• 한국정밀공학회지
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• 제10권2호
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• pp.114-125
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• 1993

In the present study the newly developed CAD/CAM system is applied to the process of the molding design, machining for mini-sized and precise processive die, and the production of press-stamped parts. When the design of a die was completed by means of CAD, wire cut NC data were generated with the aid of a design drawing in the CAD system and then inputed into the wire cut machine, and with the aid of a hole chart which had been made for this purpose, all the data were classified into the categories of CNC milling, jig boring, jig grinding, and machine center, and then developing a program of generating NC data, errors in process were reduced and programming time was shortened. The program was developed by using Autolisp language which was built-in the CAD, and realizing the intergation of designing a die, generating and processing NC data directly by a designer, designing time and machinery processing time were shorted. And the traditionally required working time for design. NC program required 6 days of work becomes 4 days of work by using the developed CAD/CAM system so that the efficiency shows 150% of the reduction working time. The prpgram of the design of the automation a progressive die mold was developed in the PC-Class Autocad system, therefore development expense could be reduced, and the integration of the CAD/CAM of the progressive die mold with the standard DB being built could be realized.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.422-425
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• 2003

건축공사의 고층화 추세에 따라 반복공정의 수가 증가하고, 마감공사에서의 관련 공종 수가 증가하여 작업 연속성에 대한 계획 및 공사관리가 중요하게 인식되고 있으며, 이러한 마감공사의 효율적 은용을 위해 각 작업을 일정한 리듬으로 반복되도록 함에 따라 공정의 개선을 이루고자 하는 기법이 택트공정관리이다. 그러나 택트공정관리는 세부공정 및 작업구역에 따른 상이한 시공속도와 이로 인한 선행공정의 작업지연 등 비효율적 요소 때문에 적용에 어려움이 있었다. 따라서 본 연구에서는 작업별 소요시간의 동기화(同期化)를 통한 개선효과를 파악하기 위해 기존의 공동주택 창호공사를 대상으로 작업방식의 세부작업단위 및 작업인원 수를 작업시간의 동기적(同期的)연결 및 최소 요구인원 수를 기준으로 조정한 후, 공기단축 효과를 분석하였다.

• Structural Monitoring and Maintenance
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• 제5권2호
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• pp.205-229
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• 2018

Energy induced by minor earthquake and micro vibration cannot be dissipated by traditional buckling-restrained braces (BRBs). To solve this problem, a new type of hybrid passive control device, named as VE-BRB, which is configured by a BRB with high-damping viscoelastic (VE) layers, is developed and studied. Theoretical analysis, performance tests, numerical simulation and case analysis are conducted to study the seismic behavior of VE-BRBs. The results indicate that the combination of hysteretic and damping devices lead to a multi-phased nature and good performance. VE-BRB's working state can be divided into three phases: before yielding of the steel core, VE layers provide sufficient damping ratio to mitigate minor vibrations; after yielding of the steel core, the steel's hysteretic deformations provide supplemental dissipative capacity for structures; after rupture of the steel core, VE layers are still able to work normally and provide multiple security assurance for structures. The simulation results agreed well with the experimental results, validating the finite element analysis method, constitutive models and the identified parameters. The comparison of the time history analysis on a 6-story frame with VE-BRBs and BRBs verified the advantages of VE-BRB for seismic protection of structures compared with traditional BRB. In general, VE-BRB had the potential to provide better control effect on structural displacement and shear in all stages than BRB as expected.

• 자원환경지질
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• 제31권3호
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• pp.265-271
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• 1998

In the hydrologic and hydrochemical studies of natural waters, oxygen and hydrogen isotope compositions of waters are very important to elucidate the origin and circulation pattern of water in the hydrologic system. The hydrogen isotope analysis of waters usually has been undertaken through the reduction of water to form hydrogen gas using pure metals (in general, zinc and uranium). In 1996, a new apparatus (H/Device) was developed to prepare the water samples (by the reduction with Cr metal) without some intrinsic problems that may yield incorrect and/or inaccurate data, and was installed at 1997 in the Center for Mineral Resources Research (CMR) in Korea University. However, the optimistic conditions of preparation and analysis of samples has not been established. In this paper, we introduce the efficiency of H/Device to obtain accurate hydrogen isotope values of water, and discuss both the optimum conditions including the effective reduction time and the probable mixing (memory) effect between successive samples. We obtained large amounts of a laboratory working standard (KUW; Korea University Water) with the average ${\delta}D_{SMOW}$ value of $-42.1{\pm}1.0$‰ $(1{\sigma})$.

• 보건행정학회지
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• 제32권4호
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• pp.368-379
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• 2022

Background: This study aimed to establish a strategy to improve the poor working environment and working conditions among long-term healthcare workers in Korea. Methods: A total of 600 questionnaires with which long-term health care workers participated in the targeted base areas of each city and province nationwide were distributed directly and 525 responses were collected and 506 responses were analyzed. Surveys, on-site field visits, and in-depth interviews were also conducted to understand the working environment as well as conditions and establish a strategy for improving the working environment among long-term healthcare workers to understand the demands of working conditions and working conditions. Results: Korean long-term care workers firstly and mostly enumerated their risk factors for ill-health when lifting or moving elderly recipients directly by hand (69.9%), followed by increased physical workload with old beds, tools, and facilities (42.3%) in the workplaces, shortage of manpower (32%), and source of infection (30%). To improve the working environment as well as conditions, Korean long-term care workers considered improving low-wage structures, ergonomic improvements to solve excessive physical loads, and increasing various bonus payments as well as implementing the salary system, positive social awareness, and increasing resting time. Of 506 responses, 92.3% replied that the long-term care insurance system for the elderly should be developed to expand publicization at the national level. Conclusion: This study proposes to improve the low-wage structure of Korean long-term care workers, automation and improvement of facilities, equipment, and tools to eliminate excessive physical loads (beneficiary elderly lifting), and reduction of night labor.

• 한국사회복지학
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• 제67권4호
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• pp.31-50
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• 2015

본 연구는 근로빈곤층 장애인가구의 빈곤의 양상과 빈곤탈출 요인을 동태적 관점에서 분석하였으며, 장애인고용패널조사(1~6차년도)를 분석자료로 사용하였다. 분석결과, 장애인가구의 근로빈곤율은 전체 근로빈곤율의 약 3배 정도 높은 수준이며, 장애인 근로빈곤층의 규모는 전체 장애인 빈곤층의 평균 21.4%를 차지해 근로빈곤은 장애인 빈곤의 주요한 형태로 나타났다. 그리고 전체 인구의 단기간의 빈곤탈출확률은 60%를 넘어서는데 비해 근로빈곤층 장애인가구는 54.6%에 그쳐 빈곤탈피가 어려운 것으로 나타났다. 또한, 경제활동요인은 장애인가구의 근로빈곤의 탈출에 영향을 미치는 주요 요인이나, 취업은 반드시 빈곤의 탈출로 귀결되지 않으며, 근로시간, 종사상 지위 등의 취업의 질이 빈곤탈출에 주요한 요인으로 나타났다. 이 같은 결과는 장애인 근로빈곤의 해소를 위해 장애인의 고용지속성 확보와 더 나은 일자리로의 상향이동 촉진, 장애친화적인 근무환경 조성 그리고 사회안전망 내실화가 필요하다는 점을 시사한다.

• 한국국방경영분석학회지
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• 제22권1호
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• pp.18-29
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• 1996

Nowadays, flooding wast is serious problem to mankind and the endeavour for solving waste problem is performed in connection with environmental problem and natural resource problem. In Korea, there are a lot of movements related to reduction of waste, too. As the solution of these problems, recycling is recommanded and many kinds of recycling technique are devised. In America, military has been playing an important role in recycling area for a long time. This paper is the survey of several articles and working papers about America military's recycling research. We investigated the recycling of water, construction and demolition wastes etc. These research results are very important in real field of military. It is considered our military has to prepare this recycling problem and now it's the right time. All of these can be adapted to our military, commercial companies and civilians through some modification. We suggest that our military should cope with recycling problem more deliberately.

• 한국세라믹학회지
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• 제34권11호
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• pp.1121-1128
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• 1997

In this study, the Ar plasma treatment was used to improve the surface roughness of Poly-Si1-xGex thin film deposited by RTCVD. The surface roughness and the resistivity of Si1-xGex thin film were investigated with variation of Ar plasma treatment parameters (electrode distance, working pressure, time, substrate temperature and R.F power). When the Ar plasma treatment was used, the cluster size decreased by the surface etching effect due to the increasing surface collision energy of particles (ion, neutral atom) in plasma under the conditions of decreasing electrode distance and increasing pressure, time, temperature, and R. F power. Although the surface roughness value decreased by the reduction of the cluster size due to surface etching effect, however, the resistivity increased. This may be due to the surface damage caused by the increasing surface collision energy. It was concluded that the surface roughness could be improved by the Ar plasma treatment, while the resistivity was increased by the surface damage on the substrate.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2019년도 정기학술대회 발표논문집
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• pp.83-83
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• 2019

Increasing the CO₂ concentration in the atmosphere induce high temperature and rising sea levels. So the technology that capture and reuse of the CO₂ have been recently become popular. Among other methods, CRR(CO2₂ reduction reaction) is typical method of CO₂ reusing. Electrocatalyst can show more higher efficiencies in CRR than photocatalyst because it doesn't use nature source. Nowadays, finding high efficient electrocatalyst by controlling electronic (affected by stoichiometry) and geometric (affected by atomic arrangement) factors are very important issues. Mono-atomic electro-catalyst has limitations on controlling binding energy because each intermediate has own binding energy range. So the Multi-metallic electro-catalyst is important to stabilize intermediate at the same time. Carbon monoxide(CO) which is our target product and important feedstock of useful products. Au is known for the most high CO production metal. With copper, Not only gold/copper has advantages which is they have FCC packing for easily forming solid solution regardless of stoichiometry but also presence of adsorbed CO on Cu promotes the desorption of CO on Au because of strong repulsion. And gold/copper bi-metal catalyst can show high catalytic activity(mass activity) although it has low selectivity relatively Gold. Actually, multi-metallic catalyst structure control method is limited in the solution method which is takes a lot of time. In here, we introduce CTS(carbo thermal shock) method which is using heat to make MMNP in a few seconds for making gold-copper system. This method is very simple and efficient in terms of time(very short reaction time and using carbon substrate as a direct working electrode) and increasing reaction sites(highly dispersed and mixing alloy structures). Last one is easy to control degree of mixing and it can induce 5 or more metals in one alloy system. Gold/copper by CTS can show higher catalytic activity depending on metal ratio which is altered easily by changing simple variables. The ultimate goals are making CO₂ test system by CTS which can check the selectivity depending on metal types in a very short time.

• 한국대기환경학회지
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• 제27권6호
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• pp.692-702
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• 2011

For more effective indoor radon reduction policy and technique, we researched radon data analysis for some buildings in Seoul. Those buildings were categorized as dwelling, underground and office space and the variations of radon concentration and its sources were evaluated. The variations of radon concentrations of indoor space of buildings for a day were patterned specifically by dwelling habits and different environment. As for the new built apartments which were not yet moved in, their indoor radon concentrations were showed more than 3 times after applying interior assembly, and were 5 times higher than ones of rather old residences. As for the subway stations, the radon concentrations during off-run times were about 15% higher than run-times. 10% of radon seemed to be reduced by installation of platform screen doors. As for office space, radon concentrations during working hours were about 2.5 times higher than non-working hours. Plaster board are expected as a main source of radon for them. By radon measurement method for long-term, its data can be over estimated because it covers non-active time in office or public space. Therefore combination of short and long-term measurement method is required for effective and economic reduction. Furthermore importance of ventilation is requested as public information service for all dwelling space. And also standardization for radium content or radiation of radon is necessary.