• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.759-765
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• 2011

In this paper, we proposed fast stream cipher MS64 for use mobile that it is secure, fast, and easy to implement software. The proposed algorithm use the fast operating 213-bit arithmetic shift register(ASR) to generate a binary sequence and produce 64-bit stream cipher by using simple logical operation in non linear transform. MS64 supports 128-bit key in encryption algorithm and satisfy with the safety requirement in modern encryption algorithm. In simulation result shows that MS64 is faster than a 32-bit stream cipher SSC2 in the speed of operation with small usage of memory thus MS64 can be used for mobile devices with fast ciphering.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.700-702
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• 2004

MS(Mobile Station)가 HSDPA(High Speed Downlink Packet Access)를 지원하는 W-CDMA(Wideband Code Division Multiple Access)망과 IEEE 802.16e를 지원하는 HPi(High Speed Portable Internet)망 사이를 이동할 때 발생하는 vertical 핸드오프 시 MS는 이전 경로 상에서 받지 못한 데이터를 새로운 경로로 넘겨받아 데이터가 순서대로 손실 없이 착신됨을 보장받아야 한다. 이것은 재전송의 오버헤드를 줄이는 이점이 있다. 또한 vertical 핸드오프 시 새로운 망에 MS가 재구성되어지는 과정이 포함되어야 한다. 이를 위해 본 논문에서는 vertical 핸드오프 시 이전 경로 상에서 받지 못한 데이터를 순서대로 넘겨받는 것과 새로운 망에 적용되는 MS 재구성에 관련된 프로토콜을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.721-723
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• 2004

두 개의 서로 다른 통신망, HSDPA(High Speed Downlink Packet Access)를 지원하는 W-CDMA망과 IEEE 802.16e를 지원하는 HPi(High Speed Portable Internet)망을 동시에 지원하는 이중모드 BS(Base Station)에서 MS(Mobile Station)가 현재 사용하고 있는 통신 프로토콜 상에서 사용자 폭주나 망의 이상으로 인한 QoS 저하를 탐지해서 더 좋은 QoS를 보장받도록 하기 위해서 MS를 재구성한다. 본 논문에서는 MS 재구성 과정 중에 이전 경로 상에서 받지 못한 데이터를 새로운 경로에서 손실 없이 받을 수 있도록 하기 위한 이중모드를 지원하는 기지국 내에서의 핸드오프 기법을 제안하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4015-4033
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• 2015

The future mobile networks consist of hyper-dense heterogeneous and small cell networks of same or different radio access technologies (RAT). Integrating mobile networks of different RATs to provide seamless and smooth mobility service will be the target of future mobile converged network. Generally, handover from high-speed networks to low-speed networks faces many challenges from application perspective, such as abrupt bandwidth variation, packet loss, round trip time variation, connection disruption, and transmission blackout. Existing inter-RAT handover solutions cannot solve all the problems at the same time. Based on the high-layer convergence sublayer design, a new receiver-aided soft inter-RAT handover is proposed. This soft handover scheme takes advantage of multihoming ability of multi-mode mobile station (MS) to smooth handover procedure. In addition, handover procedure is seamless and applicable to frequent handover scenarios. The simulation results conducted in UMTS-WiMAX converged network scenario show that: in case of TCP traffics for handover from WiMAX to UMTS, not only handover latency and packet loss are eliminated completely, but also abrupt bandwidth/wireless RTT variation is smoothed. These delightful features make this soft handover scheme be a reasonable candidate of mobility management for future mobile converged networks.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.93-100
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• 2008

A liquid chromatographic method with tandom spectrometric detection (LC/MS/MS) for the simultaneous determination of doxifluridine and its active metabolite, 5-fluorouracil (5-FU) was developed over the concentration range of $5{\sim}2000$ ng/ml, respectively. Doxifluridine, 5-FU and internal standard, 5-chlorouracil (5-CU), were extracted from liver and intestine tissue via protein precipitation. Acetonitrile was used as the extraction solvent and the supernatant was evaporated and reconstructed in mobile phase. Optimum chromatographic separation was achieved on a Agilent Zorbax $C_{18}$ ($100\;mm{\times}2.1\;mm$, $3.5\;{\mu}m$) column with mobile phase run in isocratic with methanol : water (20 : 80, v/v). The flow rate was 0.2 ml/min with total cycle time of 5 min. The lower limit of quantification was validated at 5.0 ng/ml of liver and intestine tissue, for both doxifluridine and 5-FU, respectively. The intra-day and inter-day precision and accuracy of quality control (QC) samples were <11% coefficient of variation and <7% relative error from theoretical concentration for both analytes. In addition, the special designed stability study was performed, because the metabolism of doxifluridine occurs spontaneously even in ice bath for monkey liver. The stability of doxifluridine in liver and intestine of monkey and beagle dog was compared. It was found that bioanalytical validation could not be performed for the monkey liver; however, beagle dog's liver has relatively low speed of metabolism compared to monkey liver and instead of monkey liver, beagle dog's liver could be used for the validation. Bioanalytical validation could be performed in monkey intestine. Eventually, this developed method for liver and intestine will be useful in support of the toxicokinetic and pharmacokinetic studies of doxifluridine and 5-FU.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1B
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• pp.1-7
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• 2008

In group location management, when a transportation system(TS) with multiple mobile subscribers(MSs) changes location area(LA), location management is performed by group location registration by TS, instead of individual location registrations by MSs. In previous works, although it is assumed that LA in group location management is the same as that in individual location management, it is not appropriate to assume the same sized LAs since MSs in a TS have different characteristics from MSs which are not in a TS from the aspect of the speed and aggregate call arrival rates. Thus, in this paper, we propose an efficient location management scheme based on individual and group location managements with different sized LAs, and the performance of the proposed scheme is analyzed from the aspect of signaling cost at the wireless interface. Results reveal that the proposed scheme outperforms the conventional scheme by selecting an appropriate sized LA for group location management.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.5
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• pp.53-63
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• 2019

To provide a hand gesture interface through deep learning in mobile environments, research on the light-weighting of networks is essential for high recognition rates while at the same time preventing degradation of execution speed. This paper proposes a method of real-time recognition of written characters in the air using a finger on mobile devices through the light-weighting of deep-learning model. Based on the SSD (Single Shot Detector), which is an object detection model that utilizes MobileNet as a feature extractor, it detects index finger and generates a result text image by following fingertip path. Then, the image is sent to the server to recognize the characters based on the learned OCR model. To verify our method, 12 users tested 1,000 words using a GALAXY S10+ and recognized their finger with an average accuracy of 88.6%, indicating that recognized text was printed within 124 ms and could be used in real-time. Results of this research can be used to send simple text messages, memos, and air signatures using a finger in mobile environments.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.323-330
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• 2006

This paper proposes a handoff time decision mechanism to utilize resource efficiently by using Differential Received Signal Strength Indicator (DRSSI). DRSSI can be used to predict the movement direction of Mobile Station (MS). In other words, DRSSI changes its sign (+ or -) when a MS changes movement direction. This mechanism maximizes resource availability of Base Station (BS) by predicting resource reservation of MS and by giving priority of resource to MS. It is possible when a BS predicts the behavior of MSs by monitoring the DRSSI of MSs in overlapped region among cells. Additionally, we show that our proposed mechanism has better handoff blocking probability than existing mechanism with numerical modeling and analysis.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.352-357
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• 2002

In CDMA cellular systems, a handoff process in which the mobile station (MS) can communicate with the target base station without interrupting the communication with the current base station makes contact with the target base station before it breaks with the station it is operating on. An MS requests a soft handoff to a neighbor base station (BS) whenever the pilot strength received from the neighbor BS exceeds the handoff threshold, even though the MS may not actually be approaching to the neighbor BS. Since two traffic channels have to assign to an MS during the soft handoff period, the utilization of traffic channels is wasted. Thus, an analysis of handoff rate is a key to understand and evaluate channel efficiency. In this paper, a simple and straightforward mathematical analysis method for evaluate obtaining direction-based soft handoff rate and the number of handoff calls in CDMA cellular systems is proposed.