Watering sportsgrounds during restrictions: perspectives from Melbourne Metropolitan Councils

Restrictions on outdoor water use have been a key element of the response to drought in metropolitan Melbourne. When stage 3A restrictions were introduced in April 2007, managers of grassed sportsgrounds mainly local councils were limited to watering 1 in 4 sites, and were required to make a 25% saving in water used outdoors. In late 2007, an allocation scheme was introduced as an alternative option available to councils for watering sportsgrounds. This research aims to inform the development of future drought response mechanisms, by providing insight into recent perspectives from Melbournes metropolitan local councils on watering sportsgrounds during drought. Through a series of semi-structured interviews, this research explored the underlying drivers, barriers, constraints and opportunities for efficient water management for grassed sportsgrounds

High-resolution lightfield photography using two masks

A major theme of computational photography is the acquisition of lightfield, which opens up new imaging capabilities, such as focusing after image capture. However, to capture the lightfield, one normally has to sacrifice significant spatial resolution as compared to normal imaging for a fixed sensor size. In this work, we present a new design for lightfield acquisition, which allows for the capture of a higher resolution lightfield by using two attenuation masks. They are positioned at the aperture stop and the optical path respectively, so that the four-dimensional (4D) lightfield spectrum is encoded and sampled by a two-dimensional (2D) camera sensor in a single snapshot. Then, during post-processing, by exploiting the coherence embedded in a lightfield, we can retrieve the desired 4D lightfield with a higher resolution using inverse imaging. The performance of our proposed method is demonstrated with simulations based on actual lightfield datasets. © 2012 Optical Society of America.published_or_final_versio

Standard cell layout with regular contact placement

The practicability and methodology of applying regularly placed contacts on layout design of standard cells are studied. The regular placement enables more effective use of resolution enhancement technologies, which in turn allows for a reduction of critical dimensions. Although placing contacts on a grid adds restrictions during cell layout, overall circuit area can be made smaller by a careful selection of the grid pitch, allowing slight contact offset, applying double exposure, and shrinking the minimum size and pitch. The contact level of 250 nm standard cells was shrunk by 10%, resulting in an area change ranging from -20% to +25% with an average decrease of 5% for the 84 cells studied. The areas of two circuits, a finite-impulse-response (FIR) filter and an add-compare-select (ACS) unit in the Viterbi decoder, decrease by 4% and 2%, respectively.published_or_final_versio

Depth resolution enhancement in optical scanning holography with a dual-wavelength laser source

In this paper, we use two point sources to analyze the depth resolution of an optical scanning holography (OSH) system with a single-wavelength source. A dual-wavelength source is then employed to improve it, where this dual-wavelength OSH (DW-OSH) system is modeled with a linear system of equations. Object sectioning in DW-OSH is obtained with the Fourier domain conjugate gradient method. Simulation results show that, with the two source wavelengths at 543 nm and 633 nm, a depth resolution at 2.5 mum can be achieved. Furthermore, an OSH system emulator is provided to demonstrate the performance of DW-OSH compared with a conventional OSH system.published_or_final_versio

Performance optimization for gridded-layout standard cells

The grid placement of contacts and gates enables more effective use of resolution enhancement techniques, which in turn allow a reduction of critical dimensions. Although the regular placement adds restrictions during cell layout, the overall circuit area can be made smaller and the extra manufacturing cost can be kept to the lowest by a careful selection of the grid pitch, using template-trim lithography method, allowing random contact placement in the vertical direction, and using rectangular rather than square contacts. The purpose of this work is to optimize the gridded-layout-based process. The trade-off between the layout area and manufacturing cost, and the determination of the minimum grid pitch are discussed in this paper. We demonstrate that it is a 1-D scaling instead of the conventional 2-D scaling for standard cells and the narrow MOSFETs inside after the application of the gridded layout on the contact and gate levels. The corresponding effects on circuit performances, including the leakage current, are also explored.published_or_final_versio

Standard cell design with resolution-enhancement-technique-driven regularly placed contacts and gates

The practicability and methodology of applying resolution-enhancement- technique-driven regularly placed contacts and gates on standard cell layout design are studied. The regular placement enables more effective use of resolution enhancement techniques (RETs), which in turn enables a reduction of critical dimensions. Although regular placement of contacts and gates adds restrictions during cell layout, the over-all circuit area can be made smaller and the number of extra masks and exposures can be kept to the lowest by careful selection of the grid pitch, using template-trim chromeless phase-shifting lithography approaches, enabling unrestricted contact placement in one direction, and using rectangular rather than square contacts. Four different fabrication-friendly layouts are compared. The average area change of 64 standard cells in a 130-nm library range from -4.2 to -15.8% with the four fabricationfriendly layout approaches. The area change of five test circuits using the four approaches range from -16.2 to +2.6%. Dynamic power consumption and intrinsic delay also improve with the decrease in circuits area, which is verified with the examination results. © 2005 Society of Pnoto-Optical Instrumentation Engineers.published_or_final_versio

Wind shear and wet and dry thermodynamic indices as predictors of thunderstorm motion and severity and application to the AVE 4 experimental data

Two types of parameters are computed and mapped for use in assessing their individual merits as predictors of occurrence and severity of thunderstorms. The first group is comprised of equivalent potential temperature, potential temperature, water vapor mixing ratio, and wind speed. Equivalent potential temperature maxima and strong gradients of equivalent potential temperature at the surface correlate well with regions of thunderstorm activity. The second type, comprised of the energy index, shear index, and energy shear index, incorporates some model dynamics of thunderstorms, including nonthermodynamic forcing. The energy shear index is found to improve prediction of tornadic and high-wind situations slightly better than other indices. It is concluded that further development and refinement of nonthermodynamic aspects of predictive indices are definitely warranted

Measuring Coverage of Prolog Programs Using Mutation Testing

Testing is an important aspect in professional software development, both to avoid and identify bugs as well as to increase maintainability. However, increasing the number of tests beyond a reasonable amount hinders development progress. To decide on the completeness of a test suite, many approaches to assert test coverage have been suggested. Yet, frameworks for logic programs remain scarce. In this paper, we introduce a framework for Prolog programs measuring test coverage using mutations. We elaborate the main ideas of mutation testing and transfer them to logic programs. To do so, we discuss the usefulness of different mutations in the context of Prolog and empirically evaluate them in a new mutation testing framework on different examples.Comment: 16 pages, Accepted for presentation in WFLP 201

Applying an evolutionary approach for learning path optimization in the next-generation e-learning systems

Learning analytics is targeted to better understand and optimize the process of learning and its environments through the measurement, collection and analysis of learners' data and contexts. To advise people's learning in a specific subject, most intelligent e-learning systems would require course instructors to explicitly input some prior knowledge about the subject such as all the pre-requisite requirements between course modules. Yet human experts may sometimes have conflicting views leading to less desirable learning outcomes. In a previous study, we proposed a complete system framework of learning analytics to perform an explicit semantic analysis on the course materials, followed by a heuristic-based concept clustering algorithm to group relevant concepts before finding their relationship measures, and lastly employing a simple yet efficient evolutionary approach to return the optimal learning sequence. In this paper, we carefully consider to enhance the original evolutionary optimizer with the hill-climbing heuristic, and also critically evaluate the impacts of various experts' recommended learning sequences possibly with conflicting views to optimize the learning paths for the next-generation e-learning systems. More importantly, the integration of heuristics can make our proposed framework more self-adaptive to less structured knowledge domains with conflicting views. To demonstrate the feasibility of our prototype, we implemented a prototype of the proposed e-learning system framework for learning analytics. Our empirical evaluation clearly revealed many possible advantages of our proposal with interesting directions for future investigation. © 2013 IEEE.published_or_final_versio