33 research outputs found

    Signal propagation modelling for vehicle-to-infrastructure communication under the influence of metal obstruction

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    Connected car has become one of emerging technology in the automotive industries today. This development preludes a rise in vehicular communication studies that primarily targets radio channel modelling on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication mode. Considering vehicular obstruction, vast channel propagation studies have focused more on V2V mode while others consider the typical urban scenarios consisting of high traffic volumes of moving vehicles. Due to challenging propagation mechanisms and high complexity in such areas, radio propagation models applied in simulators assume an obstacle-free environment rather than considering the least effect imposed by metal obstruction on communication signal. Besides, there are limited studies pertaining to metal obstruction that considers several under-explored environments such as actual parking lots, junctions and other road infrastructure support. As such, this paper demonstrates signal attenuation analysis caused by the presence of metal objects in low density over obstacle-free environment on actual parking lot via V2I mode. Two scenarios such as LOS and NLOS conditions consisting of obstacle-free, cars and buses as static metal objects are evaluated. The aim of this research is to characterize signal strength caused by metal blockage on radio wave propagation predicated on the presence of vehicles as a subject of obstruction in comparison to obstacle-free vehicular environment. The validity of data is shown through received signal strength indicator (RSSI) and approximation analysis (RMSE) to demonstrate the efficiency of obtained measurements. The results demonstrated that Log-normal shadowing model yields the best fit to low-density metal obstruction scenario with smallest RMSE of 4.78 under bus obstruction whereas 5.72 under car obstruction

    Fuzzy Membership Functions Tuning For Speed Controller Of Induction Motor Drive: Performance Improvement.

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    Fuzzy logic controller (FLC) has gained high interest in the field of speed control of machine drives in both academic and industrial communities. This is due to the features of FLC of handling non-linearity and variations. FLC system consists of three main elements: scaling factors (SFs), membership functions (MFs), and rule-base. Fuzzy MFs can be designed with different types and sizes. For induction motor (IM) speed control, (3x3), (5x5) and (7x7) MFs are the most used MFs sizes, and normally designed based on symmetrical distribution. However, changing the width and peak position of MFs design enhance the performance. In this paper, tuning of MFs of FLC speed control of IM drives is considered. Considering (3x3), (5x5) and (7x7) MFs sizes, the widths and peak positions of these MFs are asymmetrically distributed to improve the performance of IM drive. Based on these MFs sizes, the widths and peak positions are moved toward the origin (zero), negative and positive side that produces a controller less sensitive to the small error variations. Based on simulation and performance evaluations, improvement of 5% in settling time (Ts), 0.5% in rise time and 20% of steady-state improvement achieved with the tuned MFs compared to original MFs

    Global, regional, and national age-sex-specific burden of diarrhoeal diseases, their risk factors, and aetiologies, 1990–2021, for 204 countries and territories: a systematic analysis for the Global Burden of Disease Study 2021

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    Fuzzy membership functions tuning for speed controller of induction motor drive: performance improvement

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    &lt;p&gt;Fuzzy &lt;span&gt;logic controller (FLC) has gained high interest in the field of speed control of machine drives in both academic and industrial communities. This is due to the features of FLC of handling non-linearity and variations. FLC system consists of three main elements: scaling factors (SFs), membership functions (MFs), and rule-base. Fuzzy MFs can be designed with different types and sizes. For induction motor (IM) speed control, (3x3), (5x5) and (7x7) MFs are the most used MFs sizes, and normally designed based on symmetrical distribution. However, changing the width and peak position of MFs design enhance the performance. In this paper, tuning of MFs of FLC speed control of IM drives is considered. Considering (3x3), (5x5) and (7x7) MFs sizes, the widths and peak positions of these MFs are asymmetrically distributed to improve the performance of IM drive. Based on these MFs sizes, the widths and peak positions are moved toward the origin (zero), negative and positive side that produces a controller less sensitive to the small error variations. Based on simulation and performance evaluations, improvement of 5% in settling time (Ts), 0.5% in rise time and 20% of steady-state improvement achieved with the tuned MFs compared to original &lt;/span&gt;MFs.&lt;/p&gt;</jats:p

    Patient and clinician opinions of patient reported outcome measures (PROMs) in the management of patients with rare diseases: a qualitative study.

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    BACKGROUND Rare diseases may be life-threatening or chronically debilitating conditions. Patient care needs are often complex and challenging to coordinate and deliver effectively. Rare diseases and their clinical management may therefore substantially impact on patients' health-related quality of life (HRQOL). The use of patient-reported outcome measures (PROMs) may complement clinical assessments by elucidating patients' perspectives on their health status and care priorities. This study explored the opinions of patients and clinicians on the use of PROMs in the management of patients with rare diseases in routine clinical practice. METHODS A total of 15 semi-structured one-to-one interviews were conducted with four patients with primary sclerosing cholangitis (PSC); five renal transplant recipients; and six PSC doctors from University Hospitals Birmingham (UHB) NHS Foundation Trust. A focus group session was also conducted with 10 clinical staff members (doctors, nurses and other allied health professionals from UHB). The suitability and acceptability of the Chronic Liver Disease Questionnaire (CLDQ) and the Short Form 12 (SF12) were assessed by patients with PSC and their doctors while the Paediatric quality of life inventory Transplant Module (PedsQL-TM) and the EuroQoL-5 dimensions (EQ. 5D) were evaluated by the renal transplant recipients and their doctors. The discussions were audio recorded and transcribed verbatim. Coding of the transcripts was done using the Nvivo 11 Plus software. Thematic analysis was conducted to identify the main themes and subthemes. RESULTS Four themes were identified, namely: (i) potential benefits of PROMs in the management of rare diseases; (ii) views on selected questionnaires; (iii) practical considerations for implementation; and (iv) potential facilitators and barriers of implementation. Patients and clinicians suggested that the use of ePROMs may facilitate patient-centred care by promoting patient-clinician communication, highlighting aspects of HRQOL that are important to patients and encouraging patient involvement in their care. They also felt that the disease-specific CLDQ and PedsQL-TM were more relevant than the generic SF12 and EQ-5D. CONCLUSIONS Patients with rare diseases often experience impaired HRQOL. The use of an ePROM system may enhance the routine management of patients with rare diseases
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