• 한국수학사학회지
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• 제26권2_3호
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• pp.177-195
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• 2013

본 연구는 대학수학능력시험 수리(수학) 영역의 개념 및 성격을 살펴보고, 수리(수학) 영역의 20년 변천 과정을 도입기(1994~1996학년도), 조정기(1997~2004학년도), 발전기(2005~2011학년도), 전환기(2012학년도 이후)로 구분하여 시기별 변천 과정을 고찰한 후, 향후 수학 영역의 과제를 제시하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.259-263
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• 2006

Development and maintenance of forests are very important at Korea which has mountainous topography of more than 60% of the national territory. Under the circumstances, variety period's data is being required for the continuous monitoring of forest area. In this study, change of forests type was analyzed using Landsat TM satellite image which have multi-spectral bands. Furthermore, change detection system for forests type was constructed on web for the periodical monitoring. By using this system, everyone can easily use for the monitoring of forest type's periodical change.

• 한국실내디자인학회논문집
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• 제25호
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• pp.191-197
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• 2000

This thesis is focused on the visitors varied experiences of the current museum architecture. The current trend and periodical development of visitors experiences are discussed by analyzing the factors such as the external symbol scheme, the exhibition space scheme, and the visitors circulation scheme which are involved with a visitors experience and thus classifying the experiences related to each sample museum. Examining and providing logical descriptions on each of the schemes helps comprehend the visitors varied experiences. This research, which deals with thoroughly understanding a museum as an architecture followed by taking visitors experiences into account, is aimed to contribute to improving visitors experiences in the course of designing a museum. The above-mentioned types of combination applied to each museum chosen for the research help understand the following : National museums show predominance of specific visitors experiences. As for the external symbol scheme, most of national museums have adopted the temple type, whereas international museums have equally adopted with the temple type and the showroom type which are characterized by its dedication to function and being in balance between contents and formalities.

• 한국농공학회지
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• 제32권4호
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• pp.61-70
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• 1990

In rural settlement planning, its spatial development framework should be constructed on the basis of the hierachial settlement system. However, up to now, there does not exist widely - accepted model on rural settlement hierachy. In this study the basic planning principles and directions on the modelling of the settlement hireachy in rural areas have been consolidated through theoretical study and situational analysis on planning environments. And also, a new yardstick on the grading of the middle - level centers between villages and rural towns has been tried to find out. The research resulted that the existance of periodical rural market might be used as a simple and innovative yardstick on the hierachial ordering of rural settlement system. Based on the above results, an alternative 4 - step model of rural settlement hierachy was proposed ; Rural Town(county hall sitted) -Market Center(having standard periodical market) - Village Center(having no market) - Village. Finally, because the conclusion has been made by very limited case studies and several previous works, there should need continuous studies and checks in future for full reasoning of the proposed model.

• 열처리공학회지
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• 제13권1호
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• pp.16-20
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• 2000

There have been little reports on the degradation of medium-carbon steel tubes served at high temperature for a long period. The purpose of this research was to provide the information of the proper replacement span of the tubes with the new ones. We investigated the medium-carbon steel tubes which were used at petrochemical plant for about 50,000 hrs to examine their mechanical properties and microstructures. Experimental results showed that the tubes satisfied the specification of ASTM despite such a long period of service, but mechanical properties, especially charpy impact values, were reduced. It concludes that the tubes on service at the plants needs a periodical inspection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.2214-2215
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• 2008

KESCO performed periodical inspection every 1${\sim}$3 years to check the status of maintenance and performance of electric installations for general use (less than 600V in voltage and 75kW in capacity in residential homes) but recently a resident have been avoiding periodical check due to increase of sex crime and empty house, which more and more difficult to secure electrical safety of installation. In order to solve non-inspection problems and improve efficiency of inspection, this paper introduce the model of remote monitoring system that check electrical facilites for general use and we are developing remote monitoring device for reliability test.

• 한국농촌건축학회논문집
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• 제10권4호
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• pp.17-24
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• 2008

The development of industry compared late with another area but the apartment industry in Junrabukdo has called into expansion in volume to the demand increase suddenly because the population concentrates on the cities by growth of economy rapidly. Under that conditions, the regionalism is to be strong that the degree of dependence on the first industry is to be high. But, it was care naught for the character of resident and offered a model apartment in continually that be in fashion in cities. Thereof demanders familiarized with that. There, the purpose of this work is to survey the character of apartment, aims of offer and basic material when plan of apartment in local city and rural.

• Steel and Composite Structures
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• 제45권6호
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• pp.831-837
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• 2022

Numerical investigation on dynamic characteristics of sandwich plates under periodic and thermal loads has been presented by assuming that the plate has three layers which are a foam core and two skins. The foam core made of Aluminum has porosities with uniform and graded dispersions. The sandwich plate has been supposed to be affected by periodical compressive loads. Also, temperature variation causes uniform thermal load. The formulation has been established based upon a higher-order plate theory and Ritz method has been used to solve the equations of motion. The stability boundaries have also been obtained performing Bolotin's method. It will be indicated that stability boundaries of the sandwich plate depend on periodical load parameters, porosities, skin thickness and temperature.

• 공업화학
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• 제16권5호
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• pp.653-659
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• 2005

동일한 마이크로파 조사 방식과 전계 강도에 의하여 마이크로파가 에멀젼에 조사될 경우 조사 시간이 길수록 많은 에너지가 에멀젼에 흡수된다. 그 결과로 에멀젼의 온도가 상승하고 점도는 낮아져 분리가 일어난다. 본 연구에서는 에멀젼 분리 효율의 향상을 위하여 마이크로파 조사 방식(연속식(continuous mode), 펄스식(pulsative mode), 주기식(periodical mode))에 의한 분리 효율의 비교 검토와 Sauter 평균 지름(Sauter mean diameter: $D_{32}$)을 이용한 에멀젼의 안정성에 관한 연구를 수행하였다. 각각의 조사 방식에 의하여 600 sec 동안 마이크로파가 조사된 30% W/O형 에멀젼(sample #1)을 24 h 침강시켰을 경우 연속식, 펄스식, 그리고 주기식에서 각각 60.0%, 62.3%, 그리고 96.2%의 오일 회수가 이루어졌고, 물 분리율은 26.5%, 35.0%, 그리고 93.9%를 나타내었다. Sauter 평균 지름($D_{32}$)은 연속식 $47.183{\mu}m$, 펄스식 $111.547{\mu}m$ 그리고 주기식에서 $220.476{\mu}m$로 주기식에서 가장 큰 값을 얻었다.

• 대한전자공학회논문지TC
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• 제44권11호
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• pp.67-77
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• 2007

센서 네트워크에서 센서 들의 통신키를 주기적으로 혹은 필요에 의해 갱신하는 것은 매우 중요한 문제이다. 동적인 키관리의 효율성을 기하기 위해, 센서 네트워크는 클러스터 구조를 도입하고 각 CH(Cluster Head)가 클러스터 내의 키를 관리하도록 한다. 그러나, 이러한 클러스터 기반 센서 네트워크에서 CH는 공격의 목표가 되기 쉽고, CH들의 오염은 네트워크 전체에 큰 위협을 가져온다. 본 논문에서, 우리는 CH들의 오염에 강건한 주기적인 키 갱신 방안을 제안하였다. 먼저, 제안방법은 CH가 관리하는 센서들의 수를 줄이고 CH들이 주기적으로 변경되게 함으로써, CH의 오염에 따른 영향을 최소화 한다. 둘째, 제안방법은 임의의 CH와 BS(Base Station)간의 키 설정에 다른 센서노드들을 참가시켜 공격자들을 혼란에 빠뜨린다. 우리는 수치적인 분석을 통해 제안방법이 다른 키 관리 방법들에 비해 안전하고 CH들의 오염에 강건함을 증명하였다.