eri, J. S. M., Petersen, K. ., & Mendes, E. . (2020). An empirically evaluated checklist for surveys in software engineering. Information and Software Technology, 119, 106240.
Siebert, J. U., Brandenburg, M. ., & Siebert, J. . (2020). Defining and Aligning Supply Chain Objectives Before, During, and After the COVID-19 Pandemic. IEEE Engineering Management Review, 48, 72–85. http://doi.org/10.1109/EMR.2020.3032369
Zander, S. ., Montag, M. ., Wetzel, S. ., & Bertel, S. . (2020). A gender issue? - How touch-based interactions with dynamic spatial objects support performance and motivation of secondary school students. Computers & Education, 143, 103677. http://doi.org/https://doi.org/10.1016/j.compedu.2019.103677
Abstract
Mobile devices are seen to incorporate characteristics which can support learning and problem solving in general and specific abilities, such as spatial ones (e.g. mental rotation). Central relevant characteristics of these devices are the availability of multiple representations (e.g. dynamic and static) and the direct interaction via touch, pointing and tracing with displayed information. The primary aim of the present study was to investigate the effectiveness of direct interactive, dynamic interactions with spatial tasks on mobile devices as compared to purely static, non-interactive versions of the same tasks. We expected that dynamic, interactive tasks support mental processes while solving spatial tasks would be especially helpful for learners with difficulties in mental rotation and low expectancies regarding their spatial abilities. Therefore, the second focus of the study was to examine whether the expected beneficial effects of dynamic interactions were equally beneficial for both genders. This was motivated by previous studies that revealed gender differences in performance and motivational beliefs regarding spatial tasks to the disadvantage of females. We used a mixed within-between subject design with presentation format (static vs. dynamic) and gender (female vs. male) as factors and success rate, mental effort, intrinsic motivation, and frustration as dependent variables. The study was conducted in four classes (7th grade, N = 46) in two secondary schools. To test gender related pre-assumptions, spatial abilities and motivation were assessed before solving the actual rotation tasks. A MANOVA with single-comparison follow-up tests revealed increased success rates and decreased mental effort for both genders in the dynamic condition, whereas beneficial effects for intrinsic motivation and frustration were restricted to female students. Process data for rotation behavior was registered for dynamic tasks: an analysis hinted at more exploratory ways of solving spatial tasks for females and at more goal-oriented approaches for male students.
Chirvi, M. ., Kiesewetter, D. ., Maiterth, R. ., Menzel, M. ., & Tschinkl, D. . (2020). Zuordnung von Sonderausgaben in der Rentenphase als Bestimmungsfaktor für das Vorliegen einer Doppelbesteuerung beim Übergang zur nachgelagerten Besteuerung gesetzlicher Renten. Steuer Und Wirtschaft, 97(3). http://doi.org/https://doi.org/10.9785/stuw-2020-970307
Abstract
Die seit langem kontrovers diskutierte Frage, ob es beim Übergang zur nachgelagerten Rentenbesteuerung zu einer unzulässige Doppelbesteuerung kommt, lässt sich klar beantworten. Wenn die Sonderausgaben, die in der Rentenphase aus den Beiträgen zur gesetzlichen Kranken- und Pflegeversicherung resultieren, als ein die Renten steuerfreistellendes Element des Steuersystems eingestuft werden, existiert kein Doppelbesteuerungsproblem. Vielmehr ist eine deutlich Minderbesteuerung und damit eine Steuervergünstigung für Rentner zu konstatieren. Gänzlich anders verhält es sich, wenn derartige Sonderausgaben nicht als Teil der steuerfreien Rente angesehen werden. Dann unterliegt die Mehrzahl der Rentner einer ungerechtfertigten Doppelbesteuerung. In beiden Fällen lässt sich eine pauschalierte und zudem passgenauere Besteuerung gesetzlicher Renten erreichen, indem § 22 EStG entsprechend modifiziert wird.
Rebs, T. ., Thiel, D. ., Brandenburg, M. ., & Seuring, S. . (2019). Impacts of stakeholder influences and dynamic capabilities on the sustainability performance of supply chains: a system dynamics model. Journal of Business Economics, 89, 893–926. http://doi.org/10.1007/s11573-019-00940- (Original work published 2024)
Abstract
Dynamic capabilities (DCs) are crucial for companies to attain competitive advantage in dynamic business environments and supply chains, where environmental and social aspects are considered by sustainable supply chain management (SSCM). However, the effects of stakeholder influences on SSCM performance, which results from the interplay of DCs and SSCM practices, need to be analyzed. Therefore, a system dynamics (SD) model is proposed to include the influences of governmental, shareholder, and other external stakeholder pressure. The system behavior, i.e., the company’s SSCM performance, can thus be analyzed in face of varying time delays of stakeholder influences. Findings indicate that different intensities of stakeholder influences affect the development of SSCM practices and DCs of a focal company, and thus, overall SSCM performance. Consequently, intensities of stakeholder influences should be managed accordingly, while the impact of time delays has to be understood to control SSCM performance. The insights gained from the model support the decision- and policy-making, which can be considered from the perspective of the focal company, the regulatory authorities, the shareholders, and other external stakeholders that ultimately translate into customer pressure.
Fleming, P. A., Peiffer, A. ., & Schlipf, D. . (2019). Wind turbine controller to mitigate structural loads on a floating wind turbine platform. Journal of Offshore Mechanics and Arctic Engineering, 141. http://doi.org/10.1115/1.4042938 (Original work published 2024)
Boysen, C. ., Kaldemeyer, C. ., Hilpert, S. ., & Tuschy, I. . (2019). Integration of Flow Temperatures in Unit Commitment Models of Future District Heating Systems. Energies, 12, 1061. http://doi.org/10.3390/en12061061 (Original work published 2024)
Würth, I. ., Valldecabres, L. ., Simon, E. ., Möhrlen, C. ., Uzunoğlu, B. ., Gilbert, C. ., … Kaifel, A. . (2019). Minute-scale forecasting of wind power results from the collaborative workshop of IEA wind task 32 and 36. Energies, 12, 712. http://doi.org/10.3390/en12040712 (Original work published 2024)
Uzunkol, O. . (2019). Comments on “verifiable outsourced attribute-based signature scheme”. Multimedia Tools and Applications , 78(9), 11735–11742. http://doi.org/10.1007/s11042-018-6725-7
Abstract
Ren and Jiang recently published a “verifiable outsourced attribute-based signature scheme” in Multimedia Tools and Applications. In this note, we first provide two attacks on the verifiability of the semi-signatures of this scheme by showing that a malicious signing-cloud service provider (S-CSP) can always cheat the signer unlike the authors’ claim. Moreover, one of these attacks also implies that an untrusted S-CSP can always forge signatures contrary to the claimed unforgeability against chosen message attacks. Therefore, this scheme unfortunately does not satisfy the main security properties for a delegated signature scheme.
Moritz, S. ., & Uzunkol, O. . (2019). Secure delegation of group exponentiations: Efficient and fully verifiable schemes with two servers. Security and Privacy, n/a, e70. http://doi.org/https://doi.org/10.1002/spy2.70 (Original work published 2019)
Abstract
Abstract Recent interactions between cloud service providers and mobile resource-constrained devices have increased the interest on the delegation of expensive computations to powerful external server providers. At the same time, security and verifiability of the delegated computation are challenging though highly demanded requirements for various application scenarios. Many security solutions using advanced cryptographic technologies require a large number of highly expensive group exponentiations (GEs). In this paper, we address the problems regarding secure and verifiable delegation of GEs. We first analyze two delegation schemes for GEs both introduced recently in Cluster Computing by Fu et al with the claim that they both provide full verifiability. Particularly, we show that the first scheme is only verifiable with a probability at most 2/3, and the second scheme is totally unverifiable. Then, we propose a secure, efficient and fully verifiable delegation scheme InvDel for a GE using two servers, where one of which is malicious. With InvDel the delegator does not require computations of any group inversions (GIs) while providing full verifiability. Then, we extend InvDel to SimInvDel which is the first, efficient and secure delegation scheme for n-simultaneous GEs achieving full verifiability for n > 1. Secondly, we give implementation results of InvDel and SimInvDel using an Android application together with a comprehensive efficiency analysis of computation and communication with the previous schemes. For instance, when the required CPU costs for a single GE are compared with a 4092-bit modulus, InvDel is more than 220-times (resp. more than two times) more efficient than the local computation (resp. using a previous fully verifiable scheme proposed in the literature). Finally, we also utilize InvDel and SimInvDel to speed-up the verification of Schnorr s signature and Cramer-Shoup encryption schemes.