Refine
Year of publication
- 2016 (61) (remove)
Document Type
- Article (30)
- Doctoral Thesis (19)
- Monograph/Edited Volume (10)
- Postprint (1)
- Review (1)
Is part of the Bibliography
- yes (61)
Keywords
- Cloud computing (2)
- Nonprofit-Organisationen (2)
- Qualitätsmanagement (2)
- microfinance (2)
- quality management (2)
- öffentlicher Sektor (2)
- "rich country-poor country debate" (1)
- Abduktion (1)
- Adam Smith (1)
- Advance production (1)
Institute
- Wirtschaftswissenschaften (61) (remove)
Situated at the intersection of the literatures on speculative storage and non-renewable commodity scarcity, this paper considers whether changes in persistence have occurred in long-run U.S. prices of the energy commodities crude oil, natural gas and bituminous coal. We allow for a structural break when testing for a break in persistence to avoid a change in the stochastic properties of prices being confounded by an unaccounted-for deterministic shift in the price series. We find that coal prices are trend stationary throughout their evolution and that oil prices change from stationarity to non-stationarity in the decade between the late 1960s to late 1970s. The result on gas prices is ambiguous. Our results demonstrate the importance of accounting for a possible structural shift when testing for breaks in persistence, while being robust to the exact date of the structural break. Based on our analysis we caution against viewing long-run energy commodity prices as being non-stationary and conclude in favor of modeling commodity market fundamentals as stationary, meaning that speculative storage will tend to have a dampening effect on prices. We also cannot reject that long-run prices of coal and, with some hesitation, gas follow a Hotelling-type rule. In contrast, we reject the Hotelling rule for oil prices since the late 1960s/early 1970s. (C) 2016 Elsevier B.V. All rights reserved.
In some countries including Germany unemployed workers can increase their income by working a few hours per week. The intention is to keep unemployed job seekers attached to the labour market and to increase their job-finding probabilities. To analyze the unemployment dynamics of job seekers with and without marginal employment, we consider an inflow sample into unemployment and estimate multivariate duration models. While we do not find any significant impact on the job finding probability in a model with homogeneous effects, models allowing for time-varying coefficients indicate a decreased job finding probability of marginal employment at the beginning of the unemployment spell and an increased job finding probability for the long-term unemployed. Our results suggest that job seekers with marginal employment find more stable post-unemployment jobs, and we find some evidence that the relationship between marginal employment and wages and employment stability varies with respect to skill levels, sector and labor market tightness. (C) 2016 Elsevier B.V. All rights reserved.
This article addresses security and privacy issues associated with storing data in public cloud services. It presents an architecture based on a novel secure cloud gateway that allows client systems to store sensitive data in a semi-trusted multi-cloud environment while providing confidentiality, integrity, and availability of data. This proxy system implements a space-efficient, computationally-secure threshold secret sharing scheme to store shares of a secret in several distinct cloud datastores. Moreover, the system integrates a comprehensive set of security measures and cryptographic protocols to mitigate threats induced by cloud computing. Performance in practice and code quality of the implementation are analyzed in extensive experiments and measurements. (C) 2016 Elsevier B.V. All rights reserved.
This article studies the effect of child care provision on family structure. We present a model of a marriage market with positive assortative matching, where in equilibrium, the poorest women stay single. Couples have to decide on the number of children and spousal specialization in home production of public goods and child care. We then study how child care provision affects the equilibrium. Due to specialization in home production, the incentive to use child care is smaller for married mothers than for single mothers. We show that this increases the number of single mothers and the divorce rate. Using survey data from Germany, we present suggestive empirical evidence consistent with this finding. (JEL codes: J12 and J13).
Many organizations use business process models for documenting their business operations. In recent years, the Business Process Model and Notation (BPMN) evolved into the leading standard for process modeling. However, BPMN is complex: The specification offers a huge variety of different elements and often several representational choices for the same semantics. This raises the question of how well modelers can deal with these choices. Empirical insights into BPMN usage from the perspective of practitioners are still missing. We close this gap by analyzing a large set of BPMN 2.0 process models from practice. We found that particularly representational choices for splits and joins, the correct use of message flow, the proper decomposition of models, and the consistent labeling appear to be connected with quality issues. Based on our findings we give five recommendations how these issues can be avoided in the future. The work summarized in this extended abstract has been published in [LMG16].
Many organizations use business process models to document business operations and formalize business requirements in software-engineering projects. The Business Process Model and Notation (BPMN), a specification by the Object Management Group, has evolved into the leading standard for process modeling. One challenge is BPMN's complexity: it offers a huge variety of elements and often several representational choices for the same semantics. This raises the question of how well modelers can deal with these choices. Empirical insights into BPMN use from the practitioners' perspective are still missing. To close this gap, researchers analyzed 585 BPMN 2.0 process models from six companies. They found that split and join representations, message flow, the lack of proper model decomposition, and labeling related to quality issues. They give five specific recommendations on how to avoid these issues.