9,830 research outputs found

    Analyzing Energy-efficiency and Route-selection of Multi-level Hierarchal Routing Protocols in WSNs

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    The advent and development in the field of Wireless Sensor Networks (WSNs) in recent years has seen the growth of extremely small and low-cost sensors that possess sensing, signal processing and wireless communication capabilities. These sensors can be expended at a much lower cost and are capable of detecting conditions such as temperature, sound, security or any other system. A good protocol design should be able to scale well both in energy heterogeneous and homogeneous environment, meet the demands of different application scenarios and guarantee reliability. On this basis, we have compared six different protocols of different scenarios which are presenting their own schemes of energy minimizing, clustering and route selection in order to have more effective communication. This research is motivated to have an insight that which of the under consideration protocols suit well in which application and can be a guide-line for the design of a more robust and efficient protocol. MATLAB simulations are performed to analyze and compare the performance of LEACH, multi-level hierarchal LEACH and multihop LEACH.Comment: NGWMN with 7th IEEE Inter- national Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA 2012), Victoria, Canada, 201

    Pleomorphic liposarcoma in a ten year old child

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    The future of big data in facilities management : opportunities and challenges

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    Purpose: This paper explores the current condition of the Big Data concept with its related barriers, drivers, opportunities and perceptions in the AEC industry with an emphasis on Facilities Management (FM). Design/methodology/approach: Following a comprehensive literature review, the Big Data concept was investigated through two scoping workshops with industry experts and academics. Findings: The value in data analytics and Big Data is perceived by the industry; yet the industry needs guidance and leadership. Also, the industry recognises the imbalance between data capturing and data analytics. Large IT vendors’ developing AEC industry focused analytics solutions and better interoperability among different vendors are needed. The general concerns for Big Data analytics mostly apply to the AEC industry as well. Additionally however, the industry suffers from a structural fragmentation for data integration with many small-sized companies operating in its supply chains. This paper also identifies a number of drivers, challenges and way-forwards that calls for future actions for Big Data in FM in the AEC industry. Originality/value: The nature of data in the business world has dramatically changed over the past 20 years. This phenomenon is often broadly dubbed as “Big Data” with its distinctive characteristics, opportunities and challenges. Some industries have already started to effectively exploit “Big Data” in their business operations. However, despite many perceived benefits, the AEC industry has been slow in discussing and adopting the Big Data concept. Empirical research efforts investigating Big Data for the AEC industry are also scarce. This paper aims at outlining the benefits, challenges and future directions (what to do) for Big Data in the AEC industry with a FM focus

    Cystic artery pseudo-aneurysm: a complication of xanthogranulomatous cholecystitis

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    A 54-year-old man presented for radiology with pain and a feeling of fullness in the upper abdomen and an epigastric mass. Ultrasound revealed a large cystic mass with internal echoes, lying posterior and inferior to left lobe of the liver. The gallbladder was thick-walled and contracted, and contained a calculus and echogenic sludge. A cystic structure that produced swirling flow signals on colour Doppler was demonstrated within the gallbladder. The CT scan showed a thickened gallbladder with adjacent inflammation and a 2-cm pseudo-aneurysm in its wall. High-density material was present in the gallbladder lumen, in the extra-hepatic bile ducts and around the gastrohepatic ligament. A thick haemorrhagic pus, from which Escherichia coli was cultured, was drained from the gastrohepatic collection. An elective coeliac angiogram demonstrated a solitary pseudo-aneurysm of the medial branch of the cystic artery. Selective catheterisation of this artery with a micro-catheter enabled complete exclusion of the pseudo-aneurysm by a single micro-coil. Histological examination of the gallbladder, which was ultimately removed at open cholecystectomy, demonstrated xanthogranulomatous cholecystitis

    Monitoring and Controlling Power using Zigbee Communications

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    Smart grid is a modified form of electrical grid where generation, transmission, distribution and customers are not only connected electrically but also through strong communication network with each other as well as with market, operation and service provider. For achieving good communication link among them, it is very necessary to find suitable protocol. In this paper, we discuss different hardware techniques for power monitoring, power management and remote power controlling at home and transmission side and also discuss the suitability of Zigbee for required communication link. Zigbee has major role in monitoring and direct load controlling for efficient power utilization. It covers enough area needed for communication and it works on low data rate of 20Kbps to 250Kbps with minimum power consumption. This paper describes the user friendly control home appliances, power on/off through the internet, PDA using Graphical User Interface (GUI) and through GSM cellular mobile phone.Comment: 5th International Workshop on NGWMN with 7th IEEE International Conference on BWCCA 2012, Victoria, Canada, 201

    Outputs and Growth of Primary Care Databases in the United Kingdom: Bibliometric Analysis.

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    BACKGROUND: Electronic health database (EHD) data is increasingly used by researchers. The major United Kingdom EHDs are the 'Clinical Practice Research Datalink' (CPRD), 'The Health Improvement Network' (THIN) and 'QResearch'. Over time, outputs from these databases have increased, but have not been evaluated. OBJECTIVE: This study compares research outputs from CPRD, THIN and QResearch assessing growth and publication outputs over a 10-year period (2004-2013). CPRD was also reviewed separately over 20 years as a case study. METHODS:  Publications from CPRD and QResearch were extracted using the Science Citation Index (SCI) of the Thomson Scientific Institute for Scientific Information (Web of Science). THIN data was obtained from University College London and validated in Web of Science. All databases were analysed for growth in publications, the speciality areas and the journals in which their data have been published. RESULTS: These databases collectively produced 1,296 publications over a ten-year period, with CPRD representing 63.6% (n=825 papers), THIN 30.4% (n=394) and QResearch 5.9% (n=77). Pharmacoepidemiology and General Medicine were the most common specialities featured. Over the 9-year period (2004-2013), publications for THIN and QResearch have slowly increased over time, whereas CPRD publications have increased substantially in last 4 years with almost 75% of CPRD publications published in the past 9 years. CONCLUSION: These databases are enhancing scientific research and are growing yearly, however display variability in their growth. They could become more powerful research tools if the National Health Service and general practitioners can provide accurate and comprehensive data for inclusion in these databases

    Delta-Function Potential with a Complex Coupling

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    We explore the Hamiltonian operator H=-d^2/dx^2 + z \delta(x) where x is real, \delta(x) is the Dirac delta function, and z is an arbitrary complex coupling constant. For a purely imaginary z, H has a (real) spectral singularity at E=-z^2/4. For \Re(z)<0, H has an eigenvalue at E=-z^2/4. For the case that \Re(z)>0, H has a real, positive, continuous spectrum that is free from spectral singularities. For this latter case, we construct an associated biorthonormal system and use it to perform a perturbative calculation of a positive-definite inner product that renders H self-adjoint. This allows us to address the intriguing question of the nonlocal aspects of the equivalent Hermitian Hamiltonian for the system. In particular, we compute the energy expectation values for various Gaussian wave packets to show that the non-Hermiticity effect diminishes rapidly outside an effective interaction region.Comment: Published version, 14 pages, 2 figure
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