ppxscal/embedding_network huggingface dataset:
Spatial pattern analysis of land cover change trajectories in Tarim Basin, northwest China
Authors: Qiming Zhou, Baolin Li, Alishir Kurban
Venue: International Journal of Remote Sensing (2008)

This study attempts to develop a methodology to quantify spatial patterns of land cover change using landscape metrics. First, multitemporal land cover types are derived based on a unified land cover classification scheme and from the classification of multitemporal remotely sensed imagery. Categorical land cover change trajectories are then established and reclassified according to the nature and driving forces of the change. Finally, spatial pattern metrics of the land cover change trajectory classes are computed and their relationships to human activities and environmental factors are analysed. A case study in the middle reach of Tarim River in the arid zone of China from 1973 to 2000 shows that during the 30-year study period, the natural force is dominant in environmental change, although the human impact through altering water resources and surface materials has increased dramatically in recent years. The human-induced change trajectories generally show lower normalized landscape shape index (NLSI), interspersion and juxtaposition index (IJI) and area-weighted mean patch fractal dimension (FARC_AM), indicating greater aggregation, less association with others and simpler and larger patches in shape, respectively. The results suggest that spatial pattern metrics of land cover change trajectories can provide a good quantitative measurement for better understanding of the spatio-temporal pattern of land cover change due to different causes.
A cooperative control model for multiagent-based material handling systems
Authors: Henry Y. K. Lau, Vicky W. K. Wong, Alex K. S. Ng
Venue: Expert Systems with Applications: An International Journal (2009)

This paper presents an Artificial Immune System (AIS)-based model for cooperative control of multiagent systems. This cooperative control model describes collective behaviors of autonomous agents, known as the AIS agents that are exemplified by the regulated activities performed by individual agents under the computation paradigm of Artificial Immune System. The regulations and emergence of agent behaviors are derived from the immune threshold measures that determine those activities performed by the AIS agents at an individual level. These threshold measures together with the collective behavioral model defined the cooperative control of the AIS-based control framework under which AIS agents behave and act strategically according to the changing environment. The cooperative control model is presented under the three domains, namely exploration, achievement and cooperation domains where AIS agents operate. In this research, we implemented the proposed cooperative control model with a case study of automated material handling with a group of AIS agents that cooperate to achieve the defined tasks.
Empirical profile mixture models for phylogenetic reconstruction
Authors: Le Si Quang, Olivier Gascuel, Nicolas Lartillot
Venue: Bioinformatics (2008)

Motivation: Previous studies have shown that accounting for site-specific amino acid replacement patterns using mixtures of stationary probability profiles offers a promising approach for improving the robustness of phylogenetic reconstructions in the presence of saturation. However, such profile mixture models were introduced only in a Bayesian context, and are not yet available in a maximum likelihood (ML) framework. In addition, these mixture models only perform well on large alignments, from which they can reliably learn the shapes of profiles, and their associated weights. Results: In this work, we introduce an expectation–maximization algorithm for estimating amino acid profile mixtures from alignment databases. We apply it, learning on the HSSP database, and observe that a set of 20 profiles is enough to provide a better statistical fit than currently available empirical matrices (WAG, JTT), in particular on saturated data. Availability: We have implemented these models into two currently available Bayesian and ML phylogenetic reconstruction programs. The two implementations, PhyloBayes, and PhyML, are freely available on our web site ( http://atgc.lirmm.fr/cat). They run under Linux and MaxOSX operating systems. Contact: nicolas.lartillot@lirmm.fr Supplementary information:Supplementary data are available at Bioinformatics online.
A hierarchical evolutionary algorithm for automatic medical image segmentation
Authors: Chih-Chin Lai, Chuan-Yu Chang
Venue: Expert Systems with Applications: An International Journal (2009)

Image segmentation denotes a process of partitioning an image into distinct regions. A large variety of different segmentation approaches for images have been developed. Among them, the clustering methods have been extensively investigated and used. In this paper, a clustering based approach using a hierarchical evolutionary algorithm (HEA) is proposed for medical image segmentation. The HEA can be viewed as a variant of conventional genetic algorithms. By means of a hierarchical structure in the chromosome, the proposed approach can automatically classify the image into appropriate classes and avoid the difficulty of searching for the proper number of classes. The experimental results indicate that the proposed approach can produce more continuous and smoother segmentation results in comparison with four existing methods, competitive Hopfield neural networks (CHNN), dynamic thresholding, k-means, and fuzzy c-means methods.
A Game-Theoretic Approach to Determining Efficient Patrolling Strategies for Mobile Robots
Authors: Francesco Amigoni, Nicola Gatti, Antonio Ippedico
Venue: Proceedings of the 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Volume 02 (2008)

Use of game-theoretic models to address patrolling applications has gained increasing interest in the very last years. The patrolling agent is considered playing a game against an hostile possible intruder. In this paper, we adopt a game-theoretic approach for finding an efficient strategy for a patrolling mobile robot.
Characterization of failures in an operational IP backbone network
Authors: Athina Markopoulou, Gianluca Iannaccone, Supratik Bhattacharyya, Chen-Nee Chuah, Yashar Ganjali, Christophe Diot
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

As the Internet evolves into a ubiquitous communication infrastructure and supports increasingly important services, its dependability in the presence of various failures becomes critical. In this paper, we analyze IS-IS routing updates fromthe Sprint IP backbone network to characterize failures that affect IP connectivity. Failures are first classified based on patterns observed at the IP-layer; in some cases, it is possible to further infer their probable causes, such as maintenance activities, router-related and optical layer problems. Key temporal and spatial characteristics of each class are analyzed and, when appropriate, parameterized using well-known distributions. Our results indicate that 20% of all failures happen during a period of scheduled maintenance activities. Of the unplanned failures, almost 30% are shared by multiple links and are most likely due to router-related and optical equipment-related problems, respectively, while 70% affect a single link at a time. Our classification of failures reveals the nature and extent of failures in the Sprint IP backbone. Furthermore, our characterization of the different classes provides a probabilistic failure model, which can be used to generate realistic failure scenarios, as input to various network design and traffic engineering problems.
Distributed BIT diagnostic network Microsystems for miniature mobile robot
Authors: Yu Xiuli, Lou Wenzhong, Liu Xiaosong, Ma Baozheng, Wang Yongqiang
Venue: Microsystem Technologies (2008)

A perfect detecting method is a key factor for robotic systems, and the Built-in-Test (BIT) is the most important technological approach to improve the testability and diagnostic capability of robotic systems. The Miniature Wheel-Track-Legged Mobile Robot is studied, a distributed diagnostic network is presented based on Microsystems, BP network is applied and integrated with D-S evidence theory organically to deal with uncertain information. The robot can work in harsh environment, and has multimode moving methods, finally, an illustrative example of robot faults diagnosis proves that the BIT detecting system can obtain more status message through good structure, hiberarchy and module designing. Furthermore the system can get the information exactly and locate the faults properly, then isolate them. The self-diagnostic capability of robot can meet the need of the increasing reliability.
Randomized active atomicity violation detection in concurrent programs
Authors: Chang-Seo Park, Koushik Sen
Venue: Proceedings of the 16th ACM SIGSOFT International Symposium on Foundations of software engineering (2008)

Atomicity is an important specification that enables programmers to understand atomic blocks of code in a multi-threaded program as if they are sequential. This significantly simplifies the programmer's job to reason about correctness. Several modern multithreaded programming languages provide no built-in support to ensure atomicity; instead they rely on the fact that programmers would use locks properly in order to guarantee that atomic code blocks are indeed atomic. However, improper use of locks can sometimes fail to ensure atomicity. Therefore, we need tools that can check atomicity properties of lock-based code automatically. We propose a randomized dynamic analysis technique to detect a special, but important, class of atomicity violations that are often found in real-world programs. Specifically, our technique modifies the existing Java thread scheduler behavior to create atomicity violations with high probability. Our approach has several advantages over existing dynamic analysis tools. First, we can create a real atomicity violation and see if an exception can be thrown. Second, we can replay an atomicity violating execution by simply using the same seed for random number generation---we do not need to record the execution. Third, we give no false warnings unlike existing dynamic atomicity checking techniques. We have implemented the technique in a prototype tool for Java and have experimented on a number of large multi-threaded Java programs and libraries. We report a number of previously known and unknown bugs and atomicity violations in these Java programs.
A Low Complexity Reconfigurable DCT Architecture to Trade off Image Quality for Power Consumption
Authors: Jongsun Park, Kaushik Roy
Venue: Journal of Signal Processing Systems (2008)

In this paper we present a low complexity discrete cosine transform (DCT) architecture based on computation re-use in vector-scalar product. 1-D DCT operation is expressed as additions of vector-scalar products and basic common computations are identified and shared to reduce computational complexity in 1-D DCT operation. Compared to general distributed arithmetic based DCT architecture, the proposed DCT shows 38% of area and 18% of power savings with little performance degradation. We also propose an efficient method to trade off image quality for computational complexity. The approach is based on the modification of DCT bases in bit-wise manner and different computational complexity/image quality trade-off levels are suggested. Finally, based on the above approaches, we propose a low complexity DCT architecture, which can dynamically reconfigure from one trade-off level to another. The reconfigurable DCT architecture can achieve power savings ranging from 28% to 56% for 3 different trade-off levels.
Exploring the applicability of gradient elasticity to certain micro/nano reliability problems
Authors: Elias C. Aifantis
Venue: Microsystem Technologies (2008)

It has long been assessed that continuum mechanics can be used successfully to address a variety of mechanical problems at both macroscopic and microscopic scales. The term &#x201c;micromechanics&#x201d;, in particular, has been used in considering elasticity, plasticity, damage, and fracture mechanics problems at the micron scale involving metallic, ceramic and polymeric materials, as well as their composites. Applications to automobile, aerospace, and concrete industries, as well as to chemical and microelectronic technologies have already been documented. The recent developments in the field of nanotechnology have prompted a substantial literature in nanomechanics. While this term was first introduced by the author in the early 90&#x2019;s to advance a generalized continuum mechanics framework for applications at the nanoscale, it is mainly used today in considering &#x201c;hybrid&#x201d; ab-initio/molecular dynamics/finite element simulations, usually based on elasticity theory, to interpret the mechanical response of nano-objects (nanotubes, nanowires, nanoaggregates) and extract information on nano-configurations (dislocation cores, crack tips, interfaces). The modest goal of this article is to show that continuum elasticity can indeed be extended to describe a variety of problems at the micro/nano regime. The resultant micro/nanoelasticity theory includes long-range or nonlocal material point interactions and surface effects in the form of (phenomenological) higher-order stress/strain gradients. Coupled thermo-diffuso-chemo-mechanical processes can also be considered within such a higher-order theory. Size effects on micro/nano holes and micro/nano cracks can conveniently be modeled, and some standard strength of materials formulas routinely used for micro/nano beams can be improved, with potential applications to MEMS/NEMS devices and micro/nano reliability components.
Learning flow of control: recursive and iterative procedures
Authors: Claudius M. Kessler, John R. Anderson
Venue: Human-computer interaction (1986)

Two experiments were performed to study students' ability to write recursive and iterative programs and transfer between these two skills. Subjects wrote functions to accumulate instances into a list. Problems varied in terms of whether they were recursive or iterative, whether they operated on lists or numbers, whether they accumulated results in forward or backward manner, whether they accumulated on success or failure, and whether they simply skipped or ejected on failure to accumulate. Subjects had real difficulty only with the dimensions concerned with flow of control, namely, recursive versus iterative, and skip versus eject. We found positive transfer from writing iterative functions to writing recursive functions, but not vice versa. A subsequent protocol study revealed subjects had such a poor mental model of recursion that they developed poor learning strategies which hindered their understanding of iteration. It is argued that having an adequate model of the functionality of programming is prerequisite to learning to program, and that it is sensible pedagogical practice to base understanding of recursive flow of control on understanding iterative flow of control.
Ontology-Based Business Activity Monitoring Agent
Authors: Duco N. Ferro, Mark Hoogendoorn, Catholijn M. Jonker
Venue: Proceedings of the 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Volume 02 (2008)

Business Activity Monitoring (BAM) and Business Intelligence (BI) solutions are both intended to provide insight into the activities and performance of the enterprise. Deployment of such systems requires extensive tailoring to the enterprise, best left to experts. The dynamics of the enterprise demands a solution to the maintenance of BAM/BI solutions. This paper presents an Ontology-based BAM-Agent, called OBAMA that supports the maintenance of the system in light of changing business processes. Furthermore, for the formulation of aspects and properties to be monitored, it combines the expressive power of SQL, and TTL (a temporal trace language of first order logic). OBAMA helps in the preparation of regular assessment reports on the enterprise, taking into account key performance indicators as set by its operation manager. The paper describes the architecture, the combination of SQL, and TTL techniques for monitoring, and provides description of its kernel processes. OBAMA’s performance in a surveillance company is presented.
A questionnaire-based study on delayed reciprocity in a P2P-tv system
Authors: Jenneke E. Fokker, Piet H. Westendorp, Johan A. Pouwelse, Huib de Ridder
Venue: Proceeding of the 1st international conference on Designing interactive user experiences for TV and video (2008)

Using peer-to-peer (P2P) technology for distributing video files to many viewers simultaneously can only be successful if users cooperate voluntarily and massively. The current BitTorrent protocol enforces instantaneous bandwidth exchange within the context of one video file. To better exploit available resources for P2P-TV systems, such as our Tribler (www.tribler.org) software, we explore ways to induce user cooperation flexible over time and resources. The research is based on the social exchange theory and is done in two steps. First, the impact of social distance expressed in the degrees of separation (DoS) on the trust in reciprocity is investigated. Second, the DoS are combined with the kind of exchangeable resources typical for P2P-TV systems (i.e. injections and bandwidth) to find the influence of these variables on the accepted delay in reciprocity. The discussion will focus on the relation between trust in reciprocity and the accepted delay in reciprocity.
Predicting pathway membership via domain signatures
Authors: Holger Fröhlich, Mark Fellmann, Holger Sültmann, Annemarie Poustka, Tim Beißbarth
Venue: Bioinformatics (2008)

Motivation: Functional characterization of genes is of great importance for the understanding of complex cellular processes. Valuable information for this purpose can be obtained from pathway databases, like KEGG. However, only a small fraction of genes is annotated with pathway information up to now. In contrast, information on contained protein domains can be obtained for a significantly higher number of genes, e.g. from the InterPro database. Results: We present a classification model, which for a specific gene of interest can predict the mapping to a KEGG pathway, based on its domain signature. The classifier makes explicit use of the hierarchical organization of pathways in the KEGG database. Furthermore, we take into account that a specific gene can be mapped to different pathways at the same time. The classification method produces a scoring of all possible mapping positions of the gene in the KEGG hierarchy. Evaluations of our model, which is a combination of a SVM and ranking perceptron approach, show a high prediction performance. Moreover, for signaling pathways we reveal that it is even possible to forecast accurately the membership to individual pathway components. Availability: The R package gene2pathway is a supplement to this article. Contact: h.froehlich@dkfz-heidelberg.de Supplementary Information: Supplementary data are available at Bioinformatics online.
Parameterizing above or below guaranteed values
Authors: Meena Mahajan, Venkatesh Raman, Somnath Sikdar
Venue: Journal of Computer and System Sciences (2009)

We consider new parameterizations of NP-optimization problems that have nontrivial lower and/or upper bounds on their optimum solution size. The natural parameter, we argue, is the quantity above the lower bound or below the upper bound. We show that for every problem in MAX SNP, the optimum value is bounded below by an unbounded function of the input-size, and that the above-guarantee parameterization with respect to this lower bound is fixed-parameter tractable. We also observe that approximation algorithms give nontrivial lower or upper bounds on the solution size and that the above or below guarantee question with respect to these bounds is fixed-parameter tractable for a subclass of NP-optimization problems. We then introduce the notion of 'tight' lower and upper bounds and exhibit a number of problems for which the above-guarantee and below-guarantee parameterizations with respect to a tight bound is fixed-parameter tractable or W-hard. We show that if we parameterize ''sufficiently'' above or below the tight bounds, then these parameterized versions are not fixed-parameter tractable unless P=NP, for a subclass of NP-optimization problems. We also list several directions to explore in this paradigm.
Macroscopic invisible cables
Authors: Nicola M. Pugno
Venue: Microsystem Technologies (2008)

Spiders suggest to us that producing high strength over density ratio invisible cables could be of great importance. In this paper we show that such invisible cables could in principle be built, thanks to carbon nanotube bundles. Theoretical strength of ~10&#x00a0;MPa, Young&#x2019;s modulus of ~0.1&#x00a0;GPa and density of ~0.1&#x00a0;Kg/m3 are estimated. The theoretical strength over density ratio is huge, i.e. that of a single carbon nanotube; the strength of a real, thus defective, invisible cable is estimated to be ~1&#x00a0;MPa. Finally, we demonstrate that such cables can be easily transported in their visible state (with bunched nanotubes) and that an efficient anti-bunching controllable mechanism, involving pressure of ~1&#x00a0;Pa, can control the visible&#x2013;invisible transition, and vice versa.
Leveraging aggregate ratings for improving predictive performance of recommender systems
Authors: Akhmed Umyarov
Venue: Proceedings of the 2008 ACM conference on Recommender systems (2008)

One of the key problems in recommender systems is accurate estimation of unknown ratings of individual items for individual users in terms of the previously specified ratings and other characteristics of items and users. In this thesis, we investigate a way of improving estimations of individual ratings using externally provided properties of aggregate ratings for groups of items and users, such as an externally specified average rating of action movies provided by graduate students or externally specified standard deviation of ratings for comedy movies.
Estimating null values in relational database systems using automatic clustering and multiple regression techniques
Authors: Shu-Ting Chang, Shyi-Ming Chen
Venue: Expert Systems with Applications: An International Journal (2009)

In this paper, we present a new method for estimating null values in relational database systems using automatic clustering and multiple regression techniques. First, we present a new automatic clustering algorithm for clustering numerical data. The proposed automatic clustering algorithm does not need to determine the number of clusters in advance and does not need to sort the data in the database in advance. Then, based on the proposed automatic clustering algorithm and multiple regression techniques, we present a new method to estimate null values in relational database systems. The proposed method estimating null values in relational database systems only needs to process a particular cluster instead of the whole database. It gets a higher average estimation accuracy rate than the existing methods for estimating null values in relational database systems.