1,337 research outputs found
F1000 recommendations as a new data source for research evaluation: A comparison with citations
F1000 is a post-publication peer review service for biological and medical
research. F1000 aims to recommend important publications in the biomedical
literature, and from this perspective F1000 could be an interesting tool for
research evaluation. By linking the complete database of F1000 recommendations
to the Web of Science bibliographic database, we are able to make a
comprehensive comparison between F1000 recommendations and citations. We find
that about 2% of the publications in the biomedical literature receive at least
one F1000 recommendation. Recommended publications on average receive 1.30
recommendations, and over 90% of the recommendations are given within half a
year after a publication has appeared. There turns out to be a clear
correlation between F1000 recommendations and citations. However, the
correlation is relatively weak, at least weaker than the correlation between
journal impact and citations. More research is needed to identify the main
reasons for differences between recommendations and citations in assessing the
impact of publications
Reliability-Based Design of Reinforced Concrete Raft Footings Using Finite Element Method
In this study, a FORTRAN-based reliability-based design program was developed for the design of raft footings based on the ultimate and serviceability design requirements of BS8110 (1997). The well-known analysis of plate on elastic foundation using displacement method of analysis was used in conjunction with the design point method. The design point method was adopted for designing to a pre-determined safety level, T. Example of the design of a raft footing is included to demonstrate the simplicity of the procedure. It was found among other findings that there is a saving of about 64% of longitudinal reinforcement applied at the column face using the proposed method as compared with the BS8110 design method. Also, the depth of footing required using the proposed procedure was found to be 47% lower than in the deterministic method using BS8110. Also, considering a target safety index of 3.0 was found to be cheaper than considering a target safety index of 4.0 for the same loading, material and geometrical properties of the footing. It is therefore concluded that the proposed procedure is quite suitable for application
Querying Schemas With Access Restrictions
We study verification of systems whose transitions consist of accesses to a
Web-based data-source. An access is a lookup on a relation within a relational
database, fixing values for a set of positions in the relation. For example, a
transition can represent access to a Web form, where the user is restricted to
filling in values for a particular set of fields. We look at verifying
properties of a schema describing the possible accesses of such a system. We
present a language where one can describe the properties of an access path, and
also specify additional restrictions on accesses that are enforced by the
schema. Our main property language, AccLTL, is based on a first-order extension
of linear-time temporal logic, interpreting access paths as sequences of
relational structures. We also present a lower-level automaton model,
Aautomata, which AccLTL specifications can compile into. We show that AccLTL
and A-automata can express static analysis problems related to "querying with
limited access patterns" that have been studied in the database literature in
the past, such as whether an access is relevant to answering a query, and
whether two queries are equivalent in the accessible data they can return. We
prove decidability and complexity results for several restrictions and variants
of AccLTL, and explain which properties of paths can be expressed in each
restriction.Comment: VLDB201
Computing a Nonnegative Matrix Factorization -- Provably
In the Nonnegative Matrix Factorization (NMF) problem we are given an nonnegative matrix and an integer . Our goal is to express
as where and are nonnegative matrices of size
and respectively. In some applications, it makes sense to ask
instead for the product to approximate -- i.e. (approximately)
minimize \norm{M - AW}_F where \norm{}_F denotes the Frobenius norm; we
refer to this as Approximate NMF. This problem has a rich history spanning
quantum mechanics, probability theory, data analysis, polyhedral combinatorics,
communication complexity, demography, chemometrics, etc. In the past decade NMF
has become enormously popular in machine learning, where and are
computed using a variety of local search heuristics. Vavasis proved that this
problem is NP-complete. We initiate a study of when this problem is solvable in
polynomial time:
1. We give a polynomial-time algorithm for exact and approximate NMF for
every constant . Indeed NMF is most interesting in applications precisely
when is small.
2. We complement this with a hardness result, that if exact NMF can be solved
in time , 3-SAT has a sub-exponential time algorithm. This rules
out substantial improvements to the above algorithm.
3. We give an algorithm that runs in time polynomial in , and
under the separablity condition identified by Donoho and Stodden in 2003. The
algorithm may be practical since it is simple and noise tolerant (under benign
assumptions). Separability is believed to hold in many practical settings.
To the best of our knowledge, this last result is the first example of a
polynomial-time algorithm that provably works under a non-trivial condition on
the input and we believe that this will be an interesting and important
direction for future work.Comment: 29 pages, 3 figure
Probabilistic methods for wind turbine blades
The European Energy Research Alliance (EERA) has as a key purpose to elevate cooperation between national research institutes to a new level, from ad-hoc participation in joint projects to collectively planning and implementing joint strategic research programmes. The RES directive and the SET Plan enforce a high rate of deployment of wind energy, on- and offshore for the European Union’s member states leading to a high challenge for research in the two priority areas: Integration and Offshore. Wind energy was therefore at an early stage identified as an area for a joint research programme where the key players are the national wind energy research institutes but open to and encouraging universities to participate in the activities
Review of "Internet Addiction among Cyberkids in China" by Qiaolei Jiang
Internet-related addictions constitute a large share of the global cost of mental health-related disorders, diseases, treatment and issues that are estimated to be worth mor than $2.5 trillion in 2019. While focusing on the People's Republic of China (or mainland China) the 2019 publication of "Internet Addiction Among Cyberkids in China: Risk Factors and Intervention Strategies" by Qiaolei Jiang is indeed a welcome addition in the fields of mental health, cyber-psychology, behavioural disorder, and internet addiction treatment
Durability Analysis of Concrete Bridge Deck Exposed to the Chloride Ions Using Direct Optimized Probabilistic Calculation
Durability of reinforced concrete structures is a
deeply discussed problem recently. Concrete structures in
the external environment are very often affected by
chloride ions from de-icing salt or sea water. Chloride ions
penetrate through the concrete cover layer
of the reinforcement and can cause eventually the
corrosion of the steel. However, when estimating the
durability of the structure, it is not sometimes possible to
express the parameters by constant values; therefore, the
probabilistic methods come in handy. Then, the variability
of inputs and outputs can be expressed by histograms. Two
probabilistic approaches were applied in this task – Monte
Carlo simulation with Simulation-Based Reliability
Assessment method, which is widely used for such type of
problems, and the Direct Optimized Probabilistic
Calculation, which is still relatively new type of approach.
The result is a comparison of mentioned methods in terms
of accuracy on the model of one-dimensional chloride
penetration with time independent diffusion coefficient by
using the Fick’s Second Law of Diffusion
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