Using genetic programming and decision trees for generating structural descriptions of four bar mechanisms

Four bar mechanisms are basic components of many important mechanical devices. The kinematic synthesis of four bar mechanisms is a difficult design problem. A novel method that combines the genetic programming and decision tree learning methods is presented. We give a structural description for the class of mechanisms that produce desired coupler curves. Constructive induction is used to find and characterize feasible regions of the design space. Decision trees constitute the learning engine, and the new features are created by genetic programming.

A quest for helpful feedback to programming coursework

The 2011 National Student Survey (NSS) revealed that 40% of full-time students in England do not think that the feedback on their work has been helpful, even though 66% of these students agreed that the feedback was detailed and 62% of them agreed that the feedback has been prompt. Detailed feedback that is not considered helpful by students means a waste of tutors' time while students continue to struggle with their learning. What do students consider as helpful feedback? What are the qualities of helpful feedback? What are the preferred forms of feedback? How should tutors write feedback so that students will find it helpful? Can ICT help to improve the quality of feedback? In our ongoing search for answers to the above questions, we have trialled the use of a novel online application (eCAF) to assess programming coursework from engineering, mathematics and computing students and, through a survey, have collected their views on the feedback received. The survey reveals that most students prefer electronic feedback as given through eCAF, with verbal feedback ranked second and hand-written feedback ranked even lower. The survey also indicates that the feedback from some tutors is considered more helpful than others. We report on the detailed findings of the survey. By comparing the kinds of feedback given by each tutor who took part in the trial, we explore ways to improve the helpfulness of feedback on programming coursework in a bid to promote learning amongst engineering students.

Procedural justice in procurement management and inclusive interorganizational relations:An institutional perspective

This paper applies the concept of procedural justice to one of the most important focal points of interorganizational relations: the purchaser-supplier relationship. The few extant studies of the concept in the purchaser-supplier domain have overlooked an important aspect of this key relationship: that is, inclusiveness in procurement. This is despite the fact that interest in the specific empirical context of supply chain links between large purchasing organizations (LPOs) and ethnic minority suppliers (EMSs) from disadvantaged communities proceeds apace on both sides of the Atlantic. Institutional theory is used to examine the form that procedural justice takes in eight case studies of LPOs from the private and public sectors, which actively engage with inclusive procurement management initiatives in England. The guiding question is twofold: 'What may LPO approaches to installing procedural justice in procurement management entail?' and 'How are these approaches shaped?' This paper identifies specific approaches to installing procedural justice for inclusive procurement and submits theoretical propositions about how these are shaped. The study contributes to a macro-level assessment of procedural justice, i.e. interorganizational procedural justice, as a significant aspect of inclusive interorganizational relationships, which is a domain in need of theoretical development.

Optimal design of the renewable energy map of Greece using weighted goal-programming and data envelopment analysis

Renewable energy forms have been widely used in the past decades highlighting a "green" shift in energy production. An actual reason behind this turn to renewable energy production is EU directives which set the Union's targets for energy production from renewable sources, greenhouse gas emissions and increase in energy efficiency. All member countries are obligated to apply harmonized legislation and practices and restructure their energy production networks in order to meet EU targets. Towards the fulfillment of 20-20-20 EU targets, in Greece a specific strategy which promotes the construction of large scale Renewable Energy Source plants is promoted. In this paper, we present an optimal design of the Greek renewable energy production network applying a 0-1 Weighted Goal Programming model, considering social, environmental and economic criteria. In the absence of a panel of experts Data Envelopment Analysis (DEA) approach is used in order to filter the best out of the possible network structures, seeking for the maximum technical efficiency. Super-Efficiency DEA model is also used in order to reduce the solutions and find the best out of all the possible. The results showed that in order to achieve maximum efficiency, the social and environmental criteria must be weighted more than the economic ones.

How do practitioners understand? Practitioner perceptions of an object-oriented programming.

In the computer science community, there is considerable debate about the appropriate sequence for introducing object-oriented concepts to novice programmers. Research into novice programming has struggled to identify the critical aspects that would provide a consistently successful approach to teaching introductory object-oriented programming. Starting from the premise that the conceptions of a task determine the type of output from the task, assisting novice programmers to become aware of what the required output should be, may lay a foundation for improving learning. This study adopted a phenomenographic approach. Thirty one practitioners were interviewed about the ways in which they experience object-oriented programming and categories of description and critical aspects were identified. These critical aspects were then used to examine the spaces of learning provided in twenty introductory textbooks. The study uncovered critical aspects that related to the way that practitioners expressed their understanding of an object-oriented program and the influences on their approach to designing programs. The study of the textbooks revealed a large variability in the cover of these critical aspects.

Leader-member exchange, group- and individual-level procedural justice and reactions to performance appraisals

Previous research has established that relationships with authority figures and procedural justice perceptions are important in terms of the way in which employees react to organizational procedures that affect them. What is less clear are the reasons why exchange quality with authorities is related to perceptions of process fairness and the role of procedural justice climate in this process. Results indicate that individual-level perceptions of procedural justice, but not performance ratings, partially mediate the relationship between exchange quality and reactions to performance appraisals, and that procedural justice climate is positively related to perceptions of procedural justice and appraisal reactions. These results support a more relational than instrumental view of justice perceptions in organizational procedures bound by exchange quality with an authority figure. Our study suggests that it is essential for managers to actively monitor and manage employee perceptions of process fairness at the group and individual levels. © 2015 Wiley Periodicals, Inc.