Helio Crestana Guardia

Helio Crestana Guardia
Universidade Federal de São Carlos | UFSCar · Departamento de Computação (DC)

Professor

About

28
Publications
2,472
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
133
Citations
Citations since 2016
6 Research Items
38 Citations
20162017201820192020202120220246810
20162017201820192020202120220246810
20162017201820192020202120220246810
20162017201820192020202120220246810

Publications

Publications (28)
Chapter
The ongoing implementation of the Internet of Things (IoT) is sharply increasing the number and variety of small devices on edge networks. Likewise, the attack opportunities for hostile agents also increases, requiring more effort from network administrators and strategies to detect and react to those threats. For a network security system to opera...
Conference Paper
Advances in ubiquitous computing and in the Internet of things (IoT) bring new challenges to access control systems, such as not having to rely on a centralized trusted party, and the ability to use contextual data. Such characteristics may be required to enable IoT services in smart homes and cities, and in electronic health systems. In these envi...
Article
Full-text available
The WAND processing strategy is a dynamic pruning algorithm designed for large scale Web search engines where fast response to queries is a critical service. The WAND is used to reduce the amount of computation by scoring only documents that may become part of the top‐k document results. In this paper, we present two parallel strategies for the WAN...
Conference Paper
This paper presents an organized set of variables that can aid intelligent privacy agents in predicting the best and necessary moments to interrupt users in order to give them control and awareness over their privacy, avoiding information overload or over choice.
Article
Full-text available
Several existing IP mobility solutions use invasive approaches, when adjustments in legacy protocols from the TCP/IP stack are necessary, or rely on specific network infrastructures. We devised an architecture to handle mobility using a Session-based Mobile Socket Layer (SMSL). With no need for software adaptation in the core of the network or adju...
Article
Full-text available
A multitude of overlay network projects are emerging today providing the Internet with advanced features its architecture did not naturally support (routing, naming, addressing, mobility and security). Numerous complex scenarios faced today such as mobile devices, multi-homing equipments and middleboxes were not envisioned on TCP/IP conception and...
Conference Paper
In the Web of Things, standard web technologies and protocols are used to represent and communicate with physical and virtual things. One challenge toward this vision is integrating things with different characteristics, protocols, interfaces and constraints while maintaining the simplicity and flexibility required for a variety of applications. In...
Conference Paper
Full-text available
The on demand access, provided by Next Gener-ation Networks (NGN), will allow users of mobile devices to choose from and connect to networks with no pre-established service contract. Besides signal strength, knowledge about different parameters of the available networks shall base the selection of the attachment point to use. No mechanism currently...
Conference Paper
Mobile communication devices often present different wireless network interfaces which allow users to access networked services from anywhere and at any time. Existing services, however, commonly require specific interfaces and infrastructure to operate, and often fail to convey different data flows to a device. Little context information is used i...
Conference Paper
The Session-based IP Mobility Support [1] is a general purpose socket-based API designed to create mobility-aware applications that do not break with transmission disruptions or delays. In this paper, we present and discuss the security support provided in order to deal with threats in the phases of closed session opening and suspended session reop...
Conference Paper
Full-text available
Current ubiquitous computing technologies provide access to customized, contextual, and location-based services. Device mobility, however, is frequently associated with communication delays, link disruptions due to signal loss, and changes in IP address. As a result, connection-oriented applications may fail and node location strategies should not...
Conference Paper
Full-text available
Mobile devices with two network interfaces(WiFi and 3G) are already commercially available. Point-to-point communications such as Infrared and Bluetooth are also readily used. In the near future, mobile phones will have several interfaces including satellite and new technologies such as Ultra wideband. Hence we must assume that such devices will be...
Conference Paper
Several solutions have been proposed for Mobility Management in the Internet, ranging from the Network to the Application Layer. Existing support for mobility management is designed to work either at the lower protocol layers (L2 and L3), at the upper layers (L4, L5), or even across layers. In this paper we consider handling the mobility from the p...
Article
The increasing number of portable devices enabled with wireless technology interfaces has motivated the development of different services to provide access to multimedia contents anywhere and at any time. Most existing services however are directed at a specific purpose, rely on the existence of an appropriate network infrastructure, impose high de...
Conference Paper
Full-text available
A huge effort has been applied on the study of wireless mesh networks (WMNs) over the last few years. As part of this effort the IEEE 802.16 standard for local and metropolitan area networks specifies a mesh mode of operation. Although several technical aspects of the physical and medium access layers of the standard have been studied, only few wor...
Chapter
Full-text available
As redes móveis (celular, 802.11, PAN) tem como objetivo aumentar a acessibilidade da rede aos usuários em movimento. É neste contexto que encontramos um meio de socializar e compartilhar informações (ex.: adolescentes trocando "torpedos"com fotos). Para esses grupos, as redes móveis tem uma função mais social. Extendendo essa noção, o objetivo des...
Conference Paper
TIPS (Transparent IP Sockets) is a wrapping implementation of specific functions of the BSD sockets API to provide support for transparent IP mobility at the application level. Implemented on top of the transport layer it allows UDP and TCP communications to be immune to both client and server terminal migration (single and double jump). Location i...
Article
TIPS (Transparent IP Sockets) is a wrapping for the main functions of the Berkeley Sockets API intended to provide transparent IP Mobility in the application code. Implemented on top of the Transport Layer and in User Space, TIPS allows Horizontal and Vertical Handoffs for both UDP transmissions and TCP connections, as well as client and server mig...
Article
Full-text available
Most scheduling algorithms for computational grids rely on an ap-plication model represented by a directed acyclic graph (DAG). Tasks are then selected for execution according to their processing and communication weights. The obtainment of DAGs for real applications, however, is not a simple quest. Many MPI programs present a cyclic communication...
Conference Paper
Sistemas multi-agentes devem oferecer recursos suficientes para que seus agentes possam interagir de maneira satisfatória e atingir seus objetivos. Um exemplo de recurso é um conjunto de dados armazenados em algum tipo de mecanismo de persistência, como um sistema gerenciador de banco de dados. O acesso a dados deve ser possível mesmo que eles este...
Conference Paper
Full-text available
Security is an important concern in providing the infrastructure for the implementation of general purpose computational grids. However, most grid implementations focus their security concerns in correctly authenticating users and hosts and in the communications among them. In most cases, application security is left to the underlying operating sys...
Conference Paper
We introduce the ProGrid system, an architecture for computational grids, whose communication and resource management infrastructure is used transparently by the applications. Unlike other grid approaches, either application-centric or system-centric, the model relies on the use of proxy servers to perform additional communications and authenticati...
Conference Paper
Full-text available
The Computational Grid concept allows for large-scale resource sharing. The implementation of Grid environments relies on the existence of a communications infrastructure and efficient resource management. Access control and secure communication are also required. Architectures to support Computational Grids can be developed in a variety of ways. T...
Conference Paper
Nowadays, there is an increasing demand for data warehousing systems, which are computational systems to support decision making based on information stored in a data warehouse. In order to provide such systems with high performance, a concurrent database system, called CDBS, has been proposed, CDBS integrates parallel database and warehousing tech...
Article
Full-text available
Security is an important concern in providing the infrastructure for the implementation of general purpose computational grids. However, most grid implementations focus their security concerns in correctly authenticating users and hosts and in the communications among them. In most cases, application security is left to the underlying operating sys...
Article
This paper presents the architecture of an integrated caching and prefetching mechanism for distributed parallel file systems. By combining techniques for efficient data placement in the cache and the appropriate anticipation of the data to be requested by the application the mechanism proposed aims to provide reduced I/O latency and higher through...

Network

Cited By