A Redesigned Benders Decomposition Approach for Large-Scale In-Transit Freight Consolidation Operations

The growth in online shopping and third party logistics has caused a revival of interest in finding optimal solutions to the large scale in-transit freight consolidation problem. Given the shipment date, size, origin, destination, and due dates of multiple shipments distributed over space and time, the problem requires determining when to consolidate some of these shipments into one shipment at an intermediate consolidation point so as to minimize shipping costs while satisfying the due date constraints. In this paper, we develop a mixed-integer programming formulation for a multi-period freight consolidation problem that involves multiple products, suppliers, and potential consolidation points. Benders decomposition is then used to replace a large number of integer freight-consolidation variables by a small number of continuous variables that reduces the size of the problem without impacting optimality. Our results show that Benders decomposition provides a significant scale-up in the performance of the solver. We demonstrate our approach using a large-scale case with more than 27.5 million variables and 9.2 million constraints

Two Notions of Privacy Online

Users of social networking websites tend to disclose much personal information online yet seem to retain some form of an expectation of privacy. Is this expectation of privacy always unreasonable? How do users of online social networks define their expectations of privacy online? These questions were the impetus behind an empirical study, the findings of which are presented in this Article. The project, simultaneously conducted in Canada, at Ryerson University, and in the United States, at the University of Miami, consisted of a survey regarding personal information protection and expectations of privacy on online social networks (OSNs). Approximately 2,500 young adults between the ages of 18 and 24 were surveyed about the personal information they post online, the measures they take to protect such information, and their concerns, if any, regarding their personal information. Respondents also reacted to several hypothetical scenarios in which their privacy was breached on an OSN by measures both within and beyond their control. The theoretical assumption underlying this research project is that two prevalent and competing notions of privacy online exist: one rooted in control and the other in dignity. Of the two, the idea of privacy as control over one\u27s personal information has, to date, been predominant. Legislation, regulation, corporate policy, and technology are often analyzed and evaluated in terms of the measure of control offered to individuals over their personal information. Leading OSNs, such as Facebook and MySpace, propagate a notion of privacy as user control. However, online social networking poses a fundamental challenge to the theory of privacy as control. A high degree of control cannot preclude the possibility that online socializers would post unflattering, defamatory, or personal information about each other, and that this information would in turn be available to a large, if not unrestricted, online audience. Many online socializers post personal information seemingly without much concern over the loss of control, yet it seems that online socializers react with indignation when their personal information is accessed, used, or disclosed by individuals perceived to be outside their social network. The findings presented here indicate indeed that online socializers have developed a new and arguably legitimate notion of privacy online, that if accepted by OSNs, will offer online socializers both control and protection of their dignity and reputation. We call this notion network privacy. According to network privacy, information is considered by online socializers to be private as long as it is not disclosed outside of the network to which they initially disclosed it, if it originates with them, or as long as it does not affect their established online personae, if it originates with others. OSNs, as businesses profiting from socializing online, are best positioned to offer online socializers, often the young and vulnerable, effective protection in accordance with their notion of network privacy above and beyond regular measures of personal information control, and they should be required to do so

Validation of the organizational justice scale in a portuguese context

This article presents a Portuguese translation and cultural modification of the Organizational Justice Scale of Niehoff and Moorman (1993). The scale was tested in two correlational studies, one with 115 employees from the technical staff of a Portuguese organization and a second with 59 Portuguese teachers, testing the scale’s discriminant validity through comparison with other measures such as psychological contract violation, organizational identification, work motivation, job satisfaction and perceived ability–job fit. The scale showed satisfying consistency and in a factorial analysis of the Portuguese version; the item distribution per factor was the same as that of the original scale (Niehoff & Moorman, 1993). The Portuguese Organizational Justice scale showed adequate reliability and validity. Therefore, this Portuguese version can be considered a suitable instrument to assess organizational justice among the Portuguese population.info:eu-repo/semantics/acceptedVersio

Homological computation using spanning trees

We introduce here a new F2 homology computation algorithm based on a generalization of the spanning tree technique on a finite 3-dimensional cell complex K embedded in ℝ3. We demonstrate that the complexity of this algorithm is linear in the number of cells. In fact, this process computes an algebraic map φ over K, called homology gradient vector field (HGVF), from which it is possible to infer in a straightforward manner homological information like Euler characteristic, relative homology groups, representative cycles for homology generators, topological skeletons, Reeb graphs, cohomology algebra, higher (co)homology operations, etc. This process can be generalized to others coefficients, including the integers, and to higher dimension

Homological tree-based strategies for image analysis

Homological characteristics of digital objects can be obtained in a straightforward manner computing an algebraic map φ over a finite cell complex K (with coefficients in the finite field F2={0,1}) which represents the digital object [9]. Computable homological information includes the Euler characteristic, homology generators and representative cycles, higher (co)homology operations, etc. This algebraic map φ is described in combinatorial terms using a mixed three-level forest. Different strategies changing only two parameters of this algorithm for computing φ are presented. Each one of those strategies gives rise to different maps, although all of them provides the same homological information for K. For example, tree-based structures useful in image analysis like topological skeletons and pyramids can be obtained as subgraphs of this forest

EU External Relations: Exclusive Competence Revisited

This Article will focus on the question of exclusive competence in the field of EU external relations, especially in the light of recent developments. After a brief discussion on the origins and development of exclusive competence, a distinction will be made between common commercial policy, which has traditionally been the most important area of an explicit “a priori” exclusive competence, and what is often called an implicit exclusive competence, which, as it is today based on some general criteria enshrined in TFEU Article 3(2), may be called “supervening” exclusive competence. With regard to both categories, the main focus will be on recent developments, notably the impact of the Treaty of Lisbon, which introduced the TFEU and its Articles 2 and 3, as well as the case law of the European Court of Justice (“ECJ” or the “Court”) following the entry into force of the Treaty of Lisbon, on December 1, 2009

Social dominance modulates eavesdropping in zebrafish

Group living animals may eavesdrop on signalling interactions between conspecifics and integrate it with their own past social experience in order to optimize the use of relevant information from others. However, little is known about this interplay between public (eavesdropped) and private social information. To investigate it, we first manipulated the dominance status of bystander zebrafish. Next, we either allowed or prevented bystanders from observing a fight. Finally, we assessed their behaviour towards the winners and losers of the interaction, using a custom-made video-tracking system and directional analysis. We found that only dominant bystanders who had seen the fight revealed a significant increase in directional focus (a measure of attention) towards the losers of the fights. Furthermore, our results indicate that information about the fighters' acquired status was collected from the signalling interaction itself and not from post-interaction status cues, which implies the existence of individual recognition in zebrafish. Thus, we show for the first time that zebrafish, a highly social model organism, eavesdrop on conspecific agonistic interactions and that this process is modulated by the eavesdroppers' dominance status. We suggest that this type of integration of public and private information may be ubiquitous in social learning processes.FCT PhD fellowship: (SFRH/BD/33280/2007), Champalimaud Neuroscience Programme

Systematic analysis of direct-drive baseline designs for shock ignition with the Laser MégaJoule

We present direct-drive target design studies for the laser mégajoule using two distinct initial aspect ratios (A = 34 and A = 5). Laser pulse shapes are optimized by a random walk method and drive power variations are used to cover a wide variety of implosion velocities between 260 km/s and 365 km/s. For selected implosion velocities and for each initial aspect ratio, scaled-target families are built in order to find self-ignition threshold. High-gain shock ignition is also investigated in the context of Laser MégaJoule for marginally igniting targets below their own self-ignition threshold

Direct-Drive Shock-Ignition for the Laser Megajoule.

We present a review of direct-drive shock ignition studies done as alternative for the Laser Mega-Joule to achieve high thermonuclear gain. One-dimensional analysis of HiPER-like Shock-ignited target designs is presented. It is shown that high gain can be achieved with shock ignition for designs which do not ignite only from the laser compression. Shock ignition is achieved for different targets of the fast ignition family which are driven by an absorbed energy between 100 kJ and 850kJ and deliver thermonuclear energies between 10-130 MJ. Shock-Ignition of Direct-Drive Double-Shell non-cryogenic target is also addressed. 2D results concerning the LMJ irradiation geometry are presented. Few systematic analyses are performed for the fuel assembly irradiation uniformity using the whole LMJ configuration or a part of the facility, and for the ignitor spike uniformity. Solutions for fuel assembly and shock ignition on LMJ using 2D calculations are presented. It is shown that high-gain shock-ignition is possible with intensity of each quad less than 1e15 W/cm2but low modes asymmetries displace the ignitor power in the spike towards higher powers