ppxscal/embedding_network huggingface dataset:
Optimal constructions of fault tolerant optical linear compressors and linear decompressors
Authors: Cheng-Shang Chang, Jay Cheng, Tsz-Hsuan Chao, Duan-Shin Lee
Venue: IEEE Transactions on Communications (2009)

The constructions of optical queues is one of the most critically sought after optical technologies in all-optical packet-switched networks, and constructing optical queues directly via optical Switches and fiber Delay Lines (SDL) has received a lot of attention recently in the literature. A practical and challenging issue in the constructions of optical queues is on the fault tolerant capability of such constructions. In this paper, we focus on the constructions of fault tolerant optical linear compressors and linear decompressors. The basic network element for our constructions is scaled optical memory cell, which is constructed by a 2×2 optical crossbar switch and a fiber delay line. We first obtain a fundamental result on the minimum construction complexity of a linear compressor by using fiber delay lines as the storage devices for the packets queued in the linear compressor. This result shows that one of our previous constructions of a linear compressor by a concatenation of scaled optical memory cells is an optimal construction in the sense of minimizing the construction complexity. However, such an optimal construction lacks the fault tolerant capability. To construct a linear compressor with fault tolerant capability, we give a multistage construction of a self-routing linear compressor by a concatenation of scaled optical memory cells, and show that if the delays, say d1, d2, ..., dM, of the fibers in the scaled optical memory cells satisfy a certain condition (specifically, the condition in (A2) given in Section IV-A), then our multistage construction can be operated as a self-routing linear compressor with maximum delay Σi=1M-F di in the worst case even after up to F of the M scaled optical memory cells fail to function properly, where 0 ≤ F ≤ M - 1. Furthermore, we prove that our multistage construction with the fiber delays d1, d2, ..., dM given by the generalized Fibonacci sequence of order F is the best among all of the constructions of a linear compressor that can tolerate up to F faulty scaled optical memory cells by using M scaled optical memory cells. Similar results are also obtained for the constructions of fault tolerant linear decompressors.
I seek you: searching and matching individuals in social networks
Authors: Marti Motoyama, George Varghese
Venue: Proceeding of the eleventh international workshop on Web information and data management (2009)

The first task any individual faces after joining an online social network (OSN) is locating friends that are present on that particular site. Most OSNs offer some variation of a tool that imports email contact lists to facilitate the task of finding one's friends. However, given that OSNs attempt to reconnect individuals with past acquaintances, one might not have access to the email address for a long lost friend. Furthermore, people tend to utilize a number of aliases online, meaning that an email address cannot always be used to reliably find a friend. Thus, new members must still manually search for friends based on a number of biographical attributes, such as gender, age, hometown, etc. It is not clear, however, what attributes are useful for conducting the search. Even after the search has been performed, the person performing the search might be left with a number of candidate profiles. In this paper, we develop a system for searching and matching individuals in OSNs. We evaluate the efficacy of our person matching techniques by measuring the overlap between social networks, and comparing our results to those published by compete.com. We then look at several interesting properties of overlapping profiles in both networks.
Location update cost of distance-based scheme for PCS networks with CTRW model
Authors: Qinglin Zhao, Soung C. Liew, Yao Yu
Venue: IEEE Communications Letters (2009)

This letter concerns the optimization of the dynamic location-update area (LA) for the per-user distance-based scheme in personal communication service (PCS) networks. We have two main contributions: (1) under the general and popular one-dimensional (1-D) continuous-time random walk (CTRW) mobility model, we propose a novel framework to analyze the location update cost; (2) with this framework, we investigate the impact of call arrivals and the initial position of the mobile terminal (MT) on the position of the LA, which was neglected by previous work. Simulation shows that our theoretical model is very accurate.
Security Evaluation Method Based on Host Resource Availability
Authors: Cuixia Gao, Zhitang Li, Haigang Song
Venue: Proceedings of the 2009 Third International Conference on Multimedia and Ubiquitous Engineering (2009)

After analyzing malicious attacks against host that affect the host resource usage a method is presented to evaluate the security situation of host system based on host resource availability. A group of factors that can reflect the host resource availability features in a fixed time window are selected as the evaluation metrics. Based on the large samples, the information entropy gain method is applied to determine the importance of evaluation results for different metrics. Then by using analytic hierarchy process (AHP) method, the evaluation results are regarded as the normalized abnormality value to evaluate the host risk status. If the value of host risk status is larger than the threshold then an alert is triggered. Experiments show that this method can reasonably evaluate the host risk status caused by most of attacks.
Lower dropout rates and better grades through revised course infrastructure
Authors: Jussi Kasurinen, Uolevi Nikula
Venue: Proceedings of the 10th IASTED International Conference on Computers and Advanced Technology in Education (2007)

Programming skill is one of the skills everyone tends to expect from a computer science graduate. However, recently many universities have reported high dropout rates and problems grasping the basic programming concepts in the first programming courses. In some cases such problems can severely disturb the normal advancement of the studies since basic programming skill is often a prerequisite for advanced courses. In this paper these problems are tackled by revising the course design emphasizing a close integration of different course elements, and developing an up to date infrastructure for the first programming course. The course was designed based on the imperative-first approach, and implemented with the Python programming language. In addition to justifying the selections made, we also report the results of the first course implementation and compare them with the results from the previous course. Overall the results indicate that the students were performing better than before. With the new course, students felt that the course had become more interesting and useful, even though the course was still considered laborious and challenging. Thus we intend to continue refining the course design and infrastructure while moving the improvement focus on the teaching practices to further improve the learning outcomes of the course.
Building an automatic annotate image system by using bootstrapping
Authors: Yun-Long Lin, Chin-Hwa Kuo, Nai-Lung Tsao
Venue: Proceedings of the 10th IASTED International Conference on Computers and Advanced Technology in Education (2007)

The images are always playing an important role on teaching and learning. However, it is not easy to get sufficient and appropriate images rapidly for these purposes. In this paper, we have designed a database that can automatically collect and classify images; This database is characterized by high level features to image classifying. Its features include: extending a keyword through bootstrapping construction. Aside from using bootstrapping construction to expand keywords and to classify images, we have also added a discriminative feature metric to increase the precision and recall rates of image classifying to our standards. Finally, we apply this technique on an image archives management system, named "Campus Image System". Instructors and students can get appropriate images via this system, for supporting their teaching or learning purposes.
Mitigation of cross-modulation interference in UWB energy detector receivers
Authors: Xiantao Cheng, Yong Liang Guan
Venue: IEEE Communications Letters (2009)

For ultra-wideband (UWB) pulse position modulation (PPM) signalling, cross-modulation interference (CMI) occurs when the amount of the pulse-position shift is less than the maximum excess delay of the multipath channel. Such CMI severely degrades the bit error rate (BER) performance of energy detector (ED) receivers. To alleviate the adverse effect of CMI, in this letter we propose an enhanced energy detector (EED) combined with block-orthogonal-coded PPM (BOC-PPM). Each PPM frame is chopped into several sub-windows and the outputs of sub-windows are combined to form the decision statistic. The optimum combining scheme is derived based on the maximum likelihood (ML) criteria. Through analysis and simulations, we show that E-ED can significantly suppress CMI and thus performs well in the CMI region.
A minimum mean-squared error relay for the two-way relay channel with network coding
Authors: Moonseo Park, Seong-Lyun Kim
Venue: IEEE Communications Letters (2009)

In this letter, we consider the two-way relay channel (TWRC) employing network coding. In TWRC, a conventional relay first decodes symbols from each user and combines (network coding) them using, for example, the XOR (eXclusive OR) operation. However, it may be suboptimal for the relay to use this concatenated approach, when the channels are noisy and the cost criterion is source distortion. Instead, we propose a new relay scheme that generates network coded symbols by performing symbol estimation and network coding operation jointly, in order to minimize the source distortion at the users.
A low-complexity Max-Log-MAP detector
Authors: Nils Graef, Joachim S. Hammerschmidt, Carl-Erik W. Sundberg
Venue: IEEE Transactions on Communications (2009)

A low-complexity soft-output Max-log-MAP (maximum a posteriori probability) detector for N2-QAM is exemplified for a 64-QAM 2×M multiple-input-multiple-output (MIMO) system, exhibiting the following novel features: (1) hierarchical formulation of the exhaustive metric calculation to reduce the number of candidate tests by a factor of N per received symbol, and (2) multiplier-free implementation of the exhaustive search with 8-fold parallelization. The computational complexity is reduced by a factor of about 250, resulting in a chip area of 0.031 mm2 using 65nm CMOS.
A fully differential comparator-based switched-capacitor ΔΣ modulator
Authors: Mu-Chen Huang, Shen-Iuan Liu
Venue: IEEE Transactions on Circuits and Systems II: Express Briefs (2009)

In this brief, a fully differential comparator-based switched-capacitor (CBSC) second-order delta-sigma (ΔΣ) modulator is Presented. To ensure differential operation, the CBSC ΔΣ modulator utilizes a common-mode feedback circuit to balance the pull-up current and the pull-down current in the ramp generator. This modulator has been fabricated in a standard O.18-µm CMOS process. The active area is O.21 mm2, and the power consumption, excluding output buffers, is 0.42 mW from a 1.8-V supply. This modulator achieves 65.3-dB signal-to-noise-plus-distortion ratio and an input dynamic range of 71 dB when sampled at 2.56 MS/s (OSR = 64).
On a buffering hypothesis in 802.11 analytic models
Authors: K. D. Huang, K. R. Duffy
Venue: IEEE Communications Letters (2009)

Using detailed statistical analysis of data taken from simulations and test-bed experiments, we have recently reported the inappropriateness of a queue-decoupling approximation that has been implicitly adopted by many distinct authors to incorporate queueing behavior in analytic models of finite load 802.11 networks. In the present paper we show that this flawed hypothesis leads to network throughput prediction errors in the presence of stations with asymmetric offered loads. We suggest that care should be taking in drawing deductions from models that adopt this hypothesis and that further modeling innovation is necessary.
Tree-pattern-based duplicate code detection
Authors: Hyo-Sub Lee, Kyung-Goo Doh
Venue: Proceeding of the ACM first international workshop on Data-intensive software management and mining (2009)

This paper presents a tree-pattern-based method of automatically and accurately finding code clones in program files. Duplicate tree-patterns are first collected by anti-unification algorithm and redundancy-free exhaustive comparisons, and then finally clustered. The algorithm is designed in such a way that the same comparison is not repeated for speed, while thoroughly examining every possible pairs of tree patterns for accuracy. Our method maintains the syntax structure of code in tree-pattern clusters, which gives the flexibility of finding different types of clones while keeping the precision.
On decoding binary perfect and quasi-perfect codes over Markov noise channels
Authors: Haider Al-Lawati, Fady Alajaji
Venue: IEEE Transactions on Communications (2009)

We study the decoding problem when a binary linear perfect or quasi-perfect code is transmitted over a binary channel with additive Markov noise. After examining the properties of the channel block transition distribution, we derive sufficient conditions under which strict maximum-likelihood decoding is equivalent to strict minimum Hamming distance decoding when the code is perfect. Additionally, we show a near equivalence relationship between strict maximum likelihood and strict minimum distance decoding for quasi-perfect codes for a range of channel parameters and the code's minimum distance. As a result, an improved (complete) minimum distance decoder is proposed and simulations illustrating its benefits are provided.
On rearrangeability of tandem connection of banyan-type networks
Authors: Shuo-Yen Robert Li, Xuesong Jonathan Tan
Venue: IEEE Transactions on Communications (2009)

A multistage interconnection network (MIN) consisting of 2 × 2 nodes constructs a nonblocking switch if the network is rearrangeable. When a 2n × 2n bit-permuting network is rearrangeable with the minimum depth of 2n - 1, the initial (resp. final) n stages of the network form a banyan-type network and hence the network is equivalent to the tandem connection between two banyan-type networks. Let γ denote the guide permutation of a 2n × 2n banyan-type network and τ the trace permutation of another. These are permutations on numbers from 1 to n. This paper proves that, when the permutation γτ-1 is the transposition between the number n and some number k < n, the tandem connection between the two networks is rearrangeable. This sufficient condition for rearrangeability covers a wide class of tandem connections. For example, the first network in tandem can be the omega network appended with the banyan exchange of any rank while the second is the reversed omega network.
Fooling Public-Key Watermarking Detectors with Optimal Color Noise
Authors: Yongdong Wu, Robert H. Deng
Venue: Proceedings of the 2009 International Conference on Multimedia Information Networking and Security - Volume 01 (2009)

Public-key watermarking methods should have two properties: (1) allowing everyone to determine whether a watermark exists in an image or not; (2) having a high detection probability in case of malicious modification. This paper proposes a pollution attack which pollutes the watermark embedded in an image with an optimal color noise and hence fools the detector of the public-key watermarking scheme. Furthermore, it applies the proposed attack to public-key subspace watermarking schemes. In our experiments, pirated images are generated by inserting optimal colored signals into watermarked images. As a result, the pirated images are of high quality, but of low detection probability. The experiment results demonstrate that the present pollution attack is very effective.
Evaluation and design of irregular LDPC codes using ACE spectrum
Authors: Dejan Vukobratovic, Vojin Šenk
Venue: IEEE Transactions on Communications (2009)

The construction of finite-length irregular LDPC codes with low error floors is currently an attractive research problem. In particular, for the binary erasure channel (BEC), the problem is to find the elements of selected irregular LDPC code ensembles with the size of their minimum stopping set being maximized. Due to the lack of analytical solutions to this problem, a simple but powerful heuristic design algorithm, the approximate cycle extrinsic message degree (ACE) constrained design algorithm, has recently been proposed. Building upon the ACE metric associated with a cycle in a code graph, we introduce the ACE spectrum of LDPC codes as a useful tool for evaluation of codes from selected irregular LDPC code ensembles. Using the ACE spectrum, we generalize the ACE constrained design algorithm, making it more flexible and efficient. We justify the ACE spectrum approach through examples and simulation results.
Enterprise Knowledge Management Systems: Role of Aspects and Distributed Middleware Framework
Authors: Deepak Dahiya, Usha Batra
Venue: Proceedings of the 2009 Fifth International Joint Conference on INC, IMS and IDC (2009)

The need for an effective management of knowledge is gaining increasing recognition in today’s economy. To acknowledge this fact, new promising and powerful technologies have emerged from industrial and academic research. With these innovations maturing, organizations are more and more willing to adapt such new knowledge management (KM) technologies to improve their knowledge intensive businesses.Therefore, the objectiveof this paperis to address this challenge and introduce a framework for the development ofenterprise knowledge management systems that will support both the business process and the technological knowledge infrastructure. We also discuss in this paper, the role of aspects anddistributedmiddleware framework inenterprise knowledge management systems development.
Stabilizing Policy Improvement for Large-Scale Infinite-Horizon Dynamic Programming
Authors: Michael J. O'Sullivan, Michael A. Saunders
Venue: SIAM Journal on Matrix Analysis and Applications (2009)

Today's focus on sustainability within industry presents a modeling challenge that may be dealt with using dynamic programming over an infinite time horizon. However, the curse of dimensionality often results in a large number of states in these models. These large-scale models require numerically stable solution methods. The best method for infinite-horizon dynamic programming depends on both the optimality concept considered and the nature of transitions in the system. Previous research uses policy improvement to find strong-present-value optimal policies within normalized systems. A critical step in policy improvement is the calculation of coefficients for the Laurent expansion of the present-value for a given policy. Policy improvement uses these coefficients to search for improvements of that policy. The system of linear equations that yields the coefficients will often be rank-deficient, so a specialized solution method for large singular systems is essential. We focus on implementing policy improvement for systems with substochastic classes (a subset of normalized systems). We present methods for calculating the present-value Laurent expansion coefficients of a policy with substochastic classes. Classifying the states allows for a decomposition of the linear system into a number of smaller linear systems. Each smaller linear system has full rank or is rank-deficient by one. We show how to make repeated use of a rank-revealing LU factorization to solve the smaller systems. In the rank-deficient case, excellent numerical properties are obtained with an extension of Veinott's method [Ann. Math. Statist., 40 (1969), pp. 1635-1660] for substochastic systems.
A Mandatory Access Control Model with Enhanced Flexibility
Authors: Yanfang Fan, Zhen Han, Jiqiang Liu, Yong Zhao
Venue: Proceedings of the 2009 International Conference on Multimedia Information Networking and Security - Volume 01 (2009)

The discretionary access control and mandatory access control are two main access control modes which are broadly used in secure operating systems. Discretionary access control is based on user identity and/or groups and mandatory access control is usually based on sensitivity labels. Neither of these two modes can completely satisfy the requirements of all access control. Discretionary access control is too loose to restrict the propagation of privileges while mandatory access control is too rigid to use flexibly. Researchers usually combine two modes by confining discretionary access control in mandatory access control scope such as bell-lapadula model. This brings low flexibility of access control. This paper discusses some examples which can't be handled by traditional mandatory access control based on bell-lapadula model and proposes a new method to integrate the flexibility of discretionary access control with security of mandatory access control. Meanwhile, an exception is defined to enhance the flexibility of the model. The security of the model is analyzed and compared with other relative works.
Universal source controlled channel decoding with nonsystematic quick-look-in turbo codes
Authors: Gil I. Shamir, Kai Xie
Venue: IEEE Transactions on Communications (2009)

Utilization of redundancy left in a channel coded sequence can improve channel decoding performance. Stronger improvement can usually be achieved with nonsystematic encoding. However, nonsystematic codes recently proposed for this problem are not robust to the statistical parameters governing a sequence and thus should not be used without prior knowledge of these parameters. In this work, decoders of nonsystematic quick-look-in turbo codes are adapted to extract and exploit redundancy left in coded data to improve channel decoding performance. Methods, based on universal compression and denoising, for extracting the governing statistical parameters for various source models are integrated into the channel decoder by also taking advantage of the code structure. Simulation results demonstrate significant performance gains over standard systematic codes that can be achieved with the new methods for a wide range of statistical models and governing parameters. In many cases, performance almost as good as that with perfect knowledge of the governing parameters is achievable.