SLA-Oriented Resource Provisioning for Cloud Computing: Challenges, Architecture, and Solutions

Cloud computing systems promise to offer subscription-oriented, enterprise-quality computing services to users worldwide. With the increased demand for delivering services to a large number of users, they need to offer differentiated services to users and meet their quality expectations. Existing resource management systems in data centers are yet to support Service Level Agreement (SLA)-oriented resource allocation, and thus need to be enhanced to realize cloud computing and utility computing. In addition, no work has been done to collectively incorporate customer-driven service management, computational risk management, and autonomic resource management into a market-based resource management system to target the rapidly changing enterprise requirements of Cloud computing. This paper presents vision, challenges, and architectural elements of SLA-oriented resource management. The proposed architecture supports integration of marketbased provisioning policies and virtualisation technologies for flexible allocation of resources to applications. The performance results obtained from our working prototype system shows the feasibility and effectiveness of SLA-based resource provisioning in Clouds.Comment: 10 pages, 7 figures, Conference Keynote Paper: 2011 IEEE International Conference on Cloud and Service Computing (CSC 2011, IEEE Press, USA), Hong Kong, China, December 12-14, 201

Obstetric and neonatal outcomes of the pregnancies complicated with thrombocytopenia

Background: Thrombocytopenia is second most common hematological abnormality in pregnancy after anemia (Incidence 8-10%). The aim of this study is to observe the obstetric and neonatal outcomes of pregnancies complicated with thrombocytopenia and to compare its maternal and fetal outcomes.Methods: The prospective observational study was conducted at tertiary care institute over period of one and half year and 100 cases of thrombocytopenia in present pregnancy were included after fulfilling inclusion and exclusion criteria and obtaining written informed valid consent. Complete history, physical examination and relevant investigations of the patient were documented. Patients were followed up to delivery and outcomes (obstetric, maternal, fetal, neonatal) were studied. The data obtained for all the patients was analyzed with SPSS (SPSS Inc, Chicago) software packages. Statistical comparisons were performed with Pearson’s Chi- square where appropriate with p-value of 37 weeks of gestation. Most (53%) had moderate thrombocytopenia. Incidence of maternal complications was statically significant (P-value 0.038) with most common complication being caesarian section site oozing (9%) followed by placental abruption (4%). There was no statistical significance in degree of thrombocytopenia and need for blood and blood product transfusion (P-value 0.67). Only (2%) neonates of thrombocytopenic mothers had thrombocytopenia and both required treatment.Conclusions: Most common cause of thrombocytopenia in pregnancy was gestational thrombocytopenia with uneventful pregnancy and perinatal outcomes. Few severe cases associated with medical or systematic causes leads to serious catastrophic events which can be avoided by increasing antenatal surveillance and appropriate management by multidisciplinary team of obstetrician, hematologist, anesthesiologist, neonatologist and physician

A clinical study of acute intestinal obstruction in adults-based on etiology, severity indicators and surgical outcome

Background: Patients with bowel obstruction still represent some of the most difficult and vexing problems that surgeons face today. While the adage, “never let the sun rise or set on a bowel obstruction” remains true, there has been a trend towards selective non-operative management of this problem. Aims and objectives were to study the various causes and modes of presentation of intestinal obstruction and to evaluate the importance of different severity indicators of obstruction with early recognition, diagnosis and thus timely abdominal exploration.Methods: 2 years prospective study conducted in PDMMC college, Amravati, Maharashtra, India, from September 2013 to September 2015. Each intestinal obstruction patient was evaluated with specific severity indicators, scored and then analyzed.Results: The commonest cause of intestinal obstruction in adults in this study series was adhesions in 33.33% cases. Other causes were mesenteric ischaemia, i.e. 7 (11.67%), Koch’s abdomen, i.e. 5 (8.33%), sigmoid volvulus, i.e. 5 (8.33%) and carcinoma, i.e. 5 (8.33%). Resection anastomosis was most commonly performed procedure in 45.7 % cases, followed by adhesiolysis in 14% patients. 66.66% patients having a score less than 3 were managed conservatively, 95.83 % having a score of 3 or more where operated on.Conclusions: The evaluation of patients endeavours not only to confirm the diagnosis but also to determine the need for and timing of surgery. Certain severity indicators and scoring systems can help to optimize this timing of surgery and prevent mortality

SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal

The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious can be well calibrated and any calibration residual does not mimic the signal. SARAS is an ongoing experiment that aims to detect the global 21 cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additives leave no residuals with Fourier amplitudes exceeding 2~mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS~2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom

An Upper Limit on the Reflected Light from the Planet Orbiting the Star tau Bootis

The planet orbiting tau Boo at a separation of 0.046 AU could produce a reflected light flux as bright as 1e-4 relative to that of the star. A spectrum of the system will contain a reflected light component which varies in amplitude and Doppler-shift as the planet orbits the star. Assuming the secondary spectrum is primarily the reflected stellar spectrum, we can limit the relative reflected light flux to be less than 5e-5. This implies an upper limit of 0.3 for the planetary geometric albedo near 480 nm, assuming a planetary radius of 1.2 R_Jup. This albedo is significantly less than that of any of the giant planets of the solar system, and is not consistent with certain published theoretical predictions.Comment: 5 pages, 1 figure, accepted by ApJ Letter