It has previously been shown that serially concatenated trellis coded modulation (SCTCM) with a non-recursive inner convolutional code can achieve convergence close to capacity. In this paper, we supplement the analys...
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It has previously been shown that serially concatenated trellis coded modulation (SCTCM) with a non-recursive inner convolutional code can achieve convergence close to capacity. In this paper, we supplement the analysis by comparing recursive and non-recursive inner codes with respect to the bit error rate (BER) of the error floor region. We show that the high error floor, commonly attributed to serially concatenated codes using a non-recursive inner code, can be reduced significantly through careful code design. The considered system is iteratively decoded SCTCM with an outer single parity check (SPC) code and a two-state rate 3/4 inner convolutional code whose output is mapped to 8PSK. Simulation results are shown for the additive white Gaussian noise (AWGN) channel.
作者:
Lankoski, PetriBjörk, StaffanMedia Lab.
University of Art and Design Helsinki Hämeentie 135 C FI-00560 Helsinki Finland Interaction Design Collegium
Computer Science and Engineering Chalmers University of Technology and Göteborg University SE-412 96 Göteborg Sweden
Descriptions of humans require several qualities for people to experience them as believable: human body;selfawareness, intentional states, and self impelled actions;expression of emotions;ability to use natural langu...
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Public spaces are changing from being ungoverned places for interaction to be more formalized, controlled, less interactive, and designed places aimed at fulfilling a purpose. Simultaneously, new personal mobile techn...
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ISBN:
(纸本)159593619X
Public spaces are changing from being ungoverned places for interaction to be more formalized, controlled, less interactive, and designed places aimed at fulfilling a purpose. Simultaneously, new personal mobile technology aims at providing private individual spaces in the public domain. In this paper we explore the implications of interacting in public space and how technology can be rethought to not only act as personal devices, but be the tool to reclaim the right and possibility to interact in public spaces. We introduce information exchange, social support and regulation as three central aspects for reclaiming public space. The PhotoSwapper application is presented as an example of a system designed to integrate pervasive technology in a public setting. The system is strongly inspired by the activities at a traditional market place. Based on the design of the application we discuss four design challenges when designing for public interaction. Copyright 2007 ACM.
As multi-core microprocessors are becoming widely adopted, the need to extract thread-level parallelism (TLP) from single-threaded applications in a seamless fashion increases. In this paper, we characterize the natur...
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As multi-core microprocessors are becoming widely adopted, the need to extract thread-level parallelism (TLP) from single-threaded applications in a seamless fashion increases. In this paper, we characterize the nature of TLP in embedded applications and study the limits of performance speedup using parallelizing compilers on platforms with and without support for thread-level speculation. First and somewhat expected, only two out of ten applications from the consumer and telecom domains of the EEMBC suite could be automatically parallelized on multi-core architectures without thread-level speculation (TLS) support. We systematically study the speedup obtained by parallelizing compiler technologies by factoring in the impact of the number of cores, thread decomposition strategies, and thread-management overhead. Overall, we have found that a TLS substrate is critical to uncover thread level parallelism and thread- management overhead must be low. On an eight-way multi-core system, it is possible to achieve a speedup of four, on average, for six out of the ten applications of EEMBC which we have analyzed.
This paper describes a process group membership protocol for distributed real-time systems, that use a communication network which supports both time-triggered (TT) and event-triggered (ET) communication. The protocol...
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This paper describes a process group membership protocol for distributed real-time systems, that use a communication network which supports both time-triggered (TT) and event-triggered (ET) communication. The protocol allows a group of cooperating real-time processes to establish a consistent view of each other's operational status, i.e. working correctly or not. The aim is to provide an application independent membership service in systems where several distributed real-time tasks share processing nodes. We assume that each such task consists of several processes executing on different nodes and that each node can execute processes belonging to different tasks. The protocol is applicable to any application domain, but has been developed for automotive active safety systems. Here, typical distributed real-time tasks include anti-lock braking, stability control and collision mitigation. In such systems, a membership service provides invaluable support for implementing fault-tolerance and graceful degradation.
We present a research program for identifying, modeling, and making use of generic pragmatic patterns for clinical knowledge management that support evidence-based medicine (EBM). Part of this program is SOMWeb, a sys...
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ISBN:
(纸本)9781595938596
We present a research program for identifying, modeling, and making use of generic pragmatic patterns for clinical knowledge management that support evidence-based medicine (EBM). Part of this program is SOMWeb, a system based on Semantic Web technologies, which is used for knowledge sharing and dissemination within an oral medicine community. A study of the use of SOMWeb has been conducted as the first step in the elicitation of important contextual factors and communicative activities involved in knowledge sharing processes in oral medicine. One such activity, community discussion activation, is described using consultation patterns together with the collaboration patterns of [5]. The general need for context-aware health information systems and the prospective use of approaches within Pragmatic Web in the pursuit of EBM are also discussed. Copyright 2007 ACM.
The decidability of equality is proved for Martin-Löf type theory with a universe á la Russell and typed beta-eta- equality judgements. A corollary of this result is that the constructor for dependent functi...
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The decidability of equality is proved for Martin-Löf type theory with a universe á la Russell and typed beta-eta- equality judgements. A corollary of this result is that the constructor for dependent function types is injective, a property which is crucial for establishing the correctness of the type-checking algorithm. The decision procedure uses normalization by evaluation, an algorithm which first interprets terms in a domain with untyped semantic elements and then extracts normal forms. The correctness of this algorithm is established using a PER-model and a logical relation between syntax and semantics.
Moore's law has deliver tera-scale level transistor integration capacity. Power, variability, reliability, aging, and testing are pose as barriers and challenges to harness this integration capacity. Advances in m...
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ISBN:
(纸本)3981080122
Moore's law has deliver tera-scale level transistor integration capacity. Power, variability, reliability, aging, and testing are pose as barriers and challenges to harness this integration capacity. Advances in microarchitecture and programming systems discussed in this paper are potential solutions
The use of Radio Frequency Identification systems (RFID) is growing rapidly. Today, mostly "passive" RFID systems are used because no onboard energy source is needed on the transponders. However, "activ...
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The use of Radio Frequency Identification systems (RFID) is growing rapidly. Today, mostly "passive" RFID systems are used because no onboard energy source is needed on the transponders. However, "active" RFID technology, with onboard power sources in the transponders, gives a range of opportunities not possible with passive systems. To obtain energy efficiency in an Active RFID system the protocol to be used should be carefully designed with energy optimization in mind. This paper describes how energy consumption can be calculated, to be used in protocol definition, and how evaluation of protocol in this respect can be made. The performance of such a new protocol, in terms of energy efficiency, aggregated throughput, delay, and number of air collisions is evaluated and compared to an existing, commercially available protocol for Active RFID, as well as to the IEEE standard 802.15.4 (used e.g. in the Zigbee medium-access layer).
In this paper we will show how to obtain a better comprehension of the behavior of large and complex software systems using visualization and program animation. Use cases are used in the software development industry ...
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In this paper we will show how to obtain a better comprehension of the behavior of large and complex software systems using visualization and program animation. Use cases are used in the software development industry for the purpose of better understanding of software systems. The problem is that use cases for large and complex software systems are themselves large and complex. We have built a tool called Scenario Explorer to help the user handle this complexity by guiding him or her through the use cases. The user is provided with just enough information to comprehend the behavior of interest. Tools like this are crucial for developers that need to obtain a better comprehension of a whole software system, for example newcomers in a project or managers. ScenarioExplorer was built at Ericsson and applied to a subset of a large and complex software system.
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