• Smart Structures and Systems
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• 제23권6호
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• pp.669-682
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• 2019

Vibration mitigation of cables or hangers is one of the crucial problems for cable supported bridges. Previous research focused on the behaviors of cable with dampers or crossties, which could help engineering community apply these mitigation devices more efficiently. However, less studies are available for hybrid applied cross-ties and dampers, especially lack of both analytical and experimental verifications. This paper studied damping and frequency of two parallel identical cables with a connection cross-tie and an attached damper. The characteristic equation of system was derived based on transfer matrix method. The complex characteristic equation was numerically solved to find the solutions. Effects of non-dimensional spring stiffness and location on the maximum cable damping, the corresponding optimum damper constant and the corresponding frequency of lower vibration mode were further addressed. System with twin small-scale cables with a cross-link and a viscous damper were tested. The damping and frequency from the test were very close to the analytical ones. The two branches of solutions: in-phase modes and the out-of-phase modes, were identified; and the two branches of solutions were different for damping and frequency behaviors.

• Journal of East-Asian Urban History
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• 제2권1호
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• pp.65-85
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• 2020

Examining how the CCP operated social services in Shanghai neighborhood[linong] in early 1950s, this article reveals the hidden relation between social service and rectification of neighborhood organizations in 1954. One of the main purpose of 1954 rectification was to guarantee provision of grassroots level of the city by recruiting local cadres, the implementers of social services. Though series of social service, such as night patrol, cleaning and public charity were indispensable for residents' life and welfare(fuli)[福利] of neighborhood, the social services was the something most of the Shanghai residents were reluctant to do. The result was the shortage of human resource for social service, triggering the "nominal position(gua ming)[掛名] " phenomenon. During political rectification of neighborhood organizations in 1954 Shanghai Municipal government tried to solve this 'decline of human resource in social services' problem by attracting the unemployed to the position of basic level cadre. To be specific, it demanded jobless person in neighborhood to be registered in time if they want a job placement. And it used that registration as the nominee of cadre in re-election process of the rectification campaign. The government measures were closely related to Shanghai people's inclination to rely on party-state when they try to get a job. Hence political rectification in neighborhood organizations become the strategic tool of city governance to mobilize residents in operating social services. So this article suggests that the CCP's urban governance was a complex and nuanced process to induce urban residents' interest and voluntarism beyond the suppression-oriented totalitarian perspective.

• 대한건축학회논문집:구조계
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• 제35권6호
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• pp.129-137
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• 2019

The purpose of this study is to present systematic information and direction to urban underground space development industry, civil engineering and R&D. Regarding the development of urban underground space, the situation in Korea, especially now in Seoul, can be called an underground Renaissance. The Superground project, which has been going on for several years through international competition, is now completed and is about to open the Seoul Architecture Museum. Leading underground space complex development project of Yeongdongdaero, which is the largest living underground space in human history, spectral projects such as the Seoul section of the GTX routes, making underground roads of the Dongbu Expressway and the Seobu Expressway are now speeding up progress. Recently, plans have been made to use the underground more actively through the restructuring project of Gwanghwamun Square, the face of Seoul. And then, patents are indispensable resources for establishing a strategy for R&D as one of the indices showing what technologies have been developed and what technology development will be done in the future. Based on this background, this study attempts to classify and define the technical elements of urban underground space development through the analysis of patents of major countries in the world, and analyze and present state of technology level and situation accordingly.

• 자동차안전학회지
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• 제13권4호
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• pp.7-13
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• 2021

This paper presents an vulnerable road user (VRU) classification and tracking algorithm using vision and LiDAR sensor fusion method for urban autonomous driving. The classification and tracking for vulnerable road users such as pedestrian, bicycle, and motorcycle are essential for autonomous driving in complex urban environments. In this paper, a real-time object image detection algorithm called Yolo and object tracking algorithm from LiDAR point cloud are fused in the high level. The proposed algorithm consists of four parts. First, the object bounding boxes on the pixel coordinate, which is obtained from YOLO, are transformed into the local coordinate of subject vehicle using the homography matrix. Second, a LiDAR point cloud is clustered based on Euclidean distance and the clusters are associated using GNN. In addition, the states of clusters including position, heading angle, velocity and acceleration information are estimated using geometric model free approach (GMFA) in real-time. Finally, the each LiDAR track is matched with a vision track using angle information of transformed vision track and assigned a classification id. The proposed fusion algorithm is evaluated via real vehicle test in the urban environment.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.841-846
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• 2009

Recently, the construction industry is getting more complex and sophisticated having the characteristics of a mega project. Mega project pursues a value that can't be gained with an approach of seeing a project as just a simple sum of different parts but a mutual combination. However, the current manuals can't fulfill the needs for supporting, therefore, need a tool to support the decision making and an IETM is expected to take this role. Despite the a lot of expected advantages of IETM, it is still difficult to apply because of the frequent changes of information of detailed process and its complexity. In this research, as part of developing an IETM, we aim to propose a system frame which is based on the analysis of processes of a project. It is basic part of IETM to give information to users and IETM consists of normal mode that offers general information about the urban regeneration project and user-specified mode that gives classified and reorganized information to user. For supporting these functions, IETM should be stored in a form that can classify the information about urban regeneration project and be tagged with meaningful tags. Moreover IETM developers have to consider the interoperability of IETM because it ultimately should be coordinated with overall Project Management System like an iPMIS. We used XML for solution of interoperability because it stores information as just text-file that doesn't need a special form.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.122-122
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• 2020

Urban flood simulation plays a vital role in national flood early warning, prevention and mitigation. In recent studies on 2-dimensional flood modeling, the integrated run-off inundation model is gaining grounds due to its ability to perform in greater computational efficiency. The adaptive quadtree shallow water numerical technique used in this model implements the adaptive mesh refinement (AMR) in this simulation, a procedure in which the grid resolution is refined automatically following the flood flow. The method discounts the necessity to create a whole domain mesh over a complex catchment area, which is one of the most time-consuming steps in flood simulation. This research applies the dynamic grid refinement method in simulating the recent extreme flood events in Metro Manila, Philippines. The rainfall events utilized were during Typhoon Ketsana 2009, and Southwest monsoon surges in 2012 and 2013. In order to much more visualize the urban flooding that incorporates the flow within buildings and high-elevation areas, Digital Surface Model (DSM) resolution of 5m was used in representing the ground elevation. Results were calibrated through the flood point validation data and compared to the present flood hazard maps used for policy making by the national government agency. The accuracy and efficiency of the method provides a strong front in making it commendable to use for early warning and flood inundation analysis for future similar flood events.

• 대한토목학회논문집
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• 제26권1D호
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• pp.149-156
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• 2006

기존의 토지이용 분류방법은 현장조사에 의존하거나 항공사진 판독기법을 사용하므로 상대적으로 시간과 비용의 소요가 큰 편이다. 특히나 도시지역은 토지이용이 복잡하고 집약적이므로 위성영상을 활용해 분류하는데 한계가 있는 실정이다. 이러한 배경에서 본 연구에서는 1:1,000 수치지형도와 IKONOS 위성영상을 혼합 활용하는 토지이용 분류기법을 제기하였다. 본 연구에서 제기한 분류기법의 활용가능성을 파악하기 위하여 서울시 일부지역을 대상으로 실험분석을 수행하였으며, 그 결과 95%의 전체정확도와 14개의 토지이용 항목이 분류되었다. 실험분석의 결과로 미루어 본 연구에서 제기한 분류기법은 도시지역 토지이용분류에 적용 가능한 것으로 판단된다.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.367-374
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• 2013

Underground infrastructure systems provide essential public services and goods through buried structures including water and sewer, gas and petroleum, power and communication pipelines. The majority of existing underground infrastructure systems was installed in green field areas prior to development of complex urban built environments. Currently, there is a global trend to escalate major demand for underground infrastructure system renewal and new installation while minimizing disruption and maintaining functions of existing superstructures. Therefore, Engineers and utility owners are rigorously seeking technologies that minimize environmental, social, and economic impact during the renewal and installation process. Trenchless technologies have proven to be socially less disruptive, more environmentally friendly, energy conservative and economically viable alternative methods. All of those benefits are adequate to enhance overall sustainability. This paper describes effective sustainable solutions using trenchless technologies. Sustainability is assessed by a comparison between conventional open cut and trenchless technology methods. Sustainability analysis is based on a broad perspective combining the three main aspects of sustainability: economic; environmental; and social. Economic includes construction cost, benefit, and social cost analysis. Environmental includes emission estimation and environmental quality impact study. Social includes various social impacts on an urban area. This paper summarizes sustainable trenchless technology solutions and presents a sustainable construction method selection process in a proposed framework to be used in urban underground infrastructure capital improvement projects.

• 대한토목학회논문집
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• 제36권5호
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• pp.927-936
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• 2016

본 연구는 도시공원의 유형 및 입지적 특성이 공동주택 가격에 미치는 영향을 분석하기 위한 논문으로 부산광역시 전체를 연구대상지로 설정하였다. 공원은 환경재로서 주변으로의 영향력이 크게 작용함에도 불구하고 기존 논문들의 경우 공원 자체만을 대상으로 가치를 평가한 연구가 대부분이다. 이에 본 연구에서는 공원과 인근 공동주택과의 관계를 분석함으로서 그 경제적 가치를 판단하고자 한다. 특히 공원과 공동주택 그 자체의 물리적 객관적 특성을 반영하였다는 점에서 의의를 가진다. 또한 공원의 유형을 세부적으로 나누어 분석함으로서 유형별 특징을 분석함에 주안점을 두었다. 분석결과 공동주택의 층수, 해당 단지의 총 세대수, 건설사 도급순위, 공원지정 경과년수, 부도심 입지여부 등이 주택가격에 양(+)의 영향을 미치는 것으로 나타났다. 반대로 공동주택의 면적, 건축연한, 공원 조성계획 수립여부, 공원과 공동주택과의 거리, 도심입지여부, 지역생활권 입지여부 등은 음(-)의 관계로 분석되었다. 특히 공원별 유형에서 근린공원, 소공원, 체육공원은 공동주택 가격에 양(+)의 관계를 보였으나 어린이 공원의 경우 음(-)의 관계로 나타났다. 공원과 공동주택의 거리가 가까울수록 공동주택의 가격이 오르는 것은 공원이 주는 다양한 이점을 많은 사람들이 선호하게 되는 것을 의미한다. 이에 공원의 가치를 높이고 조성으로 인한 효과를 최대화하기 위하여 좀 더 다양한 방안으로의 노력이 필요할 것으로 사료된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.321-324
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• 2005

In these days, the management and visualization of 3D geo-spatial information is regarded as one of an important issue in GiS and remote sensing fields. 3D GIS is considered with the database issues such as handling and managing of 3D geometry/topology attributes, whereas 3D visualization is basically concerned with 3D computer graphics. This study focused on the design and implementation for the OpenGL API-based rendering system for the complex types of 3D geo-spatial features. In this approach 3D features can be separately processed with the functions of authoring and manipulation of terrain segments, building segments, road segments, and other geo-based things with texture mapping. Using this implementation, it is possible to the generation of an integrated scene with these complex types of 3D features. This integrated rendering system based on the feature-based 3D-GIS model can be extended and effectively applied to urban environment analysis, 3D virtual simulation and fly-by navigation in urban planning. Furthermore, we expect that 3D-GIS visualization application based on OpenGL API can be easily extended into a real-time mobile 3D-GIS system, soon after the release of OpenGLIES which stands for OpenGL for embedded system, though this topic is beyond the scope of this implementation.