Teaching Tip: Evaluating Visualizations with a Compact Rubric

Students now have readily available and powerful tools to access, manipulate, combine, and visualize data. Acquiring data and visual literacy requires more than knowledge of how to use these tools. Students need to engage with assignments that challenge them to make relatively complex visualizations, interpret them, and explain why these interpretations matter for given problem situations. This paper describes how to structure feedback for these assignments. The few published visualization evaluation rubrics are mainly oriented toward how-to-do-it heuristics. This paper makes a contribution by presenting, defining, and giving examples of the use of an innovative compact rubric for evaluating visualizations (CRVE). This rubric eliminates some of the length and complexity of heuristic evaluation, focusing on interpretation and relevance. In a graduate business intelligence course, students showed definite improvement over the course of the semester in the construction of visualizations, telling a story with headlines, and striving for data exploration. However, higher levels of technical correctness of visualizations did not necessarily correspond to better interpretations. This finding underscores the importance of emphasizing interpretation through a feedback mechanism like the CRVE presented here

Too good to waste: Creating biochar from cleared vegetation as a soil improver and carbon sink

Road construction has a considerable carbon footprint and is likely to be impacted significantly by international and national responses to climate change. Although avoidance of carbon emissions during the design and construction phases is preferred, it is inevitable that some carbon emissions will result in large projects, due to the carbon intensive nature of road construction. Typical offset projects have focused around the biosequestration of carbon, including large-scale tree planting. Whilst tree planting projects achieve broader benefits from reafforestation, concerns surrounding the biodiversity value of largely monoculture, agro-forestry projects are adding to traditional criticisms such as the measurability and permanency. Concerns over tree planting as an approach to offsetting have paved the way for consideration of other biological methods for carbon sequestration that are better able to respond to tests of measurability and permanency and attempt to preserve the biodiversity value of cleared land. Biochar, charcoalised woody biomass, is a soil improver, which is being investigated globally due to its potential to store carbon in the soil for extremely long time periods. On-site production of biochar using cleared vegetation is an approach to carbon offsetting that allows for both the sequestration of carbon in the soil and enhances revegetation activities in the road reserve. Low technology approaches are practical, using existing road construction equipment to dig pits in which the vegetation is slowly carbonised through low oxygen combustion. High technology but portable approaches for on-site generation using modern biomass to energy conversion technologies (pyrolysis and gasification) are also possible and able to produce biochar and renewable fuels, which can be used in a number of conventional generation technologies such as internal combustion engines and turbines. Roadside vegetation used in modern biomass pyrolysis technologies has the potential to produce around 30 kg of carbon sequestration for each gigajoule of renewable fuel produced. Biochar may sequester up to 50 per cent of the carbon in the original vegetation, having the potential to become an important part of future revegetation activities in road construction This paper will discuss several approaches to onsite biochar production from road vegetation, in particular a recent trial from Western Australia and the opportunities for reducing carbon emissions and the sequestration of carbon that would otherwise be burnt or left to rapidly decay as chipped or mulched material

CROSS-CULTURAL INFORMATION TECHNOLOGY RESEARCH: THE CASE OF EASTERN EUROPE AND THE USSR

This paper discusses the specific problems and issues involved in studying information technologies in Eastern Europe and the USSR in the more general context of cross-cultural information technology (IT) research. The results reported are based on eight years of research into international information technologies by the Mosaic Group at the University of Arizona. The problems of doing this kind of work, where field and empirical studies are often impractical, are examined. Four analytical techniques, supported by a computer-based research environment, are advanced as means to solve these problems

Co-production of high-protein feed and bio-oil for poultry protein productivity and fuel switching in Mozambique: Avoiding transesterification and food insecurity

This chapter explores the next steps of expanding village poultry productivity in Mozambique post control of communicable diseases by assessing co-production of edible oils and high protein poultry feeds. The production of oil was analysed from the perspective of a suitable non-fossil fuel without the need for transesterification to produce biodiesel. A range of feedstock issues were considered for co-producing vegetable oil as a fuel and high protein animal feed. Technical considerations of the direct use of straight vegetable oil (SVO) in diesel engines and oil conversion to biodiesel are discussed, and we identify more suitable options for additional mechanisation options for smallholder farmers. Potential synergies with private-public partnerships between smallholders, food production companies, and education institutions to assist introduction of new mechanisation options were investigated. The research findings indicate the lack of access to training and equipment, and also education and experience of refining bio-oil derivatives, and the parallel high demand for human and animal food/feed presented a high prospectivity of producing SVO for use in suitable engines. The chapter concludes with a strategy to maximise the potential benefits of SVO production and use within agricultural communities

Development of an optimal biogas system design model for Sub-Saharan Africa with case studies from Kenya and Cameroon

The optimal biogas system design model (OBSDM) described in this paper is intended to be used as a decision-making tool to increase awareness of the potential of biogas technology for different applications in Sub-Saharan Africa (SSA). The decision-making tool identifies the most suitable biodigester design based on user defined inputs, including energy and fertiliser requirements; feedstock (type, amount, and rate of supply); water supply; land use (area, soil type, ground water level); climate (temperature and rainfall); construction materials available locally; and the priorities (based on sustainability criteria) of the intended biogas user. The output of the model provides a recommended design with estimates of the expected costs, energy and fertiliser production, and links to contact biodigester suppliers. In order to test the model, data from household surveys conducted in rural regions of Kenya and Cameroon were used as inputs to the model. An innovative fixed dome biodigester design, which uses stabilised soil blocks instead of bricks, was identified as optimal for both Kenyan and Cameroonian rural households. The expected performance of the optimal biogas system design from the model output was consistent with survey data on existing biogas systems in the region

A PV-battery-powered 12V gas membrane with wood desiccants for postharvest hermetic grain storage

Around half of agricultural production in sub-Saharan Africa is 'lost' or 'wasted' due to lack of an available market, poor handling at postharvest (methods and technology), and through poor road access. Effective postharvest processing is critical to ensure small producers best access local markets in nearby villages. This chapter explores small portable (renewable energy-powered, oil-less) compressors and high-pressure gas membrane technology as technical zero-emission alternatives to selectively purge seed and grain storage systems. The gas membrane uses inert and non-toxic gasses (including nitrogen) which are effective in preventing production loss to pests (fungus, insects, and others) by use of physical and environmental barriers only (i.e., no chemical fumigants) to reduce conducive conditions (especially moisture). Furthermore, the use of simple dry wood desiccants may be also a cost-effective solution for moisture management in sealed seed and grain storage. This chapter demonstrates that while proprietary gas membrane technology is expensive for sub-Saharan African smallholders, commercial arrangements (including generic drug provision at cost) may create a viable tool and foster food security by improved storage for various production conditions under variable climate

Hole Doping Effects on Spin-gapped Na2Cu2TeO6 via Topochemical Na Deficiency

We report the magnetic susceptibility and NMR studies of a spin-gapped layered compound Na2Cu2TeO6 (the spin gap $\Delta\sim$ 250 K), the hole doping effect on the Cu2TeO6 plane via a topochemical Na deficiency by soft chemical treatment, and the static spin vacancy effect by nonmagnetic impurity Zn substitution for Cu. A finite Knight shift at the $^{125}$Te site was observed for pure Na2Cu2TeO6. The negative hyperfine coupling constant $^{125}A_{tr}$ is an evidence for the existence of a superexchange pathway of the Cu-O-Te-O-Cu bond. It turned out that both the Na deficiency and Zn impurities induce a Curie-type magnetism in the uniform spin susceptibility in an external magnetic field of 1 T, but only the Zn impurities enhance the low-temperature $^{23}$Na nuclear spin-lattice relaxation rate whereas the Na deficiency suppresses it. A spin glass behavior was observed for the Na-deficient samples but not for the Zn-substituted samples. The dynamics of the unpaired moments of the doped holes are different from that of the spin vacancy in the spin-gapped Cu2TeO6 planes.Comment: 4 pages, 7 figures, to be published in J. Phys. Soc. Jpn. Vol. 75, No. 8 (2006

Absence of Edge Localized Moments in the Doped Spin-Peierls System CuGe1−x_{1-x}Six_{x}O3_3

We report the observation of nuclear quadrupole resonance (NQR) of Cu from the sites near the doping center in the spin-Peierls system CuGe$_{1-x}$Si$_{x}$O$_3$. The signal appears as the satellites in the Cu NQR spectrum, and has a suppressed nuclear spin-lattice relaxation rate indicative of a singlet correlation rather than an enhanced magnetic correlation near the doping center. Signal loss of Cu nuclei with no neighboring Si is also observed. We conclude from these observations that the doping-induced moments are not in the vicinity of the doping center but rather away from it.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

Bostonia: 1998-1999, no. 1, 3-4

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs