4,675 research outputs found

    An Advanced, Three-Dimensional Plotting Library for Astronomy

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    We present a new, three-dimensional (3D) plotting library with advanced features, and support for standard and enhanced display devices. The library - S2PLOT - is written in C and can be used by C, C++ and FORTRAN programs on GNU/Linux and Apple/OSX systems. S2PLOT draws objects in a 3D (x,y,z) Cartesian space and the user interactively controls how this space is rendered at run time. With a PGPLOT inspired interface, S2PLOT provides astronomers with elegant techniques for displaying and exploring 3D data sets directly from their program code, and the potential to use stereoscopic and dome display devices. The S2PLOT architecture supports dynamic geometry and can be used to plot time-evolving data sets, such as might be produced by simulation codes. In this paper, we introduce S2PLOT to the astronomical community, describe its potential applications, and present some example uses of the library.Comment: 12 pages, 10 eps figures (higher resolution versions available from http://astronomy.swin.edu.au/s2plot/paperfigures). The S2PLOT library is available for download from http://astronomy.swin.edu.au/s2plo

    A mechanized proof of loop freedom of the (untimed) AODV routing protocol

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    The Ad hoc On-demand Distance Vector (AODV) routing protocol allows the nodes in a Mobile Ad hoc Network (MANET) or a Wireless Mesh Network (WMN) to know where to forward data packets. Such a protocol is 'loop free' if it never leads to routing decisions that forward packets in circles. This paper describes the mechanization of an existing pen-and-paper proof of loop freedom of AODV in the interactive theorem prover Isabelle/HOL. The mechanization relies on a novel compositional approach for lifting invariants to networks of nodes. We exploit the mechanization to analyse several improvements of AODV and show that Isabelle/HOL can re-establish most proof obligations automatically and identify exactly the steps that are no longer valid.Comment: The Isabelle/HOL source files, and a full proof document, are available in the Archive of Formal Proofs, at http://afp.sourceforge.net/entries/AODV.shtm

    Mechanizing a Process Algebra for Network Protocols

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    This paper presents the mechanization of a process algebra for Mobile Ad hoc Networks and Wireless Mesh Networks, and the development of a compositional framework for proving invariant properties. Mechanizing the core process algebra in Isabelle/HOL is relatively standard, but its layered structure necessitates special treatment. The control states of reactive processes, such as nodes in a network, are modelled by terms of the process algebra. We propose a technique based on these terms to streamline proofs of inductive invariance. This is not sufficient, however, to state and prove invariants that relate states across multiple processes (entire networks). To this end, we propose a novel compositional technique for lifting global invariants stated at the level of individual nodes to networks of nodes.Comment: This paper is an extended version of arXiv:1407.3519. The Isabelle/HOL source files, and a full proof document, are available in the Archive of Formal Proofs, at http://afp.sourceforge.net/entries/AWN.shtm

    Data Compression System with a Minimum Time Delay Unit-Patent

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    Minimum time delay unit for conventional time multiplexed data compression channel

    Personhood and Respect for Life

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    The problem to be considered here centers on the question: What is a person? The way that we answer this question is very important in practical thinking, for all moral and legal problems involve persons. In particular, discussions of the morality of abortion require some definite view as to whether the fetus is in any sense a person. Indeed, we shall see that many contemporary issues concerning the right to live a full human life receive different solutions, depending on one\u27s view of what a person is. Many writers today, especially in the field of the social sciences, insist that human personality is something acquired in late infancy. They suggest that the human child comes to be a person when he begins to participate actively in his surrounding society. To be a person, in this sense, is to be engaged in socialization. This occurs, they say, at some point between the middle of the first year after birth and the end of the second year of infancy. Who started this way of looking at the human person, I do not know. However, some writers adopting this position refer to the writings of the anthropologist Ashley Montagu. In one of his semi-popular books he mentioned how “the Eskimos do not regard a baby as a complete human being until it is capable of sitting up.” At another place in the same book, Montagu apparently adopted the Eskimo view, for he now wrote that, “Human Nature is not what a man is born with, but what he becomes under the organizing influence of the socializing environment into which he is born.” In later writings Montagu has extended this social concept of the person to the domain of ethics. Now, what I propose to do is to examine this problem of the meaning of person not in any argumentative way but in the serious hope of throwing some light on contemporary disagreements concerning abortion and associated problems

    The Role of NGOs in the International Human Rights System: A Case Study—IJM in Thailand

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    International human rights have been codified in a number of declarations and conventions, but these rights are not always enforced. This paper will examine the right to citizenship and the other essential rights linked to it. When national governments are unable or refuse to grant citizenship to a group of people it results in a violation of international human rights norms. Non-governmental organizations (NGOs) play a key role in enforcing human rights standards in three ways: first, NGOs with lawyers on staff can work through national legal systems to ensure that rights, such as citizenship, are granted. Second, NGOs can bring human rights violations to the attention of the general public in order to pressure national governments to take action. Third, the human rights violations can be brought to the attention of international organizations such as the UN to put pressure on the offending nation. This paper will explore how International Justice Mission implemented all three of these measures in order to influence the Thai government to grant citizenship to the Karen people, a hill tribe in northern Thailand. International Justice Mission’s efforts were successful in bringing international attention to the plight of the Karen as well as navigating the Thai legal system to assist in the citizenship process

    Heinrich Albert Rommen (1897-1967);In Memoriam

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    Natural Law, Thomism - and Professor Neilsen;Note

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