• Proceedings of the Korean Nuclear Society Conference
• /
• 2005.10a
• /
• pp.915-916
• /
• 2005

The high power RF system for the PEFP 20MeV proton accelerator composed of the 3MeV RFQ and the 20MeV DTL has been installed. The klystron for the RFQ was tested up to 600kW and operated routinely to drive the RFQ in a pulse mode operation. The klystron for the DTL which consists of 4 tanks was tested up to 800kW in pulse mode operation. The pulse width and repetition rate was 50${\mu}s$ and 1Hz respectively. The high power RF system has been operated to drive each accelerating structure and will be used to accelerate 20MeV proton beam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.75-81
• /
• 2000

Vibration problems induced by an air cooled heat exchanger with axial flow fan were investigated during the operation of a petrochemical plant. Two different studies were done; one was experimental field test and the other was theoretical verification. To find main cause of the blade passing frequency of the fan after installing additional blockage board at the air inlet of the axial fan, the frequency spectrum was measured. The vibrations of the blade passing frequency became higher. The natural frequency of driving support of the heat exchanger was theoretically calculated. It was approximately equal to the blade passing frequency. During the normal operation of the plant, it was impossible to modify the structure of the driving support. Instead, the blade number was increased to reduce vibration level. It increased the ratio of the forcing frequency to the natural frequency of the driving support over the resonance region.

• Journal of the Korean Society of Industry Convergence
• /
• v.9 no.2
• /
• pp.133-139
• /
• 2006

Harmonics happened due to nonlinear systems such as UPS, SCR controlled motors, and fluorescent lighting in distribute power system is very important subject to optimal operation and control of power system. Harmonics sometimes make incorrect operation of protective relaying system under normal condition on power system. In this study, total harmonics distortion(THD) of power were measured and analyzed by the field test on electrical facilities which were installed at the rural industrial complex in Chungbuk province. In addition, the deprivation of power factor by harmonics and the content of THD which is measured at neutral line was researched.

• Transactions of the Society of Information Storage Systems
• /
• v.7 no.1
• /
• pp.7-12
• /
• 2011

The flash memory has been remarked as the next generation media of portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major data storage components for desktop and servers. The purpose of our study is to upgrade a traditional mirroring scheme based on SSD storages due to the relatively slow or freezing characteristics of write operations, as compared to fast read operations. For this work, we propose a new storage management scheme called Memory Mirror-Switching based on traditional mirroring scheme. Our Mirror-Switching scheme improves flash operation performance by switching write-workloads from flash memory to RAM and delaying write operations to avoid freezing. Our test results show that our scheme significantly reduces the write operation delay and storage freezing.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1994.06a
• /
• pp.836-841
• /
• 1994

This paper describes the global vibro-acoustic troubleshooting approach, used to identify and separate different sources of noise and vibrations on a boilerfeed pump testrig. The pump serves for rotor dynamic research of a EC-funded BRITE-Euram profect. This approach resulted in the identification of local structural flexibilities in the connections between the machinery and the base plate. The relative importance of the modes during normal operation is revealed by comparison with operational deformation shapes. The use of sound intensity mapping allowed to calculate the total sound power and to rank the equipment according to its sound power contribution. High acoustic levels were found and related to the fluid drive and to the piping system. Modification of the piping section resulted in a reduction of noise and vibration levels along the test loop and smooth operation in a wide suction pressure range.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.42-44
• /
• 2004

This paper introduced and proposed the voltage unbalance of DC terminal output as new monitoring parameter for power islanding detection. This paper also presented a simple and novel detection algorithm, which effectively combines the detection results of the conventional parameter, voltage magnitude, and a newly proposed parameter. We tested the proposed method using several distribution network conditions including not only islanding operation conditions, but also non-islanding conditions of normal network load variations. The test results showed that the proposed parameters and algorithm are capable of correctly detecting the islanding operation not affected by variation of DG loading and also have a good selectivity for islanding conditions and non-islanding conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.511-518
• /
• 2008

The Engineering Test Satellite VIII(ETS-VIII) of Japan Aerospace Exploration Agency(JAXA) uses a 20mN class xenon ion engine subsystem(IES) for North-South Station Keeping(NSSK). The IES was modified for a larger satellite with longer lifetime based on the former IES. ETS-VIII, a three-ton class geosynchronous satellite with 10 years bus lifetime, was launched 18 Dec. 2006 JST; it reached the planned orbit and all bus systems were checked out. The IES showed good results and is now under normal operation. The total accumulated operation time of the IES in orbit was about 2300 hours till $19^{th}$ Dec. 2007.

• Journal of the Korea Safety Management & Science
• /
• v.18 no.4
• /
• pp.179-183
• /
• 2016

The purposes of this research are to modelize test system of SM TESTING by ARENA, software, input several items of specimen's testing process, resources of system and transfer loop, etc, give a hypothesis and then, obtain results reducing the efficiency of the whole system finally by overload of specific facilities in the testing system through the simulation so as to obtain several materials such as specimen and testing facility, transfer loop, etc. by simple and various forms without any necessity of numerical modelization. It will add facilities of over load and reduce facilities with low operation rate, so increase the efficiency of the system.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.675-680
• /
• 2006

Capacities of a tandem-type air-conditioner may be modulated by turning on and off of multiple compressors, and adjusting the position of a electronic expansion valve. In this study, control algorithms for compressors and a electronic expansion valve were developed by using fuzzy logics. The pressure control algorithm was also developed for the safe operation of compressors. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature,

• Korean Journal of Optics and Photonics
• /
• v.12 no.5
• /
• pp.382-388
• /
• 2001

KITSAT-3, launched at May 26 1999, has an earth observation optical payload named MEIS (Multi-spectral Earth Imaging System). The MEIS is a Managin mirror telescope of aperture size of 95mm, and it images the ground with the ground sampling distance of 13.8m over 48km at the altitude of 720km using three different observations bands. This paper first presents the design and then the optics, relating results of manufacturing, integration and test. Finally it briefly discusses the current status of MEIS operation.