• 한국ITS학회 논문지
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• 제9권6호
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• pp.63-82
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• 2010

지속적인 도로 건설에도 불구하고 자동차의 급격한 증가와 주변 택지개발로 인해 고속도로 상습지정체가 나날이 심화되어 교통관리의 필요성과 운전자에 대한 교통정보제공 요구가 크게 부각되고 있다. 고속도로의 상습지정체를 해소하기 위해서는 혼잡의 원인과 유형, 특성에 따라 최적의 혼잡관리기법을 도출하고 사전 시행효과가 검토되어야하나, 기존의 교통분석 프로그램들은 국내 도로 및 교통조건, 교통류특성 등에 대한 반영 및 기 구축된 교통관리시스템(FTMS)과의 연계가 미흡하여, 효율적으로 고속도로 교통분석을 수행하기에는 시간적, 비용적으로 많은 제약이 따른다. 따라서 본 연구에서는 고속도로 교통관리시스템의 수집자료에 기반하여 체계적이고 과학적인 혼잡관리방법론을 적용하기 위해 한국형 교통분석 모형 및 프로그램(ExTRAM)을 개발하였다. VISSIM과의 비교결과, 정체에 대한 모사와 대안평가에서 ExTRAM의 결과가 다소 나은 것으로 평가되었다. ExTRAM에 대한 보다 엄밀한 검증을 위해 오산~수원 구간의 15분 집계간격의 평균통행시간(TCS데이터)을 이용한 한 달 동안의 장기간 테스트를 수행한 결과, 평균통행시간 오차가 2.48분이었고, 최대 및 최소 오차가 각각 15.02분 및 0.03분으로 나타나 ExTRAM의 교통분석 결과가 일정 수준의 정확도를 보이는 것을 확인할 수 있었다.

• 한국터널지하공간학회 논문집
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• 제17권4호
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• pp.487-497
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• 2015

도심지 교통량의 증가로 터널구간의 정체현상을 해결하기 위해 기존의 터널을 활용하여 증축 혹은 개축하는 단면 확대공사가 최적의 대안으로 고려되고 있다. 기존의 단면 확대기술은 교통흐름을 차단하고 시공하나, 최근 프로텍터를 활용하여 교통흐름을 유지할 수 있는 교통류 보존형 터널 단면 확대기술이 개발되었다. 이 기술은 교통흐름을 보존하여 수많은 사회적 손실을 최소화 할 수 있으나, 교통흐름을 보존하기 위한 프로텍터의 설치 및 운영으로 경제성 측면에서 불리할 수밖에 없다. 이러한 단면 확대기술들의 경제성을 적절히 평가하기 위해서는 시공중 교통흐름을 고려한 사회적 손실비용을 고려할 필요가 있다. 따라서 본 연구에서는 터널단면 확대 시공기술의 교통흐름을 고려한 사회적 손실비용을 산정하는 방법을 제시하는 것을 목표로 하였다. 그리고 매봉터널을 대상으로 사례연구를 수행하여 교통흐름에 따른 사회적 손실비용의 차이를 분석하는 것을 목표로 하였다.

• 한국지반신소재학회논문집
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• 제18권4호
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• pp.87-95
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• 2019

토공량 산출은 건설현장에서 최적 공사비 산정을 위한 데이터로 정확한 토공량은 토목 공사의 설계 단계에서 시공단계까지 고려되어야 하는 중요한 요소이다. 토공량 산출을 위해서는 정확한 지형 자료와 정밀한 토공 부피 계산이 필요하다. 본 논문에서는 짧은 시간에 정확한 지형 파악이 가능하고, 경제성 측면에서도 장점을 갖는 드론 측량 기술을 이용하여 고정밀 토공량 산출 시스템을 도출하였다. 시스템의 정확도 검증을 위해 현장 검증시험을 수행하였으며, 드론을 이용한 토공량 산출 결과와 GPS 측량 장비를 이용한 토공량을 비교·분석하였다. 또한, 새롭게 개발한 토공량 부피 계산 알고리즘을 기존 항공사진측량 소프트웨어(Pix4D) 계산 방식과 비교하여 정확도를 검증하였다.

• 전기학회논문지
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• 제67권5호
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• pp.680-687
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• 2018

Because of its predictability of the energy cycle and huge scale power output, the ocean energy from tidal power utilization has always received attention as a great energy source, even though its development cost, including the embankment construction, is so much higher than that of any other energy source. Nevertheless, nowadays many projects are being planned on account of institutional support from the government and the recent advance of construction technology. In Korea, the new industry field operating and managing the tidal power plant has already opened. But we are facing a number of problems for optimal operation of tidal power plant that are a lack of operation experience and a skill of professional management and others. This paper suggests a novel way to determine the starting head of power generation by generating power comparison method For this new method, the paper discusses many factors including changing the volume of the basin, the number of operating turbines and gates and forecasting the tidal amplitude and the characteristic curve of turbine and gate. Finally we verified that it can increase about 2% an annual power generation compared with the conventional method using the original operational function made in the plant design process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1911-1930
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• 2017

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. The key to overlay routing is the placement and maintenance of the overlay infrastructure, especially, the selection and placement of key relay nodes. Spurred by the observation that a few relay nodes with high betweenness centrality can provide more optimal routes for a large number of node pairs, we propose a resilient routing overlay network construction method by introducing Super-Relay nodes. In detail, we present the K-Minimum Spanning Tree with Super-Relay nodes algorithm (SR-KMST), in which we focus on the selection and connection of Super-Relay nodes to optimize the routing quality in a resilient and scalable manner. For the simultaneous path failures between the default physical path and the overlay backup path, we also address the selection of recovery path. The objective is to select a proper one-hop recovery path with minimum cost in path probing and measurement. Simulations based on a real ISP network and a synthetic Internet topology show that our approach can provide high-quality overlay routing service, while achieving good robustness.

• Journal of Construction Engineering and Project Management
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• 제3권3호
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• pp.23-34
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• 2013

As climate change and environmental pollution become one of the biggest global issues today, new renewable energy, especially solar photovoltaic (PV) system, is getting great attention as a sustainable energy source. However, initial investment cost of PV system is considerable, and thus, it is crucial to predict electricity generation accurately before installation of the system. This study analyzes the loss ratio of solar photovoltaic electricity generation from the actual PV system monitoring data to predict electricity generation more accurately in advance. This study is carried out with the following five steps: (i) Data collection of actual electricity generation from PV system and the related information; (ii) Calculation of simulation-based electricity generation; (iii) Comparative analysis between actual electricity generation and simulation-based electricity generation based on the seasonality; (iv) Stochastic approach by defining probability distribution of loss ratio between actual electricity generation and simulation-based electricity generation ; and (v) Case study by conducting Monte-Carlo Simulation (MCS) based on the probability distribution function of loss ratio. The results of this study could be used (i) to estimate electricity generation from PV system more accurately before installation of the system, (ii) to establish the optimal maintenance strategy for the different application fields and the different season, and (iii) to conduct feasibility study on investment at the level of life cycle.

• Advances in concrete construction
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• 제6권1호
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• pp.69-85
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• 2018

In order to provide sufficient stability and resistance against bleeding and segregation during transportation and placing, mineral admixtures are often used in self-compacting concrete mixes (SCC). These fine materials also contribute to reducing the construction cost and the consumption of natural resources. Many studies have confirmed the benefits of these mineral admixtures on properties of SCC in standard curing conditions. However, there are few published reports regarding their effects at elevated curing temperatures. The main objective of this study is to investigate the effect of three different mineral admixtures namely limestone powder (LP), granulated blast furnace slag (GS) and natural pozzolana (PZ) on mechanical properties and porosity of SCC when exposed to different curing temperatures (20, 40, 60 and $80^{\circ}C$). The level of substitution of cement by mineral admixture was fixed at 15%. The results showed that increasing curing temperature causes an improvement in performance at an early age without penalizing its long-term properties. However the temperature of $40^{\circ}C$ is considered the optimal curing temperature to make economical and high performance SCC. On the other hand, GS is the most suitable mineral admixture for SCC under elevated curing temperature.

• 대한토목학회논문집
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• 제36권3호
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• pp.565-571
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• 2016

본 연구에서는 GIS 기반의 오픈 Global Map을 이용하여 공사현장과 토취장의 위치를 확인하고, 덤프와 그레이더 등의 건설장비에 GPS(Global Positioning System)를 부착하여 장비의 실시간 위치, 속도, 고도, 방향등의 Data를 이용하여 실시간 모니터링을 진행하고, Data를 이용하여 생산성 분석을 진행하여 최적 장비 대수를 도출하고 시공단계에서 실시한 설계단가와 모니터링을 통한 장비 생산량으로 도출된 총 경비와 비교한 결과 총 경비 30%정도 적게 나오는 것을 알 수 있었다.

• 동아시아경상학회지
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• 제5권2호
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• pp.1-11
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• 2017

This study attempts to verify effects of CEO' supports, compensation and educational training and those of individual annual salaries and company's sales on promotion of knowledge management expected to contribute to enhancing construction industry's competitiveness, from the perspective of person-organization fit. For the analysis, a total of 368 effective questionnaires were used to conduct independent sample t-test, regression analysis and hierarchical moderated regression analysis. The findings show that individual annual salaries have a positive relationship with company's performance and company's sales also have positive relationships with both knowledge management activities and company performance, and CEO's supports, compensation and educational training are important factors that can improve knowledge management activities. In addition, the principle that the rich get richer and the poor get poorer is also operated in construction industry, as in other industries. Therefore, members in a company should conduct optimal strategies to enhance the knowledge management activities through selection and concentration, while governmental agencies require the establishment of IT system for it and supports for related cost and consulting of it.

• Journal of Information Technology Applications and Management
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• 제9권4호
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• pp.13-34
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• 2002

This paper considers a postal transportation planning problem in the transportation network of the form of hub and spoke Given mail sorting centers and an exchange center, available vehicles and amount of mails to be transported between mail sorting centers, postal transportation planning is to make a transportation plan without violating various restrictions. The objective is to minimize the total transportation cost. To solve the problem, a tabu search algorithm is proposed. The algorithm is composed of a route construction procedure and a route improvement procedure to improve a solution obtained by the route construction procedure using a tabu search. The tabu search uses the best-admissible strategy, BA, and the first-best-admissible strategy, FBA. The algorithm was tested on problems consisting of 11, 16 and 21 mail sorting centers including one exchange center. Solutions of the problems consisting of 11 mail sorting centers including one exchange center were compared with optimal solutions On average, solutions using BA strategy were within 0.287% of the optimum and solutions using FBA strategy were within 0.508% of the optimum. Computational results show that the proposed algorithm can solve practically sized problems within a reasonable time and the quality of the solution is very good.