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Effective image retrieval by content from database requires that visual image properties are used instead of textual labels to properly index and recover pictorial data. Retrieval by shape similarity, given a user-sketched template is particularly challenging, owing to the difficulty to derive a similarity measure that closely conforms to the common perception of similarity by humans. In this paper, we present a technique which is based on elastic matching of sketched templates over the shapes in the images to evaluate similarity ranks. The degree of matching achieved and the elastic deformation energy spent by the sketch to achieve such a match are used to derive a measure of similarity between the sketch and the images in the database and to rank images to be displayed. The elastic matching is integrated with arrangements to provide scale invariance and take into account spatial relationships between objects in multi-object queries. Examples from a prototype system are expounded with considerations about the effectiveness of the approach and comparative performance analysis. Index Terms - Image database, image retrieval by sketch, shape similarity-based retrieval, elastic matching.

Two distinct algorithms associated with packet filtering were studied to elucidate the bridges that interconnected Ethernet's local area network (LAN) to Fiber Distributed Data Interface (FDDI) backbones. The algorithm performance was compared with maximum Ethernet traffic and the rise in traffic generated on a local Ethernet. FDDI served as a backbone for lower-speed LAN's such as Token Ring and Ethernet.

The performance evaluation of transport protocols is a relevant step for designing efficient distributed applications. This analysis can be performed either with an unloaded medium or in the presence of background load. In this latter case, the effects of the interaction with other users are made evident, but remarkable difficulties exist to obtain a reproducible network load and to achieve accuracy in measurements. In this paper, performance measurements in the presence of background load are presented for TCP and UDP in the Internet family, and SPP and IDP in the Xerox Network System family. Experiments were carried out over an Ethernet LAN with MS-DOS AT-class stations.

In this paper we present a machine vision system to efficiently monitor, analyse and present visual data acquired from a railway overhead gantry equipped with multiple cameras. This solution aims to improve the safety of daily life railway transportation in a two-fold manner: (1) by estimating multiple safety requirements using image analysis algorithms that can process large imagery of trains (2) by helping train safety operators to detect any possible malfunction on a train. The system exploits high-rate visible and thermal cameras that observe a train passing under a railway overhead gantry. The machine vision system is composed of three principal modules: (1) an automatic wagon identification system, recognizing the wagon ID according to the UIC classification of railway coaches; (2) a system for the detection and localization of the pantograph of the train; (3) a temperature monitoring system. These three machine vision modules process batch trains sequences and their resulting analysis are presented to an operator using a multitouch user interface. [ABSTRACT FROM AUTHOR]