ppxscal/embedding_network huggingface dataset:
Post-pass periodic register allocation to minimise loop unrolling degree
Authors: Mounira Bachir, Sid-Ahmed-Ali Touati, Albert Cohen
Venue: Proceedings of the 2008 ACM SIGPLAN-SIGBED conference on Languages, compilers, and tools for embedded systems (2008)

This paper solves an open problem regarding loop unrolling after periodic register allocation. Although software pipelining is a powerful technique to extract fine-grain parallelism, it generates reuse circuits spanning multiple loop iterations. These circuits require periodic register allocation, which in turn yield a code generation challenge, generally addressed through: (1) hardware support --- rotating register files --- deemed too expensive for embedded processors, (2) insertion of register moves with a high risk of reducing the computation throughput --- initiation interval (II) --- of software pipelining, and (3) post-pass loop unrolling that does not compromise throughput but often leads to unpractical code growth. The latter approach relies on the proof that MAXLIVE registers are sufficient for periodic register allocation (2; 3; 5); yet the only heuristic to control the amount of post-pass loop unrolling does not achieve this bound and leads to undesired register spills (4; 7). We propose a periodic register allocation technique allowing a software-only code generation that does not trade the optimality of the II for compactness of the generated code. Our idea is based on using the remaining registers: calling Rarch the number of architectural registers of the target processor, then the number of remaining registers that can be used for minimising the unrolling degree is equal to Rarch-MAXLIVE. We provide a complete formalisation of the problem and algorithm, followed by extensive experiments. We achieve practical loop unrolling degrees in most cases --- with no increase of the II --- while state-of-the-art techniques would either induce register spilling, degrade the II or lead to unacceptable code growth.
A service-oriented middleware for providing context awareness and notification
Authors: Luiz Olavo Bonino da Silva Santos, Peter Vink, Remco Poortinga van Wijnen
Venue: Proceedings of the 2007 ACM/IFIP/USENIX international conference on Middleware companion (2007)

In the last few years context awareness has emerged as an important element in distributed computing. It offers mechanisms that allow applications to be aware of their environment and enable these applications to adjust their behavior to the current context. Considering the dynamic nature of context, the data flow of relevant contextual information can be significant. In order to keep track of this information flow, a flexible service mechanism should be available for the client applications. In this document we propose a demonstration of the Awareness and Notification Service (ANS) middleware. ANS provides context-awareness capabilities to users and client applications. The conditions for the notification and the notification itself are defined in rules that users submit to the service by means of a convenient rule language.
Neural Network Based Biometric Personal Identification
Authors: Rahib H. Abiyev, Koray Altunkaya
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

This paper presents biometric personal identification based on iris recognition using neural networks. Personal identification system consists of localization of the iris region and generation of data set of iris images and then iris pattern recognition. In this paper, fast algorithm is proposed for the localization of the inner and outer boundaries of the iris region. Located iris is extracted from an eye image, and, after normalization and enhancement it is represented by a data set. Using this data set a neural network is applied for the classification of iris patterns. Results of simulations illustrate the effectiveness of the neural system in personal identification.
Very long distance wi-fi networks
Authors: Rob Flickenger, Steve Okay, Ermanno Pietrosemoli, Marco Zennaro, Carlo Fonda
Venue: Proceedings of the second ACM SIGCOMM workshop on Networked systems for developing regions (2008)

802.11 Wi-Fi technology is commonly used for creating wireless networks with a range of about one hundred meters. With careful planning and proper antennas, this same equipment can be used to make point-to-point links of hundreds of kilometers. This paper presents a successful 279 km link made by wireless experts in Venezuela, and a permanent 133 km test network in northern Italy for ongoing research.
The characteristic finite volume element method for the nonlinear convection-dominated diffusion problem
Authors: Fuzheng Gao, Yirang Yuan
Venue: Computers Mathematics with Applications (2008)

In modern numerical simulation of prospecting and exploiting oil-gas resources and environmental science, it is important to consider a numerical method for nonlinear convection-dominated diffusion problems. Based on actual conditions, such as the three-dimensional characteristics of large-scale science-engineering computation, we present a kind of characteristic finite volume element method. Some techniques, such as calculus of variations, commutating operators, the theory of prior estimates and techniques, are adopted. Suboptimal order error estimate in L^2 norm and optimal order error estimate in H^1 norm are derived to determine the errors for the approximate solution. Numerical results are presented to verify the performance of the scheme.
Study on component temperatures inversion using satellite remotely sensed data
Authors: X. Song, Y. Zhao
Venue: International Journal of Remote Sensing (2007)

Because of the low spatial resolution of MODIS data, it is important to decompose mixed pixels to retrieve component temperatures using thermal infrared bands. Grasslands with different coverage conditions are prominent in the area under study. Because of the simple vegetation structure, radiation is less influenced by vegetation shade. If the internal structure of the component parts of the mixed pixel is ignored, the total radiation emitted by the mixed pixel is approximately the sum of the radiation emitted by each component part of the pixel, weighted according to the percentage area of each component part. Vegetation/soil component temperatures based on the sub-pixel scale are inverted using a constrained optimization algorithm-the genetic algorithm. The study not only broadens the application of the linear spectral mixing model but also develops a practical method for component temperatures retrieval from MODIS satellite data. The results provide more precise parameters for estimation of land surface energy balance and evapotranspiration.
Drift Characterization of Intra Prediction and Quantization in H.264
Authors: Athanasios Leontaris, Alexis M. Tourapis
Venue: Proceedings of the Data Compression Conference (2008)

The combination of intra prediction, transform, and quantization in the H.264/AVC video coding standard offers high compression performance in picture areas where inter prediction is unavailable or fails. Motivated from coding experiments with the reference software that resulted in significant visual distortion with certain types of content, we investigated intra prediction further. Intra prediction may propagate distortion to subsequent blocks or macroblocks. As a result, rate-distortion optimized mode decision needs to account for this distortion. Furthermore, rounding operations in H.264/AVC accumulate small but non-trivial errors. This is especially true for the encoding process of the 16×16 intra prediction mode, which involves a combination of DCT and Hadamard transforms. We investigate, theoretically and experimentally, the problem of visual distortion caused by sub-optimal intra prediction coding decisions by modeling distortion propagation across subsequent blocks. We propose two algorithms that address the problem.
High-performance timing simulation of embedded software
Authors: Jürgen Schnerr, Oliver Bringmann, Alexander Viehl, Wolfgang Rosenstiel
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

This paper presents an approach for cycle-accurate simulation of embedded software by integration in an abstract SystemC model. Compared to existing simulation-based approaches, we present a hybrid method that resolves performance issues by combining the advantages of simulation-based and analytical approaches. In a first step, cycle-accurate static execution time analysis is applied at each basic block of a cross-compiled binary program using static processor models. After that, the determined timing information is back-annotated into SystemC for fast simulation of all effects that can not be resolved statically. This allows the consideration of data dependencies during run-time and the incorporation of branch prediction and cache models by efficient source code instrumentation. The major benefit of our approach is that the generated code can be executed very efficiently on the simulation host with approximately 90% of the speed of the untimed software without any code instrumentation.
Parallelization of Low-Level Computer Vision Algorithms on Clusters
Authors: Sanjay Kadam
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

In this paper we present parallel implementations of some representative low level vision algorithms on a cluster of workstations. These include convolution operation and the image restoration algorithm using Markov random field models. The convolution operation has been parallelized using theFarmer-Worker paradigm, while the image restoration algorithm has been parallelized through the Master-Worker pattern. Parallel implementations of both these algorithms have shown promising results, where the observed speedups are reasonably close to the ideal speedups. The parallel convolution operation has shown good scalability with respect to the problem size and number of processors used in parallelization. The paper elaborates on different parallelization results of the convolution operation observed after varying the image size, mask size and processor load on individual workstations. The image restoration algorithm is communication intensive. However, as the computing time between successive communications at each worker process is relatively high, the actual speedups observed are very close to the ideal speedups in this algorithm.
Stability of multi-path dual congestion control algorithms
Authors: Thomas Voice
Venue: IEEE/ACM Transactions on Networking (TON) (2007)

This paper investigates fair, scalable, stable congestion controls which achieve high bandwidth utilization over networks operating multi-path routing. It aims to take advantage of path diversity to achieve efficient bandwidth allocation without causing instability. We develop a multi-path extension to the dual algorithm, which takes into consideration path diversity when evaluating fairness. This algorithm is shown to be globally stable in the absence of propagation delays and a sufficient condition for local stability, for the case when heterogeneous propagation delays are present, is found. The sufficient condition we present is decentralized in the following sense: the gain parameter for each dynamic variable is restricted by the average round-trip time of packets passing through the link or source it represents, but not by the round-trip times of any other packets. This leads to a highly scalable parameter choice scheme. Gain parameters are calculated from local information which is independent of the state of the algorithm, and our delay stability condition is satisfied. The models considered apply to networks consisting of arbitrary interconnections of sources and links with arbitrary heterogeneous propagation delays.
Modeling crosstalk in statistical static timing analysis
Authors: Ravikishore Gandikota, David Blaauw, Dennis Sylvester
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

Increasing process variation in the nanometer regime motivates the use of statistical static timing analysis tools for timing verification. As device dimensions get smaller, signal integrity effects such as crosstalk noise become more significant. Therefore, it is necessary to accurately model the impact of crosstalk noise on the circuit delay. Process variations cause variability in the crosstalk alignment which leads to the variability in the delay noise. However, most of the existing approaches model delay noise as a worst-case deterministic quantity. In this work, we capture the variability of delay noise by first deriving the closed-form expressions of mean and standard deviation of the delay noise distribution. Next, we obtain the correlation information of the delay noise and use it to represent the delay noise distribution in canonical form. Delay noise, in canonical form, can easily be integrated with existing SSTA tools. We show experimental results that verify the accuracy of our approach.
Securing vehicular ad hoc networks
Authors: Maxim Raya Jean-Pierre Hubaux
Venue: Journal of Computer Security (2007)

Vehicular networks are very likely to be deployed in the coming years and thus become the most relevant form of mobile ad hoc networks. In this paper, we address the security of these networks. We provide a detailed threat analysis and devise an appropriate security architecture. We also describe some major design decisions still to be made, which in some cases have more than mere technical implications. We provide a set of security protocols, we show that they protect privacy and we analyze their robustness and efficiency.
An Integrated Node Behavior Model for Office Scenarios
Authors: Johannes Lessmann, Sascha Lutters
Venue: Proceedings of the 41st Annual Simulation Symposium (anss-41 2008) (2008)

For realistic simulations of ad hoc networks, the movements of the participating nodes must be considered. Many models have been proposed which generate movement patterns based on nodes' roles and activities. However, previous models mostly consider node activities individually for each node, making it difficult to precisely model joint activities. While advanced previous models are either based on the notion of schedules or on state machines, we propose a hybrid approach which combines the flexibility of the latter with the ability of the former to express time constraints. Further, as opposed to previous work, our model allows nodes to assume multiple roles and provides an intuitive way to reconcile their potentially conflicting schedules and state machines. Our model also considers the on/off behavior of nodes which is very important to evaluate adaptivity of protocols to node joins and failures under realistic conditions. A major contribution of our work is further that we take into account the fact that mobility, on/off patterns and traffic generation in a network cannot be modeled independently. Our comprehensive model is the first to include all three parts in one consistent form. Finally, it introduces the notion of home and preferred positions which allows very precise modeling of the general node distribution and positioning in an office scenario.
Identifying a hierarchy of bipartite subgraphs for web site abstraction
Authors: William K. Cheung, Yuxiang Sun
Venue: Web Intelligence and Agent Systems (2007)

The Web is transforming from a merely information dissemination platform towards a distributed knowledge-based platform for supporting complex problem solving. However, the existing Web contains a large amount of knowledge which is only tagged using layout related markups, making them hard to be discovered and used. In this paper, we purpose to model semantic-rich and self-contained knowledge units embedded in a web site as a mixture of bipartite sub-graphs and to extract the subgraphs as the web site abstraction via hyperlink structure and file hierarchy analysis. A recursive algorithm, named ReHITS, is derived which can identify bipartite sub-graphs with a hierarchical organization. Each identified sub-graph contains a set of associated authorities and hubs as its summarized semantic description. The effectiveness of the algorithm has been evaluated using three real web sites (containing &sim; 10000 web pages) with promising results. Detailed interpretation of the experimental results and qualitative comparison with other related work are also included.
Minimum entropy control of nonlinear ARMA systems over a communication network
Authors: Jianhua Zhang, Hong Wang
Venue: Neural Computing and Applications (2008)

In this paper, the entropy concept has been utilized to characterize the uncertainty of the tracking error for nonlinear ARMA stochastic systems over a communication network, where time delays in the communication channels are of random nature. A recursive optimization solution has been developed. In addition, an alternative algorithm is also proposed based on the probability density function of the tracking error, which is estimated by a neural network. Finally, a simulation example is given to illustrate the efficiency and feasibility of the proposed approach.
Scheduling Strategy of Subtask Decomposed
Authors: Benting Wan
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

The scheduling strategy of subtask decomposed (Sub-DC) is presented in this article, which includes two parts.The first part is layered transaction of DAG (DirectedAcyclic Graph), which all subtasks are divided intodifferent layers according to precedence relation; Thesecond part is task assignation, in the first, Min-Minscheduling strategy is used to assign subtasks of one layerto each computer of system; after subtasks of one layerare assigned, load balancing strategy is used todynamically adjusted system load, which makes use ofcharacter of subtasks decomposed and makes one layersubtasks are assigned better reason; then layer-by-layersubtasks are assigned using the same method. The Sub-DC not only makes subtasks of each layer be executed asquickly as possible, but also makes the application beexecuted in shorter time. The implement result shows thatthe Sub-DC is better than the level-by-level schedulingstrategy (Sub-Lev).
Design and Implementation of a Dual-Camera Wireless Sensor Network for Object Retrieval
Authors: Dan Xie, Tingxin Yan, Deepak Ganesan, Allen Hanson
Venue: Proceedings of the 7th international conference on Information processing in sensor networks (2008)

This paper presents the design and implementation of a dual-camera sensor network that can be used as a memory assistant tool for assisted living. Our system performs energy-efficient object detection and recognition of commonly misplaced objects. The novelty in our approach is the ability to tradeoff between recognition accuracy and computational efficiency by employing a combination of low complexity but less precise color histogram-based image recognition together with more complex image recognition using SIFT descriptors. In addition, our system can seamlessly integrate feedback from the user to improve the robustness of object recognition. Experimental results reveal that our system is computation-efficient and adaptive to slow changes of environmental conditions
Verification of Unstructured Workflows via Propositional Logic
Authors: Qianhui Althea Liang, J. Leon Zhao
Venue: Proceedings of the Seventh IEEE/ACIS International Conference on Computer and Information Science (icis 2008) (2008)

The concept of unstructured workflows is useful for both research and practical purposes. While sometimes it is preferable to transform unstructured workflows into structured ones, unstructured workflows may be more meaningful to business people. Furthermore, transformation from unstructured to structured workflows may be troublesome at times. As such, it is important to be able to verify unstructured workflows directly. In this paper, we take a different perspective by focusing on the verification of unstructured workflows using a propositional-logic-based approach. We demonstrate that logic-based verification can derive similar results between an unstructured workflow and its corresponding structured workflow. We further develop a conceptual framework that characterizes the propositional logic approach to verification of unstructured workflows.
Rate and delay guarantees provided by Clos packet switches with load balancing
Authors: Aleksandra Smiljanic
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

The size of a single-hop cross-bar fabric is still limited by the technology, and the fabrics available on the market do not exceed the terabit capacity. A multihop fabric such as Clos network provides the higher capacity by using the smaller switching elements (SE). When the traffic load is balanced over the switches in a middle stage, all the traffic would get through the fabric, as long as the switch outputs are not overloaded. However, the delay that packets experience through the Clos switch depends on the granularity of flows that are balanced. We examine the maximum fabric utilization under which a tolerable delay is provided for various load balancing algorithms, and derive the general formula for this utilization in terms of the number of flows that are balanced. We show that the algorithms which balance flows with sufficiently coarse granularity provide both high fabric utilization and delay guarantees to the most sensitive applications. Since no admission control should be performed within the switch, the fast traffic-pattern changes can be accommodated in the proposed scalable architecture.
Energy Efficient Object Tracking in Sensor Networks by Mining Temporal Moving Patterns
Authors: Vincent S. Tseng, Kawuu W. Lin, Ming-Hua Hsieh
Venue: Proceedings of the 2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing (sutc 2008) (2008)

Object tracking sensor networks (OTSNs) have received extensive attentions for researches in recent years due to the wide applications. One important research issue in OTSNs is the energy saving strategy in considering the limited power of sensor nodes. The past studies on energy saving in OTSNs usually considered the movement behavior of objects as randomness. However, in some real applications, the object movement behavior carries certain patterns instead of randomness completely. In this paper, we propose an efficient data mining algorithm named TMP-Mine with a special data structure named TMP-Tree for efficiently discovering the temporal movement patterns of objects in sensor networks. Moreover, we propose novel location prediction strategies that employ the discovered temporal movement patterns so as to reduce the prediction errors for energy saving. Through empirical evaluation on simulated, TMP-Mine and the proposed prediction strategies are shown to deliver excellent performance in terms of scalability, accuracy and energy efficiency.
Successfully detecting and correcting false friends using channel profiles
Authors: Ulrich Reffle, Annette Gotscharek, Christoph Ringlstetter, Klaus U. Schulz
Venue: Proceedings of the second workshop on Analytics for noisy unstructured text data (2008)

The detection and correction of false friends - also called real-word errors - is a notoriously difficult problem. On realistic data, the break-even point for automatic correction so far could not be reached: the number of additional infelicitous corrections outnumbered the useful corrections. We present a new approach where we first compute a profile of the error channel for the given text. During the correction process, the profile helps to restrict attention to a small set of "suspicious" lexical tokens of the input text where it is "plausible" to assume that the token represents a false friend. Using a conventional word trigram statistics for disambiguation we obtain a correction method that can be successfully applied to unrestricted text. In experiments for OCR documents, we show significant accuracy gains by fully automatic correction of false friends.