1,459 research outputs found

    Trellis decoding complexity of linear block codes

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    In this partially tutorial paper, we examine minimal trellis representations of linear block codes and analyze several measures of trellis complexity: maximum state and edge dimensions, total span length, and total vertices, edges and mergers. We obtain bounds on these complexities as extensions of well-known dimension/length profile (DLP) bounds. Codes meeting these bounds minimize all the complexity measures simultaneously; conversely, a code attaining the bound for total span length, vertices, or edges, must likewise attain it for all the others. We define a notion of “uniform” optimality that embraces different domains of optimization, such as different permutations of a code or different codes with the same parameters, and we give examples of uniformly optimal codes and permutations. We also give some conditions that identify certain cases when no code or permutation can meet the bounds. In addition to DLP-based bounds, we derive new inequalities relating one complexity measure to another, which can be used in conjunction with known bounds on one measure to imply bounds on the others. As an application, we infer new bounds on maximum state and edge complexity and on total vertices and edges from bounds on span lengths

    Couples\u27 Conceptualizations of Problems in Couple Therapy

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    While a great deal is known about the problems that clients bring to therapy, little is known about the way in which clients conceptualize problems during the course of couple therapy. Understanding clients’ conceptualizations of problems is important because it provides the therapist with a client-centered context on how to approach discussions about the problems during the course of treatment. This manuscript provides the results of an exploratory qualitative inquiry concerning how clients conceptualize problems during therapy and across the trajectory of treatment. The sample consisted of 26 individuals comprising 13 couples attending couple therapy. Participants completed a semi-structured interview prior to the first and after the second, third, and fourth therapy session. Analysis included grounded theory and discourse analysis. Results suggested that couples approach problems from an individualistic standpoint, they internalize problems, and they expect to recover from problems. The authors discuss how therapists may challenge dominant discourses around problems during couple therapy

    Organizing Compression of Hyperspectral Imagery to Allow Efficient Parallel Decompression

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    family of schemes has been devised for organizing the output of an algorithm for predictive data compression of hyperspectral imagery so as to allow efficient parallelization in both the compressor and decompressor. In these schemes, the compressor performs a number of iterations, during each of which a portion of the data is compressed via parallel threads operating on independent portions of the data. The general idea is that for each iteration it is predetermined how much compressed data will be produced from each thread

    Combined Industry, Space and Earth Science Data Compression Workshop

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    The sixth annual Space and Earth Science Data Compression Workshop and the third annual Data Compression Industry Workshop were held as a single combined workshop. The workshop was held April 4, 1996 in Snowbird, Utah in conjunction with the 1996 IEEE Data Compression Conference, which was held at the same location March 31 - April 3, 1996. The Space and Earth Science Data Compression sessions seek to explore opportunities for data compression to enhance the collection, analysis, and retrieval of space and earth science data. Of particular interest is data compression research that is integrated into, or has the potential to be integrated into, a particular space or earth science data information system. Preference is given to data compression research that takes into account the scien- tist's data requirements, and the constraints imposed by the data collection, transmission, distribution and archival systems

    Special Issue Editorial: Equality, Diversity, and Inclusion in IS Education

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    This editorial piece introduces a special issue of the Journal of Information Systems Education (JISE) on the topic of equality, diversity, and inclusion (EDI) in IS education. A number of contemporary issues are raised, such as inequality and barriers pertaining to gender, ethnicity, disability, sexuality, and socio-economic status. A set of research questions relating to EDI within IS education is set out, thus inviting further work within this important and under-researched area of our field

    Severe acute respiratory syndrome coronavirus 2 and blood safety : an updated review

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    Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus first identified in late 2019 and subsequently declared a worldwide pandemic in March 2020. In this review, we provide an overview of the implications of SARS-CoV-2 for blood safety and sufficiency. Summary: Approximately one-third of SARS-CoV-2 infections are asymptomatic. The reported mean incubation period typically varies from 2 to 11 days, but longer periods up to 22 days have been reported. The blood phase of SARS-CoV-2 appears to be brief and low level, with RNAaemia detectable in only a small proportion of patients, typically associated with more severe disease and not demonstrated to be infectious virus. A small number of presymptomatic and asymptomatic blood phase cases have been reported. Transfusion-transmission (TT) of SARS-CoV-2 has not been reported. Therefore, the TT risk associated with SARS-CoV-2 is currently theoretical. To mitigate any potential TT risk, but more importantly to prevent respiratory transmission in donor centers, blood services can implement donor deferral policies based on travel, disease status, or potential risk of exposure and encourage staff vaccination. Key Messages: The TT risk of SARS-CoV-2 appears to be low. The biggest risk to blood services in the current COVID-19 pandemic is to maintain the sufficiency of the blood supply while minimizing respiratory transmission of SARS-CoV-2 to donors and staff while donating blood

    Acceptance, Communication Mode and Use of Audio Computer- Assisted Self Interview Using Touchscreen to Identify Risk Factors among Pregnant Minority Women

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    This paper evaluates the acceptability, communication mode and use of audio computer-assisted self-interview (A-CASI) among minority pregnant women receiving prenatal care in six Washington, DC sites. A total of 2,913 women were screened for demographic eligibility (18+ years old,gestation, Black/African-American or Hispanic) and risk (smoking, environmental tobacco smoke exposure, depression, intimate partner violence). Questions were displayed on touch screen laptop monitors and heard through earphones. The mean length of time to complete the screener was almost 6 minutes. A-CASI experience, which included difficulty in using the computer, acceptability (enjoyment), and preferred communication mode, was compared across sites, the eligibility and risk groups and a subset of 878 enrolled women for whom educational attainment and receipt of WIC (a proxy for income) were available. Respondents thought A-CASI was not difficult to use and liked using the computer. Black/African-American or Hispanic respondents enjoyed it significantly more than did respondents of other race/ethnicities. Respondents who were demographically eligible, Black/ African-American or Hispanic, or with lower education levels listened to questions significantly more than did their counterparts. Mainly listening or listening and reading does not impact burden in terms of the length of time it took to complete the screener. The acceptance of A-CASI as a screening tool opens the door for more uses of this technology in health-related fields. The laptop computer and headphones provide privacy and mobility so the technology can be used to ask sensitive questions in almost any locale, including busy clinic settings

    GPU Lossless Hyperspectral Data Compression System

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    Hyperspectral imaging systems onboard aircraft or spacecraft can acquire large amounts of data, putting a strain on limited downlink and storage resources. Onboard data compression can mitigate this problem but may require a system capable of a high throughput. In order to achieve a high throughput with a software compressor, a graphics processing unit (GPU) implementation of a compressor was developed targeting the current state-of-the-art GPUs from NVIDIA(R). The implementation is based on the fast lossless (FL) compression algorithm reported in "Fast Lossless Compression of Multispectral-Image Data" (NPO- 42517), NASA Tech Briefs, Vol. 30, No. 8 (August 2006), page 26, which operates on hyperspectral data and achieves excellent compression performance while having low complexity. The FL compressor uses an adaptive filtering method and achieves state-of-the-art performance in both compression effectiveness and low complexity. The new Consultative Committee for Space Data Systems (CCSDS) Standard for Lossless Multispectral & Hyperspectral image compression (CCSDS 123) is based on the FL compressor. The software makes use of the highly-parallel processing capability of GPUs to achieve a throughput at least six times higher than that of a software implementation running on a single-core CPU. This implementation provides a practical real-time solution for compression of data from airborne hyperspectral instruments
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