• 한국자동차공학회논문집
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• 제15권3호
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• pp.63-71
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• 2007

During the design phase of a product, reliability and design engineers are called upon to evaluate the reliability of the system, The question of how to meet target reliability for the system arises when estimated reliability or cost is inadequate. This then becomes a problem of reliability allocation and system structure design. This study proposes the optimization methodology to achieve target reliability with minimum cost through construction of the cost function of system. In cost function, total cost means the sum of initial cost, repair cost and maintenance cost. This study constructs optimization problem about system structure design and reliability allocation using cost function. This problem constructed is solved by Multi-island Genetic Algorithm(MIGA), and applies to urban transit brake system. Current brake system of the urban transit is series system. Series system is the simplest and perhaps one of the most common system, but it demands high reliability and maintenance cost because all components must be operating to ensure system operation. Thus this study makes a comparative study by applying k-out-of-n system to brake system. This methodology presented can be a great tool for aiding reliability and design engineers in their decision-makings.

• 대한교통학회지
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• 제28권2호
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• pp.111-121
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• 2010

도로계획 과정에서 차로수 설계에 필요한 장래 설계시간교통량은 설계시간계수 K를 사용하여 결정하고 있다. 30번째 순위교통량(V30)과 년평균일교통량(AADT)의 상대적 비율인 K30은 일년 8,760개의 시간교통량 중에서 30번째 시간교통량을 기준으로 도로계획의 수준을 결정하는 것을 의미한다. 대도시 주변의 고속도로를 대상으로 혼잡한 명절기간(설날, 추석 등)과 주말을 대상으로 시간교통량 순위를 살펴보면서 실제적으로 교통혼잡을 보인 명절기간 시간교통량이 의외로 낮은 순위에 위치에 있음을 밝혀내어 기존의 설계시간 교통량 추정방법에 문제가 있음을 밝혀내었다. 이를 개선하기 위하여 본 연구에서는 정체시간교통량을 통행수요로 전환하여 교통수요 개념을 가지고 설계시간계수(K)를 추정하는 방법을 새롭게 제시하고, 기존 방법에 의한 설계시간계수 K값과 비교, 평가하였다.

• 대한원격탐사학회지
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• 제30권3호
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• pp.399-415
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• 2014

The intensity of stormwater runoff is particularly acute across cities located in arid climates. During flash floods loose sediment and pollutants are typically transported across sun-hardened surfaces contributing to widespread degradation of water quality. Rapid, dense urbanization exacerbates the problem by creating continuous areas of impervious surfaces, perforated only by a few green patches. Our work demonstrates how the latest techniques in remote sensing can be used to routinely measure urban land cover types, impervious cover, and vegetated areas. In addition, multiple regression models can then infer relationships between urban land use and land cover types with stormwater quality data, initially sampled at discrete monitoring sites, and then extrapolated annually across an arid city; in our case, the city of Phoenix in Arizona, USA. Results reveal that from 30 storm event samples, solids and heavy metal pollutants were found to be highly related with general impervious surfaces; in particular, with industrial and commercial land use types. Repercussions stemming from this work include support for public policies that advocate environmental sustainability and the more recent focus on urban livability. Also, advocacy for new urban construction and re-development that both steer away from vast unbroken impervious surfaces, in place of more fragmented landscapes that harmonize built and green spaces.

• Journal of Nutrition and Health
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• 제15권4호
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• pp.290-300
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• 1982

The study deals with the empirical research on the condition of nutrient intake of low income class which be represented by urban slum and rural area, with the analysis of the factors which might influence on the prevalent condition of nutrient- intake. The method of the research was based on the spot-survey with questionaires. The result is that the levels of nutrient-intake are below the standard requirement level of nutrients in both of urban slum and rural area. The level of nutrient intake in urban slum lies in approximately 50% of the standard requirement level and 80% of the standard requirement level in rural area. The extent of malnutrition was explained in terms of the amount of calorie, protein, calcium and iron. More than half of the population in the community are below the standard requirement level of the nutrient- intake. The problem of malnutrition was serious in urban slum than in rural areas, which made a good contrast with the result of Peru study. Deficiency in calcium was most serious. The factor analysis of the prevalent condition of malnutrition in low class suggests that 1) The function of local market in supplying food is not so effective in the sense that the quality of the foods purchased id the local market is poor. 2) Low level of knowledge, the consequent ignorance and the indifference to the nutrition and the low income led to malnutrition. The level of income and the education were significantly correlated to the nutrient-intake.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.120-125
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• 2008

Many countries are faced with problems of energy demand and environmentally. Renewable energy is the interesting solution to deal this problems. In Korea, it is planed to apply the renewable energy to 5% of total energy demand by 2011. For this, the government has supported by various promotion program of renewable energy Policy Consideration of renewable energy system is essential for sustainable urban regeneration. Renewable energy application will be possible to make friendly environmental and sustainable city and deal with the energy and environment problem. This study will provide fundamental data to applying renewable energy systems for urban generation. There are evaluated for economic feasibility of renewable energy systems and analyzed application of them by building type as a urban energy source.

• 상하수도학회지
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• 제26권5호
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• pp.637-647
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• 2012

Recent series of flooding events in urban area has brought a growing concern on storage facilities as a major stormwater management method. The Korean Ministry of Environment has announced diverse plans to tackle the problem, including plans for multi-purpose storages which deal both the stormwater and wastewater. Even though storages can be categorized for different perspectives, classification of possible storages in urban area has not been throughly studied so far. This study investigated diverse references of urban storages and suggested systematic classifications on structural, functional and some other basis. Structural classification mainly concerns structural shape of facilities and includes (1)Cisterns & Rain barrels, (2)Forebays, (3)Dry basins, (4)Wet basins and (5)Constructed wetland. Those functions can be (1)flood prevention (2)water quality control and (3)reuse of stored water. Other criteria that categorize storages depend on (1)height, (2)location, (3)configuration, (4)depth, (5)site of the installation and (6)shape.

• Journal of Positioning, Navigation, and Timing
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• 제8권1호
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• pp.31-40
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• 2019

In recent years, Intelligent Transport Systems (ITS) and Autonomous Vehicle Technology have actively studied around the world. In order to achieve the purpose of Advanced Driver Assistance System (ADAS) and Autonomous Vehicle Technology, it must be obtained accurate and reliable positioning. However, the problem of positioning in the urban area is a low position accuracy caused by the reduction of the number of visible satellites due to high buildings. In this paper, we analyzed the availability of precise positioning system in urban area are using GPS/BDS integrated system. For this study, GPS and BDS satellite signals were collected using two low-cost receivers in the open sky and a designed software based platform for precise positioning performance analysis. And we analyzed the precise positioning performance by changing the mask angle considering the urban area. From the results, it can be confirmed that the performance of precise positioning of GPS only and BDS only decrease in the environment where mask angle is $40^{\circ}$ to $45^{\circ}$, however, GPS/BDS integrated system maintains high performance of precise positioning.

• 대한건축학회논문집:계획계
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• 제35권1호
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• pp.117-125
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• 2019

The purpose of this study is to examine urban built environments associated with the walking behavior in order to identify the problem of urban infrastructure from the perspective of Universal design theory. Using the walkability criteria developed based on the findings of previous studies on Universal design theory and walking environment, the urban built environments in old town area of Seoul were evaluated. The results of the evaluation indicated that the pedestrian infrastructure in the study area had several shortcomings to improve in order to provide walking-friendly environments. First, the pedestrian infrastructure for visually impaired people were severely limited. Second, walking traffics in large portion of the street networks were interrupted by a variety of obstacles such as parked cars, signboards, and illegal street shops. Third, there were certain areas where the quality of pavement was not properly managed. In summary, this study provides an empirical data to understand the current situation of pedestrian infrastructure in the urban areas. Improvement of pedestrian infrastructure is needed to address the issues related to the mobility of the disabled people. It is also recommended to construct the GIS data on walking environment in order to develop and mange a long-term public investment plan for walking-friendly urban environments.

• Journal of Contemporary Eastern Asia
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• 제19권2호
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• pp.148-168
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• 2020

In April, 2020, amid widespread fear of a second wave of infections of the novel coronavirus in China, local authorities in Guangzhou cracked down on the city's black population, resulting in mass evictions of Africans. The incident raises several questions about racism in China. How should we interpret this heavy-handed treatment of black people? Was this an isolated incident? What motivated such operations? In this article, I explain social control of Guangzhou's African communities as a problem of municipal politics. What underlies the government's heavy handed approach, I argue, are those communities' ties to rurality, which constitute a roadblock in the city's urban upgrade. Using Dengfeng Village, one of the best known African communities in China, as a case study, I show that efforts to upgrade the area by the local state and the real estate industry were frustrated by the community's status as an urban village. Africans, whom Chinese have historically associated with rurality, are seen as contributing to a space that has long been stigmatized as a spatial manifestation of rural people's lack of self-discipline. To better reveal the interconnection between social control and urban politics, I place official action in context of the history of the community's formation and the lived experience. This analysis of Dengfeng applies to various extents to other major African communities in Guangzhou.

• 건축역사연구
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• 제30권4호
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• pp.91-102
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• 2021

This study is a case study of system improvement measures for urban regeneration of the historical and cultural environment. The example areas are Hwangnam and Inwang Hanok districts in Gyeongju City, which operate various systems to solve the urban decline problem caused by the historical and cultural environment regulations. The subjects of this study are resident support programs and district unit planning systems under the advanced promotion system established in the case area. As research methods, literature studies, field surveys, and in-depth interviews were conducted. Through this, the background and purpose of introduction of each system, major plan contents, and problems of the system application process were analyzed. This study drew the following implications through case studies. First, in order to more effectively promote the urban regeneration of the historical and cultural environment, it is necessary to improve the related systems in an integrated and systematic manner. Second, in order to resolve the policy distrust of local residents in the historical, cultural and environmental management system, a wider variety of planned alternatives to narrow the difference in interests between the public and private sectors should be presented.