• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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• pp.202-210
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• 1995

Given a tree T with a root node 0 having the capacity H and a profit $c_{v}$ and a demand $d_{v}$ on each node v of T, the capacitated subtree of a tree problem(CSTP) is to find a subtree of T containing the root that has the maximum total profit, the sum of profits over the subtree, and also satisfies the constraint of which the sum of demands over the subtree must be less than or equal to H. We first define the so-called critical item for CSTP and find an upper bound on the linear programming relaxation of CSTP. We then present our branch and bound algorithm for solving CSTP and finally report the computational results on a set of randomly generated test problems.s.s.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.307-316
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• 2001

Two hard sub-problems have emerged relating to the use of mobile agents for service management tasks. First, what is their impact on security, and second, how can they receive a flexible capacity to adapt to an open range of different environments on demand, without introducing trio stringent prior assumptions. In this paper, we present work towards solving the second problem, which is of particular interest to management software, because it typically needs to excert fine-grained and therefore particular resource control. We suggest a mechanism that reassembles mobile agents from smaller sub-components during arrival at each hop. The process incorporates patterns of unmutable and mutable sub-components, and is informed by the conditions of each local environment. We discuss different kinds of software adaptation and draw a distinction between static and continuous forms. Our software prototype for dynamic adaptation provides a concept far exchanging environment-dependent implementations of mobile agents during runtime. Dynamic adaptation enhances efficiency of mobile code in terms of bandwidth usage and scalability.

• Journal of KIBIM
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• v.7 no.2
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• pp.1-7
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• 2017

Urban planning involves many different disciplines. In order for the related stakeholders to have better understanding and acceptable outcomes, planners are required to present a methodology that would properly reflect people's interest. In order to justify the demand and distribute people's interest, planners actively utilized the suitability analysis. Accordingly, a suitability analysis to find the optimal route for high-speed rail was performed in this paper. With ArcGIS and geographic data sets, simple map algebra could be used. The final product of this research was a map indicating the suitable routes for high-speed rail using the shortest path analysis.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.247-248
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• 2008

A recent dynamic increase in demand for wireless multimedia services has greatly accelerated the research on dynamic channel adaptation of high quality video applications. In this paper, we explore a theoretical approach to cross-layer optimization between multimedia and wireless networks by means of a quality criterion termed "visual throughput" for downlink video transmission using a layered coding algorithm. We obtain the optimal loading ratio of orthogonal frequency division multiple access (OFDMA) subcarriers through an optimization problem balancing the trade-off relationship between inter-cell interference (ICI) and channel throughput. In the simulation, we show that the visual throughput gain at the cell boundary is increased by about 32%.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.145-146
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• 2006

Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe most complicated nano- and bio-fluidic phenomena. In this presentation, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body will be introduced as a blue ocean strategy.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.14-17
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• 2008

Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.14-17
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• 2008

Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.196-203
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• 2022

Developing smart cities increasingly relies on metaverse technology. This has become much more apparent in the post-COVID-19 pandemic urban environment. The demand for fast processing of huge amounts of data and the convergence of various media types is essential for keeping city residents well-informed and safe. This paper builds on recent research on metaverse, smart cities, and digital outdoor advertising media. It proposes that "space culture media", which collectively functions by using physical or virtual spatial information, will play a key role in the smart city, functioning as an augmented city. Specifically, this paper deals with significant issues related to the smart city changes created by tecoration, a metaverse urban media space facilitated and enhanced through digital outdoor advertising.

• Electronics and Telecommunications Trends
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• v.37 no.3
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• pp.33-40
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• 2022

Communication technologies are evolving to meet the ever-increasing demand for fast transmission speeds and large capacity. However, the introduction of new mobile networks, such as 5G, should be accompanied by changes in corresponding frequency and modulation techniques to enable the commercialization of its services. Hence, investigating the human health effects of electromagnetic exposures used in these new communication systems is crucial. Since in vitro electromagnetic experiments can provide essential information on important mechanisms of exposure effects, this article presents in vitro exposure systems necessary for reliable experiments. Moreover, the fundamental requirements for system implementation and the features of various systems are discussed.

• Electronics and Telecommunications Trends
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• v.39 no.3
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• pp.69-78
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• 2024

Cloud computing technology based on centralized high-performance computing has brought about major changes across the information technology industry and led to new paradigms. However, with the rapid development of the industry and increasing need for mass generation and real-time processing of data across various fields, centralized cloud computing is lagging behind the demand. This is particularly critical in emerging technologies such as autonomous driving, the metaverse, and augmented/virtual reality that require the provision of services with ultralow latency for real-time performance. To address existing limitations, distributed and edge cloud computing technologies have recently gained attention. These technologies allow for data to be processed and analyzed closer to their point of generation, substantially reducing the response times and optimizing the network bandwidth usage. We describe distributed and edge cloud computing technologies and explore the latest trends in their standardization.