Design for testability in hardware-software systems

Clearly, in today's complex systems, hardware and software approaches to DFT must work together to achieve a successful overall solution. The authors investigate existing and new concepts that may lead to a single design for test strategy in the futur

Dealing With Ambiguous and Fluctuating Requirements of Embedded System Development: A Case-Study

This paper presents the findings of a case study that investigates how developers and managers deal with ambiguous and fluctuating requirements during an embedded system development in a structured process management environment. In particular, this paper focuses on improvisation and bricolage actions as a coping strategy by software developers and managers. This research adopts an interpretive approach that involves the collection and analysis of qualitative data. In this study, we observed a turbulent environment with situated improvisational and bricolage responses from developers and managers. The organizational structured process management framework was not sophisticated enough to deal with the existing challenges. Moreover, some improvisational and bricolage activities became institutionalized and, hence, became organizational routines of developers and managers. This paper indicates the value of reflexive practices as vital issues for strategic conduct in the event that improvisational and bricolage activities were deployed as a coping strategy

Hybrid switching : converging packet and TDM flows in a single platform

Optical fibers have brought fast and reliable data transmission to today’s network. The immense fiber build-out over the last few years has generated a wide array of new access technologies, transport and network protocols, and next-generation services in the Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN). All these different technologies, protocols, and services were introduced to address particular telecommunication needs. To remain competitive in the market, the service providers must offer most of these services, while maintaining their own profitability. However, offering a large variety of equipment, protocols, and services posses a big challenge for service carriers because it requires a huge investment in different technology platforms, lots of training of staff, and the management of all these networks. In today’s network, service providers use SONET (Synchronous Optical NETwork) as a basic TDM (Time Division Multiplexing) transport network. SONET was primarily designed to carry voice traffic from telephone networks. However, with the explosion of traffic in the Internet, the same SONET based TDM network is optimized to support increasing demand for packet based Internet network services (data, voice, video, teleconference etc.) at access networks and LANs. Therefore the service providers need to support their Internet Protocol (IP) infrastructure as well as in the legacy telephony infrastructure. Supporting both TDM and packet services in the present condition needs multilayer operations which is complex, expensive, and difficult to manage. A hybrid switch is a novel architecture that combines packets (IP) and TDM switching in a unified access platform and provides seamless integration of access networks and LANs with MAN/WAN networks. The ability to fully integrate these two capabilities in a single chassis will allow service providers to deploy a more cost effective and flexible architecture that can support a variety of different services. This thesis develops a hybrid switch which is capable of offering bundled services for TDM switching and packet routing. This is done by dividing the switch’s bandwidth into VT1.5 (Virtual Tributary -1.5) channels and providing SONET based signaling for routing the data and controlling the switch’s resources. The switch is a TDM based architecture which allows each switch’s port to be independently configured for any mixture of packet and TDM traffic, including 100% packet and 100% TDM. This switch allows service providers to simplify their edge networks by consolidating the number of separate boxes needed to provide fast and reliable access. This switch also reduces the number of network management systems needed, and decreases the resources needed to install, provision and maintain the network because of its ability to “collapse” two network layers into one platform. The scope of this thesis includes system architecture, logic implementation, and verification testing, and performance evaluation of the hybrid switch. The architecture consists of ingress/egress ports, an arbiter and a crossbar. Data from ingress ports is carried to the egress ports via VT1.5 channels which are switched at the cross point of the crossbar. The crossbar setup and channel assignments at ingress port are done by the arbiter. The design was tested by simulation and the hardware cost was estimated. The performance results showed that the switch is non-blocking, provide differentiated service, and has an overall effective throughput of 80%. This result is a significant step towards the goal of building a switch that can support multiprotocol and provide different network capabilities into one platform. The long-term goal of this project is to develop a prototype of the hybrid switch with broadband capability

Real-Time Scheduling of Sensor and Actuator Networks

Real-time scheduling issues in sensor and actuator networks (SANs) was investigated. The research studies the real-time issues related to the interplay between acquisition of data from sensors, its use in controller development, and optimal, real-time task scheduling based on available computing resources. Real-time task scheduling with the goal of achieving optimal system performance was the focus. Task schedulability with higher task rates and resource efficiency was investigated. Consideration of task execution times less than the worst case execution times results in achieving higher task frequencies. The problem of handling overruns using local (a task overrun reduces only that particular task frequency) and global (a task overrun initiates reduction of all task frequencies) approaches was investigated. A bisection method is proposed that has the potential to achieve higher task rates and resource efficiency. A number of examples are used to illustrate the ideas and methods.Computer Science Departmen

Silicon firewall prototype

The Internet is a technological advance that provides access to information, and the ability to publish information, in revolutionary ways. There is also a major danger that provides the ability to corrupt and destroy information as well. When a computer is connected to the Internet, three things are put at risk: the data storage, the computing resources and the user’s reputation. In order to balance the advantages and risks, the contact between a computer and the Internet or the contact between different networks should be controlled carefully. A firewall is a form of protection that allows a network to connect to the Internet or to another network while maintaining a degree of security. The firewall is an effective type of network security, and in most situations, it is the most effective tool for doing that. With the availability of larger bandwidth, it is becoming more and more difficult for traditional software firewalls to function over a high-speed connection. In addition, the advances in network hardware technology, such as routers, and new applications of firewalls have caused the software firewall to be an impediment to high throughput. This network bottleneck leads to the requirement for new solutions to balance performance and security. Replacing software with hardware could lead to improved performance, enabling the firewalls to handle significantly larger amounts of data. The goal of this project is to investigate if and how existing desktop computer firewall technology could be improved by replacing software functionality with hardware (i.e., silicon). A hardware-based Silicon Firewall system has been designed by choosing the appropriate architecture and implemented using Altera FPGA (Field Programmable Gate Array) on a SOPC (System On a Programmable Chip) Board. The performance of the Silicon Firewall is tested and compared with the software firewall

Fuzzy decision making system and the dynamics of business games

Effective and efficient strategic decision making is the backbone for the success of a business organisation among its competitors in a particular industry. The results of these decision making processes determine whether the business will continue to survive or not. In this thesis, fuzzy logic (FL) concepts and game theory are being used to model strategic decision making processes in business organisations. We generally modelled competition by business organisations in industries as games where each business organization is a player. A player formulates his own decisions by making strategic moves based on uncertain information he has gained about the opponents. This information relates to prevailing market demand, cost of production, marketing, consolidation efforts and other business variables. This uncertain information is being modelled using the concept of fuzzy logic. In this thesis, simulation experiments were run and results obtained in six different settings. The first experiment addresses the payoff of the fuzzy player in a typical duopoly system. The second analyses payoff in an n-player game which was used to model a perfect market competition with many players. It is an extension of the two-player game of a duopoly market which we considered in the first experiment. The third experiment used and analysed real data of companies in a case study. Here, we chose the competition between Coca-cola and PepsiCo companies who are major players in the beverage industry. Data were extracted from their published financial statements to validate our experiment. In the fourth experiment, we modelled competition in business networks with uncertain information and varying level of connectivity. We varied the level of interconnections (connectivity) among business units in the business networks and investigated how missing links affect the payoffs of players on the networks. We used the fifth experiment to model business competition as games on boards with possible constraints or restrictions and varying level of connectivity on the boards. We also investigated this for games with uncertain information. We varied the level of interconnections (connectivity) among the nodes on the boards and investigated how these a ect the payoffs of players that played on the boards. We principally used these experiments to investigate how the level of availability of vital infrastructures (such as road networks) in a particular location or region affects profitability of businesses in that particular region. The sixth experiment contains simulations in which we introduced the fuzzy game approach to wage negotiation in managing employers and employees (unions) relationships. The scheme proposes how employers and employees (unions) can successfully manage the deadlocks that usually accompany wage negotiations. In all cases, fuzzy rules are constructed that symbolise various rules and strategic variables that firms take into consideration before taken decisions. The models also include learning procedures that enable the agents to optimize these fuzzy rules and their decision processes. This is the main contribution of the thesis: a set of fuzzy models that include learning, and can be used to improve decision making in business