3,711 research outputs found
A New Procedure For Multiple Testing Of Econometric Models
A significant role for hypothesis testing in econometrics involves diagnostic checking. When checking the adequacy of a chosen model, researchers typically employ a range of diagnostic tests, each of which is designed to detect a particular form of model inadequacy. A major problem is how best to control the overall probability of rejecting the model when it is true and multiple test statistics are used. This paper presents a new multiple testing procedure, which involves checking whether the calculated values of the diagnostic statistics are consistent with the postulated model being true. This is done through a combination of bootstrapping to obtain a multivariate kernel density estimator of the joint density of the test statistics under the null hypothesis and Monte Carlo simulations to obtain a p value using this kernel density. We prove that under some regularity conditions, the estimated p value of our test procedure is a consistent estimate of the true p value. The proposed testing procedure is applied to tests for autocorrelation in an observed time series, for normality, and for model misspecification through the information matrix. We find that our testing procedure has correct or nearly correct sizes and good powers, particular for more complicated testing problems. We believe it is the first good method for calculating the overall p value for a vector of test statistics based on simulation.Bootstrapping, consistency, information matrix test, Markov chain Monte Carlo simulation, multivariate kernel density, normality, serial correlation, test vector
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GRIDCC: Real-time workflow system
The Grid is a concept which allows the sharing of resources between distributed communities, allowing each to progress towards potentially different goals. As adoption of the Grid increases so are the activities that people wish to conduct through it. The GRIDCC project is a European Union funded project addressing the issues of integrating instruments into the Grid. This increases the requirement of workflows and Quality of Service upon these workflows as many of these instruments have real-time requirements. In this paper we present the workflow management service within the GRIDCC project which is tasked with optimising the workflows and ensuring that they meet the pre-defined QoS requirements specified upon them
Supporting quality indicators in the UK national health service
Quality indicators for performance
management of the UK National Health Service
have been introduced for general practitioners
(GPs) in order to monitor if they are meeting
their performance targets. Such requirements
impose significant load to GPs’ everyday
operations and any type of software solution that
stores relevant information and addresses
performance indicators can help GPs to justify
their fundholding. In this paper we report on a
way of incorporating the semantics of a set of
quality indicators in a database schema that can
fit any GPs' practice. We concentrate on
indicators that posed problems when creating the
database and we provide a discussion that
justifies our design decisions
Wiring Nanoscale Biosensors with Piezoelectric Nanomechanical Resonators
Nanoscale integrated circuits and sensors will require methods for unobtrusive interconnection with the macroscopic world to fully realize their potential. We report on a nanoelectromechanical system that may present a solution to the wiring problem by enabling information from multisite sensors to be multiplexed onto a single output line. The basis for this method is a mechanical Fourier transform mediated by piezoelectrically coupled nanoscale resonators. Our technique allows sensitive, linear, and real-time measurement of electrical potentials from conceivably any voltage-sensitive device. With this method, we demonstrate the direct transduction of neuronal action potentials from an extracellular microelectrode. This approach to wiring nanoscale devices could lead to minimally invasive implantable sensors with thousands of channels for in vivo neuronal recording, medical diagnostics, and electrochemical sensing
Letter to the Editor. ClearPoint versus frame-based MRI-guided and MRI-verified deep brain stimulation
Modulation of NKG2D expression in human CD8(+) T cells corresponding with tuberculosis drug cure.
BACKGROUND: Biomarkers predicting tuberculosis treatment response and cure would facilitate drug development. This study investigated expression patterns of the co-stimulation molecule NKG2D in human tuberculosis and treatment to determine its potential usefulness as a host biomarker of tuberculosis drug efficacy. METHODS: Tuberculosis patients (n = 26) were recruited in Lahore, Pakistan, at diagnosis and followed up during treatment. Household contacts (n = 24) were also recruited. NKG2D expression was measured by qRT-PCR in RNA samples both ex vivo and following overnight mycobacterial stimulation in vitro. Protein expression of NKG2D and granzyme B was measured by flow cytometry. RESULTS: NKG2D expression in newly diagnosed tuberculosis patients was similar to household contacts in ex vivo RNA, but was higher following in vitro stimulation. The NKG2D expression was dramatically reduced by intensive phase chemotherapy, in both ex vivo blood RNA and CD8(+) T cell protein expression, but then reverted to higher levels after the continuation phase in successfully treated patients. CONCLUSION: The changes in NKG2D expression through successful treatment reflect modulation of the peripheral cytotoxic T cell response. This likely reflects firstly in vivo stimulation by live Mycobacterium tuberculosis, followed by the response to dead bacilli, antigen-release and finally immunopathology resolution. Such changes in host peripheral gene expression, alongside clinical and microbiological indices, could be developed into a biosignature of tuberculosis drug-induced cure to be used in future clinical trials
Digital Trust - Trusted Computing and Beyond A Position Paper
Along with the invention of computers and interconnected networks, physical societal notions like security, trust, and privacy entered the digital environment. The concept of digital environments begins with the trust (established in the real world) in the organisation/individual that manages the digital resources. This concept evolved to deal with the rapid growth of the Internet, where it became impractical for entities to have prior offline (real world) trust. The evolution of digital trust took diverse approaches and now trust is defined and understood differently across heterogeneous domains. This paper looks at digital trust from the point of view of security and examines how valid trust approaches from other domains are now making their way into secure computing. The paper also revisits and analyses the Trusted Platform Module (TPM) along with associated technologies and their relevance in the changing landscape. We especially focus on the domains of cloud computing, mobile computing and cyber-physical systems. In addition, the paper also explores our proposals that are competing with and extending the traditional functionality of TPM specifications
Unified Model for Data Security -- A Position Paper
One of the most crucial components of modern Information Technology (IT) systems is data. It can be argued that the majority of IT systems are built to collect, store, modify, communicate and use data, enabling different data stakeholders to access and use it to achieve different business objectives. The confidentiality, integrity, availability, audit ability, privacy, and quality of the data is of paramount concern for end-users ranging from ordinary consumers to multi-national companies. Over the course of time, different frameworks have been proposed and deployed to provide data security. Many of these previous paradigms were specific to particular domains such as military or media content providers, while in other cases they were generic to different verticals within an industry. There is a much needed push for a holistic approach to data security instead of the current bespoke approaches. The age of the Internet has witnessed an increased ease of sharing data with or without authorisation. These scenarios have created new challenges for traditional data security. In this paper, we study the evolution of data security from the perspective of past proposed frameworks, and present a novel Unified Model for Data Security (UMDS). The discussed UMDS reduces the friction from several cross-domain challenges, and has the functionality to possibly provide comprehensive data security to data owners and privileged users
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