Record allocation for minimizing seek delay

Given a set of variable length records and their access probabilities, we address the problem of allocating these records on a linear storage device so as to minimize the expected seek time. A partial characterization of the optimal arrangement is given and the general problem of finding an optimal solution is shown to be NP-hard. Next, two heuristics are considered and performance bounds are derived for them. Although these bounds are not very encouraging, both heuristics are found to perform well in practice.     

Gas holdup and aerated power consumption in mechanically stirred tanks

Gas holdup and mechanical power consumption were measured in aerated aqueous nonelectrolyte and electrolyte systems. The experiments were performed in 0.4 m diameter cylindrical flat-bottomed and hemispherical-bottomed tanks. Standard six-blade turbine (D/T = 0.225, 0.325, 0.45) and four-blade paddle (D/T = 0.225, 0.325) were used over a wide range of gas sparging rate and power dissipation. A semiempirical correlation for holdup with dimensionless groups, i.e. impeller Weber number, aeration number and ratio of impeller diameter to tank diameter has been developed; however, this correlation did not fit the electrolyte solution data. The power consumption data of both the impeller types and tank bottom types were found to fit satisfactorily the Michel-Miller correlation with 20% accuracy.     

Mixed formulation finite elements for mindlin theory plate bending

Two new finite elements are developed for the Mindlin theory plate bending problem. The formulation is based on the modified Hellinger-Reissner principle with independent transverse shear strains. Numerical examples indicate that, with properly assumed transverse shear strains, these new elements designated as PLAT8 and PLAT8H do not exhibit locking effect even for very thin plates.     

A laboratory evaluation of a low cost motor vehicle crash recorder

The need for a low cost vehicle crash recorder that would provide a measure of crash severity for a large number of vehicle crashes has long been recognized. A simple viscous damped mechanical crash recorder has been developed which measures vehicle velocity change, ΔV, as the recorded parameter. Prototypes have been evaluated in a laboratory test program which subjected the recorders to a series of tests under various crash speeds and durations that might be expected in the real world. The results of this evaluation indicate that the prototype, low cost crash recorders have great potential for large scale application in motor vehicles.     

Hyperreactivity, muricide, and intraspecific aggression in the rat produced by infusion of local anesthetic into the lateral septum or surroundng areas.

Intracranial infusions of a local anesthetic (lidocaine, 2%) were made bilaterally (4 μl over 20 min) through permanently implanted cannulas ending in the lateral septum or adjacent areas in 167 male hooded rats. Increases in irritability and reactivity to the experimenter, muricide, and intermale aggression were produced by injections into the lateral septum and the region ventral to it. The increase in reactivity and interanimal aggression occurred in varying degrees and were independent of one another, but intermale aggression occurred only in Ss showing muricide. The most effective site for eliciting the entire spectrum of aggressive behaviors was the region ventral to the anterior septum. The region ventral to the posterior septum tended to produce a high incidence of muricide with only modest increases in reactivity. No changes in behavior were noted with infusions into the medial septum or the medial forebrain bundle/lateral preoptic area ventrolateral to the septum. It is suggested that the hyperreactivity and irritability may be related to hyperdefensiveness and that muricide and intermale aggression are points on a continuum of interanimal aggressiveness. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Centralized Scheduling and Priority Implementation Heuristics for a Dynamic Job Shop Model

The problem considered is the scheduling of a job shop with job due dates, intermittent job arrivals, and statistical processing times. Centralized scheduling uses a sequence of static problems for generating priorities at review times. A multi-pass heuristic program, which has proven effective in earlier research, is applied to the up-dated static scheduling problem at each review time. A procedure is proposed for implementing priorities on the shop floor between review times. The procedure is expressly designed to integrate the scheduling of newly arriving jobs to modify the schedule. In simulation experiments using tardiness statistics for evaluation, centralized scheduling and the proposed implementation procedure proved to be an extremely effective combination. Comparison with another procedure that gives the centralized schedule precedence over new arrivals indicates the importance of the implementation procedure when periodic centralized scheduling is used in a dynamic situation.     

Self-presentation dynamics on overt integrity tests: Experimental studies of the Reid Report.

Three experiments examined impression-management responses to the Reid Report Integrity Attitude Inventory. Ss encouraged to score high on the honesty test attained higher scores than a control group, but no higher than a group of job applicants. Study 2 offered money for high scores, and provided information to use concerning the 1st, 2nd, or both factors of the Reid Report. Ss in the 3 information conditions scored higher than those in a control condition, but again were no higher than job applicants. In a 3rd study, Ss were asked to respond to the Reid Report and to several other measures as if they seriously wanted a job. After the test, each subject was overpaid for the participation. Reid Report scores were significantly correlated with returning vs retaining the money. These results suggest that integrity tests possess predictive validity despite some impression-management response distortion. Relations with other personality measures also are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How many subjects to screen? A practical procedure for estimating multivariate normal probabilities for correlated variables.

Suggests a practical procedure for estimating the number of Ss that need to be screened to obtain a sample of fixed size that meets multiple correlated criteria. The procedure is based on the fact that least squares regression provides a good quadratic fit for Monte Carlo estimates of multivariate probabilities when they are plotted as a function of mean pairwise correlations (r) for the criterion variables. The equations given here can be used to predict selected 3- to 5-variable joint probabilities with reasonable accuracy as long as pairwise correlations for the selection criteria range from .10 to .90. (PsycINFO Database Record (c) 2010 APA, all rights reserved)