• ETRI Journal
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• 제43권2호
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• pp.357-370
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• 2021

The evolution of blockchain-based systems has enabled researchers to develop nextgeneration e-voting systems. However, the classical consensus method of blockchain, that is, Proof-of-Work, as implemented in Bitcoin, has a significant impact on energy consumption and compromises the scalability, efficiency, and latency of the system. In this paper, we propose a hybrid consensus model (PSC-Bchain) composed of Proof of Credibility and Proof of Stake that work mutually to address the aforementioned problems to secure e-voting systems. Smart contracts are used to provide a trustworthy public bulletin board and a secure computing environment to ensure the accuracy of the ballot outcome. We combine a sharding mechanism with the PSC-Bchain hybrid approach to emphasize security, thus enhancing the scalability and performance of the blockchain-based e-voting system. Furthermore, we compare and discuss the execution of attacks on the classical blockchain and our proposed hybrid blockchain, and analyze the security. Our experiments yielded new observations on the overall security, performance, and scalability of blockchain-based e-voting systems.

• 한국정보시스템학회지:정보시스템연구
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• 제30권2호
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• pp.105-126
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• 2021

Purpose The purpose of this study is to implement a optimal machine learning model about the cancellation prediction performance in car sales business. It is to apply the data set of accumulated contract, cancellation, and sales information in sales support system(SFA) which is commonly used for sales, customers and inventory management by imported car dealers, to several machine learning models and predict performance of cancellation. Design/methodology/approach This study extracts 29,073 contracts, cancellations, and sales data from 2015 to 2020 accumulated in the sales support system(SFA) for imported car dealers and uses the analysis program Python Jupiter notebook in order to perform data pre-processing, verification, and modeling that is applying and learning to Machine learning model after then the final result was predicted using new data. Findings This study confirmed that cancellation prediction is possible by applying car purchase contract information to machine learning models. It proved the possibility of developing and utilizing a generalized predictive model by using data of imported car sales system with machine learning technology. It can reduce and prevent the sales failure as caring the potential lost customer intensively and it lead to increase sales revenue by predicting the cancellation possibility of individual customers.

• Journal of Information Processing Systems
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• 제19권2호
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• pp.240-257
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• 2023

The industrial Internet of Things (IIoT) is characterized by intelligent connection, real-time data processing, collaborative monitoring, and automatic information processing. The heterogeneous IIoT devices require a high data rate, high reliability, high coverage, and low delay, thus posing a significant challenge to information security. High-performance edge and cloud servers are a good backup solution for IIoT devices with limited capabilities. However, privacy leakage and network attack cases may occur in heterogeneous IIoT environments. Cloud-based multi-party computing is a reliable privacy-protecting technology that encourages multiparty participation in joint computing without privacy disclosure. However, the default cloud selection method does not meet the heterogeneous IIoT requirements. The server can be dishonest, significantly increasing the probability of multi-party computation failure or inefficiency. This paper proposes a blockchain and smart contract-based optimized cloud node selection framework. Different participants choose the best server that meets their performance demands, considering the communication delay. Smart contracts provide a progressive request mechanism to increase participation. The simulation results show that our framework improves overall multi-party computing efficiency by up to 44.73%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.219-220
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• 2022

In order to meet the trend, construction public data are already disclosing not only data generated at the construction site but also various data ranging from inspection reports and public construction contracts through multiple portals. However, unlike the excellence of the open performance evaluated by the number of data, it is difficult to evaluate the specific level of disclosure because there is no case of analyzing the quality, ease of use, and possibility of further opening of the public construction data set. On the other hand, performance measurement is already performed using an internationally agreed evaluation method in different fields such as real estate, population, and environment. So it is essential to analyze the current status of public data openings in the construction field and to derive improvement tasks. Therefore, this study conducted a survey of researchers with the highest system utilization targeting representative public data open systems in the construction field, such as E-AIS(세움터) and KISCON. To ensure fairness and increase comparability, the questionnaire was composed using evaluation items on implementing public data conducted annually by the World Wide Web Foundation, an international non-profit organization. With these responses, we investigated the status of public data disclosure and opinions on data quality and derived tasks to improve public data disclosure in construction through the analysis of the results.

• 유통과학연구
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• 제22권1호
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• pp.95-103
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• 2024

Purpose: Focusing on the complex supply chain operations beyond the simple dyadic relationship, this study evaluates the performance of the revenue sharing contract in three stage supply chain system. Research design, data, and methodology: The optimization model is developed to describe the supply chain system where one manufacturer, one wholesaler, and one retailer exist and pursue the maximum level of their own profits. In the numerical examples of the proposed supply chain model, two types of the revenue sharing contract, pairwise and spanning methods, are tested and their performances are compared with the traditional system. Results: The numerical analysis reveals that both types of the revenue sharing contract outperform the traditional system. All supply chain members can achieve the improved profits only when they determine the proper combination of revenue share ratios and price discount rates. Conclusions: This study finds out that both pairwise and spanning revenue sharing contracts can make the positive outcome that is acceptable to all members in three stage supply chain system. When the proper contract content is agreed among the supply chain members, the revenue sharing contract has the potential to be the practically feasible collaboration program for the multiple stage supply chain system.

• 한국컴퓨터정보학회논문지
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• 제25권5호
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• pp.217-227
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• 2020

본 연구는 물류 기업이 블록체인기술을 채택하는 데 어떠한 요인들이 영향을 미치는가를 파악하고 블록체인기술이 물류성과에 미치는 영향을 분석하는 것을 연구목적으로 하고 있다. 블록체인기술의 채택에 영향을 미치는 변수들은 TOE 프레임을 바탕으로 제시하였다. 블록체인기술 채택 요인으로 기대이익, 조직준비성, 기술호환성, 경쟁압력을 제시하였다. 그리고 블록체인기술로는 스마트 계약과 정보 투명성을 제시하였다. 물류성과는 신속성과 조정성을 제시하였다. 한국의 물류 기업을 대상으로 설문조사를 실시하였다. 수집된 자료를 분석한 결과를 보면 기대이익, 기술호환성은 블록체인기술(스마트 계약, 정보 투명성)에 정의 영향을 미치는 것으로 나타났다. 조직준비성은 정보투명성에 정의 영향을 미치는 것으로 나타났다. 블록체인기술은 물류성과에 정의 영향을 미치는 것으로 나타났다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.41-47
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• 2007

최적 발주방식을 선정하는 것은 해당 사업의 성공적 수행을 위한 것이며, 이는 곧 사업의 목표를 달성시키는 것이다. 또한 사업특성에 적합한 발주방식의 선정과 사업의 성과는 밀접한 연관성을 갖는다. 이러한 취지에서 재정경제부는 2007년 10월 국가계약법시행령 개정을 통해 "기술제안입찰", "설계공모${\cdot}$기술제안입찰"이라는 발주제도를 새로이 도입하였다. 다양해진 발주제도를 효율적으로 운영할 수 있도록 하기 위해 본 연구는 공공건설사업의 특성을 정량적, 정성적으로 평가하여 해당 사업에 가장 적합한 발주방식을 선정할 수 있도록 하는 발주방식 선정모델을 제시하였다. 그리고 발주방식 성과평가 모델을 함께 제시하여 발주방식 선정 및 운영의 결과를 후속 사업의 피드백 할 수 있도록 하였다. 이와 같은 표준적인 모델은 공공발주기관의 의사결정을 지원하는 도구로 활용될 수 있을 것이다.

• 한국건설관리학회논문집
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• 제8권2호
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• pp.155-163
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• 2007

건설프로젝트를 수행하는 과정에 있어 계약당사자간에 다양한 계약방식에 기초하여 시설물 건설에 요구되는 업무 또는 서비스를 제공하고 있으나, 건설사업의 주요 성과지표라 할 수 있는 비용, 일정, 안전등의 측면에서 계약방식에 따라 발생할 수 있는 성과의 차이에 대한 실증적 인 비교연구는 미흡한 실정이다. 건설사업이 다수의 건설전문조직과 계약을 기반으로 운영되는 프로젝트라는 특성을 고려할 때 계약방식의 유형에 따라 사업성과에 대한 차이를 비교분석 함으로써 계약방식 선정에 대한 적정 의사결정을 지원하는데 유효한 자료를 제공할 수 있다. 이에 본 연구에서는 건설계약방식 중 실비정산방식과 총액계약방식을 대상으로 건설사업의 주요 성과에 대한 비교 분석을 시도하였다. 계약방식별 프로젝트 성과는 미국 Construction Industry Institute(CII)의 Benchmarking and Metrics(BM&M) 프로그램에서 활용하는 성과측정기준을 기초로 비용, 공정, 안전, 변경, 재작업(rework) 등 5개 분야를 대상으로 하였다. 또한 계약방식으로 인한 각종 성과지표의 차이가 통계적 의미를 지니고 있는가를 판단하기 위하여 통계적 기법인 t-test를 이용하여 데이터의 유의성을 분석하였다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.289-298
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• 2007

The development of construction industry has led to the increase in the number of criteria imposed by project clients for selecting contractors. For example, clients often request tenderers to satisfy various conditions such as tight programme, financial strength, managerial ability, relevant work experiences, technical strength, high workmanship standard, safety requirement, quality specification, and yet others. This trend has attracted research interests of devising various methods for helping project clients to assess contractors' bids. For example, in recent development, the Works Bureau of the Hong Kong Government has introduced two mechanisms in tender evaluation for various public work contracts, namely, the Marking Scheme effective from June 2002 and the Formula Approach effective from November 2002 [1], [2]. These approaches evaluate a contractor's tender by considering collectively its tender price and performance attributes, the latter including contractor experience, past performance, technical resources and technical content of his proposal. The tender with the highest combined price and performance score (CPPS) will be normally recommended for acceptance. It appears, however, that there is little existing research in helping contractors to identify a competition strategy that enables the contractor to offer his most competitive bid collectively taking into account his resource capacities and project client's multiple performance criteria. This paper examines the factors affecting contractor's competition strategy to compete for works in Hong Kong. The understanding about the factors will contribute to identifying effective competition strategy. The data used for the analysis were collected from Hong Kong construction industry. The research findings may provide valuable references for investigating effective competition strategies in other construction industries outside the region.

• 디지털융복합연구
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• 제11권7호
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• pp.83-95
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• 2013

엔지니어링 프로젝트의 공급망관리는 입찰 및 수주, 협력업체의 선정, 계약체결부터 시작하여 프로젝트 진행을 위한 협력업체와의 협업 등 다양한 활동을 포함한다. 본 연구의 목적은 프로젝트 유형의 공급망에 참여한 바 있는 협력업체들의 공급망 관련 성과를 최종 종속요인으로 설정하고, 흡수능력, 협력업체 평가의 공정성, 협업의 질 및 인센티브 등과 같은 주요 선행요인 간의 상호연관관계를 분석하는데 있다. 이를 위해 프로젝트 공급망에의 참여실적이 있는 기업들로부터 설문조사를 실시하여 통계적 가설을 검증하였다. 분석결과, 협력업체들의 공급망 성과는 인센티브, 흡수능력 및 협업의 질에 의해 영향을 받으며, 협력업체 평가공정성은 인센티브와 흡수능력에도 영향을 미침을 확인할 수 있었다. 다만 인센티브는 유의수준 5%에서 흡수능력 증대에 영향을 미치지 못한다는 통계적 결과가 도출되었다.