• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.469-474
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• 2008

In the last decade many advanced home network services have been provided by construction industry, and many researches on the area have been carried out. One of the problems we are confronted with is that we do not have a standard classification scheme for home network services yet. In this paper a more stable classification scheme is suggested after comparative analysis of many different schemes in previous researches. More commonly highly attended service categories in the scheme is selected, and those are examined in terms of how commonly they are supplied by construction industry. In the later part of this paper the current home network building certification code is reviewed if the code complies with the highly attended categories in the classification scheme suggested in this paper. Some ideas to improve the current certification code is suggested by adding or optionally adding the highly attended categories.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.248-251
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• 2002

The cooperative relation between construction engineering firms and design subcontractors is essential to establish design collaboration system. So, this study is initiated with providing a strategic cooperation scheme between construction engineering firms and design subcontractors. A number of literatures related to the design process for engineering firms were reviewed in order to investigate the design collaboration system. A questionnaire survey was peformed to collect and analyze the expert opinion on the current design collaboration system for engineering firms. It is expected that the cooperation scheme can be utilized to improve the cooperative relation between construction engineering firms and design subcontractors.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.299-302
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• 2003

Recently the timely delivery and the appropriate management for construction materials are of great significance in that the buildings are getting complicated and more various materials need to be handled. However, these systems have some problems, and do not seem to work effectively yet. The reason is that the lack of operation scheme for systematic management in project. In this study the efficient scheme for the .material procurement system in construction firms to manage the construction materials efficiently was discussed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.397-400
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• 2002

The purpose of this study is to analyze current status and propose improvement scheme of safety management on the heavy construction equipment operation. The research method invloves interview and questionnaire survey for the analysis of practical use status of heavy construction equipment. The results of this study are as fallows: 1) The problem of safety management status on heavy construction equipment operation is surveyed not wearing safety helmet, not keeping work regulations, and not preparing the work before start. 2) Proposed improvement scheme of safety management on heavy construction equipment operation includes strengthening 5 minutes safety education before start, strengthening safety action against falling materials, and strengthening enough preparation before start.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1513-1525
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• 2016

Rapid and accurate phase synchronization is critical for the reliable control of grid-tied inverters. However, the commonly used software phase-locked loop methods do not always satisfy the need for high-speed and accurate phase synchronization under severe grid imbalance conditions. To address this problem, this study develops a novel open-loop phase locking scheme based on a synchronous reference frame. The proposed scheme is characterized by remarkable response speed, high accuracy, and easy implementation. It comprises three functional cascaded blocks: fast orthogonal signal generation block, fast fundamental-frequency positive sequence component construction block, and fast phase calculation block. The developed virtual orthogonal signal generation method in the first block, which is characterized by noise immunity and high accuracy, can effectively avoid approximation errors and noise amplification in a wide range of sampling frequencies. In the second block, which is the foundation for achieving fast phase synchronization within 3 ms, the fundamental-frequency positive sequence components of unsymmetrical grid voltages can be achieved with the developed orthogonal signal construction strategy and the symmetrical component method. The real-time grid phase can be consequently obtained in the third block, which is free from self-tuning closed-loop control and thus improves the dynamic performance of the proposed scheme. The proposed scheme is adaptive to severe unsymmetrical grid voltages with sudden changes in magnitude, phase, and/or frequency. Moreover, this scheme is able to eliminate phase errors induced by harmonics and random noise. The validity and utility of the proposed scheme are verified by the experimental results.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.3
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• pp.37-48
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• 2000

서울Visual cryptography scheme is a simple method in which can be directly decoded the secret information in human visual system without performing any cryptographic computations. This scheme is a kind of secret sharing scheme in which if a secret of image type is scattered to n random images(slides) and any threshold (or more) of them are stacked together the original image will become visible. In this paper we consider (2, n) visual cryptography scheme and propose a new construction method in which the number of expanded pixels can be reduced by using the sample matrix. The proposed scheme can futhermore distribute the multiple secret image to each group according to the difference of relative contrast.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.587-590
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• 2005

This study investigates the efficient construction scheme of the immersed tunnel focusing on the hydration heat. In this respect, some alternatives in curing, temperature condition and removing of the forms are compared together to meet the required criteria. It is addressed that the strict construction stage analysis considering the placing scheme of concrete is one of the key factors to trace the realistic structural behavior for the hydration heat.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1001-1006
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• 2000

These should be constructed partially, because many prestressed concrete box girder bridges in situ have large cross section and long span. Therefore, accurate prediction of differences, both elapse time of each construction stage and exposure of atmosphere at each position of cross section, is very important. Though it is importance, engineers are apt to overlook it. This study predicted cracks due to shrinkage and stress concentration phenomenon by each construction stage and then, ascertained reduction of tensile stresses after applying retrofit scheme.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.942-948
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• 2009

Today's construction is a large-scale and long life span program, so called Mega-scale project, that every moment constructor faces much of hardships, It is because of a large amount of stakeholders, data and complicated relationship among workers. In order to overcome these problems, IETM(Interactive Electronic Technical Manual) has been introduced to construction industry recently, It is regarded as a useful tool for handling the data, procedures of the construction, but it is similar to existing IT-based information systems, the PMIS(Project Management Information System) and the KMS(Knowledge Management System), without characterizing. This research is intended to find out IETM's property and to present the Ontology scheme discriminating Construction IETM from existing systems..

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.53-59
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• 2009

As a special type of Wireless Ad Hoc Networks, Wireless Mesh Networks (WMNs) have become the comer stone of research issues. Due to the limited operational environment of WMNs, an efficient connected dominating set (CDS) construction scheme is an important concern since it has been found extremely useful in broadcasting, routing and virtual backbone construction. In this paper, we propose a distributed Bandwidth-Interference aware CDS construction scheme to improve the network performance via two parameters such as node's number of neighbor and link bandwidth. Our CDS construction scheme selects the node that has more neighbors and enough bandwidth to support more end-devices in order to enhance overall network throughput and reliability. We confirm through simulations and show that our scheme constructs the CDS with the small subset of DS and the link that has better bandwidth.