface grinding with in-feed grinder is adopted. In an in-feed grinding method, a chuck table fur fixing a semiconductor wafrr rotates on its rotation axis with a slight tilt angle to the rotation axis of a cup shaped grinding wheel and the grinding wheel in rotation moves down to grind the wafer. So, stability of the grinder structure is very important to aquire a wafer of good quality. This paper describes the features of the in-feed grinder and some FEM analysis results of the grinder structure.

• 한국정밀공학회지
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• 제27권7호
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• pp.94-100
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• 2010

This paper describes the design and evaluation procedure of an ultra-precision rotary table for freeform generating machined tools. Design of the thrust and journal hydrostatic bearings and experimental evaluation of the table were performed. To get the compact size and less lost motion direct drive servomotor with ultra precision encoder. From the considered design, following performance were confirmed by experiment. The total stiffness of the prototype rotary table was 483.6 $N/{\mu}m$ and 97.6 $N/{\mu}m$ for axial and radial direction, respectively. Rotational accuracy of the table was investigated by capacitive sensor and reversal measurement technique, and 0.10 ${\mu}m$ radial direction and 0.05 ${\mu}m$ axial direction of the rotational accuracy were confirmed. The micro resolution of the table was also investigated with displacement of capacitive sensor, and $0.5/10000^{\circ}$ of micro resolution was confirmed. Index accuracy of the table was evaluated by the autocollimator and polygon mirror, and the $\pm0.39$ arcsec accuracy and $\pm0.16$ arcsec repeatability of the table were confirmed. Those are under the general requirements of ultra precision rotary tables for freeform generating machined tools.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.82-91
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• 2017

Liquid alloy systems have a high degree of thermal conductivity, far superior to ordinary nonmetallic liquids and inherent high densities and electrical conductivities. This results in the use of these materials for specific heat conducting and dissipation applications for the nuclear and space sectors. Uniquely, they can be used to conduct heat and electricity between nonmetallic and metallic surfaces. The motion of liquid metals in strong magnetic fields generally induces electric currents, which, while interacting with the magnetic field, produce electromagnetic forces. Electromagnetic pumps exploit the fact that liquid metals are conducting fluids capable of carrying currents, which is a source of electromagnetic fields useful for pumping and diagnostics. The coupling between the electromagnetics and thermo-fluid mechanical phenomena and the determination of its geometry and electrical configuration, gives rise to complex engineering magnetohydrodynamics problems. The development of tools to model, characterize, design, and build liquid metal thermomagnetic systems for space, nuclear, and industrial applications are of primordial importance and represent a cross-cutting technology that can provide unique design and development capabilities as well as a better understanding of the physics behind the magneto-hydrodynamics of liquid metals. First studies for the development of computational tools for the design of liquid metal electromagnetic pumps are discussed.

• 산업경영시스템학회지
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• 제34권2호
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• pp.19-29
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• 2011

The uncertainty of a project generates risks hindering the goal achievement of the project, and the risks affect the success or failure of the project significantly. Risk management, a part of the project management, includes various processes, and there are also various tools or techniques applicable to that. In an organization, the application of project management develops gradually from low to high maturity, and the organization should choose and implement a method of application proper for the level of its maturity. This article suggests a method to reduce inefficiency of the management and how to apply risk management by levels of maturity for easier application. For this, the stages of project management maturity levels were divided into the introduction, development, and maturity step, and methods of risk management suitable for each stage were applied. And methods of risk management that need to be applied by the levels of project maturity are divided into three factors : risk management processes, risk management tools and techniques, and risk management standards and templates. It is expected to be favorable approaches for the application of risk management in an organization to divide those factors into more concrete processes, tools, techniques, and standards and apply them by the levels of management maturity.

• 실천공학교육논문지
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• 제12권2호
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• pp.301-308
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• 2020

근래 다문화가족의 급증 및 코로나-19로 인한 원격수업 등 비대면교육의 지속으로 초등 저학년의 교육격차가 발생하고 있다는 우려가 있다. 특히, 초등 저학년에서는 우리 말을 읽고, 쓰고, 듣고, 말하는 능력이 정착이 되어야 한다는 점에서 중요성이 부각되고 있다. 따라서 이 연구에서는 최근 관심도가 높은 인공지능 도구를 활용함으로써 이해도를 높이고, 놀이를 통하여 흥미롭게 한글교육을 할 수 있는 콘텐츠를 개발하였다. 앞으로 인공지능 도구들이 초등 저학년 교과교육에서 활용할 수 있는 다양한 시도가 필요하다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.206-217
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• 2007

Generally, there is confusion as to what constitutes TQM, though it can be regarded as a set of concepts and tools for getting all employees focused on continuous improvement, various schools of thought have defined or classified the critical success factors as constructs, concepts and principles. Therefore the main aim of this paper is to provide a practical approach for understanding the quality management terminology. Using the existing quality management measurement instruments available in literature, the terminology used is classified into constructs, practices and finally tools or techniques. Quality Management may then be viewed as a combination of the three sets of terminology. Drawing on the quantitative study which investigated the implementation of TQM within the SME, the critical factors of TQM as used in that study as used to demonstrate the practical approach or methodology for the understanding of the terms thus used. For the benefit of practitioners within the Construction Management field, a bit of clarity is required as regards the terminology used. This study contributes to clarifying the conflicting results being reported in the quality management literature which inevitably leads to having different levels of analysis of Quality Management. Accordingly, the strength of quality management compared with other business philosophies should then focus on the practical methodology, namely the practices and techniques.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.271-271
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• 2020

GIS-Based Disaster Prevention Engineering Tools(이하 GDP Tools)는 수자원·방재 관련 설계 편의를 위해 개발된 도구로 직관적인 사용자 편의 인터페이스(GUI)를 바탕으로 한 독립실행형 응용프로그램이다. GDP Tools의 기능은 다음과 같이 세 가지로 구분할 수 있다. 1) GIS 관련 기능: 지오코드, 지도 관리, 래스터/벡터 파일 관리 등 2) 재해 발생가능성 분석 기능: 하천·내수·사면·토사·바람·가뭄·대설재해 등 자연재해저감종합계획에서 다루는 재해유형별 전지역단위 분석, 지형분석 3) 기타 기능: 현장조사표 작성, 저감대책의 개략사업비 산정, 각종 파일 관리, 기초통계 및 수문분석 등 GDP Tools는 실무에서 자주 사용되는 GIS 기능은 물론 각종 재해유형별 자연재해 발생가능성 분석, 지형분석 등 각종 편의 기능을 제공하고 있어서 수자원·방재 과업을 일괄적으로 진행할 수 있다. 여러 수치모형을 종합적으로 사용하는 기존 방법과 달리 별도로 자료 전·후처리 과정이 필요 없으며, 과업에 필요한 기본 자료가 전국 단위로 구축·준비되어 있어 사용자가 따로 준비해야할 사항을 최소화한다는 장점이 있다. 본 논문에서는 GDP Tools의 개발 내용과 세부 기능, 적용사례를 소개하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.809-810
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.960-963
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• 2002

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

• Tribology and Lubricants
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• 제13권1호
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• pp.8-13
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• 1997

Generally, A motor integrated spindle is selected to perform the high speed machining, to improve the machining flexibility, and to simplify the structure of machine tools. The thermal deformation caused by heat generation of the integrated motor is, however, serious problem in motor integrated spindle system. In this study, cooling characteristics for the several kinds of cooling systems(such as, oil-jacket cooling, air cooling) are investigated and more efficient cooling method is presented. The results show that the shaft cooling by the air cooling system is effective to improve the thermal characteristic of motor integrated spindle.