A Study of Expansions of Posterior Distributions

Johnson (1970 Johnson , R. ( 1970 ). Asymptotic expansions associated with posterior distributions . Ann. Math. Statist. 41 : 851 – 864 .[Crossref] , [Google Scholar]) obtained expansions for marginal posterior distributions through Taylor expansions. Here, the posterior expansion is expressed in terms of the likelihood and the prior together with their derivatives. Recently, Weng (2010 Weng , R. C. ( 2010 ). A Bayesian Edgeworth expansion by Stein's Identity . Bayesian Anal. 5 ( 4 ): 741 – 764 .[Crossref], [Web of Science ®] , [Google Scholar]) used a version of Stein's identity to derive a Bayesian Edgeworth expansion, expressed by posterior moments. Since the pivots used in these two articles are the same, it is of interest to compare these two expansions.

We found that our O(t ^?1/2) term agrees with Johnson's arithmetically, but the O(t ^?1) term does not. The simulations confirmed this finding and revealed that our O(t ^?1) term gives better performance than Johnson's.     

Robust and nonparametric subset selection procedures

Subset selection procedures based on ranks have been investigated by a number of authors previously. Their methods are based on ranking the samples from all the populations jointly. However, as was pointed out by Rizvi and Woodworth (1970), the procedures they proposed cannot control the probability of a correct selection over the entire parameter space. In this paper, we propose a subset selection procedure based on pairwise rather than joint ranking of the samples. It is shown that this procedure controls the probability of a correct selection over the entire parameter space. It is also shown that the Pitman efficiency of this nonparametric procedure relative to the multivariate t procedure of Gupta (1956, 1965) is the same as the Pitman efficiency of the Mann-Whitney-Wilcoxon test relative to the t-test.     

On a sequential subset selection procedure for the least probable multinomial cell

This paper studies a sequential procedure R for selecting a random size subset that contains the multinomial cell which has the smallest cell probability. The stopping rule of the proposed procedure R is the composite of the stopping rules of curtailed sampling, inverse sampling, and the Ramey-Alam sampling. A reslut on the worst configuration is shown and it is employed in computing the procedure parameters that guarantee certain probability requirements. Tables of these procedure parameters, the corresponding probability of correct selection, the expected sample size, and the expected subset size are given for comparison purpose.     

Scheduling Problems in a Practical Allocation Model

A parallel computational model is defined which addresses I/O contention,latency, and pipe-lined message passing between tasks allocated to differentprocessors. The model can be used for parallel task-allocation on either anetwork of workstations or on a multi-stage inter-connected parallel machine.To study performance bounds more closely, basic properties are developed forwhen the precedence constraints form a directed tree. It is shown that theproblem of optimally scheduling a directed one-level precedence tree on anunlimited number of identical processors in this model is NP-hard. Theproblem of scheduling a directed two-level precedence tree is also shown tobe NP-hard even when the system latency is zero. An approximation algorithm is then presented for scheduling directedone-level task trees on an unlimited number of processors with anapproximation ratio of 3. Simulation results show that this algorithm is, infact, much faster than its worst-case performance bound. Better simulationresults are obtained by improving our approximation algorithm usingheusistics. Restricting the problem to the case of equal task executiontimes, a linear-time algorithm is presented to find an optimal schedule.     

Do Different Infant Smiles Reflect Different Positive Emotions?

Different types of infant smiles in the family of positive emotions were investigated during two mother-infant games: peekaboo and tickle. There were 27 6-month-old infants and 28 12-month-olds. Infant smiles were coded as simple (lip corner retraction only), Duchenne (simple plus cheek raising), play (simple plus jaw drop), and duplay (simple plus cheek raise and jaw drop). Results show that each type of smile has a systematic pattern of association with the game (peekaboo or tickle), component (setup or climax), trial (six trials for each game), and the direction of the infant's gaze. No significant age differences were found. We conclude that when smiling, infants may experience qualitatively different kinds of enjoyment during these two games: enjoyment of readiness to engage in play (simple smiles while gazing at mother during peekaboo), enjoyment of relief (simple smiles while gazing away from mother after being tickled), enjoyment of participation and agency (Duchenne smiles with gaze at mother during the climax of early tickle game trials), enjoyment of escape (Duchenne smiles while gazing away during tickle climax), and enjoyment of build-up (duplay smiles during the climax of later trials). These findings show that the same facial action, smiling, can reflect different positive emotions depending upon cooccurring facial actions and the dynamics of the social process, and that the positive emotional experience of infants as young as six months is more complex than previously reported.     

Semiparametric estimation for seasonal long-memory time series using generalized exponential models

We consider a generalized exponential (GEXP) model in the frequency domain for modeling seasonal long-memory time series. This model generalizes the fractional exponential (FEXP) model [Beran, J., 1993. Fitting long-memory models by generalized linear regression. Biometrika 80, 817–822] to allow the singularity in the spectral density occurring at an arbitrary frequency for modeling persistent seasonality and business cycles. Moreover, the short-memory structure of this model is characterized by the Bloomfield [1973. An exponential model for the spectrum of a scalar time series. Biometrika 60, 217–226] model, which has a fairly flexible semiparametric form. The proposed model includes fractionally integrated processes, Bloomfield models, FEXP models as well as GARMA models [Gray, H.L., Zhang, N.-F., Woodward, W.A., 1989. On generalized fractional processes. J. Time Ser. Anal. 10, 233–257] as special cases. We develop a simple regression method for estimating the seasonal long-memory parameter. The asymptotic bias and variance of the corresponding long-memory estimator are derived. Our methodology is applied to a sunspot data set and an Internet traffic data set for illustration.     

A note on fault-free mutually independent Hamiltonian cycles in hypercubes with faulty edges

In the paper “Fault-free Mutually Independent Hamiltonian Cycles in Hypercubes with Faulty Edges” (J. Comb. Optim. 13:153–162, 2007), the authors claimed that an n-dimensional hypercube can be embedded with (n−1−f)-mutually independent Hamiltonian cycles when f≤n−2 faulty edges may occur accidentally. However, there are two mistakes in their proof. In this paper, we give examples to explain why the proof is deficient. Then we present a correct proof. This work was supported in part by the National Science Council of the Republic of China under Contract NSC 95-2221-E-233-002.     

基于公平理论探讨服务补救质量影响的实证研究——来自中国电信服务行业的证据

企业与客户交易时并不会一帆风顺,当客户面对交易过程中出现的故障时,不同服务补救措施会如何对客户感知、满意度和信任度产生影响?本文区别于以往实验或准实验法为主的定性或定量研究,引入组织行为学的公平理论,采取真实客户服务数据,基于不同客户类型深入探讨服务补救质量对客户满意、客户信任和客户忠诚的影响.实证研究发现,服务补救质量对感知价值、满意和信任均会产生正向作用;大客户对服务补救过程中的"互动公平"最为重视,公众客户更为强调"结果公平"的影响.这就告诉服务型企业应如何采取补救措施,大客户看重过程,一般客户更看重结果.本文从理论和实践两方面为服务补救领域的研究提供了有力证据.     

Social Acceleration Theory and the Self

In recent years, there has been a rapidly growing body of work in the social sciences that underscores the prevalence of the phenomenon of ‘social acceleration'—the speeding up of social life— in many parts of the Western world. Although research on social acceleration has tended to analyze the phenomenon on a social‐structural level, there is also a need to investigate how social acceleration has ‘ramifications for the socially dominant forms of self‐relation’. One way to gain a more in‐depth understanding of this facet of social acceleration is to investigate the speeding up of social life through the prism of the self. The central argument of this article is that there are at least five images of the self which can be associated with the social acceleration phenomenon: (1) the ‘detached’ self, (2) the ‘reflexive’ self, (3) the ‘reinventive’ self, (4) the ‘stationary’ self and (5) the ‘decelerating’ self. By explaining how these kinds of self relate to the speeding up process, we seek to advance a more nuanced and sophisticated theory of social acceleration, which captures some of the complexities and paradoxes that the phenomenon involves.     

Partition testing in dose-response studies with multiple endpoints

Dose-response studies with multiple endpoints can be formulated as closed testing or partition testing problems. When the endpoints are primary and secondary, whether the order in which the doses are to be tested is pre-determined or sample determined lead to different partitioning of the parameter space corresponding to the null hypotheses to be tested. We use the case of two doses and two endpoints to illustrate how to apply the partitioning principle to construct multiple tests that control the appropriate error rate. Graphical representation can be useful in visualizing the decision process.