• Communications for Statistical Applications and Methods
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• 제28권3호
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• pp.281-294
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• 2021

In this paper, we propose an adaptive regression method based on the single-layer neural network structure. We adopt a symmetric activation function as units of the structure. The activation function has a flexibility of its form with a parametrization and has a localizing property that is useful to improve the quality of estimation. In order to provide a spatially adaptive estimator, we regularize coefficients of the activation functions via ℓ₁-penalization, through which the activation functions to be regarded as unnecessary are removed. In implementation, an efficient coordinate descent algorithm is applied for the proposed estimator. To obtain the stable results of estimation, we present an initialization scheme suited for our structure. Model selection procedure based on the Akaike information criterion is described. The simulation results show that the proposed estimator performs favorably in relation to existing methods and recovers the local structure of the underlying function based on the sample.

• 한국공간구조학회논문집
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• 제23권1호
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• pp.69-76
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• 2023

A timber lattice roof, which has around 30m span, was constructed. In order to figure out the realistic buckling load level, the structural analysis of this roof structure was performed especially by stiffness of connection with various asymmetric snow load. Due to the characteristics of application of snow load, the load combinations of snow should be considered not only global area but also local part so that the critical buckling load could be observed as easy as possible. Geometrical imperfection was simulated to consider inaccurate shape of structure. And then nonlinear analysis were performed. Finally, this paper could investigate that the asymmetric snow load with the lower level stiffness of connection decreased the level of buckling load significantly.

• 센서학회지
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• 제31권3호
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• pp.145-150
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• 2022

The importance of flexible polymer-based pressure sensors is growing in fields like healthcare monitoring, tactile recognition, gesture recognition, human-machine interface, and robot skin. In particular, health monitoring and tactile devices require high sensor sensitivity. Researchers have worked on sensor material and structure to achieve high sensitivity. A simple and effective method has been to employ three-dimensional pressure sensors. Three-dimensional (3D) structures dramatically increase sensor sensitivity by achieving larger local deformations for the same pressure. In this paper, the performance, manufacturing method, material, and structure of high-sensitivity flexible pressure sensors based on 3D structures, are reviewed.

• 한국지진공학회논문집
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• 제10권6호
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• pp.57-65
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• 2006

본 논문에서는 구조물의 전역적인 손상도 평가와 국부 구조 연결부의 손상 검색을 동시에 수행할 수 있는 하이브리드 구조 손상 모니터링 체계가 제시되었다. 하이브리드 손상 모니터링 체계는 진동기반 기법과 전기/역학적 임피던스 기법으로 구성되었다. 진동기반 기법은 구조물의 모드특징의 변화를 사용하여 구조물의 전역적 특성의 변화를 감지하고, 전기/역학적 임피던스 기법은 PZT 센서의 저항 변화를 사용하여 국부 구조 연결부의 손상 여부를 검출한다. 제안된 하이브리드 모니터링 체계를 검증하기 위해 구조 연결부의 볼트 풀림 상황을 손상 시나리오로 선택하였으며, 가속도 응답과 임피던스 응답 신호가 계측되었다. 실험 결과, 제안된 하이브리드 모니터링 체계를 통해 구조물의 전역적 손상 상태와 국부 구조 연결부의 손상을 정확하게 모니터링 할 수 있었다.

• 한국지역지리학회지
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• 제13권1호
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• pp.54-67
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• 2007

본 연구에서는 중국 대련시(大連市)에 투자한 한국기업의 지역적 뿌리내림을 경영관행에 초점을 두고 분석하였다. 이를 위해서 투자지역의 사회경제주제와 네트워크 관계의 측면에서 기업조직, 의사결정체계, 고용 및 노동관행 그리고 정부 및 협회를 비롯한 지원기관과의 관계 등으로 구분하여 파악하고자 하였다. 중국 대련시 한국기업의 주된 투자동기는 시장 확보이며, 이에 따라 주요 예산집행에 관한 의사결정은 한국 본사에 의하여 이루어지고 있으나 시장개척, 인력채용 등에 대한 의사결정은 현지법인의 자율성이 높은 경향이 있다. 투자지원정책 면에서 지방정부와의 협력이 잘 이루어지고 있고 기업은 경영성과를 지역사회로의 환원을 통하여 현지사회와의 융화를 위하여 노력하고 있으며 노사관계도 비교적 원활한 것으로 나타나고 있다.

• Computers and Concrete
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• 제33권2호
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• pp.195-204
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• 2024

Floor inertial forces are transferred to lateral force resisting systems through a diaphragm action during earthquakes. The diaphragm action requires floor slabs to carry in-plane forces. In precast concrete diaphragms, these forces must be carried across the joints between precast floor units as they represent planes of weakness. Therefore, diaphragm reinforcement with sufficient strength and deformability is necessary to ensure the diaphragm action for the floor inertial force transfer. In a shake table test for a three-story precast concrete structure, an unexpected local failure in the diaphragm flexural reinforcement occurred. This failure caused loss of the diaphragm action but did not trigger collapse of the structure due to a possible alternative path for the floor inertial force transfer. This paper investigates this failure event and its impact on structural seismic responses based on the shake table test and simulation results. The simulations were conducted on a structural model with discrete diaphragm elements. The structural model was also validated from the test results. The investigation indicates that additional floor inertial force will be transferred into the gravity columns after loss of the diaphragm action which can further result in the increase of seismic demands in the gravity column and diaphragms in adjacent floors.

• 한국농촌건축학회논문집
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• 제24권4호
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• pp.67-75
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• 2022

The purpose of this paper is to provide basic data to Si and Gun preparing for rural agreements in the future through consideration and case analysis for rural conventions, such things as living standards, hierarchical analysis methods, and general rural development projects. In the 1970s, sporadic and one-off projects focused on individual projects were repeatedly carried out in rural areas, which were undergoing dramatic changes in population movement, land use, landscape, economic growth and living. The keyword of the government's policy has changed to a way that existing rural development projects are planned and promoted by local governments themselves in conjunction with the issue of autonomy and decentralization. In addition, with the introduction of Rural Convention, the central and local governments are striving to achieve common policy goals. However, due to the lack of understanding of the Rural Convention introduced as a pilot project in 2020, the lack of living areas setting-standards, unclear classification of hierarchical structure, and excessive goal consciousness for general agricultural and fishing village development projects remain, fading the original purpose of the Rural Convention. Therefore, this study analyzed the seven reports of the Gyeongsang region selected in the 2021 Rural Convention to identify the characteristics of living area, hierarchical structure analysis, and detailed projects (rural center revitalization project, basic living base development project) and provided them as basic data. As a result of the study, first, according to the results of the hierarchical structure analysis, the first class was derived from 6 out of 7 Si and Gun. This is judged to be the result of the current rural population, social, and economic problems. Second, according to the results of the division of living areas, it was confirmed that except for one local government in seven cities and counties, the remaining six local governments were divided into three single living areas and three two living areas. This is the result obtained through a comprehensive review by overlapping the results of various analyses such as hierarchical analysis and resident surveys and OD data, and shows a different form from the existing upper or related plans. It is judged that this is the result of including qualitative contents such as residents' opinions along with various analyses when determining the living area. Third, the proportion of the budget for rural center revitalization and basic living base development projects to the total project cost subject to the Rural Convention was 59.6%, which was relatively higher than that of other general agricultural and fishing village development projects. It is judged that it is preferred because the unit project cost is relatively high in Si and Gun, and that quantitative results can be visually shown after the project is terminated.

• 한국전산구조공학회논문집
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• 제20권1호
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• pp.83-92
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• 2007

대형의 유체-구조물 연계시스템(FSI) 해석을 위해 많은 수치기법들이 있지만, 유체의 슬로싱에 의해 발생되는 집중적이고 불규칙한 동수압의 영향 때문에, 신뢰할 수 있는 수치 결과와 수치안정성을 확보하기 위해 매우 조밀한 메쉬를 필요로 한다. 그 결과, 신뢰할 수 있는 장기적인 시간 응답을 구하기 위한 수치해석은 상당히 많은 CPU 시간을 요구한다. 본 논문의 목적은 국부 상세 모델을 이용하여 LNG운반선의 화물창 시스템의 유탄성적 거동을 해석하기 위한 전역-국부 해석기법을 제시하고자 한다. 본 논문에서 제시한 해석기법의 타당성을 증명하고 이 기법을 통해 LNG운반선 화물창 시스템의 국부응답을 효율적으로 예측한 결과를 제시하였다.

• Earthquakes and Structures
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• 제17권6호
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• pp.557-566
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• 2019

The evaluation of the seismic hazard for a given site is to estimate the seismic ground motion at the surface. This is the result of the combination of the action of the seismic source, which generates seismic waves, the propagation of these waves between the source and the site, and site local conditions. The aim of this work is to evaluate the sensitivity of dynamic response of extended structures to spatial variable ground motions (SVGM). All factors of spatial variability of ground motion are considered, especially local site effect. In this paper, a method is presented to simulate spatially varying earthquake ground motions. The scheme for generating spatially varying ground motions is established for spatial locations on the ground surface with varying site conditions. In this proposed method, two steps are necessary. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function. An empirical coherency loss model is used to define spatial variable seismic ground motions at the base rock. In the second step, power spectral density function of ground motion on surface is derived by considering site amplification effect based on the one dimensional seismic wave propagation theory. Several dynamics analysis of a curved viaduct to various cases of spatially varying seismic ground motions are performed. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effect, to spatial ground motions with considering coherency loss, phase delay and local site effects are also calculated. The results showed that the generated seismic signals are strongly conditioned by the local site effect. In the same sense, the dynamic response of the viaduct is very sensitive of the variation of local geological conditions of the site. The effect of neglecting local site effect in dynamic analysis gives rise to a significant underestimation of the seismic demand of the structure.

• 음성과학
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• 제12권4호
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• pp.129-139
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• 2005

This paper investigates any possible correlation between the information structure and the occurrence of clause internal pauses in the spontaneous discourse. One of the possible functions of pause is its capacity to signal the information structure of the discourse. However, this aspect was not much explored in Korean spontaneous speech. In the present study, information structure of spontaneous speech was defined for each word or word group on the basis of the information structure analysis model proposed by Van Donzel (1999) and Roulet (1991, 1997). Thus, at a local level (words or word groups) of discourse structure, a distinction was made between three types of information, new, given and inferable. The results showed that clause internal pauses tend to appear more frequently before new information than other types of information. However compared to the total number of words or word groups it was not noticed any specific ordering concerning different kind of information status and pausing. It was however found that clause internal pauses did not appear randomly. The majority of them occurred at the initial part of the clause or the sentence. This tendency was mostly related to the division of sentence (or clause) into topic and comment. Thus, the role of pauses as a marker of information structure seems to be less effective in spontaneous discourse.