• Journal of Communications and Networks
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• v.4 no.4
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• pp.344-350
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• 2002

This work summarizes the current state of the art in software radio for 4G systems. Specifically, this work demonstrates that classic radio structures, e.g., heterodyne reception, homodyne reception, and their improved implementations, are inadequate selections for multi-mode reception. This opens the door to software defined radio, a novel reception architecture which promises ease in multi-band, multi-protocol design. The work presents the many advantages of such an architecture, including flexibility, reduced cost via component reduction, and improved reliability via, e.g., the elimination of environmental instability. The work also explains the limitations that currently curtail the widespread use of SDR, including issues surrounding A/D converters, management of software and power, and clock generation. This provides direction for future research to enable the broad applicability of SDR in 4G cellular and beyond.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.485-487
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• 2000

Dielectric strength of insulators made of epoxy composites rapidly decreases due to ageing to interfaces between the matrix resin and filler particles. The adhesion variation of interfaces caused by moisture absorption also alters electrical properties that are the basic characteristics of insulators, particularly, in out door use. In this paper, electrical properties of epoxy/$SiO_2$ composites were investigated at boiling absorption condition to observe that influence of moisture. The breakdown time of samples were measured under AC 6[kV] applied voltage, and the variation of lifetime was varified by using Weibull distribution function.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2349-2351
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• 1999

In this paper, the variable absorption rates and DC dielectric breakdown strength of epoxy composites were measured at boiling absorption condition in order to observe the influences of moisture in out door use. Also, in order to improve withstand voltage properties at moisture absorbtion condition. IPN (interpenetrating polymer network) method which had been already reported, was introduced and the influence was investigated. As a result, it was confirmed that the moisture absorption rate was increased and DC dielectric breakdown strength was degraded with boiling time and filler content increasing. On the other hand, it was confirmed that moisture absorption rate and DC dielectric breakdown strength degrading rate were lowered by the improvement of adhesion strength In IPN specimens.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.259-266
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• 1999

This paper is intended to provide a method to design control software for the TCMS, train control and monitoring system. The TCMS with this control software will be applied KOREA Standard EMU. The control software is designed by SCADE Case tool to concern safety and reliability. The function for the EMU is implemented in software easily programmed, using a functional block, graphic programming language. The control software has modular design and each module is tested with SCADE simulator. This time we focus a door control module, present a design method and a simulation method for that module.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1385-1395
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• 2008

The introduction of KTX(Korea Train Express) has brought an historic change to the overall transit system in Korea. Especially, the high-speed railway stations are expanding the scope as public transit centers. However, we cannot deny that the evaluation on the high-speed railway stations had not been performed successfully so far. The evaluation covers from the connectivity of the scope from door to the stations and the transfer service in the interior of stations. We developed the service evaluation indicators of transfer facilities in the high-speed railway stations. The indicators consist of level of service(LOS), the propriety of allocation, and the quality of information throughout the facilities in the centers. We examined the 7 stations in Korea and standardized the methodology of the evaluation process by applying the indicators. Also, the evaluation is performed easy for anyone to follow.

• Elastomers and Composites
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• v.51 no.1
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• pp.38-42
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• 2016

For improving the heat loss of a refrigerator around door gasket, it is very important to reduce the amount of rubber magnet used, of which thermal conductivity is much higher than the plastics, and enhancing the magnetic properties of rubber magnet itself is crucial for this. In the present study, therefore, a relationship between the optimum conditions of rubber magnet fabrication process and raw material compositions in the ferrite powder/CPE binder compounds was investigated for finding a way to enhance the magnetic properties of rubber magnet. Magnetic attraction forces of a sample rubber magnet was measured as function of distance, and thermal properties of the sample ferrite powder/CPE binder compound were analyzed with TG/DTA thermal analyzer. As a results, a rubber magnet strip with enhanced magnetic properties was expected to be fabricated, of which raw material compound was prepared by compounding with higher ferrite magnetic powder concentration.

• Transactions of Materials Processing
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• v.9 no.1
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• pp.3-9
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• 2000

The new FLD of the laser welded blank, which includes FLCs of welded zone and base metals, is introduced. For the forming limits of welded zone, the hemispherical dome punch tests were performed with various widths of asymmetric specimen. The FLC0 as well as the dome height at fracture associated with various specimen widths in the same and different thickness combinations were found to see the formability depending on thickness combinations. In order to show the application of the new FLD, the measured strains of squared cup drawing and simulated strains of door inner panel stamping were compared with those of FLCs. The successful prediction of fracture in the applications reveals that the forming limits of welded zone and base metals should be separately found for more accurate evaluation of the formability and workability of the laser welded blank.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.10-14
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• 2003

Since most of main noise sources of the railroad vehicle are transmitted to the passenger's ear through the vibration of the panel, the sound insulation performance of the panels should be high enough to protect the passenger's ear from the noisy environment. Specifically, the composite materials which are generally used for reducing the weight of the vehicle compartment have the low insulation performance, thus noise control actions should be taken appropriately by considering the insulation performance of the panels. In this study, the insulation performances of the inner/outer panels of the compartment are evaluated. In addition, the contribution of the insulation performance of aluminum door is estimated and compared to those of composite panels. The results can furnish an in-depth understanding of the insulation characteristics of the panel of railroad vehicle.

• International Journal of Internet, Broadcasting and Communication
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• v.6 no.1
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• pp.1-4
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• 2014

In this paper, an augmented refrigerator is proposed that presents information to increase the awareness of electric power consumption of a household fridge. The key idea is to reflect wasteful behavior on the feedback to a user, rather than mere amount of consumption or duration of opening a door of a fridge.

• Journal of Family Resource Management and Policy Review
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• v.6 no.1
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• pp.53-72
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• 2002

The purpose of the research is to investigate the amount of private education expenditures for on-line education and the factors which affect on-line education expenditures and its decreasing effect of private education expenditures. The results of this study can provide basic materials to found policy to decrease private education market and private education expenditures. The sample of this study was 484 parents who had an experience using on-line education for their children being in mainly constituted by classes of pre-school over and less than high school student. The results was as follows. First, education expenditures for on-line education are 64,900won and the English and the Mathematics as main reasons using on-line education were that it is available for 24 hours and cheaper than off-line education. The parents got information for on-line education by internet, mass media and their next-door neighbors. Second, the significant variables which affect on-line education expenditures and its decreasing effect of education expenditures were the children's school level and financial related factors.