• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.609-623
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• 2010

In this paper the feedback loop mechanisms that are inherent in the management of water supply systems were identified based on the system dynamics modeling methodology. As a result, a system dynamics (SD) computer simulation model that can be used to aid efficient management of water supply systems was developed. The developed SD model can be used to predict operating conditions of water supply systems including the effects of pipe maintenance on the entire system. The developed model is consisted of water supply, pipe maintenance and water supply business finance model. The operation and maintenance data from a study water supply system were used to verify the model and to predict the past and future operating conditions of the system. The policy leverage that greatly affects the operating condition was evaluated by the sensitivity analyses for the operational indices due to changes in the exogenous variables. It was found that while the pipe maintenance related exogenous variables had great effects on the leakage and conditions of pipes, they did not have great effects on the major operational indices such as revenue water ratio. It is considered that the social costs due to leaks and pipe breaks and the corresponding mechanism of propagation of the costs must be modeled to better evaluate the effects of pipe maintenance on the operational conditions of water supply systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.30-37
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• 2007

An exponentiation in $GF(2^m)$ is a basic operation for several algorithms used in cryptography, digital signal processing, error-correction code and so on. Existing hardware implementations for the exponentiation operation organize by Right-to-Left method since a merit of parallel circuit. Our paper proposes a polynomial exponentiation structure with a trinomial that is organized by Left-to-Right method and that utilizes a weakly dual basis. The basic idea of our method is to decrease time delay using precomputation tables because one of two inputs in the Left-to-Right method is fixed. Since $T_{sqr}$ (squarer time delay) + $T_{mul}$(multiplier time delay) of ow method is smaller than $T_{mul}$ of existing methods, our method reduces time delays of existing Left-to-Right and Right-to-Left methods by each 17%, 10% for $x^m+x+1$ (irreducible polynomial), by each 21%, 9% $x^m+x^k+1(1, by each 15%, 1% for $x^m+x^{m/2}+1$.

• Journal of Internet Computing and Services
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• v.15 no.4
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• pp.125-133
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• 2014

The column-oriented database storage is a very advanced model for large-volume data analysis systems because of its superior I/O performance. Traditional data storages exploit row-oriented storage where the attributes of a record are placed contiguously in hard disk for fast write operations. However, for search-mostly datawarehouse systems, column-oriented storage has become a more proper model because of its superior read performance. Recently, solid state drive using MLC flash memory is largely recognized as the preferred storage media for high-speed data analysis systems. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major storage components of modern database servers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of column compression and flash operation as compared to RAM memory. In this research, we propose a new scheme called Column-aware Multi-Version Locking (CaMVL) scheme for efficient transaction processing. CaMVL improves transaction performance by using compression lock and multi version reads for efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of CaMVL. Based on the results of the performance evaluation, we conclude that CaMVL scheme outperforms the traditional scheme.

• Korean Journal of Construction Engineering and Management
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• v.20 no.6
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• pp.3-10
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• 2019

The entire duration of the long-term continuous construction contract project cannot be expected when calculating the initial budget as the construction of the contract is carried out annually according to the budget composition. In addition, the statutes related to the defect liability and execution of contracts have not been established systematically in relation to the contract. Therefore, there are many problems at the actual construction site with regard to the defect liability or the performance of the contract in relation to the contract. In this study, the following improvement directions were presented for the efficient operation of the contracts: First, the defect liability is legal and should be specified in an Act rather than an enforcement decree. Second, if the parties to the contract vary in the following order in the contract, the special agreement should be specified in the enforcement decree. Third, in the event of an indirect cost due to the extension of the period of the long-term continuous work, the contingency items of the total project cost management policy should be utilized. Fourth, in the case of general construction contract conditions, clauses related to the purchase of the premium of the CAR, inspection, taking over, defect repair, and defect inspection shall be supplemented.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.15-26
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• 2019

This study was to explore the domestic research trends, and education and operation cases concerned with Korean colleges in the fourth industrial revolution era. It was conducted through the analysis of 114 academic papers registered to the Korea Research Foundation, the newspaper articles, and the main 4-year university homepage from 2016 to April 2019. The results was as follows. Research papers have been increasing since 2016; research were conducted by humanities and social sciences as well as engineering academics interesting in research topics such as technologies, curriculum, and teaching and learning by mainly using quantitative research, literature research. As for the college education, reorganization of the undergraduate and majors centered on the science and engineering field, teaching and learning related with learner's participation and performance, and provide efficient academic affairs management and career guidance using Chatbot or Cloud computing. Industry-academia cooperation was focuses on the field of science and engineering. In future research, it is necessary to explore the research on college students' career and employment, the research on academic affairs management and infrastructure, the relational research considering the variables among college students and faculties, and the qualitative and mixed method approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1198-1212
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• 2013

Network virtualization enables autonomous and heterogeneous Virtual Networks (VNs) to co-exist on a shared physical substrate. In a Network Virtualization Environment (NVE), the fact that individual VNs are underpinned by diverse naming mechanisms brings about an obvious challenge for transparent communication across multiple VN domains due to the complexity of uniquely identifying users. Existing solutions were mainly proposed compatible to Internet paradigm with little consideration of their applications in a virtualized environment. This calls for a scalable and efficient naming framework to enable consistent communication across a large user population (fixed or mobile) hosted by multiple VNs. This paper highlights the underlying technical requirements and presents a scalable Global Naming Framework (GNF), which (1) enables transparent communication across multiple VNs owned by the same or different SPs; (2) supports communication in the presence of dynamics induced from both VN and end users; and (3) greatly reduces the network operational complexity (space and time). The suggested approach is assessed through extensive simulation experiments for a range of network scenarios. The numerical result clearly verifies its effectiveness and scalability which enables its application in a large-scale NVE without significant deployment and management hurdles.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.2
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• pp.97-111
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• 2015

In this paper, a methodology for effectively treating daily waste at D metropolitan city is considered using reverse logistics(RL) network. Currently, eight district offices at D metropolitan city are treating their daily wastes using each RL network. However, unfortunately, current method has a weakness such as inefficiency of RL network operation. Therefore, we propose a revised method for improving the inefficiency. In case study, we compare the performances of the current and revised methods using various real-life data. The analysis result shows that the revised method outperforms the current method.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.175-197
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• 2012

The art museums in South Korea are mostly small-scaled institutions with small amount of art works. Thus, internationally accepted metadata standards such as CDWA and VRA Core may not be efficient to manage their collections. Because of these distinct local characteristics, there is a need to create a set of metadata elements that can be used for the art museum community in the country. This research aims to propose a set of metadata elements customized to fit into the context of small-scaled art museums in South Korea. The construction of the element set was not from scratch but on the basis of existing standards such as CDWA, VRA Core, and Dublin Core. By identifying core elements that are indispensable in describing art works and collecting opinions of experts in art museums, the proposed set of metadata elements is expected to support the operation and management of art works and satisfy the localized needs of the art museum community.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.57-62
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• 2005

Microarray gene expression profiling technology is one of the most important research topics in clinical diagnosis of disease. Given thousands of genes, only a small number of them show strong correlation with a certain phenotype. To identify such an optimal subset from thousands of genes is intractable, which plays a crucial role when classify multiple-class genes express models from tumor samples. This paper proposes an efficient classifier design method to simultaneously select the most relevant genes using an intelligent genetic algorithm (IGA) and design an accurate classifier using Support Vector Machine (SVM). IGA with an intelligent crossover operation based on orthogonal experimental design can efficiently solve large-scale parameter optimization problems. Therefore, the parameters of SVM as well as the binary parameters for gene selection are all encoded in a chromosome to achieve simultaneous optimization of gene selection and the associated SVM for accurate tumor classification. The effectiveness of the proposed method IGA/SVM is evaluated using four benchmark datasets. It is shown by computer simulation that IGA/SVM performs better than the existing method in terms of classification accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.581-584
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.