ppxscal/embedding_network huggingface dataset:
The Glauber Dynamics for Colourings of Bounded Degree Trees
Authors: Brendan Lucier, Michael Molloy, Yuval Peres
Venue: Proceedings of the 12th International Workshop and 13th International Workshop on Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (2009)

We study the Glauber dynamics Markov chain for k-colourings of trees with maximum degree Δ. For k ¿ 3, we show that the mixing time on every tree is at most n O(1 + Δ/(k logΔ)). This bound is tight up to the constant factor in the exponent, as evidenced by the complete tree. Our proof uses a weighted canonical paths analysis and a variation of the block dynamics that exploits the differing relaxation times of blocks.
The Isomorphism Problem for k-Trees Is Complete for Logspace
Authors: Johannes Köbler, Sebastian Kuhnert
Venue: Proceedings of the 34th International Symposium on Mathematical Foundations of Computer Science 2009 (2009)

We show that k-tree isomorphism can be decided in logarithmic space by giving a logspace canonical labeling algorithm. This improves over the previous StUL upper bound and matches the lower bound. As a consequence, the isomorphism, the automorphism, as well as the canonization problem for k-trees are all complete for deterministic logspace. We also show that even simple structural properties of k-trees are complete for logspace.
An augmented mixed finite element method for 3D linear elasticity problems
Authors: Gabriel N. Gatica, Antonio Márquez, Salim Meddahi
Venue: Journal of Computational and Applied Mathematics (2009)

In this paper we introduce and analyze a new augmented mixed finite element method for linear elasticity problems in 3D. Our approach is an extension of a technique developed recently for plane elasticity, which is based on the introduction of consistent terms of Galerkin least-squares type. We consider non-homogeneous and homogeneous Dirichlet boundary conditions and prove that the resulting augmented variational formulations lead to strongly coercive bilinear forms. In this way, the associated Galerkin schemes become well posed for arbitrary choices of the corresponding finite element subspaces. In particular, Raviart-Thomas spaces of order 0 for the stress tensor, continuous piecewise linear elements for the displacement, and piecewise constants for the rotation can be utilized. Moreover, we show that in this case the number of unknowns behaves approximately as 9.5 times the number of elements (tetrahedrons) of the triangulation, which is cheaper, by a factor of 3, than the classical PEERS in 3D. Several numerical results illustrating the good performance of the augmented schemes are provided.
Innovation Method for Dynamic Independent Component Analysis: A New Concept and Algorithm
Authors: Yu Yonglin, Wang Gang
Venue: Proceedings of the 2009 WRI Global Congress on Intelligent Systems - Volume 02 (2009)

The inner time-structure information is consideredfor the dynamic independent component analysis (DICA)model, and the new concept of innovation and correspondingalgorithm are presented. When the innovation is applied inDICA, a new linear mixing model of innovation DICA (IDICA)can be obtained in which the assumptions of independence andnon-Gaussianity for the basic ICA model are also satisfied,and the non-Gaussianity of latent components increase.What’s more, the mixing matrix (or demixing matrix)estimated from IDICA model is also available for originalDICA model. Then the new algorithm of (IDICA) is presented,and the effects of IDICA are discussed. It is validated that itcan accelerate the convergence rate with the increasing of thelatent component’s non-Gaussianity, but has little influence onthe convergence accuracy. In performing innovation, theadaptive filter based on Minimum Square Error (MSE) isproposed. The experimental results show the new method’sefficient and available.
Effect of Navigation Aids and Landmarks on Acquisition of Spatial Knowledge in Virtual Environments
Authors: Zuo Wuheng, Xu Baihua, Yuan He, Feng Zhilin
Venue: Proceedings of the 2009 First International Workshop on Database Technology and Applications (2009)

The effect of navigation aids and landmarkson spatial learning was investigated when participants repeatedly navigated four complex three-dimensional virtual mazes. The study was divided into two main phases: learning and a test of learning transfer. The learning phase consisted of participants directly navigating in one of the four virtual mazes with or without navigation aids and landmarks. Learning transfer was examined by testing navigation tasks in the environment without the use of the navigation aids. Findings show that the combined impact of both navigation aids and landmarks on spatial knowledge acquisition in navigation tasks.
Finding diverse and similar solutions in constraint programming
Authors: Emmanuel Hebrard, Brahim Hnich, Barry O'Sullivan, Toby Walsh
Venue: Proceedings of the 20th national conference on Artificial intelligence - Volume 1 (2005)

It is useful in a wide range of situations to find solutions which are diverse (or similar) to each other. We therefore define a number of different classes of diversity and similarity problems. For example, what is the most diverse set of solutions of a constraint satisfaction problem with a given cardinality? We first determine the computational complexity of these problems. We then propose a number of practical solution methods, some of which use global constraints for enforcing diversity (or similarity) between solutions. Empirical evaluation on a number of problems show promising results.
A computational analysis of the tournament equilibrium set
Authors: Felix Brandt, Felix Fischer, Paul Harrenstein, Maximilian Mair
Venue: Proceedings of the 23rd national conference on Artificial intelligence - Volume 1 (2008)

A recurring theme in AI and multiagent systems is how to select the "most desirable" elements given a binary dominance relation on a set of alternatives. Schwartz's tournament equilibrium set (TEQ) ranks among the most intriguing, but also among the most enigmatic, tournament solutions proposed so far in this context. Due to its unwieldy recursive definition, little is known about TEQ. In particular, its monotonicity remains an open problem to date. Yet, if TEQ were to satisfy monotonicity, it would be a very attractive solution concept refining both the Banks set and Dutta's minimal covering set. We show that the problem of deciding whether a given alternative is contained in TEQ is NP-hard. Furthermore, we propose a heuristic that significantly outperforms the naive algorithm for computing TEQ. Early experimental results support the conjecture that TEQ is indeed monotonic.
Opening the Black Box: Exploring the Effect of Transformation on Online Service Delivery in Local Governments
Authors: Anne Fleur Veenstra, Arre Zuurmond
Venue: Proceedings of the 8th International Conference on Electronic Government (2009)

To enhance the quality of their online service delivery, many government organizations seek to transform their organization beyond merely setting up a front office. This transformation includes elements such as the formation of service delivery chains, the adoption of a management strategy supporting process orientation and the implementation of enterprise architecture. This paper explores whether undertaking this transformation has a positive effect on the quality of online service delivery, using data gathered from seventy local governments. We found that having an externally oriented management strategy in place, adopting enterprise architecture, aligning information systems to business and sharing activities between processes and departments are positively related to the quality of online service delivery. We recommend that further research should be carried out to find out whether dimensions of organizational development too have an effect on online service delivery in the long term.
P300 Based Single Trial Independent Component Analysis on EEG Signal
Authors: Kun Li, Ravi Sankar, Yael Arbel, Emanuel Donchin
Venue: Proceedings of the 5th International Conference on Foundations of Augmented Cognition. Neuroergonomics and Operational Neuroscience: Held as Part of HCI International 2009 (2009)

A Brain Computer Interface (BCI) is a device that allows the user to communicate with the world without utilizing voluntary muscle activity (i.e., using only the electrical activity of the brain). It makes use of the well-studied observation that the brain reacts differently to different stimuli, as a function of the level of attention allotted to the stimulus stream and the specific processing triggered by the stimulus. In this article we present a single trial independent component analysis (ICA) method that is working with a BCI system proposed by Farwell and Donchin. It can dramatically reduce the signal processing time and improve the data communicating rate. This ICA method achieved 76.67% accuracy on single trial P300 response identification.
Simple 3D Reconstruction of Single Indoor Image with Perspective Cues
Authors: Jingyuan Huang, Bill Cowan
Venue: Proceedings of the 2009 Canadian Conference on Computer and Robot Vision (2009)

Image-based modeling is a longstanding research topic in computer vision. Reconstruction based on a single image is a particularly difficult example. This paper presents a simple reconstruction method that quickly extracts 3D geometric structure from a single indoor photograph consisting mainly of orthogonal planes.Our method takes advantage of perspective cues and uses basic knowledge of photography and achieves a fully automated reconstruction of the scene.
An Extensible I/O Performance Analysis Framework for Distributed Environments
Authors: Benjamin Eckart, Xubin He, Hong Ong, Stephen L. Scott
Venue: Proceedings of the 15th International Euro-Par Conference on Parallel Processing (2009)

As distributed systems increase in both popularity and scale, it becomes increasingly important to understand as well as to systematically identify performance anomalies and potential opportunities for optimization. However, large scale distributed systems are often complex and non-deterministic due to hardware and software heterogeneity and configurable runtime options that may boost or diminish performance. It is therefore important to be able to disseminate and present the information gleaned from a local system under a common evaluation methodology so that such efforts can be valuable in one environment and provide general guidelines for other environments. Evaluation methodologies can conveniently be encapsulated inside of a common analysis framework that serves as an outer layer upon which appropriate experimental design and relevant workloads (benchmarking and profiling applications) can be supported.In this paper we present ExPerT, an Extensible Performance Toolkit. ExPerT defines a flexible framework from which a set of benchmarking, tracing, and profiling applications can be correlated together in a unified interface. The framework consists primarily of two parts: an extensible module for profiling and benchmarking support, and a unified data discovery tool for information gathering and parsing. We include a case study of disk I/O performance in virtualized distributed environments which demonstrates the flexibility of our framework for selecting benchmark suite, creating experimental design, and performing analysis.
A Parameter-Based Model for Generating Culturally Adaptive Nonverbal Behaviors in Embodied Conversational Agents
Authors: Afia Akhter Lipi, Yukiko Nakano, Matthias Rehm
Venue: Proceedings of the 5th International on ConferenceUniversal Access in Human-Computer Interaction. Part II: Intelligent and Ubiquitous Interaction Environments (2009)

The goal of this paper is to integrate culture as a computational term in embodied conversational agents by employing an empirical data-driven approach as well as a theoretical model-driven approach. We propose a parameter-based model that predicts nonverbal expressions appropriate for specific cultures. First, we introduce the Hofstede theory to describe socio-cultural characteristics of each country. Then, based on the previous studies in cultural differences of nonverbal behaviors, we propose expressive parameters to characterize nonverbal behaviors. Finally, by integrating socio-cultural characteristics and nonverbal expressive characteristics, we establish a Bayesian network model that predicts posture expressiveness from a country name, and vice versa.
Failboxes: Provably Safe Exception Handling
Authors: Bart Jacobs, Frank Piessens
Venue: Proceedings of the 23rd European Conference on ECOOP 2009 --- Object-Oriented Programming (2009)

The primary goal of exception mechanisms is to help ensure that when an operation fails, code that depends on the operation's successful completion is not executed (a property we call dependency safety). However, the exception mechanisms of current mainstream programming languages make it hard to achieve dependency safety, in particular when objects manipulated inside a try block outlive the try block.Many programming languages, mechanisms and paradigms have been proposed that address this issue. However, they all depart significantly from current practice. In this paper, we propose a language mechanism called failboxes. When applied correctly, failboxes have no significant impact on the structure, the semantics, or the performance of the program, other than to eliminate the executions that violate dependency safety.Specifically, programmers may create failboxes dynamically and execute blocks of code in them. Once any such block fails, all subsequent attempts to execute code in the failbox will fail. To achieve dependency safety, programmers simply need to ensure that if an operation B depends on an operation A, then A and B are executed in the same failbox. Furthermore, failboxes help fix the unsafe interaction between locks and exceptions and they enable safe cancellation and robust resource cleanup. Finally, the Fail Fast mechanism prevents liveness issues when a thread is waiting on a failed thread.We give a formal syntax and semantics of the new constructs, and prove dependency safety. Furthermore, to show that the new constructs are easy to reason about, we propose proof rules in separation logic. The theory has been machine-checked.
Social network aided multicast delivery scheme for human contact-based networks
Authors: Mooi Choo Chuah
Venue: Proceedings of the 1st Annual Workshop on Simplifying Complex Network for Practitioners (2009)

Mobile devices carried by people form dynamic networks. Understanding the social structures within the human mobility traces captured from the mobile devices help us to design more efficient message dissemination schemes. People who are in multiple communities are good message carriers. Thus, the ability to identify the different communities efficiently from the various communication traces e.g. contact traces from users' mobile devices is important. In this paper, using some human mobility traces from the real world, we first identify nodes that can play key roles using some social network metrics. Then, we investigate the usefulness of utilizing the keyrole nodes information in the design of multicast delivery schemes in human contact-based networks. Our results indicate that using such information can achieve similar delivery performance as the multi-copy epidemic scheme but at a much smaller communication cost.
3D Reconstruction of Colon Segments from Colonoscopy Images
Authors: DongHo Hong, Wallapak Tavanapong, Johnny Wong, JungHwan Oh, Piet C. de Groen
Venue: Proceedings of the 2009 Ninth IEEE International Conference on Bioinformatics and Bioengineering (2009)

A new algorithm for reconstruction of a 3D virtual colon segment from an individual image captured from colonoscopy is presented. Colonoscopy is currently the gold standard method for detection and prevention of colorectal cancer. However, the protective effect depends on the amount of colon mucosa that is actually seen by the endoscopist. The proposed algorithm takes contours of colon folds in the image as input and calculates the depth and the slant angle of each fold. Finally, the colon mucosa is created using Cubic Bezier Curve interpolation between the folds. The proposed algorithm is an important step toward 3D reconstruction of the virtual colon from video of an entire colonoscopy procedure. The reconstruction is potentially useful to estimate percent of colon mucosa inspected by the endoscopist.
Minimum Delay Data Gathering in Radio Networks
Authors: Jean-Claude Bermond, Nicolas Nisse, Patricio Reyes, Hervé Rivano
Venue: Proceedings of the 8th International Conference on Ad-Hoc, Mobile and Wireless Networks (2009)

The aim of this paper is to design efficient gathering algorithms (data collection) in a Base Station of a wireless multi hop grid network when interferences constraints are present. We suppose the time is slotted and that during one time slot (step) each node can transmit to one of its neighbours at most one data item. Each device is equipped with a half duplex interface; so a node cannot both receive and transmit simultaneously. During a step only non interfering transmissions can be done. In other words, the non interfering calls done during a step will form a matching. The aim is to minimize the number of steps needed to send to the base station a set of messages generated by the nodes, this completion time is also denoted makespan of the call scheduling. The best known algorithm for open-grids was a multiplicative 1.5-approximation algorithm [Revah, Segal 07]. In such topologies, we give a very simple +2 approximation algorithm and then a more involved +1 approximation algorithm. Moreover, our algorithms work when no buffering is allowed in intermediary nodes, i.e., when a node receives a message at some step, it must transmit it during the next step.
Using NoC routers as processing elements
Authors: Sílvio Fernandes, Bruno C. Oliveira, Ivan Saraiva Silva
Venue: Proceedings of the 22nd Annual Symposium on Integrated Circuits and System Design: Chip on the Dunes (2009)

The integration technology has increased at the point where the development of Multi-Core processor architectures is a market reality nowadays. In this scenario, the interconnection network has a critical function when the number of cores increases, becoming impossible to use bus-based solutions. This paper approaches this problem with a new NoC-based architecture and a new computation mode. It proposes the utilization of network-onchip not only as an interconnection network but as well the processing datapath, which has great power of parallelism.
Sequential Principal Component Analysis - A Hardware-Implementable Transform for Image Compression
Authors: Tuan A. Duong, Vu A. Duong
Venue: Proceedings of the Third IEEE International Conference on Space Mission Challenges for Information Technology (2009)

This paper presents the JPL-developed Sequential Principal Component Analysis (SPCA) algorithm for feature extraction / image compression, based on “dominant-term selection” unsupervised learning technique that requires an order-of-magnitude lesser computation and has simpler architecture compared to the state of the art gradient-descent techniques.This algorithm is inherently amenable to a compact, low power and high speed VLSI hardware embodiment.The paper compares the lossless image compression performance of the JPL’s SPCA algorithm with the state of the art JPEG2000, widely used due to its simplified hardware implementability.JPEG2000 is not an optimal data compression technique because of its fixed transform characteristics, regardless of its data structure.On the other hand, conventional Principal Component Analysis based transform (PCA-transform) is a data-dependent-structure transform.However, it is not easy to implement the PCA in compact VLSI hardware, due to its highly computational and architectural complexity.In contrast, the JPL’s “dominant-term selection” SPCA algorithm allows, for the first time, a compact, low-power hardware implementation of the powerful PCA algorithm.This paper presents a direct comparison of the JPL’s SPCA versus JPEG2000, incorporating the Huffman and arithmetic coding for completeness of the data compression operation.The simulation results show that JPL’s SPCA algorithm is superior as an optimal data-dependent-transform over the state of the art JPEG2000. When implemented in hardware, this technique is projected to be ideally suited to future NASA missions for autonomous on-board image data processing to improve the bandwidth of communication.
Multi-layer framework for analysing and managing routing configurations
Authors: Félix J. García Clemente, Gregorio Martínez Pérez, Antonio F. Gómez Skarmeta
Venue: Computers and Electrical Engineering (2009)

Several research works have shown that the process of Internet routing configuration is error-prone. The primary method used by operators to determine whether their routing configurations are correct is to try them out in operation. A more advanced method is the static analysis of router configurations before they are deployed. We believe that there is a need of broader approaches to verify router configurations automatically and continuously, that is, without human intervention before and after they are deployed. This paper describes a multi-layer analysis framework for configuration checking, which includes three analysis tasks: static analysis before the configuration is deployed; runtime analysis after the configuration is deployed, which is based on routing event monitoring; and active analysis based on checking external information provided by third-parties. We also present the most relevant details of the implementation of our framework.
Impacts of geographical knowledge, spatial ability and environmental cognition on image searches supported by GIS software
Authors: Pei-Lan Lei, Gloria Yi-Ming Kao, Sunny S. J. Lin, Chuen-Tsai Sun
Venue: Computers in Human Behavior (2009)

Google Earth search function was used to study the impacts of small-scale spatial ability, large-scale environmental cognition, and geographical knowledge on new technology usage. The participants were 153 junior high students from central Taiwan. Geography grades served as indicators of prior knowledge, mental rotation and abstract reasoning skills as indicators of spatial ability, and sketch maps of school neighborhoods as indicators of environmental cognition (including landmark representation, intersection representation, and frame of reference). Lastly, the authors announced the landmarks searching worksheet and asked the participants to accomplish 16 familiar and unfamiliar landmark searching tasks using Google Earth with keyword search function disabled. The result showed the strongest predictor of landmark searching performance is 'frame of reference' in environmental cognition, followed by 'mental rotation' of spatial ability, 'landmark representation' of environmental cognition, and geographical knowledge. Google Earth landmark searches require complex cognitive processing; therefore, our conclusion is that GIS-supported image search activities give students good practice of active knowledge construction.
Workload Assessment in Field Using the Ambulatory CUELA System
Authors: Rolf Ellegast, Ingo Hermanns, Christoph Schiefer
Venue: Proceedings of the 2nd International Conference on Digital Human Modeling: Held as Part of HCI International 2009 (2009)

Ambulatory assessment of physical workloads in field is necessary to investigate the risk of work-related musculoskeletal disorders (MSD). Since more than ten years the BGIA is developing and using the motion and force capture system CUELA (computer-assisted recording and long-term analysis of musculoskeletal load), which is designed for whole-shift recordings and analysis of work-related postural and mechanical loads in ergonomic field analysis. This article gives an overview of the actual state of development and some applications of the system.