• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.23-33
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• 2008

The moment redistribution in continuous reinforced concrete beams is very feasible phenomenon, by which the efficiency and the economy in designing reinforced concrete members can be enhanced. However, to understand the structural behavior by moment redistribution phenomenon, it is desirable to verify its mechanism experimentally considering tension stiffening effect, the relationship of moment redistribution and beam deflection, crack pattern, and effective stiffness. Six reinforced concrete continuous beam specimens were fabricated, and each specimen had a dimension of 250 mm $\times$ 350 mm and 7,000 mm long. The location of de-bonding was taken as the primary test parameter to investigate tension stiffening effect. The moment redistribution ratio of the specimens was different depending on the position of de-bonding, and in particular no moment redistribution was observed when de-bonding exist at both ends, the maximum negative moment region and the maximum positive moment region.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.41-50
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• 2012

Most of the developed countries and Korea have continued to invest much money in developing low-carbon vehicles such as electric car, methanol car and hydrogen car to replace the conventional fossil fuel vehicles. Government and local governments of each country, however, grope to construct roads for bicycle and public bicycle rental systems because bicycle is the only ultimate and feasible non-pollution transportation. Most of the current bicycle monitoring systems have achieved automation of rental process in bicycle stations, but they can not monitor bicycles in use. This paper develops GPS-CDMA modem combined terminals and implements a LBS-based bicycle monitoring system using them for public bicycle rental system. The monitoring system collects location information from GPS-CDMA modem combined terminals attached on bicycles and presents the moving tracks of bicycles on a GIS map for easy return and redistribution of bicycles. Also, the system helps to prevent from theft and vandalism of bicycles and to recommend the nearest bicycle station.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.661-671
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• 2012

The purpose of this study was to analyze the core policies of local government directors by performing centrality analysis on their core policies using network text analysis method. From the research results, it was verified to some extent that major policies of local government directors were changing during the path to arrive at 5th civil election. However, according to policy type by Peterson (development policy, allocation policy and redistribution policy) it was found that they still focused on development policies. However, it is encouraging that the government directors elected in the 5th election started to pay attention to 'Culture' which is one of allocation policies.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.5
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• pp.41-51
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• 2010

For safe seismic evaluation and design, it is necessary to predict the plastic deformation demands of members. In the present study, a quick and reasonable method for the evaluation of member plastic deformations of dual systems was developed on the basis of results of elastic analysis, without using nonlinear analysis. Plastic deformations of beams, columns, and walls are functions of member stiffness, story drift ratio, and moment redistribution determined from elastic analysis. For dual systems with rigid connections between walls and beams, an increase in the plastic deformations of beams due to the rocking effect was considered. The proposed method was applied to 8-story dual systems and the predicted plastic deformations were compared with the results of nonlinear analysis. The results showed that the proposed method accurately predicted the member plastic deformations with simple calculations, but that for the accurate evaluation of member plastic deformations, the inelastic story drift ratio must also be predicted with accuracy. The proposed method can be applied to both the performance-based seismic design of new structures and the seismic evaluation of existing structures.

• Iberoamérica
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• v.21 no.1
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• pp.57-105
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• 2019

This paper deals with the regional asymmetries of MERCOSUR and regional development cooperation for its solution. Through the formation of a common market, the countries of Southern Cone expected to grow evenly. However MERCOSUR had structural asymmetry from the beginning and exposed policy asymmetry over time. It is basically due to the overwhelming influences of Brazil on MERCOSUR. With regard to asymmetries, Paraguay calls for special and differential treatment. Uruguay wants equitable application of market liberalization. Argentine emphasizes production integration based on the development of value chains. In the issue of asymmetries, while Paraguay, Uruguay and Argentine act as petitioners, Brazil is capable of selecting the initiatives. Under these circumstances MERCOSUR has established FOCEM as regional redistribution mechanism. FOCEM has achieved some results as seen in Paraguay, but there are still problems such as financial limitations and lack of enforcement. In oder to activate the redistributive mechanism for regional integration and to coordinate the policies to resolve regional disparities, transnational governance is essential but all member countries are reluctant to it. To date, regional asymmetries or development gaps have persisted and disparities in individual countries remains a problem.

• Electronics and Telecommunications Trends
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• v.30 no.2
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• pp.104-114
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• 2015

최근 무선통신서비스의 수요 급증에 따른 주파수 부족 심화 현상에 대해 제한된 주파수 자원의 재분배와 같은 해결책으로는 근본적인 극복이 어렵다는 공감대를 바탕으로 주파수 공유에 대한 연구가 다양한 분야에서 진행 중이다. 특히 인지무선기술은 무선통신에 관련된 모든 기술분야와 밀접하게 연관되어 다양한 기술분야의 협업을 통한 현 문제점을 해결할 수 있는 도전 기술임은 자명하다. 인지무선기술을 적용한 다양한 기술 표준들은 마무리 되었거나 마무리 단계에 있지만, 광의적 개념의 CR(Cognitive Radio)기술 측면에서 보면 아직도 해결해야 할 기술 이슈들이 산재해 있으며, 이러한 이유로 2014년 가트너 하이프 사이클상 태동기(innovation trigger)에 위치해 있다. 따라서, 본고에서는 최근 진행되고 있는 CR 관련 국내외 표준화 동향 및 기술개발에 대해 정리하고, 해결해야 할 주요 기술별 도전 이슈들에 대해 제시하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.875-878
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• 2008

Proxy MIPv6 환경에서 Local Mobility Anchor는 이동 단말에 대해 이동성을 제공하기 위한 등록과정과 데이터의 터널링을 제공한다. 다수의 Mobile Access Gateway에 위치하는 모든 이동 단말에 대해 서비스를 제공하여야 하기 때문에 Local Mobility Anchor는 병목현상을 일으킬 수 있으며 이것은 Local Mobility Anchor에 의해 관리되는 모든 이동 단말에 대해 전체적인 이동 서비스의 실패로 이어질 수 있다. 본 논문에서는 이러한 문제를 해결하기 위해 다수의 Local Mobility Anchor에 부하를 분배하며 특정한 Local Mobility Anchor에 부하가 집중될 경우 효과적으로 재분배하기 위한 기법을 소개한다. 본 논문에서 제안하는 기법을 통해 다수의 이동 단말에게 서비스를 제공하는 Proxy MIPv6 환경에서도 안정적이고 양질의 서비스를 제공하며 자원을 효율적으로 이용할 수 있을 것으로 기대된다.

• Explosives and Blasting
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• v.41 no.3
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• pp.38-61
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• 2023

An Excavation Damaged Zone(EDZ) caused by blasting impact changes rock properties, in situ stress distribution, etc., and its effects are noticeable at around a radioactive waste repository located at deep underground. In particular, the increase in permeability due to the formation of cracks may significantly increase the amount of groundwater inflow and the possibility of radioactive nuclide outflow. In this study, FLAC2D and FLAC3D were used to analyze the mechanical and thermal behaviors for three categories: a)No EDZ, b)Uniform EDZ, and c)Random EDZ. It was found that the tunnel displacement in the Random EDZ case was 423% higher than that in the No EDZ case and was 16% higher than that in the Uniform EDZ case. Tunnel inflow in the Random EDZ was also 17.3% and 10.8% higher than that in the No EDZ and the Uniform EDZ case, respectively. The permeability around the tunnel was increased by up to 10 times in the corner of the tunnel wall and roof due to the stress redistribution after excavation. From the computer simulation, it was found that the permeability around the tunnel wall was partially increased but the overall tunnel inflow was decreased with increase of stress ratio. Mechanical analysis using FLAC 3D showed similar results. Slight difference between 2D and 3D could be explained with the development of plastic zone during the advance of tunnel excavation in 3D.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.84-84
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• 2011

터널화재의 위험요소에 대한 해석을 위해서는 실제 상황을 재현한 실대형 실험이 가장 유용하겠지만 현실적으로 시간적, 공간적, 경제적인 제약이 따르기 때문에 CFD Modeling 기술의 이용 및 검증이 필요하고, 실제 상황에 가까운 현상의 재현을 위해서는 시뮬레이션의 정확도에 대한 향상이 필수적이다. 또한, CFD Modeling을 터널화재에 적용할 때 시뮬레이션의 질에 영향을 미칠 수 있는 요소들에 대한 결정이 선행되어야 한다. 우선, 터널의 기하학적 구조와 경계조건의 확립이 필요한데 필요한 정보를 얻기 위해서 어느정도 길이의 터널이 적절한지에 대해 생각할 필요가 있으며, 단면변화에 대한 결정을 통해 모델링을 수행하여야 한다. 모델링 작업이 선행된 후에 화재의 위치, 성장률, 최대 크기, 환기시스템 사항 등의 고려가 필요한데 이러한 조건들은 CFD Modeling의 결과에 직접적인 영향을 주기 때문에 충분한 사전조사가 이루어져야 하고, 각 사항들의 변수를 고려하여 다양한 화재시나리오의 도출이 가능할 수 있다. 마지막으로, 화재에서 발생된 열중 약 30%가 복사에 의해 주위 벽으로 전달될 수 있고 열은 연기가 가득찬 영역내에서 재분배될 수 있는데, 열전달 및 연기의 유동 등에 관한 자료를 기초로 화재현상에 대한 분석이 가능하다. 이러한 과정들을 통해 실제 상황에 가까운 설계화재 시나리오를 예측할 수 있다. 본 연구에서는 우리나라 최장대터널인 죽령터널에 대해 합리적인 가정을 통한 설계화재 시나리오를 기초로 화재시뮬레이션은 FDS(Fire Dynamics Simulator) 프로그램을 사용하여 화재 및 연기의 이동 양상을 분석하고, 피난시뮬레이션은 SIMULEX 프로그램을 사용하여 피난시간을 예측 함으로써 터널화재의 CFD Modeling에 의한 피난안전성을 검토하고자 한다.

• Tunnel and Underground Space
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• v.18 no.1
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• pp.1-9
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• 2008

Acoustic emission (AE) and Microseimsic (MS) activities are law-energy seismic events associated with a sudden inelastic deformation such as the sudden movement of existing fractures, the generation of new fractures or the propagation of fractures. These events rapidly increase before major failure and happen within a given rock volume and radiate detectable seismic waves. The main difference between AE and MS signals is that the seismic motion frequencies of AE signals are higher than those of MS signals. As the failure of geotechnical structures usually happens as a high velocity and small displacement, it is nat easy ta determine the precursor and initiation stress level of failure in displacement detection method. To overcame this problem, AE/MS techniques far detection of structure failure and damage have recently adapt in civil engineering. This study deal with the basic theory of AE/MS and state of arts in monitoring technique using AE/MS.