• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1504-1514
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• 2018

The objective of this study is to compare the suitability of a non-parametric and 3 parametric distributions in the characterization of prediction intervals of photovoltaic power forecasts with high confidence levels. The prediction intervals of the forecasts are calculated using a method based on recent past data similar to the target forecast input data, and on a distribution assumption for the forecast error. To compare the suitability of the distributions, prediction intervals were calculated using the proposed method and each of the 4 distributions. The calculations were done for one year of day-ahead forecasts of hourly power generation of 432 PV systems. The systems have different sizes and specifications, and are installed in different locations in Japan. The results show that, in general, the non-parametric distribution assumption for the forecast error yielded the best prediction intervals. For example, with a confidence level of 85% the use of the non-parametric distribution assumption yielded a median annual forecast error coverage of 86.9%. This result was close to the one obtained with the Laplacian distribution assumption (87.8% of coverage for the same confidence level). Contrasting with that, using a Gaussian and Hyperbolic distributions yielded median annual forecast error coverage of 89.5% and 90.5%.

• Journal of Astronomy and Space Sciences
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• v.6 no.2
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• pp.75-89
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• 1989

The Spacelab 1 data represented the first multiband spectral measuremets of the ${N_2}^{+}$ first negative ion bands system in the thermospheric dayglow, and the first opportunity to make a detailed comparison of the vibrational and rotational distributions over bands out to v'=5. The main purpose of this study was to decuced the excitation processes of ${N_2}^{+}$(1N) bands by determining vibrational population distributions for the upper states of ${N_2}^{+}$(1N). The vibrational population distributions to achieve a best fit to the measured Spacelab 1 data were summarized and also compared with those theoretically derived.

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.435-438
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• 2000

Diameter distributions describe forest stand structure information. Prediction equations for percentiles of diameter distribution and parameter recovery procedures for the Weibull distribution function based on four percentile equations were applied to develop prediction system of even-aged slash pine stand structure development in terms of the number of stems per diameter class changes. Four percentiles of the cumulative diameter distribution were predicted as a function of stand characteristics. The predicted diameter distributions were tested against the observed diameter distributions using the Kolmogorov-Smirnov two sample test at the ${\alpha}$=0.05 level. Statistically, no significant differences were detected based on the data from 236 evaluation data sets. This stand level diameter distribution prediction system will be useful in slash pine stand structure modeling and in updating forest inventories for the long-term forest management planning.

• Earthquakes and Structures
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• v.11 no.1
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• pp.109-127
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• 2016

This paper examines the contribution of three sources of uncertainties to probabilistic seismic behaviour of wood frame buildings, including ground motions, intensity and seismic mass. This sensitivity analysis is performed using three methods, including the traditional method based on the conditional distributions of ground motions at given intensity measures, a method using the summation of conditional distributions at given ground motion records, and the Monte Carlo simulation. FEMA P-695 ground motions and its scaling methods are used in the analysis. Two archetype buildings are used in the sensitivity analysis, including a two-storey building and a four-storey building. The results of these analyses indicate that using data-fitting techniques to obtain probability distributions may cause some errors. Linear interpolation combined with data-fitting technique may be employed to improve the accuracy of the calculated exceeding probability. The procedures can be used to quantify the risk of wood frame buildings in seismic events and to calibrate seismic design provisions towards design code improvement.

• Water for future
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• v.19 no.3
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• pp.239-248
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• 1986

Monthly wind stress, wind stress curl and volume transport stream functions are computed in the Eastern Sea(Japan Sea) based upon observed wind and atmospheric pressure data respectively. The presented two results show different distributios on locality and season but as common features the results reveal the northwesterly surface wind stress \ulcorner 새 the monsoon in winter, south to southwesterly wind stress \ulcorner 새 the southerly wind in summer and strond anticyclonic curl in the northern part on the Eastern Sea(Japan Sea) in winter. In the distributions obtained from the sea level atmospheric pressure data, the maximum value of the wind stress and of curls of small scales are shown off the southeast coast of Siberia and northeast coast of Korea. Volume transport distributions obtained from the Sverdrup relationship suggest that the strong northward boundary current can be formed along the northeast coast of Korea in winter and weak southward boundary current in summer.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1059-1071
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• 2008

In a balanced factorial design with a nested factor where crossed factors as well as a nested factor exist simultaneously, powers of the rank transformed FR statistic for testing the main, nested and interaction effects are superior to those of the parametric F statistic. In heavy tailed distributions such as exponential and double exponential distributions, powers of the FR statistic show much higher level than those of the F statistic. Further powers of the F and FR statistic for testing the main effect show the highest level in an absolute size as compared with powers of the F and FR statistic for testing the nested and interaction effects. However powers of the FR statistic for testing the nested and interaction effects rather than the main effect are greater in a relative size than powers of F statistic for the all population distributions.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.62.1-62.1
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• 2014

Metallicity distribution of globular clusters (GCs) provides an important clue for star formation history of their host galaxy. With an assumption that GCs are generally old, GC colors have been used as a proxy of GC metallicities. Bimodal GC color distributions observed in most large galaxies have, for decades, been interpreted as bimodal metallicity distributions, indicating the presence of two populations within a galaxy. However, the conventional view has been challenged by a new theory that non-linear GC color-metallicity relations (CMRs) can cause a bimodal color distribution even from a single-peaked metallicity distribution. Using the photometric and spectroscopic data of NGC 5128 GCs in combination with stellar population simulation models, we examine the effect of non-linearity in GC CMRs on the transformation of GC color distributions into metallicity distributions. Although, in some colors, offsets are present between observations and models in the CMRs, their overall shape agrees well for various colors. After the offsets are corrected, the observed spectroscopic metallicity distribution is well reproduced via modeled CMRs from various color distributions having different morphologies. On the other hand, the linearly converted metallicity distributions from GC colors show a significant discrepancy with the observed spectroscopic metallicity distribution. We discuss the implications of our results.

• Journal of Distribution Science
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• v.21 no.12
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• pp.15-22
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• 2023

Purpose: Business education is in high demand whereas knowledge is critical for an individual's professional development in general, and for teachers in particular. In this research, the effect of the distributions of teachers' business knowledge on schools' achievement were investigated. Research design, data and methodology: This study employs a quantitative method to investigate the level of business knowledge distributions of teachers on schools' achievement. 155 business studies subject teachers were categorised into 66 respective schools to measure the correlation and regression between teachers' business knowledge distribution and schools' achievement. Results: The results of the study show that there is a significant relationship between school achievement from the aspect of teachers' business knowledge distributions, with the score of, r = 0.345, p < 0.05. The value of R² shows a moderate relationship between the teachers' knowledge distributions on school achievement but still plays a role in determining the measurement of the school's level of achievement. Conclusions: It is concluded that the relationship between teacher's business knowledge and school achievement in the subject of Business Studies is significant. This study proves that the teacher's knowledge about business is very important in guaranteeing the success of students who took this subject.

• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.971-971
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• 2009

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.5
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• pp.400-405
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• 2013

The purpose of this study is to develop a composite platform for knowledge extractions, visualizations, and inference. Generally, the big data sets were frequently used in the healthcare and medical area. To help the knowledge managers/users working in the field, this study is focused on knowledge management (KM) based on Data Mining (DM), Knowledge Distribution Map (KDM), Decision Tree (DT), RDBMS, and SQL-inference. The proposed mechanism is composed of five key processes. Firstly, in Knowledge Parsing, it extracts logical rules from a big data set by using DM technology. Then it transforms the rules into RDB tables. Secondly, through Knowledge Maintenance, it refines and manages the knowledge to be ready for the computing of knowledge distributions. Thirdly, in Knowledge Distribution process, we can see the knowledge distributions by using the DT mechanism.Fourthly, in Knowledge Hierarchy, the platform shows the hierarchy of the knowledge. Finally, in Inference, it deduce the conclusions by using the given facts and data.This approach presents the advantages of diversity in knowledge representations and inference to improve the quality of computer-based medical diagnosis.