• The KIPS Transactions:PartD
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• v.14D no.1 s.111
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• pp.107-120
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• 2007

When it tomes to IT investment, it's a challenge for the management to make the right decision. Unlike investment in other business area, it's hard to measure direct cost vs. effect in IT business. To validate the investment in IT, it is required to establish objective assessment system that both provider and beneficiary of information can accept, and it is also required to suggest an assessment tool of fixed quantity that includes measuring standards and method for the economic effect of new investment. This study, therefore, has developed IT ROI Methodology that can prove investment validity by accepting the strong points of the existing models while complementing their weak points and by analyzing IT Investment and IT Efforts. It also has built an IT ROI System that reflects the methodology which is applied to 21 companies of 5 business categories. This system is designed to provide effective and objective decision-making tool for IT investment by proving what positive impacts IT could have on business activities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.75-80
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• 2008

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.79-87
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• 2003

Application of combustion stabilization devices such as baffle and acoustic cavity to liquid propellant rocket engine is investigated to suppress high-frequency combustion instability, i.e., acoustic instability. First, these damping devices are designed based on linear damping theory. As a principal design parameter， damping factor is considered and calculated numerically in the chambers with/without these devices. Next, the unbaffled chambers with/without acoustic cavities are tested experimentally for several operating conditions. The unbaffled chamber shows the peculiar stability characteristics depending on the operating condition and it is found to have small dynamic stability margin. As a result, the acoustic cavity with the present design has little stabilization effect in this specific chamber. Finally， stability rating tests are conducted with the baffled chamber, where evident combustion stabilization is observed, which indicates sufficient damping effect.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.595-601
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• 2006

This study presents an ultrasonic location awareness system for the ubiquitous computing with absolute position. The flight time of ultrasonic waves is determined by a period detecting technique which is able to extend the sensing range compared with traditional methods. For location awareness, ultrasonic waves are sent successively from each ultrasonic transmitter and synchronized by radio frequency (RF) signal, where the transmitting part is fixed and the receiving part is movable. To expand the recognizing range, cell matching technique and coded ultrasonic technique are introduced. The experimentation for various distances is accomplished to verify the used period detecting technique of U-SAT system. The positioning accuracy by using cell matching is also verified by finding the locations of settled points and the usability of coded ultrasonic technique is verified. As a result, the possibility of ultrasonic location awareness system for the ubiquitous computing can be discussed as a pseudo-satellite system with low cost, a high update rate, and relatively high precision, in the places where GPS is not available.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.62-67
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• 2020

The European Aviation Safety Agency (EASA) legislates the CS-E (Certification Specification-Engine) for type certification of aircraft engines. According to the CS-E, engine manufacturers (type certificate holders) the need to show compliance of continued airworthiness of an engine during the overhaul, and the Accelerated Mission Test (AMT) is usually accepted as means of compliance. As a part of the Korean Civil Helicopter program, the engine has been developed with foreign manufacturers to achieve the EASA engine type certificate. In this study, the AMT procedure is planned for the engine to be certified by the EASA, and AMT cycles are also established to meet airworthiness requirements of the CS-E in consideration of the engine design and operation characteristics.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.177-185
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• 2007

Lately, it is a trend that diffusion of Mobile Information Appliance that do various function by development of IT technology. There is function that do more convenient and efficient exchange information and business using mobile phone that is Mobile Information Appliance, but disfunction that is utilized by pointed end engineering data leakage, individual's privacy infringement, threat, etc. relationship means to use mobile phone is appeared and problems were appeared much. However, legal research of statute unpreparedness and so on need research and effort to prove delete, copy, integrity of digital evidence that transfer secures special quality of easy digital evidence to objective evidence in investigation vantage point is lacking about crime who use this portable phone. It is known that this Digital Forensic field is Mobile Forensic. In this paper. We are verify about acquisition way of digital evidence that can happen in this treatise through mobile phone that is Mobile Forensic's representative standing and present way to prove integrity of digital evidence using Hash Function.

• Progress in Medical Physics
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• v.10 no.1
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• pp.47-54
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• 1999

Purpose: To verify the BRW coordinates of target located within the limit of XKnife hardware, and to verify the successful transfer of image data, rod detection, anatomical structure when CT images are transferred into a XKnife computer. Materials and Methods: Target coordinates of 13 patients were calculated by SCS1 computer through the rod image on the console screen and film. BRW coordinates of target and landmark calculated by SCS1 computer were compared to those acquired by XKnife localizer. Results : Vertical components of BRW coordinates of target for 13 patients are larger than -50 mm, and then the vertical components of BRW coordinates of target are localized within the limit of XKnife hardware. Average differences between XKnife and SCS1 for BRW coordinates of target and landmark were within 1 mm for AP and LAT components, 0.5 mm for VERT component. Conclusion : It was verified that the SCS1 computer is adequate tool to calculate BRW coordinates of target quickly. And by the comparison between SCS1 computer and XKnife localizer, it was verified that the image transfer into the XKnife computer was performed successfully.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.137-146
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• 2020

The purpose of this study is to confirm the moderating effect of the 'IRrelevance Processing'(IRP) on the relationship between decision maker's openness and business problem solving creativity (BPSC). In order to confirm the psychological mechanism of BPSC and openness, we developed the irrelevance processing. In particular, the creativity in this study is different from the general creativity studied in psychology. BPSC is a study with practical value applied in the management environment. The results showed that openness of the decision maker was correlated with the BPSC, and that the irrelevance processing was a psychological mechanism to moderating effects relationship between openness of decision makers and BPSC. This paper proved the correlation between the propensity of decision makers and BPSC, and contributed to the study of corporate creativity by identifying the psychological mechanisms.

• KSCI Review
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• v.15 no.1
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• pp.37-46
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• 2007

Lately, is trend that diffusion of Mobile information appliance that do various function by development of IT technology is increasing much. There is function that do more convenient and efficient life and business using portable phone that is Daepyo?? of Mobile information appliance, but dysfunction that is utilized by Beopjoe of pointed end engineering data leakage, individual's privacy infringement, threat and threat etc. relationship means to use Mobile Phone is appeared and problems were appeared much. However, legal research of statute unpreparedness and so on need research and effort to prove delete, copy, integrity of digital evidence that transfer secures special quality of easy digital evidence to objective evidence in investigation vantage Point is lacking about crime who use this portable phone. It is known that this digital Forensic field is Mobile Forensic. Is purposeful to verify actually about acquisition way of digital evidence that can happen in this treatise through portable phone that is Mobile Forensic's representative standing and present way to prove integrity of digital evidence using Hash Function.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.21-29
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• 2001

In order to detect the precise port/starboard direction of arrival of target signal in real noisy ocean environments, Inverse beamforming (IBF) algorithm is surveyed theoretically and the detection performances of IBF are analyzed with simulations. Cardioid Inverse beamforming algorithm was proposed for port/starboard discrimination and the performance was studied with simulations. It is shown that IBF has a 3dB array gain advantage over Conventional beamforming (CBF) under ideal conditions. This 3 dB advantage is proven theoretically and illustrated with simulations. The fact that the IBF beamwidth is narrower than the CBF beamwidth by a factor of 0.68 proves the performance of defection and spatial resolution improvement. Comparing the simulation results of Cardioid Inverse beamforming and Conventional Cardioid beamforming, it is shown that Cardioid Inverse beamformer has enhanced performance in minimum detection level, detection accuracy and resolution. Due to the results of moving target bearing detection test in endfire, it is shown that Cardioid Inverse beamformer has better performance, comparing the Conventional Cardioid beamformer.