• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.4
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• pp.315-324
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• 2005

VOD(video on demand) is a video service by users' order, that is, a video service on demand. That means the users can select and watch the video content that has been saved on sewer, out of broadcasting in the usual process like TV. At present the client of VOD system bases on PC. As the PC-based client uses the software MPEG decoder, the main processor specification has an effect on the capacity. Also people, who don't know how to use their PC, cannot be provided the VOD service. The purpose of this paper is to show the process of the development the VOD client system Into the embedded type with hardware MPEG-4 decoder. The main processor is the SC1200 of x86 Family in National Semiconductor with a built-in video processor and the memory is 128Mbyte SDRAM. Also, in order that the VOD service can be provided using the Internet, the Ethernet controller is included. As the hardware MPEG-4 decoder is used in the embedded VOD client system, which is developed, it can make the low capacity of the main processor. Therefore it is able to be developed as a low-price system. The embedded VOD client system is easy for anyone to control easily with the remote control and can be played through TV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1113-1124
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel fur the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit of a field synchronized with the A/D converter. The implemented H/W used the 69%(16980) LAB(Logic Array Block) and 9%(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation of 60 fields/sec(30 frames/sec).

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.1-17
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• 2015

A river water level monitoring system which prevents salt water damages and effectively excludes floods has been developed to contribute efficient operation of Nakdong river estuary barrage. The system can be used for monitoring upstream conditions more quickly and do appropriate responses over changes. Telemetry and telecontrols using PLCs have been built at the three sites that directly influence on the operation of barrage gates, and are linked to Nakdong river estuary barrage's IOS (Integrated Operation System) through public communication networks. By using PLC, the system can achieve even higher reliability and versatility than before as well as easy management. By power control devices, we can remotely control the power of PLCs to treat the minor troubles instantly without going on-sites. The power control devices also save data in preparation for the cases of communication failures. The system uses ADSL (FTTH) as a main network between SCADA server and PLCs, and CDMA (M2M) as a secondary network. In order to compensate security vulnerabilities of public communication network, we have installed the VPNs for secure communication between center and the observation stations, just like a dedicated network. Generally, river water level observations have been used custom-manufactured remote terminals to suit their special goals. However, in this case, we have established a system with open architecture considering the interface between different systems, the ease of use and maintenance, security, price, etc.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.269-277
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• 1996

The vacuum systems of PLS linac provides average pressure of $2.6\times 10^{-6}$Pa under high power microwave of 54 MW peak with 4.1 $\mu \textrm s$ pulse width and 10 Hz repetition rates. The base pressure of system is$2.4\times 10^{-6}$Pa with 45$^{\circ}C$ cooling water. The outgassing rate of the system is decreased from $3.0\times 10^{-11}Torr-l/sec-\textrm{cm}^2$ at the initial stage after installation to $1\times 10^{-12}Torr-l/sec-\textrm{cm}^2$ at present. Total accumulated microwave energy dose is about 140 GJ per module. All ion pumps are working under saturated regime and effective pumping speeds of 60 I/s, 230 I/s ion pumps are 45 I/s, 65 I/s, 140 I/s under the operating range. Main problems occurred in recent year are troubles of ion pump controller and vacuum gauge controller, vacuum leak of energy doubler window and electron gun ceramic, and water leak in the dummy load of acceleraing columns. Total of 41 troubles with 140. 8 hours down time give good system availability of 98%. Down time can be reduced by high power waveguide valves and water dummy loads under development, and then availability is expected to be increased up to 99.5%.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.315-319
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• 1996

We have developed a prototype patient monitoring system including module-based bedside units, interbed network, and central stations. A bedside unit consists of a color monitor and a main CPU unit with peripherals including a module controller. It can also include up to 3 module cases and 21 different modules. In addition to the 3-channel recorder module, six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmogaph are provided as parameter modules. Modules and a module controller communicate with up to 1Mbps data rate through an intrabed network based on RS-485 and HDLC protocol. Bedside units can display up to 12 channels of waveforms with any related numeric informations simultaneously. At the same time, it communicates with other bedside units and central stations through interbed network based on 10Mbps Ethernet and TCP/IP protocol. Software far bedside units and central stations fully utilizes gaphical user interface techniques and all functions are controlled by a rotate/push button on bedside unit and a mouse on central station. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances. In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we are developing a relational database server dedicated to the patient monitoring system. We are also developing a clinical workstation with which physicians can review and examine the data from patients through various kinds of computer networks far diagnosis and report generation. Portable bedside units with LCD display and wired or wireless data communication capability will be developed in the near future. New parameter modules including cardiac output, capnograph, and other gas analysis functions will be added.

• The KIPS Transactions:PartD
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• v.12D no.6 s.102
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• pp.889-898
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• 2005

Recently, one of the most challenging problems is to compose web services dynamically, that is, on demand. A number of researchers have been considerably interested in the dynamic web services composition. However, while most of them focused on the semi-automatic web services composition with a human controller, very little attention was devoted to the full automation of this process. This paper primarily focuses on the automatic web services composition techniques. The main idea is to implement an automatic web services composition system using web ontologies to realize the semantic web and workflow technologies to play a major role in E-businesses. In this paper, we propose a matching algorithm for web service discovery and present an approach based on the use of ontologies to facilitate the interoperability of web services. Finally, we describe a workflow execution plan to support the automatic web services composition, and an experimental study that shows the high performance of our system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.184-190
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• 2014

Until now ship communication micro serial network communication method is designed for the communication between the controller and the RS-422 communication on the international standard ISO 1993, but gradually progresses NMEA 2000 standardized fast Ethernet-based communications environments expected to be replaced. In addition, the ship's main instrumentation equipment versatility with ease gradually to control devices by monitoring and controlling are. Wind anemometer, ship mast end, where the highest wind farms typically install a separate console boxes, data loggers, indicators was required in order to manage them, to maintain them, to go through the procedures and cumbersome data update firmware were Therefore, in this paper, using the PC network, ultrasonic wind speed data processing system for implementing functional was expressed as a function of the technology elements, NMEA 2000 standard certified in separate operating console without the features of the data loggers, indicators, implementation by ultrasonic wind data processing system was implemented to minimize the maintenance cost of the operating system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.1-8
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• 2012

Recently, the needs of system performances such as working speed and processing accuracy in machine tools have been increased. Especially, the speed increment generates harmful heat at both moving part of the machine tools and handicrafts. The heat is a main drawback to progress accuracy of the processing. Hence, a cooler system to control temperature is inevitable for the machine tools. In general, two representative control schemes, hot-gas bypass and variable speed control of a compressor, have been adopted in the water cooler system. In this paper, comparisons of system performances according to the control schemes in a cooler for machine tools were conducted in detail. Each proportional-integral feedback controller for the two different control systems is designed. The system performances, especially the temperature control accuracy and coefficient of performance which is a criterion of energy saving, were mainly analyzed through various experiments using 1RT water cooler system with different two types of control scheme. These evaluations will provide useful information to choose suitable water cooler system for the engineers who design controllers of the cooler system for machine tools.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.2
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• pp.130-135
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• 2013

Recently, the needs of system performances such as working speed and processing accuracy in machine tools have been increased. Especially, the working speed increment generates harmful heat at both moving part of the machine tools and handicrafts. The heat is a main drawback to progress accuracy of the processing. Hence, a oil cooler to control temperature is inevitable for the machine tools. In general, two representative control schemes, hot-gas bypass and variable speed control of a compressor, have been adopted in the oil cooler system. In this paper, the compressor's speed are controlled to keep reference value of temperature at oil outlet. The precision processing of a machine tool is required for an oil cooler guaranteeing ${\pm}0.1^{\circ}C$ temperature control. But the oil cooler with precision temperature control is expensive. Therefore in this paper, instead of a on/off(relay) control method, a PID and phase angle electric power control method is proposed for the precision control of an oil cooler. The proposed controller is implemented and tested at the temperature of $23^{\circ}C$, $24^{\circ}C$ and $25^{\circ}C$.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.42-48
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• 2020

This research illustrates how the hybrid engine system comprising of a two-cycle reciprocal engine with an integrated generator and a battery is prepared for the design process. The purpose of this research is to increase flight endurance taking advantage of the high energy density of hybrid propulsion systems as well as to cope with current environmental issues by reducing fossil fuel. The hybrid system is designed to offer 6 kW power, and the power can be adjusted by controlling the engine's RPM in accordance with load variations. In addition, the battery is adopted to offer extra electric power that this hybrid system cannot cover, and can function as the main power source in limited time in the case of an emergency situation. Besides that, the generator is directly mounted on an engine crank-shaft, and in turn, they can share the same RPM. Thus, it is hypothesized that this integration method can make a compact design possible by reducing space for the installation in the fuselage of UAVs.