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Showing papers in "IEEE Transactions on Industrial Informatics in 2009"


Journal ArticleDOI
TL;DR: A SOA enhanced with real-time capabilities for industrial automation that allows for negotiation of the QoS requested by clients from Web services, and provides temporal encapsulation of individual activities.
Abstract: Industrial automation platforms are experiencing a paradigm shift. New technologies are making their way in the area, including embedded real-time systems, standard local area networks like Ethernet, Wi-Fi and ZigBee, IP-based communication protocols, standard service oriented architectures (SOAs) and Web services. An automation system will be composed of flexible autonomous components with plug & play functionality, self configuration and diagnostics, and autonomic local control that communicate through standard networking technologies. However, the introduction of these new technologies raises important problems that need to be properly solved, one of these being the need to support real-time and quality-of-service (QoS) for real-time applications. This paper describes a SOA enhanced with real-time capabilities for industrial automation. The proposed architecture allows for negotiation of the QoS requested by clients from Web services, and provides temporal encapsulation of individual activities. This way, it is possible to perform an a priori analysis of the temporal behavior of each service, and to avoid unwanted interference among them. After describing the architecture, experimental results gathered on a real implementation of the framework (which leverages a soft real-time scheduler for the Linux kernel) are presented, showing the effectiveness of the proposed solution. The experiments were performed on simple case studies designed in the context of industrial automation applications.

227 citations


Journal ArticleDOI
TL;DR: Experimental results show that EARQ is suitable for industrial applications, due to its capability for energy efficient, real-time, reliable communications.
Abstract: Wireless industrial sensor networks are wireless sensor networks which have been adapted to industrial applications. Most techniques for wireless sensor networks can be applied to wireless industrial sensor networks. However, for industrial applications of wireless industrial sensor networks, new requirements such as real-time, reliable delivery need to be considered. In this paper, we propose EARQ, which is a novel routing protocol for wireless industrial sensor networks. It provides real-time, reliable delivery of a packet, while considering energy awareness. In EARQ, a node estimates the energy cost, delay and reliability of a path to the sink node, based only on information from neighboring nodes. Then, it calculates the probability of selecting a path, using the estimates. When packet forwarding is required, it randomly selects the next node. A path with lower energy cost is likely to be selected, because the probability is inversely proportional to the energy cost to the sink node. To achieve real-time delivery, only paths that may deliver a packet in time are selected. To achieve reliability, it may send a redundant packet via an alternate path, but only if it is a source of a packet. Experimental results show that EARQ is suitable for industrial applications, due to its capability for energy efficient, real-time, reliable communications.

199 citations


Journal ArticleDOI
TL;DR: This paper proposes an adaptive staggered sleep protocol (ASLEEP) for efficient power management in wireless sensor networks targeted to periodic data acquisition that dynamically adjusts the sleep schedules of nodes to match the network demands, even in time-varying operating conditions.
Abstract: In recent years, the use of wireless sensor networks for industrial applications has rapidly increased. However, energy consumption still remains one of the main limitations of this technology. As communication typically accounts for the major power consumption, the activity of the transceiver should be minimized, in order to prolong the network lifetime. To this end, this paper proposes an adaptive staggered sleep protocol (ASLEEP) for efficient power management in wireless sensor networks targeted to periodic data acquisition. This protocol dynamically adjusts the sleep schedules of nodes to match the network demands, even in time-varying operating conditions. In addition, it does not require any a priori knowledge of the network topology or traffic pattern. ASLEEP has been extensively studied with simulation. The results obtained show that, under stationary conditions, the protocol effectively reduces the energy consumption of sensor nodes (by dynamically adjusting their duty-cycle to current needs) thus increasing significantly the network lifetime. With respect to similar nonadaptive solutions, it also reduces the average message latency and may increase the delivery ratio. Under time-varying conditions, the protocol is able to adapt the duty-cycle of single nodes to the new operating conditions, while keeping a consistent sleep schedule among sensor nodes. The results presented here are also confirmed by an experimental evaluation in a real testbed.

189 citations


Journal ArticleDOI
TL;DR: Simulation and comparison show that the proposed two-hop neighborhood information-based routing protocol has led to lower packet deadline miss ratio and higher energy efficiency than two existing popular schemes.
Abstract: A two-hop neighborhood information-based routing protocol is proposed for real-time wireless sensor networks. The approach of mapping packet deadline to a velocity is adopted as that in SPEED; however, our routing decision is made based on the novel two-hop velocity integrated with energy balancing mechanism. Initiative drop control is embedded to enhance energy utilization efficiency, while reducing packet deadline miss ratio. Simulation and comparison show that the new protocol has led to lower packet deadline miss ratio and higher energy efficiency than two existing popular schemes. The result has also indicated a promising direction in supporting real-time quality-of-service for wireless sensor networks.

156 citations


Journal ArticleDOI
TL;DR: A way of combining retransmissions with real-time worst-case scheduling analysis is presented that can offer both a high grade of reliability and hard real- time support in industrial applications with strict reliability and timing requirements.
Abstract: Increased mobility coupled with a possible reduction of cabling costs and deployment time makes wireless communication an attractive alternative for the automation industry and related application areas. Methods compensating for the high probability of bit errors accompanying wireless transmissions are, however, needed. This is predominantly important in industrial applications with strict reliability and timing requirements, which cannot be met by standard communication protocols as, e.g., TCP. In this paper, a way of combining retransmissions with real-time worst-case scheduling analysis is presented that can offer both a high grade of reliability and hard real-time support. The presented solution handles one or several retransmission attempts of erroneous data without jeopardizing already guaranteed delay bounds of other packets. A real-time analysis for a full-duplex, asymmetric link, utilizing the novel retransmission scheme and supporting both piggybacked and nonpiggybacked acknowledgments, is provided. A simulation study is presented that evaluates the performance of the retransmission scheme for bit-error rates typically experienced in wireless communication. The results clearly indicate a possible reduction of the message error rate by several orders of magnitude.

113 citations


Journal ArticleDOI
TL;DR: This paper proposes to compute probabilistic upper bounds for end-to-end delays on avionic flows with stochastic network calculus approach and simulation approach, developed in the context of an industrial AFDX network configuration.
Abstract: AFDX (Avionics Full DupleX Switched Ethernet, ARINC 664) developed for the Airbus A380 represents a major upgrade in both bandwidth and capability Its reliance on Ethernet technology helps to lower some implementation costs, but guaranteed service presents challenges for system designers An analysis of end-to-end transfer delays through the network is required in order to determine upper bounds In this paper, we propose to compute probabilistic upper bounds for end-to-end delays on avionic flows Such upper bounds can be exceeded with a given probability p, and are relevant in the context of avionics, where functions are designed to give accurate results even if they miss some frames The stochastic network calculus approach analytically determines a probabilistic upper bound, whereas the simulation approach gives an experimental upper bound The former may be used for new certification needs since it assures that the probability of exceeding the computed upper bound is not greater than p The latter closely approximates actual network behavior and can help to give some idea of the pessimism of the stochastic network calculus upper bound The two approaches have been developed in the context of an industrial AFDX network configuration

107 citations


Journal ArticleDOI
TL;DR: The proposed FUSSER (fuzzy spectral and spatial classifier) algorithm merges the spectral andatial features to obtain a combined feature vector that is able to better sample the properties of the nonferrous materials than the single pixel spectral features when applied to the construction of multivariate Gaussian distributions.
Abstract: Hyperspectral data allows the construction of more elaborate models to sample the properties of the nonferrous materials than the standard RGB color representation. In this paper, the nonferrous waste materials are studied as they cannot be sorted by classical procedures due to their color, weight and shape similarities. The experimental results presented in this paper reveal that factors such as the various levels of oxidization of the waste materials and the slight differences in their chemical composition preclude the use of the spectral features in a simplistic manner for robust material classification. To address these problems, the proposed FUSSER (fuzzy spectral and spatial classifier) algorithm detailed in this paper merges the spectral and spatial features to obtain a combined feature vector that is able to better sample the properties of the nonferrous materials than the single pixel spectral features when applied to the construction of multivariate Gaussian distributions. This approach allows the implementation of statistical region merging techniques in order to increase the performance of the classification process. To achieve an efficient implementation, the dimensionality of the hyperspectral data is reduced by constructing bio-inspired spectral fuzzy sets that minimize the amount of redundant information contained in adjacent hyperspectral bands. The experimental results indicate that the proposed algorithm increased the overall classification rate from 44% using RGB data up to 98% when the spectral-spatial features are used for nonferrous material classification.

106 citations


Journal ArticleDOI
TL;DR: This study seamlessly integrate the group-based security model with a traditional real-time scheduling algorithm, namely earliest deadline first (EDF), and designs and develops a security-aware EDF schedulability test.
Abstract: An increasing number of real-time applications like railway signaling control systems and medical electronics systems require high quality of security to assure confidentiality and integrity of information. Therefore, it is desirable and essential to fulfill security requirements in security-critical real-time systems. This paper addresses the issue of optimizing quality of security in real-time systems. To meet the needs of a wide variety of security requirements imposed by real-time systems, a group-based security service model is used in which the security services are partitioned into several groups depending on security types. While services within the same security group provide the identical type of security service, the services in the group can achieve different quality of security. Security services from a number of groups can be combined to deliver better quality of security. In this study, we seamlessly integrate the group-based security model with a traditional real-time scheduling algorithm, namely earliest deadline first (EDF). Moreover, we design and develop a security-aware EDF schedulability test. Given a set of real-time tasks with chosen security services, our scheduling scheme aims at optimizing the combined security value of the selected services while guaranteeing the schedulability of the real-time tasks. We study two approaches to solve the security-aware optimization problem. Experimental results show that the combined security values are substantially higher than those achieved by alternatives for real-time tasks without violating real-time constraints.

100 citations


Journal ArticleDOI
TL;DR: This paper provides a better understanding of cross-channel interference in co-located IEEE 802.15.4 industrial networks and proposes a general methodology for the assessment of IEEE IEEE.
Abstract: The characteristics of the IEEE 802.15.4 physical and medium access layers make such a protocol a suitable candidate to support communication between sensors and actuators in industrial environments. As industrial networks may comprise a large number of sensors and actuators and the delay increases with the increased number of nodes, a possible solution to keep the delay small is the use of multiple radio channels to implement different small low-latency communication cells. Although in IEEE 802.15.4 the radio channels do not overlap, recent literature showed that some interference may actually occur. This paper provides a better understanding of cross-channel interference in co-located IEEE 802.15.4 industrial networks and proposes a general methodology for the assessment of IEEE 802.15.4 performance under different cross-channel interference conditions. This methodology allows a network designer to perform on-site but accurate assessments and can be easily deployed in real industrial environments to perform measurements directly in the environment-under-test. A case study based on COTS IEEE 802.15.4 devices is presented to show how to apply our methodology to a real scenario and to discuss the results obtained with one or multiple interferers and varying some MAC level parameters.

99 citations


Journal ArticleDOI
TL;DR: H-NAMe, a very simple yet extremely efficient hidden-node avoidance mechanism for WSNs, is proposed and implemented and exhaustively tested using an experimental test-bed based on ldquooff-the-shelfrdquo technology, showing that it increases network throughput and transmission success probability up to twice the values obtained without it.
Abstract: Wireless sensor networks (WSNs) emerge as underlying infrastructures for new classes of large-scale networked embedded systems. However, WSNs system designers must fulfill the quality-of-service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments and extremely limited energy/computing/memory/communication node resources are major obstacles for satisfying QoS metrics such as reliability, timeliness, and system lifetime. The limited communication range of WSN nodes, link asymmetry, and the characteristics of the physical environment lead to a major source of QoS degradation in WSNs-the ldquohidden node problem.rdquo In wireless contention-based medium access control (MAC) protocols, when two nodes that are not visible to each other transmit to a third node that is visible to the former, there will be a collision-called hidden-node or blind collision. This problem greatly impacts network throughput, energy-efficiency and message transfer delays, and the problem dramatically increases with the number of nodes. This paper proposes H-NAMe, a very simple yet extremely efficient hidden-node avoidance mechanism for WSNs. H-NAMe relies on a grouping strategy that splits each cluster of a WSN into disjoint groups of non-hidden nodes that scales to multiple clusters via a cluster grouping strategy that guarantees no interference between overlapping clusters. Importantly, H-NAMe is instantiated in IEEE 802.15.4/ZigBee, which currently are the most widespread communication technologies for WSNs, with only minor add-ons and ensuring backward compatibility with their protocols standards. H-NAMe was implemented and exhaustively tested using an experimental test-bed based on ldquooff-the-shelfrdquo technology, showing that it increases network throughput and transmission success probability up to twice the values obtained without H-NAMe. H-NAMe effectiveness was also demonstrated in a target tracking application with mobile robots over a WSN deployment.

98 citations


Journal ArticleDOI
TL;DR: A formal decision software tool is provided to extract the dominant features enabling tool wear prediction based on a formal mathematical approach that selects dominant features using the singular value decomposition of real-time measurements from the sensors of an industrial cutting tool.
Abstract: Identification and prediction of a lifetime of industrial cutting tools using minimal sensors is crucial to reduce production costs and downtime in engineering systems. In this paper, we provide a formal decision software tool to extract the dominant features enabling tool wear prediction. This decision tool is based on a formal mathematical approach that selects dominant features using the singular value decomposition of real-time measurements from the sensors of an industrial cutting tool. Selection of dominant features is important, as retaining only essential features allows reduced signal processing or even reduction in the number of required sensors, which cuts costs. It is shown that the proposed method of dominant feature selection is optimal in the sense that it minimizes the least-squares estimation error. The identified dominant features are used with the recursive least squares (RLS) algorithm to identify parameters in forecasting the time series of cutting tool wear. Experimental results on an industrial high-speed milling machine show the effectiveness in predicting the tool wear using only the dominant features.

Journal ArticleDOI
TL;DR: By combining the simplex algorithm, the approximation approach, and a mechanism of genotype-phenotype-mutation-based binary particle swarm optimization (GPM-BPSO), a hybrid GPM- BPSO algorithm is being exploited to solve the VaR-FFLP, a two-stage fuzzy zero-one integer programming problem.
Abstract: Reducing risks in location decisions when coping with imprecise information is critical in supply chain management so as to increase competitiveness and profitability. In this paper, a two-stage fuzzy facility location problem with value-at-risk (VaR), called VaR-FFLP, is proposed, which results in a two-stage fuzzy zero-one integer programming problem. Some properties of the VaR-FFLP, including the value of perfect information (VPI), the value of fuzzy solution (VFS), and the bounds of the fuzzy solution, are discussed. Since the fuzzy parameters of the location problem are represented in the form of continuous fuzzy variables, the determination of VaR is inherently an infinite-dimensional optimization problem that cannot be solved analytically. Therefore, a method based on the discretization of the fuzzy variables is proposed to approximate the VaR. The approximation approach converts the original problem into a finite-dimensional optimization problem. A pertinent convergence theorem for the approximation approach is proved. Subsequently, by combining the simplex algorithm, the approximation approach, and a mechanism of genotype-phenotype-mutation-based binary particle swarm optimization (GPM-BPSO), a hybrid GPM-BPSO algorithm is being exploited to solve the VaR-FFLP. A numerical example illustrates the effectiveness of the hybrid GPM-BPSO algorithm and shows its enhanced performance in comparison with the results obtained by other approaches using genetic algorithm (GA), tabu search (TS), and Boolean BPSO (B-BPSO).

Journal ArticleDOI
TL;DR: This work introduced three building blocks as key components for a generic RTE system, these includes topology-based addressing, optimized datagram transfer, and synchronous scheduling.
Abstract: After the introduction of fieldbus technology, real-time Ethernet (RTE) systems now form the second generation of industrial communication systems (2G ICS). A lot of different approaches for RTEs appeared during the last years, most of them optimized for specific use cases or application domains. From a user's perspective, the transition from a proved fieldbus system to a RTE only makes sense, if multiple system properties are improved significantly in comparison to the state-of-the-art. In order to address such main requirements of machine builders, we introduced three building blocks as key components for a generic RTE system, these includes topology-based addressing, optimized datagram transfer, and synchronous scheduling.

Journal ArticleDOI
TL;DR: Previous work on stochastic analysis of response times for software tasks to controller area network messages is extended, then compose them with sampling delays to compute probability distributions of end-to-end latencies.
Abstract: Many automotive applications, including most of those developed for active safety and chassis systems, must comply with hard real-time deadlines, and are also sensitive to the average latency of the end-to-end computations from sensors to actuators. A characterization of the timing behavior of functions is used to estimate the quality of an architecture configuration in the early stages of architecture selection. In this paper, we extend previous work on stochastic analysis of response times for software tasks to controller area network messages, then compose them with sampling delays to compute probability distributions of end-to-end latencies. We present the results of the analysis on a realistic complex distributed automotive system. The distributions predicted by our method are very close to the probability of latency values measured on a simulated system. However, the faster computation time of the stochastic analysis is much better suited to the architecture exploration process, allowing a much larger number of configurations to be analyzed and evaluated.

Journal ArticleDOI
TL;DR: Two algorithms are proposed for the composition of QoS-aware service-based applications with temporal requirements: an exhaustive algorithm that computes the optimal service combination in terms of a figure of merit, suitable for offline composition; and an improved algorithm based on heuristics and partial figures of merit suitable for online composition.
Abstract: This paper presents a model for quality-of-service (QoS)-aware service composition in distributed systems with real-time and fault-tolerance requirements. This model can be applied in application domains like, for example, remote monitoring, control and surveillance. Classic approaches to real-time systems do not provide the flexibility and fault-tolerance required in new emerging environments that need to combine a high degree of dynamism with temporal predictability. Our approach addresses these new challenges by combining concepts from the service oriented paradigm and distributed real-time systems. We propose a concrete system model based on a holistic time-triggered-based approach for design and configuration. Based on this model, we propose two algorithms for the composition of QoS-aware service-based applications with temporal requirements: an exhaustive algorithm that computes the optimal service combination in terms of a figure of merit, suitable for offline composition; and an improved algorithm based on heuristics and partial figures of merit, suitable for online composition. Experimental results show that the latter reduces dramatically the number of combinations explored with a minimal degradation in the quality of the solution, making it feasible for online execution in dynamic environments.

Journal ArticleDOI
TL;DR: A resource-efficient agent platform was developed, which relies on established concepts of agent platforms, but modifies and supplements them accordingly, and is implemented in Java and in several C++ variants.
Abstract: Recently, distributed agents are increasingly adopted in automation control systems, where they are used for monitoring, data collection, fault diagnosis and control. However, existing agent platforms do not always fulfill the requirements of practical automation applications in respect of real-time properties and resource usage. Often, they offer a lot of functionality that is not necessary in automation and leads to significant overhead in respect of design effort and runtime resources. To meet the specific requirements of the automation domain, a resource-efficient agent platform was developed, which relies on established concepts of agent platforms, but modifies and supplements them accordingly. This platform is implemented in Java and in several C++ variants. This paper describes the architecture of the platform and discusses several performance issues. Results of various performance tests are presented in comparison to the established agent platform JADE. Finally, a practical use case is presented, where the platform is utilized to drive a hardware-in-the-loop emulation and testing environment.

Journal ArticleDOI
TL;DR: A dynamic topology management protocol is presented that surpasses the static approach introducing support for event-driven data transmissions and node joining at runtime and providing a novel adaptive technique for energy balancing among nodes to further increase network lifetime.
Abstract: Topology management protocols play an important role in WSNs, managing the sleep transitions of the nodes to make data transmissions occur in an energy-efficient way, thus prolonging network lifetime. However, classical topology management protocols are not suitable for real-time WSNs, as they may introduce unbounded delays. In a previous work, we presented a static topology management protocol specifically designed for real-time WSNs which is able to provide bounded delay and routing fidelity. This paper extends such work, presenting a dynamic topology management protocol that surpasses the static approach introducing support for event-driven data transmissions and node joining at runtime and providing a novel adaptive technique for energy balancing among nodes to further increase network lifetime. This paper provides a detailed description of the dynamic protocol and simulation results on network lifetime and routing performance with comparative assessments.

Journal ArticleDOI
TL;DR: Analytical and simulation results confirm that the proposed network architecture with traffic shaping is well-adapted for in-vehicle communication.
Abstract: In-vehicle communication has become complex and costly due to the growing number of automotive network systems applied for different data types. In this work, our previously proposed in-vehicle network architecture that is based on Internet protocol (IP) and full-duplex switched Ethernet (IP/Ethernet) is further investigated for real-time audio and video streaming. Quality-of-service (QoS) and resource usage are analyzed for selected IP/Ethernet-based network topologies. Traffic shaping is used to reduce the required network resources and consequently the cost. A novel traffic shaping algorithm is presented that outperforms other traffic shapers in terms of resource usage when applied to variable bit rate video sources in the proposed double star topology. In addition, a new architecture design is introduced for traffic shaper implementation in switches which operates on a per stream basis. Analytical and simulation results confirm that the proposed network architecture with traffic shaping is well-adapted for in-vehicle communication.

Journal ArticleDOI
TL;DR: A framework based on supervisory control theory (SCT) is proposed to assist the design of multi-modal control for discrete-event systems (DESs) by designing modes which are conceptualized by using multi-model approach.
Abstract: A framework based on supervisory control theory (SCT) is proposed to assist the design of multi-modal control for discrete-event systems (DESs). Our purpose handled modes which are conceptualized by using multi-model approach. Each mode represents a running part of the system, depending on the requirements to enforce and resources to activate. The resulted framework aims to design each mode independently first, and resolves conflicting connections between them secondly. The proposal carries out a formal way to build the final ready-to-use control laws. A flexible manufacturing system illustrates this approach.

Journal ArticleDOI
TL;DR: This paper presents an novel analytical approach to provide the worst-case response time for real-time tasks in multiprocessor systems with shared resources and supports realistic, event- or time-driven task activation schemes and allows to calculate tight bounds on the estimated system performance.
Abstract: As multiprocessor systems are increasingly used in automotive real-time environments, scheduling and synchronization analysis of these platforms receive growing attention Upcoming multicore ECUs allow the integration of previously separated functionality for body electronics or sensor fusion onto a single unit, and allow the parallelization of complex computations over multiple cores The application of multiple CPUs turns an ECU into a highly integrated ldquonetworked systemrdquo microcosm, in which complex interdependencies can be observed due to the use of shared resources even in partitioned scheduling To deliver predictable performance, resource arbitration protocols are required and have been proposed in literature This paper presents an novel analytical approach to provide the worst-case response time for real-time tasks in multiprocessor systems with shared resources The method supports realistic, event- or time-driven task activation schemes and allows to calculate tight bounds on the estimated system performance

Journal ArticleDOI
TL;DR: The fuzzy-genetic algorithm constructs the automatic fault detection system for monitoring aircraft behaviors and genetic algorithms are used to generate an optimal fuzzy rule set for the classifier.
Abstract: This paper applies an intelligent technique based on fuzzy-genetic algorithm for automatically detecting failures in aircraft. The fuzzy-genetic algorithm constructs the automatic fault detection system for monitoring aircraft behaviors. Fuzzy-based classifier is employed to estimates the time of occurrence and types of actuator failure. Genetic algorithms are used to generate an optimal fuzzy rule set for the classifier. The optimization capability of genetic algorithms provides an efficient and effective way to generate optimal fuzzy rules. Different types of actuator failure can be detected online by the fuzzy-genetic algorithm based automatic fault detection system. Simulations with different actuator failures of the nonlinear F-16 aircraft model are reported and discussed.

Journal ArticleDOI
TL;DR: This paper considers wireless extensions of Ethernet Powerlink, a very popular Real-Time Ethernet network, implemented by means of the IEEE 802.11 WLAN, and provides an analysis of the hybrid networks aimed at evaluating the most relevant performance indexes.
Abstract: The industrial communication scenario is experiencing the introduction of wireless networks at all levels of factory automation systems. The benefits deriving from such an innovation are manifold, even if wireless systems cannot be thought as a complete replacement of wired networks. Rather, they will be even more used in the near future to realize hybrid (wired/wireless) configurations. In particular, it is envisaged that wireless networks may be employed to implement extensions of (possibly already installed) wired systems. In this paper we consider wireless extensions of Ethernet Powerlink, a very popular Real-Time Ethernet network, implemented by means of the IEEE 802.11 WLAN. Specifically, we focus on a widespread network configuration and address two types of extensions based on, respectively, bridge and gateway devices. In the second part of the paper we provide an analysis of the hybrid networks aimed at evaluating the most relevant performance indexes. Since the reliability of wireless networks may represent a critical aspect, the analysis is carried out taking into account the presence of interference as well as fading in the wireless segment. The results we show, obtained from a theoretical analysis and validated by numerical simulations, allow to get some useful insights on the overall performance of the hybrid networks.

Journal ArticleDOI
TL;DR: A protocol for synchronization in a hierarchical real-time scheduling framework that can be used to facilitate seamless and predictable integration and isolation of AUTOSAR components that have been developed by different manufacturers is presented.
Abstract: We present a method that allows for integration of individually developed functions of software components into a predictable real-time system. The method has been designed to provide a lightweight mechanism that gives temporal firewalls between functions, preventing unpredictable side effects during function integration. The method maps well to the AUTOSAR (automotive open system architecture) software component model and can thus be used to facilitate seamless and predictable integration and isolation of AUTOSAR components that have been developed by different manufacturers. Specifically, this paper presents a protocol for synchronization in a hierarchical real-time scheduling framework. Using our protocol, a software component does not need to know, and is not dependent on, the timing behavior of software components belonging to other functions; even though they share mutually exclusive resources. In this paper, we also prove the correctness of our approach and evaluate its efficiency and cost in terms of system load in a vehicular context.

Journal ArticleDOI
TL;DR: This work presents and proves the correctness of algorithms that address the major issues that must be addressed in order to solve the problem of executing a collection of independently designed and validated task systems upon a common platform composed of a preemptive processor and additional shared resources.
Abstract: We study the problem of executing a collection of independently designed and validated task systems upon a common platform composed of a preemptive processor and additional shared resources. We present an abstract formulation of the problem and identify the major issues that must be addressed in order to solve this problem. We present and prove the correctness of algorithms that address these issues, and thereby obtain a design for an open real-time environment.

Journal ArticleDOI
TL;DR: This paper proposes a method that consists in computing performance bounds to predict the average operational behavior of TPNs by exploiting their structural properties and by applying operational laws.
Abstract: Time Petri nets (TPNs) have been widely used for the verification and validation of real-time systems during the software development process. Their quantitative analysis consists in applying enumerative techniques that suffer the well known state space explosion problem. To overcome this problem, several methods have been proposed in the literature, that either provide rules to obtain equivalent nets with a reduced state space or avoid the construction of the whole state space. In this paper, we propose a method that consists in computing performance bounds to predict the average operational behavior of TPNs by exploiting their structural properties and by applying operational laws. Performance bound computation was first proposed for timed (Timed PNs) and stochastic Petri nets (SPNs). We generalize the results obtained for Timed PNs and SPNs to make the technique applicable to TPNs and their extended stochastic versions: TPN with firing frequency intervals (TPNFs) and extended TPNs (XTPNs). Finally, we apply the proposed bounding techniques on the case study of a robot-control application taken from the literature.

Journal ArticleDOI
TL;DR: The main limitations encountered when using a conventional reservation-based scheduler for serving non-real-time tasks are described and formally analyzed, and a novel algorithm that overcomes these problems is proposed (called HGRUB).
Abstract: Resource reservations are an effective technique to support hard and soft real-time applications in open systems. However, they generally focus on providing guarantees to real-time applications, without paying too much attention to the performance of non-real-time activities. In this paper, the main limitations encountered when using a conventional reservation-based scheduler for serving non-real-time tasks are described and formally analyzed. Then, a novel algorithm that overcomes these problems (called HGRUB) is proposed, and both theoretical and experimental evidence of its effectiveness is provided.

Journal ArticleDOI
TL;DR: This paper proposes and evaluates an extension to the Java's remote method invocation (RMI) with additional support for asynchronous remote invocations and discusses the set of changes it requires within their middleware programming interfaces and inside communication protocols to accommodate the proposed model.
Abstract: More and more, the use of real-time distribution middlewares programmed with high-level languages like Java is becoming of interest for industrial systems because this type of infrastructures reduce development efforts required to both design and maintain complex networked applications. In that way towards having better development tools, this paper deals with the very specific issue of the asynchronism from the particular perspective of Java's distributed technologies. It proposes and evaluates an extension to the Java's remote method invocation (RMI) with additional support for asynchronous remote invocations. Such a mechanism makes the transmission of some messages, typically those that do not require any confirmation from the server, much more efficient than synchronous communications, and consequently they optimize and speed up the performance of many industrial networked applications. In more detail, this paper concerns with the model itself and the set of changes it requires within their middleware programming interfaces and inside communication protocols to accommodate the proposed model. The proposal is supported by empirical evidences from a prototype developed as partial proof-of-concept.

Journal ArticleDOI
TL;DR: This paper presents a software tool that, given an accurate and machine-readable description of vulnerabilities, detects whether or not they are of concern and evaluates consequences in the context of a factory network.
Abstract: In modern factories, personal computers are starting to replace traditional programmable logic controllers, due to cost and flexibility reasons, and also because their operating systems now support programming environments even suitable for demanding real-time applications. These characteristics, as well as the ready availability of many software packages covering any kind of needs, have made the introduction of PC-based devices at the factory field level especially attractive. However, this approach has a profound influence on the extent of threats that a factory computing infrastructure shall be prepared to deal with. In fact, industrial personal computers share the same kinds of vulnerabilities with their office automation counterparts. Then, their introduction increases the risk of cyber-attacks. As the complexity of the network grows, the problem rapidly becomes hard to tackle by hand, due to the subtle and unforeseen interactions that may occur among apparently unrelated vulnerabilities, thus bearing the focus on the full automation of the analysis. Going into this direction, this paper presents a software tool that, given an accurate and machine-readable description of vulnerabilities, detects whether or not they are of concern and evaluates consequences in the context of a factory network.

Journal ArticleDOI
TL;DR: Time-drivenAccess and forwarding, a solution for guaranteeing deterministic delay, at both the access and forwarding level, in wireless multihop networks is described, its properties are analyzed, and its performance in industrial scenarios is assessed.
Abstract: The deployment of wireless technologies in industrial networks is very promising mainly due to their inherent flexibility. However, current wireless solutions lack the capability to provide the deterministic, low delay service required by many industrial applications. Moreover, the high level of interference generated by industrial equipment limits the coverage that ensures acceptable performance. Multihop solutions, when combining frame forwarding with higher node density, have the potential to provide the needed coverage while keeping radio communication range short. However, in multihop solutions, the medium access time at each of the nodes traversed additively contributes to the end-to-end delay and the forwarding delay (i.e., the time required for packets to be processed, switched, and queued) at each node is to be added as well. This paper describes time-driven access and forwarding, a solution for guaranteeing deterministic delay, at both the access and forwarding level, in wireless multihop networks, analyzes its properties, and assesses its performance in industrial scenarios.

Journal ArticleDOI
TL;DR: A neurofuzzy solution to process information deriving from an automatic optical system is proposed which provides a global quality index of a solder joint, starting from the assessment of a human inspector.
Abstract: Recently, surface mount technology is extensively used in the production of printed circuit boards due to the high level of miniaturization and to the increase of density in the electronic device integration. In such production process several defects could occur on the final electronic components, compromising its correct working. In this paper a neurofuzzy solution to process information deriving from an automatic optical system is proposed. The designed system provides a global quality index of a solder joint, starting from the assessment of a human inspector. This target is achieved by reproducing the modus operandi of the expert, evaluating the area, the shape and the barycentre position of a solder joint. The proposed architecture is constituted by three supervised neural networks and two fuzzy rule-based modules which automate expert's work and provide a refined evaluation of the quality. The considered solution presents some attractive advantages: a complex acquisition system is not needed, equipment costs could be reduced by shifting the assessment of a solder joint on the fuzzy parts. Moreover, intermediate variables used in the method could be employed as control parameters in the production process under analysis.