• Journal of the Korean Statistical Society
• /
• 제30권4호
• /
• pp.637-644
• /
• 2001

We investigated two kinds of mean square error (MSE) estimator of homogeneous linear estimator (HLE) for the population total under stratified multi-stage sampling. One is studied when the second stage variance component is estimable and the other is found in cafe it is not estimable. The proposed estimators are necessary forms of non-negative unbiased MSE estimators of HLE.

• 대한치과교정학회지
• /
• 제25권6호
• /
• pp.697-704
• /
• 1995

Chicken calvarial bone is known to contain various cell types, but their exact composition is unknown. By characterizing the chicken calvarial bone biochemically, it can be used to study biochemical, histochemical actions of bone cells in general. Calvaria of 18-day-old white leg horn embryo was aseptically dissected and bone cell populations were isolated by sequential enzymatic digestion. Histochemical study for osteoclast-like bone cell. population was performed with tartrate resistant acid phosphatase(TRAP) stain and for osteoblast-like bone cell population, alkaline phosphatase(ALP) stain was performed. Biochemical study for osteoblast-like bone cell population was performed using alkaline phosphatase(ALP) assay. Following conclusions were obtained from this study. 1. TRAP positive multi and mononuclear cells were mostly observed in group I and II, indicating that osteoclast-like bone cell population is mostly found in these groups. 2. All the cultured groups showed almost equal ALP activities and were positive for ALP stain, indicating that osteoblast-like bone cell population is evenly dispersed in all culture groups. 3. Experimental group treated with $1,25(OH)_{2}D_3$ showed increase in ALP activity in contrast to the control group, confirming previous studies that $1,25(OH)_{2}D_3$ increases ALP activities in in vitro bone cultures. 4. Results from von Kossa's stain indicated that in vitro bone formation had occured after 3 weeks of culture with beta-glycero phosphate.

• Management Science and Financial Engineering
• /
• 제13권2호
• /
• pp.29-46
• /
• 2007

This paper makes an attempt to compare the two important methods for finding solutions of multi-item inventory problem with more than one conflicting objectives. Panda et al.[9] discusses a distance-based method to find the best possible compromise solution with variation of priority under the given weight structure. In this paper, the problem in [9] is revisited through the Pareto-optimal front of genetic algorithm with the help of a situation of retail stocking of FMCG business. The advantages of using the solutions from the perspective of the decision maker obtained through multi-objective optimization are highlighted in terms of population search, weighted goals and priority structure, cost, set of compromise solutions along with prevention of stock-out situation.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
• /
• pp.1071-1076
• /
• 2003

Evolutionary algorithm is recognized as a promising approach to solving multi-objective combinatorial optimization problems. When no preference information of decision makers is given, multi-objective optimization problems have been commonly used to search for diverse and good Pareto optimal solution. In this paper we propose a new multi-objective evolutionary algorithm based on competitive coevolutionary algorithm, and demonstrate the applicability of the algorithm. The proposed algorithm is designed to promote both population diversity and rapidity of convergence. To achieve this, the strategies of fitness evaluation and the operation of the Pareto set are developed. The algorithm is applied to job shop scheduling problems (JSPs). The JSPs have two objectives: minimizing makespan and minimizing earliness or tardiness. The proposed algorithm is compared with existing evolutionary algorithms in terms of solution quality and diversity. The experimental results reveal the effectiveness of our approach.

• 한국경영과학회지
• /
• 제28권2호
• /
• pp.1-15
• /
• 2003

This paper presents a new evolutionary algorithm to solve complex multi-level integration problems, which is called multi-level symbiotic evolutionary algorithm (MEA). The MEA uses an efficient feedback mechanism to flow evolution information between and within levels, to enhance parallel search capability, and to improve convergence speed and population diversity. To show the MEA's applicability, It is applied to the integrated planning of production and distribution in supply chain management. The encoding and decoding methods are devised for the integrated problem. A set of experiments has been carried out, and the results are reported. The superiority of the algorithm's performance is demonstrated through experiments.

• Structural Engineering and Mechanics
• /
• 제45권2호
• /
• pp.211-232
• /
• 2013

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.

• Architectural research
• /
• 제12권1호
• /
• pp.1-8
• /
• 2010

This research paper explores selected behavioral outcomes of a multi-sensory environment. An experimental study was conducted at a specialized facility for the ageing in Sweden. The objective was to explore the effects of agitated behaviors of ageing residents with dementia and to identify any short-term effects. Appointed nursing staff was instructed to record physically and verbally agitated behaviors on three occasions; pre-session, mid-session, and post-session. Over seven months, nine participants received sixty-one sessions in the multi-sensory room. ANOVA and Post hoc multiple comparisons were performed to identify the differences in mean between each session. Generally irritated/frustrated behavior and eating/drinking non foods revealed statistically significant differences, while there were no significant results in verbally agitated behavior. One short-term effect was observed in one agitated category; a reduction of generally irritated/frustrated behavior. These results suggest that the multi-sensory environment can have positive effects on some manifestations of agitated behavior. This study proposes that a multi-sensory environment may be recommended as an alternative intervention for physically agitated behavior among this category of residents. However, more research is needed to understand the specific effects and the best use of the multi-sensory environment for this population.

• 환경영향평가
• /
• 제22권6호
• /
• pp.713-724
• /
• 2013

In terms of waste load allocation, inequality of waste load discharge must be considered as well as economic aspects such as minimization of waste load abatement. The inequality of waste load discharge between areas was calculated with Gini coefficient and was included as one of the objective functions of the multi-objective waste load allocation. In the past, multi-objective functions were usually weighted and then transformed into a single objective optimization problem. Recently, however, due to the difficulties of applying weighting factors, multi-objective genetic algorithms (GA) that require only one execution for optimization is being developed. This study analyzes multi-objective waste load allocation using NSGA-II-aJG that applies Pareto-dominance theory and it's adaptation of jumping gene. A sensitivity analysis was conducted for the parameters that have significant influence on the solution of multi-objective GA such as population size, crossover probability, mutation probability, length of chromosome, jumping gene probability. Among the five aforementioned parameters, mutation probability turned out to be the most sensitive parameter towards the objective function of minimization of waste load abatement. Spacing and maximum spread are indexes that show the distribution and range of optimum solution, and these two values were the optimum or near optimal values for the selected parameter values to minimize waste load abatement.

• 한국수자원학회논문집
• /
• 제40권9호
• /
• pp.677-685
• /
• 2007

본 연구의 목적은 개념적인 강우-유출모형인 Tank 모형의 매개변수를 산정하기 위한 다목적 유전자알고리즘의 적용성을 평가하는 것이다. 다목적 유전자알고리즘 기법으로는 최근에 가장 많이 사용되는 기법중의 하나인 NSGA-II를 채택하여 Tank 모형과 결합하였으며, 4가지 목적함수(유출용적오차, 평균제곱근 오차, 고수유량 평균제곱근 오차 및 저수유량 평균제곱근 오차)값을 최소화하는 형태의 목적함수를 적용하였다. NSGA-II는 목적함수의 개수가 많아지면 한 번의 실행에 의해 굉장히 많은 수의 파레토최적해를 구하는 단점을 가지고 있기 때문에 구해진 파레토최적해 중에서 어떤 해가 최우선해 인지를 결정해야 할 필요가 있으며, 이러한 고차원적인 의사결정을 위하여 선호적순서화(preference ordering) 기법을 적용하였다. NSGA-II를 이용하여 Tank모형의 매개변수를 추정할 때 초기조건이 최적화과정에 미칠 수 있는 영향을 최소화하기 위해 세대수(generation number)와 개체군의 크기(population size)에 대한 민감도분석을 수행하였다. 분석결과 Tank모형의 매개변수 최적화를 위한 세대수와 개체군 크기의 초기 값을 각각 900번과 1000개로 선정하는 것이 적합한 것으로 나타났다.

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