• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.80-89
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• 2009

A DHT(Distributed Hash Table) based P2P is a method that compensates disadvantages of the existing unstructured P2P method. If a DHT algorithm is used, it can do fast data search and maintain search efficiency independent of the number of peers. The peers in a DHT method send messages periodically to keep the routing table updated. In a mobile environment, the peers in a DHT method should send messages more frequently to keep the routing table updated and reduce the failure of requests. However this results in increasing the overall network traffic. In this paper, we propose a method to reduce the update load of a routing table in the existing DHT by updating it in a reactive way. In the proposed reactive method, a routing table is updated only if a data request is coming whereas it is updated periodically in the existing proactive method. We perform experiments using Chord simulator(I3) made by UC Berkely. The experimental results show the performance improvement of the proposed method compared to the existing method.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.133-137
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• 2016

Millimeter wave wireless communication systems, especially those targeting indoor high rate data transfer, have a strong requirement for high quality wireless link. Unfortunately, in this frequency band, the electromagnetic wave has to sustain the high propagation loss caused by the smaller wavelengths. In this scenario, beamforming technique, which enhances the link quality by focusing the radiation power on a direction, becomes one of the most important techniques in millimeter wave band wireless communication. In recent year, there been conducted many research on beamforming to improve the performance of wireless system. In this paper, we evaluate the performance of a simplified codebook-based beamforming scheme which is based on multiple-procedure and three-state beam selection. The simplified scheme significantly reduces beamforming setup time, comparing to the exhaustive searching, two-level searching adopted in IEEE 802.15.3c standard, and also conventional multi-level scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.500-508
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• 2008

For efficient compatible system between medical clinics, the medical information has to be built on a standardized protocol such as a HL7 for text data and a DICOM for image data. But it is difficult to exchange information between medical clinics because the systems and softwares are different and also a structure of data and a type of code. Therefore we analyze a structure of DICOM file and design an integrated database for effective information sharing and exchange. The WISD system suggested in this paper separate the DICOM file transmitted by medical clinics to text data and image data and store it in the integrated DB(database) by standardized protocol respectively. It is very efficient that each medical clinic can search and exchange information by web browser using the suggested system. The WISD system can not only search and control of image data and patient information through integrated database and internet, but share medical information without extra charge like construction of new system.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.69-78
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• 2021

In this paper, we propose a implementation plan of the human resource pool recruitment system using private (permitted) blockchain. The term Human Resource has become commonly used and has come to recognize human resources as resources. Despite these changes, the use of human resource pools has been sluggish. Once entered, information is often not updated on a regular basis and does not provide sharing, searching, carrier management and anti-counterfeiting. In this research, in order to provide a human resource pool recruitment system that utilizes private (permitted) blockchain, we first used the blockchain network to enable sharing and searching of human resource pools, and to use keywords. Used to get results that meet certain conditions. Second, we added an institutional verification process to ensure the integrity of the input data and prepared preventive measures in the non-technical part by utilizing the structural characteristics of the blockchain to prevent counterfeiting and alteration. Third, we designed and implemented a Dapp (Decentralized application) that includes a Web UI so that each of the three groups can control the blockchain and the predefined processes and business logic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.107-114
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• 2020

Technologies related scan-to-BIM for BIM-based reverse engineering techniques are beginning to be actively introduced in the A.E.C. industry, and the scalability of the technology is growing considerably. This study uses patent analysis based on objective data to find the right direction for Korean Scan-to-BIM technology by identifying the trends in Korea, the United States, Europe, and Japan. This was done using the WIPSON patent search system to find previous research on patent analysis related to building technology, theoretical consideration of scan-to-BIM technology, and published patents. We collected information, verified the process, and extracted valid patents. We used the effective patent data to analyze the annual trend of patent applications, national trends, and technological trends through the International Patent Classification (IPC) code, the types of the top 20 major applicants, and family patent trends.

• Convergence Security Journal
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• v.23 no.3
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• pp.29-36
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• 2023

With the recent surge in exposure to fake advertising phishing sites in search engines, the damage caused by poor search quality and personal information leakage is increasing. In particular, the seriousness of the problem is worsening faster as the possibility of automating the creation of advertising phishing sites through tools such as ChatGPT increases. In this paper, the source code of fake advertising phishing sites was statically analyzed to derive structural commonalities, and among them, a detection crawler that filters sites step by step based on foreign domains and redirection was developed to confirm that fake advertising posts were finally detected. In addition, we demonstrate the need for new guide lines by verifying that the redirection page of fake advertising sites is divided into three types and returns different sites according to each situation. Furthermore, we propose new detection guidelines for fake advertising phishing sites that cannot be detected by existing detection methods.

• Journal of Korea Multimedia Society
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• v.1 no.2
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• pp.239-248
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• 1998

Software reengineering is making various research for solutions against problem of maintain existing system. Reengineering has a meaning of development of softwares on existing systems through the reverse-engineering and the forward-engineering. It extracts classes from existing system's softwares to increase the comprehension of the system and enhance the maintenability of softwares. Most of the important concepts used in reengineering is composition that is restructuring of the existing objects from other components. The classes and clusters in storage have structural relationship with system's main components to reuse in the higher level. These are referenced as dynamic informations through structuring an architect for each of them. The classes are created by extractor, searcher and composer through representing existing object-oriented source code. Each of classes and clusters extract refined informations through optimization. New architecture is created from the cluster based on its classes' relationship in storage. This information can be used as an executable code later on. In this paper, we propose the tools, it presented by this thesis presents a new information to users through analysing, based on reengineering, Object-Oriented informations and practicing composition methodology. These composite classes will increase reusability and produce higher comprehension information to consist maintainability for existing codes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.562-569
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• 2019

Raman spectroscopy has been receiving increased attention as a standoff explosive detection technique. In addition, there is a growing need for a fast search method that can identify raman spectrum for measured chemical substances compared to known raman spectra in large database. By far the most simple and widely used method is to calculate and compare the Euclidean distance between the given spectrum and the spectra in a database. But it is non-trivial problem because of the inherent high dimensionality of the data. One of the most serious problems is the high computational complexity of searching for the closet spectra. To overcome this problem, we presented the MPS Sort with Sorted Variance+PDS method for the fast algorithm to search for the closet spectra in the last paper. the proposed algorithm uses two significant features of a vector, mean values and variance, to reject many unlikely spectra and save a great deal of computation time. In this paper, we present two new methods for the fast algorithm to search for the closet spectra. the PCA+PDS algorithm reduces the amount of computation by reducing the dimension of the data through PCA transformation with the same result as the distance calculation using the whole data. the Hierarchical Cluster Tree algorithm makes a binary hierarchical tree using PCA transformed spectra data. then it start searching from the clusters closest to the input spectrum and do not calculate many spectra that can not be candidates, which save a great deal of computation time. As the Experiment results, PCA+PDS shows about 60.06% performance improvement for the MPS Sort with Sorted Variance+PDS. also, Hierarchical Tree shows about 17.74% performance improvement for the PCA+PDS. The results obtained confirm the effectiveness of the proposed algorithm.

• The Journal of the Acoustical Society of Korea
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• v.14 no.1E
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• pp.46-55
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• 1995

In this paper, we present a new wavelet transform-based CELP coder, called band selection wavelet transform CELP (BS-WTCELP) operated at 4.8 kbps. The proposed algorithm uses a band selection scheme of frequency bands of wavelet transform and selective vector quantization (VQ). The band selection and selective VQ structure is implemented by using a classified VQ structure. The proposed algorithm has about 0.5-1.0 dB improvement in segmental SNR compared with the conventional CELP that uses the random codebook search, while is has significantly reduced computational and storage complexity. Many experimental results have shown that the proposed algorithm is more suitable for most real-applications than the conventional CELP and wavelet transform CELP.

• Journal of Internet Computing and Services
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• v.4 no.2
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• pp.21-30
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• 2003

This paper is to describe how to refer to software objects and reuse them through the web browser so that ail the members of the software development team can collaborate with each other on the development procedure, In addition, we describe how to convert the $ ^*$,mdl design information generated from the UML editor into their corresponding XML data, which is arranged to be saved in the relational database system. Furthermore, we provide a facet retrieval system based on which makes use of a object-oriented thesaurus, which supports an integrated environment through which all the project team members can share a lot of source codes and execution files as weil as object files produced from the web-based collaborative development environment. Finally, we have designed and implemented a web version management system that facilitates software developers to manage in their web-based search for the relationship of design informations.