770 research outputs found

    A Nonlinear Dynamic Interactive Decision Analysis and Support System (DIDASS/N)

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    The Interactive Decision Analysis group at IIASA has developed a decision analysis and support system, called "DIDASS". Based on the Reference Point Approach for multicriteria analysis, it is an attempt to combine the analytical power of the "hard" computer model with the qualitative assessments of the decision maker. In general, DIDASS is capable of dealing with both linear and nonlinear problems. Theoretical and practical tests for solving nonlinear problems of regional water policies in open-pit mining areas have elucidated the need for an especially designed nonlinear DIDASS version. Following the presentation of the extended nonlinear version, DIDASS/N is described. DIDASS/N has been developed in collaboration between the Interactive Decision Analysis Group and the Regional Water Policies Project at IIASA. DIDASS/N has been written in FORTRAN 77. The use of operating-system-dependent statements or commands has been avoided

    We pay you for your land and stay amongst you folks : settler colonialism and indigenous power in Southwest Washington Territory

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    Against a teleological narrative of inevitable U.S. hegemony in what is now the southwest corner of Washington State, this work argues that settler colonialism has been a co-creation of local indigenous peoples and settlers that has emerged from the mid-nineteenth century onward through continuous negotiations of power and influence. The uneasy co-existence between metanarratives of U.S. westward expansion and local narratives produced through the colonial encounter give rise to productive contradictions that provide materials to reframe the dominant narratives that continue to naturalize settler colonial power today

    Plagiarism Deterrence in CS1 Through Keystroke Data

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    Recent work in computing education has explored the idea of analyzing and grading using the process of writing a computer program rather than just the final submitted code. We build on this idea by investigating the effect on plagiarism when the process of coding, in the form of keystroke logs, is submitted for grading in addition to the final code. We report results from two terms of a university CS1 course in which students submitted keystroke logs. We find that when students are required to submit a log of keystrokes together with their written code they are less likely to plagiarize. In this paper we explore issues of implementation, adoption, deterrence, anxiety, and privacy. Our keystroke logging software is available in the form of an IDE plugin in a public plugin repository

    A Practical Model of Student Engagement While Programming

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    We consider the question of how to predict whether a student is on or off task while working on a computer programming assignment using elapsed time since the last keystroke as the single independent variable. In this paper we report results of an empirical study in which we intermittently prompted CS1 students working on a programming assignment to self-report whether they were engaged in the assignment at that moment. Our regression model derived from the results of the study shows power-law decay in the engagement rate of students with increasing time of keyboard inactivity ranging from a nearly 80% engagement rate after 45 seconds to 30% after 32 minutes of inactivity. We find that students remain engaged in programming for a median of about 8 minutes before going off task, and when they do go off task, they most often return after 1 to 4 minutes of disengagement. Our model has application in estimating the amount of engaged time students take to complete programming assignments, identifying students in need of intervention, and understanding the effects of different engagement behaviors

    Accurate Estimation of Time-on-Task While Programming

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    In a recent study, students were periodically prompted to self-report engagement while working on computer programming assignments in a CS1 course. A regression model predicting time-on-task was proposed. While it was a significant improvement over ad-hoc estimation techniques, the study nevertheless suffered from lack of error analysis, lack of comparison with existing methods, subtle complications in prompting students, and small sample size. In this paper we report results from a study with an increased number of student participants and modified prompting scheme intended to better capture natural student behavior. Furthermore, we perform a cross-validation analysis on our refined regression model and present the resulting error bounds. We compare with threshold approaches and find that, in at least one context, a simple 5-minute threshold of inactivity is a reasonable estimate for whether a student is on-task or not. We show that our approach to modeling student engagement while programming is robust and suitable for identification of students in need of intervention, understanding engagement behavior, and estimating time taken on programming assignments

    Health Savings Account - Eligible High Deductible Health Plans: Updating the Definition of Prevention

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    High-deductible health plans (HDHPs) are an important and growing part of the health insurance landscape. By some estimates, as many as 80 percent of large employers may offer an HDHP in 2014. In 2013, more than 15 million Americans received health coverage through an HDHP, a more than a threefold increase since 2007.As outlined by the U.S. Treasury Department, individuals with an HSA-eligible HDHP are required to pay the full cost of most medications and services -- in theory utilizing pre-tax HSA funds -- until deductibles are met. However, the 2003 authorizing legislation and further guidance include a safe harbor allowing plans to cover primary preventive services, those typically deemed to prevent the onset of disease, before the deductible is satisfied.Services or benefits meant to treat "an existing illness, injury or condition," are excluded from first-dollar coverage in HSA-eligible HDHPs, which encompasses most secondary preventive services. For example, plans are prohibited from providing first dollar coverage of disease management services such as insulin, eye and foot exams, and glucose monitoring supplies for patients with diabetes.As chronic disease conditions currently make up 75 percent of total U.S. health spending, appropriate chronic disease management is an important tool to lower long-term health care costs. As the market for HDHPs grow, it is important that they maintain the flexibility to allow for effective health management of all beneficiaries. This report addresses the strict definition of prevention that an HDHP must follow for it to include a pre-tax health savings account (HSA), and how this restriction limits the effectiveness of current plans. A potential solution - allowing HSA-eligible HDHPs to provide first-dollar coverage for targeted, evidence-based, secondary preventive services that prevent chronic disease progression and related complications - can improve patient-centered outcomes, add efficiency to medical spending, and enhance HDHP attractiveness.A multi-disciplinary research team from the University of Michigan's Center for Value-Based Insurance Design, Harvard Medical School, and the University of Minnesota conducted a multi-part project to investigate the impact of updatingthe definition of prevention for HDHPs to include selected secondary preventive services that are frequently used as health plan quality metrics and included as elements of pay-for-performance programs. Specifically, the project aimed to: 1) determine the premium effect, actuarial value, and estimated market uptake of the novel HDHP plan that covers these evidence-based services outside the deductible, and 2) explore through interviews whether insurance industry experts found coverage of secondary preventive services a worthwhile endeavor

    Exploring Pd adsorption, diffusion, permeation, and nucleation on bilayer SiO<sub>2</sub>/Ru as a function of hydroxylation and precursor environment: From UHV to catalyst preparation

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    The hydroxylation-dependent permeability of bilayer SiO2 supported on Ru(0001) was investigated by XPS and TDS studies in a temperature range of 100K to 600K. For this, the thermal behavior of Pd evaporated at 100K, which results in surface and sub-surface (Ru-supported) binding arrangements, was examined relative to the extent of pre-hydroxylation. Samples containing only defect-mediated hydroxyls showed no effect on Pd diffusion through the film at low temperature. If, instead, the concentration of strongly bound hydroxyl groups and associated weakly bound water molecules was enriched by an electron-assisted hydroxylation procedure, the probability for Pd diffusion through the film is decreased via a pore-blocking mechanism. Above room temperature, all samples showed similar behavior, reflective of particle nucleation above the film and eventual agglomeration with any metal atoms initially binding beneath the film. When depositing Pd onto the same SiO2/Ru model support via adsorption of [Pd(NH3)4]C2 from alkaline (pH12) precursor solution, we observe notably different adsorption and nucleation mechanisms. The resultant Pd adsorption complexes follow established decomposition pathways to produce model catalyst systems compatible with those created exclusively within UHV despite lacking the ability to penetrate the film due to the increased size of the initial Pd precursor groups

    Development of Simplified Models of Regional Groundwater and Surface Water Flow Processes based on Computational Experiments with Comprehensive Models

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    The development of complex decision support model systems for the analysis of regional water policies for regions with intense socio-economic development affecting and being affected by the water resources system is of increasing importance. One of the most illustrative examples are regions with open-pit lignite mining. Such model systems have to be based on appropriate submodels, e.g. for water quantity processes. The paper describes submodels for groundwater and surface water flow with special regard to open-pit lignite mining regions. Starting with a problem definition in Section 2 the methodological background is given. The state-of-the-art of comprehensive models of regional water flow processes based on groundwater flow models and of stochastic long-term management modeling are described in details. Section 3 gives the methodological approach for model reduction. The application of this approach is illustrated in Section 4 for the modeling of mine drainage and groundwater tables, for the modeling of remaining pit management and of groundwater-surface water interactions. In the appendix computer programs of some submodels are given being suitable for a more general application
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