• 한국컴퓨터정보학회논문지
• /
• 제23권2호
• /
• pp.1-7
• /
• 2018

The adaptive optics for compensating for optical wavefront distortion due to atmospheric turbulence has recently been used in systems that improve beam quality by eliminating the aberrations of high power laser beam wavefront. However, unseen-mode, which can not be measured in the wavefront sensor, increases the instability of the laser beam wavefront compensator on the adaptive optics system. As a method for improving such instability, a mathematical method for limiting the number of singular values is used when generating the command matrix involved in generation of the drive command of the wavefront compensator. In the past, however, we have relied solely on experimental methods to determine the limiting range of the singular values. In this paper, we propose a criterion for determining the limiting range of the singular values using the driving characteristics and the correlation technique of the wavefront compensator's actuators and have proved its performance experimentally.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 추계학술대회 논문집
• /
• pp.811-815
• /
• 2005

Traditional passive suspension has limitations to meet the required specifications of high level trains, and so Active suspension system is proposed to meet the requirements with active components which could be controlled by external signal for optimized behavior of train. Active suspension is to be divided by Full active suspension and Semi-active suspension whether using the external power source or not, and though the performance of Semi-Active suspension is worse than Full one. Semi-active suspension is focused with its effectiveness per cost. Semi-Active suspension system consists of sensors, ECU (electrical control unit), and variable damper, which are to be designed to be fit for train system. And the software of ECU is to be developed for to be suited to its dynamic behavior through simulation result calculated by proven model. In this experimental study, the hardware and software of semi-active suspension system is to be realized and its performance for improvement of ride quality to be confirmed through roller rig test.

• 한국신뢰성학회:학술대회논문집
• /
• 한국신뢰성학회 2005년도 학술발표대회 논문집
• /
• pp.303-305
• /
• 2005

Recently, various plastics are used for improvement of reliability and thermal stability of electronic goods. But, it is difficult to choose suitable balance of grade resin to each other product property. Selection of high efficiency resin is becoming inescapable circumstance according to change of reflow temperature of product and development of product following to lead free. Using a inexpensive and reasonable resin, that sustain a uniform performance of product quality. It is make a robust product and increase a company's competitive power. Hereupon, I introduce example that use ESPI methods of thermal deformation analysis of product using in our company product. I try to refer to a structural weak point detection of real time measurement of electronic parts instead of mechanical and chemical measurement of specimen type.

• 한국항공운항학회지
• /
• 제29권1호
• /
• pp.61-73
• /
• 2021

PAV is considered to improve quality of life and standards of living, improvement of which was caused by automobile hundred years ago. Comparative economic efficiency of PAVs is measured to compare each PAV. Specification and sales price of the PAVs are open to the public. BlackFly, Transition and Aeromobil 3.0 have competitive power in flying range, purchasing cost, and operational cost. Lift & cruise configuration and vectored thrust configuration PAVs are designed by many companies nowadays, and BlackFly which can be considered to be lift & cruise configuration is one of the most efficient PAVs. High battery price does not help multi-copter shaped PAVs to have economic efficiency. Aerodynamic wing, eVTOL, and low sale price are needed for PAVs to ride a wave of public interest as a new personal mobility. Under the conditions, the PAV can fly at downtown and can be purchased by people at large. Popularization of PAV could follow in the 100 years old footsteps of automobile.

• 분석과학
• /
• 제8권4호
• /
• pp.799-806
• /
• 1995

In industrial field, a large volume of regenerants (acid and caustic soda) and their washing effluents are regularly disposed off from the water demineralization plant during regeneration of the ion-exchanger units. Of these waste effluents, a part of the wash water discharged from the single bed Anion and Mixed Bed units can be utilized at a certain stage of their washing cycles when its conductivity is fallen down and becomes considerably less than that of the input raw water. The main aim of this specific waste effluent utilization is to dilute the TDS concentration of the input raw water (fed into the single bed ion-exchanger units) by blending. The achievement is the increase of the longevity of the production cycles of the I.E. units along with the improvement of the production quality and decrease of the regeneration frequencies. As a result, regenerant consumption would be saved because of the reduction of ionic load in feed water which will ultimately reduce the water purification cost. At the same time, the environment pollution will also be protected to a considerable extent. This operational measure is quite effective and useful specially where high TDS water is demineralized only by single bed ion-exchangers. In such case, the water treatment plant is very often found to suffer from both production quality and quantity in addition to carrying out of random and restless regenerations. Proper reuses of the aforesaid wash water effluents of the Anion and MB units excellently minimizes the difficulties experienced in practice. This paper contains the utilities and techniques of reuses of the different kinds of waste effluents of the industrial water treatment plant in addition to the specific reuses of the post-regeneration wash waters of the Anion and MB ion-exchanger units.

• 대한전자공학회논문지SP
• /
• 제49권1호
• /
• pp.104-111
• /
• 2012

본 논문에서는 향상된 최소값 제어 재귀 평균 기법 (improved minima controlled recursive averaging, IMCRA) 알고리즘의 잡음 전력 추정성능을 향상 시키기 위한 알고리즘을 제안한다. 기존의 IMCRA은 주파수 특성이 빠르게 변화하는 비정상적인 환경과 낮은 SNR을 갖는 상황에서 잡음 전력 추정에 직접적으로 영향을 미치는 음성 검출기의 성능이 강인하지 못한 단점이 있다. 본 연구에서는 강인한 음성 검출 성능을 위해서 기존 IMCRA의 음성 검출기에 전역 음성 부재 확률을 적용한 음성 향상 기법을 제안한다. 제안된 알고리즘의 성능 평가는 음성의 perceptual evaluation of speech quality (PESQ)와 composite measure를 통한 음질을 평가하였다. 실험 결과 다양한 잡음 환경 (car, white, babble)에서 전역 음성 부재 확률을 적용한 IMCRA의 음성 향상 기법이 향상된 결과를 보여주었다. 특히, 비정상잡음 환경인 babble 5dB에서 PESQ 0.026, composite measure 0.029의 향상된 음질을 나타내었다.

• 플랜트 저널
• /
• 제18권3호
• /
• pp.41-51
• /
• 2022

최근 LNG발전소 건설이 늘어나고 주민들의 삶의 질 향상 욕구가 증가함에 따라 건설 추진과정에서 주민과의 갈등으로 인한 건설사업 지연으로 전력수급 안정화를 저해하거나 사회적 비용이 증가하는 실정이다. 이에 주민 수용성 강화방안을 연구하여 추후 발전소 건설추진에 도움이 되었으면 하는 바람에서 이 연구를 하였다. 여기서는 주민들의 반대가 가장 심한 단계이며 사업 지연으로 인한 경제적·사회적 손실발생은 물론 극단적일 경우 사업취소까지 연결될 수 있는 입지선정 단계에 한해서 연구를 하였다. 이를 위해 최근 10년 이내 준공한 LNG발전소 준공지연사례를 통해 수많은 발전소가 당초 계획보다 짧게는 수개월에서 길게는 몇 년씩 준공이 지연된 사례를 살펴보았으며, 특히 음성천연가스발전소와 대구LNG발전소 건설 준비중 갈등사례를 분석하여 주민 수용성 제고를 위해서는 첫째 발전소 입지 선정 시 주민의견 수렴이 필요함을 알 수 있었고 둘째 발전소 주변지역 지원에 관한 법률 정비 등 법규 개정이 수반되어야 하며 셋째 발전설비 최신기종 선정 등 환경 친화적 설비구성에 최선을 다해야 함을 알 수 있었다.

• Progress in Superconductivity
• /
• 제14권1호
• /
• pp.66-70
• /
• 2012

Superconductor flywheel energy storage system (SFESs) is an electro-mechanical battery with high energy storage density, long life, and good environmental affinity. SFESs have been developed for application to a regenerative power of train, the storage of distributed power sources such as solar and wind power, and a power quality improvement. As superconductor bearing is completely passive, it is not necessary to control a system elaborately but accurate analysis in mechanical properties of the HTS bearing is very important for application to SFESs. Stiffness and damping properties are the main index for evaluation the capacity of HTS bearings and make it possible to adjust rotordynamic properties while operating the rotor-bearing system. The superconductor bearing consists of a stator containing single grain YBCO bulks, a ring-type permanent magnet rotor with a strong magnetic field that can reach the bulk surface, and a bearing support for assembly to SFESs frame. In this study, we investigated the stiffness and damping properties of superconductor bearings in 35 kWh SFESs. Finally, we found that 35 kWh superconductor bearing has uniform stiffness properties depend on the various orientations of rotor vibration. We discovered total damping coefficient of superconductor bearing is affected by not only magnetic damping in superconductor bulk but also external damping in bearing support. From the results, it is confirmed that the conducted evaluation can considerably improve energy storage efficiency of the SFESs, and these results can be used for the optimal capacity of superconductor bearings of the SFESs.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권1호
• /
• pp.17-21
• /
• 2012

The purpose of this study was to improve mapping power and resolution for the QTL influencing carcass quality in Hanwoo, which was previously detected on the bovine chromosome (BTA) 6. A sample of 427 steers were chosen, which were the progeny from 45 Korean proven sires in the Hanwoo Improvement Center, Seosan, Korea. The samples were genotyped with the set of 2,535 SNPs on BTA6 that were imbedded in the Illumina bovine 50 k chip. A linkage disequilibrium variance component mapping (LDVCM) method, which exploited both linkage between sires and their steers and population-wide linkage disequilibrium, was applied to detect QTL for four carcass quality traits. Fifteen QTL were detected at 0.1% comparison-wise level, for which five, three, five, and two QTL were associated with carcass weight (CWT), backfat thickness (BFT), longissimus dorsi muscle area (LMA), and marbling score (Marb), respectively. The number of QTL was greater compared with our previous results, in which twelve QTL for carcass quality were detected on the BTA6 in the same population by applying other linkage disequilibrium mapping approaches. One QTL for LMA was detected on the distal region (110,285,672 to 110,633,096 bp) with the most significant evidence for linkage (p< $10^{-5}$). Another QTL that was detected on the proximal region (33,596,515 to 33,897,434 bp) was pleiotrophic, i.e. influencing CWT, BFT, and LMA. Our results suggest that the LDVCM is a good alternative method for QTL fine-mapping in detection and characterization of QTL.

• 한국환경보건학회지
• /
• 제17권1호
• /
• pp.57-66
• /
• 1991

This study was carried out for 5 years between 1984 and 1986 and 1989 and 1990. This interviewers visited 292 households to evaluate the perception of the residents using .the. Simple Piped Water Supply (SPWS), and examined the pollution source surrounding 42 SPWS facilities and water quality by the chemical and microbiological method. The purpose of this study was to find out problems linked with SPWS and to investigate more efficient way of improvement in rural water supply. The results of the study are surmnarized as follows: 1) Approximately 55% of the sampled population have been served by simple piped water supply. 2) The drinking water was mostly taken from the springs in 16 sites and valley water in 26 sites. 3) Considering the type of distribution of the SPWS, there are 28 natural gravity systems and 14 pumping systems. 4) Out of the 180 SPWS in Chun Sung Area, 74% of the SPWS facilities were used more than ten years. In addition, 40% of residents expressed the need for repairs of old facilities. 5) 48% of the SPWS facilities are neighbored with pollution source. 6) 50% of the maintenance crews were not committed totheir job but instead, the facilities were operated by some residents or community leaders who were personally concerned about quality of the facilities. 7) About 85% of the residents answered that SPWS was convenient and helpful. 8) About 57% of the residents complaind that the amount of daily water supply is not adequate. 9) About 74% of the residents felt that the water quality is high for dringking water and therefore, 52% of the facilities were not properly chlorinated. But in contrast, the biochemical tests indicated that only 28% of the SPWS met the dringking water quality standards. 10) Maintenance cost per a household ranges form 500 to 2, 000Won (1 $ = 700 Won) a month. Most of the cost was to cover the power electric charge. For the effective maintenance and arrangement of the facilities, gorvermental financial support for the maintenance is strongly recommended.