• Journal of the Korean BIBLIA Society for library and Information Science
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• v.21 no.1
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• pp.89-103
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• 2010

Study on users which was done centering information approach, acquisition and interoperability between users and information systems need to be studied in the perspective of information behavior including information acquisition and sharing behavior in the changing information environment. In order to analyze users' information acquisition and sharing behavior's demands, motives and processes in libraries and internet environments, integrated approach of both qualitative and quantitative study were tried by applying Wilson's information behavior concept. Plans for the improvement of information services were suggested on the basis of integrative analysis.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.120-124
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• 2017

In this paper, effect of antenna diversity on pseudorandom noise (PN) code acquisition performance is analyzed and simulated for a direct sequence/code division multiple access (DS/CDMA) overlay system where a CDMA user and a narrowband user coexist in the same frequency band. From the simulation results, it is shown that the antenna diversity is very effective in improving the PN acquisition performance. The results of this paper can be applied to design of synchronization scheme for a DS/CDMA overlay environment.

• The Journal of Information Systems
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• v.14 no.2
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• pp.173-189
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• 2005

Recently, Korean software industry has enjoyed fast growth, thus phenomenon drew attention to the need for more precise and standardized cost estimation system for software development. However, many obstacles exist in achieving a more precise and universally applicable cost measurement. These obstacles include : (1) the intangible nature of intellectual efforts, (2) lack of cost standards, (3) lack of quantitative yardstick to determine the potential complication, (4) lack of both cost monitoring during development and coordinating between acquisition process and cost estimation. The purpose of this study is to facilitate software development cost estimation considering acquisition process that will meet korean user's needs, and to create better models that will be cost for software development particularly for Korean environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.335-336
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• 2006

Compound semiconductor manufacturing environment also has been emerged as mass customization and open foundry service so integrated manufacturing system is needed. In this study, we design data acquisition system of compound semiconductor fabrication that has monitoring and control of process. The developed DAS is consisted of key-in system inputted by operator and automatic acquisition system by GEM protocol. And we implemented them in the actual compound semiconductor. It is expected that using developed system would offer precise process information to buyer, reduce a lead-time, and obey a due-dates and so on.

• Journal of Intelligence and Information Systems
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• v.1 no.2
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• pp.123-137
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• 1995

Most of solution methods in scheduling attempt to generate good solutions by either developing algorithms or heuristic rules. However, scheduling problems in the real world require considering more factors such as multiple objectives, different combinations of heuristic rules due to problem characteristics. In this respect, the traditional mathematical a, pp.oach showed limited performance so that new a, pp.oaches need to be developed. Expert system is one of them. When an expert system is developed for scheduling one of the most difficult processes faced could be knowledge acquisition on scheduling heuristics. In this paper we propose a method for the acquisition of knowledge on the selection of scheduling heuristics using Dempster-Shafer Theory(DST). We also show the examples in the multi-objectives environment.

• Journal of Family Resource Management and Policy Review
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• v.9 no.1
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• pp.1-15
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• 2005

This study was designrd to determination factors of purchase expansion for environment-friendly agricultural products on consumers. The 310 subjects formatted questionnaires were analyzed to frequency, percentage, descriptives, T-test and logistic regression by SPSS WIN 10.0. The results were as follows : First, it is proved that degree of cognition, standard of information acquisition, basis of valuation were significant variables, Second, it is revealed that the producer and the direct deal, the consumer organization's co-op and the food floor of large-sized discount hoarded goods for purchase places of environment-friendly agricultural products were significant variables. Third, it is proved that reduction in a price the improvement matter for purchase expansion of environment-friendly agricultural products was determination factors. Forth, it is proved that age and income for purchase expansion of environment-friendly agricultural products was determination factors. Accordingly, we should find the positive factors of purchase and consumption that it will become an important subject for environment-friendly agricultural products on consumers.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.58-68
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• 2000

In this paper we introduce the correlation-aided distributed sample acquisition (CDSA) scheme for fast cell search in IMT-2000 W-CDMA cellular system. The proposed scheme incorporates the state symbol correlation process into the comparison-correction based synchronization process of the original DSA scheme to enable fast acquisition even under very poor channel environment. for its realization, each mobile station (MS) has to store in its memory a set of state sample sequences. which are determined by the long-period scrambling sequences used in the system and the sampling interval of the state samples. CDSA based cell search is carried out in two stages : First, the MS first acquires the slot timing by using the primary synch code (PSC) and then identifies the igniter code which conveys the state samples of the current cell . Secondly. the MS identifies the scrambling code and frame timing by taking the comparison-correction based synchronization approach and, if the identification is not done satisfactorily within preset time. it initiates the state symbol correlation process which correlates the received symbol sequence with the pre-stored state sample sequences for a successful identification. As the state symbol SNR is relatively high. the state symbol correlation process enables reliable synchronization even in very low chip-SNR environment. Simulation results show that the proposed CDSA scheme outperforms the 3GPP 3-step approach, requiring the signal power of about 7 dB less for achieving the same acquisition time performance in low-SNR environments. Furthermore, it turns out very robust in the typical synchronization environment where large frequency offset exists.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1087-1094
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• 2008

In this paper, we propose the acquisition method of the Cyclic-Prefix CDMA using Good-Autocorrelation-Sequence (GAS-CP-CDMA) system. The sequences for GAS-CP-CDMA are m-sequence and constant amplitude zero autocorrelation code (CAZAC) with good autocorrelation property. The GAS-CP-CDMA system is proposed for interference cancellation in multi-user and -path environment in co-cell. However, the reliable initial acquisition in multi-path fading channel and multi-user system environment is crucial. In this paper, non-coherent power detector and threshold value are used for discriminating signal acquisition. The sequence used for computer simulation is CAZAC. The simulation results show proper threshold value depends on the number of users. Through the computer simulation, we draw setting up method of the optimum threshold value for the GAS-CP-CDMA system.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.646-652
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• 2013

EU's Galileo project is a market-based GNSS (Global Navigation Satellite System) that is under development. It is expected that Galileo will provide the positioning services based on new technologies in 2020s. Because Galileo E1 signal for OS (Open Service) shares the same center frequency with GPS L1 C/A signal, CBOC (Composite Binary Offset Carrier) modulation scheme is used in the E1 signal to guarantee interoperability between two systems. With E1 signal consisting of a data channel and a pilot channel at the same frequency band, there exist several options in designing signal acquisition for Assisted-Galileo receivers. Furthermore, compared to SNR worksheet of Assisted-GPS, some factors should be examined in Assisted-Galileo due to different correlation profile and code length of E1 signal. This paper presents SNR worksheets of Galileo E1 signals in E1-B and E1-C channel. Three implementation losses that are quite different from GPS are mainly analyzed in establishing SNR worksheets. In the worksheet, hybrid long integration of 1.5s is considered to acquire weak signal less than -150dBm. Simulation results show that the final SNR of E1-B signal with -150dBm is 19.4dB and that of E1-C signal is 25.2dB. Comparison of relative computation shows that E1-B channel is more profitable to acquire the strongest signal in weak signal environment. With information from the first satellite signal acquisition, fast acquisition of the weak signal around -155dBm can be performed with E1-C signal in the subsequent satellites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6A
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• pp.685-692
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• 2008

In this paper, we propose a timing recovery loop for Inmarsat mini-m system downlink receiver. Inmarsat mini-m system requires a timing recovery loop which is robust in frequency offset and has fast acquisition because Inmarsat mini-m system specification requires frequency tolerance is required of ${\pm}924$ Hz (signal bandwidth: 2.4 kHz) and acquisition time of UW (Unique Word) signal duration (15ms).Therefore, we propose a timing recovery loop which is suitable for Inmarsat mini-m system. The proposed timing recovery loop adopted noncoherent UW detector and differential ELD which applied differential UW signal for stability and fast acquisition in frequency offset environment. Simulation results show that the proposed timing recovery loop has stable operation and fast acquisition in frequency offset environment for the system.