ppxscal/embedding_network huggingface dataset:
Complex-field network coding in high-throughput anti-jam wireless networks
Authors: Georgios B. Giannakis
Venue:  (2008)

Network coding in wired networks has been shown to achieve considerable throughput gains relative to traditional routing networks. In wireless networks, Galois-field network coding (GFNC) has been explored over the last years. However, the throughput of GFNC-based networks does not scale well as the number of sources increases, which motivates the complex field network coding (CFNC) approach in this thesis. CFNC achieves higher throughput than GFNC in a multi-source network while enabling the full diversity gain provided by the distributed multi-input multi-output (MIMO) channel regardless of the underlying signal-to-noise-ratio (SNR) and the constellation used. A link-adaptive regeneration relaying strategy is also developed for CFNC to achieve full diversity with or without error control coding. With the help of a relay, CFNC also allows n nodes exchanging information with simultaneous transmissions from multiple sources in a wireless network. Although the ergodic capacity is unknown for wireless multihop networks, the scaling of capacity with the number of nodes (n) has recently received increasing attention. While existing works mainly focus on networks with n source-destination pairs, this thesis deals with capacity scaling in any-to-any wireless links, where each node communicates with all other nodes. As n increases, a hierarchical CFNC-based scheme is developed and shown to achieve asymptotically optimal quadratic capacity scaling in a dense network, where the area is fixed and the density of nodes increases. This is possible by dividing the network into many clusters, with each cluster sub-divided into many sub-clusters, hierarchically. As a result, information is transmitted on MIMO based multiple access channels and broadcast channels. When generalized to extended networks, where the density of nodes is fixed and the area increases linearly with n, the hierarchical CFNC scheme is shown to scale as n 3&ndash;&alpha;/2 for a path loss exponent &alpha; &ge; 2, which is asymptotically optimal when &alpha; < 3. While a relay node improves the throughput, a jammer node may be present to inhibit or halt the transmission of signals in a tactical (or commercial) wireless network. A two-person zero-sum mutual information game is considered between one jammer ( J ) and one relay ( R ), in both non-fading and fading scenarios.
The relationships among service quality, perceived value, customer satisfaction, and post-purchase intention in mobile value-added services
Authors: Ying-Feng Kuo, Chi-Ming Wu, Wei-Jaw Deng
Venue: Computers in Human Behavior (2009)

The purposes of this study are to construct an instrument to evaluate service quality of mobile value-added services and have a further discussion of the relationships among service quality, perceived value, customer satisfaction, and post-purchase intention. Structural equation modeling and multiple regression analysis were used to analyze the data collected from college and graduate students of 15 major universities in Taiwan. The main findings are as follows: (1) service quality positively influences both perceived value and customer satisfaction; (2) perceived value positively influences on both customer satisfaction and post-purchase intention; (3) customer satisfaction positively influences post-purchase intention; (4) service quality has an indirect positive influence on post-purchase intention through customer satisfaction or perceived value; (5) among the dimensions of service quality, ''customer service and system reliability'' is most influential on perceived value and customer satisfaction, and the influence of ''content quality'' ranks second; (6) the proposed model is proven with the effectiveness in explaining the relationships among service quality, perceived value, customer satisfaction, and post-purchase intention in mobile added-value services.
Distributed detection of node replication attacks resilient to many compromised nodes in wireless sensor networks
Authors: Yuichi Sei, Shinichi Honiden
Venue: Proceedings of the 4th Annual International Conference on Wireless Internet (2008)

In large-scale sensor networks, sensor nodes are at high risk of being captured and compromised. Once a sensor node is compromised, all the secret keys, data, and code stored on it are exposed to the attacker. The attacker can insert arbitrary malicious code in the compromised node. Moreover, he can easily replicate it in a large number of clones and deploy them on the network. This node replication attack can form the basis of a variety of attacks such as DoS attacks, and Sybil attacks. Previous studies of node replication attacks have had some drawbacks; they need a central trusted entity or they become vulnerable when many nodes are compromised. Therefore, we propose a distributed protocol for detecting node replication attacks that is resilient to many compromised nodes. Our method does not need any reliable entities and has a high detection rate of replicated nodes. Our analysis and simulations demonstrate our protocol is effective even when there are a large number of compromised nodes.
Errors in Structure Self-organization: Statistical Analysis
Authors: Grzegorz Kukla, Dariusz Król
Venue: Proceedings of the Third KES International Symposium on Agent and Multi-Agent Systems: Technologies and Applications (2009)

This paper contributes to the agent-based community by providing a better understanding of error propagation mechanisms in structure self-organization focusing especially on the statistical analysis of experiments. The research was verified based on the experiments conducted on simulation model. The results provide some ideas of robustness - the knowledge how to design the most error resistant architectures in complex environments. Additionally, well-known statistical tests are used to verify the hypothesis. Finally, open research issues with practical relevance are proposed.
Towards a new camera model for X3D
Authors: Yvonne Jung, Johannes Behr
Venue: Proceedings of the 14th International Conference on 3D Web Technology (2009)

Creating and setting the right parameters for the virtual camera is crucial for any content creation process. However, this is not easy since most current camera models, including the X3D Viewpoint, use a 3D position and orientation in 3D space to define the final visualized image. People use authoring tools or simple interactive navigation methods (e.g. "lookAt" or "showAll") to ease the process but at the end they still move a 6D (translation and rotation) camera beacon to get the final image. We thus propose a new X3D camera model, the CinematographicViewpoint node, which does not force the content creator to move the camera but allows the author to directly define what objects he would like to see on the screen. We borrow established techniques from the film area (e.g. rule of thirds and line of action) that allow defining objects and object-relations, which the camera model will use to automatically calculate the final transformation in space. The new camera model includes additionally a model for global visual effects (e.g. motion blur and depth of field), which allows incorporating classical film effects to real-time scenes. Both approaches combined allow content creators building visual results and camera movements that are closer to traditional filming much easier. The proposed approach also supports automatic camera movements that are bound to interactive content, which has not been possible before.
A unified shape editing framework based on tetrahedral control mesh
Authors: Yong Zhao, Xinguo Liu, Chunxia Xiao, Qunsheng Peng
Venue: Computer Animation and Virtual Worlds (2009)

It is a fundamental but challenging problem to efficiently edit complex 3D objects. By embedding the input models into coarse tetrahedral control meshes, this paper develops a unified framework to discuss two useful editing operations: interactive deformation and deformation transfer. First, a new rigidity energy is proposed to make the tetrahedral control mesh deform as rigidly as possible, which yields intuitive detail and volume preservation even under large deformations. And an error-driven refinement approach is presented to further improve the deformation result. Then, based on this deformation scheme, a volumetric correspondence method is introduced to perform the deformation transfer task between the tetrahedral control meshes of the source and target models, which greatly lessens the burden of the user. Experimental results show our algorithm is effective, easy to control, supports various shape representations, and well transfers deformations between non-homeomorphous models. Copyright &copy; 2009 John Wiley & Sons, Ltd. It is a fundamental but challenging problem to efficiently edit complex 3D objects. By embedding the input models into coarse tetrahedral control meshes, this paper develops a unified framework to discuss two useful editing operations: interactive deformation and deformation transfer. Experimental results show our algorithm is effective, easy to control, supports various shape representations, such as meshes, point clouds, models with multiple parts or non-manifold structures etc, and well transfers deformations between non-homeomorphous models.
Lepp-bisection algorithms, applications and mathematical properties
Authors: Maria-Cecilia Rivara
Venue: Applied Numerical Mathematics (2009)

Longest edge (nested) algorithms for triangulation refinement in two dimensions are able to produce hierarchies of quality and nested irregular triangulations as needed both for adaptive finite element methods and for multigrid methods for PDEs. In addition, right-triangle bintree triangulations are multiresolution algorithms used for terrain modeling and real time visualization of terrain applications. These algorithms are based on the properties of the consecutive bisection of a triangle by the median of the longest edge, and can be formulated in terms of the longest edge propagation path (Lepp) and terminal edge concepts, which implies the use of very local refinement operations over fully conforming meshes (where the intersection of pairs of neighbor triangles is either a common edge or a common vertex). In this paper we review the Lepp-bisection algorithms, their properties and applications. To the end we use recent simpler and stronger results on the complexity aspects of the bisection method and its geometrical properties. We discuss and analyze the computational costs of the algorithms. The generalization of the algorithms to 3-dimensions is also discussed. Applications of these methods are presented: for serial and parallel view dependent level of detail terrain rendering, and for the parallel refinement of tetrahedral meshes.
Qualitative behavior of mixing phenomena: the case of axisymmetric extensional flows
Authors: Adela Ionescu, Daniela Coman
Venue: Proceedings of the 10th WSEAS international conference on Mathematical methods, computational techniques and intelligent systems (2008)

The problems of flow kinematics are far from complete solving, even in our days. A modern theory recently appeared in this field: the mixing theory. Its mathematical methods and techniques developed the significant relation between turbulence and chaos. The turbulence is an important feature of dynamic systems with few freedom degrees, the so-called "far from equilibrium systems". These are widespread between the models of excitable media. Studying a mixing for a flow implies the analysis of successive stretching and folding phenomena for its particles, the influence of parameters and initial conditions. In the previous works [2,3,4], the study of the 3D non-periodic models exhibited a quite complicated behavior. In agreement with experiments [6], they involved some significant events - the so-called "rare events". The variation of parameters had a great influence on the length and surface deformations. The 2D (periodic) case was simpler, but significant events can issue for irrational values of the length and surface versors, therefore a comparison with 3D case would reveal new analytical and quantitative features. This paper brings into attention another 3D mixing flow model, namely the axisymmetric extensional flow [5]. There is performed a qualitative analysis of its behavior from the stretch efficiency standpoint, handling modern appliances of MAPLE11 soft [1]. The recorded data are used for further statistical analysis.
Broadcasting from multiple originators
Authors: Arthur L. Liestman, Dana Richards, Ladislav Stacho
Venue: Discrete Applied Mathematics (2009)

We begin an investigation of broadcasting from multiple originators, a variant of broadcasting in which any k vertices may be the originators of a message in a network of n vertices. The requirement is that the message be distributed to all n vertices in minimum time. A minimumk-originator broadcast graph is a graph on n vertices with the fewest edges such that any subset of k vertices can broadcast in minimum time. B"k(n) is the number of edges in such a graph. In this paper, we present asymptotic upper and lower bounds on B"k(n). We also present an exact result for the case when k>=n2. We also give an upper bound on the number of edges in a relaxed version of this problem in which one additional time unit is allowed for the broadcast.
A variant of Wiener&#x2019;s attack on RSA
Authors: Andrej Dujella
Venue: Computing (2009)

Wiener&#x2019;s attack is a well-known polynomial-time attack on a RSA cryptosystem with small secret decryption exponent d, which works if d&#x00a0;<&#x00a0;n 0.25, where n&#x00a0;=&#x00a0;pq is the modulus of the cryptosystem. Namely, in that case, d is the denominator of some convergent p m /q m of the continued fraction expansion of e/n, and therefore d can be computed efficiently from the public key (n, e). There are several extensions of Wiener&#x2019;s attack that allow the RSA cryptosystem to be broken when d is a few bits longer than n 0.25. They all have the run-time complexity (at least) O(D 2), where d&#x00a0;=&#x00a0;Dn 0.25. Here we propose a new variant of Wiener&#x2019;s attack, which uses results on Diophantine approximations of the form |&#x03b1; &#x2212; p/q| <&#x00a0; c/q 2, and &#x201c;meet-in-the-middle&#x201d; variant for testing the candidates (of the form rq m+1 +&#x00a0; sq m ) for the secret exponent. This decreases the run-time complexity of the attack to O(D log D) (with the space complexity O(D)).
An ASSL-generated architecture for autonomic systems
Authors: Emil Vassev, Serguei A. Mokhov
Venue: Proceedings of the 2nd Canadian Conference on Computer Science and Software Engineering (2009)

The Autonomic System Specification Language (ASSL) is an initiative for the development of autonomic systems where we approach the problem of formal specification, validation, and code generation of such systems within a framework. ASSL generates an operational Java application skeleton from any valid specification where a special hierarchical multi-granular architecture composed of singleton classes is imposed. This paper presents the architecture model for autonomic systems generated with ASSL. Here we present a generic class model and a generic object model for autonomic systems. In addition, experimental results are provided to conclude the paper.
Asymptotic optimal method for localisation of a target in wireless sensor networks
Authors: Jaechan Lim, Jinseok Lee
Venue: International Journal of Communication Networks and Distributed Systems (2009)

In this paper, we present a location estimation method based on received signal strength (RSS) measurement or observation equation. The practical maximum likelihood (ML) estimator is asymptotically optimal in the sense it is asymptotically minimum variance unbiased (MVU) estimator and efficient estimator. We apply ML method to locating a target using multiple measurements where especially, numerical method is required. We employ two types of 'initial guesses' based on least squares (LS) method before initiating the iterative ML method in this paper. We show the performances comparison of a number of methods to achieve the optimal solution. The practical problems our approach can be applied to are 'localising mobile phones using multiple base stations' or 'localising wireless sensors using multiple anchor sensor nodes', etc.
Experimental study on wireless multicast scalability using Merged Hybrid ARQ with staggered adaptive FEC
Authors: Shivesh Makharia, Dipankar Raychaudhuri, Mingquan Wu, Hang Liu, Dekai Li
Venue: Proceedings of the 2008 International Symposium on a World of Wireless, Mobile and Multimedia Networks (2008)

We report the design, implementation and evaluation of Merged Hybrid ARQ with staggered FEC (MHARQ) system for video multicast over wireless LANs. MHARQ combines the advantages of receiver-driven staggered FEC and hybrid ARQ schemes to compensate the large dynamic range of WLAN channels and to achieve high reliability, scalability and wireless bandwidth efficiency for video multicast. The FEC packets generated by a cross-packet FEC code are divided into multiple streams according to the pre-configured overhead and are transmitted in different multiple IP multicast groups. Certain FEC streams are delayed from the original video stream. The receivers dynamically join/leave the FEC multicast groups based on the channel conditions. For efficient utilization of WLAN bandwidth, FEC data for a multicast group would not be transmitted by the APs in wireless networks if no receiver joins this group. The time shift between the video stream and the FEC streams introduces temporal diversity and compensates for the client join delay and handoff interruption. In addition, when delayed FEC packets are not enough to recover the lost packets, the receivers can send a hybrid ARQ request to the video server. We design a channel estimation algorithm for a receiver to dynamically determine the delayed FEC multicast groups to join and/or send ARQ NACK to request for retransmission. Using the ORBIT radio grid testbed, we have investigated the performance of the proposed MHARQ system with various numbers of users per AP and different number of APs per video server. It is demonstrated via real system implementation on ORBIT that MHARQ improves wireless bandwidth efficiency and scalability for reliable video multicast, compared with existing reliable multicast schemes.
Coordinating Asynchronous and Open Distributed Systems under Semiring-Based Timing Constraints
Authors: Yue Yu, Shangping Ren, Carolyn Talcott
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

For asynchronous and open distributed systems, dynamicity, openness, and stringent quality of service requirements pose great challenges to model and develop such systems. The Actor-Role-Coordinator (ARC) model was previously proposed to address these challenges. The role concept in the model addresses the dynamicity and openness issues by providing abstractions of actor behaviors. In this paper, we focus on coordinating actors and roles through message manipulations based on event-based timing constraints. In addition, different types of timing constraints are generalized into a semiring-based constraint structure; and the all-pairs extremal paths algorithm on closed semirings is applied to derive the most stringent constraints which are logical implications of the original set of constraints. The derived implicit constraints are further used to test constraint inclusions and decide intersections between feasible regions of timing constraint sets. The integration of the ARC model and the semiring-based timing constraint models is prototyped using Maude, a rewriting logic language. We further use the proposed approach to solve the Restaurant for Dining Philosophers problem and illustrate the expressiveness of the ARC and the semiring-based timing constraint models for exogenous and composable coordination of open systems.
XOR based LSB watermarking for information protection in land consolidation project
Authors: Li Li, Chao Zhang, Xinyu Li, Daoliang Li
Venue: Proceedings of the 13th WSEAS international conference on Applied mathematics (2008)

Land consolidation plays an important role in enlarging farming plots and enhancing crop productivity. And remote sensing imagery can provide the spatial data/maps and offer great advantages for the fulfillment of a land consolidation project. This paper presents a LSB watermarking algorithm to embed the land reorganization planning map into a remote sensing image of the same area for information security and copyright protection. The land reorganization planning map is compressively encoded before embedded into the protected remote sensing image. The contradiction between large information quantity and invisibility of digital water marking is perfectly eliminated. To avoid the shortcoming of being easily attacked in the original LSB method, the host image is preprocessed by exclusive-OR (XOR) operation. That is, the value of the least signification bit is decided by the XOR result of the first seven bits. The watermark signal is embedded into the LSB of the processed host image by XOR operation. The experimental results fully illustrate that the embedded watermark is not only imperceptible to the human eyes, but also has better security in the statistical sense.
An analysis of the length of hospital stay for cataract patients in Japan using the discrete-type proportional hazard model
Authors: Kazumitsu Nawata, Masako Ii, Aya Ishiguro, Koichi Kawabuchi
Venue: Mathematics and Computers in Simulation (2009)

We analyze the length of hospital stays of patients hospitalized for cataract and related diseases (Diagnosis Related Groups (DRG) 2041) in Japan, utilizing the data pertaining to 3436 patients on whom one-eye lens operations are performed. We use the discrete-type proportional hazard model to analyze variables that may affect the length of stay. We find that estimates of the Child and Other Facility Dummies are negative and significant. These variables affect the leaving rate and the length of stay. The length of stay also changes at age 40. With regard to the types of affiliated operations and treatments, the estimates of dummy variables are negative and significant at the 1% level. We also find large differences in the length of stay among hospitals, despite eliminating the influence of both the characteristics of the patient and the types of affiliated operations and treatments. The longest average length of stay is over 3.5 times as long as the shortest average length of stay. Finally, we analyze the factors pertaining to hospitals that may affect the length of stay. The estimates of the Profit and Cold Region dummies are negative and significant; in other words, the leaving rate is reduced and the length of stay is increased if the hospital becomes more profitable and is located in the cold regions of Hokkaido and Tohoku.
Extensions to the computational hemodynamics modeling of cerebral aneurysms
Authors: Juan R. Cebral
Venue:  (2008)

Image-based patient-specific CFD modeling of blood flows is important for better understanding the hemodynamics in cerebral aneurysms and their treatment. Some limitations of current methodologies have been identified, including (1) model size, (2) endovascular device modeling, (3) missing information and (4) extraction of relevant data. This work addressed the first two of these limitations. First, a Deflated Preconditioned Conjugate Gradients (DPCG) algorithm was developed to accelerate the computation of incompressible flows in the elongated geometries typically encountered in vascular models. This technique has enabled the modeling of the blood flow in complex arterial networks in a timely manner making these models practical for clinical purposes. Second, a methodology to model stented aneurysms on a patient-specific basis has been developed. This methodology has allowed the computation of the blood flow in cerebral aneurysms after the treatment with stents or other flow diverters. These two developments have extended the range of applicability of image-based CFD techniques applied to cerebral hemodynamics.