642,267 research outputs found

    The Completeness: From Henkin's Proposition to Quantum Computer

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    The paper addresses Leon Hen.kin's proposition as a " lighthouse", which can elucidate a vast territory of knowledge uniformly: logic, set theory, information theory, and quantum mechanics: Two strategies to infinity are equally relevant for it is as universal and t hus complete as open and thus incomplete. Henkin's, Godel's, Robert Jeroslow's, and Hartley Rogers' proposition are reformulated so that both completeness and incompleteness to be unified and thus reduced as a joint property of infinity and of all infinite sets. However, only Henkin's proposition equivalent to an internal position to infinity is consistent . This can be retraced back to set theory and its axioms, where that of choice is a key. Quantum mechanics is forced to introduce infinity implicitly by Hilbert space, on which is founded its formalism. One can demonstrate that some essential properties of quantum information, entanglement, and quantum computer originate directly from infinity once it is involved in quantum mechanics. Thus, these phenomena can be elucidated as both complete and incomplete, after which choice is the border between them. A special kind of invariance to the axiom of choice shared by quantum mechanics is discussed to be involved that border between the completeness and incompleteness of infinity in a consistent way. The so-called paradox of Albert Einstein, Boris Podolsky, and Nathan Rosen is interpreted entirely in the same terms only of set theory. Quantum computer can demonstrate especially clearly the privilege of the internal position, or " observer'' , or "user" to infinity implied by Henkin's proposition as the only consistent ones as to infinity. An essential area of contemporary knowledge may be synthesized from a single viewpoint

    Distributing the Gains from Trade With Incomplete Information

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    We argue that the incomplete information which the government has about domestic agents means that tariffs become an optimal instrument to protect them from import competition. We solve for the optimal government policies. subject to the political constraint of ensuring Pareto gains from trade, the incentive compatibility constraint, and the government's budget constraint. We find that the optimal policies take the form of nonlinear tariffs, so that both buyers and sellers of the import face an effective price which exceeds its world level. We find that the tariffs are never complete, in the sense of bringing prices (or all individuals back to their initial level. Rather, it will always be possible to make some individuals strictly better off than at the initial prices, while ensuring that no persons are worse off.

    A mechanism for solving bargaining problems between risk averse players

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    We propose a mechanism for resolving bargaining problems.The mechanism allows two players to make a sequence of simultaneous propositions. At any step, as long as the players have not reached an agreement, they can choose to implement a lottery between the different propositions. In this aspect, the mechanism is similar to the so called final others arbitration. However, contrary to the existing scheme, our mechanism is not compulsory. The history of the negotiation process is recorded and players can refuse an offer and go back in the process to a previous step. This generates an evolving sequence of status-quo points and results in a sequence of equilibrium others of the two play-ers that gradually converge towards each other. Our model assumes nodiscounting and complete information. Rather than time preferences, the main incentive to reach an agreement under our mechanism comes from risk aversion. Players have an incentive to avoid the uncertainty related to the lotteries that occur when offers do not result in an agreement. Rather than incomplete information, the process gradualism is driven by the necessity to make step by step concessions in order to generate evolving threat points. We show that under this mechanism, the unique subgame perfect equilibrium that does not use weakly dominated strategies coincides with a well-known static solution concept, the Raiffa solution.bargaining theory ; Raiffa bargaining solution ;risk aversion ; final offers arbitration ; chilling effect ; gradualism

    CrimeBB: Enabling cybercrime research on underground forums at scale

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    Underground forums allow criminals to interact, exchange knowledge, and trade in products and services. They also provide a pathway into cybercrime, tempting the curious to join those already motivated to obtain easy money. Analysing these forums enables us to better understand the behaviours of offenders and pathways into crime. Prior research has been valuable, but limited by a reliance on datasets that are incomplete or outdated. More complete data, going back many years, allows for comprehensive research into the evolution of forums and their users. We describe CrimeBot, a crawler designed around the particular challenges of capturing data from underground forums. CrimeBot is used to update and maintain CrimeBB, a dataset of more than 48m posts made from 1m accounts in 4 different operational forums over a decade. This dataset presents a new opportunity for large-scale and longitudinal analysis using up-to-date information. We illustrate the potential by presenting a case study using CrimeBB, which analyses which activities lead new actors into engagement with cybercrime. CrimeBB is available to other academic researchers under a legal agreement, designed to prevent misuse and provide safeguards for ethical research

    A mechanism for solving bargaining problems between risk averse players

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    We propose a mechanism for resolving bargaining problems.The mechanism allows two players to make a sequence of simultaneous propositions. At any step, as long as the players have not reached an agreement, they can choose to implement a lottery between the different propositions. In this aspect, the mechanism is similar to the so called final others arbitration. However, contrary to the existing scheme, our mechanism is not compulsory. The history of the negotiation process is recorded and players can refuse an offer and go back in the process to a previous step. This generates an evolving sequence of status-quo points and results in a sequence of equilibrium others of the two play-ers that gradually converge towards each other. Our model assumes nodiscounting and complete information. Rather than time preferences, the main incentive to reach an agreement under our mechanism comes from risk aversion. Players have an incentive to avoid the uncertainty related to the lotteries that occur when offers do not result in an agreement. Rather than incomplete information, the process gradualism is driven by the necessity to make step by step concessions in order to generate evolving threat points. We show that under this mechanism, the unique subgame perfect equilibrium that does not use weakly dominated strategies coincides with a well-known static solution concept, the Raiffa solution

    SelfReformer: Self-Refined Network with Transformer for Salient Object Detection

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    The global and local contexts significantly contribute to the integrity of predictions in Salient Object Detection (SOD). Unfortunately, existing methods still struggle to generate complete predictions with fine details. There are two major problems in conventional approaches: first, for global context, high-level CNN-based encoder features cannot effectively catch long-range dependencies, resulting in incomplete predictions. Second, downsampling the ground truth to fit the size of predictions will introduce inaccuracy as the ground truth details are lost during interpolation or pooling. Thus, in this work, we developed a Transformer-based network and framed a supervised task for a branch to learn the global context information explicitly. Besides, we adopt Pixel Shuffle from Super-Resolution (SR) to reshape the predictions back to the size of ground truth instead of the reverse. Thus details in the ground truth are untouched. In addition, we developed a two-stage Context Refinement Module (CRM) to fuse global context and automatically locate and refine the local details in the predictions. The proposed network can guide and correct itself based on the global and local context generated, thus is named, Self-Refined Transformer (SelfReformer). Extensive experiments and evaluation results on five benchmark datasets demonstrate the outstanding performance of the network, and we achieved the state-of-the-art

    Jacob Marschak and the Cowles Approaches to the Theory of Money and Assets

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    Jacob Marschak shaped the emergence of monetary theory and portfolio choice at the Cowles Commission (which he directed from 1943 to 1948, but with which he was involved already from 1937) at the University of Chicago, where he was the doctoral teacher of Leonid Hurwicz, Harry Markowitz and Don Patinkin, and then from 1955 at the Cowles Foundation at Yale University, where he was a senior colleague of James Tobin until moving to UCLA in 1960. Marschak’s later attempts to clarify the concept of liquidity and to emphasize the role of new information for economic behavior date back as far as to his early experiences with hyperinflationary processes in the Northern Caucasus during the Russian Revolution. Marschak came to monetary theory with his 1922 Heidelberg doctoral dissertation on the quantity theory equation of exchange (published in 1924 as “Die Verkehrsgleichung”), and embedded monetary theory in a wider theory of asset market equilibrium in studies of “Money and the Theory of Assets” (1938), “Assets, Prices, and Monetary Theory” (with Helen Makower, 1938), “Role of Liquidity under Complete and Incomplete Information” (1949), “The Rationale of the Demand for Money and of ‘Money Illusion’” (1950), and “Monnaie et liquiditĂ© dans les modĂšles macroĂ©conomiques et microĂ©conomiques” (1955), as well as in Income, Employment and the Price Level (lectures Marschak gave at Chicago, edited by Fand and Markowitz, 1951). We examine Marschak’s analysis of money within a broader theory of asset market equilibrium and explore the relation of his work to the monetary and portfolio theories of his doctoral students Markowitz and Patinkin and his colleague Tobin and to the revival of the quantity theory of money by Milton Friedman, a University of Chicago colleague unsympathetic to the methodology of the Cowles Commission

    The effectiveness and satisfaction of web-based physiotherapy in people with spinal cord injury: a pilot randomised controlled trial

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    Study Design: Pilot randomised controlled trial. Objectives: The aims of this study were to evaluate the effectiveness and participant satisfaction of web-based physiotherapy for people with Spinal Cord Injury (SCI). Setting: Community patients of a national spinal injury unit in a university teaching hospital, Scotland, UK. Methods: Twenty-four participants were recruited and randomised to receive eight weeks of web-based physiotherapy (intervention), twice per week, or usual care (control). Individual exercise programmes were prescribed based upon participant’s abilities. The intervention was delivered via a website (www.webbasedphysio.com) and monitored and progressed remotely by the physiotherapist. Results: Participants logged on to the website an average of 1.4±0.8 times per week. Between-group differences, although not significant were more pronounced for the 6 minute walk test. Participants were positive about using web-based physiotherapy and stated they would be happy to use it again and would recommend it to others. Overall it was rated as either good or excellent. Conclusions: Web-based physiotherapy was feasible and acceptable for people with SCI. Participants achieved good compliance with the intervention, rated the programme highly and beneficial for health and well-being at various states post injury. The results of this study warrant further work with a more homogenous sample
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