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Background: News media play a critical role in communicating risks and shaping public perceptions of social issues. Covering a multilayered disaster that grew from a local story to a national one, the ways that news media at different levels construct the Flint water crisis have not been previously explored. Literature review: Despite the well-established role of journalism as a government watchdog, news media do not neutrally mirror every social event. Instead, news reporting, highly mediated by language, is filled with political interests, values, and attitudes. Research questions: 1. How did local/regional and national newspapers construct the Flint water crisis? 2. Are there any similarities and/or differences in local/regional and national news construction of the Flint water crisis? 3. What are the practical implications for media coverage of risks, emergencies, or crises? 4. What are the methodological implications of this study for professional communication research? Methodology: This study integrates corpus linguistics and critical discourse analysis to analyze 1858 news reports about the Flint water crisis published between 2014 and 2018. I use keywords as a core analytical technique to compare the local/regional and national news coverage. Results: The results show that both local and national news reports overemphasized government activities while downplaying the unofficial voices of Flint residents and community activists. In addition, national newspapers were more likely than local newspapers to use racial cues in describing the Flint community and to associate the crisis with other social problems. Conclusions: This study suggests that news media should provide wide coverage of the affected community's efforts in risk/crisis communication rather than reproducing official messages. News representations should be cautious of strengthening stereotypes or forming negative conceptual associations of traditionally disenfranchised communities. [ABSTRACT FROM AUTHOR]

This paper presents techniques that are expected to improve the bit error rate (BER) performance of Unmanned Aerial Vehicles (UAVs) communication systems. The decode-and-forward (DF)-based cooperative multi-hop Rician network using space shift keying (SSK) modulation is employed for this purpose. The SSK modulation and cooperative communication are merged and used together. This enhances the BER performance for multiple-input multiple-output (MIMO) channels, thus accentuating its significance as an important technique for consistently reliable communication methodology while, at the same time, eliminating wastage of energy. The new technique is named as high performance (HP) due to not only BER performance improvement but also increase of the diversity of the communication system. This new model is further used for multi-hop networks and the resulting BER characteristics are assessed for possible enhanced performance in Rician channels. The paper also showcases the generalized-n-hop BER equation for various multi-hop DF-based cooperative communication systems in diverse UAV models. The Monte Carlo simulations further confirm the theoretical results that already exist for transmit-receive antennas. This work also underlines the fact that the number of hops in a communication system has no bearing whatsoever on the BER performance diversity value. [ABSTRACT FROM AUTHOR]

Background: Engineers increasingly work and advance their careers in international business settings. As technical managers, they need management and technical skills when working with different stakeholders with whom they may not share a common first language. Studies have revealed that informal oral communication skills are of prime importance for global engineers who face challenges in building shared meaning and formulating clear messages in meetings with non-native speakers of English. This article proposes that studying the use of multimodal resources (spoken language, gaze, gestures, and objects) in meetings can unpack how work tasks are accomplished in business through different communicative strategies. Literature review: This paper focuses on engineers’ and technical managers’ needs and challenges in professional and intercultural communication where English is used as a business lingua franca (BELF) in multimodal meetings. While multimodal conversation and discourse analytic studies highlight the dynamic nature of meeting interaction, previous technical and professional communication and BELF research on multimodality is limited. Research questions: 1. How do technical managers use multimodal resources to articulate their ideas in BELF meetings with their peers? 2. How does the use of multimodal resources contribute to the construction of shared meaning in explanatory, consensus-seeking, and solution-finding communication? Methodology: This study reports on two case studies and multimodal discourse analysis of video-recorded meetings among technical managers and their peers in four companies. The use of multimodal resources is analyzed in explanatory, consensus-seeking, and solution-finding communication. Results and conclusions: In BELF meetings, assemblages of spoken language, gestures, tools, whiteboard, and documents contribute to constructing shared meaning. This study has implications for global professional and engineering communication. Future research should further examine multimodality in BELF meetings. [ABSTRACT FROM AUTHOR]

The telecommunications industry is demanding more technical and non-technical skills as well as increased creativity and flexibility from its next generation workforce. University education provides strong fundamental background, but can offer only limited hands-on experience with cutting-edge technology, development tools, and processes as part of the broader curriculum. Whereas gaining relevant experience is generally possible for theses, we propose a new educational methodology and tools that can be used in classes at any degree level. Specifically, we introduce a hands-on learning methodology that consists of collaborative and competitive modules and apply it for teaching modern wireless communications. It has seven learning stages that follow the principles of project-based learning. The evaluation requires special attention, and several mechanisms are discussed for evaluating students and the methodology. Enabled by software radio technology, we present a practical learning environment and open source software tools that facilitate developing many of the needed technical and soft skills and demonstrate the suitability of the proposed methodology as applied to the undergraduate Software Radio Engineering class at Barcelona Tech-UPC. [ABSTRACT FROM AUTHOR]

Distributed graph processing systems such as Pregel, PowerGraph, or GraphX gained popularity due to their superior performance of data analytics on graph-structured data. These systems employ partitioning algorithms to parallelize graph analytics while minimizing inter-partition communication. Recent partitioning algorithms, however, unrealistically assume a uniform and constant amount of data exchanged between graph vertices (i.e., uniform vertex traffic) and homogeneous network costs between workers hosting the graph partitions. This leads to suboptimal partitioning decisions and inefficient graph processing. To this end, we developed GrapH, the first graph processing system using vertex-cut graph partitioning that considers both, diverse vertex traffic and heterogeneous network costs. The main idea is to avoid frequent communication over expensive network links using an adaptive edge migration strategy. Our evaluations show an improvement of 10 percent in graph processing latency and 60 percent in communication costs compared to state-of-the-art partitioning approaches. [ABSTRACT FROM AUTHOR]

We consider the question of interactive communication, in which two remote parties perform a computation, while their communication channel is (adversarially) noisy. We extend here the discussion into a more general and stronger class of noise, namely, we allow the channel to perform insertions and deletions of symbols. These types of errors may bring the parties “out of sync,” so that there is no consensus regarding the current round of the protocol. In this more general noise model, we obtain the first interactive coding scheme that has a constant rate and tolerates noise rates of up to $1/18- \varepsilon $ . To this end, we develop a novel primitive we name edit-distance tree code. The edit-distance tree code is carefully designed to replace the Hamming distance constraints in Schulman’s tree codes (IEEE Trans. Inf. Theory, 1996), with a stronger edit-distance requirement. [ABSTRACT FROM PUBLISHER]

Communication complexity investigates the amount of communication needed for two or more players to determine some joint function of their private inputs. For many interesting functions, the communication complexity can be much smaller than basic information theoretic measures associated with the players’ inputs such as the input length, the entropy, or even the conditional entropy. Communication complexity of many functions reduces further when the players share randomness. Classical works studied the communication complexity of functions when the interacting players share randomness perfectly, i.e., they get identical copies of randomness from a common source. This paper considers the variant of this question when the players share randomness imperfectly, i.e., when they get noisy copies of the randomness produced by some common source. Our main result shows that any function that can be computed by a $k$ -bit protocol in the perfect sharing model has a 2^{k} -bit protocol in the setting of imperfectly shared randomness and such an exponential growth is necessary. Our upper bound relies on ideas from locality sensitive hashing, while lower bounds rely on hypercontractivity and a new invariance principle tailored for communication protocols. [ABSTRACT FROM PUBLISHER]

We prove that the ensemble of the nested coset codes built on finite fields achieves the capacity of arbitrary discrete memoryless point-to-point channels. Exploiting its algebraic structure, we develop a coding technique for communication over general discrete multiple access channel with channel state information distributed noncausally at the transmitters. We build an algebraic coding framework for this problem using the ensemble of Abelian group codes and, thereby, derive a new achievable rate region. We identify non-additive and non-symmetric examples for which the proposed achievable rate region is strictly larger than the one achievable using random unstructured codes. [ABSTRACT FROM PUBLISHER]

The nonlinear complexity of a periodic sequence s is the length of the shortest feedback shift register that can generate s, and its value is upper bounded by the least period of s minus 1. In this paper, a recursive approach that generates all periodic sequences with maximum nonlinear complexity is presented, and the total number of such sequences is determined. The randomness properties of these sequences are also examined. [ABSTRACT FROM PUBLISHER]

Device-to-device (D2D) communication permits direct communication between devices, thereby it provides performance gain for traditional cellular networks. In this paper, we investigate how to improve the performance of D2D communication while satisfying the delay constraint for practical applications. Closed-form expressions are derived for trade-offs among system performance, such as successful transmission probability, transmission capacity, delay constraint, and energy consumption. In addition, two schemes are proposed to improve the performance for D2D communication under a given delay constraint. First, an optimal transmission scheme is proposed in which the transmission of user equipment (UE) can be scheduled adaptively to have the best successful transmission probability, whereas the D2D link satisfies the delay constraint. Second, a delay assignment scheme is proposed in which delay is adaptively assigned for each hop to achieve the maximum capacity when the network employs multihop D2D communication. Simulation results show that the adaptive transmission scheme improves the successful transmission probability (e.g., increased by 13 times when the source density is \text10^-4) compared with the fixed-probability transmission scheme, although it can satisfy the delay constraints for different applications. Furthermore, compared with the fixed delay assignment scheme, the network capacity can be improved up to 50% by the proposed scheme with proper delay assignment for each hop. [ABSTRACT FROM AUTHOR]

Motivated by the promising benefits of dynamic time division duplex (TDD), in this paper, we use a unified framework to investigate both the technical issues of applying dynamic TDD in homogeneous small-cell networks (HomSCNs) and the feasibility of introducing dynamic TDD into heterogeneous networks (HetNets). First, HomSCNs are analyzed, and a small-cell base-station (BS) scheduler that dynamically and independently schedules downlink (DL) and uplink (UL) subframes is presented, such that load balancing between the DL and UL traffic can be achieved. Moreover, the effectiveness of various interlink interference mitigation (ILIM) schemes and their combinations is systematically investigated and compared. Moreover, the interesting possibility of partial interference cancelation (IC) is also explored. Second, based on the proposed schemes, the joint operation of dynamic TDD together with cell range expansion (CRE) and almost blank subframe (ABS) in HetNets is studied. In this regard, scheduling polices in small cells and an algorithm to derive the appropriate macrocell traffic offload and ABS duty cycle under dynamic TDD operation are proposed. Moreover, the full IC and the partial IC schemes are investigated for dynamic TDD in HetNets. The user-equipment (UE) packet throughput performance of the proposed/discussed schemes is benchmarked using system-level simulations. [ABSTRACT FROM AUTHOR]

Achievable degrees of freedom (DoF) of the large-scale interfering two-way relay network is investigated. The network consists of $K$ pairs of communication nodes (CNs) and $N$ relay nodes (RNs). It is assumed that $K\ll N$ and that each pair of CNs communicates with each other through one of the $N$ RNs without a direct link between them. Interference among RNs is also considered. Assuming local channel state information (CSI) at each RN, a distributed and opportunistic RN selection technique is proposed for the following three promising relaying protocols: amplify-and-forward (AF), decode-and-forward (DF), and compute-and-forward (CF) relaying protocols. As a main result, the asymptotically achievable DoF is characterized as $N$ increases for the three relaying protocols. In particular, a sufficient condition on $N$ required to achieve the certain DoF of the network is analyzed. Through extensive simulations, it is shown that the proposed RN selection techniques outperform conventional schemes in terms of achievable rate, even in practical communication scenarios. Note that the proposed technique operates with a distributed manner and requires only local CSI, leading to easy implementation for practical wireless systems. [ABSTRACT FROM AUTHOR]

Information-centric wireless network virtualization enables the sharing of not only the infrastructure but also the content among different service providers, enabling the gain of not only virtualization but in-network caching as well. In this paper, we propose a novel framework with information-centric wireless virtualization and device-to-device (D2D) communications, which enables content caching not only in the air but in the mobile device as well. Moreover, the content is virtualized and can be shared by users from different virtual service providers. In this framework, we formulate the virtual resource allocation and caching strategies as a joint optimization problem, considering the gain of not only virtualization but of caching in the proposed information-centric wireless network virtualization architecture with D2D communications as well. In addition, to reduce computational complexity and signaling overhead, we propose a distributed algorithm to solve the formulated problem based on recent advances in alternating direction method of multipliers (ADMM), in which different parties only need to solve their own problems without the exchange of channel state information (CSI) with fast convergence rate. Extensive simulations are conducted with different system parameters to show the effectiveness of the proposed scheme. [ABSTRACT FROM PUBLISHER]

A table of contents for the issue is presented.

Lattice codes are known to outperform random codes for certain networks, especially in the Gaussian two-way relay channels (GTWRCs) where lattice codes are able to exploit their linearity. As an extension of the GTWRC, in this paper, we consider the asymmetric Gaussian two-way line network where two nodes exchange their messages through multiple relays. We first investigate the capacity region of the full-duplex two-way two-relay line network. The results can be extended to an arbitrary number of relays and to half-duplex scenarios. This channel consists of four nodes: $1\leftrightarrow 2\leftrightarrow 3\leftrightarrow 4$ , where nodes 1 and 4 with the help of two full-duplex relays, i.e., nodes 2 and 3, exchange their messages with each other. Using lattice codes, we design a novel scheme that allows the relay nodes to send the data in both directions simultaneously under an asymmetric rate region. In the proposed scheme, each relay decodes the sum of lattice points and then re-encodes it into another lattice codeword (which satisfies the transmit power constraint at the relay). It is shown that the proposed scheme achieves the capacity region of asymmetric two-way line network within 0.5 bit independent of the number of relays. [ABSTRACT FROM PUBLISHER]

A cavity-backed triangular-complimentary-split-ring-slot (TCSRS) antenna based on substrate integrated waveguide (SIW) is proposed in this communication. Proposed antenna element is designed and implemented at 28 and 45 GHz for the fifth generation (5G) of wireless communications. The principle of the proposed antenna element is investigated first then the arrays with two and four elements are designed for high-gain operation. Antennas prototype along with their arrays are fabricated using standard printed circuit board (PCB) process at both frequencies—28 and 45 GHz. Measured result shows that the 16.67% impedance bandwidth at 28 GHz and 22.2% impedance bandwidth at 45 GHz is achieved, while maintaining the same substrate height at both frequencies. The measured peak gains of the $2\times 2$ antenna array at 30 or 50 GHz are 13.5 or 14.4 dBi, respectively. [ABSTRACT FROM PUBLISHER]

For a discrete or a continuous source model, we study the problem of secret-key generation with one round of rate-limited public communication between two legitimate users. Although we do not provide new bounds on the wiretap secret-key (WSK) capacity for the discrete source model, we use an alternative achievability scheme that may be useful for practical applications. As a side result, we conveniently extend known bounds to the case of a continuous source model. Specifically, we consider a sequential key-generation strategy, that implements a rate-limited reconciliation step to handle reliability, followed by a privacy amplification step performed with extractors to handle secrecy. We prove that such a sequential strategy achieves the best known bounds for the rate-limited WSK capacity (under the assumption of degraded sources in the case of two-way communication). However, we show that, unlike the case of rate-unlimited public communication, achieving the reconciliation capacity in a sequential strategy does not necessarily lead to achieving the best known bounds for the WSK capacity. Consequently, reliability and secrecy can be treated successively but not independently, thereby exhibiting a limitation of sequential strategies for rate-limited public communication. Nevertheless, we provide scenarios for which reliability and secrecy can be treated successively and independently, such as the two-way rate-limited SK capacity, the one-way rate-limited WSK capacity for degraded binary symmetric sources, and the one-way rate-limited WSK capacity for Gaussian degraded sources. [ABSTRACT FROM PUBLISHER]

This article proposes a multidimensional context-aware social network architecture, which aims to provide a mobile ecosystem to enable context awareness in the development and utilization of mobile crowdsensing applications. This mobile ecosystem is constructed to provide context awareness capabilities for different roles (i.e., users or developers) in the system and facilitate interactions between them. This system can ease the development of context-aware mobile applications, and enable context-aware mobile crowdsensing considering environmental, personal, and social information. We present a flow of context-aware solutions designed on this system, and highlight the orchestrations and advantages of different context-aware schemes in the system for different types of users (requesters and participants) in mobile crowdsensing. We demonstrate the feasibility of the proposed mobile ecosystem by presenting a novel contextaware mobile crowdsensing application called Smart City, and evaluate the system performance based on this application. [ABSTRACT FROM PUBLISHER]

Research problem: Indirect communication is prevalent in business communication practices. For information systems (IS) projects that require professionals from multiple disciplines to work together, the use of indirect communication may hinder successful design, implementation, and maintenance of these systems. Drawing on the Speech Act Theory (SAT), this study investigates how direct and indirect speech acts may influence language comprehension in the setting of communication problems inherent in IS projects. Research questions: (1) Do participating subjects, who are IS professionals, differ in their comprehension of indirect and direct speech acts? (2) Do participants display different attention processes in their comprehension of indirect and direct speech acts? (3) Do participants' attention processes influence their comprehension of indirect and direct speech acts? Literature review: We review two relevant areas of theory—polite speech acts in professional communication and SAT. First, a broad review that focuses on literature related to the use of polite speech acts in the workplace and in information system (IS) projects suggests the importance of investigating speech acts by professionals. In addition, the SAT provides the theoretical framework guiding this study and the development of hypotheses. Methodology: The current study uses a quantitative approach. A between-groups experiment design was employed to test how direct and indirect speech acts influence the language comprehension of participants. Forty-three IS professionals participated in the experiment. In addition, through the use of eye-tracking technology, this study captured the attention process and analyzed the relationship between attention and comprehension. Results and discussion: The results show that the directness of speech acts significantly influences participants' attention process, which, in turn, significantly affects their comprehension. In addition, the findings indicate that indirect speech acts, if employed by IS professionals to communicate with others, may easily be distorted or misunderstood. Professionals and managers of organizations should be aware that effective communication in interdisciplinary projects, such as IS development, is not easy, and that reliance on polite or indirect communication may inhibit the generation of valid information. [ABSTRACT FROM PUBLISHER]

Communications is becoming increasingly important to the operation of protection and control schemes. Although offering many benefits, using standards-based communications, particularly IEC 61850, in the course of the research and development of novel schemes can be complex. This paper describes an open-source platform which enables the rapid prototyping of communications-enhanced schemes. The platform automatically generates the data model and communications code required for an intelligent electronic device to implement a publisher-subscriber generic object-oriented substation event and sampled-value messaging. The generated code is tailored to a particular system configuration description (SCD) file, and is therefore extremely efficient at runtime. It is shown here how a model-centric tool, such as the open-source Eclipse Modeling Framework, can be used to manage the complexity of the IEC 61850 standard, by providing a framework for validating SCD files and by automating parts of the code generation process. The flexibility and convenience of the platform are demonstrated through a prototype of a real-time, fast-acting load-shedding scheme for a low-voltage microgrid network. The platform is the first open-source implementation of IEC 61850 which is suitable for real-time applications, such as protection, and is therefore readily available for research and education. [ABSTRACT FROM PUBLISHER]

Input/output delays in a control system can pose significant impediments to the stabilization problem and potentially degrade the performance of the closed-loop system. In this paper, we study the classical set-point control problem for rigid robots with input–output communication delays in the closed-loop system. We demonstrate that if there are transmission delays between the robotic system and the controller, then the use of the scattering variables can stabilize an otherwise unstable system for arbitrary unknown constant delays. It is also demonstrated that the proposed algorithm results in guaranteed set-point tracking. In the case of time-varying delays, scattering variables together with additional gains can be utilized to stabilize the closed-loop system that is composed of the robotic manipulator and the controller. Furthermore, a scattering representation-based design with position feedback is proposed to improve closed-loop performance under time-varying delays. The proposed algorithms are validated via experiments in this paper. [ABSTRACT FROM AUTHOR]

We consider a communication network and study the problem of designing a high-throughput and low-delay scheduling policy that only requires a polynomial amount of computation at each time step. The well-known maximum weight scheduling policy, proposed by Tassiulas and Ephremides (1992), has favorable performance in terms of throughput and delay but, for general networks, it can be computationally very expensive. A related randomized policy proposed by Tassiulas (1998) provides maximal throughput with only a small amount of computation per step, but seems to induce exponentially large average delay. These considerations raise some natural questions. Is it possible to design a policy with low complexity, high throughput, and low delay for a general network? Does Tassiulas' randomized policy result in low average delay? In this paper, we answer both of these questions negatively. We consider a wireless network operating under two alternative interference models: (a) a combinatorial model involving independent set constraints and (b) the standard SINR (signal to interference noise ratio) model. We show that unless \bf NP\subseteq \bf BPP (or \bf P =\bf NP for the case of determistic arrivals and deterministic policies), and even if the required throughput is a very small fraction of the network's capacity, there does not exist a low-delay policy whose computation per time step scales polynomially with the number of queues. In particular, the average delay of Tassiulas' randomized algorithm must grow super-polynomially. To establish our results, we employ a clever graph transformation introduced by Lund and Yannakakis (1994). [ABSTRACT FROM AUTHOR]

Let X and y be finite nonempty sets and (X, Y) a pair of random variables taking values in X x Y. We consider communication protocols between two parties, ALICE and BOB, for generating X and Y. ALICE is provided an x ∈ X generated according to the distribution of X, and is required to send a message to BOB in order to enable him to generate y ∈ Y, whose distribution is the same as that of Y|X = x. Both parties have access to a shared random string generated in advance. Let T[X : Y] be the minimum (over all protocols) of the expected number of bits ALICE needs to transmit to achieve this. We show that I[X : Y] ≤ T[X : Y] ≤ I [X : Y] + 2 log2(I[X : Y] + 1) + 0(1). We also consider the worst case communication required for this problem, where we seek to minimize the average number of bits ALICE must transmit for the worst case x ∈ X. We show that the communication required in this case is related to the capacity C(E) of the channel E, derived from (X, Y), that maps x ∈ X to the distribution of Y|X = x. We also show that the required communication T(E) satisfies C(E) ≤ T(E) ≤ C(E) + 2log2(C(E) + 1) + 0(1). Using the first result, we derive a direct-sum theorem in communication complexity that substantially improves the previous such result shown by Jain, Radhakrishnan, and Sen [In Proc. 30th International Colloquium of Automata, Languages and Programming (ICALP), ser. Lecture Notes in Computer Science, vol. 2719.2003, pp. 300-315]. These results are obtained by employing a rejection sampling procedure that relates the relative entropy between two distributions to the communication complexity of generating one distribution from the other. [ABSTRACT FROM AUTHOR]

The utility of limited feedback for coding over an individual sequence of discrete memoryless channels is investigated. This study complements recent results showing how limited or noisy feedback can boost the reliability of communication. A strategy with fixed input distribution P is given that asymptotically achieves rates arbitrarily close to the mutual information induced by P and the state-averaged channel. When the capacity-achieving input distribution is the same over all channel states, this achieves rates at least as large as the capacity of the state-averaged channel, sometimes called the empirical capacity. [ABSTRACT FROM AUTHOR]

Composite multipath fading/shadowing environments are frequently encountered in different realistic scenarios. These channels are generally modeled as a mixture of Nakagamim multipath fading and log-normal shadowing. The resulting composite probability density function (pdf) is not available in closed form, thereby making the performance evaluation of communication links in these channels cumbersome. In this paper, we propose to model composite channels by the G- distribution. This pdf arises when the log-normal shadowing is substituted by the Inverse-Gaussian one. This substitution will prove to be very accurate for several shadowing conditions. In this paper we conduct a performance evaluation of single-user communication systems operating in a composite channel. Our study starts by deriving an analytical expression for the outage probability. Then, we derive the moment generating function of the G-distribution, hence facilitating the calculation of average bit error probabilities. We also derive analytical expressions for - the channel capacity for three adaptive transmission techniques, namely, i) optimal rate adaptation with constant power, ii) optimal power and rate adaptation, and iii) channel inversion with fixed rate. [ABSTRACT FROM AUTHOR]

We propose a distortion optimal rate allocation algorithm for robust transmission of embedded bitstreams over noisy channels. The algorithm is based on the backward application of a Viterbi-like algorithm to a search trellis, and can be applied to both scenarios of fixed and variable channel packet length problems, referred to as FPP and VPP, respectively. For the VPP, the complexity of the algorithm is comparable to the well-known dynamic programming approach of Chande and: Farvardin. For the FPP, where no low-complexity algorithm is known, the complexity of the proposed algorithm is O(N[sup2]), where N is the number of transmitted packets. [ABSTRACT FROM AUTHOR]

The uncertainty, due to random noise, of the measurements made with a mixer-based nonlinear vector network analyzer are analyzed. An approximate covariance matrix corresponding to the measurements is derived that can be used for fitting models and maximizing the dynamic range in the measurement setup. The validity of the approximation is verified with measurements. [ABSTRACT FROM AUTHOR]

An inner bound on the deterministic-code capacity region of the two-user discrete memoryless arbitrarily varying general broadcast channel (AVGBC) was characterized by Jahn, assuming that the common message capacity is nonzero; however, he did not indicate how one could decide whether the latter capacity is positive. Csiszár and Narayan's result for the single-user arbitrarily varying channel (AVC) establishes the missing part in Jahn's characterization. Nevertheless, being based on Ahlswede's elimination technique, Jahn's characterization is not applicable for symmetrizable channels under state constraint. Here, the various notions of symmetrizability for the two-user broadcast AVC are defined. Sufficient non-symmetrizability condition that renders the common message capacity of the AVGBC positive is identified using an approach different from Jahn's. The decoding rules we use establish an achievable region under state and input constraints for the family of degraded message sets codes over the AVGBC. [ABSTRACT FROM AUTHOR]

Achievable rates over the discrete memoryless relay channel with partial feedback configurations are proposed. Specifically, we consider partial feedback from the receiver to the sender as well as partial feedback from the relay to the sender. These achievable rates are calculated for the general Gaussian and the Z relay channels and are shown to improve on the known one-way achievable rates. [ABSTRACT FROM AUTHOR]

Along with the ever-growing Web comes the proliferation of objectionable content, such as sex, violence, racism, etc. We need efficient tools for classifying and filtering undesirable Web content. In this paper, we investigate this problem and describe WebGuard, an automatic machine learning-based pornographic Web site classification and filtering system. Unlike most commercial filtering products, which are mainly based on textual content-based analysis such as indicative keywords detection or manually collected black list checking, WebGuard relies on several major data mining techniques associated with textual, structural content-based analysis, and skin color related visual content-based analysis as well. Experiments conducted on a testbed of 400 Web sites including 200 adult sites and 200 nonpornographic ones showed WebGuard's filtering effectiveness, reaching a 97.4 percent classification accuracy rate when textual and structural content-based analysis was combined with visual content-based analysis. Further experiments on a black list of 12,311 adult Web sites manually collected and classified by the French Ministry of Education showed that WebGuard scored a 95.62 percent classification accuracy rate. The basic framework of WebGuard can apply to other categorization problems of Web sites which combine, as most of them do today, textual and visual content. [ABSTRACT FROM AUTHOR]

As feature sizes are becoming smaller, wire delays are becoming very critical. Clustering is a popular decentralization approach to reduce the impact of shrinking technologies on clock speed. In this approach, the centralized instruction window is replaced with multiple smaller windows, called clusters (PEs). The performance of these clustered processors depends on the amount of inter-PE communication and load imbalance incurred by the distribution algorithm used to distribute instructions among the PEs. In this paper, we investigate a novel approach of reducing the impact of inter-PE communication latency, while preserving good load balance. The basic idea is to selectively replicate instructions in those PEs where their results are required. The replication is done based on heuristics that weigh the potential benefits of replication. We found that, with instruction replication, the IPC of a clustered processor is significantly higher than that obtained without instruction replication and is within just 8 percent of that of a superscalar configuration with a centralized instruction scheduler. [ABSTRACT FROM AUTHOR]

Message Authentication Codes (MAC5) are valuable tools for ensuring the integrity of messages. MACs may be built around a universal hash function (NH) which was explored in the construction of UMAC. In this paper, we use a variation on NH called WH. WH reaches optimality in the sense that it is universal with half the hash length of NH and it achieves perfect serialization in hardware implementation. We achieved substantial power savings of up to 59 percent and a speedup of up to 7.4 times over NH. Moreover, we show how the technique of multihashing and the Toeplitz approach can be combined to reduce the power and energy consumption even further while maintaining the same security level with a very slight increase in the amount of the key material. At low frequencies, the power and energy reductions are achieved simultaneously while keeping the hashing time constant. We developed formulae for estimation of the leakage and dynamic power consumptions as well as the energy consumption based on the frequency and the Toeplitz parameter t. We introduce a powerful method for scaling WH according to specific energy and power consumption requirements. Our implementation of WH-1 6 consumes only 2.95 μW at 500 khz. It can therefore be integrated into a self-powered device. [ABSTRACT FROM AUTHOR]

We study a class of pseudo-chaotic spread spectrum systems for secure communication over additive white Gaussian noise (AWGN) channels, whereby a symbol stream is linearly modulated on a spreading sequence generated by iterating an initial condition through a suitably chosen chaotic map. We compare the uncoded probability of error (Pr(∊)) attainable by intended receivers that know the initial condition to the associated Pr(∊) of unintended receivers that know the modulation scheme but not the initial condition. The sensitive dependence of chaotic sequences on initial conditions, together with the presence of channel noise, can be exploited to provide substantially lower Pr(∊) to intended than to unintended receivers. We develop computationally efficient methods for obtaining tight bounds on the best Pr (∊) performance of intended and unintended receivers. In the process, we identify chaotic map attributes that affect the relative Pr(∊) advantages provided to intended receivers and develop methods for designing maps that achieve a target gap between the intended and unintended receiver Pr(∊). [ABSTRACT FROM AUTHOR]

The generic framing procedure (GFP) is a new standard that has been developed to overcome data transport inefficiencies or deficiencies with the existing ATM and packet over SONET/SDH protocols. Transparent GFP (GFP-T) is an extension to GFP developed to provide efficient low-latency support for high-speed WAN applications including storage area networks. Rather than handling data on a frame-by-frame (packet-by-packet) basis, GFP-T handles block-coded (e.g., 8B/10B) character streams. This article describes the GFP protocol along with technical considerations and applications for transparent GFP [ABSTRACT FROM PUBLISHER]

We discuss the generic framing procedure (GFP) in the context of emerging nontraditional data over transport applications. Coupled with complementary efforts to define virtual concatenation, automatic link capacity adjustment schemes, and distributed control planes for transport networks, we contend that GFP serves as the catalyst for efficient and standard data over transport service offerings [ABSTRACT FROM PUBLISHER]

The generic framing procedure (GFP) is a standardized traffic adaptation protocol for broadband transport applications. It provides an efficiency and QoS-friendly mechanism to map either a physical layer or logical link layer signal to a byte-synchronous channel. It also supports basic client control functions for client management purposes. This article presents a brief overview of GFP [ABSTRACT FROM PUBLISHER]

In ancient times, unless somebody was prepared to travel, man could only communicate as far as he could shout. Methods were then developed to enable communications to extend over longer distances, using trumpets, beacon fire, flags, etc. It was not until the inauguration of telegraphy (by W. Cooke and C. Wheatstone in England in 1839, and by S. Morse in the US in 1844) and telephony (by A. G. Bell in 1876), that electricity was utilized to facilitate commercial telecommunication service [1]?[2]. Then, for nearly 100 years, telecommunications was mainly about telephony and telegraphy and was based almost entirely on electrical engineering methods. From audio to radio signals, electro-mechanic to electronic technologies, analog to digital systems, and electronic to photonic devices; telecommunications has witnessed tremendous progress on numerous fronts. In terms of services and applications, telecommunications evolved in recent years to embrace cyber space, entertainment, and electronic commerce and business. [ABSTRACT FROM PUBLISHER]

Hwang and Lin introduced a new nonbiocking requirement for 2-cast traffic which imposes different requirements on different types of coexisting calls. The requirement is strictly nonblocking for point-to-point calls among the 2-cast traffic, and is rearrangeable for genuine 2-cast calls. We generalize the 2-cast calls to multicast calls and give a sufficient condition for such networks when the number of multicast calls is upper bounded. [ABSTRACT FROM AUTHOR]

A decade of research on traffic classification has provided various methodologies to investigate the traffic composition in data communication networks. Many variants or combinations of such methodologies have been introduced continuously to improve the classification accuracy and efficiency. However, the level of classification details is often bounded to identifying protocols or applications in use. In this article, we propose a fine-grained traffic classification scheme based on the analysis of existing classification methodologies. This scheme allows to classify traffic according to the functionalities in an application. In particular, we present a traffic classifier which utilizes a document retrieval technique and applies multiple signatures to detect the peer-to-peer application traffic according to different functionalities in it. We show that the proposed scheme can provide more in-depth classification results for analyzing user contexts. [ABSTRACT FROM PUBLISHER]

CURLING, a Content-Ubiquitous Resolution and Delivery Infrastructure for Next Generation Services, aims to enable a future content-centric Internet that will overcome the current intrinsic constraints by efficiently diffusing media content of massive scale. It entails a holistic approach, supporting content manipulation capabilities that encompass the entire content life cycle, from content publication to content resolution and, finally, to content delivery. CURLING provides to both content providers and customers high flexibility in expressing their location preferences when publishing and requesting content, respectively, thanks to the proposed scoping and filtering functions. Content manipulation operations can be driven by a variety of factors, including business relationships between ISPs, local ISP policies, and specific content provider and customer preferences. Content resolution is also natively coupled with optimized content routing techniques that enable efficient unicast and multicast- based content delivery across the global Internet. [ABSTRACT FROM PUBLISHER]

This article presents approaches to line narrative generation. Tale-Spin was one of the first linear narrative generators which used an inference rule engine to determine what the story-world characters would do in a noninteractive system. On the other hand, the Universe storytelling system used hierarchical planning to decompose high level plot fragments to generate more coherent narratives. Recently, Fabulist applies more formalized causal-dependency planning techniques to narrative generation.