• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 추계학술대회 논문집
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• pp.60-63
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• 1995

The behavior of the work materials in the chip-tool interface in extremely high strain rates and temperatures is more that of viscous liquids than that of normal solid metals. In these circumstances the principles of fluid mechanics can be invoked to describe the metal flow in the neighborhood of the cutting edge. In the present paper an Eulerian finite element model is presented that simulates metal flow in the vicinity of the cutting edge when machining a low carbon steel with carbide cutting tool. The work material is assumed to obey visco-plastic (Bingham solid) constitutive law and Von Mises criterion. Heat generation is included in the model, assuming adiabatic conditions within each element. the mechanical and thermal properties of the work material are accepted to vary with the temperature. The model is based on the virtual work-stream function formulation, emphasis is given on analyzing the formation of the stagnant metal zone ahead of the cutting edge. The model predicts flow field characteristics such as material velocity effective stress and strain-rate distributions as well as built-up layer configuration

• 공학교육연구
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• 제17권4호
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• pp.48-53
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• 2014

Recently, the tendency for young people losing interest in science has accelerated. This tendency is remarkable for not only Japan but also some countries of Asia. It is thought that this tendency was brought from the decrease of the chance to watch the actual manufacturing activities, and the decrease of the real experience which children makes something in their childhood. In order to bring up the capable engineers on such a social background, making a product practice which promotes the understanding of the application of theory for manufacturing products is important in addition to study by the text book. In this study, some practical work materials for the lower grades in the college were developed. Integration of the developed materials and the course of study becomes an effective teaching method of the of subjects on a special field. Arranging this practical work on the learning process makes a high effect of the integrated practical work on the curriculum.

• 한국중재학회지:중재연구
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• 제23권4호
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• pp.169-189
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• 2013

Organizations have traditionally been established and managed by men. As more women enter organizations, a new kind of conflict occurs at work owing to differences between men and women. Conflict can generate positive outcomes if managed properly; thus, this study outlines the causes of creating conflicts between men and women and considers whether ADR is applicable and useful at work. As ADR offers a means of bringing workplace justice at lower cost and with speed, it can serve as an effective way of resolving conflicts between men and women at work. In order to use ADR as a method of resolving conflict between men and women, I suggest reinforcing the function of a grievance committee in a company and cultivating an ADR specialist.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.9-13
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• 2009

As recent construction projects are bigger and higher, the importance of lifting is increasing. In construction sites tower cranes are an essential lifting equipment covering were than 50% of all construction activities. But due to neglect of safety supervision, tower crane-related accidents are frequently taking place. Since most of construction activities is done in heights, the accidents are more likely to be catastrophic. According to an analysis of the causes of tower crane-related accidents, 49% of all accidents claimed for certain periods($1999{\sim}2003$) occurred in the process of telescoping work. Therefore, this research is conducted with the object of analyzing telescoping work of tower cranes and presenting solutions against safety risk. It is expected that the results of this study can be used as useful basic data or material when preparing for effective safety management for tower cranes.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권4호
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• pp.208-212
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• 2004

In this paper, the characteristics of co-sputtered Ru-Zr metal alloy as gate electrode of MOS capacitors have been investigated. The atomic compositions of alloy were varied by using the combinations of relative sputtering power of Ru and .Zr. C-V and I-Vcharacteristics of MOS capacitors were measured to find the effective oxide thickness and work function. The alloy made of about 50% of Ru and 50% of Zr exhibited an adequate work function for nMOS. C-V and I-V measurements after 600 and $700^{\circ}C$ rapid thermal annealing were performed to prove the thermal and chemical stability of the Ru-Zr alloy film. Negligible changes in the accumulated capacitance and work function before and after annealing were observed. Sheet resistance of Ru-Zr alloy was lower than that of poly-silicon. It can be concluded that the Ru-Zr alloy can be a possible substitute for the poly-silicon used as a gate of nMOS.

• Safety and Health at Work
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• 제7권1호
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• pp.83-85
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• 2016

Effective interventions to reduce work-related exposures are available for many types of work-related diseases or injuries. However, knowledge of the impact of these interventions on injury or disease outcomes is scarce due to practical and methodological reasons. Study designs are considered for the evaluation of occupational health interventions on occupational disease or injury. Latency and frequency of occurrence of the health outcomes are two important features when designing an evaluation study with occupational disease or occupational injury as an outcome measure. Controlled evaluation studies-giving strong indications for an intervention effect-seem more suitable for more frequently occurring injuries or diseases. Uncontrolled evaluation time or case series studies are an option for evaluating less frequently occurring injuries or diseases. Interrupted time series offer alternatives to experimental randomized controlled trials to give an insight into the effectiveness of preventive actions in the work setting to decision and policy makers.

• 한국산업보건학회지
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• 제22권1호
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• pp.1-8
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• 2012

Objectives: The aim of this study is to review occupational hygiene activities, including work environment measurement as required by the industrial safety and health laws of Korea, and suggest improvements required to establish an effective exposure surveillance system. Methods: The controversial limitations of exposure surveillance examining the work-association of several types of cancers in semiconductor workers were reviewed. Results: The bulk of the exposure surveillance system was found to focus purely on work environment measurements without providing other important exposure surrogates, such as job title, operation, exposure duration, etc. The current work environment measurement system is limited in terms of the efficient assessment of the exposure status of workers due to a lack of exposure information. Conclusion: The introduction of a national standard classification of occupations and job titles into the exposure and health effect surveillance system should be discussed in order to retrospectively assess exposure characteristics.

• International Journal of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.29-35
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• 2024

TCP is considered as one of the major candidate transport protocols even for constrained IoT networks..In our previous work, we investigated the congestion control mechanism of the uIP TCP. Since the uIP TCP sets the window size to one segment by default, managing the retransmission timer is the primary approach to congestion control. However, the original uIP TCP sets the retransmission timer based on the fixed RTO, it performs poorly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe. In our previous work, we proposed a TCP retransmission timer adjustment scheme for uIP TCP which adopts the notion of weak RTT estimation of CoCoA, exponential backoffs with variable limits, and dithering. Although our previous work showed that the proposed retransmission timer adjustment scheme can improve performance, we observe that the scheme often causes a node to set the retransmission timer for an excessively too long time period. In this work, we show that slightly modifying the dithering mechanism of the previous scheme is effective for improving TCP fairness.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.527-535
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• 2015

본 연구는 간호사들의 근무환경에 따른 직업적 손상 및 신체적, 정신적 건강상태를 비교분석하기 위해 실시되었다. 서울의 한 대학병원에 근무하는 192명의 간호사를 조사대상으로 하였다. 근무환경과 직업적 손상에 따른 건강상태의 각각의 범주를 분석한 결과 신체적, 정신적 건강에 의미있는 차이가 있음을 발견하였다. 교대근무는 고정근무에 비해 직업적 손상과 상당한 관련이 있었다. 또한 밤근무가 다른 근무형태에 비해 간호사들의 신체적, 정신적 건강에 부정적 영향을 미치고 있음이 확인되었다. 따라서 근무환경과 직업적 손상에 의한 그들의 건강상 문제를 고려하여 근무체계가 개발되어야 할 필요가 있다. 그리고 밤근무자들을 위한 추가적인 지원 및 효과적인 밤근무를 위한 연구를 해야 할 것이다.

• 한국건설관리학회논문집
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• 제8권5호
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• pp.80-91
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• 2007

최근 국내 외적으로 크랙실링 공법의 활용성을 높이기 위해 도로면 크랙실링 자동화 장비 개발에 관한 연구를 활발히 진행하고 있다. 예방적 차원에서 도로의 장 수명화 및 유지보수 비용 절감을 위해서는 도로 유지관리 시점 및 유지 보수된 구간정보, 작업 수행 결과 등과 같은 이력정보가 체계적으로 수집.축적될 수 있는 관리체계의 개발이 선행되어야 한다. 그러나 기존 크랙실링 관련 기술개발 동향은 크랙실링 공법의 자동화를 위한 연구가 주로 수행되고 있을 뿐 도로면 크랙실링 작업정보 수집과 관련한 연구는 미흡한 것으로 나타났다. 따라서 크랙실링 작업 관련 정보습득의 어려움 및 경영 분석과 성과측정을 위한 객관적인 자료 구축 미흡, 수집된 정보의 신뢰성 부족 등과 같은 문제점이 도출되었다. 본 연구에서는 크랙실링작업 시 발생되는 정보를 신속.정확하게 수집 및 축적하여 이력관리로 활용하고 작업 주체간의 정보교류를 효율적으로 수행할 수 있도록 지원하는 PDA 및 웹 기반 크랙실링 작업정보 수집 시스템을 제안하고자 한다.