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Method for effective dead time measurement in counting systems

Vinagre, F. L. R.; Conde, C. A. N.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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36.76%
The counting losses introduced by the dead time of a counting system are a limiting factor in counting measurements. The purpose of this work is to report an efficient method for the measurement of the effective dead time of a counting system and to characterize its dead time behavior, providing a way to investigate each experimental situation. The method, which we designate as Delayed and Mixed Pulses method, is based on the artificial piling-up of detector pulses with electronic pulses delayed by a specific time interval. It is applicable to the measurement of the effective dead time of a counting system, including both pile-up effects and the dead time characteristics of the elements of the counting chain. With counting systems relying on gaseous radiation detectors, we achieved a standard uncertainty of about 5-10% in the dead times measured.; http://www.sciencedirect.com/science/article/B6TJM-432D95H-V/1/71b31ba2b8d0582c7286bebf941807d8

Análise estatística para dados de contagem longitudinais  na presença de covariáveis: aplicações na área médica; Statistical Analyze For Longitudinal Counting Data in Presence of Covariates: Application in Medical Research

Barros, Emilio Augusto Coelho
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/02/2009 PT
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COELHO-BARROS, E. A. Analise estatstica para dados de contagem longitudinais na presenca de covariaveis: Aplicações na area medica. Dissertação (mestrado) - Faculdade de Medicina de Ribeirão Preto - USP, Ribeirão Preto - SP - Brasil, 2009. Dados de contagem ao longo do tempo na presenca de covariaveis são muito comuns em estudos na area da saude coletiva, por exemplo; numero de doenças que uma pessoa, com alguma caracteristica especifica, adquiriu ao longo de um período de tempo; numero de internações hospitalares em um período de tempo, devido a algum tipo de doença; numero de doadores de orgãos em um período de tempo. Nesse trabalho são apresentados diferentes modelos estatsticos de\fragilidade" de Poisson para a analise estatística de dados de contagem longitudinais. Teoricamente, a distribuição de Poisson exige que a media seja igual a variância, quando isto não ocorre tem-se a presenca de uma variabilidade extra-Poisson. Os modelos estatsticos propostos nesta dissertação incorporam a variabilidade extra-Poisson e capturam uma possvel correlação entre as contagens para o mesmo indivduo. Para cada modelo foi feito uma analise Bayesiana Hierarquica considerando os metodos MCMC (Markov Chain Monte Carlo). Utilizando bancos de dados reais...

Métodos de contagem; Counting methods

Trovão, Marcelo Henrique
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/04/2015 PT
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Neste trabalho, estudamos alguns números e procedimentos que facilitam na solução de problemas no campo da contagem, sendo esses: O Princípio da Inclusão e Exclusão, Triângulo de Pascal, Binômios de Newton, números binomiais e multinomiais, números de funções, permutações, grafos, números de Stirling, lemas de Kaplansky e sequência de Fibonacci.; We studied some numbers and procedures that facilitate the solution of problems in the field of counting, these being: The Principle of Inclusion and Exclusion, Pascal's Triangle, Newton binomial, binomial and multinomial numbers, numbers of functions, permutations, graphs, Stirling numbers, slogans Kaplansky and the Fibonacci sequence.

Detecção e contagem de veículos em vídeos de tráfego urbano; Detecting and counting vehicles in urban traffic video

Barcellos, Pablo Roberlan Manke
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
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Este trabalho apresenta um novo método para o rastreamento e contagem de veículos em vídeos de tráfego urbano. Usando técnicas de processamento de imagens e de agrupamentos de partículas, o método proposto usa coerência de movimento e coerência espacial para agrupar partículas, de modo que cada grupo represente veículos nas sequências de vídeo. Uma máscara contendo os objetos do primeiro plano é criada usando os métodos Gaussian Mixture Model e Motion Energy Images para determinar os locais onde as partículas devem ser geradas, e as regiões convexas dos agrupamentos são então analisadas para verificar se correspondem a um veículo. Esta análise leva em consideração a forma convexa dos grupos de partículas (objetos) e a máscara de foreground para realizar a fusão ou divisão dos agrupamentos obtidos. Depois que um veículo é identificado, ele é rastreado utilizando similaridade de histogramas de cor em janelas centradas nas partículas dos agrupamentos. A contagem de veículos acontece em laços virtuais definidos pelo usuário, através da interseção dos veículos rastreados com os laços virtuais. Testes foram realizados utilizando seis diferentes vídeos de tráfego, em um total de 80000 quadros. Os resultados foram comparados com métodos semelhantes disponíveis na literatura...

Renormalization of singular potentials and power counting

Long, B.; van Koick, U.
Fonte: Academic Press Inc. Elsevier B.V. Publicador: Academic Press Inc. Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 1304-1323
ENG
Relevância na Pesquisa
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We use a toy model to illustrate how to build effective theories for singular potentials. We consider a central attractive 1/r(2) potential perturbed by a 1/r(4) correction. The power-counting rule, an important ingredient of effective theory, is established by seeking the minimum set of short-range counterterms that renormalize the scattering amplitude. We show that leading-order counterterms are needed in all partial waves where the potential overcomes the centrifugal barrier, and that the additional counterterms at next-to-leading order are the ones expected on the basis of dimensional analysis. (C) 2008 Elsevier B.V. All rights reserved.

Optimization of an automatic counting system for the quantification of Staphylococcus epidermidis cells in biofilms

Freitas, Ana Isabel; Vasconcelos, Carlos; Vilanova, Manuel; Cerca, Nuno
Fonte: John Wiley and Sons Publicador: John Wiley and Sons
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
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Biofilm formation is recognized as the main virulence factor in a variety of chronic infections. In vitro evaluation of biofilm formation is often achieved by quantification of viable or total cells. However, these methods depend on biofilm disruption, which is often achieved by vortexing or sonication. In this study, we investigated the effects of sonication on the elimination of Staphylococcus epidermidis cell clusters from biofilms grown over time, and quantification was performed by three distinct analytical techniques. Even when a higher number of sonication cycles was used, some stable cell clusters remained in the samples obtained from 48- and 72-h-old biofilms, interfering with the quantification of sessile bacteria by plate counting. On the other hand, the fluorescence microscopy automatic counting system allowed proper quantification of biofilm samples that had undergone any of the described sonication cycles, suggesting that this is a more accurate method for assessing the cell concentration in S. epidermidis biofilms, especially in mature biofilms.

Comparison of the efficacy of biodegradable and non-biodegradable scintillation liquids on the counting of tritium- and [14C]-labeled compounds

Medeiros,R.B.; Godinho,R.O.; Mattos,M.F.S.S.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2003 EN
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The widespread use of ³H and 14C in research has generated a large volume of waste mixed with scintillation liquid, requiring an effective control and appropriate storage of liquid radioactive waste. In the present study, we compared the efficacy of three commercially available scintillation liquids, Optiphase HiSafe 3, Ultima-Gold™ AB (biodegradable) and Insta-Gel-XF (non-biodegradable), in terms of [14C]-glucose and [³H]-thymidine counting efficiency. We also analyzed the effect of the relative amount of water (1.6 to 50%), radioisotope concentration (0.1 to 100 nCi/ml), pH (2 to 10) and color of the solutions (samples containing 0.1 to 1.0 mg/ml of Trypan blue) on the counting efficiency in the presence of these scintillation liquids. There were few significant differences in the efficiency of 14C and ³H counting obtained with biodegradable or non-biodegradable scintillation liquids. However, there was an 83 and 94% reduction in the efficiency of 14C and ³H counting, respectively, in samples colored with 1 mg/ml Trypan blue, but not with 0.1 mg/ml, independent of the scintillation liquid used. Considering the low cost of biodegradable scintillation cocktails and their efficacy, these results show that traditional hazardous scintillation fluids may be replaced with the new safe biodegradable fluids without impairment of ³H and 14C counting efficiency. The use of biodegradable scintillation cocktails minimizes both human and environmental exposure to hazardous solvents. In addition...

Is automated platelet counting still a problem in thrombocytopenic blood?

Oliveira,Raimundo Antônio Gomes; Takadachi,Maria Mariko; Nonoyama,Kimiyo; Barretto,Orlando César de Oliveira
Fonte: Associação Paulista de Medicina - APM Publicador: Associação Paulista de Medicina - APM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2003 EN
Relevância na Pesquisa
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CONTEXT: Reliable platelet counting is crucial for indicating prophylactic platelet transfusion in thrombocytopenic patients. OBJECTIVE: To evaluate the precision and accuracy of platelet counting for thrombocytopenic patients, using four different automated counters in comparison with the Brecher & Cronkite reference method recommended by the International Committee for Standardization in Hematology (ICSH). TYPE OF STUDY: Automated platelet counting assessment in thrombocytopenic patients. SETTING: Hematology Laboratory, Hospital do Servidor Público Estadual de São Paulo, and the Hematology Division of Instituto Adolfo Lutz, São Paulo, SP, Brazil. MAIN MEASUREMENTS: Brecher & Cronkite reference method and four different automated platelet counters. PARTICIPANTS: 43 thrombocytopenic patients with platelet counts of less than 30,000/µl RESULTS: The ADVIA-120 (Bayer), Coulter STKS, H1 System (Technicom-Bayer) and Coulter T-890 automatic instruments presented great precision and accuracy in relation to laboratory thrombocytopenic samples obtained by diluting blood from normal donors. However, when thrombocytopenic patients were investigated, all the counters except ADVIA (which is based on volume and refraction index) showed low accuracy when compared to the Brecher & Cronkite reference method (ICSH). The ADVIA counter showed high correlation (r = 0.947). However...

The Satanic Notations: Counting Classes Beyond #P and Other Definitional Adventures

Vollmer, Heribert ; Hemaspaandra, Lane A.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
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We explore the potentially ``off-by-one' nature of the definitions of counting (#P versus #NP), difference (DP versus DNP), and unambiguous (UP versus UNP; FewP versus FewNP) classes, and make suggestions as to logical approaches in each case. We discuss the strangely differing representations that oracle and predicate models give for counting classes, and we survey the properties of counting classes beyond #P. We ask whether subtracting a #P function from a P function it is no greater than necessarily yields a #P function.

Probabilistic Counting as an Extension to Randomized Count Storage

Van Durme, Benjamin D. (1979 - ); Lall, Ashwin (1980 - )
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
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Previous work by Talbot and Osborne (2007a) explored the use of randomized storage mechanisms in language modeling. These structures trade a small amount of error for significant space savings, enabling the use of larger language models on relatively modest hardware. Going beyond space efficient count storage, here we present the Transition Counter, an extended model for performing space efficient counting over streams of finite length. Theoretical and initial experimental results show the promise of approximate counting in the context of limited space.

Exact and approximate counting of graph objects: independent sets, Eulerian tours, and more

Ge, Qi ; Štefankovič, Daniel ; Galanis, Andreas ; Vigoda, Eric ; Yang, Linji
Fonte: University of Rochester Publicador: University of Rochester
Tipo: Tese de Doutorado Formato: Illustrations:ill.; Number of Pages:xii, 157 leaves
ENG
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Thesis (Ph. D.)--University of Rochester. Dept. of Computer Science, 2012.
Chapters 2-6 were done jointly with Daniel Stefankovic; additional joint authors for Chapter 3 were Andreas Galanis, Eric Vigoda, and Linji Yang.; Counting problems are studied in a variety of areas. For example, enumerative combinatorics, statistics, statistical physics, and artificial intelligence. In this dissertation, we investigate several counting problems, which are subjects of active research. The specific problems considered are: counting independent sets in bipartite graphs (#BIS), computing the partition function of the hard-core model (Hardcore(λ)), counting Eulerian tours (#ET), counting weighted matchings in bipartite graphs (#BipMatch) and related problems, and counting q-colorings (#q-Coloring). We study these problems from the viewpoint of exact counting, i.e., whether one can efficiently compute the answers exactly, as well as the viewpoint of approximability, i.e., whether one can efficiently compute the answers approximately. To tackle #BIS, we create a new graph polynomial: the R2 polynomial. The most interesting property of this polynomial is that it encodes the number of independent sets in bipartite graphs. We investigate properties of the R2 polynomial...

An optical counting technique with vertical hydrodynamic focusing for biological cells

Chiavaroli, Stefano; Newport, David; Woulfe, Bernie
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
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peer-reviewed; A barrier in scaling laboratory processes into automated microfluidic devices has been the transfer of lab based assays: where engineering meets biological protocol. One basic requirement is to reliably and accurately know the distribution and number of biological cells being dispensed. In this study, a novel optical counting technique to efficiently quantify the number of cells flowing into a microtube is presented. REH, B-lymphoid precursor leukaemia, are stained with a fluorescent dye and frames of moving cells are recorded using a CCD camera. The basic principle is to calculate the total fluorescence intensity of the image and to divide it by the average intensity of a single cell. This method allows counting the number of cells with an uncertainty +/- 5%, which compares favourably to the standard biological methodology, based on the manual Trypan Blue assay, which is destructive to the cells and presents an uncertainty in the order of 20%. The use of a microdevice for vertical hydrodynamic focusing, which can reduce the background noise of out of focus cells by concentrating the cells in a thin layer, has further improved the technique. CFD simulation and Confocal Laser Scanning Microscopy images have shown an 82% reduction in the vertical displacement of the cells. For the flow rates imposed during this study...

An improved chord based on counting bloom filter and topology-aware lookup

Zhao, L.; Wu, J.; Shen, H.; Li, Y.; Sang, Y.
Fonte: IEEE Publicador: IEEE
Tipo: Conference paper
Publicado em //2012 EN
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Chord is a popular and successful topology for Peer-to-Peer (P2P) data sharing. However, the conventional chord is challenged by two main drawbacks. First, it fails to consider the physical topology of the P2P network for designing the lookup solution, which may bring tremendous delay to network routing. Second, its performance of is usually limited by the high space complexity of data storage and thus data retrieval may suffer further network delay. In this work, we propose an improved chord based on Counting Bloom Filter and topology aware lookup to address the drawbacks. We first apply counting Bloom filter for data storage to reduce the space complexity. We then develop a topology-aware lookup mechanism to further speed up the search for local resources. Simulation results show that our improved chord scheme is significantly more efficient than the conventional chord method.; Limin Zhao, Jun Wu, Hong Shen, Yidong Li, Yingpeng Sang

Nonlinear Cointegration and Nonlinear Error Correction: Record Counting Cointegration Tests

Escribano, Álvaro; Sipols, Ana E.; Aparicio, Felipe M.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica Formato: text/plain; application/pdf
Publicado em //2006 ENG
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In this article we propose a record counting cointegration (RCC) test that is robust to nonlinearities and certain types of structural breaks. The RCC test is based on the synchronicity property of the jumps (new records) of cointegrated series, counting the number of jumps that simultaneously occur in both series. We obtain the rate of convergence of the RCC statistics under the null and alternative hypothesis. Since the asymptotic distribution of RCC under the null hypothesis of a unit root depends on the short-run dependence of the cointegrated series, we propose a small sample correction and show by Monte Carlo simulation techniques their excellent small sample behaviour. Finally, we apply our new cointegration test statistic to several financial and macroeconomic time series that have certain structural breaks and nonlinearities.

On computing minimal independent support and its applications to sampling and counting

Ivrii, Alexander; Malik, Sharad; Meel, Kuldeep S.; Vardi, Moshe Y.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Journal article; Text; post-print
ENG
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Constrained sampling and counting are two fundamental problems arising in domains ranging from artificial intelligence and security, to hardware and software testing. Recent approaches to approximate solutions for these problems rely on employing SAT solvers and universal hash functions that are typically encoded as XOR constraints of length n/2 for an input formula with n variables. As the runtime performance of SAT solvers heavily depends on the length of XOR constraints, recent research effort has been focused on reduction of length of XOR constraints. Consequently, a notion of Independent Support was proposed, and it was shown that constructing XORs over independent support (if known) can lead to a significant reduction in the length of XOR constraints without losing the theoretical guarantees of sampling and counting algorithms. In this paper, we present the first algorithmic procedure (and a corresponding tool, called MIS) to determine minimal independent support for a given CNF formula by employing a reduction to group minimal unsatisfiable subsets (GMUS). By utilizing minimal independent supports computed by MIS, we provide new tighter bounds on the length of XOR constraints for constrained counting and sampling. Furthermore...

An Examination of Deferred Reference Counting and Cycle Detection

Quinane, Luke
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (Honours) Formato: 1059526 bytes; 2861489 bytes; 609 bytes; 355 bytes; application/pdf; application/postscript; application/octet-stream; application/octet-stream
EN_AU
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Object-oriented programing languages are becoming increasingly important as are managed runtime-systems. An area of importance in such systems is dynamic automatic memory management. A key function of dynamic automatic memory management is detecting and reclaiming discarded memory regions; this is also referred to as garbage collection. A significant proportion of research has been conducted in the field of memory management, and more specifically garbage collection techniques. In the past, adequate comparisons against a range of competing algorithms and implementations has often been overlooked. JMTk is a flexible memory management toolkit, written in Java, which attempts to provide a testbed for such comparisons. This thesis aims to examine the implementation of one algorithm currently available in JMTk: the deferred reference counter. Other research has shown that the reference counter in JMTk performs poorly both in throughput and responsiveness. Several aspects of the reference counter are tested, including the write barrier, allocation cost, increment and decrement processing and cycle-detection. The results of these examinations found the bump-pointer to be 8% faster than the free-list in raw allocation. The cost of the reference counting write barrier was determined to be 10% on the PPC architecture and 20% on the i686 architecture. Processing increments in the write barrier was found to be up to 13% faster than buffering them until collection time on a uni-processor platform. Cycle detection was identified as a key area of cost in reference counting. In order to improve the performance of the deferred reference counter and to contribute to the JMTk testbed...

Flow cytometry reticulocyte counting using acridine orange: validation of a new protocol

Viana,Karina Augusta; Carvalho,Maria das Graças; Dusse,Luci Maria Sant'Ana; Fernandes,Aline Caldeira; Avelar,Renato Sathler; Avelar,Danielle Marquete Vitelli; Carvalho,Beatriz; Ribeiro,Claudia Maria Franco; Antonelli,Lis Ribeiro do Valle; Teixeira,Andrea
Fonte: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia Publicador: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
36.59%
Introduction: Currently, the reticulocyte counting is a challenge for clinical laboratories in Brazil, mainly for the ordinary ones, which still use the manual method. This method has some limitations, since it consists of a laborious method, time consuming, with low accuracy. Objectives: This study has developed and evaluated the performance of a New Laboratory Protocol for flow cytometry (FC) reticulocytes counting using acridine orange (AO) as dye, aiming to standardize a more precise, easy, fast implementation, and low cost protocol. After standardization of the New Protocol (FC/AO), it was compared with the manual method. The results were analyzed according to the recommendations of the National Committee for Clinical Laboratory Standards (NCCLS), now known as Clinical and Laboratory Standards Institute (CLSI), to evaluate the interchangeability of methods in linear regression analysis and paired t test, besides other quality control tests. Conclusion: Based on these results concerning to the correlation between the methods and the tests related to quality control, we can admit that FC/AO for reticulocyte counting shows undeniable advantages when compared to the preexisting manual method.

Counting and sampling paths in graphs

Hoens, T. Ryan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
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Since Euler began studying paths in graphs, graph theory has become an important branch of mathematics. With all of the research into graph theoretic problems, however, counting – exactly or approximately – the number of simple paths in finite graphs has been neglected. This thesis investigates an approximation technique known as Markov chain Monte Carlo (MCMC) for the specific purpose of approximating the number of simple paths in graphs. Due to the paucity of research into the subject, the thesis will make the conjecture that this cannot be done exactly in an efficient manner (assuming that the longstanding conjecture P 6= NP holds). To this end, the thesis focuses on the relationship between counting and sampling in both weighted and unweighted complete graphs, trees, and directed acyclic graphs (DAGs). This includes both positive and negative results for sampling, as well as demonstrating how counting and sampling are intimately related problems.

Ulterior Reference Counting: Fast Garbage Collection without a Long Wait

Blackburn, Stephen; McKinley, Kathryn
Fonte: Association for Computing Machinery Inc (ACM) Publicador: Association for Computing Machinery Inc (ACM)
Tipo: Conference paper
Relevância na Pesquisa
36.8%
General purpose garbage collectors have yet to combine short pause times with high throughput. For example, generational collectors can achieve high throughput. They have modest average pause times, but occasionally collect the whole heap and consequently incur long pauses. At the other extreme, concurrent collectors, including reference counting, attain short pause times but with significant performance penalties. This paper introduces a new hybrid collector that combines copying generational collection for the young objects and reference counting the old objects to achieve both goals. It restricts copying and reference counting to the object demographics for which they perform well. Key to our algorithm is a generalization of deferred reference counting we call Ulterior Reference Counting. Ulterior reference counting safely ignores mutations to select heap objects. We compare a generational reference counting hybrid with pure reference counting, pure mark-sweep, and hybrid generational mark-sweep collectors. This new collector combines excellent throughput, matching a high performance generational mark-sweep hybrid, with low maximum pause times.

A comparison of research output counting methods using a national CRIS – effects at the institutional level

Chudlarský, Tomáš; Dvořák, Jan; Souček, Martin
Fonte: euroCRIS Publicador: euroCRIS
Tipo: Conference Paper
EN
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Delivered at the CRIS2014 Conference in Rome; published in Procedia Computer Science 33 (Jul 2014).-- 6 pages.; Recent decades have seen a trend towards scientific publications with many authors. There is not an agreed way of counting coauthored publications. This research in progress contribution compares the behaviour of four representative methods of counting research outputs. We present differences between those methods of counting evaluated at the level of whole universities, their faculties, or non-university research institutes. Our study uses publication metadata from a national CRIS.