• 한국건설관리학회논문집
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• 제16권2호
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• pp.21-28
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• 2015

공사비 증가와 공기 지연 등 건설프로젝트에 악영향을 미치는 건설품질결함은 지속적으로 발생하고 있다. 그간 결함을 유발시키는 원인들을 규명하기 위한 연구는 다수 있었으나, 원인들 간의 상관관계를 분석한 연구는 충분히 이루어지지 않았다. 본 논문에서는 국내 30개 프로젝트에서 발생한 1,241건의 부적합 사례 중 831건의 건축공종 부적합 사례를 토대로 건설품질결함의 발생요인을 발생단계, 발생현상, 기인원인, 처리방안으로 나누어 이들 간의 상관관계를 분석하고자 한다. 상관분석을 통해 부적합은 주로 조달 및 시공단계에서 기능결함 및 시공결함의 형태로 발생함을 알 수 있었다. 주로 작업자의 실수, 조악한 품질의 자재사용, 그리고 잘못된 시공방법에 의해 발생되는 품질결함은 주로 특채, 수리, 재작업의 방법으로 처리되어 공사비 증가 및 공기 지연을 가져옴을 알 수 있었다. 본 논문은 향후 품질결함의 발생과정을 규명하고 효율적인 품질결함 방지대책을 수립하는 데에 있어 중요한 이론적 배경과 정량적 지표를 제공했다는 데 그 의의가 있다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.222-232
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• 2024

New modular factory-built methodologies implemented in the construction and industrial plant industries may bring down costs for modular reactors. A factory-built environment brings about benefits such as; improved equipment, tools, quality, shift patterns, training, continuous improvement learning, environmental control, standardisation, parallel working, the use of commercial off shelf equipment and much of the commissioning can be completed before leaving the factory. All these benefits combine to reduce build schedules, increase certainty, reduce risk and make financing easier and cheaper.Currently, the construction and industrial chemical plant industries have implemented successful modular design and construction techniques. Therefore, the objectives of this paper are to understand and analyse the state of the art research in these industries through a systematic literature review. The research can then be assessed and applied to modular reactors.The literature review highlighted analysis methods that may prove to be useful. These include; modularisation decision tools, stakeholder analysis, schedule, supply chain, logistics, module design tools and construction site planning. Applicable research was highlighted for further work exploration for designers to assess, develop and efficiently design their modular reactors.

• 경영과학
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• 제11권3호
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• pp.129-151
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• 1994

This paper focuses on method of setting priorities for telecommunications Standardization in which usually includes prioritization, resource allocation, standardization schedule for each SWA is based on prioritization of SWAs. We mainly used the Analytic Hierarchy Process(AHP) and a modified Delphi technique as a method for planning process. Recently, rapid technology evolution in telecommunications fields increases the necessity of developing more and more new standards. Also increased complexity of technologies makes standards more complicated, more specified and more thick than the past ones. As a result, the number of SWAa(Standardization Work Areas) and SWIs(Standardization Work Iterms) is being increased continuously. Furthermore, rapid telecommunication environment changes such as deregulation, liberalization, privatization, regionalization, and globalization surrounding telecommunications standardization grows increasingly important. To cope with these challenges and to make the more efficient use of the limited standardization resources, i.e., time, financial, personal resources, we will suggest logical and rational approach that is a backbone of strategic plan for telecommunication standardization. The telecommunication standardization planning process involves a MCDM(Multi-Criteria Decision Making) process. The Analytic Hierarchy Process(AHP) is a kind of MCDM approach. Our method is based on a combination of a modified Delphi technique and an application of AHP(spreadsheet model). Analyzed data from Delphi technique is used as inputs to AHP. In addition we also focus on the technique how to combine group judgments and to handle a large number of comparisons.

• ETRI Journal
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• 제39권3호
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• pp.353-363
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• 2017

Recently, sink mobility has been shown to be highly beneficial in improving network lifetime in wireless sensor networks (WSNs). Numerous studies have exploited mobile sinks (MSs) to collect sensed data in order to improve energy efficiency and reduce WSN operational costs. However, there have been few studies on the effectiveness of MS operation on WSN closed operating cycles. Therefore, it is important to investigate how data is collected and how to plan the trajectory of the MS in order to gather data in time, reduce energy consumption, and improve WSN network lifetime. In this study, we combine two methods, the cluster-head election algorithm and the MS trajectory optimization algorithm, to propose the optimal MS movement strategy. This study aims to provide a closed operating cycle for WSNs, by which the energy consumption and running time of a WSN is minimized during the cluster election and data gathering periods. Furthermore, our flexible MS movement scenarios achieve both a long network lifetime and an optimal MS schedule. The simulation results demonstrate that our proposed algorithm achieves better performance than other well-known algorithms.

• 인터넷정보학회논문지
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• 제19권2호
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• pp.33-41
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• 2018

In recent years, technology is rapidly changing to support new service consumption and distribution models in multimedia service systems and hybrid delivery of media services is a key factor for enabling next generation multimedia services. This phenomenon can lead to rapidly increasing network traffic and ultimately has a direct and aggravating effect on the user's quality of service (QOS). To address the issue, we propose a novel system architecture to provide smart hybrid media services efficiently. The architecture is designed to apply the software-defined networking (SDN) method, detect changes in traffic, and combine the data, including user data, service features, and computation node status, to provide a service schedule that is suitable for the current state. To this end, the proposed architecture is based on 2-level scheduling, where Level-1 scheduling is responsible for the best network path and a computation node for processing the user request, whereas Level-2 scheduling deals with individual service requests that arrived at the computation node. This paper describes the overall concept of the architecture, as well as the functions of each component. In addition, this paper describes potential scenarios that demonstrate how this architecture could provide services more efficiently than current media-service architectures.

• 한국건설관리학회논문집
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• 제8권4호
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• pp.203-213
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• 2007

In the past, several construction projects have exceeded their schedule resulting in financial losses to the owners; at present there are very few methods available to accurately forecast the completion date of a project. These nay be because of unforeseen outcomes that cannot be accounted for earlier and because of deficiency of proper tools to forecast completion date of said project. To overcome these difficulties, project managers may need a tool to predict the completion date at the early stage of project development. Bayesian Inference introduced in this paper is one such tool that can be employed to forecast project progress at all construction stages. Using this inference, project managers can combine an initially planned project progress (growth curve) with reported information from ongoing projects during the development, and in addition, dynamically revise this initial plan and quantify the uncertainty of completion date. This study introduces a theoretical model and proposes a mathematically information-based framework to forecast a project completion date that corresponds with the actual progress data and to monitor the modified uncertainties using Bayesian Inference.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.113-119
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• 2018

Occupancy-based heating control is effective in reducing heating energy by preventing unnecessary heating during unoccupied period. Various technologies on detecting human occupancy have been developed using complicated machine learning algorithm and stochastic methodologies. This study aims at deriving low-cost and simple algorithm of occupancy inference that can be implemented to residential buildings. The core concept of the algorithm is to combine the occupancy probabilities based on indoor CO2 concentration and PIR(passive infrared) signals. The probability was estimated by applying different levels of decrement ratio depending on CO2 concentration change rate and aggregated PIR signals. The developed algorithm was validated by comparing the inference results with the occupancy schedule in a real residential building. The results showed that the inference algorithm can achieve the accuracy of 75~99%, which would be successfully implemented to the control of residential heating systems.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.627-628
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• 2015

Construction defect which can causes economic damage such as schedule delay, cost overrun is a considerably important factor in construction industry. In general, a construction defect features a difficulty to find out causes precisely because it occurs when several interrelated causes combine. Yet, studies have tried to understand the interrelationships between factors are limited. In addition, despite of a tremendous amount of construction data, it's not still enough to analyze them, but tends to depend on experience or know-how of practitioners. Thus, it is necessary to identify underlying causes in influential factors by utilizing related data. This paper analyses Interrelationships between causal factors using Association Rule Mining to discover root causes of construction defects. Confidence and Lift that can be used for presenting the interrelationships of the causes were extracted from 1241 cases in 30 projects in Korea. It is expected that this paper allows the construction managers to discover key factors and make right decisions to reduce occurrence of construction defects. Furthermore, analysis of interrelationships can improve understanding of structural patterns of construction defects.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.78-83
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• 2011

본 논문에서는 DVB-S2 기반 LDPC 부호의 반복 복호횟수를 줄이기 위한 계산 복잡도가 줄어든 early stopping 방식을 제안한다. DVB-S2 기반 LDPC 복호기는 최대 64800 비트의 부호를 처리해야 되기 때문에 그 자체로 매우 높은 계산 복잡도를 가진다. 기존 early stopping 방식은 64800 비트의 DVB-S2 LDPC 코드를 이용하여 early stopping 기준치를 계산하는데 있어 높은 계산 복잡도를 가진다. 따라서 제안 방식은 LDPC 부호의 계층적 복호방식중 하나인 Horizontal Shuffling Scheduling 복호 방식에 early stopping 방식을 간단하게 적용함으로써 기존 방식 대비 최대 70%의 계산량 감소를 달성하였다. 실험 결과는 제안 방식을 적용한 LDPC 복호 알고리즘이 기존 방식 대비 Bit Error Rate 성능이 더 우수하다는 것을 보여준다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.847-864
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• 1995

In this paper we present an integrated methodology for strategic planning in telecommunications standardization. Especially this paper focuses on the method of setting priorities for telecommunications SWAs(Standardization Work Areas) and related SWls(Standardization Work Items). To make a strategic plan for telecommunications standardization in which usually includes prioritization, resource allocation, standardization schedule for each SWA is based on prioritization of SWAs. Our methodology integrated various existing methods including the Analytic Hierarchy Process(AHP) and a modified Delphi technique. Recently, rapid technology evolution in telecommunications fields increases the necessity of developing more and more new standards. Also increased complexity of those technologies makes standards more complicated, more specified and more thick than the past ones. As a result, the number of SWAs and SWIs are being increased constantly. Furthermore, rapid telecommunication environment changes such as deregulation, liberalization, privatization, regionalization, and globalization surrounding standardization bring about new challenges and opportunities. Due to all these trends, strategic planning for telecommunications standardization grows more and more important. To cope with these challenges and also to make the more efficient use of the limited standardization resources including time, financial, human resources, we suggest more logical and rational approach that will be a backbone of strategic plan for telecommunications standardization. The telecommunications standardization planning process involves a MCDM(Multi-Criteria Decision Making) process. The Analytic Hierarchy Process(AHP) is a kind of MCDM approaches. Our method is based on a combination of a modified Delphi technique and an application of AHP(Liberator's spreadsheet model). Analyzed data from Delphi technique is used as inputs to ABP. In addition, we also focus on the technique how to combine group judgments and to handle a large number of comparisons. We present analyzed results including Pilot and Full Scale Survey according to the proposed process. The result of this study will be useful input for telecommunications standardization policy making and practical implementation.