PALS-Based Analysis of an Airplane Multirate Control System in Real-Time Maude

Distributed cyber-physical systems (DCPS) are pervasive in areas such as aeronautics and ground transportation systems, including the case of distributed hybrid systems. DCPS design and verification is quite challenging because of asynchronous communication, network delays, and clock skews. Furthermore, their model checking verification typically becomes unfeasible due to the huge state space explosion caused by the system's concurrency. The PALS ("physically asynchronous, logically synchronous") methodology has been proposed to reduce the design and verification of a DCPS to the much simpler task of designing and verifying its underlying synchronous version. The original PALS methodology assumes a single logical period, but Multirate PALS extends it to deal with multirate DCPS in which components may operate with different logical periods. This paper shows how Multirate PALS can be applied to formally verify a nontrivial multirate DCPS. We use Real-Time Maude to formally specify a multirate distributed hybrid system consisting of an airplane maneuvered by a pilot who turns the airplane according to a specified angle through a distributed control system. Our formal analysis revealed that the original design was ineffective in achieving a smooth turning maneuver, and led to a redesign of the system that satisfies the desired correctness properties. This shows that the Multirate PALS methodology is not only effective for formal DCPS verification, but can also be used effectively in the DCPS design process, even before properties are verified.Comment: In Proceedings FTSCS 2012, arXiv:1212.657

Resource Sharing in the U.S. Academic Libraries: Trends and Future

Il servizio di prestito interbibliotecario nelle biblioteche universitarie americane è uno dei servizi più apprezzati e il numero di richieste cresce rapidamente. Nonostante, ed allo stesso tempo, a causa delle informazioni disponibili online, esigenze di informazione degli utenti diventano sempre più internazionali e diversificate. Inoltre, a causa della immediata disponibilità di molti prodotti on-line, le aspettative degli utenti sono di un rapido accesso al full text. Per soddisfare queste esigenze ed aspettative, i bibliotecari americani hanno sviluppato diversi strumenti per ottimizzare i flussi di lavoro che comprendono, a più livelli, la condivisione delle risorse: ne sono esempi ILLiad e il software Odyssey, Direct Request feature, Purchase on Demand and Standalone Scanning Workstation, etc. Il futuro dell’ILL deve però tener conto di importanti realtà, come il diritto d’autore e le licenze per la gestione delle risorse elettroniche. Tuttavia, se le biblioteche potranno prendere l’iniziativa ed intervenire sulle modifiche tecniche future, si potrà creare un ambiente più favorevole ai bibliotecari ed agli utenti e consentirci di compiere al meglio la nostra missione.Interlibrary Loan service in the U.S. academic libraries is one of the most demanded services and its demand grow up rapidly in recent decades. Despite, and at the same time, because of the information available online, patrons’ information needs become more international and diverse. In addition, due to the instant nature of many online products, patrons’ expectations for fast fulfillment of their request grow up rapidly. To satisfy the needs and expectations, U.S. ILL librarians implement various tools and workflows which include, multi-tiered resource sharing network, ILLiad and Odyssey software, Direct Request feature, Purchase on Demand and Standalone Scanning Workstation, etc. The future of ILL is not without serious challenges such as copyrights and electronic resources license. However, if libraries can take the initiative on technical changes and its future direction, we can create an environment more favorable for us to fulfill our mission

Constraining superheavy dark matter model of UHECR with SUGAR data

Models which associate the origin of the ultra-high energy cosmic rays (UHECR) with decays of relic superheavy particles predict the anisotropy of UHECR flux toward the Galactic center. We use the existing SUGAR data, which covered the Galactic center best so far, to look for such a signal and limit the fraction of UHECR produced by this mechanism. The absence of anisotropy toward the Galactic center in the SUGAR data implies at 95% confidence level that the fraction of SHDM-related cosmic rays should be less than 20% at $E>1\times10^{19}$ eV and less than 50% at $E>4\times10^{19}$ eV.Comment: 10 pages, 12 figure

Cultivation of algal biofuel feedstock in desert area of southern Nevada using municipal wastewater (NVREC project 1.3)

The second annual Nevada Renewable Energy Consortium meeting took place at UNLV on August 20. The meeting focused on the current three NVREC program areas: Solar, Biomass and Geothermal. Presentations were made by participating entities and a poster session followed

Robust Estimation of Operational Risk

According to the Loss Distribution Approach, the operational risk of a bank is determined as 99.9% quantile of the respective loss distribution, covering unexpected severe events. The 99.9% quantile can be considered a tail event. As supported by the Pickands-Balkema-de Haan Theorem, tail events exceeding some high threshold are usually modeled by a Generalized Pareto Distribution (GPD). Estimation of GPD tail quantiles is not a trivial task, in particular if one takes into account the heavy tails of this distribution, the possibility of singular outliers, and, moreover, the fact that data is usually pooled among several sources. Moreover, if, as is frequently the case, operational losses are pooled anonymously, relevance of the fitting data for the respective bank is not self-evident. In such situations, robust methods may provide stable estimates when classical methods already fail. In this paper, optimally-robust procedures MBRE, OMSE, RMXE are introduced to the application domain of operational risk. We apply these procedures to parameter estimation of a GPD at data from Algorithmics Inc. To better understand these results, we provide supportive diagnostic plots adjusted for this context: influence plots, outlyingness plots, and QQ plots with robust confidence bands.Comment: 14 pages, 5 figure

Development Of A Software-based Tool For Factory Communication Structure Evaluation In The Context Of Industry 4.0

The environment of manufacturing companies is constantly changing. Industry 4.0 as an overarching contemporary trend constantly places new demands on production technology. But Industry 4.0 does not only have new requirements to the production technology, but also to the communication in factories. The capacity for innovation and thus the success of companies is significantly influenced by the effective communication between the employees. Therefore, it is necessary that companies systematically adapt their communication structures according to these communication requirements. This paper addresses this aspect, by developing a method and a software-based tool which should allow the mentioned adjustment. The aim is to enable companies in the manufacturing sector to record and evaluate their communication structures at low cost. Furthermore, they should be able to derive effective measures efficiently through the developed method and to use them for their individual needs

Extending the Real-Time Maude Semantics of Ptolemy to Hierarchical DE Models

This paper extends our Real-Time Maude formalization of the semantics of flat Ptolemy II discrete-event (DE) models to hierarchical models, including modal models. This is a challenging task that requires combining synchronous fixed-point computations with hierarchical structure. The synthesis of a Real-Time Maude verification model from a Ptolemy II DE model, and the formal verification of the synthesized model in Real-Time Maude, have been integrated into Ptolemy II, enabling a model-engineering process that combines the convenience of Ptolemy II DE modeling and simulation with formal verification in Real-Time Maude.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

Definition, reporting, and interpretation of composite outcomes in clinical trials: systematic review

Objective To study how composite outcomes, which have combined several components into a single measure, are defined, reported, and interpreted

Strategies for stable water splitting via protected photoelectrodes

This review provides a comprehensive overview of the key aspects of protection strategies for achieving stable solid/liquid interfaces for photoelectrodes.</p