• Title/Summary/Keyword: 벤치

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BMDL of blood lead for ADHD based on two longitudinal data sets (주의력 결핍 과잉 행동장애를 종점으로 하는 혈중 납의 벤치마크 용량 하한 도출: 두 동집단 자료의 병합)

  • Kim, Si Yeon;Ha, Mina;Kwon, Hojang;Kim, Byung Soo
    • The Korean Journal of Applied Statistics
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    • v.31 no.1
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    • pp.13-28
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    • 2018
  • The ministry of Environment of Korea initiated two follow-up surveys in 2005 and 2006 to investigate environmental effect on children's health. These two cohorts, referred to as the 2005 Cohort and 2006 Cohort, were followed up three times every two years. This data set was referred to as the Children's Health and Environmental Research (CHEER) data set. This paper reproduces the existing research results of Kim et al. (Journal of the Korean Data and Information Science Society, 25, 987-998, 2014) and Lee et al. (The Korean Journal of Applied Statistics, 29, 1295-1310, 2016) and derive a benchmark dose lower limit (BMDL) for blood lead level for attention deficit hyperactivity disorder (ADHD) after pooling two cohort data sets. The different ADHD rating scales were unified by applying the conversion formula proposed by Lee et al. (2016). The random effect model and AR(1) model were built to reflect the longitudinal characteristics and regression to the mean phenomenon. Based on these models the BMDLs for blood lead levels were derived using the BMDL formula and the simulation. We obtained a hight level of BMDLs when we pooled two independent cohort data sets.

An Empirical Study on the Measurement of Clustering and Trend Analysis among the Asian Container Ports Using the Variable Group Benchmarking and Categorical Variable Models (가변 그룹 벤치마킹 모형과 범주형 변수모형을 이용한 아시아 컨테이너항만의 클러스터링측정 및 추세분석에 관한 실증적 연구)

  • Park, Rokyung
    • Journal of Korea Port Economic Association
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    • v.29 no.1
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    • pp.143-175
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    • 2013
  • The purpose of this paper is to show the clustering trend by using the variable group benchmarking(VGB) and categorical variable(CV) models for 38 Asian ports during 9 years(2001-2009) with 4 inputs(birth length, depth, total area, and number of crane) and 1 output(container TEU). The main empirical results of this paper are as follows. First, clustering results by using VGB show that Shanghai, Qingdao, and Ningbo ports took the core role for clustering. Second, CV analysis focusing on the container throughputs indicated that Singapore, Keelong, Dubai, and Kaosiung ports except Chinese ports are appeared as the center ports of clustering. Third, Aqaba, Dubai, Hongkong, Shanghai, Guangzhou, and Ningbo ports are recommended as the efficient ports for the target of clustering. Fourth, when the ports are classified by the regional location, Dubai, Khor Fakkan, Shanghai, Hongkong, Keelong, Ningbo, and Singapore ports are the core ports for clustering. On the whole, other ports located in Asia should be clustered to Dubai, Khor Fakkan, Shanghai, Hongkong, Ningbo, and Singapore ports. The policy implication of this paper is that Korean port policy planner should introduce the VGB model, and CV model for clustering among the international ports for enhancing the efficiency of inputs and outputs.

A Study on the Stepwise Benchmarking Method for Efficient Operation of Student Education Support (학생 교육지원의 효율적 운영에 대한 단계적 벤치마킹 방안 연구)

  • Jeong, Kyu-Han;Lee, Jang-Hee
    • Journal of Practical Engineering Education
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    • v.12 no.1
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    • pp.213-230
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    • 2020
  • Until now, various educational budgets, facilities, and programs have been put into school education, but the results have not been clearly evaluated. This study presents a model to analyze the effectiveness of educational support for students in high schools across the country. In this model, we first use EM cluster analysis to make clusters with similar inputs for school operation, and then calculate the relative efficiency in each cluster by using Network DEA analysis. The Network DEA analysis has a two-stage structure where the first stage uses six inputs in terms of school infrastructure to generate outputs such as the number of academic persistence. In the Network DEA analysis, the second stage uses 10 inputs in terms of school programs to generate outputs such as the number of enrollees to higher learning and the number of employees and per capita usage of library as the connection variable. Based on the efficiency analysis results, Tier analysis is performed by applying the Euclidean distance to select targets for benchmarking. In this study, we applied the model to analyze the efficiency of educational support by collecting data regarding student education support in general and vocational high school nationwide. The stepwise benchmarking method proposed that the target be selected for efficiency improvement step by step, taking into account inefficient school elements to complement the problem of the choice of benchmarking targets. Based on this study, it is expected that schools with low efficiency of educational support for students will be used as basic data for stepwise benchmarking for efficient operation of educational support for students.

A Study on Workbench-based Dynamic Service De-sign and Construction of Computational Science Engineering Platform (계산과학공학 플랫폼의 워크벤치 기반 동적 서비스 설계 및 구축에 관한 연구)

  • Kwon, Yejin;Jeon, Inho;Ma, Jin;Lee, Sik;Cho, Kum Won;Seo, Jerry
    • Journal of Internet Computing and Services
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    • v.19 no.3
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    • pp.57-66
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    • 2018
  • EDISON ( EDucation-research Integration through Simulation On the Net) is a web simulation service based on cloud compu-ting. EDISON provides that web service and provide analysis result to users through pre-built infrastructure and various calcu-lation nodes computational science engineering problems that are difficult or impossible to analysis as user's personal resources to users. As a result, a simulation execution environment is provided in a web portal environment so that EDISON can be ac-cessed regardless of a user's device or operating system to perform computational science engineering analysis simulation. The purpose of this research is to design and construct a workbench based real - time dynamic service to provide an integrat-ed user interface to the EDSION system, which is a computational science engineering simulation and analysis platform, which is currently provided to users. We also devised a workbench-based user simulation service environment configuration. That has a user interface that is similar to the computational science engineering simulation software environment used locally. It can configure a dynamic web environment such as various analyzers, preprocessors, and simulation software. In order to provide these web services, the service required by the user is configured in portlet units, and as a result, the simulation service using the workbench is constructed.

Hybrid Control of a Benchmark Cable-Stayed Bridge Considering Nonlinearity of a Lead Rubber Bearing (납고무받침의 비선형성을 고려한 벤치마크 사장교의 복합제어)

  • Park, Kyu-Sik;Jung, Hyun-Jo;Lee, In-Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.4
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    • pp.51-63
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    • 2002
  • This paper presents a hybrid control strategy for seismic protection of a benchmark cable-stayed bridge, which is provided as a testbed structure for the development of strategies for the control of cable-stayed bridges. This benchmark problem considers the cable-stayed bridge that is scheduled for completion in Cape Girardeau, Missouri, USA in 2003. Seismic considerations were strongly considered in the design of this bridge due to the location of the bridge in the New Madrid seismic zone and its critical role as a principal crossing of the Mississippi river. Based on detailed drawings of this cable-stayed bridge, a three-dimensional linearlized evaluation model has been developed to represent the complex behavior of the bridge. A set of eighteen evaluation criteria has been developed to evaluate the capabilities of each control strategy. In this study, a hybrid control system is composed of a passive control system to reduce the earthquake-induced forces in the structure and an active control system to further reduce the bridge responses, especially deck displacements. Conventional base isolation devices such as lead rubber bearings are used for the passive control design and Bouc-Wen model is used to simulate the nonlinear behavior of these devices For the active control design, ideal hydraulic actuators are used and on $H_2$/LQG control algorithm is adopted. Numerical simulation results show that the performance of the proposed hybrid control strategy is quite effective compared to that of the passive control strategy and slightly better than that of the active control strategy. The hybrid control method is also more reliable than the fully active control method due to the passive control part. Therefore, the proposed hybrid control strategy can effectively be used to seismically excited cable-stayed bridges.

Analyzing the Effects of the Initiation Sequences of the MDS Blasting Method on Rock Fracturing Using SPH-FEM Coupling Technique (SPH-FEM 연계기법을 이용한 MDS 발파법의 기폭패턴별 암석파괴 효과 분석)

  • Byung-Hee Choi;Young-Geun Kim;Ki-Chan Jeon;Se-Wook Oh
    • Explosives and Blasting
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    • v.41 no.3
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    • pp.13-25
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    • 2023
  • The conventional bench blasting method uses the bottom initiation in all blast holes in a round, whereas the MDS (mixture detonation system) method applies the bottom and top initiations alternately according to the spatial position or temporal sequence of each blast hole. The former and latter are respectively called the SMDS (spatial MDS) and TMDS (temporal MDS) methods. Another variant called MMDS (modified MDS) is designed for the specific use in the site having a fly-rock problem. This study compares the MDS method to the conventional method in the aspect of rock fracturing effect. The comparison is made by numerical simulations for a two-row bench blasting model in the LS-DYNA. The SPH-FEM coupling method is utilized for constructing the blasting model. The SPH elements are used for the rock in the near-field region of the blast holes, and the FEM elements for that in the far-field region. The RHT material model is used for the rock. As a result of the simulations, it was found that up to 0.4 m deeper damaged zone was appeared in the SMDS method than in the conventional method for the case of the burden 1.6 m and bench height 3.0 m. In addition, the fly-rock velocity to the normal direction of the bench slope was appeared about 2.0 m/s lower in the MMDS method compared to the other methods.