On the efficiency comparison of certain randomized response strategies

Comparisons between different randomized response strategies have already been performed by several workers but all have concentrated solely on comparing the variances of the appropriate estimators. A very little attention has been paid by these workers to the degree of privacy protection offered to the interviewees. In the present paper, an attempt has been made in this direction and some important randomized response strategies have been compared with the Warner's model, taking into account the aspect of privacy protection. Received February 2000     

二次经营理念在项目经营管理中的应用

通过高速公路项目二次经营管理工作经验,为推行项目二次经营理念,以提高项目经济管理效益,本文对二次经营管理的理念、策划及实施方法进行阐述,为后续类似项目参考。     

企业数据中心初探

建立统一的数据中心应用系统平台,将有效提高数据的共享和利用率,并提供多种应用分析功能,为企业的管理和决策提供更深层次的支持。文章通过分析企业数据中心建设的背景和意义,探讨数据中心在企业发展中的建设过程。     

建筑工程技术专业实训室建设

笔者从事建筑工程教学多年,建筑工程技术专业实训室的建设对于满足学生、学校、企业三方诉求都有着积极意义。     

企业数据中心初探

建立统一的数据中心应用系统平台,将有效提高数据的共享和利用率,并提供多种应用分析功能,为企业的管理和决策提供更深层次的支持。文章通过分析企业数据中心建设的背景和意义,探讨数据中心在企业发展中的建设过程。     

Multivariate t and beta distributions associated with the multivariate F distribution

Relationships between F, skew t and beta distributions in the univariate case are in this paper extended in a natural way to the multivariate case. The result is two new distributions: a multivariate t/skew t distribution (on ℜ^m) and a multivariate beta distribution (on (0,1)^m). A special case of the former distribution is a new multivariate symmetric t distribution. The new distributions have a natural relationship to the standard multivariate F distribution (on (ℜ⁺)^m) and many of their properties run in parallel. We look at: joint distributions, mathematically and graphically; marginal and conditional distributions; moments; correlations; local dependence; and some limiting cases. Received: March 2001     

Simultaneous inspection of several product characteristics

In this paper we consider 100% inspection of a product of which several characteristics have to satisfy given specification limits. A 100% inspection procedure may be necessary to bring the percentage of nonconforming items down to a level acceptable for the consumer. If one can observe the actual values of the characteristics, it would be possible to bring this percentage down to zero. However, quite often this is not possible, as a measurement error occurs in measuring the characteristics. Therefore, it is common practice to inspect each characteristic by comparing its measurement to a test limit which is slightly more strict than the corresponding specification limit. An item then is accepted if for each characteristic the measurement conforms to the corresponding test limit. However, instead of inspecting an individual characteristic merely using its own measurement, it is (much) more efficient to use the measurements of the other characteristics as well, especially if some of the characteristics are highly correlated. In this paper it is shown how the measurements of all the characteristics can be used to test whether an item is conforming.     

Two ge neral classes of search designs for factor screening experiments with factors at three levels

In this paper, we are presenting general classes of factor screening designs for identifying a few important factors from a list of m (≥ 3) factors each at three levels. A design is a subset of 3^m possible runs. The problem of finding designs with small number of runs is considered here. A main effect plan requires at least (2m + 1) runs for estimating the general mean, linear and quadratic effects of m factors. An orthogonal main effect plan requires, in addition, the number of runs as a multiple of 9. For example, when m=5, a main effect plan requires at least 11 runs and an orthogonal main effect plan requires 18 runs. Two general factor screening designs presented here are nonorthogonal designs with (2m− 1) runs. These designs, called search designs permit us to search for and identify at most two important factors out of m factors under the search linear model introduced in Srivastava (1975). For example, when m=5, the two new plans given in this paper have 9 runs, which is a significant improvement over an orthogonal main effect plan with 18 runs in terms of the number of runs and an improvement over a main effect plan with at least 11 runs. We compare these designs, for 4≤m≤ 10, using arithmetic and geometric means of the determinants, traces, and maximum characteristic roots of certain matrices. Two designs D1 and D2 are identical for m=3 and this design is an optimal design in the class of all search designs under the six criteria discussed above. Designs D1 and D2 are also identical for m=4 under some row and column permutations. Consequently, D1 and D2 are equally good for searching and identifying one important factor out of m factors when m=4. The design D1 is marginally better than the design D2 for searching and identifying one important factor out of m factors when m=5, … , 10. The design D1 is marginally better than the D2 for searching and identifying two important factors out of m factors when m=5, 7, 9. The design D2 is somewhat better than the design D1 for m=6, 8. For m=10, D1 is marginally better than D2 w.r.t. the geometric mean and D2 is marginally better than D1 w.r.t. the arithmetic mean of the maximum characteristic roots.     

The use of studentized diagnostics in regression

Recent work by LaMotte (1999) uncovered redundancies and inconsistencies in the current practice of selected deletion diagnostics in regression. The present study extends earlier work to include further diagnostics on using different methods. Benchmarks adjusted to the scale of each diagnostic are given to assure consistency across diagnostics. Case studies illustrate anomalies in the use of these diagnostics as currently practiced. Alternative diagnostics are given to gauge effects of single-case deletions on variances and biases in prediction and estimation. Received: November 1999     

浅析国家基本药物制度与合理用药的关系

国家基本药物制度与合理用药的方向和目标是一致的,且对合理用药的实践有促进作用。目前我国基本药物制度在推进合理用药的过程中,在遴选、推行、监管、评价、宣传等方面存在一些不足,基本药物制度的实施体系需要进一步完善,以更好地促进我国合理用药水平的提高。     

On estimating the median from survey data using multiple auxiliary information

A new method to derive confidence intervals for medians in a finite population is presented. This method uses multi-auxiliary information through a multivariate regression type estimator of the population distribution function. A simulation study based on four real populations shows its behaviour versus other known methods.     

Multivariate stable ARMA processes with time dependent coefficients

This paper considers the class of m-variate autoregressive moving average (ARMA) processes with stable innovations and time dependent coefficients. A set of suitable AR and MA regularity conditions is given to ensure existence and uniqueness of valid solutions. A simple form of the above solution is expressed in terms of one sided Green's matrix functions associated with the AR operator. We solve the prediction problem arising in this class of models. A few examples are added to support the general theory.     

Feasible implementation of taxation methods

This paper studies implementation of taxation methods in one-commodity environments in which the incomes of the agents are unknown to the planner. Feasibility out of equilibrium imposes that the mechanism depend on the environment. We present two mechanisms. The first one, which requires complete information, implements every taxation method in Nash, strong and coalition-proof equilibrium. The second, where informational requirements are relaxed, implements a large class of consistent and monotone methods in subgame perfect equilibrium. Neither mechanism employs the off-equilibrium devices used by the general theory. Under fully private information no method is implementable. Received: 12 March 1997 / Accepted: 21 July 1998     

Implementation of stable solutions in a restricted matching market

I analyze the admission mechanism used in Spanish universities. The system is open to strategic manipulation. This is because students are not allowed to express the whole list of available options. However, the mechanism implements the set of stable matchings in Nash equilibrium and the student's optimum in strong equilibrium. The mechanism also implements the students' optimum, in Nash equilibrium, under the class of “non-reverse” preferences. All these properties come from the fact that colleges do not have the opportunity to misrepresent their preferences. Received: 30 June 1995 / Accepted: 31 January 1997     

Impossibility of Nash implementation in two-person economies

In this note, we prove two impossibility results of Nash implementation in two-person economies. First, we will show the non-existence of continuous and balanced mechanisms which implement the Walrasian correspondence. Second, by adding a convexity assumption of mechanisms, we present the impossibility of continuous implementation of Pareto optimal and individually rational allocations in balanced way. Received: 16 April 1996 / Accepted: 25 April 1997     

An extensive form solution to the adverse selection problem in principal/multi-agent environments

When agents have quasi-linear preferences, every incentive compatible social choice function can be implemented by a simple extensive form mechanism, even if agents are allowed to use mixed strategies. The second stage of the mechanism, which is used to elicit the agents' true preferences, is not reached in equilibrium; it gives agents strict dominant strategies, so equilibrium outcomes are not sensitive to agents' beliefs off the equilibrium path. This solves the multiple equilibrium problem of a principal facing several agents: the mechanism implements any solution to the principal's second best maximization problem. The specification of incentive compatibility constraints in the principal's problem presupposes a precise knowledge of the agents' beliefs. However, the above mechanism can be modified to implement the principal's second best (to within arbitrarily small perturbations of transfers), regardless of the agents' conditional beliefs. Received: 30 April 1997 / Accepted: 16 September 1997     

Three dual regression schemes for the Lukacs theorem

In the paper we study regressional versions of Lukacs' characterization of the gamma law. We consider constancy of regression instead of Lukacs' independence condition in three new schemes. Up to now the constancy of regressions of U=X/(X + Y) given V=X + Y for independent X and Y has been considered in the literature. Here we are concerned with constancy of regressions for X and Y while independence of U and V is assumed instead.