• Title/Summary/Keyword: 95% distribution

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Implementation of the Calculation Method for 95% Upper Limit of Effluent Water Quality of Sewage Treatment Plant for Total Maximum Daily Loads : Percentile Ranking Method (수질오염총량관리를 위한 환경기초시설 배출수질의 통계적 평가방법 개선 : 선형보간법의 백분위수방법)

  • Park, Jae Hong;Kim, Dong Woo;Oh, Seung-Young;Rhew, Doug Hee;Jung, Dong Il
    • Journal of Korean Society on Water Environment
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    • v.24 no.6
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    • pp.676-681
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    • 2008
  • The evaluation of the effluent water quality of sewage treatment plant is one of the most important factor in calculating total maximum daily loads (TMDLs). Current method to calculate 95% upper limit of effluent water quality of sewage treatment plant assuming normal distribution of data needs to be implemented in case of non-normal distribution. We have investigated the applicability of percentile ranking method as a non-parametric statistical analysis in case of non-normal distribution of data.

Derivation of Optimal Design Flood by Gamma and Generalized Gamma Distribution Models(II) -On the Generalized Gamma Distribution Model- (Gamma 및 Generalized Gamma 분포 모형에 의한 적정 설계홍수량의 유도(II) -Generalized Gamma 분포모형을 중심으로-)

  • 이순혁;박명근;맹승진;정연수;류경선
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.40 no.2
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    • pp.59-68
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    • 1998
  • This study was conducted to derive optimal design floods by generalized gamma distribution model of the annual maximum series at eight watersheds along Geum, Yeongsan and Seomjin river systems. Design floods obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model were compared by the relative mean errors and graphical fit along with 95% confidence limits plotted on gamma probability paper. The results were analyzed and summarized as follows. 1. Basic statistics and parameters were calculated by the generalized gamma distribution model using different methods for parameters. 2. Design floods according to the return periods were obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model. 3. It was found that design floods derived by sundry averages method for parameters and Cunnane method for plotting position in the generalized gamma distribution are much closer to those of the observed data in comparison with those obtained by the other methods for parameters and for plotting positions from the viewpoint of relative mean errors. 4. Reliability of design floods derived by sundry averages method in the generalized gamma distribution was acknowledged within 95% confidence interval.

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The Impact of COVID-19 on Earnings Management in the Distribution and Service Industries

  • RYU, Haeyoung;CHAE, Soo-Joon
    • Journal of Distribution Science
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    • v.20 no.4
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    • pp.95-100
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    • 2022
  • Purpose: This study aimed to investigate whether distribution and service companies maintained their accounting information quality and provided reliable information despite the economic changes occurring after the outbreak of the COVID-19 pandemic in Korea. The distribution industry has enjoyed increased demand as many companies expanded their untact distribution channels, including to online sales. However, as the pandemic drags on, their future prospects remain uncertain. Research design, data, and methodology: In this study, we define 2018-2019 as the "pre COVID-19 period" and 2020 as the "post COVID-19 period." An empirical analysis was performed using a regression model that includes POST, the independent variable, indicating the post COVID-19 period, and discretionary accruals(DA), a proxy for earnings management, as a dependent variable. Results: The analysis shows that the coefficient of POST is significantly positive (+) for the dependent variable DA. This finding suggests that distribution and service companies engaged in more earnings management during the post COVID-19 period than during the pre COVID-19 period, indicating their awareness of the uncertainty of future business performance as the pandemic persists. An additional analysis confirmed that smaller companies with fewer stakeholders and higher information asymmetry tend to engage more in earnings management than larger companies.

Evaluation on the Accuracy of Targeting Error Correction Through the Application of Target Locating System in Robotic CyberKnife (로봇 사이버나이프에서 위치인식시스템을 이용한 Targeting Error값 보정의 정확성 평가)

  • Jeong, Young-Joon;Jung, Jae-Hong;Lim, Kwang-Chae;Cho, Eun-Ju
    • The Journal of Korean Society for Radiation Therapy
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    • v.21 no.1
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    • pp.1-7
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    • 2009
  • Purpose: The purpose is to evaluate the accuracy of correcting the targeting error through the Target Location System (TLS) for the location change error of the reference point which arises from the movement or motion of patient during the treatment using the CyberKnife. Materials and Methods: In this test, Gafchromic MD-55 film was inserted into the head and neck phantom to analyze the accuracy of the targeting, and then the 6 MV X-ray of CyberKnife (CyberKnife Robotic Radiosurgery System G4, Accuray, US) was irradiated. End to End (E2E) program was used to analyze the accuracy of targeting, which is provided by Accuray Corporation. To compute the error of the targeting, the test was carried out with the films that were irradiated 12 times by maintaining the distance within the rage of $0{\pm}0.2\;mm$ toward x, y, z from the reference point and maintaining the angle within the rage of $0{\pm}0.2^{\circ}$ toward roll, pitch, yaw, and then with the films which were irradiated 6 times by applying intentional movement. And the correlation in the average value of the reference film and the test film were analyzed through independent samples t-test. In addition, the consistency of dose distribution through gamma-index method (dose difference: 3%) was quantified, compared, and analyzed by varying the distance to agreement (DTA) to 1 mm, 1.5 mm, 2 mm, respectively. Results: E2E test result indicated that the average error of the reference film was 0.405 mm and the standard deviation was 0.069 mm. The average error of the test film was 0.413 mm with the standard deviation of 0.121 mm. The result of independent sampling t-test for both averages showed that the significant probability was P=0.836 (confidence level: 95%). Besides, by comparing the consistency of dose distribution of DTA through 1 mm, 1.5 mm, 2 mm, it was found that the average dose distribution of axial film was 95.04%, 97.56%, 98.13%, respectively in 3,314 locations of the reference film, consistent with the average dose distribution of sagittal film that was 95.47%, 97.68%, 98.47%, respectively. By comparing with the test film, it was found that the average dose distribution of axial film was 96.38%, 97.57%, 98.04%, respectively, at 3,323 locations, consistent with the average dose distribution of sagittal film which was 95.50%, 97.87%, 98.36%, respectively. Conclusion: Robotic CyberKnife traces and complements in real time the error in the location change of the reference point caused by the motion or movement of patient during the treatment and provides the accuracy with the consistency of over 95% dose distribution and the targeting error below 1 mm.

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Pedestrian Distribution in High-Rise Commercial Complexes: An Analysis of Integrating Spatial and Functional Factors

  • Xu, Leiqing;Xia, Zhengwei
    • International Journal of High-Rise Buildings
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    • v.5 no.2
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    • pp.95-103
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    • 2016
  • One of the key problems in the design of high-rise commercial complex is how to guide reasonable pedestrian distribution in commercial space. In this study, pedestrian distribution in three high-rise commercial complexes in Shanghai and Hong Kong was studied using spatial configuration analysis software Space Syntax and quantification of physical elements in commercial spaces, such as functional attractiveness, entrances, escalators, level variations and passage width. Additionally, in an attempt to integrate functions with spatial integration and spatial depth, two combination variables, the spatial coefficient of function (IF) and spatial depth coefficient of function (F/D), were proposed. The results of the correlation analysis and multiple regression analyses reflected the following: (1) Regarding the influence on pedestrian distribution, there was a synergistic and complementary relationship between function and space; (2) The comprehensive flow distribution analytic model could successfully interpret flow distribution in high-rise commercial complexes and its R Square ranged up to about 70% in the three cases; (3) The spatial coefficient of function (IF) and spatial depth coefficient (F/D) could effectively integrate functions and spatial configuration, which could help close the gap between over-emphasis on function in commercial research and the lack of consideration of function in space-syntax analysis.

Development of Bus Load Forecasting System based on Windows95 : Part I (윈도우즈95에 기초한 모선수요예측시스템의 개발(I))

  • Jeon, Dong-Hoon;Song, Seok-Ha;Lim, Joo-Il;Hwang, Kab-Ju
    • Proceedings of the KIEE Conference
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    • 1996.11a
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    • pp.169-171
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    • 1996
  • In this paper, we have developed bus load forecasting system (BUSLOF) based on Windows 95. It has been developed for the secure operation of electric power system. It forecasts regional load and bus load using regional distribution factor(RDF) and bus distribution factor (BDF) which are calculated from bus load in the past. It is equipped with graphic user interface(GUI) which enables a user to easily access to the system. The performance of the developed system is estimated in sample data.

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The Production-Distribution Problem with Multiple Objectives (다수목표(多數目標)를 고려(考慮)한 생산(生産)-수송문제(輸送問題)에 관한 연구(硏究))

  • Gang, In-Seon;Yun, Deok-Gyun
    • Journal of Korean Society for Quality Management
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    • v.19 no.1
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    • pp.95-102
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    • 1991
  • This paper is concerned with the production-distribution problem with multiple conflicting objectives. In reality business firms should take account not only of the profit maximization but of various environmental criteria, namely customer services, in order to improve the business logistics. A production-distribution model of goal porgramming type considering the lead time and distribution cost by products is constructed, the solution algorithm is developed, which is based on the Ignizio's method. A numerical example is given to demonstrate the applicability of goal programming for production-distribution problem.

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A study on the uncertainty of setpoint for reactor trip system of NPPs considering rectangular distributions

  • Youngho Jin;Jae-Yong Lee;Oon-Pyo Zhu
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1845-1853
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    • 2024
  • The setpoint of the reactor trip system shall be set to consider the measurement uncertainty of the instrument channel and provide a reasonable and sufficient margin between the analytical limit and the trip setpoint. A comparative analysis was conducted to find out an appropriate uncertainty combination method through an example problem. The four methods were evaluated; 1) ISA-67.04.01 method, 2) the GUM95 method, 3) the modified GUM method developed by Fotowicz, and 4) the modified IEC61888 method proposed by authors for the pressure instrument channel presented in ISA-RP67.04.02 example. The appropriateness of each method was validated by comparing it with the result of Monte Carlo simulation. As a result of the evaluation, all methods are appropriate when all measurement uncertainty elements are normally distributed as expected. But ISA-67.04 method and GUM95 method overestimated the channel uncertainty if there is a dominant input element with rectangular distribution among the uncertainty input elements. Modified GUM95 methods developed by Fotowicz and modified IEC61888 method by authors are able to produce almost the same level of channel uncertainty as the Monte Carlo method, even when there is a dominant rectangular distribution among the uncertainty components, without computer-assisted simulations.