30,756 research outputs found
Instructional strategies and tactics for the design of introductory computer programming courses in high school
This article offers an examination of instructional strategies and tactics for the design of introductory computer programming courses in high school. We distinguish the Expert, Spiral and Reading approach as groups of instructional strategies that mainly differ in their general design plan to control students' processing load. In order, they emphasize topdown program design, incremental learning, and program modification and amplification. In contrast, tactics are specific design plans that prescribe methods to reach desired learning outcomes under given circumstances. Based on ACT* (Anderson, 1983) and relevant research, we distinguish between declarative and procedural instruction and present six tactics which can be used both to design courses and to evaluate strategies. Three tactics for declarative instruction involve concrete computer models, programming plans and design diagrams; three tactics for procedural instruction involve worked-out examples, practice of basic cognitive skills and task variation. In our evaluation of groups of instructional strategies, the Reading approach has been found to be superior to the Expert and Spiral approaches
GUBS, a Behavior-based Language for Open System Dedicated to Synthetic Biology
In this article, we propose a domain specific language, GUBS (Genomic Unified
Behavior Specification), dedicated to the behavioral specification of synthetic
biological devices, viewed as discrete open dynamical systems. GUBS is a
rule-based declarative language. By contrast to a closed system, a program is
always a partial description of the behavior of the system. The semantics of
the language accounts the existence of some hidden non-specified actions
possibly altering the behavior of the programmed device. The compilation
framework follows a scheme similar to automatic theorem proving, aiming at
improving synthetic biological design safety.Comment: In Proceedings MeCBIC 2012, arXiv:1211.347
Polly's Polyhedral Scheduling in the Presence of Reductions
The polyhedral model provides a powerful mathematical abstraction to enable
effective optimization of loop nests with respect to a given optimization goal,
e.g., exploiting parallelism. Unexploited reduction properties are a frequent
reason for polyhedral optimizers to assume parallelism prohibiting dependences.
To our knowledge, no polyhedral loop optimizer available in any production
compiler provides support for reductions. In this paper, we show that
leveraging the parallelism of reductions can lead to a significant performance
increase. We give a precise, dependence based, definition of reductions and
discuss ways to extend polyhedral optimization to exploit the associativity and
commutativity of reduction computations. We have implemented a
reduction-enabled scheduling approach in the Polly polyhedral optimizer and
evaluate it on the standard Polybench 3.2 benchmark suite. We were able to
detect and model all 52 arithmetic reductions and achieve speedups up to
2.21 on a quad core machine by exploiting the multidimensional
reduction in the BiCG benchmark.Comment: Presented at the IMPACT15 worksho
Finite Countermodel Based Verification for Program Transformation (A Case Study)
Both automatic program verification and program transformation are based on
program analysis. In the past decade a number of approaches using various
automatic general-purpose program transformation techniques (partial deduction,
specialization, supercompilation) for verification of unreachability properties
of computing systems were introduced and demonstrated. On the other hand, the
semantics based unfold-fold program transformation methods pose themselves
diverse kinds of reachability tasks and try to solve them, aiming at improving
the semantics tree of the program being transformed. That means some
general-purpose verification methods may be used for strengthening program
transformation techniques. This paper considers the question how finite
countermodels for safety verification method might be used in Turchin's
supercompilation method. We extract a number of supercompilation sub-algorithms
trying to solve reachability problems and demonstrate use of an external
countermodel finder for solving some of the problems.Comment: In Proceedings VPT 2015, arXiv:1512.0221
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