• 제어로봇시스템학회논문지
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• 제19권7호
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• pp.583-586
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• 2013

We consider discrete-time LTI (Linear Time-Invariant) systems with constant input delays. The input delay is modeled by a first-order PdE (Partial difference Equation) and a backstepping transformation is employed to design a predictor feedback controller. The backstepping approach results in the construction of an explicit Lyapunov function, with which we prove the exponential stability of the closed-loop system formed by the predictor feedback. The numerical example demonstrates the design of the predictor feedback controller, and illustrates the validity of the exponential stability.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.401-406
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• 2012

This paper considers multi-agent systems with interval time-varying delays and switching interconnection topology. By construction of a suitable Lyapunov-Krasovskii's functional, new delay-dependent consensus control conditions for the systems are established in terms of LMIs (Linear Matrix Inequalities) which can be easily solved by various effective optimization algorithms. One numerical example is given to illustrate the effectiveness of the proposed methods.

• Advances in concrete construction
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• 제9권4호
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• pp.407-412
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• 2020

Due to the influence of nonlinearity and time-variation, it is difficult to establish an accurate model of concrete frame structures that adopt active controllers. Fuzzy theory is a relatively appropriate method but susceptible to human subjective experience to decrease the performance. To guarantee the stability of multi-time delays complex system with multi-interconnections, a delay-dependent criterion of evolved design is proposed in this paper. Based on this criterion, the sector nonlinearity which converts the nonlinear model to multiple rule base of the linear model and a new sufficient condition to guarantee the asymptotic stability via Lyapunov function is implemented in terms of linear matrix inequalities (LMI). A numerical simulation for a three-layer reinforced concrete frame structure subjected to earthquakes is demonstrated that the proposed criterion is feasible for practical applications.

• 전기학회논문지
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• 제60권11호
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• pp.2119-2130
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• 2011

This paper proposes new delay-dependent robust stability criteria for neural networks with time-varying delays. By construction of a suitable Lyapunov-Krasovskii's (L-K) functional and use of Finsler's lemma, new stability criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.536-542
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• 2022

Cost overruns, schedule delays, and a shortage of skilled labor are common problems the construction industry is currently experiencing. Modularization and standardization strategies have the potential to resolve the various problems mentioned above and have been applied for various construction applications for a long time. However, the level of modularization remains low, and modular construction projects have not been getting the full benefits. Thus, this review investigated the cutting-edge technologies currently being utilized to develop the modular construction field. For this paper, qualified research papers were identified using predetermined keywords from previous related research papers. Identified literature was then filtered and analyzed. According to the included reviews, several technologies are being developed for modular construction. For example, automated design and monitoring systems for modularization were developed. In addition, research labs are utilizing robotic arms for modular construction to achieve a high level of completion in the construction industry, as is seen in the manufacturing industry. Despite these efforts, more research and development are necessary because some automation technologies still require manual activities. Thus, there is great potential for further development of modularization techniques, and further research is recommended to achieve high levels of modularization.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.399-406
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• 2011

Various construction bonds and warranties critically burden the general contractor. Also, sporadic or cumulative delays of progress payment by the owner can further trap the contractor in a financial quagmire. Facing the possibility of cash flow deficiency and callous response from the banks, most construction firms may become financially incapable of market competition, and attractive project tenders become a bidding game among few deep-pocket players. The downside of such market environment is that the depth of pocket, rather than that of professional competency dictates the choice of market winners. In Taiwan, this has been a potential crisis to the construction industry after the financial crisis which started out since 2008. To encounter this problem, this research will examine the means to better manage the construction industry. Essentially, a credit guarantee system (CGS) is the prime solution to strengthen a bank's confidence in any particular construction firm. Thus establishing a national platform which evaluates and rewards a construction firm's overall credibility is pivotal, and this third-party rated credit can help a bank to render a loan more wisely. Finally, this paper will propose the ideal operating schemes of construction-specific CGS in Taiwan and a credit scoring prototype model for construction industry, as reference for the government and banks, respectively.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.417-422
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• 2020

Vast quantities of environmental pollutants from construction projects are causing significant damage to nearby local communities and thus generate environmental complaints. The construction company, responsible for compensating and resolving environmental complaints, suffers economic damages due to additional expenditures and schedule delays in construction projects. Meanwhile, the construction industry can stagnate from a broader perspective. Therefore, this study aimed to propose a framework for developing an automated management system which consists of two models for environmental complaints in construction projects: (i) the prediction model: a model for predicting environmental complaints based on factors related to environmental complaints; and (ii) the prevention model: a model for providing construction companies with the optimal prevention measure to effectively prevent environmental complaints according to the results of the prediction model. In addition, the algorithm for integrating the developed models into the management system in construction projects was proposed. Eventually, the application of the management system to construction projects can ensure the profitability of construction companies and mitigate damage from environmental pollutants to the nearby local community.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.920-927
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• 2009

Many schedule delays and cost overruns in interior construction are caused by a lack of understanding in detailed and complicated interior works. To minimize these potential impacts in interior construction, a systematic approach for project managers to detect discrepancies at early stages and take corrective action through use of visualized data is required. This systematic implementation is still challenging: monitoring is time-consuming due to the significant amount of as-built data that needs to be collected and evaluated; and current interior construction progress reports have visual limitations in providing spatial context and in representing the complexities of interior components. To overcome these issues, this research focuses on visualization and computer vision techniques representing interior construction progress with photographs. The as-planned 3D models and as-built photographs are visualized in a 3D walk-through model. Within such an environment, the as-built interior construction elements are detected through computer vision techniques to automatically extract the progress data linked with Building Information Modeling (BIM). This allows a comparison between the as-planned model and as-built elements to be used for the representation of interior construction progress by superimposing over a 3D environment. This paper presents the process of representing and detecting interior construction components and the results for an ongoing construction project. This paper discusses implementation and future potential enhancement of these techniques in construction.

• 한국건설관리학회논문집
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• 제22권2호
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• pp.63-71
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• 2021

국내 기업의 해외 건설 수주는 지속적으로 성장하고 양적성장을 이루어왔지만, 2011년 유가하락에 이어 최근 COVID-19의 장기화 등 대외환경의 불확실성이 커지며 해외 건설 시장의 침체가 전망된다. 이에 4차 산업혁명의 발전된 기술을 활용해 그간 축적된 데이터를 연구한다면, 향후 해외 건설사업 관리의 역량 및 경쟁력을 키울 수 있을 것이다. 따라서 이 연구에서는 중동 건설시장에서 공정지연과 주요 분쟁의 원인으로 대두되고 있는 공사변경의 상향된 프로젝트 관리 방안을 제시하고자 하였다. 우선 실제 해외 플랜트 건설사례를 분석하여 6가지 주요 공사변경 원인을 도출하였고, 이에 따라 영향을 받는 요인을 8가지로 분류하였다. 특히 머신러닝 기반의 다양한 Feature Selection 기법을 활용해 중요도를 계량화된 수치를 평가함으로써 공사변경과 영향 요인 사이의 유의미한 관계를 파악 하였다. 이를 통해 프로젝트 관리 측면에서 내부적으로는 공사변경의 명확한 관리 방향 수립이 가능하고, 대외적으로는 협상 기간 단축으로 추가적인 공기 지연을 방지하고 비용지출 관리가 가능할 것이라고 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.301-302
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• 2012

Recently, high-rise building projects have been in the spotlight in South Korea. Curtain wall construction, as one of important operations in the high-rise building projects is composed of various, entangled and complex unit processes that require a systematic planning to prevent unexpected delays. A schedule simulation technique has been used for deriving more efficient planning and accurate performance measurement. However, the simulation technique has difficulty in collecting actual data and in applying data fluctuations during construction. Thus, this paper suggests a concept model of Modular Simulation Model(MSM) that overcomes such limitations of traditional simulation technique based on curtain wall operations.