ppxscal/embedding_network huggingface dataset:
Building a 100 Mpixel graphics device for the OptIPuter
Authors: Bram Stolk, Paul Wielinga
Venue: Future Generation Computer Systems (2006)

Wide area optical lambda networks create new possibilities for data-intensive scientific research and collaboration. One initiative to create novel infrastructure is the OptIPuter project which aims to build a distributed virtual computer using optical networks. At the iGrid2005 venue, an experiment was conducted on how a 100 Mpixel display device in San Diego could be driven by a remote 100 Mpixel graphics device in Amsterdam. The experiment showed the viability of such a setup, thereby validating one specific part of the OptIPuter concept: geographic separation of 100 Mpixel graphics- and display device. A key element in our setup is the use of unreliable communication.
An LMI Approach for Reliable PTZ Camera Self-Calibration
Authors: Hongdong Li, Chunhua Shen
Venue: Proceedings of the IEEE International Conference on Video and Signal Based Surveillance (2006)

PTZ (Pan-Tilt-Zoom) cameras are widely used for large-area video surveillance. For many visual tracking and video analysis tasks, an accurate camera calibration is very important. Traditional off-line camera calibration algorithms are often not satisfactory because some of the PTZ camera intrinsic parameters (e.g., focal length) may change during working. Despite of their theoretical elegance, existing on-line camera self-calibration algorithms are not satisfactory either, because of the lack of numerical stability. This paper proposes a new method based on LMI (linear matrix inequality) optimization. This method automatically incorporates the required positive-definiteness constraint into the computation, thus delivers more reliable and more stable results. Experiments on both synthetic data and real images have validated the advantages of our method.
Modeling modern methods in high school physics classes
Authors: Hal Scheintaub
Venue: Proceedings of the 7th international conference on Learning sciences (2006)

Interactive computer models and simulations can extend traditional learning in high school biology classes (Scheintaub, 2004). Results of this study show that computer models can enhance high school physics learning, too. They do so by extending experiences beyond the limits imposed by text and lab. Computer models complement data gathering and analysis software to bring inquiry to the classroom. The author proposes that validation is critical to a model's effectiveness as a learning tool.
Verification and validation of simulation models
Authors: Robert G. Sargent
Venue: Proceedings of the 37th conference on Winter simulation (2005)

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a recommended procedure for model validation is presented; and accreditation is briefly discussed.
Application of higher order spectra to multi-scale deconvolution of sensor array signals
Authors: A. El-Jaroudi, T. Akgul, M. Simaan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing,1994. on IEEE International Conference - Volume 04 (1994)

We present a solution to the multi-scale deconvolution problem using higher order spectra where the data to be deconvolved consist of noise corrupted sensor array measurements. The model assumes that the data are generated as a convolution of an unknown wavelet with linearly time-scaled versions of an unknown signal (reflectivity sequence). This type of data occurs in many signal processing applications, including radar, sonar and seismic processing. Our approach relies on exploiting the redundancy in the measurements due to time-scaling, and does not require knowledge of the wavelet or the signal. We formulate and solve the deconvolution problem as a quadratic minimization subject to a quadratic constraint in the sum-of-cumulants domain. The formulation using higher-order spectra reduces the effect of additive Gaussian noise on the accuracy of the results when compared to the standard time-domain formulation.
A Processor for Genetic Algorithm using Dynamically Reconfigurable Memory
Authors: Akinori KANASUGI, Akihiko TSUKAHARA
Venue: Proceedings of the 2006 International Conference on Hybrid Information Technology - Volume 01 (2006)

This paper proposes a novel processor for genetic algorithm (GA) using dynamically reconfigurable memory. In general GA, number of population is always constant. However, accuracy of solution is low at first-half stage. Therefore, the number of population is doubled at the expense of accuracy of solution, and the searching ability is improved at first-half stage in the proposed GA processor. Then, the number of population is reduced by half, and the accuracy is improved at second-half stage. As a result, the searching ability is improved without increasing memory capacity. The proposed GA processor was designed by using VHDL and simulated. The effectiveness of proposed architecture was confirmed with examples.
Influence of van der Waals force on the pull-in parameters of cantilever type nanoscale electrostatic actuators
Authors: Asghar Ramezani, Aria Alasty, Javad Akbari
Venue: Microsystem Technologies (2006)

In this paper, the influence of the van der Waals force on two main parameters describing an instability point of cantilever type nanomechanical switches, which are the pull-in voltage and deflection are investigated by using a distributed parameter model. The fringing field effect is also taken into account. The nonlinear differential equation of the model is transformed into the integral form by using the Green&#x2019;s function of the cantilever beam. The integral equation is solved analytically by assuming an appropriate shape function for the beam deflection. The detachment length and the minimum initial gap of the cantilever type switches are given, which are the basic design parameters for NEMS switches. The pull-in parameters of micromechanical electrostatic actuators are also investigated as a special case of our study by neglecting the van der Waals force.
Virtual Lab for fMRI: Bridging the Usability Gap
Authors: Silvia D. Olabarriaga, Piter T. de Boer, Ketan Maheshwari, Adam Belloum, Jeroen G. Snel, Aart J. Nederveen, Maurice Bouwhuis
Venue: Proceedings of the Second IEEE International Conference on e-Science and Grid Computing (2006)

Grid technology can offer a powerful infrastructure for a broad spectrum of (scientific) application areas, but the uptake of grids by "real' applications has been slow. Several aspects contribute to this scenario, among them a large gap between the communities that develop and use the technology. While grid developments focus mostly on functionality, usability issues are also very important for the endusers. In the VL-e project, one of the goals is to bridge this gap, bringing (existing) grid technology to end-users in various application domains. This paper describes the current attempts to provide an IT infrastructure to facilitate neuroimaging research, in particular functional Magnetic Resonance Imaging (fMRI), which enables the study of brain function. The infrastructure offers resources for fMRI data acquisition, data storage, computing and services. All (local and grid) resources are accessed directly by the users from a virtual desktop implemented by a Virtual Resource Browser (VBrowser).
Asymptotic performance of second order blind separation
Authors: K. Abed-Meraim, A. Belouchrani, J. F. Cardoso, E. Moulines
Venue: Proceedings of the Acoustics, Speech, and Signal Processing,1994. on IEEE International Conference - Volume 04 (1994)

The article deals with the problem of blind separation of an instantaneous linear mixture of mutually uncorrelated sources. A solution based on the joint diagonalisation of a set of whitened correlation matrices has been proposed, along with an efficient algorithm to solve it. A second order source separation technique exploiting the time coherence of the source signals is considered. Asymptotic performance analysis of the proposed method is performed. Several numerical simulations are presented to demonstrate the effectiveness of the proposed method and to validate the theoretical expression of the asymptotic performance index.
On the complexity of scheduling in wireless networks
Authors: Gaurav Sharma, Ravi R. Mazumdar, Ness B. Shroff
Venue: Proceedings of the 12th annual international conference on Mobile computing and networking (2006)

We consider the problem of throughput-optimal scheduling in wireless networks subject to interference constraints. We model the interference using a family of K -hop interference models. We define a K-hop interference model as one for which no two links within K hops can successfully transmit at the same time (Note that IEEE 802.11 DCF corresponds to a 2-hop interference model.) .For a given K, a throughput-optimal scheduler needs to solve a maximum weighted matching problem subject to the K-hop interference constraints. For K=1, the resulting problem is the classical Maximum Weighted Matching problem, that can be solved in polynomial time. However, we show that for K>1,the resulting problems are NP-Hard and cannot be approximated within a factor that grows polynomially with the number of nodes. Interestingly, we show that for specific kinds of graphs, that can be used to model the underlying connectivity graph of a wide range of wireless networks, the resulting problems admit polynomial time approximation schemes. We also show that a simple greedy matching algorithm provides a constant factor approximation to the scheduling problem for all K in this case. We then show that under a setting with single-hop traffic and no rate control, the maximal scheduling policy considered in recent related works can achieve a constant fraction of the capacity region for networks whose connectivity graph can be represented using one of the above classes of graphs. These results are encouraging as they suggest that one can develop distributed algorithms to achieve near optimal throughput in case of a wide range of wireless networks.
Recursive Bayes risk parameter estimation from the cyclic autocorrelation matrix
Authors: J. Riba-Sagarra, G. Vazquez-Grau
Venue: Proceedings of the Acoustics, Speech, and Signal Processing,1994. on IEEE International Conference - Volume 04 (1994)

We present a new method for recursively estimating the frequency and timing parameters of a second order cyclostationary signal with known cyclic autocorrelation matrix (CAM). This problem appears in the context of radar as well as asynchronous communications in highly non-stationary environments (e.g. telemetry) due to the Doppler effect. The parameters evolution is modelled by a zero-order random walk. The estimates are obtained from the instantaneous CAM (ICAM) of the signal. While nonlinear Kalman filter theory is a possible approach to this problem, Bayes risk theory is used instead. In this way the Riccati equation and gain matrices become independent of the estimates, thus allowing a look-up table solution. The folded normal density (FND) is assumed as parameters' prior. The prior is recursively updated in mean (estimates) and variance. By comparing the obtained equations with linear Kalman filter equations we show that with few modifications a first-order random walk model can be easily incorporated to cope with highly non-stationary frequency evolution.
Light-weight leases for storage-centric coordination
Authors: Gregory Chockler, Dahlia Malkhi
Venue: International Journal of Parallel Programming (2006)

Reaching agreement among processes sharing read/write memory is possible only in the presence of an eventual unique leader. A leader that fails must be recoverable, but on the other hand, a live and well-performing leader should never be decrowned. This paper presents the first leader algorithm in shared memory environments that guarantees an eventual leader following global stabilization time. The construction is built using light-weight lease and renew primitives. The implementation is simple, yet efficient. It is uniform, in the sense that the number of potentially contending processes for leadership is not a priori known.
Enterprise Integration with Ruby
Authors: Steve Vinoski
Venue: IEEE Internet Computing (2006)

If you need to glue together multiple technologies, such as databases, Lightweight Directory AccessProtocol (LDAP), XML, messaging, Remote Procedure Calls (RPCs), and distributed objects, the Rubyprogramming language might be the answer to help you do it.
Specification and Verification of Dynamic Communication Systems
Authors: Jorg Bauer, Ina Schaefer, Tobe Toben, Bernd Westphal
Venue: Proceedings of the Sixth International Conference on Application of Concurrency to System Design (2006)

Dynamic communication systems (DCS) are complex because of their unboundedness in several dimensions. They have an unbounded and changing number of objects, a dynamically changing communication topology and unbounded message queues for asynchronous communication. We present a specification language for DCS that captures these features but is still amenable for formal verification. The verification of relevant properties of DCS is demonstrated using a combination of model-checking and abstract interpretation. Our approach is illustrated using the application domain of car platoons.
Non-quadratic convex regularized reconstruction of MR images from spiral acquisitions
Authors: R. Boubertakh, J.-F. Giovannelli, A. De Cesare, A. Herment
Venue: Signal Processing (2006)

Combining fast MR acquisition sequences and high resolution imaging is a major issue in dynamic imaging. Reducing the acquisition time can be achieved by using non-Cartesian and sparse acquisitions. The reconstruction of MR images from these measurements is generally carried out using gridding that interpolates the missing data to obtain a dense Cartesian k-space filling. The MR image is then reconstructed using a conventional fast Fourier transform (FFT). The estimation of the missing data unavoidably introduces artifacts in the image that remain difficult to quantify.A general reconstruction method is proposed to take into account these limitations. It can be applied to any sampling trajectory in k-space, Cartesian or not, and specifically takes into account the exact location of the measured data, without making any interpolation of the missing data in k-space. Information about the expected characteristics of the imaged object is introduced to preserve the spatial resolution and improve the signal-to-noise ratio in a regularization framework. The reconstructed image is obtained by minimizing a non-quadratic convex objective function. An original rewriting of this criterion is shown to strongly improve the reconstruction efficiency. Results on simulated data and on a real spiral acquisition are presented and discussed.
Image registration, color correction, and change detection based on value of difference in sequential ocular fundus images
Authors: Satoshi Sakuma, Tadashi Nakanishi, Yasuko Takahashi, Yuichi Fujino, Sakuichi Ohtsuka, Akira Tomono, Norimasa Nakanishi, Tetsuro Tsubouchi, Tsuyoshi Tanino
Venue: Systems and Computers in Japan (2006)

The purpose of this study is to assist ophthalmologic screening in health checks. A decision process for detecting progressive change is proposed in which normal cases are rejected on the basis of comparison between the ocular fundus image to be examined and the normal ocular fundus image of the same subject. Ocular fundus images contain large individual differences, but there is no progressive change in the normal condition. A large change in the image is observed only when there is a pathological change, such as white spots or hemorrhage. Consequently, an automatic screening procedure is considered in which an ocular fundus image diagnosed as normal is prepared for each individual, and images are judged to be normal when no progressive change is indicated by the difference between images. Specifically, an algorithm which consists of the following procedures is created. Image registration is applied, considering the ocular fundus shape of the individual. Color correction is applied to correct the brightness and color difference due to imaging conditions. The images are compared and the difference between the images is calculated and the presence or absence of progressive changes is decided. The algorithm was evaluated by using real ocular fundus images, and a rejection rate of 78&percnt; for normal cases was obtained. Thus, it is possible to assist screening by providing a pathological index. &copy; 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(11): 100&ndash;112, 2006; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.10170
The importance of sibling clustering for efficient bulkload of XML document trees
Authors: C. C. Kanne, G. Moerkotte
Venue: IBM Systems Journal (2006)

In an XML Data Store (XDS), importing documents from external sources is a very frequent operation. Because a document import consists of a large number of individual node inserts, it is essentially a small bulkload operation, and thus efficient bulkload support is crucial for the performance of the XDS. The bulkload operation is in essence a mapping of an XML parser's output into the storage structures of the XDS. This involves two major subtasks: (1) partitioning the document's logical tree structure into subtrees that can be stored on a page in a way that is both space-efficient and suitable for later processing and (2) mapping the subtrees to the internal representation of the XDS for paging. In enterprise-scale environments with very large documents and many parallel bulkload operations, the first task is particularly challenging, as not only disk space consumption, but also CPU and main-memory usage are important factors. In this paper, we discuss the requirements for an XDS bulkload component and examine existing algorithms for tree partitioning and their applicability to the bulkload operation. We derive a new tree-partitioning algorithm for use in the bulkload operation and present the design of the bulkload component for the XDS Natix. Finally, we evaluate the performance of the bulkload component and compare our results with previous work.
Fuzzy clustering of color and texture features for image segmentation: a study on satellite image retrieval
Authors: W. S. Ooi, C. P. Lim
Venue: Journal of Intelligent Fuzzy Systems: Applications in Engineering and Technology (2006)

In this paper, a new image segmentation approach that integrates color and texture features using the fuzzy c-means clustering algorithm is described. To demonstrate the applicability of the proposed approach to satellite image retrieval, an interactive region-based image query system is designed and developed. A database comprising 400 multispectral satellite images is used to evaluate the performance of the system. The results are analyzed and discussed, and a performance comparison with other methods is included. The outcomes reveal that the proposed approach is able to improve the quality of the segmentation results as well as the retrieval performance.
On multi-symplectic partitioned Runge-Kutta methods for Hamiltonian wave equations
Authors: Qinghong Li, Yongzhong Song, Yushun Wang
Venue: Applied Mathematics and Computation (2006)

Many conservative PDEs, such as various wave equations, Schrödinger equations, KdV equations and so on, allow for a multi-symplectic formulation which can be viewed as a generalization of the symplectic structure of Hamiltonian ODEs. In this note, we show the discretization to Hamiltonian wave equations in space and time using two symplectic partitioned Runge-Kutta methods respectively leads to multi-symplectic integrators which preserve a symplectic conservation law. Under some conditions, we discuss the energy and momentum conservative property of partitioned Runge-Kutta methods for the wave equations with a quadratic potential.
Abnormal Auditory Cortical Activation in Dyslexia 100 msec after Speech Onset
Authors: Päivi Helenius, Riitta Salmelin, Ulla Richardson, Seija Leinonen, Heikki Lyytinen
Venue: Journal of Cognitive Neuroscience (2002)

Reading difficulties are associated with problems in processing and manipulating speech sounds. Dyslexic individuals seem to have, for instance, difficulties in perceiving the length and identity of consonants. Using magnetoencephalography (MEG), we characterized the spatio-temporal pattern of auditory cortical activation in dyslexia evoked by three types of natural bisyllabic pseudowords (/ata/, /atta/, and /a a/), complex nonspeech sound pairs (corresponding to /atta/ and /a a/) and simple 1-kHz tones. The most robust difference between dyslexic and non-reading-impaired adults was seen in the left supratemporal auditory cortex 100 msec after the onset of the vowel /a/. This N100m response was abnormally strong in dyslexic individuals. For the complex nonspeech sounds and tone, the N100m response amplitudes were similar in dyslexic and nonimpaired individuals. The responses evoked by syllable /ta/ of the pseudoword /atta/ also showed modest latency differences between the two subject groups. The responses evoked by the corresponding nonspeech sounds did not differ between the two subject groups. Further, when the initial formant transition, that is, the consonant, was removed from the syllable /ta/, the N100m latency was normal in dyslexic individuals. Thus, it appears that dyslexia is reflected as abnormal activation of the auditory cortex already 100 msec after speech onset, manifested as abnormal response strengths for natural speech and as delays for speech sounds containing rapid frequency transition. These differences between the dyslexic and nonimpaired individuals also imply that the N100m response codes stimulus-specific features likely to be critical for speech perception. Which features of speech (or nonspeech stimuli) are critical in eliciting the abnormally strong N100m response in dyslexic individuals should be resolved in future studies.
Searching Similar Modules in Protein Interaction Netwo
Authors: Hiroyuki Oka, Masanori Arita
Venue: Proceedings of the 21st International Conference on Data Engineering Workshops (2005)

We developed a new method to search protein networks functionally similar to a given query signal transduction pathway within protein interaction networks. This method consists of two parts: 1) a backtracking search algorithm to find topologically identical subgraphs and 2) a measurement of similarity between proteins by using Gene Ontology [1]. For validation of our method, we implemented a software tool and compared its performance with that of PathBLAST [2] on the search of MAPK signal transduction cascades [3]. The result showed that our software tool has equal or better performance than that of PathBLAST.
Evaluation of user satisfaction and learnability for outdoor augmented reality gaming
Authors: Benjamin Avery, Wayne Piekarski, James Warren, Bruce H. Thomas
Venue: Proceedings of the 7th Australasian User interface conference - Volume 50 (2006)

We have developed an outdoor augmented reality game, Sky Invaders 3D, which is designed to be played by the game playing public. We conducted a user study to measure how much users enjoyed playing an outdoor AR game, and how intuitive it was. We compared 44 participants on one of two games, an outdoor AR game, or a desktop PC equivalent of the same game. We found the AR game was rated by the participants as significantly more enjoyable by the users and more intuitive to use.