Improved mixed-integer programming models for the multiprocessor scheduling problem with communication delays

We revise existing and introduce new mixed-integer programming models for the Multiprocessor scheduling problem with communication delays. The basis for both is the identification of two major modeling strategies one of which can be considered ordering-based, and the other assignment-based. We first reveal redundancies in the encoding of feasible solutions found in present formulations and discuss how they can be avoided. For the assignment-based approach, we propose new inequalities that lead to provably stronger continuous relaxations and better performance in practice. Moreover, we derive a third, novel modeling strategy and show how to more compactly linearize assignment formulations with quadratic constraints. In a comprehensive experimental comparison of representative models that reflect the state-of-the-art in terms of strength and size, we evaluate not only running times but also the obtained lower and upper bounds on the makespan for the harder instances of a large scale benchmark set.     

Form Perception of Partly Occluded Shapes in 4‐Month‐Old Infants

Two habituation experiments were conducted to investigate how 4‐month‐old infants perceive partly occluded shapes. In the first experiment, we presented a simple, partly occluded shape to the infants until habituation was reached. Then we showed either a probable completion (one that would be predicted on the basis of both local and global cues) or an improbable completion. Longer looking times were found for the improbably completed shape (compared to probable and control conditions), suggesting that the probable shape was perceived during partial occlusion. In the second experiment, infants were habituated to more ambiguous partly occluded shapes, where local and global cues would result in different completions. For adults, the percept of these shapes is usually dominated by global influences. However, after habituation the infants looked longer at the globally completed shapes. These results suggest that by the age of 4 months, infants are able to infer the perceptual completion of partly occluded shapes, but for more ambiguous shapes, this completion seems to be dominated by local influences.     

Single-peaked Compatible Preference Profiles: Some Combinatorial Results

This paper examines combinatorial problems in connection with single-peaked preference orderings on a unidimensional scale. A binary relation, dominance, is defined on the set of connected orderings. Relevant properties of the corresponding poset and cover graph are discussed. A formula for the number of pairs of connected orderings consistent with spatial single-peakedness is derived. The total number of such pairs is shown to be expressible in a simple form involving binomial probabilities. A possible application is a coalition formation process of the kind examined by Brams et al. (J Theor Polit 14:359–383, 2002), where actors have single-peaked preferences on a common scale.     

Service user involvement in social work education: experiences from Germany and implications for a European perspective

ABSTRACT

Service user involvement (SUI) in social work education has gained widespread attention in Europe and other continents. Nevertheless, experiences on including service users in social work education have not been reported from Germany or other German-speaking countries to date. This paper reports preliminary experiences with implementing SUI in a bachelor’s programme of social work in a German University of Applied Sciences. The main goals of the current paper are (1) to provide a background for implementing service user approaches in Germany by introducing the structure of social work education in Germany; (2) to report experiences from a weekend seminar where service users worked together with students of social work in the framework of a curriculum of a German University of Applied Sciences and (3) to formulate some implications of these experiences for SUI across Europe. The main results were that introducing service user involvement into a German curriculum of social work is possible but needs careful reflection and planning. Experiences gathered in the weekend seminar with service users were encouraging for service users, students and teachers. We conclude that systematically implementing SUI into German curricula of social work is important.     

The reliance on recognition and majority vote heuristics over privacy concerns when selecting smartphone apps among German and US consumers

The smartphone app market is a prime example of a digital market where consumers are tasked with selecting one option among a plethora of alternatives, at times indistinguishable from one another. Building upon findings on information processing and decision-making, we postulate that consumers follow simple (rather than complex) heuristic rules to navigate the app market. In particular, we focus on two such strategies: the recognition heuristic and the majority vote heuristic. App privacy information was also considered as a potentially salient cue in the decision-making process, given the personal data stored on smartphones. Results of a mixed-method design (behavioral analysis and think-aloud protocols) study with German (N?=?18) and US (N?=?25) students find a dominance of the recognition heuristic. Decisions are further supported by majority vote heuristics. Privacy information is largely disregarded, particularly by US participants. Implications for app market design and engagement are discussed.     

Both Whistleblowers and the Scientists They Accuse Are Vulnerable and Deserve Protection

Whistleblowers play an important role diagnosing research misconduct, but often experience severe negative consequences. That is also true for incorrectly accused scientists. Both categories are vulnerable and deserve protection. Whistleblowers must proceed carefully and cautiously. Anonymous whistleblowing should be discouraged but cannot be ignored when the allegations are specific, serious, and plausible. When accused of a breach of research integrity it is important to be as transparent as possible. Sometimes accusations are false in the sense that the accuser knows or should know that the allegations are untrue. A mala fide whistleblower typically does not act carefully and we postulate a typology that may help in detecting them. Striking the right balance between whistleblower protection and timely unmasking false and identifying incorrect accusations is a tough dilemma leaders of research institutions have to face.