• 제목/요약/키워드: Distribution science

검색결과 19,678건 처리시간 0.039초

Hidden truncation circular normal distribution

  • Kim, Sung-Su;Sengupta, Ashis
    • Journal of the Korean Data and Information Science Society
    • /
    • 제23권4호
    • /
    • pp.797-805
    • /
    • 2012
  • Many circular distributions are known to be not only asymmetric but also bimodal. Hidden truncation method of generating asymmetric distribution is applied to a bivariate circular distribution to generate an asymmetric circular distribution. While many other existing asymmetric circular distributions can only model an asymmetric data, this new circular model has great flexibility in terms of asymmetry and bi-modality. Some properties of the new model, such as the trigonometric moment generating function, and asymptotic inference about the truncation parameter are presented. Simulation and real data examples are provided at the end to demonstrate the utility of the novel distribution.

소나무 수심 정각재의 건조 중 3차원 함수율 분포와 변이 (Three-dimensional Distribution and Variation of Moisture Content of Boxed-heart Square Timber of Pinus densiflora During Drying)

  • 강욱;이형우;정우양
    • Journal of the Korean Wood Science and Technology
    • /
    • 제34권1호
    • /
    • pp.7-14
    • /
    • 2006
  • 국산 소나무 간벌재를 이용한 수심 정각새(단면치수 $150{\times}150mm$)의 안전하고 신속한 건조를 위하여 열풍건조와 마이크로파건조중 수심 정각새의 함수율 분포와 그 변이를 3차원적으로 탐색하였다. 실험결과 마이크로파건조를 통하여 72시간 이내에 함수율 10% 미만까지 건조가 가능하였고 표면할열 발생도 최소화할 수 있었다. 건조 중 함수율 분포는 마이크로파건조의 경우 초기함수율 분포에 영향을 크게 받았다. 그러나 열기건조의 경우 초기함수율 분포가 건조초기에만 영향을 미치는 것으로 나타났다.

Distributional Pattern of Tree Species in Response to Soil Variables in a Semi Natural Tropical Forest of Bangladesh

  • Ara, Saida Hossain;Limon, Mahedi Hasan;Kibria, Mohammad Golam
    • Journal of Forest and Environmental Science
    • /
    • 제37권1호
    • /
    • pp.14-24
    • /
    • 2021
  • A plant community is a group of populations that coexist in space and interact directly or indirectly with the environment. In this paper, we determined the pattern of tree species composition in response to soil variables in Khadimnagar National Park (KNP), which is one of the least studied tropical forests in Bangladesh. Soil and vegetation data were collected from 71 sample plots. Canonical Correspondence Analysis (CCA) with associated Monte Carlo permutation tests (499 permutations) was carried out to determine the most significant soil variable and to explore the relationship between tree species distribution and soil variables. Soil pH and clay content (pH with p<0.01 and Clay content with p<0.05) were the most significant variables that influence the overall tree species distribution in KNP. Soil pH is related to the distribution and abundance of Syzygium grande and Magnolia champaca, which were mostly found and dominant species in KNP. Some species were correlated with clay content such as Artocarpus chaplasha and Cassia siamea. These observations suggest that both the physico-chemical properties of soil play a major role in shaping the tree distribution in KNP. Hence, these soil properties should take into account for any tree conservation strategy in this forest.

A Comparative Study on the Distribution Regulation Policy in Korea and Foreign Countries

  • Park, Chul-Ju;Kim, Dae-Yun
    • 유통과학연구
    • /
    • 제11권9호
    • /
    • pp.43-49
    • /
    • 2013
  • Purpose - The competitiveness of small- and medium-sized distribution companies has weakened with the entry of large distribution companies and Super Super Markets (SSMs). These companies have nationwide distribution networks and capital to take over street markets, thereby threatening the very survival of small merchants. In order to help these small- and medium-sized merchants, the government has recently reinforced distribution regulations for large distribution companies. Research design, data, methodology - The purpose of this study is to review domestic and foreign distribution regulations and to provide direction for establishing domestic distribution policies in the future. Results - The government must fully reassess its assistance policy for small and medium distribution companies to enable them to engage in differentiated competition with large retailers, based on their own strengths. This will allow all interested parties to coexist. Conclusions - Government assistance policies for small and medium distributors such as traditional markets must be reorganized. The objective is to ultimately protect small and medium distributors and allow them to coexist on their own strengths, rather than have regulations for large retail stores.

A Cascaded D-STATCOM Integrated with a Distribution Transformer for Medium-voltage Reactive Power Compensation

  • Lei, Ertao;Yin, Xianggen;Chen, Yu;Lai, Jinmu
    • Journal of Power Electronics
    • /
    • 제17권2호
    • /
    • pp.522-532
    • /
    • 2017
  • This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.

Service Distribution Strategy on Business Performance of Padang Restaurants in North Jakarta

  • CHRISTIAN, Michael;HARIS, Kevin;INDRIYARTI, Eko Retno;WIBOWO, Suryo;SUNARNO, Sunarno
    • 유통과학연구
    • /
    • 제19권12호
    • /
    • pp.57-69
    • /
    • 2021
  • Purpose: This study aims to measure whether the business performance of Padang restaurants in North Jakarta is primarily affected by service distribution strategy and other factors, specifically the local-based organizational culture and entrepreneurial orientation. Research design, data and methodology: This quantitative research has used Structural Model-Partial Least Square (PLS-SEM) with SMART PLS 3.0 as the analytical tool. The study's sample focus is the owner or person in charge of the Padang restaurant business in North Jakarta. Data has been collected using a questionnaire instrument with a Likert scale scale ('1-strongly disagree' to '5-strongly agree'). A total of 86 samples with a random technique were obtained from three areas in North Jakarta: Kelapa Gading, Pademangan, and Penjaringan. Results: Interestingly, this research finds that service distribution strategy does not affect business performance, either directly or indirectly. Business performance in this study is affected by entrepreneurial orientation. In additional results, the local organizational culture significantly affects the entrepreneurial orientation, but does not affect the business performance in terms of management process. Conclusions: This study provides practical implications for restaurant businesses regarding the use of local cultural concepts to consider strategies for survival in today's challenging times while continuing operations during limitations.

Research on flow characteristics in supercritical water natural circulation: Influence of heating power distribution

  • Ma, Dongliang;Zhou, Tao;Feng, Xiang;Huang, Yanping
    • Nuclear Engineering and Technology
    • /
    • 제50권7호
    • /
    • pp.1079-1087
    • /
    • 2018
  • There are many parameters that affect the natural circulation flow, such as height difference, heating power size, pipe diameter, system pressure and inlet temperature and so on. In general analysis the heating power is often regarded as a uniform distribution. The ANSYS-CFX numerical analysis software was used to analyze the flow heat transfer of supercritical water under different heating power distribution conditions. The distribution types of uniform, power increasing, power decreasing and sine function are investigated. Through the analysis, it can be concluded that different power distribution has a great influence on the flow of natural circulation if the total power of heating is constant. It was found that the peak flow of supercritical water natural circulation is maximal when the distribution of heating power is monotonically decreasing, minimal when it is monotonically increasing, and moderate at uniform or the sine type of heating. The simulation results further reveal the supercritical water under different heat transfer conditions on its flow characteristics. It can provide certain theory reference and system design for passive residual heat removal system about supercritical water.

Developing Parameters of Forecasting Models in the Field of Distribution Science to Forecast Vietnamese Seafarer Resources

  • DANG, Dinh-Chien;NGUYEN, Thai-Duong;NGUYEN, Nhu-Ty
    • 유통과학연구
    • /
    • 제19권8호
    • /
    • pp.47-56
    • /
    • 2021
  • Purpose: Maritime sector is fundamental to international trade; there is no doubt that seafarers have played an essential role in maritime shipping and distribution science industry. Thus, this study uses Grey models to predict the number of seafarers in Vietnam expecting to provide a range of future seafarers. Research design, data and methodology: Statistics data are adopted for numbers of seafarers by Vietnam Maritime Administration categorizing into three types: Officers at Management level, Officers at Operational level and Navigation - Engine officer cadet. Results: The results have showed that a lack of qualified seafarers in the distribution industry, which has become a global issue and Vietnam is facing challenges of providing enough supply of seafarers in the next few years. Since there has been a concern of the unbalance between demand and supply of seafarers, researches in maritime sector needs a high accuracy in forecasting the number of available qualified seafarers in Vietnam. Conclusion: This method can be applied to predict numbers of other human resources in transportation, distribution and/or logistics industries when the information is poor and insufficient. The next few years are predicted to witness a downtrend in sailors - oilers which leads to the fact that the total number of available seafarers is decreased.

A Design of a Metadata for Edutech Tools Distribution

  • Yong KIM;Dinh Tuan LONG;Ock Tae KIM
    • 유통과학연구
    • /
    • 제22권5호
    • /
    • pp.81-91
    • /
    • 2024
  • Purpose: Edutech, which is the application of information and communication technology to education, is being introduced in various ways across all levels, from primary and secondary education to lifelong education. The purpose of this study was to present metadata about Edutech tools to provide the method for providing various Edutech tools. Research design, data, and methodology: To achieve the research purpose, the necessary elements for the metadata of Edutech tools were first derived based on a literature review. A focus group interview (FGI) with experts was conducted to gather opinions on the developed metadata, further validating its appropriateness. Results: The metadata area consisted of "Basic Information", "Product Information", and "Utilization Information". The "Basic Information" section had 9 items, "Product Information" had 8 items, and "Utilization Information" was presented with 4 items. Conclusions: This study proposed metadata for Edutech tools, which can be utilized to develop distribution system to proliferate and harness various Edutech tools in the educational setting. For the future establishment of an Edutech tool distribution system based on this metadata, it's imperative to operate a credible platform to ensure a stable distribution framework.

탈모 환자의 적외선 체열 진단상 안면부 체열 특성 (Infrared Thermographic Imaging in Patients with Alopecia)

  • 이태후;문정배;안경애;이혜정
    • 대한한의학회지
    • /
    • 제27권2호
    • /
    • pp.244-252
    • /
    • 2006
  • Objectives : To examine any potential relationships between the types of alopecia and the facial heat distribution in patients with alopecia. Methods : 183 patients with alopecia participated in this study to provide facial heat distribution measured by the Infrared Thermography Scanner (ITS, Nec San-ei Instruments Ltd, Japan). The thermography scan was used in a light- and heat-protected room after 20 minutes' of rest. 1.5m of distance was maintained between the patients and the scanner. Results : Specificity in the type of facial heat distribution was found as follow. 1. Types of facial heat distribution can be classified as T-type and diffused patterns. 2. There was a significant difference in the pattern of facial heat distribution among different types of alopecia (p=0.002): facial heat distribution appeared T-type in androgenic alopecia, alopecia areata, and telogen effluvium (71.3%, 85.7%, 70.4%), whereas diffused pattern was dominant in seborrheic alopecia (55.6%). 3. There was a significant difference in the pattern of facial heat distribution between men and women (p<0.001) : While the T-type and diffused type appeared equally in men (50.6% : 49.4%), T-type was dominant in women (88.0% vs. 12.0%). Conclusions : We conclude that the pattern of facial heat distribution differs depending on the types of alopecia and gender. These differences may provide useful information for diagnosis and clinical therapy for this population.

  • PDF