scholarly journals ASSESSMENT OF TRAFFIC LOAD EVENTS AND STRUCTURAL EFFECTS ON ROAD BRIDGES BASED ON STRAIN MEASUREMENTS

2015 ◽  
Vol 22 (4) ◽  
pp. 457-469 ◽  
Author(s):  
Helder SOUSA ◽  
Bruno J. A. COSTA ◽  
António Abel HENRIQUES ◽  
João BENTO ◽  
Joaquim A. FIGUEIRAS
Keyword(s):  
Probabilistic Approach ◽  
Critical Issue ◽  
Distribution Functions ◽  
Traffic Load ◽  
Scientific Publications ◽  
Railway Bridges ◽  
Traffic Loads ◽  
Extreme Distribution ◽  
Optical Strain ◽  
Observation Period

Several technical and scientific publications have been made available focussing on Bridge Weight-in-Motion (BWIM) concerning railway bridges. On the contrary, BWIM analysis on road bridges are more scarce and therefore, this work intends to provide a contribution by presenting the BWIM analysis performed on two major road bridges in Portugal – Lezíria Bridge and Pinhão Bridge. These bridges are equipped with electric and optical strain gauges, acquisi­tion systems with features that allow high sampling rates. Based on the collected data and focussing on the bridges’ life­time, a probabilistic approach to quantify extreme traffic loads was implemented using extreme distribution functions. The bridges’ behaviour to these extreme traffic loads is numerically evaluated and a comparison with the alarm levels established by the bridge designers is performed. Although the bridge’s safety is not compromised, it was concluded that the representativeness of the observation period is a critical issue and the analysis of this kind of results must be care­fully considered. A comprehensive discussion about this matter is carried out at the end of this work.

Lastannahmen im Brückenbau – Vergleich von Verkehrslasten für Eisenbahnbrücken aus Lastmodellen und Messdaten/Actions on bridges – A comparison of traffic loads for railway bridges from traffic load models and measured data

Bauingenieur ◽  
2016 ◽  
Vol 91 (10) ◽  
pp. 410-416
Author(s):  
Gerhard Lener ◽  
Johannes Schmid
Keyword(s):  
Measured Data ◽  
Traffic Load ◽  
Railway Bridges ◽  
Load Models ◽  
Traffic Loads

Sowohl bei der ursprünglichen Dimensionierung als auch bei allfälligen Sanierungsvorhaben bedingen die Einwirkungen aus Verkehrslasten die Bauteilabmessungen maßgeblich. In vielen Fällen sind ältere Tragwerke nach heutigen Bemessungsrichtlinien deutlich unterdimensioniert, wodurch im Falle von Erweiterungsmaßnahmen zusätzliche Verstärkungsmaßnahmen im Bestand anfallen. Des Weiteren ist die Beurteilung der Restlebensdauer solcher Tragwerke in der Praxis schwierig, da in der Regel keine Informationen hinsichtlich der realen Einwirkungen aus Verkehrslasten vorhanden sind. Durch diesen unbefriedigenden Zustand motiviert, erfolgt in diesem Beitrag eine nähere Untersuchung realer, messtechnisch erfasster Einwirkungen auf Eisenbahnbrücken. Diese bilden die Basis für Vergleiche der Auswirkungen realer Messdaten und normativen Lastmodellen, die rechnerisch an unterschiedlichen Tragsystemen gezeigt werden. Dabei sind die im Vergleich zu den genormten Belastungen doch maßgeblich geringeren Einwirkungen deutlich erkennbar und liefern damit möglicherweise die Antwort auf die Frage, warum einzelne Eisenbahnbrücken nach wie vor funktionieren, obwohl deren rechnerische Lebensdauer bereits erreicht ist. Des Weiteren zeigt sich das daraus resultierende Optimierungspotenzial bei der Aktivierung von Realtragreserven beziehungsweise der deutlich höherer anzusetzender Lebenserwartung bestehender Tragwerke.

scholarly journals Probabilistic Approach to Conditional Probability of Release of Hazardous Materials From Railroad Tank Cars During Accidents

2009 ◽  
Author(s):  
D. Y. Jeong
Keyword(s):  
Sensitivity Analysis ◽  
Conditional Probability ◽  
Impact Velocity ◽  
Probabilistic Sensitivity Analysis ◽  
Probabilistic Approach ◽  
Hazardous Materials ◽  
Relative Effect ◽  
Distribution Functions ◽  
Mean Values ◽  
Effective Collision

This paper describes a probabilistic approach to estimate the conditional probability of release of hazardous materials from railroad tank cars during train accidents. Monte Carlo methods are used in developing a probabilistic model to simulate head impacts. The model is based on the physics of impact in conjunction with assumptions regarding the probability distribution functions of the various factors that affect the loss of lading. These factors include impact velocity, indenter size, tank material, tank diameter, effective collision mass, and tank thickness. Moreover, each factor is treated as a random variable characterized by its assumed distribution function, mean value, and standard deviation (or variance). Reverse engineering is performed to back-calculate the mean values and standard deviations of these random variables that reproduce trends observed in available accident data. The calibrated model is then used to conduct a probabilistic sensitivity analysis to examine the relative effect of these factors on the conditional probability of release. Results from the probabilistic sensitivity analysis indicate that the most significant factors that affect conditional probability of release are impact velocity, effective collision mass, and indenter size.

scholarly journals Optimal User Association Strategy for Large-Scale IoT Sensor Networks with Mobility on Cloud RANs

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4415 ◽  
Author(s):  
Taewoon Kim ◽  
Chanjun Chun ◽  
Wooyeol Choi
Keyword(s):  
Load Balancing ◽  
Large Scale ◽  
Mobile Internet ◽  
Base Stations ◽  
Traffic Load ◽  
User Association ◽  
Network Simulator ◽  
Traffic Loads ◽  
Association Strategy ◽  
Radio Access

In networking systems such as cloud radio access networks (C-RAN) where users receive the connection and data service from short-range, light-weight base stations (BSs), users’ mobility has a significant impact on their association with BSs. Although communicating with the closest BS may yield the most desirable channel conditions, such strategy can lead to certain BSs being over-populated while leaving remaining BSs under-utilized. In addition, mobile users may encounter frequent handovers, which imposes a non-negligible burden on BSs and users. To reduce the handover overhead while balancing the traffic loads between BSs, we propose an optimal user association strategy for a large-scale mobile Internet of Things (IoT) network operating on C-RAN. We begin with formulating an optimal user association scheme focusing only on the task of load balancing. Thereafter, we revise the formulation such that the number of handovers is minimized while keeping BSs well-balanced in terms of the traffic load. To evaluate the performance of the proposed scheme, we implement a discrete-time network simulator. The evaluation results show that the proposed optimal user association strategy can significantly reduce the number of handovers, while outperforming conventional association schemes in terms of load balancing.

An Analysis of Earnings Management: Evidence from Food & Allied Industry of Bangladesh

2017 ◽  
Vol 7 (2) ◽  
pp. 359
Author(s):  
Ajaan Rahman Khan ◽  
Mohsina Akter
Keyword(s):  
Earnings Management ◽  
Probabilistic Approach ◽  
Listed Companies ◽  
Major Portion ◽  
Earnings Manipulation ◽  
Continuous Basis ◽  
One Year ◽  
Observation Period

The objective of the study is to examine the existence of earnings management within listed companies in the food and allied industry of Bangladesh. The renowned Beneish Model has been used to test whether the firms are involved in any sort of earnings manipulation or not. In addition, the tendency of the companies to continuous practice of earnings manipulation has been examined. The study covers a span of 5 years from 2011 to 2015 where the financial figures are tested on the model to find the probability of the companies being a manipulator of earnings. According to Beneish model, companies with higher M-score (manipulation score) are more likely to be a manipulator. The result shows that twelve out of fourteen companies have significantly higher M-score at least for one year during five-year periods. A further study reveals that a major portion of the industry has the tendency of getting into earnings manipulation on a continuous basis. Though the Beneish Model is a probabilistic approach so it is not stoutly conclusive from the test that companies are manipulating earnings or a continuous manipulator within the observation period.

Fracture and Wear as Factors Affecting Stochastic Tool-Life Models and Machining Economics

1977 ◽  
Vol 99 (1) ◽  
pp. 281-286 ◽  
Author(s):  
S. Rossetto ◽  
R. Levi
Keyword(s):  
Failure Modes ◽  
Probabilistic Approach ◽  
Cutting Tools ◽  
Distribution Functions ◽  
Profit Rate ◽  
Tool Failure ◽  
Factors Affecting ◽  
Machining Economics ◽  
Fracture Processes ◽  
Production Conditions

Under production conditions cutting tools often fail under several failure modes, the occurrence of a single one only for a given operation being rather exceptional. In light of this observation a stochastic model is developed, considering as causes of tool failure both wear and fracture processes. Machining economics are then analyzed with a probabilistic approach, deriving distribution functions of profit rate.

scholarly journals ANALYSIS OF THE CURRENT STATE OF METAL RUNWAYS OF RAILWAY BRIDGES

2019 ◽  
pp. 29-40
Author(s):  
S. V. KLUTCHNIK
Keyword(s):  
Probabilistic Approach ◽  
Fatigue Properties ◽  
Loss Of Stability ◽  
Accident Rate ◽  
Railway Bridges ◽  
Artificial Structures ◽  
Current State ◽  
Emergency Events ◽  
The Individual ◽  
Modern Technologies

Purpose. The purpose of this work is to analyze the current state and accident rate of metal span structures of railway bridges. Methodology. Data collection of emergency events on artificial structures. Studying the experience of accident of metal bridges for taking lessons that will help to eliminate the causes that caused them. Findings. The result of this work is the collected data on the state and accident of artificial structures of various sources. Originality. The scientific interest is that with sufficient experience in the construction and operation of artificial structures, the use of modern technologies and materials at this time of bridge crash is not a rare phenomenon. Therefore, the experience of accidents in artificial constructions should be studied, analyzed and used in future decisions. Proving that a probabilistic approach can be used in calculations, as well as the application of norms Eurocodes – this is a possible way to address the question of legitimizing the probabilistic approach. Practical value. Based on the data obtained, it is possible to conclude that the factors of the loss of stability of the individual elements of construction and the fatigue of the materials have not been sufficiently studied, the fatigue properties should be investigated, in order to draw conclusions derived from the experience of bridges in order to help eliminate the causes that caused them.

scholarly journals Optimization of the Observation Period to Improve the Quality of Early Diagnosis of Diseases

Medicina ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 43-53
Author(s):  
V. Ya. Gelman ◽  
Keyword(s):  
Early Diagnosis ◽  
Home Monitoring ◽  
Critical Time ◽  
Practical Experience ◽  
Subsequent Treatment ◽  
Scientific Publications ◽  
Significant Group ◽  
Home Telemonitoring ◽  
Observation Period

The paper considers the possibilities of increasing the efficiency of detecting diseases by reducing the duration of the periods between observations of patients’ health. The methodological basis of the study was the analysis of scientific publications, generalized practical experience and process modelling. The paper proposes indicator – critical time of disease detection, that provides a given treatment efficiency. It is shown that the period of regular clinical examination, which is fixed for a large contingent of patients, does not allow for timely detection of a significant group of diseases. There is a problem of coverage with more frequent observations of patients with possible signs of diseases that have a short critical observation period. As a promising way to solve this problem, the use of home telemonitoring of health status in the delayed time mode is proposed. A method for selecting indicators for additional monitoring has been determined. It has been shown that home monitoring can significantly improve the quality of early diagnosis and the effectiveness of subsequent treatment.

scholarly journals ANALYSIS OF DIAPHRAGM BEHAVIOUR IN COMPOSITE MULTI GIRDER RAILWAY BRIDGES

2004 ◽  
Vol 10 (2) ◽  
pp. 143-150
Author(s):  
Yannick Sieffert ◽  
Gérard Michel ◽  
Didier Martin ◽  
David Keller ◽  
Jean-François Jullien
Keyword(s):  
Bridge Deck ◽  
Element Model ◽  
Longitudinal Distribution ◽  
Railway Bridge ◽  
Railway Bridges ◽  
Traffic Loads ◽  
Concrete Bridge Deck ◽  
Actual Geometry ◽  
Static Failure ◽  
Concrete Deck

This study focuses on mechanical behaviour of diaphragm in composite multigirders railway bridge. The aim is to predict and to compare, with a numerical simulation, the transverse and longitudinal distribution of traffic loads in different girders and in the slab for the cases with and without intermediary diaphragm. A 3‐D finite element model is developed to represent the actual geometry of multigirder bridge. Durability of the concrete bridge deck is directly related to cracking, so a non‐linear constitutive equation is used for the concrete deck. This study focuses on the response of a bridge with and without dipahragm under a UIC and TGV loading. To achieve this aim, a static failure analysis is performed. Our analysis concluded that diaphragm is not necessary, so it seems to be possible to remove the diaphragms.

scholarly journals Improving Energy Efficiency and Minimizing Backhaul Traffic in LTE-A Network with Cooperation and DTX Mechanism

2019 ◽  
Vol 8 (2S11) ◽  
pp. 399-405
Keyword(s):  
Energy Efficiency ◽  
Signal Processing ◽  
Failure Rate ◽  
Energy Efficient ◽  
Acceleration Factor ◽  
Traffic Load ◽  
Sleep Mode ◽  
Transmission Power ◽  
Decision Criteria ◽  
Traffic Loads

The promising approach to enhance energy efficiency (EE) in LTE-A network is to switch underutilized evolved node B (eNB) to sleep mode, but it increases the transmission power to guarantee the coverage under the remaining active eNBs. The increase in transmission power can be reduced by coordinated multi-point (CoMP) technique through eNB cooperation, but this technique consumes extra power due to backhaul traffic and signal processing. This problem can be solved by the proposed energy efficient acceleration factor failure rate (EEAFR) algorithm. The algorithm jointly considers the eNB cooperation and DTX mechanism to minimize the backhaul traffic with less failure rate. Also, to enhance energy efficiency, the proposed algorithm efficiently utilizes the cooperation in all traffic load scenarios based on the decision criteria and DTX mechanism. The results are compared with the existing AFEE and Green CoMP with Backhaul Traffic algorithm. In all the traffic loads EEAFR save 59.8% energy and reduces the network outage which depends on the failure rate of the eNB components

scholarly journals Examining data visualization pitfalls in scientific publications

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Vinh T Nguyen ◽  
Kwanghee Jung ◽  
Vibhuti Gupta
Keyword(s):  
Data Visualization ◽  
Spatial Orientation ◽  
Graphical Representation ◽  
Critical Issue ◽  
Graphical Representations ◽  
Scientific Publications ◽  
Full Force ◽  
Pie Chart ◽  
Fundamental Units

AbstractData visualization blends art and science to convey stories from data via graphical representations. Considering different problems, applications, requirements, and design goals, it is challenging to combine these two components at their full force. While the art component involves creating visually appealing and easily interpreted graphics for users, the science component requires accurate representations of a large amount of input data. With a lack of the science component, visualization cannot serve its role of creating correct representations of the actual data, thus leading to wrong perception, interpretation, and decision. It might be even worse if incorrect visual representations were intentionally produced to deceive the viewers. To address common pitfalls in graphical representations, this paper focuses on identifying and understanding the root causes of misinformation in graphical representations. We reviewed the misleading data visualization examples in the scientific publications collected from indexing databases and then projected them onto the fundamental units of visual communication such as color, shape, size, and spatial orientation. Moreover, a text mining technique was applied to extract practical insights from common visualization pitfalls. Cochran’s Q test and McNemar’s test were conducted to examine if there is any difference in the proportions of common errors among color, shape, size, and spatial orientation. The findings showed that the pie chart is the most misused graphical representation, and size is the most critical issue. It was also observed that there were statistically significant differences in the proportion of errors among color, shape, size, and spatial orientation.

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