• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.3
• /
• pp.599-603
• /
• 2010

A point-mesh type corona system has been well used as a ionic wind blower. However this type corona system suffers from its lower ionic wind generation, because of its lower on-set and breakdown voltages of its very sharp needle point corona electrode. This means that the point corona electrode must act both as an effective ion-generator and a very higher electric field producer in the discharge airgap in order to generate higher ionic wind velocity. In this paper, a cylinder-mesh type discharge system as a ionic wind generator is proposed and investigated. The cylindrical corona electrode can produce many ions from its sharpened edge, and the corona on-set and breakdown voltages are very higher than those of the needle point corona electrode. As a result, this type cylindrical corona electrode might generate a higher ionic wind than the needle point corona electrode.

• Solar Energy
• /
• v.18 no.1
• /
• pp.81-89
• /
• 1998

In this paper an experimental was done to design combustion chambers which is required radiation strength of high temperature generator of absorption rigerator. Partiqularly, in combustion chamber radiative mediums were set and basic experiments were done according to its size by radiation strength and effects of heat transfer promotion. The results are as follows : 1) When radiative mediums were set in small combustion furnace burning nonframely radiative heat transfer was effected. 2) In case that area ratio($A/A_o$) of radiative medium is 0.82 or over, temperature fluctuation effects of furnace inside were not nearly. 3) In experimental boundary heat transfer effects were 1.8 times by setting up radiative medium. Specially, $q/{\Delta}T$ values of furnace inside were uniformed nearly by setting up radiative mediums.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.3 no.1
• /
• pp.136-142
• /
• 1995

An analysis model is proposed for the performance prediction of typical ball and tube type mechanical crash sensors based upon mass-spring-viscous gas damping idealization. Also a construction of mechanical crash pulse generator is suggested as an experimental tool for calibration and verification of model predictions. A sensor tuning procedure for a particular set of crash pulses is suggested based upon the analysis model and the experimental tools.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1182-1183
• /
• 2008

In this paper, we develop PCS for doubly-fed induction-type wind generator(DFIG). PCS consists of a converter set and a controller. PCS controls the active power of wind generator and the reactive power of wind turbine system according to rotating speed, instantaneous power, grid quality, and order by transmission system operator.

• Communications of the Korean Mathematical Society
• /
• v.34 no.4
• /
• pp.1329-1334
• /
• 2019

We define the concept of a generator for a ${\mathbb{Z}}^k$-action T and show that T is expansive if and only it has a generator. Further, we prove several properties of a ${\mathbb{Z}}^k$-action including that the least upper bound of the set of expansive constants is not an expansive constant.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.1
• /
• pp.73-80
• /
• 2004

In this paper, a maximum output power control of stand-alone cage-type induction generator systems for wind power generation is proposed. The induction generator is operated in a vector-controlled mode, which is excited with d-axis current and of which torque is controlled with q-axis current. The generator speed is controlled by this torque, along which speed the generator produces the maximum output power. The generated power charges the battery bank for energy storage through an ac/dc PWM converter. The proposed scheme has been verified for the wind turbine simulator system which consists of M-G set.

• Journal of the Korean Institute of Gas
• /
• v.20 no.4
• /
• pp.58-64
• /
• 2016

The main engine of a vehicle is used an common rail diesel engine for improving the efficiency of the whole load area. However, the generator engines is still used mechanical fuel injection valve drive cams. In addition, most of generator engines is applied a part-load operation of less than 50%. Therefore, diesel engine of vehicle set at 100% load is necessary to readjust in order to perform efficient operation because of part-load operation. In this study, the objective is to report the results of the part-load fuel consumption improvement by injection timing readjust to identify the operational characteristics of a generator engine currently operated in the facilities.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.5
• /
• pp.1076-1085
• /
• 2001

Experimental investigations of the longitudinal vortices, which are produced by wing type vortex generators set up behind a circular cylinder in a rectangular channel, are presented. When the circular cylinder is set up in the rectangular channel, a horseshoe vortex is formed just upsteam of the circular cylinder. It generates a turbulent wake region behind the circular cylinder. Therefore, the region of the pressure loss behind the circular cylinder in increased and the size of the wake is small. These problems can be achieved by longitudinal vortices which are generated by wing-type vortex generator. In order to control the strength of longitudinal vortices, the angle of attack of the vortex generators is varied from 20 degree to 45, but the spacing between the vortex generators is fixed 6cm. The 3-dimensional mean velocity measurements are made using a five-hole probe. The vorticity field and streamwise velocity contour are obtained from the velocity field. The following results are obtained. Circulation strength is the maximum value when the angle of attack($\beta$) is $30^{\circ}$, and the vorticity field and streamwise velocity contour in case of $\beta$=$20^{\circ}$ show the trend similar to these in case of $\beta$=$30^{\circ}$, but do not in case of $\beta$=$45^{\circ}$.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.5
• /
• pp.545-550
• /
• 2012

Steam generator is one of the major components of nuclear power plant and steam generator tubes are the pressure boundary between primary and secondary side, which makes them critical for nuclear safety. As the operating time of nuclear power plant increases, not only damage mechanisms but also scaled deposits on steam generator tubes are known to be problematic causing tube support flow hole blockage and heat fouling. The ability to assess the extent and location of scaled deposits on tubes became essential for management and maintenance of steam generator and eddy current bobbin data can be utilized to measure thickness of scale on tubes. In this paper, tube reference standards with various thickness of scaled deposit has been set up to provide information about the overall deposit condition of steam generator tubes, providing essential tool for steam generator management and maintenance to predict and prevent future damages. Also, methodology to automatically measure scale thickness on tubes has been developed and applied to field data to estimate overall scale amount.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.8
• /
• pp.95-101
• /
• 2009

Random numbers are used in many sorts of applications. Some applications, like simple software simulation tests, communication protocol verifications, cryptography verification and so forth, need various levels of randomness with various process speeds. In this paper, we propose a fast pseudorandom generator module for embedded systems. The generator module is implemented in hardware which can run in two modes, one of which can generate random numbers with higher randomness but which requires six cycles, the other providing its result within one cycle but with less randomness. An ASIP (Application Specific Instruction set Processor) was designed to implement the proposed pseudorandom generator instruction sets. We designed a processor based on the MIPS architecture,, by using LISA, and have run statistical tests passing the sequence of the Diehard test suite. The HDL models of the processor were generated using CoWare's Processor Designer and synthesized into the Dong-bu 0.18um CMOS cell library using the Synopsys Design Compiler. With the proposed pseudorandom generator module, random number generation performance was 239% faster than software model, but the area increased only 2.0% of the proposed ASIP.