• International Journal of Automotive Technology
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• v.6 no.3
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• pp.235-242
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• 2005

This study introduces the Reliability-Based Design Optimization (RBDO) to enhance the kinematic and compliance (K & C) characteristics of automotive suspension system. In previous studies, the deterministic optimization has been performed to enhance the K & C characteristics. Unfortunately, uncertainties in the real world have not been considered in the deterministic optimization. In the design of suspension system, design variables with the uncertainties, such as the bushing stiffness, have a great influence on the variation of the suspension performances. There is a need to quantify these uncertainties and to apply the RBDO to obtain the design, satisfying the target reliability level. In this research, design variables including uncertainties are dealt as random variables and reliability of the suspension performances, which are related the K & C characteristics, are quantified and the RBDO is performed. The RBD-optimum is compared with the deterministic optimum to verify the enhancement in reliability. Thus, the reliability of the suspension performances is estimated and the RBD-optimum, satisfying the target reliability level, is determined.

• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.95-103
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• 2013

Nonparametric procedure in randomized block design (RBD) was proposed by Friedman (1937) for general alternatives. Also Page (1963) suggested the test for ordered alternatives in RBD. In this paper, we proposed the new nonparametric method in randomized block design using aligned method suggested by Hodges and Lehmann (1962) and the joint placement described in Chung and Kim (2007). Also, Monte Carlo simulation study was adapted to compare the power of the proposed procedure with those of previous procedure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3685-3691
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• 2015

We developed the platform safety step system for the passenger to avoid misstep accident and secure the pedestrian safety. In this study, we classify platform safety step system into hierarchy system and predict the failure rate of each part and calculate the failure rate & MTBF(Mean Time Between Failure) of each module(sub-system) by means of RBD(Reliability Block Diagram) & FTA(Fault Tree Analysis). Finally, we will propose the reliability analysis results for RAMS analysis of platform safety step system.

• The Journal of the Acoustical Society of Korea
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• v.35 no.5
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• pp.331-339
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• 2016

This paper suggests an estimation method of the source signal and the channel impulse response (CIR) using ray-based blind deconvolution (RBD) in the underwater acoustic channel environment where Doppler effect exists by the relative motion between source and receiver. It is difficult to estimate the CIR on Doppler effect by the matched filter with a highly Doppler-sensitive waveform such as the m-sequence signal because Doppler shift can severely degrade the correlation between the received signal corrupted by Doppler effect and the original source signal. In this study, the Doppler-shifted source-signal's phase is estimated using the RBD, and the received signal is compensated by it to obtain the Doppler-corrected CIR. It is verified that using the matched filter with the received signal from the experimental data fails to estimate the CIR while the obtained CIR by the suggested method has the similarity to the propagation path of the ray model. Also, the results show that the reconstructed source signal using the RBD has the better Doppler shift compensation than the Doppler-shifted source signal derived from scattering function.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.427-434
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• 2000

본 연구에서는 품질기능전개(QFD)를 품질전개, 기술전개, 원가전개, 신뢰성전개로 구분하여 각 단계에서 실무적으로 고려해야 할 중요한 사항을 제안한다. 품질전개에서는VOC로 J.D.Power사의 시장품질조사 방법을 활용할 것을 제안하며 기술전개에서는 새로운 SPC 공정도와 작업표준 작성방안을 제안한다. 끝으로 신뢰성 전개에서는 BOM의 구조분석과 RBD, FTA 통합기능분석, FMEA의 체계적인 정리 등의 3단계 전개방안을 제안한다.

• Journal of the Korea Safety Management & Science
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• v.7 no.4
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• pp.219-227
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• 2005

Three general algorithms for evaluating the reliability for complex bridge system are proposed. These methods, such as Keystone, Boolean, Network algorithms are powerful and effective to derive an reliability expression for many practical complex systems. The combination approach of RBD and FTA proposed in this paper provides an effective way to evaluate the functional dependency for applications of FMEA.

• Journal of the Korea Society for Simulation
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• v.22 no.4
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• pp.109-118
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• 2013

This paper adopts the system configuration to assess the reliability instead of making a fault tree (FT), which is a traditional method to analyze reliability of a certain system; this is the reliability block diagram (RBD) method. The RBD method is a graphical presentation of a system diagram connecting the subsystems of components according to their functions or reliability relationships. The equipment model for the reliability simulation is modeled based on the discrete event system specification (DEVS) formalism. In order to make various alternatives of target system, this paper also adopts the system entity structure (SES), an ontological framework that hierarchically represents the elements of a system and their relationships. To enhance the calculation time of reliability analysis, GPU-based accelerations are adopted to the reliability simulation.

• The Journal of the Acoustical Society of Korea
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• v.36 no.6
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• pp.378-386
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• 2017

Accurate distance measurement between maneuver target in underwater and measuring devices is required to perform quantitative test evaluation in marine weapons system R&D process. In general, the target distance is measured using a one-way ToA (Time of Arrival) method that calculates the time difference between transmitted and received signals from the two accurately synchronized devices. However, the distance estimation performance is degraded because of the multi-path environments. In this paper, the time-variant transfer function of complex underwater environment is estimated from each received data frame using RBD (Ray-based Blind Deconvolution), and the estimated time-variant transfer function is then used to get rid of the effect about complex underwater environment and to recover the data signal using PTRM (Passive Time Reversal Mirror). The result from the simulation and experimental data show that the suggested method improve the distance estimation performance when comparing with the conventional ToA method.

• Annals of Clinical Neurophysiology
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• v.17 no.1
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• pp.17-23
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• 2015

Background: Sleep-related disturbances and sleep disorders are common in Parkinson's disease (PD) and have a great impact on daily life of PD patients. This study was done to find the sleep characteristics and sleep disturbing factors in PD patients according to disease severity through clinical interview and polysomnographic (PSG) study. Methods: Fifty patients with PD (22 males, age $60.6{\pm}6.4$, Hoehn and Yahr (HY) stage $2.7{\pm}1.0$) were recruited and thoroughly interviewed about their sleep. PSG was performed on the patients taking routine antiparkinsonian medications. Patients were grouped into mild and moderate/severe group according to HY stage, and the results were compared between each group. Results: Ninety-four percent of total patients had one or more sleep-related disturbances based on the interview or PSG. On interview, the moderate/severe group complained more insomnia and REM sleep behavior disorder (RBD) than mild group. In PSG findings, the moderate/severe group showed lower sleep efficiency, longer sleep latency, REM sleep latency, waking time after sleep onset, and higher prevalence of RBD. Conclusions: In this study, most patients with PD had sleep disturbances. Clinical interview and PSG findings revealed deterioration of sleep quality along the disease severity. Our results suggest that sleep disturbances in PD patients are prevalent and warrant clinical attention, especially to the patients with advanced disease.

• The Journal of the Acoustical Society of Korea
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• v.35 no.5
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• pp.375-382
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• 2016

This paper presents the results for the performance improvement of underwater communication in a passive time reversal mirror (PTRM) using ray-based blind deconvolution (RBD). In conventional PTRM, the signal to be recovered is found from matched-filtering the received probe signal. However, the communication performance is degraded because the time-varying impulse response for each data frame is not reflected in the received probe signal. In this study, the time-variant transfer function is estimated from each received data frame using RBD, and the estimated time-variant transfer function is then used to recover the data signal using PTRM. The results from the experimental data show that the suggested method improves the communication performance when comparing with the conventional PTRM.