ppxscal/embedding_network huggingface dataset:
Efficient placement of proxies for hierarchical reliable multicast
Authors: Liansheng Tan, Li Jin, Yi Pan
Venue: Computer Communications (2008)

The primary focus of this paper is the design of efficient algorithm for the calculation of solution to the placement of proxies for performance optimization in hierarchical reliable multicast (HRM). Proxy is introduced to localize feedback and retransmission, and therefore significantly depress traffic redundancy and reduce latency. Placement of proxies is a key issue in HRM. This paper theoretically analyzes the performance improvement made by placement of proxies and presents a new approach to optimal partition of a subtree for performance optimization in the placement of a single proxy. Based on this approach, we propose a new algorithm, designed in a greedy fashion. We experimentally compare our new algorithm with several existing heuristic algorithms, and observe that it outperforms in the tradeoff between performance and complexity.
Faster algorithms for the generalized network flow problem
Authors: T. Radzik
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We consider the generalized network flow problem. Each arc e in the network has a gain factor /spl gamma/(e). If f(e) units of flow enter arc e, then f(e)/spl gamma/(e) units arrive at the other end of e. The generalized network flow problem is to maximize the net flow into one specific node, the sink. We give an algorithm which solves this problem in O/spl tilde/(m/sup 2/(m+nloglog B)log B) time, where B is the largest integer used to represent the gain factors, the capacities, and the initial supplies at the nodes. If m is O(n/sup (4/3/-/spl epsiv/) and B is not extremely large, then our bound improves the previous best bound O(m/sup 1.5/n/sup 2/log B) given by P.M. Vaidya (1989). Our algorithm is an approximation scheme which in each iteration reduces by a constant factor the difference between the current net flow into the sink and the optimal one. The solution which is within a factor of 1+/spl xi/ from the optimum can be computed in O/spl tilde/(m/sup 2/n+min{m/sup 2/n, m(m+nloglog B)}log(1//spl xi/)) time. This improves the previous bounds on the approximate generalized flow problem.
Review: Sensor systems for measuring soil compaction: Review and analysis
Authors: A. Hemmat, V. I. Adamchuk
Venue: Computers and Electronics in Agriculture (2008)

Spatially variable soil compaction often causes inconsistent growing conditions in many fields. Various soil compaction sensor systems have been deployed to obtain georeferenced maps of certain state and behavioral properties (e.g., soil strength, water content, air permeability) related to compaction. This publication classifies different prototype sensors, and reviews alternative measurement concepts from the viewpoint of soil mechanics. The majority of discussion is dedicated to a diversified family of soil strength sensors developed around the world. Through the follow-up analysis, a concept of sensor fusion has been emphasized as an option capable of improving future applicability of soil compaction sensor systems, while implementing site-specific control of localized compaction occurrences.
Orchestrating data transfer for the cell/B.E. processor
Authors: Tong Chen, Haibo Lin, Tao Zhang
Venue: Proceedings of the 22nd annual international conference on Supercomputing (2008)

In heterogeneous multi-core systems, such as the Cell/B.E. or certain embedded systems, the accelerator core has its own fast local memory without hardware supported coherence between the local and global memories. It is software's responsibility to dynamically transfer the working set into the local memory when the total data set is too large to fit in the local memory. The data can be transferred through either a software controlled cache or a direct buffer. Such a software cache can maintain correctness and exploit reuse among references, especially when complicated aliasing or data dependences exist. However, the software cache introduces the extra overhead of cache lookup. Direct buffering, on the other hand, is fast but is limited by the compiler's ability to disambiguate memory references. It is desirable to judiciously use both methods, for irregular and regular accesses respectively. However, when a datum resides in both the software cache and the direct buffer, coherence problems occur. In this paper, we propose a solution which provides compile time analysis and runtime maintenance to address this coherence issue. We use compiler analysis to guarantee that there is no access to software cache within the local live range of a direct buffer, and rely on runtime support to update values from or to software cache at the entry or exit of the direct buffer. Further, we present a global data flow analysis design to eliminate redundant coherence maintenance, and overlap computation and DMA accesses to reduce runtime overhead. We have implemented this method in our Single Source Compiler for Cell, and have conducted experiments with the NAS OpenMP benchmarks. The results show that our method maintains correctness while keeping most of the opportunities for direct buffering. The execution performance can increase more than 3x compared to approaches using only the software cache. Furthermore, compile time analysis can reduce 90% of the runtime updates, thereby improving performance by 20% further.
A Hierarchical Compositional Model for Face Representation and Sketching
Authors: Zijian Xu, Hong Chen, Song-Chun Zhu, Jiebo Luo
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2008)

We present a hierarchical-compositional face model as a three-layer And-Or graph to account for the structural variabilities over multiple resolutions. In the And-Or graph, an And-node represents a decomposition of certain graphical structure expanding to a set of Or-nodes with associated relations; an Or-node functions as a switch variable pointing to alternative And-nodes. Faces are represented hierarchically: layer one treats each face as a whole; layer two refines the local facial parts jointly as a set of individual templates; layer three divides face into 15 zones and models facial features like eyecorners or wrinkles. Transitions between layers are realized by measuring the minimum-description-length given the face image complexity. Diverse face representations are formed by drawing from hierarchical dictionaries of faces, parts and skin features. A sketch captures the most informative part of a face in a concise and potentially robust representation. However, generating good facial sketches is challenging because of the rich facial details and large structural variations, especially in the high-resolution images. The representing power of our generative model is demostrated by reconstructing high-resolution face images and generating cartoon sketches. Our model is useful for applications such as face recognition, non-photorealisitc rendering, super-esolution, and low-bit rate face coding.
On fixed points of permutations
Authors: Persi Diaconis, Jason Fulman, Robert Guralnick
Venue: Journal of Algebraic Combinatorics: An International Journal (2008)

The number of fixed points of a random permutation of {1,2,¿,n} has a limiting Poisson distribution. We seek a generalization, looking at other actions of the symmetric group. Restricting attention to primitive actions, a complete classification of the limiting distributions is given. For most examples, they are trivial --- almost every permutation has no fixed points. For the usual action of the symmetric group on k-sets of {1,2,¿,n}, the limit is a polynomial in independent Poisson variables. This exhausts all cases. We obtain asymptotic estimates in some examples, and give a survey of related results.
Probabilistic communication complexity of Boolean relations
Authors: R. Raz, A. Wigderson
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

The authors demonstrate an exponential gap between deterministic and probabilistic complexity and between the probabilistic complexity of monotonic and nonmonotonic relations. They then prove, as their main result, an Omega ((log n)/sup 2/) bound on the probabilistic communication complexity of monotonic st-connectivity. From this they deduce that every nonmonotonic NC/sup 1/ circuit for st-connectivity requires a constant fraction of negated input variables.
SybilGuard: defending against sybil attacks via social networks
Authors: Haifeng Yu, Michael Kaminsky, Phillip B. Gibbons, Abraham D. Flaxman
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

Peer-to-peer and other decentralized, distributed systems are known to be particularly vulnerable to sybil attacks. In a sybil attack, a malicious user obtains multiple fake identities and pretends to be multiple, distinct nodes in the system. By controlling a large fraction of the nodes in the system, the malicious user is able to "out vote" the honest users in collaborative tasks such as Byzantine failure defenses. This paper presents SybilGuard, a novel protocol for limiting the corruptive influences of sybil attacks. Our protocol is based on the "social network" among user identities, where an edge between two identities indicates a human-established trust relationship. Malicious users can create many identities but few trust relationships. Thus, there is a disproportionately small "cut" in the graph between the sybil nodes and the honest nodes. SybilGuard exploits this property to bound the number of identities a malicious user can create. We show the effectiveness of SybilGuard both analytically and experimentally.
Parallel programming of multi-processor SoC: a HW-SW interface perspective
Authors: Lobna Kriaa, Aimen Bouchhima, Marius Gligor, Anne-Marie Fouillart, Fréderic Pétrot, Ahmed-Amine Jerraya
Venue: International Journal of Parallel Programming (2008)

For the design of classic computers the parallel programming concept is used to abstract HW/SW interfaces during high level specification of application software. The software is then adapted to existing multiprocessor platforms using a low level software layer that implements the programming model. Unlike classic computers, the design of heterogeneous MPSoC includes also building the processors and other kind of hardware components required to execute the software. In this case, the programming model hides both hard-ware and software refinements. This paper deals with parallel programming models to abstract both hardware and software interfaces in the case of heterogeneous MPSoC design. Different abstraction levels will be needed. For the long term, the use of higher level programming models will open new vistas for optimization and architecture exploration like CPU/RTOS tradeoffs.
A practical update criterion for SQP method
Authors: Tao-Wen Liu, Dong-Hui Li
Venue: Optimization Methods Software (2007)

Sequential quadratic programming (SQP) algorithms have proven to be efficient for solving nonlinearly constrained optimization problems under some conditions. In analysis of global convergence for SQP algorithms, it is usually assumed that the quasi-Newton matrices, approximating the Hessian of Lagrangian function, are uniformly positive definite. However, it is not known whether this condition is satisfied for quasi-Newton matrices. In this paper, we present a new update criterion for the quasi-Newton matrix and a new update method for the penalty parameter. We establish the global convergence result of a modifying SQP algorithm for equality constrained optimization problems without any assumption on quasi-Newton matrix sequence. Moreover, if the second-order sufficient condition holds at an optimal solution, the new update criterion reduces to the ordinary BFGS update. The superlinear rate of convergence of the algorithm can be obtained if an additional step is performed.
On Power Dissipation in Information Processing
Authors: Roman Ostroumov, Kang L. Wang
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

We consider power dissipation during simple switching in information processing. By considering general two-level system we show that the energy dissipation during errorless switching has a minimum of kTln2 and increases linearly with a switching speed. Also, we find optimal switching function, which minimizes heat dissipation for the given error rate. We present some estimates and compare them with results for the CMOS technology.
Tracking port scanners on the IP backbone
Authors: Avinash Sridharan, Tao Ye
Venue: Proceedings of the 2007 workshop on Large scale attack defense (2007)

Port scanning is the usual precursor to malicious attacks on today's Internet. Although many algorithms have been proposed for different aspects of the scan detection problem, their focused designed space is enterprise gateway level Intrusion Detection. Furthermore, we find few studies that track scanner behaviors over an extended period of time. Operating from a unique vantage point, the IP backbone, we put all the pieces together in designing and implementing a fast and accurate online port scan detection and tracking system. We introduce our flexible architecture, discuss trade-offs and design choices. Specifically, we go in depth to two design choices: the distinct counter data structure and the buffer size tuning. Our choice of a probabilistic counter is proved to have a low average error of 3.5%. The buffer size is derived using Lyapunov drift techniques on an equivalent queuing model. Our initial scanner tracking results show that the scanners' timing behavior follows a 90-10 curve. That is, 90% of scanners are active for a short time, with low scanning rates, while 10% are long term and fast scanners, with a few super-scanners lasting the entire duration of monitoring.
Process Variation Characterization and Modeling of Nanoparticle Interconnects for Foldable Electronics
Authors: Rasit Onur Topaloglu
Venue: Proceedings of the 9th international symposium on Quality Electronic Design (2008)

Designers require variational information for robust designs. Characterization of such information can be costly for thenovel nanoparticle interconnect process, which utilize nanoparticle silver solutions. To reduce characterization cost and initiate circuit level considerations for foldable electronics, we provide nanoparticle interconnect models. We use SEM measurements to characterize nanoparticle size distribution. We conduct field solver simulations over the proposed model to obtain physics-based process variation impact on a nanoparticle interconnect resistance. Such methodology can be helpful to aid designers for circuits based on novel transistors, such as organic TFTs on low cost foldable substrates.
M-Channel Multiple Description Coding with Two-Rate Predictive Coding and Staggered Quantization
Authors: Upul Samarawickrama, Jie Liang
Venue: Proceedings of the Data Compression Conference (2008)

This paper presents a new low complexity multiple description coding (MDC) method that can generate any number of descriptions. For correlated sources, a special DPCM encoder is used in each description, such that it carries higher rate information of a subset of the samples and lower rate information of the rest. The lower rate codings in different descriptions are designed to be mutually refinable using staggered scalar quantizers. The closed-form expression of the expected distortion is derived when an arbitrary subset of the descriptions are received. Experimental results on natural images using lapped transform show that the proposed method is competent with the state-of-the-art multiple description image coders.
AMOLED pixel driver circuits based on poly-Si TFTs: A comparison
Authors: Gaetano Palumbo, Melita Pennisi
Venue: Integration, the VLSI Journal (2008)

In this paper, four different driver circuits for an active matrix organic light-emitting diode (AMOLED) pixel based on thin film transistor (TFT) technology are analyzed and compared. In particular, the comparison analyzed accuracy, driving speed, power consumption and area occupied. Moreover, in order to allow array simulations, the RC equivalent models of the pixel were also derived. The results were achieved considering a QVGA display (320x240), a line frequency of 60Hz, and were verified by simulations with AIM-SPICE.
Finding errors in .net with feedback-directed random testing
Authors: Carlos Pacheco, Shuvendu K. Lahiri, Thomas Ball
Venue: Proceedings of the 2008 international symposium on Software testing and analysis (2008)

We present a case study in which a team of test engineers at Microsoft applied a feedback-directed random testing tool to a critical component of the .NET architecture. Due to its complexity and high reliability requirements, the component had already been tested by 40 test engineers over five years, using manual testing and many automated testing techniques. Nevertheless, the feedback-directed random testing tool found errors in the component that eluded previous testing, and did so two orders of magnitude faster than a typical test engineer (including time spent inspecting the results of the tool). The tool also led the test team to discover errors in other testing and analysis tools, and deficiencies in previous best-practice guidelines for manual testing. Finally, we identify challenges that random testing faces for continued effectiveness, including an observed decrease in the technique's error detection rate over time.
A polynomial-time algorithm for the perfect phylogeny problem when the number of character states is fixed
Authors: R. Agarwala
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We present a polynomial-time algorithm for determining whether a set of species, described by the characters they exhibit, has a perfect phylogeny, assuming the maximum number of possible states for a character is fixed. This solves a longstanding open problem. Our result should be contrasted with the proof by Steel and Bodlaender, Fellows, and Warnow that the perfect phylogeny problem is NP-complete in general.
A Case Study of Issues Related to Automotive E/E System Architecture Development
Authors: Peter Wallin, Jakob Axelsson
Venue: Proceedings of the 15th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (2008)

The use of electronics in vehicles is increasing quickly and the systems are becoming increasingly complex. This makes the engineering of these advanced computer-based systems more and more difficult. In particular, finding a good architecture is a prerequisite for successful design. In this study we investigate key issues related to real-world decisions regarding a car's electrical and electronic system architecture. To extract the key issues an exploratory case study was performed at a car manufacturer. We used semi- formal interviews complemented with a survey to validate the results. The contribution of this paper is twelve issues that reflect the situation at a car manufacturer. Also, possible actions to deal with these issues are provided.
Script: Simulations from Grid to Ubiquitous Computing
Authors: Yih-Jiun Lee, Kai-Wen Lien
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

Ubiquitous Computing has gained ground over the last five years. It focuses on devices being able to connect to the net at any time from any place. It includes the modern term distributed computing, which means accessing resources from any place. Several behaviours in modern distributed computing can be observed. For instance, a process in one place can send an object to other places; a process can request an object from a remote provider; a process can be moved from one place to another and then continue its execution; a message might travel through many intermediaries before its destination. Too many participants in one action might cause computational complications. It is better if the system structure can be at proved before the action really takes place. Therefore, Script is a modelling language designed for ''simulating" and ''verifying" distributed computing, grid computing and ubiquitous computing. Although Script is currently a modelling language, it will be provided with a transformation tool to move a Script-based model into a real environment. This tool is under development.
Towards a green electronic world: a collaborative approach
Authors: Jaswinder Ahuja
Venue: Proceeding of the 13th international symposium on Low power electronics and design (2008)

Increasing power density of complex SoC's have made low-power a topic of interest in the industry. Power considerations in portable and wireless consumer devices have become a key part of many product specifications. Even for wired devices and other industry segments in which battery power has not traditionally been an issue, considerations of packaging, reliability, and cooling costs brings power firmly to the forefront at smaller geometries. In particular, as designs migrate to sub-90nm process nodes, power management becomes a serious concern across the entire design and manufacturing chain. To help design teams, there is a need to adopt advanced power reduction techniques, where a complete low power solution is needed for the design, verification, and implementation of low-power chips. Since the challenge spans across the design chain, industry collaboration is an imperative.
A multilingual knowledge management system: A case study of FAO and WAICENT
Authors: Daniel E. O'Leary
Venue: Decision Support Systems (2008)

This paper provides a case study of a multilingual knowledge management system for a large organization. In so doing we elicit what it means for a system to be ''multilingual'' and how that changes some previous research on knowledge management. Some researchers have viewed multilingual as meaning a multilingual user interface. However, that is only a small part of the story. In this case we find multilingual also refers to a broad range of ''multilingual,'' including multilingual knowledge resources, multilingual feedback from users, multilingual search, multilingual ontologies and other concerns.
An Execution Framework for MARTE-Based Models
Authors: Chokri Mraidha, Yann Tanguy, Christophe Jouvray, François Terrier, Sébastien Gérard
Venue: Proceedings of the 13th IEEE International Conference on on Engineering of Complex Computer Systems (2008)

The UML is now the most widespread language for systems modeling. However, this language has been designed as a general purpose modeling language that may lack for modeling constructs for specific domain, as for the real-time embedded (RTE) domain. In order to fill this lack, OMG has standardized a UML extension, called MARTE. This UML profile consists of specific concepts defined to cope with the specific concerns of the RTE domain. Of course, MARTE provides support for enabling model driven engineering (MDE) of RTE systems. The MDE development paradigm makes the model the first class citizen of development processes. Models need then to be productive. To achieve this purpose, providing methodology enabling model to be executable is a real challenge. The goal of this paper is then to present, on the one hand a UML/MARTE based methodology for executable RTE systems modeling and on the other hand, a framework and its underlying model transformations required to execute UML models conforming to the MARTE standard.