Eine Invarianzeigenschaft für Startverteilungen einer Klasse stochastischer Prozesse

Summary This paper discusses some concepts of mixing for stochastic processes with discrete time. The idea of mixing, which is defined with respect to a starting distribution , means that the tranjectories of the process get out of any set with -measure zero with probability one. Such -mixing processes satisfy an invariance property; an asymptotic event has probability zero under any starting distribution, provided that it has probability zero under the starting distribution . Concerring stationary Markov chains these results imply a weak zero-one-law the relation of which with well-known stronger versions especially for aperiodic Harris chains and with the notions of weak ergodicity and a.s. triviality is studied.     

A numerical representation of semiorders on a countable set

Let be a semiorder on a countable setX and letx⁰ y if and only if either there existsx withxxy or there existsx withxxy. Then ⁰ is a preference relation with transitive indifference, which can be represented by a utility functionf of the usual sort. It is well known that is represented by a pair of real-valued functionsu, v, in the sense thatxy if and only ifu(x)>v(y). We prove that there exists a pair of functionsu, v, representing , such thatu+v is the utility function which represents in the usual sense. Moreover it is easily seen that, for such a pair of functionsu, v, we havex⁰ y if and only if eitheru(x)>u(y) or (u(x)=u(y) andv(x)>v(y)).

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Sommario Consideriamo unsemiordine su un insiemeX numerabile e poniamox⁰ y se e solo se esistex tale chexxy, oppure esistex tale chexxy. In questo caso ⁰ è unordine debole, che può essere rappresentato da una funzione di utilitàf nel senso usuale. D'altra parte è rappresentato da una coppia di funzioniu, v, nel senso chexy se e solo seu(x)>v(y). In questo lavoro si prova che ammette una rappresentazioneu, v tale chex⁰ y se e solo seu(x)+v(x)>u(y)+v(y). Si dimostra altresì che, con riguardo ad una siffatta rappresentazioneu, v di , riescex⁰ y se e solo seu(x)>u(y) oppure (u(x)=u(y) ed anchev(x)>v(y)).

     

Bootstrapping Confidence Intervals for Linear Programming Efficiency Scores: With an Illustration Using Italian Banking Data

This article suggests a method for introducing a stochastic element into Farrell measures of technical efficiency as calculated via linear programming techniques. Specifically, a bootstrap of the original efficiency scores is performed to derive confidence intervals and a measure of bias for the scores. The bootstrap generates these measures of statistical precision for the nonstochastic efficiency measures by using computational power to derive empirical distributions for the efficiency measures.     

Who consults investment analysts?

This paper shows that the questions: Who consults investment analysts? and Who goes to the El Farol bar in Santa Fe? are similar. Thus, investors use a mixed optimal strategy. The demand for consulting services is also characterized.Received: 25 September 2002, Accepted: 26 May 2003, JEL Classification: D81, C70Jacob Paroush: The author is grateful to Yaw Nyarko, Yigal Milchtaich and an anonymous referee for helpful comments and suggestions.     

Effective participative decision making: A joint responsibility for success

Much of the current research on participative decision making focuses on the increasing need for broad-based decision-making systems, on the different outcomes associated with different forms of participation, or on the problems associated with poorly managed participative decision-making systems. This article considers the responsibilities of employees who participate in organizational decision making and the responsibilities of employers who expect to share decision-making tasks. A Bill of Responsibilities for Employees and a Bill of Responsibilities for Employers are presented. Pitfalls associated with neglecting these responsibilities are discussed.     

Das maximale signifikanzniveau des Tests: “LehneH o ab,wennk untern gegebenen tests zur ablehnung führen”

Summary On one sample space there aren tests with critical regionsK ₁ and levels of significance _i ,i=1, ...,n (resp.n eventsK _i in a probability space with probabilities not greater than _i ,i=1, ...,n). In this paper we calculate the smallest upper bound of the level of significance of the test reject the hypothesis, if at leastk among the,n tests do so (resp. of the probability of the event at leastk among then events are realized). By the way, we will show, that this smallest upper bound does not change, if we replace at leastk by exactlyk.     

Contradictions in human resource commitment and employment-at-will policies

Employment in the U.S. appears to be subject to two broad, conflicting influences. Foreign competition and declining productivity have resulted in the suggested development of a commitment strategy in employment relations. Current administration policy towards employment, it is argued, combined with prevailing, notions of employment-at-will are in essential, tension with international standards of employment security and the content of the new industrial relations policies advocated by human resource practitioners and researchers.     

Employee-initiated defamation lawsuits: Organizational responses and dilemmas

The fast-growing category of defamation lawsuits in the United States involves actions by employees against their employers. Over the last decade, the courts have increasingly ruled in favor of the employee plaintiffs, thus creating an employee's right to reputation. This article identifies a variety of responses undertaken by organizations to reduce their legal liability and lessen the likelihood of employee defamation lawsuits. We argue that while organizational actions to reduce their legal liability may appear rational, such responses may also be creating situations in which employers, employees, and the public may be the unintended victims of a law without justice. The article concludes with a discussion of balancing the freedom necessary for managers to communicate about employees and the fairness of that communication.     

State competition in higher education: A race to the top,or a race to the bottom?

How does competition affect higher education? This paper explores this question for public and private universities. Theory indicates that competition can push higher education policy in one of two different directions. On the one hand, competition may increase spending. For states, this would occur if states treat higher education as developmental; for private universities this would occur if they view spending as a means to attract students and prestige. On the other hand, competition may decrease spending if states treat higher education spending as redistributive, and competition may decrease spending by private schools if lower spending enhances their ability to attract students with low tuition. To determine which of these perspectives is most valid, we examine higher education policy choices in the 1980s and 1990s. We find that states appear to act as if higher education funding is redistributive while private schools appear to compete more on the basis of tuition than spending. These results demonstrate the important effects competition and governance structure have on higher education.Received: August 2001, Accepted: May 2002, JEL Classification: I2, I22, H72, I3     

On estimating the variance of a finite population

Summary Observing that the estimator for a finite population variance as recommended byLiu [1974a, b] can sometimes become negative, we suggest a few non-negative alternative estimators and note some of their properties. UnlikeLiu we follow the conventional Bayesian approach to get another estimator with an optimal property of uniform admissibility.This paper, however, was prepared when the author worked in the Department of Economic Statistics, University of Sydney.     

DEA and Activity Planning under Asymmetric Information

The productivity analysis literature has traditionally focused on the evaluation of past performances. In this paper, we consider the post productivity analysis problem of deciding which production plans to choose in the future given information from a productivity analysis. In particular, we demonstrate that Data Envelopment Analysis (DEA) has an important role to play in the reallocation game following a normal productivity analysis. DEA estimates reduce the information rents an agent can extract by claiming high costs for the least reduced or most expanded activity. We also examine how to optimally combine DEA estimates with other information in a planning context, including preference information, ex-ante cost reports and ex-post cost data.     

Financial reforms and regional investment conflicts in China: A game-theoretic analysis

In the transition from a command to a market economy, macroeconomic stabilization poses a grave problem facing the reform governments. A distinct feature of China's economic fluctuations in the post-1979 period has been its soft-constraint competition. A two-region game theoretical model is developed in this paper. We find that monetary decentralization in the earlier stage of economic liberalization takes the inflation and fiscal deficits out of the control of the central monetary authorities. The prospective financial reforms will subject local governments' investment drives to the indirect regulations of monetary policy; but by strengthening monetary restraints, will result in massive borrowing from the domestic, or perhaps more likely, the international financial market to finance government deficits, and hence a large build-up in the stock of debts.     

Über eine Variante der empirischen Verteilungsfunktion

Summary If ₁, ₂,..., _n and ₁, ₂,..., _–1 are two ordered samples from a population with continuous distribution functionF(x), then the points ( _r ,r/n),r=1, 2,..., n–1 provide a better approximation ofF(x) than the points ( _r ,r/n),r=1, 2,..., n, in the following sense:A maximal upper deviation and a maximal lower deviation of more theny have — contrary to the points ( _r ,r/n) — equal probability for anyy0, if we deal with the points ( _r ,r/n). This probability is at least for ally in the interval , 1 less than the probability for a maximal upper deviation of more thany in the case of the points ( _r ,r/n). This is shown by a comparison of the Smirnow-Birnbaum-Tingey — formula with an analogous formula for the maximal one-sided deviations of the points( _r ,r/n).     

Optimality of block designs with variable block sizes and random block effects

We consider the simple block model with random block effects, the block effects having variance _b ² =²;, with ² the variance of the errors. It is assumed that the experimenter can vary the sizes of the blocks. The universal optimality of certain designs for all over all designs with the same number of blocks and the same number of observations is shown. It is of interest to note that if Balanced Incomplete Block Designs compete, then they perform equally well for =0 and for =, i.e. in the one way classification model and in the simple block model with fixed block effects, but they perform worse for every (0, ).The result is, however, theoretical in nature. It treats a situation which is not very likely to happen in practice. The interest lies in the fact that it provides a counterexample to a conjecture on optimality of designs in mixed models.     

Die asymptotische Verteilung des Prognosefehlers bei Prognosen mit Hilfe eines dynamischen ökonometrischen Modells höherer als erster Ordnung

Zusammenfassung In dieser Arbeit wird die asymptotische Verteilung des Prognosefehlers, wie er sich im Rahmen einer dynamischen Simulation eines allgemeinen autoregressiven ökonometrischen Modells der Ordnungp (einschließlich verzögerter exogener Variabler der Ordnungq) ergibt, abgeleitet. Daran anschließend werden einige Fragestellungen, die damit in unmittelbarem Zusammenhang stehen, diskutiert: Die Frage der relativen Effizienz der Prognoseschätzung, basierend auf der unrestricted- bzw. der derived reduced form, die Verwendung der asymptotischen Verteilung des Prognosefehlers für einen predictive test des Modells. Außerdem werden asymptotische simultane Prognoseintervalle abgeleitet.

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Summary The asymptotic distribution of the forecast error in the dynamic simulation of a higher than first order linear dynamic econometric model is derived and related topics are discussed.

     

r-te Momente von Punktprozessen

Zusammenfassung {X (t): tR ⁺} sei ein Punktprozeß,H (x) eine konvexe nicht-negative Funktion. Mit Hilfe der bedingten Wahrscheinlichkeitenp _n (t) für genaun Ereignisse (Punkte) im Zeitpunkt punktt unter der Bedingung, daß im Zeitpunktt mindestens ein Ereignis eintritt, wird eine Beziehung formuliert, die für die Existenz des ErwartungswertesE (H (X (t ₀))) notwendig ist. Hat der Punktprozeß unabhängige Zuwächse, und erfüllt die FunktionH (x) einige weitere Bedingungen, so ist die angegebene Beziehung auch hinreichend für die Existenz dieses Erwartungswertes. Für Punktprozesse mit unabhängigen Zuwächsen ergibt sich als unmittelbare Anwendung dieser Aussagen eine notwendige und hinreichende Bedingung für die Existenz vonE X (t ₀) ^r für reellesr1.

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Summary Let {X (t): tR ⁺} be a point process andH (x) a convex non-negative function. Using the conditional probabilitiesp _n (t) thatn events (points) occur at timet given that at least one event occurs att a condition is formulated which is necessary for the existence ofE (H (X (t ₀))). This condition is sufficient, too, if the point process has independent increments and the functionH (x) fulfils some further conditions. Using these statements one gets a necessary and sufficient condition for the existence ofE X (t ₀) ^r for realr1.

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Herrn ProfessorWeissinger zum 65. Geburtstag am 12. Mai 1978 gewidmet     

On UMV-EStimators in survey sampling

Summary The existence of uniformly minimal variance estimators in the class of all linear unbiased estimators of the population total is discussed. Some remarks are given on the concept of necessary bestness.

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Zusammenfassung Es wird die Existenz von Schätzungen mit gleichmäßig minimaler Varianz in der Klasse aller linearen erwartungstreuen Schätzungen des Populationstotales besprochen. Einige Bemerkungen werden zum Begriffi necessary bestness gemacht.

     

Two-dimensional Bernstein polynomial density estimators

A Bernstein polynomial estimator for f_nN(x, y) for an unknown probability density functionf(x, y) concentrated on the triangle ={(x, y): 0x, y<1,x+y<1} or on the square =(x, y):0 x, y 1 is developed. As a measure of quality the exact order of magnitude for the pointwise mean squared error is established. It is seen that the quality of these Bernstein polynomial estimators is comparable with the quality of the so-called kernel estimators. Further for such estimators uniform weak consistency results and central limit theorems are developed.     

Ulteriori contributi a un problema di Leo Moser

Si dimostrano condizioni necessarie e sufficienti relative a punti di Kuhn-Tucker per il «problema dei dadi truccati» e viene proposto un algoritmo per la ricerca di tali punti, tramite una successione di programmi lineari.

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The author's version of the «loaded dice problem» asks for x₁ to be maximum subject tox0 andx ^T H _i x1, whereH _i is the Hankel matrix of the (2n–1)-dimensional unity vectore ⁱ (i=1,..., 2n–1).Proofs are given here about necessary and sufficient conditions for Kuhn-Tucker points, together with an algorithm for finding them by means of a sequence of linear programs.

     

ICT Investment, Productivity and Efficiency: Evidence at Firm Level Using a Stochastic Frontier Approach

We analyze the determinants of ICT investment and the impact of information technology on productivity and efficiency on a representative sample of small and medium sized Italian firms. In order to test the most relevant theoretical predictions from the ICT literature we evaluate the impact of investment in software, hardware and telecommunications of these firms on a series of intermediate variables and on productivity. Among intermediate variables we consider the demand for skilled workers, the introduction of new products and processes and the rate of capacity utilization. Among productivity measures we include total factor productivity, the productivity of labor, and the distance from the best practice by using a stochastic frontier approach. Our results show that the effect of ICT investment on firm efficiency can be more clearly detected at firm level data by decomposing it into software and telecommunications investment. We find that telecommunications investment positively affects the creation of new products and processes, while software investment increases the demand for skilled workers, average labor productivity and proximity to the optimal production frontier. We interpret these results by arguing that ICT investment modifies the trade-off between scale and scope economies. While software investment increases the scale of firm operations, telecommunications investment creates a flexibility option easing the switch from a Fordist to a flexible network productive model in which products and processes are more frequently adapted to satisfy consumers taste for variety.