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Static and dynamic source separation using nonnegative factorizations: A unified view
, Article IEEE Signal Processing Magazine ; Vol. 31, issue. 3 , 2014 , pp. 66-75 ; ISSN: 1053-5888 ; Fevotte, C ; Mysore, G. J ; Mohammadiha, N ; Hoffman, M ; Sharif University of Technology
Abstract
Source separation models that make use of nonnegativity in their parameters have been gaining increasing popularity in the last few years, spawning a significant number of publications on the topic. Although these techniques are conceptually similar to other matrix decompositions, they are surprisingly more effective in extracting perceptually meaningful sources from complex mixtures. In this article, we will examine the various methodologies and extensions that make up this family of approaches and present them under a unified framework. We will begin with a short description of the basic concepts and in the subsequent sections we will delve in more details and explore some of the latest...
A Z approach to formalization and validation of ORM models
, Article Communications in Computer and Information Science, 20 July 2011 through 22 July 2011 ; Volume 194 CCIS , July , 2011 , Pages 513-526 ; 18650929 (ISSN) ; 9783642226021 (ISBN) ; Mirian Hosseinabadi, S. H ; Springer ; Sharif University of Technology
2011
Abstract
In this paper we present a formal definition of the basic concepts and notations of Object Role Modeling (ORM) using the Z formal specification language. Most of ORM concepts such as object and relationship types, value types, objectification, reference schemes, sub-types, roles and constraints such as uniqueness, mandatory, cardinality, subset, equality, exclusive and ring constraints are specified formally. Population is specified as objects, relationships and roles instances. These are specified using Z axioms and diagram instances are specified using Z schemas. This would enable validation and reasoning on the formal properties of ORM diagrams such as detecting constraint contradictions...
Improvement and experimental validation of a multi-zone model for combustion and NO emissions in CNG fueled spark ignition engine
, Article Journal of Mechanical Science and Technology ; Volume 26, Issue 4 , 2012 , Pages 1205-1212 ; 1738494X (ISSN) ; Hannani, S. K ; Ebrahimi, R ; Sharif University of Technology
2012
Abstract
This article reports the experimental and theoretical results for a spark ignition engine working with compressed natural gas as a fuel. The theoretical part of this work uses a zero-dimensional, multi-zone combustion model in order to predict nitric oxide (NO) emission in a spark ignition (SI) engine. The basic concept of the model is the division of the burned gas into several distinct zones for taking into account the temperature stratification of the burned mixture during combustion. This is especially important for accurate NO emissions predictions, since NO formation is strongly temperature dependent. During combustion, 12 products are obtained by chemical equilibrium via Gibbs energy...