• 대한공간정보학회지
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• 제23권2호
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• pp.69-77
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• 2015

우리나라 대피시설의 종류는 재난유형별 대피계획에 따라 구분된다. 자연재난 대피의 경우, 시 군 구별로 수립되는 '안전관리계획'에 대피소의 입지 및 대피에 관한 사항이 포함된다. 그러나 인구수용이 용이하고 구조상 안전한 건축물을 지정하도록 되어 있을 뿐 대피소의 입지나 규모 등에 대한 정량적 기준은 마련되어 있지 않다. 따라서 현실적인 대피계획 수립을 위해서는 자연재난 대피소의 분포 및 대피면적에 대한 현황 분석이 우선시 되어야 한다. 도로경사 등 지형요소와 연령별 신체능력의 차이는 도보 대피 시 신속한 대피경로 분석을 위한 주요 요인이다. 이에 본 연구에서는 지형요소와 연령별 보행속도 차이를 고려한 3차원 기반의 최적 대피경로 산정방법을 제시하고, 서울시를 대상으로 기준 대피시간(7.5, 15, 30분)별 대피소 커버권역의 지역적 차이 분석을 통해 자연재난 대피소의 입지 문제점과 정책적 시사점을 도출하고자 한다. 주요 분석결과를 요약하면 다음과 같다. 첫째, 서울시 인구 1인당 평균대피면적은 $0.45m^2$로 분석되었다. 이는 최소 대피면적을 $1m^2$로 가정했을 때 서울시 전체 인구의 45%만 수용 가능하다는 것을 의미한다. 둘째, 기준 대피시간 7.5분 이내에 대피 가능한 인구비율은 서울시 전체 인구의 33%에 불과하였다. 셋째, 5~9세 어린이나 65세 이상 노인의 대피가능 인구비율은 15~49세 기준 보행속도 그룹에 비해 현저히 낮아짐을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제10권3호
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• pp.166-166
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• 1982

This study has been made to make an observation regarding present status of the coal mine props which is desperately needed for coal production, despite of great shortage of the timber resources in this country, and investigate the effects of diffusion process on the decay resistances of the mine props as applied preservatives of Malenit and chromated zinc chloride. The results are as follows. 1. Present status of the coal mine props Total demand of coal mine props in the year of 1975 was approximately 456 thousand cubic meters. The main species used for mine props are conifer (mainly Pinus densiflora) and hardwood (mainly Quercus). Portions between them are half and half. With non fixed specification, wide varieties of timber in size and form are used. And volume of wood used per ton of coal production shows also wide range from 0.017 cubic meter to 0.03 cubic meter. 2. Decay resistance test a) The oven dry weight decreased between untreated specimen and treated specimen has not shown any significantly, although it has shown some differences in average values between them. It may be caused by the shorter length of the test. b) The strength of compression test between untreated specimen and treated specimen has also shown the same results as shown in case of weight decrease. Reasons assumed are the same. c) The amounts of the extractives in one percent of sodium hydroxide (NaOH) between untreated and treated specimen have shown the large value in case of untreated specimen than that of treated. 3. The economical benifit between untreated and treated wood when applied in field has seen better in long tenn base in case of treated wood, although the primary cost of treated wood add a little bit more cost than that of the untreated wood.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권1호
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• pp.45-56
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• 2010

Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP) composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented dining composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.365-370
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• 2000

A sliding mode fuzzy control (SMFC) algorithm is applied to design a controller for a benchmark problem on a wind- excited building. The structure is a 76-story concrete office tower with a height of 306 meters, hence the wind resistance characteristics are very important for the serviceability as well as the safety. A control system with an active tuned mass damper is assumed to be installed on the top floor. Since the structural acceleration is measured only at ,limited number of locations without measurement of the wind force, the structure of the conventional continuous sliding mode control may have the feed-back loop only. So, an adaptive least mean squares (LMS) filter is employed in the SMFC algorithm to generate a fictitious feed-forward loop. The adaptive LMS filter is designed based on the information of the stochastic characteristics of the wind velocity along the structure. A numerical study is carried out. and the performance of the present SMFC with the ,adaptive LMS filter is investigated in comparison with those of' other control, of algorithms such as linear quadratic Gaussian control, frequency domain optimal control, quadratic stability control, continuous sliding mode control, and H/sub ∞///sub μ/, control, which were reported by other researchers. The effectiveness of the adaptive LMS filter is also examined. The results indicate that the present algorithm is very efficient .

• Steel and Composite Structures
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• 제51권6호
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• pp.647-659
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• 2024

Given the increased interest in enhancing structural sustainability, the current study sought to apply multiobjective optimization to a footbridge with a steel-concrete composite I-girder structure. It was considered as objectives minimizing the cost for building the structure, the environmental impact assessed by CO2 emissions, and the vertical accelerations created by human-induced vibrations, with the goal of ensuring pedestrian comfort. Spans ranging from 15 to 25 meters were investigated. The resistance of the slab's concrete, the thickness of the slab, the dimensions of the welded steel I-profile, and the composite beam interaction degree were all evaluated as design variables. The optimization problem was handled using the Multiobjective Harmony Search (MOHS) metaheuristic algorithm. The optimization results were used to generate a Pareto front for each span, allowing us to assess the correlations between different objectives. By evaluating the values of design variables in relation to different levels of pedestrian comfort, it was identified optimal values that can be employed as a starting point in predimensioning of the type of structure analyzed. Based on the findings analysis, it is possible to highlight the relationship between the structure's cost and CO2 emission objectives, indicating that cost-effective solutions are also environmentally efficient. Pedestrian comfort improvement is especially feasible in smaller spans and from a medium to a maximum level of comfort, but it becomes expensive for larger spans or for increasing comfort from minimum to medium level.

• 한국토양비료학회지
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• 제39권3호
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• pp.123-135
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• 2006

고령지 경사지에서 모래성분이 많은 사양토 (석비레) 개간지의 토양특성에 대한 공간변이성과 분포도를 작성하여 공간적 변이를 살펴보고자 각각 $10m{\times}50m$의 면적을 가지는 5개의 포장에서 감자, 양파, 당근, 배추, 무를 재배하여 시험을 수행하였다. 각 포장의 조사지점수는 토양수분 33, 토양경도 11, 작물수량 33이었다. Semivariance 분석 결과, 대부분의 모형은 spherical 모형을 따르고 있었으며, 각 모형에 대해 공간적으로 연속성이 인정되는 거리를 나타내는 범위 (range)는 감자재배구에서 33-35 m로 고르게 큰 값을 보였고, 배추재배지는 5-6 m로 모형에 대한 연속성이 낮은 것으로 나타났다. 수분과 경도 및 수량에 대한 변이계수는 14-59%로 다양하였고, 감자수량의 변이계수가 59%로 가장 높았으며, 무재배지의 수분은 14%로 낮았다. 표준편차 5% 유의수준에서 10%의 오차를 가지는 경우를 기준으로 적정시료의 수를 조사한 결과, 필요한 시료수는 수분 8-40개, 경도 7-25개, 수량 424-4,6787개가 필요한 것으로 분석되었다. Variogram과 분포도를 통해 수분과 경도 및 작물수량의 공간적 분포 및 변이성을 쉽게 파악할 수 있으며, 이를 활용한다면 보다 효율적이고 정밀한 토양관리가 가능할 것으로 판단된다.

• 자동차안전학회지
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• 제7권3호
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• pp.14-18
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• 2015

Toughened glass is known to have about four times larger external impact resistance than that of original glass. This study is aimed to verify that ceramic-printed toughened glass does not meet of GTR(Global Technical Regulations) No. 6 and its strength is lower than that of original glass through tests. The tests were conducted on the test pieces of original glass, toughened glass, and ceramic-printed toughened glass from five glass manufacturers. In Test 1, a 227g steel ball was dropped from a height of 2 meters, and damage was checked according to the test method of GTR No. 6. In Test 2, a steel ball was freely dropped from different heights and limited damage height was determined. In the result of Test 1 according to the test method of GTR No. 6, while all five test pieces of toughened glasses were not damaged, all the ceramic-printed toughened glass from the five manufacturers were damaged. In the result of Test 2, none of the five test pieces of toughened glass were damaged by a 10m ball drop, meanwhile, the original glasses were damaged by an average of 3m ball drop. And the results of the tests show that the ceramic-printed toughened glass does not have the features of toughened glass due to its very low strength. Therefore, this study contributes to the safety of consumers by considering the GTR No. 6, and by revising the toughened glass test method.

• 전기학회논문지
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• 제65권8호
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• pp.1466-1477
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• 2016

This paper analyzes the electrical characteristic such as the impedance(Z), inductance(L), and cable resistance($R_p$) according to the change of cable length in order to move the electrical sorting device for distinguishing between AF non-insulated track circuits from the center of railway to outside railway. The simulation is performed to check the voltage difference between the voltage of sender and the voltage of receiver and determine the possibility of the voltage restoration availability in the frequency filter band through the capacitor compensation. It was applied to the results of the simulation to the sorting devices installed in the actual field. It is proved the availability by checking the measured voltage characteristic according to the capacitor compensating change of $10{\mu}F$ and $16{\mu}F$ before, and after the length of cable is increased with 6 meters. Through this, the prevention of breakdown and damage to facilities and the prevention the safety-related accidents of line workers from the train are expected according to moving the sorting devices of AR non-insulated track circuits to outside railway.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.470-473
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• 2005

Spent nuclear fuels are regarded as a high level radioactive waste and they will be disposed in a deep geological repository. To maintain the safety of the repository for hundreds of thousands of years, the spent fuels are encapsulated in a disposal canister and the canister containing spent fuels should have the structural integrity and the corrosion resistance below the several hundreds meters from the ground surface. In this study, the concept of the spent fuel encapsulation process and the process equipment fur deep geological disposal were established. To do this, the design requirements, such as the functions and the spent fuel accumulations, were reviewed. Also, the design principles and the bases were established. Based on the requirements and the bases, the encapsulation process and the equipment from spent fuel receiving process to transferring canister into the underground repository including hot cell processes was established. The established concept of the spent fuel encapsulation process and the process equipment will be improved continuously with the future studies. And this concept can be effectively used in implementing the reference repository system of our own case.

• 대한의용생체공학회:의공학회지
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• 제24권6호
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• pp.523-531
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• 2003

본 연구에서는 표면 전극을 사용하는 8채널 전기자극 시스템을 개발하였고. 이 시스템을 이용하여 하반신 마비한자의 근력강화를 위한 전기자극 엑서사이즈와 FES 보행을 하였다. 본 연구에서 개발한 전기자극 시스템은 컴퓨터 프로그램, 전기자극기, 그리고 컴퓨터 프로그램과 전기자극기를 연결하는 통신부분으로 구성되어 있다. 컴퓨터 프로그램에서는 마우스를 이용하여 임의의 자극 패턴을 손쉽게 구성하고 편집학 수 있으며 이렇게 구성/편집된 자극 패턴은 동원곡선(recruitment curve)을 통하여 자극 파라미터로 변환된다. 자극 파라미터는 직렬통신을 이용하여 전기자극기에 전달된다. 전기자극기는 주제어부에 1개, 각 채널에 1개씩 총 9개의 마이크로프로세서로 구성되어 있다. 주제어부의 마이크로프로세서가 컴퓨터 프로그램과 통신을 하고 각 채널의 마이크로프로세서를 제어한다. 본 연구에서 개발한 기능적 전기자극 시스템으로 하반신 마비환자에게 100주 동안 전기자극 엑서사이즈를 실시한 결과 근력, 다리둘레, 그리고 피로저항성의 증가를 볼 수 있었다. 전기자극 엑서사이즈로 무릎신근(knee extensor muscle)이 체중을 지지한 수 있을 정도로 증가한 후에 FES 보행을 시작하였고, 현재 2분 동안 50m 이상 보행할 수 있다.