• Korea-Australia Rheology Journal
• /
• v.19 no.4
• /
• pp.233-242
• /
• 2007

We performed a numerical investigation to find out the optimal choice of the spatial discretization in the distributed-Lagrangian-multiplier/fictitious-domain (DLM/FD) method for the solid/fluid interaction problem. The elastic solid bar attached on the bottom in a pressure-driven channel flow of a Newtonian fluid was selected as a model problem. Our formulation is based on the scheme of Yu (2005) for the interaction between flexible bodies and fluid. A fixed regular rectangular discretization was applied for the description of solid and fluid domain by using the fictitious domain concept. The hydrodynamic interaction between solid and fluid was treated implicitly by the distributed Lagrangian multiplier method. Considering a simplified problem of the Stokes flow and the linearized elasticity, two numerical factors were investigated to clarify their effects and to find the optimum condition: the distribution of Lagrangian multipliers and the solid/fluid interfacial condition. The robustness of this method was verified through the mesh convergence and a pseudo-time step test. We found that the fluid stress in a fictitious solid domain can be neglected and that the Lagrangian multipliers are better to be applied on the entire solid domain. These results will be used to extend our study to systems of elastic particle in the Stokes flow, and of particles in the viscoelastic fluid.

• Archives of design research
• /
• v.16 no.2
• /
• pp.345-354
• /
• 2003

Digital TV broadcasting technology is recognized as a very encouraging technological development by koreans because of high-definition, multi-channel and interactive services which would broaden the viewers choice and promote people's prosperity. The technological development of digital TV service is a drastic change for people's convenience and would be a major media of‘e-government’in Korea. Digital TV Program UI will affect to people's esthetic sense and information efficiency. The information search pattern in TV is different from it of computer which has lead interactive media so far This research verifies the reasonable information display method through the usability test based on former related researches. For the case study, Interactive EPG design of SkyLife is selected and reviewed. This research includes the design development of interactive EPG of DVB-MHP.

• Journal of Distribution Research
• /
• v.12 no.4
• /
• pp.27-47
• /
• 2007

Using survey data and the Heckit model that adequately controls the sample selection bias, we analyze shoppers expenditure through two major emerging shopping channels: Internet shopping and TV home shopping channels. Age, Internet experience, daily Internet usage, the number of computers are factors that affect the ratio of consumers' expenditure through Internet shopping relative to the expenditure through TV home shopping. Shopping frequency which represents the shoppers' incentives to reduce transaction costs also has a positive effect on the proportion of shoppers' expenditure through the Internet shopping. Shoppers' perceptions of convenience, reliability, speed, and diversity are also shown to affect shoppers' relative expenditure ratio through Internet shopping. In contrast, shoppers' perception of prices does not seem to affect their purchasing behavior.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.2
• /
• pp.243-251
• /
• 2010

The military has been putting great efforts into applying data communication on existing voice communication systems being used in NCW(Network Centric Warfare). Data communication will be an effective choice in one of many effort to yield a minimum kill chain, comparing to legacy voice communications, when tactical units conduct their missions. However, the required budget will be enormous, in case of the replacement of a lot of legacy communication systems with new one. As a cost-effective alternative, the tactical data communication systems using the conventional radio systems instead of the development of new radio systems has been proposed. It is mandatory, though, to ensure QoS while maintaining data communication by making use of legacy radio systems already in use. This paper focuses on the performance issues experimented and analyzed for tactical data communication through the legacy radio systems as the first step towards guaranteed QoS. We have conducted various experiments such as the transmission error rate on certain tactical messages, performance evaluation of redundant transfers, the relationship between the transmission frame size and rate of error, the identification of error points in the transmission frame, and techniques to reduce the errors in both hopping and non-hopping modes. As a result of the performance experiments, The adaptive communication module which decides the redundant transmission or the Forward Error Correction(FEC) technique by analyzing channel status and current transmission status(hopping/non-hopping) of the legacy radio should be designed. the FEC technique in non-hopping, and the redundant transmission technique in hopping mode was recommended from the result of experiment with the frame size is 20bytes in non-hopping and 10Bytes frame size in hopping mode.

• The Journal of the Korea Contents Association
• /
• v.11 no.10
• /
• pp.128-136
• /
• 2011

This is a study on the subjectivity of audiences about preference of documentaries on TV. Accordingly, Q-methodology was used for this study. As a result, audiences' various characteristics by preference types were able to be found. The individual characteristics were classified into three styles: an entertainment-oriented style pursuing enjoyment, public and society interest-oriented style pursuing public purpose, and culture-oriented style pursuing artistic value of documentaries in order. It could be inferred from the classification of preference styles that unlike the past, the choice of TV broadcasting of audiences was shifting from the passive and media-dependent form to positive form. Therefore, the research and development of content delivery and production in the multi-media and multi-channel digital broadcasting era should be focused on not only the content itself but also an audience-centered service development model reflecting audiences' desire and hope.

• Food Science of Animal Resources
• /
• v.25 no.3
• /
• pp.271-276
• /
• 2005

A totally 178 housewives in Gyeongnam were surveyed on consumer's purchase behavior and perception of branded pork. The degree of consumers' perception and reliance on the branded pork was still low. Consumers' consideration quality factors when buying pent is higher in order of safety/hygiene>taste/tenderness>meat color, In taste, consumer preferred Korean native pig meat when compared to the common meat. But the consumers have a notion that the price of Korean native pig meat was too expensive. The consumer preferred consumer group to government agency as a official approval organ for pork quality assurance. The consumers had different behavior in information channel, purchase frequency and place depending on age, income. In the development of branded pork, further studied are required on consumers' purchase behavior, perception, preference choice and decision-making process of branded pork.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.106-106
• /
• 2011

Recently, zinc oxide (ZnO) thin films have attracted great attention as a promising candidate for various electronic applications such as transparent electrodes, thin film transistors, and optoelectronic devices. ZnO thin films have a wide band gap energy of 3.37 eV and transparency in visible region. Moreover, ZnO thin films can be deposited in a poly-crystalline form even at room temperature, extending the choice of substrates including even plastics. Therefore, it is possible to realize thin film transistors by using ZnO thin films as the active channel layer. In this work, we investigated influence of oxygen partial pressure on ZnO thin films and fabricated ZnO-based thin film transistors. ZnO thin films were deposited on glass substrates by using a pulsed laser deposition technique in various oxygen partial pressures from 20 to 100 mTorr at room temperature. X-ray diffraction (XRD), transmission line method (TLM), and UV-Vis spectroscopy were employed to study the structural, electrical, and optical properties of the ZnO thin films. As a result, 80 mTorr was optimal condition for active layer of thin film transistors, since the active layer of thin film transistors needs high resistivity to achieve low off-current and high on-off ratio. The fabricated ZnO-based thin film transistors operated in the enhancement mode with high field effect mobility and low threshold voltage.

• Korean Journal of Optics and Photonics
• /
• v.16 no.3
• /
• pp.266-274
• /
• 2005

We have designed photonic crystal based bandpass filters whose characteristics are suitable for WDM communication system. The filters consist of coupled point defect resonators in two-dimensional photonic crystal. The frequency response of coupled resonators has been analyzed by the coupling of modes in time, from which the design parameters for the coupled resonator filters have been extracted. For the appropriate choice of the design parameters, each resonator is treated as a lumped L-C resonance circuit, and from the analogy between the equivalent circuit and the standard L-C filter circuits, the design parameters are simply determined from the table for general filter circuit design. Based on the determined design parameters, a photonic crystal based filter has been designed and its performance has been calculated using the finite-difference time-domain method. The designed filter shows a pass band of 50GHz and 0.5 dB in-band ripple, which is suitable for typical WDM communication systems with 100GHz channel spacing.

• Journal of Communications and Networks
• /
• v.18 no.3
• /
• pp.364-374
• /
• 2016

With vast amounts of spectrum available in the millimeter wave (mmWave) band, small cells at mmWave frequencies densely deployed underlying the conventional homogeneous macrocell network have gained considerable interest from academia, industry, and standards bodies. Due to high propagation loss at higher frequencies, mmWave communications are inherently directional, and concurrent transmissions (spatial reuse) under low inter-link interference can be enabled to significantly improve network capacity. On the other hand, mmWave links are easily blocked by obstacles such as human body and furniture. In this paper, we develop a multi-hop relaying transmission (MHRT) scheme to steer blocked flows around obstacles by establishing multi-hop relay paths. In MHRT, a relay path selection algorithm is proposed to establish relay paths for blocked flows for better use of concurrent transmissions. After relay path selection, we use a multi-hop transmission scheduling algorithm to compute near-optimal schedules by fully exploiting the spatial reuse. Through extensive simulations under various traffic patterns and channel conditions, we demonstrate MHRT achieves superior performance in terms of network throughput and connection robustness compared with other existing protocols, especially under serious blockage conditions. The performance ofMHRT with different hop limitations is also simulated and analyzed for a better choice of the maximum hop number in practice.

• Archives of design research
• /
• v.12 no.4
• /
• pp.201-209
• /
• 1999

Feb. 11. 1997, Korean Government announced FM Radio Broadcasting and TV Terrestrial TV Broadcasting will be changed to digital format in year 2001, and all Korean Broadcasting except AM Radio and Microwave will be changed to digital format before 2010. In spite of IMF economic crisis, the Digitizing is the one of the hot issue in TV Broadcasting area. The narrow view of the Digitizing the Broadcasting is a technical development from the analogue to digital, but the extended view of it means not only the technical development but the revolution in the concept of TV and service area, relationship between sender and receiver, structure of TV Industry. Thus Digitizing the Broadcasting shifts paradigm and eventually it cause a big change in the advertising creative. The digital TV could be a very encouraging technical development for the consumers convenience because of the multiple choice in the channels and interactive services which leads us to the multimedia service through the TV . On the other hand, multimedia and multi-channel, interactivity implicate a big uncertainty and risk, This research paper is about the technical aspects and social aspects of digital TV and its influence of the marketing and TV advertising creative.