• The Journal of Society for e-Business Studies
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• v.6 no.3
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• pp.1-16
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• 2001

In this paper, we introduced a POS(Point of Sale) system for a wallpaper company. We designed the database schema for the POS system, and proposed various application areas of the POS system. Especially, we discussed such application areas as inventory control, marketing, product development, and distribution channel. The quality of product management is enhanced by precise ABC inventory control and safety stock control. Marketing strategies can be more precisely established, and their effects can be measured. The development time can be shortened and new products can be developed based on the real market demands. Distributors can improve their management quality using precise sales data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.86-93
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• 2011

The necessity of Power Quality(PQ) Management grow bigger because the disturbance strength in power system is increasing, on the other hand, the tolerance of electrical components is reducing with widely use of the IT and digital equipments. The domestic management standards on power quality are enacted based on the IEC standards in recent. Since the IEC standards defines the measurement and evaluation point on PQ as PCC(Point of Common Coupling) which is normally the point of penetration between customer and power company, the PQ monitoring system(PQMS) should be made to measure and manage the PQ of custom effectively. In this paper, therefore, the economical construction plan on PQMS using the wireless communication channel in distribution automation system is suggested, and the usefulness of the PQMS are shown by analyzing the PQM data with IEC standards.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.597-602
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• 2000

In a MEMS(micro-electro mechanical system), the fluid may slip near the surface of a solid and have a discontinuous temperature profile. A numerical prediction in this slip flow region can provide a reasonable guide for the design and fabrication of micro devices. The compressible Navier-Stokes equation with Maxwell/smoluchowski boundary condition is solved for two simple systems; couette flow and pressure driven flow in a long channel. We found that the couette flow could be regarded as an incompressible system in low speed regions. For the pressure driven flow system, we observed nonlinear distribution of pressure in the long channel and numerical results showed a good agreement with the experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.641-648
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• 2002

The study on the chip waveform design to minimize multiple-access interference (MAI) and its performance evaluation are very important since chip waveform decides the signal quality and system capacity of the direct-sequence CDMA wireless communication system. This paper suggests the analytical chip waveform to minimize the MAI. The BER and throughput performances achieved by the proposed analytical optimum chip waveform are compared with those of the conventional chip waveforms in the Nakagami-m distribution frequency selective channel when the differential phase shift keying (DPSK) is employed in DS-CDMA system. From the numerical results, capacity and throughput are improved about 2 times and 1.4 times respectively when it is compared with the Kaiser chip waveform that is considered as one of the best in the conventional ones.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.111-116
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• 2010

In a large area magnetron sputtering system, which is under the influence of high heat load from the plasma, it is necessary to use the effective water cooling in order to maintain the proper deposition performance and the economic use of target materials. A series of three-dimensional numerical simulations are carried out on the simplified model of the large area magnetron sputtering system with the cooling plate that includes the U-shaped water channel. The analysis is focused on the effects of water channel geometry, cooling water flowrate, thermal conductivity of target material, and the degree of target erosion on the cooling performance of cooling plate, which is represented by the temperature distribution of target material.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1677-1688
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• 1998

In this paper, we analyze the performance of a DS-CDMA system employing adaptive adaptive array antenna technology at base-station. For the analysis the receiving architecture of a multiple team adaptive base-station array antenna is proposed as a major system omponent, and signal to interference and noise ratio(SINR) on the proposed architecture is developed. We show that the perfomance enhancement of the CDMA system is represented as great reduction of interfreence by employing an array antenna capable of resolving the angular distribution of the mobile users as seen at the ase-station. The energy associated with each mobile or a group of mobiles is thus confined within the addressed volume, greatly reducing the amount of co-channel interference experienced from and by neighboring co-channel cells. In order to ascertain the benefits of such an antenna, a theoretical approach, which eis based on the conventional and proposed antenna systems in a typical mobile radio environment, is adopted. Finally computer simulation results show the insight into how the adaptive array antenna operates when used in conjunction with DS-CDMA and illustrate the potential benefits in the SINR point of view.

• Journal of Agricultural Extension & Community Development
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• v.14 no.1
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• pp.171-195
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• 2007

Gyeonggi rice has been placed relatively favorable market position in the domestic rice market. With the superiority of its quality, gyeonggi rice has been well recognized to consumers. The price of gyeonggi rice has placed higher position than that of others. But, gyeonggi rice are facing crisis on the competition by regional brands. Therefore, this study was carried out to find the differentiated marketing strategies on problem related with the product differentiation and brand marketing of gyeonggi rice. In order to find out how much the effort on the product differentiation of gyeonggi rice affects the price and brand recognition, fifty RPCs in gyeonggi province were surveyed. As the results, $22{\sim}23%$ of harvested rice which was gathered into RPC was come out 'obscurity of production origin' when we consider material hull rice in the original production territory by collecting time and channel. With comparing sales weight of gyeonggi rice by the place of shipment, agricultural cooperative channel was the highest by 44.7%. And, wholesaler comes to 17.7%, discount outlet store was 13.9%, large quantity delivery in business was 11.1%, and department store was only 5.2%. Finally, we could consider to adopt the traceability system on gyeonggi rice distribution system from production to consumers' table to get consumers' credibility and compete imported high quality rice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1107-1119
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• 2006

Data transmission experiences multiplicative distortion in frequency nonselective fading channel. This distortion occurs in OFDM communication channel and can be compensated using an equalizer. Usually, in the case of LMS equalizer, eigenvalue distribution of training signal is enlarged. Large eigenvalue distribution causes principally the performance of a communication system to be deteriorated. This paper proposes a new algorithm that shows the same performance as the existing fast wavelet transform algorithm with less computational complexity. The proposed algorithm was applied to an adaptive equalizer of OFDM communication system. Matlab simulation results show a better performance than the existing one. The proposed algorithm was implemented in VHDL and simulated.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.941-950
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• 2001

A study of counter-current two-phase flow in narrow rectangular channels has been performed. Two-phase flow regimes were experimentally investigated in a 760mm long and 100mm wide test section with 2.0 and 5.0mm gap widths. The resulting flow regime maps were compared with the existing transition criteria. The experimental data and the transition criteria of the models showed relatively good agreement. However, the discrepancies between the experimental data and the model predictions of the flow regime transition become pronounced as the gap width increased. As the gap width increased the transition gas superficial velocities increased. The critical void fraction for the bubbly-to-slug transition was observed to be about 0.25. The two-phase distribution parameter for the slug flow was larger for the narrower channel. The uncertainties in the distribution parameter could lead to a disagreement in slug-to-churn transition between the experimental findings and the transition criteria. For the transition from churn to annular flow the effect of liquid superficial velocity was found to be insignificant.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.119-126
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• 2007

Because of the low temperature operation, proton exchange membrane (PEM) fuel cell has a water phase transition. Therefore, water management is an important operation issue in a PEM fuel cell because the liquid water in the fuel cell causes electrode flooding that can lower the cell performance under high current density conditions. In this study, in order to understand the reactant distributions in the cathode channels of the PEM fuel cell, an experimental technique that can measure the species concentrations of reactant gases by using gas chromatograph (GC) is applied for an operating PEM fuel cell. The oxygen distribution along the cathode flow channels of PEM fuel cell is mainly investigated with various operating conditions. Also, the relations between cathode flooding and oxygen concentrations and oxygen consumption pattern along the cathode channel configurations of the unit cell adopted for this study are discussed using GC measurement and visualization experiment of cathode flooding. It is found that the amount of oxygen consumption is very sensitive to various operating conditions of the fuel cell and was much affected by the flooding occurrence in cathode channels.