• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.639-640
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• 2011

P2P VoD 스트리밍에서 비디오를 순차적으로 시청하는 패턴과 더불어 비디오 재생지점의 임의 변경을 허용하는 VCR 기능과 같은 사용자 interactivity 지원 및 재생지점 변경 시 스트리밍 지연을 최소화 하기 위한 연구가 활발하게 진행되어 왔다. 본 논문에서는 VCR 기능 지원을 위해 비디오 전 구간에 대해 피어들이 소유한 오프셋을 오버레이에 확률적으로 등록과 상승을 수행함에 따라 인기도가 누적되며 이를 통해 오프셋을 기반으로 하여 피어들이 논리적으로 오버레이상에 형성 및 유지되게 된다. 이에 따라, 인기지점의 오프셋들은 높은 계층에 유지되므로 피어들은 재생확률이 높은 인기 오프셋을 우선적으로 선반입하여 VCR 동작 요청 시 스트리밍 성능을 향상시키는 계층 상승기법 기반의 오버레이를 제안한다.

• The Korean Journal of Nuclear Medicine
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• v.37 no.3
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• pp.178-189
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• 2003

Purpose: Cellular uptakes of $^{99m}Tc-sestamibi(MIBI)\;and\;\;^{99m}Tc-tetrofosmin$ into cancer cell lines expressing multidrug resistance(MDR) were investigated and compared. The effects of verapamil and cyclosporin A, well-known multidrug resistant reversing agents, on cellular uptakes of both tracers were also compared. Materials and Methods: Doxorubicin-resistant HCT15/CL02 human colorectal cell and doxorubicin-resistant K562(Adr) and vincristine-resistant K562(Vcr) human leukemic cells were studied. RT-PCR analysis was used for the detection of mdr1 mRNA expression. MDR-reversal effects with verapamil and cyclosporine A were evaluated at different drug concentrations after incubation with MIBI and tetrofosmin for 1, 15, 30, 45 and 60 min, using single-cell suspensions at $1{\times}10^6cells/ml$ incubated at $37^{\circ}C$. Radioactivity in supernatants and pellets were measured with gamma well counter. Results: The cellular uptakes of MIBI and tetrofosmin in K562(Adr) and K562(Vcr) were lower than those of parental K562 cell. In HCT15/CL02 cells and K562(Adr) cells, there were no significant difference in cellular uptakes of both tracers, but cellular uptake of MIBI was higher than that of tetrofosmin in K562(Vcr) cells. Coincubation with verapamil resulted in a increase In cellular uptakes of MIBI and tetrofosmin. Verapamil increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 11.9- and 6.8-fold, by K562(Adr) cell by 14.3- and 8-fold and by K562(Vcr) cell by 7- and 5.7-fold in maximum, respectively. Cyciosporin A increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 10- and 2.4-fold, by K562(Adr) cell by 44- and 13-fold and by K562(Vcr) cell by 18.8- and 11.8-fold in maximum, respectively Conclusion: Taking together, MIBI and tetrofosmin are considered as suitable radiopharmaceuticals for defecting multidrug resistance. However, MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators. Since cellular uptakes of both tracers might differ in different cell types, further experiments regarding differences in cellular uptakes between cell types should be explored.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.6
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• pp.119-127
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• 1996

The proposed method uses a signal of the smae frequency as the input modulating carrier frequency and of a different phase. This signal is generated in the digital automatic frequency control part to decide the input color demodulated signal. And the phase error from the burst signal is calculated. The calculated phase error is utilized to rmove the phase error contained inthe demodulated color signal. In this paper, digital signal processing of automatic color control is proposed for VCR system campatible with both NTSC and PAL TV systems.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.136-138
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• 2003

인기있는 비디오 스트림을 서비스하는 VOD시스템에서 다수의 사용자가 하나의 스트림을 공유할 수 있는 방법 중 하나로 주기적 브로드캐스팅 기법이 있다. 이 방법은 비디오 스트림을 주기적으로 브로드캐스팅해줌으로서 다수의 사용자에 대한 서버의 로드가 일정하게 유지되는 효과로 확장성(Scalability)을 갖지만 별도의 채널을 두지 않는 한 VCR 기능을 제공할 수 없고 서비스 응답 시간이 길게 된다. 본 논문에서는 기존의 방법에 On Demand 기능을 만족시키기 위해 프락시 기반 프리픽스 기술을 도입하고 VCR의 일부 기능을 구현할 수 있는 방법을 제안하였다.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.41-51
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• 2005

We examined whether extracts from 14 local citrus spp. on Jeju Island (Korea) contained chemosensitizing activity that would increase the cytotoxic effect of vincristine(VCR) in drug-resistant cancer cells. We report that methanol extracts from fruits and flowers of some species had a chemosensitizing effect that reversed P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). Using drug-sensitive AML-2/WT and drug-resistant AML-2/D100 in the absence of VCR in human acute myelogenous leukemia cells we found that fruit or flower extracts alone generally had low cytotoxicity $(IC_{50}>200\;{\mu}g/ml)$. In studies examining the effect of extracts on 120 ng/ml VCR cytotoxicity in drug-resistant AML-2/D100 cells, we found that immature fruit extracts had greater chemosensitizing activity than either extracts from mature fruit or flower. Of the 14 species examined, the immature fruit extract from Inchangkyool (Citrus ichangiensis) showed the hishest chemosensitizing index(CI) valus. Immature fruit extracts of Hongkyool(C. tachibana), Byungkyool(C. platymamma), Cheongkyool(C. nippokoreana) and Jinkyool (C. sunki) also strongly potentiated VCR cytotoxicity in AML-2/D100 cells. The chemosensitizing effect of peel extracts was 2-10-fold that of whole fruit extracts from Hongkyool (C. tachibana), Byungkyool (C. platymamma) and Inchangkyool (C. inchangiensis). The CI values for flower extracts were higher than those for mature fruit extracts, but lower than those for immature fruit extracts. These results indicate that immature citrus fruits contain compounds that do not exert their activity solely through cytotoxicity. In particular, Incahngkyool (C. inchangiensis), Byungkyool(C.platymamma), Cheongkyool(C. nippokoreana) and Hongkyool (C. tahibana) may be useful sources of chemosensitizing compounds.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.31-36
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• 1994

The bonding behavior of $SiO_{2}$ thin film and glass during VCR head fabrication was investigated, varying the surface roughness of substrate and the sputtering parameter. Insufficient fillings of grooves In the $SiO_{2}$ film with glass was postulated to give rise to the generation of bubble in the glass. The surface roughness of $SiO_{2}$ film was found to depend on that of substrate. The lower the deposition rate, the smoother the surface of film. The bubble free glass after bonding could be obtained using substrate polished with 0.05$\mu\textrm{m}$ $Al_2O_3$ powder under the sputtering condition of 10% oxygen pressure.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.680-686
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• 1997

Ultrafiltration and reverse osmosis were applied to produce soy-oligosaccharides from yeast fermented bean cooking water (BCW). The recovered total sugar by the ultrafiltration of bean cooking water on a cutoff molecular weight membrane of 20,000 and 5,000 was over 80%. The protein was removed up to 38% from the non-fermented BCW, 31% by S. cerevisiae KCTC 7039 and 21% by H. anomala KFRI 626. The recovery of oligosaccharides was above 70%, although fermented or non fermented bean cooking water was different on the recovery of oligosaccharides. The ultrafiltrated BCW was concentrated by reverse osmosis with respect to the volume concentration ratio (VCR). Total solid, total sugar, ash and protein contents increased up to VCR of 3.5 and then levelled off, showing that the optimum VCR was 3.5.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.200-214
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• 2000

In general, it is difficult to transmit a VBR video like MPEG efficiently since MPEG fames are construct with various size. To solve this problem, some bandwidth smoothing techniques are proposed which is based on the prefetching video data into the client buffer with low bandwidth allocation. However these techniques do not provide efficient bandwidth smoothing technology and transmission technique for interactive video services like VCR-like functionality. In this paper, we propose and evaluated a new bandwidth allocation mechanism for interactive video services which has VBR traffic characteristics such a MPEG. This technique provides VCR-like functionality which is not supported on previous techniques and also maximizes the bandwidth utilization when interactive video services are provided. Through our experimental, we prove that the proposed technique dramatically decreases a traffic and guarantee the continuous playback simulaneously.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.435-447
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• 2004

For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.299-310
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• 2000

In this paper, we designed and implemented a personal VOD server using multi-thread for the real-time services of video data to the users. The system consists of service manager, disk manager, and network manager. The service manager controls the user admission to the system using the VBR(Variable Bit Rate) characteristics of MPEG (Moving Picture Experts Group) video data. The disk manager provides the functions for VCR-like operations. The disk manager reads blocks from the disk by the size of GOP(Group of Pictures) and buffers the data to the user's thread. The network manager uses TCP/IP for the communication between the server and the client. The communication starts from the client and the VOD server must respond to this request. The implemented personal VOD system shows an acceptable performance.