IEEE Transactions on Industrial Informatics

Abstract - In this paper, a model of LAN traffic is presented. In the model, the most important components influencing the network traffic are taken into account. Namely, the transmission protocols and information buffering, operating systems, and queuing algorithms as well as user behavior in network applications are considered. The model is based on an “on-off” function. The network traffic observed at the physical layer is a superposition of many sequential and self-similar “on-off” processes. It has been shown that the self-similarity of the traffic, measured by the Hurst parameter, changes from almost 1.0 for very low frequencies to 0.5 for high frequencies .

Abstract - There is a growing trend in developing the wireless machine-to-machine (M2M) communication for factory automation. Currently, most wireless protocols for infrastructureless mobile ad-hoc networks focus on the mobility issue and are mainly suitable for narrowband radio devices. The mechanisms for route update and discovery that work well for wireless mobile ad-hoc networks prove to be redundant and instead add to processing overheads in a static wireless factory setting. This paper presents the development and implementation of a new wireless routing protocol, Bluewave, that caters specifically to wireless communication between machines in a factory setting. Bluewave utilizes features of Bluetooth technology when performing the route setup. The merits of the proposed protocol, in terms of shorter initialization time and route setup time, are duly discussed. A case study illustrating the application of Bluewave to an online condition-based maintenance scenario is presented. Experimental results obtained are furnished to show the viability of Bluewave in industrial automation.

3. "Performance Analysis of a Real-Time Control Network Test Bed in a Linux-Based System With Sporadic Message Arrivals"

Abstract - This paper describes the results from a real-time network test bed for a Linux-based control system with event-driven message traffic. Interest has grown in the use of Linux as a cost-effective alternative to expensive proprietary real-time operating systems. However, kernel tasks in Linux can cause random delays in message transmissions. Event-driven traffic can result in unpredictable message inter-arrival rates. Nondeterministic delays in message transmissions and sporadic message arrival times complicate the design of the network as they require the use of an estimation technique to analyze feasibility. Random temporal behavior can lead to network overloads, where it becomes unavoidable that some messages will be late. We discuss the design and feasibility analysis for the network and evaluate the network's performance in the presence of random kernel delay and sporadic message arrivals. Three message scheduling approaches are evaluated using different Linux configurations at different levels of network loading.

Abstract - Current and emerging safety-critical applications such as the automotive X-by-wire systems require a high degree of reliability. These dependable embedded distributed systems require an ultra-reliable communication system to exchange data between the distributed components. In addition to guaranteeing a high level of reliability, these communication systems should facilitate the development of fault-tolerant applications. This can be achieved by providing additional communication system services such as interactive consistency. Interactive consistency on a communication system can be defined as a means to ensure that all non-faulty nodes on the communication system receive a consistent value for any message communicated. This paper describes the adoption of an explicit interactive consistency algorithm on a time-triggered broadcast communication system, using a shared communication medium. This is supported by the development of a prototype implementation of the interactive consistency algorithm. This prototype system demonstrates that interactive consistency is successfully achieved in the presence of a number of faults.

Abstract - Upcoming car series will be deployed with time-triggered communication protocols due to benefits with respect to bandwidth, predictability, dependability, and system integration. In present day automotive networks, controller area network (CAN) is the most widely used communication protocol. Today, up to five CAN buses and several private CAN networks result from the bandwidth limits of CAN in conjunction with constraints concerning bus utilization aimed at controlling transmission latencies. In this context, the upcoming introduction of time-triggered networks into series production offers the potential to reduce the number of CAN networks by exploiting the high bandwidth of the time-triggered network instead of CAN buses. Due to the elimination of CAN buses, the resulting reduction of wiring and connectors promises a significant reduction in hardware cost and reliability improvements. In order to support the reuse of existing CAN-based application software, this paper presents a solution for the emulation of a CAN communication service on top of an underlying time-triggered network. By providing to CAN-based applications the same interface as in a conventional CAN system, redevelopment efforts for CAN-based legacy software are minimized. For this purpose, a CAN emulation middleware operates between a operating system and the CAN-based applications. In a first step, the middleware establishes event channels on top of the communication network in order to support on-demand transmission requests at <emphasis emphasistype="boldital">a priori </emphasis> unknown points in time. The middleware then emulates the carrier sense multiple access collision avoidance (CSMA/CA) media access protocol of a physical CAN network for passing messages received via event channels to the application in the correct temporal order. Finally, the application programming interface (API) of the widely used HIS/VectorCAN driver provides a handle-based programming interface with support for message filtering and callbacks. A validation setup with a time-triggered protocol (TTP) cluster demonstrates that the CAN emulation can handle CAN-based legacy software and a real-world communication matrix provided by the automotive industry

6. "Coordinating Agents in Shop Floor Environments From a Dynamic Systems Perspective"

Abstract - In this paper, we address agent coordination from a dynamic systems perspective and propose a dynamic coordination model, which is inspired by biological metabolic systems. A new coordination mechanism through dynamic local adjustment (CDLA) is presented, and coordination is achieved when every agent utilizes explicitly the global system dynamics and performs iteratively a dynamic local adjustment procedure. The CDLA mechanism is investigated in an example multiagent shop floor system. The results show that the example manufacturing process is well-coordinated and the coordination approach is practically applicable and effective .

7. "Service-Oriented Architecture for Distributed Publish/Subscribe Middleware in Electronics Production"

Abstract - The Computer Aided Manufacturing using XML (CAMX) framework enables integrating electronics production systems using message-oriented middleware, offering standards-based communication among machines and control software applications. CAMX frameworks implement publish/subscribe of XML messages through an entity called the message broker (MSB), which provides the messaging service using a web-based interface. A challenge for MSB-based systems is that they must scale to handle large volumes of messaging traffic, which is a characteristic of modern information-intensive manufacturing systems. This paper first tackles this challenge by presenting an array of architecture patterns for creating distributed MSB frameworks, focusing mainly on globally distributed federations and locally distributed clusters. A unified architecture is subsequently presented that leverages the different patterns by combining federated frameworks with locally distributed clusters into a unified set of architecture elements and interactions. A service-oriented approach is followed to provide a uniform interface for distributed MSB elements, whether federated or locally distributed. The service-oriented approach is also used to dynamically discover resources and automatically invoke the (re)configuration and messaging services. The services are enriched with semantics in order to facilitate automatic discovery and selection of services using the semantic web services formal ontology. Semantic service advertisements are propagated using a peer-to-peer discovery protocol. The approach presented in this paper is not limited to the CAMX case and is generally applicable to distributed event-based manufacturing systems.

Chou, M. C. Ye, H. Yuan, X.-M. Cheng, Y. N. Chua, L. Guam, Y. Lee, S. E. Tay, Y. C.

Abstract - In this paper, we study a software-focused products and service supply chain based on the practice of two leading electronic manufacturing services providers in the world and their major corporate clients. We discuss the common and unique issues that a software-focused supply chain has compared with a traditional supply chain. We also indicate the research challenges and opportunities for a software-focused supply chain.

Abstract - In today's competitive logistics business environment, airfreight forwarders need to optimize every aspect of their logistics operations. However, forwarders still heavily rely on human brain and working experiences for calculating complex cargo packing and scheduling problems. Although recent research studies related to cargo packing and scheduling problems have resulted in the development of a number of advanced techniques of cargo planning, it can be seen that most of the research work is focused on the optimization of space in order to achieve the maximum possible amount of cargo to be packed in the minimum of space. After numerous site evaluation and end-user feedbacks, it is found that space optimization does not necessarily cause profit optimization, which is the ultimate aim of logistics providers. A study of contemporary research publications indicates that there are inadequate research studies related to profit-based optimization in cargo packing areas. This paper presents a profit-based air cargo loading information system (ACLIS) that embeds an innovative technology known as heuristics iterative reasoning technology (HIRT) that supports loading plan generation, focusing on maximization of the profit margin. In general, the proposed system is meant to maximize the profit in the airfreight forwarding business. It adopts an objective function governed by a list of constraints together with rule-based reasoning to provide expert advice to support the generation of appropriate loading plans.

10. "Two-Stage Method for Synthesizing Liveness-Enforcing Supervisors for Flexible Manufacturing Systems Using Petri Nets"

Abstract - This paper develops a two-stage approach to synthesizing liveness-enforcing supervisors for flexible manufacturing systems (FMS) that can be modeled by a class of Petri nets. First, we find siphons that need to be controlled using a mixed integer programming (MIP) method. This way avoids complete siphon enumeration that is more time-consuming for a sizable plant model than the MIP method. Monitors are added for only those siphons that require them. Second, we rearrange the output arcs of the monitors on condition that liveness is still preserved. The liveness is verified by an MIP-based deadlock detection method instead of much time-consuming reachability analysis. Experimental studies show that the proposed approach is more efficient than the existing ones and can result in more permissive and structurally simpler liveness-enforcing supervisors than all the known existing methods. This paper makes the application of siphon-based deadlock control methods to industrial-size FMS possible.

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IEEE Industrial Electronics Society

IEEE Transactions on Industrial Informatics

Volume 2, Number 4, November 2006

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