Electrification of a city bus network—An optimization model for cost-effective placing of charging infrastructure and battery sizing of fast-charging electric bus systems

The deployment of battery-powered electric bus systems within the public transportation sector plays an important role in increasing energy efficiency and abating emissions. Rising attention is given to bus systems using fast charging technology. This concept requires a comprehensive infrastructure to equip bus routes with charging stations. The combination of charging infrastructure and bus batteries needs a reliable energy supply to maintain a stable bus operation even under demanding conditions. An efficient layout of the charging infrastructure and an appropriate dimensioning of battery capacity are crucial to minimize the total cost of ownership and to enable an energetically feasible bus operation. In this work, the central issue of jointly optimizing the charging infrastructure and battery capacity is described by a capacitated set covering problem. A mixed-integer linear optimization model is developed to determine the minimum number and location of required charging stations for a bus network as well as the adequate battery capacity for each bus line. The bus energy consumption for each route segment is determined based on individual route, bus type, traffic, and other information. Different scenarios are examined in order to assess the influence of charging power, climate, and changing operating conditions. The findings reveal significant differences in terms of required infrastructure. Moreover, the results highlight a trade-off between battery capacity and charging infrastructure under different operational and infrastructure conditions. This paper addresses upcoming challenges for transport authorities during the electrification process of the bus fleets and sharpens the focus on infrastructural issues related to the fast charging concept.     

Staged venture capital contracting with ratchets and liquidation rights

This paper uses real options analysis to study later round financing in the presence of two standard venture capital contracting provisions: anti-dilution (ratchet) and liquidation preference. We argue that such provisions can preclude financing of a positive NPV venture in the case of a large follow-on financing relative to firm value. Liquidation preference contracting at multiples greater than one is not feasible in the later round if the financing is small relative to firm value. We highlight an interaction effect between the two provisions: increasing the liquidation multiple can help to avoid dilution and the need for the prior venture capitalist to waive ratchet provisions.     

What you are is what you like—similarity biases in venture capitalists' evaluations of start-up teams

This paper extends recent research studying biases in venture capitalist's decision making. We contribute to this literature by analyzing biases arising from similarities between a venture capitalist and members of a venture team. We summarize the psychological foundations of such similarity effects and derive a set of hypotheses regarding the impact of similarity on the assessment of team quality. Using data from a conjoint experiment with 51 respondents, we find that venture capitalists tend to favor teams that are similar to themselves in type of training and professional experience. Our results have important implications for academics and practitioners alike.     

Why do rich countries prefer free trade over free migration? The role of the modern welfare state

"According to traditional trade theory (Heckscher-Ohlin), free trade and free migration are equivalent measures of economic integration leading both to an equalization of factor prices. This prediction is in sharp opposition to the observed preference of rich countries for free trade over free migration. We provide an explanation for this inconsistency: the redistribution policies in the countries. Social welfare in countries with a relatively small number of low-skilled native workers is higher with free trade than with free migration due to redistribution of income towards immigrating workers."     

Estimation of the change point of a distribution based on the number of failed test items

This paper discusses the family of life distributions with failure rate functions which decrease initially until a change point and remain constant thereafter. The paper focuses on the estimation for the change point of the failure rate function. While point estimation of the change point of the failure rate function has been discussed by some authors, one can hardly find any existing work on the interval estimation of the change point. In this paper, a method for constructing approximate confidence intervals for the change point is proposed. The proposed approximate confidence intervals are based on the number of failed test items at or before a fixed inspection time. Received: September 1999     

Frank Romeike und Matthias Müller-Reichart: Risikomanagement in Versicherungsunternehmen. Grundlagen, Methoden, Checklisten und Implementierung

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