Gal Lavee

Technion - Israel Institute of Technology, Computer Science, Researcher

Followers

Following

Co-authors

Public Views

Test Mail

Posts and Telecommunications Institute of Technology

Elisa Bertino

Purdue University

Elena Ferrari

Università degli Studi dell'Insubria

Ernesto Damiani

Università degli Studi di Milano - State University of Milan (Italy)

Carlo Bellettini

Università degli Studi di Milano - State University of Milan (Italy)

Dieter Gollmann

William R Cook

The University of Texas at Austin

Sushil Jajodia

George Mason University

pietro mazzoleni

IBM Research

Rajkumar Kannan

Bishop Heber College(Autonomous)

Interests

Uploads

Papers by Gal Lavee

Access control, confidentiality and privacy for video surveillance databases

Proceedings of the eleventh ACM symposium on Access control models and technologies - SACMAT '06, 2006

In this paper we have addressed confidentiality and privacy for video surveillance databases. Fir... more In this paper we have addressed confidentiality and privacy for video surveillance databases. First we discussed our overall approach for suspicious event detection. Next we discussed an access control model and accedes control algorithms for confidentiality. Finally we discuss privacy preserving video surveillance. Our goal is build a comprehensive system that can detect suspicious events, ensure confidentiality as well as privacy.

Download

Understanding Video Events: A Survey of Methods for Automatic Interpretation of Semantic Occurrences in Video

Ieee Transactions on Systems Man and Cybernetics Part C Applications and Reviews, Sep 1, 2009

Understanding Video Events, the translation of low-level content in video sequences into highleve... more Understanding Video Events, the translation of low-level content in video sequences into highlevel semantic concepts, is a research topic that has received much interest in recent years. Important applications of this work include smart surveillance systems, semantic video database indexing, and interactive systems. This technology can be applied to several video domains including: airport terminal, parking lot, traffic, subway stations, aerial surveillance, and sign language data. In this work we survey the two main components of the event understanding process: Abstraction and Event modeling. Abstraction is the process of molding the data into informative units to be used as input to the event model. Event modeling is devoted to describing events of interest formally and enabling recognition of these events as they occur in the video sequence. Event modeling can be further decomposed in the categories of Pattern Recognition Methods, State Event Models, and Semantic Event Models. In this survey we discuss this proposed taxonomy of the literature, offer a unifying terminology, and discuss popular abstraction schemes (e.g. Motion History Images) and event modeling formalisms (e.g. Hidden Markov Model) and their use in video event understanding using extensive examples from the literature. Finally we consider the application domain of video event understanding in light of the proposed taxonomy, and propose future directions for research in this field. 1

Download

Propagating Certainty in Petri Nets for Activity Recognition

Ieee Transactions on Circuits and Systems For Video Technology, Feb 1, 2013

ABSTRACT Petri Nets is a formalism that has recently been proposed for the specification of model... more ABSTRACT Petri Nets is a formalism that has recently been proposed for the specification of models for use in activity recognition . This formalism is attractive because of its inherent ability to model partial ordering, concurrency, logical and temporal relations between the events that compose activities. The main novelty of this work is a probabilistic mechanism (based on the particle filter) for recognizing activities modeled as Petri Nets in video. This mechanism takes into account the observation and semantic uncertainty inherent in low-level events and propagates it into a probabilistic activity recognition.

Building Petri Nets from Video Event Ontologies

Lecture Notes in Computer Science, 2007

Video event understanding requires a formalism that can model complex logical temporal and spatia... more Video event understanding requires a formalism that can model complex logical temporal and spatial relations between composing sub-events. In this paper we argue that the Petri-Net is such a formalism. We go on to define a methodology for constructing Petri-Net event models from semantic descriptions of events in two well known video event ontology standards, VERL and CASE E .

Download

A framework for a video analysis tool for suspicious event detection

Multimedia Tools and Applications, 2007

Abstract This paper proposes a framework to aid video analysts in detecting suspicious activity w... more

Understanding Video Events: A Survey of Methods for Automatic Interpretation of Semantic Occurrences in Video

IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews), 2000

Download

Video Event Modeling and Recognition in Generalized Stochastic Petri Nets

IEEE Transactions on Circuits and Systems for Video Technology, 2000

In this paper we propose the Surveillance Event Recognition Framework using Petri Nets (SERF-PN) ... more In this paper we propose the Surveillance Event Recognition Framework using Petri Nets (SERF-PN) for recognition of event occurrences in video based on the Petri Net(PN) formalism. This formalism allows us a robust way to express semantic knowledge about the event domain as well as efficient algorithms for recognizing events as they occur in a particular video sequence. The major novelties of this paper are extensions to both the modeling and the recognition capacities of Object PN paradigm. The first contribution of this work is the extension of the PN representational capacities by introducing stochastic timed transitions to allow modeling of events which have some variance in duration. These stochastic timed transitions sample the duration of the condition from a parametric distribution. The parameters of this distribution can be specified manually or learned from available video data. A second representational novelty of the paper is the use of a single PN to represent the entire event domain, as opposed to previous approaches which have utilized several networks, one for each event of interest. A third contribution of this work is the capacity to probabilistically predict future events by constructing a discrete time Markov chain model of transitions between states. The experiments section of the paper thoroughly evaluates the application of the SERF-PN framework in the event domains of surveillance and traffic monitoring and provides comparison to other approaches using the CAVIAR dataset, a standard

Download

Propagating Certainty in Petri Nets for Activity Recognition

IEEE Transactions on Circuits and Systems for Video Technology, 2000

Inverted index compression via online document routing

by Gal Lavee, Ronny Lempel, and Oren Somekh

Proceedings of the 20th international conference on World wide web - WWW '11, 2011

Modern search engines are expected to make documents searchable shortly after they appear on the ... more Modern search engines are expected to make documents searchable shortly after they appear on the ever changing Web. To satisfy this requirement, the Web is frequently crawled. Due to the sheer size of their indexes, search engines distribute the crawled documents among thousands of servers in a scheme called local index-partitioning, such that each server indexes only several million pages. To ensure documents from the same host (e.g., www.nytimes.com) are distributed uniformly over the servers, for load balancing purposes, random routing of documents to servers is common. To expedite the time documents become searchable after being crawled, documents may be simply appended to the existing index partitions. However, indexing by merely appending documents, results in larger index sizes since document reordering for index compactness is no longer performed. This, in turn, degrades search query processing performance which depends heavily on index sizes.

Download

Access control, confidentiality and privacy for video surveillance databases

Proceedings of the eleventh ACM symposium on Access control models and technologies - SACMAT '06, 2006

Download

Understanding Video Events: A Survey of Methods for Automatic Interpretation of Semantic Occurrences in Video

Ieee Transactions on Systems Man and Cybernetics Part C Applications and Reviews, Sep 1, 2009

Download

Propagating Certainty in Petri Nets for Activity Recognition

Ieee Transactions on Circuits and Systems For Video Technology, Feb 1, 2013