• 제목/요약/키워드: Non-linear correlation

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상수도 금속관의 외면과 내면 부식속도 평가에 관한 연구 (Assessment of External and Internal Corrosion Growth Rate for Metallic Water Pipes)

  • 배철호;김주환;김정현;홍성호
    • 한국지반환경공학회 논문집
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    • 제9권1호
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    • pp.17-25
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    • 2008
  • 본 연구에서는 상수도 금속관의 관 내 외면 부식상태를 평가하고, 내 외면 부식깊이(속도)와 매설년수의 관계를 통하여 내 외면 공식성장속도, 그리고 국내의 토양특성 인자들이 관 외면부식에 미치는 영향을 평가하여 관 외면의 노후상태를 예측할 수 있는 부식속도 모델을 제안하였다. 수집된 관체의 외면 부식깊이는 평균적으로 1.38 mm, 내면은 2.13 mm이었고, 이는 수질 등 내면부식영향 인자가 토양 등 외면부식영향 인자보다 부식에 미치는 영향이 크기 때문이며, 평균 공식성장 속도도 내면이 외면보다 두 배정도 빠른 것으로 나타났다. 외면부식에 영향을 주는 각 토양과 외면부식속도와의 상관성은 높지 않았으나, 모든 토양항목을 포함하여 회귀분석을 통하여 수립된 외면부식속도 예측모델은 기존 모델과 비교하여 더 높은 상관성을 보였다.

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음성 신호 분류에 따른 장애 음성의 변동률 분석, 비선형 동적 분석, 캡스트럼 분석의 유용성 (The Utility of Perturbation, Non-linear dynamic, and Cepstrum measures of dysphonia according to Signal Typing)

  • 최성희;최철희
    • 말소리와 음성과학
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    • 제6권3호
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    • pp.63-72
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    • 2014
  • The current study assessed the utility of acoustic analyses the most commonly used in routine clinical voice assessment including perturbation, nonlinear dynamic analysis, and Spectral/Cepstrum analysis based on signal typing of dysphonic voices and investigated their applicability of clinical acoustic analysis methods. A total of 70 dysphonic voice samples were classified with signal typing using narrowband spectrogram. Traditional parameters of %jitter, %shimmer, and signal-to-noise ratio were calculated for the signals using TF32 and correlation dimension(D2) of nonlinear dynamic parameter and spectral/cepstral measures including mean CPP, CPP_sd, CPPf0, CPPf0_sd, L/H ratio, and L/H ratio_sd were also calculated with ADSV(Analysis of Dysphonia in Speech and VoiceTM). Auditory perceptual analysis was performed by two blinded speech-language pathologists with GRBAS. The results showed that nearly periodic Type 1 signals were all functional dysphonia and Type 4 signals were comprised of neurogenic and organic voice disorders. Only Type 1 voice signals were reliable for perturbation analysis in this study. Significant signal typing-related differences were found in all acoustic and auditory-perceptual measures. SNR, CPP, L/H ratio values for Type 4 were significantly lower than those of other voice signals and significant higher %jitter, %shimmer were observed in Type 4 voice signals(p<.001). Additionally, with increase of signal type, D2 values significantly increased and more complex and nonlinear patterns were represented. Nevertheless, voice signals with highly noise component associated with breathiness were not able to obtain D2. In particular, CPP, was highly sensitive with voice quality 'G', 'R', 'B' than any other acoustic measures. Thus, Spectral and cepstral analyses may be applied for more severe dysphonic voices such as Type 4 signals and CPP can be more accurate and predictive acoustic marker in measuring voice quality and severity in dysphonia.

RMR과 전기비저항의 상관성 해석에 기초하여 지시크리깅을 적용한 최적 암반 분류 기법 고찰 (Investigation of Indicator Kriging for Evaluating Proper Rock Mass Classification based on Electrical Resistivity and RMR Correlation Analysis)

  • 이경주;하희상;고광범;김지수
    • 터널과지하공간
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    • 제19권5호
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    • pp.407-420
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    • 2009
  • 이 연구에서는 시추 조사와 물리탐사 자료와 같은 다양한 지반 정보를 통합하여 최적의 암반 분류 기법을 도출하는데 지시크리깅을 적용하였다. 최적의 지시크리깅 결과를 얻기 위해서는 효과적으로 hard data(시추조사)와 soft data(물리탐사 자료)를 통합하기 위한 알맞은 방법을 모색할 필요가 있다. 이론적인 베리오그램 모델변수를 결정하기 위해 반복적 비선형 역산 방법을 적용하였고 이 알고리즘의 타당성 검증을 위해 목적함수의 분포양상을 검토한 결과 상관거리에 따른 구배는 대단히 작은 특성을 보였다. 현장 적용지역은 지표에서 터널 계획고까지의 심도가 최대 500 m인 대규모 산악터널 예정지이다. 지시크리깅을 이용하여 soft data인 AMT (Audio frequency Magneto-Telluric) 탐사 자료와 hard data인 RMR자료를 하나로 통합하고자 하였다. 결론적으로 터널계획고와 터널 상부 1D 구간에 대한 암반등급도를 작성하여 도시하였다.

일부 지역 주민들의 스트레스 관련요인에 대한 연구 (Community Based Study for Stress and It's Related Factors)

  • 이정미;길상선;권근상;오경재
    • Journal of Preventive Medicine and Public Health
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    • 제36권2호
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    • pp.125-130
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    • 2003
  • Objectives : This study evaluated the stress of community residents using the General Health Questionnaire, GHQ-60, as an instrument of stress measurement. Methods : The study included 2100 residents, aged 20 and over, living in three areas, a large city, a medium sized city and a rural area, between June and September 2001. A questionnaire interviewing method was used to collect data. The data were analyzed using a t-test, ANOVA, Pearson's correlation coefficients and multiple regression analysis. Results : In this study, the degree of stress, as measured by the GHQ-60, was shown to be significantly higher in the following categories: females, people over 60 years old, people engaged in the primary industries and labor work, low incomes, the divorced and the bereaved, people who received no more than an elementary education, people who suffer from chronic diseases and non-exercisers. A factor analysis suggested that there were three factors of social dysfunction factors; psychosomatic symptom, and depression and anxiety, The social dysfunction factors was statistically significant for the groups described above. The factor of psychosomatic symptoms was statistically significant in the rural residents, and in the groups describedabove. The depression and anxiety factor was statistically significant in the large city residents, people aged between 20-29 years, students, unmarried persons, university graduates and those having suffered from chronic diseases. From the multiple linear regression analyses, chronic disease, exercise, gender and income, proved to be significant stress related factors Conclusions : This study suggests that special attention should be given to the management of the chronic invalided, non-exercisers, females and snail income earners, in order to maintain and promote the psychological health of residents in a community.

고차평균법에 의한 난류구조의 규명 및 난류모델의 개발 (Investigation of Turbulence Structures and Development Turbulence Model Based upon a Higher Order Averaging Method)

  • 여운광;편종근
    • 한국해안해양공학회지
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    • 제4권4호
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    • pp.201-207
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    • 1992
  • Yeo(1987)에 의하여 유도된 평균된 비선형괴의 표현식을 이론 및 실험적 분석을 통하여 난류구조의 특성을 밝혔다. 일반 평균정의식으로부터 가우스형 필터함수를 사용하여 얻어진 이 식에 의하면 종래와 같이 비선형항을 4개의 항으로 분리하여 각각을 해석할 필요가 없으며 기존 난류모형이 갖는 Closure문제로 인한 한계성도 극복할 수 있는 가능공을 보여주고 있다. 새로이 유도된 표현식으로부터 종래 개염적으로만 인식되어 왔던 vortex stretching현상을 이논적으로 도출할 수 있었으며 실제 난류자료의 분석결업 이들의 영향이 지배적임을 입증하였다. 따라서 vortex stretching의 영향을 무시한 난류모형은 그 타당성을 상설하게 된다. 또한 LES모형에 적용시킨 결과 일반적 형태의 에너지 표현식을 얻을 수 있었으며 기존의 Smagorinsky모형, 회전모형및 SGS에너지 모형은 완전히 별개의 것이 아니라 난류에너지 중 변형 및 회전에 의한 영향의 고려 가부에 따라 구분되어짐을 보였다.

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RCP 시나리오에 따른 비관개기 누적강수량을 고려한 둑높이기 저수지의 미래 가뭄대응능력 평가 (Evaluation of Reservoir Drought Response Capability Considering Precipitation of Non-irrigation Period using RCP Scenario)

  • 방재홍;이상현;최진용;이성학
    • 한국농공학회논문집
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    • 제59권1호
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    • pp.31-43
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    • 2017
  • Recent studies about irrigation water use have focused on agricultural reservoir operation in irrigation period. At the same time, it is significant to store water resource in reservoir during non-irrigation period in order to secure sufficient water in early growing season. In this study, Representative Concentration Pathways (RCP) 4.5, 8.5 scenarios with the Global Climate Model (GCM) of The Second Generation Earth System Model (CanESM2) were downscaled with bias correlation method. Cumulative precipitation during non-irrigation season, October to March, was analyzed. Interaction between cumulative precipitation and carry-over storage was analyzed with linear regression model for ten study reservoirs. Using the regression model, reservoir drought response ability was evaluated with expression of excess and deficiency. The results showed that future droughts will be more severe than past droughts. Especially in case of non-exceedance probability of 10%, drought in southern region seemed to be serious. Nine study reservoirs showed deficiency range from 10% to 55%, which turned out to be vulnerable for future drought. Only Jang-Chan reservoir was secure for early growing season in spite of drought with deficiency of 8% and -2%. The results of this study represents current agricultural reservoirs have vulnerability for the upcoming drought.

Compositional differences of Bojungikgi-tang decoctions using pressurized or non-pressurized extraction methods with variable extraction times

  • Kim, Jung-Hoon;Seo, Chang-Seob;Kim, Seong-Sil;Shin, Hyeun-Kyoo
    • 대한본초학회지
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    • 제28권4호
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    • pp.1-6
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    • 2013
  • Objectives : In other to determine the optimal extraction conditions, the various Bojungikgi-tang (BJIGT) decoctions prepared by different pressure levels and different extraction times were compared and evaluated in terms of the extract yield and the total soluble solid content. Methods : Decoctions were prepared by the pressure levels of 0 (non-pressurized) and 1 $kgf/cm^2$ (pressurized) for 60, 120 and 180 min. The extract yield and the total soluble solids content of decoctions were measured, and the amounts of the reference compounds in decoctions were investigated by the analysis using high performance liquid chromatography. Results : The extract yield and the total soluble solid content were higher in decoctions extracted by the pressurized method than those from decoction with non-pressurized method. The patterns of yield and contents showed a proportional increase to the extraction time. In analysis of the linear regression for four reference compounds such as liquiritin, nodakenin, hesperidin, and glycyrrhizin, the good linearity with the correlation coefficient more than 0.9999 was observed. The highest contents for four reference compounds were observed at 180 min of both the pressurized method and the non-pressurized method. Conclusions : This study suggests that the pressure in extraction method and the extraction time affect the compositional constituents in BJIGT decoctions. The extraction time of 180 min could be chosen in both pressurized and non-pressurized method as optimal extraction condition.

적혈구중 크롬농도를 이용한 6가크롬 노출의 생물학적 지표 (Chromium in Erythrocytes as a Biological Marker of Worker Exposed to Hexavalent Chromium)

  • 윤의성;김광종
    • 한국산업보건학회지
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    • 제10권1호
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    • pp.223-234
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    • 2000
  • Objective - To evaluate the usefulness of chromium in erythrocytes as a biological marker of exposure to hexavalent chromium in chromate producers and chrome platers Methods - Blood and urine samples were ramdomly obtained from chromate producers (n=34) and chrome platers (n=35), and non-exposed workers (n=75), chromium level in erythrocytes and plasma, and urine were measured. Different chromium exposure workers were assessed through measurements of airborne hexavalent chromium concentrations using a personal air sampler. Linear associations between variables were evaluated with correlation analysis. Results - The chromate producers had mean chromium levels in erythrocytes five fold as higher than the chrome platers, and fifteen fold higher than non-exposed group. Among the chromium exposed workers, airborne hexavalent chromium was positively and strongly correlated with in erythrocytes (r=0.689, p<0.01), and erythrocytes chromium was inversely correlated with hematocrit (r=-0.441, p<0.01), hemoglobin (r=-0.465, p<0.01) and the number of red blood cells (r=-0.28, p<0.05). Conclusions - In conclusion, this study suggests that chromium in erythrocytes is a good indicator of the chromium body burden caused by exposure to hexavalent chromium.

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직선 고속 주행시 운전자의 뇌파가 프랙탈 차원에 미치는 영향: 카오스 이론을 중심으로 (Effects on Fractal Dimension by Automobile Driver's EEG during Highway Driving : Based on Chaos Theory)

  • 이돈규;김정룡
    • 산업경영시스템학회지
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    • 제23권57호
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    • pp.51-62
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    • 2000
  • In this study, the psycho-physiological response of drivers was investigated in terms of EEG(Electroencephalogram), especially with the fractal dimensions computed by Chaotic algorithm. The Chaotic algorithm Is well Known to sensitively analyze the non-linear information such as brain waves. An automobile with a fully equipped data acquisition system was used to collect the data. Ten healthy subjects participated in the experiment. EEG data were collected while subjects were driving the car between Won-ju and Shin-gal J.C. on Young-Dong highway The results were presented in terms of 3-Dimensional attractor to confirm the chaotic nature of the EEG data. The correlation dimension and fractal dimension were calculated to evaluate the complexity of the brain activity as the driving duration changes. In particular, the fractal dimension indicated a difference between the driving condition and non-driving condition while other spectral variables showed inconsistent results. Based upon the fractal dimension, drivers processed the most information at the beginning of the highway driving and the amount of brain activity gradually decreased and stabilized. No particular decrease of brain activity was observed even after 100 km driving. Considering the sensitivity and consistency of the analysis by Chaotic algorithm, the fractal dimension can be a useful parameter to evaluate the psycho-physiological responses of human brain at various driving conditions.

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Neuro-Fuzzy System for Predicting Optimal Weld Parameters of Horizontal Fillet welds

  • Moon, H.S.;Na, S.J.
    • International Journal of Korean Welding Society
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    • 제1권2호
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    • pp.36-44
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    • 2001
  • To get the appropriate welding process variables, mathematical modeling in conjunction with many experiments is necessary to predict the magnitude of weld bead shape. Even though the experimental results are reliable, it has a difficulty in accurately predicting welding process variables for the desired weld bead shape because of nonlinear and complex characteristics of welding processes. The welding condition determined for the desired weld bead shape may cause the weld defect if the welding current/voltage/speed combination is improperly selected. In this study, the $2^{n-1}$ fractional factorial design method and correlation parameter were used to investigate the effect of the welding process variables on the fillet joint shape, and the multiple non-linear regression analysis was used for modeling the gas metal arc welding(GMAW)parameters of the fillet joint. Finally, a fuzzy rule-based method and a neural network method were proposed so that the complexity and non-linearity of arc welding phenomena could be effectively overcome. The performance of the proposed neuro-fuzzy system was evaluated through various experiments. The experimental results showed that the proposed neuro-fuzzy system could effectively check the welding conditions as to whether or not weld defects would occur, and also adjust the welding conditions to avoid these weld defects.

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