• Geomechanics and Engineering
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• 제17권6호
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• pp.565-572
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• 2019

Spatial variability is an inherent characteristic of soil, and auto-correlation length (ACL) is a very important parameter in the reliability or probabilistic analyses of geotechnical engineering that consider the spatial variability of soils. Current methods for estimating the ACL need a large amount of laboratory or in-situ experiments, which is a great obstacle to the application of random field theory to geotechnical reliability analysis and design. To estimate the ACL reasonably and efficiently, we propose a micro-structure based numerical simulation method. The quartet structure generation set algorithm is used to generate stochastic numerical micro-structure of soils, and scanning electron microscope test of soil samples combined with digital image processing technique is adopted to obtain parameters needed in the QSGS algorithm. Then, 2-point correlation function is adopted to calculate the ACL based on the generated numerical micro-structure of soils. Results of a case study shows that the ACL can be estimated efficiently using the proposed method. Sensitivity analysis demonstrates that the ACL will become stable with the increase of mesh density and model size. A model size of $300{\times}300$ with a grid size of $1{\times}1$ is suitable for the calculation of the ACL of clayey soils.

• ETRI Journal
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• 제30권3호
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• pp.355-364
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• 2008

Multiple-input multiple-output (MIMO) systems can provide significant increments in capacity; however, the capacity of MIMO systems degrades severely when spatial correlation among multipath channels is present. This paper demonstrates that the influence of shadowing on the channel capacity is more substantial than that of multipath fading; therefore, the shadowing effect is actually the dominant impairment. To overcome the composite fading effects, we propose combining macroscopic selection diversity (MSD) schemes with MIMO technology. To analyze the system performance, the capacity outage expression of MIMO-based MSD (MSD-MIMO) systems using a characteristic function is applied. The analytic results show that there are significant improvements when MSD schemes are applied, even for the two-base-station diversity case. It is also observed that the effect of spatial correlation due to multipath fading is almost negligible when multiple base stations cooperatively participate in the mobile communication topology.

• 전자공학회논문지D
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• 제35D권5호
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• pp.24-32
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• 1998

Spatial green's functions for a horizontal magnetic dipole in a parallel-plate waveguide are expressed in an improved closed-form with two-level approximation of the spectral green's functions. The results evaluated by the present closed-from green's function with two-level approximation are compard with those obtained the previous closed-form green's function with one-level approximation. The present results are observed to be more acurate than the previous results over wide frequency range as well as whole spatial range. The combination of the present closed-form green's functions and the moment mehtod may help in analyzing the problem of EMP coupling through an aperture into a parallel-plat waveguide and the microstrip slot antenna with a reflector.

• 교육시설 논문지
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• 제24권1호
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• pp.3-10
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• 2017

This study is to analyze the remodeling method of library in terms of space extension method and urban regeneration by repurposing function in unused facilities through case study. In many case of library extension, horizontal extensions are more frequent than vertical extensions, because there are limits to extend vertically due to high live load estimation by book stacks. Extension schemes was organized by new building extension method in connection with existing buildings, attaching method small scaled mass or linear mass to existing building, connecting method a plurality of existing small buildings, vertical extension method on the top of the structure, underground extension method using special structure. Unused facility remodeling to the library, large scaled buildings can be developed completely to the function of the library through the relocation of the space, while small scaled building needs spatial extension. In the case of spatial extension, existing space that was used for other purposes can be used as a reading room or office, avoiding high live load estimation.

• Journal of Information Technology Applications and Management
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• 제30권1호
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• pp.11-19
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• 2023

To remove unnecessary background from tooth X-ray images and enhance the sharpness of tooth and gum images, image processing techniques including contrast adjustment and histogram equalization are used. The introduction of two methods for detecting the boundary of the tooth and gum region and separating the tooth and gum from the background. In both cases, the background of the tooth X-ray images could be removed as a result, improving the quality of the images. The proposed method improves MTF (Modulation Transfer Function), an image performance indicator, as a result of measuring MTF. The original image's spatial frequency ranged from 4.73 to 11.40 lp/mm at the 10% response, whereas the proposed image's spatial frequency ranged from 10.90 to 11.85 lp/mm, giving uniformly enhanced results. In contrast, tooth and gums could not be completely separated from the background using Apple's Lift subject from background function.

• 한국공간구조학회논문집
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• 제12권2호
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• pp.55-63
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• 2012

본 연구는 학교 건물의 구조적 성능 평가를 통한 내진보강에 대한 연구이다. 본 연구의 목적은 학교 건물의 구조적 성능평가를 통하여 안전성과 사용성을 고려한 구조보강방안을 비교분석하고 합리적 내진 보강안을 제시하여 보다 지진에 안전한 건축물을 유지하는데 도움 이 되고자 한다. 이 목적을 위해 기존의 학교건물을 연구 대상으로 선정하여 내진성능평가를 실시하고 내진 보강안을 제시하였다. 본 연구의 방법은 기존의 철근콘크리트 학교건물을 대상으로 1차 내진 성능평가와 2차 내진 성능평가를 실시하였다. 위와 같은 방법으로 내진성능평가를 하여 그 결과를 분석하고 내진보강방안을 제시(강재댐퍼, 탄소막대보강재)하였다. 제시된 내진 보강방안을 대상 건축물에 적용하여 내진보강 전, 후의 내진성능평가를 통해 종합적인 결과를 도출 하였다.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2503-2510
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• 2014

본 연구는 평상시에는 주민시설의 기능을 수행하며, 재난의 발생 시에 주민의 대피시설로 기능전환이 가능한 주민시설의 디자인 방법을 모색하는 것에 목표를 둔다. 이를 위하여, (1)재난 및 대피공간관련 용어의 정의, (2)관련 법령 및 기준의 현황, (3)기존의 건립된 주민시설(체육센터, 문화센터)의 수용기능 현황 및 특성 등을 연구하였으며, 기능전환형 주민시설의 디자인을 위한 (1)공간구성의 요구사항, (2)미래형 주민시설을 디자인하기 위한 방안 등에 대해서 문헌연구를 진행하였다. 시 군 구의 주민시설의 계획단계에서 설계지침의 작성 시, (1)대피관련 기능의 수직적 집적화, (2)프라이버시를 고려한 공간구획 및 건축적 장치, (3)화장실, 샤워시설 등의 배치와 출입구의 적절한 복수계획 및 배치, (4)단위공간의 적정규모 등이 기능전환형 주민시설의 디자인에서 중요한 요소로 파악되었다. 향후 기능전환형 주민시설 디자인의 가이드라인이 수립되어 이재민의 발생이라는 부득이한 상황이 발생했을 때 주민의 심리적 불안감을 최소화 하면서 대피공간의 기능을 수행한다면 바람직하다고 생각된다.

• 대한물리의학회지
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• 제5권3호
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• pp.385-394
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• 2010

Purpose : The present study was to examine the difference and severity of asymmetry in independently ambulating stroke survivors and to establish the association between gait asymmetry, velocity, and the motor function of lower extremity. Methods : The subjects used in this study were 43 subjects with hemiparesis being able to walk independently. Motor function of lower extremity was measured clinically with the Fugl Meyer-Lower /Extremity Assessment. Overground gait velocity and spatia-temporal parameters were collected by the GAITRite system. Results : Thirty(69.77%) patients showed statistically significant temporal asymmetry while 28(65.1%) exhibited statistically significant spatial asymmetry. One-way ANOVA results showed a main effect of temporal asymmetry group(normative, mild, severe) for gait velocity(F=74.129), FM-L/E(F=17.270), swing-stance symmetry(F=66.869, F=13.485, respectively), spatio-temporal asymmetry(F=13.166, F=31.800, respectively) 66, F=31.800, respectively). Gait velocity was negatively associated with temporal asymmetry(r=-.83), spatial asymmetry(r=-.60). Motor function of lower extremity was also associated with temporal asymmetry(r=-.58), and spatial asymmetry(r=-.50). Conclusion : The study attempted to establish the standard assessment of hemiparesis gait symmetry in light of the complex relationship with motor impairment and gait velocity. More future work will need to link the degree of gait asymmetry to clinically relevant outcomes to better establish the clinical significance of such observations.

• 한국지리정보학회지
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• 제12권2호
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• pp.120-131
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• 2009

본 연구는 다핵구조를 형성하고 있는 대도시의 도시공간구조 진단을 위해 도심 및 부도심의 인구분포상의 구심력 및 유효범위의 변동성을 측정하였다. 이를 위해 부산광역시를 대상으로 1995년부터 2005년까지 5년 간격으로 도심 및 부도심의 인구구심력의 유효범위 변화를 측정하고자 5km 단위로 범위를 확장하여 인구밀도함수 중 음지수함수를 활용한 결정계수 값의 변동성을 분석하였다. 이를 통해 인구분포에 대한 공간적 영향권역의 변동성을 파악하여 도심 및 부도심의 생성, 성장, 쇠퇴 등의 진행과정에 따른 각 과정별 도심 및 부도심의 인구구심력의 유효범위와 도심 및 부도심간의 충돌과정에서의 유효범위 변화과정을 분석하였다. 분석결과를 요약하면 중앙동은 지속적인 결정계수의 감소를 보이고 있으며 서면(부전동)은 설명력이 큰 변화없이 유지되고 있는 것으로 나타났다. 도심으로부터 5km씩 거리를 늘려 인구밀도함수를 적용한 경우에도 부전동의 경우는 10km이후부터 중앙동은 15km구간 이후부터 대체로 증가하였다. 전체적으로는 부산의 인구가 감소추세임에도 불구하고 지속적인 분산화 단계인 것으로 나타나 보다 효율적인 도시공간구조를 형성하기 위해 도심 및 부도심지역의 도심기능강화와 인접지역의 양호한 주거지역 공급이 필요한 것으로 판단된다. 본 연구의 결과는 도시공간구조의 변동성이 갖는 구체적인 공간적 차원의 정보를 제시하여 효율적 공간구조의 재편을 위한 정책적 접근의 기초자료로의 활용이 기대된다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제21권2호
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• pp.55-65
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• 2015

Purpose: Korea is increasing in the demand for medical services due to rapid economic growth and population aging in modern society. Thus, the importance has been emphasized for the health promotion in the community and the publicity and substantiality of public health centers. However, the environment is insufficient, compared to required functions and developed services as a urban public health center. The purpose of this study is to analysis the plane type and area composition of public health centers in Busan and to identify the property of their spatial configuration Methods: Eight public health centers in Busan, were classified, which had been selected as a medical tourism city. Subsequently, space requirements were analyzed, facilities were typed, vertical, horizontal spaces were reviewed, and area ratios by business function were calculated. Results: A review of the property of spatial configuration and an analysis of the area ratio revealed the three findings. 1)The horizontal analysis found various types: a single type, a multi-type, a radial type, and a circular type, 2)The vertical analysis showed that since a care function (general practice), and a task function (maternal and child health) were concentrated in lower level spaces, the lobby and core were closed located for providing quick medical services. 3)The analysis of the area ratio in public health centers in terms of their function indicated that each public health center' programs had the greatest influence on the area. Implications: This study attempted to present spatial structural problems and improvements for city public health center by identifying their state and classify their functions and types and by calculating the ratio of their area configuration according to the spatial composition. It was thus aimed to presenting implications in establish public functions and roles by activating business through in connection with the number of municipalities in many ways, such as regional health. medical welfare, etc. to improve the health of local residents, and by providing differentiated programs in accordance with local characteristics.