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Object/Component/Service-Oriented Real-Time Distributed Computing (ISORC), 2011 14th IEEE International Symposium on

Date 28-31 March 2011

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Displaying Results 1 - 25 of 44
  • [Front cover]

    Page(s): C1
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  • [Title page i]

    Page(s): i
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  • [Title page iii]

    Page(s): iii
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  • [Copyright notice]

    Page(s): iv
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  • Table of contents

    Page(s): v - viii
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  • Message from the Symposium Co-chairs

    Page(s): ix
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  • Message from the Program Co-chairs

    Page(s): x
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  • Organization Committee

    Page(s): xi
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  • International Program Committees

    Page(s): xii - xiii
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  • Secondary Reviewers

    Page(s): xiv
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  • Maximizing Service Uptime of Smartphone-Based Distributed Real-Time and Embedded Systems

    Page(s): 3 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB) |  | HTML iconHTML  

    Smart phones are starting to find use in mission critical applications, such as search-and-rescue operations, wherein the mission capabilities are realized by deploying a collaborating set of services across a group of smart phones involved in the mission. Since these missions are deployed in environments where replenishing resources, such as smart phone batteries, is hard, it is necessary to maximize the lifespan of the mission while also maintaining its real-time quality of service (QoS) requirements. To address these requirements, this paper presents a deployment framework called Smart Deploy, which integrates bin packing heuristics with evolutionary algorithms to produce near-optimal deployment solutions that are computationally inexpensive to compute for maximizing the lifespan of smart phone-based mission critical applications. The paper evaluates the merits of deployments produced by Smart Deploy for a search-and-rescue mission comprising a heterogeneous mix of smart phones by integrating a worst-fit bin packing heuristic with particle swarm optimization and genetic algorithm. Results of our experiments indicate that the missions deployed using Smart Deploy have a lifespan that is 20% to 162% greater than those deployed using just the bin packing heuristic or evolutionary algorithms. Although Smart Deploy is slightly slower than the other algorithms, the slower speed is acceptable for offline computations of deployment. View full abstract»

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  • Dynamic Quality of Service Management for Multicast Tactical Communications

    Page(s): 11 - 18
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    Wireless networking is moving toward the adoption of IP protocols and away from the multitude of special-purpose tactical radios traditionally in the hands of emergency personnel, military personnel, and law enforcement. The adoption of standards, such as IP multicast, has facilitated this. IP multicast also enables recovering some of the advantages of the broadcast medium when using IP in tactical environments. However, the traditional Quality of Service (QoS) approaches for IP multicast fall short of satisfying the stringent QoS requirements in tactical environments, which typically have single-hop, line-of-sight connections. The reasons for this are (1) QoS in IP networks, frequently based on Differentiated Services, relies on routers to enforce the priorities which typically don't exist in tactical networks, and (2) QoS for tactical users needs to be enforced at the information level, not the packet level where the loss or delay of a single packet can invalidate an entire object of information. We present strategies for QoS management for IP multicast in tactical environments that provides information and user-level QoS and addresses the specific challenges of tactical radios (such as the lack of reliable capacity information). We present our solutions in the context of a tactical information broker that provides beyond line-of-sight information management in a theater of operations. View full abstract»

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  • A Selection Method for Services in Dynamic Environments

    Page(s): 19 - 23
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    Service selection is one of the current challenges in Service Oriented Computing (SOC). We propose a service selection method for replacing used services in case of a failure. The approach considers the functional as well as the non-functional features of services. Furthermore, the service selection method searches for a service just meeting the requirements and not for the best possible service exceeding the requirements. This saves services having high QoS properties for clients really in need of them. View full abstract»

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  • Predictable Communication for Mobile Systems

    Page(s): 24 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    Many industrial and medical scenarios today are building on mobile devices as their end systems. These devices are typically connected to backend systems via the mobile phone network with their corresponding data services. Today's network protocols are optimized for reliable transfer of voice traffic, however, available bandwidth and latency for data traffic may vary significantly with location and motion speed of a mobile device. Within this paper, we report on experiences from our eHealth project "Fontane", where real-time streaming data from electrocardiographic devices has to be transferred from patient's home to doctors at a telemedicine center. In order to deal with varying bandwidth and transmission characteristics on the radio link, we propose a predictive model that allows for pro-active application reconfiguration in order to adapt to anticipated bandwidth variations. Our model is being integrated into a self-adaptive middleware for mobile communication. We present our initial study on network bandwidth estimation, which reveals that the measurement of the available bandwidth using standard end-to-end methods does not work well for mobile cellular networks due to a fairly high number of interference factors in wireless environments. We therefore propose a multilevel forecast model to better predict the network bandwidth of the immediate future. View full abstract»

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  • Authentication in Time-Triggered Systems Using Time-Delayed Release of Keys

    Page(s): 31 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (405 KB) |  | HTML iconHTML  

    This paper investigates on the security of time -- triggered transmission channels, which are used to establish a predictable and timely message transfer in a distributed embedded system with potential safety constraints. Within such a system, safety and security are closely related, because malicious attacks can have an impact on a system's safety and thereby cause severe damage. An attacker could masquerade as an original sender and try to alter some system parameters by injecting malicious messages in the system. In the embedded real-time systems domain particularly the authenticity of data items is of interest, because a lack of integrity can lead to incorrect or erroneous system behavior. In addition, we address the open research question how a common notion of time can contribute to a system's security. Our solution encompasses an authentication protocol to secure time-triggered transmission channels. We illustrate two attack scenarios (insertion and substitution) that aim at injecting fake messages in such a channel thereby corrupting the internal system state of a receiver. We discuss the feasibility of several key management strategies for embedded systems and describe an authentication protocol using time-delayed release of symmetric keys for time-triggered systems. In a case study we implement the protocol for a prototype Time-Triggered Ethernet (TTE) system. The insight gained from the evaluation is that the computation of the cryptographic algorithms consumes most resources. Our solution shows that authentication can be transparently applied to a time-triggered system exploiting the available global time base and without violating its timeliness properties. View full abstract»

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  • Real-Time Multicast and Memory Replication Channels with Delay Bounded Error Detection and Retry Capabilities

    Page(s): 40 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (557 KB) |  | HTML iconHTML  

    In order to accommodate different requirements of reliable multicast applications, the real-time reliable multicasting support framework must possess generic yet rich features for detecting and reporting message losses with tight latency bounds. One highly promising concrete formulation of a multicast framework is the Real-time Multicast & Memory Replication Channel (RMMC) scheme. In this paper, we present the Delay-Bounded Reliable RMMC (DBR-RMMC) scheme, which extends the RMMC scheme in order to yield tight bounds on the latencies in detecting and reporting message losses over RMMCs and to enable application layer to initiate timely recovery actions. The DBR-RMMC scheme offers an API that allows application developers to freely explore the various design dimensions of reliable multicast applications while assuring timeliness. We also discuss a middleware subsystem devised to support DBRRMMC, followed by a summary of several analytical results on the bounds for latencies in reacting to the occurrence of a message loss. Experiments involving a real-time video streaming application have been conducted and encouraging results are presented. View full abstract»

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  • Scheduling Multi Clock Real Time Systems: From Requirements to Implementation

    Page(s): 50 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (441 KB) |  | HTML iconHTML  

    This paper presents an approach for modeling simulating and analyzing multi clocks real time systems during the different steps of a design. These steps range from the first requirements to a model allocated on a specific execution platform. The UML MARTE profile and the CCSL language are used together to specify the causal and temporal characteristics of the software as well as the hardware parts of the system. The TimeSquare environment allows a simulation of such specification and the detection of potential errors and deadlocks. When the specification refinement is finished, to prove the specification correctness, the CCSL specification is used to generate a synchronous model and some observers in Esterel. We illustrate the approach through a spark ignition control system. View full abstract»

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  • Modeling MARTE Sequence Diagram with Timing Pi-Calculus

    Page(s): 61 - 66
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    Modeling and Analysis of Real-Time and Embedded Systems specification (MARTE) is a profile of the Unified Modeling Language (UML) for model driven development of real-time and embedded systems. To describe formally the semantics of MARTE sequence diagram (MARTE SD), we introduce the timing pi-calculus, a new variant of the pi-calculus, in this paper. The good feature of the timing pi-calculus is that it can handle time elapse and timer events. We provide both its syntax and semantics. With the new calculus, we then model MARTE SD elements, and give their precise semantics. Our formal framework may facilitate the reliability and consistency analysis of MARTE SD design process. View full abstract»

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  • A Model-Based Transformation Process to Validate and Implement High-Integrity Systems

    Page(s): 67 - 74
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (831 KB) |  | HTML iconHTML  

    Despite numerous advances, building High-Integrity Embedded systems remains a complex task. They come with strong requirements to ensure safety, schedulability or security properties, one needs to combine multiple analysis to validate each of them. Model-Based Engineering is an accepted solution to address such complexity: analytical models are derived from an abstraction of the system to be built. Yet, ensuring that all abstractions are semantically consistent, remains an issue, e.g. when performing model checking for assessing safety, and then for schedulability using timed automata, and then when generating code. Complexity stems from the high-level view of the model compared to the low-level mechanisms used. In this paper, we present our approach based on AADL and its behavioral annex to refine iteratively an architecture description. Both application and runtime components are transformed into basic AADL constructs which have a strict counterpart in classical programming languages or patterns for verification. We detail the benefits of this process to enhance analysis and code generation. This work has been integrated to the AADL-tool support OSATE2. View full abstract»

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  • Modeling Interface Definition Language Extensions (IDL3+) Using Domain-Specific Modeling Languages

    Page(s): 75 - 82
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    Model-driven engineering (MDE) of distributed real-time and embedded (DRE) systems built using distributed middleware technologies typically rely on interface definition language (IDL) to define interfaces and attributes of the system under development. Recent needs for using IDL to design and implement systems composed of heterogeneous communication architectures, however, has realized the limitations of IDL. To address these limitations, vendors have proposed several non-trivial extensions to IDL also known as IDL3+. In order to leverage such extensions in the modeling domain, it is necessary to update existing tools, e.g., domain-specific modeling languages) to support such extensions. This paper provides two contributions to MDE of DRE systems using domain-specific modeling languages (DSMLs). First, this paper highlights the technical challenges associated with modeling IDL3+. Secondly, this paper discusses how to overcome such challenges in the context of a representative DSML for modeling DRE systems designed and implemented using IDL3+. Experience gained from using DSMLs to model IDL3+ shows that DSML environments as is do not suffice and need improved application frameworks to support complex DSMLs, such as IDL3+. View full abstract»

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  • A Generalized Model to Control the Throughput in a Processor for Real-Time Applications

    Page(s): 83 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (322 KB) |  | HTML iconHTML  

    In this paper we present a control theory approach to stabilize the throughput of threads for real-time applications on a multithreaded processor. We use a statistical model of a super scalar, multi-threaded processor as transfer function to calculate the resulting IPC rate. Our control theory approach is not limited to a specific processor and can be adapted to different microprocessor architectures. We are able to guarantee a minimum IPC rate within a defined convergence interval. Furthermore our results provide a method to improve WCET analysis, because inaccuracies of the processor model are soften by the use of our control theory approach. View full abstract»

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  • Modeling and Analyzing Real-Time Data Streams

    Page(s): 91 - 98
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1442 KB) |  | HTML iconHTML  

    Achieving situation awareness is especially challenging for real-time data stream applications because they i) operate on continuous unbounded streams of data, and ii) have inherent real-time requirements. In this paper we show how formal data stream modeling and analysis can be used to better understand stream behavior, evaluate query costs, and improve application performance. We use MEDAL, a formal specification language based on Petri nets, to model the data stream queries and the Quality-of-Service (QoS) management mechanisms in a data stream system. MEDAL's ability to combine query logic and data admission control in one model allows us to design a single comprehensive model of the system. This model can be used to perform a large set of analyses to help improve the application's performance and QoS. View full abstract»

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  • A Time-Predictable Object Cache

    Page(s): 99 - 105
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    Static cache analysis for data allocated on the heap is practically impossible for standard data caches. We propose a distinct object cache for heap allocated data. The cache is highly associative to track symbolic object addresses in the static analysis. Cache lines are organized to hold single objects and individual fields are loaded on a miss. This cache organization is statically analyzable and improves the performance. In this paper we present the design and implementation of the object cache in a uniprocessor and chip-multiprocessor version of the Java processor JOP. View full abstract»

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  • Refactoring Real-Time Java Profiles

    Page(s): 109 - 116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (707 KB) |  | HTML iconHTML  

    Just like other software, Java profiles benefits from refactoring when they have been used and have evolved for some time. This paper presents a refactoring of the Real-Time Specification for Java (RTSJ) and the Safety Critical Java (SCJ) profile (JSR-302). It highlights core concepts and makes it a suitable foundation for the proposed levels of SCJ. The ongoing work of specifying the SCJ profile builds on sub classing of RTSJ. This spurred our interest in a refactoring approach. It starts by extracting the common kernel of the specifications in a core package, which defines interfaces only. It is then possible to refactor SCJ with its three levels and RTSJ in such a way that each profile is in a separate package. This refactoring results in cleaner class hierarchies with no superfluous methods, well defined SCJ levels, elimination of SCJ annotations like @SCJAllowed, thus making the profiles easier to comprehend and use for application developers and students. View full abstract»

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  • The Design of Middleware Support for Real-Time SOA

    Page(s): 117 - 124
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    Service-oriented architectures (SOA) provide application systems the flexibility and cost-savings of dynamically composing workflows from reusable services. However, current SOA frameworks do not provide support for real-time workflow planning and execution. The goal of the RT-Llama SOA middleware framework is to address these new requirements. It works both at the service-level, by enhancing existing SOA middleware with service execution reservation capabilities, and at the end-to-end workflow-level, by creating a distributed component infrastructure for deadline-based workflow composition. This paper focuses on the design and implementation of the Virtual CPU (VCPU) resource scheduling scheme in RT-Llama to achieve predictable process executions. We have created a prototype implementation of RT-Llama using Sun Real-time JVM running on Solaris OS. Experiments consisting of real world service applications show that requests with end-to-end deadlines can be admitted and completed before deadlines with the VCPU scheme. We also show that service class differentiation can be achieved. View full abstract»

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