8,035 research outputs found

    CSP channels for CAN-bus connected embedded control systems

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    Closed loop control system typically contains multitude of sensors and actuators operated simultaneously. So they are parallel and distributed in its essence. But when mapping this parallelism to software, lot of obstacles concerning multithreading communication and synchronization issues arise. To overcome this problem, the CT kernel/library based on CSP algebra has been developed. This project (TES.5410) is about developing communication extension to the CT library to make it applicable in distributed systems. Since the library is tailored for control systems, properties and requirements of control systems are taken into special consideration. Applicability of existing middleware solutions is examined. A comparison of applicable fieldbus protocols is done in order to determine most suitable ones and CAN fieldbus is chosen to be first fieldbus used. Brief overview of CSP and existing CSP based libraries is given. Middleware architecture is proposed along with few novel ideas

    An overview of the planned CCAT software system

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    CCAT will be a 25m diameter sub-millimeter telescope capable of operating in the 0.2 to 2.1mm wavelength range. It will be located at an altitude of 5600m on Cerro Chajnantor in northern Chile near the ALMA site. The anticipated first generation instruments include large format (60,000 pixel) kinetic inductance detector (KID) cameras, a large format heterodyne array and a direct detection multi-object spectrometer. The paper describes the architecture of the CCAT software and the development strategy.Comment: 17 pages, 6 figures, to appear in Software and Cyberinfrastructure for Astronomy III, Chiozzi & Radziwill (eds), Proc. SPIE 9152, paper ID 9152-10

    Refining SCJ Mission Specifications into Parallel Handler Designs

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    Safety-Critical Java (SCJ) is a recent technology that restricts the execution and memory model of Java in such a way that applications can be statically analysed and certified for their real-time properties and safe use of memory. Our interest is in the development of comprehensive and sound techniques for the formal specification, refinement, design, and implementation of SCJ programs, using a correct-by-construction approach. As part of this work, we present here an account of laws and patterns that are of general use for the refinement of SCJ mission specifications into designs of parallel handlers used in the SCJ programming paradigm. Our notation is a combination of languages from the Circus family, supporting state-rich reactive models with the addition of class objects and real-time properties. Our work is a first step to elicit laws of programming for SCJ and fits into a refinement strategy that we have developed previously to derive SCJ programs.Comment: In Proceedings Refine 2013, arXiv:1305.563

    Firewall resistance to metaferography in network communications

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    In recent years corporations and other enterprises have seen a consolidation of security services on the network perimeter. Services that have traditionally been stand-alone, such as content filtering and antivirus scanning, are pushing their way to the edge and running on security gateways such as firewalls. As a result, firewalls have transitioned from devices that protect availability by preventing denial-of-service to devices that are also responsible for protecting the confidentiality and integrity of data. However, little, if any, practical research has been done on the ability of existing technical controls such as firewalls to detect and prevent covert channels. The experiment in this thesis has been designed to evaluate the effectiveness of firewalls—specifically application-layer firewalls—in detecting, correcting, and preventing covert channels. Several application-layer HTTP covert channel tools, including Wsh and CCTT (both storage channels), as well as Leaker/Recover (a timing channel), are tested using the 7-layer OSI Network Model as a framework for analysis. This thesis concludes that with a priori knowledge of the covert channel and proper signatures, application-layer firewalls can detect both storage and timing channels. Without a priori knowledge of the covert channel, either a heuristic-based or a behavioral-based detection technique would be required. In addition, this thesis demonstrates that application-layer firewalls inherently resist covert channels by adhering to strict type enforcement of RFC standards. This thesis also asserts that metaferography is a more appropriate term than covert channels to describe the study of “carried writing” since metaferography is consistent with the etymology and naming convention of the other main branches of information hiding—namely cryptography and steganography
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