• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.183-188
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• 2003

The $4^{th}$ generation mobile communications, through several radio access networks such as WLAN, Bluetooth, UMTS, GPRS, CDMA 1X, and IMT-2000 in the same area offering different type of coverage, will support interactive multimedia services in additions to wider bandwidths, higher bit rates, and service portability. Regardless of various radio access networks, they will also support robust security mechanisms, as well as seamless mobility and common authentication. In this paper, we give an overview of WLAN security and examine its security problems. We also explain the enhanced security schemes, such as port-based authentication, EAP, and IEEE 802.1X. For secure wireless communications, several possible security solutions are offered and evaluated in various respects to improve WLAN security. This paper will make a contribution to provide more secure wireless communications to cellular operators embracing WLAN technology as a means to generate new revenues based on data services.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.807-814
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• 2004

Land seismic reflection survey has been increasingly demanded in various civil engineering works because of its own ability to delineate layers, water table, to detect cavities or fracture zones, to estimate seismic velocities of each layer. However, our shallow subsurface structures are very complex. The relatively thin layer(mostly soil) to the wavelength directly followed by a basic rock with high impedance used to generate complicated surface waves, kind of channel waves with high amplitude that is dominate in entire seismograms and hence the useful reflection events will be almost hopelessly immersed in the undesired surface waves. Thus, it would seem that the use of traditional seismic survey could not be likely to provide in itself a satisfactory information about our exploration targets. This paper hence introduces an efficient measuring strategy illustrating a properly controlled arrangement of the vertical single force sources commonly used, yielding a very sharply elongated form of P-energy with a minimum of S radiation energy, what we call, P-beam source. Abundant experiments of physical modeling showed that in that way the surface waves could be enormously reduced and the reflection events would be additive and thus reinforced. Examples of field data are also illustrated. The contribution of P-beam source will be great in civil engineering area as well as in general geological exploration area.

• Proceedings of the KIEE Conference
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• summer
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• pp.597-601
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• 2004

HVDC(High Voltage Direct Current) is an underwater cable between Jeju Island and Haenam in main land and supplies approximately $50\%$ of electrical usage in Jeju Island. If there is any power failure due to HVDC, it will cost approximately 50,000 US dollars per day including Thermal Electrical Generation. Therefore it is absolutely necessary to recover the problem in rapid timely basis. Present survey method in Korea is done by scuba diver with air cylinder resulting very poor visual inspection. Other option is by only visual camera attached on miniature ROV for solely suey Purpose. This method does not includeburial depth of cable, cable position, cable condition & etc??‥‥.??? In result, current method does not generate any scientific or sophisticated data which does not allow any intelligent management decision. In conclusion, new method and new systems are needed urgently to upgrade current HVDC underwater cable survey technique in Korea to minimize the cost and time factors.

• Korea Journal of Hospital Management
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• v.8 no.1
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• pp.42-63
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• 2003

There is a rapidly growing expansion of internet-based infrastructure throughout industries in Korea. The internet-based Electronic Purchase and Supply System(EPSS) is being considered a supportive tool to increase the economic efficiency of hospital management. In this study, we conducted an economic evaluation of the system, analyzing data on four hospitals in Korea. According to the results, four hospitals was estimated to make net benefit of about 611 million Won in one year and about 2,809 million Won in the next five years. Further, the adoption of all hospitals in Korea to the system may generate net benefit of about 31,575 million Won in one year and about 166,938 million Won in the next five years. Furthermore, we expect that as the system covered many kinds of inputs in hospitals like pharmaceuticals, the benefit of the system would go up by a considerable degree.

• Journal of Families and Better Life
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• v.26 no.5
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• pp.61-74
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• 2008

This research aims to examine and analyze behavior of consumers in pursuit of safety the basis of data Korea Consumer Agency in 2007 2,000 male and females older than 20 years old in Korea. In particular, this study investigates the impact of and life styles of consumers in pursuit of safety. Results of this research could be summarized as follows. First of all, Korean consumers tend to place emphasis on factors such as price and freshness rather than safety in the purchase of vegetables, meats, rice, and fruit.Second, the safety consciousness of consumers is high among female young consumers among consumers showing intermediate positions for the issue of opening domestic markets for foreign agricultural products. Third, this study also examines the impact of life styles on consumers' behavior in pursuit of safety. Such behavior is high among consumers emphasizing values on family and current consumption and showing negative attitudes opening domestic markets for imported foreign agricultural products. Finally, behavior in pursuit of safety is high among female, high school graduated, family-oriented consumers and valuing leisure and showing negative attitudes opening domestic markets for foreign agricultural products. However, safety consciousness of consumers do not generate direct impact on patterns of pursuing safety.

• Journal of the Korea Computer Graphics Society
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• v.4 no.2
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• pp.1-13
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• 1998

The most important goal of character animation is to efficiently control the motions of a character. Until now, many techniques have been proposed for human gait animation, and some techniques have been created to control the emotions in gaits such as "tired walking" and "brisk walking" by using parameter interpolation or motion data mapping. This paper proposes a human running model based on a one-legged hopper with a self-balancing mechanism. The proposed technique exploits genetic programming to optimize movement, and can be easily adopted to various character models. We extend the energy minimization technique to generate various motions in accordance with emotional specification.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.89-90
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• 2008

We present an implementation and it's real-sea test of an underwater acoustic communication system, which allows the system to reduce complexity and increase robustness in time variant underwater environments. For easy adaptation to complicated and time-varying environments of the ocean, all-digital transmitter and receiver systems were implemented. For frame synchronization the CAZAC sequence was used, and QPSK modulation/demodulation method with carrier frequency of 25kHz and a bandwidth of 5kHz were applied to generate 10kbps transmission rate including overhead. To improve transmission quality, we used several techniques and algorithms such as adaptive beamforming, adaptive equalizer, and convolution coding/Viterbi decoding. For the verification of the system performance, measurement of BER has been done in a very shallow water with depth of 20m at JangMok, Geoje. During the experiment, image data were successfully transmitted up to about 9.6km.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.971-976
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• 2014

Haptic device can be a useful rehabilitation tool in balance training. The proposed system is composed of a body-wear smartphone, Phantom Omni(R) device, and its control PC system. Ten young healthy subjects performed balance tasks with different postures during 30 seconds with their eyes closed. An Android program on the smartphone transferred mediolateral (ML) and anteroposterior (AP) tilt angles to the PC system, which can generate haptic command through haptic device. Statistical data analysis was performed using MATLAB(R). COP (Center of Pressure) related indexes were measured to see reduction in body sway. ANOVA showed that haptic device significantly reduced body sway. Intuitive balance guidance could be generated using an economical and small-sized commercial haptic device, making the system efficient.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.2 s.332
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• pp.49-56
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• 2005

In this paper, we propose a memory BIST Circuit Creation System which creates BIST circuit based on user defined fault model and generates the optimized march test algorithm. Traditional tools have some limit that regenerates BIST circuit after changing the memory type or test algorithm. However, this proposed creation system can automatically generate memory BIST circuit which is suitable in the various memory type and apply algorithm which is required by user. And it gets more efficient through optimizing algorithms for fault models which is selected randomly according to proposed nile. In addition, it support various address width and data and consider interface of IEEE 1149.1 circuit.

• ETRI Journal
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• v.20 no.1
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• pp.55-73
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• 1998

In this paper we analyze the technological accumulation processes in the Korean semiconductor industry from the institutional approach. Institutional approach, which is closely connected with Neo-Schumpeterian tradition, has emerged as an alternative theoretical framework to neoclassical approach to understand the process of producing technological knowledge. Traditional wisdom of neoclassical approach revealed the limitation to explain the complex nature of knowledge creation and diffusion. US patent data are analyzed in terms of the increasing trend of numbers and its content to measure the rate and direction of technological capability accumulation. This analysis shows that semiconductor technologies are one of the fastest growing fields among Korean technological activities. Moreover, the analysis of patent content suggests that fabrication technologies are the most important area within the technological development of semiconductors, whilst circuit design and testing technologies are beginning to increase in significance. In addition, it is examined how private sectors and public institutions have contributed to generate technological capabilities, and the relationship between them has been changed during the development processes. It is found that Korean firms enhanced their technological capabilities from the learning and assimilation of imported technology to enhanced in-house R&D capabilities in the later stage. The support of public institution and government policy also played significant role to this successful transformation in conjunction with vigorous R&D investment of public sector.