10,988 research outputs found

    Thermodynamics of Modified Cosmic Chaplygin Gas

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    In this paper, we examine the thermodynamic features of an exotic fluid known as modified cosmic Chaplygin gas in the context of homogeneous isotropic universe model. For this purpose, the behavior of physical parameters are discussed that help to analyze nature of the universe. Using specific heat formalism, the validity of third law of thermodynamics is checked. Furthermore, with the help of thermodynamic entities, the thermal equation of state is also discussed. The thermodynamic stability is explored by means of adiabatic, specific heat and isothermal conditions from classical thermodynamics. It is concluded that the considered fluid configuration is thermodynamically stable and expands adiabatically for an appropriate choice of parameters.Comment: 16 pages, 6 figures, to appear in AHE

    Efficient algorithms for dilated mappings of binary trees

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    The problem is addressed to find a 1-1 mapping of the vertices of a binary tree onto those of a target binary tree such that the son of a node on the first binary tree is mapped onto a descendent of the image of that node in the second binary tree. There are two natural measures of the cost of this mapping, namely the dilation cost, i.e., the maximum distance in the target binary tree between the images of vertices that are adjacent in the original tree. The other measure, expansion cost, is defined as the number of extra nodes/edges to be added to the target binary tree in order to ensure a 1-1 mapping. An efficient algorithm to find a mapping of one binary tree onto another is described. It is shown that it is possible to minimize one cost of mapping at the expense of the other. This problem arises when designing pipelined arithmetic logic units (ALU) for special purpose computers. The pipeline is composed of ALU chips connected in the form of a binary tree. The operands to the pipeline can be supplied to the leaf nodes of the binary tree which then process and pass the results up to their parents. The final result is available at the root. As each new application may require a distinct nesting of operations, it is useful to be able to find a good mapping of a new binary tree over existing ALU tree. Another problem arises if every distinct required binary tree is known beforehand. Here it is useful to hardwire the pipeline in the form of a minimal supertree that contains all required binary trees

    Investigating Evaluation Measures in Ant Colony Algorithms for Learning Decision Tree Classifiers

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    Ant-Tree-Miner is a decision tree induction algorithm that is based on the Ant Colony Optimization (ACO) meta- heuristic. Ant-Tree-Miner-M is a recently introduced extension of Ant-Tree-Miner that learns multi-tree classification models. A multi-tree model consists of multiple decision trees, one for each class value, where each class-based decision tree is responsible for discriminating between its class value and all other values present in the class domain (one vs. all). In this paper, we investigate the use of 10 different classification quality evaluation measures in Ant-Tree-Miner-M, which are used for both candidate model evaluation and model pruning. Our experimental results, using 40 popular benchmark datasets, identify several quality functions that substantially improve on the simple Accuracy quality function that was previously used in Ant-Tree-Miner-M

    Monetary policy restriction and dividend behavior of Pakistani firms: an empirical analysis

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    Studies upon impact of macro variables on firm’s dividend policy are very limited and specifically rare in Pakistan perspective. Main purpose of this research paper is to observe impact of restricted monetary policy on dividend behavior of Pakistani firms. During restricted monetary policy, cost of external funds increases and firms prefer to utilize internal funds leading to reduction in dividend payout. Behaviour of 100 listed firms, selected purposefully, has been observed for the period from 2001 to 2009 by using Lintner’ modified model.. During the research period of nine years, monetary policy has been gone through both loose and tight phases. Proposed model is dynamic one as lagged dependent variable has been used as explanatory variable. Due to certain limitations with selection of monetary policy instrument, overall stance of State Bank of Pakistan (SBP) in its annual reports has been used as a dummy variable in the model. Results of all the three estimations reveal almost same results. First lagged dividend has been proved to be most deterministic factor of dividend policy followed by current earnings. Monetary policy and lagged dividends interactive variables provide mixed results. First interactive variable has negative coefficients in all three, fixed effect, random effects and GMM, models but with insignificant p values. Second monetary policy interactive variable has positive coefficients with significant values in random effects and GMM model. Firms seem to follow relatively stable dividend policies with lower adjustment factor. As model is dynamic, GMM estimation is preferred. Monetary policy has not been observed as significant determinant of dividend policy of Pakistani firms.Dividend payment, Monetary Policy

    Efficient algorithms for a class of partitioning problems

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    The problem of optimally partitioning the modules of chain- or tree-like tasks over chain-structured or host-satellite multiple computer systems is addressed. This important class of problems includes many signal processing and industrial control applications. Prior research has resulted in a succession of faster exact and approximate algorithms for these problems. Polynomial exact and approximate algorithms are described for this class that are better than any of the previously reported algorithms. The approach is based on a preprocessing step that condenses the given chain or tree structured task into a monotonic chain or tree. The partitioning of this monotonic take can then be carried out using fast search techniques

    Can Higher Prices Stimulate Product Use? Evidence from a Field Experiment in Zambia

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    The controversy over whether and how much to charge for health products in the developing world rests, in part, on whether higher prices can increase use, either by targeting distribution to high-use households (a screening effect), or by stimulating use psychologically through a sunk-cost effect. We develop a methodology for separating these two effects. We implement the methodology in a field experiment in Zambia using door-to-door marketing of a home water purification solution. We find that higher prices screen out those who use the product less. By contrast, we find no consistent evidence of sunk-cost effects.

    Advancing the debate on architecture, planning, and built environment research

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    With an acceptance rate that does not exceed 25% of the total papers and articles submitted to the journal, IJAR – International Journal of Architectural Research is moving forward to position itself among the leading journals in architecture and urban studies worldwide. As this is the case since the beginning of volume 5, issue 1, March 2011, one must note that the journal has been covered by several data and index bases since its inception including Avery Index to Architectural Periodicals, EBSCO-Current Abstracts-Art and Architecture, INTUTE, Directory of Open Access Journals, Pro-Quest, Scopus-Elsevier and many university library databases across the globe. This is coupled with IJAR being an integral part of the archives and a featured collection of ArchNet and the Aga Khan Documentation Centre at MIT: Massachusetts Institute of Technology, Cambridge, MA. In 2014, IJAR was included in Quartile 2 / Q2 list of Journals both in ‘Architecture’ and ‘Urban Studies.’ As of May 2015, IJAR is ranked 23 out of 83 journals in ‘Architecture’ and 59 out of 119 in ‘Urban Studies.’ Rankings are based on the SJR (SCImago Journal Ranking); an Elsevier- SCOPUS indicator that measures the scientific influence of the average article in a journal. SJR is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. See here for more information (http://www.scimagojr.com/index.php) and (http://www.journalmetrics.com/sjr.php). While the journal is now on top of many of the distinguished journals in Elsevier- SCOPUS database, we will keep aspiring to sustain our position and move forward to Q1 group list and eventually in the top 10 journal list in the field. However, this requires sustained efforts and conscious endeavours that give attention to quality submissions through a rigorous review process. This edition of IJAR: volume 9, issue 2, July 2015 includes debates on a wide spectrum of issues, explorations and investigations in various settings. The issue encompasses sixteen papers addressing cities, settlements, and projects in Europe, South East Asia, and the Middle East. Papers involve international collaborations evidenced by joint contributions and come from scholars in universities, academic institutions, and practices in Belgium; Egypt; Greece; Italy; Jordan; Malaysia; Palestine; Qatar; Saudi Arabia; Serbia; Spain; Turkey; and the United Kingdom. In this editorial I briefly outline the key issues presented in these papers, which include topics relevant to social housing, multigenerational dwelling, practice-based research, sustainable design and biomimetic models, learning environments and learning styles, realism and the post modern condition, development and planning, urban identity, contemporary landscapes, and cultural values and traditions

    The concept of understanding in Jaspers and contemporary epistemology

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    In the General Psychopathology Jaspers famously draws a distinction between the understandable and explainable. Meaningful connections between psychic events, he argues, can only be understood empathetically and cannot be explained causally. The idea behind this distinction, according to some interpreters at least, seems to be that psychic events do not fall under any general causal rules whereas ordinary events do fall under such rules. Also Jaspers distinguishes empathetic understanding of the connection between two psychic events from a mere interpretation of it, which may turn out to be false. Hence, understanding seems to be able to give us the truth about the connection and is factive as well as self-evident in nature. Contemporary epistemologists, such as Linda Zagzebsky, Duncan Pritchard, and Jonathan Kvanvig, for example, distinguish three varieties: propositional, objectual or holistic, and atomistic understanding. They do not agree on factivity and transparency of understanding. What then is the difference between their views and that of Jaspers? This essay compares recent epistemological views of understanding with those of Jaspers and critiques his claims about empathetic understanding as being both factive and self-evident or transparent; to show that empathetic understanding of connections between psychic events needs a public criterion for its individuation

    Obituary : Thomas A. Dutton – Not a departure but a legacy of dialogic learning in architecture

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    At the end of September 2017, through an electronic circular from the Association of Architectural Educators, I came to know a few months late that Professor Thomas A. Dutton has passed away in June 2017. Died at an age of 65 years, with his departure as an influential educator, architect, and community enabler, a great void and a vacuum in architectural education as an academic discipline is created. A Cincinnati Professor of Community Engagement at Miami University, Oxford, Ohio, Tom left a legacy of body of writings, approaches to learning, fervent commitment, and, most important, countless professionals who, under his teachings, have acquired critical abilities to become agents of transformations of the communities they serve towards spatial justice and social impartiality. It is with great sadness that I write this Obituary for Tom Dutton. I reflect on my interaction with him in two occasions and present analytical contemplation on the design studio ideals he established
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