ppxscal/embedding_network huggingface dataset:
An application of optimal control theory to river pollution remediation
Authors: L. J. Alvarez-Vázquez, A. Martínez, M. E. Vázquez-Méndez, M. A. Vilar
Venue: Applied Numerical Mathematics (2009)

The main goal of this work is to use mathematical modelling and numerical optimization to obtain the optimal purification of a polluted section of a river. The most common strategy consists of the injection of clear water from a reservoir in a nearby point. In this process, the main problem consists, once the injection point is selected by geophysical reasons, of finding the minimum quantity of water which is needed to be injected into the river in order to purify it up to a fixed level: this will be the aim of this paper. We formulate this problem as a hyperbolic optimal control problem with control constraints, where the state system is given by the 1D shallow water equations coupled with the pollutant concentration equation, the control is the flux of injected water, and the objective function is related to the total quantity of injected water and the pollution thresholds. We present the mathematical formulation of the environmental problem, deriving a first order optimality condition in order to characterize the optimal solutions (via the introduction of the adjoint system for the computation of the gradient of the cost function). Finally, we deal with the numerical resolution of a realistic problem, where a finite element/finite difference discretization is used, an optimization algorithm is proposed, and computational results are provided.
A simulation study on the impact of physician starting time in a physical examination service
Authors: Wheyming T. Song, Aaron E. Bair, Mingchang Chih
Venue: Proceedings of the 40th Conference on Winter Simulation (2008)

The objective of our project was to improve the efficiency of a screening physical examination service of a large hospital system. We began with a detailed simulation model to explore the relationships between four performance measures and three decision factors. These included various dispatching rules, physician starting inquiry time, and scheduled patient arrival time. We then attempted to identify the optimal physician starting inquiry time. Our simulations show that (1) the three patient dispatching rules have negligible influence on any of the four outcome measures; (2) two types of patient arrival policies did not affect any of the four measures; (3) the proposed optimal physician starting inquiry time decreased patient wait time by 50% without increasing overall physician utilization. Based on these finding, we propose two improved policies. Policy 1 proposes changing the physician inquiry starting time from 10:30 am to 9:00 am. Policy 1 decreases patient wait time by 50% without increasing overall physician utilization and total physician shift time. Policy 2 suggests the postponement or removal of the physician inquiry stage but patients with abnormal results will be scheduled for further inspection.
Fingerprint Template Compression: A Graph-based Approach
Authors: Olivia Dietzel
Venue:  (2008)

Especially for verification purposes fingerprinttemplates become ever more important. Thereto inorder to recognize a person a reference template mustbe available, which can be stored for instance in adatabase or on a RFID chip. With regard to mobilestorage media, and thus only a small amount ofmemory, a need for compression arises. Such acompression can be lossy, possible errors in therecognition however, should be kept as small aspossible. In this book a new approach for thecompression of fingerprint templates is presented.Such templates contain information about thepositions and orientations of the so-called minutiae,which are in turn represented in the form ofd-dimensional points. So, the focus lies on the studyof graph-based approaches. The basic idea is to storethe difference vectors between always two pointsinstead of the minutiae. Since for this purposedirected spanning trees allow an efficient encoding,different approaches based on various spanning treesare studied and evaluated.
Context-sensitive static transistor-level IR analysis
Authors: Weiqing Guo, Yu Zhong, Tom Burd
Venue: Proceedings of the 2008 IEEE/ACM International Conference on Computer-Aided Design (2008)

With advances in semiconductor process technology, chip power density has dramatically increased, making power grid integrity a critical concern at all stages of the design process. Given the inherent difficulty of capturing worst-case IR drops for all logic gates with dynamic vectors, a static flow is essential for verifying grid integrity on complex chip designs, especially microprocessors. A novel static transistor-level IR drop analysis flow which significantly reduces the conservatism of other static flows is presented. The key feature of this flow is a fast NAND decision diagram (NDD) algorithm, a lightweight variant of a boolean decision diagram (BDD) with the capacity to effectively process device transition exclusions in a per logical-device, context-sensitive fashion, thereby radically reducing the conservatism typical of static analysis.
Polyadic Dynamic Logics for HPSG Parsing
Authors: Anders Søgaard, Martin Lange
Venue: Journal of Logic, Language and Information (2009)

Head-driven phrase structure grammar (HPSG) is one of the most prominent theories employed in deep parsing of natural language. Many linguistic theories are arguably best formalized in extensions of modal or dynamic logic (Keller, Feature logics, infinitary descriptions and grammar, 1993; Kracht, Linguistics Philos 18:401---458, 1995; Moss and Tiede, In: Blackburn, van Benthem, and Wolther (eds.) Handbook of modal logic, 2006), and HPSG seems to be no exception. Adequate extensions of dynamic logic have not been studied in detail, however; the most important aspect is the reference to sets of substructures. In this paper, an adequate extension is identified, and some important results are established: Satisfiability is highly undecidable, and model checking is shown to be in EXPTIME and PSPACE-hard. A fragment with polynomial time model checking procedures is identified; it is shown to cover considerable fragments of HPSG.
Expansions of multivariate Pickands densities and testing the tail dependence
Authors: Melanie Frick, Rolf-Dieter Reiss
Venue: Journal of Multivariate Analysis (2009)

Multivariate extreme value distribution functions (EVDs) with standard reverse exponential margins and the pertaining multivariate generalized Pareto distribution functions (GPDs) can be parametrized in terms of their Pickands dependence function D with D=1 representing tail independence. Otherwise, one has to deal with tail dependence. Besides GPDs we include in our statistical model certain distribution functions (dfs) which deviate from the GPDs whereby EVDs serve as special cases. Our aim is to test tail dependence against rates of tail independence based on the radial component. For that purpose we study expansions and introduce a second order condition for the density (called Pickands density) of the joint distribution of the angular and radial component with the Pickands densities under GPDs as leading terms. A uniformly most powerful test procedure is established based on asymptotic distributions of radial components. It is argued that there is no loss of information if the angular component is omitted in the testing problem.
Tracking transaction footprints for non-intrusive end-to-end monitoring
Authors: Bikram Sengupta, Nilanjan Banerjee, Chatschik Bisdikian, Paul Hurley
Venue: Cluster Computing (2009)

Existing transaction monitoring solutions are either platform-specific or rely on instrumentation techniques, which limit their applicability. Consequently, transaction monitoring in enterprise environments often involves the manual collation of information spread across a variety of infrastructure elements and applications, and is a time-consuming and labor-intensive task. To address this problem, we have developed an online, non-intrusive and platform-agnostic solution for transaction monitoring. The solution includes a transaction model discovery component that leverages historical system log files, containing transaction footprints and generates a model of the transaction in terms of valid sequence of steps that a transaction instance may execute and the expected footprint patterns at each step. The online monitoring system, in turn, takes in only (a) online system log files and (b) the transaction model, as inputs and generates a dynamic execution profile of ongoing transaction instances that allows their status to be tracked at individual and aggregate levels, even when transaction footprints do not necessarily carry correlating identifiers as those injected through instrumentation. In this paper, we describe the transaction model discovery and monitoring system including the architecture and algorithms, followed by results from an empirical study, ongoing work on run-time model validation and directions for future research.
A self-healing multipath routing protocol
Authors: Thomas Meyer, Lidia Yamamoto, Christian Tschudin
Venue: Proceedings of the 3rd International Conference on Bio-Inspired Models of Network, Information and Computing Sytems (2008)

This paper introduces a self-healing multipath routing solution that is resilient to code knock-out attacks i.e., the software copes with changing network topologies and perturbations of link characteristics as well as loss of parts of its code base. We use the Fraglets artificial chemistry for building a distributed reaction network that spans the whole network topology. Unlike the use of explicit metric values in today's network protocols, our approach relies on the concentration of routing table entries to stochastically decide which path a packet should take through the network. A reinforcement mechanism rewards successful forwarding rules that compete against each other for delivering data packets over alternative paths. Our self-healing solution is based on the systematic use of self-replicating code that constantly rewrites itself.
Key hierarchies for hierarchical access control in secure group communications
Authors: Junzhi Yan, Jianfeng Ma, Hongyue Liu
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2009)

The problem of hierarchical access control in secure group communications has elicited much interest in the literatures. However, most of the researches to date on hierarchical access control pay more attention to the particular encryption techniques, but considered little about the features of key hierarchies. In hierarchical access control systems, keys are usually organized hierarchically. We analyze the user-based, resource-based and unified key hierarchies in this paper. The first two hierarchies are established from the access matrix. By unifying these two hierarchies, we get the unified key hierarchy. Furthermore, we introduce the explicit accessible set and the explicit dominating set to describe the key distributions for these hierarchies, and prove that the unified key hierarchy can be formed from the explicit dominating sets in the user-based key hierarchy or the explicit accessible sets in the resource-based key hierarchy. To evaluate the efficiency of the described key hierarchies, we combine these hierarchies with the existing key assignment models and analyze their storage and rekey overheads. These overheads can be derived from the access matrix, and the derivation procedure is described. The conclusions of this paper can help to establish a suitable key hierarchy so as to make the key assignment scheme more efficient in practical applications.
Sheaves and Geometric Logic and Applications to Modular Verification of Complex Systems
Authors: Viorica Sofronie-Stokkermans
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

In this paper we show that states, transitions and behavior of concurrent systems can often be modeled as sheaves over a suitable topological space. In this context, geometric logic can be used to describe which local properties, of individual systems, are preserved, at a global level, when interconnecting the systems. The main area of application is to modular verification of complex systems. We illustrate the ideas by means of an example involving a family of interacting controllers for trains on a rail track.
Idempotent work stealing
Authors: Maged M. Michael, Martin T. Vechev, Vijay A. Saraswat
Venue: Proceedings of the 14th ACM SIGPLAN symposium on Principles and practice of parallel programming (2009)

Load balancing is a technique which allows efficient parallelization of irregular workloads, and a key component of many applications and parallelizing runtimes. Work-stealing is a popular technique for implementing load balancing, where each parallel thread maintains its own work set of items and occasionally steals items from the sets of other threads. The conventional semantics of work stealing guarantee that each inserted task is eventually extracted exactly once. However, correctness of a wide class of applications allows for relaxed semantics, because either: i) the application already explicitly checks that no work is repeated or ii) the application can tolerate repeated work. In this paper, we introduce idempotent work tealing, and present several new algorithms that exploit the relaxed semantics to deliver better performance. The semantics of the new algorithms guarantee that each inserted task is eventually extracted at least once-instead of exactly once. On mainstream processors, algorithms for conventional work stealing require special atomic instructions or store-load memory ordering fence instructions in the owner's critical path operations. In general, these instructions are substantially slower than regular memory access instructions. By exploiting the relaxed semantics, our algorithms avoid these instructions in the owner's operations. We evaluated our algorithms using common graph problems and micro-benchmarks and compared them to well-known conventional work stealing algorithms, the THE Cilk and Chase-Lev algorithms. We found that our best algorithm (with LIFO extraction) outperforms existing algorithms in nearly all cases, and often by significant margins.
A two-directional Arnoldi process and its application to parametric model order reduction
Authors: Yung-Ta Li, Zhaojun Bai, Yangfeng Su
Venue: Journal of Computational and Applied Mathematics (2009)

We consider a two-directional Krylov subspace K"k(A"["j"],b"["j"]), where besides the dimensionality k of the subspace increases, the matrix A"["j"] and vector b"["j"] which induce the subspace may also augment. Specifically, we consider the case where the matrix A"["j"] and the vector b"["j"] are augmented by block triangular bordering. We present a two-directional Arnoldi process to efficiently generate a sequence of orthonormal bases Q"k^[^j^] of the Krylov subspaces. The concept of a two-directional Krylov subspace and an Arnoldi process is triggered by the need of a multiparameter moment-matching based model order reduction technique for parameterized linear dynamical systems. Numerical examples illustrate computational efficiency and flexibility of the proposed two-directional Arnoldi process.
Domain-Specific Languages for Service-Oriented Architectures: An Explorative Study
Authors: Ernst Oberortner, Uwe Zdun, Schahram Dustdar
Venue: Proceedings of the 1st European Conference on Towards a Service-Based Internet (2008)

Domain-specific languages (DSLs) are an important software development approach for many service-oriented architectures (SOAs). They promise to model the various SOA concerns in a suitable way for the various technical and non-technical stakeholders of a SOA. However, so far the research on SOA DSLs concentrates on novel technical contributions, and not much evidence or counter-evidence for the claims associated to SOA DSLs has been provided. In this paper, we present a qualitative, explorative study that provides an initial analysis of a number of such claims through a series of three prototyping experiments in which each experiment has developed, analyzed, and compared a set of DSLs for process-driven SOAs. Our result is to provide initial evidence for a number of popular claims about SOA DSLs which follow the model-driven software development (MDSD) approach, as well as a list of design trade-offs to be considered in the design decisions that must be made when developing a SOA DSL.
Simulation framework for communication protocols of molecular communication systems
Authors: Frank Walsh, Sasitharan Balasubramaniam, Dmitri Botvich, Tadashi Nakano, Tatsuya Suda
Venue: Proceedings of the 3rd International Conference on Bio-Inspired Models of Network, Information and Computing Sytems (2008)

In this paper, we describe a protocol stack to enable communication between biological nano scale (bio-nano) devices. We identify key design considerations and protocol components and suggest suitable molecular computing mechanisms to create these components. Finally, we introduce a modeling and simulation framework for bio-nano communication networks.
An "Ethical" Game-Theoretic Solution Concept for Two-Player Perfect-Information Games
Authors: Joshua Letchford, Vincent Conitzer, Kamal Jain
Venue: Proceedings of the 4th International Workshop on Internet and Network Economics (2008)

The standard solution concept for perfect-information extensive form games is subgame perfect Nash equilibrium. However, humans do not always play according to a subgame perfect Nash equilibrium, especially in games where it is possible for all the players to obtain much higher payoffs if they place some trust in each other (and this trust is not violated). In this paper, we introduce a new solution concept for two-player perfect-information games that attempts to model this type of trusting behavior (together with the "ethical" behavior of not violating that trust). The concept takes subgame perfect equilibrium as a starting point, but then repeatedly resolves the game based on the players being able to trust each other. We give two distinct algorithmic definitions of the concept and show that they are equivalent. Finally, we give a fast implementation of one of the algorithms for solving the game, and show that it runs in time O(nlogn + nhlog(n/h)).
Direct Zero-Norm Optimization for Feature Selection
Authors: Kaizhu Huang, Irwin King, Michael R. Lyu
Venue: Proceedings of the 2008 Eighth IEEE International Conference on Data Mining (2008)

Zero-norm, defined as the number of non-zero elements in a vector, is an ideal quantity for feature selection. However, minimization of zero-norm is generally regarded as a combinatorially difficult optimization problem. In contrast to previous methods that usually optimize a surrogate of zero-norm, we propose a direct optimizationmethod to achieve zero-norm for feature selection in this paper. Based on Expectation Maximization (EM), this method boils down to solving a sequence of Quadratic Programming problems and hence can be practically optimized in polynomial time. We show that the proposed optimization technique has a nice Bayesian interpretation and converges to the true zero norm asymptotically, provided that agood starting point is given. Following the scheme of our proposed zero-norm, we even show that an arbitrary-norm based Support Vector Machine can be achieved in polynomial time. A series of experiments demonstrate that our proposed EM based zero-norm outperforms other state-of-the-art methods for feature selection on biological microarray data and UCI data, in terms of both the accuracy and the learning efficiency.
Original paper: Weed image classification using Gabor wavelet and gradient field distribution
Authors: Asnor Juraiza Ishak, Aini Hussain, Mohd Marzuki Mustafa
Venue: Computers and Electronics in Agriculture (2009)

This paper presents an image analysis technique that utilizes a combination of a Gabor wavelet (GW) and gradient field distribution (GFD) techniques to extract a new set of feature vectors based on their directional texture properties for the classification of weed types. The feature extraction process involves the use of GW to enhance the directional feature of the images, followed by GFD implementation to produce histogram gradient orientation angles and additional steps to generate the histogram envelope. Next, curve fitting technique is used to estimate the envelope function to determine its quadratic polynomial equation, y=ax2+bx+c and by taking the second derivative, the curvature value, a, is determined and used as a single input feature vector. The proposed technique was compared with another technique that also uses a single input feature obtained via GW algorithm implementation only. The overall classification accuracy utilizing the proposed technique is 94%, whereas using a GW only feature obtained 84% accuracy. The results obtained showed that this proposed technique is effective in performing weed classification.
Large Code Set for Double User Capacity and Low PAPR Level in Multicarrier Systems
Authors: Khoirul Anwar, Masato Saito, Takao Hara, Minoru Okada
Venue: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (2008)

In this paper, a new large spreading code set with a uniform low cross-correlation is proposed. The proposed code set is capable of (1) increasing the number of assigned user (capacity) in a multicarrier code division multiple access (MC-CDMA) system and (2) reducing the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system. In this paper, we derive a new code set and present an example to demonstrate performance improvements of OFDM and MC-CDMA systems. Our proposed code set with code length of N has K = 2N + 1 number of codes for supporting up to (2N + 1) users and exhibits lower cross correlation properties compared to the existing spreading code sets. Our results with subcarrier N = 16 confirm that the proposed code set outperforms the current pseudo-orthogonal carrier interferometry (POCI) code set with gain of 5 dB at bit-error-rate (BER) level of 10-4 in the additive white Gaussian noise (AWGN) channel and gain of more than 3.6 dB in a multipath fading channel.
A JND Guided Foveation Video Coding
Authors: Erli Zhang, Debin Zhao, Yongbing Zhang, Hongbin Liu, Siwei Ma, Ronggang Wang
Venue: Proceedings of the 9th Pacific Rim Conference on Multimedia: Advances in Multimedia Information Processing (2008)

This paper presents a novel just noticeable distortion (JND) guided foveation video coding method, by which the foveation region can be adaptively selected according to the video content. In the proposed method, two factors are taken into account: first, we set a fixed foveation and then get the cut-off frequency for every macroblock. Second, we compute the JND values for each pixel in the frame to be encoded, and then use the JND variance of each macroblock to tune the corresponding cut-off frequency. The method presented can be implemented without any modification of the decoder and is compatible with all the existed coding standards. Based on the proposed mode, a framework of preprocessing is brought forward. And experimental results have demonstrated that foveated pictures with higher perceptual quality could be obtained, compared with traditional foveation model.