39 research outputs found

    Performance Analysis of Discrete Wavelet Multitone Transceiver for Narrowband PLC in Smart Grid

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    Smart Grid is an abstract idea, which involves the utilization of powerlines for sensing, measurement, control and communication for efficient utilization and distribution of energy, as well as automation of meter reading, load management and capillary control of Green Energy resources connected to the grid. Powerline Communication (PLC) has assumed a new role in the Smart Grid scenario, adopting the narrowband PLC (NB-PLC) for a low cost and low data rate communication for applications such as, automatic meter reading, dynamic management of load, etc. In this paper, we have proposed and simulated a discrete wavelet multitone (DWMT) transceiver in the presence of impulse noise for the NB-PLC channel applications in Smart Grid. The simulation results show that a DWMT transceiver outperforms a DFT-DMT with reference to the bit error rate (BER) performance

    Mini Clinical Evaluation Exercise (Mini-CEX): An overview

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    Over the last two decades, medical education has changed its role significantly to move from the traditional curriculum to the outcome based education. This is done after deciding the competencies to be achieved by the students more clearly1. The Institute for International Medical Education (IIME) has clearly focused the minimum essential core competencies that a medical graduate must possess including the clinical skills, communication skills, professional values, attitudes and behaviors1.&nbsp

    Evaluation of multiple choice and short essay question items in basic medical sciences

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    OBJECTIVES: To evaluate Multiple Choice and Short Essay Question items in Basic Medical Sciences by determining item writing flaws (IWFs) of MCQs along with cognitive level of each item in both methods. METHODS: This analytical study evaluated the quality of the assessment tools used for the first batch in a newly established medical college in Karachi, Pakistan. First and sixth module assessment tools in Biochemistry during 2009-2010 were analyzed. Cognitive level of MCQs and SEQs, were noted and MCQ item writing flaws were also evaluated. RESULTS: A total of 36 SEQs and 150 MCQs of four items were analyzed. The cognitive level of 83.33% of SEQs was at recall level while remaining 16.67% were assessing interpretation of data. Seventy six percent of the MCQs were at recall level while remaining 24% were at the interpretation. Regarding IWFs, 69 IWFs were found in 150 MCQs. The commonest among them were implausible distracters (30.43%), unfocused stem (27.54%) and unnecessary information in the stem (24.64%). CONCLUSION: There is a need to review the quality including the content of assessment tools. A structured faculty development program is recommended for developing improved assessment tools that align with learning outcomes and measure competency of medical students

    Volatilidade do mercado de açÔes do Paquistão: uma comparação de modelos do tipo Garch com cinco

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    This study conducts empirical analyses modeling the volatility of Pakistani stock market over the period of 1st January 2008 to 30th June 2018 via different GARCH type Model; Symmetric (GARCH & GARCH-M) and Asymmetric (EGARCH & TGARCH) with five different Distribution Techniques such as Normal Distribution (Norm), Student’s t Distribution (Std.), Generalized Error Distribution (GED), Student’s t Distribution with fix the degree of freedom (Std. with fix DOF) and Generalized Error Distribution with fix parameters (GED with fix parameters). The results are shown in GARCH (1, 1) lagged conditional variance and squared disturbance which effects conditional variance is significant in all distribution. GARCH-M (1, 1) depicts a positive significant at 1% results in Std. and GED which indicates the existence of risk premium and insignificant in rest of the distribution on. EGARCH and TGARCH both are found to leverage effect significant at 1% level. In determining the accuracy and adequacy of forecasting density and choice of volatility model the results on simulated data indicates choice of conditional distribution appear as a more dominant factor. EGARCH model with Student’s t the distribution technique is delivered satisfactory results as compare to other models which censored by statistical tools of maximum Log Likelihood, minimum AIC, and SIC. The previous study of Pakistani Stock Market is limited to GARCH family models with one or two distributions. This study covers the limitations and also contributes existing literature in this regard. This research is considered important for investors, policymakers, and researchers.Este estudio realiza anĂĄlisis empĂ­ricos que modelan la volatilidad del mercado de valores pakistanĂ­ durante el perĂ­odo del 1 de enero de 2008 al 30 de junio de 2018 a travĂ©s de diferentes modelos de tipo GARCH; SimĂ©trico (GARCH & GARCH-M) y Asymmetric (EGARCH & TGARCH) con cinco tĂ©cnicas de distribuciĂłn diferentes, como la distribuciĂłn normal (Norm), la distribuciĂłn t de Student (Std.), La distribuciĂłn de errores generalizada (GED), la distribuciĂłn t de Student con la correcciĂłn del grado de libertad (Std. con correcciĂłn DOF) y DistribuciĂłn de errores generalizada con parĂĄmetros de correcciĂłn (GED con parĂĄmetros de correcciĂłn). Los resultados se muestran en GARCH (1, 1) varianza condicional retrasada y perturbaciĂłn al cuadrado, lo que afecta a la varianza condicional es significativo en toda la distribuciĂłn. GARCH-M (1, 1) muestra un resultado positivo significativo al 1% en la norma. y GED, que indica la existencia de prima de riesgo e insignificante en el resto de la distribuciĂłn en. Tanto EGARCH como TGARCH tienen un efecto de apalancamiento significativo al nivel del 1%. Al determinar la precisiĂłn y la adecuaciĂłn de la densidad de pronĂłstico y la elecciĂłn del modelo de volatilidad, los resultados en datos simulados indican que la elecciĂłn de la distribuciĂłn condicional aparece como un factor mĂĄs dominante. El modelo EGARCH con la tĂ©cnica de distribuciĂłn de Student se entrega con resultados satisfactorios en comparaciĂłn con otros modelos que estĂĄn censurados por las herramientas estadĂ­sticas de mĂĄxima probabilidad de registro, mĂ­nimo AIC y SIC. El estudio anterior de la Bolsa de Valores de PakistĂĄn se limita a los modelos de la familia GARCH con una o dos distribuciones. Este estudio cubre las limitaciones y tambiĂ©n aporta la literatura existente en este sentido. Esta investigaciĂłn se considera importante para los inversores, los responsables polĂ­ticos y los investigadores.Este estudo realiza anĂĄlises empĂ­ricas modelando a volatilidade do mercado de açÔes paquistanĂȘs no perĂ­odo de 1Âș de janeiro de 2008 a 30 de junho de 2018 atravĂ©s de diferentes modelos do tipo GARCH; SimĂ©trico (GARCH & GARCH-M) e AssimĂ©trico (EGARCH & TGARCH) com cinco diferentes TĂ©cnicas de Distribuição, como Distribuição Normal (Norm), Distribuição t de Student (PadrĂŁo), Distribuição de Erro Generalizada (GED), Distribuição t de Student com correção do grau de liberdade (Std. com correção de DOF) e distribuição de erros generalizada com parĂąmetros de correção (GED com parĂąmetros de correção). Os resultados sĂŁo apresentados na variĂąncia condicional defasada GARCH (1, 1) e na perturbação quadrada que afeta a variĂąncia condicional em todas as distribuiçÔes. GARCH-M (1, 1) representa um significante positivo com resultados de 1% em Std. e GED que indica a existĂȘncia de prĂȘmio de risco e insignificante em resto da distribuição em. EGARCH e TGARCH ambos sĂŁo encontrados para alavancar o efeito significativo ao nĂ­vel de 1%. Ao determinar a precisĂŁo e a adequação da densidade de previsĂŁo e a escolha do modelo de volatilidade, os resultados em dados simulados indicam que a escolha da distribuição condicional aparece como um fator mais dominante. O modelo EGARCH com Student t a tĂ©cnica de distribuição apresenta resultados satisfatĂłrios quando comparado a outros modelos que foram censurados por ferramentas estatĂ­sticas de mĂĄxima Likelihood, mĂ­nima AIC e SIC. O estudo anterior do mercado de açÔes paquistanĂȘs Ă© limitado a modelos de famĂ­lia GARCH com uma ou duas distribuiçÔes. Este estudo cobre as limitaçÔes e tambĂ©m contribui com a literatura existente a esse respeito. Esta pesquisa Ă© considerada importante para investidores, formuladores de polĂ­ticas e pesquisadores

    Optimization of non-orthogonal multiple access based visible light communication systems

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    In visible light communication (VLC), the data is transmitted by modulating the light emitting diode (LED). The data-rate is throttled by the narrow modulation bandwidth of LEDs, which becomes a barrier for attaining high transmission rates. Non-orthogonal multiple access (NOMA) is a new scheme envisioned to improve the system capacity. In addition to multiple access schemes, optimization techniques are applied to further improve the data rate. In this letter, convex optimization is applied to NOMA-based VLC system for downlink. The proposed optimization system is analyzed in terms of the bit error rate (BER) and the sum-rate

    A novel automated demand response control using fuzzy logic for islanded battery‐operated rural microgrids

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    Islanded rural microgrid require continuous resource monitoring. Demand response schemes have been phenomenal in managing loads. However, urban demand response schemes are well equipped with market prices and peak time penalties to control deferrable loads. In rural microrids, regular loads such as fans, lights and water pumps are normally used that do not fall under category of deferrable loads. In addition, full liberty of utilizing regular load at any time, lack of awareness and no information of storage reserves make task of load management more complex. In this research fully automated two layered demand response scheme is designed for regular operating loads. The first layer control is load mode control. The mode of operation is decided on the state of charge (SoC) of battery. In second layer, fuzzy controller is designed on the consumer's routines, SoC and ambient temperature as membership function. Results are assessed in terms of consumers comfort and availablity of SoC. The load operation in automated demand response remained indentical to actual rutine operation as per consumer's desire with 5 to 7% deviation. In all modes of operation SoC levels remained 15% higher and heavy load operated 13.5% more compare to relevant study

    Checklist of family Poaceae in Lahaul and Spiti district (Cold Desert), Himachal Pradesh, India

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    The present study provides an overview of the diversity and distribution of grass species in Lahaul- Spiti district (cold desert) situated in the Trans-Himalayan region i.e. Himachal Pradesh, India. From the study area 141 taxa (138 species and 3 subspecies) belonging to 14 tribes were recorded. The largest tribe was Festuceae followed by Agrostideae having 48 and 20 species, respectively. Two species Poa koelzii and P. Lahaulensis are endemic to Lahaul- Spiti. Puccinellia kashmiriana is rare as per IUCN status. The present study on the grass floral wealth of Lahaul-Spiti provides an important baseline data on grasses for further quantitative and qualitative investigations like their nutritive values, crop improvement programmes and shall also help in the identification of priority conservation areas in the region

    Share of afghanistan populace in hepatitis B and hepatitis C infection's pool: is it worthwhile?

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    There is a notable dearth of data about Hepatitis B Virus (HBV) and Hepatitis C Virus(HCV) prevalence in Afghanistan. Awareness program and research capacity in the field of hepatitis are very limited in Afghanistan. Number of vulnerabilities and patterns of risk behaviors signal the need to take action now

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

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    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
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