ppxscal/embedding_network huggingface dataset:
Modelling international tourism demand and uncertainty in Maldives and Seychelles: A portfolio approach
Authors: Riaz Shareef, Michael McAleer
Venue: Mathematics and Computers in Simulation (2008)

Maldives and Seychelles in the Indian Ocean are small island tourism economies (SITEs), both of which have relatively small populations, territorial sizes, land area and narrow productive bases. The two SITEs are surrounded by vast ocean and have an overwhelming reliance on international tourism for economic development. Variations in international tourist arrivals to these two SITEs have been affected by unanticipated oil shocks, natural disasters, crime and global terrorism, among others. An accurate assessment of the variations in international tourist arrivals, particularly the conditional volatility, is essential for policy and marketing purposes. The conditional mean and conditional variance of the weekly international tourist arrivals to Maldives and Seychelles from 1 January 1994 to 31 December 2003 for the five main tourist source countries are modelled. Multivariate models of uncertainty are estimated and tested. An assessment and interpretation of the estimates are made for policy makers and tour operators to reach optimal decisions on the basis of a portfolio approach to international tourism demand. The paper assesses four sets of country spillover effects between Maldives and Seychelles, namely (i) the own country effects for Maldives and Seychelles; (ii) the country spillover effects from the remaining four countries within each of Maldives and Seychelles; (iii) the own country spillover effects between Maldives and Seychelles; and (iv) the cross-country spillover effects between Maldives and Seychelles. The empirical results for both Maldives and Seychelles are discussed in terms of each of these components.
Silicon on nothing MEMS electromechanical resonator
Authors: C&#x00e9;dric Durand, Fabrice Casset, Pascal Ancey, Fabienne Judong, Alexandre Talbot, R&#x00e9;mi Quenouill&#x00e8;re, Denis Renaud, St&#x00e9;phan Borel, Brigitte Florin, Lionel Buchaillot
Venue: Microsystem Technologies (2008)

The very significant growth of the wireless communication industry has spawned tremendous interest in the development of high performance radio frequencies (RF) components. Micro electro mechanical systems (MEMS) are good candidates to allow reconfigurable RF functions such as filters, oscillators or antennas. This paper will focus on the MEMS electromechanical resonators, which show interesting performances to replace surface acoustic waves (SAW) filters or quartz reference oscillators, allowing smaller integrated functions with lower power consumption. The resonant frequency depends on the material properties, such as Young&#x2019;s modulus and density, and on the movable mechanical structure dimensions (beam length defined by photolithography). Thus, it is possible to obtain multi frequencies resonators on a wafer. The resonator performance (frequency, quality factor) strongly depends on the environment, like moisture or pressure, which imply the need for a vacuum package. This paper will present first resonator mechanisms and mechanical behaviors followed by state of the art descriptions with applications and specifications overview. Then MEMS resonator developments at STMicroelectronics including FEM analysis, technological developments and characterization are detailed.
Variable causality dynamics system approach for robot control
Authors: Anca Petrisor, Constantin Marin, Nicu George Bîzdoaca, Dumitru Cazacu
Venue: Proceedings of the 5th WSEAS International Conference on Computational Intelligence, Man-Machine Systems and Cybernetics (2006)

The paper presents the mathematical model of a walking robot controlled by a shoulder position and its joining angle. It is considered that first leg angles from the active pair of legs are both external controlled and second leg has the knee joint free and the shoulder joint external controlled. The mathematical model is determined considering all the points in the xz-plane as being complex numbers. Taking into account a possible symmetrical structure, only the vertical xz-plane evolution is considered. The model is based on the so called Variable Causality Dynamic Systems (VCDS) approach. In this causality ordering, the whole structure is controlled in open circuit or in manual operating conditions. The results of this paper are implemented and verified in RoPa, a platform for simulation and design of walking robots control algorithms. The model is implemented in MATLAB environment and some evolutions examples are presented.
Discrete-Event System Simulation for Information Quality Assurance
Authors: Ying Su, Zhanming Jin, Jie Peng
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

The objective of this paper is to propose an intelligent information quality assurance (IQA) system using Configurable Event-Driven Process Chain (C-EPC) simulation based analysis, which is capable to monitor network status, evaluate IQ, generate assuring strategies, and apply it to the network. To do this, we have employed the C-EPC formalism concept based on the advanced modeling and simulation environment for developing information security models and simulation-based evaluation of IQ as well as assuring strategy. Our approach differs from others in that a) it is able to analyze IQ on node, link, and network in quantitative manner, b) it can generate and apply assuring strategies automatically, and c) it supports a coherent design concept for intelligent IQA system. A case study performed on a test bed will illustrate our techniques and demonstrate effectiveness of propose system.
High-Speed and Power Efficient Lifting-Based VLSI Architecture for Two-Dimesional Discrete Wavelet Transform
Authors: Ibrahim Saeed, Herman Agustiawan
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

Two lifting-based VLSI architectures for 2-DDWT for lossless 5/3 and lossy 9/7 algorithms were proposedby Ibrahim et al., based on two scan methods, overlapped and nonoverlaped. In the architecture based on the overlapped scan method, the maximum power consumption occurs due to overlap external frame memory access. On the other hand, in the nonoverlapped architecture, the power consumption was reduced to minimum by eliminating the overlapped areas which requires the addition of a line buffer of size N. Furthermore, the performance evaluations by Ibrahim el at., show that those pipelined architectures are optimal in terms of speedup, efficiency and hardware utilization. In this paper, we proposed new architecture, called intermediate architecture, for both 5/3 and 9/7algorithms, which aim at reducing the power consumption of the overlapped areas, without using the expensive linebuffer, to somewhat between the two extreme architectures proposed by Ibrahim et al.
Democratic approximation of lexicographic preference models
Authors: Fusun Yaman, Thomas J. Walsh, Michael L. Littman, Marie desJardins
Venue: Proceedings of the 25th international conference on Machine learning (2008)

Previous algorithms for learning lexicographic preference models (LPMs) produce a "best guess" LPM that is consistent with the observations. Our approach is more democratic: we do not commit to a single LPM. Instead, we approximate the target using the votes of a collection of consistent LPMs. We present two variations of this method---variable voting and model voting---and empirically show that these democratic algorithms outperform the existing methods. We also introduce an intuitive yet powerful learning bias to prune some of the possible LPMs. We demonstrate how this learning bias can be used with variable and model voting and show that the learning bias improves the learning curve significantly, especially when the number of observations is small.
Securing dynamic itineraries for mobile agent applications
Authors: Carles Garrigues, Sergi Robles, Joan Borrell
Venue: Journal of Network and Computer Applications (2008)

In this paper we present a novel mechanism for the protection of dynamic itineraries for mobile agent applications. Itineraries that are decided as the agent goes are essential in complex applications based on mobile agents, but no approach has been presented until now to protect them. We have conceived a cryptographic scheme for shielding dynamic itineraries from tampering, impersonation and disclosure. By using trust strategically, our scheme provides a balanced trade-off between flexibility and security. Our protection scheme has been thought always bearing in mind a feasible implementation, and thus facilitates the development of applications that make use of it. An example application based on a real healthcare scenario is also presented to show its operation.
Convex recolorings of strings and trees: Definitions, hardness results and algorithms
Authors: Shlomo Moran, Sagi Snir
Venue: Journal of Computer and System Sciences (2008)

A coloring of a tree is convex if the vertices that pertain to any color induce a connected subtree; a partial coloring (which assigns colors to some of the vertices) is convex if it can be completed to a convex (total) coloring. Convex colorings of trees arise in areas such as phylogenetics, linguistics, etc., e.g., a perfect phylogenetic tree is one in which the states of each character induce a convex coloring of the tree. When a coloring of a tree is not convex, it is desirable to know ''how far'' it is from a convex one, and what are the convex colorings which are ''closest'' to it. In this paper we study a natural definition of this distance-the recoloring distance, which is the minimal number of color changes at the vertices needed to make the coloring convex. We show that finding this distance is NP-hard even for a colored string (a path), and for some other interesting variants of the problem. In the positive side, we present algorithms for computing the recoloring distance under some natural generalizations of this concept: the first generalization is the uniform weighted model, where each vertex has a weight which is the cost of changing its color. The other is the non-uniform model, in which the cost of coloring a vertex v by a color d is an arbitrary non-negative number cost(v,d). Our first algorithms find optimal convex recolorings of strings and bounded degree trees under the non-uniform model in time which, for any fixed number of colors, is linear in the input size. Next we improve these algorithm for the uniform model to run in time which is linear in the input size for a fixed number of bad colors, which are colors which violate convexity in some natural sense. Finally, we generalize the above result to hold for trees of unbounded degree.
Validation of MERIS reflectance and chlorophyll during the BENCAL cruise October 2002: preliminary validation of new demonstration products for phytoplankton functional types and photosynthetic parameters
Authors: J. Aiken, J. R. Fishwick, S. Lavender, R. Barlow, G. F. Moore, H. Sessions, S. Bernard, J. Ras, N. J. Hardman-Mountford
Venue: International Journal of Remote Sensing (2007)

We measured water leaving reflectance, phytoplankton pigments, optical properties and photosynthetic parameters in the southern Benguela ecosystem in October 2002. These data were used to validate MERIS standard products: reflectance (MERIS wavelengths) and Case 1 Chlorophyll-a. In this heterogeneous area, accurate validation required sampling within a few minutes of the satellite overpass. Inter-pigment relationships e.g. Total Chlorophyll (TChla) to Total Pigment (TP) were robust (R2∼0.99) yet pigment ratios (TChla/TP) were not constant (range 0.44 to 0.62) increasing log-linearly with biomass (R2∼0.7). Photosynthetic parameters (e.g. Photosynthetic Quantum Efficiency, PQE) and optical ratios (a676/a440) also increased log-linearly with biomass (R2∼0.8). PQE, pigment and optical ratios were linearly inter-correlated (R2∼0.7 to 0.8). From these data we derived the bio-optical traits for several phytoplankton functional types (PFTs): micro-plankton (diatoms and dinoflagellates) had high biomass, pigment ratios and PQE; nano-flagellates had low to intermediate biomass, pigment ratios and PQE; prokaryotes had very low biomass, pigment ratios and PQE. We present MERIS data analysed for PFTs and new products (PQE).
Patterning a nanowell sensor biochip for specific and rapid detection of bacteria
Authors: Sungkyu Seo, Maria Dobozi-King, Ryland F. Young, Laszlo B. Kish, Mosong Cheng
Venue: Microelectronic Engineering (2008)

This paper presents the fabrication process of a SEPTIC (SEnsing of Phage-Triggered Ion Cascades) chip, consisting of two Ti contact pads and a 150nm wide Ti nanowell device on LiNbO"3 substrate. The patterning was fulfilled by combining electron beam lithography, contact photolithography and reactive ion etching. When connected to an external preamplifier and spectrum analyzer, the nanowell can probe nano-scale electric field fluctuations. The use of this chip as nano-scale electric field probe was demonstrated by detecting the transitory ion efflux from bacteria being infected by phage. Our experiment showed that the electric field noise follows 1/f^2 power spectrum when the bacteria are sensitive to the phage, whereas 1/f noise corresponds to bacteria resistant to the phage. The use of fluctuation-enhanced sensing can provide sensitivity orders of magnitude higher than conventional sensing that detects changes only in the mean value of electrical signals.
Signal Classification Based on Spectral Correlation Analysis and SVM in Cognitive Radio
Authors: Hao Hu, Yujing Wang, Junde Song
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

Spectrum sensing is one of the most challenging functions in cognitive radio system. Detection of the presence of signals and distinction of the type of signals in a particular frequency band are critical for cognitive radios to adapt to the radio environment. In this paper, a novel approach to signal classification combining spectral correlation analysis and support vector machine (SVM) is introduced. Four spectral coherence characteristic parameters are chosen via spectral correlation analysis. By utilizing a nonlinear SVM, a significant amount of calculation is performed offline, thus the computational complexity is reduced. Simulations indicate that the overall success rate is above 92.8% with data length of 1000 when SNR is equal to 4 dB. Compared to the existing methods including the classifiers based on binary decision tree (BDT) and multilayer linear perceptron network (MLPN), the proposed approach is more effective in the case of low SNR and limited training numbers.
Improved state estimation of stochastic systems
Authors: Nicholas A. Nechval, Gundars Berzins, Maris Purgailis, Konstantin N. Nechval
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

In the present paper, for constructing the minimum risk estimators of state of stochastic systems, a new technique of invariant embedding of sample statistics in a loss function is proposed. This technique represents a simple and computationally attractive statistical method based on the constructive use of the invariance principle in mathematical statistics. Unlike the Bayesian approach, an invariant embedding technique is independent of the choice of priors. It allows one to eliminate unknown parameters from the problem and to find the best invariant estimator, which has smaller risk than any of the well-known estimators. Also the problem of how to select the total number of the observations optimally when a constant cost is incurred for each observation taken is discussed. To illustrate the proposed technique, an example is given.
Towards Computational Models for Mobile Learning Objects
Authors: Gerardo Ayala, Sergio Castillo
Venue: Proceedings of the Fifth IEEE International Conference on Wireless, Mobile, and Ubiquitous Technology in Education (2008)

Mobile learning objects must not be designed and developed as learning objects for personal computers, becoming just an adaptation to the restrictions of the interface of mobile devices. They should be designed, developed and used taking into consideration the advantages of mobile devices and the learning approaches that support mobile learning environments. In this paper we introduce a set of computational models for mobile learning objects. Our proposal consists of a personalization model, a collaboration model and an interaction model. These models are based on situated, collaborative and personalized learning, and support the context awareness, knowledge awareness and social awareness required for the effective use of learning objects in a mobile learning environment.
Natural interaction in intelligent spaces: Designing for architecture and entertainment
Authors: Flavia Sparacino
Venue: Multimedia Tools and Applications (2008)

The rapid evolution of computers' processing power, progress in projection and display technology, and their low cost, accompanied by recent advances in mathematical modeling, make available to space designers today sophisticated technologies which were once accessible only to research institutions or large companies. Thanks to wireless sensing techniques it is possible to endow a space with perceptual intelligence, and make it aware of how people use it, move in it, or react to it. Intelligent Spaces are relevant for several applications or tasks which range from surveillance to entertainment, from medical rehabilitation to artistic performance, from museum exhibit design to commerce. The author's work focuses on Narrative Spaces which are storytellers, able to articulate an informative or entertaining audio-visual narration for people interactively. Narrative Spaces communicate by use of large scale coordinated projections, sounds and displays whose contents are choreographed by the natural body movements or physical gestures of the people in them. This paper describes the guiding principles and modeling approaches that, according to the author, enable a robust modeling of user input and communication strategies for digital content presentation in Intelligent Narrative Spaces. It then provides examples of applications built according to the specified criteria.
Ad-hoc co-located collaborative work with mobile devices
Authors: Kris Luyten, Kristof Verpoorten, Karin Coninx
Venue: Proceedings of the 9th international conference on Human computer interaction with mobile devices and services (2007)

This paper presents how ad-hoc co-located collaborations can be supported with an arbitrary number of users that only have access to small-size mobile displays. Our approach is based on tracking of these personal displays that share the same information space. All displays involved in the collaboration act as autonomous windows on a set of data items (the information space) positioned on a shared virtual canvas. Data items are identified by their three-dimensional location in physical space and can be manipulated through the displays that serve as windows on the shared canvas. Each display is tracked in physical space and is aware of its own location. Since different mobile displays can access and manipulate the same information space, a distributed locking mechanism makes sure the data stays consistent during simultaneous access of data in this information space.
Amplifying Embedded System Efficiency via Automatic Instruction Fusion on a Post-Manufacturing Reconfigurable Architecture Platform
Authors: Allen C. Cheng
Venue: Proceedings of the 9th international symposium on Quality Electronic Design (2008)

Portable embedded SoC processor architects are constantly challenged by exponentially increasing demand for newer functionality, faster real-time communication, stronger security, and higher reliability; while the constraint on energy, feature size, NRE cost, and time-to-market (TTM) grows tighter than ever. Existing approaches attempting to achieve these mutual conflicting design goals rely heavily on adopting special-purpose accelerators (SPA) to take charge of the heavy lifting in the aimed embedded SoC designs. These SPAs, synthesized from either ASIC or FPGA, are usually augmented to the base processor as co-processors to execute the performance-critical regions of applications. ASIC-based SPAs achieve performance-energy efficiency at the expense of sacrificing post-manufacturing programmability while incurring large NRE and TTM; FPGA-based SPAs retain programmability at the expense of significant energy and area increase. Furthermore, augmenting these SPAs as co-processors adds considerable communication and synchronization overhead severely com-promising their initially promised benefits. This paper proposes an innovative design paradigm that moves away from the common scheme of adding co-processing ASIC/FPGA SPAs to an integrated and reconfigurable design. Specifically, we propose a new class of embedded processor by replacing the processor’s conventional ALU with a more powerful and flexible Versatile Processing Unit (VPU). VPU enables multiple interdependent instructions to be fused and processed together as a single atomic VPU instruction by exploring dataflow dependencies of the application code. The instruction fusion is automatically performed by a VPU-aware compiler. The optimized VPU code reduces code size and amplifies the effective processor bandwidth and capacity by eliminating transient computation and register spill code. Experimental results show up to 400% and average 150% speedup for MediaBench with negligible area increase.
A Scalable Approach for Application Layer Multicast in P2P Networks
Authors: Amad Mourad, Meddahi Ahmed
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

Application layer multicast (ALM) is considered as an attractive approach for implementing wide area multicast services. In ALM, multicast functionality is implemented at the edge instead of the core network (routers). As opposed to network-layer multicast, application layer multicast requires no infrastructure support and can be easily deployed in the Internet. In this paper, we propose a new generic and scalable approach for optimizing application layer multicast in the context of Peer-to-Peer networks (structured and unstructured). This approach benefits from P2P properties and characteristics. In this contribution, we consider two approaches for multicast tree construction: a primitive” approach, and an optimized one based on a distributed algorithm. The proposed protocol inherits from main P2P attributes such as: scalability, fault tolerance. Performance evaluation shows that results are globally satisfactory compared to the main existing application layer multicast protocols.
Distributed Video Adaptation and Streaming for Heterogeneous Devices
Authors: Razib Iqbal, Dewan Tanvir Ahmed, Shervin Shirmohammadi
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

In this paper, we present a new concept of distributed adaptation and P2P streaming supporting the expansion of context-aware mobile P2P systems. Here, we propose to adapt video contents in a distributed manner to address the peer heterogeneity. It also forms an overlay network and organizes video streaming sessions among the participating peers. We have followed a master-sender-driven approach (one-to-many), with the help of cooperative peers. The essential incentive behind this work is that with the modern computing capabilities, a single peer can carry out sufficient adaptation operations and stream media contents to other peers. Overall design and adaptation approach along with the performance evaluation is presented in brief.