ppxscal/embedding_network huggingface dataset:
Explaining inferences in Bayesian networks
Authors: Ghim-Eng Yap, Ah-Hwee Tan, Hwee-Hwa Pang
Venue: Applied Intelligence (2008)

While Bayesian network (BN) can achieve accurate predictions even with erroneous or incomplete evidence, explaining the inferences remains a challenge. Existing approaches fall short because they do not exploit variable interactions and cannot account for compensations during inferences. This paper proposes the Explaining BN Inferences (EBI) procedure for explaining how variables interact to reach conclusions. EBI explains the value of a target node in terms of the influential nodes in the target's Markov blanket under specific contexts, where the Markov nodes include the target's parents, children, and the children's other parents. Working back from the target node, EBI shows the derivation of each intermediate variable, and finally explains how missing and erroneous evidence values are compensated. We validated EBI on a variety of problem domains, including mushroom classification, water purification and web page recommendation. The experiments show that EBI generates high quality, concise and comprehensible explanations for BN inferences, in particular the underlying compensation mechanism that enables BN to outperform alternative prediction systems, such as decision tree.
Online maintenance of very large random samples on flash storage
Authors: Suman Nath, Phillip B. Gibbons
Venue: Proceedings of the VLDB Endowment (2008)

Recent advances in flash media have made it an attractive alternative for data storage in a wide spectrum of computing devices, such as embedded sensors, mobile phones, PDA's, laptops, and even servers. However, flash media has many unique characteristics that make existing data management/analytics algorithms designed for magnetic disks perform poorly with flash storage. For example, while random (page) reads are as fast as sequential reads, random (page) writes and in-place data updates are orders of magnitude slower than sequential writes. In this paper, we consider an important fundamental problem that would seem to be particularly challenging for flash storage: efficiently maintaining a very large (100 MBs or more) random sample of a data stream (e.g., of sensor readings). First, we show that previous algorithms such as reservoir sampling and geometric file are not readily adapted to flash. Second, we propose B-FILE, an energy-efficient abstraction for flash media to store self-expiring items, and show how a B-FILE can be used to efficiently maintain a large sample in flash. Our solution is simple, has a small (RAM) memory footprint, and is designed to cope with flash constraints in order to reduce latency and energy consumption. Third, we provide techniques to maintain biased samples with a B-FILE and to query the large sample stored in a B-FILE for a subsample of an arbitrary size. Finally, we present an evaluation with flash media that shows our techniques are several orders of magnitude faster and more energy-efficient than (flash-friendly versions of) reservoir sampling and geometric file. A key finding of our study, of potential use to many flash algorithms beyond sampling, is that "semi-random" writes (as defined in the paper) on flash cards are over two orders of magnitude faster and more energy-efficient than random writes.
Authenticating the query results of text search engines
Authors: HweeHwa Pang, Kyriakos Mouratidis
Venue: Proceedings of the VLDB Endowment (2008)

The number of successful attacks on the Internet shows that it is very difficult to guarantee the security of online search engines. A breached server that is not detected in time may return incorrect results to the users. To prevent that, we introduce a methodology for generating an integrity proof for each search result. Our solution is targeted at search engines that perform similarity-based document retrieval, and utilize an inverted list implementation (as most search engines do). We formulate the properties that define a correct result, map the task of processing a text search query to adaptations of existing threshold-based algorithms, and devise an authentication scheme for checking the validity of a result. Finally, we confirm the efficiency and practicality of our solution through an empirical evaluation with real documents and benchmark queries.
Anima: a Ada derived programming language for real-time embedded software development
Authors: Steven Doran
Venue: Proceedings of the 2008 ACM annual international conference on SIGAda annual international conference (2008)

Currently, embedded programs are written in a variety of programming languages. None were specifically designed for the real-time environment. The use of a general purpose language for embedded systems can lead to inefficient applications which are more likely to fail to meet timing and execution requirements, or experience run-time errors that prove catastrophic for safety-critical systems. A domain specific language, in which real-time constructs are part of the language proper rather than hosted in a library, is likely to lessen the risks of implementation of tasks with strict real-time requirements. This paper outlines a Ada derived programming language called Anima that directly addresses many of the challenging issues of real-time embedded software development.
Function approximation based augmented backstepping control for an induction machine
Authors: Mohammed Belkheiri, Fares Boudjema
Venue: WSEAS Transactions on Systems and Control (2007)

A new control approach is proposed to address the tracking problem of an induction machine based on a modified field-oriented control (FOC) method. In this approach, one relies first on a partially known model to the system to be controlled using a backstepping control strategy. The obtained controller is then augmented by an online neural network that serves as an approximator for the neglected dynamics and modeling errors. The proposed approach is systematic, and exploits the known nonlinear dynamics to derive the stepwise virtual stabilizing control laws. At the final step, an augmented Lyapunov function is introduced to derive the adaptation laws of the network weights. The effectiveness of the proposed controller is demonstrated through computer simulation.
A perfect QoS routing algorithm for finding the best path for dynamic networks
Authors: Hazem M. El-Bakry, Nikos Mastorakis
Venue: WSEAS TRANSACTIONS on COMMUNICATIONS (2008)

It is highly desirable to protect data traffic from unexpected changes as well as provide effective network utilization in the internetworking era. In this paper the QoS management issue that utilizing the active network technology is discussed. Such algorithm is based on the proposed work presented in [15]. Active networks seem to be particularly useful in the context of QoS support. The Active QoS Routing (AQR) algorithm which is based on On-demand routing is implemented incorporating the product of available bit rate and delay for finding the best path for dynamic networks using the active network test bed ANTS. It is inferred that with background traffic, the AQR finds alternative paths very quickly and the delay and subsequently the jitter involved are reduced significantly. In this paper the variant of AQR implemented is demonstrated to be more useful in reducing the jitter when the overall traffic in the network is heavy and has useful application in finding effective QoS routing in ad-hoc networks as well as defending DDoS attacks by identifying the attack traffic path using QoS regulations. The main achievement of this paper is the fast attack detection algorithm. Such algorithm based on performing cross correlation in the frequency domain between data traffic and the input weights of fast time delay neural networks (FTDNNs). It is proved mathematically and practically that the number of computation steps required for the presented FTDNNs is less than that needed by conventional time delay neural networks (CTDNNs). Simulation results using MATLAB confirm the theoretical computations.
Automatically locating framework extension examples
Authors: Barthélémy Dagenais, Harold Ossher
Venue: Proceedings of the 16th ACM SIGSOFT International Symposium on Foundations of software engineering (2008)

Using and extending a framework is a challenging task whose difficulty is exacerbated by the poor documentation that generally comes with the framework. Even in the presence of documentation, developers often desire implementation examples for concrete guidance. We propose an approach that automatically locates implementation examples from a code base given lightweight documentation of a framework. Based on our experience with concern-oriented documentation, we devised an approach that uses the framework documentation as a template and that finds instances of this template in a code base. The concern instances represent self-contained and structured implementation examples: the relationships and the roles of parts composing the examples are uncovered and explained. We implemented our approach in a tool and conducted a study comparing the results of our tool with results provided by Eclipse committers, showing that our approach can locate examples with high precision.
Segmentation and Tracking for Vision Based Human Robot Interaction
Authors: Salman Valibeik, Guang-Zhong Yang
Venue: Proceedings of the 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Volume 03 (2008)

Vision based Human Robot Interaction (HRI) in a crowded scene is a challenging research problem. The aim of this paper is to provide a reliable framework for simple gesture recognition for robotic navigation under partial occlusion and varying illumination conditions. The proposed method combines hand motion segmentation and skin colour detection for gesture recognition. Motion clustering based on Least Median Square Error (LMedS) followed by Kalman filtering and HMM gesture detection has been used. Experimental results have shown that the method can successfully restore the motion field that allows accurate, dominant affine motion detection for consistent gesture estimation.
Globally convergent Jacobian smoothing inexact Newton methods for NCP
Authors: Nataša Krejić, Sanja Rapajić
Venue: Computational Optimization and Applications (2008)

A new smoothing algorithm for the solution of nonlinear complementarity problems (NCP) is introduced in this paper. It is based on semismooth equation reformulation of NCP by Fischer---Burmeister function and its related smooth approximation. In each iteration the corresponding linear system is solved only approximately. Since inexact directions are not necessarily descent, a nonmonotone technique is used for globalization procedure. Numerical results are also presented.
Achieving 100% throughput in TCP/AQM under aggressive packet marking with small buffer
Authors: Do Young Eun, Xinbing Wang
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

We consider a TCP/AQM system with large link capacity (NC) shared by many flows. The traditional rule-of-thumb suggests that the buffer size be chosen in proportion to the number of flows (N) for full link utilization, while recent research outcomes show that O(√N) buffer sizing is sufficient for high utilization and O(1) buffer sizing makes the system stable at the cost of reduced link utilization. In this paper, we consider a system where the Active Queue Management (AQM) is scaled as O(Nα) with a buffer of size O(Nβ) (0 < α < β < 0.5). By capturing randomness both in packet arrivals and in packet markings, we develop a doubly-stochastic model for a TCP/AQM system with many flows. We prove that, under such a scale, the system always performs well in the sense that the link utilization goes to 100% and the loss ratio decreases to zero as the system size N increases. Our results assert that the system enjoys benefit of largeness with no tradeoff between full link utilization, zero packet loss, and small buffer size, at least asymptotically. This is in stark contrast to existing results showing that there always exists a tradeoff between full link utilization and the required buffer size. Extensive ns-2 simulation results under various configurations also confirm our theoretical findings. Our study illustrates that blind application of fluid modeling may result in strange results and exemplifies the importance of choosing a right modeling approach for different scaling regimes.
Improving supervised learning performance by using fuzzy clustering method to select training data
Authors: Donghai Guan, Weiwei Yuan, Young-Koo Lee, Andrey Gavrilov, Sungyoung Lee
Venue: Journal of Intelligent Fuzzy Systems: Applications in Engineering and Technology (2008)

The crucial issue in many classification applications is how to achieve the best possible classifier with a limited number of labeled data for training. Training data selection is one method which addresses this issue by selecting the most informative data for training. In this work, we propose three data selection mechanisms based on fuzzy clustering method: center-based selection, border-based selection and hybrid selection. Center-based selection selects the samples with high degree of membership in each cluster as training data. Border-based selection selects the samples around the border between clusters. Hybrid selection is the combination of center-based selection and border-based selection. Compared with existing work, our methods do not require much computational effort. Moreover, they are independent with respect to the supervised learning algorithms and initial labeled data. We use fuzzy c-means to implement our data selection mechanisms. The effects of them are empirically studied on a set of UCI data sets. Experimental results indicate that, compared with random selection, hybrid selection can effectively enhance the learning performance in all the data sets, center-based selection shows better performance in certain data sets, border-based selection does not show significant improvement.
Towards a Calculus for Collection-Oriented Scientific Workflows with Side Effects
Authors: Jan Hidders, Jacek Sroka
Venue: Proceedings of the OTM 2008 Confederated International Conferences, CoopIS, DOA, GADA, IS, and ODBASE 2008. Part I on On the Move to Meaningful Internet Systems: (2008)

In this paper we propose a calculus that can be used to describe the semantics of collection-oriented scientific workflow systems such as the Taverna workbench. Typically such systems focus on the specification and execution of workflows with a relatively simple control flow and a more complex data flow that involves large nested collections of data. An essential operation in such workflows is the instantiation of a certain nested workflow for each element of a collection. We argue that if such workflows call external services, their semantics must be described not only in terms of input-output behavior but also take side effects into account. Based on this assumption a trace semantics is defined that corresponds to the observational equivalence of two workflow specifications. We show that under such a semantics a relatively small calculus with a structural semantics can be defined and used to describe such workflows. This is demonstrated by giving a translation of Taverna workflows in terms of this calculus.
Revamping the IEEE 802.11a PHY simulation models
Authors: Jiho Ryu, Jeongkeun Lee, Sung-Ju Lee, Taekyoung Kwon
Venue: Proceedings of the 11th international symposium on Modeling, analysis and simulation of wireless and mobile systems (2008)

In simulating wireless networks, modeling of the physical layer behavior is an important yet difficult task. Modeling and estimating wireless interference is receiving great research attention, and is crucial in a wireless network performance study. The implementation of physical layer capture, preamble detection, and carrier sense threshold plays an important role in successful frame reception in the presence of interference. We showed in our previous testbed study that the operations of the frame reception and the capture effect in real IEEE 802.11a systems differ from those of popular research simulators. We present our modifications of the IEEE 802.11a PHY models to the current simulators. The modifications can be summarized as follows. (i) The current simulators' frame reception is based only on the received signal strength. However, the real 802.11 systems can start the frame reception only when the Signal-to-Interference Ratio (SIR) is high enough to detect the preamble. (ii) Different chipset vendors implement the frame reception and capture algorithms differently, resulting in different operations for the same event. We provide different simulation models for several popular chipset vendors and show the performance differences between the models. (iii) The current simulators set the carrier sense threshold equal to the receiver sensitivity. The standard however states that it should be 20 dB higher than the receiver sensitivity. We implement our modifications to the QualNet simulator and conduct a wireless network performance study to evaluate the impact of PHY model implementation.
Structural signatures for tree data structures
Authors: Ashish Kundu, Elisa Bertino
Venue: Proceedings of the VLDB Endowment (2008)

Data sharing with multiple parties over a third-party distribution framework requires that both data integrity and confidentiality be assured. One of the most widely used data organization structures is the tree structure. When such structures encode sensitive information (such as in XML documents), it is crucial that integrity and confidentiality be assured not only for the content, but also for the structure. Digital signature schemes are commonly used to authenticate the integrity of the data. The most widely used such technique for tree structures is the Merkle hash technique, which however is known to be "not hiding", thus leading to unauthorized leakage of information. Most techniques in the literature are based on the Merkle hash technique and thus suffer from the problem of unauthorized information leakages. Assurance of integrity and confidentiality (no leakages) of tree-structured data is an important problem in the context of secure data publishing and content distribution systems. In this paper, we propose a signature scheme for tree structures, which assures both confidentiality and integrity and is also efficient, especially in third-party distribution environments. Our integrity assurance technique, which we refer to as the "Structural signature scheme", is based on the structure of the tree as defined by tree traversals (pre-order, post-order, in-order) and is defined using a randomized notion of such traversal numbers. In addition to formally defining the technique, we prove that it protects against violations of content and structural integrity and information leakages. We also show through complexity and performance analysis that the structural signature scheme is efficient; with respect to the Merkle hash technique, it incurs comparable cost for signing the trees and incurs lower cost for user-side integrity verification.
PIGS
Authors: Paolo Marcatili, Alessandra Rosi, Anna Tramontano
Venue: Bioinformatics (2008)

Summary: We describe a web server for the automatic prediction of immunoglobulin variable domains based on the canonical structure model. The server is user-friendly and flexible. It allows the user to select the templates for the frameworks and the loops using different strategies. The final output is a full-fledged 3D model of the variable domains of the target immunoglobulin. Availability: The server is openly accessible to academic users at the address: http://arianna.bio.uniroma1.it/pigs. It does not require registration and there is no limit to the number of sequences that can be submitted. Contact: anna.tramontano@uniroma1.it
The application of remote sensing techniques to sugarcane (Saccharum spp. hybrid) production: a review of the literature
Authors: E. M. Abdel-Rahman, F. B. Ahmed
Venue: International Journal of Remote Sensing (2008)

Remote sensing techniques provide timely, up-to-date and relatively accurate information for the management of sugarcane crop. This article reviews the literature on the application of remote sensing to sugarcane agriculture and highlights the challenges and opportunities pertinent to the success of this application. The aim of the review was to provide accurate and fundamental information relating the spectral properties of sugarcane to its agronomic, health and nutritional status characteristics that would be of importance to cane farmers and farm managers. The applications of the remote sensing techniques in sugarcane agriculture have been undertaken with particular emphasis on sugarcane classification and areal extent mapping, thermal age group identification, varietal discrimination, yield prediction and crop health and nutritional status monitoring. It can be concluded that by selecting appropriate spatial and spectral resolution as well as suitable processing techniques for extracting sugarcane spectral information, remotely sensed data should find use in sugarcane agriculture in all areas of application with satisfactory results.
Fine-grained energy profiling for power-aware application design
Authors: Aman Kansal, Feng Zhao
Venue: ACM SIGMETRICS Performance Evaluation Review (2008)

Significant opportunities for power optimization exist at application design stage and are not yet fully exploited by system and application designers. We describe the challenges developers face in optimizing software for energy efficiency by exploiting application-level knowledge. To address these challenges, we propose the development of automated tools that profile the energy usage of various resource components used by an application and guide the design choices accordingly. We use a preliminary version of a tool we have developed to demonstrate how automated energy profiling helps a developer choose between alternative designs in the energy-performance trade-off space.
Towards realistic file-system benchmarks with CodeMRI
Authors: Nitin Agrawal, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Venue: ACM SIGMETRICS Performance Evaluation Review (2008)

Benchmarks are crucial to understanding software systems and assessing their performance. In file-system research, synthetic benchmarks are accepted and widely used as substitutes for more realistic and complex workloads. However, synthetic benchmarks are largely based on the benchmark writer's interpretation of the real workload, and how it exercises the system API. This is insufficient since even a simple operation through the API may end up exercising the file system in very different ways due to effects of features such as caching and prefetching. In this paper, we describe our first steps in creating "realistic synthetic" benchmarks by building a tool, CodeMRI. CodeMRI leverages file-system domain knowledge and a small amount of system profiling in order to better understand how the benchmark is stressing the system and to deconstruct its workload.