• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.56-65
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• 2007

For supporting seamless service in NGN, various schemes for mobility are studying in ITU-T, 3GPP, IETF, and so on. Currently, mobility support schemes such as MIPv6, IP2, Q.MMF, IMS was introduced. However the performance analysis and comparison of all existing schemes is not examined as yet. That is, the existing mobility methods need to be compared according to same performance parameter. So, in this paper, we investigate and compare the performances of MIPv6, IP2, Q.MMF on latency during location registration. The latency in location registration is consider as cost and time. Then, the performance analysis of Q.MMF Case1 has shown the best performance as it is measured the minimum cost and time. Q.MMF Case1 is the location registration process in case that MT moves within a local network. As LLM in a access network manages the location of MT in this case, Q.MMF Case1 has lower location cost and time than other cases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1291-1297
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• 2004

In this paper, the new scheduling algorithm that supports the maximization of system throughput and the proportional fairness among non-real time traffic users is proposed in OFDMA wireless mobile communication systems. The concept of the proposed algorithm is based on the proportional fairness algorithm, which is deployed in 3GPP2, and sorting method. The proportional fairness algorithm is adapted to allocate the number of subcarrier per user. A sorting method is contributed to the maximization of system throughput in the practical allocation of subcarrier per user. Simulation results show that new algorithm had better performance than the max rate rule in case of fairness, higher throughput than the scheduling algorithm without sorting method. Even though the system throughput of the proposed algorithm is almost same with the iteration scheme using subcarrier swapping method between users, the computational time of the former is reduced up to 3 times than the latter.

• Mass Spectrometry Letters
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• v.2 no.4
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• pp.92-95
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• 2011

Pyrophosphates are the key intermediates in the biosynthesis of isoprenoids, and their concentrations could reveal the benefits of statins in cardiovascular diseases. Quantitative analysis of five pyrophosphates, including isopentenyl pyrophosphate (IPP), dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP), was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative ionization mode. After dilution with methanol, samples were separated on a 3 ${\mu}m$ particle multi-modal $C_{18}$ column ($50{\times}2$ mm) and quantified within 10 min. The gradient elution consists of 10 mM ammonium bicarbonate and 0.5% triethylamine (TEA) in water and 0.1% TEA in 80% acetonitrile was used at the flow rate of 0.4 mL/min. Overall recoveries were 51.4-106.6%, while the limit of quantification was 0.05 ${\mu}g$/mL for GPP and FPP and 0.1 ${\mu}g$/mL for IPP, DMAPP, and GGPP. The precision (% CV) and accuracy (% bias) of the assay were 1.9-12.3% and 89.6-111.8%, respectively, in 0.05-10 ${\mu}g$/mL calibration ranges ($R^2$ > 0.993). The devised LC-MS/MS technique with the multi-modal $C_{18}$ column can be used to estimate the biological activity of pyrophosphates in plasma and may be applicable to cardiovascular events with cholesterol metabolism as well as the drug efficacy of statins.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.5
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• pp.102-108
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• 2011

Support vector machines are well known for their outstanding performance in pattern recognition fields. One example of their applications is music/speech classification for a standardized codec such as 3GPP2 selectable mode vocoder. In this paper, we propose a novel scheme that improves the speech/music classification of support vector machines based on the second-order conditional maximum a priori. While conventional support vector machine optimization techniques apply during training phase, the proposed technique can be adopted in classification phase. In this regard, the proposed approach can be developed and employed in parallel with conventional optimizations, resulting in synergistic boost in classification performance. According to experimental results, the proposed algorithm shows its compatibility and potential for improving the performance of support vector machines.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.10-27
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• 2005

In this paper, we propose a high level design architecture of WCDMA(UMTS) base station modem and synchronization algorithms applied to the proposed architecture. Also analysis of each synchronization algorithm and performance evaluation of fixed point designed modem are shown. Since the target system is base station modem, each synchronization algorithm is designed for its stable operation. To minimize implementation complexity, optimum fixed point design for best operation of synchronization algorithms is performed. We performed symbol level link simulation with fixed point designed modem simulator for data rate of 12.2kbps, 64kbps, 144kbps, and 384kbps. We compared performance results to the minimum requirements specified in 3GPP TS 25.104(Release 5). Extensive computer simulation shows that the proposed modem architecture has stable operation and outperform the minimum requirement by 2 dB. The proposed modem architecture has been applied in the implementation of WCDMA reverse link receiver modem chip successfully.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.221-227
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• 2002

In this paper, in order to know the effect of the interference, we have analyzed the BER (Bit Error Rate) performance of the MUD(Multi-User Detector) employing HIC(Hybrid Interference Cancellation) scheme for the asynchronous WCDMA system based on 3GPP(3rd Generation Partnership Project) Spec. through the In this paper, in order to know the effect of the interference, we have analyzed the BER (Bit Error Rate) performance of the MUD(Multi-User Detector) employing HIC(Hybrid Interference Cancellation) scheme for the asynchronous WCDMA system based on 3GPP(3rd Generation Partnership Project) Spec. through the computer simulation. we have assumed Rayleigh fading channel. And we have compared its BER performance with SIC's(Successive Interference Cancellation) and with PIC's(Parallel Interference Cancellation), which are the representative schemes in the subtractive interference cancellation. From the results, it is shown that PlC or HIC is effective for high data-rate users and SIC of HIC for low data-rate users to eliminate the interference. Regardless of the data rate, it is reasonable to use the HIC structure for WCDMA system to satisfy all of users' services. The reason is that the SIC scheme in front of HIC can guarantee the performance of low power users to cancel the serious interference caused by the high power users, while PIC in the rear of it can guarantee the performance of high power users to cancel the interference caused by the low power users.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.31-34
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• 2003

본 논문에서는 3GPP2 에 명시된 전송파형 필터의 특성을 살펴보고, 기존 시스템에서 고려되지 않았던 전송파형 정합필터의 간섭특성에 의한 성능손실을 분석하고 실험을 통해 검증한다. 또한, FCC 의 요구사항을 만족하며 수신필터의 간섭을 크게 줄인 MMSE 수신필터를 제안하며, 실험과 분석을 통해 제안된 필터에 의해 SNR 손실이 크게 줄어드는 결과를 보인다.

• Information and Communications Magazine
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• v.22 no.9
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• pp.164-174
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• 2005

본 논문은 비동기 방식의 WCDMA 시스템에서 특히 IP Multimedia Subsystem의 도입과 함께 IP Security 기술이 어떤 형식으로 적용되어 표준화되고 있는지 기술동향을 알아보고자 한다. 현재 WCDMA 시스템에서의 IP Security 기술은 일반 네트워크 영역 보안 분야와 WLAN Inter-working 분야 그리고 IMS 보안 분야에 적용되고 있다. 가장 기본이 되는 네트워크 영역 보안은 3GPP 표준화 규격인 TS 33.210에 정의되어 있고, 이를 바탕으로 WLAN Inter-working 분야에서는 IKE version 2가 추가되었으며, IMS 보안 분야에서는 네트워크 영역 보안에서 정의된 Z 인터페이스를 이용하여 해당 트래픽에 대한 보안을 수행한다.

• Information and Communications Magazine
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• v.26 no.2
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• pp.62-68
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• 2009

본고에서는 FDMA/TDMA, CDMA, OFDM 시스템을 거치면서 셀간 간섭 회피, 평균화, 조정 기법들이 셀간 간섭 문제를 해결하기 위해 이용되어온 변화 과정을 알아보고, 3GPP LTE에서의 셀간 간섭 조정 기법의 이용을 위한 표준화 내용, 그리고 IMT-Advanced에서 셀간 간섭 문제를 해결하는 협력 통신으로의 진화를 살펴본다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.189-190
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• 2007

We propose an efficient internetworking model for fast handover between UMTS and WLAN networks. Mobility anchor (MA) is provided at the boundary between GGSN and PDG, under the 3GPP-proposed internetworking reference model. Such MA can enable authentication and session initialization before L2 handover of the mobile terminal, so that seamless and fast vertical handover could be possible.