A survey on pickup and delivery problems

This paper is the first part of a comprehensive survey on pickup and delivery problems. Basically, two problem classes can be distinguished. The first class, discussed in this paper, deals with the transportation of goods from the depot to linehaul customers and from backhaul customers to the depot. This class is denoted as Vehicle Routing Problems with Backhauls (VRPB). Four subtypes can be considered, namely the Vehicle Routing Problem with Clustered Backhauls (VRPCB – all linehauls before backhauls), the Vehicle Routing Problem with Mixed linehauls and Backhauls (VRPMB – any sequence of linehauls and backhauls permitted), the Vehicle Routing Problem with Divisible Delivery and Pickup (VRPDDP – customers demanding delivery and pickup service can be visited twice), and the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP – customers demanding both services have to be visited exactly once). The second class, dealt with in the second part of this survey, refers to all those problems where goods are transported between pickup and delivery locations. These are the Pickup and Delivery Vehicle Routing Problem (PDVRP – unpaired pickup and delivery points), the classical Pickup and Delivery Problem (PDP – paired pickup and delivery points), and the Dial-A-Ride Problem (DARP – passenger transportation between paired pickup and delivery points and user inconvenience taken into consideration). Single as well as multi vehicle versions of the mathematical problem formulations are given for all four VRPB types, the corresponding exact, heuristic, and metaheuristic solution methods are discussed.      

Stürzen vorbeugen

Zusammenfassung  Prophylaxen in der Pflege — Je ?lter Menschen sind, desto h?ufiger passieren Stürze. In der Gruppe der über 70-J?hrigen stürzt mehr als ein Drittel mindestens einmal. Eine der gravierensten Folgen dabei der Oberschenkelhalsbruch: In Deutschland sind es bis zu 100.000 Frakturen pro Jahr. Sturz ist damit ein relevanter Kostenfaktor für das Gesundheitswesen.     

Explaining the American Dream: Telling Chinese Academics What'Liberty and Justice For All'Means Taxes Even an Eager Audience

Abstract . For more than a generation, contemporary mainland Chinese have lived under first a military dictatorship and now a political party dictatorship. How to explain to an eager Chinese academic audience what the American dream of ‘liberty and justice for all’—realized only in part in some areas but approached progressively nearer in others—really means? The U.S. has predominantly a capitalist system but its people are committed to equality of opportunity. It tempers ‘rugged individualism’ by concern for the poor, the handicapped and the unfortunate. It has many serious economic, social and cultural problems but its citizens, drawn from most of the peoples of the world—not the special interest groups trying to benefit at the expense of others—are determined to solve them equitably and rationally. The trade and budget deficits are related to government instrumentalities.     

Kontrakturen

Zusammenfassung  Prophylaxen in der Pflege — Im Vergleich zu T?nzern haben die meisten Menschen „Kontrakturen“, denn Muskeln und B?nder bleiben nur so lange dehnungsf?hig, wie es für den t?glichen Gebrauch erforderlich ist. Zudem versch?rfen Erkrankungen der Gelenke, Muskeln, Sehnen, B?nder und Narbenzüge das Problem. Kontrakturen sind also ein Ph?nomen, gegen das angegangen werden muss, damit keine Bewegungseinschr?nkungen entstehen.     

Bemerkungen zu den Ertragsgesetzen

Ohne ZusammenfassungZu den nachstehenden Bemerkungen wurde ich durch ein Gespräch mit Prof. L. v. Mises angeregt, dem ich auch an dieser Stelle meinen besten Dank aussprechen Möchte.     

Kann der Zins ein Preis für „Warten“ sein?

Ohne Zusammenfassung     

Confronting the implications of the Cournot model with industry and firm data

This paper derives testable implications of the standard Cournot models and confronts these implications with real world data. Though we cannot expect that real world may be characterized by a simple static homogeneous model, it is surprising that little empirical work exists on testing the implications of this most popular model of oligopoly and non cooperative game theory.We make use of three data sets for manufacturing industry, two of them on the firm level, one about firms grouped according to their size. The relation of the results to the predictions of the Cournot model is discussed, as well as its relation to alternative oligopoly models. We specifically focus at the question whether the implications of the oligopoly models on the performance of large versus small firms are in line with the data.