• Journal of the Korean earth science society
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• v.37 no.5
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• pp.277-285
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• 2016

We introduce a depth scaling strategy to improve the accuracy of frequency-domain elastic full waveform inversion (FWI) using the new pseudo-Hessian matrix for seismic data without low-frequency components. The depth scaling strategy is based on the fact that the damping factor in the Levenberg-Marquardt method controls the energy concentration in the gradient. In other words, a large damping factor makes the Levenberg-Marquardt method similar to the steepest-descent method, by which shallow structures are mainly recovered. With a small damping factor, the Levenberg-Marquardt method becomes similar to the Gauss-Newton methods by which we can resolve deep structures as well as shallow structures. In our depth scaling strategy, a large damping factor is used in the early stage and then decreases automatically with the trend of error as the iteration goes on. With the depth scaling strategy, we can gradually move the parameter-searching region from shallow to deep parts. This flexible damping factor plays a role in retarding the model parameter update for shallow parts and mainly inverting deeper parts in the later stage of inversion. By doing so, we can improve deep parts in inversion results. The depth scaling strategy is applied to synthetic data without lowfrequency components for a modified version of the SEG/EAGE overthrust model. Numerical examples show that the flexible damping factor yields better results than the constant damping factor when reliable low-frequency components are missing.

• Journal of Information Technology Applications and Management
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• v.10 no.3
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• pp.23-44
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• 2003

It is needed to search the electronic commerce standardization and to analysis its policies to meet the international situations strategically and forecast the technology surroundings for electronic commerce. This study aims at searching the current state of electronic commerce standardization and analyzing policies on electronic commerce by the driving subject, that is, government and private organization, major countries, and standard classifications of electronic commerce technologies such as e-documents, e-catalog, e-payment, and e-process. The government and private organizations get information for the current state and policies for standardization on electronic commerce and put them practical use to make policies and strategy applications.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.11
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• pp.528-536
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• 2001

This paper proposes a method of solving a unit commitment problem using parallel tabu search(PTS) approach. Tabu search is a heuristic optimization method that has the tabu list to control the search process. To improve the searching ability of a global solution, we used a method of exchanging solutions among connected processors as a diversification strategy, and to reduce the computation time, a new evaluating method was proposed which evaluates only a changed par. To show the usefulness of the proposed method, we simulated for 10 units system and 110 units system. Numerical results show improvements in the generation costs and the computation time compared with other conventional methods.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1044-1047
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• 2005

In this paper, we present the strategy of object search for distributed autonomous robotic systems (DARS). The DARS are the systems that consist of multiple autonomous robotic agents to whom required functions are distributed. For instance, the agents should recognize their surrounding at where they are located and generate some rules to act upon by themselves. In this paper, we introduce the strategy for multiple DARS robots to search a hidden object at the unknown area. First, we present an area-based action making process to determine the direction change of the robots during their maneuvers. Second, we also present Q learning adaptation to enhance the area-based action making process. Third, we introduce the coordinate system to represent a robot's current location. In the end of this paper, we show experimental results using hexagon-based Q learning to find the hidden object.

• Journal of Information Technology Applications and Management
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• v.20 no.1
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• pp.197-216
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• 2013

Despite the vast potential opportunities of RFID technology in various industrial applications, deployment of RFID applications is rather limited to meet a large industrial demand in Korea. We conducted in-depth case study to organize the RFID applications in business model framework in order to provide practical insights for the development of innovative RFID applications. Throughout extensive searching for RFID applications in literature, web, news, and policy reports, we first classified passive RFID applications, mobile RFID applications, and active RFID applications. Value creation and implementation issues are compared and analyzed for each of RFID applications using Afuah and Tucci business model. This study can contribute in establishing future development of RFID technology, competitive business strategy, and government policy to stimulate Korea RFID industry.

• Journal of Korea Port Economic Association
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• v.22 no.2
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• pp.109-133
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• 2006

The Study investigated economic effects and the conditions in the public Shipping e-marketplace. For efficient operation of the public Shipping e-marketplace, this study analyzed how do the participation and community actualize in the public Shipping e-marketplace actualize. According to the research results of the Shipping Cooperations, For Promoting participation in the public Shipping e-marketplace, the Cyber-intermediary operating public Shipping e-marketplace provides timely shipping information, needs publicity strategy generating more benefits than offline transaction, and gives a conviction of the searching costs and transaction costs decrease. Second For promoting community, the Cyber-intermediary must playa major role in electronic community and drive forward continuous publicity strategy in the public Shipping e-marketplace.

• Journal of the Korean Home Economics Association
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• v.41 no.12
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• pp.103-116
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• 2003

It's very important to control their buying impulse for consumers surrounding in the very aggressive marketing strategies and materialistic socio-economic system. This study was to explore consumer's strategies to resist their buying impulses. The results from content analysis of interview data show various strategies and very similar to the self-control strategies of literature. The pre-stage strategies to resist buying impose were avoidances marketing strategies, pre-commitments, searching informations and bringing shopping lists and etc. The post-stage strategies were suspicions about marketing messages, considerations of negative outcomes, postponements, economic cost assessments, substitutions and etc. Developments and assessments of education programs to enhance consumer's self-control were needed.

• The Research Journal of the Costume Culture
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• v.16 no.2
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• pp.205-218
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• 2008

This study was to develop a fashion internship pragmatic program for college students. Preceded researches were reviewed and some case studies were used for this study. The results of this study were as follows : Pragmatistic program has 6 steps such as preperation, introduction, selection, operation, reputation, management. pre-internship schedule, resume and self-introduction form, preparing for the interview and details, how to write a follow up letter after the interview, advise during the intern period, 7 contents that you should include in the final report, Presentation Strategy, SWOT analysis table were included in this study. So this study would be helpful for the college students who are searching for internships and jobs.

• Journal of Ecology and Environment
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• v.29 no.1
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• pp.49-53
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• 2006

The fiddler crab, Uca lactea, which lives on intertidal mudflats in Korea, exhibits both burrow mating and surface mating. We observed 17 cases of surface mating that occurred on Ganghwa Island, South Korea. Most surface-mating males did not build semidomes, structures that attract searching females for burrow mating. Based on the conclusion of a previous study that semidome building is condition-dependent, we suggest that food availability may influence the mating tactic of this species. In addition, there was a strong correlation between the carapace size of both sexes that surface-mated, which suggests that males use body size of females as a mating cue.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.4
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• pp.161-171
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• 2015

Alternative binary offset carrier (AltBOC) signals can be approximated by four synchronized direct sequence spread spectrum (DSSS) signals, each pair of which is a quadrature phase shift keyed (QPSK) signal at a different frequency. Therefore, depending on the strength of an incoming AltBOC signal, an acquisition technique can reduce the mean acquisition time (MAT) by searching the four DSSS signals asynchronously; the search for each of the four DSSS signals can start at one of the evenly separated hypotheses on the two-dimensional hypothesis space. And detection sensitivity can be improved by multiple levels when different numbers of search results for the same hypothesis are combined. In this paper, we propose a fast AltBOC acquisition technique that has an asynchronous search strategy and efficiently utilizes the output of the four search results to increase the sensitivity level when sensitivity improvement is needed. We provide a complete theoretical analysis and demonstrate with numerous Monte Carlo simulations that the MAT of the proposed technique is much smaller than conventional AltBOC acquisition techniques.