Search results for "Complex system"
showing 10 items of 226 documents
Low-cost scalable discretization, prediction and feature selection for complex systems
2019
The introduced data-driven tool allows simultaneous feature selection, model inference, and marked cost and quality gains.
The Software Crisis of Synthetic Biology
2016
In fifteen years, Synthetic Biology (SB) has moved from proof-of-concept designs to several flagship achievements. Standardisation efforts are still under way, basic engineering concepts such as modularity and orthogonality are still controversial in biology, and making predictions from computer models is still unreliable. A deep characterization in the pattern of re-use of biological blocks in SB has not been attempted to date. We have compared the topological organisation of two different technological networks, one associated to a standard, large-scale software repository and the second provided by the Registry of Standard Biological Parts (RSBP). Our results strongly suggest that softwa…
2020
Hierarchy and centrality are two popular notions used to characterize the importance of entities in complex systems. Indeed, many complex systems exhibit a natural hierarchical structure, and centrality is a fundamental characteristic allowing to identify key constituents. Several measures based on various aspects of network topology have been proposed in order to quantify these concepts. While numerous studies have investigated whether centrality measures convey redundant information, how centrality and hierarchy measures are related is still an open issue. In this paper, we investigate the association between centrality and hierarchy using several correlation and similarity evaluation mea…
Los programas de cumplimiento penal : Aspectos generales
2021
In Spain, as in many other countries, corporate criminal liability has been a reality for years, as well as criminal compliance programs that allow them to be mitigated or exonerated from liability. In this article we will present some of the main keys to consider for the implementation of these mechanisms. This is a series of general considerations that can serve as a guide to understand the complex system of crime prevention provided by the organization and management models in the corporate environment.
The linear absorbances method adapted to systems with two interfering compounds
1993
The paper exposes the theoretical and experimental study performed with the purpose to extend the application of the Linear Absorbances Method to more complex systems, which present two spectral interferences. The curves of collinearity are developed and a theoretical study of them is carried out. The theoretical equations developed are experimentally tested and the influence of the variables involved in the Linear Absorbance Method is studied, too. It is concluded that the use of couples of collinear wavelengths of the interferents allows to obtain the concentration of a compound in the presence of two interfering substances.
Knowledge Discovery from Network Logs
2015
Modern communications networks are complex systems, which facilitates malicious behavior. Dynamic web services are vulnerable to unknown intrusions, but traditional cyber security measures are based on fingerprinting. Anomaly detection differs from fingerprinting in that it finds events that differ from the baseline traffic. The anomaly detection methodology can be modelled with the knowledge discovery process. Knowledge discovery is a high-level term for the whole process of deriving actionable knowledge from databases. This article presents the theory behind this approach, and showcases research that has produced network log analysis tools and methods. peerReviewed
Instantaneous Transfer Entropy for the Study of Cardiovascular and Cardio-Respiratory Nonstationary Dynamics
2017
Objective: Measures of transfer entropy (TE) quantify the direction and strength of coupling between two complex systems. Standard approaches assume stationarity of the observations, and therefore are unable to track time-varying changes in nonlinear information transfer with high temporal resolution. In this study, we aim to define and validate novel instantaneous measures of TE to provide an improved assessment of complex nonstationary cardiorespiratory interactions. Methods: We here propose a novel instantaneous point-process TE (ipTE) and validate its assessment as applied to cardiovascular and cardiorespiratory dynamics. In particular, heartbeat and respiratory dynamics are characteriz…
ELSA air traffic simulator: An empirically grounded agent based model for the SESAR scenario
2015
This paper describes the Air Traffic Simulator produced by the ELSA project. It is partially based on interacting agents taking actions during strategic and tactical phases: air companies, network manager, pilots, and controllers. The simulator is highly modular and each part can be used independently of the others. The code is open source, ready to use and available for the research community. Some results concerning the future organization of the European Airspace (free-routing) are presented, using the full capabilities of the model. We found that the implementation of free-routing could have a positive impact on the safety event occurrences that will be reduced in number although spread…
Coupling and Complexity of Interaction of STCA Networks
2009
This paper provides an overview on the results of an ENAV feasibility study, where we exploited an automatic safety data gathering tool to analyze the ATM system performances. In particular, it addresses the use of the EUROCONTROL tool, ASMT (Automatic Safety Monitoring Tool), as a support to monitor STCA performance. The contribution of this study is to explore how analysis methods derived from complex systems theory (i.e. network analysis) can assist in the understanding, monitoring and management of the performance of ATM systems. Our data show that a large number of STCAs do not occur in isolation, but rather that in roughly half of the cases the aircraft involved in an STCA are subsequ…
Kontsevich formality and cohomologies for graphs
2004
A formality on a manifold M is a quasi isomorphism between the space of polyvector fields (Tpoly(M)) and the space of multidifferential operators (Dpoly(M)). In the case M=R d , such a mapping was explicitly built by Kontsevich, using graphs drawn in configuration spaces. Looking for such a construction step by step, we have to consider several cohomologies (Hochschild, Chevalley, and Harrison and Chevalley) for mappings defined on Tpoly. Restricting ourselves to the case of mappings defined with graphs, we determine the corresponding coboundary operators directly on the spaces of graphs. The last cohomology vanishes.