PORTFOLIO OPTIMIZATION WITH JUMPS AND UNOBSERVABLE INTENSITY PROCESS

We consider a financial market with one bond and one stock. The dynamics of the stock price process allow jumps which occur according to a Markov-modulated Poisson process. We assume that there is an investor who is only able to observe the stock price process and not the driving Markov chain. The investor's aim is to maximize the expected utility of terminal wealth. Using a classical result from filter theory it is possible to reduce this problem with partial observation to one with complete observation. With the help of a generalized Hamilton–Jacobi–Bellman equation where we replace the derivative by Clarke's generalized gradient, we identify an optimal portfolio strategy. Finally, we discuss some special cases of this model and prove several properties of the optimal portfolio strategy. In particular, we derive bounds and discuss the influence of uncertainty on the optimal portfolio strategy.     

Joint Production and the Structure of Technology: A Generalization

In this paper, we have a peek inside the black box of technology in an attempt to get a better understanding of the concept of joint production. We introduce the notion of input and output subtechnologies; these are then used as building blocks to define various types of production processes, either joint or nonjoint. Thus, in the 2×2 case, we are able to identify up to 36 different production structures, some of which are well known, but most of which are new. These are all described in the primal quantity space as well as in the dual price space. Comparative statics results for the 2×2 joint production process are derived.     

Techno-ökonomische Bewertung von Energie-Autarkie für die Energieversorgung von Einfamilienhäusern

Many consumers currently follow the idea of energy self-sufficiency and try to contribute to meet their energy needs in order to become independent and self-sufficient from the central power supply system. In order to achieve load-oriented energy self-sufficiency the provision of energy must cover the full energy demand at any time. Against this background, in this paper the costs and potentials of a load-oriented energy self-sufficiency of single-family homes are analysed. Thereby it is differentiated between electricity-, heat- and energy self-sufficiency. The modelling is carried out with the simulation environment ?Polysun Designer“ which allows a high temporal dynamic simulation of the annual energy demand and supply.The results show that, within the investigated supply variations, the highest levels of energy self-sufficiency can be achieved by an energy supply system completely based on electricity using a combination of PV; heat pump and battery storage. Depending on the building standard, a maximum of 45 (existing buildings) and 71?% (new buildings) of the building’s energy demand can be covered with renewable energy. The economic evaluation however has shown that under present conditions, none of the investigated supply variants can compete with conventional energy supply (public grid connection + gas condensing boiler).     

More than Just an Opinion: The Effect of Verbal Self‐Expression on Consumer Choice

In an ever‐widening range of occasions, consumers have the opportunity to comment and express their opinions on brands and products. However, little is known about how voicing opinions about the choice options before actually choosing might affect consumer choice, and specifically liking of choice. This paper proposes that pre‐choice opinion expression undermines the effect of post‐choice bolstering, because opinion sufficiently satisfies self‐expressive needs and therefore supersedes the use of subsequent choice as a self‐expressive resource. This proposition is based on the assumption that opinion can psychologically substitute for choice, because the two represent alternative routes to self‐expression. Two experiments provide empirical support for this hypothesis. Study 1 showed that after articulating their opinions about the choice options, participants were less likely to idealize their choices, and this effect was mediated by a change in the construal of choice as self‐expression. Study 2 further showed that this effect is moderated by public versus private occasions of opinion voicing and by individual differences in the value of expression. Together, findings support that opinion is enough to express the self, and if such an opportunity is made available prior to choosing, consumers’ liking of their choices is weakened.     

GDP growth,terms-of-trade effects,and total factor productivity

The purpose of this paper is to assess the contribution of each one of the major factors explaining Australian nominal GDP growth: technological change, movements in the terms of trade, increases in the endowments of labour and capital, and changes in domestic output prices. We use an index number technique as well as an econometric approach. Moreover, we look at several methods to decompose total factor productivity growth into secular and unexpected components. All our empirical results have a tight theoretical foundation, being based on the GDP function approach to modelling the production sector of an open economy.