Catálogo de publicaciones - libros

Localization investments are made mainly to increase the domestic content of manufacturing, thereby to reduce the costs and import dependency. Since localization investments include technology transfer, they positively affect the developing economies. The arrival of the new technology to the country has a positive impact on development of the equipment, workforce and the final product. It is often applied in automotive industry. Through localization investments not only improvement of OEMs, but also development of involved subsidiary industry can be induced. As a developing economy itself, Turkey encourages these kinds of investments and gives governmental incentives. The problem here is the valuation of these investment projects accurately by including all strategic impacts. Just because localization projects involve many future growth opportunities, conventional valuation tools cannot value those embedded opportunities correctly and the value of the project mostly appears negative or very low. This situation can cause a misjudgment at the incentives stage. This paper analyzes the localization project, first with conventional NPV analysis, then with real options analysis and finally compares the results. As for the options analysis, the results of potential involvement of various option types such as sequential options approach are used in the valuation of a case from Turkish automotive industry.

The widely deplored shortage of qualified personal in the nursing sector all over Europe can be traced to a number of reasons among which the relatively short duration that personal remains on the job ranks prominently. Besides the high psychic pressure involved with many nursing jobs, the degree of job satisfaction is also decreased by irregular working hours and inflexible working schedules.

The hospital field in Germany, with its 1.1 million employees and 62 billion Euro annual turnover (figures from 2001), represents a large and socially important field of activities [3, pp. 13]. If one considers the patients as “action object”, the work system (cf. [4, p. 81]) “hospital” is characterized by a number of particularities: First, treatment decision have to be made based on incomplete information and the treatment sequences must be carried out individually, meaning that they can only be planned to a limited degree. Furthermore, the complex treatment sequences must fulfil the treatment order reliably and efficiently. On the other hand, treatment processes must also take occupational health and safety and hygiene requirements of the medical and nursing personnel into account [10, p. 224].

The implementation of appropriate inventory control rules delivers the logistics operations of organizations a competitive advantage on the market place. This is also true for special types of networked manufacturing supply chains such as production networks which have complex topologies and increased complexity due to their logistic and production processes, information delays and the globalized markets. The paper builds the case of a production network and determines which inventory control policies applied in practice, order points and periodic-reviews, suit most the functions of the production network. Basically the production net consists of four manufacturing units that proceed to the joint development of products. In order to produce the four different items, the manufacturer orders from the other units as well as from the external supplier according to the exogenous customer demand. Although the case portrays a simplified instance of a production net, yet it already exhibits complex non linear dynamics inherent to such systems. The model is simulated with the system dynamics method which demonstrates the aptitude to describe distributed environments as long as product aggregation is permitted. The simulation results derived from the application of the inventory control rules on the production net will allow a detailed assessment of the suitability of each of the policies, in terms of the inventory costs criterion. A discussion on when to implement which inventory rule in respect to the functionalities of the production net will be pursued.

In this article we propose a new model for the simultaneous vehicle and crew scheduling problem occuring in the planning of urban mass transit systems. Our model incorporates the possibility of trip shifting in a given range in order to achieve a better solution.

Am 11. April 2007 werden in der Europäischen Union neue Vorschriften bezüglich der Lenk- und Ruhezeiten im Straßengütertransport in Kraft treten. Den neuen Vorschriften zufolge können Spediteure und Verlader für Verstöße der Fahrer haftbar gemacht werden. Da zudem Lenk- und Ruhezeiten einen signifikanten Einfluss auf Reisezeiten haben, ist eine Berücksichtigung der entsprechenden Regelungen bei der Tourenplanung unumgänglich. In diesem Beitrag wird gezeigt wie die neuen EU-Vorschriften in die Tourenplanung eingebracht werden können und das Vehicle Routing Problem mit Lenk- und Ruhezeiten (VRPLR) vorgestellt.

The share of logistics and transportation in the overall cost of a product is increasing. Subsequently, there is a growing pressure in the logistics industry for optimization and cost reduction. In this paper, we consider the issue of transport channel selection, a problem that has been overlooked for a long time. Typical choices for transport channels include round-trips from and to the depot, one-way tours (often called “milkruns”), delivery over a hub, or fixed-cost delivery services (e.g. a postal service). The overall optimization problem consists of two interdependent sub-problems: assigning shipments to transport channels, and optimizing the routes within each channel.

In this paper we address a rich variant of the vehicle routing problem which occurs in real-life applications. Among other aspects we take into consideration time windows, simultaneous delivery and pick-up at customer locations, multiple use of vehicles, and timely allocation of vehicles to loading bays at the depot. In order to solve practical instances of the resulting real-life rich vehicle routing problem, efficient methods are required. For this reason, we present a sampling procedure, which is a multi-start algorithm that executes in each call a substantial extension of the well-known savings algorithm. Using a set of suitable benchmark instances, we assess the performance of the proposed sampling procedure.

The decision of an airline about its service offering is a challenging task as it involves various decisions at the interface of operations and marketing: which origin-destination (OD) markets to serve, over which routes, and at which departure times (schedule design), at which price and other ticket conditions (pricing/fare product design), and what aircraft type to assign to each of these flights (fleet assignment). These decisions are highly interdependent with regard to their profit impact: on the one hand, the fleeted schedule fixes a large part of the cost; on the other hand, schedule, price and fare conditions are the most important factors influencing passenger’s choice and thus revenue. While schedule- and fare-related decisions are often treated in isolation in airline planning, profit maximizing service design should encompass the simultaneous determination of all features in the service package that drive profit. We develop a market-oriented model for airline network service design integrating flight schedule design, fleet assignment and pricing. Under suitable assumptions, the model is a mixed-binary problem with concave objective function and linear constrained that can be solved exactly by standard techniques. The optimal solution obtained at the strategic level can be used as input for operational revenue management models providing an interface for hierarchical decision making.

Even in its most basic form, the Vehicle Routing Problem and its variants are notoriously hard to solve. More often artificially intelligent algorithms are employed to provide near-optimal solutions. To be classified as “intelligent”, however, a solution strategy should be able to first analyze the environment in which the problem occurs, then solve it, and afterwards reflect on the solution process so as to improve future decision-making. Although reference is made to the entire context of the intelligence research project, this paper reports on the Tabu Search algorithm designed that catered for a problem with multiple soft time windows, a heterogeneous fleet, double scheduling, and time dependent travel time. An adaptive memory procedure was employed, initially populated with good initial feasible solutions, and the algorithm was tested on 60 problems based on established benchmark sets. The complex variant of the Vehicle Routing Problem required between 670 and 4762 seconds on a standard laptop computer, which is considered to be reasonable in the proposed application, and was consistent between different runs with an absolute mean deviation of 3.6%. The contribution is significant as it provides an algorithm that efficiently addresses a complex and practical application of the Vehicle Routing Problem. The algorithm can easily be extended to make use of multiple processors so as to reduce computational time.