ppxscal/embedding_network huggingface dataset:
Systematic yet flexible discovery: guiding domain experts through exploratory data analysis
Authors: Adam Perer, Ben Shneiderman
Venue: Proceedings of the 13th international conference on Intelligent user interfaces (2008)

During exploratory data analysis, visualizations are often useful for making sense of complex data sets. However, as data sets increase in size and complexity, static information visualizations decrease in comprehensibility. Interactive techniques can yield valuable discoveries, but current data analysis tools typically support only opportunistic exploration that may be inefficient and incomplete. We present a refined architecture that uses systematic yet flexible (SYF) design goals to guide domain expert users through complex exploration of data over days, weeks and months. The SYF system aims to support exploratory data analysis with some of the simplicity of an e-commerce check-out while providing added flexibility to pursue insights. The SYF system provides an overview of the analysis process, suggests unexplored states, allows users to annotate useful states, supports collaboration, and enables reuse of successful strategies. The affordances of the SYF system are demonstrated by integrating it into a social network analysis tool employed by social scientists and intelligence analysts. The SYF system is a tool-independent component and can be incorporated into other data analysis tools.
A new method for generating compressed representation of transitive closure
Authors: Yangjun Chen
Venue: Proceedings of the 2008 C3S2E conference (2008)

Let G(V, E) be a digraph (directed graph) with n nodes and e edges. Digraph G* = (V, E*) is the reflexive, transitive closure of G if (v, u) &isin; E* iff there is a path from v to u in G. If we store it as a matrix, O(n2) space is required, not suitable for large graphs. In this paper, we present a new method to reduce the space overhead to O(bn), where b is the G's width, defined to be the size of a largest node subset U of G such that for every pair of nodes u, v &isin; U, there does not exist a path from u to v or from v to u. With such a compressed data structure of transitive closure, the time for checking reachability (whether a node is reachable from another node through a path) is bounded by O(logb). In addition, this data structure can be generated in O(be') time, where e' is the size of a subset of E, which contains only those edges (u, v) such that there is no path of length &ge;2 connecting u and v. We are able to show that the average value of e' is on the order of O(n1.5). Our method is suitable for both acyclic and cyclic graphs.
New ID-Based Signatures without Trusted PKG
Authors: Lingling Xu, Mingqiang Wang
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

In this paper, from bilinear pairings, we propose two ID-based signatures without trusted PKG, which solve the key escrow problem. In the schemes, the PKG is prevented forging a legal user's signature for its traceability. Under random oracle model, our schemes are both proved secure against existential forgery on adaptively chosen message and ID attack, assuming the Computational Diffie-Hellman Problem (CDHP) in Diffie-Hellman group is intractable. By comparison, our schemes have higher efficiency than the existing schemes.
Design, analysis, and implementation of a large-scale real-time location-based information sharing system
Authors: Ying Cai, Toby Xu
Venue: Proceeding of the 6th international conference on Mobile systems, applications, and services (2008)

Today's Internet is incapable of handling information like a stop sign. Such information stays in a geographic region, consistently beams to the people who move into from certain direction. This paper presents a system aimed at bridging the Internet with the physical world. The hardware platform of the system consists of a central server and a set of position-aware mobile clients that communicate with the server through means of wireless networks. Each client has a capable zone, a circular region centered on its current position with a user-defined radius. Each piece of information managed by the server is a geopage, an HTML page associated with a geographic region. As clients move, they load with the geopages implanted in their surroundings. This paper identifies the technical challenges of managing a large number of geopages that spans over a large terrain with a large number of mobile clients, and proposes a cost-effective solution that minimizes mobile communication and server processing costs. We evaluate the scalability of the proposed technique with a detailed mathematical model. The accuracy of the model is verified using simulation. We have also implemented a prototype and field tested the system in several cities.
Encryption as an Effective Tool in Reducing Wireless LAN Vulnerabilities
Authors: Jiang Li, Moses Garuba
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

The security of wireless LANs has been a source of concern for businesses and individuals who are aware of its advantages due to its flexibility. With the increase in the use of wireless LANs for enterprises and homes, where information assets are shared continually, security is of the essence. With the increase in e-commerce and e-services, there is the risk of identity and credit card theft. Encryption is seen as a major tool in the line of defense of wireless LANs. This article discusses the various security protocols used in wireless LANs and how effective they are in keeping wireless LANs secure. The risks of using these protocols are outlined and recommendations for securing wireless LANs are reviewed.
An Improved In Silico Algorithm for Output Visualization of DNA Computing Based on Real-Time PCR
Authors: Muhammad Faiz Mohamed Saaid, Zuwairie Ibrahim, Nor Haniza Sarmin
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

In the previous paper, a readout approach for the Hamiltonian Path Problem (HPP) in DNA computing based on the real-time polymerase chain reaction (PCR) was proposed. Based on this approach, real-time amplification was performed with the TaqMan probes and the TaqMan detection mechanism was exploited for the design and development of the proposed readout approach. The readout approach consists of two steps: real-time amplification in vitro using TaqMan-based real-time PCR, followed by information processing in silico to assess the results of real-time amplification, which in turn, enables extraction of the Hamiltonian path. The in silico information processing consists an algorithm to extract the Hamiltonian path based on result of in vitro real-time PCR experiment. However, this algorithm indirectly shows the Hamitonian path by only showing the location of each node for the HPP. Thus, in this paper, we modified the previous in silico algorithm such that the Hamiltonian path can be viewed directly after the in silico information processing of the TaqMan reactions based on real-time PCR is implemented. The modified algorithm can be easily implemented in the computerized application
Del.icio.us development tools
Authors: Robert DeLine
Venue: Proceedings of the 2008 international workshop on Cooperative and human aspects of software engineering (2008)

Developers need better knowledge tools to answer their information needs, rather than continuing to rely so heavily on communication with coworkers. Web sites, like the social bookmarking site Del.icio.us, might provide a way forward. They are designed to provide each user an individual incentive for entering data, but provide even more value by combining data from different users into collective knowledge. Several research projects hint that designing knowledge tools for developers using this principle would be more cost effective and provide better incentive structures for capturing knowledge.
Enzymatic Synthesis of β-D-2', 3'-unsaturated-5-fluorocytidine by Whole Cell of Lactobacillus helveticus
Authors: Yan Zheng, Li-Min Zhu, Na Qi, Bo Jiang
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

Utilizing whole cell as biocatalyst instead of free or immobilized enzyme is a potential way to reduce the cost of catalyst in enzyme-catalyzed β-D-2',3'- unsaturated-5 -fluorocytidine (D-D4FC). In this paper, D-D4FC was successfully synthesized by the whole cell of Lactobacillus helveticus (ATCC10697) for the first time. Several experimental parameters including reaction time, concentration of substrate, pH and the type of buffer were investigated; meanwhile a possible catalytic mechanism was discussed. Under the optimal reaction condition, about 50% yield of D-D4FC was obtained in 12.5 h and the cell of Lactobacillus helveticus showed good stability in the experiment. This method will be useful in the manufacture of important nucleoside analogues for anti-viral therapy.
Performance of random medium access control, an asymptotic approach
Authors: Charles Bordenave, David McDonald, Alexandre Proutiere
Venue: Proceedings of the 2008 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2008)

Random Medium-Access-Control (MAC) algorithms have played an increasingly important role in the development of wired and wireless Local Area Networks (LANs) and yet the performance of even the simplest of these algorithms, such as slotted-Aloha, are still not clearly understood. In this paper we provide a general and accurate method to analyze networks where interfering users share a resource using random MAC algorithms. We show that this method is asymptotically exact when the number of users grows large, and explain why it also provides extremely accurate performance estimates even for small systems. We apply this analysis to solve two open problems: (a) We address the stability region of non-adaptive Aloha-like systems. Specifically, we consider a fixed number of buffered users receiving packets from independent exogenous processes and accessing the resource using Aloha-like algorithms. We provide an explicit expression to approximate the stability region of this system, and prove its accuracy. (b) We outline how to apply the analysis to predict the performance of adaptive MAC algorithms, such as the exponential back-off algorithm, in a system where saturated users interact through interference. In general, our analysis may be used to quantify how far from optimality the simple MAC algorithms used in LANs today are, and to determine if more complicated (e.g. queue-based) algorithms proposed in the literature could provide significant improvement in performance.
Past, present and future of mobile payments research: A literature review
Authors: Tomi Dahlberg, Niina Mallat, Jan Ondrus, Agnieszka Zmijewska
Venue: Electronic Commerce Research and Applications (2008)

The mobile payment services markets are currently under transition with a history of numerous tried and failed solutions, and a future of promising but yet uncertain possibilities with potential new technology innovations. At this point of the development, we take a look at the current state of the mobile payment services market from a literature review perspective. We review prior literature on mobile payments, analyze the various factors that impact mobile payment services markets, and suggest directions for future research in this still emerging field. To facilitate the analysis of literature, we propose a framework of four contingency and five competitive force factors, and organize the mobile payment research under the proposed framework. Consumer perspective of mobile payments as well as technical security and trust are best covered by contemporary research. The impacts of social and cultural factors on mobile payments, as well as comparisons between mobile and traditional payment services are entirely uninvestigated issues. Most of the factors outlined by the framework have been addressed by exploratory and early phase studies.
Simulating Dynamic Covariance Structures for Testing the Adaptive Behavior of Variable Selection Algorithms (Invited Paper)
Authors: Christoforos Anagnostopoulos, Niall Adams
Venue: Proceedings of the Tenth International Conference on Computer Modeling and Simulation (2008)

Variable selection for regression is a classical statistical problem, motivated by concerns that too large a number of covariates may bring about overfitting and unnecessarily high measurement costs. Novel difficulties arise in streaming contexts, where the correlation structure of the process may be drifting, in which case it must be constantly tracked so that selections may be revised accordingly. A particularly interesting phenomenon is that non-selected covariates become missing variables, inducing bias on subsequent decisions. This raises an intricate exploration-exploitation tradeoff, whose dependence on the covariance tracking algorithm and the choice of variable selection scheme is too complex to be dealt with analytically. We hence capitalise on the strength of simulations to explore this problem, taking the opportunity to tackle the difficult task of simulating dynamic correlation structures.
On Automorphisms of Some d-Dimensional Dual Hyperovals in PG(d(d&#x00a0;+&#x00a0;3)/2, 2)
Authors: Hiroaki Taniguchi
Venue: Graphs and Combinatorics (2008)

In [3], a new d-dimensional dual hyperoval S in PG(d(d&#x00a0;+&#x00a0;3)/2, 2) for d &#x2265; 3 was constructed based on Veronesean dual hyperoval. In this note, we determine the automorphism group of the dual hyperoval S.
On solvability for parabolic equations in anisotropic spaces
Authors: Martín López Morales
Venue: Proceedings of the 7th WSEAS International Conference on Applied Mathematics (2005)

We consider the Cauchy problem for a higher order linear parabolic equation in a layer. The coefficients, the initial function and the right hand side satisfy a Hölder condition with different exponents along the different axes of independent space variables only. It is established that if these anisotropic properties are independent, then the higher derivatives with respect to the space variables of the solution to this problem also possess these properties. We establish new a priori estimates for the solution to this problem in anisotropic Hölder norm. In this connection, however, we also obtain an estimate for the modulus of continuity with respect to the time of those higher derivatives of the corresponding solutions. On the basis of our new a priori estimates to the solutions of the Cauchy problem for higher order linear parabolic equations, we obtain the solvability theorem to this problem in anisotropic Hólder spaces. These results of the linear theory are then used to obtain the local existence and uniqueness of the solution to the Cauchy problem for higher order nonlinear parabolic equations in anisotropic Hölder spaces.
The circular chromatic number of the Mycielskian of G dk
Authors: Lingling Huang, Gerard J. Chang
Venue: Journal of Graph Theory (1999)

In a search for triangle-free graphs with arbitrarily large chromatic numbers, Mycielski developed a graph transformation that transforms a graph G into a new graph &mu;(G), we now call the Mycielskian of G, which has the same clique number as G and whose chromatic number equals &chi;(G) + 1. Chang, Huang, and Zhu [G. J. Chang, L. Huang, X. Zhu, Discrete Math, to appear] have investigated circular chromatic numbers of Mycielskians for several classes of graphs. In this article, we study circular chromatic numbers of Mycielskians for another class of graphs G dk. The main result is that &chi;c(&mu;(G dk)) = &chi;(&mu;(G dk)), which settles a problem raised in [G. J. Chang, L. Huang, X. Zhu, Discrete Math, to appear, and X. Zhu, to appear]. As &chi;c(G dk) = ${k}\over{d}$ and &chi;(G dk) = $\lceil {{k}\over{d}} \rceil$, consequently, there exist graphs G such that &chi;c(G) is as close to &chi;(G) - 1 as you want, but &chi;c(&mu;(G)) = &chi;(&mu;(G)). &copy; 1999 John Wiley Sons, Inc. J Graph Theory 32: 6371, 1999
Switchblade: enforcing dynamic personalized system call models
Authors: Christof Fetzer, Martin Süßkraut
Venue: Proceedings of the 3rd ACM SIGOPS/EuroSys European Conference on Computer Systems 2008 (2008)

System call interposition is a common approach to restrict the power of applications and to detect code injections. It enforces a model that describes what system calls and/or what sequences thereof are permitted. However, there exist various issues like concurrency vulnerabilities and incomplete models that restrict the power of system call interposition approaches. We present a new system, SwitchBlade, that uses randomized and personalized fine-grained system call models to increase the probability of detecting code injections. However, using a fine-grain system call model, we cannot exclude the possibility that the model is violated during normal program executions. To cope with false positives, SwitchBlade uses on-demand taint analysis to update a system call model during runtime.
Web page retrieval in ubiquitous sensor environments
Authors: Takuya Maekawa, Yutaka Yanagisawa, Yasushi Sakurai, Yasue Kishino, Koji Kamei, Takeshi Okadome
Venue: Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval (2008)

This paper proposes new concept of query free web search for daily living. We ordinarily benefit from additional information about our daily activities that we are currently engaged in. When washing a coffee maker, for example, we receive the benefit if we obtain such information as 'cleaning a coffee maker with vinegar removes its stain well.' Our proposed method automatically searches for a web page including such information relates to an activity of daily living when the activity is performed. We assume that wireless sensor nodes are attached to daily objects to detect object use; our method makes a query from the names of objects which are used. Then, the method retrieves a web page relates to the activity of daily living by using the query.
Robust checkerboard recognition for efficient nonplanar geometry registration in projector-camera systems
Authors: Weibin Sun, Xubo Yang, Shuangjiu Xiao, Wencong Hu
Venue: Proceedings of the 5th ACM/IEEE International Workshop on Projector camera systems (2008)

Projector-camera systems always need complicated geometry calibration to get a correct display result on nonplanar projection surface. Geometry registration of most calibration methods dealing with arbitrary surfaces is done by projecting a set of structure light patterns or by manually 3D modeling, which are both time-consuming. In this paper, we propose a robust checkerboard calibration pattern recognition method to help nonplanar surface geometry registration. By approximating the nonplanar surface to be composite of many planar quad patches, pixels mapping between the calibration camera and a projector can be got by projecting only one checkerboard calibration pattern recognized by our method. Compared with geometry registration with structure light or encoded points, which need project many images, our method can be more efficient. Our recognition method has two steps: corner detection and checkerboard pattern match. Checkerboard internal corners are defined as special conjunction points of four alternating dark and bright regions. A candidate corner's neighbor points within a rectangular or a circular window are treated as in different one-point-width layers. By processing the points layers in corner detection, we transform the 2D points distribution into 1D, which simplifies the regions amount counting and also improves the robustness against noises caused by deformation and complex illumination. After corner detection, the pre-known checkerboard grids rows and columns amounts are used to match and decide the right checkerboard corners from the results that have found. Regions boundary data produced during the corner detection also assist the matching process.
Normal modes of oscillation in an inhomogeneous hanging chain using Maple
Authors: Daniel Esteban Sierra Sosa
Venue: Proceedings of the 10th WSEAS International Conference on APPLIED MATHEMATICS (2006)

The normal modes of oscillation in a hanging chain have an interest way of solution, it will be analyze some particular cases of density distribution. The paper also covers a general case for any power of the position. Some graphics of the behavior along with the solution of the proposed problem will be presented. The conclusion incorporate a view of the system equations and graphics solved using the Maple Software package.
Virtual Links: intergenerational learning and experience sharing across age divides and distances
Authors: Anne Inga Hilsen, Richard Ennals
Venue: AI Society (2008)

This article presents and discusses &#x201c;Virtual Links&#x201d;. This builds on &#x201c;The Golden Link&#x201d;, a model which was developed to address the challenge of how to make experience based competencies of senior workers available to the organisation and to younger workers with less experience. &#x201c;Virtual Links&#x201d; support cross-generational communication and learning, as well as enabling access for mobile workers to the knowledge of experienced seniors not physically present.
Simulated neural dynamics of decision-making in an auditory delayed match-to-sample task
Authors: Shihua Wen, Antonio Ulloa, Fatima Husain, Barry Horwitz, Jos&#x00e9; L. Contreras-Vidal
Venue: Biological Cybernetics (2008)

An important goal of research on the cognitive neuroscience of decision-making is to produce a comprehensive model of behavior that flows from perception to action with all of the intermediate steps defined. To understand the mechanisms of perceptual decision-making for an auditory discrimination experiment, we connected a large-scale, neurobiologically realistic auditory pattern recognition model to a three-layer decision-making model and simulated an auditory delayed match-to-sample (DMS) task. In each trial of our simulated DMS task, pairs of stimuli were compared each stimulus being a sequence of three frequency-modulated tonal-contour segments, and a &#x201c;match&#x201d; or &#x201c;nonmatch&#x201d; button was pressed. The model&#x2019;s simulated response times and the different patterns of neural responses (transient, sustained, increasing) are consistent with experimental data and the simulated neurophysiological activity provides insights into the neural interactions from perception to action in the auditory DMS task.
Surface modification of a porous polyurethane through a culture of human osteoblasts and an electromagnetic bioreactor
Authors: L. Fassina, L. Visai, M. G. Cusella De Angelis, F. Benazzo, F. Magenes
Venue: Technology and Health Care (2007)

There is increasing interest in new biomaterials and new culture methods for bone tissue engineering, in order to produce, in vitro, living constructs able to integrate in the surrounding tissue. Using an electromagnetic bioreactor (magnetic field intensity, 2 mT; frequency, 75 Hz), we investigated the effects of electromagnetic stimulation on SAOS-2 human osteoblasts seeded onto a porous polyurethane. In comparison with control conditions, the electromagnetic stimulation caused higher cell proliferation, increased surface coating with decorin and type-I collagen, and higher calcium deposition. The immunolocalization of decorin and type-I collagen showed their colocalization in the cell-rich areas. The use of an electromagnetic bioreactor aimed at obtaining the surface modification of the porous polyurethane in terms of cell colonization and coating with calcified matrix. The superficially modified biomaterial could be used, in clinical applications, as an implant for bone repair.