Dead Reckoning Localization Technique for Mobile Wireless Sensor Networks

Localization in wireless sensor networks not only provides a node with its geographical location but also a basic requirement for other applications such as geographical routing. Although a rich literature is available for localization in static WSN, not enough work is done for mobile WSNs, owing to the complexity due to node mobility. Most of the existing techniques for localization in mobile WSNs uses Monte-Carlo localization, which is not only time-consuming but also memory intensive. They, consider either the unknown nodes or anchor nodes to be static. In this paper, we propose a technique called Dead Reckoning Localization for mobile WSNs. In the proposed technique all nodes (unknown nodes as well as anchor nodes) are mobile. Localization in DRLMSN is done at discrete time intervals called checkpoints. Unknown nodes are localized for the first time using three anchor nodes. For their subsequent localizations, only two anchor nodes are used. The proposed technique estimates two possible locations of a node Using Bezouts theorem. A dead reckoning approach is used to select one of the two estimated locations. We have evaluated DRLMSN through simulation using Castalia simulator, and is compared with a similar technique called RSS-MCL proposed by Wang and Zhu .Comment: Journal Paper, IET Wireless Sensor Systems, 201

Butt fusion welding of polyethylene pipes

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The butt fusion process is extensively used in the joining of polyethylene (PE) pipes by the water and gas industries. This welding process although deceptively simple, is rather poorly understood, with much of the initial developments being of a rather empirical nature. The Water Research centre (WRc) have funded the present research in an attempt to optimise the welding of high pressure pipeline (PE100) systems. The main aims of this research were to investigate the effect of different welding conditions on the physical and mechanical properties of the joints produced and to investigate these effects on the micro- and macro-structures of the joints produced. A series of welds were made using Eltex Tub 124 and Rigidex 002-50 pipes of 180mm diameter. The fusion pressure and heatsoak times were varied. A milling machine witha twin cutter arrangement was used to obtain the test specimens from around the circumference of the pipes. Differential scanning calorimetry was used to study the effect of sample preparation methodology on the thermo-oxidative stability. Polarised light microscopy and image analysis were used to study the macro- and micro-structural developments in the weld joint. Joint strength was evaluated via standard and non-standard tensile test methods. Milling the samples to produce the test specimens was found to decrease significantly the thermo-oxidative resistance of the polymer. Reasons for this behaviour have been proposed. In order to achieve high quality thin films from microtomy, custom-made blades were used. This programme also developed the optimum polishing method for the microtomed blades. The macro-structure of the bead: its shape and dimensions were found to be a function of temperature and pressure. Correlation was found between the bead geometry and the position around the circumference of the pipe. The macrostructures within the weld zone also showed this dependence on the position along the circumference of the pipe. An examination of the microstructures of each weld had shown the presence of five different zones. The feasibility of using microtomed thin sections in a tensile test was demonstrated. The test method provides a means to study failure initiation and propagation in the tensile test specimen. Initial deformation was found to occur in the centre of the melt-affected zone (MAZ) and the final failure occurs at the junction of the weld bead and the bulk polymer. Tests on films without the weld bead showed that maximum deformation occurred at the centre of the sample within the MAZ. The presence of the bead and the asymmetry in the test specimens caused by the welding process were found to have a significant influence on the failure mode and the failure strain. The strain rate was also found to play a significant role in both beaded and debeaded samples. The failure was initiated from the pseudo notches in the beaded samples. In the debeaded sample the failure was within the MAZ

K Wire fixation of supra-condylar humerus fractures in children. Is ulnar nerve at risk?

Abstract OBJECTIVE: To compare iatrogenic ulnar nerve injury in lateral entry pin fixation versus medial and lateral entry pin fixation in the treatment of supracondylar fractures of the humerus in children. Measurement of clinical parameters in terms of elbow range of motion and postop radiographic alignment was also targeted. METHODS: The retrospective cohort study was conducted at Aga Khan University Hospital, Karachi, and comprised data of paediatric patients who underwent closed reduction and percutaneous pin fixation for the treatment of displaced extension type supracondylar fractures of the humerus between July 2007 and June 2012. Data regarding socio-demographic status, disease and procedure variables was collected from patient files and was analysed using SPSS 19. RESULTS: There were 71patients; 37(52%) in the lateral entry group and 34(48%) in the medial and lateral entry group. The two groups were similar in terms of mean age, gender distribution, and preoperative displacement, comminution, and associated vascular and nerve status (p\u3e 0.05 each). There were no cases of iatrogenic ulnar nerve injury in either group and no significant differences between groups with respect to the elbow range of motion and radiological parameters (p\u3e 0.05 each). CONCLUSIONS: With the use of the specific techniques employed, both lateral entry pin fixation and medial and lateral entry pin fixation were effective in the treatment of displaced extension type supracondylar humerus fractures in children

Outcomes of internal hemipelvectomy for pelvic tumors: a developing country’s prospective

Introduction: Previously, external hemipelvectomy was the mainstay of treatment for pelvic tumors. However, with technological advancements, limb salvage procedures such as internal hemipelvectomy have emerged as a viable alternative. However, there is limited literature available on long-term outcomes and complications of internal hemipelvectomy, especially from developing countries. Therefore, the objective of this study was to share our experience of internal hemipelvectomy at a tertiary care center in a developing country. Materials and methods: A retrospective review was conducted in which all 24 patients undergoing internal hemipelvectomy from January 1, 2005 to December 31, 2015 at our institution were included. Medical record files were reviewed for intraoperative and early and late postoperative complications, and functional outcomes were assessed by contacting each patient on telephone. Results: Ewing sarcoma was found to be the most common diagnosis, followed by osteosarcoma as the second most common. The mean follow-up period was 18.7 ± 13.9 months. Intraoperatively there were 4 cases of iatrogenic neurovascular injury and 2 cases each of urinary tract injury and dural tear. Four patients developed early wound infections, 7 developed late wound infections, and 2 developed flap necrosis. Three patients developed recurrence, whereas 7 patients developed metastasis postoperatively. The mean survival was calculated to be 28 months and the mean Musculoskeletal Tumor Society score was 19.3 ± 5.2. Conclusions: Outcomes and prevalence of complications shown in this study are comparable to those in the international literature, which suggests that hemipelvectomy is a viable option in developing countries also. However, more such studies are warranted to validate the findings and to identify the challenges and morbidities associated with hemipelvectomy in Asian and developing countries

Rotational mal-alignment after reamed intramedullary nailing for tibial shaft fracture

Abstract Intra-medullary (IM) nailing is standard of care for unstable tibial shaft fractures. Malrotation is very common but it is under-recognised, inpart because of variation in normal anatomy and partly due to difficulty in accurately assessing rotation. This study was planned to evaluate the frequency of rotational mal-alignment after reamed tibia IMnailing. This cross-sectional study was conducted at Aga khan University Hospital, Karachi, and comprised patients with tibia shaft fractures managed with IMnailing from January to December 2014. All the patients were assessed intra-operatively for rotational alignment using the knee and ankle fluoroscopic images. There were 81 patients with a mean age of 38±16.9 years. There were 64(79%) male patients. Overall the incidence of malrotation was in 20(24.7%) cases. Rotational mal-alignment is one of the preventable complications after IMnailing which can be assesed intra-operatively under fluoroscope

Renoprotection, renin inhibition, and blood pressure control: the impact of aliskiren on integrated blood pressure control

Hypertension (HTN) is an important factor in progressive loss of renal function. The kidney can be both a contributor to and a target of HTN. The functional integrity of the kidney is vital for the maintenance of cardiovascular homeostasis. Chronic activation of the renin system causes HTN and, ultimately, end-organ damage. Direct renin inhibitors (DRIs) inhibit plasma renin activity (PRA), thereby preventing the conversion of angiotensinogen to angiotensin I; consequently, the levels of both Ang I and Ang II are reduced. There is no compensatory increase in PRA activity with DRIs as seen with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). There are reasons to speculate that renin inhibition might prove to be a superior strategy for blocking the renin–angiotensin–aldosterone system compared with ACEIs or ARBs. Evidence for the efficacy of aliskiren (a DRI) is considered to be relatively strong, based on published, short-term, double-blind, randomized, controlled trials showing that aliskiren is as effective as other antihypertensive agents in reducing blood pressure (BP), with no rebound effects on BP after treatment withdrawal. When combined with diuretics, fully additive BP reduction is seen. When given with an ACEI or ARB, aliskiren produces significant additional BP reduction indicative of complimentary pharmacology and more complete renin–angiotensin system blockade

Outcome of Judet\u27s quadricepsplasty for knee contractures and the effect of local infiltration of epinephrine on reducing blood loss

Objective: To evaluate the effectiveness of Judet\u27s quadricepsplasty for treatment of knee contractures and to identify the effect of local infiltration of epinephrine on blood loss associated with this procedure.Methods: A retrospective cohort study was conducted in which all cases of knee contractures managed with Judet\u27s quadricepsplasty from 1st January 2009 to 31st December 2013 were included and were divided into two groups. The epinephrine group included patients who were infiltrated with diluted epinephrine (1:400,000) along with xylocaine, around the operative field 15 min prior to the incision time, while the control group did not receive any infiltration. Judet\u27s outcome, blood loss, drop in hemoglobin and required blood transfusion were noted for all patients and compared between both groups.Results: Most common preceding pathology identified for the development of knee contractures was periarticular fracture while ilizarov application was the most common etiology. Both groups were found similar in all preoperative characteristics except preoperative flexion contracture (p = 0.02). All functional outcome measures including Judet\u27s outcome were similar in both groups. In contrast, duration of surgery (p = 0.01), blood loss (p = 0.02), drop in hemoglobin (p = 0.01) and number of transfusions (p = 0.03) were significantly reduced in epinephrine group.Conclusion: Judet\u27s quadricepsplasty is a useful procedure to increase the range of motion of rigid knees and local infiltration of epinephrine is effective in decreasing the amount of subsequent blood loss and transfusion requirements

Problems of Political Development in Bangladesh

After World War II the revival of the spirit of nationalism led to the emergence of many new states. Freed from the colonial domination, the new states were keenly interested in developing their societies as fast as possible. Many problems stand in the way of development. These problems are the problems of stability, unity, integration and socioeconomic problems. This study is concerned about the problems of political development in Bangladesh, which came into existence in 1971, as a result of the problems of of national integration in Pakistan. This study identifies some problems which stand in the way of political development in Bangladesh. These problems are: (1) the problems of integration, (2) the problems of unity and stability, (3) the lack of well-organized political parties, (4) the problems of bureaucracy, and (5) socio-economic problems. After the creation of Bangladesh it was assumed that there would be no problem of integration in Bangladesh. But an analysis of the political situations will show that problems of integration still remain, though in different character, such as the lack of integration between the elites and the mass, the lack of integrative ideology, the separatist tendency in the tribal people, etc. Absence of stability is creating problems in the effective undertaking of any developmental plan. The chief causes of instability are: factionalism, frustration of the people, threat of India, loss of charisma, etc. Too many political parties with too many ideologies stand in the way of creating a stable government. The parties do not have any organizational basis, and are based on the personality of the leader. The parties are not effective in aggregating the peoples\u27 demands and grievances. The lack of balance in the role of the bureaucracy is also a problem. On the one hand, if the bureaucrats are given more power, they hinder the growth of political institutions. On the other hand, if they are given less power, they play an inactive role hindering the execution of policies. Bangladesh suffers from both the problems of bureaucracy. The most pre-dominant problems which hamper political development in Bangladesh are socio-economic problems. The population problem, food problem, and unemployment create mass frustrations causing instability and disunity within the country. The attachment to the traditional values hinders the way of change. This study analyzes in detail all these problems and how they stand in the way of political development

Cognitive Experiments and Features for Computing Mental Stress

In this paper, mental stress is computed through cognitive experiments that induce stress. In a controlled laboratory environment, a group of students are involved in a series of mental challenges. While performing the cognitive tasks, stress is induced on the participants. Deep breathing exercise is performed in the start of experiments and then in between each activity to make the conditions normal and a participant feels relaxed. Various physiological features are recorded during experimental activities. Also, cerebral features are recorded that provide improved classification results. The severity of stress is different on each participant but the purpose of experimental protocol is to separate stressful conditions from relaxed environment. Support Vector machine (SVM) is used to identify relax or normal class from a number of stressed classes. It is shown that cerebral features improve the classification accuracy with a satisfactory margin and designed protocol system is able to compute the severity of induced stress