Today ontologies are heavily used in the sematic web. As they grow in size reasoning systems can’t work without secondary storage anymore. Thus database technology is required for storing and processing huge ontologies. In this paper we present an efficient technique for representing and reasoning with ontologies in databases. We also present some benchmarking results in comparison with previou...

Data Level Parallelism(DLP) can be exploited in order to improve the performance of processors for certain workload types. There are two main application fields that rely on DLP, multimedia and scientific computing. Most of the existing multimedia vector extensions use sub-word parallelism and wide data paths for processing independent, mainly integer, values in parallel. On the other hand, cla...

Dosimetry in kilovoltage cone beam computed tomography (CBCT) is a challenge due to the limitation of physical measurements. To address this, we used a Monte Carlo (MC) method to estimate the CT dose index (CTDI) and the dose length product (DLP) for a commercial CBCT system. As Dixon and Boone showed that CTDI concept can be applicable to both CBCT and conventional CT, we evaluated weighted CT...

OBJECTIVE Effective July 1, 2012, CT dose reporting became mandatory in California. We sought to assess radiologist compliance with this legislation and to determine areas for improvement. MATERIALS AND METHODS We retrospectively reviewed reports from all chest CT examinations performed at our institution from July 1, 2012, through June 30, 2013, for errors in documentation of volume CT dose ...

Normal Form Nested (NFN) programs have recently been introduced in order to allow for enriching the syntax of disjunctive logic programs under the answer sets semantics. In particular, heads of rules can be disjunctions of conjunctions, while bodies can be conjunctions of disjunctions. Different to many other proposals of this kind, NFN programs may contain variables, and a notion of safety has...

The objective of this study is to compare radiation doses given to ovarian cancer patients by different computed tomographies (CTs) and to evaluate association between doses and subjective and objective image quality.CT examinations included were performed either on a 16-slice CT, equipped with automatic z-axis tube current modulation, or on a 64-slice CT, equipped with z-axis, xy-axis modulati...

Emerging concerns regarding the hazard from medical radiation including CT examinations has been suggested. The purpose of this study was to observe the longitudinal changes of CT radiation doses of various CT protocols and to estimate the long-term efforts of supervising radiologists to reduce medical radiation. Radiation dose data from 11 representative CT protocols were collected from 12 hos...

Cardiac computed tomography (CT) dosimetry makes use of two radiation parameters: a volume CT dose index (CTDI) and a dose length product (DLP). The volume CTDI quantifies the intensity of the radiation used to perform CT examinations, whereas DLP quantifies the amount of radiation used. CTDI metrics can be converted into patient dose metrics by using dose/CTDI conversion factors. In cardiac CT...