• 제목/요약/키워드: Deviation Index

검색결과 571건 처리시간 0.022초

NOAA/AVHRR NDVI를 이용한 북한지역 봄 가뭄 분석 (Analysis of Spring Drought Using NOAA/AVHRR NDVI for North Korea)

  • 장민원;유승환;최진용
    • 한국농공학회논문집
    • /
    • 제49권6호
    • /
    • pp.21-33
    • /
    • 2007
  • Different vegetation indices from satellite images have been used for monitoring drought damages, and this study aimed to develop a drought index using NOAA/AVHRR NDVI(Normalized Difference Vegetation Index) and to analyze the temporal and spatial distribution of spring drought severity in North Korea from 1998 to 2001. A new drought index, DevNDVI(Deviation of NDVI), was defined as the difference between a monthly NDVI and average monthly NDVI at the same cover area, and the DevNDVI images at all years except for 2001 demonstrated the drought-damaged areas referred from various domestic and foreign publications. The vegetation of 2001 showed high vitality despite the least amount of rainfall among the target years, and the reason was investigated that higher temperature above normal average would shift the growing stages of plants ahead. Therefore, complementary methods like plant growth models or ground survey data should be adopted in order to evaluate drought-induced plant stress using satellite-based NDVI and to make up far the distortion induced by other environments than lack of precipitation.

지역사회 보건사회지표를 이용한 지역사회 건강수준 관련 요인 분석 (Analysis of Community Health Status and Related Factors Using Community Health and Social Indicators)

  • 박은옥
    • 지역사회간호학회지
    • /
    • 제19권1호
    • /
    • pp.13-26
    • /
    • 2008
  • Purpose: The purpose of this paper was to investigate community health status and related factors using community health and social indicators. Method: Data sources were reviewed and data for 10 categories, 75 indicators were collected. Community health status and health-related factors were categorized, and the means and standard deviation of individual indicators were obtained and standardized scores were calculated. In addition, through factor analysis of individual indicators by category using the scores and using the resultant factor coefficients as weights, indexes were calculated by area. Correlation and regression were analyzed. Result: Each indicator was highly correlated with each index, and the indexes were highly correlated with one another. Correlation coefficients were above 0.8 between community health index and population, education, housing, and economy, between population and education, housing and economy, between education and housing and economy, and between housing and economy, environment and industry. But multicollinearity was not found in the result. Significant factors on community health index were population, health personnel and facilities, education, housing and economy, and R-square were 92.4%. Conclusion: Health determinants such as population, health personnel and facilities, education, housing and economy could be influencing factors on community health in community level. These results showed the importance of intersectoral collaboration within a local government. Overall community health can be enhanced by intersectoral collaboration.

  • PDF

증기터빈 1단 Shell 압력측정에 의한 교축유동 고찰 (A Study of Steam Turbine Throttle Flow from Measured First Stage Shell Pressure)

  • 윤인수;이재헌;유호선;문승재;이태구;허진혁
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 2008년도 춘계학술대회논문집
    • /
    • pp.373-376
    • /
    • 2008
  • Industrial Steam Turbine first stage shell pressure is related to throttle flow. Theoretically, first stage shell pressure could, therefore, be measured and used as an index of turbine throttle flow. However, accurate flow measurements show that this pressure is not a reliable index of the actual flow. Data analysis of steam turbinessubjected to ASME acceptance tests shows that the use of first stage shell pressure as an index of throttle flow produced errors as large as 9.6 %. The mean of the errors was +2.2% with a standard deviation of ${\pm}$2.8 %. Applications that require an accuratedetermination of turbine steam flow, such as turbine acceptance testing, should, therefore, not rely on this method. Therefore, First stage shell pressure measurement serves as a valid and economical indicator of turbine throttle flow in cases where a high degree of accuracy in throttle flow measurement is not required but repeatability is desired, such as for boiler control. Generally speaking, Steam turbine first stage shell pressure may also be a very useful monitor of turbine performance when used with certain other turbine measurements.

  • PDF

개념 설계 평가를 위한 제품 품질지수 (Product Quality Index for Concept Design Evaluation)

  • 정진하;박영원
    • 한국생산제조학회지
    • /
    • 제19권4호
    • /
    • pp.521-528
    • /
    • 2010
  • A product system will be improved continually until requirements are satisfied. It is true that considering alternative designs to improve product system is hard work; it is also true that selecting an adequate design idea that represents the needs of stakeholders concerned and meets effectiveness factors properly is not an easy work, either. In the process of driv-ing an idea and designing, which is called Design Phase, there are lots of existing tools for testing the driven idea in DFSS. But, those kinds of tools do not offer the function that helps to select the technically better design idea among alternative design ideas that have the same evaluation level. Moreover it is inappropriate to select adequate alternative design ideas by just verifying only the evaluation table in pugh matrix, since satisfied deviation val-ues are low when there is a too competitive mass product system in a market. Also, for the IT product with short life cycle, faster and more effective testing tool is needed. Therefore, the 'roduct quality index' is suggested in order to select an appropriate candidate design concept for system development that meets requirements by using 'deality concept' pro-vided by TRIZ. According to the result of this research, it is possible to select technically better idea fast and effectively; it is confirmed by applying the approach to the case of LCD BLU (Back Light Unit).

A Point Clouds Fast Thinning Algorithm Based on Sample Point Spatial Neighborhood

  • Wei, Jiaxing;Xu, Maolin;Xiu, Hongling
    • Journal of Information Processing Systems
    • /
    • 제16권3호
    • /
    • pp.688-698
    • /
    • 2020
  • Point clouds have ability to express the spatial entities, however, the point clouds redundancy always involves some uncertainties in computer recognition and model construction. Therefore, point clouds thinning is an indispensable step in point clouds model reconstruction and other applications. To overcome the shortcomings of complex classification index and long time consuming in existing point clouds thinning algorithms, this paper proposes a point clouds fast thinning algorithm. Specifically, the two-dimensional index is established in plane linear array (x, y) for the scanned point clouds, and the thresholds of adjacent point distance difference and height difference are employed to further delete or retain the selected sample point. Sequentially, the index of sample point is traversed forwardly and backwardly until the process of point clouds thinning is completed. The results suggest that the proposed new algorithm can be applied to different targets when the thresholds are built in advance. Besides, the new method also performs superiority in time consuming, modelling accuracy and feature retention by comparing with octree thinning algorithm.

$CO_2$ 용접의 단락이행 조건에서 스패터 발생과 파형인자와의 관계 (Relation between Spatter Generation and Waveform factor of $CO_2$ Welding in Short-Circuit Condition)

  • 김희진;강봉용;이강희;유중돈
    • Journal of Welding and Joining
    • /
    • 제16권3호
    • /
    • pp.95-101
    • /
    • 1998
  • Waveforms of $CO_2$ gas shielded arc welding in short circuit transfer mode was studied with the waveform analysis program, which can calculate various waveform factors such as number of short circuit event, mean and standard deviation of short circuit time and arc time. The calculated values of these factors were correlated independently or in combination with the spatter generation rate to figure out the most reliable index for evaluating spatter generation and further for arc stability. As a result this study, it was confirmed that the spatter generation tends to decrease with the increase of short circuit frequency. Further to this, it was also found that as the short circuit frequency increases the short circuit event becomes more uniform resulting in the decrease of standard deviations ($\sigma$values) of short circuit time and arc time. This result demonstrated that these factors are strongly correlated with each other and thus any one of these factors can be used for the evaluation index. In the discussion, however, short circuit frequency was proposed for the most practical index in evaluating the arc stability of short circuit transfer mode since it is the one which could be monitored in-process condition without any complex caculation process.

  • PDF

Risk and Return of Islamic and Conventional Indices on the Indonesia Stock Exchange

  • SURYADI, Suryadi;ENDRI, Endri;YASID, Mukhamad
    • The Journal of Asian Finance, Economics and Business
    • /
    • 제8권3호
    • /
    • pp.23-30
    • /
    • 2021
  • The purpose of this study is to compare the level of risk and return of Islamic stocks in the Jakarta Islamic Index (JII) with conventional stocks on the IDX30 in the period from January 2017 to July 2019. The Sharpe ratio method is used to calculate risk and stock returns. The performance of the stock portfolio is measured by comparing the risk premium portfolio with the portfolio risk that is expressed as a standard deviation of the total risk. This study uses secondary data collected by the Indonesia Stock Exchange (IDX), which provides the names of stock issuers included in the JII and IDX30 indices along with their montly closing price. The results of the descriptive analysis show that the JII Sharpe ratio index from January 2017 to July 2019 is from the minimum range of -0.28820 to a maximum range of 0.05622, while the IDX30 Sharpe ratio index from January 2017 to July 2019 is from the minimum range of -0.09290 to the maximum range of 0.17436. The results of inferential analysis using a different test show that there is a significant difference between the Sharpe ratio JII and IDX30 in measuring the performance of the stock portfolio.

인공신경망을 이용한 사출성형품의 무게 안정성 제어에 대한 연구 (A Study on the Stability Control of Injection-molded Product Weight using Artificial Neural Network)

  • 이준한;김종선
    • 한국산업융합학회 논문집
    • /
    • 제23권5호
    • /
    • pp.773-787
    • /
    • 2020
  • In the injection molding process, the controlling stability of products quality is a very important factor in terms of productivity. Even when the optimum process conditions for the desired product quality are applied, uncontrollable external factors such as ambient temperature and humidity cause inevitable changes in the state of the melt resin, mold temperature. etc. Therefore, it is very difficult to maintain prodcut quality. In this study, a system that learns the correlation between process variables and product weight through artificial neural networks and predicts process conditions for the target weight was established. Then, when a disturbance occurs in the injection molding process and fluctuations in the weight of the product occur, the stability control of the product quality was performed by ANN predicting a new process condition for the change of weight. In order to artificially generate disturbance in the injection molding process, controllable factors were selected and changed among factors not learned in the ANN model. Initially, injection molding was performed with a polypropylene having a melt flow index of 10 g/10min, and then the resin was replaced with a polypropylene having a melt floiw index of 33 g/10min to apply disturbance. As a result, when the disturbance occurred, the deviation of the weight was -0.57 g, resulting in an error of -1.37%. Using the control method proposed in the study, through a total of 11 control processes, 41.57 g with an error of 0.00% in the range of 0.5% deviation of the target weight was measured, and the weight was stably maintained with 0.15±0.07% error afterwards.

자세변화가 자율신경계에 미치는 영향 (The Influence of Position Change on Autonomic Nervous System Function)

  • 김인배;김은경;강종호
    • 대한물리의학회지
    • /
    • 제9권1호
    • /
    • pp.63-68
    • /
    • 2014
  • PURPOSE: The purpose of this study was to examine the position changes with tilt table on autonomic nervous system using heart rate variability analysis. METHODS: Fourty healthy adult males volunteered in this study. The low frequency, high frequency and low frequency/high frequency ratio and mean heart rate, standard deviation of all normal R-R intervals, root mean square of successive differences, heart rate variability index were measured at the tilt table angle of $0^{\circ}$, $45^{\circ}$ and $90^{\circ}$ with pulsoximeter. Data were analyzed one-way ANOVA and LSD post hoc test. RESULTS: The mean heart rate, low frequency and low frequency/high frequency ratio increased significantly at higher angle of tilt table(p<.05). The root mean square of successive differences, heart rate variability index decreased significantly at lower angle of tilt table(p<.05). The standard deviation of all normal R-R intervals, high frequency decreased at higher angle of tilt table did not show significant difference. CONCLUSION: The symphathetic activity increased significantly at higher angle of tilt table. The parasymphathetic activity decreased at higher angle of tilt table, but the difference were not significant. The autonomic adaptation, balance and heart rate variability decreased significantly at higher angle of tilt table. Based on these results, in the treatment of patients with a change in posture precedence should be carefully treated. Further studies are necessary to determine the most safety and effective methods.

유물실측을 통한 여자저고리의 치수연구 (A Study on stylistic measurement of Chogori with Museum specimens)

  • 유송옥
    • 복식
    • /
    • 제32권
    • /
    • pp.21-30
    • /
    • 1997
  • Chogori the basic upper garment of korea costume occupies an important role in tra-ditional dressing and continues to be in use to the present days. Of course there has been changes in the length and line of Chogori with the flow of time based on the Ancient Yoo. This is a study of the 14 parts of Chgori based on statistical analysis by computing the practical measuements. Here the statistical analysis is a objective and quantitative of the stylistic changes in Chogori with time. In this study from the data the Mean and Standard deviation has been evaluated and periodic change is shown by graph to test the periodic change T-test Regressional analysis Index analysis has been used. The results are as follows: 1. The length of clothing has changed with time except the sleeve length. Here the length of clothing means all the other measurements ex-cept the sleeve Thus while the measurements of sleeve length has been uniquely unchanged the other measurements have influenced each other. 2. Generally the form of Chogori had the tendency towards smallness in the 19th cen-tury. But it tended to get larger in the 20th century. 3. Compared to other periods the mode of 19th and 20th century Chogori was widely ac-cepted as the Standard deviation of that period was very narrow. 4. The results seen from the regressional analysis of the Cho-sun period woman's Chogori satisfy the t-value and R-squared and thus support the regression formula presump-tion. 5. From the index analysis it is revealed that with decrease in the armhole measurement sleeve measurement and neckband; relatively same decrease in the wrist measurement; and very marked decrease in the sideline measurement.

  • PDF