• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.489-491
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• 2002

The need for video diagnosis in medicine has been increased and real-time transfer of digital video will be an important component in PACS and telemedicine. But, Network environment has certain limitations that the required throughput can not satisfy quality of service (QoS). MPEG-4 ratified as a moving video standard by the ISO/IEC provides very efficient video coding covering the various ranges of low bit-rate in network environment. We implemented MPEG-4 CODEC (coder/decoder) and applied various compression ratios to moving ultrasound images. These images were displayed in random order on a client monitor passed through network. Radiologists determined subjective opinion scores for evaluating clinically acceptable image quality and then these were statistically processed in the t-Test method. Moreover the MPEG-4 decoded images were quantitatively analyzed by computing peak signal-to-noise ratio (PSNR) to objectively evaluate image quality. The bit-rate to maintain clinically acceptable image quality was up to 0.8Mbps. We successfully implemented the adaptive throughput or bit-rate relative to the image quality of ultrasound sequences used MPEG-4 that can be applied for diagnostic performance in real-time.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.278-287
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• 2011

NMEA 2000 protocol known as IEC 61162-3 of Multi-talker, Multi-listener and Plug and Play network communication has been adopted as standard network for SOLAS(Safety of Life at Sea) ship by IMO. This paper focuses on the implementation of FPGA and MicroBlaze for NMEA 2000 based gateway, which is able to convert NMEA 2000 protocol into various types of network protocol such as Ethernet, UART and USB using Vertex4-based ML401 board. Each communication module and the stack of NMEA 2000 are mounted on FPGA. To be able to receive each communication data, ML401 board is configured to handle required communication speed. PC based NMEA 2000 monitoring program is developed to verify that data on different networks are correctly converted each other in real time.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.226-228
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• 2008

In recent years, the companies of electric power equipment for MV and HV classes trend to develop the eco-friendly insulated(solid, eco-gas, air etc.) switchgear which replaces existent SF6 gas insulated switchgear due to environmental problems such as global warming and so on. This paper makes reference to the newly developed Solid Insulated Switchgear (SIS) which uses the eco-friendly material such as epoxy for insulation. The insulation of the solid insulated switchgear (SIS) is composed of an epoxy, vacuum and air. The solid insulated switchgear (SIS) is a slate of the art product. The advantages of SIS are advanced reliability, economical efficiency, safety, maintenance free, reduction of installation area and the protection of environment. The solid insulated switchgear (SIS) is FE Analyzed such as electromagnetic, mechanical, thermal and fluid in order to find the optimal design. Thens SIS has been verified by international standard test. (IEC 62271 - 100 and so on.) As a result of this, the solid insulated switchgear (SIS) has been estimated as an alternative for eco-friendly MV class switchgear.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.610-622
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• 2003

Metadata Registry was developed to dynamically manage metadata and to increase interoperability between various and heterogeneous metadata. The built metadata registry can be used as a standard guideline for creation of new databases and it provides a radical data integration mechanism. However, in the situation that an enormous databases must be integrated progressively, there is a limit to the existing metadata-based approach. In case that each database has no statistical information for its use rate and the restricted cost is given to us for a unit time, existing metadata-based approaches do not provide how to select some databases to be preferentially integrated and to build a metadata registry progressively, In this paper, we propose a methodology that can create progressively metadata registries in the case. The proposed methodology is based on data visibility and hierarchical metadata registry. We also describe the system that have been developed for applying the methodology to a real domain, and then described its results.

• Journal of Internet Computing and Services
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• v.21 no.5
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• pp.39-48
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• 2020

Recently, the study and development of environment-friendly energy technique have increased in worldwide due to environmental pollution and energy resources problems. In vehicle industry, the development of electric vehicle(EV) is now on progress, and also, many other governments support the study and development and make an effort for EV to become widely available. In addition, though they strive to construct the EV infra such as a charge station for EV, the techniques related to managing charge demand and peak power are not enough. The standard of EV communication has been already established as ISO/IEC 15118, however, most of implemented EVs and EV charge stations do not support any communication between each of them. In this paper, an improved slow charge scheme for non-communication EVs is proposed and designed by using predicting charge demand. The proposed scheme consists of distributed charge model and charge demand prediction. The distributed charge model is designed to manage to distribute charge power depending on available charge power and charge demand. The charge demand prediction is designed to be used in the distributed charge model. The proposed scheme is based on the collected data which were from EV slow charge station in business building during the past 1 year. The system-level simulation results show that the waiting time of EV and the charge fee of the proposed scheme are better than those of the conventional scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1526-1537
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• 1998

The split-screen function on the multipoint control unit(MCU) which is usually using processing method based on pixel domain has many problems for manipulating the video signal in real-time. Although the researches and the developements to cope ith such problems are processing, these have too complex architecture to implement and are limited to method for H.261 video signal. In this paper, we propose a new mechanism for split-screen that can actually apply to ISO/IEC MPEG video standard. The new method that is proposed in this paper do the processes in complete compression domain, thus it is suitable for the application of real-time multipoint multimedia communication service. By simple interpreting and manipulating the MPEG video element stream, the split-screen functional module can be implemented easily and the result of the procedures does not accompany image degradation at all. Finally, the complexity of implementation, the aspect for processing delay and the loss of image quality as compared to that resulting in the case of applying the previous split-screen method has been investigated. And it is confirmed that the proposed mechanism has a significant advantage as a split-screen method.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.181-187
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• 2016

Typical Retro-reflectors installed on road have problems such as limiting a driver's visibility at night when it is foggy or rainy. On the other hand, LED illuminated studs, called cat's eye system, extends a driver's visibility under these conditions. In this paper, we present a design of the LED cat's eye system using solar energy that can sustain vehicles with about 30-ton weight and is compliant with the IP68 code for water proof as IEC standard 60529. In addition, we propose a scheme of designing a LED driving circuit consuming low power to take into accounts cold weather or rainy season with limited sunlight. This LED cat's eye studs is currently installed and used on expressway and bike route nationally as well as overseas.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.313-318
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• 2006

This paper introduces a partial discharge (PD) severity metric, S, based on the evaluation of time-sequence PD data capture and resulting Time-Sequence-Analysis Discharge (TSAD) level distributions. Basically based on an IEC60270 measurement technique, each PD event is time stamped and the discharge level noted. By evaluating the time differences between a previous and subsequent discharge, a 3D plot of time-sequence activity and discharge levels can be produced. From these parameters a measurement of severity, which takes into account dynamic or instantaneous variations in both the time of occurrence and the level of discharge, rather than using standard repetition rate techniques, can be formulated. The idea is to provide a measure of the severity of PD activity for potentially measuring the state of insulation within an item of plant. This severity measure is evaluated for a simple point-plane geometry in $SF_{6}$ as a function of gap distance and applied high voltage. The results show that as the partial discharge activity increases, the severity measure also increases. The importance of future investigations, quantifications and evaluations of the robustness, sensitivity and importance of such a severity measurement, as well as comparing it with typical repetition rate assessment techniques, and other monitoring techniques, are also very briefly discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.83-89
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• 2013

In order to reduce the power consumption in international standard IEC62087, the luminance efficiency should be improved at the low discharge load rather than at the high discharge load. Thus, this paper analysed the characteristics of the discharge at the panels with ITO Gap of $65{\mu}m$, $80{\mu}m$, and $100{\mu}m$ in 50-inch PDP with FHD resolution. It was well known that the long gap panel improves the luminance and the luminous efficiency. However, it is very difficult to drive the panel due to high driving voltage. When the normal driving method was applied at the panel with ITO gap of $100{\mu}m$, the phenomenon of the double peak was generated in the sustain period. We confirmed that main factor of the double peak is the self-erasing discharge. When the CLHS driving method was applied at the panel with ITO gap of $100{\mu}m$, the self-erasing discharge was improved in the sustain period. Also, the $V_S$ and $V_A$ minimum voltage of the CLHS driving method decreased about 9V and 12V compared with those of the normal driving method. Moreover, when the CLHS driving method was applied to the panel with ITO gap of $100{\mu}m$, the luminance and the luminous efficiency increased compared with those of the normal driving method. The luminance and the luminous efficiency greatly increased at the low discharge load. The less discharge load, the higher increase rate of the luminance and the luminous efficiency. Especially, the luminous efficiency at ITO gap of $100{\mu}m$ increased about 26.3% at the discharge load of 4% compared with that at ITO gap of $65{\mu}m$.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.122-124
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• 2003

In recent, the various electric & electronic machines are newly developed everyday and the electricity supply system & environment on the process from generation to consumption of electricity also is being changed. In other words, both supplier and consumer of electricity are required to be responsible for their interruption costs. So, it is very important and meaningful work for evaluating the interruption costs in quantitative. Additionally, since the restructuring of electric industry is on going in world wide, after restructuring, most of all electric utilities and consumer have to consider the supply reliability and quality as a important element of the calculating the related costs and contract because it takes costs to keep the supply reliability and quality highly. Especially, the interruption or the supply reliability will have influence on the bilateral contract between supplier and customer as a key point to determine the once in competitive electric market. Therefore, it has very important moaning to calculate the interruption costs in the present that it is prepared to open the competitive electric market. In this paper, international standards, i.e. IEC, IEEE, are applied to the analysis on the interruption costs used in the questionnaires which are newly designed including short duration interruption by the authors instead of traditional interruption criteria. Firstly, using the questionnaires, the authors got related data from industries according to the standard industry classification which are being used in electric utility and other national statistics in Korea. However, analysis results are hard to say typical value because of the not so many samples. So, the authors are going to survey and focus on not all kinds of industry but a few kinds of them that their facilities are effected or stop by short duration interruptions, so there are large economical damages. Finally, the authors hope to find the reliable and meaningful model in interruption costs of industrial customer.