David Spence

Learn More
We describe the XenoSearch system for performing expressive resource discovery searches in a distributed environment. We represent server meta-data, such as their locations and facilities, as points in a multi-dimensional space and then express queries as predicates over these points. Each XenoSearch node holds a portion of this space and the key goal of(More)
The high bandwidth and low latency of the modern internet has made possible the deployment of <i>distributed computing platforms</i>. The <i>XenoServe</i> platform provides a distributed computing platform open to all and presents three major new challenges for resource discovery: Firstly, network location is key for effectively provisioning services, to(More)
CONTEXT Glomerular cysts, defined as Bowman space dilatation greater than 2 to 3 times normal size, are found in disorders of diverse etiology and with a spectrum of clinical manifestations. The term glomerulocystic kidney (GCK) refers to a kidney with greater than 5% cystic glomeruli. Although usually a disease of the young, GCK also occurs in adults. (More)
This paper presents work undertaken to integrate the future UK national Shibboleth infrastructure with the UK's National Grid Service (NGS). Our work, ShibGrid, provides both transparent authentication for portal based Grid access and a credential transformation service for users of other Grid access methods. The ShibGrid support for portal-based(More)
Laryngeal atypical carcinoids (AC/moderately-differentiated neuroendocrine carcinoma) are associated with moderately aggressive clinical behavior; however, a subset of tumors classified as AC have much greater aggressive potential. These tumors fulfill the proposed diagnostic criteria for pulmonary large cell neuroendocrine carcinoma, albeit in the larynx.(More)
Modern magnetic resonance imaging (MRI) systems consist of several complex, high cost subsystems. The cost and complexity of these systems often makes them impractical for use as routine laboratory instruments, limiting their use to hospitals and dedicated laboratories. However, advances in the consumer electronics industry have led to the widespread(More)
Data analysts consider standard regression models (e.g., generalized linear model) or nonparametric smoothing techniques (e.g., loess or splines) when examining the association between two variables. Before this step, a quantile-based summarization is typically used for exploring the exposure-response relationship. Unfortunately, these exploratory(More)
AdaBoost is an efficient method for producing a highly accurate learning algorithm by assembling multiple classifiers, but it is also widely known for its long duration of off-line learning. Especially, when it is applied for feature selection for object detection, its learning process is to exhaustively evaluate every feature in a large set. With the(More)
INTRODUCTION The geometry of the carotid bifurcation has been proposed as a possible risk factor for atherosclerosis, by virtue of the purported role of local hemodynamics in early stages of atherosclerotic plaque development [1]. In this context it is of interest to study asymptomatic subjects with mild carotid artery disease. Instead, investigations of(More)