• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2248-2250
• /
• 1999

In this paper, showering discharge type ozonizer has been designed and manufactured. The ozonizer is equipped with three electrodes(central electrode of screw shape, internal electrode and external electrode) of cylinder shape. This paper describes the following two characteristics: (1) The characteristics of discharge with variation of output voltage of AC H.V source, flux of oxygen supplied gas and discharge voltage. (2) The characteristics of ozone generation by varying flux and discharge power.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.3
• /
• pp.109-116
• /
• 2007

Entrepreneurship is considered as the main leadership creating enterprises and employment. However, in Korea empirical studies linking Korean entrepreneurial performances with her characteristics are rarely in existence. Current study focuses on Korean entrepreneurs in manufacturing, construction and other technologically intensive (MCOT henceforth) industries compared to entrepreneurs in service and other technologically less intensive (SOT henceforth) industries and to professional/technical wage workers and examines effects of human capital, demographic, and risk-taking characteristics on earnings. Education premium is higher for entrepreneurs in MCOT industries than for professional/technical workers, even though science and engineering diploma pays better in the latter, and that concentration in college causes more selection into the latter occupational family. In terms of education premium and effects of other characteristics SOT industry entrepreneurship and self-employment appear to be lower grade occupational families, even though there appear to be significant comparative advantages working in their selection.

• Proceedings of the IEEK Conference
• /
• 2000.07a
• /
• pp.237-240
• /
• 2000

We have proposed a simple method based on IIR filters for realizing sound image localization. How-ever the nonlinearity of phase characteristics of the IIR filters, which are used for sound image localization, cause decrease of the localization accuracy. In this paper we investigate the influence of phase characteristics on the sound localization. Head-related transfer functions (HRTFs) of a dummy-head are approximated by the IIR filter. We carried out sound image localization experiment with 2-loudspeaker reproduction using the approximated HRTFs. Then the errors which obtained from experiments were compared with the theoretical values which were estimated from the phase shifts of the IIR filters. As a result there was little influence of the nonlinear phase characteristics of the IIR fitters in the localization on the horizontal plane.

• Journal of electromagnetic engineering and science
• /
• v.11 no.3
• /
• pp.186-191
• /
• 2011

This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size ($14.6{\times}13.2{\times}0.76$ mm) and a low insertion loss when compared with conventional filters.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1998.11a
• /
• pp.156-161
• /
• 1998

The purpose of this paper is to determine circuit parameters in the inverter part of the electronic dimming ballast for fluorescent lamps, that is adequate to use with the prevailing dimming controller IC. Firstly, the operating frequency characteristics are investigated by varying circuit parameters of electronic ballasts and are matched with the output characteristics of dimming ballast controller. Secondly, circuit parameter values are determined by using PSpice simulation and operating frequency characteristics. Finally its validity is verified from the electrical and light output characteristics on the prototype of the electronic dimming ballast.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1354-1356
• /
• 2009

In this paper, we explained characteristics of integral imaging microscope using point light source. To display the bio-medical information, which is captured as a form of the elemental images, using autostereoscopic displays, the characteristics analysis of three-dimensional information is required. For integral imaging microscope using point light source array, the elemental image capturing configuration has to satisfy a specific condition. We explain the condition to capture the elemental images and show the experimental results.

• Transactions on Electrical and Electronic Materials
• /
• v.10 no.6
• /
• pp.196-199
• /
• 2009

The practical applications of piezoelectric ceramics are applied not only under low electric field environment. Therefore, an examination for characteristics of PZT ceramics under the high electric field condition can contribute to reducing the susceptibility of multifarious applications and to facilitating production of control circuits. These contributions can lead to the expansion of industrial applications. In this research, we fabricated disk-type PZT ceramic samples using conventional methods, measured the resonance characteristics of these samples under from low to high voltage conditions and calculated the PZT constants.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.27 no.7
• /
• pp.337-343
• /
• 2015

This paper investigates the ventilation characteristics in a two-dimensional underground network junction composed of four main lines interconnected by eight ramps. Simple one-dimensional models cannot be applied to network junctions since there are interferences of traffic piston effects in the main lines and at the ramps. A numerical algorithm was developed to analyze the pressure and airflow distributions iteratively. The Darcy-Weisbach equation was used to calculate the piston effects by traffic flows, and a Hardy Cross iteration was conducted for network analysis at the interconnected junction. The results show interesting ventilation characteristics and CO concentration distributions depending on system parameters such as vehicle speed, tunnel diameter, and other junction configurations.

• Journal of Korean Association for Spatial Structures
• /
• v.17 no.2
• /
• pp.63-70
• /
• 2017

In Korea, the occurrence frequency of earthquakes has recently increased, compared with the past. So, the various damages for cultural properties due to earthquake can be expected, and especially fortress structure is vulnerable to earthquake. Therefore, the resonable seismic characteristics evaluation is required to secure the safety for fortress structure with the various construction and configuration types. Also, we should consider the various applied load conditions as design variables. To this end, this study classifies fortress structures according to the construction and configuration types, and then applies the discrete element method to model and analyze fortress structures. Finally, the seismic characteristics is evaluated through slip condition due to the analysis results considering the various design variables.

• Journal of the Semiconductor & Display Technology
• /
• v.8 no.1
• /
• pp.7-12
• /
• 2009

The outgassing effects of selected vacuum materials on the vacuum characteristics were simulated by the $VacSim^{Multi}$ simulation tool. This investigation examined the feasibility of reliably simulating the outgassing characteristics of common vacuum chamber materials (aluminum, copper, stainless steel, nickel plated steel, Viton A). The optimum design factors for these vacuum systems were suggested based on the simulation results. The baking-out effects of the modeled systems and materials on the performance of the vacuum system were also analyzed. The simulation predicted that the overall outgassing effect was more significant in the TMP system than in the DP system and that the utilization of a booster pump has a greater effect on the evacuation time than on the ultimate pressure.