• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.3
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• pp.95-100
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• 2011

Due to rapid growth and development of telecommunication information technology, interest has been amplified regarding ubiquitous network computing and user-oriented service. Also, the rapid development of related technologies has been a big spotlight. Smart phone, with features such as a PC with advanced features is a mobile phone. According to environment and infrastructure development, a variety of mobile-based application software to provide various kinds of information and services has been released. However, most of them are provider-driven information systems and aim to provide large amounts of information simply to an unspecified number of users. Therefore, customized or personalized provision of information and service explained earlier for individual users has been hardly come true. According to background and need, this study wants to design and implement recommendations system for personalization and customization in mobile environments. To acquire more accurate recommendation results, recommendation system shall be composed using the Hybrid Filtering. Effective information recommendation according to user's situation by using user's context-information of purpose and location that are available in mobile devices before running the filtering of the information to improve the quality of recommendations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.64-75
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• 2007

Service discovery protocols is software components to find specific services or resources on network. The SLP defined by IETF protocol is a framework for automatic service discovery on IP based networks. Automatic service discovery is an important component on ubiquitous computing environment. This paper proposes a service discovery architecture named as SLPA(Service Location Protocol based on AMAAM). AMAAM(Mobility Agent Advertisement Mechanism) is an aggregation-based Mobile IP implementation in MANET. In SLPA, the role of the directory agent is assigned to the mobility agent in AMAAM. The mobility agent periodically beacons an advertisement message which contains both the advertisement of the directory agent in SLP and the advertisement of the mobility agent in Mobile IP. For evaluating the functional correctness of SLPA and the overhead of maintaining a service directory of SLPA. We simulate SLPA using ns-2 and analyze the overhead of control overheads for the aggregation. Through the simulation experiments we show the functional correctness of the proposed architecture and analyze the performance results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.55-63
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• 2007

Multicast is an efficient transport mechanism for community communications and MANET is recently regarded as a promising solution for support ubiquitous computing as an underlying network technology. However, it is hard to deploy multicast mechanism into MANET owing to scarce resources in wireless networks and unpredictable changes in network topology. Several multicast mechanisms have been proposed in the literature to overcome the limitations. Especially, overlay multicasting schemes present several advantages over network based multicasting schemes. Yet, the overlay multicasting schemes still introduce redundant data transmissions that waste network bandwidth and battery of relay nodes. As a result the performance of the network is degraded. To reduce the redundancy, we propose an efficient way to construct an overlay structure as a multicast data delivery tree that utilizes a branch node which belongs to the tree. By using network simulation, we show that the proposed scheme presents higher packet delivery ratio and lower transmission cost than previously proposed schemes.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.585-593
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• 2010

Recently, we designed an interactive virtual space for the multi-purpose hall in Songdo Future City, located in Incheon, Korea. The goal of the design is to make a virtual space that is flexible and can be adjusted thanks to its unfixed seats in order to accommodate different and unspecified audience sizes. Virtual images are interactively adjusted according to the distance, position and size of audiences, information about which is detected by 9 photo sensors. To increase the sense of immersion, intensity and reality, we utilized the technology of scent display that can create appropriate scents to match the images on the screen. The intensity and persistence of scents were determined by the size, distance and position of audiences. The virtual image contains background images and reactive images. The background images repeatedly project images of spring, summer, autumn and winter. The reactive images consist of small portraits or pictures or icons that define or characterize the season types, and these are added to the background image according to the distance, position and size of the audiences.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.21-31
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• 2012

Recently, according to the development of ubiquitous computing technology, the efficient management of locations of moving objects is increasing rapidly in various fields. However, MODBMS and DSMS can not support the efficient real-time management of spatio-temporal stream data of moving objects. Therefore, this paper designed and implemented a spatio-temporal DSMS which can support the efficient real-time management of spatio-temporal stream data of moving objects. Especially, to develop the spatio-temporal DSMS, we extended STREAM of Stanford University and used GEOS that supports spatial data types and spatial operators of OGC. Finally, this paper proved the efficiency of the spatio-temporal DSMS by applying it to the real-time monitoring field which requires the real-time management of spatio-temporal stream data of moving objects.

• Informatization Policy
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• v.17 no.2
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• pp.45-67
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• 2010

This study is to reconstruct the user-oriented e-government service based on home network infrastructure using ubiquitous computing technology. Until now, 31 e-government roadmap tasks have been promoted as main projects of e-government. This study explores what should be respective priorities for the suppliers and users of e-government if the services are provided in linkage with home network infrastructure. The result of survey showed us that the efficiency of administration and the improvement of the civil service, including citizens' online participation should be priorities. In order to reinforce home network infrastructure in implementing u-government, the government, at first, has to relax regulation, support businesses to develop related technologies, and construct safe infrastructure for citizens to use e-government services. Second, businesses should develop home network technologies that include various contents and construct home network systems that citizens can use easily. Third, citizens should have interests and participate in the government policies for home network services. Particularly, this study aims to suggest policies that consider positions of both the suppliers and users of e-government so that home network-based e-government can be implemented in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12B
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• pp.831-837
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• 2005

Personal general purpose computer(PC) has been evolved from desktop to portable mobile device such as tablet PC and PDA. Technology innovation on semiconductor have made it possible to package a reasonably Powerful Processor and memory subsystem with advanced input/output devices. At last these subsystems are miniaturized into wearable system. Wearable computer has recently gained attention as the post PC in the ubiquitous environment. Wearable computing becomes more and more feasible and receives growing attention throughout industry and the consumer marketplaces. This paper proposed and developed WPS that has multimedia features and network features as a wearable embedded platform. We explain the form, overall architecture, functions and user applications of this WPS. This paper also discusses the form of next generation computer platform with intuitive user interfaces and well designed applications in the future.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.214-223
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• 2010

Information & Communication Technology(ICT), called ubiquitous computing, changes our environment in many ways. It also acts on educational environment in concert with new pedagogy. Korean Government gives an efforts to set up the u-School as the educational environment supported by ICT. This study aims to find efficient uses of ICT to cope with the changing education environment and emerging needs of users. The survey research follows the pilot study on the model of future school. The students and teachers in six schools located in Busan answered the questionnaire and 752 individuals were analyzed by the statistical method including frequencies, crosstabs, ANOVA, and factor analysis. The conclusions are as follows: (1) Highly demanded were the u-School facilities to provide pleasant environment as the teachers and students have to spend most of time in classroom, or school premises. In addition, the infrastructures were so desperately required that students are able to control their textbooks and belongings, and efficiently utilize a variety of data. (2) The classroom volume should be planned a bit smaller than the current number of students so that teachers are relieved from the burden of too many student. The needs of students to interact with more students can be bolstered by utilization of ICT. (3) The respondents feel the high needs of computer for student, electronic blackboard, electronic lecture desk, microphone and computer for teacher as the teaching and learning facilities. This showed high needs for teaching and learning facilities enabling the active and individual learning through the use of ICT at education environment. In conclusion, the study proposes the fundamental data to combine u-School elements proper to the current learning and school environment, from the analysis on the use of school facilities, with the subjects, the users of education environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.190-197
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• 2010

The ACR (Access Control Router) of WiBro processes location registration of the Correspondent Node and Home Agent as the Correspondent Node moves between ACRs. Therefore, the location update cost is low compared with MIPv6. However, all packets which are sent and received are sent through the ACR, so as the number of mobile nodes that are managed by the ACR increases, the cost of packet delivery also increases. Therefore, the communication state of the ACR domain remains smooth when the ACR which manages the mobile node in the ACR domain has good performance. However, network delays occur unless the ACR performs well, so the role of the ACR is important. In this paper, we analysis performance of the ACR for efficient realization of the WiBro standard. By using the Deny Probability and the Total Profit of ACR performance and apply it to the Random Walk Mobility model as the mobility model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.581-591
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• 2016

RFID(Radio Frequency IDentification) is a key technology in ubiquitous computing and is expected to be employed in more fields in the near future. Nevertheless, the RFID system is vulnerable to attacks by eavesdropping or altering of the messages transmitted in wireless channels. In 2013, Oh et al. proposed a mutual authentication protocol between a tag and a reader in RFID systems. Their protocol is designed to resist location tracking for privacy protection. However, all tags and readers use only one network-wide key in their protocol and tags are usually vulnerable to physical attacks. We found that their protocol is still vulnerable to tag/reader impersonation attacks and location tracking if an attacker obtains the network-wide key from a tag. In this paper, we propose a security improved authentication protocol for privacy protection in RFID systems. In addition, we demonstrate that the proposed scheme is efficient in terms of computation and communication costs.