A study of the feature‐based digital image stabilization system

Abstract

This article presents a digital image stabilization scheme that uses image processing techniques to compensate for undesirable image jitter due to vehicle or platform vibration to obtain a stabilized image display. The developed digital image stabilization system is based on the image combination approach combined with advanced image selection, feature detection, feature matching and pre‐rotation processing to produce crisp images. Using the Sobel edge detector, we calculate the magnitude of edge response as the judgment criteria for image transformation. To demonstrate the validity of the proposed technique, experimental results are given for some synthetic images.     

Applicability of Doppler weather radar based rainfall data for runoff estimation in Indian watersheds – A case study of Chennai basin

Traditionally, India has been vulnerable to various hazards such as floods, droughts and cyclones. About 8% of the total Indian landmass is prone to cyclones. A number of Doppler weather radars are installed in India and their products are utilized for weather predictions and detection of cyclones approaching the Indian coast. Radar-based hydrological studies in various countries have proven that computation of runoff using radar rainfall data could outperform rain gauge network measurements. There are no reported studies on their utilization for hydrological modelling and/or flood-related studies in Indian river basins. A comparison study between Doppler weather radar (DWR) derived rainfall data and the conventional rain gauge data was carried out with hourly inputs at one of the watersheds of Chennai basin, Tamil Nadu, India using HEC-HMS model. The model calibration and validation were performed by comparing the simulated outflow with the observed daily outflow data. The calibrated model was used to predict runoff from two post-monsoon cyclonic storm events with hourly inputs. It was noticed that the discrepancy in the runoff volume was small, but the difference in the peak flow was substantial. Additionally, there was a variation at the time to peak flow using daily and hourly inputs. The results show that the use of radar data may be optional for runoff volume estimation for the watersheds with sufficient rain gauge density, but highly desirable for peak flow and time to peak estimation. Therefore, the DWR derived rainfall data is a promising input for runoff estimation, especially in urban flood modelling.     

Mechanical performance of biocomposites based on PLA and PHBV reinforced with natural fibres – A comparative study to PP

In the given research paper, the effects of reinforcing polylactid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biopolymers on the mechanical performance were studied. Both PLA and PHBV were compounded with man-made cellulose, jute and abaca fibres. The test bar specimens were processed via injection moulding. Various testing methods, including tensile and impact tests, were used to investigate the composites’ mechanical performance. Scanning electron microscopy was carried out to study the fibre–matrix interphasial adhesion. To determine the fibre-size distribution, optical microscopy was used. Finally, the obtained results were compared to composites on PP basis with the same reinforcing fibres.     

Rational design of high-entropy ceramics based on machine learning – A critical review

High-entropy materials provide a versatile platform for the rational design of novel candidates with exotic performances. Recently, it has been demonstrated that high-entropy ceramics (HECs), depending on their compositions, show great application potential because of their superior structural and functional properties. However, the immense phase space behind HECs significantly hinders the efficient design and exploitation of high-performance HECs through traditional trial-and-error experiments and expensive ab-initio calculations. Machine learning (ML), on the other hand, has become a popular approach to accelerate the discovery of HECs and screen HECs with exceptional properties. In this article, we review the recent progress of ML applications in discovering and designing novel HECs, including carbides, nitrides, borides, and oxides. We thoroughly discuss different ingredients that are involved in ML applications in HECs, including data collection, feature engineering, model refinement, and prediction performance improvement. We finally provide an outlook on the challenges and development directions of future ML models for HEC predictions.     

Does digital imaging decrease patient dose? A pilot study and review of the literature

The potential for decreasing patient dose is one of the main arguments for the justification of the cost of digital imaging equipment. However, the literature review with respect to patient doses using digital imaging modalities, presents conflicting results. During this study, patients' entrance surface doses were measured for three simple radiographic examinations, in European centres equipped with a computed radiography digital system. Results showed that doses between centres varied from 30% for chest LAT to 250% for chest PA examination. With the digital image quality criteria still under discussion, and with the post-processing parameters and/or image documentations varying, any dose comparisons between conventional/digital systems, as well as dose comparisons between different centre using digital units, are difficult. Clinical trials are required in order to define reference levels associated with quality of digital image necessary to address specific clinical requirements.     

Feasibility study of logic circuits with a spin wave bus

We present a feasibility study of logic circuits utilizing spin waves for information transmission and processing. As an alternative approach to the transistor-based architecture, logic circuits with a spin wave bus do not use charge as an information carrier. In this work we describe the general concept of logic circuits with a spin wave bus and illustrate its performance by numerical simulations based on available experimental data. Theoretical estimates and results of numerical simulations on signal attenuation, signal phase velocity, and the minimum spin wave energy required per bit in the spin bus are obtained. The transport parameters are compared with ones for conventional electronic transmission lines. The spin wave bus is not intended to substitute traditional metal interconnects since it has higher signal attenuation and lower signal propagation speed. The potential value of a spin wave bus is, however, an interface between electronic circuits and integrated spintronics circuits. The logic circuits with a spin wave bus allow us to provide wireless read-in and read-out.     

Can the average glandular dose in routine digital mammography screening be reduced? A pilot study using revised image quality criteria

There is a need for tools that in a simple way can be used for the evaluation of image quality related to clinical requirements in mammography. The aim of this work was to adjust the present European image quality criteria to be relevant also for digital mammography images, and to use as simple and as few criteria as possible. A pilot evaluation of the new set of criteria was made with mammograms of 28 women from a General Electric Senographe 2000D full-field digital mammography system. One breast was exposed using the standard automatic exposure mode, the other using about half of that absorbed dose. Three experienced radiologists evaluated the images using visual grading analysis technique. The results indicate that the new quality criteria can be used for the evaluation of image quality related to clinical requirements in digital mammography in a simple way. The results also suggest that absorbed doses for the mammography system used may be substantially reduced.     

Modelling and comparative study of viscoelastic laminated composite beam – an operator based finite element approach

Mechanics of Time-Dependent Materials - Finite element formulation of damped laminated composite beam considering both Euler-Bernoulli and Timoshenko beam theory is proposed based on Equivalent...     

A pilot study of three-stage biological–chemical treatment of landfill leachate applying continuous ferric sludge reuse in Fenton-like process

This pilot study describes a three-stage continuous process for treating landfill leachate containing significant concentrations of recalcitrant organic substances. The proposed technological scheme consisted of an activated sludge pre-treatment combined with a Fenton-like process enhanced by continuous sludge reuse and followed by an activated sludge post-oxidation. Biological pre-treatment removed >99, 86, >99, 83 and 86 % of BOD₇, COD, NH₄ ⁺–N, phenols and the sum of lignin and tannins, respectively. Operational conditions in the ferric sludge-catalysed Fenton-like process stage were carefully adjusted in order to maintain the efficacy and practicability of combined treatment scheme. Although the application of ferric sludge as a catalyst in the Fenton-like oxidation reduced COD removal efficiency by 32 % as compared to the conventional Fenton process, lower process efficiency was compensated by reducing the water exchange ratio to 50 % without increasing the consumption of reagents. Moreover, an intermittent addition (added to every second treatment cycle) of fresh ferrous iron catalyst at a H₂O₂/Fe²⁺ w/w ratio of 20/1 increased the BOD₇/COD ratio from 0.04 to 0.32 and resulted in 60 % COD removal. A cyclic addition (added to every treatment cycle) of the same amount of catalyst increased the BOD₇/COD ratio from 0.09 to 0.32, and a 10 % higher COD removal efficiency as compared to intermittent catalyst addition was achieved. Finally, biological post-treatment of the leachate resulted in more than 95 % removal of each measured parameter. Overall, the combined technological scheme with continuous ferric sludge reuse in the Fenton-like stage proved promising alternative for landfill leachate treatment.     

Liquation cracking of Al-6.3 Cu alloy propellant storage tank – A case study

Rings and sheets of aluminium alloy AA 2219 of Al–Cu series are being used for the fabrication of propellant storage tank. Under development phase, one such tank failed in the course of qualification. Detailed metallurgical analyses were carried out on this failed tank, which revealed the presence of large number of incipiently melted & solidified particles as a result of welding/repair welding, along the grain boundaries and also within the grains nearer to weld fusion line. This has resulted in the formation of continuous film along the grain boundaries of already coarser grains of the ring. Such film which formed by liquation at the weld fusion line/HAZ, under the influence of residual stresses due to welding under fixture constraints, especially near the weld repair region, initiated the crack formation. The crack once initiated, found easy propagation through film along the grain boundaries (GB). Electron probe micro analysis (EPMA) of these particles confirmed the film as eutectic, low-melting compound and their non-uniform distribution.This paper highlights the investigations carried out on the failed tank.     

A study of bicyclist kinematics and injuries based on reconstruction of passenger car–bicycle accident in China

Like pedestrians, bicyclists are vulnerable road users, representing a population with a high risk of fatal and severe injuries in traffic accidents as they are unprotected during vehicle collisions. The objective of this study is to investigate the kinematics response of bicyclists and the correlation of the injury severity with vehicle impact speed. Twenty-four car–bicyclist cases with detailed information were selected for accident reconstruction using mathematical models, which was implemented in the MADYMO program. The dynamic response of bicyclists in the typical impact configuration and the correlation of head impact conditions were analyzed and discussed with respect to the head impact speed, time of head impact and impact angle of bicyclists to vehicle impact speed. Furthermore, the injury distribution of bicyclists and the risk of head injuries and fractures of lower limbs were investigated in terms of vehicle impact speed. The results indicate that wrap-around distance (WAD), head impact speed, time of head impact, head impact angle, and throw-out distance (TOD) of the bicyclists have a strong relationship with vehicle impact speed. The vehicle impact speed corresponding to a 50% probability of head AIS 2+ injuries, head AIS 3+ injuries, and lower limb fracture risk for bicyclists is 53.8 km/h, 58.9 km/h, and 41.2 km/h, respectively. A higher vehicle impact speed produces a higher injury risk to bicyclist. The results could provide background knowledge for the establishment or modification of pedestrian regulations considering bicyclist protection as well as being helpful for developing safety measures and protection devices for bicyclists.     

Obsolescence – A review of the literature

Technology progress and fierce competitiveness between manufacturers creates intense pressues to innovatively develop and sell new products. These products could be household or industrial items, such as telephones, computers, machines, robots, unmanned aerial vehicle (UAV), motors, industrial processes, electronic devices, tools, and spare parts in general. The technological progress implies the use of the word “obsolescence.” The new products have higher performance metrics compared to the older units, such as reliability, resilience, memory capacity, improved material, precision, artificial intelligence, lower energy consumption, ergonomics, and safety. Therefore, obsolescence became a paradox in our daily life and industry. This paper presents a literature review of the main published works on obsolescence (1976–2020). Its typologies, consequences and replacement strategies are illustrated.     

A Big-Data-based platform of workers’ behavior: Observations from the field

Behavior-Based Safety (BBS) has been used in construction to observe, analyze and modify workers’ behavior. However, studies have identified that BBS has several limitations, which have hindered its effective implementation. To mitigate the negative impact of BBS, this paper uses a case study approach to develop a Big-Data-based platform to classify, collect and store data about workers’ unsafe behavior that is derived from a metro construction project. In developing the platform, three processes were undertaken: (1) a behavioral risk knowledge base was established; (2) images reflecting workers’ unsafe behavior were collected from intelligent video surveillance and mobile application; and (3) images with semantic information were stored via a Hadoop Distributed File System (HDFS). The platform was implemented during the construction of the metro-system and it is demonstrated that it can effectively analyze semantic information contained in images, automatically extract workers’ unsafe behavior and quickly retrieve on HDFS as well. The research presented in this paper can enable construction organizations with the ability to visualize unsafe acts in real-time and further identify patterns of behavior that can jeopardize safety outcomes.     

A validation study of “LEXIMAPPE”

Clusters of normalized title-words in two sets of patent data in the food-sector (from 1985 and 1989, respectively) are analyzed in terms of their underlying document and word structures. The clusters were generated by using the system LEXIMAPPE of the Paris School of Mines. Both input and output data were kindly made available for validation purposes. Analysis of the data shows that the centrality and the density of the clusters produced by LEXIMAPPE are primarily dependent on the number of word occurrences in the corresponding parts of the input matrix. While the clusters are kept approximately equal in terms of the number of words (with a maximum of 10), they vary widely in terms of the number of word occurrences in the underlying document sets. Centrality and density vary correspondingly. The contribution of the smallest cluster to the reduction of uncertainty in the prediction of the document structure is even smaller than that of 77 (other) single words. In the dynamic analysis, I found significant stability where LEXIMAPPE indicated major changes. However, like every clustering algorithm LEXIMAPPE is based on specific assumptions which may lead to specific results that cannot be simulated by using other methods. Researchers who base their results on LEXIMAPPE should be aware of the peculiarities specific to this system.     

Safety impacts of platform tram stops on pedestrians in mixed traffic operation: A comparison group before–after crash study

Tram stops in mixed traffic environments present a variety of safety, accessibility and transport efficiency challenges. In Melbourne, Australia the hundred year-old electric tram system is progressively being modernized to improve passenger accessibility. Platform stops, incorporating raised platforms for level entry into low floor trams, are being retro-fitted system-wide to replace older design stops. The aim of this study was to investigate the safety impacts of platform stops over older design stops (i.e. Melbourne safety zone tram stops) on pedestrians in the context of mixed traffic tram operation in Melbourne, using an advanced before–after crash analysis approach, the comparison group (CG) method. The CG method evaluates safety impacts by taking into account the general trends in safety and the unobserved factors at treatment and comparison sites that can alter the outcomes of a simple before–after analysis. The results showed that pedestrian-involved all injury crashes reduced by 43% after platform stop installation. This paper also explores a concern that the conventional CG method might underestimate safety impacts as a result of large differences in passenger stop use between treatment and comparison sites, suggesting differences in crash risk exposure. To adjust for this, a modified analysis explored crash rates (crash counts per 10,000 stop passengers) for each site. The adjusted results suggested greater reductions in pedestrian-involved crashes after platform stop installation: an 81% reduction in pedestrian-involved all injury crashes and 86% reduction in pedestrian-involved FSI crashes, both are significant at the 95% level. Overall, the results suggest that platform stops have considerable safety benefits for pedestrians. Implications for policy and areas for future research are explored.     

Benefits of internal curing on service life and life-cycle cost of high-performance concrete bridge decks – A case study

This paper investigates the impact of internal curing on the service life of high-performance concrete (HPC) bridge decks by using analytical models to predict the times to onset of corrosion, onset of corrosion-induced damage, and failure of decks. Three bridge deck design options were compared: (i) normal concrete deck; (ii) HPC deck with supplementary cementing materials (SCM); and (iii) HPC deck with SCM and internal curing. It was found that the use of internal curing can extend the service life of high-performance concrete bridge decks by more than 20 years, which is mainly due to a significant reduction in the rate of penetration of chlorides in concrete as a result of reduced early-age shrinkage cracking and reduced chloride diffusion. Compared to normal concrete, HPC with SCM and internal curing was predicted to add more than 40 years to the service life of bridge decks in severe environmental conditions. Life-cycle cost reductions of 40% and 63% were estimated when conventional HPC and internally-cured HPC were used in bridge decks instead of normal concrete, respectively, despite the fact that the in-place unit cost of internally-cured HPC can be 4% higher than that of conventionally-cured HPC, which in turn can be up to 33% higher than that of normal concrete. This is due to a longer service life and less frequent maintenance activities offered by low-permeability HPC bridge decks.     

A rear-end collision risk assessment model based on drivers’ collision avoidance process under influences of cell phone use and gender—A driving simulator based study

Driver’s collision avoidance performance has a direct link to the collision risk and crash severity. Previous studies demonstrated that the distracted driving, such as using a cell phone while driving, disrupted the driver’s performance on road. This study aimed to investigate the manner and extent to which cell phone use and driver’s gender affected driving performance and collision risk in a rear-end collision avoidance process. Forty-two licensed drivers completed the driving simulation experiment in three phone use conditions: no phone use, hands-free, and hand-held, in which the drivers drove in a car-following situation with potential rear-end collision risks caused by the leading vehicle’s sudden deceleration. Based on the experiment data, a rear-end collision risk assessment model was developed to assess the influence of cell phone use and driver’s gender. The cell phone use and driver’s gender were found to be significant factors that affected the braking performances in the rear-end collision avoidance process, including the brake reaction time, the deceleration adjusting time and the maximum deceleration rate. The minimum headway distance between the leading vehicle and the simulator during the rear-end collision avoidance process was the final output variable, which could be used to measure the rear-end collision risk and judge whether a collision occurred. The results showed that although cell phone use drivers took some compensatory behaviors in the collision avoidance process to reduce the mental workload, the collision risk in cell phone use conditions was still higher than that without the phone use. More importantly, the results proved that the hands-free condition did not eliminate the safety problem associated with distracted driving because it impaired the driving performance in the same way as much as the use of hand-held phones. In addition, the gender effect indicated that although female drivers had longer reaction time than male drivers in critical situation, they were more quickly in braking with larger maximum deceleration rate, and they tended to keep a larger safety margin with the leading vehicle compared to male drivers. The findings shed some light on the further development of advanced collision avoidance technologies and the targeted intervention strategies about cell phone use while driving.     

Magnetism of rough overlayers – an augmented space recursive study

The use of the augmented space recursion (ASR) coupled with tight-binding linearized muffin tin orbital method as an ideal methodology for the study of electronic and magnetic structures of rough surfaces, interfaces and overlayers is proposed here. The present method deals satisfactorily with roughness, short-ranged clustering effects and interdiffusion. We present here results on magnetism of Fe overlayer on Cu, Ag and Au substrates.     

Drivers’ phone use at red traffic lights: A roadside observation study comparing calls and visual–manual interactions

Phone use while driving has become one of the priority issues in road safety, given that it may lead to decreased situation awareness and deteriorated driving performance. It has been suggested that drivers can regulate their exposure to secondary tasks and seek for compatibility of phone use and driving. Phone use strategies include the choice of driving situations with low demands and interruptions of the interaction when the context changes. Traffic light situations at urban intersections imply both a temptation to use the phone while waiting at the red traffic light and a potential threat due to the incompatibility of phone use and driving when the traffic light turns green. These two situations were targeted in a roadside observation study, with the aim to investigate the existence of a phone use strategy at the red traffic light and to test its effectiveness. N = 124 phone users and a corresponding control group of non-users were observed. Strategic phone use behaviour was detected for visual–manual interactions, which are more likely to be initiated at the red traffic light and tend to be stopped before the vehicle moves off, while calls are less likely to be limited to the red traffic light situation. As an indicator of impaired situation awareness, delayed start was associated to phone use and in particular to visual–manual interactions, whether phone use was interrupted before moving off or not. Traffic light situations do not seem to allow effective application of phone use strategies, although drivers attempt to do so for the most demanding phone use mode. The underlying factors of phone use need to be studied so as to reduce the temptation of phone use and facilitate exposure regulation strategies.