ppxscal/embedding_network huggingface dataset:
Optimisation of the pilot-to-data power ratio in the wireless MIMO-OFDM system with low-complexity MMSE channel estimation
Authors: Eugene Golovins, Neco Ventura
Venue: Computer Communications (2009)

Multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) communication systems are currently being viewed as a main candidate for the next generation broadband wireless access interfaces providing high throughput. However, a considerable potential gain in spectral efficiency is challenged by the receiver's ability of accurate data symbol identification at the output of the radio channel. Performance of the MIMO detectors strongly depends on both the received signal-to-noise power ratio (SNR) and the retrieved channel state information (CSI), which can be obtained using the channel estimation techniques relying on pilot symbol transmission on the dedicated subcarriers. Necessity to improve channel estimation and detection performance concurrently leads to the dilemma of the optimal power assignment to the data and pilot subcarriers as these are the conflicting requirements under the total transmit power constraint. We derive an analytical solution of the described problem in the form of weak and tight upper bounds on the pilot-to-data power ratio (PDR) given the system design parameters (number of subcarriers, number of pilots, number of transmit antennas, model order of the channel response, SNR). The resultant PDR equations can be applied to OFDM systems with arbitrary arrangement of the pilot subcarriers operating in an arbitrary multipath channel, not just limited to the equispaced optimal pilot pattern and the channel with the uniform sample-spaced power-delay profile as studied in the previous works. In an adaptive system, which is capable to adjust transmit signal configuration (e.g., block length, number of pilot subcarriers or antennas) according to the established channel conditions, an optimal parameter tuning is desirable for each operational mode. The closed-form PDR expressions and their analysis presented in this work are designated to alleviate the challenging task of the on-the-fly system optimisation as they represent relatively simple functional relationships.
A neural network approach to the fuzzy transform
Authors: Martin Štěpnička, Ondřej Polakovič
Venue: Fuzzy Sets and Systems (2009)

The paper deals with the F-transform technique which was introduced as a method for an approximate representation of continuous functions. The same task is solved by many methods from different areas. Neural networks also belong to techniques which have been proved to be powerful for approximation objectives. They provide us with many advantages, especially incremental way of learning parameters. The paper inherits neural approaches to the F-transform method and presents experiments justifying the proposed approach. Incremental way of determination of certain parameters of the F-transform method which were up to now given by batch formula enriches possible areas of application of the method by fast on-line processes. Moreover, the neural approach is demonstrated to be an appropriate one for finding such fuzzy partition of a domain which respects better a given set of measured samples which are to be approximated by a continuous function with no predetermined shape.
A Reputation System with Anti-Pollution Mechanism in P2P File Sharing Systems
Authors: Qi Mei, Guo Yajun, Yan Huifang
Venue: International Journal of Distributed Sensor Networks (2009)

File pollution has become a very serious problem in peer-to-peer file sharing systems, because of which it greatly reduces the effectiveness of systems. Users downloaded pollution files not only consumed bandwidth, but were also likely to share polluted files without checking. If these polluted files carry a virus, Trojan horse, or other malicious code, the loss of users would be disastrous. There is much research done on reputation-based anti-pollution mechanisms. Peer reputation systems and object reputation systems are two representatives reputation-based anti-pollution mechanisms currently. Peer reputation systems only care about the reputation of file providers, while object reputation systems only care about the reputation of sharing files. This paper proposes an anti-pollution mechanism combined with peer reputation and object reputation. Different from former research, we calculate the reputation of sharing files by the reputation of the voting peer. That is, object reputation is weighted by peer reputation. The reputation of the voting peer is built by its direct trust value and recommended trust value. Direct trust considers the trust of Direct Interaction Experience and the trust of Voting Similar Experience. Severe penalty strategy and voting incentive mechanism are introduced in calculating direct trust value. Therefore, a good user who uploads unpolluted files and voting on files actively can have a higher reputation, while a malicious user who uploads polluted files or voting unhonestly would have his reputation reduced sharply. Our expectation is that users for their own reputation will delect polluted files as soon as possible. These strategies give users an incentive to awareness of pollution, consequently isolate the polluters effectively. Our reputation mechanism is intended to prevent pollution spread by stimulating the awareness of users to delete files as soon as possible. At last, we simulate a P2P file sharing system to assess our reputation mechanism. The simulation results show that, compared to the object reputation system, our reputation mechanism convergence is faster, and has a better anti-pollution performance.
Three heuristics for improving centralized routing in large long-haul computer communication networks
Authors: Ivan M. Pesic, Daniel W. Lewis
Venue: Proceedings of the May 16-19, 1983, national computer conference (1983)

Several algorithms have proven to be useful in computing the shortest path between two nodes in a network. Their complexity depends on the problem definition and size of the network measured by the total number of nodes N. In these algorithms, finding all the shortest paths from a fixed node is a computation of complexity O(N x N). These algorithms have been used successfully in long-haul networks for many years. Recent growth of such networks to large numbers of nodes (e.g., N > 500) demands a more efficient approach. This paper develops three heuristics based on measured topological characteristics of computer communication networks and applies them in the construction of faster algorithms. Determination of the shortest path between two random nodes is then shown to require 50 to 60% less computation.
Modeling and formulation of a novel microoptoelectromechanical gyroscope
Authors: Bohua Sun, Bo Zhang, Mohamed Toriq Khan
Venue: Journal of Nanomaterials (2008)

This paper proposed a novel design of microgyroscope based on MEMS structures and optic interferometric microdisplacement measurement technique. The gyroscope consists of microvibrator and interferometric readout. Using Coriolis force, the vibrator transfers the system rotation into a forced vibration; the induced vibration can be sensed by the interferometric microdisplacement measurement system. The optic measurement system has two mirrors which will reflect two rays into a detector. The comprehensive studies on the formulation and analysis of the proposed gyroscope have been undertaken; two key sensor equations have been derived in the first time in the world: (1) relation between rotation and phase shift of light Δϕ = (4πl0/λ) + (8π/λ)(xmaxQy/ωy)Ω(t) sin(ωdt), (2) relation between rotation and interferometric intensity of light I(t) ≅ (8π/λ)(xmaxQy/ωy)Ω(t) sin(ωdt) sin(4πl0/λ). The comparison of the proposed gyroscope and well-know Sagnac formulation has been investigated; it shown that the proposed model is much better than Sagnac ones. The new model has finally get rid of needing very long fiber in the case of Sagnac gyroscope. The innovative model gives a new hope to fabricate high accurate and cheaper gyroscope. To date, the proposed gyroscope is the most accurate gyroscope.
The 'how' and 'why' of persistent information security
Authors: Merv Matson, Mihaela Ulieru
Venue: Proceedings of the 2006 International Conference on Privacy, Security and Trust: Bridge the Gap Between PST Technologies and Business Services (2006)

A file level information security technology that applies everywhere, every time, is introduced. The security is always 'on', as much 'in the wild' as behind the firewall or in the VPN tunnel. The broad strokes of structure and operation are discussed in terms of a specific system, RightsEnforcer. The technology is currently being deployed in the Adaptive Risk Management Lab at the University of New Brunswick as part of a testbed supporting emergency response operations.
Seamless Teamwork: Using Microsoft SharePoint Technologies to Collaborate, Innovate, and Drive Business in New Ways (BP-Other)
Authors: Michael Sampson
Venue:  (2008)

Learn how you can take advantage of Microsoft SharePoint Products and Technologies to enhance collaboration, fuel team productivity, and improve your business processes. Many business tools and processes focus on improving the productivity of the individual an approach that's increasingly out of step with the collaborative, team-based work needed for shared project goals and business results. Learn Michael Sampson s Seven Pillars of Team Productivity and put them into practice using the powerful collaboration capabilities in SharePoint Products and Technologies. Discover how you can set up SharePoint Products and Technologies effectively for your team, including providing access to team data, enabling group collaboration in a virtual environment, using Microsoft Office LiveMeeting, setting up team calendaring and action points, and building social networks with blogs, search, and SharePoint MySite. Find out how other organisations are using SharePoint to their advantage. And learn exactly how your team can benefit by collaborating on documents and presentations, holding group discussions, and co-ordinating events and team meetings.
A New Method for Vertical Handoff between WLANs and UMTS in Boundary Conditions
Authors: Majid Fouladian, Faramarz Hendessi, Alireza Shafieinejad, Morteza Rahimi, Mahdi M. Bayat
Venue: Proceedings of the 2009 International Conference on Computer Engineering and Technology - Volume 01 (2009)

We propose a new vertical handoff method in which the number of signaling and registration processes is lowered as a result of reduced utilization of home agent and correspondent nodes while users are mobile. Throughput performance of the integrated network is improved by reducing handoff delays and packet losses. Special conditions such as boundary condition also considered. Performance and delay evaluations which done by ns-2 are presented to demonstrate the effectiveness of the proposed scheme
Optimal control of a spin system acting on a single quantum bit
Authors: Evgenia Kirillova, Thomas Hoch, Karlheinz Spindler
Venue: WSEAS Transactions on Mathematics (2008)

We study a quantum spin system acting on single quantum bit. The evolution of this system is governed by the Schrödinger equation which takes the form of a right-invarient system on the special unitary group SU(2) with two control inputs. Using a suitable version of Pontryagin's Principle which is tailor-made for control problems on Lie groups, the optimal controls are devided in two cases: the energy-optimal case (in which the control effort is minimized for a specified end time) and the time-optimal case (in which the control duration is minimized for given constraints on the size of the controls).
Quantification Analysis for NLPCA-Based Stiction Diagnostic Tool
Authors: H. Zabiri, M. Ramasamy, I. S. Y. Teh
Venue: Proceedings of the 2009 International Conference on Advanced Computer Control (2009)

A significant number of control loops in process plants perform poorly due to control valve stiction. Stiction in control valves is the most common and long standing problem in industry, resulting in oscillations in process variables which subsequently lowers product quality and productivity. Developing a method to detect valve stiction in the early phase is imperative to avoid major disruptions to the plant operations. In this paper, nonlinear principal component analysis (NLPCA)-based stiction diagnostic tool is presented. Results from simulated case studies show that with proper quantification analysis, NLPCA shows a very promising capability for stiction diagnosis.
Usability and performance of secure mobile messaging using public key infrastructure
Authors: Nor Badrul Anuar, Lai Ngan Kuen, Omar Zakaria, Abdullah Gani, Ainuddin Wahid Abdul Wahab
Venue: Proceedings of the 7th conference on Data networks, communications, computers (2008)

Human life style change substantially when the cellular technology goes commercial. Short Messaging Service (SMS) and Multimedia Message Service (MMS) play important roles in our daily life. The recent report carried out by Mobile Data Association (MDA) [1] shows that the yearly growth of SMS and MMS achieves 30 percent from year 2007 to 2008. Conventional SMS/MMS does not provide any protection on the text message sent. It causes the security threats such as privacy and message integrity. Mobile users seek for the solution to allow them to exchange confidential information in a safe environment. This leads to the implementation of M-PKI, which is an application that secures the mobile messaging service by using public key infrastructure (PKI). This new approach allows the end-user to send private and classified message via SMS. Besides, M-PKI offers message classification. This feature is specially designed to meet various user requirements on the level of security and performance. The usage and performance of M-PKI messaging in performing encryption and decryption process are tested on selected java-enabled phone.
The Simple Reachability Problem in Switch Graphs
Authors: Klaus Reinhardt
Venue: Proceedings of the 35th Conference on Current Trends in Theory and Practice of Computer Science (2009)

Switch graphs as introduced in [Coo03] are a natural generalization of graphs where edges are interpreted as train tracks connecting switches: Each switch has an obligatory incident edge which has to be used by every path going through this switch. We prove that the simple reachability problem in switch graphs is NP-complete in general, but we describe a polynomial time algorithm for the undirected case. As an application, this can be used to find an augmenting path for bigamist matchings and thus iteratively construct a maximum bigamist matching for a given bipartite graph with red and blue edges, that is the maximum set of vertex disjoint triples consisting of one bigamist vertex connected to two monogamist vertices with two different colors. This this gives an independent direct solution to an open problem in [SGYB05].
Bayesian Co-clustering
Authors: Hanhuai Shan, Arindam Banerjee
Venue: Proceedings of the 2008 Eighth IEEE International Conference on Data Mining (2008)

In recent years, co-clustering has emerged as a powerful data mining tool that can analyze dyadic data connecting two entities. However, almost all existing co-clustering techniques are partitional, and allow individual rows and columns of a data matrix to belong to only one cluster. Several current applications, such as recommendation systems and market basket analysis, can substantially benefit from a mixed membership of rows and columns. In this paper, we present Bayesian co-clustering (BCC) models, that allow a mixed membership in row and column clusters. BCC maintains separate Dirichlet priors for rows and columns over the mixed membership and assumes each observation to be generated by an exponential family distribution corresponding to its row and column clusters. We propose a fast variational algorithm for inference and parameter estimation. The model is designed to naturally handle sparse matrices as the inference is done only based on the non-missing entries. In addition to finding a co-cluster structure in observations, the model outputs a low dimensional co-embedding, and accurately predicts missing values in the original matrix. We demonstrate the efficacy of the model through experiments on both simulated and real data.
Using empirical mode decomposition for iris recognition
Authors: Chien-Ping Chang, Jen-Chun Lee, Yu Su, Ping S. Huang, Te-Ming Tu
Venue: Computer Standards Interfaces (2009)

Iris recognition is known as an inherently reliable technique for human identification. Empirical Mode Decomposition (EMD), an adaptive multi-resolution decomposition technique, appears to be suitable for non-linear, non-stationary data analysis. Based on EMD, a fully data-driven method without using any pre-determined filter or wavelet function, an iris recognition scheme is presented by modifying EMD as a low-pass filter to analyze the iris images. To evaluate the efficacy of the proposed approach, three different similarity measures are used. Experimental results show that three metrics have all achieved promising and similar performance. Therefore, the proposed method demonstrates to be feasible for iris recognition and EMD is suitable for feature extraction.
Four-point curve subdivision based on iterated chordal and centripetal parameterizations
Authors: Nira Dyn, Michael S. Floater, Kai Hormann
Venue: Computer Aided Geometric Design (2009)

Dubuc's interpolatory four-point scheme inserts a new point by fitting a cubic polynomial to neighbouring points over uniformly spaced parameter values. In this paper we replace uniform parameter values by chordal and centripetal ones. Since we update the parameterization at each refinement level, both schemes are non-linear. Because of this data-dependent parameterization, the schemes are only invariant under solid body and isotropic scaling transformations, but not under general affine transformations. We prove convergence of the two schemes and bound the distance between the limit curve and the initial control polygon. Numerical examples indicate that the limit curves are smooth and that the centripetal one is tighter, as suggested by the distance bounds. Similar to cubic spline interpolation, the use of centripetal parameter values for highly non-uniform initial data yields better results than the use of uniform or chordal ones.
(Self-)Evaluation of computer competence: How gender matters
Authors: Monika Sieverding, Sabine C. Koch
Venue: Computers Education (2009)

Is the negative stereotype of women with regard to computer competence still exerting power in our society? In this study, 206 participants observed a target person (either a woman or a man) on a video who was about to solve a complex computer task. Participants had to estimate whether the target person was successful on this task in a limited amount of time. After they had received the information that the target person had solved the task successfully in the required time period, and that the person's performance was above average, they were asked to provide a reason for the success (luck vs. skill attribution) and to evaluate the general computer competence of the target. Then, participants had to evaluate their own (hypothetical) computer competence in comparison to the target. Results suggest that for the direct evaluation of the target persons and for the causal attribution of success, no systematic gender-related biases occurred. In the self-ratings of participants; however, findings showed that (a) women judged their computer competence to be lower than did men, and (b) both women and men judged their own hypothetical performance in the computer-related task to be relatively higher when comparing it to the identically scripted performance of a woman vs. a man.
An Improved Neural Network Algorithm and its Application in Sinter Cost Prediction
Authors: Bin Wang, Bin Yang, Jinfang Sheng, Mengsheng Chen, Guoqiang He
Venue: Proceedings of the 2009 Second International Workshop on Knowledge Discovery and Data Mining (2009)

This paper studies various training algorithms of BP neural network and proposes an improved conjugate gradient algorithm which combines conjugate gradient algorithm with inexact line search route based on generalized Curry principle. The proposed algorithm has global convergence, optimizes the learning steps using new line search rules and improves the convergence speed. The new algorithm is applied in the cost prediction of actual sintering production. Simulation results show that the algorithm has better convergence compared with traditional conjugate gradient algorithms. The MSE of prediction is 0.0098 and accuracy rate reaches 94.31%.
A Comprehensive Model of Usability
Authors: Sebastian Winter, Stefan Wagner, Florian Deissenboeck
Venue: Engineering Interactive Systems: EIS 2007 Joint Working Conferences, EHCI 2007, DSV-IS 2007, HCSE 2007, Salamanca, Spain, March 22-24, 2007. Selected Papers (2008)

Usability is a key quality attribute of successful software systems. Unfortunately, there is no common understanding of the factors influencing usability and their interrelations. Hence, the lack of a comprehensive basis for designing, analyzing, and improving user interfaces. This paper proposes a 2-dimensional model of usability that associates system properties with the activities carried out by the user. By separating activities and properties, sound quality criteria can be identified, thus facilitating statements concerning their interdependencies. This model is based on a tested quality meta-model that fosters preciseness and completeness. A case study demonstrates the manner by which such a model aids in revealing contradictions and omissions in existing usability standards. Furthermore, the model serves as a central and structured knowledge base for the entire quality assurance process, e.g. the automatic generation of guideline documents.
On Satisfying Timing and Resource Constraints in Distributed Multimedia Systems
Authors: Costas Mourlas, David Duce, Michael Wilson
Venue: Proceedings of the 1999 IEEE International Conference on Multimedia Computing and Systems - Volume 02 (1999)

In this paper, we present a new synchronization strategy for multimedia applications executed in a distributed environment. This strategy makes the timing properties of the system and the quality of the media presentations predictable since one is able to determine analytically whether the timing requirements of each multimedia application will be met, and if not, which timing requirements will fail. The proposed synchronization protocol provides deterministic guarantees and service reliability that can't be compromised by resource contention. Thus, the application can maintain the initial quality of service (QoS) level without encountering unpredictable delays and blocking due to synchronization.
Student Authentication for Oral Assessment in Distance Learning Programs
Authors: Barry Hayes, John V. Ringwood
Venue: IEEE Transactions on Learning Technologies (2008)

The past decade has seen the proliferation of e-learning and distance learning programs across a wealth of discipline areas. In order to preserve maximum flexibility in outreach, student assessment based exclusively on remotely submitted work has become commonplace. However, there is also growing evidence that e-learning also provides increased opportunity for plagiarism, with obvious consequences for learning effectiveness. This paper reports on the development of a prototype student authentication system, designed for use with a graduate e-learning program. The proposed system can be used to authenticate telephone-based oral examination which can, in turn, be used to confirm a student's ability in relation to submitted assignments and on-line test results. The prototype low-cost system is shown to be sufficiently accurate to act as an effective deterrent against plagiarism.