Papers by Catalin Calistru
The main challenges and issues of big data management
International Journal of Research Studies in Computing, 2013
Big data is a disruptive force that will affect organizations across industries, sectors and econ... more Big data is a disruptive force that will affect organizations across industries, sectors and economies. Through better analysis of the large volume of data that are becoming available, there is the potential for making faster advances in many scientific domains and improving the profitability of many enterprises. This paper examines the main challenges and issues that will have to be addressed to capture the full potential of big data. Additionally, we propose some initiatives and good practices that will help companies in the transition process for the big data analysis.
Proceedings of the 11th Wseas International Conference on Automatic Control Modelling and Simulation, 2009
The paper deals with PID robust control approaches based on integral` squared error criterion (IS... more The paper deals with PID robust control approaches based on integral` squared error criterion (ISE). The intelligent approaches, so called symbolic tune and genetic tune will lead to optimal controller parameters. Interesting examples obtained by simulation are presented.
Btw, 2007
Context-aware consumption of content implies that platforms mediating the access to content must ... more Context-aware consumption of content implies that platforms mediating the access to content must be able to do that independently of the user location, type of terminal, network conditions and content formats. In addition, user preferences, environmental conditions and content owners and usage rights should be respected. The fulfillment of this concept requires the availability of a comprehensive set of metadata related with both the content and the usage environment. But how can systems coherently and easily exchange, inter-relate and use the different types of required metainformation? This paper presents the solution developed within the ENTHRONE project with this aim, describing the mechanisms designed for publishing multimedia content and all relevant metadata associated with the consumption of that content, in an open and unified form, for accessing that content upon request of end-users and decide if and what kind of adaptation operations are needed to provide a context-aware service to the end user. The solution is based on the MPEG-21 standard and on the adoption of a modular and distributed architecture to implement the required functionality.
The wealth of multimedia items and their increasing complexity make data organization and search ... more The wealth of multimedia items and their increasing complexity make data organization and search essential. Without efficient storage, accurate search and informative retrieval it is hard to explore a multimedia repository to its full potential.
Plenary lecture 13: an insight to PENDULAR control
The plenary talk has in view to disseminate the author's original ideas concerning a particul... more The plenary talk has in view to disseminate the author's original ideas concerning a particular class of nonlinear control systems, so called PENDULAR Control Systems. These systems have an intuitive side as analyzed in the introductive section. PENDULAR is a mnemonic coming from Pendulum Efficiency with Nonlinear Dynamics and Unconventional Law in Achievement of Robustness. Also, in Romanian the verb "a pendula" defines the pendulum movement. PENDULAR control systems are referred by the mnemonic PCS. PCS are variable structure systems (VSS) with a simple structure. The main idea is to optimize conventional structures using a nonlinear element on the feedback loop. In fact, this nonlinear element produces changes in structure. So the 2nd section deals with it. The intuitive aspect of the two system substructures is treated in the 3rd section. In this section are presented some simulations in order to "feel" the PENDULAR concept. Since some of the simulations ...
Current multimedia applications require efficient tools for modeling and search. While solid mode... more Current multimedia applications require efficient tools for modeling and search. While solid models must support a large variety of concepts like sets, sub-sets, part-of hierarchies and integrate standards like Dublin Core, MPEG-7 (descriptors, descriptor schemes), TV-Anytime, MPEG-21 (digital item, digital item adaptation, digital item identification), the search algorithms must deal with heterogeneous multimedia data (text, image, audio and video). The search in audiovisual data requires the use of heterogeneous metadata representing a wide range of features, from low-level ones (color, motion) to high level ones (subject, mood), or domain-dependent concepts.
Lecture Notes in Computer Science, 2007
The paper presents a multimedia database model accounting for the representation of documents, co... more The paper presents a multimedia database model accounting for the representation of documents, collections and the associated metadata. Appropriate structures are provided for descriptive metadata and for metadata resulting from automatic content analysis. The model is based on the identification and unification of the main concepts in the archival standards and the audiovisual area.
A Historic Documentation Repository for Specialized and Public Access
Lecture Notes in Computer Science, 2007
Abstract. The web is currently the information searching and browsing environment of choice for s... more Abstract. The web is currently the information searching and browsing environment of choice for scholars and lay users alike. The goal of most cultural heritage applications is to interest a large audience, and therefore web interfaces are being developed even when part of ...
IEEE 6th Workshop on Multimedia Signal Processing, 2004., 2004
Multimedia databases are extending the scope of traditional databases to handle the complex struc... more Multimedia databases are extending the scope of traditional databases to handle the complex structure of multimedia objects. Models for multimedia information must include representations for the structure and content of several media in a form that allows flexibility in retrieval. Content-based retrieval is the main motivation behind recent research in multimedia databases. The task of searching in video and audio content is made hard by the nature of audiovisual data where, unlike text, there is no direct syntactic channel between the object and its meaning [1]-[3]. We propose a model for multimedia content storage and retrieval accounting for both context and content information and taking advantage of their dependencies for effective retrieval. We then describe a prototype multimedia database with a retrieval interface. It has been used as a workbench for testing the representation model and integrating tools for feature extraction, information interchange and retrieval. The workbench allows an easy integration of new tools for content analysis and new methods for context-and content-based retrieval while offering storage and access for both the actual digital content and its metadata.
A symbolic optimization approach for tuning of PID controllers
Proceedings of International Conference on Control Applications, 1995
ABSTRACT The paper presents an approach of tuning PID controllers using the integral criteria and... more ABSTRACT The paper presents an approach of tuning PID controllers using the integral criteria and symbolic calculus facilities offered by one of the most powerful symbolic calculus packages, MATHEMATICA. The approach, called SYMBOLIC-TUNE, considers the Krasovschii-Pospelov formulae. Different controller types and different plants are considered. Illustrative results obtain by simulation are presented
Lecture Notes in Computer Science, 2006
Multimedia retrieval brings new challenges, mainly derived from the mismatch between the level of... more Multimedia retrieval brings new challenges, mainly derived from the mismatch between the level of the user interactionhigh-level concepts, and that of the automatically processed descriptorslow-level features. The eective use of the low-level descriptors is therefore mandatory. Many data structures have been proposed for managing the representation of multidimensional descriptors, each geared toward efciency in some set of basic operations. The paper introduces a highly parametrizable structure called the BitMatrix, along with its search algorithms. The BitMatrix is compared with existing methods, all implemented in a common framework . The tests have been performed on two datasets, with parameters covering signicant ranges of values. The Bit-Matrix has proved to be a robust and exible structure that can compete with other methods for multidimensional descriptor indexing.
Multimedia - A Multidisciplinary Approach to Complex Issues, 2012
2007 IEEE 23rd International Conference on Data Engineering Workshop, 2007
Automatic multimedia retrieval requires the use of complex features, which are typically captured... more Automatic multimedia retrieval requires the use of complex features, which are typically captured by multidimensional descriptors. A basic operation in a multimedia retrieval system is similarity computation, making use of descriptor-dependant metrics. Many data structures have been proposed for managing the representation of multidimensional descriptors, each geared towards efficiency in some set of basic operations.
EURASIP Journal on Image and Video Processing, 2009
Cultural heritage documents are often subject to digitization processes resulting in image materi... more Cultural heritage documents are often subject to digitization processes resulting in image material, even for textual contents. It is therefore common, in collections of valuable documents, to have descriptive information generated by the institutions, along with digitized images, transcriptions created by scholars, translations and even miscellaneous annotations. To offer a faceted access to the collection it is necessary to explore these diverse materials, integrate them according to a model that accounts for both metadata and the content and provide a comprehensive retrieval environment. In this work we have applied the MetaMedia multimedia database framework to a collection of ancient documents, processed the documents in their descriptive, textual, and image content and produced a browsing and searching system. The main challenges are the integrated management of metadata and content, the indexing of the image content, and the design of the browsing and searching interface where various views on the data are kept together.
WSEAS Transactions on Systems
PID controllers have found extensive industrial applications for several decades. Recently, mixed... more PID controllers have found extensive industrial applications for several decades. Recently, mixed H 2 /H ∞ optimal control problems have received a great deal of attention from the viewpoint of theoretical design. Mixed H 2 /H ∞ control design approaches are useful for robust performance for systems under parameter perturbation and uncertain disturbance. In this paper, a design procedure is proposed to tune PID controller parameters to achieve mixed H 2 /H ∞ optimal performance. Since the criterion that must be optimized is of integral type, and the constraints are imposed by the robust control, the problem to be solved is a highly nonlinear minimization problem, in which many local minima may exist. Genetic algorithms are parallel, global search techniques that emulate natural genetic operators. Because a genetic algorithm simultaneously evaluates many points in the parameter space, it is more likely to converge to the global solution. MATHEMATICA is powerful symbolic calculus software, which also will be used in the paper to illustrate better the results. An illustrative example confirms that good performance can be achieved by the proposed method.
… Semantics-The role …, 2007
Context-aware consumption of content implies that platforms mediating the access to content must ... more Context-aware consumption of content implies that platforms mediating the access to content must be able to do that independently of the user location, type of terminal, network conditions and content formats. In addition, user preferences, environmental conditions and content owners and usage rights should be respected. The fulfillment of this concept requires the availability of a comprehensive set of metadata related with both the content and the usage environment. But how can systems coherently and easily exchange, inter-relate and use the different types of required metainformation? This paper presents the solution developed within the ENTHRONE project with this aim, describing the mechanisms designed for publishing multimedia content and all relevant metadata associated with the consumption of that content, in an open and unified form, for accessing that content upon request of end-users and decide if and what kind of adaptation operations are needed to provide a context-aware service to the end user. The solution is based on the MPEG-21 standard and on the adoption of a modular and distributed architecture to implement the required functionality.
INESC, Porto at TRECVID 2007: Automatic and Interactive Video Search
Symbolic to genetic tuning of PID controllers
2015 E-Health and Bioengineering Conference (EHB), 2015
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Papers by Catalin Calistru