• 음성과학
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• 제13권1호
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• pp.117-128
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• 2006

The two-channel Generalized Sidelobe Canceller (GSC) scheme suffers from the presence of leakage signal in the reference channel. The leakage signal is caused by the dissimilar impulse responses between microphones, and different paths from speech source to microphones. Such leakage is detrimental to speech enhancement of the GSC since the desired reference signal becomes corrupted. In order to suppress the signal leakage, two matrix injection methods are proposed. In the first method, a simple gain compensation matrix is used. In the second, a projection matrix for reducing the error between the actual and the ideal primary and reference signals, is used. This paper describes the performance degradation resulting from leakage, and proposes effective methods to resolve the problem. Representative experiments were conducted to demonstrate the effectiveness of the proposed methods on recorded speech and noise in an actual automobile environment.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.73-80
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• 1999

Leakage vortices formed new blade tip causes an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of the tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated by varying the tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the loss distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.104-107
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• 2018

In this paper, we developed a sensor for monitoring the leakage current through the chassis of the robot. The leakage current sensor needs to be developed because it is a necessary part to prevent electric shock accidents that may occur through the chassis of a robot or an electric vehicle. This leakage monitoring sensor was developed to be mounted directly on the chassis of the robot. This sensor protects the control system from noise by discharging static and high-frequency noise that may occur in the chassis of the robot and monitors the leakage current by measuring the amount of current discharged through the ground. In this paper, a leakage monitoring sensor was developed with a simple structure using resistors, capacitors and OP-AMP, and the performance was evaluated.

• 디지털융복합연구
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• 제15권7호
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• pp.159-167
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• 2017

지난 5년간 국가기술의 약 200여건이 해외로 유출되었으며, 그 중의 70% 이상이 중소기업이며, 내부유출은 80%에 이르는 것으로 통계자료(국가정보원 산업기밀보호센터)를 통해 확인 할 수 있다. 이는 중소기업내의 내부유출 방지에 대한 정부의 산업기술 유출방지를 위한 정책이 중소기업에 집중되어야 한다는 것이다. 특히 기술유출 피해경험이 기업규모에 따라 유출방지 성과에 미치는 영향에 대해 분석한 연구는 전무하며 산업기술 유출에 대한 요인을 조사한 연구 또한 미약한 실정이다. 본 연구는 기존의 선행되어진 국, 내외의 연구들을 분석하여 산업기술 유출방지 성과에 미치는 요인을 바탕으로 각각의 특성들을 성질화 하여 변인들을 각각 TOE 프레임워크와 TAM모델을 적용하여 성과와의 영향관계를 실증 분석하였다. 산업기술 내부 유출을 보호하기 위하여 정부정책, 회사의 방향성 등이 어떤 영향을 미치는지 분석하여 방향성을 제시하는 것이 산업기술의 내외적인 유출보호에 대하여 기업과 조직에게 시스템 구축과 인력관리에 대한 실무적 시사점을 제공해줌으로써 정책과 제도를 수립하는데 방향성을 제시하고자 연구를 진행하였으며, 이에 따른 보다 올바른 방향성 제고에 그 의미를 두고 있다.

• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.606-616
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• 2003

A numerical analysis has been conducted in order to simulate the characteristics of complex flow through linear cascades of high performance turbine blade with/without tip clearance by using a pressure-correction based, generalized 3D incompressible Wavier-Stokes CFD code. The development and generation of horseshoe vortex, passage vortex, leakage vortex, tip vortex within tip clearance, etc. are clearly identified through the present simulation which uses the RNG k-$\varepsilon$ turbulent model with wall function method and a second-order linear upwind scheme for convective terms. The present simulation results are consistent with the generally known tendency that occurs in the blade passage and tip clearance. A 3D model for secondary and leakage flows through turbine cascades with/without tip clearance is also suggested from the present simulation results, including the effects of tip clearance height.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.912-915
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• 2004

A vacuum environment is very important for NGL(Next Generation Lithography) apparatuses such as EUVL(Extreme Ultra Violet Lithography) or EPL(Electron Projection Lithography) and so on. The performance of these systems is dominated by vacuum level of processing and positioning accuracy of a stage. So, ultra-precision stage usable in a high vacuum level is needed for the improved performance of these devices. In contrast to atmospheric condition, a special attention must be paid to guide bearing, actuator and other elements. In this paper, air bearing is adopted because of its very high motional accuracy. So, air bearing is designed to be vacuum compatible using differential exhaust method, which prevents air from entering into vacuum chamber. For this, leakage analysis is performed theoretically and verified from experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.744-749
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• 2001

As related to rotordynamics, dynamic characteristics of the wear ring seal in high pressure multi-stage pump is calculated in the cases of labyrinth, damper and helically grooved types. The. results show that the labyrinth seal type has superior performance in the view point of leakage. However, in terms of rotordynamics view point, the damper seal type gains acceptable separate margin in critical speed range, while it has slightly inferior leakage performance compared to labyrinth seal type.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.159-163
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• 2007

We studied the example of various side on effect the aging of exterior materials for concrete structure by analyzing the reason of water leakage in exist serviced skyscraper apartment. For this side, we would like to suggest the proper waterproofing materials and construction methods resulted in the mechanical performance test. So, it could be ensured the leakage safety for using residence facility and crowd utilization after repairing. It may maximize the durability for the concrete structure.

• ETRI Journal
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• 제30권4호
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• pp.624-626
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• 2008

Excessively high temperature deteriorates the reliability and increases the leakage power consumption of microprocessors. The register file, known as one of the hottest functional units in microprocessors, incurs frequent dynamic thermal management operations for thermal control. In this letter, we adopt the banked register file scheme, which was originally proposed to reduce dynamic power consumption. By simply modifying the register file structure, the temperature in the register file was reduced dramatically, resulting in 13.37% performance improvement and 10.49% total processor leakage reduction.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.979-989
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• 2004

Numerical simulations have been performed to investigate tip clearance effect on through-flow and performance of a centrifugal compressor which has the same configuration of impeller with six different tip clearances. Secondary flow and loss distribution have been surveyed to understand the flow mechanism due to the tip clearance. Tip leakage flow strongly interacts with mainstream flow and considerably changes the secondary flow and the loss distribution inside the impeller passage. A method has been described to quantitatively estimate the tip clearance effect on the performance drop and the efficiency drop. The tip clearance has caused specific work reduction and additional entropy generation. The former, which is called inviscid loss, is independent of any internal loss and the latter, which is called viscous loss, is dependent on every loss in the flow passage. Two components equally affected the performance drop as the tip clearances were small, while the efficiency drop was influenced by the viscous component alone. The additional entropy generation was modeled with all the kinetic energy of the tip leakage flow. Therefore, the present paper can provide how to quantitatively estimate the tip clearance effect on the performance and efficiency.