Wavelets and wavelet packets have recently emerged as powerful tools for signal compression. Wavelet and wavelet packet-based compression algorithms based on embedded zerotree wavelet (EZW) coding are developed for electrocardiogram (ECG) signals, and eight different wavelets are evaluated for their ability to compress Holter ECG data. Pilot data from a blind evaluation of compressed ECG's by cardiologists suggest that the clinically useful information present in original ECG signals is preserved by 8:1 compression, and in most cases 16:1 compressed ECG's are clinically useful.

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Structure editors allow programmers to edit the tree structure of a program directly. This can have cognitive benefits, particularly for novice and end-user programmers. It also simplifies matters for tool designers, because they do not need to contend with malformed program text.This paper introduces Hazelnut, a structure editor based on a small bidirectionally typed lambda calculus extended with holes and a cursor. Hazelnut goes one step beyond syntactic well-formedness: its edit actions operate over statically meaningful incomplete terms. Naïvely, this would force the programmer to construct terms in a rigid "outside-in" manner. To avoid this problem, the action semantics automatically places terms assigned a type that is inconsistent with the expected type inside a hole. This meaningfully defers the type consistency check until the term inside the hole is finished.Hazelnut is not intended as an end-user tool itself. Instead, it serves as a foundational account of typed structure editing.To that end, we describe how Hazelnut's rich metatheory, which we have mechanized using the Agda proof assistant, serves as a guide when we extend the calculus to include binary sum types. We also discuss various interpretations of holes, and in so doing reveal connections with gradual typing and contextual modal type theory, the Curry-Howard interpretation of contextual modal logic. Finally, we discuss how Hazelnut's semantics lends itself to implementation as an event-based functional reactive program. Our simple reference implementation is written using js_of_ocaml.

Statement coverage is commonly used as a measure of test suite quality. Coverage is often used as a part of a code review process: if a patch decreases overall coverage, or is itself not covered, then the patch is scrutinized more closely. Traditional studies of how coverage changes with code evolution have examined the overall coverage of the entire program, and more recent work directly examines the coverage of patches (changed statements). We present an evaluation much larger than prior studies and moreover consider a new, important kind of change-coverage changes of unchanged statements. We present a large-scale evaluation of code coverage evolution over 7,816 builds of 47 projects written in popular languages including Java, Python, and Scala. We find that in large, mature projects, simply measuring the change to statement coverage does not capture the nuances of code evolution. Going beyond considering statement coverage as a simple ratio, we examine how the set of statements covered evolves between project revisions. We present and study new ways to assess the impact of a patch on a project's test suite quality that both separates coverage of the patch from coverage of the non-patch, and separates changes in coverage from changes in the set of statements covered. CCS CONCEPTS • Software and its engineering → Software testing and debugging;

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Purpose In response to the evolving COVID-19 pandemic, many universities have transitioned to online instruction. With learning promising to be online, at least in part, for the near future, instructors may be thinking of providing online collaborative learning opportunities to their students who are increasingly isolated from their peers because of social distancing guidelines. This paper aims to provide design recommendations for online collaborative project-based learning exercises based on this research in a software engineering course at the university level. Design/methodology/approach Through joint work between learning scientists, course instructors and software engineering practitioners, instructional design best practices of alignment between the context of the learners, the learning objectives, the task and the assessment are actualized in the design of collaborative programming projects for supporting learning. The design, first segments a short real-time collaborative exercise into tasks, each with a problem-solving phase where students participate in collaborative programming, and a reflection phase for reflecting on what they learned in the task. Within these phases, a role-assignment paradigm scaffolds collaboration by assigning groups of four students to four complementary roles that rotate after each task. Findings By aligning each task with granular learning objectives, significant pre- to post-test learning from the exercise as well as each task is observed. Originality/value The roles used in the paradigm discourage divide-and-conquer tendencies often associated with collaborative projects. By requiring students to discuss conflicting ideas to arrive at a consensus implementation, their ideas are made explicit, thus providing opportunities for clarifying misconceptions through discussion and learning from the collaboration.

A data adaptive scheme for selecting thresholds for wavelet shrinkage-based noise removal is developed. The method involves a statistical test of hypotheses based on a two-dimensional cumulative sum of wavelet coe cients, which takes into account the coe cients' magnitudes and their relative positions. The amount of smoothing performed during noise removal is controlled by , the usersupplied con dence level of the tests. Simulated critical points for the statistical test are tabulated for a wide range of signal sizes and con dence levels. Results are shown which indicate the scheme performs well on a variety of signals.Keywords| Noise removal, wavelet shrinkage, Brownian sheet stochastic process