Importance Sampling: Intrinsic Dimension and Computational Cost

The basic idea of importance sampling is to use independent samples from a proposal measure in order to approximate expectations with respect to a target measure. It is key to understand how many samples are required in order to guarantee accurate approximations. Intuitively, some notion of distance between the target and the proposal should determine the computational cost of the method. A major challenge is to quantify this distance in terms of parameters or statistics that are pertinent for the practitioner. The subject has attracted substantial interest from within a variety of communities. The objective of this paper is to overview and unify the resulting literature by creating an overarching framework. A general theory is presented, with a focus on the use of importance sampling in Bayesian inverse problems and filtering.Comment: Statistical Scienc

Volatolomics: A broad area of experimentation

Chemical analysis (detection and monitoring) of compounds associated with the metabolic activities of an organism is at the cutting edge of science. Volatile metabolomics (volatolomics) are applied in a broad range of applications including: biomedical research (e.g. disease diagnostic tools, personalized healthcare and nutrition, etc.), toxicological analysis (e.g. exposure tool to environmental pollutants, toxic and hazardous chemical environments, industrial accidents, etc.), molecular communications, forensics, safety and security (e.g. search and rescue operations). In the present review paper, an overview of recent advances and applications of volatolomics will be given. The main focus will be on volatile organic compounds (VOCs) originating from biological secretions of various organisms (e.g. microorganisms, insects, plants, humans) and resulting fusion of chemical information. Bench-top and portable or field-deployable technologies-systems will also be presented and discussed

A text mining approach to trend analysis of research on building information modelling in the Middle East and North Africa

This study describes an ongoing research into using text mining technique to identify trends in research on BIM (building information model/modelling/management) in the Middle East and North Africa (MENA). The described research has collected relevant studies on BIM and analysed changes in the patterns and research trends in the selected research period. The research is conducted by using literature review to justify the research aim and objectives, data collection from publication databases to establish a relevant dataset, and data analysis through text mining to identify the patterns and trends in BIM oriented research in MENA. The above research enabled establishing an original view on patterns and trends in BIM oriented research in the MENA. The text analysis approach developed from the described research can be useful for further research into developing a generic text analysis roadmap (TAR) to facilitate academic research and professional practice by using text mining technique in construction management within BIM pervasive project environment. Based on the preliminary research, this study provides useful information on how to use text mining technique to identify patterns and trends in BIM oriented research in the MENA. Research ndings described in this study can well inform further research in related areas

A lifecycle social network analysis framework for BIM adoption in major construction projects

This study presents a critical review and discussions on the need for a project lifecycle oriented social network analysis (SNA) framework to enhance the effectiveness and efficiency of adopting BIM as a socio-technical subsystem in major construction project delivery. The described research adopted literature review and technical analysis in the context of using SNA to support managerial performance enhancement in BIM pervasive major project environment, and to develop a lifecycle oriented SNA framework at strategic level for major construction project management. Based on a preliminary research, this study rst provides information on how BIM adoption can interact with major construction project stakeholders in such a new socio-technical subsystem with regard to their needs, responsibilities, and possible contributions, and then presents a strategic framework to integrate SNA in major project management. The SNA framework presented here can inform further research and development with regard to managerial activities at tactical and operational level throughout the lifecycle of major construction project where challenges from BIM adoption, which has been forming a new socio-technical subsystem, need to be well tackled in major construction project delivery. The described research originally established a strategic framework for using SNA to enhance managerial performance in BIM pervasive major construction project management. This SNA framework is established through literature review and technical analysis in related areas, and can well inform further research and development to facilitate the adoption of this framework at tactical and operational level for project clients

C-V2X Communications for the Support of a Green Light Optimized Speed Advisory (GLOSA) Use Case, Journal of Telecommunications and Information Technology, 2021, nr 2

Rapid expansion of 5G affects a number of sectors, including vehicular communications relying on cooperative intelligent transportation systems (C-ITS). More specifically, in the context of the Internet of Vehicles (IoV), a particular emphasis is placed on modern cellular V2X (C-V2X) technologies aiming to further improve road safety. This work originates from the detailed scope of the ongoing 5G-DRIVE research project promoting cooperation between the EU and China, with the aim of demonstrating IoV services that rely on vehicle-to-infrastructure (V2I) communications. With the C-V2X approach serving as a point of departure, we analyze and describe a specific green light-optimized speed advisory (GLOSA) use case, for which we provide a detailed descriptive framework, a proposed architectural framework for trials, as well as specific KPIs for the joint assessment of trials between the EU and China. We also discuss the context for performance test procedures to be conducted as part of the intended trials. GLOSA provides end-users with short-term information on upcoming traffic light status to optimize traffic flows, help prevent speed limit violations, improve fuel efficiency, and reduce pollutio

SARS Coronavirus-2 Microneutralisation and Commercial Serological Assays Correlated Closely for Some but Not All Enzyme Immunoassays

Serological testing for SARS-CoV-2-specific antibodies provides important research and diagnostic information relating to COVID-19 prevalence, incidence and host immune response. A greater understanding of the relationship between functionally neutralising antibodies detected using microneutralisation assays and binding antibodies detected using scalable enzyme immunoassays (EIA) is needed in order to address protective immunity post-infection or vaccination, and assess EIA suitability as a surrogate test for screening of convalescent plasma donors. We assessed whether neutralising antibody titres correlated with signal cut-off ratios in five commercially available EIAs, and one in-house assay based on expressed spike protein targets. Sera from recovered patients or convalescent plasma donors who reported laboratory-confirmed SARS-CoV-2 infection (n = 200), and negative control sera collected prior to the COVID-19 pandemic (n = 100), were assessed in parallel. Performance was assessed by calculating EIA sensitivity and specificity with reference to microneutralisation. Neutralising antibodies were detected in 166 (83%) samples. Compared with this, the most sensitive EIAs were the Cobas Elecsys Anti-SARS-CoV-2 (98%) and Vitros Immunodiagnostic Anti-SARS-CoV-2 (100%), which detect total antibody targeting the N and S1 antigens, respectively. The assay with the best quantitative relationship with microneutralisation was the Euroimmun IgG. These results suggest the marker used (total Ab vs. IgG vs. IgA) and the target antigen are important determinants of assay performance. The strong correlation between microneutralisation and some commercially available assays demonstrates their potential for clinical and research use in assessing protection following infection or vaccination, and use as a surrogate test to assess donor suitability for convalescent plasma donation

S-Phenyl 4-meth­oxy­benzothio­ate

In the mol­ecule of the title thio­ester, C14H12O2S, the dihedral angle between the phenyl and benzene rings is 71.8 (3)°. The meth­oxy group is essentially coplanar with the benezene ring to which it is bonded, with an r.m.s. deviation of 0.0065 (5) Å for the non-H atoms involved. In the crystal, weak C—H⋯π inter­actions are present

Hierarchical Bayesian level set inversion

The level set approach has proven widely successful in the study of inverse problems for inter- faces, since its systematic development in the 1990s. Re- cently it has been employed in the context of Bayesian inversion, allowing for the quantification of uncertainty within the reconstruction of interfaces. However the Bayesian approach is very sensitive to the length and amplitude scales in the prior probabilistic model. This paper demonstrates how the scale-sensitivity can be cir- cumvented by means of a hierarchical approach, using a single scalar parameter. Together with careful con- sideration of the development of algorithms which en- code probability measure equivalences as the hierar- chical parameter is varied, this leads to well-defined Gibbs based MCMC methods found by alternating Metropolis-Hastings updates of the level set function and the hierarchical parameter. These methods demon- strably outperform non-hierarchical Bayesian level set methods

Big Earth Data for Cultural Heritage in the Copernicus Era

Digital data is stepping in its golden age characterized by an increasing growth of both classical and emerging big earth data along with trans- and multidisciplinary methodological approaches and services addressed to the study, preservation and sustainable exploitation of cultural heritage (CH). The availability of new digital technologies has opened new possibilities, unthinkable only a few years ago for cultural heritage. The currently available digital data, tools and services with particular reference to Copernicus initiatives make possible to characterize and understand the state of conservation of CH for preventive restoration and opened up a frontier of possibilities for the discovery of archaeological sites from above and also for supporting their excavation, monitoring and preservation. The different areas of intervention require the availability and integration of rigorous information from different sources for improving knowledge and interpretation, risk assessment and management in order to make more successful all the actions oriented to the preservation of cultural properties. One of the biggest challenges is to fully involve the citizen also from an emotional point of view connecting “pixels with people” and “bridging” remote sensing and social sensing