Employment transitions have been shown to be an important predictor of the decision to either enter or exit the Supplemental Nutrition Assistance program (SNAP). However, little is known about how the associations bet...
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Employment transitions have been shown to be an important predictor of the decision to either enter or exit the Supplemental Nutrition Assistance program (SNAP). However, little is known about how the associations between losing a job and entering the program, or between obtaining a job and leaving the program differ by individuals more long-term employment experiences. This article uses a sample from the Survey of Income and program Participation, collected from 2001 to 2003, to examine how long-term instability in employment affects the association between employment transitions and the decision to enter and exit SNAP. Empirical models of program entry and exit are estimated for a full sample and for family subgroups of particular interest to program policy-makers. Our results provide evidence that employment changes are more strongly associated with program entry and exit for individuals who are less accustomed to experiencing fluctuations in employment than those who are more accustomed to experiencing these fluctuations.
This article is a survey of program visualization systems intended for teaching beginners about the runtime behavior of computer programs. Our focus is on generic systems that are capable of illustrating many kinds of...
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This article is a survey of program visualization systems intended for teaching beginners about the runtime behavior of computer programs. Our focus is on generic systems that are capable of illustrating many kinds of programs and behaviors. We inclusively describe such systems from the last three decades and review findings from their empirical evaluations. A comparable review on the topic does not previously exist;ours is intended to serve as a reference for the creators, evaluators, and users of educational program visualization systems. Moreover, we revisit the issue of learner engagement which has been identified as a potentially key factor in the success of educational software visualization and summarize what little is known about engagement in the context of the generic program visualization systems for beginners that we have reviewed;a proposed refinement of the frameworks previously used by computing education researchers to rank types of learner engagement is a side product of this effort. Overall, our review illustrates that program visualization systems for beginners are often short-lived research prototypes that support the user-controlled viewing of program animations;a recent trend is to support more engaging modes of user interaction. The results of evaluations largely support the use of program visualization in introductory programming education, but research to date is insufficient for drawing more nuanced conclusions with respect to learner engagement. On the basis of our review, we identify interesting questions to answer for future research in relation to themes such as engagement, the authenticity of learning tasks, cognitive load, and the integration of program visualization into introductory programming pedagogy.
A characterization of program referencing dynamics based on the temporal behavior of memory demand (as represented by the working set size of a program for a given window size) is proposed. A deterministic generative ...
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A characterization of program referencing dynamics based on the temporal behavior of memory demand (as represented by the working set size of a program for a given window size) is proposed. A deterministic generative model which produces a references string having a given dynamic characterization is then presented, and its practical implementation is discussed. An experimental study of the accuracy and the viability of such a model is performed, together with a theoretical and empirical investigation of the feasibility of constructing a synthetic program which produces an approximation to that artificial string, thereby exhibiting the given dynamic behavior. The results for working-set-like environments with window sizes larger than or equal to that used in the generation of the artificial string are satisfactory, but those for other types of memory policies reveal that improvements to the string generation algorithm or different characterizations are needed.
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