Performance Evaluation of Byzantine Fault Detection in Primary/Backup Systems

ZooKeeper masks crash failure of servers to provide a highly available, distributed coordination kernel; however, in production, not all failures are crash failures. Bugs in underlying software systems and hardware can corrupt the ZooKeeper replicas, leading to a data loss. Since ZooKeeper is used as a ‘source of truth’ for mission-critical applications, it should handle such arbitrary faults to safeguard reliability. Byzantine fault-tolerant (BFT) protocols were developed to handle such faults. However, these protocols are not suitable to build practical systems as they are expensive in all important dimensions: development, deployment, complexity, and performance. ZooKeeper takes an alternative approach that focuses on detecting faulty behavior rather than tolerating it and thus providing improved reliability without paying the full expense of BFT protocols. In this thesis, we studied various techniques used for detecting non-malicious Byzantine faults in the ZooKeeper. We also analyzed the impact of using these techniques on the reliability and the performance of the overall system. Our evaluation shows that a realtime digest-based fault detection technique can be employed in the production to provide improved reliability with a minimal performance penalty and no additional operational cost. We hope that our analysis and evaluation can help guide the design of next-generation primary-backup systems aiming to provide high reliability

Maharashtra's three main fish landing centres

Maharashtra's Three Main Fish Landing Centre

Age and growth studies of banana prawn, Penaeus merguiensis de Man from Maharashtra waters

Age and growth of Penaeus merguiensis from Maharashtra waters were studied. The estimates obtained by Bhattacharya analysis and Gulland-Holt plot were L∞ = 203.7 mm and K = 2.15 yr-1 for males and L∞ = 254.9 mm and K = 1.90 yr-1 for females. The maximum size observed for males was 188 mm and 238 mm for females. The male and female prawns after one month larval period attain 134.2 mm and 156.3 mm length in 6 months and 180.0 mm and 216.8 mm in one year respectively

Comparison of haemodynamic responses in normotensive and hypertensive patients among three intubation devices: macintosh laryngoscope, intubating laryngeal mask airway and lightwand

Background: The pressor response to endotracheal intubation is of special concern, especially in the presence of comorbidities like diabetes, hypertension, obesity and ischemic heart disease (IHD). It is commonly assumed that insertion of laryngeal mask airway (LMA) is associated with lesser hemodynamic fluctuations than conventional laryngoscopy. Also, the lightwand (LW) is believed to provoke a milder pressor response as it does not involve elevation of epiglottis. We decided to evaluate the pressor response to all three devices in normotensive and hypertensive patients.   Methods: We conducted a randomized prospective study consisting of 126 patients posted for surgical procedures under general anesthesia. 63 hypertensive and 63 normotensive patients were randomly assigned to each intubation device: the macintosh laryngoscope (LS), the lightwand (LW), and the intubating laryngeal mask airway (ILMA).The peri-intubation hemodynamic parameters were recorded. Statistical analysis was done with SPSS version 17.0 Inter- and intra-group differences among the hemodynamic variables recorded over time were analyzed by using one-way analysis of variance for repeated measures with bonferroni post-test analysis as appropriate. All quantitative data were expressed as mean±standard deviation (SD). A p-value less than 0.05 was considered statistically significant.Results: All 3 devices (LS, ILMA and LW) are comparable with respect to hemodynamic fluctuations in normotensive patients. However, in hypertensive patients conventional laryngoscopy was associated with greater hemodynamic fluctuations than ILMA or LW. However there was no significant difference in the hemodynamic fluctuations between ILMA and LW.Conclusions: The ILMA and LW may be preferable to LS in hypertensive patients where attenuation of hemodynamic stress response is desired

Ray skin- an emerging unconventional source of leather

Due to the ever-increasing demand for leather products, alternative sources are constantly being explored. Of late, a new trend in using fish skin is gaining momentum, which may become an important event in the development of leather industry. Fish leather has a good tensile strength as any other leather. The process is highly cost-effective, as the raw material generated is generally discarded at fish markets

Green turtle, Chelonia mydas stranded at Malvan, Maharashtra

Sea turtles are found all along the coast of India and five species of sea turtles are reported from Maharashtra viz., Dermochelys coriacea (Leatherback turtle), Eretmochelys imbricata (Hawksbill turtle), Chelonia mydas (Green turtle), Lepidochelys olivacea (Olive ridley) and Caretta caretta (Loggerhead turtle)

Biology of Metapenaeus moyebi (Kishinouye, 1896) and barrier net fishery in Maharashtra waters

Barrier nets down the banks of inshore creeks support localised fisheries along the northern Maharashtra coast. The fishery in Rajpuri creek targeting juveniles of penaeid prawns and fishes is described. Occurrence of penaeid prawn Metapenaeus moyebi and its biology is reported for the first time along the northwest coast of India. It occurs seasonally in small quantity in trawl catches also. The size composition, growth, food and feeding and length-weight relationship of the species are described. The reproductive biology in relation to size at maturity, spawning season and spawning area indicate spawning migrations to the sea. The generation time is six months and the species exhibited two generations annually, with summer and winter cohorts

Seasonal abundance of juvenile threadfin breams from Mumbai waters

A very high catch of juvenile threadfin breams was observed at New Ferry Wharf, Mumbai in March 2007 by shrimp trawlers. The fishing was at about 60-80m depth to the southwest direction of Mumbai (off Ratnagiri) and the fishing duration was for a period of seven days. The total estimated monthly catch of threadfin breams in March '07 was 186.3t. The seasonal abundance of threadfin breams over a period of 3 years from 2004-2006 showed that the maximum catch was during March-April with a smaller peak during September-October

Study of the immediate short term clinical and radiological outcome of intertrochanteric neck of femur fractures treated with primary bipolar hemiarthroplasty in geriatric population in a tertiary care centre

Background: Intertrochanteric fracture in elderly patient is a frequent problem and is becoming more common as the proportion of elderly people in the population increases. Unstable intertrochanteric fracture in the elderly patient is associated with a high rate of mortality as much as 20 percent during the first postoperative year. The treatment of such unstable intertrochanteric fracture is still controversial. So as to allow for earlier postoperative weight-bearing, primary hemiarthroplasty was proposed by some authors. The purpose of this study is to evaluate the functional and clinical outcomes of cemented bipolar arthroplasty as a primary treatment for unstable intertrochanteric fracture in the elderly patient.Methods: It was an observational retrospective plus prospective study design over a period of 18 months in a tertiary care setting with a sample size of 41. Patients fulfilling the inclusion criteria were assessed clinically using Harris hip score and radiologically were operated for bipolar hemiarthroplasty. They were assessed intraoperatively, immediate postoperatively and after 4 weeks for functional outcome using Harris hip score and assessed radiologically. Patients were also be evaluated for intraoperative and postoperative complications if any. The outcome was analysed statistically to comment on functional outcome of bipolar hemiarthroplasty.Results: In our study majority of the patients 70% (29) had excellent and good outcomes at the end of 1 month. Out of the rest 22% more had fair outcome at the end of month. Thus 93% patients had favorable outcomes at the end of 1 month while 7% (3 cases) had poor outcome when measured using Harris hip score.Conclusions: Primary cemented bipolar hemiarthroplasty is a viable option that leads to good functional outcomes and allows early mobilization and weight bearing

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