scholarly journals Mathematical Foundations for Efficient Structural Controllability and Observability Analysis of Complex Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Pedro J. Zufiria ◽  
Luis Úbeda-Medina ◽  
Carlos Herrera-Yagüe ◽  
Iker Barriales-Valbuena
Keyword(s):  
Complex Systems ◽  
Large Scale ◽  
Design Problems ◽  
Graph Theoretic ◽  
Structural Controllability ◽  
Controllability And Observability ◽  
Mathematical Foundations ◽  
The Relationship ◽  
Theoretical Results ◽  
New Algorithms

The relationship between structural controllability and observability of complex systems is studied. Algebraic and graph theoretic tools are combined to prove the extent of some controller/observer duality results. Two types of control design problems are addressed and some fundamental theoretical results are provided. In addition new algorithms are presented to compute optimal solutions for monitoring large scale real networks.

scholarly journals Algorithm for Identifying Minimum Driver Nodes Based on Structural Controllability

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Reza Haghighi ◽  
HamidReza Namazi
Keyword(s):  
Large Scale ◽  
Simple Graph ◽  
Networked Systems ◽  
Infinite Time ◽  
Input Signals ◽  
Graph Reachability ◽  
Structural Controllability ◽  
Practical Model ◽  
Simulation Results ◽  
The Relationship

Existing methods on structural controllability of networked systems are based on critical assumptions such as nodal dynamics with infinite time constants and availability of input signals to all nodes. In this paper, we relax these assumptions and examine the structural controllability for practical model of networked systems. We explore the relationship between structural controllability and graph reachability. Consequently, a simple graph-based algorithm is presented to obtain the minimum driver nodes. Finally, simulation results are presented to illustrate the performance of the proposed algorithm in dealing with large-scale networked systems.

scholarly journals A Belief Rule-Based Safety Evaluation Approach for Complex Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jun Zhang ◽  
Jiang Jiang ◽  
Yingwu Chen ◽  
Kewei Yang
Keyword(s):  
Complex Systems ◽  
Large Scale ◽  
Safety Evaluation ◽  
Rule Base ◽  
Negative Effects ◽  
Rule Based ◽  
Evaluation Approach ◽  
Reasoning Algorithm ◽  
The Relationship ◽  
Estimation Of Uncertainty

Plenty of hazards underlie complex systems, which have negative effects on the normal functionality of engineering events. To minimize the uncertainty, a comprehensive preevent checkout is necessarily required to judge if the engineering events will be carried out successfully under current circumstance, through which further improvements can be made. A generic belief rule-based safety evaluation approach for large-scale complex systems is proposed. The overall system is firstly decomposed and filtered into the measurable attributes that may potentially contribute to uncertainty. Belief structure is then applied to measure the uncertainty of vagueness and incompleteness and represent heterologous information in a unified scheme. With this scheme, a rule base is established with all antecedents, consequents, and attributes presented in belief degrees, which is used to determine the relationship between attributes, aggregate the influences, and generate the final inference with evidential reasoning algorithm. In the end, an estimation of uncertainty is achieved in the representation of distribution. It describes how the systems perform with given conditions and sources. A numeric case in aerospace program is provided for feasibility illustration.

scholarly journals The technology of using fuzzy cognitive maps from a mathematical point of view

2021 ◽  
pp. 1-22
Author(s):  
Yuri Germanovich Rykov
Keyword(s):  
Complex Systems ◽  
System Dynamics ◽  
Cognitive Maps ◽  
Cognitive Map ◽  
Point Of View ◽  
Fuzzy Cognitive Maps ◽  
Generalized System ◽  
Computational Procedures ◽  
The Relationship ◽  
Theoretical Results

A broader view of the technology of fuzzy cognitive maps is described, in which the cognitive map is considered as a carrier of computational procedures. This approach can be described as a generalized system dynamics. This interpretation makes it easier to obtain theoretical results that can characterize the behavior of complex systems. In particular, in the case of simple computational procedures, the relationship between the degree of influence of factors and the structure of the system, namely, the presence of connecting paths and cycles in the corresponding digraph, is clarified.

Application of System Engineering to Project Management

2018 ◽  
Vol 7 (4) ◽  
pp. 76-97 ◽  
Author(s):  
Brian J. Galli
Keyword(s):  
Decision Making ◽  
Project Management ◽  
Complex Systems ◽  
Research And Development ◽  
Success Rate ◽  
Large Scale ◽  
System Engineering ◽  
Development Organizations ◽  
The Relationship ◽  
Engineering Projects

System engineering in complex systems has transitioned into a well detailed, universally accepted, client-oriented methodology. Unfortunately, this approach hasn't been adopted in most commercially mandated research and development organizations. This article acknowledges that to improve the success of projects, it is essential to understand the benefits of managing product requirement with system engineering. In discussion is the application of system engineering in improving the success rate through better requirement handling. It presents the elements of the relationship between system engineering and project management. The findings suggest that the full importance of applying system engineering can only be enjoyed if other pre-requisites on prudent decision-making are applied. Furthermore, the findings suggest guidance on ways of adopting system-engineering (SE) practices when implementing in large-scale engineering projects.

scholarly journals Intuitionistic Layered Graph Logic

2017 ◽  
Author(s):  
Simon Docherty ◽  
David Pym
Keyword(s):  
Social Sciences ◽  
Complex Systems ◽  
Completeness Theorem ◽  
Kripke Semantics ◽  
Substructural Logic ◽  
Graph Theoretic ◽  
Soundness And Completeness ◽  
The Relationship ◽  
Layered Graph

Models of complex systems are widely used in the physical and social sciences, and the concept of layering, typically building upon graph-theoretic structure, is a common feature. We describe an intuitionistic substructural logic that gives an account of layering. As in other bunched systems, the logic includes the usual intuitionistic connectives, together with a non-commutative, non-associative conjunction (used to capture layering) and its associated implications. We give a soundness and completeness theorem for a labelled tableaux system with respect to a Kripke semantics on graphs. To demonstrate the utility of the logic, we show how to represent systems and security examples, illuminating the relationship between services/policies and the infrastructures/architectures to which they are applied.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

New ''Cold War''

2020 ◽  
pp. 27-34
Author(s):  
Vladimir Batiuk
Keyword(s):  
Cold War ◽  
Nuclear Weapons ◽  
Armed Conflict ◽  
Large Scale ◽  
Arms Race ◽  
Ideological Struggle ◽  
Nuclear Arms Race ◽  
The Cold War ◽  
The Relationship ◽  
Nuclear Arms

In this article, the ''Cold War'' is understood as a situation where the relationship between the leading States is determined by ideological confrontation and, at the same time, the presence of nuclear weapons precludes the development of this confrontation into a large-scale armed conflict. Such a situation has developed in the years 1945–1989, during the first Cold War. We see that something similar is repeated in our time-with all the new nuances in the ideological struggle and in the nuclear arms race.

Investigating Diseases and Chemicals in COVID-19 Literature with Text Mining (Preprint)

2020 ◽  
Author(s):  
Amir Karami ◽  
Brandon Bookstaver ◽  
Melissa Nolan
Keyword(s):  
Text Mining ◽  
Literature Review ◽  
Topic Modeling ◽  
Large Scale ◽  
Clinical Manifestations ◽  
International Health ◽  
Research Papers ◽  
Strategic Plans ◽  
Funding Agencies ◽  
The Relationship

BACKGROUND The COVID-19 pandemic has impacted nearly all aspects of life and has posed significant threats to international health and the economy. Given the rapidly unfolding nature of the current pandemic, there is an urgent need to streamline literature synthesis of the growing scientific research to elucidate targeted solutions. While traditional systematic literature review studies provide valuable insights, these studies have restrictions, including analyzing a limited number of papers, having various biases, being time-consuming and labor-intensive, focusing on a few topics, incapable of trend analysis, and lack of data-driven tools. OBJECTIVE This study fills the mentioned restrictions in the literature and practice by analyzing two biomedical concepts, clinical manifestations of disease and therapeutic chemical compounds, with text mining methods in a corpus containing COVID-19 research papers and find associations between the two biomedical concepts. METHODS This research has collected papers representing COVID-19 pre-prints and peer-reviewed research published in 2020. We used frequency analysis to find highly frequent manifestations and therapeutic chemicals, representing the importance of the two biomedical concepts. This study also applied topic modeling to find the relationship between the two biomedical concepts. RESULTS We analyzed 9,298 research papers published through May 5, 2020 and found 3,645 disease-related and 2,434 chemical-related articles. The most frequent clinical manifestations of disease terminology included COVID-19, SARS, cancer, pneumonia, fever, and cough. The most frequent chemical-related terminology included Lopinavir, Ritonavir, Oxygen, Chloroquine, Remdesivir, and water. Topic modeling provided 25 categories showing relationships between our two overarching categories. These categories represent statistically significant associations between multiple aspects of each category, some connections of which were novel and not previously identified by the scientific community. CONCLUSIONS Appreciation of this context is vital due to the lack of a systematic large-scale literature review survey and the importance of fast literature review during the current COVID-19 pandemic for developing treatments. This study is beneficial to researchers for obtaining a macro-level picture of literature, to educators for knowing the scope of literature, to journals for exploring most discussed disease symptoms and pharmaceutical targets, and to policymakers and funding agencies for creating scientific strategic plans regarding COVID-19.

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