182,493 research outputs found
Characterization of porous materials in compressed and uncompressed conditions using a three-microphones method
No full textConventional methods to evaluate the absorption coefficient of materials use either a large reverberation room or wave guides such as standing-wave tubes or impedance tubes. These last methods have recently been extended so that other material properties such as airflow resistivity can also be evaluated using the same tubes. An advantage of the impedance tubes is that they can also be used to measure the acoustical and non-acoustical properties when the materials are under compression. The current study investigates the differences between two-microphone systems and three-microphone systems, and assess both the absorption coefficient and the flow resistivity of porous materials such as rock wool and fibreglass in both compressed and uncompressed conditions. Finally, the results of the study are discussed
The acoustic research in the Department of Architectural Science Ryerson University
No full textThe building science laboratory in the Department of Architectural Science has capabilities to conduct research activities in the field of room acoustics and noise control. Four impedance tubes, with both two-microphone and three-microphone systems, are available to evaluate the absorption coefficient as well as a number of other material properties. A scale model wind tunnel is also available for source localization experiments. Detailed finite element modelling, through COMSOL, are used to predict acoustic performance of passive silencers, Helmholtz resonators as well as sound propagation in the available wind tunnels. Similarly, aero-acoustic simulations are also possible by using the software ACTRAN. Finally, auditorium and room acoustic researches are conducted through simulations as well as through in field measurements
Special issue: Canadian acoustics cities = Édition spéciale : Acoustique canadienne des villes
No full textRobust object tracking using local kernels and background information”-Jaideep
Full text linkABSTRACT The mean shift algorithm has been proved to be efficient for tracking 2D blobs through a video sequence. Even so, this algorithm has certain inherent disadvantages. In this paper, we propose a robust tracking algorithm which overcomes the drawbacks of global color histogram based tracking. We incorporate tracking based only on reliable colors by separating the object from its background. A fast yet robust model updation is employed to overcome illumination changes. This algorithm is computationally simple enough to be executed real time and was tested on several complex video sequences. The proposed technique could be easily extended to other tracking algorithms too
Separable GPL: Decidable Model Checking with More Non-Determinism
Full text linkGeneralized Probabilistic Logic (GPL) is a temporal logic, based on the modal mu-calculus, for specifying properties of branching probabilistic systems. We consider GPL over branching systems that also exhibit internal non-determinism under linear-time semantics (which is resolved by schedulers), and focus on the problem of finding the capacity (supremum probability over all schedulers) of a fuzzy formula. Model checking GPL is undecidable, in general, over such systems, and existing GPL model checking algorithms are limited to systems without internal non-determinism, or to checking non-recursive formulae. We define a subclass, called separable GPL, which includes recursive formulae and for which model checking is decidable. A large class of interesting and decidable problems, such as termination of 1-exit Recursive MDPs, reachability of Branching MDPs, and LTL model checking of MDPs, whose decidability has been studied independently, can be reduced to model checking separable GPL. Thus, GPL is widely applicable and, with a suitable extension of its semantics, yields a uniform framework for studying problems involving systems with non-deterministic and probabilistic behaviors
Inference in Probabilistic Logic Programs Using Lifted Explanations
Full text linkIn this paper, we consider the problem of lifted inference in the context of Prism-like probabilistic logic programming languages. Traditional inference in such languages involves the construction of an explanation graph for the query that treats each instance of a random variable separately. For many programs and queries, we observe that explanations can be summarized into substantially more compact structures introduced in this paper, called "lifted explanation graph". In contrast to existing lifted inference techniques, our method for constructing lifted explanations naturally generalizes existing methods for constructing explanation graphs. To compute probability of query answers, we solve recurrences generated from the lifted graphs. We show examples where the use of our technique reduces the asymptotic complexity of inference
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The Legacy of Alladi Ramakrishnan in the Mathematical Sciences
No full textIn the spirit of Alladi Ramakrishnan's profound interest and contributions to three fields of science -- Mathematics, Statistics, and Physics -- this volume contains invited surveys and research articles from prominent members of these communities who also knew Ramakrishnan personally and greatly respected his influence in these areas of science. Historical photos, telegrams, and biographical narratives of Alladi Ramakrishnan's illustrious career of special interest are included as well
Congruence Primes of the Kim-Ramakrishnan-Shahidi Lift
No full textapplication/pdfFor a primitive form f of weight k for SL2(Z), let KS(f) be the Kim-Ramakrishnan-Shahidi (K-R-S) lift of f to the space of cusp forms of weight det(k+1)circle times Sym(k-2) for Sp(2)(Z). Based on some working hypothesis, we propose a conjecture, which relates the ratio KS(f), KS(f)/(3) of the periods (Petersson norms) to the symmetric 6th L-value L(3k - 2, f, Sym(6)) of f. From this, we also propose that a prime ideal dividing the (conjectural) algebraic part L(3k - 2, f, Sym(6)) of L(3k - 2, f, Sym(6)) gives a congruence between the K-R-S lift and non-K-R-S lift, and test this conjecture numerically
Congruence Primes of the Kim-Ramakrishnan-Shahidi Lift
No full textapplication/pdfFor a primitive form f of weight k for SL2(Z), let KS(f) be the Kim-Ramakrishnan-Shahidi (K-R-S) lift of f to the space of cusp forms of weight det(k+1)circle times Sym(k-2) for Sp(2)(Z). Based on some working hypothesis, we propose a conjecture, which relates the ratio KS(f), KS(f)/(3) of the periods (Petersson norms) to the symmetric 6th L-value L(3k - 2, f, Sym(6)) of f. From this, we also propose that a prime ideal dividing the (conjectural) algebraic part L(3k - 2, f, Sym(6)) of L(3k - 2, f, Sym(6)) gives a congruence between the K-R-S lift and non-K-R-S lift, and test this conjecture numerically.journal articl
- …
