• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1075-1081
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• 2008

In this paper, we propose a code acquisition algorithm using optical orthogonal code (OOC) for optical code division multiple access (CDMA) systems. Generally, a good code acquisition algorithm offers short mean acquisition time (MAT). The conventional multiple-shift (MS) algorithm consists of two stages and has shorter MAT than that of well-known serial-search (SS) algorithm. This paper proposes a novel code acquisition algorithm called enhanced multiple-shift (EMS) algorithm. By using multiple thresholds, the proposed EMS algorithm provides shorter MAT compared with that of the MS algorithm. The simulation results show that the EMS algorithm presents shorter MAT compared with the MS algorithm in both single-user and multi-user environments.

• Journal of Software Engineering Society
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• v.24 no.3
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• pp.91-99
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• 2011

The weapon system acquisition for national defense is too costly, risky and requires high quality result. Because of these characteristics of the weapon system acquisition, the modeling and simulation is a prerequisite process for enhancing the effectiveness and efficiency of weapon system acquisition. We call the process as SBA (Simulation Based Acquisition). However the modeling and simulation entails costs of model development, execution and analysis. Thus, the SBA's effectiveness analysis is needed. Especially, we developed 4 types of index which represent the effectiveness thoroughly and we applied them to various weapon systems' acquisition process. This work presents the necessity of SBA by showing the application of suggested effectiveness index in various defense weapon system acquisition cases.

• The Journal of Information Systems
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• v.28 no.2
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• pp.53-72
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• 2019

Purpose The purpose of this study is to examine the impact of tie strength in the network of industrial clustering on the knowledge acquisition, integration and innovation performance of small and medium sized enterprises. We test the positive relationship of weak tie and knowledge acquisition, strong tie and knowledge integration, and the interaction effect of two tie strengths on both processes of knowledge acquisition and integration. By identifying these relationships, we can better understand how to manage the attributes of social networks in terms of tie strength in order to improve the performance of innovation for the small and medium sized enterprises. Design/methodology/approach We collect 200 survey data from 2 industrial cluster respectively: Pankyo and Guroo. In Pankyo, the proportion of IT industry is the highest (35%) while the proportion of manufacturing is highest (35%) in Guroo. Pooling the data from two industrial cluster, we check the reliability and validity of our research model and test the hypotheses. Findings First, we find the positive relationship of weak tie and knowledge acquisition from both industrial clustering. Weak tie is composed of heterogeneous organizations with various background and expertise. The communication and information sharing of organizations in the weak tie network helps the idea generation for organization's innovation, which is the knowledge acquisition process. Second, the relationship of strong tie and knowledge integration is insignificant. Typically the strong tie from long-lasting partnership is expected to be beneficial in the action stage of innovation, which is the knowledge integration process. However it is not identified in our industry cluster. Finally, the interaction effect of weak and strong tie is identified to be effective on both knowledge acquisition and integration processes.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.113-119
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• 2021

Since the weapon system project has a large ripple effect on the country by investing a huge budget, analysis of acquisition methods that secured economic feasibility is required in the planning stage to promote the weapon acquisition project. In response to this demand, economic analysis for acquisition method is preformed in the research stage of previous studies, but the analysis on economic analysis for acquisition alternative is imperfect at the present. In this research, we identify the limitations of the effect analysis and propose an additional cost-benefit analysis method to analyze the economic feasibility of the acquisition alternative. It is possible to present the universal results of economic feasibility analysis for not only multiple alternatives but also single alternatives by presenting benefit/cost ratio. It is applied to research on acquisition project of OO guided rocket, and the result of economic analysis for each alternative is presented.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.33-38
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• 1989

This paper is about construction of Data Acquisition System for Gyro-System which obtains the information such as position, velocity, acceleration and attitude etc of Dynamic Vehicle System. We made up the Data Acquisition System using IBM-PC and in connection with CYBER 180-830 based on rate table, controller and IEEE 488 Interface etc.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.3-7
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• 2012

Purpose : In myocardial perfusion SPECT, the type of orbit (circular vs. body contouring) that affect the image quality is still on the debate. Presently in the nuclear medicine field, the body contouring orbit acquisition is widely used to improve the image quality on the myocardial perfusion SPECT. But in case of body contouring acquisition using the vertical method with dual detect machine, there is a tendency of increasing the radius. In this research, we compared body contouring orbit acquisition with circular orbit acquisition, so we suggest ideal method that reduces the radius for improving image quality. Materials and Methods : Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on equally with counts from patient's body. The study was performed under six different conditions. To compare image quality according to the radius, we increased radius sequentially per step during circular orbit acquisition. On the other hand, sensors that protect a collision and reduce the radius automatically were used to acquire image during body contouring orbit acquisition. So we compared FWHM value of apex. In clinical studies, we analyzed the 40 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center in August 2011. To acknowledge the differences according to the radius, we acquired the results two times using circular orbit acquisition and body contouring orbit acquisition. Results : In phantom study, we analyzed that increase of radius resulted in changes of FWHM value. It was 5.41, 6.24, 6.33, 6.42, 6.93 mm. On the other hand, using the body contouring orbit acquisition, FWHM value was 6.23 mm. In clinical study, difference of average radius between two methods was 2.5 cm (circular orbit acquisition was more close to patients). Conclusion : Through the experiments using Anthropomorphic torso phantom and patients data, we found that FWHM value of circular orbit acquisition was lower than body contouring orbit acquisition. As a result, if the difference of average radius exists approximately 3 cm, circular orbit type acquisition is better than body contouring type acquisition. But clinical investigation is only aimed to average radius, so it needs more investigation in comparison of patient's image.

• Lingua Humanitatis
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• v.7
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• pp.335-353
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• 2005

In recent years there has been much discussion about whether there is a critical, or sensitive period for language acquisition. Research on a critical period provides an excellent example around which we can organize a discussion of the behavioral and neural evidence. In this paper, the early history of critical periods and evidence for the existence of critical periods in various domains of human cognition and learning are reviewed. Followed by this overview, evidence for a critical period in both linguistic and non linguistic area are presented. The paper then provides some unresolved questions regarding a critical period in language acquisition and states what the outcome of this issues mean for an understanding of language acquisition. Finally the paper concludes with some educational implications of a critical period for practice.

• Journal of the Korean Society of Systems Engineering
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• v.8 no.1
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• pp.77-82
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• 2012

In Weapons acquisition process, if the requirements are not clear, it leads to confusion and conflict in business. In the development of next-generation weapons, to define and derive requirements has to start from decision of operational concept. It is difficult task and has many uncertainties. This paper has goal about development of knowledge acquisition process that derive military operational scenario-based requirements acquisition process and framework that classify and save the derived requirements for next project. That framework can generate new class and category, also suggest that verification of requirements. It help to derive and manage the requirements, and make it easy to grasp the requirements. Accordingly, it can help make military requirement plan and weapon acquisition process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.41-48
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• 2011

This paper proposes an efficient code acquisition scheme for direct-sequence spread spectrum (DSSS) based real-time locating systems (RTLS). The proposed scheme employs multiple bit integration to significantly decrease false alarms when no packet signal is transmitted and increase the detection probability when the RTLS tags are excited. The performance of the proposed code acquisition scheme is analyzed and numerically evaluated, and compared with those of single-dwell and traditional double-dwell code acquisition schemes. The simulation results show that the proposed multiple-bit integration scheme outperforms single-dwell and double-dwell schemes.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.538-540
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• 2004

Electrical currents generated by human heart activities create magnetic fields represented by MCG(MagnetoCardioGram). Since an MCG signal acquisition system requires precise and stable operation, the system adopts hundreds of SQUID(Superconducting QUantum Interface Device) sensors for signal acquisition. Such a system requires fast real-time data acquisition in a required sampling interval, i.e., 1 mili-second for each sensor. This paper presents designed hardware to acquire data from 256-channel analog signal with 1 ksamples/sec speed, using 12-bit 8-channel ADC devices, SPI interfaces, parallel interfaces, 8-bit microprocessors, and a DSP processor. We implemented SPI interface between ADCs and a microprocessor, parallel interfaces between microprocessors. Our result concludes that the data collection can be done in $168{\mu}sec$ time-interval for 256 SQUID sensors, which can be interpreted to 6 ksamples/sec speed.