Property:Abstract
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| 2011 Baltic Congress on Future Internet and Communications (BCFIC Riga 2011) + | <p>BCFIC Riga 2011 will address all the challenges of building the Future Internet, which will be based on mobile, wireless and fixed broadband communications infrastructures. It will become a stage for researchers, officials, decision makers, practitioners from the public sector and industry.</p> |
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| 3GPP LTE Versus IEEE 802.11p/WAVE : Which Technology is Able to Support Cooperative Vehicular Safety Applications? + | <p>The concept of vehicular ad-hoc networks enables the design of emergent automotive safety applications, which are based on the awareness among vehicles. Recently, a suite of 802.11p/WAVE protocols aimed at supporting car-to-car communications was approved by IEEE. Existing cellular infrastructure and, above all 3GPP LTE, is being considered as another communication technology appropriate for vehicular applications. This letter provides a theoretical framework which compares the basic patterns of both the technologies in the context of safety-of-life vehicular scenarios. We present mathematical models for the evaluation of the considered protocols in terms of successful beacon delivery probability.</p> |
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| A Centralized Channel Assignment Algorithm for Clustered Ad Hoc Networks + | <p>This paper presents new channel assignment algorithm for a clustered ad hoc network. The suggested method is based on a graph-theoretic model and seeks a solution for the channel assignment problem in a clustered ad hoc network. The method is based on a new meta-heuristic algorithm that is referred to as imperialist competitive algorithm (ICA). It provides a scheme for allocating the available channels to the cluster heads, maximizing spectrum efficiency and minimizing co-channel interference.<strong> </strong>The suggested method is tested for several scenarios and its performance is compared with a genetic algorithm based scheme. © 2013 IEEE</p> |
| A Communication Library for Mapping Dataflow Applications on Manycore Architectures + | <p>Dataflow programming is a promising paradigm for high performance embedded parallel computing. When mapping a dataflow program onto a manycore architecture a key component is the library to express the communication between the actors. In this paper we present a dataflow communication library supporting the CAL actor language. A first implementation of the communication library is created for Adapteva’s manycore architecture Epiphany that contains an onchip 2-D mesh network. Three different buffering methods, with and without direct memory access (DMA) transfer, have been implemented and evaluated. We have also made a preliminary study on the effect of mapping strategies of the actors onto the cores. The assessment of the library is based on a CAL implementation of a two dimensional inverse discrete cosine transform (2D-IDCT) and our own CAL-to-C compilation framework. As expected the results show that the most efficient actor to-core mapping strategy is to keep the communication to the nearest neighbor communication pattern as much as possible. Thus, the best way to place a pipelined sequence of computations like our 2D-IDCT is to place the actors into cores in a serpentine fashion. For this application we found that the simple receiver side buffer outperforms the more complicated buffering strategies that used DMA transfer.</p> |
| A Communication Library for Mapping Dataflow Applicationson Manycore Architectures + | <p>Dataflow programming is a promising paradigm for high performance embedded parallel computing. When mapping a dataflow program onto a manycore architecture a key component is the library to express the communication between the actors. In this paper we present a dataflow communication library supporting the CAL actor language. A first implementation of the communication library is created for Adapteva’s manycore architecture Epiphany that contains an onchip 2-D mesh network. Three different buffering methods, with and without direct memory access (DMA) transfer, have been implemented and evaluated. We have also made a preliminary study on the effect of mapping strategies of the actors onto the cores. The assessment of the library is based on a CAL implementation of a two dimensional inverse discrete cosine transform (2D-IDCT) and our own CAL-to-C compilation framework. As expected the results show that the most efficient actor to-core mapping strategy is to keep the communication to the nearest neighbor communication pattern as much as possible. Thus, the best way to place a pipelined sequence of computations like our 2D-IDCT is to place the actors into cores in a serpentine fashion. For this application we found that the simple receiver side buffer outperforms the more complicated buffering strategies that used DMA transfer.</p> |
| A Compositional Implementation of Modbus in Protege + | <p>Network protocols today play a major role in embedded software for industrial automation, with constant efforts to adapt existing device software to new emerging standards. In earlier work, we have proposed a compilation-based approach using a domain-specific language, Protege, which automatically generates protocol stack implementations in C from modular high-level descriptions. In this paper, we provide a case study of the Protege language in an industrial setting. We have implemented the Modbus protocol over TCP/IP and over serial line, and tested it using an industrial gateway. Our implementation demonstrates Protege's advantages for software productivity, easy maintenance and code reuse, and it achieves many desirable properties of industrial embedded network software.</p> |
| A Congruence Rule Format with Universal Quantification + | <p>We investigate the addition of universal quantification to the meta-theory of Structural Operational Semantics (SOS). We study the syntax and semantics of SOS rules extended with universal quantification and propose a congruence rule format for strong bisimilarity that supports this new feature. © 2007 Elsevier B.V. All rights reserved.</p> |
| A Core Language for Executable Models of Cyber Physical Systems : work in progress report + | <p>Recently we showed that an expressive class of mathemat-ical equations can be automatically translated into simula-tion codes. Focusing on the expressivity of equations oncontinuous functions, this work considered only minimal in-teraction with discrete behaviors and only a static numberof statically connected components. However, the interac-tion between continuous and hybrid components in manycyber physical domains is highly coupled, and such systemsare often highly dynamic in both respects. This paper givesan overview of a proposed core language for capturing ex-ecutable hybrid models of highly dynamic cyber physicalsystems.</p> |
| A Core Language for Executable Models of Cyber-Physical Systems (Preliminary Report) + | <p>Recently we showed that an expressive class of mathematical equations can be automatically translated into simulation codes. By focusing on the expressivity of equations formed from continuous functions, this work did not accommodate a wide range of discrete behaviors or a dynamic collection of components. However, the interaction between continuous and hybrid components in many cyber-physical domains is highly coupled, and such systems are often highly dynamic in both respects. This paper gives an overview of a proposed core language for capturing executable hybrid models of highly dynamic cyber-physical systems. © 2012 IEEE.</p> |
| A Database-Centric Architecture for Home-Based Health Monitoring + | <p>Traditionally, database management systems (DBMSs) have been employed exclusively for data management in infrastructures supporting Ambient Assisted Living (AAL) systems. However, DBMSs provide other mechanisms, such as for security, dependability, and extensibility that can facilitate the development, use, and maintenance of AAL applications. This work utilizes such mechanisms, particularly extensibility, and proposes a database-centric architecture to support home-based healthcare applications. An active database is used to monitor and respond to events taking place in the home, such as bed-exits. In-database data mining methods are applied to model early night behaviors of people living alone. Encapsulating the processing into the DBMS avoids transferring and processing sensitive data outside of database, enables changes in the logic to be managed on-the-fly, and reduces code duplication. As a result, such an approach leads to better performance and increased security and privacy, and can facilitate the adaptability and scalability of AAL systems. An evaluation of the architecture with datasets collected in real homes demonstrated the feasibility and flexibility of the approach.</p> |
| A Design Methodology for Resource to Performance Tradeoff Adjustment in FPGAs + | <p>When implementing computation-intensive algorithms on finegrained parallel architectures, adjustment of resource to performance tradeoff is a big challenge. This paper proposes a methodology for dealing with some of these performance tradeoffs by adjusting parallelism at different levels. In a case study, interpolation kernels are implemented on a fine-grained architecture (FPGA) using a high level language (Mitrion-C). For both cubic and bi-cubic interpolation, one single-kernel, one cross-kernel and two multi-kernel parallel implementations are designed and evaluated. Our results demonstrate that no single level of parallelism can be used for trade-off adjustment. Instead, the appropriate degree of parallelism on each level, according to available resources and the performance requirements of the application, needs to be found. Basing the design on high-level programming simplifies the trade-off process. This research is a step towards automation of the choice of parallelization based on a combination of parallelism levels.</p> |
| A Domain Specific Approach to Network Software Architecture : Assuring Conformance Between Architecture and Code + | <p>Network software is typically organized according toa layered architecture that is well understood. However, writingcorrect and efficient code that conforms with the architecture stillremains a problem. To overcome this problem we propose to usea domain specific language based approach. The architecturalconstraints are captured in a domain specific notation that can beused as a source for automatic program generation. Conformancewith the architecture is thus assured by construction. Knowledgefrom the domain allows us to generate efficient code. In addition,this approach enforces reuse of both code and designs, one ofthe major concerns in software architecture. In this paper, weillustrate our approach with PADDLE, a tool that generates packetprocessing code from packet descriptions. To describe packets weuse a domain specific language of dependent types that includespacket overlays. From the description we generate C librariesfor packet processing that are easy to integrate with other partsof the code. We include an evaluation of our tool.</p> |
| A Domain-Specific Language Approach to Protocol Stack Implementation + | <p>This paper describes a domain-specific language embeddedin Haskell, IPS, for the implementation of protocol stacks for embeddedsystems. IPS profits from Haskell’s features and generates C implementationsby embedded compilation.</p> |
| A Domain-specific Approach for Software Development on Manycore Platforms + | <p>The programming complexity of increasingly parallel processors calls for new tools that assist programmers in utilising the parallel hardware resources. In this paper we present a set of models that we have developed as part of a tool for mapping dataflow graphs onto manycores. One of the models captures the essentials of manycores identified as suitable for signal processing, and which we use as target for our algorithms. As an intermediate representation we introduce timed configuration graphs, which describe the mapping of a model of an application onto a machine model. Moreover, we show how a timed configuration graph by very simple means can be evaluated using an abstract interpretation to obtain performance feedback. This information can be used by our tool and by the programmer in order to discover improved mappings.</p> |
| A Ethernet based Metropolitan Area Open Access Architecture + | <p>Quality of Service (QoS) has become increasingly important in metropolitan area networks and even more important in open access networks where service providers should be able to offer their services on equal terms. This paper present a network architecture with a hierarchical star-mesh topology, which provides the scalability and redundancy required for future open access networks. To support QoS a combination of Ethernet and Multiprotocol Label Switching (MPLS) is proposed. With the use of a switch, on the highest level, based on micro electromechanical system (MEMS) technology this proposed architecture could reach aggregated bitrates above 10 Tbit/s. IPSec is proposed for solving the security issues in the network that emerges when different service providers share the same network and future applications are developed.</p> |
| A Fibre-Optic AWG-Based Real-Time Network and Its Applicability to High-Performance Embedded Computing + | <p>In this paper, an architecture and a Medium Access Control (MAC) protocol for a multi-wavelength optical communication network, applicable in short range communication systems like System Area Networks (SANs), are proposed. The main focus lies on guaranteed support for hard and soft real-time traffic. The network is based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its center. Traffic scheduling is centralized in one node (residing together with the AWG in a hub), which communicates through a physical control channel. The AWG's property of spatial wavelength reuse and the combination of fixed-tuned and tunable transceivers in the nodes enable simultaneous control and data transmission. A case study with defined real-time communication requirements in the field of Radar Signal Processing (RSP) was carried out and indicates that the proposed system is very suitable for this kind of application.</p> |
| A First Course on Cyber Physical Systems + | <p>Effective and creative CPS development requires expertise in disparate fields that have traditionally been taught in distinct disciplines. At the same time, students seeking a CPS education generally come from diverse educational backgrounds. In this paper we report on our recent experience developing and teaching a course on CPS. The course can be seen as a detailed proposal focused on three three key questions: What are the core elements of CPS? How can these core concepts be integrated in the CPS design process? What types of modeling tools can assist in the design of cyber-physical systems? Experience from the first two offerings of the course is promising, and we discuss the lessons learned. All materials including lecture notes and software used for the course are openly available online.</p> |
| A Gentle Introduction to Multi-stage Programming, Part II + | <p>As domain-specific languages (DSLs) permeate into mainstream software engineering, there is a need for economic methods for implementing languages. Following up on a paper with a similar title, this paper focuses on dynamically typed languages, covering issues ranging from parsing to defining and staging an interpreter for an interesting subset of Dr. Scheme. Preliminary experimental results indicate that the speedups reported in previous work for smaller languages and with smaller benchmarks are maintained. © 2008 Springer Berlin Heidelberg.</p> |
| A Library for Processing Ad hoc Data in Haskell : Embedding a Data Description Language + | <p>Ad hoc data formats, i.e. semistructured non-standard dataformats, are pervasive in many domains that need software tools—bioinformatics,demographic surveys, geophysics and network software are justa few. Building tools becomes easier if parsing and other standard inputoutputprocessing can be automated. Modern approaches for dealingwith ad hoc data formats consist of domain specific languages based ontype systems. Compilers for these languages generate data structures andparsing functions in a target programming language in which tools andapplications are then written. We present a monadic library in Haskellthat implements a data description language. Using our library, Haskellprogrammers have access to data description primitives that can be usedfor parsing and that can be integrated with other libraries and applicationprograms without the need of yet another compiler.</p> |
| A Methodology for Generating Verified Combinatorial Circuits + | <p>High-level programming languages offer significant expressivitybut provide little or no guarantees about resource use. Resourcebounded languages — such as hardware-description languages —provide strong guarantees about the runtime behavior of computations but often lack mechanisms that allow programmers to writemore structured, modular, and reusable programs. To overcomethis basic tension in language design, recent work advocated the useof Resource-aware Programming (RAP) languages, which take intoaccount the natural distinction between the development platformand the deployment platform for resource-constrained software.This paper investigates the use of RAP languages for the generation of combinatorial circuits. The key challenge that we encounteris that the RAP approach does not safely admit a mechanism to express a posteriori (post-generation) optimizations. The paper proposes and studies the use of abstract interpretation to overcome thisproblem. The approach is illustrated using an in-depth analysis ofthe Fast Fourier Transform (FFT). The generated computations arecomparable to those generated by FFTW.</p> |
| A Monadic Approach for Avoiding Code Duplication when Staging Memoized Functions + | <p>Building program generators that do not duplicate generated code can be challenging. At the same time, code duplication can easily increase both generation time and runtime of generated programs by an exponential factor. We identify an instance of this problem that can arise when memoized functions are staged. Without addressing this problem, it would be impossible to effectively stage dynamic programming algorithms. Intuitively, direct staging undoesthe effect of memoization. To solve this problem once and for all, and for any function that uses memoization, we propose a staged monadic combinator library. Experimental results confirm that the library works as expected. Preliminary results also indicate that the library is useful even when memoization is not used.</p> |
| A New Approach to Data Mining for Software Design + | <p>We propose Exact Software Design Mining (ESDM)as a new approach to managing large software systems. ESDM is concerned with automatically extracting a program generator capable of exactly reconstructing the full code base. To illustrate thepotential effectiveness of this approach, we propose,implement, and test a basic algorithm extractingsuch generators. Experimental results on variousbenchmarks (including the Linux kernel) are encouraging.</p> |
| A New Two-Degree-of-Freedom Space Heating Model for Demand Response + | <p>In today’s fast changing electric utilities sector demand response (DR) programs are a relatively inexpensive means of reducing peak demand and providing ancillary services. Advancements in embedded systems and communication technologies are paving the way for more complex DR programs based on transactive control. Such complex systems highlight the importance of modeling and simulation tools for studying and evaluatingthe effects of different control strategies for DR. Considerable efforts have been directed at modeling thermostatically controlled appliances. These models however operate with only one degree of freedom, typically, the thermal mass temperature. This paper proposes a two-degree-of-freedom residential space heating systemcomposed of a thermal storage unit and forced convection system. Simulation results demonstrate that such system is better suited for maintaining thermal comfort and allows greater flexibility for DR programs. The performance of several control strategies are evaluated, as well as the effects of model and weather parameterson thermal comfort and power consumption.</p> |
| A Pipelined Ring Network - Heterogeneous Real-time in Radar Signal Processing + | <p>The paper presents results of simulations done with the CCR-EDF (Control Channel based Ring network with EDF scheduling) pipelined ring network together with a case study of system area networks for radar signal processing. The topology of the network is a pipelined unidirectional fibre-ribbon ring that supports several simultaneous transmissions in non-overlapping segments. Access to the network is divided into slots. In each slot the node that has the highest priority message is permitted to transmit. This feature of the medium access protocol gives the network the functionality for earliest deadline first scheduling. Different classes of traffic are supported for the user. These are guaranteed logical real-time channels (LRTC), best effort (BE) channels and non real-time (NRT) traffic. The case study used is from an airborne radar signal processing (RSP) application. Results of the simulations indicate that the CCR-EDF network works well with the RSP application studied.</p> |
| A Semantic Analysis of C++ Templates + | <p>Templates are a powerful but poorly understood feature ofthe C++ language. Their syntax resembles the parameterized classes ofother languages (e.g., of Java). But because C++ supports template specialization, their semantics is quite different from that of parameterizedclasses. Template specialization provides a Turing-complete sub-languagewithin C++ that executes at compile-time. Programmers put this powerto many uses. For example, templates are a popular tool for writingprogram generators.The C++ Standard defines the semantics of templates using natural language, so it is prone to misinterpretation. The meta-theoretic propertiesof C++ templates have not been studied, so the semantics of templateshas not been systematically checked for errors. In this paper we presentthe first formal account of C++ templates including some of the morecomplex aspects, such as template partial specialization. We validate oursemantics by proving type safety and verify the proof with the Isabelleproof assistant. Our formalization reveals two interesting issues in theC++ Standard: the first is a problem with member instantiation and thesecond concerns the generation of unnecessary template specializations.</p> |
