An EVACS simulation with nested transactions

Documented here is the recent effort of the MISSION Kernel Team on an Extra-Vehicular Activity Control System (EVACS) simulation with nested transactions. The team has implemented the EVACS simulation along with a design for nested transactions. The EVACS simulation is a project wide aid to exploring Mission and Safety Critical (MASC) applications and their support software. For this effort it served as a trial scenario for demonstrating nested transactions and exercising the transaction support design. The EVACS simulation is a simulation of some aspects of the Extra-Vehicular Activity Control System, in particular, just the selection of communication frequencies. Its current definition is quite narrow, serving only as a starting point for prototyping purposes. (EVACS itself may be supplanted in a larger scenario of a lunar outpost with astronauts and a lunar rover.) Initially the simulation of frequency selection was written without consideration of nested transactions. This scenario was then modified to embed its processing in nested transactions. To simplify the prototyping effort, only two aspects of the general design for transaction support have been implemented: the basic architecture and state recovery. The simulation has been implemented in the programming language Smalltalk. It consists of three components: (1) a simulation support code which provides the framework for initiating, interacting and tracing the system; (2) the EVACS application code itself, including its calls upon nested transaction support; and (3) a transaction support code which implements the logic necessary for nested transactions. Each of these components deserves further description, but for now only the transaction support is discussed

Land Trust Response to Renewable Energy Siting Challenges in New York

Energy policies promoting energy independence, grid modernization, climate change mitigation, and clean energy standards are a leading driver of land-use change in the United States. This has resulted in an increased pressure to develop land. The recent focus by states to expand renewable energy poses an interesting challenge to organizations dedicated to conserving open space and natural resources, creating a potential tension between competing “green” goals. In response, The Land Trust Alliance, a national organization supporting over 1,100 member land trusts, has recently set a goal to “empower land trusts to encourage the buildout of renewable energy facilities while steering the facilities away from sensitive lands through a pilot project in New York.” This report creates a baseline assessment of New York’s land trusts that evaluates the extent to which land trusts are aware of and responding to the changing policies around renewable energy and its impacts on land use. Using an online survey, 42 land trusts were sampled. The data was analyzed using simple aggregations and Spearman’s Rank-Order Correlation tests. Survey results found that just under half of land trusts surveyed are beginning to form policies around renewable energy on conserved land yet only 7% are incorporating renewable energy into their strategic plans. This report suggests five areas in which the Alliance can provide support to New York’s land trusts to improve their preparedness around renewable energy siting. These include: mission alignment, information flows, strategic planning, siting utility scale wind and solar, and easements and fee-lands. These focal areas present New York’s land trusts with an opportunity to boost relevancy and/or visibility through engaging more deeply in a set of broader policy goals for New York State around climate and energy

MalStone: Towards A Benchmark for Analytics on Large Data Clouds

Developing data mining algorithms that are suitable for cloud computing platforms is currently an active area of research, as is developing cloud computing platforms appropriate for data mining. Currently, the most common benchmark for cloud computing is the Terasort (and related) benchmarks. Although the Terasort Benchmark is quite useful, it was not designed for data mining per se. In this paper, we introduce a benchmark called MalStone that is specifically designed to measure the performance of cloud computing middleware that supports the type of data intensive computing common when building data mining models. We also introduce MalGen, which is a utility for generating data on clouds that can be used with MalStone

Kinetics of thermal barrier oxide interactions with molten silicates

The degradation of thermal barrier coatings (TBCs) by molten silicates (CMAS) represents a significant barrier to increased operation temperatures of gas turbine engines and thus fuel efficiency. A promising mechanism for CMAS mitigation has been found in certain TBC chemistries (e.g. Gd2Zr2O7) that undergo reactive crystallization – the crystallization of new, thermodynamically favored phases, which contain both melt and TBC constituents (e.g. apatite). Significant work has been undertaken to understand the thermodynamics of TBC-CMAS systems and the possible reaction phases, but little quantitative data on the kinetics of these interactions exists today; this includes: the (i) rate of TBC dissolution into the melt, (ii) diffusion of TBC constituents within the melt, and (iii) reaction product crystallization rates. Please click Additional Files below to see the full abstract

Tool to design the primary electrical insulation system of low voltage rotating machines fed by inverters

International audienceIn this communication, we describe a methodologic tool (software) that give instruction to design the coil winding of low voltage machines fed by inverters. The aim of this tool is to bring useful information to the coil manufacturer who has, first, to respect the size of the slots, the total copper section (slot occupancy) and the coil voltage that are imposed by the motor designer. Then, to increase the PDIV between turns and between turns and ground to the highest value. For that purpose, by using a numerical simulation that takes into account the Paschen's law, the developed software will provide how to choose and arrange the enameled wires in the slots: random or form-wound coils, wires shape (round or rectangular), number of wires in parallel by turn, insulation thickness (grade), turns arrangement,... up to find the best solution that allow to respect both motor designer and PDIV constraints. Some practical examples will be given to prove the efficiency of such a tool

Incentive complexity, bounded rationality and effort provision

Using field and laboratory experiments, we demonstrate that the complexity of incentive schemes and worker bounded rationality can affect effort provision, by shrouding attributes of the incentives. In our setting, complexity leads workers to over-provide effort relative to a fully rational benchmark, and improves efficiency. We identify con tract features, and facets of worker cognitive ability, that matter for shrouding. We find that even relatively small degrees of shrouding can cause large shifts in behavior. Our results illustrate important implications of complexity for designing and regulating workplace incentive contracts

On radiative transfer in water spray curtains using the discrete ordinates method

International audienc