Em Approach on Influence Measures in Competing Risks Via Proportional Hazard Regression Model

In a conventional competing risk s model, the time to failure of a particular experimental unit might be censored and the cause of failure can be known or unknown. In this thesis the analysis of this particular model was based on the cause-specific hazard of Cox model. The Expectation Maximization (EM) was considered to obtain the estimate of the parameters. These estimates were then compared to the Newton-Raphson iteration method. A generated data where the failure times were taken as exponentially distributed was used to further compare these two methods of estimation. From the simulation study for this particular case, we can conclude that the EM algorithm proved to be more superior in terms of mean value of parameter estimates, bias and root mean square error. To detect irregularities and peculiarities in the data set, the residuals, Cook distance and the likelihood distance were computed. Unlike the residuals, the perturbation method of Cook's distance and the likelihood distance were effective in the detection of observations that have influenced on the parameter estimates. We considered both the EM approach and the ordinary maximum likelihood estimation (MLE) approach in the computation of the influence measurements. For the ultimate results of influence measurements we utilized the approach of the one step . The EM one-step and the maximum likelihood (ML) one-step gave conclusions that are analogous to the full iteration distance measurements. In comparison, it was found that EM one-step gave better results than the ML one step with respect to the value of Cook's distance and likelihood distance. It was also found that Cook's distance i s better than the likelihood distance with respect to the number of observations detected

Analysis of the sign regressor least mean fourth adaptive algorithm

A novel algorithm, called the signed regressor least mean fourth (SRLMF) adaptive algorithm, that reduces the computational cost and complexity while maintaining good performance is presented. Expressions are derived for the steady-state excess-mean-square error (EMSE) of the SRLMF algorithm in a stationary environment. A sufficient condition for the convergence in the mean of the SRLMF algorithm is derived. Also, expressions are obtained for the tracking EMSE of the SRLMF algorithm in a nonstationary environment, and consequently an optimum value of the step-size is obtained. Moreover, the weighted variance relation has been extended in order to derive expressions for the mean-square error (MSE) and the mean-square deviation (MSD) of the proposed algorithm during the transient phase. Computer simulations are carried out to corroborate the theoretical findings. It is shown that there is a good match between the theoretical and simulated results. It is also shown that the SRLMF algorithm has no performance degradation when compared with the least mean fourth (LMF) algorithm. The results in this study emphasize the usefulness of this algorithm in applications requiring reduced implementation costs for which the LMF algorithm is too complex

Quantitative infrared thermography resolved leakage current problem in cathodic protection system

Leakage current problem can happen in Cathodic Protection (CP) system installation. It could affect the performance of underground facilities such as piping, building structure, and earthing system. Worse can happen is rapid corrosion where disturbance to plant operation plus expensive maintenance cost. Occasionally, if it seems, tracing its root cause could be tedious. The traditional method called line current measurement is still valid effective. It involves isolating one by one of the affected underground structures. The recent methods are Close Interval Potential Survey and Pipeline Current Mapper were better and faster. On top of the mentioned method, there is a need to enhance further by synthesizing with the latest visual methods. Therefore, this paper describes research works on Infrared Thermography Quantitative (IRTQ) method as resolution of leakage current problem in CP system. The scope of study merely focuses on tracing the root cause of leakage current occurring at the CP system lube base oil plant. The results of experiment adherence to the hypothesis drawn. Consequently, res

Impact of laparoscopic versus open surgery on hospital costs for colon cancer: a population-based retrospective cohort study

OBJECTIVE: Laparoscopy is increasingly being used as an alternative to open surgery in the treatment of patients with colon cancer. The study objective is to estimate the difference in hospital costs between laparoscopic and open colon cancer surgery. DESIGN: Population-based retrospective cohort study. SETTINGS: All acute hospitals of the National Health System in England. POPULATION: A total of 55 358 patients aged 30 and over with a primary diagnosis of colon cancer admitted for planned (elective) open or laparoscopic major resection between April 2006 and March 2013. PRIMARY OUTCOMES: Inpatient hospital costs during index admission and after 30 and 90 days following the index admission. RESULTS: Propensity score matching was used to create comparable exposed and control groups. The hospital cost of an index admission was estimated to be £1933 (95% CI 1834 to 2027; p<0.01) lower among patients who underwent laparoscopic resection. After including the first unplanned readmission following index admission, laparoscopy was £2107 (95% CI 2000 to 2215; p<0.01) less expensive at 30 days and £2202 (95% CI 2092 to 2316; p<0.01) less expensive at 90 days. The difference in cost was explained by shorter hospital stay and lower readmission rates in patients undergoing minimal access surgery. The use of laparoscopic colon cancer surgery increased 4-fold between 2006 and 2012 resulting in a total cost saving in excess of £29.3 million for the National Health Service (NHS). CONCLUSIONS: Laparoscopy is associated with lower hospital costs than open surgery in elective patients with colon cancer suitable for both interventions

Regression analysis of masked competing risks data under cumulative incidence function framework

In the studies that involve competing risks, somehow, masking issues might arise. That is, the cause of failure for some subjects is only known as a subset of possible causes. In this study, a Bayesian analysis is developed to assess the effect of risks factor on the Cumulative Incidence Function (CIF) by adopting the proportional subdistribution hazard model. Simulation is conducted to evaluate the performance of the proposed model and it shows that the model is feasible for the possible applications

Kandungan Logam Berat Timbal (Pb) Dan Tembaga (Cu) Pada Karang Pocillopora Damicornis Di Perairan Taman Nasional Karimunjawa

Human activities in the Karimunjawa National Park increase water pollution, including heavy metals such as lead (Pb) and copper (Cu). The existence of heavy metals in sea waters can not be degraded, but it can be absorbed and accumulated in the body of organisms, including coral, Pocillopora damicornis. Given the existence of coral P. damicornis as sessile organism which are able to absorb lead (Pb) and copper (Cu) from the water, therefore, it is necessary to conduct research on heavy metals content in the coral. The purpose of this study was to determine the content of heavy metals lead (Pb) and copper (Cu) on the coral P. damicornis taken from several locations around the Karimunjawa National Park. The results of the study showed that heavy metals content in the water was not detected. While the highest Pb and Cu were found in the coral collected from Burung Island that was equal to 0.00405 ppm and 0.01121 ppm, respectively. The lowest Pb substance were found in the coral collected from Kemojan canal i.e. 0.00143 ppm. Sample collected from Indonoor, Kemojan canal and Karimunjawa port did not contain Cu substance. Based on Pb and Cu data contained in the coral and water samples Minister of Environment Decree No.51st, 2004, it could be concluded that the conditions of Karimunjawa National Park was still in the stage of no contamination

Management and Complications of Arnold Chiari Hydrocephalus at Tertiary Health Care Center

Objective:&nbsp;to investigate the role of CT and MRI in diagnosis of Arnold chiari malformation of hydrocephalus and its treatment with VP shunt along with complications. Study Design:&nbsp;Prospective study Place and duration:&nbsp;Department of Neurosurgery, DG Khan Medical College from May 4, 2018 to May 4, 2019. Methodology:&nbsp;Fifty patients of congenital hydrocephalus who were not treated previously were selected. Detailed history about disease and clinical examination of patients was performed. Follow ups were done at neurosurgery OPD. SPSS software for data analysis was used and mean ± SD, frequency and percentages were calculated for variables. P value ≤0.05 was considered as significant. Results:&nbsp;Treatment in case of congenital hydrocephalus as VP shunt, intra-aneurysmal coiling, excision of meningomyelocele with VP shunt and suboccipital craniectomy + upper cervical laminectomy (scucl) were observed as 10%, 6%, 8% and 8% respectively.&nbsp; Twelve percent of patients were not treated. Conclusion:&nbsp;CT and MRI are the main diagnostic tools for diagnosis of Arnold chiari malformation and VP shunt is the treatment of choice. Among complications of VP shunt infection of shunt and shunt block are the main complications

Investigation of multi-phase tubular permanent magnet linear generator for wave energy converters

In this article, an investigation into different magnetization topologies for a long stator tubular permanent magnet linear generator is performed through a comparison based on the cogging force disturbance, the power output, and the cost of the raw materials of the machines. The results obtained from finite element analysis simulation are compared with an existing linear generator described in [1]. To ensure accurate results, the generator developed in [1] is built with 3D CAD and simulated using the finite-element method, and the obtained results are verified with the source.The PRIMaRE project