2,544 research outputs found

    Quantitative Verification: Formal Guarantees for Timeliness, Reliability and Performance

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    Computerised systems appear in almost all aspects of our daily lives, often in safety-critical scenarios such as embedded control systems in cars and aircraft or medical devices such as pacemakers and sensors. We are thus increasingly reliant on these systems working correctly, despite often operating in unpredictable or unreliable environments. Designers of such devices need ways to guarantee that they will operate in a reliable and efficient manner. Quantitative verification is a technique for analysing quantitative aspects of a system's design, such as timeliness, reliability or performance. It applies formal methods, based on a rigorous analysis of a mathematical model of the system, to automatically prove certain precisely specified properties, e.g. ``the airbag will always deploy within 20 milliseconds after a crash'' or ``the probability of both sensors failing simultaneously is less than 0.001''. The ability to formally guarantee quantitative properties of this kind is beneficial across a wide range of application domains. For example, in safety-critical systems, it may be essential to establish credible bounds on the probability with which certain failures or combinations of failures can occur. In embedded control systems, it is often important to comply with strict constraints on timing or resources. More generally, being able to derive guarantees on precisely specified levels of performance or efficiency is a valuable tool in the design of, for example, wireless networking protocols, robotic systems or power management algorithms, to name but a few. This report gives a short introduction to quantitative verification, focusing in particular on a widely used technique called model checking, and its generalisation to the analysis of quantitative aspects of a system such as timing, probabilistic behaviour or resource usage. The intended audience is industrial designers and developers of systems such as those highlighted above who could benefit from the application of quantitative verification,but lack expertise in formal verification or modelling

    Multidomain Network Based on Programmable Networks: Security Architecture

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    This paper proposes a generic security architecture designed for a multidomain and multiservice network based on programmable networks. The multiservice network allows users of an IP network to run programmable services using programmable nodes located in the architecture of the network. The programmable nodes execute codes to process active packets, which can carry user data and control information. The multiservice network model defined here considers the more pragmatic trends in programmable networks. In this scenario, new security risks that do not appear in traditional IP networks become visible. These new risks are as a result of the execution of code in the programmable nodes and the processing of the active packets. The proposed security architecture is based on symmetric cryptography in the critical process, combined with an efficient manner of distributing the symmetric keys. Another important contribution has been to scale the security architecture to a multidomain scenario in a single and efficient way.Publicad

    Fiber Coil Resonator for Optical Gain

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    We have developed a cheap design for a device using 3D printed parts and simple motors to fabricate a rare earth metal doped fiber coil amplifier. We also have measurements for bending losses in a small coil and absorption of the solar spectrum in an EDFA. This research will result in the creation of a design researchers can download, 3D print, and assemble to create their own fiber coils to whatever specifications are needed. These fabricated optical devices can be used for military laser defense systems, optical concentration such as solar concentrators, microfiber resonator coils or fiber coil gyroscopes. A rare earth metal doped fiber will be tightly wrapped around an acrylic tube with no gap between rings of the coil so that when the rings are epoxied together with a similar refractive index epoxy and removed from the glass tube, it creates an effective cylinder. Because this fiber is wrapped around in many windings, a long path is created for the signal wavelength to be amplified through while the device itself is compact enough to be portable and implemented in smaller areas. This will allow for very large gain in a device that is structured to take up little space in a small volume as opposed to a cumbersome great length in a fiber many meters long

    A Tale of Two Layers: Patents, Standardization, and the Internet

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    January 2019 Academic Affairs Minutes

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