Approaches to improve the robustness on interdependent networks against cascading failures with load-based model

2015 ◽  
Vol 29 (32) ◽  
pp. 1550210 ◽  
Author(s):  
Zhengcheng Dong ◽  
Yanjun Fang ◽  
Meng Tian ◽  
Rong Zhang
Keyword(s):  
Coupling Strength ◽  
Initial Period ◽  
Network Construction ◽  
Interdependent Networks ◽  
Coupled Networks ◽  
Novel Method ◽  
One To One ◽  
The Cost ◽  
Full Investigation ◽  
Link Pattern

With load-based model, considering the loss of capacity on nodes, we investigate how the coupling strength (many-to-many coupled pattern) and link patterns (one-to-one coupled pattern) can affect the robustness of interdependent networks. In one-to-one coupled pattern, we take into account the properties of degree and betweenness, and adopt four kinds of inter-similarity link patterns and random link pattern. In many-to-many coupled pattern, we propose a novel method to build new networks via adding inter-links (coupled links) on the existing one-to-one coupled networks. For a full investigation on the effects, we conduct two types of attack strategies, i.e. RO-attack (randomly remove only one node) and RF-attack (randomly remove a fraction of nodes). We numerically find that inter-similarity link patterns and bigger coupling strength can effectively improve the robustness under RO-attacks and RF-attacks in some cases. Therefore, the inter-similarity link patterns can be applied during the initial period of network construction. Once the networks are completed, the robustness level can be improved via adding inter-links appropriately without changing the existing inter-links and topologies of networks. We also find that BA–BA topology is a better choice and that it is not useful to infinitely increase the capacity which is defined as the cost of networks.

scholarly journals Cost Analysis of a Novel Method for Ecological Compensation—A Study of the Translocation of Dead Wood

2021 ◽  
Vol 13 (11) ◽  
pp. 6075
Author(s):  
Ola Lindroos ◽  
Malin Söderlind ◽  
Joel Jensen ◽  
Joakim Hjältén
Keyword(s):  
Cost Efficiency ◽  
Dead Wood ◽  
Road Transportation ◽  
Ecological Value ◽  
Ecological Compensation ◽  
Work Time ◽  
Delivery Times ◽  
Novel Method ◽  
Cost Efficient ◽  
The Cost

Translocation of dead wood is a novel method for ecological compensation and restoration that could, potentially, provide a new important tool for biodiversity conservation. With this method, substrates that normally have long delivery times are instantly created in a compensation area, and ideally many of the associated dead wood dwelling organisms are translocated together with the substrates. However, to a large extent, there is a lack of knowledge about the cost efficiency of different methods of ecological compensation. Therefore, the costs for different parts of a translocation process and its dependency on some influencing factors were studied. The observed cost was 465 SEK per translocated log for the actual compensation measure, with an additional 349 SEK/log for work to enable evaluation of the translocation’s ecological results. Based on time studies, models were developed to predict required work time and costs for different transportation distances and load sizes. Those models indicated that short extraction and insertion distances for logs should be prioritized over road transportation distances to minimize costs. They also highlighted a trade-off between costs and time until a given ecological value is reached in the compensation area. The methodology used can contribute to more cost-efficient operations and, by doing so, increase the use of ecological compensation and the benefits from a given input.

scholarly journals Embedding Undersampling Rotation Forest for Imbalanced Problem

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Huaping Guo ◽  
Xiaoyu Diao ◽  
Hongbing Liu
Keyword(s):  
Imbalanced Data ◽  
Feature Space ◽  
Original Data ◽  
Training Set ◽  
Data Set ◽  
Minority Class ◽  
Rotation Forest ◽  
Novel Method ◽  
Individual Classifier ◽  
The Cost

Rotation Forest is an ensemble learning approach achieving better performance comparing to Bagging and Boosting through building accurate and diverse classifiers using rotated feature space. However, like other conventional classifiers, Rotation Forest does not work well on the imbalanced data which are characterized as having much less examples of one class (minority class) than the other (majority class), and the cost of misclassifying minority class examples is often much more expensive than the contrary cases. This paper proposes a novel method called Embedding Undersampling Rotation Forest (EURF) to handle this problem (1) sampling subsets from the majority class and learning a projection matrix from each subset and (2) obtaining training sets by projecting re-undersampling subsets of the original data set to new spaces defined by the matrices and constructing an individual classifier from each training set. For the first method, undersampling is to force the rotation matrix to better capture the features of the minority class without harming the diversity between individual classifiers. With respect to the second method, the undersampling technique aims to improve the performance of individual classifiers on the minority class. The experimental results show that EURF achieves significantly better performance comparing to other state-of-the-art methods.

Design of Fazl-Tash novel method for sustainable resilient comprehensive supplier selection problem

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamed Fazlollahtabar ◽  
Navid Kazemitash
Keyword(s):  
Supplier Selection ◽  
Huge Number ◽  
Simple Method ◽  
Content Type ◽  
Novel Method ◽  
Rank And Select ◽  
The Cost ◽  
Supplier Selection Problem ◽  
Industrial Company

Purpose However, due to the huge number of studies and on the other hand to be new and creative, the represented models and methods – as the two main parts of this field – have been got more complicated, which consequently have been turned into unpractical research studies for the realistic situations. Therefore, the purpose of this study is the representation of a novel and simple method to deal with the aforementioned gap. Design/methodology/approach To this end, Fazl-Tash method have been proposed, in which a thorough and complete model including 114 criteria and a simple technique to rank and select the best supplier have been presented. Sustainability and resiliency are considered in collecting criteria effective on supplier selection. Findings The method was carried out in a case study in an industrial company. The efficiency of the proposed method is evaluated in comparison with other conventional approaches. Originality/value As selecting the supplier plays a crucial role to bring some important advantages for companies, such as coping with the cost and time problems and influencing the majority of contemporary markets’ requirements, in recent years, there have been representing more effective studies in the supplier selection literature.

A hybrid framework to model factors affecting construction labour productivity

2019 ◽  
Vol 24 (3) ◽  
pp. 630-654 ◽  
Author(s):  
Majid Parchami Jalal ◽  
Shahab Shoar
Keyword(s):  
Construction Industry ◽  
Labour Productivity ◽  
Content Type ◽  
Factors Affecting ◽  
Schedule Delay ◽  
Factors Influencing ◽  
Hybrid Framework ◽  
Novel Method ◽  
The Cost ◽  
The Impact

Purpose This paper aims to model different causal relations among factors interacting with labour productivity in order to recognize the most important factors influencing and influenced by it. Design/methodology/approach Top 60 factors affecting labour productivity were determined and grouped into 5 major groups by reviewing previous research and interviewing relevant experts. The interactions of factors were modelled using system dynamics (SD) approach. The resulting causal loop diagrams obtained from SD were then applied for identifying the most crucial factors influencing and influenced by labour productivity through the decision-making trial and evaluation laboratory (DEMATEL) method. The impact of factors on each other was finally determined based on the opinions of 63 experts selected from the Iranian construction industry. Findings The results indicated that factors such as fatigue, lack of labour motivation and lack of skill are the most influencing, and factors such as schedule delay and inflation in the cost of execution are the most influenced by labour productivity. In the end, a set of recommendations to improve construction labour productivity was also presented. Originality/value The main contribution of the study is proposing a novel method which is capable of providing insights into how causes and effects of construction labour productivity are interrelated. Furthermore, the proposed method makes this study distinct from previous research in the light of prioritizing factors and offering recommendations according to the interrelationships among factors.

EPIDEMIC SPREADING ON THREE-LAYER INTERDEPENDENT NETWORKS

2016 ◽  
Vol 24 (04) ◽  
pp. 469-494 ◽  
Author(s):  
LINGNA WANG ◽  
GUANGHU ZHU ◽  
HUIYAN KANG ◽  
XINCHU FU
Keyword(s):  
Infection Rate ◽  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Mean Field ◽  
Network Size ◽  
Infection Rates ◽  
Epidemic Spreading ◽  
Interdependent Networks ◽  
Coupled Networks ◽  
The Basic Reproduction Number

Many epidemic diseases spread among three different populations with different contact patterns and infection rates. In response to such diseases, we propose two new types of three-layer interdependent networks — string-coupled networks and circular-coupled networks. We investigate an epidemic spreading on the two types of interdependent networks, propose two mathematical models through heterogeneous mean field approach and prove global stability of the disease-free and endemic equilibria. Through theoretical and numerical analysis, we find the following: the increase of each infection rate affects effectively only its own subnetwork and neighbors; in a string-coupled network, the middle subnetwork has bigger impact on the basic reproduction number than the end subnetworks with the growth of network size or infection rates; the basic reproduction number on a circular-coupled network is larger than that on a string-coupled network for a fixed network size; but the change of the basic reproduction number (or the average infection densities) is almost the same on both string-coupled and circular-coupled networks with the increasing of certain infection rate.

Classification with Local Clustering in Imbalanced Data Sets

2011 ◽  
Vol 219-220 ◽  
pp. 151-155 ◽  
Author(s):  
Hua Ji ◽  
Hua Xiang Zhang
Keyword(s):  
Data Distribution ◽  
Imbalanced Data ◽  
Support Vector ◽  
Data Sets ◽  
Data Set ◽  
Imbalanced Data Sets ◽  
Local Clustering ◽  
Rare Class ◽  
Novel Method ◽  
The Cost

In many real-world domains, learning from imbalanced data sets is always confronted. Since the skewed class distribution brings the challenge for traditional classifiers because of much lower classification accuracy on rare classes, we propose the novel method on classification with local clustering based on the data distribution of the imbalanced data sets to solve this problem. At first, we divide the whole data set into several data groups based on the data distribution. Then we perform local clustering within each group both on the normal class and the disjointed rare class. For rare class, the subsequent over-sampling is employed according to the different rates. At last, we apply support vector machines (SVMS) for classification, by means of the traditional tactic of the cost matrix to enhance the classification accuracies. The experimental results on several UCI data sets show that this method can produces much higher prediction accuracies on the rare class than state-of-art methods.

scholarly journals Online Reference Trajectory Adaptation: A Personalized Control Strategy for Lower Limb Exoskeletons

2021 ◽  
Author(s):  
Mohammad Shushtari ◽  
Rezvan Nasiri ◽  
Arash Arami
Keyword(s):  
Cost Function ◽  
Lower Limb ◽  
Interaction Force ◽  
Reference Trajectory ◽  
Time Symmetry ◽  
Spatiotemporal Parameters ◽  
Novel Method ◽  
The Cost ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

This paper presents a novel method for reference trajectory adaptation in lower limb rehabilitation exoskeletons during walking. Our adaptation rule is extracted from a cost function that penalizes both interaction force and trajectory modification. By adding trajectory modification term into the cost function, we restrict the boundaries of the reference trajectory adaptation according to the patient's motor capacity. The performance of the proposed adaptation method is studied analytically in terms of convergence and optimality. We also developed a realistic dynamic walking simulator and utilized it in performance analysis of the presented method. The proposed trajectory adaptation technique guarantees convergence to a stable, reliable, and rhythmic reference trajectory with no prior knowledge about the human intended motion. Our simulations demonstrate the convergence of exoskeleton trajectories to those of simulated healthy subjects while the exoskeleton trajectories adapt less to the trajectories of patients with reduced motor capacity (less reliable trajectories). Furthermore, the gait stability and spatiotemporal parameters such as step time symmetry and minimum toe off clearance enhanced by the adaptation in all subjects. The presented mathematical analysis and simulation results show the applicability and effectiveness of the proposed method and its potential to be applied for trajectory adaptation in lower limb rehabilitation exoskeletons.

Pressure-Retarded Osmosis Thermosyphon

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Francisco J. Arias ◽  
Salvador de las Heras
Keyword(s):  
Natural Convection ◽  
Salinity Gradient ◽  
Fluid Motion ◽  
High Concentration ◽  
Thermal Dependence ◽  
Heat And Mass Transport ◽  
Pressure Retarded Osmosis ◽  
Dense Fluid ◽  
Novel Method ◽  
The Cost

The basis of a novel method for passive solar water heating homologous to the traditional thermosyphon but driven by salinity gradient induced by changes of salinity gradient induced by evaporation at the collector is outlined. Its purpose, likewise than a thermosyphon, is to simplify the transfer of liquid while avoiding the cost and complexity of a conventional pump. However, in this concept, the fluid motion is not obtained from the tendency of a less dense fluid to rise above a denser fluid (natural convection) but rather by taking advantage of the energy released during the spontaneous mixing of the low-concentration (evaporated fraction) solution and the high-concentration (no-evaporated fraction) solution, which have been previously separated into two streams in the evaporator module. Finally, the possibility of driving the thermal osmosis by the strong thermal dependence of the solubility featured by many solutions rather than evaporation is envisaged. One important point in favor of the proposed thermosyphon driven by thermo-osmosis is that makes possible downward heat and mass transfer, i.e., heat and mass transport from the top roofs (where solar collectors are generally placed) to the bottom (inside the homes), and then the use of expensive and voluminous tanks so characteristic of current thermosyphons driven by natural convection is no longer needed.

Estimating raindrop size distributions and vertical air motions with spectral difference using vertically pointing radar

2021 ◽  
Author(s):  
Suzhou Pang ◽  
Zheng Ruan ◽  
Ling Yang ◽  
Xiantong Liu ◽  
Zhaoyang Huo ◽  
...  
Keyword(s):  
Shape Function ◽  
Retrieval Algorithm ◽  
Accurate Estimation ◽  
Size Distributions ◽  
Spectral Difference ◽  
Microphysical Process ◽  
Novel Method ◽  
Raindrop Size ◽  
The Cost ◽  
Function Difference

AbstractDoppler spectra measured by vertically pointing radars are inherently linked to raindrop size distributions (DSDs). But, accurate estimation of DSDs remains challenging because raindrop spectra are broadened by atmospheric turbulence and shifted by vertical air motions. This paper presents a novel method to estimate vertical air motions that there is no need to assume a model for DSD at each range gate. The theory of the new method is that the spectral difference between the adjacent range gates is contributed by vertical air motions and the variability of DSDs. The contribution of the change of DSDs is estimated by looking up the prepared tables (LUTs) of raindrop velocity difference and shape function difference. Then, the vertical air motions can be estimated by minimizing the cost function of the two spectra between the adjacent range gates. The retrieval algorithm is applied to three cases including a stratiform and two convective observed by a C band vertically pointing radar in Longmen, Guangdong province of China in June 2016. Before that, the spectrum broadening effect is removed by the traditional deconvolution method with a wind profiler. The vertical profiles of precipitation parameters are also retrieved to investigate the microphysical process. The precipitation parameters retrieved near the surface are compared with the ground data collected by a two-dimensional video disdrometer(2DVD) and the results show good agreements.

Economic study of maintenances and outage resolution in an electricity distribution network using the continuous-time Markov chain

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Navid Nazhand ◽  
Reza Dashti ◽  
Abolfazl Ahmadi
Keyword(s):  
Human Resources ◽  
Continuous Time ◽  
Design Methodology ◽  
Electricity Distribution ◽  
Continuous Time Markov Chain ◽  
Economic Study ◽  
Content Type ◽  
Novel Method ◽  
The Cost

PurposeThe purpose of this paper is to describe a novel method to compromise between planned (regulated) maintenance and outage initiation and unplanned (unregulated) maintenance and to find an economic model using which one can perform maintenance adequately and in the most optimal state.Design/methodology/approachIn this paper, a system consisting of similar components is considered, and the role of each component in the system is explained. Then, the cost pertaining to failure in each asset is determined. Costs such as energy not supplied, penalties, human resources to resolve the defect and replacing assets are taken into account. Finally, a new comprehensive objective is proposed, and optimization is performed for a sample system.FindingsIn this paper, some graphs have been plotted from which plenty of information may be extracted. This is mentioned in the Conclusion.Originality/valueIn this paper, some graphs have been plotted from which plenty of information may be extracted. This is mentioned in the Conclusion.

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