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排序方式: 共有271条查询结果,搜索用时 15 毫秒
81.
On-line fault detection in discrete event systems by Petri nets and integer linear programming 总被引:1,自引:0,他引:1
The paper addresses the fault detection problem for discrete event systems in a Petri Net (PN) framework. Assuming that the structure of the PN model and the initial marking are known, faults are modelled by unobservable transitions. Moreover, we assume that there may be additional unobservable transitions associated with the system legal behaviour and that the marking reached after the firing of any transition is unknown. The proposed diagnoser works on-line: it waits for the firing of an observable transition and employs an algorithm based on the definition and solution of some integer linear programming problems to decide whether the system behaviour is normal or exhibits some possible faults. The results characterize the properties that the PN modelling the system fault behaviour has to fulfill in order to reduce the on-line computational effort. 相似文献
82.
Recent research on compact genetic algorithms (cGAs) has proposed a number of evolutionary search methods with reduced memory requirements. In cGAs, the evolution of populations is emulated by processing a probability vector with specific update rules. This paper considers the implementation of cGAs in microcontroller-based control platforms. In particular, to overcome some problems related to the binary encoding schemes adopted in most cGAs, this paper also proposes a new variant based on a real-valued solution coding. The presented variant achieves final solutions of the same quality as those found by binary cGAs, with a significantly reduced computational cost. The potential of the proposed approach is assessed by means of an extensive comparative study, which includes numerical results on benchmark functions, simulated and experimental microcontroller design problems. 相似文献
83.
Agostino Villa Author Vitae 《Annual Reviews in Control》2007,31(1):107-118
The goals of an organization of data and information collected from the European industrial systems and concerning networks of enterprises, mainly small-mid enterprises (SMEs), are many:
- (a)
- to offer an intelligent support system (ISS) to industrial analysers when they try to understand if a SME network, either cluster or industrial district, could be enforced by proper financing, or it cannot give sufficient assurance for a new development;
- (b)
- to offer to political people a support in understanding the dynamics of these SME networks, in order to be able to take decisions about public politics;
- (c)
- to give tools for analysing the performance of these industrial bodies to industrial people, mainly technicians and managers, such to be able to apply new strategies for their improvement;
- (d)
- to give information and data to researchers operating in university and RTD centers, such to be able to improve their knowledge about these so important industrial bodies.
84.
This work introduces a formal analysis of the non-repudiation property for security protocols. Protocols are modelled in the process calculus LySa, using an extended syntax with annotations. Non-repudiation is verified using a Control Flow Analysis, following the same approach of Buchholtz and Gao for authentication and freshness analyses.The result is an analysis that can statically check the protocols to predict if they are secure during their execution and which can be fully automated. 相似文献
85.
In this paper, we present a refinement of a Control Flow Analysis aimed at studying information flow security in the the calculus of Mobile Ambients. The improvements are achieved by making the analysis be flow-sensitive: the analysis is able to keep track of temporal dependencies of capabilities application when computing a safe approximation of the run-time topology of Mobile Ambient processes. 相似文献
86.
An optimal design of Photonic Band-Gap (PBG) based resonance cavities has been carried out and optimal design rules have been drawn by a very fast and accurate computer code, developed by the authors, implementing a new model of one-dimensional finite-size PBG materials. The model also takes into account the presence of defects; it allows to accurately determine the mode propagation constants, electromagnetic harmonics and total field distribution, transmission and reflection coefficients, forward and backward power flow, guided and radiated power and total losses due to radiation, Bragg scattering and out of plane scattering. The design of resonance cavities advancing the state of the art of commercial Dense Wavelength Division Multiplexing (DWDM) filters is performed. A great number of optical cavities have been designed and quickly simulated thanks to the fastness of the code, allowing optimal design rules to be drawn. 相似文献
87.
Rebecca Kokkinofta Naso Economidou Eleni Tzioni Katerina Damianou Konstantina Poulli Chara Savvidou Charalambos Louka Popi Kanari 《化学与化工:英文版》2014,(2):101-107
The authenticity of 91 wines produced in Cyprus from both indigenous and other vine varieties were investigated by a holistic approach, using, advanced technology such as SNIF-NMR (site-specific natural isotopic fractionation-nuclear magnetic resonance) and 1R-MS (isotope ratio-mass spectrometry) for the determination of the stable isotopes and ICP (inductively coupled plasma spectroscopy) for some heavy metals. The spectroscopic characteristics were evaluated statistically using different chemometric methods. The dependency of the D/H (deuterium/hydrogen) ratio of the methylene site in the ethanol molecule (D/H)ll and also theδ ^18O values of the wine water, were the most useful discriminators. Isotopic results allow us to have a complete idea about the regional variability of the isotopes. Among the metals, Ni followed by Pb was the ones with the highest discrimination value. The determined concentrations of Pb, Ni, Cr and Cd that are related to the safety of wines were within the acceptable limits that have been established by the OIV (international organization of vine and wine) or comparable with the results of the wines of other European countries. The study of the correlation between the load of heavy metals and isotopes in wines showed a dependence on the grape variety but not the geographical location of the vineyard. This is probably due to the close proximity of wine regions in Cyprus. 相似文献
88.
Dr. Luigi Margarucci Dr. Maria Chiara Monti Dr. Maria Giovanna Chini Dr. Alessandra Tosco Prof. Raffaele Riccio Prof. Giuseppe Bifulco Prof. Agostino Casapullo 《Chembiochem : a European journal of chemical biology》2012,13(15):2259-2264
Secretory phospholipases A2 (sPLA2s) are implicated in the pathogenesis of several inflammation diseases, such as rheumatoid arthritis, septic shock, psoriasis, and asthma. Thus, an understanding of their inactivation mechanisms could be useful for the development of new classes of chemical selective inhibitors. In the marine environment, several bioactive terpenoids possess interesting anti‐inflammatory activity, often through covalent and/or noncovalent inactivation of sPLA2. Herein, we report the molecular mechanism of human group IIA phospholipase A2 (sPLA2‐IIA) inactivation by Scalaradial (SLD), a marine 1,4‐dialdehyde terpenoid isolated from the sponge Cacospongia mollior and endowed with a significant anti‐inflammatory profile. Our results have been collected by a combination of biochemical approaches, advanced mass spectrometry, surface plasmon resonance, and molecular modeling. These suggest that SLD acts as a competitive inhibitor. Indeed, the sPLA2‐IIA inactivation process seems to be driven by the noncovalent recognition process of SLD in the enzyme active site and by chelation of the catalytic calcium ion. In contrast, covalent modification of the enzyme by the SLD dialdehyde moiety emerges as only a minor side event in the ligand–enzyme interaction. These results could be helpful for the rational design of new PLA2 inhibitors that would be able to selectively target the enzyme active site. 相似文献
89.
Luca Chittaro Elio Carchietti Luca De Marco Agostino Zampa 《User Modeling and User-Adapted Interaction》2011,21(4-5):407-440
Being able to promptly and accurately choose a proper course of action in the field is a crucial aspect of emergency response. For this reason, emergency medical services (EMS) rely on well established procedures that apply to the most frequent cases first responders encounter in their practice, but do not include special cases concerning (sensory, motor or cognitive) disabled persons. In these cases, first responders may end up applying suboptimal or possibly wrong procedures or lose precious time trying to adapt on-the-fly to the special case. This paper proposes both (i) a detailed patient model for EMS that can account for peculiar aspects of the many existing disabilities and (ii) an adaptive information system called PRESYDIUM (Personalized Emergency System for Disabled Humans) that provides tailored instructions in the field for helping medical first responders in dealing with disabled persons. More precisely, we will illustrate and discuss: (i) the design and development process of PRESYDIUM, (ii) the patient model, which is partly based on the ICF (International Classification of Functioning, Disability and Health) standard proposed by the World Health Organization, (iii) the knowledge base used by the system to provide tailored instructions to medical first responders, (iv) the Web-based architecture of the system, (v) the different interfaces??including one for mobile devices??the system provides to enable all the identified stakeholders (disabled persons, their families, clinicians, EMS call center operators, medical first responders) to easily access and possibly provide data to the system, (vi) the evaluation of the validity of the patient model and of the system usability which has been conducted with end users. 相似文献
90.
Naso D. Surico M. Turchiano B. 《Automation Science and Engineering, IEEE Transactions on》2007,4(3):407-423
This paper considers the problem of coordinating the production and distribution activities of a network of independent supply centers. In particular, we focus on the supply of rapidly perishable goods (ready-mixed concrete) that must be delivered to customers in strict time windows. The problem presents three main challenges. First, it includes several interrelated scheduling and routing problems, each affected by nearly prohibitive combinatorial complexity. Second, due to the perishable nature of the supplied products, effective solutions must not only optimize the objective function related to resource utilization and cost minimization, but also tolerate the small and frequent stochastic perturbations (transport delays) of the operating environment. Third, if major perturbations occur, the decision strategy must be able to respond in real time with effective rescheduling interventions restoring the indispensable synchronization of activities in progress, and avoiding extremely undesirable circumstances related to product decay. After providing a detailed mathematical model of the considered problem, this paper proposes a hybrid metaheuristic approach integrating a genetic algorithm with a number of problem-specific constructive heuristics. The effectiveness of the approach is evaluated against other scheduling heuristics on an industrial case study. 相似文献