Throughput analysis for cognitive radio networks with multiple primary users and imperfect spectrum sensing

In cognitive radio networks, the licensed frequency bands of the primary users (PUs) are available to the secondary user (SU) provided that they do not cause significant interference to the PUs. In this study, the authors analysed the normalised throughput of the SU with multiple PUs coexisting under any frequency division multiple access communication protocol. The authors consider a cognitive radio transmission where the frame structure consists of sensing and data transmission slots. In order to achieve the maximum normalised throughput of the SU and control the interference level to the legal PUs, the optimal frame length of the SU is found via simulation. In this context, a new analytical formula has been expressed for the achievable normalised throughput of SU with multiple PUs under prefect and imperfect spectrum sensing scenarios. Moreover, the impact of imperfect sensing, variable frame length of SU and the variable PU traffic loads, on the normalised throughput has been critically investigated. It has been shown that the analytical and simulation results are in perfect agreement. The authors analytical results are much useful to determine how to select the frame duration length subject to the parameters of cognitive radio network, such as network traffic load, achievable sensing accuracy and number of coexisting PUs

INVESTIGATION OF SINGLE-PHASE FLOW CHARACTERISTICS IN A STAGGER PIN-FINS COMPLEX GEOMETRY

The cooling equipment project must use electrical and electronic equipment because of the need to remove the heat generated by this equipment. Investigation; R-113 single-phase flow heat transfer; (50 x 50 mm2) cross-section and (5 mm) height; used in a series of stagger-square micro-pin fins. Inlet temperature of (25 °C); (6) Mass flow rate at this temperature, the recommended range is (0. 0025 -0.01 kg/sec) the inlet and outlet pressures are approximately (1-1.10 bar), and through (25- 225 watts) applied heat. The iterative process is used to obtain the heat flow characteristics, for example; the single-phase heat transfer coefficient is completely laminar flow developing, in this flow, guesses the wall temperature, guess the fluid temperature. The possible mechanism of heat transfer has been discussed.

A new four-dimensional hyper-chaotic system for image encryption

Currently, images are very important with the rapid growth of communication networks. Therefore, image encryption is a process to provide security for private information and prevent unwanted access to sensitive data by unauthorized individuals. Chaos systems provide an important role for key generation, with high randomization properties and accurate performance. In this study, a new four-dimensional hyper-chaotic system has been suggested that is used in the keys generation, which are utilized in the image encryption process to achieve permutation and substitution operations. Firstly, color bands are permuted using the index of the chaotic sequences to remove the high correlation among neighboring pixels. Secondly, dynamic S-boxes achieve the principle of substitution, which are utilized to diffuse the pixel values of the color image. The efficiency of the proposed method is tested by the key space, histogram, and so on. Security analysis shows that the proposed method for encrypting images is secure and resistant to different attacks. It contains a big key space of (2627) and a high sensitivity to a slight change in the secret key, a fairly uniform histogram, and entropy values nearby to the best value of 8. Moreover, it consumes a very short time for encryption and decryption

Metabolic and pharmacological observations during drug treatment of epilepsy

The thesis reports studies on patients with epilepsy. The effects of two newly introduced anticonvulsant agents are discussed with regard to the seizure control, side effects, serum levels and their effect on the metabolism of other anticonvulsant drugs when used in combination. Some of the metabolic changes induced by anticonvulsant medication are reported. The introduction to the thesis gives an account of the general mode of action of anticonvulsant drugs, and indicates the continual search for the ideal anticonvulsant. The methods used in various analyses in this thesis are described. The thesis is then divided into two sections. The first deals with the comparative trial of the two newly introduced anticonvulsant agents, i.e. sodium valproate (EPILIM) and clonazepam (RIVOTRIL). The two drugs were studied in a cross-over trial in 32 chronic epileptic patients who were showing poor control; one of the trial drugs was added to the existing therapy for a period of 12 weeks, after which the patients took the second drug. Sodium valproate was the more effective drug with the least side effects. However, sodium valproate had more effect on other serum anticonvulsant drug levels: it increased the serum levels of pheno-barbitone and reduced those of phenytoin in some patients. The second section of the thesis deals with two of the changes in metabolism induced by the chronic intake of anticonvulsant drugs. Chapters 3, 4 and 5 deal with the incidence of serum IgA depletion, the effect of anticonvulsants on secretory IgA, the relation of serum IgA depletion to the HLA status, and the effect anticonvulsants have on lymphocyte protein synthesis. The results show that roughly one fourth of the patients studied had reduced serum IgA levels, and this directly related to the intake of phenytoin. The reduction in serum IgA was not found to be reflected on the active form of IgA, viz, secretory IgA; although found to be reduced, this was to a much lesser degree than that of the serum. The reduction in serum IgA in patients on phenytoin was related to the higher incidence of a specific HLA pattern in these patients. HLA-A2 was much more prevalent in these patients than in patients on the same medication but who did not have a low serum IgA level. Lymphocyte protein synthesis was found to be reduced in all patients on anticonvulsants when compared to controls. During the IgA studies serum folate was measured, and it was found to be reduced in 90% of the patients. This was further studied in Chapters 7 and 8. Serum folate was found to be reduced in most of the patients studied. Those who had the lowest serum folate levels had CSF examination for folate, which was found to be reduced as well. The effects of treating patients with low serum and CSF folate is reported. The treatment was with folic acid or with 5-formyltetrahydrofolate. The effects of treatment on seizure frequency, serum anticonvulsant levels and CSF amine metabolites (HVA and HIAA) were studied. The results show that CSF folate increased more with 5-formyltetrahydrofolate treatment. Serum phenytoin levels were reduced with treatment, and the levels of HVA and HIAA were reduced with 5-formyl-tetrahydrofolate; there was, however, no effect on seizure frequency

Incidence of reexploration in cardiac surgery under cardio pulmonary bypass

INTRODUCTION: Cardiac Surgery being the most modern and conceptualized surgery which involves cardiopulmonary bypass Clotting Mechanism, Temperature Control, Haemodilution and Cardiolegic arrest, etc. The failure off any off these mechanisms ends up in a cascading effect of morbidity and mortality of the patients. The complications associated in the post operative period like cardiac failure renal dysfunction, pulmonary dysfunction and cerebrovascular accident play a major role in determining the outcome. Post operative bleeding and Reexploration are inherent complications associated with cardiac surgery. The Adverse out come as a result of postoperative bleeding and Reexploration has been the subject of the present study. AIMS OF THE STUDY: The present study was primarily undertaken to study the incidence off Reexploration in Cardiac Surgery among patients subjected to cardio pulmonary bypass at department off cardio thoracic surgery, Madras Medical College, Chennai. Thereby identifying the factors contributing to Reexploration and adapting suitable measures to reduce the incidence of Reexploration. Reexploration remains a inherent complication associated with open heart surgery which in turn contributes towards increased morbidity, prolonged hospitalization infection, multiple organ dysfunction and even death. OBJECTIVES: To assess mortality and risk factors associated with Reexploration for hemorrhage in patients under going open heart surgery. To initiate appropriate steps in reducing the incidence of Reexploration. During the course of this study an effort has been made to highlight the cost off hospitalization resulting from Reexploration. The incidence of complications resulting from the same and the their management. The pre, intra and post operative measures that play a vital role have been stressed upon. MATERIALS AND METHODS: The present study was conducted at Department of Cardio thoracic Surgery, Madras Medical College, Govt. General Hospital, Chennai. From September 2004 to March 2007. Among 1131 patients who underwent cardiac surgery under cardio pulmonary bypass. Patients who had problem of bleeding underwent Reexploration. An overall incidence of Reexploration was 2.12% (24 / 1131) of patients. Patients included in the study belonged to both sexes and age groups varying from 11 to 68 years. The patients were subjected to routine investigations. CONCLUSIONS: Attention towards meticulous haemostasis prior to closure is Mandatory. Sound surgical technique will reduce incidence of bleeding from sites of Cannulation and Anastomosis. Adoption OFF PUMP CABG has shown to reduce incidence of post operative bleeding and Morbidity when compare to ON PUMPCABG. Adoption of Hemostatic Technique for internal mammary artery anastomotic bleeding by which hemostasis can be achieved without the risk of anastomotic stenosis or aggravation of the bleeding, as it avoids placing sutures over the anastomotic suture line. Patients predicted to have increased risks of bleeding may benefit from prophylactic use of aprotinin, aminocaproic acid, or other agents shown to reduce hemorrhage. The inherent risk of complications in a patient undergoing Open Heart Surgery can the avoided by encouraging TRANSCATHETER, MITRAL VALVOPLASTY, AORTIC VALVOPLASTY, PULMONARY VALVOPLASTY, and clam shell closure of ATRIAL SEPTAL DEFECT

Influence of chemical and physical conditions on the production of bacteriocin by Aeromonas hydrophila

Aeromonas hydrophila have been isolated as a cause of a cute gastroenteritis in 23 (5.6%) of 410 patients. Other bacterial enteropathogens have been isolated from 387 patients with diarrhea, were 19 different strains. A. hydrophila occurred more commonly in children with acute diarrhea, the results showed that 18(78.26%) isolates of A. hydrophila found in children under 10 years old ,distributed to 10(43.47%) in male and 8(34.78%) in female ,and in adults with diarrhea 5 (21.73%). In the other hand, we noticed frequency of isolation was higher in male 14(60.86%) when compared with 9(39.14%) in female. Six strains of A. hydrophila have been observed to have bacteriocin activity against 12 of 23 different A. hydrophila ,as well as Staphylococcus aureas, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacea and Shigella dysenteria. The results showed Bacteriocin-like substances (BLS11) had isoinhibitory activity on 10 same A. hydrophila species and heteroinhibitory activity effects on all pathogenic bacterial strains used, while BLS5 showed isoinhibitory activity on 2 same A. hydrophila species and heteroinhibitory activity by effecting on gram negative only, and BLS3& BLS12 showed activity on E. coli isolates only, and none of BLS1& BLS10(isoinhibitory activity on 1 A.hydrophila respectively) had effect on all pathogenic bacteria. Among the standard laboratory media used Brain Heart Infusion broth (BHI) showed the maximum production and poor yields resulted from growth in Peptone Glyserol (PG) and Nutrient broth. We selected BLS11 to their wide range effect on same species and enteric pathogenic strains, to study the Influence of chemical and physical conditions on the production of BLS by A.hydrophila. The BLS11 preparations from A.hydrophila11 strains of A. hydrophila were tolerant to all three treatments of surfactant. In the other hand, effect of organic acid on BLS production BLS11 has been studied and showed no remarkable difference in zone of inhibition when used acetone as affecter element, while both of isopropanol and ethanol have narrow inhibition zone range when compared with control strain. These results indicated that most A. hydrophila might be harboring plasmid mediated bacteriocin like substance, and there are no relation between BLS production and number of plasmid bands present in bacteria

Drama as Appears in Samuel Beckett's "Ping" and "How It Is"

This paper Shades light on one of the most important writers in the modern and postmodern age, Samuel Beckett and his novel, and short stories. The paper hypothesizes that Beckett has presents a great amount of drama in his novels and short stories as he used to do in his plays and to achieve that he uses a postmodernist technique which is minimalism. The paper aims at proving the being put hypothesis by following a mixture of formalistic and postmodernist approach which fits the texts and the minimalism technique. The paper ends with the conclusion that sums up the results. Key Words: Beckett, "Ping", "How It Is", Minimalism, postmodernis

Culture Clash in Meera Syal\u27s My Sister-Wife: a Feminist Thematic Study

الصراع الثقافي في مسرحية ضرتي للكاتبة الاسيوية-الانكليزية ميرا سيال هو الموضوع الذي تحاول هذه الورقة أن توضحه. تفترض الورقة أن Syal تحاول تقديم عرض نسوي لموضوع الصدام الثقافي السائد في حياة المهاجرين إلى أوروبا. يهدف البحث إلى التحقق من صحة الفرضية باتب اع منهج تحليل الشخصية. يبدأ البحث بمقدمة للموضوع والكاتب. يقدم البحث مناقشة للنص يلي ذلك الاستنتاج الذي يلخص نتائج التحليل