8 research outputs found
The Continuum Architecture: Towards Enabling Chaotic Ubiquitous Computing
Interactions in the style of the ubiquitous computing paradigm are possible today, but only in handcrafted environments within one administrative and technological realm. This thesis describes an architecture (called Continuum), a design that realises the architecture, and a proof-of-concept implementation that brings ubiquitous computing to chaotic environments. Essentially, Continuum enables an ecology at the edge of the network, between users, competing service providers from overlapping administrative domains, competing internet service providers, content providers, and software developers that want to add value to the user experience. Continuum makes the ubiquitous computing functionality orthogonal to other application logic. Existing web applications are augmented for ubiquitous computing with functionality that is dynamically compiled and injected by a middleware proxy into the web pages requested by a web browser at the user?s mobile device. This enables adaptability to environment variability, manageability without user involvement, and expansibility without changes to the mobile. The middleware manipulates self-contained software units with precise functionality (called frames), which help the user interact with contextual services in conjunction with the data to which they are attached. The middleware and frame design explicitly incorporates the possibility of discrepancies between the assumptions of ubiquitous-computing software developers and field realities: multiple administrative domains, unavailable service, unavailable software, and missing contextual information. A framework for discovery and authorisation addresses the chaos inherent to the paradigm through the notion of role assertions acquired dynamically by the user. Each assertion represents service access credentials and contains bootstrapping points for service discovery on behalf of the holding user. A proof-of-concept prototype validates the design, and implements several frames that demonstrate general functionality, including driving discovery queries over multiple service discovery protocols and making equivalences between service types, across discovery protocols
Agent-based resource management for grid computing
A computational grid is a hardware and software infrastructure that provides
dependable, consistent, pervasive, and inexpensive access to high-end
computational capability. An ideal grid environment should provide access to the
available resources in a seamless manner. Resource management is an important
infrastructural component of a grid computing environment. The overall aim of
resource management is to efficiently schedule applications that need to utilise the
available resources in the grid environment. Such goals within the high
performance community will rely on accurate performance prediction capabilities.
An existing toolkit, known as PACE (Performance Analysis and Characterisation
Environment), is used to provide quantitative data concerning the performance of
sophisticated applications running on high performance resources. In this thesis an
ASCI (Accelerated Strategic Computing Initiative) kernel application, Sweep3D,
is used to illustrate the PACE performance prediction capabilities. The validation
results show that a reasonable accuracy can be obtained, cross-platform
comparisons can be easily undertaken, and the process benefits from a rapid
evaluation time. While extremely well-suited for managing a locally distributed
multi-computer, the PACE functions do not map well onto a wide-area
environment, where heterogeneity, multiple administrative domains, and communication irregularities dramatically complicate the job of resource
management. Scalability and adaptability are two key challenges that must be
addressed.
In this thesis, an A4 (Agile Architecture and Autonomous Agents) methodology is
introduced for the development of large-scale distributed software systems with
highly dynamic behaviours. An agent is considered to be both a service provider
and a service requestor. Agents are organised into a hierarchy with service
advertisement and discovery capabilities. There are four main performance
metrics for an A4 system: service discovery speed, agent system efficiency,
workload balancing, and discovery success rate.
Coupling the A4 methodology with PACE functions, results in an Agent-based
Resource Management System (ARMS), which is implemented for grid
computing. The PACE functions supply accurate performance information (e. g.
execution time) as input to a local resource scheduler on the fly. At a meta-level,
agents advertise their service information and cooperate with each other to
discover available resources for grid-enabled applications. A Performance
Monitor and Advisor (PMA) is also developed in ARMS to optimise the
performance of the agent behaviours.
The PMA is capable of performance modelling and simulation about the agents in
ARMS and can be used to improve overall system performance. The PMA can
monitor agent behaviours in ARMS and reconfigure them with optimised
strategies, which include the use of ACTs (Agent Capability Tables), limited
service lifetime, limited scope for service advertisement and discovery, agent
mobility and service distribution, etc.
The main contribution of this work is that it provides a methodology and
prototype implementation of a grid Resource Management System (RMS). The
system includes a number of original features that cannot be found in existing
research solutions
A mid-level framework for independent network services configuration management
Tese doutoramento do Programa Doutoral em TelecomunicaçõesDecades of evolution in communication network’s resulted in a high diversity of solutions,
not only in terms of network elements but also in terms of the way they are managed.
From a management perspective, having heterogeneous elements was a feasible scenario
over the last decades, where management activities were mostly considered as additional
features. However, with the most recent advances on network technology, that includes
proposals for future Internet as well as requirements for automation, scale and efficiency,
new management methods are required and integrated network management became an
essential issue.
Most recent solutions aiming to integrate the management of heterogeneous network
elements, rely on the application of semantic data translations to obtain a common representation
between heterogeneous managed elements, thus enabling their management
integration. However, the realization of semantic translations is very complex to be effectively
achieved, requiring extensive processing of data to find equivalent representation,
besides requiring the administrator’s intervention to create and validate conversions,
since contemporary data models lack a formal semantic representation.
From these constrains a research question arose: Is it possible to integrate the con g-
uration management of heterogeneous network elements overcoming the use of manage-
ment translations? In this thesis the author uses a network service abstraction to propose
a framework for network service management, which comprehends the two essential management
operations: monitoring and configuring. This thesis focus on describing and
experimenting the subsystem responsible for the network services configurations management,
named Mid-level Network Service Configuration (MiNSC), being the thesis
most important contribution.
The MiNSC subsystem proposes a new configuration management interface for integrated
network service management based on standard technologies that includes an
universal information model implemented on unique data models. This overcomes the
use of management translations while providing advanced management functionalities,
only available in more advanced research projects, that includes scalability and resilience
improvement methods. Such functionalities are provided by using a two-layer distributed
architecture, as well as over-provisioning of network elements. To demonstrate MiNSC’s
management capabilities, a group of experiments was conducted, that included, configuration
deployment, instance migration and expansion using a DNS management system
as test bed. Since MiNSC represents a new architectural approach, with no direct reference for
a quantitative evaluation, a theoretical analysis was conducted in order to evaluate it
against important integrated network management perspectives. It was concluded that
there is a tendency to apply management translations, being the most straightforward solution
when integrating the management of heterogeneous management interfaces and/or
data models. However, management translations are very complex to be realized, being
its effectiveness questionable for highly heterogeneous environments. The implementation
of MiNSC’s standard configuration management interface provides a simplified
perspective that, by using universal configurations, removes translations from the management
system. Its distributed architecture uses independent/universal configurations
and over-provisioning of network elements to improve the service’s resilience and scalability,
enabling as well a more efficient resource management by dynamically allocating
resources as needed
Advances in Information Security and Privacy
With the recent pandemic emergency, many people are spending their days in smart working and have increased their use of digital resources for both work and entertainment. The result is that the amount of digital information handled online is dramatically increased, and we can observe a significant increase in the number of attacks, breaches, and hacks. This Special Issue aims to establish the state of the art in protecting information by mitigating information risks. This objective is reached by presenting both surveys on specific topics and original approaches and solutions to specific problems. In total, 16 papers have been published in this Special Issue