• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.107-112
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• 2006

The previous acquisition method of GPS receiver for reference station adopts not only the coherent integration method but also the non-coherent integration method in order to enhance sensitivity under noisy environment. However, under noisy environment, the previous GPS signal acquisition method causes the non-coherent integration loss which is a major factor among losses that can be caused during GPS signal acquisition. The non-coherent integration loss also increases with the strength of the received noise. This paper has intention of analyzing the performance of the GPS signal acquisition method proposed to effectively enhance sensitivity of DGPS reference receiver under noisy environment. This paper presents that the proposed GPS signal acquisition method suppresses the non-coherent integration loss through post-processing simulation. Furthermore, with regard to the mean acquisition time, it is shown that the number of search cells of the proposed GPS signal acquisition method is much fewer than that of the previous GPS signal acquisition method.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.1
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• pp.96-102
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• 2004

For sensitivity enhancement, the general assisted-GPS acquisition method adopts not only the coherent accumulation technique but also the non-coherent accumulation technique since the long coherent accumulation period increases the number of frequency search cells. But the non-coherent accumulation technique causes tile squaring loss, which is a dominant factor among the acquisition losses of assisted GPS dealing with weak GPS signals. This paper derives the squaring loss of the previous assisted-GPS acquisition method and proposes an assisted-GPS acquisition method for solving the problem of squaring loss in weak signal environment. In this paper, it is explained that the proposed assisted-GPS acquisition method prevents the squaring loss using a coupled coherent accumulation technique and the number of search cells of the proposed assisted-GPS acquisition method is much smaller than that of the previous assisted-GPS acquisition method. Finally, through the simulation by the GPS simulator, the acquisition success rate of the proposed assisted-GPS acquisition method is compared with that of the previous assisted-GPS acquisition method and the acquisition improvements are shown in weak signal environment.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.8
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• pp.10-19
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• 1997

In this paper, perfodrmance of matched-filter (MF) acquisition scheme is analyzed for a direct-sequence/code-division-multiple-access (DS/CDMA) system in a microcellular environment. Mean acquistion time is used as a performance measure. It is demonstrated that acquisition performance is enhanced using interference suppression filter in a Rician fading channel. To apply for multiuser environments, multiple access interference is considered in the performance analysis. From the numerical results, it is shown that mean acquistion time decreases with the increasing SNR/chip, and acquisition performance is improved as the number of taps of interference suppression filter. It is also shown that mean acquisition time increases with the number of users in the system, and acquistion performance is degraded as the icrease of narrowband interference bandwidth. The analysis in this paper can be applied to a DS/CDMA overlay environment.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.185-188
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• 2000

In this paper, performance of a PN code acquisition scheme is analyzed and simulated for a DS/CDMA overlay system where a CDMA user and a narrowband user coexist in the same frequency band. To suppress the NBI, an interference suppression filter is employed at the receiver front-end. From the simulation results, it is shown that the interference suppression filter is very effective for suppression of the NBI and rapid PN code acquisition in a DS/CDMA overlay environment. It is also shown that the one-sided tap number of 5 fur interference suppression filter is sufficient to suppress the NBI.

• Journal of the military operations research society of Korea
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• v.28 no.1
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• pp.67-82
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• 2002

In this paper, we consider a rule of application of PRICE(Parametric Review of Information for Costing and Evaluation) model to the environment of Korean defense industry. The PRICE model which is a computer model to estimate the cost of an acquisition program, was developed for the regulation of defense acquisition program in the United States. Therefore, it is essential for us to figure out how we can adopt it under our defense acquisition regulations. We will give an alternative method to apply the PRICE model to the mapping problem between two regulations.

• Journal of the military operations research society of Korea
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• v.36 no.2
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• pp.71-84
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• 2010

This work describes capabilities based acquisition process in the SoS(System of Systems) environment. It is written as qualitative paper based on a cognitive paradigm. Future battle space is formed with grids of the various sensors and the shooters. It has been also transformed into a SoS concept which accomplishes missions and their functions through network based battle management systems in a single theater. The SoS is a set or arrangement of systems that results when independent and useful systems are integrated into a larger system that delivers unique capabilities. Therefore the acquisition process is changing over from single system requirements to capabilities based acquisition of the SoS. In this point of view, this paper analyzes functionally JCIDS, DAS and CEP which are critical elements of the acquisition process. From results of this comprehensive analysis, perspectives on the application of capabilities based acquisition suitable for Korean acquisition environment are presented.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.77-80
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• 2000

Adaptive filter based code acquisition scheme offers a fast acquisition with a low error probability. However, it has been studied only under a coherent environment. In this paper, the noncoherent adaptive code acquisition scheme employing a differential detection technique is proposed. For the proposed scheme, system probabilities and the mean acquisition time are analyzed numerically. Simulation results show that the proposed system outperforms over the conventional matched filter by 2-4 ㏈ under AWGN channel for 16 taps.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.492-500
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• 2014

The defense industry export of Korea has been steadily risen since 2006. It is attained $340million, the highest export amounts ever, in 2013. As the defense industry export increase, Defense Acquisition Program Administration (DAPA) built defense industry export and import management system to assist export and to protect defense technologies. In this paper, we study factors to activate the defense industry export and import management system using Technology Acceptance Model(TAM) in compulsive usage environment. The significance of this study is as follows: First, we prove the reliability and feasibility of measurement variables in defense industry of compulsive usage environment. Second, we suggest factors to activate the defense industry export and import management system. Third, we present methodology to find factors in computation systems of public institute using TAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.371-380
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• 2006

The performance characteristics of the cell averaging(CA), greatest of(GO), and smallest of(SO) constant false alarm rate(CFAR) processors in homogeneous environment are obtained and compared when receiving antenna diversity is employed in the pseudonoise code acquisition of direct-sequence code division multiple access (DS/CDMA) systems. From the simulation results, it is observed that the CA CFAR scheme has the best performance and the GO CFAR scheme has almost the same performance as the CA CFAR scheme in homogeneous environment. In Part 2 of this paper, the CA, GO, and SO CFAR processors for code acquisition in nonhomogeneous environment are addressed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.4
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• pp.176-181
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• 1997

A practical, easy-to-use data acquisition device has been developed for use in civil and envirionmental engineering applications. It uses the PC parallel port for the acquisition and data transfer and is simple enough to be setup and run in laboratory and field experiment conditions. The usual limitations of data storage capacity of several data loggers was solved by using PC resources. Also versatile programming capability using high level languages of the PC programming environment such as C and Visual Basic enables the data acquisition device to be configured as a general and practical data acquisition system. An example of effective uses of the device is. provided for the water environment measurement at the Bangwha bridge construction site. The in site. test proved the device to be practical in civil and environmental engineering applications.