February 1, 2006
1. "Semantic Web Services in Factory Automation: Fundamental Insights and Research Roadmap"
By Lastra, J.L.M.
Page(s): 1-11
Abstract - One of the significant challenges for current and future manufacturing systems is that of providing rapid reconfigurability in order to evolve and adapt to mass customization. This challenge is aggravated if new types of processes and components are introduced, as existing components are expected to interact with the novel entities but have no previous knowledge on how to collaborate. This statement not only applies to innovative processes and devices, but is also due to the impossibility to incorporate knowledge in a single device about all types of available system components. This paper proposes the use of Semantic Web Services in order to overcome this challenge. The use of ontologies and explicit semantics enable performing logical reasoning to infer sufficient knowledge on the classification of processes that machines offer, and on how to execute and compose those processes to carry out manufacturing orchestration autonomously. A series of motivating utilization scenarios are illustrated, and a research roadmap is presented.
2. "Network Architecture and Communication Modules for Guaranteeing Acceptable Control and Communication Performance for Networked Multi-Agent Systems"
By Lian, F.-L.; Yook, J.K.; Tilbury, D.M.; Moyne, J.
Page(s): 12-24
Abstract - When sensory and actuation devices in a control system are exchanging data through one common communication medium, the sharing of communication bandwidth will induce unavoidable data latency and might degrade the control performance. Hence, the utilization of communication resource and the requirement of control specification should be analyzed and properly designed when implementing a control system over a network architecture. In this paper, we analyze the performance of information sharing of multiple cooperative agents over one communication network, and propose design methodologies of guaranteeing acceptable control and communication performance in a networked control system. In particular, we study the relationship between the sampling rates of a control system, and the transmission rates of a communication network, and then utilize an integrated networked control design chart to help select design parameters and visualize overall system performance at different sampling and transmission rates. Based on the design parameters selected, the communication modules by utilizing deadband control and state estimation are presented for guaranteeing both control and communication performance. Simulation studies are conducted in a network-and-control simulation tool that is developed on the Matlab/Simulink platform and is used to demonstrate the proposed design methodologies. Both the analysis and simulation results illustrate the characteristics of designing mechanisms between control and communication performance and show the improvement of implementing the proposed communication modules.
3. "Timeliness of Real-Time IP Communication in Switched Industrial Ethernet Networks"
By Skeie, T.; Johannessen, S.; Holmeide, O.
Page(s): 25-39
Abstract - Through several giant evolutionary steps, Ethernet has become an almost ubiquitous technology for communication. Being versatile enough to be employed in new and various fields of application, it is now making inroads in factories. However, automated systems are different from many other applications of Ethernet, first and foremost because they require the network technology to deliver real-time performance. In the present study, a number of critical aspects of Ethernet, usually referred to as an Industrial Ethernet, are examined. More specifically, there is a focus on the application-to-application delay and jitter characteristics of such networks, when using Internet protocols such as UDP and TCP. It is demonstrated how important it is to take control of the latency in the station nodes, since the main communication delays occur inside the nodes, and different solutions are presented for controlling these delays. In particular, a priority-based protocol stack is assessed. The results show that real-time, Ethernet-based IP communication is now adequate even for demanding automated applications. In this paper, substation automation (power distribution) is used as an example of a demanding automation system.
4. "Energy-Efficient and Intrusion-Resilient Authentication for Ubiquitous Access to Factory Floor Information"
By Long, M.; Wu, C.-H.J.
Page(s): 40-47
Abstract - Linking factory floors to the Internet, coupled with the rapid deployment of wireless access networks, is initiating a new paradigm for factory automation-a corporate employee with a handheld computing device can have anytime, anywhere access to the latest factory floor information. Authentication between a factory database and a remote user is crucial for such paradigm; however, existing authentication protocols are inadequate to defend against strong adversaries with break-in capabilities. In this paper, we design and implement the Energy-Efficient and Intrusion-Resilient Authentication (ERA) protocol. Through a novel combination of hash chain, pin, and message authentication code (MAC), ERA can achieve the security self-recovery when strong adversaries compromise either a user's handheld device or a factory authentication server to obtain the authentication secrets. The technique of mutual MAC is proposed to defend against online pin-guessing attacks launched by strong adversaries. Furthermore, an optimization of tuning hash chain iteration is introduced to reduce energy consumption of a handheld device. Analytical and experimental results show that ERA provides a better security guarantee and incurs much less computation and communication overhead than the existing authentication protocols.
5. "Early Order Completion Contract Approach to Minimize the Impact of Demand Uncertainty on Supply Chains"
By Chan, H.K.; Chan, F.T.S.
Page(s): 48-58
Abstract - Many optimization techniques have been proposed over the years to improve the performance of supply chains. Although these approaches have been shown to be effective, most of them were developed without considering uncertainties in supply chains to simplify the analysis. In fact, uncertainties can deteriorate the performance of supply chains, such as increase in total cost, or drop in fill rate, of the whole system. In distributed supply chains, participating members are not under a sole control by a central authority, the problem is even more stringent due to incomplete information sharing, or so called asymmetrical information sharing. One way to improve the system performance is to achieve coordination among participating parties through establishment of contracts. The objectives of this paper are i) to evaluate the effects of demand uncertainty in a distributed supply chain, which is modelled as an agent-based system; ii) to propose a coordination mechanism with early order completion contract to minimize the negative impacts of demand uncertainty; and iii) to present associated simulation results. Performance of the system is measured in terms of costs and fill rate. Simulation results indicate that the proposed contract approach is able to improve the performance measures of the system.
6. "Web-Based Command Shaping of Cobra 600 Robot With a Swinging Load"
By Chang, T.; Jaroonsiriphan, P.; Bernhardt, M.; Ludden, P.
Page(s): 59-69
Abstract - This work focuses on the real-time control of a swinging load through the Internet. In particular, command shaping is applied to move a cable suspended load at the end point of an Adept Cobra 600 4-axis SCARA robot, with the objective of minimizing load swing. The first part of this paper discusses inverse kinematics, pendulum dynamics calculations, the corresponding shaping control algorithm, and the effects of transmission time delay. Standardized Internet interface via the DataSocket software in LabVIEW is then addressed in the second part. Simulation and experimental results confirm the feasibility of real time command shaping control through the Internet.