Transportnetzgestaltung für Paketdienstleister

Zusammenfassung  In diesem Beitrag entwickeln wir ein Hub-Location-Modell zur Bestimmung der Standorte von Hubs aus einer gegebenen Menge von Depots. Mit einer stufenf?rmigen Transportkostenfunktion erhalten wir die effiziente Kombination von Fahrzeugen bestimmter Typen von einem oder mehreren Verkehrstr?gern. Ferner berücksichtigen wir direkte Transporte und die Regellaufzeit der einzelnen Transporte. In Anlehnung an ein vorhandenes Transportnetz eines Paketdienstleisters demonstrieren wir die Anwendbarkeit des Ansatzes.

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Transportation network design for parcel service provider

Summary  In this paper we develop a hub location model to determine the locations of hubs from a given set of depots. Applying a stepwise transport cost function, we get the efficient combination of certain types of vehicles by one or more modes of transport. Furthermore, we consider direct transports and a maximum transit time. Based on an existing transportation network of a parcel service provider, the applicability of the model is shown.

     

Life Quality measures of smoking

The cost of smoking has three principal dimensions: money, reduced life expectancy, and diminished health. Each component can be quantified; all have an influence on the quality and duration of life. The combined influence can be evaluated using an aggregated social indicator, such as the Life Quality Index. It can be expressed in various ways, e.g. as an equivalent move to a nation or to a time with a lower level of the LQI, as an equivalent economic loss, or as an equivalent loss of life expectancy. To illustrate, the analysis is applied to Danish data on smoking; the cost for a typical pack-a-day habit is equivalent to a 57% reduction in personal income, 8.6 years loss of life expectancy, or a 4% drop in the Life Quality Index. These measures underscore the seriousness of smoking as a health hazard.     

ESTIMATION OF THE CONDITIONAL PROBABILITY OF TUBERCULOSIS GIVEN THE RESPONSE OF A MANTOUX TEST

For the planning of community tuberculosis, prophylaxis one must know the prevalence of tuberculosis (TB) infection as a function of response to the Mantoux intradermal tuberculin test; the standard test for indicating Mycobacterium TB infection. The skin induration size used to select individuals for prophylaxis must be chosen carefully, in view of the costs associated with carrying out and supervising such prophylaxis. The Mantoux test was used to obtain measurements on adolescents in metropolitan Victoria and on a small sample of adolescents with clinical TB. These data are employed to obtain estimates and to construct upper confidence bounds for the conditional probability of TB infection, given the level of Mantoux response. Two conservative methods are presented; one is ‘nonparametric’, the other ‘semiparametric’. The analyses indicate that for responses up to and including 13 mm, the probability of TB infection is less than.07 with ninety-five percent confidence.     

Developer autonomy in the FreeBSD open source project

Delegation of authority is the basic approach to coordination of work in FreeBSD, an open source software (OSS) project that develops and maintains an operating system. This essay combines a software engineering perspective with a knowledge creation perspective to discuss three central mechanisms in FreeBSD: (1) motivation, (2) quality control by frequent building, and (3) bugfixing by parallel debugging. It is argued that frequent building is the project’s key coordinating mechanism, and that build breakdowns play a constructive role in the processes of knowledge creation in FreeBSD.     

Regret aversion and the reluctance to exchange lottery tickets

The current research finds that people are willing to forego a direct material gain, if that protects them from future regrets. In two experiments participants endowed with a lottery ticket were offered to exchange their ticket for another ticket from the same lottery. Even though they could receive a bonus for exchanging, many participants chose not to do so. Experiment 1 finds that a manipulation that prevented the anticipation of regret by offering the ticket in a sealed envelope made more participants exchange their ticket. Experiment 2 finds that an increased potential of regret over not-exchanging made more participants exchange as well. In both experiments the effect of the manipulation on choices is mediated by anticipated regret. The experiments show that people are willing to forego a material gain to prevent future regrets and that the reluctance to exchange lottery tickets is (partly) caused by regret aversion.     

Demographic Transitions and Changes in the Living Arrangements of Children: The Netherlands 1850–2010

The transformation of Europe’s demographic regime over the past two centuries has led to considerable changes in the living arrangements of children. We study long-term changes, making use of three datasets covering the living arrangements of children born between 1850 and 1993 in the Netherlands: a historical national sample of children born between 1850 and 1922, a retrospective survey covering children born between 1923 and 1985, and data from the national population registry relating to children born between 1986 and 1993. We describe the changes in terms of whether fathers, mothers, and stepparents lived with these children at birth and at age 15. We observe a massive increase in the percentage of children growing up in a complete family between the 1850–1879 cohort and the mid-twentieth century cohorts and a return to nineteenth-century conditions in the most recent birth cohort. Time spent in a complete family increased continuously from the mid-nineteenth century on, to decrease again from the 1960s on.