• Journal of the Korean Statistical Society
• /
• v.23 no.2
• /
• pp.421-444
• /
• 1994

Reliability acceptance sampling is concerned with whether to accept or reject a collection of items based upon the information obtained from life testing. Although various reliability acceptance sampling plans have been developed, little is known about their relatvie performances. This paper compares reliability acceptance sampling plans under Type II censoring, Hybrid censoring, and Time-Truncated Type II censoring assuming that the lifetimes of items in a lot follow an exponential distribution. The three plans are compared in terms of the power, the expected number of failures, and the expected time required to reach a decision. Computational experiments are conducted and the results are tabulated to provide guidelines for selecting an appropriate plan for a given situation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.1
• /
• pp.1-7
• /
• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.1 s.94
• /
• pp.61-67
• /
• 1999

A laser Doppler vibrometer based on the laser heterodyne interferometry is employed to measure the vibration velocity of vibrating objects. In this paper, we propose a real time analog signal processor of a laser Doppler vibrometer to reduce the degradation of Doppler signals mainly caused by environmental noises. In the proposed real time signal processor of an laser Doppler vibrometer, a pre-processor and a logical motion direction detector are designed to reduce the detection errors of the object motion direction. Also, a noise detection and rejection circuit is designed to reject the unfiltered noises.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.8
• /
• pp.697-702
• /
• 2001

The ring laser gyro(RLG) has been used extensively in strapdown inertial navigation system(SDINS) because of the apparent of having wide dynamic range, digital output and high accuracy. The dithered RLG system has dynamic motion at sensor level, caused by the dithering motion to overcome the lock-in threshold. In this case, an attitude error is produced by not only the true coning of the vehicle motion but also the pseudo coning of the sensor motion. This paper describes the definition of the multi-frequency coning motion and its noncommutativity error to reject the pseudo coning error produced by the sensor motion such as the dithered RLG. The simulation results are presented to minimize the multi-frequency coning error.

• Proceedings of the KIEE Conference
• /
• 2003.11b
• /
• pp.223-226
• /
• 2003

This paper presents a realization of sensor signal processing(noise filtering) and Fieldbus based communication for condition monitoring of check valve. we first acquired the AE(Acoustic Emission) sensor data at the KAERI check valve test loop, and their frequencies were analyzed to find the informative band. To reject background noises, bandpass filters have been designed. Also, to send the processed data to a remote site, wired communication facility has been realized via DeviceNet.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.3
• /
• pp.382-389
• /
• 2013

In anti-jamming GPS receiver, adaptive signal processing techniques in which the radiation pattern of adaptive array antenna of elements may be adaptively changed used to reject interference, clutter, and jamming signals. In this paper, I describes adaptive signal processing technique using the sample matrix inversion(SMI) algorithm. This adaptive signal processing technique can be applied effectively to wideband/narrowband anti-jamming GPS receiver because it does not consider the satellite signal directions and GPS signal power level exists below the thermal noise. I also analyzed the effects of covariance matrix sample size and diagonal loading technique on the system performance of five-element circular array antenna. To attain near optimum performance, more samples required for calculation covariance matrix. Diagonal loading technique reduces the system nulling capability against low-power jamming signals, but this technique improves robustness of adaptive array antenna.

• Journal of the Korean Society for Precision Engineering
• /
• v.9 no.1
• /
• pp.53-65
• /
• 1992

For improving the performance of maglev systems with a combined lift and guidance, it is suggested that the multivariable control systems and a secondary suspension should be added. The former is required to reject both track irregularities in vertical disturbances and wind gusts in lateral disturbances, and the latter to guarantee passengers against an unsatisfied criteria in ride quality. In this paper, bond graph model for the study of nonlinear dynamics of maglev systems with a combined lift and guidance is presented briefly. And, the secondary suspension is analyzed to understand the role of stiffness and damping factors in passive devices. Finally, LQG/LTR mulitivariable control systems are designed for the overall maglev systems with and without secondary suspension, and then the system performances in these two cases are evaluated.

• Korean Management Science Review
• /
• v.25 no.2
• /
• pp.1-12
• /
• 2008

In the ultimatum game two players have to divide a certain amount of money between them. One player is the allocator and proposes a division of the money. The other is the recipient and can either accept or reject the proposed division. If the recipient accepts, the money is divided as proposed. If the recipient rejects, however, both players receive nothing. Purchase decisions could be classified on two basic factors (or dimensions) : involvement and think/feel in the FCB grid model. In this study we studied the influences of the two factors in purchase decisions on the choice of strategy (or propensity to fairness) in the ultimatum game. The empirical study showed that a decision maker chooses rational strategy more frequently when he (or she) is thinkful (or cognitive) in high involvement level.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.12
• /
• pp.61-67
• /
• 2005

This paper presents the carrier phase DGPS method providing a stable navigation solution under the condition of frequent blockage of the GPS signals. The proposed algorithm reject the channels having large errors using a clock bias drift and then calculated the more accurate solution. By investigating the relation between visible satellites` elevation and their clock bias drift, a proper threshold is set. Simulation shows that the presented result is as good as that of commercial system with real data.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.11b
• /
• pp.644-648
• /
• 2002

멀티미디어 서비스를 제공하는 미래의 이동통신 시스템에서는 데이터의 신뢰성 있는 전송을 위해 데이터링크 계층에서 제공하는 프레임 에러율(FER: Frame Error Rates)을 감소시켜야 한다. 이를 위해 라디오링크 프로토콜(RLP: radio link protocol) 계층에서는 ARQ(Automatic Repeat request) 기법을 사용한다. 본 논문에서는 기지국에서 이동 호스트로 전송되는 국부적인 재전송 프레임(Frame)의 순서가 연속된 에러로 인하여 순서가 뒤바뀌고, 이로 인하여 기지국 데이터 링크계층에서 잦은 재전송으로 발생되는 높은 상호지연을 줄이기 위해 개선된 비순서적 재전송 기법을 제안하였다. 제안된 기법은 재전송방법 중 선택적 거절(selective-reject) ARQ의 비순서적 재전송에 수정한 빠른 재전승 기법을 적용하였으며, 기지국과 이동호스트 사이에서 데이터그램(Datagram)의 단편화(fragment)로 인한 링크계층의 Re-Sequencing을 하지 않기 때문에, 종단간 지연된 성능을 향상 시킬 수 있다.