• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.318-324
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• 2013

For blind channel equalization, the reliability of signal estimate determines the convergence speed and steady-state performance of the equalizer. Therefore the nonlinear estimator and reference signal being used in signal estimate should be chosen appropriately. In this paper, to increase the reliability of the signal estimate, two errors were obtained by applying coarse signal points and dense signal points respectively to signal estimate, the relative reliabilities of two errors were calculated, then the equalizer was adapted deferentially utilizing the reliabilities. At this point, by applying two errors alternately, two modes of operation were smoothly combined. Through computer simulations the proposed method was confirmed to achieve fast transient state convergence and low steady-state error compared to traditional methods.

• Journal of Korea Multimedia Society
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• v.16 no.3
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• pp.336-341
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• 2013

Reliability analysis for various forms of data obtained from complicated electronic circuits is a necessary process for guaranteeing reliability of the system. Reliability assessment of a system starts from the estimation of failure function. A system can be composed of one item, but in most cases, several items are correlated to each other in one system. This study suggests an estimation method of failure function and reliabilities for infrequent failure events, by considering different form of data obtained from different systems. Estimates of failure function and reliabilities for complex systems composed of two or more items in parallel or in mixed connections can be done by further application of proposed method.

• Journal of the Korean Institute of Gas
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• v.7 no.4 s.21
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• pp.20-23
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• 2003

The analysis of reliabilities of process facilities often uses models based on the Weibull distribution. The parameters in these models are functions of operating conditions, and determined by experiments. Using these values, we calculate the reliability, mean time to failure, and standard deviation. The conventional method assumes that the operating condition is constant, and thus treats the model parameters as constants. In this paper, a reliability function is proposed which is applicable when the scale parameter is a function of time, and an analysis method based on this is also presented. A case study on a cooling fan resulted in a big difference from the conventional method to which the average operating conditions were applied. The proposed method is also applicable to other process facilities, and expected to effectively take into account the effects of changes in the operating conditions on the reliabilities of the facilities.

• Investigative Magnetic Resonance Imaging
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• v.19 no.2
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• pp.88-98
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• 2015

Purpose: To compare the interobserver and intraobserver reliability of mean apparent diffusion coefficient (ADC) values using contrast-enhanced (CE) T1 weighted image (WI) and T2WI as structural images between manual and semiautomatic segmentation methods. Materials and Methods: Between January 2011 and May 2013, 28 patients who underwent brain MR with diffusion weighted image (DWI) and were pathologically confirmed as having glioblastoma participated in our study. The ADC values were measured twice in manual and semiautomatic segmentation methods using CE-T1WI and T2WI as structural images to obtain interobserver and intraobserver reliability. Moreover, intraobserver reliabilities of the different segmentation methods were assessed after subgrouping of the patients based on the MR findings. Results: Interobserver and intraobserver reliabilities were high in both manual and semiautomatic segmentation methods on CE-T1WI-based evaluation, while interobserver reliability on T2WI-based evaluation was not high enough to be used in a clinical context. The intraobserver reliability was particularly lower with the T2WI-based semiautomatic segmentation method in the subgroups with involved $lobes{\leq}2$, with partially demarcated tumor borders, poorly demarcated inner margins of the necrotic portion, and with perilesional edema. Conclusion: Both the manual and semiautomatic segmentation methods on CE-T1WI-based evaluation were clinically acceptable in the measurement of mean ADC values with high interobserver and intraobserver reliabilities.

• Smart Structures and Systems
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• v.14 no.2
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• pp.209-224
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• 2014

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy.

• Journal of Korean Society for Quality Management
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• v.22 no.4
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• pp.152-159
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• 1994

A study of improvement of printing accuracy of special PCB has been carried out by applying the corrected data of laminate dimensional variation to real products. The result of this study improved the accuracy of product by decreasing the deviation between design specifications and end products. This paper will be useful when PCB manufacturers using paper phenol laminates make preparation for customer's needs, more complicated specifications. And so, it will be successful for image renovation of any company by assuring the reliabilities to customers.

• Journal of the Korean Operations Research and Management Science Society
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• v.10 no.2
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• pp.38-44
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• 1985

Systems reliability can be improved by using redundancy and/or developing more reliable components. This papaer considers a joint optimization of both alternatives for a series system. It is shown that the n-stage optimization problem can be decomposed into n single stage subproblem. Each subproblem is further transformed into a univariate optimization problem for which a simple and efficient solution method is developed.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.824-829
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• 1998

In regard to the very stringent-going requirements applied to power supply systems is nowadays applications, the reliability of typical UPS redundency systems are investigated. Several resonable assumptions are made to build up the probability models. The reliabilities of the typical UPS redundency systems are analysed. Their relating Relaibility and MTTF (Mean Time To Faults) are evaluated. It is resulted in that the MTTF of today's UPS redundency systems is unlikely to be beyond 1,000,000 hours.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.501-504
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• 2002

오늘날 어떠한 복잡한 기기에 있어서도 S/W 의 신뢰도는 중요한 요소가 리고 있다. S/W 신뢰도는 보통 NHPP와 같은 신뢰도모델에 의해서 평가한다. S/W 시스템은 테스트 단계예서 품질이 향상되고 운영단계에서는 거의 변화가 없다. 신뢰도를 테스트 단계에서 추정할 것인가 아니면 운영단계에서 추징할 것인가의 여부에 따라서 그 추정방법이 달라져야 한다. 본 논문에서는 두 가지의 상이한 신뢰도개념 즉 운영신뢰도와 테스트 신뢰도를 명확히 구분하여 자세히 고찰한다. 이러한 개념은 기존의 여러 문헌에서 혼용해 사용하거나 잘못사용되어 왔다. 상이한 신뢰도개념을 사용하면 상이한 신뢰도를 얻게 되며, 추후 상이한 신뢰도기준 결정기법에 이르게 된다.

• Journal of the Ergonomics Society of Korea
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• v.30 no.2
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• pp.311-317
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• 2011

Objective: The present study was intended to identify (1) the intra- and inter-rater reliabilities of a visual sensibility evaluation protocol and (2) the effects of NaCOC color and scouring method on the visual sensibility of NaCOC. Thirty female participants(20s & 30s) were participated in the visual sensibility evaluation of NaCOC. Background: Interests in naturally colored organic cotton(NaCOC) increase rapidly in parallel with the social trend of eco-friendly living and wellbeing. Method: Three color sets (ivory, green, and coyote-brown) of NaCOC specimens including one untreated and four treated specimens($Na_2CO_3$; NaOH; enzyme; boiling water) were examined in the study. The visual sensibility evaluation was conducted by the test-retest method using nine pairs of bipolar visual sensibility adjectives(bright-dark; clear-murky; heavy-light; vivid-subdued; warm-cool; fresh-stale; strong-weak; showy-plain; and luxurious-cheap). Results: As a result of reliability of a visual sensibility evaluation protocol, inter-rater variability(average SD=1.06) of visual sensibility evaluation was more than 1.4 times the intra-rater variability(average SD=0.74). However, both the sensibility evaluation reliabilities did not show any systematic pattern of changes. Lastly, ANOVA and post-hoc analysis showed that preferred scouring methods for a visual sensibility adjective pair significantly vary depending on NaCOC color. Application: Both the reliability of visual sensibility evaluation protocol and the analysis of proper scoring method of NaCOC in the study would be useful information to design the affective textile.