An evaluation of the tandem configuration automated guided vehicle system

The performance of a tandem automated guided vehicle (AGV) system is compared with that of conventional AGV track systems. In the tandem system the track is divided into non-overlapping, single-vehicle closed loops. Using simulation it is shown that, because of trips requiring delivery across loops, the tandem system has a higher expected travel time per load and thus a greater average time in system. When the loads are delivered within the original loop only, the tandem system has a lower average time in system than in conventional systems, although the difference is modest. Track layout appears to influence the average time in system much more than docs the dispatching rule invoked. The success of the tandem system is highly dependent on approximately even AGV utilization, which may be difficult to obtain in practice.     

The Association between Child Abuse and Attempted Suicide

Summary A recent survey by the authors has demonstrated that attemptedsuicide is common in parents, particularly mothers, who abusetheir children. However, the nature of the association betweenchild abuse and attempted suicide is complicated. Here somepossible types of association are suggested. In management ofchild abuse, special note should be taken of a history of attemptedsuicide in the parents because, in some cases, it suggests apoor prognosis. Similarly, young children of parents who attemptsuicide should be assessed in case they are at risk of abuse.     

Love and Personal Relationships: Navigating on the Border Between the Ideal and the Real

In the psychological literature, love is often seen as a construct inseparable from that of close, interpersonal relationships. As a result, it has been often assumed that the same motivational factors underlie both phenomena. This often leads researchers to propose that love does not exist in itself—that it is an emotion which stems solely from a need for attachment, fulfillment of reproductive aims, or for social exchange. The popular cultural imagination, however, perceives love as a unique, mysterious, altruistic, ever-lasting bond between two people—a vision of love which is at odds with its supposed psychological origins. We propose that an ideal of love and its enactment in our culture is a result of two intertwining factors. Within the last few centuries, interpersonal relationships and love have replaced religion as islands of existential comfort. Toward this end, lovers project illusory meaning on their partners. The laborious and turbulent process of withdrawing these projections can lead to what many thinkers think "love" is: bestowal of value on another, and consequent respect for, and care for that person, unmotivated by one's own needs, within the context of a real relationship.     

CHARITIES, NO; LOTTERIES, NO; CASH, YES: MAIN EFFECTS AND INTERACTIONS IN A CANADIAN INCENTIVES EXPERIMENT

The effects on response rates to mail surveys of prepaymentcash incentives, charitable donations, and the chance to wina lottery prize are examined in a true experimental design.A survey on environmental issues was conducted during the fallof 1994 among 3,088 households drawn from the Grand River watershedregion of southwestern Ontario, Canada. The 20-cell incentivesexperiment crossed three levels of prepaid monetary cash incentive($2, $5, and $10) with a control group (no cash incentive),plus the offer to make a charitable donation ranging from $2to $10 on behalf of the respondent, or participation in a lotteryfor prizes of $200. The overall response rate to the survey,with three follow-ups, was 70.7 percent with the effects ofthe prepaid cash rewards demonstrated, but not those for thelottery or charitable donations. Logistic regression analysisof response rate supports a main effects model for cash incentivesbut does not support either of two alternative models for maineffects of the lottery and charitable donations or interactions.Further analysis demonstrates a pattern of earlier responseas a result of prepaid incentives. The findings are discussedin terms of their cost-benefit implications and with respectto conceptualizations of respondents' motives for completingmail questionnaires.     

WOMEN AND TARIFFS: TESTING THE GENDER GAP HYPOTHESIS IN A DOWNS-MAYER POLITICAL-ECONOMY MODEL

This paper tests a variant of the standard endogenous tariff model under direct democracy (the Downs-Mayer model) with a gender gap. Specifically, we argue that, if there is a division of economic activity between men and women, and political preferences are affected by one's relationship to the economy, there will be a gender gap in political activity. We test this hypothesis with respect to the effect of political enfranchisement of women on the level of the U.S. tariff. The empirical results strongly support the hypothesis (JEL F4, D7, N4)     

The Welfare State and inequality in the 1980s

A travers une etude surtout du systeme de transferts fiscaux, nous tentons de comprendre le r6le redistributeur de 1'Etat canadien dans les annees contemporaines. Nous faisons l'inventaire des facteurs qui ont module la structure des politiques sociales diveloppee disle debut des annees soixante-dix. Nous evaluons les modes de pression majeurs au cows des dix dernikres annCes en vue d'un changement dans les outils de redistribution, pourensuite mesurer I'impact de ces pressions sur la substance des politiques sociales et surle r d e redistributeur de I'Etat. Dans notre article, nous identifions un mouvement evident vers une plus grande inCgalitC dans les revenus du marche. Cependant, aucune des pressions structurelles ou ideologiques recentes sur I'Etat indique clairement une attCnuation des buts redistributeurs; les reactions ont CtC plut6t multi-directionnelles et ont tendu vers un accroissement. Au milieu des annees quatre-vingts, les changements de politiques n'avaient pas vraiment altC:C I'impact global des systkmes de transferts fiscaux, qui continuaient i neutraliser I'inPgalitC croissante au niveau des revenus du marche, suite i la plus profonde crise Cconomique des dernikres decennies. On est force de conclure quetoute interpretation des politiques sociales comme instruments de stabilite socio-politique a encore force de loi au Canada. This paper examines the redistributive role of the Canadian state in the contemporary period, focussing in particular on the tax-transfer system. The paper surveys the factors that shaped the structure of social policy that had developed by the early 19705, examines the major pressures for change in redistributive instruments during the last ten years, and then analyses the impact of those pressures on both the substance of social policy and the overall redistributive role of the state. The paper identifies clear movement towards greater inequality in market incomes. However, none of the structural or ideological pressures on the state in recent years points unambiguously towards a dramatic retreat from redistributive goals, and the policy response has tended to be multi-directional and for the most part incremental. At the mid-point of the 19805, policy changes had not significantly altered the overall impact of the tax-transfer system, which continued largely to neutralize the growing inequality in market incomes inherent in the deepest economic crisis in over four decades. This evidence suggests that interpretations of social policy as an instrument of social and political stability in Canada retain considerable force.     

UNEMPLOYMENT AND OTHER MEASURES OF LABOR MARKET INEFFICIENCY: A COMPARISON OF U.K. AND U.S. LABOR MARKETS 1931–96

Although unemployment is often used as a measure of labor market inefficiency, economic theory indicates that market inefficiency is determined by both the gap between and the elasticities of supply and demand. Using time series data for the United States and United Kingdom, this article investigates how good the unemployment rate is as a measure of labor market inefficiency by calculating the deadweight loss associated with unemployment rates over time. Results show that the loss arising from unemployment is low across time and countries and that the unemployment rate is often a weak proxy for comparing labor market inefficiency. (JEL J6 )