• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.8
• /
• pp.1-7
• /
• 2004

The effect of the sub-optimal beam-forming and the fading channel correlation on the closed loop transmit antenna diversity(CTD) system is investigated in frequency flat Rayleigh fading channels. The fast channel fading prevents the perfect channel estimation at a mobile station, hence the imperfect weight is applied to the antenna branch of transmitter. The weight causes sub-optimalbeam-forming and aggravates the performance of CTD system. The fading correlation or a wireless channel also is one of the factors decreasing the diversity gain. A bit error rate expression for the CTD system is analytically derived as a function of the channel estimation error, the channel correlation coefficient the feedback delay, and fading index. It is shown that the channel estimation error gives more severe effect to the system performance than the channel correlation.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.2
• /
• pp.72-78
• /
• 2001

The bead is used to provide properly restraining force in the sheet metal forming process. This bead process includes bending and geometrical non-linearity, and affects the state of binderwrap. Therefore, the analysis of bead process is very important to obtain the desired formability. In this paper, the research about the influence of the punch stroke of bead on the draw-bead process was conducted. Results from the analysis will give useful information to the effective tool design of blank forming process. To analyze the bead process, and elasto-plastic finite element formulation is constructed from the equilibrium equation and the considered boundary conditions involved a proper contact condition. The static-explicit finite element method as a numerical method for the analysis was applied to the analysis program code. It was found that this method could solve too much computation time and convergence problem owing to high non-linearity of bead forming process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.122-125
• /
• 2005

The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its saving time effectiveness. However, it's well known that the membrane analysis can not provides correct information for the processes which considerable bending effects. From this time research it tried to compare the formation analysis result which uses the shell element which is applied newly in the AutoForm and actual products. The shell element is compromise method between continuum analysis and membrane analysis. The Finite element method by using shell element is the most economical numerical method. From analysis results, FEA by using shell element can estimate accurately the problems happened in actual auto-body panel.

• International Journal of Computer Science & Network Security
• /
• v.24 no.4
• /
• pp.206-210
• /
• 2024

Industrial facilities that use modern IT technologies require the ensured reliability and security of information in automated enterprise management. Concurrently, so as to ensure a high quality of communication, it is necessary to expand the bandwidth of communication channels, which are limited by the physical parameters of the radio frequency spectrum. In order to overcome this contradiction, we propose the application of technology fundamental to ultra-wideband signals, in which the ratio between the bandwidth and its central part is greater than "one". For this reason, the information signal is emitted without a carrier frequency - simultaneously within the entire frequency band - provided that the signal level is lower than the noise level. For the transmission of information content, the method of positional-time coding is used, in which each information bit is encoded by hundreds of ultrashort pulses that arrive within a certain sequence. Mathematical models of signals and values observed in wireless communication systems with autocorrelation reception of modulated ultra-wideband signals are furthermore recommended. These assist in identifying features of the dependence of the error probability on the normalized signal-to-noise ratio and the signal base. Comparative analysis has shown that the best noise immunity of the systems considered in this paper is the communication system, which uses the time separation of the reference and information signals. During the first half of the bit interval, the switch closes the output of the transmitter directly to the generator of the ultra-wideband signal - forming a reference signal. In the middle of the bit interval, the switch alternates the output to one of two possible positions depending on the encoding signal - "zero" or "one", forming the information part of the ultra-wideband signal. It should also be noted that systems with autocorrelation reception and separate transmission of reference and information signals, provide a high level of structural signal secrecy. Furthermore, they provide the reliable transmission of digital information, especially in interference conditions.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.1069-1072
• /
• 1987

In this paper, we drive useful data from 3-D depth information as input using discontinuity boundary or clustering. And using magnitude and direction of z-gradient we classify the data into adaptable primitive types through intrinsic and stochastical processing. After these processing information is reconstructed for forming data base. And make relationship and standard view position for matching.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.61-64
• /
• 2003

The information display industry this century has to improve our life without increasing energy consumption. Suftla technology together with high-performance silicon thin film transistors (TFTs) and ink-jet technology for forming metal-wiring and organic TFTs will play leading roles for achieving this requirement. In this paper these technologies are reviewed and the concept of the information displays in near future is discussed.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.337-338
• /
• 2019

본 연구에서는 열자격전류의 측정을 통해 얻은 데이터를 유한요소법을 이용하여 일렉트렛트 형성에 깊은 관련이 있는 대전 과정에 관한 시뮬레이션을 수행하였는데, 전극의 에지효과로 인한 전계의 집중 현상을 확인하였고 일렉트렛트의 불균일한 대전 상태 여부를 검증한 후 최적 설계를 도출하여 각종 센서재료의 적용에 기여할 것으로 사료된다.

• Journal of Environmental Health Sciences
• /
• v.32 no.4 s.91
• /
• pp.353-358
• /
• 2006

This study was performed to evaluate the effects of input ratios of bulking material in aerobic composting of food wastes on variation of colony forming units of heterotrophic bacteria. Wood chips were used as a bulking material. Volume ratios of food wastes to wood chips in reactor of Control, WC-1 and WC-2 were 10/0, 10/5 and 10/10, respectively. Reactors were operated for 24 days with 1hour stirring by 1rpm and 2 hours of the forced aeration per day. WC-2 reached high temperature range faster than WC-1, and the maximum temperature of WC-2 was higher than that of WC-1. This means that the reaction velocity of composting of WC-2 was faster than that of WC-1. Judging from the profile of pH changes, composting of WC-1 proceeded slowly and continuously. Composting of WC-2 proceeded rapidly in the former half reaction period, and kept steady state of high pH in the latter half reaction period. Namely, composting of WC-2 was nearly completed in the former half reaction period. In the case of WC-1 and WC-2. the maximum temperature was followed by the rapid pH increase in 2-3 days, and this was followed by the maximum Colony Forming Units(CFU) in 3 days. But, these three items of WC-2 always appeared faster and higher than those of WC-1.

• The Journal of the Korea Contents Association
• /
• v.12 no.8
• /
• pp.178-186
• /
• 2012

This study examined the concept-forming process of Design-Art and based on it, drew the significance of Design-Art. Design-Art is generated by the policy cultivating star artists and star designers so as to pioneer new art-market in 1990s in the foundation of anti-area formed by Postmodernism in 1960s. It started to be vitalized while designers were born as author. At the same time, because of the information's popularity by internet's propagation, users started to manufacture and propagate contents volunteerly. Meanwhile, designers accepted artistic value so as to guarantee independent position, so the area of Design-Art became more strengthened. Therefore, Design-Art means 'design as an art' and Design-Artist obtained general meaning, 'designer as an author'. In 2000s, it secured variety because of the acceptance of existing art galleries' Design-Art works and forming of new Design-Art market such as Design-Art fair, and vitalization of the market played its own roles with the movement to create new-concept of design in design ecology. Based on the contents, this paper analyzed Design-Art works by Design-Artists working actively in actual field and examined the possibility of future development of Design-Art.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.8
• /
• pp.129-135
• /
• 2011

In this paper, we propose a multi target's elevation angle estimation method using multi beam forming technique. This method make a stacked beam to digital processing a received signal in array element. There can be desired receiving beam to application weight value at antenna element in beam forming. Currently, we are to make multi stacked beam using fast fourier transform in stead of phase shifter to be a computer performance much improvement. Also, we improve multi beam directivity using beam steering error correction technique in order to beam steering to desired direction in receiver. Through simulation, we show that the proposed elevation estimation method based on fast fourier transform and beam steering error correction technique, improves th performance of target estimation compared to previous method.