Parameter Estimation of Power Function Distribution with TL-moments

Accurate estimation of parameters of a probability distribution is of immense importance in statistics. Biased and imprecise estimation of parameters can lead to erroneous results. Our focus is to estimate the parameter of Power function distribution accurately because this density is now widely used for modelling various types of data.  In this study, L-moments, TL-moments, LL-moments and LH-moments of Power function distribution are derived. In addition, the coefficient of variation, skewness and kurtosis are obtained by method of moments, L-moments and TL-moments. Parameters of the density are estimated using linear moments and compared with method of moments and MLE on the basis of bias, root mean square error and coefficients through simulation study. L-moments proved to be superior for the parameter estimation and this conclusion is equally true for different parametric values and sample size.La distribución de función de potencias es ampliamente usada. Dada su importancia, es necesario estimar sus parámetros de manera precisa. En este artículo, los momentos TL de la distribución de función de potencias son derivados así como sus casos especiales tales como los momentos L, LL y LH. Los coeficientes de variación, sesgo y curtosis son obtenidos a partir de los momentos L y TL. Los parámetros desconocidos son estimados y los momentos lineales son comparados con el método de momentos y estimadores máximo verosímiles en la base del sesgo, raíz del error cuadrático medio a través de un estudio de simulación. Los momentos L permiten obtener estimaciones más precisas y esta conclusión es verdad para diferentes valores paramétricos y tamaño de muestra

EMMON: a system architecture for large- scale, dense and real-time WSNs

In spite of the significant amount of scientific work in Wireless Sensor Networks (WSNs), there is a clear lack of effective, feasible and usable WSN system architectures that address both functional and non-functional requirements in an integrated fashion. This poster abstract outlines the EMMON system architecture for large-scale, dense, real-time embedded monitoring. EMMON relies on a hierarchical network architecture together with integrated middleware and command&control mechanisms. It has been designed to use standard commercially– available technologies, while maintaining as much flexibility as possible to meet specific applications’ requirements. The EMMON WSN architecture has been validated through extensive simulation and experimental evaluation, including through a 300+ node test-bed, the largest WSN test-bed in Europe to dat

The Thermal Performance Analysis of an Al2O3-Water Nanofluid Flow in a Composite Microchannel

Partial filling of porous medium insert in a channel alleviates the tremendous pressure drop associated with a porous medium saturated channel, and enhances heat transfer at an optimum fraction of porous medium filling. This study pioneered an investigation into the viscous dissipative forced convective heat transfer in a parallel-plate channel, partially occupied with a porous medium at the core, under local thermal non-equilibrium condition. Solving the thermal energy equation along the Darcy–Brinkman equation, new exact temperature fields and Nusselt number are presented under symmetrical isoflux thermal boundary condition. Noteworthy is the heat flux bifurcation at the interface between the clear fluid and porous medium driven by viscous dissipation, in cases where the combined hydrodynamic resistance to fluid flow and thermal resistance to fluid conduction is considerable in low Darcy number porous medium insert. However, viscous dissipation does not affect the qualitative variation of the Nusselt number with the fraction of porous medium filling. By using Al2O3-Water nanofluid as the working fluid in a uniformly heated microchannel, partially filled with an optimum volume fraction of porous medium, the heat transfer coefficient improves as compared to utilizing water. The accompanied viscous dissipation however has a more adverse impact on the heat transfer coefficient of nanofluids with an increasing Reynolds number

Airway fires during surgery: Management and prevention

Airway fires pose a serious risk to surgical patients. Fires during surgery have been reported for many years with flammable anesthetic agents being the main culprits in the past. Association of airway fires with laser surgery is well-recognized, but there are reports of endotracheal tube fires ignited by electrocautery during pharyngeal surgery or tracheostomy or both. This uncommon complication has potentially grave consequences. While airway fires are relatively uncommon occurrences, they are very serious and can often be fatal. Success in preventing such events requires a thorough understanding of the components leading to a fire (fuel, oxidizer, and ignition source), as well as good communication between all members present to appropriately manage the fire and ensure patient safety. We present a case of fire in the airway during routine adenotonsillectomy. We will review the causes, preventive measures, and brief management for airway fires

Viscous Dissipative Forced Convection in a Channel Partially Filled with Porous Medium

Partial filling of a porous medium in a channel of a certain configuration attracts attention, as it tends to enhance convective heat transfer while reducing pressure drop remarkably, as compared to a fully filled porous channel. In this study, forced convection heat transfer in a channel partially filled with a porous medium adjoining the wall is investigated analytically, where viscous dissipation is accounted for under local thermal nonequilibrium (LTNE) conditions. Because of viscous dissipation, the newly derived exact temperature profile reveals a magnified temperature difference between the fluid and solid phases and a more intense heat-flux bifurcation in cases where the heat transfer in the porous medium is dominated by solid conduction. The Nusselt-number depiction as a function of Darcy number at a fixed porous medium thickness reveals the existence of a Darcy number that maximizes the Nusselt number and highlights the competition between the convection heat transfer and heat source in the form of viscous dissipation, as Darcy number increases. The strong dependency of the Nusselt number on Brinkman number, in cases where the thermal resistance to fluid conduction is dominant, demonstrates the importance of incorporating viscous dissipation effects to the temperature field under LTNE condition

Poster: EMMON: a WSN system architecture and toolset for large-scale and dense real-time embedded monitoring

Wireless sensor networks (WSNs) have attracted growing interest in the last decade as an infrastructure to support a diversity of ubiquitous computing and cyber-physical systems. However, most research work has focused on protocols or on specific applications. As a result, there remains a clear lack of effective and usable WSN system architectures that address both functional and non-functional requirements in an integrated fashion. This poster outlines the EMMON system architecture for large-scale, dense, real-time embedded monitoring. It provides a hierarchical communication architecture together with integrated middleware and command and control software. It has been designed to maintain as much as flexibility as possible while meeting specific applications requirements. EMMON has been validated through extensive analytical, simulation and experimental evaluations, including through a 300+ nodes test-bed the largest single-site WSN test-bed in Europe

Post-transplant infections: single center experience from the developing world

SummaryObjectiveTo describe our experience of post-transplant infections in allogeneic stem cell transplants at the Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan.MethodsFrom July 2001 to September 2006, patients with malignant and non-malignant hematological disorders having human leukocyte antigen (HLA)-matched sibling donors were selected for transplant. Pre-transplant infection surveillance was carried out, and strict prophylaxis against infection was observed. After admission to the hospital, patients were kept in protective isolation rooms, equipped with a HEPA filter positive-pressure laminar airflow ventilation system. Bone marrow and/or peripheral blood stem cells were used as the stem cell source. Cyclosporin and prednisolone were used as prophylaxis against graft-versus-host disease (GVHD). The engraftment was monitored with cytogenetic/molecular analysis and change of blood group. Survival was calculated from the date of transplant to death or last follow-up.ResultsOne hundred and fifty-four patients received allogeneic stem cell transplants from HLA-matched siblings for various hematological disorders at the Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan between July 2001 and September 2006. Indications for transplant included aplastic anemia (n=66), β-thalassemia major (n=40), chronic myeloid leukemia (n=33), acute leukemia (n=8), and miscellaneous disorders (n=7). One hundred and twenty patients were male and 34 were female. The median age of the patient cohort was 14 years (range 114−54 years). One hundred and thirty-six patients and 135 donors were cytomegalovirus (CMV) IgG-positive. One hundred and forty patients (90.9%) developed febrile episodes in different phases of post-transplant recovery. Infective organisms were isolated in 150 microbiological culture specimens out of 651 specimens from different sites of infections (23.0% culture positivity). Post-transplant infections were confirmed in 120 patients (77.9%) on the basis of clinical assessment and microbiological, virological, and histopathological examination. Mortality related to infections was 13.0%. Fatal infections included CMV disease (100% mortality, 6/6), disseminated aspergillosis (66.7% mortality, 4/6), pseudomonas septicemia (42.9% mortality, 9/21), and tuberculosis (25% mortality, 1/4).ConclusionsMore than 90% of our patients developed febrile episodes with relatively low culture yield. The majority of infections were treated effectively, however CMV, aspergillosis, and pseudomonas infections remained problematic with high mortality