A Recourse Stochastic Goal Programming Approach for the Multi‐objective Stochastic Vehicle Routing Problem

This paper addresses a multi‐objective stochastic vehicle routing problem where several conflicting objectives such as the travel time, the number of vehicles in use and the probability of an accident are simultaneously minimized. We suppose that demands and travel durations are of a stochastic nature. In order to build a certainty equivalent program to the multi‐objective stochastic vehicle routing problem, we propose a solution strategy based on a recourse approach, a chance‐constrained approach and a goal‐programming approach. The resulting certainty equivalent program is solved to optimality using CPLEX. Copyright © 2016 John Wiley & Sons, Ltd.     

An interactive multiobjective programming approach to combinatorial data analysis

Combinatorial optimization problems in the social and behavioral sciences are frequently associated with a variety of alternative objective criteria. Multiobjective programming is an operations research methodology that enables the quantitative analyst to investigate tradeoffs among relevant objective criteria. In this paper, we describe an interactive procedure for multiobjective asymmetric unidimensional seriation problems. This procedure uses a dynamic-programming algorithm to partially generate the efficient set of sequences for small to medium-sized problems, and a multioperation heuristic to estimate the efficient set for larger problems. The interactive multiobjective procedure is applied to an empirical data set from the psychometric literature. We conclude with a discussion of other potential areas of application in combinatorial data analysis.Stephanie Stahl is a freelance writer and editor. She can be reached via e-mail at s-stahl@worldnet.att.net.     

A review of multiobjective programming and its application in quantitative psychology

Multiobjective programming, a technique for solving mathematical optimization problems with multiple conflicting objectives, has received increasing attention among researchers in various academic disciplines. A summary of multiobjective programming techniques and a review of their applications in quantitative psychology are provided.     

Reaction Time Analysis of Two Types of Motor Preparation for Speech Articulation: Action as a Sequence of Chunks

Reaction time (RT) prior to speech articulation increased as a function of response complexity. The RT findings formed 2 patterns, each of which was a different Response Complexity × Paradigm (choice RT vs. simple RT) interaction. That result extends previous findings from manual button-pressing tasks (S. T. Klapp, 1995) to a different action modality. Two different types of response programming, INT and SEQ, are assumed in the interpretation. Whereas INT can be identified with response programming within a word, SEQ fits a different interpretation related to timing of onsets of speech units. A critical assumption is that a long response is represented as a sequence of chunks; that organization is subject to manipulation. New findings suggest some modifications of the previous theory.     

Differential Method of Characterizing Gait Strategies From Step Lengths and Frequencies: Strategy of Velocity Modulation

The differential method consists of the analysis of the variation of gait parameters length, frequency, and velocity with respect to their mean values, respectively, ΔL = L — L_m , Δf = f — f_m , and Δv = v – v_m , where L_m , f_m , and v_m represent the mean values of those parameters. Assuming that the strategy of modulation of velocity implies that L and f are functions of v and that statistical analyses of ratios ΔL/Δv and Δf/Δv have established that there is a very significant linear correlation, close to 1, between those ratios, the mathematical procedure allows one to determine the equation of step length, L = a · f + b · v + K, where a and b are the slope and the intercept of the linear regression and K is close to L_m . The equation was experimentally tested on 140 gait sequences performed by 6 participants and for gait velocities ranging from 0.6 to 2.2 m/s and was found to be very representative of all individual values. The differential method provides another way of using the derivative of velocity, v = L·f, to characterize the strategy of velocity modulation, which then permits one to determine the linear equation of velocity, v = f · L_m + L · f_m — L_m · f_m , and to show that the respective parts played by each parameter in the progression velocity are approximately equal. The author establishes the uniqueness of the different linear adjustments and discusses the differential method's own modes of use, that is, interindividually or globally.     

Spiritual Need Four: Opportunities to Be Served and to Share with Others

SUMMARY

Older adults have unique opportunities to be served and to share with others through groups and individual relationships and programs in religious congregations. Where programs and senior centers with public funding can provide only for physical, emotional, and social needs, religious congregations can be more wholistic and provide for the spiritual needs as well. This chapter offers further discussion of planning that will facilitate program development for the whole person.     

The Effect of Interpolated Motor Activities in Short-Term Motor Memory

This experiment examined the effect of an interpolated motor response on short-term retention of a blind positioning movement. The interpolated response was varied in degree of similarity to the response length (± 25, ± 50, and ± 100 mm.), in number of repetitions (0, 1, or 5), and in temporal position (immediate or delayed), with a retention interval of 25 sec. Absolute error was not affected but a systematic change in response bias due to interpolated motor activity was found. When an interpolated response was longer than the response length, the tendency to undershoot decreased. The defay of the interpolated response was relatively more important than the number of repetitions in producing a positive shift in response bias. These results are interpreted as evidence for a form of interference in short-term motor memory.     

The influence of extrafoveal emotional faces on prosaccade latencies

Across three experiments we sought to determine whether extrafoveally presented emotional faces are processed sufficiently rapidly to influence saccade programming. Two rectangular targets containing a neutral and an emotional face were presented either side of a central fixation cross. Participants made prosaccades towards an abrupt luminosity change to the border of one of the rectangles. The faces appeared 150 ms before or simultaneously with the cue. Saccades were faster towards cued rectangles containing emotional compared to neutral faces even when the rectangles were positioned 12 degrees from the fixation cross. When faces were inverted, the facilitative effect of emotion only emerged in the ?150 ms SOA condition, possibly reflecting a shift from configural to featural face processing. Together the results suggest that the human brain is highly specialized for processing emotional information and responds very rapidly to the brief presentation of expressive faces, even when these are located outside foveal vision.     

Planning and Executing Simple Movements: Contributions of Relative-Time and Overall-Duration Specification

In 3 experiments, the authors used a precuing protocol to examine the nature and cost of programming and the subsequent reprogramming of a movement's relative time and overall duration. Initial programming followed a fixed-order specification; knowledge of the necessary relative time was required before information regarding overall duration could be used in a manner that expedited response planning. In the case of reprogramming, however, when a modification had to be made in either the relative time or overall duration of the anticipated and already-prepared response, performers chose to completely reprogram the entire response. Complete reprogramming occurred even when the performer had correctly prepared the higher order relative-time component and only had to modify the overall duration of the movement. The data indicate that organizing movement timing before movement initiation is accomplished in a fundamentally different manner depending on whether the movement is being initially compiled or modified.     

Predictive Mechanisms Control Grip Force after Impact in Self-Triggered Perturbations

ABSTRACT

Impulsive loadings during object grasping are common in everyday life. In predictable conditions, the grip force (GF) increases before the impact to anticipate the perturbation and reaches a maximum after the perturbation. In the present study, the authors addressed the predictive or reactive nature of this late GF component. The load of a handheld object was briskly increased by dropping a mass attached to the object (impact trials). The drop was self-induced, but for one third of the trials, the mechanism was blocked and no impact occurred (blank trials). Evidence that the late GF component is programmed as a predictive action emerged from a systematic comparison between impact and blank trials. The authors conclude that the GF increase occurring after a predictable impulsive loading is essentially of a predictive nature.