• 한국생활과학회지
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• 제15권4호
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• pp.675-689
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• 2006

The purpose of this study is to examine the actual conditions of kindergarten outdoor facilities in Korea, based on their establishment types and their located areas. The subjects for the survey were 6,819 kindergartens, and the subjects for sample-depth survey were the 10% of the total group, The study was conducted with an online survey and an on-the-spot survey, Spss 12.0 was used for statistics analysis, Most outdoor facilities of kindergartens in Korea consisted of playgrounds with soil or sand and complex playing equipments, The rate of Kindergartens' owning and utilizing their educational equipments was high. The educational utility of kindergarten outdoor facilities was high, too, but the needs of public kindergartens and that of private kindergartens were different. The 3% of private kindergartens had playgrounds on the roof, so they needed to be inspected periodically by the authorities. The kindergartens attached to the primary schools needed independent playgrounds of primary schools, Most kindergartens are required to explore diverse paving materials of their playgrounds and to develop outdoor equipments for childrens' creative playing.

• 대한조선학회논문집
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• 제54권6호
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• pp.447-452
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• 2017

A rigid body supported by 4 linear springs has been analyzed, to investigate the effects of eccentricities on the vibration responses for naval shipboard equipments supported by elastic mounts. Considering mount eccentricity (the location of the center of spring reaction forces relative to the mass center) and excitation force eccentricity (the location of the center of the excitation force relative to the mass center), the vibration phenomena have been formulated and discussed. Also, the effects of the eccentricities have been evaluated and discussed for the elastically mounted naval shipboard equipment. Results show that the mount eccentricity has little effects on the structure-borne noise above the natural frequency of the system, however the excitation force eccentricity has significant effects all over the frequency range.

• 한국인터넷방송통신학회논문지
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• 제13권2호
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• pp.269-273
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• 2013

본 논문은 대표적인 전파응용기기로 알려진 PDP(Plasma Display Panel) TV와 RF(Radio Frequency) 전구가 30MHz 이하 무선 서비스에 대한 전자기기의 잠재적 간섭 영향을 분석한 것이다. PDP TV와 RF 전구의 방사 크기를 전자파무반사실에서 측정하였고 이를 바탕으로 다수의 간섭 신호가 존재하는 경우에 결합된 간섭신호의 크기를 계산하였다. 분석 결과, 간섭원의 수에 따라 결합된 간섭 신호의 크기가 증가되는 경향을 확인하였다. 실험을 통해 얻어진 전자기기의 방사 측정값과 CISPR(International Special Committee on Radio Interference) 11의 제한치를 비교함으로 30MHz 이하의 무선 서비스에 대한 전자기기 간섭 잠재성을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1027-1036
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• 2007

Since the opening of the Seoul Metro in 1974, the electric railway passengers have been increased rapidly and as the advanced equipments(OC,PSD) were introduced, additional power facilities were built in a limited area for the comfortable transportation environment. Present grounding system were built according to old Electric equipment standards and all the electric signal, communication and electronic equipments were built only for the purposes of protecting building structure, people and electronic equipments. Grounding system which was additionally built in the limited area caused problems with the building structure and it caused secondary damages when earth fault happens. One of the problems is grounding system of the building structure; grounding system does not work properly since grounding equipments are not separated from each other. So, existing grounding system needs to be improved and unified grounding system in the building should be established. The purposed of this study is to analyze all the grounding systems that had been built in different year and to establish unified grounding system of Seoul Metro.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1864-1870
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• 2007

The inspection periods for the metro EMU maintenances vary variously according to the countries and railway operators. And the inspection systems vary according to the safety, economical, technical aspects, and also the social environments like passengers and maintenance qualities, etc. Also, in economic point of view, maintenance requires the man power, facilities, equipments, purchasing of parts and the loss of not being in revenue service during the maintenance period. Recently, there is a tendency that the inspection periods are extended gradually owing to the increased reliabilities of the equipments and parts of EMUs. Even if it is the EMUs that are already be in service, once the inspection method is innovated, the inspection time can be reduced. The inspection management innovation scheme includes such methods as the complete module to module replacement when trouble shooting a faulty parts before putting the EMU back to revenue service, the replacements of parts in complete set unit for the heavy maintenance, the establishments of exchange periods for the wasting parts, modernization of inspection equipments, introduction of RAMS for the reliability improvement and computerization of EMU maintenance management, etc. I think it is possible to optimize the inspection scopes and periods per parts and equipments by the introduction of RAMS.

• 한국안전학회지
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• 제26권2호
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• pp.26-31
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• 2011

In this paper, the safety diagnosis using thermal image analysis is described for power equipments. The conventional three-phase comparison method has only provided the results of thermal comparison for the equipments. The proposed method defines the conditions of poor connection by visual checks, and supports the criteria with each thermal rise step. As a result, the thermal difference from $5^{\circ}C$ to $10^{\circ}C$ meant the warning state. In addition, the thermal difference more than $10^{\circ}C$ meant that the connection status was unbalanced. In this case, the countermeasure might be the internal load distribution. If the thermal difference more than $20^{\circ}C$ is observed, it means a hot spot at the poor connection. If the hot spot is observed all over the surface, its cause was the unbalanced load, which made the conductive parts discolored and raised the possibility of oxidization or $Cu_2O$ generation. This diagnostic technology employing thermal image analysis method can be directly applied in the field and ensures the safety of equipments.

• 한국안전학회지
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• 제33권1호
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• pp.95-102
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• 2018

This study investigated the improvement of safety certification marking method and location marked on temporary equipments in order to guarantee the quality and safety of temporary equipments. The survey was performed for the stakeholder (manufacturers, lessors, and users) to find out the effective way that all stakeholder can agree each other. The main reason which users checked the safety certification making is that the mandatory safety certification marking can prevent the usage of poor and illegal temporary equipments. For the marking method, all stakeholder agreed that a depressed engraving method was an effective and usable displaying method. The opinions about the position of safety certification marking among the users, lessors, and manufacturers did not come into the agreement. The manufacturers preferred the marking position in which the engraving process is easy, but users wanted the conspicuous place such as vertical member. However, it is necessary to continuously study ways to adopt the position preferred by the users.

• Journal of Construction Engineering and Project Management
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• 제3권4호
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• pp.1-4
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• 2013

Excavation is most commonly used activity in all construction projects. All contracting agencies prefer to use bigger and heavier excavators and dumpers on site to do excavations if quantity of excavation is huge. Estimation of required number of excavators and dumpers for completion of excavation could be rather a tedious process involving repetitive calculation on which professionals spend their valuable time. As the Information Technology is highly involved in construction section there os need to have IT model for estimation of number of excavators and dumpers. The developed model is useful to calculate required equipments within short period of time. The purpose of the developed IT model is to save the time and efforts of the construction professional. The paper discusses about model which can be used on site to estimate numbers of excavators and dumpers required for completion of certain quantity of excavation within the given time. The calculation considers various existing formulas and method to generate the output. This information could certainly be useful in planning equipments on construction project sites. The tool is user friendly where any non IT background person can use it on construction sites.

• 한국과학교육학회지
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• 제16권1호
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• pp.35-40
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• 1996

Teaching materials are an important aspect to decide the quality of education. Science teaching materials include textbook, workbook, worksheet, OHP materials, posters, computer softwares, experimental equipments, slides, video tapes, and other audio-vidual materials. This comparing research is based on the contemporary teaching materials used in elementary schools of the United States and Korea in 1990s. The results of this study are : 1. The United States has more elementary science teaching materials such as posters, worksheets, computer softwares, OHP materials than Korea. Both countries developed elementary science textbooks, activity books, video tapes, science reading materials, and experimental equipments. 2. The frequancy of using these science teaching materials in Korea is bigger than that in the United States. In Korean elementary science classes, most of instructions are progressed by experimental activities. Korean elementary science textbooks are mostly consisted of science activities, but those of the United States includes science information, science related jobs, STS articles and some portion of science activities. 3. Experimental equipments of the United States are stronger than those of Korea. Various and excellent elementary science teaching materials such as computer softwares, posters, audio-vidual materials, and experimental equipments should be developed and used in elementary science classes for better elementary science education.

• 설비공학논문집
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• 제20권8호
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• pp.556-562
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• 2008

The building HVAC systems have very different qualities of performance and durability with the superintendent's ability for management and maintenance. The poor management of these systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. This study presents an example of appropriate use of the LCC(Life Cycle Cost) analysis in a process of maintaining and repairing old HVAC equipments, by demonstrating the difference of optimal economic life, decrease of running cost, and energy consumption according to the management level of the HVAC equipments. But there are no reliable life expectancy and performance history data at present for optimal management of various building service equipments. Therefore, it is necessary to construct long-term database on operation results of them for more accurate and optimized LCC analysis.