Hypothesis Testing and System Identification Methods in Large-scale systems with Hierarchical Structures Applied for On-line Vibration Monitoring of Nuclear Power Reactors

1979 ◽  
Vol 12 (8) ◽  
pp. 1293-1299 ◽  
Author(s):  
E. Saedtler
Keyword(s):  
System Identification ◽  
Hypothesis Testing ◽  
Nuclear Power ◽  
Large Scale ◽  
Hierarchical Structures ◽  
Vibration Monitoring ◽  
Large Scale Systems ◽  
Identification Methods ◽  
On Line

scholarly journals On the Root Causes of the Fukushima Daiichi Disaster from the Perspective of High Complexity and Tight Coupling in Large-Scale Systems

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 414
Author(s):  
Atsuo Murata ◽  
Waldemar Karwowski
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
High Complexity ◽  
Tight Coupling ◽  
Large Scale Systems ◽  
Safety Issues ◽  
Loss Of Coolant ◽  
Station Blackout ◽  
Fukushima Daiichi

This study explores the root causes of the Fukushima Daiichi disaster and discusses how the complexity and tight coupling in large-scale systems should be reduced under emergencies such as station blackout (SBO) to prevent future disasters. First, on the basis of a summary of the published literature on the Fukushima Daiichi disaster, we found that the direct causes (i.e., malfunctions and problems) included overlooking the loss of coolant and the nuclear reactor’s failure to cool down. Second, we verified that two characteristics proposed in “normal accident” theory—high complexity and tight coupling—underlay each of the direct causes. These two characteristics were found to have made emergency management more challenging. We discuss how such disasters in large-scale systems with high complexity and tight coupling could be prevented through an organizational and managerial approach that can remove asymmetry of authority and information and foster a climate of openly discussing critical safety issues in nuclear power plants.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

Hierarchical Parallel Processes of Genetic Algorithms for Design Optimization of Large-Scale Products

2000 ◽  
Author(s):  
Masataka Yoshimura ◽  
Kazuhiro Izui
Keyword(s):  
Genetic Algorithms ◽  
Hierarchical Structure ◽  
Large Scale ◽  
Hierarchical Structures ◽  
Pareto Optimum ◽  
Local Optima ◽  
Large Scale Systems ◽  
Parallel Processes ◽  
The Hierarchical Structure ◽  
Optimization Search

Abstract A large-scale machine system often has a general hierarchical structure. For hierarchical structures, optimization is difficult because many local optima almost always arise, however genetic algorithms that have a hierarchical genotype can be applied to treat such problems directly. Relations between the structural components are analyzed and this information is used to partition the hierarchical structure. Partitioning large-scale problems into sub-problems that can be solved using parallel processed GAs increases the efficiency of the optimization search. The optimization of large-scale systems then becomes possible due to information sharing of Pareto optimum solutions for the sub-problems.

Hierarchical Parallel Processes of Genetic Algorithms for Design Optimization of Large-Scale Products

2004 ◽  
Vol 126 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Masataka Yoshimura ◽  
Kazuhiro Izui
Keyword(s):  
Genetic Algorithms ◽  
Hierarchical Structure ◽  
Large Scale ◽  
Hierarchical Structures ◽  
Pareto Optimum ◽  
Local Optima ◽  
Large Scale Systems ◽  
Parallel Processes ◽  
The Hierarchical Structure ◽  
Optimization Search

A large-scale machine system often has a general hierarchical structure. For hierarchical structures, optimization is difficult because many local optima almost always arise, however genetic algorithms that have a hierarchical genotype can be applied to treat such problems directly. Relations between the structural components are analyzed and this information is used to partition the hierarchical structure. Partitioning large-scale problems into sub-problems that can be solved using parallel processed GAs increases the efficiency of the optimization search. The optimization of large-scale systems then becomes possible due to information sharing of Pareto optimum solutions for the sub-problems.

Role of Cloud Computing in On-Line Social Networking and In-Depth Analysis of Cloud-Sim Simulator

2019 ◽  
pp. 34-46 ◽  
Author(s):  
Suresh Annamalai ◽  
Udendhran R.
Keyword(s):  
Social Networks ◽  
Cloud Computing ◽  
Social Networking ◽  
Large Scale ◽  
System Capacity ◽  
Large Scale Systems ◽  
Depth Analysis ◽  
On Line ◽  
Effective Cost

In this chapter, the authors introduced cloudsim simulator and cloud computing role in online social networking. The communication incurred by other activities such as management jobs is negligible. Social relationships can be established for numerous reasons. For example, family members, colleagues, or classmates often have strong social interactions resulting in large communication load. Cloud computing as well as social network-based applications will become dominant in many aspects of life in the next few decades. The performance of such large-scale systems is characterized by system capacity in terms of number of users/clients, flexibility, scalability, and effective cost of operation, etc. Popular social networks have hundreds of millions of users and continue to grow.

Human-Automation Interaction

2005 ◽  
Vol 1 (1) ◽  
pp. 89-129 ◽  
Author(s):  
Thomas B. Sheridan ◽  
Raja Parasuraman
Keyword(s):  
Computer Technology ◽  
Traffic Control ◽  
Nuclear Power ◽  
Large Scale ◽  
Ethical Issues ◽  
Manufacturing Plants ◽  
Large Scale Systems ◽  
Adaptive Automation ◽  
Qualitative Models ◽  
Military Systems

Automation does not mean humans are replaced; quite the opposite. Increasingly, humans are asked to interact with automation in complex and typically large-scale systems, including aircraft and air traffic control, nuclear power, manufacturing plants, military systems, homes, and hospitals. This is not an easy or error-free task for either the system designer or the human operator/automation supervisor, especially as computer technology becomes ever more sophisticated. This review outlines recent research and challenges in the area, including taxonomies and qualitative models of human-automation interaction; descriptions of automation-related accidents and studies of adaptive automation; and social, political, and ethical issues.

scholarly journals Hierarchical identification of large-scale system models

1997 ◽  
Author(s):  
◽  
Boris R. Jankovic
Keyword(s):  
System Identification ◽  
Large Scale ◽  
Complex Problem ◽  
Hierarchical Identification ◽  
Large Scale Systems ◽  
Large Scale System ◽  
System Models ◽  
The One

In this study we propose a new concept and methodology of hierarchical identification. The need for such a methodology comes from the fact that identification of large-scale systems (LSSs) by one-shot approach may be numerically very complex. The analysis of LSSs is, in general, not approached by the one-shot methodologies normally associated with non-LSSs. The proposed method of hierarchical identification can be therefore viewed as an extension of LSS methodologies to system identification. LSS methodology aims at breaking up the initial, complex problem into a set of smaller size subproblems.

scholarly journals Fault Detection for Large Scale Systems Using Dynamic Principal Components Analysis with Adaptation

2007 ◽  
Vol 2 (2) ◽  
pp. 185 ◽  
Author(s):  
Jesús Mina ◽  
Cristina Verde
Keyword(s):  
Fault Detection ◽  
Large Scale ◽  
Principal Component ◽  
False Alarms ◽  
Large Scale Systems ◽  
Linear Dynamic Systems ◽  
Dynamic Principal Component Analysis ◽  
On Line ◽  
Components Analysis ◽  
Monitoring Phase

The Dynamic Principal Component Analysis is an adequate tool for the monitoring of large scale systems based on the model of multivariate historical data under the assumption of stationarity, however, false alarms occur for non-stationary new observations during the monitoring phase. In order to reduce the false alarms rate, this paper extends the DPCA based monitoring for non-stationary data of linear dynamic systems, including an on-line means estimator to standardize new observations according to the estimated means. The effectiveness of the proposed methodology is evaluated for fault detection in a interconnected tanks system.

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