scholarly journals A Probabilistic Assessment Model for Train-Bridge Systems: Special Attention on Track Irregularities

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Dejun Liu ◽  
Lifeng Xin ◽  
Xiaozhen Li ◽  
Jiaxin Zhang
Keyword(s):  
Stochastic Analysis ◽  
Failure Modes ◽  
High Efficiency ◽  
Coupled Model ◽  
Assessment Model ◽  
Ergodic Properties ◽  
Probability Density Evolution Method ◽  
Proposed Model ◽  
Random Track Irregularities ◽  
Track Irregularities

In this paper, a probabilistic model devoted to investigating the dynamic behaviors of train-bridge systems subjected to random track irregularities is presented, in which a train-ballasted track-bridge coupled model with nonlinear wheel-rail contacts is introduced, and then a new approach for simulating a random field of track irregularities is developed; moreover, the probability density evolution method is used to describe the probability transmission from excitation inputs to response outputs; finally, extended analysis from three aspects, that is, stochastic analysis, reliability analysis, and correlation analysis, are conducted on the evaluation and application of the proposed model. Besides, compared to the Monte Carlo method, the high efficiency and the accuracy of this proposed model are validated. Numerical studies show that the ergodic properties of track irregularities on spectra, amplitudes, wavelengths, and phases should be taken into account in stochastic analysis of train-bridge interactions. Since the main contributive factors concerning different dynamic indices are rather different, different failure modes possess no obvious or only weak correlations from the probabilistic perspective, and the first-order reliability theory is suitable in achieving the system reliability.

Higher-Order Thinking Skills (HOTS)-based Formative Assessment: A Proposed Model for Language Learning Assessment

2020 ◽  
Vol 9 (2) ◽  
pp. 115
Author(s):  
Wiyaka Wiyaka ◽  
Entika Fani Prastikawati ◽  
AB Prabowo Kusumo Adi
Keyword(s):  
Formative Assessment ◽  
Language Learning ◽  
Higher Order Thinking ◽  
Thinking Skills ◽  
Higher Order ◽  
Formative Assessments ◽  
Assessment Model ◽  
Higher Order Thinking Skills ◽  
Learning Assessments ◽  
Proposed Model

<div><p class="StyleABSTRAKenCambria">The integration of higher-order thinking skills (HOTS) in language learning assessments has become a crucial issue in 21st-century learning. However, not many teachers are aware of the need to incorporate HOTS in assessments due to their insufficient knowledge and the absence of good examples. Further, there is not much research and literature on HOTS-based formative assessment that can be used as references. This research aims to fill the existing gap by providing a model of higher-order thinking skills (HOTS)-based formative assessments for English learning, especially in junior high schools. By employing research and development design, this research describes the validation of the assessment model. The proposed model of assessment may be used as a prototype for assessing language learning.</p></div><p> </p>

scholarly journals Evaluation of water loss in transit and surface runoff in a Brazilian semi-arid basin

2020 ◽  
Vol 15 (4) ◽  
pp. 1
Author(s):  
Cristian Epifanio Toledo ◽  
João Carlos Mohn Nogueira ◽  
Alexandre De Amorim Camargo
Keyword(s):  
Water Loss ◽  
Surface Runoff ◽  
High Efficiency ◽  
Heterogeneous Environments ◽  
Runoff Coefficient ◽  
Water Losses ◽  
Proposed Model ◽  
Reservoir Basin ◽  
In Transit ◽  
Semi Arid

The objective of this work was to propose and evaluate a model to estimate transit water losses and surface runoff in a Brazilian semi-arid basin, fundamental components in the hydrological studies of the region, such as in the verification of hydrological connectivity. The study area was the Orós Reservoir Basin, located in the state of Ceará. The modeling of transit water loss and surface runoff were developed based on the work of Araújo and Ribeiro (1996) and Peter et al. (2014). In the proposed model, the parameter of loss in transit (k) was estimated at 0.027 km-1 for a section of the river basin, and when simulated for other stretches it provided good flow results at the end of the stretch, obtaining an NSE of 82%. The value of the runoff coefficient was estimated at 3% and when evaluating a spatial variation of this coefficient in the basin, the values varied from 2% to 12%, and the use of specialized runoff coefficient (RC) values promoted a higher NSE in the discharge simulation in the basin. It is concluded that the proposed model to estimate transit water losses and surface runoff demonstrated a high efficiency in the simulation of hydrological processes. The basin of Orós reservoir presented a high variability of the coefficient of surface runoff, justifying the need for a greater spatiality of this coefficient in heterogeneous environments.

Power Transformer Fault Diagnosis Based on Vibration Correlation Analysis

2014 ◽  
Author(s):  
Kaixing Hong ◽  
Hai Huang
Keyword(s):  
Fault Diagnosis ◽  
Correlation Analysis ◽  
Fundamental Frequency ◽  
Vibration Analysis ◽  
Laboratory Tests ◽  
Power Transformer ◽  
Assessment Model ◽  
Vibration Method ◽  
Proposed Model ◽  
Transformer Fault

In this paper, a condition assessment model using vibration method is presented to diagnose winding structure conditions. The principle of the model is based on the vibration correlation. In the model, the fundamental frequency vibration analysis is used to separate the winding vibration from the tank vibration. Then, a health parameter is proposed through the vibration correlation analysis. During the laboratory tests, the model is validated on a test transformer, and manmade deformations are provoked in a special winding to compare the vibrations under different conditions. The results show that the proposed model has the ability to assess winding conditions.

scholarly journals PROPOSING A NEW METHODOLOGY BASED ON FUZZY LOGIC FOR TUNNELLING RISK ASSESSMENT

2014 ◽  
Vol 20 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Abdolreza Yazdani-Chamzini
Keyword(s):  
Risk Assessment ◽  
Fuzzy Inference ◽  
Assessment Model ◽  
Tunnel Construction ◽  
Construction Operations ◽  
Protective Measures ◽  
Inference System ◽  
Proposed Model ◽  
Mine Development ◽  
Civil Defence

Tunnels are artificial underground spaces that provide a capacity for particular goals such as storage, under-ground transportation, mine development, power and water treatment plants, civil defence. This shows that the tunnel construction is a key activity in developing infrastructure projects. In many situations, tunnelling projects find themselves involved in the situations where unexpected conditions threaten the continuity of the project. Such situations can arise from the prior knowledge limited by the underground unknown conditions. Therefore, a risk analysis that can take into account the uncertainties associated with the underground projects is needed to assess the existing risks and prioritize them for further protective measures and decisions in order to reduce, mitigate and/or even eliminate the risks involved in the project. For this reason, this paper proposes a risk assessment model based on the concepts of fuzzy set theory to evaluate risk events during the tunnel construction operations. To show the effectiveness of the proposed model, the results of the model are compared with those of the conventional risk assessment. The results demonstrate that the fuzzy inference system has a great potential to accurately model such problems.

Learning from failures: Design improvements using a multiple criteria decision-making process

2003 ◽  
Vol 217 (4) ◽  
pp. 207-216 ◽  
Author(s):  
G G Davidson ◽  
A W Labib
Keyword(s):  
Decision Making ◽  
Failure Modes ◽  
Multiple Criteria Decision Making ◽  
Multiple Criteria ◽  
Mathematical Representation ◽  
Analytic Hierarchy ◽  
Proposed Model ◽  
Invaluable Tool ◽  
History Of

This paper proposes a new concept of decision analysis based on a multiple criteria decision making (MCDM) process. This is achieved through the provision of a systematic and generic methodology for the implementation of design improvements based on experience of past failures. This is illustrated in the form of a case study identifying the changes made to Concorde after the 2000 accident. The proposed model uses the analytic hierarchy process (AHP) mathematical model as a backbone and integrates elements of a modified failure modes and effects analysis (FMEA). The AHP has proven to be an invaluable tool for decision support since it allows a fully documented and transparent decision to be made with full accountability. In addition, it facilitates the task of justifying improvement decisions. The paper is divided as follows: the first section presents an outline of the background to the Concorde accident and its history of related (non-catastrophic) malfunctions. The AHP methodology and its mathematical representation are then presented with the integrated FMEA applied to the Concorde accident. The case study arrives at the same conclusion as engineers working on Concorde after the accident: that the aircraft may fly again if the lining of the fuel tanks are modified.

scholarly journals Second-order total generalized variation based model for restoring images with mixed Poisson — Gaussian noise

2021 ◽  
pp. 20-32
Author(s):  
Cong Pham ◽  
Thi Thu Thao Tran ◽  
Thanh Cong Nguyen ◽  
Duc Hoang Vo
Keyword(s):  
Gaussian Noise ◽  
High Efficiency ◽  
Gaussian Model ◽  
Second Order ◽  
Total Generalized Variation ◽  
Proposed Model ◽  
Total Variation Model ◽  
Alternating Minimization Algorithm ◽  
Generalized Variation ◽  
Noise Models

Introduction: A common problem in image restoration is image denoising. Among many noise models, the mixed Poisson-Gaussian model has recently aroused considerable interest. Purpose: Development of a model for denoising images corrupted by mixed Poisson-Gaussian noise, along with an algorithm for solving the resulting minimization problem. Results: We proposed a new total variation model for restoring an image with mixed Poisson-Gaussian noise, based on second-order total generalized variation. In order to solve this problem, an efficient alternating minimization algorithm is used. To illustrate its comparison with related methods, experimental results are presented, demonstrating the high efficiency of the proposed approach. Practical relevance: The proposed model allows you to remove mixed Poisson-Gaussian noise in digital images, preserving the edges. The presented numerical results demonstrate the competitive features of the proposed model.

scholarly journals Quantifying the Environmental and Economic Performance of Remote Communities

2019 ◽  
Vol 8 (4) ◽  
pp. 176 ◽  
Author(s):  
Jamie Filer ◽  
Steven Schuldt
Keyword(s):  
Management Practices ◽  
Sustainability Assessment ◽  
Assessment Model ◽  
Remote Site ◽  
Construction Costs ◽  
Remote Communities ◽  
Renewable Energy Systems ◽  
Proposed Model ◽  
Waste Management Practices ◽  
Post Disaster

Remote communities such as oil production sites, post-disaster housing camps, and military forwardoperating bases (FOB) are often detached from established infrastructure grids, requiring a constantresupply of resources. In one instance, a 600-person FOB required 22 trucks per day to delivernecessary fuel and water and remove generated wastes. This logistical burden produces negativeenvironmental impacts and increases operational costs. To minimize these consequences,construction planners can implement sustainability measures such as renewable energy systems,improved waste management practices, and energy-efficient equipment. However, integration ofsuch upgrades can increase construction costs, presenting the need for a tool that identifies tradeoffsamong conflicting criteria. To assist planners in these efforts, this paper presents the development ofa novel remote site sustainability assessment model capable of quantifying the environmental andeconomic performance of a set of infrastructure alternatives. Through field data and literatureestimates, a hypothetical FOB is designed and evaluated to demonstrate the model’s distinctivecapability to accurately and efficiently assess construction alternatives. The proposed model willenable construction planners to maximize the sustainability of remote communities, creating sitesthat are more self-sufficient with reduced environmental impacts.Keywords: Sustainability, infrastructure, remote communities

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