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Performance Close (performance + close)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

An analytical approach to the performance evaluation of the balanced gamma switch under multicast traffic,

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2007
Cheng Li
Abstract This paper presents the performance evaluation of a new cell-based multicast switch for broadband communications. Using distributed control and a modular design, the balanced gamma (BG) switch features high performance for unicast, multicast and combined traffic under both random and bursty conditions. Although it has buffers on input and output ports, the multicast BG switch follows predominantly an output-buffered architecture. The performance is evaluated under uniform and non-uniform traffic conditions in terms of cell loss ratio and cell delay. An analytical model is presented to analyse the performance of the multicast BG switch under multicast random traffic and used to verify simulation results. The delay performance under multicast bursty traffic is compared with those from an ideal pure output-buffered multicast switch to demonstrate how close its performance is to that of the ideal but impractical switch. Performance comparisons with other published switches are also studied through simulation for non-uniform and bursty traffic. It is shown that the multicast BG switch achieves a performance close to that of the ideal switch while keeping hardware complexity reasonable. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Fundamental study on biomass-fuelled ceramic fuel cell

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2002
B. Zhu
Abstract Recent development in the advanced intermediate temperature (400 to 700°C) ceramic fuel cell (CFC) research brings up feasibility and new opportunity to develop innovative biomass-fuelled CFC technology. This work focuses on fundamentals of the biomass-fuelled CFCs based on available biofuel resources through thermochemical conversion technologies. Both real producer gas from biomass gasification and imitative compounded gas were used as the fuel to operate the CFCs in the biomass CFC testing station. The composition of the fuel gas was varied in a wide range of practices of the present conversion technology both in KTH and Shandong Institute of Technology (SDIT). CFC performances were achieved between 100 and 700 mW cm,2 at 600,800°C corresponding to various gas compositions. A high performance close to 400 mW cm,2 was obtained at 600°C for the gas with the composition of H2 (50 per cent)+CO (15 per cent)+CO2 (15 per cent)+N2 (20 per cent) and more than 600 mW cm,2 for the H2 (55 per cent)+CO (28 per cent)+CO2 (17 per cent) at 700°C. This paper presents the experimental results and discusses the fundamentals and future potentiality on the biomass fuelled CFCs. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Variation in GH and IGF-I assays limits the applicability of international consensus criteria to local practice

CLINICAL ENDOCRINOLOGY, Issue 1 2007
A. Pokrajac
Summary Background, There is increasing reliance on consensus criteria for decision making. Recent criteria state that acromegaly is excluded by a nadir GH during an oral glucose tolerance test (OGTT) of < 1 µg/l and a normal level of IGF-I. Objective, To study GH and IGF-I assay performance close to cut-off values for active acromegaly. Design and methods, Two serum samples known to give borderline results were sent to all centres participating in the UK National External Quality Assessment Service (NEQAS). Sample A was assigned to be a nadir during an OGTT and sent for GH assessment to 104 centres. Sample B, with a clinical scenario, was sent to 23 centres that measure IGF-I, and these centres were asked to measure IGF-I, interpret the result and provide the source of their reference ranges (RRs). Results, For sample A, the median GH was 2·6 mU/l (range 1·04,3·5 mU/l). Applying a conversion factor (CF) of 2·0 (1 µg/l = 2 mU/l), the most negatively biased method classified 10% of the values consistent with acromegaly, while the most positively biased method classified all values as consistent with the diagnosis. Applying a CF of 3·0 (1 µg/l = 3 mU/l), only 11% of results were consistent with acromegaly. For sample B, the median IGF-I was 50·8 nmol/l (range 24·3,60·9 nmol/l). All centres used age-related RRs. There was a 50% variation in the upper limit of the RRs between centres. Overall, 30% of the IGF-I results were against the diagnosis. There was little agreement in the RRs quoted by centres using the same method. Conclusion, Variability in assay performance, coupled with use of inappropriate CFs and RRs, undermines the applicability of international consensus criteria to local practice. [source]

A CASE-BASED DECISION SUPPORT SYSTEM FOR INDIVIDUAL STRESS DIAGNOSIS USING FUZZY SIMILARITY MATCHING

COMPUTATIONAL INTELLIGENCE, Issue 3 2009
Shahina Begum
Stress diagnosis based on finger temperature (FT) signals is receiving increasing interest in the psycho-physiological domain. However, in practice, it is difficult and tedious for a clinician and particularly less experienced clinicians to understand, interpret, and analyze complex, lengthy sequential measurements to make a diagnosis and treatment plan. The paper presents a case-based decision support system to assist clinicians in performing such tasks. Case-based reasoning (CBR) is applied as the main methodology to facilitate experience reuse and decision explanation by retrieving previous similar temperature profiles. Further fuzzy techniques are also employed and incorporated into the CBR system to handle vagueness, uncertainty inherently existing in clinicians reasoning as well as imprecision of feature values. Thirty-nine time series from 24 patients have been used to evaluate the approach (matching algorithms) and an expert has ranked and estimated similarity. On average goodness-of-fit for the fuzzy matching algorithm is 90% in ranking and 81% in similarity estimation that shows a level of performance close to an experienced expert. Therefore, we have suggested that a fuzzy matching algorithm in combination with CBR is a valuable approach in domains, where the fuzzy matching model similarity and case preference is consistent with the views of domain expert. This combination is also valuable, where domain experts are aware that the crisp values they use have a possibility distribution that can be estimated by the expert and is used when experienced experts reason about similarity. This is the case in the psycho-physiological domain and experienced experts can estimate this distribution of feature values and use them in their reasoning and explanation process. [source]