• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.3
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• pp.27-45
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• 2010

It is strongly believed that multicast will become one of the most promising services on internet for the next generation. Multicast service can be deployed either on network-layer or application-layer. IP multicast (network-layer multicast) is implemented by network nodes (i.e., routers) and avoids multiple copies of the same datagram on the same link. Despite the conceptual simplicity of IP multicast and its obvious benefits, it has not been widely deployed since there remain many unresolved issues. As an alternative to IP multicast, overlay multicast (application-layer multicast) implements the multicast functionality at end hosts rather than routers. This may require more overall bandwidth than IP multicast because duplicate packets travel the same physical links multiple times, but it provides an inexpensive, deployable method of providing point-to-multipoint group communication. In this paper we develop an efficient method applied greedy algorithm for solving two models of overlay multicast routing protocol that is aimed to construct MDST (Minimum Diameter Spanning Tree : minimum cost path from a source node to all its receivers) and MST (Minimum Spanning Tree : minimum total cost spanning all the members). We also simulate and analyze MDST and MST.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.174-188
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• 2004

In the life environment changed with not only the quality and the price of the products but also the material abundance, it is the most crucial factor for the strategy of product sales to investigate consumer's sensibility and preference degree. In this perspective, it is necessary to design and merchandise the products in cope with each consumer's sensibility and needs as well as its functional aspects. In this paper, we propose the Fashion Design Recommender Agent System (FDRAS-pro) for textile design applying collaborative filtering personalization technique as one of the methods of material development centered on consumer's sensibility and preference. For a collaborative filtering system based on textile, Representative-Attribute Neighborhood is adopted to determine the number or neighbors that will be used for preferences estimation. Pearson's Correlation Coefficient is used to calculate similarity weights among users. We build a database founded on the sensibility adjectives to develop textile designs by extracting the representative sensibility adjectives from users' sensibility and preferences about textile designs. FDRAS-pro recommends textile designs to a customer who has a similar propensity about textile. To investigate the sensibility and emotion according to the effect of design factors, fertile designs were analyzed in terms of 9 design factors, such as, motif source, motif-background ratio, motif variation, motif interpretation, motif arrangement, motif articulation, hue contrast, value contrast, chroma contrast. Finally, we plan to conduct empirical applications to verify the adequacy and the validity of our system.

• Journal of the Korean association of regional geographers
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• v.22 no.1
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• pp.251-266
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• 2016

Intelligent interpolation methods such as dasymetric mapping are considered to be the best way to disaggregate zone-based population data by observing and utilizing the internal variation within each source zone. This research reviews the advantages and problems of the dasymetric mapping method, and presents a geographically weighted regression (GWR) based method to take into consideration the spatial heterogeneity of population density - land cover relationship. The locally adaptive intelligent interpolation method is able to make use of readily available ancillary information in the public domain without the need for additional data processing. In the case study, we use the preclassified National Land Cover Dataset 2011 to test the performance of the proposed method (i.e. the GWR-based multi-class dasymetric method) compared to four other popular population estimation methods (i.e. areal weighting interpolation, pycnophylactic interpolation, binary dasymetric method, and globally fitted ordinary least squares (OLS) based multi-class dasymetric method). The GWR-based multi-class dasymetric method outperforms all other methods. It is attributed to the fact that spatial heterogeneity is accounted for in the process of determining density parameters for land cover classes.

• Journal of the Korea Society for Simulation
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• v.22 no.1
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• pp.9-20
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• 2013

Defense M&S for weapons effectiveness is a realistic way to support virtual warfare similar to real warfare. As the war paradigm becomes platform-centric to network-centric, people try to utilize smartphones as the source of sensor, and command/control data in the simulation-based weapons effectiveness analysis. However, there have been limited researches on integrating smartphones into the weapon simulators, partly due to high modeling cost - modeling cost to accomodate client-server architecture, and re-engineering cost to adapt the simulator on various devices and platforms -, lack of efficient mechanisms to exchange large amount of simulation data, and low-level of security. In this paper, we design and implement Smartphone Adaptor to utilize smartphones for the simulationbased weapons effectiveness analysis. Smartphone Adaptor automatically sends sensor information, GPS and motion data of a client's smartphone to a simulator and receives simulation results from the simulator on the server. Also, we make it possible for data to be transferred safely and quickly through JSON and SEED. Smartphone Adaptor is applied to OpenSIM (Open simulation engine for Interoperable Models) which is an integrated simulation environment for weapons effectiveness analysis, under development of our research team. In this paper, we will show Smartphone Adaptor can be used effectively in constructing a Live simulation, with an example of a chemical simulator.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.97-101
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• 2011

Interplanetary space between Sun and Earth is area of flowing very fast solar wind which is contained X ray, flare, corona mass, etc. occurred Sun surface to Earth. This solar wind is affected directly to Earth magnetosphere and ionosphere so that this bring out broadcasting and communication interruptions, satellite operation obstacles and power gird defects and etc..Solar wind flow in interplanetary space is measured as solar wind speed, density and direction by measuring scintillation value to be produced during radio source is passed through solar wind. The wider effective collective areas and the more radio sources, accuracy of solar wind measuring is got higher. Function test was performed using 3 tiles which was manufactured as prototype. Restriction of quantity of tiles, test was performed to confirm whether measured beam pattern is complied with requirement or not. In this paper, it is shown design and their specification of ground interplanetary radio measurement system as well as technical issues and resolutions which were raised during design phase. Also result of function verification test using prototype is suggested. It is confirmed that measured beam pattern was met with requirement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3462-3468
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• 2015

Regarding countless network disorders or invasions happening nowadays from 2014 until 2015, illegal access intended to attack through the communication line provided by ISP (Internet Service Provider) appears to be the source of the problem. As a defensive way to prevent such network-based attacks, not only stabilization structures for network communication but various policies as well as physical security devices and solutions corresponding to those have been realized and established. Therefore, now is the time to gain foundational research data to secure network security sections by producing logical area on communication bandwidth or such, suggest tasks to expand the communication line which is another research topic in the network security market, and recognize the fact that the active communication bandwidth linkage paradigm using network communication bandwidth is needed as one of the areas that can realize physical security. Additionally, it is necessary to limit the data in the forms of organizing visible security structures into a certain range of physical information by re-dividing communication capacity being currently provided by telecommunicators into subdivided organizational areas and applying the logical virtualization of communication capacity in each of the areas divided. By proposing a network security section based on a logical field application in place of the existing physical structure, basic data that designs a stable physical network communication structure will be provided.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.7
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• pp.319-326
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• 2016

Given the attributes of mobile apps that shorten the time to make purchase decisions while enabling easy purchase cancellations, usability can be regarded to be a highly prioritized quality attribute among the diverse quality attributes that must be provided by mobile apps. With that backdrop, mobile app developers have been making great effort to minimize usability hampering elements that degrade the merchantability of apps in many ways. Most elements that hamper the convenience in use of mobile apps stem from those potential errors that occur when GUIs are designed. In our previous study, we have proposed a technique to analyze the usability of mobile apps using user behavior logs. We proposes a technique to detect usability hampering elements lying dormant in mobile apps' GUI models by expressing user behavior logs with finite state models, combining user behavior models extracted from multiple users, and comparing the combined user behavior model with the expected behavior model on which the designer's intention is reflected. In addition, to reduce the burden of the repeated test operations that have been conducted by existing developers to detect usability errors, the present paper also proposes a mobile usability error detection automation tool that enables automatic application of the proposed technique. The utility of the proposed technique and tool is being discussed through comparison between the GUI issue reports presented by actual open source app developers and the symptoms detected by the proposed technique.

• Journal of Gifted/Talented Education
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• v.20 no.3
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• pp.901-919
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• 2010

We have examined the perception and the knowledge of science-gifted students and general students in middle school level about high technology related to the science. The subjects of the investigation were 113 gifted students belonging to the universities' science-gifted education center in Busan or Ulsan, and 159 general students belonging to 2 middle schools in Busan. The survey was conducted with questionnaires on the perceptions concerning the high technology related to the science and the knowledge of a cellular phone without an antenna, and an LED(Light Emission Diode). The results of this survey concluded that the gifted students were more interested and aware of the high technology than the general students, these results are statistically significant. It has been found that there are significant differences between the gifted students and the general students in terms of the areas they want to learn, the source of information and the preferred learning method in advanced science and technology. Also, the gifted students were recognized to be better than general students in understanding an electromagnetic wave related to a cellular phone without an antenna, and a semiconductor connection with an LED.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.1
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• pp.1-18
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• 2023

Similar software is often developed with the Clone-And-Own (CAO) approach that copies and modifies existing artifacts. The CAO approach is considered as a bad practice because it makes maintenance difficult as the number of cloned products increases. Software product line engineering is a methodology that can solve the issue of the CAO approach by developing a product family through systematic reuse. Migrating product families that have been developed with the CAO approach to the product line engineering begins with finding, integrating, and building them as reusable assets. However, cloning occurs at various levels from directories to code lines, and their structures can be changed. This makes it difficult to build product line code base simply by finding clones. Successful migration thus requires unifying the source code's file path, class name, and method signature. This paper proposes a clustering method that identifies a set of similar codes scattered across product variants and some of their method full paths are different, so path unification is necessary. In order to show the effectiveness of the proposed method, we conducted an experiment using the Apo Games product line, which has evolved with the CAO approach. As a result, the average precision of clustering performed without preprocessing was 0.91 and the number of identified common clusters was 0, whereas our method showed 0.98 and 15 respectively.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.610-620
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• 2022

An acoustic vector sensor can simultaneously receive vector quantities, such as particle velocity and acceleration, as well as acoustic pressure at one location, and thus it can be used as a single input multiple output receiver in underwater acoustic communication systems. On the other hand, vector signals received by a single vector sensor have different channel characteristics due to the azimuth angle between the source and receiver and the difference in propagation angle of multipath in each component, producing different communication performances. In this paper, we propose a channel parameter-based weighting method to improve the performance of an acoustic communication system using a single vector sensor. To verify the proposed method, we used communication data collected from the experiment conducted during the KOREX-17 (Korea Reverberation Experiment). For communication demodulation, block-based time reversal technique which is robust against time-varying channels were utilized. Finally, the communication results showed that the effectiveness of the channel parameter-based weighting method for the underwater communication system using a single vector sensor was verified.