• 한국광학회지
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• 제4권3호
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• pp.301-308
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• 1993

현상론적인 비 선형 이득 포화 효과가 연속 파장 가변시 다전극 DBR 레이저의 변조 특성에 미치는 영향을 이론적으로 분석하였다. 수동 부분에 전류 주입의 증가에 따라 FM 효율, 3dB 대역폭, 공명 주파수는 감소하지만, flat FM응답은 증가한다. 비 선형 이득 포화 효과는 FM/IM응답, 3dB 대역폭, 공명 주파수, chirping-to-modulation-power ratio 등 변조 특성에 커다란 영향을 미치지만, 연속 파장 가변에 의한 변조 특성에는 영향을 미치지 않는다.

• 품질경영학회지
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• 제46권1호
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• pp.39-74
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• 2018

Purpose: For more than 30 years, robust parameter design (RPD), which attempts to minimize the process bias (i.e., deviation between the mean and the target) and its variability simultaneously, has received consistent attention from researchers in academia and industry. Based on Taguchi's philosophy, a number of RPD methodologies have been developed to improve the quality of products and processes. The primary purpose of this paper is to review and discuss existing RPD methodologies in terms of the three sequential RPD procedures of experimental design, parameter estimation, and optimization. Methods: This literature study composes three review aspects including experimental design, estimation modeling, and optimization methods. Results: To analyze the benefits and weaknesses of conventional RPD methods and investigate the requirements of future research, we first analyze a variety of experimental formats associated with input control and noise factors, output responses and replication, and estimation approaches. Secondly, existing estimation methods are categorized according to their implementation of least-squares, maximum likelihood estimation, generalized linear models, Bayesian techniques, or the response surface methodology. Thirdly, optimization models for single and multiple responses problems are analyzed within their historical and functional framework. Conclusion: This study identifies the current RPD foundations and unresolved problems, including ample discussion of further directions of study.

• 산업경영시스템학회지
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• 제25권2호
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• pp.11-18
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• 2002

Psychological and physiological effects of the simulator sickness could be important bias factors for the sensibility evaluation. The purpose of the present study was to clear the differences of psychophysiological responses due to individual sensitivity of simulator sickness. The present experiment tried to investigate the simulator sickness objectively by observing the change of the simulator sickness for the different level of sickness groups (sick and non_sick group). The subjective evaluations using Simulator Sickness Questionnaire (SSQ) and physiological responses were measured every five minutes when they were driving as 60km/h in the driving graphic simulator. Response level of the subjective evaluation for all subjects on the simulator sickness was linearly increased with time for every item, and the response level of sick group was bigger than that of non_sick group. When the analysis on central nervous system was done separately on the sick and the non_sick group, there was significant difference in the parameter $\theta$/total at Fz and Cz. Although the analysis on autonomic nervous system for all subjects showed the increased activation of sympathetic nervous system, there was no significant difference between the sick and non_sick group. In summary, it is necessary to select the subjects who feel less simulator sickness in order to be accurate sensibility evaluation. The parameters to distinguish between the sick and non_sick group were the change on $\theta$/total and subjective evaluation using SSQ.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권3호
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• pp.175-186
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• 2022

This study aimed to systematically review the effectiveness of methylene blue (MB) photosensitizers in the management of symptomatic oral lichen planus (OLP). Electronic online databases and manual searches were performed for randomized controlled trials (RCTs) published in English between January 2010 and February 2022. RCTs comparing photodynamic therapy (PDT) and corticosteroid therapy at baseline and follow-up period were identified. The Cochrane risk of bias tool was used to assess the quality of the included studies. A meta-analysis was performed regarding visual analog scale (VAS) scores, Thongprasom sign scores, lesion size, response to treatment, and exacerbation of lesions after therapy. The clinical severity was analyzed qualitatively. Five RCTs consisting of 180 samples fulfilled the inclusion and exclusion criteria. All parameters of VAS score, Thongprasom sign score, lesion size, and response to treatment were statistically non-significant. Our results indicate that both MB-PDT and corticosteroid therapy are effective for the management of OLP. Moreover, MB-PDT is an effective alternative treatment option for OLP when corticosteroids are contraindicated. However, conclusive evidence cannot be ascertained owing to the heterogeneity among the studies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1305-1308
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• 2003

A new technique is presented to construct a predictive model of plasma etch process. This was accomplished by combining a backpropagation neural network (BPNN) and a genetic algorithm (GA). The predictive model constructed in this way is referred to as a GA-BPNN. The GA played a role of controlling training factors simultaneously. The training factors to be optimized are the hidden neuron, training tolerance, initial weight magnitude, and two gradients of bipolar sigmoid and linear functions. Each etch response was optimized separately. The proposed scheme was evaluated with a set of experimental plasma etch data. The etch process was characterized by a $2^3$ full factorial experiment. The etch responses modeled are aluminum (A1) etch rate, silica profile angle, A1 selectivity, and dc bias. Additional test data were prepared to evaluate model appropriateness. The GA-BPNN was compared to a conventional BPNN. Compared to the BPNN, the GA-BPNN demonstrated an improvement of more than 20% for all etch responses. The improvement was significant in the case of A1 etch rate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1375-1381
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• 2007

In this paper, we propose a linear modeling and identical PD controller design scheme for the three-pole hybrid-type AMB recently developed in the laboratory, which consists of three permanent magnets, providing bias flux, three Hall diodes, measuring rotor displacements, and ring type permanent magnet bearing, stabilizing in axial and tilting directions. Along the three physical coordinates formed by three poles, we introduce the redundant coordinate system and three identical decoupled controllers to construct linear model. The experiments are also carried out in order to verify the effectiveness of proposed controller in stabilizing the transient and steady state response of rotor.

• Near Infrared Analysis
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• 제1권1호
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• pp.9-17
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• 2000

A variety of standardization methods between two near-infrared (NIR) spectrometers were investigated for the prediction of five constituents in trans-alkylation process. Spectra were collected by two different instruments (one is regarded as mater instrument, other on as slave instrument). Three well-known standardization methods of direct standardization (DS), piecewise direct standardization (PDS) and slope/bias correction of response variable were applied to trans-alkylation samples on the slave instrument. We have examined for a set of reliable standardization samples using smaller number of transfer samples in order to increase efficiency of standardization.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1127-1127
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• 2001

The transfer of predictive models using various chemometric techniques has been reported for FTNIR and scanning-grating based NIR instruments with respect relatively dry samples (<10% water). Some of the currently used transfer techniques include slope and bias correction (SBC), direct standardization (DS), piecewise direct standardization (PDS), orthogonal signal correction (OSC), finite impulse transform (FIR) and wavelet transform (WT) and application of neural networks. In a previous study (Greensill et at., 2001) on calibration transfer for wet samples (intact melons) across silicon diode array instrumentation, we reported on the performance of various techniques (SBC, DS, PDS, double window PDS (DWPDS), OSC, FIR, WT, a simple photometric response correction and wavelength interpolative method and a model updating method) in terms of RMSEP and Fearns criterion for comparison of RMSEP. In the current study, we compare these melon transfer results to a similar study employing pairs of spectrometers for non-invasive prediction of soluble solid content of peaches.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.45-46
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• 2008

The conventional biased vertical alignment (BVA) mode has several advantages such as rubbing- and protrusion-free, wide-viewing angle and stable LC dynamics against external pressure. However manufacturing process of BVA mode is difficult task because the pixel and bias electrode signal are different in each frame. To solve this problem, we investigated the pattern free vertical alignment (PFVA) by using the UV-curable reactive mesogen (RM), in which the LC molecules were made to be pre-tilted. Eventually transmittance and response time in PFVA mode were found to be improved as compared to BVA mode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.100-102
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• 2007

In this paper, a modified multi-level convert for low cost high speed switched reluctance (SR) drive is proposed The proposed multi-level converter has reduced number of power switches and diodes than that of a conventional asymmetric converter for SRM, and lower voltage rating of the dump capacitor comparing with energy efficient c-dump converter. It can supply five operating modes that is boosted, DC-link, zero, negative bias and negative boosted voltage. The proposed multi-level converter has fast excitation and demagnetization modes of phase current, so dynamic response can be achieved. The proposed multi-level converter is verified by computer simulation and experimental results.