On minimax-regret Huff location models

We address the following single-facility location problem: a firm is entering into a market by locating one facility in a region of the plane. The demand captured from each user by the facility will be proportional to the users buying power and inversely proportional to a function of the user-facility distance. Uncertainty exists on the buying power (weight) of the users. This is modeled by assuming that a set of scenarios exists, each scenario corresponding to a weight realization. The objective is to locate the facility following the Savage criterion, i.e., the minimax-regret location is sought. The problem is formulated as a global optimization problem with objective written as difference of two convex monotonic functions. The numerical results obtained show that a branch and bound using this new method for obtaining bounds clearly outperforms benchmark procedures.Ministerio de Educación y CienciaJunta de Andalucí

An assessment of learning gains from educational animated videos versus traditional extension presentations among farmers in Benin*

Article purchasedThis study compared the efficacy of linguistically and dialectically localized animated educational videos (LAV) against traditional learning extension (TLE) presentations for learning gains of knowledge around agricultural- and healthcare-related topics within a rural population in Benin. While both approaches demonstrated learning gains, LAV resulted in significantly higher test scores and more detailed knowledge retention. A key contribution of this research, moreover, involves the use of mobile phone technologies to further disseminate educational information. That is, a majority of participants expressed both a preference for the LAV teaching approach and a heightened interest in digitally sharing the information from the educational animations with others. Because the animations are, by design, readily accessible to mobile phones via Africa’s explosively expanding digital infrastructure, this heightened interest in sharing the animated videos also transforms each study participant into a potential a learning node and point of dissemination for the educational video’s material as well

A Positive Project Outcome: Lessons from a Non-Dominant Government University-Based Program

This article explores factors contributing to a non-dominant collaboration paradigm in a partnership between a government-based international development agency and a university-based non-governmental organization. Anchored in Wood’s and Gray’s collaborative framework, this article describes how the steeply hierarchical partnership navigated the elements of collaboration – organizational autonomy; shared problem domain; interactive processes; shared rules, norms, and structures; and decision making – to produce non-dominant values and practices deriving from negotiated processes, rules, norms, and structures that produced positive collaboration outcomes. In particular, a history of prior mutually beneficial interactions emerges as a critical precondition for achieving a non-dominant collaboration in this case study’s steeply hierarchical organizational relationship, one in which egalitarianism and equal decision-making regarding the agenda and the goals of the collaboration could have been highly constrained

Scientific animations without borders

Julia Bello-Bravo and Barry Robert Pittendrigh outline an emerging strategy to connect local and global experts to create and deploy educational content for low-literate learners in the form of animated videos

Using Information Technologies (ICTs) to Improve Theobroma Cocoa Extension Service: Lessons from the Case of Ghanaian Bean Farmers

Ghana’s modern cocoa production depends on farmers having access to innovations and updated best practices delivered through “new” information and communication technology (ICT) channels. However, extension services continue to face familiar delivery shortfalls affecting both the national-level extent of Ghana’s cocoa production and the local livelihoods of its producers. This chapter draws on questionnaire data collected during a training workshop for postharvest loss prevention with mostly university-educated farmers to explore how they access innovation and best practices information through new and old technological channels. Key findings indicate that while farmers utilize both old and new ICTs, they still experience the familiar barriers of low agricultural extension agent-to-farmer ratios and shortages of resources. Recommendations include (1) ensuring that the affordances of “old” technologies are amplified rather than replaced by “new” ones, and (2) the use of highly scalable educational animations deployed individually for training or through virtual communities of practices to “bypass” the perennial issue of resource shortfalls in extension services

Removal of entrained organic matter in the copper electrolyte by ozonation

Organic matter-in-aqueous entrainment is a serious problem in the hydrometallurgical extraction of copper from ore. Current inefficiencies, changes in the morphology and orientation of cathode deposit are some of the problems when organic matter is present in the advance electrolyte. In addition, negative effects upon metabolic activity of bioleaching microorganisms are reported due to entrained organic matter in the raffinate electrolyte. In view of these problems, the objective of this study was to evaluate ozonation as an alternative method for the removal of entrained organic matter present in an advanced electrolyte. For this purpose, ozonation during 30 min of synthetic solutions using a bubble glass column reactor at different ozone concentrations, flow rates and temperatures were studied. It was found that the increase in all of these operating parameters is not necessarily associated with an increase of the removal efficiency, and their effects on the mass transfer rate, chemical reaction rate, ozone solubility and contact time play a decisive role in the ozonation process. Thus, the best operating conditions were found at 6.7 wt.%, 1 L min-1 and 27 °C and reached a removal efficiency of 94.5%. This result demonstrated that removal of entrained organic matter in strongly acid solution by ozonation could be an alternative technology

Scientific Animations Without Borders and Njala University

Scientific Animations Without Borders (SAWBO) is a University of Illinois at Urbana-Champaign (Illinois) based program that was launched in 2011. Created and co-managed by Julia Bello-Bravo and Barry Pittendrigh, SAWBO is part of the College of Liberal Arts and Sciences and the Center for African Studies on the Illinois campus. It promotes agricultural, health, and women’s empowerment knowledge for people of all literacy levels and linguistic backgrounds throughout the world. This Brief describes the work of SAWBO and provides a specific case study for their work with Njala University in Sierra LeoneOpe

Attitude control research with educational nanosatellites

This paper introduces the three-axis attitude control of the ESAT platform. ESAT is a modular nanosatellite that implements the popular 10x10x10 cm CubeSat standard, designed for hands-on learning at different educational levels as well as professional training. ESAT features the full set of characteristic spacecraft subsystems (power, on-board data handling, attitude control, communications, and payload). The satellite can be disassembled to focus on each subsystem, one at a time, or used all together, and features a flexible ground segment. Courses using the ESAT platform are imparted in our university, as part of the last year of the master’s degree in Aerospace engineering, and in other institutions like the ESA Academy. They cover aspects ranging from subsystems design to testing and spacecraft operations. In addition, the platform is used in master’s thesis and research activities. Although the version that is currently being used in the courses allows only one-axis attitude control, the ESAT is in continuous development and two prototypes of the satellite have already been developed that allow three-axis control based on reaction wheels and/or magnetorquers, which is essential for the testing and verification of attitude determination and control algorithms. For this purpose, the ground support equipment has also been updated to be able to carry out the turns in three axes, with the development of new testbeds and a complete magnetic field simulator. The present work aims to show the new three-axis platform designs and its main functionalitie

Global Solutions for International Development Partnerships: Beyond Insider/Outsider Binaries

In recent years, information and communication technologies for development (ICT4D) approaches have facilitated international development work, but still more effective ICT4D deployments are needed. This article examines how one ICT4D initiative, Scientific Animations without Borders (SAWBO), works with partners in Africa not only to transcend problematic insider / outsider binaries that impact solution delivery but also to implement inter-organizational collaborations on research and mission-critical knowledge-transfer goals that effectively reach the widest diversity of target populations