Algon: a framework for supporting comparison of distributed algorithm performance

Programmers often need to use distributed algorithms to add non-functional behaviour such as mutual exclusion, deadlock detection and termination, to a distributed application. They find the selection and implementation of these algorithms daunting. Consequently, they have no idea which algorithm will be best for their particular application. To address this difficulty the Algon framework provides a set of pre-coded distributed algorithms for programmers to choose from, and provides a special performance display tool to support choice between algorithms. The performance tool is discussed. The developer of a distributed application will be able to observe the performance of each of the available algorithms according to a set of of widely accepted and easily-understandable performance metrics and compare and contrast the behaviour of the algorithms to support an informed choice. The strength of the Algon framework is that it does not require a working knowledge of algorithmic theory or functionality in order for the developer to use the algorithms

A SURVIVABLE DISTRIBUTED DATABASE AGAINST BYZANTINE FAILURE

Distributed Database Systems have been very useful technologies in making a wide range of information available to users across the World. However, there are now growing security concerns, arising from the use of distributed systems, particularly the ones attached to critical systems. More than ever before, data in distributed databases are more susceptible to attacks, failures or accidents owing to advanced knowledge explosions in network and database technologies. The imperfection of the existing security mechanisms coupled with the heightened and growing concerns for intrusion, attack, compromise or even failure owing to Byzantine failure are also contributing factors. The importance of  survivable distributed databases in the face of byzantine failure, to other emerging technologies is the motivation for this research. Furthermore, It has been observed that most of the existing works on distributed database only dwelled on maintaining data integrity and availability in the face of attack. There exist few on availability or survibability of distributed databases owing to internal factors such as internal sabotage or storage defects. In this paper, an architecture for entrenching survivability of Distributed Databases occasioned by Byzantine failures is proposed. The proposed architecture concept is based on re-creating data on failing database server based on a set  threshold value.The proposed architecture is tested and found to be capable of improving probability of survivability in distributed database where it is implemented to  99.6%  from 99.2%.

Adaptation Space: Surviving Non-Maskable Failures

Some failures cannot be masked by redundancies, because an unanticipated situation occurred, because fault-tolerance measures were not adequate, or because there was a security breach (which is not amenable to replication). Applications that wish to continue to offer some service despite nonmaskable failure must adapt to the loss of resources. When numerous combinations of non-maskable failure modes are considered, the set of possible adaptations becomes complex. This paper presents adaptation spaces, a formalism for navigating among combinations of adaptations. An adaptation space describes a collection of possible adaptations of a software component or system, and provides a uniform way of viewing a group of alternative software adaptations. Adaptation spaces describe the different means for monitoring the conditions that different adaptations depend on, and the particular configurations through which an adaptive application navigate. Our goal is to use adaptation spaces to provide survivable services to applications despite non-maskable failures such as malicious attacks. We present the basic concepts concerning adaptation spaces, with examples. We then present a formal model for reasoning about and selecting alternative adaptations, allowing developers of survivable application to automate their system’s adaptive behavior

Consciosusness in Cognitive Architectures. A Principled Analysis of RCS, Soar and ACT-R

This report analyses the aplicability of the principles of consciousness developed in the ASys project to three of the most relevant cognitive architectures. This is done in relation to their aplicability to build integrated control systems and studying their support for general mechanisms of real-time consciousness.\ud To analyse these architectures the ASys Framework is employed. This is a conceptual framework based on an extension for cognitive autonomous systems of the General Systems Theory (GST).\ud A general qualitative evaluation criteria for cognitive architectures is established based upon: a) requirements for a cognitive architecture, b) the theoretical framework based on the GST and c) core design principles for integrated cognitive conscious control systems

ANALYZING STRUCTURED TEXT ENTITIES USING A CITIZEN ORIENTED APPLICATION

The concept of citizen oriented informatics application is presented in the context of the knowledge society. The differences between these applications and the traditional applications are highlighted. The diversity of problems the citizens has lead to a high diversity of application structures that is described in the paper. Usual applications are taken into discussion and comments are made on their citizen orientation. Quality standards for informatics applications are described. An application for the analysis of the structured entities is presented. The methods that were used to orientate it towards the citizens are described. The procedure for the score computing is described. The performance of the application measured by automatic means is analyzed. Performance improvements are discussed. Future work directions and improvements are discussed.citizen oriented applications, knowledge, analysis, structured text entities

Fragment Capture Simulation for MANPADS Test Arena Optimization

The assessment of aircraft survivability against explosive munitions is an expensive undertaking. Test articles for both aircraft and weapon are scarce due to their high costs, leading to a limited supply of test data. The development of newer, hopefully more effective weaponry and protection measures continues despite the short supply of test data. Therefore, test organizations need to explore methods for increasing the quality of test results while looking for ways to decrease the associated costs. This research focuses on the Man-Portable Air-Defense System (MANPADS) as the weapon of choice and live- re arena testing as the experimental data source. A simulation infrastructure is built and used to examine how to optimize the arena configuration to maximize the test information obtained. Several research questions are explored: measuring potential data quality, comparing arena designs, and improving arena configurations based on fragment pattern predictions

Object-oriented shipboard electric power system library

The objective of this thesis is to explore the powerful capabilities of using an object-oriented modeling language to model and simulate an all electric Naval Shipboard Power System. Modelica has been used to model and simulate the shipboard power system which acts as an alternative simulation tool. The shipboard system is developed using the concept of packages. Different components like the buck converter, inverter, and AC machines have been modeled as a part of the library to develop the power system. The shipboard system has been simulated as two decoupled systems, the AC and DC systems. This research further focuses on developing a networked protection system to detect and clear faults and protect the shipboard power system from complete breakdown. A discrete supervisory controller has been designed using Petri nets as part of the protection system to control the converters and clear faults. A communication network has also been modeled for communication. Two different case studies, the open circuit test, and short circuit test were performed to test the effectiveness of the protection system and the simulation results are presented. This thesis also gives an overview of different properties of Modelica along with its advantages over other simulation tools, a detailed survey of different types of object-oriented simulation tools available, a comparison of different power electronics simulation tools, and some of the previous work done in Modelica