207 research outputs found
Specification and Verification of Context-dependent Services
Current approaches for the discovery, specification, and provision of
services ignore the relationship between the service contract and the
conditions in which the service can guarantee its contract. Moreover, they do
not use formal methods for specifying services, contracts, and compositions.
Without a formal basis it is not possible to justify through formal
verification the correctness conditions for service compositions and the
satisfaction of contractual obligations in service provisions. We remedy this
situation in this paper. We present a formal definition of services with
context-dependent contracts. We define a composition theory of services with
context-dependent contracts taking into consideration functional,
nonfunctional, legal and contextual information. Finally, we present a formal
verification approach that transforms the formal specification of service
composition into extended timed automata that can be verified using the model
checking tool UPPAAL.Comment: In Proceedings WWV 2011, arXiv:1108.208
Use of Soft Computing Techniques for Transducer Problems
In many control system applications Linear Variable Differential Transformer (LVDT) plays an important role to measure the displacement. The performance of the control system depends on the performance of the sensing element. It is observed that the LVDT exhibits the same nonlinear input-output characteristics. Due to such nonlinearities direct digital readout is not possible. As a result we employ the LVDTs only in the linear region of their characteristics. In other words their usable range gets restricted due to the presence of nonlinearity. If the LVDT is used for full range of its nonlinear characteristics, accuracy of measurement is severely affected. So, to reduce this nonlinearities different ANN techniques is being used such as single neuron structure, MLP structure, RBFNN and ANFIS structure.
Another problem considered here is with flow measurement. Generally flow measurements uses conventional flow meters for feedback on the flow-control loop cause pressure drop in the flow and in turn lead to the usage of more energy for pumping the fluid. An alternative approach for determining the flow rate without flow meters is thought. The restriction characteristics of the flow-control valve are captured by a neural network (NN) model. The relationship between the flow rate and the physical properties of the flow as well as flow-control valve, that is, pressure drop, pressure, temperature, and flow-control valve coefficient (valve position) is found. With these accessible properties, the NN model yields the flow rate of fluid across the flow-control valve, which acts as a flow meter. The viability of the methodology proposed is illustrated by real flow measurements of water flow which is widely used in hydraulic systems.
Control of fluid flow is essential in process-control plants. The signal of flow measured using the flow meter is compared with the signal of the desired flow by the controller. The controller output accordingly adjusts the opening/closing actuator of the flow-control valve in order to maintain the actual flow close to the desired flow. Typically, flow meters of comparatively low cost such as turbine-type flow meters and venturi-type meters are used to measure the volumetric quantity of fluid flow in unit time in a flow process. However, the flow
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meter inevitably induces a pressure drop in the flow. In turn, this results in the use of more energy for pumping the fluid. To avoid this problem, non-contact flow meters, i.e. electromagnetic-type flow meters, have been developed and are widely used in process plants not only because there is no requirement for installation in the pipeline but also because introduction to the differential pressure across pipelines is not necessitated. Unfortunately, the cost of such non-contact measurement is comparatively much higher than that of its conventional counterparts.
Here, an alternative approach is proposed to obtain the fluid flow measurement for flow-control valves without the pressure drop and the consequent power loss that appear in conventional flow meters. Without the flow meter, it is a fact that the flow rate can be determined from the characteristics of the control valve for flow measurements. In this method, the restriction characteristics of the control valve embedded in a neural network (NN) model are used in determining the flow rate instead of actual measurement using a conventional flow meter.
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Prevalence, Causes and Patterns of Anxiety Towards Examinations and Attitude Towards Coping: a Study Among Medical Students
DergiPark: 379052tmsjAims: The objective of this study is to assess symptoms of test anxiety among medical students and its association with various academic, social and health-related factors. The specific aims are to determine: the prevalence of symptoms of test anxiety, the factors responsible for and different patterns of test anxiety, the correlation of socio-demographic data with test anxiety in medical students and the attitude towards coping strategies developped by them to deal with test anxiety.Methods: A sample size of 200 medical students meeting the inclusion criteria and giving consent was chosen from all professional years from the Ras Al-Khaimah Medical and Health Sciences University. The tools used were Visual Analogue Scale indicating severity of anxiety, Test Anxiety Inventory, and a self-designed questionnaire to correlate the various predisposing factors.Results: Results showed 45.5% of the students felt severe examination-related anxiety. Female gender, peer pressure, insufficient sleep, mealtime irregularity, inability to concentrate, concern about previous examination results, perception of the course load as heavy and interpersonal issues were found to be correlated with the severity of examination-related anxiety.Conclusion: Examination-related anxiety has a great impact on medical students, often leading to maladaptive behaviors which may have a negative effect on both examination performance and long-term mental and physical health. We recommend that students receive counseling to cope with this anxiet
Autologous hematopoietic stem cell transplantation-10 years of data from a developing country
Intensive chemotherapy followed by autologous stem cell transplantation is the treatment of choice for patients with hematological malignancies. The objective of the present study was to evaluate the outcomes of patients with mainly lymphoma and multiple myeloma after autologous stem cell transplant. The pretransplant workup consisted of the complete blood count, an evaluation of the liver, kidney, lung, and infectious profile, chest radiographs, and a dental review. For lymphoma, all patients who achieved at least a 25% reduction in the disease after salvage therapy were included in the study. Mobilization was done with cyclophosphamide, followed by granulocyte colony-stimulating factor, 300 g twice daily. The conditioning regimens included BEAM (carmustine, etoposide, cytarabine, melphalan) and high-dose melphalan. A total of 206 transplants were performed from April 2004 to December 2014. Of these, 137 were allogeneic transplants and 69 were autologous. Of the patients receiving an autologous transplant, 49 were male and 20 were female. Of the 69 patients, 26 underwent transplantation for Hodgkin\u27s lymphoma, 23 for non-Hodgkin\u27s lymphoma, and 15 for multiple myeloma and 4 and 1 for Ewing\u27s sarcoma and neuroblastoma, respectively. The median age ± SD was 34 ± 13.1 years (range, 4-64). A mean of 4.7 * 10⁸ ± 1.7 mononuclear cells per kilogram were infused. The median time to white blood cell recovery was 18.2 ± 5.34 days. Transplant-related mortality occurred in 10 patients. After a median follow-up period of 104 months, the overall survival rate was 86%. High-dose chemotherapy, followed by autologous stem cell transplant, is an effective treatment option for patients with hematological malignancies, allowing further consolidation of response
Factor VII deficiency and pregnancy: a case report and review of literature
Factor VII deficiency is one of the \u27rare inherited disorders of coagulation.\u27 Few cases of Factor VII deficiency have been reported during pregnancy, a state which could potentially cause fatal haemorrhage. Here we report a case of a pregnant lady with a history of heavy menorrhagia and multiple first pregnancy failures. Delivery was carried out via Caesarean section due to non-reassuring foetal heart monitoring. Patient was treated with Fresh Frozen Plasma (FFPs) and Factor VII concentrates, however, the patient developed bleeding postoperatively. Literature indicates that whilst Factor VII levels rise during pregnancy in normal women, no increase is seen in homozygous cases, whereas there is a moderate rise in heterozygous individuals. History of heavy menorrhagia, multiple first pregnancy failures and a positive family history for bleeding disorders necessitate investigation and monitoring of Factor VII levels during pregnancy. Factor VII concentrates achieve adequate homeostasis in most cases. Recombinant Factor VIIa, however, is the treatment of choice and does not carry a risk of infection transmission or thrombus formation
Successful use of rituximab in Evans syndrome and refractory immune thrombocytopenic purpura
Immune cytopenias are mediated by auto-antibodies produced by B-lymphocytes. Conventional treatment of immune-mediated haematological disorders includes immunosuppression with steroids and other immune modulating therapies and in some refractory cases, splenectomy. Response rates to conventional and second-line agents are variable and a proportion of patients require lifelong immunosuppression to maintain the disease in remission. Rituximab, an anti- CD 20 monoclonal antibody has gained widespread acceptance in the management of B-cell malignancies. Additionally, it has been used to treat the disorders associated with autoantibody production. We report herein the successful use of Rituximab in the treatment of two patients with autoimmune cytopenias one had Evan\u27s syndrome and other had refractory immune thrombocytopenic purpura. Both of these patients are still in remission at 16 and 25 months following treatment
Frequency and clinical spectrum of rare inherited coagulopathies--a tricenter study
OBJECTIVE: To determine the frequency of rare inherited coagulopathies at three centers of haematology in Karachi and to study the clinical spectrum and laboratory data of these coagulopathies.
METHODS: This was a descriptive study conducted from September 2003 to December 2004 on subjects from Aga Khan University Hospital, Husaini Blood Bank and Fatimid Blood Transfusion Centre. All the subjects with bleeding tendency without any acquired causes of bleeding were selected for further investigation, and were asked relevant questions as present in the questionnaire. Screening tests including platelet count, PT, APTT and bleeding time were performed on all patients and subsequently, specific tests including factor assay, clot solubility test, platelet aggregation and vWFAg were performed.
RESULTS: In total, 1100 patients were evaluated for bleeding tendency at the three centers and 65 patients were diagnosed to have inherited coagulopathy other than haemophilia A and B. Out of these 65 patients, 33 (50.7%) were males and 32 (49.2%) were females. Rare inherited coagulopathies that were found in our population included deficiency of factor VII {n = 21 (32.3%)}, factor X {n = 17 (26.1%)}, factor XIII {n =14 (21.5%)}, factor V {n = 9 (13.8%)}, fibrinogen {n = 2 (3%)}, prothrombin {n = 1 (1.5%)} and factor XII {n = 1 (1.5%)}.
CONCLUSION: Inherited coagulopathies other than haemophilia A and B were noted in the study population
Efecto de la ración de alimento y la temperatura sobre el metabolismo de la carpa dorada
El presente experimento trata de examinar el efecto de la temperatura sobre el metabolismo de la carpa dorada (Carassius auratus), y comprobar, a su vez, si este efecto se ve alterado por el tiempo de exposición a dichatemperatura y/o por la ración de alimento suministrado. Para ello, se expuso a los organismos a diferentes condiciones de disponibilidad de alimento (ayuno y alimento) y a diferentes temperaturas(13C y 18C). Para la determinación del metabolismo se efectuaron respirometrías, tomando el consumo de oxígeno como resultado indirecto del metabolismo. Tras el tratamiento estadístico, se observó un efecto muy significativo de la ración sobre el metabolismo. Aunque en menor medida, también existióun efecto significativo de la temperatura en dicho parámetro. Sin embargo, no se observaron grandes cambios entre la tasa metabólica de las temperaturas analizadas. Por lo tanto, las carpas doradas poseen mecanismos de compensación a corto plazo, gracias a los cuales mantienen una moderada dependencia térmica del metabolismo
Clinico-pathological profile and outcomes of patients with polycythaemia vera, essential thrombocythaemia and idiopathic myelofibrosis: a tertiary care center experience from southern Pakistan
Background: The “Philadelphia Negative Classic Myeloproliferative Neoplasms” include polycythaemia vera (PV), essential thrombocythaemia (ET) andidiopathic myelofibrosis (IMF). These three disorders share several clinical and laboratory features including JAK2 V617F mutation. Our objectives were to determine the clinicoat hological profile and outcomes of Pakistani patients with polycythaemia vera (PV), essential thrombocythaemia (ET) and idiopathic myelofibrosis (IMF) in order to have an insight regarding behaviour of these conditions. Methods: A retrospective analysis of all the cases of PV, ET and IMF diagnosed at our institute from January 1995 to December 2013 was performed.Age, gender, clinical presentation, laboratory investigations, treatment provided and duration of follow up were included for analysis. Appropriatestatistics were utilized for calculation of data. Results: A total of 58 patients were diagnosed as PV, ET or IMF during the study period. Male to female ratio was 1.1:1Forty five percent (n=2) patients came to medical attention due to abnormal laboratory results, 3 had cerebrovascular events, 3 had pruritus, and 1 patient each with gangrene and BuddChiari syndrome. Haemorrhag was not seen in any patient. Sixty percent (n=35) patients were treated with phlebotomy, hydroxyurea and aspirin alone or in combination. None of the patients transformed to myelofibrosis (MF) ormyelodysplasia (MDS) during the mean (±SD) followupperiod of 57.2±50 months.One patient with ET transformed to acute myeloid leukaemia9 yearsafter the diagnosis. Conclusions: This study demonstrated a relatively more benign form of PV, ET and IMF with lesser frequency of symptoms, good response to treatment andless likelihood of transformation to MF, MDS or AM
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