• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.699-700
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• 2008

In this paper, we implement Mobile AP system, which has Multihoming function providing vertical handover between WiBro and HSDPA networks. We monitor packet drop in networks during binding updates(BU) and acknowledgement(BA) and analyze handover latency. We propose methodology to reduce handover latency and describe the further development direction of Mobile AP system.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.293-294
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• 2008

In ubiquitous environment, using of IPv6 address is essential. In this paper, we study about the network entry procedure based on IEEE 802.16 and discuss the mechanism of IP version negotiation during the procedure for IPv4/IPv6 dual stack service in WiBro.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.43-57
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• 2007

This paper considers the technological competitiveness of aircraft infra industries that are bases of the aircraft industry development in Korea. We performed focus group interviews to aircraft industry specialists and classified the aircraft infra industries by eight fields: metallurgical assembly, general machinery, precision instruments, materials & parts, communication appliances, computer, semi-conductor/ electronic component, electronics. Through the United States patents analysis for the G7 countries and Korea during 1995-2006, we identified the technological specificities and competences of each country. RTA(Revealed Technology Advantage) index and CII(Current Impact Index) are used to examine the technological specificity and technological competence respectively. Finally, we introduced TCI(Technological Competitiveness Index) which could reflect quantitative level as well as qualitative level of patents for each aircraft infra industry. The results show that Korea has occupied the technological competitiveness in the semi-conductor and electronic component industry out of eight aircraft infra industries, and achieved a competitive edge in communication appliance industry in the mid 2000s.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.60-62
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• 2005

In this study, the automatic tracking algorithm tracing a human face is proposed by using YCbCr color coordinated information and its thermal properties expressed in terms of thermal indexes in an infra-red image. The facial candidates are separately estimated in CbCr color and infra-red domain, respectively with applying the morphological image processing operations and the geometrical shape measures for fitting the elliptical features of a human face. The identification of a true face is accomplished by logical 'AND' operation between the refined image in CbCr color and infra-red domain.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.718-723
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• 2009

The purpose of this study is to present an in-site evaluation method for building insulation performance using Infra-red camera. The research contents of this study are to evaluate validity and suitability of building insulation defect survey using Infra-red camera for apartment housing with temperature & heat flow pattern analyze method. By establishing the in-site evaluation method building insulation performance using infra-red camera, it is expected that 1) building envelope repair market will be activated by using developed method in ESCO and remodeling companies, 2) the method developed in this research will contribute to reduce national energy consumption by promoting old building insulation remodeling.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.187-188
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• 2007

A stripline fed slot antenna for UWB communication is designed by using Ensemble simulator. The antenna has a broadband characteristics which causes a fork-like tuning stub. The ground of this antenna has two conductor lines for WLAN band(5GHz band) rejection.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.9
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• pp.577-579
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• 2005

In this study, the automatic tracking algorithm tracing a human face is proposed by using YCbCr color coordinated information and its thermal properties expressed in terms of thermal indexes in an infra-red image. The facial candidates are separately estimated in CbCr color and infra-red domain, respectively with applying the morphological image processing operations and the geometrical shape measures for fitting the elliptical features of a human face. The identification of a true face is accomplished by logical 'AND' operation between the refined image in CbCr color and infra-red domain.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.4
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• pp.151-157
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• 2023

RPL (IPv6 Routing Protocol for Low-power Lossy Network) is a standardized routing protocol for LLNs (Low power and Lossy Networks) by the IETF (Internet Engineering Task Force). RPL creates routes and builds a DODAG (Destination Oriented Directed Acyclic Graph) through OF (Objective Function) defining routing metrics and optimization objectives. RPL supports a leaf mode which does not allow any child nodes. In this paper, we propose INFRA-RPL which provides a dynamic leaf mode functionality to a leaf node with the mobility. The proposed protocol is implemented in the open-source IoT operating system, Contiki-NG and Cooja simulator, and its performance is evaluated. The evaluation results show that INFRA-RPL outperforms the existing protocols in the terms of PDR, latency, and control message overhead.

• Korean Management Science Review
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• v.27 no.3
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• pp.99-115
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• 2010

We classified quality management practices of manufacturing companies into 'Infra' factor and 'Process' factor which were introduced based on existing literatures and previous studies related to quality management. It was our first objective to confirm its conformance in Korean manufacturing industry, and to examine the two factors effect positively on production performance. Moreover, we tried to examine whether JIT and workforce management have an moderate effect on 'Infra and Process factors-performance' relationship, using moderate regression. As the result of empirical study on nationwide manufacturing companies, we had the results that the classification between Infra factor and Process factor in quality management practices was valid in Korean manufacturing companies, and that the two factors gave performances positive effect. Moreover, our secondary analysis showed that JIT had an positive moderate effect on the Infra factor while workforce management on the Process factor. With these results, we have an interpretation that manufacturing companies which aim to enhance short term performances have to concentrate their effort and investment on Process factor and, on the other hand, ones which aims to improve long term performances on Infra factor.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.5
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• pp.67-81
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• 2017

Because of lack of accurate understanding of the mechanism of urban heat island (UHI) phenomenon and lack of scientific discussion, it is hard to come up with effective measures to mitigate UHI phenomenon. This study systematically described the UHI and suggested the solutions using green-infrastructure (green-infra). The factors that control UHI are very diverse: radiant heat flux, latent heat flux, storage heat flux, and artificial heat flux, and the air temperature is formed by the combination effect of radiation, conduction and convection. Green-infra strategies can improve thermal environment by reducing radiant heat flux (the albedo effect, the shade effect), increasing latent heat flux (the evapotranspiration effect), and creating a wind path (cooling air flow). As a result of measurement, green-infra could reduce radiant heat flux as $270W/m^2$ due to shadow effect and produce $170W/m^2$ latent heat flux due to evaporation. Finally, green-infra can be applied differently on the macro(urban) scale and micro scale, therefore, we should plan and design green-infra after the target objects of structures are set.