Computer vision-based method for concrete crack detection

© 2016 IEEE. This paper presents a computer vision-based method to automatically detect concrete cracks. We focus on images containing the concrete: background and crack, where the background is the major mode of the gray-scale histogram. Therefore, we address the detection problem of potential concrete cracks by dealing with histogram thresholding to extract regions of interests from the background. We first employ line emphasis and moving average filters to remove noise from concrete surface images obtained from an inspection robot. The developed algorithm is then applied for automatic detection of significant peaks from the gray-scale histogram of the smoothed image. The biggest peak and its corresponding valley(s) are consequently identified to calculate the threshold value for image binarization. The effectiveness of our proposed method was successfully evaluated on various test images, where cracks could be identified without the requirement of some heuristic reasoning

The financial protection effect of Ghana National Health Insurance Scheme: evidence from a study in two rural districts

<p>Abstract</p> <p>Background</p> <p>One of the key functions of health insurance is to provide financial protection against high costs of health care, yet evidence of such protection from developing countries has been inconsistent. The current study uses the case of Ghana to contribute to the evidence pool about insurance's financial protection effects. It evaluates the impact of the country's National Health Insurance Scheme on households' out-of-pocket spending and catastrophic health expenditure.</p> <p>Methods</p> <p>We use data from a household survey conducted in two rural districts, Nkoranza and Offinso, in 2007, two years after the initiation of the Ghana National Health Insurance Scheme. To address the skewness of health expenditure data, the absolute amount of out-of-pocket spending is estimated using a two-part model. We also conduct a probit estimate of the likelihood of catastrophic health expenditures, defined at different thresholds relative to household income and non-food consumption expenditure. The analysis controls for chronic and self-assessed health conditions, which typically drive adverse selection in insurance.</p> <p>Results</p> <p>At the time of the survey, insurance coverage was 35 percent. Although the benefit package of insurance is generous, insured people still incurred out-of-pocket payment for care from informal sources and for uncovered drugs and tests at health facilities. Nevertheless, they paid significantly less than the uninsured. Insurance has been shown to have a protective effect against the financial burden of health care, reducing significantly the likelihood of incurring catastrophic payment. The effect is particularly remarkable among the poorest quintile of the sample.</p> <p>Conclusions</p> <p>Findings from this study confirm the positive financial protection effect of health insurance in Ghana. The effect is stronger among the poor group than among general population. The results are encouraging for many low income countries who are considering a similar policy to expand social health insurance. Ghana's experience also shows that instituting insurance by itself is not adequate to remove fully the out-of-pocket payment for health. Further works are needed to address the supply side's incentives and quality of care, so that the insured can enjoy the full benefits of insurance.</p

Angle-Encoded Swarm Optimization for UAV Formation Path Planning

© 2018 IEEE. This paper presents a novel and feasible path planning technique for a group of unmanned aerial vehicles (DAVs) conducting surface inspection of infrastructure. The ultimate goal is to minimise the travel distance of DAVs while simultaneously avoid obstacles, and maintain altitude constraints as well as the shape of the UAV formation. A multiple-objective optimisation algorithm, called the Angle-encoded Particle Swarm Optimization (θ- PSO) algorithm, is proposed to accelerate the swarm convergence with angular velocity and position being used for the location of particles. The whole formation is modelled as a virtual rigid body and controlled to maintain a desired geometric shape among the paths created while the centroid of the group follows a pre-determined trajectory. Based on the testbed of 3DR Solo drones equipped with a proprietary Mission Planner, and the Internet-of- Things (loT) for multi-directional transmission and reception of data between the DAV s, extensive experiments have been conducted for triangular formation maintenance along a monorail bridge. The results obtained confirm the feasibility and effectiveness of the proposed approach

The spectra of selected functional gastrointestinal disorders in Sudanese university students according to the Rome III criteria

Background: The prevalence of functional gastrointestinal disorders  (FGIDs) including functional dyspepsia (FD), irritable bowel syndrome (IBS) and functional constipation (FC) was not studied in Sudan.Objectives: The aim of this study is to estimate prevalence of these disorders in Sudanese university students using Rome III criteria.Materials and Methods: A cross-sectional descriptive study was conducted among medical students in Omdurman Islamic University during the period from January to June 2012. The selected volunteers responded to a self-reported questionnaire based on Rome III criteria.Results: A total of 348 subjects were studied. Male: Female ratio was 0.6: 1. Prevalence of FD, IBS and FC were 21.6%, 12.9% and 10.3% respectively. IBS was more prevalent in females (16.4%) compared to males (7%). The most prevalent symptoms were postprandial fullness (74.1%), straining during .25% of defecation (43.9%) and lumpy or hard stools in .25% of defecations (37%).Conclusion: Functional gastrointestinal disorders are common in university students. Further studies are needed to characterize the epidemiology of FGIDs in Sudan.Key words: Functional gastrointestinal disorders, dyspepsia, irritable bowel syndrome, constipation, Sudan

Enhanced discrete particle swarm optimization path planning for UAV vision-based surface inspection

© 2017 In built infrastructure monitoring, an efficient path planning algorithm is essential for robotic inspection of large surfaces using computer vision. In this work, we first formulate the inspection path planning problem as an extended travelling salesman problem (TSP) in which both the coverage and obstacle avoidance were taken into account. An enhanced discrete particle swarm optimization (DPSO) algorithm is then proposed to solve the TSP, with performance improvement by using deterministic initialization, random mutation, and edge exchange. Finally, we take advantage of parallel computing to implement the DPSO in a GPU-based framework so that the computation time can be significantly reduced while keeping the hardware requirement unchanged. To show the effectiveness of the proposed algorithm, experimental results are included for datasets obtained from UAV inspection of an office building and a bridge

Pattern of Endoscopic Findings of Upper Gastrointestinal Tract in Omdurman Teaching Hospital, Sudan

Background: The pattern of endoscopic findings of upper gastrointestinal tract (UGT) including gastro esophageal reflux (GERD), peptic ulcer diseases (PU), and upper gastrointestinal malignancies was not studied recently in Sudan.Objectives: The aim of this study is to know the pattern of endoscopic findings of upper gastrointestinal tract.Materials and Methods: This is a cross-sectional descriptive study which was conducted during the period from March to September 2013, at endoscopy unit in Omdurman Teaching Hospital. All patients referred for upper gastrointestinal endoscopy were included in the study.Results: A total of 390 subjects was enrolled in the study.56.4% were females; the male to female ratio was 1.3:1, their ages ranged from 11 to 80 years old with a mean age of 50.2 years. The most common endoscopic findings in the study group was Gastritis 54.9% followed by esophagitis 42%, peptic ulcer diseases 21%, esophageal varices 13.8% and upper gastrointestinal tumors (esophageal and gastric) 13.2 %. Normal findings were found in 3% of all patients in the study group.Conclusion: Upper gastrointestinal disorders are more common in Sudan compared to other countries. Esophageal varices and upper gastrointestinal malignancies are increasing compared to previous studies. Further studies are required to characterize abnormalities of upper gastrointestinal tract.Key words: Upper gastro-intestinal endoscopy, Gastritis, Esophagitis, Peptic ulcer, Sudan

Fuzzy sliding mode control of an offshore container crane

© 2017 A fuzzy sliding mode control strategy for offshore container cranes is investigated in this study. The offshore operations of loading and unloading containers are performed between a mega container ship, called the mother ship, and a smaller ship, called the mobile harbor (MH), which is equipped with a container crane. The MH is used to transfer the containers, in the open sea, and deliver them to a conventional stevedoring port, thereby minimizing the port congestion and also eliminating the need of expanding outwards. The control objective during the loading and unloading process is to keep the payload in a desired tolerance in harsh conditions of the MH motion. The proposed control strategy combines a fuzzy sliding mode control law and a prediction algorithm based on Kalman filtering for the MH roll angle. Here, the sliding surface is designed to incorporate the desired trolley trajectory while suppressing the sway motion of the payload. To improve the control performance, the discontinuous gain of the sliding control is adjusted with fuzzy logic tuning schemes with respect to the sliding function and its rate of change. Chattering is further reduced by a saturation function. Simulation and experimental results are provided to verify the effectiveness of the proposed control system for offshore container cranes

Crack detection using enhanced thresholding on UAV based collected images

© 2018 Australasian Robotics and Automation Association. All rights reserved. This paper proposes a thresholding approach for crack detection in an unmanned aerial vehicle (UAV) based infrastructure inspection system. The proposed algorithm performs recursively on the intensity histogram of UAV-taken images to exploit their crack-pixels appearing at the low intensity interval. A quantified criterion of interclass contrast is proposed and employed as an object cost and stop condition for the recursive process. Experiments on different datasets show that our algorithm outperforms different segmentation approaches to accurately extract crack features of some commercial buildings

Quantum-mechanical analysis of effect of alloying elements on ε-martensite start temperature of steels

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Automatic interpretation of unordered point cloud data for UAV navigation in construction

© 2016 IEEE. The objective of this work is to develop a data processing system that can automatically generate waypoints for navigation of an unmanned aerial vehicle (UAV) to inspect surfaces of structures like buildings and bridges. The input includes data recorded by two 2D laser scanners, orthogonally mounted on the UAV, and an inertial measurement unit (IMU). To achieve the goal, algorithms are developed to process the data collected. They are separated into three major groups: (i) the data registration and filtering to generate a 3D model of the structure and control the density of point clouds for data completeness enhancement; (ii) the surface and obstacle detection to assist the UAV in monitoring tasks; and (iii) the waypoint generation to set the flight path. Experiments on different data sets show that the developed system is able to reconstruct a 3D point cloud of the structure, extract its surfaces and objects, and generate waypoints for the UAV to accomplish inspection tasks