666 research outputs found
Remote detection of boundary-layer transition by an optical system
This instrument development program was funded because of the urgent need to measure boundary-layer transition in wind tunnels. In the course of this development program, a prototype was designed, built, and tested. Recent transonic experiments in the Boeing Model Transonic Wind Tunnel show that the interferometer results correlate very well with sublimating chemical tests
Image findings of cranial nerve pathology on [18F]-2- deoxy-D-glucose (FDG) positron emission tomography with computerized tomography (PET/CT): a pictorial essay.
This article aims to increase awareness about the utility of (18)F -FDG-PET/CT in the evaluation of cranial nerve (CN) pathology. We discuss the clinical implication of detecting perineural tumor spread, emphasize the primary and secondary (18)F -FDG-PET/CT findings of CN pathology, and illustrate the individual (18)F -FDG-PET/CT CN anatomy and pathology of 11 of the 12 CNs
Heuristic Approach for Scheduling Dependent Real-Time Tasks
Reducing energy consumption is a critical issue in the design of battery-powered real time systems to prolong battery life. With dynamic voltage scaling (DVS) processors, energy consumption can be reduced efficiently by making appropriate decisions on the processor speed/voltage during the scheduling of real time tasks. Scheduling decision is usually based on parameters which are assumed to be crisp. However, in many circumstances the values of these parameters are vague. The vagueness of parameters suggests that to develop a fuzzy logic approach to reduce energy consumption by determining the appropriate supply-voltage/speed of the processor provided that timing constraints are guaranteed. Intensive simulated experiments and qualitative comparisons with the most related literature have been conducted in the context of dependent real-time tasks. Experimental results have shown that the proposed fuzzy scheduler saves more energy and creates feasible schedules for real time tasks. It also considers tasks priorities which cause higher system utilization and lower deadline miss time
Peritoneal Mouse as Detected on 18F-FDG PET-CT
We present the case of a 77-year-old male with a history of prostate cancer. Follow up PET-CT and contrast-enhanced CT demonstrated a small peritoneal loose body or “mouse” in the pelvis. This is an uncommon, benign, asymptomatic finding which is usually incidentally discovered. The significance of being aware of this entity is to distinguish it from metastasis, especially in patients with known abdominal and pelvic malignancies
FDG Dose Extravasations in PET/CT: Frequency and Impact on SUV Measurements
Objectives: Positron emission tomography (PET)/CT with 18F-FDG has proven to be effective in detecting and assessing various types of cancers. However, due to cancer and/or its therapy, intravenous (IV) FDG injection may be problematic resulting in dose extravasations. In the most frequently used field of view (FOV), arms-up, and base of skull to upper thigh [limited whole body (LWB)], the injection site may not be routinely imaged. The purpose of this study was to evaluate the frequency of dose extravasations in FDG PET and the potential impact on standard uptake value (SUV) measurements. Methods: True whole body FDG PET/CT scans (including all extremities) of 400 patients were retrospectively reviewed. A log recorded cases of IV dose extravasations. When possible, SUVs were measured in two frequently used reference locations: mediastinum and liver. The SUVs were obtained in the same patients who had studies with and without FDG extravasations within an average of 3 months without interval therapy. Results: Of the 400 scans, 42 (10.5%) had extravasations on the maximum intensity projections images. In scans with or without dose infiltration, FDG injection site was at or distal to the antecubital fossa in 97% of studies. Of those 42 cases, dose infiltration was within the LWB FOV in 29/42 (69%) and outside in the remaining 13/42 (31%). Of those 42 patients, 5 had repeat PET studies with no interval therapy. For those 5 patients, liver maximum SUV was 11.7% less in patients with infiltration than those without (2.22 ± 0.54 vs. 2.48 ± 0.6). Mediastinum SUVmax was 9.3% less in patients with infiltration than those without (1.72 ± 0.54 vs. 1.88 ± 0.49). Conclusion: We conclude dose extravasations were commonly encountered (10.5%) in PET/CT. However, it is underreported by at least 31% due to omitting injection site from the FOV. When present, extravasations may lead to underestimation of SUVmax. Therefore, it should not only be avoided but also reported in order to avoid false interpretations of the exam
Big Data Analytics Impact Transformation
The study aimed at evaluating the applications of big data analytics in enhancing the transformation of the global economy. The sample for this study consisted of consultants who are familiar with big data and transformation in marketing. A total of 396 consultants were sent the study questionnaire to participate in the online survey, of which 118 participants commenced the survey. Companies need such input because only half of them create business events and only a quarter calculate key performance indicators such as profitability. One can only wonder whether there is in fact a wide demand for this classification. From a realistic point of view, it may not matter whether the change is radical or transformative, the real impact is more important. Furthermore, the anticipated increase in post-purchase boost is in line with previous studies which mention that companies can offer precise customer service using the new interface. Findings are not astounding as we see such modifications taking place. The popularity of mobile and social applications facilitates customers to access product and service information in a variety of ways when needed, which further augments their product and service awareness. This study shows increased expectations for the use of automation and self-service communication between institutions and customers. The results assured that businesses need such input to be a starting point for firms to verify their business issues
The Relation Between Rough Sets And Fuzzy Sets Via Topological Spaces
Abstract: Theories of rough sets and fuzzy sets are related and complementary methodologies to handle uncertainty of vagueness and coarseness, respectively. They are generalizations of classical set theory for modeling vagueness and uncertainty. A fundamental question concerning both theories is their connections and differences. There have been many studies on this topic. Topology is a branch of mathematics, whose ideas exist not only in almost all branches of mathematics but also in many real life applications. The topological structure on an abstract set is used as the base, which used to extract knowledge from data. In this paper: topological structure is used to study the relation between rough sets and fuzzy sets. Membership function is used to convert from rough set to fuzzy set and vice versa. This conversion will achieve the advantages of two theories. Some examples and theories are introduced to indicate the importance of using general binary relations in the construction of rough set concepts, and indicate the relation between rough sets and fuzzy sets according to the topological spaces
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Cyclicality and Firm-size in Private Firm Defaults
The Basel II/III and CRD-IV Accords reduce capital charges on bank loans to smaller firms by assuming that the default probabilities of smaller firms are less sensitive to macroeconomic cycles. We test this assumption in a default intensity framework using a large sample of bank loans to private Danish firms. We find that controlling only for size, the default probabilities of small firms are, in fact, less cyclical than the default probabilities of large firms. However, accounting for firm characteristics other than size, we find that the default probabilities of small firms are equally cyclical or even more cyclical than the default probabilities of large firms. These results hold using a multiplicative Cox model as well as an additive Aalen model with time-varying coefficients
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