• Title/Summary/Keyword: Bottom-Up

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A Study on the Ultimate Strength Behavior for Ship Perforated Stiffened Plate (선체 유공보강판의 최종강도 거동에 관한 연구)

  • Ko Jae-Yong;Lee Jun-Kyo;Park Joo-Shin;Bae Dong-Kyun
    • Proceedings of KOSOMES biannual meeting
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    • 2005.05a
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    • pp.141-146
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    • 2005
  • Ship have cutout inner bottom and girder and floor etc. Ship's structure is used much, and structure strength must be situated, but establish new concept when high stress interacts sometimes fatally the area. There is no big problem usually by aim of weight reduction, a person and change of freight, piping etc. Because cutout's existence grow up in this place, and, elastic buckling strength by load causes large effect in ultimate strength. Therefore, stiffened perforated plate considering buckling strength and ultimate strength is one of important design criteria which must examine when decide structural concept at initial design. Therefore, and, reasonable buckling strength about perforated stiffened plate need to ultimate strength limited design . Calculated ultimate strength varied several web height and cutout's dimension, and thickness in this investigated data. Used program(ANSYS) applied F.E.A code based on finite element method.

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Development of Patient-Immobilizing Device for Total Body Irradiation (TBI) (전신 방사선치료(Total Body Irradiation, TBI)를 위한 한국인에 맞는 환자 고정장치에 관한 연구)

  • 김명세
    • Progress in Medical Physics
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    • v.13 no.3
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    • pp.114-119
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    • 2002
  • A immobilizing device that is essential for correct lung and lens shielding with homogenous dose distribution in fractionated total body irradiation was developed and it's efficiency was evaluated. The main frame was made of stainless steel bar (5 cm in diameter) to withstand up to 230 cm in height and 100 kg in weight to prevent any injury even in unconsciousness condition. The saddle was designed to adjust the body weight and hight of standing patients. Chest and back supporter were made of 1 cm acryl which could fix the lung block and cassette holder. Leather and sponge pedding were used for head rest to keep patients comfortable. The device was strongly fixed by specially designed bolts on the bottom panel which was made of 1 cm stainless steel and 10 cm thick wooden board. Precise manipulation ($\pm$2 mm) was possible by upper two pulleys and side handles. Average four minutes twenty five seconds were needed for exact setting in fractionated TBI. No significant difference of lung block location on repeated verification films was confirmed and relatively homogeneous dose distribution was measured in rando phantom experiments and patient treatments ($\pm$5%). This immobilizing device was very efficient to keep correct position of patients, which is essential for better result and less complication in fractionated TBI.

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Reproduction of Shallow Tides and Tidal Asymmetry by Using Finely Resolved Grid on the West Coast of Korea (서해연안 상세해상을 통한 천해조석 및 조석비대칭 재현)

  • Suh, Seung-Won
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.4
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    • pp.313-325
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    • 2011
  • Finite element grid system using h-refinement on the Yellow Sea was constructed based on previous study (Suh, 1999b) from 14 K to 210 K and special attention was concentrated on refining the coastal zone. In grid generation, depth change between adjacent points and non-dimensional tidal wave length ratio were considered. As a result approximately a quarter of the total nodes are located nearby 5 m of shallow area. Accurate bathymetry data using 30's and ETOPO1 with open boundary conditions of 8 major tidal constituents extracted automatically from FES2004 have been applied. In tidal simulation a 3-dimensional nonlinear harmonic model was setup and tidal amplification due to changes in vertical turbulent and bottom friction were simulated. In this study not only 8 major tidal constituents but also nonlinear shallow tides $M_4,$, $MS_4$ and long period $M_f,$, $M_{sf}$ were reproduced. It is found that implication of spatial variation of friction coefficient plays a very important role in reproduction of astronomical and shallow tides which are computed by iterative computation of nonlinear terms. Also it should be considered differently with respect to tidal periods. To understand the distribution of tidal asymmetry, amplitude ratio of $M_4/M_2$ and phase differences $2g(M_2)-g(M_4)$ were calculated. Tidal distortion ratio marks up to 0.2 on the west coast showing shallow coastal characteristics and somewhat wide range of ebb-dominances in front of Mokpo area are reproduced.

Urban Community as a Contested Practice: A Gap between Ordinary Practices and Civic Advocacy Discourse (경합적 실천으로서 도시 공동체: 일상 실천과 시민사회 옹호 담론 간의 간극)

  • Lee, Jae-Youl
    • Journal of the Korean Geographical Society
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    • v.51 no.2
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    • pp.269-281
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    • 2016
  • This article problematizes and interrogates the idea of 'community' which is increasingly important in Korean urban policy-making. For the purpose, this article scrutinizes, and compares, how ordinary citizen participants and civil society activist organizations in a 'community garden' program of Seoul make sense of, utilize, and practice the policy concept. The neo-Faucauldian perspective of 'governmentality' is employed to understand the association between the community-focused policy program and neoliberalism, but Barnett's( 2005) call for 'bottom-up governmentality' is taken seriously in order to avoid any deterministic interpretation. On the basis of this eclectic perspective on governmentality, this article presents empirical findings that may suggest a contestation over community between ordinary citizens and civil society activists. More specifically, ordinary citizen participants prioritize place-based, on-the-ground community experiences that are built on common cultivation practices, whereas civil society activists tend to consider community garden as a teleological governmental technology generative of particular citizen subjects. Civic community garden advocacy as such aims to address social, economic, and spatial problems that neoliberalsim has produced, but it also appears to be in a close association with neoliberal urban policy. Thus, the community activism's meaningfulness lies in its active intervention to neoliberal urban policy, but a gap between ordinary practical achievements and civic activism can be a potential danger to urban community policy. On the basis of this discussion, this article asks more detailed investigations about the taken-for-granted positivity of urban community (re)vitalization programs, and also examinations on whether and how such projects generates emergent tensions between ordinary achievements and policy prescriptions.

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Temporal and Spatial Variation of SST Related to the Path of Typhoons around the Korean Waters in Summer (태풍 통과에 따른 한국 연근해 수온 변동)

  • 서영상;김동순;김복기;이동인;김영섭;김일곤
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.627-636
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    • 2002
  • While typhoons were passing by the coastal and offshore waters around the Korean peninsula, the variations of the sea surface temperature (SST) were studied. To study on the variation, the data related to the 22 typhoons among 346 typhoons which occurred in the western Pacific during 1990∼1999, daily measured field SSTs at coastal and offshore, and imageries from advanced very high resolution radiometer on NOAA satellite during 1990∼1999 were used. The average variations of the SSTs were -0.9℃ at coastal waters and -2℃ at offshore around the Korean peninsula while the typhoons were passing by. In very near coastal waters from the land, the SST was not changed because the bottom depth of the coastal waters was shallower than the depth of thermalcline, while the typhoon was passing. The temporal and spatial variation of SSTs at coastal waters in summer were depended on the various types of the typhoons'paths which were passing through the Korean peninsula. When a typhoon passed by the western parts including the Yellow Sea of the Korean peninsula upwelling cold water occurred along the eastern coastal waters of the peninsula. The reason was estimated with the typhoon that was as very strong wind which blew from south toward north direction along the eastern shore of the peninsula, led to the Ekman transport from near the eastern coastal area toward the offshore. While cold water was occurring in the eastern coast, a typhoon passed over the coastal area, the cold water disappeared. The reason was estimated that the cold water was mixed up with the surrounding warm water by the effect of the typhoon. While a cold water was occurring in the eastern coast, a typhoon passed by the offshore of the eastern coast, there were the increasing of the SST as well as the disappearing of the cold water. While a typhoon was passing by the offshore of the eastern coast, the cold water which resulted from the strong tidal current in the western coast of the peninsula was horizontally spread from the onshore to the offshore. We think that the typhoon played the role of the very strong wind which was blowing from north toward south. Therefore, the Ekman transport occurred from the onshore toward the offshore of the western coast in the Korean peninsula.

Study of an Applicability of an Urban Design Method Using Artificial Life Theory (인공생명이론을 이용한 도시설계방법의 적용 가능성에 대한 연구)

  • Lim, Myunggu;Kim, Kyoontai
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.4
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    • pp.93-101
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    • 2018
  • A city is like a living organism that is born, grows and become extinct within an ecosystem. In recent years, more and more cities have been planned by designers rather than spontaneously growing over time. This planning means that if a city is not appropriately designed at the beginning, it is very hard to fix or adjust it later. A poor urban design inconveniences many people, and forces them to adjust to it. For this reason, it is important to design a city as optimally as possible at the design phase. One of the reasons why a city is not designed optimally is complexity. Previous urban design methods have attempted to resolve the complexity by using a top-down problem-solving method based on the experience and knowledge of the urban planner. However, such an approach does not have the organic characteristics of a bottom-up problem-solving method of an artificial life, based on the creation principle of the ecosystem. Therefore, in this study the general principle of artificial life, which can provide a solution to the bigger problems that accumulate as a result of the solutions to small units of problems, is adopted. This enables us to draw various urban design alternatives, and it proves that the alternatives, despite being drawn through a limited modeling method, have almost no differences from those designed by an expert, and its possibilities of future development has also been verified.

A Critical Assesment on the Shin-hwal-ryuk Policy as a New Regional Development Policy in Korea (신활력사업계획 수립 및 추진과정에 대한 평가와 개선 방안)

  • Lee, Jong-Ho
    • Journal of the Economic Geographical Society of Korea
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    • v.10 no.2
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    • pp.211-222
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    • 2007
  • This paper aims to evaluate the new regional development policy which is entirely focused on the lagging rural regions in Korea. The new regional development, called the shin-hwal-ryuk policy is to reflect the radical change in the idea and philosophy of rural development. Although traditional rural development policies were top-down-based and physical infrastructure-centered, the new rural development policy idea is based on bottom-up and soft infrastructure which is related to the promotion of regional innovation capacities. However, it is revealed that the new rural policy involves a variety of problems in the process of establishing and making progress the policy plan in a local level. In the operating process of the policy plan, the central government has shown too quick-tempered for achieving visible outcomes, while many of local government suffer from the lacks of professional capabilities to carry out the plan. I see that as a result of the mixture of these problems the new policy is regarded as 'passively localized process' by the central government rather than 'actively localizing process' by the region for building regional innovation capacity.

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Experimental Study on Influence of Ground Collapse due to Ground Water Level Lowering (지하수위 저하가 지반함몰에 미치는 영향에 관한 실험적 연구)

  • Kim, Sukja;Jung, Kwansue
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.11
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    • pp.23-30
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    • 2018
  • According to recent ground collapse occurrence, ground subsidence is increasing every year in downtown area, which is a social problem. The purpose of this study is to investigate the relationship between ground water level lowering and ground collapse through laboratory model experiments. After mixing 1:1 granite weathered soil with sand, sandy soil was formed as a relative density of 30%, 50%, and 80%. And then the changes of soil discharge with change of groundwater level were compared. The physical property of material of which particle distribution were well graded with maximu dry unit weight of $1.94kg/cm^3$ and internal friction angle of 37degrees. Ground water levels were measured at 10 cm, 20 cm, and 30 cm from the bottom. As a result, the experiment shows that the higher the groundwater level works the higher the discharge velocity and the magnitude of underground cavity also increases with elapsed time. Finally, the cumulative quantity of soil discharge occurred up to 30 kg at the elapsed time, 35 minutes. It was also confirmed that the range of ground collapse increased due to soil discharge with ground water level lowering.

Periodic Characteristics and Implications of Programs and Policies for Brownfield Management in the U.S.A. (미국 브라운필드 관리 프로그램과 정책의 시기별 특성과 함의)

  • Kim, Eujin Julia;Miller, Patrick
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.1
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    • pp.96-107
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    • 2015
  • Brownfield sites are beginning to be considered as potentially useful areas for landscape design and planning, with post-industrial areas such as water treatment facilities and military training bases being converted into useful landscapes such as parks and recreation areas. These redevelopments bring broad benefits through revitalizing communities and increasing property values, thus, increasing the demand for comprehensive management and planning policies. This study examines changes in U.S. brownfield policies and programs and, identifies their periodic characteristics over the thirty years since the Superfund program was introduced in 1980. A descriptive and interpretive approach was utilized, focusing specifically on a time sequential analysis of the data gathered from the overview of the Environmental Protection Agency's web-based documents and related literature. The primary changes in and characteristics of programs and policies were analyzed and divided into three periods : environmental protection, remediation and reuse, and comprehensive planning. Four major features were identified: relaxation and readjustment of regulation, diversification of support programs, a mix of top-down and bottom-up approaches, and database system building. The study examines how common brownfield problems such as site identification difficulties and assessment and remediation cost have been dealt with in the regulatory context and has implications for future policies and programs for effective brownfield planning and management in Korea.

Interactive Navigational Structures

  • Czaplewski, Krzysztof;Wisniewski, Zbigniew
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.495-500
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    • 2006
  • Satellite systems for objects positioning appeared indispensable for performing basic tasks of maritime navigation. Navigation, understood as safe and effective conducting a vehicle from one point to another, within a specific physical-geographical environment. [Kopacz, $Urba{\acute{n}}ski$, 1998]. However, the systems have not solved the problem of accessibility to reliable and highly accurate information about a position of an object, especially if surveyed toward on-shore navigational signs or in sea depth. And it's of considerable significance for many navigational tasks, carried out within the frameworks of special works performance and submarine navigation. In addition, positioning precisely the objects other than vessels, while executing hydrographical works, is not always possible with a use of any satellite system. Difficulties with GPS application show up also while positioning such off-lying dangers as wrecks, underwater and aquatic rocks also other naturaland artificial obstacles. It is caused by impossibility of surveyors approaching directly any such object while its positioning. Moreover, determination of vessels positions mutually (mutual geometrical relations) by teams carrying out one common tasks at sea, demands applying the navigational techniques other than the satellite ones. Vessels'staying precisely on specified positions is of special importance in, among the others, the cases as follows: - surveying vessels while carrying out bathymetric works, wire dragging; - special tasks watercraft in course of carrying out scientific research, sea bottom exploration etc. The problems are essential for maritime economy and the Country defence readiness. Resolving them requires applying not only the satellite navigation methods, but also the terrestrial ones. The condition for implementation of the geo-navigation methods is at present the methods development both: in aspects of their techniques and technologies as well as survey data evaluation. Now, the classical geo-navigation comprises procedures, which meet out-of-date accuracy standards. To enable meeting the present-day requirements, the methods should refer to well-recognised and still developed methods of contemporary geodesy. Moreover, in a time of computerization and automation of calculating, it is feasible to create also such software, which could be applied in the integrated navigational systems, allowing carrying out navigation, provided with combinatory systems as well as with the new positioning methods. Whereas, as regards data evaluation, there should be applied the most advanced achievements in that subject; first of all the newest, although theoretically well-recognised estimation methods, including estimation [Hampel et al. 1986; $Wi{\acute{s}}niewski$ 2005; Yang 1997; Yang et al. 1999]. Such approach to the problem consisting in positioning a vehicle in motion and solid objects under observation enables an opportunity of creating dynamic and interactive navigational structures. The main subject of the theoretical suggested in this paper is the Interactive Navigational Structure. In this paper, the Structure will stand for the existing navigational signs systems, any observed solid objects and also vehicles, carrying out navigation (submarines inclusive), which, owing to mutual dependencies, (geometrical and physical) allow to determine coordinates of this new Structure's elements and to correct the already known coordinates of other elements.

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