• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.544-550
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• 2006

Next-generation wireless/mobile networks are envisioned to have an IP-based infrastructure. One of the research challenges for next-generation all IP-based networks is the design of intelligent mobility management technologies that have a seamless mobility and minimal signaling overhead. Recently, HMIPv6 was proposed by the IETF for efficient mobility management. HMIPv6 reduces the amount of signaling and improves the performance of MIPv6 in terms of handover latency. However the MAP can be a single point of performance bottleneck when there are a lot of local movements. HMIPv6 can cause signaling overhead due to the unnecessary location update of idle mobile nodes. Therefore, in this paper, we propose the dynamic paging Mobile IPv6 that reduces the signaling cost of the unnecessary location updates using IP paging and organizes dynamically optimal MAP area according to user's mobility and traffic. We show performance results that are obtained from the average total location update cost and packet delivery cost.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.81-88
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• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, Live video streaming, Live video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Those services are usually provided by using the centralized communication server. However, since all multimedia traffic is exchanged through a communication server, it often has the scalability problem with regard to traffic management. Our main purpose is for group smart users to provide scalable live multimedia streaming service based on P2P network. To do this, we have designed an architecture of P2P-based service management for mobile group communication management and service management protocol. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwid th utilization.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.64-72
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• 1997

Since the average speed calculated with encoder pulses inevitably has time delay, the control performance as well as the system stability is deteriorated. especially at the low speed region. Additionally, the distorted inverter output voltage due to the dead time effects and the forward voltage drops of the VSI (Voltage Source Inverter) causes torque ripples and their effects are more severe at the low speed operation of an induction motor. In this paper, an accurate speed estimation method using Kalman Filter Algorithm is presented to improve the performance of an induction motor speed control with a low precision encoder at low speed legion. The dead time effects and the forward voltage drops of the VSI are feedforwardly compensated to produce an exact inverter output voltage.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.87-94
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• 2001

A survey was undertaken among a group of dentists working at private dental clinics to investigate the state of dental care and the level of education and training in the dental care to people with handicaps. Forty four percents of dental clinics take care of one more patients per month. The types of handicaps were physical, mental, sensory handicap and autism. The common problems are difficulty in communication and delay of treatment. Forty nine percents of dentists got education and nineteen percents had clinical experience for dental care of handicapped patients. Most of dentists felt necessity of training program and establishment of specialized dental hospital supported by government for the handicapped. This study indicated the necessity of undergraduate and postgraduate education and clinical training for dental care of handicapped patients.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.69-76
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• 2014

In this paper, we propose a buffering scheme to improve the performance in P2P live streaming systems by adjusting the ratio of caching and prefetching portion of each peer. To this end, we assign all the peers into many groups depending on their playback periods. We then determine the ratio of caching and prefetching portion in each peer depending on its playback time position relative to those of other peers within the same group. In other words, as the playback position of a peer gets later, we increase the ratio of its caching portion. On the contrary, as the playback position of a peer gets eariler, we increase the ratio of its prefetching portion. This can significantly increase the degree of data duplication among peers that belong to each specific group. By simulation experiments, we show that our proposed an integrated prefetching/caching scheme can improve the performance considerably in terms of jitter ratio, initial playback delay and shared buffermap ratio when compared to the existing fixed portion buffering scheme.

• Progress in Medical Physics
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• v.24 no.3
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• pp.183-190
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• 2013

Recently, the photoacoustic imaging system has been widely and intensively developed, and has been shown the possibility of diagnosis for early stage cancer. In this study, we developed a photoacoustic tomography imaging system with a commercial ultra sound device and a linear array probe. A tube phantom and a chicken breast phantom was made for the possibility of a system as a breast cancer detection. A moving average filter and a band pass filter with 3~6 MHz bandwidth were developed for background noise elimination before delay-and-sum beamforming algorithm was used for image reconstruction. As a result, we showed that some signal processing procedure before beamforming was effective for the photoacoustic image reconstruction.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.963-973
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• 2005

Increasing attention is being recently devoted to various problems inherent in the topological design of networks systems. The topological structure of these networks can be based on service centers, terminals (users), and connection cable. Lately, these network systems are well designed with tiber optic cable, because the requirements from users become increased. But considering the high cost of the fiber optic cable, it is more desirable that the network architecture is composed of a spanning tree. In this paper, we present a GA (Genetic Algorithm) for solving bicriteria network topology design problems of wide-band communication networks connected with fiber optic cable, considering the connection cost, average message delay, and the network reliability We also employ the $Pr\ddot{u}fer$ number (PN) and cluster string in order to represent chromosomes. Finally, we get some experiments in order to certify that the proposed GA is the more effective and efficient method in terms of the computation time as well as the Pareto optimality.

• Smart Media Journal
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• v.5 no.4
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• pp.18-25
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• 2016

Virtualized hardware resources provides efficiency in use and easy of management. Based on the benefits, virtualization techniques are used to build large server clusters and cloud systems. The performance of a virtualized system is significantly affected by the virtual machine scheduler. However, the existing virtual machine scheduler have a problem in that the I/O response is reduced in accordance with the scheduling delay becomes longer. In this paper, we introduce the Loan/Redemption mechanism of a virtual machine scheduler in order to improve the responsiveness to I/O events. The proposed scheme gives additional credits for to virtual machines and classifies the task characteristics of each virtual machine by analyzing the credit consumption pattern. When an I/O event arrives, the scheduling priority of a virtual machine is temporally increased based on the analysis. The evaluation based on the implementation shows that the proposed scheme improves the I/O response 60% and bandwidth of virtual machines 62% compared to those of the existing virtual machine scheduler.

• Fire Science and Engineering
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• v.27 no.5
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• pp.64-69
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• 2013

The autoignition temperatures (AITs) of solvent mixture was important index for the safe handling of flammable liquids which constitute the solvent mixtures. This study measured the AITs and ignition delay time for n-propanol and formic acid system by using ASTM E659 apparatus. The AITs of n-Propanol and Formic acid which constituted binary system were $435^{\circ}C$ and $498^{\circ}C$, respectively. The experimental AITs of n-propanol and formic acid system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D. (average absolute deviation). And n- Propanol and formic acid system was shown the minimum autoignition temperature behavior (MAITB).

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.527-531
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• 2003

Hot-water extract from selected medicinal herbs of diabetes prescription was mixed with brown rice and pearled barley flours and extruded to prepare a reconstituted grain for diabetes millitus patients. Even though the cooked reconstituted grain containing medicinal herb extract was somewhat different from cooked ordinary rice in textural properties measured by texture analyzer, it was estimated to be organoleptically acceptable in sensory parameters. The reconstituted grain added with medicinal herb extract reduced the rate of dialysis of glucose evaluated by in vitro dialysis experiment. The effects of reconstituted grain diet on blood glucose levels in diabetes patients were studied during 3-week period. Compared to normal diet, the reconstituted grain diet for 2 weeks significantly decreased the fasting and 2-hr postprandial blood glucose levels in diabetes patients by 14% and 10%, respectively. These results suggested that the reconstituted grain could be used as an effective therapeutic diet for the control of diabetes mellitus.