User,Use & Utility Research

Business and Information Systems Engineering (BISE) is at a turning point. Planning, designing, developing and operating IT used to be a management task of a few elites in public ad-ministrations and corporations. But the continuous digitization of nearly all areas of life changes the IT landscape fundamentally. Success in this new era requires putting the human perspective – the digital user – at the very heart of the new digitized service-led economy. BISE faces not just a temporary trend but a complex socio-technical phenomenon with far-reaching implications. The challenges are manifold and have major consequences for all stakeholders, both in information systems and management research as well as in practice. Corporate processes have to be re-designed from the ground up, starting with the user’s perspective, thus putting usage experience and utility of the individual center stage. The digital service economy leads to highly personalized application systems while organizational functions are being fragmented. Entirely new ways of interacting with information systems, in particular beyond desktop IT, are being invented and established. These fundamental challenges require novel approaches with regards to innovation and development methods as well as adequate concepts for enterprise or service system architectures. Gigantic amounts of data are being generated at an accelerating rate by an increasing number of devices – data that need to be managed. In order to tackle these extraordinary challenges we introduce ‘user, use & utility’ as a new field of BISE that focuses primarily on the digital user, his or her usage behavior and the utility associated with system usage in the digitized service-led economy. The research objectives encompass the development of theories, methods and tools for systematic requirement elicitation, systems design, and business development for successful Business and Information Systems Engineering in a digitized economy – information systems that digital users enjoy using. This challenge calls for leveraging insights from various scientific disciplines such as Design, Engineering, Computer Science, Psychology and Sociology. BISE can provide an integrated perspective, thereby assuming a pivotal role within the digitized service led economy.     

Profitability of momentum strategies in international markets: The role of business cycle variables and behavioural biases

The paper investigates whether business cycle variables and behavioural biases can explain the profitability of momentum trading in three major European markets. Unlike previous studies, the paper nests both risk-based and behavioural-based variables in a two-stage model specification in an attempt to explain momentum profits. The findings show that, although momentum profitability in European markets is unexplained by conditional asset pricing models, it is attributable to asset mispricing that systematically varies with global business conditions. In addition, behavioural variables do not appear to matter much. Thus risk factors, which are undetected thus far and are largely attributable to the business cycle, could explain the momentum payoffs in European stock markets.     

Abschätzung der Varianz stetiger Merkmale aus Intervallbreite und Mittelwert

Ohne Zusammenfassung     

Comparison of Hypothesis Testing and Bayesian Model Selection

The main goal of both Bayesian model selection and classical hypotheses testing is to make inferences with respect to the state of affairs in a population of interest. The main differences between both approaches are the explicit use of prior information by Bayesians, and the explicit use of null distributions by the classicists. Formalization of prior information in prior distributions is often difficult. In this paper two practical approaches (encompassing priors and training data) to specify prior distributions will be presented. The computation of null distributions is relatively easy. However, as will be illustrated, a straightforward interpretation of the resulting p-values is not always easy. Bayesian model selection can be used to compute posterior probabilities for each of a number of competing models. This provides an alternative for the currently prevalent testing of hypotheses using p-values. Both approaches will be compared and illustrated using case studies. Each case study fits in the framework of the normal linear model, that is, analysis of variance and multiple regression.     

Building from Scratch: New Cities,Privatized Urbanism and the Spatial Restructuring of Johannesburg after Apartheid

By the start of the twenty‐first century, the once dominant historical downtown core of Johannesburg had lost its privileged status as the center of business and commercial activities, the metropolitan landscape having been restructured into an assemblage of sprawling, rival edge cities. Real estate developers have recently unveiled ambitious plans to build two completely new cities from scratch: Waterfall City and Lanseria Airport City (formerly called Cradle City) are master‐planned, holistically designed ‘satellite cities’ built on vacant land. While incorporating features found in earlier city‐building efforts, these two new self‐contained, privately‐managed cities operate outside the administrative reach of public authority and thus exemplify the global trend toward privatized urbanism. Waterfall City, located on land that has been owned by the same extended family for nearly 100 years, is spearheaded by a single corporate entity. Lanseria Airport City/Cradle City is a planned ‘aerotropolis’ surrounding the existing Lanseria airport at the northwest corner of the Johannesburg metropole. These two new private cities differ from earlier large‐scale urban projects because everything from basic infrastructure (including utilities, sewerage, and the installation and maintenance of roadways), landscaping, security services, the regulation of common spaces, and selling and branding the city are firmly in the hands of private profit‐making corporate entities and outside the mandate of public authorities.     

Multikriterielles Entscheidungsmodell für Anpassungsmaßnahmen am Beispiel der L/H-Gas-Umstellung in Deutschland

The German gas supply system is separated into two networks: one for high-calorific gas (H-gas) and one for low-calorific gas (L-gas). In particular, the L-gas volume is declining significantly, which means that there will be problems in security of supply in near future. This paper highlights the most important aspects that have to be considered when adjusting the German gas network to the future decline of L-gas production. First, the article discusses different possible adjustment options: (1) adjustment of market areas from low-calorific gas supply to high-calorific gas supply, (2) blending facilities (conversion of high calorific gas using nitrogen or air) and (3) the combination of both options. Subsequently, the authors outline the necessary planning process that must precede any adjustment option. The so-called network differentiation is followed by the network modeling: Using the net present value method and taking into account certain constraints, the authors define a simple optimization problem to determine the most economical investment and adjustment times for each option. Based on first model considerations it can be concluded that the implementation of adjustment options should be delayed as long as possible without compromising the security of supply. Nevertheless, an early start of the planning process is mandatory to ensure that adjustment options can be established in due time before an L-gas supply deficit occurs. The question, which adjustment option should be chosen, cannot be answered universally. It depends on the conditions and structure of the network as well as the structure of the final consumers.     

Raising offtake from cattle grazed on natural rangelands in sub-Saharan Africa: a transaction cost economics approach

Farmers in sub‐Saharan Africa are constrained by large transaction costs associated with marketing of their livestock. However, transaction costs are often not taken into account in the analysis of factors hampering the development of livestock marketing in this region. This article empirically measures the influence of transaction costs on the offtake from cattle grazed on natural rangelands in Uganda. The study is based on the monitoring of 696 cattle transactions in three districts of Uganda from August 2004 to August 2005. The estimated models suggest that proportional transaction costs represented by the state of roads, distance to markets, and time taken to reach the market are important variables constraining market participation. In order to raise offtake from the national herd, it is essential to explicitly address these costs. One potential solution is collective action in marketing of livestock in which proportional and fixed transaction costs are reduced and shared among the group members.