1,720,984 research outputs found
sj-docx-1-prf-10.1177_02676591211042559 – Supplemental material for Differences in the serum metabolic profile to identify potential biomarkers for cyanotic versus acyanotic heart disease
No full textSupplemental material, sj-docx-1-prf-10.1177_02676591211042559 for Differences in the serum metabolic profile to identify potential biomarkers for cyanotic versus acyanotic heart disease by Suman Vimal, Renuka Ranjan, Surabhi Yadav, Gauranga Majumdar, Balraj Mittal, Neeraj Sinha and Surendra Kumar Agarwal in Perfusion</p
Advanced Concurrency Techniques for Concurrent Data Structures
No full textConcurrent algorithms have gained importance as multi-core machines have become more ubiquitous. Several techniques are employed to enable the construction of such algorithms. We present algorithms for the Group Mutual Exclusion (GME) problem which can be used as an advanced concurrency technique to increase the performance of software built on concurrent data structures. The group mutual exclusion (GME) problem is a generalization of the classical mutual exclusion problem in which every critical section is associated with a type or session. Critical sections belonging to the same session can execute concurrently, whereas critical sections belonging to different sessions must be executed serially. The well-known read-write mutual exclusion problem is a special case of the group mutual exclusion problem. We present a new GME algorithm for an asynchronous shared-memory system under the Cache-Coherent model that, in addition to satisfying
lockout freedom, bounded exit and concurrent entering properties, has O(1) step-complexity when
the system contains no conflicting requests as well as O(1) space-complexity per GME object
when the system contains sufficient number of GME objects. We also present a GME algorithm
for the Distributed Shared Memory model that satisfies above properties and has optimal Remote Memory-Reference complexity. To the best of our knowledge, no existing GME algorithm has
O(1) step-complexity for concurrent entering for either model. The Remote-Memory-Reference
complexity of a request for cache-coherent model is only O(c˙) in the amortized case, where ˙c
denotes the point contention of the request. Experiments indicate that our GME algorithm vastly
outperforms well-known GME algorithms in most, if not all, cases.
We also present a lock-based concurrent algorithm for a strictly-balanced red black tree data structure. Our algorithm can be implemented on hardware directly without requiring any additional system support such as transactional memory. We also make use of several optimizations to improve
the performance of our tree. Our experimental results indicate that our lock-based algorithm for
a strictly balanced binary search tree outperforms other relaxed balanced trees for read-dominated
workloads
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Copy Ahead Segment Ring: an Ephemeral Memtable Design for Distributed LSM Tree
No full textWe present a novel Memtable design for distributed LSM trees that effectively reduces contention between concurrent range scans, writes, and prune operations. This design emphasizes the centralization of the Memtable on Disaggregated Memory to eliminate internode
replication and reduce associated costs. Our approach can be adapted to include fixed-size
page allocation, which helps minimize memory fragmentation within Disaggregated Memory. Our approach builds upon established methodologies like Copy on Write BTree, Hashed
Wheel Timer, Separation of Key & Value, and Single Thread per Partition with Lock Free
Ring Buffer to effectively reduce contention and improve system throughput. By integrating
these proven methodologies into our approach, we have developed a highly effective solution
that leverages extra memory to achieve better throughput under contention. Overall, our
approach represents a significant step towards exploring the potential of large disaggregated
memory to improve the performance of distributed LSM tree databases
Approximate Computing Through Bitwidth Optimization
No full textIn this thesis, we propose an approximate computing methodology based on bit width optimization that reduces the internal signal’s bit widths in behavioral descriptions for HLS, and in particular SystemC in order to trade-off area and delay vs. output error. This methodology is coupled with a novel Binary search strategy for selecting the bit widths of the aforementioned internal signals in order to obtain a trade-off of Pareto-optimal configurations. In order to prove the efficacy of the proposed methodology we have implemented this methodology and tested it on six benchmarks from S2CBench v.2.2. The proposed method is abbreviated as ACdesigns, which are the approximate computing designs with error less than Emax% (tolerable maximum error). These are the designs which are obtained after the bit width reduction. Since these designs use smaller bit widths than the original, they result in less area and delay.
Also, the error, area and running time are all critical parameters to get ACdesigns.
Thus, we study and prove experimentally that the strategy for bit width selection takes less running
time than the brute force and will eventually lead to the optimal area vs. error Pareto-optimal designs.
Finally, we prove that the implementation with the proposed method is on average 20.59% more area
efficient compared to static methods used in commercial HLS Tools and results in better running
time over brute force method
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