ppxscal/embedding_network huggingface dataset:
Approximating mixed Nash equilibria using smooth fictitious play in simultaneous auctions
Authors: Enrico H. Gerding, Zinovi Rabinovich, Andrew Byde, Edith Elkind, Nicholas R. Jennings
Venue: Proceedings of the 7th international joint conference on Autonomous agents and multiagent systems - Volume 3 (2008)

We investigate equilibrium strategies for bidding agents that participate in multiple, simultaneous second-price auctions with perfect substitutes. For this setting, previous research has shown that it is a best response for a bidder to participate in as many such auctions as there are available, provided that other bidders only participate in a single auction. In contrast, in this paper we consider equilibrium behaviour where all bidders participate in multiple auctions. For this new setting we consider mixed-strategy Nash equilibria where bidders can bid high in one auction and low in all others. By discretising the bid space, we are able to use smooth fictitious play to compute approximate solutions. Specifically, we find that the results do indeed converge to &epsilon;-Nash mixed equilibria and, therefore, we are able to locate equilibrium strategies in such complex games where no known solutions previously existed.
Simplifying Public Key Management
Authors: Peter Gutmann
Venue: Computer (2004)

Alternative approaches to public key management offer ease of use, transparency to end users, and low unit cost.
Virtual democratic dialogue? Bringing together citizens and politicians
Authors: Jakob Linaa Jensen
Venue: Information Polity (2003)

How to realize the potential of the Internet for creating virtual public spheres for democratic dialogue has been widely discussed. It has been argued that government should play a more active role in that process. This paper examines a Danish case sponsored by a local government where citizens and politicians were invited to debate via the Internet. It is concluded that the project was quite a success. The overall tone of the debate was respectful and the levels of argumentation, information and deliberation were generally high. Further, the presence of politicians created a debate space consisting of two dimensions and five relations. Two main processes took place within that space: general debates and consultation processes between citizens and politicians. As such, the project achieved a double purpose. Problematically, the project did not succeed in mobilising new groups for political debate. Further, it was a tendency that the politicians tended to dominate the debate leaving less space for debates among citizens.
An Effective Approach for Identifying Evolving Three-Dimensional Structural Motifs in Protein Folding Data
Authors: Hui Yang, Lin Han
Venue: Proceedings of the 4th international conference on Advanced Data Mining and Applications (2008)

Molecular Dynamics-based simulations have been employed to study the protein folding process, in which a protein acquires its functional three-dimensional structure. This has resulted in a large number of protein folding trajectories. As a result, it becomes increasingly important to analyze such data to facilitate a deeper understanding of the protein folding mechanism. In this paper, we focus on identifying important 3D structural motifs in the folding data. We have proposed a multi-step algorithm that is not only computationally efficient but also captures the evolving nature of the folding process. Empirical evaluation demonstrates that such motifs are effective at characterizing a protein's structural evolution in its folding process. We also show that such motifs can be utilized to address important folding issues such as detecting important folding events, and structurally characterizing a folding pathway.
On an Efficient General Line-Clipping Algorithm
Authors: David Rogers, Linda Rybak
Venue: IEEE Computer Graphics and Applications (1985)

The purpose of this note is to bring to the attention of the computer graphics community a powerful, efficient, general two- and three-dimensional line-clipping algorithm originated by Cyrus and Beck.1 This algorithm appears to be virtually unknown to the computer graphics community. For example, the algorithm is neither referenced nor discussed by Newman and Sproull2 of Foley and van Dam.3 Further, it is not referenced in the current literature in the field. For example, the algorithm was unknown to Liang and Barsky at the time they developed their recent line-and polygon-clipping algorithms.
Multi-robot Route Following Using Omnidirectional Vision and Appearance-Based Representation of the Environment
Authors: Luis Payá, Oscar Reinoso, Arturo Gil, Javier Sogorb
Venue: Proceedings of the 3rd international workshop on Hybrid Artificial Intelligence Systems (2008)

In this work, a framework to carry out multi-robot route following is presented. With this approach, a team of mobile robots can follow a route that a leader robot has previously recorded or is recording at the moment. Each robot has a catadioptric system on it that provides omnidirectional images of the environment. To carry out the localization and control of each robot during route following, we have made use of an appearance-based philosophy in combination with compression techniques in the Fourier Domain and the Principal Components Analysis subspace. These techniques are especially interesting in the case of panoramic images due to their invariance to orientation and robustness to small changes in the environment. Several experiments with a team of mobile robots have been carried out to demonstrate the robustness of the approach in realistic office and laboratory environments.
Solutions of integral and integro-differential equation systems by using differential transform method
Authors: Aytac Arikoglu, Ibrahim Ozkol
Venue: Computers Mathematics with Applications (2008)

In this study, differential transform method (DTM) is applied to both integro-differential and integral equation systems. The method is further expanded with a formulation to treat Fredholm integrals. If the system considered has a solution in terms of the series expansion of known functions, this powerful method catches the exact solution. So as to show this capability and robustness, some systems of integral and integro-differential equations are solved as numerical examples.
Automatic Mutual Exclusion and Atomicity Checks
Authors: Martín Abadi
Venue: Concurrency, Graphs and Models: Essays Dedicated to Ugo Montanari on the Occasion of His 65th Birthday (2008)

This paper provides an introduction to the Automatic Mutual Exclusion (AME) programming model and to its formal study, through the AME calculus. AME resembles cooperative multithreading; in the intended implementations, however, software transactional memory supports the concurrent execution of atomic fragments. This paper also studies simple dynamic and static mechanisms for atomicity checks in AME.
Revisit controlled lagrangians for spherical inverted pendulum
Authors: Guangyu Liu, Subhash Challa, Long-Guang Yu
Venue: Proceedings of the 8th WSEAS International Conference on Robotics, Control and Manufacturing Technology (2008)

Recently, passivity based control theory (energy approaches) has undergone a breakthrough in dealing with underactated mechanical systems with two successful and similar tools, controlled Lagrangians and controlled Hamiltanians (IDA-PBC). Because of the complexity, successful case studies are lacking, for example, MIMO, underactuated and unstable systems. The seminal paper of controlled Lagrangians proposed by Bloch and his colleagues presented a benchmark example-a simplified spherical inverted pendulum on a cart but the detailed design and its verification were neglected. To compensate this ignorance, the note revisits their design idea by addressing explicit control functions for a similar device motivated by real applications. Some observations are given through computer simulation. At the courtesy of the original idea, the case study is known to be the first MIMO, underactuated and unstable system stabilized in full state space via energy approaches.
A smaller planar graph without 4-, 5-cycles and intersecting triangles that is not 3-choosable
Authors: De-Qiang Wang, Yu-Peng Wen, Ke-Lun Wang
Venue: Information Processing Letters (2008)

In 2006, Montassier et al. constructed a planar graph without 4-, 5-cycles and intersecting triangles that is not 3-choosable [M. Montassier, A. Raspaud, W. Wang, Bordeaux 3-color conjecture and 3-choosability, Discrete Math. 306 (2006) 573-579]. It has 506 vertices. In this paper, we construct a smaller planar graph with the same properties. The planar graph has 380 vertices.
Fault detection using virtual environment and wireless robot
Authors: Emil Voisan, Constantin Volosencu, Adrian Leu, Florin Dragan
Venue: Proceedings of the 9th WSEAS International Conference on International Conference on Automation and Information (2008)

Intelligent robots that are able to efficiently interact with working environment is an actual trend today, the classic approach is to use robot sensors to discover surroundings and based on that readings to take decisions. Our proposal is based on a virtual environment to describe the objects from the real environment and based on this environment the decisions are taken and transmitted to the "real" robot.
A Risk-Sensitive Portfolio with Mean and Variance of Fuzzy Random Variables
Authors: Yuji Yoshida
Venue: Proceedings of the 4th international conference on Intelligent Computing: Advanced Intelligent Computing Theories and Applications - with Aspects of Artificial Intelligence (2008)

This paper discusses a risk-sensitive portfolio problem, where the objective function is defined by randomness and fuzziness, and it introduces the perception-based extension of the expectation and the variance for fuzzy random variables. Fuzzy random variables are estimated by mean and variance with ¿-mean functions and evaluation weights: A possibility-necessity weight ¿ for subjective estimation, and a pessimistic-optimistic index ¿ for subjective decision. A solution of the risk-sensitive portfolio problem is derived by quadratic programming approach.
Implementing a Knowledge-Driven Hierarchical Context Model in a Medical Laboratory Information System
Authors: Jaan Pruulmann, Jan Willemson
Venue: Proceedings of the 2008 The Third International Multi-Conference on Computing in the Global Information Technology (iccgi 2008) (2008)

This paper discusses a context model developed for medical laboratory information system of Tartu University Hospital laboratories (in Tartu, Estonia). Due to the size, structure and complex history of the laboratory infrastructure, managing user communications and even achieving a common vocabulary has become a serious task. Most of the concepts used by the laboratory personnel depend on the particular cultural, organizational or other types of context, thus reducing the problem of user communications to context management. In this paper we present a cross-linked hierarchical approach to building a context management engine that uses open context space and a flexible attribute value delegation mechanism. We discuss development objectives of the laboratory information system together with the design decisions made and summarize the first user experience. Even though the context engine is currently implemented for use in laboratory environment, its architecture is general enough to support a considerably larger variety of application domains.
More on the order of prolongations and restrictions
Authors: Rob Stevenson
Venue: Applied Numerical Mathematics (2008)

For the analysis of multi-grid methods applied to finite difference discretizations, two definitions of orders of intergrid transfer operators are being used. The order is either defined in terms of the symbol of the transfer operator, i.e., its Fourier transform, or as the order of polynomials being preserved. In [J. Comput. Appl. Math. 32 (3) (1990) 423-429], Hemker showed that the second definition is stronger than the first one. In this note, we show that both definitions are even equivalent.
Primary total hip replacement in childhood, adolescence and young patients: Quality and outcome of clinical studies
Authors: M. Jäger, M. J. W. Begg, J. Ready, B. Bittersohl, M. Millis, R. Krauspe, T. S. Thornhill
Venue: Technology and Health Care (2008)

Objective: The present meta-analysis illustrates relevant information about hip replacement in young patients that has been published during the past 3 decades. Material and methods: Based on a MedLine literature review a total of 95 studies were evaluated. Parameters for evaluation of study quality and outcome were implant survival rates (ISR), number of patients, indications, follow-up, surgical approaches and number of surgeons. Results: Most studies consider patient numbers <50. In 33 studies one implant system was applied compared to 65 studies in which more than one system was used. Most studies include different surgical approaches. 20% of all studies contained neither the number of surgeons, nor the type of surgical approach. The overall ISR could be evaluated in 67 studies. Sufficient data about the ISR of stem and/or sockets were available in 50 papers. Conclusions: Most published studies analyzed inhomogeneous study populations; study variables vary as do the implants used for treatment.
Predicting Listener Backchannels: A Probabilistic Multimodal Approach
Authors: Louis-Philippe Morency, Iwan Kok, Jonathan Gratch
Venue: Proceedings of the 8th international conference on Intelligent Virtual Agents (2008)

During face-to-face interactions, listeners use backchannel feedback such as head nods as a signal to the speaker that the communication is working and that they should continue speaking. Predicting these backchannel opportunities is an important milestone for building engaging and natural virtual humans. In this paper we show how sequential probabilistic models (e.g., Hidden Markov Model or Conditional Random Fields) can automatically learn from a database of human-to-human interactions to predict listener backchannels using the speaker multimodal output features (e.g., prosody, spoken words and eye gaze). The main challenges addressed in this paper are automatic selection of the relevant features and optimal feature representation for probabilistic models. For prediction of visual backchannel cues (i.e., head nods), our prediction model shows a statistically significant improvement over a previously published approach based on hand-crafted rules.
The Tractability Frontier for NFA Minimization
Authors: Henrik Björklund, Wim Martens
Venue: Proceedings of the 35th international colloquium on Automata, Languages and Programming, Part II (2008)

We essentially show that minimizing finite automata is NP-hard as soon as one deviates from the class of deterministic finite automata. More specifically, we show that minimization is NP-hard for all finite automata classes that subsume the class that is unambiguous, allows at most one state q with a non-deterministic transition for at most one alphabet symbol a, and is allowed to visit state q at most once in a run. Furthermore, this result holds even for automata that only accept finite languages.
Convex Hodge Decomposition of Image Flows
Authors: Jing Yuan, Gabriele Steidl, Christoph Schnörr
Venue: Proceedings of the 30th DAGM symposium on Pattern Recognition (2008)

The total variation (TV) measure is a key concept in the field of variational image analysis. Introduced by Rudin, Osher and Fatemi in connection with image denoising, it also provides the basis for convex structure-texture decompositions of image signals, image inpainting, and for globally optimal binary image segmentation by convex functional minimization. Concerning vector-valued image data, the usual definition of the TV measure extends the scalar case in terms of the L 1-norm of the gradients.In this paper, we show for the case of 2D image flows that TV regularization of the basic flow components (divergence, curl) leads to a mathematically more natural extension. This regularization provides a convex decomposition of motion into a richer structure component and texture. The structure component comprises piecewise harmonic fields rather than piecewise constant ones. Numerical examples illustrate this fact. Additionally, for the class of piecewise harmonic flows, our regularizer provides a measure for motion boundaries of image flows, as does the TV-measure for contours of scalar-valued piecewise constant images.
Optimized staffing for product releases and its application at Chartwell Technology
Authors: Puneet Kapur, An Ngo-The, Günther Ruhe, Andrew Smith
Venue: Journal of Software Maintenance and Evolution: Research and Practice (2008)

Release planning for incremental software development assigns features to releases such that technical, resource, risk and budget constraints are met. Each feature offers a piece of functionality. A feature can be offered as part of a release only if all its necessary tasks are done before the given release date. These tasks require different skills. Staffing for product releases as considered in this paper is the process of assigning human resources from a given pool of developers who might have varying levels of skill to perform different tasks. In addition to that, we consider time windows of absence of the developers. The primary goal of staffing is to provide product releases of best quality where quality means offering the most attractive features to customers in a timely manner. We call the problem STAFF-PRO. The problem is known to be NP-complete. Consequently, we have to be satisfied with solutions that are sufficiently good, but not necessarily optimal in the case of mid-sized or large problems. Search-based methods relying on meta-heuristics have been proven to be successful in similar contexts. In this research, a focused search (FS) method is presented. This refers to a two-phased solution approach where Phase 1 applies integer linear programming to a relaxed version of the full problem. Its solution is used as a starting point to perform FS in a reduced search space in Phase 2. The search itself is conducted by a genetic algorithm. It generates a solution that fulfills all the stated resource and scheduling constraints and is of a proven degree of optimality. We performed an empirical analysis of the proposed solution approach by comparing FS and unfocused search (UFS) (without Phase 1) for a series of 200 test examples. On average, FS performs about 15% better than UFS. The whole method was applied as an industrial case study performed at Chartwell Technology. The case study demonstrates that application of the FS method to STAFF-PRO (i) allows a reduction in the time needed for generating acceptable staffing plans, (ii) generates plans of proven quality that are better than manual plans and (iii) supports the various types of re-planning necessary for varying parameters, budgets and resource. Copyright &copy; 2008 John Wiley Sons, Ltd.
Evaluating host intrusion detection systems
Authors: Michel Cukier
Venue:  (2007)

Host Intrusion Detection Systems (HIDSs) are critical tools needed to provide in-depth security to computer systems. Quantitative metrics for HIDSs are necessary for comparing HIDSs or determining the optimal operational point of a HIDS. While HIDSs and Network Intrusion Detection Systems (NIDSs) greatly differ, similar evaluations have been performed on both types of IDSs by assessing metrics associated with the classification algorithm (e.g., true positives, false positives). This dissertation motivates the necessity of additional characteristics to better describe the performance and effectiveness of HIDSs.The proposed additional characteristics are the ability to collect data where an attack manifests (visibility), the ability of the HIDS to resist attacks in the event of an intrusion (attack resiliency), the ability to timely detect attacks (efficiency), and the ability of the HIDS to avoid interfering with the normal functioning of the system under supervision (transparency). For each characteristic, we propose corresponding quantitative evaluation metrics.To measure the effect of visibility on the detection of attacks, we introduce the probability of attack manifestation and metrics related to data quality (i.e., relevance of the data regarding the attack to be detected). The metrics were applied empirically to evaluate filesystem data, which is the data source for many HIDSs.To evaluate attack resiliency we introduce the probability of subversion, which we estimate by measuring the isolation between the HIDS and the system under supervision. Additionally, we provide methods to evaluate time delays for efficiency, and performance overhead for transparency. The proposed evaluation methods are then applied to compare two HIDSs.Finally, we show how to integrate the proposed measurements into a cost framework. First, mapping functions are established to link operational costs of the HIDS with the metrics proposed for efficiency and transparency. Then we show how the number of attacks detected by the HIDS not only depends on detection accuracy, but also on the evaluation results of visibility and attack resiliency.
Affect Simulation with Primary and Secondary Emotions
Authors: Christian Becker-Asano, Ipke Wachsmuth
Venue: Proceedings of the 8th international conference on Intelligent Virtual Agents (2008)

In this paper the WASABI Affect Simulation Architecture is introduced, in which a virtual human's cognitive reasoning capabilities are combined with simulated embodiment to achieve the simulation of primary and secondary emotions. In modeling primary emotions we follow the idea of "Core Affect" in combination with a continuous progression of bodily feeling in three-dimensional emotion space (PAD space), that is only subsequently categorized into discrete emotions. In humans, primary emotions are understood as onto-genetically earlier emotions, which directly influence facial expressions. Secondary emotions, in contrast, afford the ability to reason about current events in the light of experiences and expectations. By technically representing aspects of their connotative meaning in PAD space, we not only assure their mood-congruent elicitation, but also combine them with facial expressions, that are concurrently driven by the primary emotions. An empirical study showed that human players in the Skip-Bo scenario judge our virtual human MAX significantly older when secondary emotions are simulated in addition to primary ones.
B-spline neural network design using improved differential evolution for identification of an experimental nonlinear process
Authors: Leandro dos Santos Coelho, Fabio A. Guerra
Venue: Applied Soft Computing (2008)

B-Spline Neural Network (BSNN), a type of basis function neural network, is trained by gradient-based methods which may fall into local minima during the learning procedure. To overcome the limitations encountered by gradient-based optimization methods, we propose differential evolution (DE) - an evolutionary computation methodology - which can provide a stochastic search to adjust the control points of a BSNN. In this paper, we propose six DE approaches using chaotic sequences based on logistic mapping to train a BSNN. Chaos describes the complex behavior of a nonlinear deterministic system. The application of chaotic sequences instead of random sequences in DE is a powerful strategy to diversify the DE population and improve the DE's performance in preventing premature convergence to local minima. The numerical results presented here indicate that chaotic DE was effective for building a good BSNN model for the nonlinear identification of an experimental nonlinear yo-yo motion control system.