Experimental Testbed System Research Articles

Enhancement of Signal Performance in bidirectional RSE-based CVLC system employing NPM modulation scheme

Abstract Camera-based visible light communication (CVLC) exploiting rolling shutter effect (RSE) is a cost-effective technique that ensures secure data transmission. In this paper, a bidirectional CVLC system is experimentally demonstrated using smartphone/laptop as downlink/uplink transceiver in an experimental prototype testbed. Meanwhile, a Nyquist pre-distorted Manchester (NPM) modulation scheme is proposed and validated in the experimental testbed system. The proposed scheme is based on low-complexity transmitter-side digital signal processing (DSP) techniques, Nyquist shaping and linear pre-distortion, which can be employed for mitigation of the impact of extinction ratio (ER) fluctuation and exposure overlapping in the RSE-based CVLC system. The experimental results show that by using the proposed NPM modulation, the uplink and the downlink can both achieve about 4.8 Kb/s transmission with bit error rate (BER) of below than 3.8e−3. It verifies the effectiveness of the proposed NPM scheme and the corresponding transmitter-side DSP techniques.

HOPSMAN: An Experimental Testbed System for a 10-Gb/s Optical Packet-Switched WDM Metro Ring Network

For future WDM MANs, optical packet-switching has been considered to be a promising paradigm that efficiently supports a wide range of Internet-based applications having time-varying and high bandwidth demands and stringent delay requirements. This article presents the design of an experimental testbed system for a high-performance optical packet-switched WDM metro ring network, HOPSMAN. HOPSMAN boasts three crucial features. First, it has a scalable architecture in which the number of nodes is unconstrained by the number of wavelengths. Second, HOPSMAN nodes are equipped with high-speed photonic hardware components, including fast tunable receivers and optical slot erasers, capable of performing speedy optical packet-switching operations. Third, HOPSMAN incorporates a MAC scheme that embodies efficient and dynamic bandwidth allocation, resulting in exceptional delay-throughput performance. The article presents the key hardware components by highlighting the challenging issues we faced and the solutions we proposed for the testbed implementation. Finally, to demonstrate the feasibility of HOPSMAN, the article describes the experimental setup and presents the results obtained from running a commercially available remote media player application on the system.

An interaction predictive approach to fault-tolerant control in network control systems

This paper illustrates some of the capabilities of previously proposed network control system (NCS) architectures to carry on functioning in the event of faults, without recourse to system reconfiguration. The principle of interaction prediction is used to set up a coordination strategy that encapsulates an ability to withstand or tolerate certain faults, thereby allowing the system to continue functioning. It is also shown that the coordination strategy can be made more effective if a learning agent is allowed to learn the coordination functions. This facilitates the use of different types of agent at the local level, together with recurrent networks and genetic algorithms (GAs) at the coordination level. The experimental test-bed system is a benchmark three-tank system that has some of the main features of an industrial process control system.

The design of co-audit: An experimental testbed system to support research on the next generation of audit technology

Abstract Accounting practitioners responsible for conducting audits of large, decentralized organizations face difficult issues including: (1) the decomposition of the auditing process in a manner conducive to organizations' decentralization strategies in such a way as to meet the level of global audit assurance that is required, (2) allocating audit specialists with appropriate levels of experience and knowledge to organizations' sites, and (3) synthesizing specialists' findings to achieve a global vantage point for rendering a comprehensive opinion. This paper addresses item three by describing the design of and our current progress in implementing CO-AUDIT, an experimental testbed system to enable various research agendas in support of developing the next generation of audit technology. As currently implemented the system provides an environment for investigating the sharability of knowledge and data, variables influencing group decision making, consensus building tools, structured auditing approaches, and communication between accounting practitioners engaged in the process of auditing large, decentralized organizations. In addition to addressing these aspects, CO-AUDIT has been designed to be sufficiently robust to facilitate inclusion of existing auditing-oriented knowledge based system applications. CO-AUDIT can be referred to as an experimental testbed system, developed to serve as a platform for facilitating future audit technology research.

An adhesive bond strength prediction algorithm based on ultrasonic signal analysis

Abstract The problem of predicting adhesive bond defects for both surface preparation and undercure defects has been studied using an ultrasonic, experimental test bed system. This experimental test bed incorporates the ultrasonic and computer equipment necessary to acquire and process data from various types of adhesively bonded test specimens. The computer hardware and software have been developed to allow the design of reliable pattern recognition algorithms for the evaluation of surface preparation and bond cure. The specific problem studied is the inspection of the adhesive bond in an aluminium/aluminium step-lap joint whose strength could be affected by improper surface preparation or undercure. A set of 164 bond specimens was used to design an algorithm that is 91% reliable for separating the specimens into a good class, those bonds with no defects, or a week class, bonds with poor surface preparation on an undercured adhesive layer. A Fisher Linear Discriminant function was selected by the test bed as the best pattern recognition routine for this classification problem.

An Ultrasonic Evaluation and Quality Control Tool for Adhesive Bonds

The problem of predicting adhesive bond performance for both surface preparation and undercure defects has been studied using an ultrasonic, experimental test bed system. This experimental test bed incorporates the ultrasonic and computer equipment necessary to acquire and process data from various types of adhesively bonded test specimens. The computer hardware and software has been developed to allow the design of reliable pattern recognition algorithms for the evaluation of surface preparation and bond cure. The specific problem studied is the inspection of the adhesive bond in an aluminum to aluminum step-lap joint whose strength could be affected by improper surface preparation or undercure. A set of 154 bond specimens was used to design an algorithm that is 91% reliable for separating the specimens into a good class, those bonds with no defects, or a weak class, bonds with poor surface preparation or undercured adhesive layer. A Fisher Linear Discriminant function was selected by the test bed as the...