Counteracting Selfish Nodes Using Reputation Based System in Mobile Ad Hoc Networks

A mobile ad hoc network (MANET) is a group of nodes constituting a network of mobile nodes without predefined and pre-established architecture where mobile nodes can communicate without any dedicated access points or base stations. In MANETs, a node may act as a host as well as a router. Nodes in the network can send and receive packets through intermediate nodes. However, the existence of malicious and selfish nodes in MANETs severely degrades network performance. The identification of such nodes in the network and their isolation from the network is a challenging problem. Therefore, in this paper, a simple reputation-based scheme is proposed which uses the consumption and contribution information for selfish node detection and cooperation enforcement. Nodes failing to cooperate are detached from the network to save resources of other nodes with good reputation. The simulation results show that our proposed scheme outperforms the benchmark scheme in terms of NRL (normalized routing load), PDF (packet delivery fraction), and packet drop in the presence of malicious and selfish attacks. Furthermore, our scheme identifies the selfish nodes quickly and accurately as compared to the benchmark scheme

Sudden Unexpected Natural Death in the Youth; an Iranian Single Center Investigation

Background: Sudden unexpected natural death (SUND) has not been studied in Iran. Herein we investigated its main causes in our country.Methods: Records of 80 cases registered to a single referral center were investigated to determine the distribution of sex, age, and etiology of death.Results: Fifty eight (72.5%), 6 (7.5%), 6 (7.5%) and 4 (5%) of our cases have died due to various types of heart diseases, cerebral events, pulmonary emboli and gastrointestinal bleeding (GIB), respectively. Moreover, men are victims of SUND more that women (83.7% vs.16.3%, respectively).Conclusion: Policies should be planned by the governments to prevent youth mortality in societies. These attempts should especially target ischemic heart disease

One-transit paths and steady-state of a non-equilibrium process in a discrete-time update

We have shown that the partition function of the Asymmetric Simple Exclusion Process with open boundaries in a sublattice-parallel updating scheme is equal to that of a two-dimensional one-transit walk model defined on a diagonally rotated square lattice. It has been also shown that the physical quantities defined in these systems are related through a similarity transformation.Comment: 8 pages, 2 figure

Two-dimensional shock capturing numerical simulation of shallow water flow applied to dam break analysis

With the advances in the computing world, computational fluid dynamics (CFD) is becoming more and more critical tool in the field of fluid dynamics. In the past few decades, a huge number of CFD models have been developed with ever improved performance. In this research a robust CFD model, called Riemann2D, is extended to model flow over a mobile bed and applied to a full scale dam break problem. Riemann2D, an object oriented hyperbolic solver that solves shallow water equations with an unstructured triangular mesh and using high resolution shock capturing methods, provides a generic framework for the solution of hyperbolic problems. The object-oriented design of Riemann2D has the flexibility to apply the model to any type of hyperbolic problem with the addition of new information and inheriting the common components from the generic part of the model. In a part of this work, this feature of Riemann2D is exploited to enhance the model capabilities to compute flow over mobile beds. This is achieved by incorporating the two dimensional version of the one dimensional non-capacity model for erodible bed hydraulics by Cao et al. (2004). A few novel and simple algorithms are included, to track the wet/dry and dry/wet fronts over abruptly varying topography and stabilize the solution while using high resolution shock capturing methods. The negative depths computed from the surface gradient by the limiters are algebraically adjusted to ensure depth positivity. The friction term contribution in the source term, that creates unphysical values near the wet/dry fronts, are resolved by the introduction of a limiting value for the friction term. The model is validated using an extensive variety of tests both on fixed and mobile beds. The results are compared with the analytical, numerical and experimental results available in the literature. The model is also tested against the actual field data of 1957 Malpasset dam break. Finally, the model is applied to simulate dam break flow of Warsak Dam in Pakistan. Remotely sensed topographic data of Warsak dam is used to improve the accuracy of the solution. The study reveals from the thorough testing and application of the model that the simulated results are in close agreement with the available analytical, numerical and experimental results. The high resolution shock capturing methods give far better results than the traditional numerical schemes. It is also concluded that the object oriented CFD model is very easy to adapt and extend without changing the generic part of the model.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Two-dimensional shock capturing numerical simulation of shallow water flow applied to dam break analysis

With the advances in the computing world, computational fluid dynamics (CFD) is becoming more and more critical tool in the field of fluid dynamics. In the past few decades, a huge number of CFD models have been developed with ever improved performance. In this research a robust CFD model, called Riemann2D, is extended to model flow over a mobile bed and applied to a full scale dam break problem. Riemann2D, an object oriented hyperbolic solver that solves shallow water equations with an unstructured triangular mesh and using high resolution shock capturing methods, provides a generic framework for the solution of hyperbolic problems. The object-oriented design of Riemann2D has the flexibility to apply the model to any type of hyperbolic problem with the addition of new information and inheriting the common components from the generic part of the model. In a part of this work, this feature of Riemann2D is exploited to enhance the model capabilities to compute flow over mobile beds. This is achieved by incorporating the two dimensional version of the one dimensional non-capacity model for erodible bed hydraulics by Cao et al. (2004). A few novel and simple algorithms are included, to track the wet/dry and dry/wet fronts over abruptly varying topography and stabilize the solution while using high resolution shock capturing methods. The negative depths computed from the surface gradient by the limiters are algebraically adjusted to ensure depth positivity. The friction term contribution in the source term, that creates unphysical values near the wet/dry fronts, are resolved by the introduction of a limiting value for the friction term. The model is validated using an extensive variety of tests both on fixed and mobile beds. The results are compared with the analytical, numerical and experimental results available in the literature. The model is also tested against the actual field data of 1957 Malpasset dam break. Finally, the model is applied to simulate dam break flow of Warsak Dam in Pakistan. Remotely sensed topographic data of Warsak dam is used to improve the accuracy of the solution. The study reveals from the thorough testing and application of the model that the simulated results are in close agreement with the available analytical, numerical and experimental results. The high resolution shock capturing methods give far better results than the traditional numerical schemes. It is also concluded that the object oriented CFD model is very easy to adapt and extend without changing the generic part of the model.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Dapsone hypersensitivity syndrome-rare complication of dapsone therapy

Among several other adverse effects of dapsone therapy, dapsone hypersensitivity syndrome is extremely rare but most life-threatening complication. Here we report a case of severe dapsone hypersensitivity syndrome in a 27-year-old female student diagnosed as immune thrombocytopenic purpura on dapsone therapy who was admitted with remittent fever, lymphadenopathy and skin rash and was managed successfully with drug withdrawal and systemic glucocorticoid therapy. The idea of reporting this case is to recognise the rare potentially life threatening adverse effect of dapsone therapy, its timely diagnosis and favourable outcome with systemic glucocorticoid therapy

Stability of visual acuity after cessation of occlusion therapy in patients of amblyopia

Background: It is generally recognized that most children with amblyopia have an improvement of visual acuity (VA) with treatment, little is known about the course of vision once treatment is decreased or stopped in a child. The treatment of amblyopia in children is frequently discussed in the literature; however, there is a lack of research into which method of treatment cessation is the most appropriate once therapy has been completed. We undertook this specifically designed prospective study to directly compare the potential relationship between the method of therapy cessation and the short-term (12-weeks) recurrence of amblyopia.Methods: Fifty children of 5-14 years of age group with different types of amblyopia fulfilling the inclusion criteria were included in the study. Once BCVA was achieved, the subjects were randomized into one of two groups; abrupt cessation group or therapy tapering group. In subjects of tapered group occlusion was reduced from full-time occlusion to 50% of waking hours at BCVA and then additional by 50% at the 4-week’s study visit with occlusion being discontinued completely at the 8-week’s visit. All subjects in the abrupt cessation group stopped their full-time occlusion completely at the Best corrected visual acuity (BCVA). All subjects were followed for 3 consecutive 4-weeks intervals, for a total of 12 weeks, to assess the short-term recurrence rate of amblyopia.Results: The overall results show that at 12-weeks study outcome visit, 9 of the 50 subjects developed recurrence. Out of the total of 9 recurrences, 5 (20%) occurred in abrupt cessation group and 4 (16%) occurred in gradual cessation group. Comparing the time of occurrence of recurrence of amblyopia between the 2 studied groups, the recurrence of amblyopia was more during first 4 weeks of study 60% in abrupt group, whereas in gradual group all the recurrences occurred between 8 and 12 weeks visits. The pre-treatment VA and BCVA had a significant impact on the recurrence of amblyopia.Conclusions: In present study, the results demonstrate that the overall risk of amblyopia recurrence is 18% and the difference in the risk of amblyopia recurrence between the abrupt cessation group and the gradual cessation group (20% vs. 16%) is not statistically significant

Fatal Subacute Hepatic Failure in a Patient with AA-Type Amyloidosis: Case Report

Although systemic amyloidosis of amyloid-associated protein (AA) type (secondary or reactive amyloidosis) frequently involves the liver, it rarely causes clinically apparent liver disease. Mild elevation of alkaline phosphatase and hepatomegaly are the most common biochemical and clinical findings, respectively. We report a case of systemic amyloidosis of AA type, which clinically presented as subacute hepatic failure and resulted in a fatal clinical course in a 69-year-old man. To the best of our knowledge, this is the fifth case of hepatic amyloidosis of AA type that clinically presented as fatal subacute hepatic failure, an unusual clinical presentation for hepatic involvement by systemic AA-type amyloid

Comparison of serum electrolytes with preeclampsia severity: a cross sectional study

Background: Preeclampsia is a common complication of pregnancy that put women and their fetuses at significant risk and result in life long sequelae. The pathogenesis of this important disease is complex as such the role of different serum electrolytes is being investigated as they are considered important for blood pressure regulation.Methods: A hospital based cross-sectional study of 100 diagnosed cases of preeclampsia divided into mild and severe according to latest International Society for the Study of Hypertension in Pregnancy (ISSHP) guidelines and equal number of age, parity and gestational age matched women (n=100), that acted as control group, with singleton normal pregnancies. Data was analyzed in SPSS V:26. Statistical tests to find out mean standard deviation and One-way ANOVA test were applied to find the significance of associations.Results: In severe preeclampsia group, the mean values of Na+, K+ and Cl- were 134.50±4.24, 4.28±0.74, 106.48±3.41 meq/l respectively in comparison to control group which had 135.57±3.29, 4.12±0.53, 108.20±3.19 meq/l respectively. Results from one way ANOVA showed that there was statistically significant difference between means of the three groups for systolic blood pressure (SBP), diastolic blood pressure (DBP), potassium and chloride levels with p<0.05. A post hoc analysis was used to distinguish the differences in means of these parameters.Conclusions: Estimation of readily available serum electrolytes of sodium potassium and chloride during the course of pregnancy can help to identify and treat preeclampsia and thus reduce the burden of morbidity and mortality in pregnant women

Cytogenetic diagnosis of Roberts SC phocomelia syndrome: First report from Kashmir

There are several syndromes in which specific mitotic chromosomal abnormalities can be seen, like premature centromere separation, premature (sister) chromatid separation, and somatic aneuploidies. Identifications of such specific cytogenetic findings can be the key factor that leads towards the diagnosis of syndromes like Roberts SC phocomelia. The case presented here as Roberts SC phocomelia syndrome was identified as a child with multiple congenital anomalies and dysmorphic features. Conventional cytogenetic analysis of the case revealed premature sister chromatid separation. The premature centromeric separation was also confirmed by C banding analysis of the child. It is the first and the only case of Roberts SC phocomelia diagnosed from this part of the world. The present case report emphasizes the importance of conventional cytogenetics in the diagnosis of such syndromes