Some Algorithms for the Conditional Mean Vector and Covariance Matrix

We consider here the problem of computing the mean vector and covariance matrix for a conditional normal distribution, considering especially a sequence of problems where the conditioning variables are changing. The sweep operator provides one simple general approach that is easy to implement and update. A second, more goal-oriented general method avoids explicit computation of the vector and matrix, while enabling easy evaluation of the conditional density for likelihood computation or easy generation from the conditional distribution. The covariance structure that arises from the special case of an ARMA(p, q) time series can be exploited for substantial improvements in computational efficiency.

Metamodel Instance Generation: A systematic literature review

Modelling and thus metamodelling have become increasingly important in Software Engineering through the use of Model Driven Engineering. In this paper we present a systematic literature review of instance generation techniques for metamodels, i.e. the process of automatically generating models from a given metamodel. We start by presenting a set of research questions that our review is intended to answer. We then identify the main topics that are related to metamodel instance generation techniques, and use these to initiate our literature search. This search resulted in the identification of 34 key papers in the area, and each of these is reviewed here and discussed in detail. The outcome is that we are able to identify a knowledge gap in this field, and we offer suggestions as to some potential directions for future research.Comment: 25 page

Some Algorithms for the Conditional Mean Vector and Covariance Matrix

We consider here the problem of computing the mean vector and covariance matrix for a conditional normal distribution, considering especially a sequence of problems where the conditioning variables are changing. The sweep operator provides one simple general approach that is easy to implement and update. A second, more goal-oriented general method avoids explicit computation of the vector and matrix, while enabling easy evaluation of the conditional density for likelihood computation or easy generation from the conditional distribution. The covariance structure that arises from the special case of an ARMA(p, q) time series can be exploited for substantial improvements in computational efficiency

Fission yeast SWI/SNF and RSC complexes show compositional and functional differences from budding yeast.

SWI/SNF chromatin-remodeling complexes have crucial roles in transcription and other chromatin-related processes. The analysis of the two members of this class in Saccharomyces cerevisiae, SWI/SNF and RSC, has heavily contributed to our understanding of these complexes. To understand the in vivo functions of SWI/SNF and RSC in an evolutionarily distant organism, we have characterized these complexes in Schizosaccharomyces pombe. Although core components are conserved between the two yeasts, the compositions of S. pombe SWI/SNF and RSC differ from their S. cerevisiae counterparts and in some ways are more similar to metazoan complexes. Furthermore, several of the conserved proteins, including actin-like proteins, are markedly different between the two yeasts with respect to their requirement for viability. Finally, phenotypic and microarray analyses identified widespread requirements for SWI/SNF and RSC on transcription including strong evidence that SWI/SNF directly represses iron-transport genes

Sharing the Burden of Ebola Vaccine Related Adverse Events

Based upon past experience with other vaccines, the proposed administration of Ebola vaccines (once testing has been completed) will inevitably result in at least some adverse events that will give rise to legal liabilities of only crudely estimable magnitude at this time. Manufacturers, beneficiary governments (e.g., Guinea, Liberia, Sierra Leone), supporting governments (e.g. U.S., U.K.), individuals suffering adverse events, and populations benefiting from widespread vaccination against the Ebola virus all have a shared interest in recognizing, understanding, and managing potential liability as effectively as possible within the framework of a global public health response. There are multiple options available to the global public health community in addressing potential legal liabilities associated with Ebola vaccines, including (1) requiring manufacturers to pay any valid claims, (2) establishing a sui generis product liability insurance scheme for Ebola vaccine claims, (3) agreeing that beneficiary governments compensate their residents for adverse events, (4) issuing declarations of immunity by beneficiary and supporting governments, (5) calling upon beneficiary governments to appear in judicial proceedings on behalf of manufacturers, and/or (6) creating one or more mechanisms for supporting governments to pay for claims relating to adverse events of Ebola vaccine administration

Sharing the Burden of Ebola Vaccine Related Adverse Events

Based upon past experience with other vaccines, the proposed administration of Ebola vaccines (once testing has been completed) will inevitably result in at least some adverse events that will give rise to legal liabilities of only crudely estimable magnitude at this time. Manufacturers, beneficiary governments (e.g., Guinea, Liberia, Sierra Leone), supporting governments (e.g. U.S., U.K.), individuals suffering adverse events, and populations benefiting from widespread vaccination against the Ebola virus all have a shared interest in recognizing, understanding, and managing potential liability as effectively as possible within the framework of a global public health response. There are multiple options available to the global public health community in addressing potential legal liabilities associated with Ebola vaccines, including (1) requiring manufacturers to pay any valid claims, (2) establishing a sui generis product liability insurance scheme for Ebola vaccine claims, (3) agreeing that beneficiary governments compensate their residents for adverse events, (4) issuing declarations of immunity by beneficiary and supporting governments, (5) calling upon beneficiary governments to appear in judicial proceedings on behalf of manufacturers, and/or (6) creating one or more mechanisms for supporting governments to pay for claims relating to adverse events of Ebola vaccine administration

Legal Preparedness and Ebola Vaccines

On Dec 9, 2014, US Secretary of Health and Human Services Sylvia Burwell issued a declaration under the US Public Readiness and Emergency Preparedness Act to provide immunity from legal claims in the USA related to manufacturing, testing, development, distribution, and administration of three candidate Ebola vaccines except in instances of willful misconduct. Although progress in combating Ebola in west Africa has shifted public attention away from vaccine development and deployment, we should not forget that the management of legal liabilities related to vaccines has been an important subject of discussion between national governments, international organizations, vaccine manufacturers, and other parties who have been engaged in the worldwide response to the Ebola outbreak during the past year

Building Specifications in the Event-B Institution

This paper describes a formal semantics for the Event-B specification language using the theory of institutions. We define an institution for Event-B, EVT, and prove that it meets the validity requirements for satisfaction preservation and model amalgamation. We also present a series of functions that show how the constructs of the Event-B specification language can be mapped into our institution. Our semantics sheds new light on the structure of the Event-B language, allowing us to clearly delineate three constituent sub-languages: the superstructure, infrastructure and mathematical languages. One of the principal goals of our semantics is to provide access to the generic modularisation constructs available in institutions, including specification-building operators for parameterisation and refinement. We demonstrate how these features subsume and enhance the corresponding features already present in Event-B through a detailed study of their use in a worked example. We have implemented our approach via a parser and translator for Event-B specifications, EBtoEVT, which also provides a gateway to the Hets toolkit for heterogeneous specification.Comment: 54 pages, 25 figure

A Simple Complexity Measurement for Software Verification and Software Testing

In this paper, we used a simple metric (i.e. Lines of Code) to measure the complexity involved in software verification and software testing. The goal is then, to argue for software verification over software testing, and motivate a discussion of how to reduce the complexity involved in software verification. We propose to reduce this complexity by translating the software to a simple intermediate representation which can be verified using an efficient verifier, such as Boogie [2]