• 제목/요약/키워드: bias degree

검색결과 148건 처리시간 0.026초

복잡한 도로 상태의 동적 비선형 제어를 위한 학습 신경망 (A Dynamic Neural Networks for Nonlinear Control at Complicated Road Situations)

  • 김종만;신동용;김원섭;김성중
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 D
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    • pp.2949-2952
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    • 2000
  • A new neural networks and learning algorithm are proposed in order to measure nonlinear heights of complexed road environments in realtime without pre-information. This new neural networks is Error Self Recurrent Neural Networks(ESRN), The structure of it is similar to recurrent neural networks: a delayed output as the input and a delayed error between the output of plant and neural networks as a bias input. In addition, we compute the desired value of hidden layer by an optimal method instead of transfering desired values by back-propagation and each weights are updated by RLS(Recursive Least Square). Consequently. this neural networks are not sensitive to initial weights and a learning rate, and have a faster convergence rate than conventional neural networks. We can estimate nonlinear models in realtime by ESRN and learning algorithm and control nonlinear models. To show the performance of this one. we control 7 degree of freedom full car model with several control method. From this simulation. this estimation and controller were proved to be effective to the measurements of nonlinear road environment systems.

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Production of Fine-resolution Agrometeorological Data Using Climate Model

  • Ahn, Joong-Bae;Shim, Kyo-Moon;Lee, Deog-Bae;Kang, Su-Chul;Hur, Jina
    • 한국농림기상학회:학술대회논문집
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    • 한국농림기상학회 2011년도 학술발표회
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    • pp.20-27
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    • 2011
  • A system for fine-resolution long-range weather forecast is introduced in this study. The system is basically consisted of a global-scale coupled general circulation model (CGCM) and Weather Research and Forecast (WRF) regional model. The system makes use of a data assimilation method in order to reduce the initial shock or drift that occurs at the beginning of coupling due to imbalance between model dynamics and observed initial condition. The long-range predictions are produced in the system based on a non-linear ensemble method. At the same time, the model bias are eliminated by estimating the difference between hindcast model climate and observation. In this research, the predictability of the forecast system is studied, and it is illustrated that the system can be effectively used for the high resolution long-term weather prediction. Also, using the system, fine-resolution climatological data has been produced with high degree of accuracy. It is proved that the production of agrometeorological variables that are not intensively observed are also possible.

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류마티스 관절염 백서 모델에서 작약감초부자탕의 효과: 체계적 문헌고찰 및 메타분석 (Effects of Jakyakkamchobuja-tang on Rheumatoid Arthritis in Rat Model: Systemic Review and Meta-Analysis)

  • 김채연;이상현;황만석
    • 한방재활의학과학회지
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    • 제33권3호
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    • pp.79-96
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    • 2023
  • Objectives This study was designed to review the effect of Jakyakkamchobuja-tang on rat model with rheumatoid arthritis. Methods We used seven databases (PubMed, EMBASE, Cochrane CENTRAL, China National Knowledge Infrastructure, Oriental Medicine Advanced Searching Integrated System, Korean studies Information Service System, National Digital Science Library) from their inception to May 2023 without language restrictions. Systematic Review Centre for Laboratory Animal Experimentation's tool was used to evaluate the risk of bias. RevMan software (V5.4) was used for the meta-analysis. Results Five studies were selected following our inclusion criteria. The arthritis index decreased significantly (standardized mean difference=-2.06; 95% confidence interval=-3.07 to -1.04; p<0.0001) in Jakyakkamchobuja-tang group. Also, serum cytokines in serum and paw swelling degree decreased in Jakyakkamchobuja-tang group. Conclusions Jakyakkamchobuja-tang may be effective in treating rheumatoid arthritis. Although there is a limitation that the design of drug dosage varies between papers, it can be expected to be applied as an alternative to Western medicine, and it is believed to contribute to the standardization of herbal treatment for rheumatoid arthritis.

1급 응급구조사의 임파워먼트와 비판적 사고성향에 관한 연구 (A Study on Empowerment and Critical Thinking of the 1st Emergency Medical Technician)

  • 박대성;김은주
    • 한국응급구조학회지
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    • 제10권3호
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    • pp.5-20
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    • 2006
  • Purpose: This study examines the degree of empowerment recognized by the 1st paramedics and the trend of their critical thinking, analyzes correlations between empowerment and critical thinking to reveal whether there is statistically significant difference between them and then is to provide basic materials necessary for research on empowerment and critical thinking. Method: This study distributes 105 structured self-report questionnaires to the 1st emergency medical technicians working at fire fighting police boxes, general hospitals, clinics and emergency medical information centers in G Metropolitan City and J province from April 29 to May 28, 2006, collects their responses directly and analyzes results with t-test, F-test(ANOVA) and Pearson's Correlation Coefficient. Result: 1. First, average score of empowerment of subjects was 4.68 out of 6 and according to scores by area, capacity 5.98 was highest, followed by significance 5.41, self- determination 4.44 and effectiveness 3.79. 2. degree of empowerment according to general characteristics of subjects showed statistically significant differences in final education(F=2.714, p= .049), level of salary (F=3.298, p= .014) and satisfaction of current job (F=5.399, p= .001). 3. average score of critical thinking of subjects was 3.28 out of 7 and according to areas, no bias 3.95 was highest, followed by maturity 3.68, structure 3.35, inquisitiveness 3.11, pursuit of truth 3.07, critical thinking and self-confidence 3.00, analyticity 2.98. 4. degree of critical thinking by general characteristics of subjects showed statistically significant differences in age(F=2.577, p= .041), final education (F=7.877, p= .000), current workplace (F=3.513, p= .018), level of salary(F=4.628, p= .002), satisfaction with current job(F=6.879, p= .000) and intention to transfer current job(t=15.21, p=.000). 5. as a result of correlations between empowerment and critical thinking of subjects, Pearson correlation coefficients between whole empowerment and critical thinking were r= .21, p=.013. Conclusion: It is considered that the 1st paramedic managers must seek how to keep and manage empowerment and development of education and training program which can enhance critical thinking is needed. Further, emergency educators must develop educational program based on the concept of empowerment to establish early awareness of a desirable organization culture and increase understanding of empowerment in the process of education.

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자장여과 아크 소스에서 각 전자석이 플라즈마 인출에 미치는 영향 (The effects of solenoid magnet on plasma extraction in Filtered Vacuum Arc Source (FVAS))

  • 김종국;변응선;이구현;조영상
    • 한국진공학회지
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    • 제10권4호
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    • pp.431-439
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    • 2001
  • 비정질 다이아몬드 박막(amorphous-Diamond a-B)을 증착하기 위하여 제작된 Filtered Vacuum Arc Source (FVAS)는 60도의 굽힘 각도를 가지는 토러스형 구조로 토러스 반경 266 mm, 플라즈마 덕트 반경 80 % 전체 길이 600 mm이며, 1 개의 영구자석 및 5 개의 전자석으로 되어있다. 플라즈마 덕트는 임의의 전압을 인가할 수 있도록 전기적으로 절연 시켰으며, 덕트 내부는 배플을 설치하여 macro-particle의 되튐 현상을 방지하였다. 사용된 음극은 직경 80 mm의 graphite이다. 각 전자석이 플라즈마 인출에 미치는 영향은 taguchi 실험계획법을 이용, 수치 모사와 실험을 행하였다. 소스 전자석과 인출 전자석은 아크의 안정성에 영향을 주었고, 빔 인출 전류는 낮은 소스 전자석 전류와 특정한 필터 전자석 전류에서 최대값을 나타내었다. 이때 소스, 인출, 굽힘, 반사, 출구 전자석의 전류값은 1 A, 3 A, 5 A, 5 A, 5 A였으며, 아크 전류 30 A일 때, 빔 전류 밀도 3.2 mA/$\textrm{cm}^2$, 평균 증착률 5 $\AA$/sec를 얻었다. 또한 플라즈마 덕트의 바이어스 전압 증가에 따라, 빔 전류 밀도는 증가하였으며, 더 효율적인 빔을 인출할 수 있었다.

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중국산 ICT 품목의 대 한국시장 경쟁력 분석 - 컴퓨터 및 주변기기 품목을 중심으로 - (A Study on the Export Competitiveness of Chinese ICT Items in Korean Market - Focused on the Computer and Peripheral Equipment Items -)

  • 김지용
    • 통상정보연구
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    • 제19권4호
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    • pp.127-145
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    • 2017
  • 본 연구는 미래 성장 엔진으로 부각되고 있는 ICT 산업에 초점을 맞추었고, 특히 한국 ICT 산업의 경쟁자로 급부상하고 있는 중국 ICT 산업의 경쟁력 분석을 통해 한국 ICT 산업의 발전 방안을 찾아 보는 것에 연구의 주목적을 두었다. 상기와 같은 연구 목적 아래 본 연구에서는 다양한 ICT 산업의 품목군 중 ICT 산업의 기반 품목인 컴퓨터 및 주변기기 품목을 조사대상으로 삼았고, 중국산 동 품목들이 한국 시장에서 가지는 경쟁력의 정도를 조사하였다. 분석대상 기간은 2008년 - 2016년이었으며, 분석자료는 한국무역협회에서 제공하는 K-Stat 수출입통계자료를 이용하였고. 분석방법으로 시장점유율지수(MSI), 수출편향지수(EBI) 및 시장별비교우위지수(MCA)를 활용하였다. 분석 결과에 따르면 중국산 컴퓨터 및 주변기기 품목의 대 한국시장 점유율은 지속적으로 증가하고 있으며, 한국 시장에 집중도가 높은 품목이 다수를 차지하였으며, 한국 시장에서 확보한 경쟁력의 정도 또한 상당히 강한 것으로 조사되었다. 위와 같은 분석결과에 대한 대응방안으로 한국산 컴퓨터 및 주변기기 품목 관련 기업들은 동 품목들의 시장가격에 부합하는 제품들의 지속적인 품질개발 노력, 동 품목들간의 융합적 소비자 친화적 제품 개발 및 동 품목들이 한국산이라는 인식이 확실히 소비자들에게 인식될 수 있도록 소비자 인식제고를 위한 마케팅 노력이 필요할 것으로 제시되었다.

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드론 영상을 이용한 Sentinel-2, Landsat-8 위성 NDVI 평가: 벼 병해 발생 지역을 대상으로 (Evaluation of NDVI Retrieved from Sentinel-2 and Landsat-8 Satellites Using Drone Imagery Under Rice Disease)

  • 류재현;안호용;나상일;이병모;이경도
    • 대한원격탐사학회지
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    • 제38권6_1호
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    • pp.1231-1244
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    • 2022
  • 이상기상으로 인해 노지 작물이 스트레스 상황에 노출되는 빈도가 증가하고 있다. 우리나라에서도 대표적인 벼 재배지역에서 대규모의 병해가 발생하는 사례가 나타났으며, 특정 시기에 대규모 필지에서 발생하는 피해를 현장방문으로 조사하는 것은 한계가 있다. 위성 기반의 원격탐사 기법은 시군 영역을 대상으로 작물을 모니터링하기에 유용하나 작물의 생육이상에 따른 민감도 평가가 선행되어야 한다. 본 연구에서는 벼 병해 발생 지역에서 서로 다른 공간해상도를 가지는 위성 기반의 정규화식생지수(normalized difference vegetation index, NDVI)를 드론 영상을 이용하여 평가하였다. 10 m와 30 m의 공간해상도를 가지는 Sentinel-2, Landsat-8 위성 영상을 평가하였으며, 드론 영상은 약 8-10 cm의 공간해상도를 가졌다. 위성 영상에 맞춰 리샘플링(resampling)된 드론 NDVI는 Sentinel-2 NDVI 와 0.867-0.940의 상관관계를 가졌으며, Landsat-8 NDVI와는 0.813-0.934의 상관관계를 가졌다. 센서의 차이, 관측 시점의 차이 등으로 인한 편향(bias) 영향을 최소화하였을 때, Sentinel-2 NDVI는 Landsat-8 NDVI에 비해 드론 NDVI와 0.2-2.8% 더 적은 정규화된 평균 제곱근 오차를 가졌다. 또한, Sentinel-2 NDVI는 드론 NDVI와 병해 피해 정도와 관계없이 일정한 오차를 가졌으나 Landsat-8 NDVI는 병해 피해 정도에 따라 드론 NDVI와 오차 특성이 다르게 나타났다. 농경지 경계에서 오차가 크다는 것을 고려했을 때 공간해상도가 높은 영상을 활용하는 것이 작물 모니터링에 효과적이라고 판단된다.

Fatigue life prediction based on Bayesian approach to incorporate field data into probability model

  • An, Dawn;Choi, Joo-Ho;Kim, Nam H.;Pattabhiraman, Sriram
    • Structural Engineering and Mechanics
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    • 제37권4호
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    • pp.427-442
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    • 2011
  • In fatigue life design of mechanical components, uncertainties arising from materials and manufacturing processes should be taken into account for ensuring reliability. A common practice is to apply a safety factor in conjunction with a physics model for evaluating the lifecycle, which most likely relies on the designer's experience. Due to conservative design, predictions are often in disagreement with field observations, which makes it difficult to schedule maintenance. In this paper, the Bayesian technique, which incorporates the field failure data into prior knowledge, is used to obtain a more dependable prediction of fatigue life. The effects of prior knowledge, noise in data, and bias in measurements on the distribution of fatigue life are discussed in detail. By assuming a distribution type of fatigue life, its parameters are identified first, followed by estimating the distribution of fatigue life, which represents the degree of belief of the fatigue life conditional to the observed data. As more data are provided, the values will be updated to reduce the credible interval. The results can be used in various needs such as a risk analysis, reliability based design optimization, maintenance scheduling, or validation of reliability analysis codes. In order to obtain the posterior distribution, the Markov Chain Monte Carlo technique is employed, which is a modern statistical computational method which effectively draws the samples of the given distribution. Field data of turbine components are exploited to illustrate our approach, which counts as a regular inspection of the number of failed blades in a turbine disk.

한국인 생활욕구의 요인구조 및 관련요인의 영향에 관한 연구 (A Study on the Factor Structure of Koreans' Need of Living and on the Influence of Related Variables)

  • 노영남
    • 대한가정학회지
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    • 제28권1호
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    • pp.67-87
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    • 1990
  • This study was designed with the purpose to analyze the bias and the factor structure of Need of Living and to clear the influence of related variables on Need on Living. The Degree of Importance(Di) and of sufficiency(Ds) of 65 indicators which were the constituent components of Need of Living and were extracted from the 51 preceeding studies was estimated by the 1084 samples including 614 urban and 470 rural residents through the questionaire. The indicators with higher Di and lower Ds than average were considered to show the high level of Need of Living. The main results are as follows; 1. Generally speaking, the level of Di was higher than that of Ds. Specially this was serious in the case of the indicators related with social-economic equity, employment, housing and environment. 2. Di level of the indicators such as physical health, judicial equality, the life of planned expenditure was highest. Specially the equity of income allocation was considered to be more important than the increase of income or asset itself. 3. Ds level of the indicators such as the life of plannel expenditure, the development of transportation and communication and the relationship between parents and children was highest, adn that of the use of leisure time, socialactivity, economic equality and social welfare was lowest. 4. Through the oblique rotation of Factor analysis, 12 factors were extracted (total eigen value 32.663, total variance 50.251%). Specially Factor 1 which was christened as the equality and development of social-economic life was related with 11 indicators and its common variance was 51.68%. 5. The rural residents, the lower income group and the lower educated group, who were told of being under disadvantage and unfair treatment of social-economic status, showed higher suffiency on the equity of income allocation, the freedom of living and expression, and judicial equality. 6. Generally speaking, the urban residents, the group under 39 years old, the higher educated group had more intensive Need of Living than the other groups.

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Effect of Heated Red Bean Pillow Application for College Women with Dysmenorrhea

  • Kim, Jeung-Im
    • 여성건강간호학회지
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    • 제19권2호
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    • pp.67-74
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    • 2013
  • Purpose: Dysmenorrhea is a menstrual condition characterized by severe and frequent cramps and pain. Effective treatment methods for dysmenorrhea are not yet fully understood. This research compares the effects of pain killers and heated red bean pillows. Methods: Data were got on demographic data, menstrual cycle status, and activities of daily living (ADLs) limitations, dysmenorrhea severity and menstrual pain scores. Following a 10% drop-out rate, 44 young women satisfied the inclusion criteria. To prevent any bias, the experimental and control groups were selected from different campuses. We used two sizes of red bean pillows: $13{\times}11.5cm$, weighing 400g; and $15{\times}18cm$, weighing 220g. For analysis, we used IBM SPSS statistics 19.0. Results: Ninety-nine point seven percentage of total subjects reported moderate to severe dysmenorrhea and 63.6% reported as moderate to severe daily activities limitations. The mean pain score with visual analogue scale was $80.2{\pm}9.42$ of 100 and 86.4% used pain killers to alleviate menstrual discomfort in all the subjects. In both groups, all three variables showed significant improvement and the Moos's Menstrual Distress Questionnaire (MDQ) scores changed significantly between menstrual and post-menstrual time point at within groups and not significantly different at premenstrual and menstrual time point at between groups. However, the MDQ score was significantly higher in experimental group than control group at post-menstruation time point and the degree of satisfaction was higher in the control group. Conclusion: This research shows that red-bean pillows on the abdomen are effective in assisting the ADL and diminishing pain severity. With regard to its safety the study indicates it can be a convenient and safe option for female students with menstrual discomfort in schoolas a non-pharmacological self-help.