• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.481-488
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• 2005

The Mobile W provides an efficient and scalable mechanism for host mobility within the Internet. However, the mobility implies higher security risks than static operations in fixed networks. In this paper, the Mobile IP has been adapted to allow AAA protocol that supports authentication, authorization, and accounting(AAA) for security and collection for accounting information of network usage by mobile nodes(MNs). For this goal, we Propose the boundary tone overlapped network structure while solidifying the security for the authentication of an MN. That is, the Proposed scheme delivers the session keys at the wired link for MN's security instead of the wireless one, so that it provides a fast and seamless handoff mechanism. According to the analysis of modeling result, the proposed mechanism compared to the existing session key reuse method is up to about $40\%$ better in terms of normalized surcharge for the handoff failure rate that considers handoff total time.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.883-892
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• 2002

Mobile IP has been designed only to maintain communications as they move from place to place, so it doesn't guarantee Quality of Service (QoS). QoS in mobile IP is important to provide multimedia and real-time applications services in mobile environment, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to guarantee QoS as a main issue in mobile IP research area. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-based routing. After modeling of suggested method and existing handoff method, simulations are carried out with NS -2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.82-84
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• 2004

Java's performance is sometimes not acceptable due to interpretation overhead by the Java Virtual Machine (JVM). In this paper, we present a compiler structure of Java-to-C translator for high performance on resource limited environment like mobile devices. Our compiler framework translates Java into C codes to preserve Java's programming semantics such as inheritance, method overloading, virtual method invocation, and so on. Also our compiler fully supports Connected Limited Device Configuration (CLDC) 1.0 API's. We show that our compiler improves the speedup by up to eleven times more than JVM-only execution in measured benchmarks.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.95-104
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• 2004

This paper propose a motion estimator architecture to reduce the power consumption of the most-power-consuming motion estimation method when designing multimedia SoC with deep submicron technologies below 0.13${\mu}{\textrm}{m}$. The proposed architecture considers both dynamic and static power consumption so that it is suitable for large leakage process technologies, while conventional architectures consider only dynamic power consumption. Consequently, it is suitable for mobile information terminals such as mobile videophone where efficient power management is essential. It exploits full search method for simple hardware implementation. It also exploits early break-off method to reduce dynamic power consumption. To reduce static power consumption, megablock shutdown method considering power line noise is also employed. To evaluate the proposed architecture when applied multimedia SoC, system-level control flow and low-power control algorithm are developed and the power consumption was calculated based on thor From the simulation results, power consumption was reduced to about 60%. Considering the line width reduction and increased leakage current due to heat dissipation in chip core, the proposed architecture shows steady power reduction while it goes worse in conventional architectures.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.345-347
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• 2008

실제 휴대폰 환경에서 쓰이고 있는 전력 시스템이 어떻게 되어 있는지 고찰해보고, 어떤 것들이 문제가 되고 있으며, 그 해결방안으로는 어떤 것들이 있는지 알아본다. 각 regulator의 정의와 그 spec에 대하여 장단점 분석과 함께 실무적으로 어떻게 응용되고 있으며 미래의 발전방향은 어떻게 될 것인지 고찰한다. SoC(System on Chip)의 결정체인 휴대폰에서 전력 시스템 디자인이 차지하는 그 영향에 대해 논하고 그 application 관점에서 체크리스트를 만들어보기로 한다.

• Journal of Information Technology Applications and Management
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• v.20 no.1
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• pp.67-85
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• 2013

The emergence of RFID markets and development of various RFID-embedded mobile devices has brought fundamental changes to our lives. As the availability of RFID readers and tags that are implanted in smart phones and table PCs increases, information on RFID-affixed objects can be tracked wirelessly and this had open possibilities for B2B businesses to be run like B2C businesses. However, given the popularity of the RFID markets, there is limited research in this area. This paper serves to develop an extended technology acceptance model by Mobile RFID characteristics (perceived cost, security, instant connectivity, context awareness, and result demonstrability) examines the determinant factors that cause the acceptance of mobile RFID. To do so, the study conducted a survey targeting smart phone users and used the PLS path modeling, one of the structural equation models to verify the significance of research hypothesis. As a result, perceived cost, instant connectivity, context awareness, and result demonstrability turned out to have a real effect on intention to use mobile RFID by means of perceived usefulness and perceived ease of use. Security turned out to have a partial effect on intention to use mobile RFID by means of perceived usefulness or perceived ease of Use.

• Journal of Korea Game Society
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• v.6 no.1
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• pp.21-28
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• 2006

This study focused on design and implementation of Mobile 3D Bluetooth Engine based on OpenGL-ES. In Mobile 3D network game so far, there is a form the mainstream of wireless internet game using WAP and VM. But, VM game are popular because of an excessive communication expense problem for this mobile network game that occur when connect to wireless internet as point out to problem by it, that is, stand-alone game are very popular. This study introduce a mobile 3D Bluetooth Engine which is based on mobile 3D standard using OpenGL-ES to solve a mobile network game generally that occurs when connect to take pleasure a wireless internet from some people into a short distance.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.139-146
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• 2007

Mobile Sensor Network(MSN) is actively studied due to the advent of mobile sensors such as Robomote and Robotic Sensor Agents(RSAs), However, existing studies on MSN have mainly focused on coverage hole problem which occurs in Stationary Sensor Network(SSN). To address coverage hole problem, these studies make mobile sensors move temporarily so that they do not make the best use of the mobility of mobile sensors, Thus, a mechanism utilizing the continuous movement of mobile sensors is proposed to improve the network coverage performance. However, this mechanism is presently immature and does not explain how to make routing path and send data from mobile sensors to a sink node, Therefore, to efficiently make routing path and send data from mobile sensors to a sink node, we propose a communication protocol for mobile sensor network where mobile sensors continuously move. The proposed protocol deploys not only mobile sensors but also stationary sensors which send sensing data to a sink node instead of mobile sensors. Simulation results show that the proposed protocol improves the performance in terms of network coverage and traffic overhead, compared to conventional SSN protocols.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.733-742
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• 2002

It has been known that the host mobility feature has very significant impact on the QoS (Quality of Service), which is usually required to a real-time multimedia application. The existing QoS support mechanisms to provide the real-time services to fixed network environment, like as RSVP, are inadequate to accommodate the mobile hosts which can frequently change their point of attachments to the fixed network. So, MRSVP (Mobile RSVP) protocol has been proposed to reduce the impacts of host mobility on QoS guarantees, in which a mobile host needs to make advance resource reservations at multiple locations it may possibly visit during the lifetime of the connection. This paper proposes a dynamic dual anchor node (DDAN) architecture which integrates the MRSVP and RSVP tunnel, in addition to the Mobile IP Regional Registration protocol. By limiting the resource reserved in local area, it preserves the lower level of resource reservation, but provides approximately the same degree of QoS support as the existing MRSVP.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.2
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• pp.89-101
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• 2005

Research on highly abstracted system modeling and simulation has received a great deal of attention as of the concept of platform based design is becoming ubiquitous. From a practical design point of view, such modeling and simulation must consider the following: (i) fast simulation speed and cycle accuracy, (ii) early availability for early stage software development, (iii) inter-operability with external tools for software development, and (iv) reusability of the models. Unfortunately, however, all of the previous works only partially addresses the requirements, due to the inherent conflicts among the requirements. The objective of this study is to develop a new system design methodology to effectively address the requirements mentioned above. We propose a new transaction-level system modeling methodology, called ViP (Virtual Platform). We propose a two-step approach in the ViP method. In phase 1, we create a ViP for early stage software development (before RTL freeze). The ViP created in this step provides high speed simulation, lower cycle accuracy with only minor modeling effort.(satisfying (ii)). In phase 2, we refine the ViP to increase the cycle accuracy for system performance analysis and software optimization (satisfying (i)). We also propose a systematic ViP modeling flow and unified interface scheme based on utilities developed for maximizing reusability and productivity (satisfying (ii) and (iv)) and finally, we demonstrate VChannel, a generic scheme to provide a connection between the ViP and the host-resident application software (satisfying (iii)). ViP had been applied to several System-on-a-chip (SoC) designs including mobile applications, enabling engineers to improve performance while reducing the software development time by 30% compared to traditional methods.