• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.197-203
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• 2010

The problem of location awareness in wireless sensor networks where nodes use GPS (Global Positioning System), remains challenging problem, when considering the required large energy consumption during the localization phase. In this paper we designed hardware for GPS based localization and propose a framework, called ELS, to consume low cost energy. In the ELS framework, sensor nodes are equipped with GPS. Because GPS spends large energy for position awareness, conventional localization algorithms cannot use GPS-device. We try to find a solution for efficient energy expenditure of GPS. Finally, we derive optimal transmission power of GPS data and a scheme of localization through experiment and simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.338-344
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• 2002

In this paper, neural network force tracking control is proposed. The conventional impedance function is reformulated to have direct farce tracking capability. Neural network is used to compensate for all the uncertainties such as unknown robot dynamics, unknown environment stiffness, and unknown environment position. On line training signal of farce error for neural network is formulated. A large x-y table is built as a test-bed and neural network loaming algorithm is implemented on a DSP board mounted in a PC. Experimental studies of farce tracking on unknown environment for x-y table robot are presented to confirm the performance of the proposed technique.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.113-114
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• 2008

In this paper, binary pulse-position modulation (2PPM) time-hoping (TH) ultra-wideband (UWB) system is applied to multiple input multiple output (MIMO) system using vertical bell lab layered space-time (V-BLAST) structure to achieve high-data-rate communications. This UWB-MIMO system and its receivers are analyzed, and its BER performances are evaluated. In the receiver, various MIMO detection algorithms such as zero-forcing (ZF), ZF-ordered successive interference cancellation (OSIC), minimum-mean-square-error (MMSE), MMSE-OSIC and maximum likelihood (ML) are comparatively studied.

• MALSORI
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• no.39
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• pp.15-24
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• 2000

This study aims to reexamine Korean Lenis Stop Voicing (henceforth, LSV) and to specify its phonetic conditions in phonetic terms. LSV optionally occurs within certain prosodic domains. They are called 'Malthomak'(Lee, 1996),'phonological phrase'(Kang, 1992), or 'accentual phrase'(Jun, 1993). On the basis of Jun's phrasing, this study focuses on the more specific phonetic conditions of LSV in the accentual phrase medial position, sub-classifying voicing as complete and partial. The results shows that whether the stops become completely voiced or partially voiced was determined by the various phonetic environments, such as adjacent segments and following intonational phrase boundaries. It is shown that the conditions of LSV should be described in terms of more detailed phonetic environments and that they could be used in predicting the class of voicing.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1082_1083
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• 2009

This paper proposes two-mode tracking system control algorithm to improve efficiency of PV system. Two-mode control algorithm tracks sun position using sensor method and program method with insolation condition. Also, in this case that insolation is very low, tracking system is controlled by environment mode to reduce the power loss. Proposed algorithm is applied the PV system and analyzes the generation value. And this algorithm proves the validity of this paper through the experimental result.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2251_2252
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• 2009

In this paper, an attempt has been made by incorporating variable wheel arrangement for a car-like robot. In this scheme, the car-like robot controls its body height and the length of forward and backward wheels while driving in omni-direction. Experimental results show that the proposed car-like robot with wheel arrangement variable structure presents effectiveness of several situations.(a. left and right turn, b. longitudinal and latitudinal parking, c. control of body height and the length of forward and backward wheels, d. passing over obstacles, e. adaptive cruise control.)

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1705_1706
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• 2009

기존 레지스터컨트롤러는 스케닝 헤드를 이용하여 인쇄를 하였으나 기존 인쇄방법은 펄스의 시간과 시간차를 이용하여 인쇄물의 에러의 차이를 보여줬다. 기존의 스케닝 헤드식 레지스터컨트롤러는 오차가 100[um]인 반면에 영상처리를 이용함으로인해 오차의 범위를 10[um]로 보다 정밀하게 인쇄를 할 수 있으며 이는 전자인쇄 오차 범위안에 들어간다. 그리하여 본 논문에서는 영상처리를 이용하여 오차의 범위를 10[um] 이내로 들어오게 하는 위치제어알고리즘에 대하여 연구하려 한다.

• Korean Management Science Review
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• v.27 no.3
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• pp.33-41
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• 2010

A lot of researches find negative volatility risk premium in options market. We can make a trading profit by exploiting the negative volatility premium. This study proposes negative volatility risk premium hypotheses in the KOSPI 200 stock price index options market and empirically test the proposed hypotheses with intra-day short straddle strategy. This strategy sells both at-the-money call option and at-the-money put option at market open and exits the position at market close. Using MySQL 5.1, we create our database with 1 minute option price data of the KOSPI 200 index options from 2004 to 2009. Empirical results show that negative volatility risk premium exists in the KOSPI 200 stock price index options market. Furthermore, intra-day short straddle strategy consistently produces annual profits except one year.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.103-107
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• 2006

In order to develop hydroquinone analogues for topical delivery, a structure-activity relationship study has been performed. A series of 2-substituted hydroquinones were tested for their ability to inhibit mushroom tyrosinase, alter melanin release and exert cytotoxicity in B6-F10 melanocytes. The electronic property of the 2-substituents did not affect the tyrosinase inhibition nor melanocyte toxicity. However, lipophilicity did affect to some degree the tyrosinase inhibition. The discrepancy in the structure-activity relationship may be due to the poor aqueous solubility of select analogues. Compounds with steric bulk at the 2-position seems to be less soluble, not enabling the analogue to interact effectively with the tyrosinase enzyme. Among the analogues tested, 2-isopropyl hydroquinone seems to be the most promising candidate for topical delivery, being the least toxic analogue with moderate melanin release inhibition.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.131-137
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• 1995

The alkaline phosphatase (K-ALPase) gene of Kluyveromyces fragilis has been cloned (1) and determined its base sequences (2) previously in our laboratory. When the K-ALPase gene was expressed in Escherichia coli and Saccharomyces cerevisiae, it showed a constitutive activity in E. coli, and a derepressed activity in S. cerevisiae in phosphate-limited medium. Northem hybridization experiment was performed to elucidate the transcription level of the K-ALPase gene. Northern experiment showed that transcription level of K-ALPase gene in S. cerevisiae was higher in phosphate depletion, but it was higher in high phosphate medium than in phosphate limited medium in K. fragilis. The transcription initiation site of the K-ALPase gene was determined by primer extension analysis. It matched nucleotide position - 169 in relation to the putative trnslational start site.