• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.80-85
• /
• 2008

A PVIB(Photovoltaic in Building) system is united by a constituent outer covering and can expect dual effects that reduce expenses for the establishment of a PV system. It is a profitable technology because it does not need a building as it is a stand alone PV system. This paper presents design, operational features analysis, and PCS(Power Conditioning System) of grid-connected 30kW PVIB set up on the library of Dongshin University. For a sustainable photovoltaic system in this area, the data of the PVIB system are collected and analyzed by monitoring system using LabView. PCS of the grid-connected PVIB system, also, is designed for optimal operation with characteristics suggested in this paper.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.11a
• /
• pp.172-177
• /
• 2008

This study was carry out evaluation of long-term performance for the decentralized desalination system with the solar thermal system and the photovoltaic power system. First operating demonstration system was set up in Cheju in 2006. These system comprises the desalination unit with designed daily fresh water capacity of $2m^3$ and is supplied by a $120m^2$ evacuated tubular solar collector, a $6m^3$ heat storage tank, and a 5kW photovoltaic power generation supply the electricity for hydraulic pumps to move the working fluids. In a clear day more than 400W/$m^2$, the daily fresh water showed to produce more than about 500liter, and from January, 2007 to October, 2008 for 2 years, solar irradiance daily averaged was measured 370W/$m^2$, the daily fresh water yield showed that can be produced about 330liter.

• The KSFM Journal of Fluid Machinery
• /
• v.15 no.6
• /
• pp.39-45
• /
• 2012

This paper describes the outcome of the design of a 200 kW class micro gas turbine and the sensitivity of its performance (efficiency and power) to the variations in major design parameters. The reference design parameters were set up based on the best available component technologies. The resulting net electricity generation efficiency of the micro gas turbine package was found to be competitive to those of other systems in the market. The sensitivities of power and efficiency to the variations in compressor and turbine efficiencies, pressure ratio, turbine inlet temperature, recuperator effectiveness, secondary air ratio, pressure loss ratios of both the cold and hot sides of the recuperator were estimated. Based on the sensitivity data, a simplified method to predict the variation in system performance responding to the combinations of small changes in all design parameters were set up and validated.

• Journal of KIISE:Computer Systems and Theory
• /
• v.35 no.9_10
• /
• pp.476-484
• /
• 2008

Most string problems and their solutions are relevant to diverse applications such as pattern matching, data compression, recently bioinformatics, and so on. However, there have been few works on the relations between string problems and cryptographic problems. In this paper, we consider the following string reconstruction problems and show how these problems can be applied to cryptography. Given a string x of length n over a constant-sized alphabet ${\sum}$ and a set W of strings of lengths at most an integer $k({\leq}n)$, the first problem is to find the sequence of strings in W that reconstruct x by the minimum number of concatenations. We propose an O(kn+L)-time algorithm for this problem, where L is the sum of all lengths of strings in a given set, using suffix trees and a shortest path algorithm for directed acyclic graphs. The other is a dynamic version of the first problem and we propose an $O(k^3n+L)$-time algorithm. Finally, we show that exponentiation problems that arise in cryptography can be successfully reduced to these problems and propose a new solution for exponentiation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.2
• /
• pp.175-181
• /
• 2011

The purpose of this study is to secure the design data for the optimization of the radial turbine and heat cycle system, by using the CFD analysis technique and the design of 100kW class radial turbine applicable to waste heat recovery generation system for ship. Radial turbine was comprised of scroll casing, vane nozzle with 18 blades and rotor with 13 blades, and analysis grid was used to about 2.3 million. Mass flow rate and rotational speed was 0.5kg/s, 75,0000rpm, respectively. Eight kinds of inlet pressure was set between 195 and 620kPa. As the flow accelerated through the nozzle passage to the throat, the pressure level at the pressure and suction sides becomed similar to about Mach number of 0.35. When the inlet temperature and pressure was $250^{\circ}C$, 352kPa respectively, the isentropic efficiency and mechanical power showed the analysis results of 74% and 108kW.

• Journal of the Korean Institute of Gas
• /
• v.9 no.2 s.27
• /
• pp.28-33
• /
• 2005

Because chemical industrial facilities deal with large amount of hazardous materials, the damage affect to off-site as well as on-site when an accident occurs. So it is necessary to develop a Risk Representation System for effective control and response to major accidents. In this study a Risk Representation System(S/W) was developed to help analyzing actual risk and to set an alternative that can reduce the analyzed risk by drawing the level of individual plant's risk on a digital map network.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.3
• /
• pp.276-284
• /
• 2009

In this paper, we develop the image transfer remote maintenance monitoring system for hand held device which can compensate defects of human mistake. The human mistakes always happen when the worker communicate information each other to check and maintenance the equipment of the power plant under bad circumstance such as small place and long distance in power plant. A worker couldn't converse with other when in noisy place like Power plant. So, we make some hand device for handy size and able to converse in noisy place. The developed system can have improvement of productivity through increasing plant operation time. And developed system is composed of advanced H/W(hard ware) system and S/W(soft ware)system. The H/W system consist of media server unit, communication equipment with hand held device, portable camera, mike and head set. The advanced s/w system consist of data base system, client pc(personal computer) real time monitoring system which has server GUI(graphic user interface) program, wireless monitoring program and wire ethernet communication program. The client GUI program is composed of total solution program as pc camera program, and phonetic conversation program etc.. We analyzed the required items and investigated applicable part in the image transfer remote maintenance monitoring system with hand held device. Also we investigated linkage of communication protocol for developed prototype, developed software tool of two-way communication and realtime recording skill of voice with image. We confirmed the efficiency by the field test in preventive maintenance of plant power.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.6
• /
• pp.951-958
• /
• 2008

This paper describes development of hardware simulator for the PMSG wind power system, which was designed considering wind characteristic, blade characteristic and blade inertia compensation. The simulator consists of three major parts, such as wind turbine model using induction motor, PMSG generator, converter-inverter set. and control system. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 2kW PMSG. The PMSG-side converter operates to track the maximum power point, and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was verified by computer simulations with PSCAD/EMTDC, and the implementation feasibility was confirmed through experimental works with a hardware set-up.

• Proceedings of the KIPE Conference
• /
• 2010.11a
• /
• pp.248-249
• /
• 2010

This paper describes development of hardware simulator for the PMSG(Permanent Magnet Synchronous Generator) wind power system, which was designed using real wind data. The simulator consists of a realistic wind turbine model using anemometer, vector drive, induction motor. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 3kW PMSG. The PMSG-side converter operates to track the maximum power point and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was first verified by computer simulations with PSCAD/EMTDC. The feasibility of real system implementation was confirmed through experimental works with a hardware set-up.

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1664-1666
• /
• 2001

This paper presents the development of electromagnetic wave detecting equipment for diagnosis of enclosed switchboard. High voltage power equipments are very important equipment of the key industries and the private enterprise. Power line accidents are national plans because of those set off casualties lose of power equipments and communication networks. Therefore the necessity of the development of detecting for power equipment diagnosis is demand for prevention of high voltage equipment accidents. This paper is the development of electromagnetic wave detecting equipment for diagnosis of high voltage equipment. This paper establishes the diagnosis method for high voltage power equipments, that secures original technique and possesses detecting technique for electromagnetic wave. By the study we developed electromagnetic wave detector, and we applied this equipment application tests at the place constructed high voltage equipments.