Catálogo de publicaciones - libros

This paper introduces a web-based remote online equipment monitoring and diagnosis system incorporated with the wireless sensor network. The system architecture is discussed first, which is composed of wireless sensor nodes, wireless base stations, a host computer and some necessary intranet/Internet facilities that implements remote access to the sensory information, followed by the hardware and software design of the system. The wireless sensor network will implement the on-time data collection and wireless data-transmission from the spot, and the web-based software will perform the data display, malfunction diagnosis and some other tasks. Based on the results of the research, a tentative remote online monitoring system for an important blower fan in an iron and steel company is established and tested.

The Internet and e-commerce have helped transform economy into a prosperous New Economy. They are, and can continue to be, the nation’s high-octane engines of economic growth, productivity improvement and high-wage job-creation. The issue of online commerce and privacy is incredibly complex and does not lend itself to simplistic and premature legislative solutions. More education among policy makers needs to be undertaken to fully understand the impact of legislation and to avoid any unintended consequences that may follow. This paper present some new privacy principles and rules.

In this paper, we present an efficient method for supporting wireless video multicast services. The method is based on storing multiple differently encoded versions of the video stream at the server. The corresponding video streams are obtained by encoding the original uncompressed video file as a sequence of I-P(I) frames using different GOP pattern. Mechanisms for controlling the multicast service request are also presented and their effectiveness is assessed through simulations. Wireless multicast video services are supported with considerably reduced additional delay and acceptable visual quality at the wireless client –end.

Distributed Network Protocol Version 3 (DNP3) is an open and optimized protocol developed for the Supervisory Control and Data Acquisition (SCADA) Systems supporting the utilities industries. The DNP3 enables the Master Station to request data from Substations using pre-defined control function commands and Substations to respond by transmitting the requested data. DNP3 was never designed with security mechanisms in mind and therefore the protocol itself lacks any form of authentication or encryption. Discussion so far has been centered on two solutions to provide security for SCADA: cryptographic technologies placed at each end of the communication medium, or security enhancements placed directly in the protocol. This paper recommends a new Distributed Network Protocol Version 3 Security (DNPSec) framework to enable confidentiality, integrity, and authenticity placed directly in the DNP3. Such framework requires some modifications in the data structure of the DNP3 Data Link layer. Our main goal is to address the threats related to confidentiality, integrity, and authenticity in the DNP3 as part of SCADA architecture, with a minimum performance impact on the communication link; and without requiring modification to the much more expensive Master Station and Substation devices and the applications supporting them.

The present work offers a comparative study of Lagrangean relaxation in simple subgradient and space dilatation methods as applied to generalized assignment problems in diversity and capacity constraints (GAP-DC). This problem, which occurs when setting up a mobile telephone network, consists in attributing radio base stations to hubs at a minimal cost, so that the demands on each station and on the capacity of each hub can be met. The GAP-DC are known to be NP-hard. Computational results indicate that although simple subgradient algorithms are capable of producing good lower bounds, computational tests based on space dilatation methods resolve instances in less computational time as well as in the first iteration.

A module was developed to monitor and to control physical variables by means of mobile devices like a cellular telephone or PDA (Personal Digital Assistant). This one is made up of two parts: an application client accessible from a mobile device and an application Web in charge to manage requests of the application client. This last one, in interaction with the application Web via Internet, allows to visualize the state of the physical variables and to activate or to deactivate control systems with the purpose of altering one or more of these variables. The module was developed in the language OO Java combining platforms J2ME and J2EE for the application client and Web respectively. In addition the methodology of software engineering Un-method of the School of Systems of the National University of Colombia - Host Medellìn was used.

In line with the expansion of the Internet, the issue of information security has gained special importance. Many methods have been provided in order to establish hidden communications. In the meanwhile, steganography is one of a relatively new method. A method is introduced in this paper for exchanging information by steganography on HTML pages. The main idea in this method is to hide coded data in the ID attribute of the HTML document tags. Since numerous HTML pages are on the web, this method can be widely used. The suggested method is implemented by using the Java language.

The goal of admission control is to support the Quality of Service demands of real-time applications via resource reservation in IP networks. In this paper we introduce a novel Dynamic Admission Control (DAC) mechanism for IP networks. The DAC dynamically allocates network resources using the previous network pattern for each path and uses the dynamic admission algorithm to improve bandwidth utilization using bandwidth brokers. We evaluate the performance of the proposed mechanism through trace-driven simulation experiments in view point of blocking probability, throughput and normalized utilization.