• Communications for Statistical Applications and Methods
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• 제13권1호
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• pp.61-72
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• 2006

When using the well-known variance estimator of Sen (1953) and Yates and Grundy (1953) in inclusion probability proportional to size sampling, we often encounter the problems due to the calculation of the joint probabilities. Sarndal (1996) and Knottnerus (2003) proposed alternative strategies for variance estimation to avoid those problems in the traditional method. We discuss some of practical issues that arise when they are used. Also, we describe the traditional strategy using a sampling procedure available in a statistical software. It would be one of the attractive choices for design-based variance estimation.

• The Journal of Asian Finance, Economics and Business
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• 제7권11호
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• pp.563-573
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• 2020

This research examined the effect of KHD Leadership toward Sustainable Shareholder Value and mediated by IT & Business Strategy Alignement and Integrated Supply Chain Management. Therefore, with this research, it is expected to be able to develop the KHD Leadership in State-owned enterprises' (SOEs) Indonesian. The population in this study were all echelon 1, 2, and 3 employees in the PT Pupuk Kalimantan Timur, PT Pupuk Petrokimia Gresik, PT Pupuk Sriwidjaja Palembang, PT Pupuk Kujang Cikampek, PT Pupuk Iskandar Muda, as many as N = 1002 people. The appropriate sampling technique used is Proportional Stratified Random Sampling (n=300 employees). The statistical analysis used is SEM-WarpPLS method. IT & Business Strategy Alignement and Integrated Supply Chain Management significant and positive on Sustainable Shareholder Value. IT & Business Strategy Alignment and IT Integrated Suppy Chain Management is a mediating variable between the influence of KHD Leadership on Sustainable Shareholder Value. Novelty in this research is the development of Ki Hadjar Dewantara Leadership as the development of the concept of Javanese leadership that grows inherent in Indonesian society, especially Javanese society and is believed to be applicable in business and industrial organizations in Indonesia, of course it can also be implemented in Pupuk Indonesia Holding Company.

• 한국환경보건학회지
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• 제36권3호
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• pp.171-181
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• 2010

Semivolatile aerosols exist as vapor and particles at the same time in room temperature and each phase has different intake and uptake mechanisms. This characteristic requires substantial consideration during exposure assessment of semivolatile aerosol. Some sampling methods for solid particles pose high possibility of evaporative loss during sampling. Therefore, when establishing sampling strategy for them, the factors affecting the phase distribution of semivolatile aerosol should be counted including semivolatile aerosol of interest and sampling methods used. Evaluation for phase distributions of semivolatile aerosols is also recommended. Metalworking fluids, pesticides, asphalt fumes, diesel exhaust, and environmental tobacco smoke are common health-related semivolatile aerosols in workplaces.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.295-298
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• 2000

In this research, a novel sampling strategy for a CMM to inspect freeform surfaces is proposed. Unlike primitive surfaces, it is not easy to determine the number of sampling points and their locations for inspecting freeform surfaces. Since a CMM operates with slower speed in measurement than optical measuring devices, it is important to optimize the number and the locations of sampling points in the inspection process. When a complete inspection of a surface is required, it becomes more critical. Among various factors to cause shape errors of a final product, curvature characteristic is essential due to its effect such as stair-step errors in rapid prototyping and interpolation errors in NC tool paths generation. Shape errors are defined in terms of the average and standard deviation of differences between an original model and a produced part. Proposed algorithms determine the locations of sampling points by analyzing curvature distribution of a given surface. Based on the curvature distribution, a surface area is divided into several sub-areas. In each sub-area, sampling points are located as further as possible. The optimal number of sub-areas. In each sub-area, sampling points are located as further as possible. The optimal number os sub-areas is determined by estimating the average of curvatures. Finally, the proposed method is applied to several surfaces that have shape errors for verification.

• Journal of Information Processing Systems
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• 제14권4호
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• pp.948-960
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• 2018

Many mobile sensing frameworks have been developed to help researcher doing their mobile sensing research. However, energy consumption is still an issue in the mobile sensing research, and the existing frameworks do not provide enough solution for solving the issue. We have surveyed several mobile sensing frameworks and carefully chose one framework to improve. We have designed an adaptive sampling module for a mobile sensing framework to help solve the energy consumption issue. However, in this study, we limit our design to an adaptive sampling module for the location and motion sensors. In our adaptive sampling module, we utilize the significant motion sensor to help the adaptive sampling. We experimented with two sampling strategies that utilized the significant motion sensor to achieve low-power consumption during the continuous sampling. The first strategy is to utilize the sensor naively only while the second one is to add the duty cycle to the naive approach. We show that both strategies achieve low energy consumption, but the one that is combined with the duty cycle achieves better result.

• Journal of the Korean Statistical Society
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• 제31권2호
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• pp.143-152
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• 2002

In an effort to make a right choice among ratio estimation strategies and PPS sampling strategies, we conduct an empirical investigation of the relative performances of three ratio estimation strategies and four PPS estimation strategies using a set of 12 natural populations. The quality of a strategy is measured in the traditional way, namely with the consideration of efficiency, achieved coverage rate of the nominal 99% confidence interval and approach to normality (asymmetry).

• 한국임상수의학회지
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• 제29권1호
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• pp.63-67
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• 2012

Mosquitoes are the vectors of a number of viral diseases in cattle, such as Akabane disease, bovine ephemeral fever, Ainovirus infection, Chuzan virus infection, and Ibaraki disease. These diseases are transmitted from an infected animal to a non-infected host via the blood feeding of the vector. In Korea, the National Veterinary Research and Quarantine Services, Ministry for Food, Agriculture, Forestry and Fisheries is responsible for planning, implementation, laboratory investigations and reporting the results of the national surveillance program for mosquito-borne bovine diseases (MBD). The surveillance program, which was started in 1993, focused to determine the seroprevalence of each disease in cattle herds in space and time. From the epidemiological point of view, more important component of the surveillance program is to monitor infection rates in vectors for specific pathogens because this information is essential for a more precise understanding the dynamics of these diseases in a given environment and for determining risk of transmission. The aim of this study was to describe and compare methods for estimation of vector infection rates using maximum likelihood (MLE) and minimum infection rate in pooled samples. Factors affecting MLE such as number of pools, pooling size and diagnostic test performance are also discussed, assuming some hypothetical sampling scenarios for MBD.

• Communications for Statistical Applications and Methods
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• 제24권3호
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• pp.255-269
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• 2017

This article explores the analysis of longitudinal surveys in which same units are investigated on several occasions. Multivariate exponential ratio type estimator has been proposed for the estimation of the finite population median at the current occasion in two occasion longitudinal surveys. Information on several additional auxiliary variables, which are stable over time and readily available on both the occasions, has been utilized. Properties of the proposed multivariate estimator, including the optimum replacement strategy, are presented. The proposed multivariate estimator is compared with the sample median estimator when there is no matching from a previous occasion and with the exponential ratio type estimator in successive sampling when information is available on only one additional auxiliary variable. The merits of the proposed estimator are justified by empirical interpretations and validated by a simulation study with the help of some natural populations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.32-34
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• 2008

Latin Hypercube sampling strategy(LHS)는 출력변수에 의한 목적함수들의 기댓값의 추정을 위한 입력변수를 생성하는데 사용할 수 있는 샘플링 포인트 추출 방법으로, 샘플링 포인트의 "quality"를 향상시켜준다. multi-objective Pare optimization 에 근거한 LHS와 ($1+\lambda$) 진화기법으로 이루어진 최적화 algorithm을 제안 하였고, 이를 이용하여 6MW BLDC 전동기의 코깅토크를 최소화 하였다, 총 2단계의 최적 설계를 통해 초기형상의 코킹토크에 비해 19%로 감소하였다.

• 한국의류학회지
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• 제24권7호
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• pp.953-963
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• 2000

This study intended to analyse the factors of brand image and brand image positioning of domestic 20’s female apparel(formal wear) among the consumer groups segmented by benefits sought in apparel and to provide marketing strategy of brand image. The subject of this study were 605 working women in their 20’s living in seoul, and the model sampling was done by convenienced sampling method based on the subjects age and occupation. Survey based on references and former studies was used. and statistical methods such as frequency, percentage, mean, factor analysis, preference regression were applied. The results of this study were as follows. 1. The factor structures of brand image were classified into symbolism/aesthetics, and practicality. 2. Perception, ideal preference vector, and brand preference of brand image were proven to be significantly different among the four segmented consumer groups.