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    Improving Speech Signal Models for Statistical Parametric Speech Synthesis

    , Ph.D. Dissertation Sharif University of Technology Khorram, Soheil (Author) ; Sameti, Hossein (Supervisor)
    Abstract
    Statistical parametric speech synthesis (SPSS) has dominated speech synthesis research area over the last decade, due to its remarkable advantages such as high intelligibility and flexibility. Decision tree-clustered context-dependent hidden semi-Markov models are typically used in SPSS to represent probability densities of acoustic features given contextual factors. This research addresses four major limitations of this decision tree-based structure: (a) The decision tree structure lacks adequate context generalization; (b) It is unable to express complex context dependencies; (c) Parameters generated from this structure represent sudden transitions between adjacent states; (e) This... 

    On a new formulation of microphenomena: Basic principles, stationary fields and beyond

    , Article Pramana - Journal of Physics ; Volume 76, Issue 6 , 2011 , Pages 843-873 ; 03044289 (ISSN) Shafiee, A ; Sharif University of Technology
    Abstract
    In a series of essays, beginning with this article, we are going to develop a new formulation of microphenomena based on the principles of reality and causality. The new theory provides us with a new depiction of microphenomena assuming a unified concept of information, matter and energy. So, we suppose that in a definite microphysical context (including other interacting particles), each particle is enfolded by a probability field whose existence is contingent on the existence of the particle, but it can locally affect the physical status of the particle in a context-dependent manner. The dynamics of the whole particle-field system obeys deterministic equations in a manner such that when... 

    Knowledge active forgetting: the forgotten side of knowledge management

    , Article PICMET 2009 - 2009 Portland International Conference on Management of Engineering and Technology, Portland, OR, 2 August 2009 through 6 August ; 2009 , Pages 1007-1018 ; 1890843202 (ISBN); 9781890843205 (ISBN) Rezazade Mehrizi, M. H ; Bagherzadeh Niri, M ; Rahimi, M ; Yarmand, H ; Sharif University of Technology
    2009
    Abstract
    As Gregory Bateson, the British social scientists, once said "You can't live without an eraser", the process of learning is not a unidirectional way toward accumulation of knowledge, rather, organizations should critically evaluate the value of their knowledge and if necessary, actively forget no-longer-useful knowledge. A brief review of related literature shows that the concept of knowledge active forgetting (KAF) is a crucial aspect of organizational learning and knowledge management. However, many aspects of this topic deserve more attention by researchers. The main gap in the literature seems to be related to the linkage between peculiar aspects of knowledge (such as stickiness, context... 

    Spatial error concealment: A novel exemplar-based approach using segmentation

    , Article Computers and Electrical Engineering ; Volume 35, Issue 4 , 2009 , Pages 536-548 ; 00457906 (ISSN) Ranjbar, M ; Kasaei, S ; Sharif University of Technology
    2009
    Abstract
    In this paper, the problem of spatial error concealment for real-time applications is addressed. The proposed method can be categorized in exemplar-based error concealment approaches. In this category, a patch of corrupted pixels are replaced by another patch of the image that contains correct pixels. For splitting the erroneous block to different patches, a novel context-dependent exemplar-based algorithm based on a previously proposed segmentation method is proposed. The capability of the proposed method for concealment in diverse image regions is depicted. Our detailed conducted experiments show that the proposed method outperforms the state-of-the-art spatial error concealment methods in... 

    Context-dependent acoustic modeling based on hidden maximum entropy model for statistical parametric speech synthesis

    , Article Eurasip Journal on Audio, Speech, and Music Processing ; Vol. 2014, Issue. 1 , 2014 ; ISSN: 1687-4714 Khorram, S ; Sameti, H ; Bahmaninezhad, F ; King, S ; Drugman, T ; Sharif University of Technology
    Abstract
    Decision tree-clustered context-dependent hidden semi-Markov models (HSMMs) are typically used in statistical parametric speech synthesis to represent probability densities of acoustic features given contextual factors. This paper addresses three major limitations of this decision tree-based structure: (i) The decision tree structure lacks adequate context generalization. (ii) It is unable to express complex context dependencies. (iii) Parameters generated from this structure represent sudden transitions between adjacent states. In order to alleviate the above limitations, many former papers applied multiple decision trees with an additive assumption over those trees. Similarly, the current... 

    A Buchi automata based model checking framework for reo connectors

    , Article Proceedings of the ACM Symposium on Applied Computing, 26 March 2012 through 30 March 2012 ; March , 2012 , Pages 1536-1543 ; 9781450308571 (ISBN) Keshishzadeh, S ; Izadi, M ; Movaghar, A ; Sharif University of Technology
    Abstract
    Reo is an exogenous coordination language for synchronizing components participating in a component-based system. In this paper we provide a verification framework for model checking of Reo connectors. The proposed framework applies an extension of Büchi automata as the operational semantic model for Reo connectors and a record-based extension of linear time temporal logic (LTL) for expressing properties. Several aspects of Reo connectors, specially synchronization, context dependencies and fairness constraints, are addressed by this model checker due to its supported underlying model. The main ideas behind this implementation are to introduce a symbolic representation for the main elements... 

    End-to-end speech recognition using lattice-free MMI

    , Article 19th Annual Conference of the International Speech Communication, INTERSPEECH 2018, 2 September 2018 through 6 September 2018 ; Volume 2018-September , 2018 , Pages 12-16 ; 2308457X (ISSN) Hadian, H ; Sameti, H ; Povey, D ; Khudanpur, S ; Sharif University of Technology
    International Speech Communication Association  2018
    Abstract
    We present our work on end-to-end training of acoustic models using the lattice-free maximum mutual information (LF-MMI) objective function in the context of hidden Markov models. By end-to-end training, we mean flat-start training of a single DNN in one stage without using any previously trained models, forced alignments, or building state-tying decision trees. We use full biphones to enable context-dependent modeling without trees, and show that our end-to-end LF-MMI approach can achieve comparable results to regular LF-MMI on well-known large vocabulary tasks. We also compare with other end-to-end methods such as CTC in character-based and lexicon-free settings and show 5 to 25 percent... 

    Automata based model checking for reo connectors

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 15 April 2009 through 17 April 2009 ; Volume 5961 LNCS , 2010 , Pages 260-275 ; 03029743 (ISSN) ; 3642116221 (ISBN) Bonsangue, M. M ; Izadi, M ; Sharif University of Technology
    Abstract
    Reo is a connector language for the exogenous composition and orchestration of components in a software system. An operational semantics of Reo connectors can be given in terms of Büchi automata over a suitable alphabet of records, capturing both synchronization and context dependency requirements. In this paper, we define an action based linear time temporal logic for expressing properties of Reo connectors. Formulas can be synthesized into Büchi automata representing Reo connectors, thus leading to an automata based model checking algorithm. By generalizing standard automata based model checking algorithms for linear time temporal logic, we give an efficient on-the-fly algorithm for the... 

    Modeling real-time coordination systems using timed Bchi automata

    , Article 2011 CSI International Symposium on Computer Science and Software Engineering, CSSE 2011, 15 June 2011 through 16 June 2011 ; June , 2011 , Pages 17-24 ; 9781612842073 (ISBN) Ahmadi Danesh, Z ; Izadi, M ; Sharif University of Technology
    2011
    Abstract
    Reo is an exogenous coordination language for synthesizing components participating in a component-based system. The notion of Bchi automaton over streams of records (BAR for short) is a proposed operational semantics for Reo that covers several aspects of coordination strategies such as synchronization, context dependencies and fairness constraints. In this paper and for the purpose of modeling real-time coordination systems specified by Reo, we present a timed version of BARs as the acceptors of timed streams of records. We show that timed BAR and its streams of records based semantics are more standard and also more expressive than timed constraint automaton which is the first proposed...