24,714 research outputs found
Track and Vertex Reconstruction on GPUs for the Mu3e Experiment
No full textThe Mu3e experiment searches for the lepton flavour violating decay μ → eee , aiming at a branching ratio sensitivity of 10 − 16 . A high precision tracking detector combined with timing detectors will measure the momenta, vertices and timing of the decay products of more than 10 9 muons/s stopped in the target. The trigger-less readout system will deliver about 100 GB/s of data. The implementation of a 3D tracking algorithm on a GPU is presented for usage in the online event selection. Together with a vertex fit this will allow for a reduction of the output data rate to below 100 M
Status of the Mu3e Experiment at PSI
No full textThe Mu3e experiment aims to search for the lepton-flavour violating decay with a sensitivity to one signal decay in muon decays at a muon stopping rate of . With currently available rates of , a sensitivity on the branching ratio of is the aim of the first phase. This will allow for tests of new physics models with enhanced branching ratios for lepton-flavour violating processes with an unprecedented precision. The experiment must be operated at very high muon rates all the while suppressing the background of the decay and accidental electron-positron combinations. Therefore, a tracking detector made of thin pixel sensors with additional scintillating fibres and tiles for precise time measurement will be built. The development of the subdetectors is ongoing while detector construction is still in preparation
The Structure of Scientific Collaboration Networks in Scientometrics
Get PDFThe structure of scientific collaboration networks in scientometrics was investigated at the level of individuals by using bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation Index (SCI) during 1978 to 2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis and frequency analysis of words was explored to reveal: (1) The microstructure of the collaboration network on scientists’ aspects of scientometrics; (2) The major collaborative fields of the collaborative sub-networks; (3) The collaborative center of the collaboration network in scientometrics
Collaboration in Iranian Scientific Publications
No full textThis study looks at international collaboration in Iranian scientific publications through the ISI Science Citation Index® (SCI) for the years 1995-1999, inclusive. These results are compared to and contrasted with the earlier findings for the periods covering 1985-1994 (Osareh & Wilson 2000). The results of Iran's increasing productivity over a 15-year period are presented. Iran doubled its output in the first two five-year periods and increased 2.8-fold from the second to the third five-year period. The rise in Iran's scientific publication output is due mainly to factors such as the ending of the war, better economic conditions, recent changes in the Iranian government's policy, basic changes in the political environment brought about by the Reformers, expansion of the Iranian presses for national publications, and the recent return of a large number of students trained overseas through government scholarships. External changes also account for the increased productivity, e.g., the acceptance of three Iranian source journals by the SCI, increased access to international databases through the Internet and better electronic communication facilities for international collaboration. One of the most important and significant factors that caused this dramatic rise seems to be the government's research policies in the last few years. Since 1999, the Iran Science, Research and Technology Ministry, has encouraged researchers to publish their non-Farsi language articles in highly ranked international scientific journals, for example, by giving prizes to researchers who publish their articles in ISI-ranked journals
The methodological status of co-authorship networks
No full textA powerful strategy within the study of collaboration
in science is to posit that co-authorship patterns
represent social networks.
It is prerequisite to an application of Social
Network Analysis (SNA) to define the network
entities. A network analysis of the inter-institutional
collaboration in COLLNET on the basis
of co-authorships was conducted. The study reveals
that it is crucial whether the co-authorship
itself is seen as an author's relational property or
as a social event that brings the authors together.
The former possibility is represented by a onemode
network in which each author can be related
to each other author. Quite distinct from
that are two-mode networks, the latter approach.
They consist of two single data sets in which relations
are only possible between different sets.
Different modes of representations require
different network approaches. One is that co-authorship
networks are seen as one-mode networks,
which has the advantage of the application
of a variety of measures. In contrast, twomode
networks, the other option, cannot be analysed
by standard techniques but its distinctive
features demand a new conceptualisation of
measures. In conclusion, the two-mode perspective
is more promising because it allows a dual
perspective on collaboration in science which includes
researchers as well as their scientific output
Co-authorship Network of Scientometrics Research Collaboration
Get PDFThis paper examines the co-authorship network in the field of scientometrics using social network analysis techniques with the aim of developing an understanding of research collaboration in this scientific community. Using co-authorship data from 3125 articles published in the journal Scientometrics with a time span of more than three decades (1980-2012), we construct an evolving co-authorship network and calculate three centrality measures (closeness, betweenness, and degree) for 3024 authors, 1207 institutions, 68 countries and 22 academic fields in this network. This paper also discusses the usability of centrality measures in author ranking, and suggests that centrality measures can be useful indicators for impact analysis. Findings revealed that scientometrics was not dominated by a couple of key researchers as quite a significant number of popular researchers were identified. The United States occupies the topmost position in all measures except for degree centrality. The most active, central and collaborative academic discipline in scientometrics is Information & Library Science
Das HV-MAPS basierte MuPix Teleskop
No full textDas Mu3e-Experiment sucht nach dem Zerfall eines Myons in zwei Positronen und einem Elektron, welcher nach dem Standardmodell sehr stark unterdrückt und somit nicht beobachtbar ist. Um die geplante Sensitivität von einem in 1016 zu erreichen, müssen 109 Myonenzerfälle pro Sekunde beobachtet werden. Der Spurdetektor wird aus mit Hochspannung betriebenen dünnen monolithischen aktiven Pixelsensoren (HV-MAPS) gebaut. Da diese auf bis zu 50 µm gedünnt werden können, eignen sie sich ideal um niederenergetische Teilchen zu detektieren. Der aktelle Sensorprototyp ist der MuPix7. Um die Detektorkomponenten und die Datennahme des Mu3e-Detektors zu testen wurde ein Strahlteleskop aus HV-MAPS realisiert. Dieses wurde für den Einsatz an verschiedenen Standorten optimiert, basiert auf optomechanischen Komponenten und zeichnet sich durch hohe Flexibilität und schnellen Aufbau sowie Kalibration aus.In diesem Vortrag werden die Funktionsweise des Teleskops, Testergebnisse aus drei Teststrahlkampagnen, bei denen Trefferraten von 1 MHz erreicht wurden, sowie aktuelle Leistungsverbesserungen vorgestellt
Searching for Charged Lepton Flavour Violation with Mu3e
Get PDFThe observation of lepton flavour violation (LFV) in the charged lepton
sector would be an unambiguous sign of physics beyond the Standard Model (BSM),
and thus, it is the channel of choice for many BSM searches. LFV searches in
muon decays in particular benefit from the fact that muons can be easily
produced at high rates. There is a global effort to search for LFV at
high-intensity muon sources to which the upcoming Mu3e experiment at the Paul
Scherrer Institute (PSI) will contribute. The Mu3e Collaboration aims to
perform a background-free search for the LFV decay with an
unprecedented sensitivity in the order of in the first phase of
operation and in the final phase - an improvement over the preceding
SINDRUM experiment by four orders of magnitude. The high muon stopping rates
and low momenta of the decay electrons make high demands on momentum and time
resolution and on the data acquisition. The innovative experimental concept is
based on a tracking detector built from novel ultra-thin silicon pixel sensors
and scintillating fibres and tiles as well as online event reconstruction and
filtering in real time.Comment: 6 pages, 5 figures, proceedings of the 23rd International Workshop on
Neutrinos from Accelerators (NuFACT 2022
Measuring author influence in scientific collaboration networks
No full text
Purpose: The purpose of this paper is to measure author influence in scientific collaboration networks by considering the combined effects of multiple indexes. In the meanwhile, we intend to explore a method to avoid assigning subjective weights.
Design/methodology/approach: We applied four centrality measures (degree centrality, betweenness centrality, closeness centrality and eigenvector centrality) and authors' published papers to the scientific collaboration network. The grey relational analysis (GRA) method based on information entropy was used to measure an author's impact in the collaboration network. The weight of each evaluation index was determined based on information entropy. The ACM SIGKDD collaboration network was selected as an example to demonstrate the practicality and effectiveness of our method.
Findings: Author influence was not always positively correlated with evaluation indexes such as degree centrality and betweenness centrality. This implies that combined effects of multiple indexes should be considered in author impact analysis. The introduction of the GRA method based on information entropy can reduce the interference of human factors in the evaluation process.
Research limitations: We only analyzed author influence from the perspective of scientific collaboration, but the impact of citation on author influence was ignored.
Practical implications: The proposed method can be also applied to detect influential authors in bibliographic co-citation network, author co-citation network, bibliographic coupling network or author coupling network. It would help facilitate scientific collaboration and enhance scholarly communication.
Originality/value: This paper proposes an analytical method of evaluating author influence in scientific collaboration networks, in which combined effects of multiple indexes are considered and the interference of human factors is reduced in the evaluation process.
Purpose: The purpose of this paper is to measure author influence in scientific collaboration networks by considering the combined effects of multiple indexes. In the meanwhile, we intend to explore a method to avoid assigning subjective weights.
Design/methodology/approach: We applied four centrality measures (degree centrality, betweenness centrality, closeness centrality and eigenvector centrality) and authors' published papers to the scientific collaboration network. The grey relational analysis (GRA) method based on information entropy was used to measure an author's impact in the collaboration network. The weight of each evaluation index was determined based on information entropy. The ACM SIGKDD collaboration network was selected as an example to demonstrate the practicality and effectiveness of our method.
Findings: Author influence was not always positively correlated with evaluation indexes such as degree centrality and betweenness centrality. This implies that combined effects of multiple indexes should be considered in author impact analysis. The introduction of the GRA method based on information entropy can reduce the interference of human factors in the evaluation process.
Research limitations: We only analyzed author influence from the perspective of scientific collaboration, but the impact of citation on author influence was ignored.
Practical implications: The proposed method can be also applied to detect influential authors in bibliographic co-citation network, author co-citation network, bibliographic coupling network or author coupling network. It would help facilitate scientific collaboration and enhance scholarly communication.
Originality/value: This paper proposes an analytical method of evaluating author influence in scientific collaboration networks, in which combined effects of multiple indexes are considered and the interference of human factors is reduced in the evaluation process.</div
Inter-institutional scientific collaboration: an approach from social network
Get PDFThis paper presents a tool that can be used to characterize, analyze and interpret the
patterns of collaboration among institutions by means of the visual display of scientific
information. These graphic representations allow for a combined analysis of a given
institution in the system of relations (network), and of the particular attributes of that
institution (indicators). The tool affords the possibility of regenerating the network to
make any number of aggregates appear or disappear, thus allowing one to focus on
institutional sectors, geographic regions, etc. It also allows for analysis of sectorial
interaction, institutional backing of research, and the influence of geographic proximity,
linguistic affinity, or regional politics. This is indeed a versatile analytical tool, and it is
bound to prove its potential for evaluating patterns of collaborative research, development
and innovation
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