ppxscal/embedding_network huggingface dataset:
A survey of QoS enhancements for IEEE 802.11 wireless LAN: Research Articles
Authors: Qiang Ni, Lamia Romdhani, Thierry Turletti
Venue: Wireless Communications Mobile Computing (2004)

Quality-of-service (QoS) is a key problem of today's IP networks. Many frameworks (IntServ, DiffServ, MPLS etc.) have been proposed to provide service differentiation in the Internet. At the same time, the Internet is becoming more and more heterogeneous due to the recent explosion of wireless networks. In wireless environments, bandwidth is scarce and channel conditions are time-varying and sometimes highly lossy. Many previous research works show that what works well in a wired network cannot be directly applied in the wireless environment. Although IEEE 802.11 wireless LAN (WLAN) is the most widely used IEEE 802.11 wireless LAN (WLAN) standard today, it cannot provide QoS support for the increasing number of multimedia applications. Thus, a large number of 802.11 QoS enhancement schemes have been proposed, each one focusing on a particular mode. This paper summarizes all these schemes and presents a survey of current research activities. First, we analyze the QoS limitations of IEEE 802.11 wireless MAC layers. Then, different QoS enhancement techniques proposed for 802.11 WLAN are described and classified along with their advantages&#x002F;drawbacks. Finally, the upcoming IEEE 802.11e QoS enhancement standard is introduced and studied in detail. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Polynomial time algorithm for computing the top Betti numbers of semi-algebraic sets defined by quadratic inequalities
Authors: Saugata Basu
Venue: Proceedings of the thirty-seventh annual ACM symposium on Theory of computing (2005)

For any fixed l > 0, we present an algorithm which takes as input a semi-algebraic set, S, defined by P1 ≥ 0,...,Ps ≥ 0, where each Pi ∈ R[X1,...,Xk] has degree ≤ 2, and computes the top l Betti numbers of S, bk-1(S), ..., bk-l(S), in polynomial time. The complexity of the algorithm, stated more precisely, is Σi=0l+2 (si k2O((l,s)). For fixed l, the complexity of the algorithm can be expressed as sl+2 k2O(l), which is polynomial in the input parameters s and k. To our knowledge this is the first polynomial time algorithm for computing non-trivial topological invariants of semi-algebraic sets in Rk defined by polynomial inequalities, where the number of inequalities is not fixed and the polynomials are allowed to have degree greater than one. For fixed s, we obtain by letting l = k, an algorithm for computing all the Betti numbers of S whose complexity is k2O(s)
Classification and taxonomy of TEISMEs
Authors: Charles A. Shoniregun
Venue: Proceedings of the 6th international conference on Electronic commerce (2004)

Small Medium Enterprises (SMEs) are facing dramatic change, often referred to as 'information technology (IT) evolution'. Its magnitude does not seem to be any lesser than the industrial revolution at the start of twentieth century. Advances in information and communication technologies are the main drivers behind this evolution. Explosive popularity of the Internet as a business tool has created a new type of economy, which may be called 'digital economy'. This emerging economy is bringing with it new forms of IT-enabled inter-mediation, on-line businesses, virtual supply chains, rapidly changing internet-eC technologies, increasing knowledge intensity, and unprecedented sensitivity of time-to-market by customers. Although customers are increasingly demanding more value, goods customised to their exact needs, at less cost, and as quickly as possible. To meet these demands, SME needs to innovate new way of creating value and will require different enterprise architectures, different IT infrastructures and different way of thinking about doing business. This transformation of business from old SME to a new agile electronic market and global business is not easy and requires a lot of thinking, planning and investment. This paper discusses the impact of SME definition on the 'Micro' or 'Dot com' business operations in the UK and the classification and taxonomy of TEISME (Technology Enabled Information Small Medium Enterprises). A questionnaire survey was conducted to identify the types of TEISMEs that can be classified under the proposed classification. The question posed by this paper is whether TEISME is complementary to, or indirect competition with SME.
Database concepts used in the LOGOS computer-aided design system
Authors: Robert A. Gingell, Dennis A. Risen, Charles W. Rose
Venue: ACM SIGDA Newsletter (1977)

Some criteria for the database construction of a Computer-Aided Design (CAD) System are specified. These criteria are discussed in terms of the LOGOS CAD system. From the discussion of the LOGOS implementation, a generalized approach to database design for CAD systems is proposed.
Grouping Proof for RFID Tags
Authors: Junichiro Saito, Kouichi Sakurai
Venue: Proceedings of the 19th International Conference on Advanced Information Networking and Applications - Volume 2 (2005)

An RFID tag is a small and cheap device which is combined in IC chip and an antennafor radio communications. The tag is used for management of goods and its distribution. Moreover it reduces the cost of managements of goods. Howevel; an RFID system has some security problems. Juels proposed a "yoking-proof" which guarantees the existence of two tags [2] But we point out that this scheme is not secure against a replay attack. In this paper; we propose a scheme which deals with the problem by using time stamp. Moreovel; we propose a scheme which guarantees the existence of a group of RFID tags.
Zero clustering: an approach to extend zero compression to instruction caches
Authors: Kimish Patel, Enrico Macii, Massimo Poncino
Venue: Proceedings of the 15th ACM Great Lakes symposium on VLSI (2005)

We propose an energy-efficient architecture for instruction caches that relies on dynamic zero compression (DZC), that is, the possibility of reading and writing a single bit for every zero-valued byte [5]. We enhance the basic DZC by using a simple bit permutation to increase the number of zero-valued bytes, so that the corresponding overhead is negligible. The derivation of an effective permutation relies on a heuristic zero clustering algorithm that is based on the knowledge of the memory reference access trace, thus making this solution suitable for application-specific embedded systems. The architecture proposed in this work makes possible the application of zero compression to instruction caches; experiments showed an increase of zero clusters of more than 70% on average, which translates into a 10% improvement in dynamic energy savings with respect to DZC.
Factors affecting effective software quality management revisited
Authors: Nasib S. Gill
Venue: ACM SIGSOFT Software Engineering Notes (2005)

Developing a good software system is a very complex task. In order to produce a good software product, several measures for software quality attributes need to be taken into account. System complexity measurement plays a vital role in controlling and managing software quality because it generally affects the software quality attributes like software reliability, software testability and software maintainability. Thus, software quality assurance (SQA) needs to be addressed keeping in view the new strategies, tool, methodologies and techniques applicable to software development life cycle.This paper is primarily aimed at revisiting and examining peculiar aspects of software development process that affect software quality management process. These aspects of software development process include software reliability measurement, ISO approach applicable to software quality and some aspects related to software testing improvement. Software testing and evaluation methods/tools/techniques do not guarantee effective testing and ensure high software quality. The way to improve the effectiveness of testing is to improve the attitude of software developers towards testing.In this paper, all these factors affecting software quality management have been discussed as well as all the possible improvements have been suggested. The results of this paper may be quite helpful to the researchers in quantifying the specific measuring tools for these software quality attributes.
Performance analysis and evaluation of IEEE 802.11e EDCF: Research Articles
Authors: Jong-Deok Kim, Chong-Kwon Kim
Venue: Wireless Communications Mobile Computing (2004)

Recently, the IEEE 802.11 working group has announced a new distributed access mechanism called Enhanced DCF (EDCF) to provide service differentiation among traffic classes defined as access category. With the increasing demand for supporting Quality of Service (QoS) in IEEE 802.11 wireless LANs, the EDCF is now attracting many researchers' attention due to its practical worth as a standard mechanism. In this paper, we focus on the analytical approach to evaluate the performance of the EDCF. An analytical model is presented to estimate the throughput of the EDCF in saturation (asymptotic) conditions by substantially revising and extending the analytical model developed by Bianchi for the performance analysis of the DCF. Extensive simulation studies based on the NS-2 simulator have been carried out for the validation of the analysis, and they show that it estimates the throughput of the EDCF accurately. By utilizing the analytical model, we evaluate the performance of the EDCF. Specifically, we concentrate on discovering the characteristics of the EDCF parameters, such as CWmin, CWmax and AIFS, in the way that they influence on the performance of the EDCF. Copyright &copy; 2004 John Wiley & Sons, Ltd.
An Identity-Based Signature and Its Threshold Version
Authors: Xiangguo Cheng, Jingmei Liu, Xinmei Wang
Venue: Proceedings of the 19th International Conference on Advanced Information Networking and Applications - Volume 1 (2005)

We propose an identity (ID)-based signature from m-torsion groups of super-singular elliptic curves or hyper-elliptic curves. It is secure against existential forgery under adaptively chosen message and ID attack in the random oracle model. Due to the nice properties of m-torsion groups and Weil pairing, it turns out that the proposed scheme is simple, efficient and has the good property of addition. Based on this ID-based signature scheme, we propose an ID-based threshold signature scheme and show that it has the security properties of unforgeability and robustness.
Block-Diagonal and Constraint Preconditioners for Nonsymmetric Indefinite Linear Systems. Part I: Theory
Authors: Eric de Sturler, Jörg Liesen
Venue: SIAM Journal on Scientific Computing (2005)

We study block-diagonal preconditioners and an efficient variant of constraint preconditioners for general two-by-two block linear systems with zero (2,2)-block. We derive block-diagonal preconditioners from a splitting of the (1,1)-block of the matrix. From the resulting preconditioned system we derive a smaller, so-called related system that yields the solution of the original problem. Solving the related system corresponds to an efficient implementation of constraint preconditioning. We analyze the properties of both classes of preconditioned matrices, in particular their spectra. Using analytical results, we show that the related system matrix has the more favorable spectrum, which in many applications translates into faster convergence for Krylov subspace methods. We show that fast convergence depends mainly on the quality of the splitting, a topic for which a substantial body of theory exists. Our analysis also provides a number of new relations between block-diagonal preconditioners and constraint preconditioners. For constrained problems, solving the related system produces iterates that satisfy the constraints exactly, just as for systems with a constraint preconditioner. Finally, for the Lagrange multiplier formulation of a constrained optimization problem we show how scaling nonlinear constraints can dramatically improve the convergence for linear systems in a Newton iteration. Our theoretical results are confirmed by numerical experiments on a constrained optimization problem.We consider the general, nonsymmetric, nonsingular case. Our only additional requirement is the nonsingularity of the Schur-complement--type matrix derived from the splitting that defines the preconditioners. In particular, the (1,2)-block need not equal the transposed (2,1)-block, and the (1,1)-block might be indefinite or even singular. This is the first paper in a two-part sequence. In the second paper we will study the use of our preconditioners in a variety of applications.
Probabilistic location problems with discrete demand weights
Venue: Networks (2004)

In this article we consider four models for locating a facility on an undirected network with demand weights, which are independent discrete random variables. These problems include the probabilistic versions of two models for locating desirable facilities: the 1-median and 1-minimax problems and two problems for locating undesirable facilities: the 1-antimedian and 1-maximin problems. The article contains analysis of special cases where a solution is determined by solving deterministic versions of the problems and efficient algorithms to solve the problems in general. &copy; 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44&lpar;1&rpar;, 47&ndash;57 2004
Is mathematical software a legitimate research area?
Authors: John R. Rice
Venue: ACM SIGNUM Newsletter (1981)

Recently the chairman of a Computer Science department wrote to solicit my views "regarding the legitimacy of mathematical software development as a research area that can stand by itself". This question arose in that department's deliberations on promotions and tenure and they sensed "a clear split in the numerical analysis community on this question. The opposing view takes the position that mathematical software development is a sub-branch of the area of numerical analysis for which the software is being developed, and is not itself sufficient to establish research credentials for a numerical analyst." The following is my response to this solicitation.
Adaptive index management for future location-based queries
Authors: Hyun Kyoo Park, Jin Hyun Son, Myoung Ho Kim
Venue: Journal of Systems and Software (2005)

Many location-based applications have arisen in various areas including mobile communications, traffic control and military command and control (C2) systems. And one of the important research issue in these areas is tracking and managing moving objects through spatiotemporal indexing for the efficient location-based services. However, managing exact geometric location information is difficult to be achieved due to continual changes of moving objects.Traditionally spatiotemporal index structures focus on optimizing the node accesses during construction and massive updates that do not refer on-line movement updates. In this paper we propose an indexing framework for future location queries based on space partitioning and the dual transformation. Our method provides a constraint database approach for constructing indexes to improve the efficiency of spatiotemporal query answering. In addition, the performance enhancement is achieved by our cost-based dynamic management algorithm that determines the appropriate index reorganization probabilistically induced by various mobility models and query cost functions. This approach can be applied for the predictive range queries on moving object's trajectories specifically in the mobile communication environments. We evaluate our method and compare the performance with the related spatiotemporal index structures in the simulated environments.
Mass Storage System Performance Prediction Using a Trace-Driven Simulator
Authors: Bill Anderson
Venue: Proceedings of the 22nd IEEE / 13th NASA Goddard Conference on Mass Storage Systems and Technologies (2005)

Performance prediction of Mass Storage Systems can be difficult because of the complexity of the systems and the interdependence of the components. This difficulty can lead to over or under provisioned systems and can limit the ability to identify software algorithms (such as cache management or request ordering algorithms) that scale well and yield high performance. Moreover, as Mass Storage Systems scale to a petabyte and beyond, the ability to predict performance could become increasingly important since errors in capacity planning could also grow. This paper discusses a trace-driven discrete event simulator that we have developed to aid us in ranking design and configuration alternatives. The simulator reads in a configuration file, ingests a workload and estimates multiple metrics, including average user response times, cache hit ratios and device utilization. Simulated components include tape drives, disk systems and software components. The simulator has been used to help us determine the size of a disk cache that is used to offload reads from tapes; we found that, for files with sizes under 50 MB, a cache size of around 8 TB can provide a read hit ratio of approximately 67%. The simulator has also been used to estimate the number of STK 9940B tape drives needed to replace our 9840A and 9940A drives. Based on validation runs, we have found that metrics predicted by the simulator are within approximately 20% of the actual values.
K-Optimal Rule Discovery
Authors: Geoffrey I. Webb, Songmao Zhang
Venue: Data Mining and Knowledge Discovery (2005)

K-optimal rule discovery finds the K rules that optimize a user-specified measure of rule value with respect to a set of sample data and user-specified constraints. This approach avoids many limitations of the frequent itemset approach of association rule discovery. This paper presents a scalable algorithm applicable to a wide range of K-optimal rule discovery tasks and demonstrates its efficiency.
A Novel Technique for the Extraction of Depth Information by Gradient Analysis on Grayscale Images
Authors: Li Tao, Vijayan Asari
Venue: Proceedings of the 33rd Applied Imagery Pattern Recognition Workshop (2004)

A technique specifically designed for 3D surface reconstruction of human face in a single grayscale image was developed based on the principle of Shape from Shading (SFS). Lambertian reflectance model was used to obtain the surface gradient information contained in the intensity image. The surface depth was computed by direct integration of surface gradients. The X and Y components of surface gradients were determined based on the assumption that the direction of surface gradient is parallel to the image intensity gradient. In order to determine the signs of the X and Y components of surface gradients, the analysis of image intensity and face detection technique were used to provide the position of critical points based on the 3D characteristics of human face. This algorithm has been applied to synthetic face images with light source direction along z axis, and the reconstructed 3D human face was obtained with good accuracy and high speed. The result produced by our algorithm was also compared with those of other SFS algorithms. The performance of the proposed algorithm indicates that the new concept of combining face detection with SFS will be a promising and useful technique for recovering 3D faces from grayscale images.
Computer-related technostress in China
Authors: Qiang Tu, Kanliang Wang, Qin Shu
Venue: Communications of the ACM (2005)

Technostress has been defined as any negative effect on human attitudes, thoughts, behavior, and psychology that directly or indirectly results from technology [8]. With the recent widespread application of IT and the Internet throughout China, technostress has become a serious issue for both users and IT professionals due to its potential effect on users' mental health and on-the-job productivity. Chinese employees are surrounded, often overwhelmed, by modern technology. The top 100 largest Chinese enterprises, accounting for 25% of China's GDP, are investing heavily ($10--$15 billion annually) in new IT applications, including enterprise resource planning systems. A 2002 report by the Chinese Ministry of Information Industry stated that there are 380 million mobile phone subscribers in China, making the country the world's largest mobile phone market. And a survey conducted in 2004 by the China Internet Network Information Center found that 87 million Chinese frequently accessed the Internet in 2004, an increase of 19 million, or 27.9%, over 2003.
The processing of Portuguese based upon logic: LNEC, Centro de Informatica, Lisboa, Portugal
Authors: Helder Coelho
Venue: Issue 79 (January 1982) (1982)

The objective of this research program, under progress, is the development of feasible methods for consulting and creating databases
Parallel Implementation of Density Functional Theory within the Real Space Pseudopotential Approach
Authors: Eugene S. Kadantsev, M. J. Stott
Venue: Proceedings of the 19th International Symposium on High Performance Computing Systems and Applications (2005)

This paper describes a parallel implementation of total energy Density Functional Theory (DFT) within the real space pseudopotential approach. Our parallel implementation is based on a public domain serial real space pseudopotential code Octopus developed by M. A. L. Marques, A. Castro, G. F. Bertsch, and A. Rubio [1]. In the real space pseudopotential approach, the quantities of interest such as single-particle orbitals are expanded on a 3D uniform grid, the differential operators are computed using high-order finite-difference formulas, and the electron-ion interaction is described by first-principles pseudopotentials. The parallelism is achieved by partitioning the real space grid into subdomains which are allocated to computer processors. The partitioning scheme employed in our implementation and the communications involved, along with tests of the scalability of the code are discussed.
Efficient Array & Pointer Bound Checking Against Buffer Overflow Attacks via Hardware/Software
Authors: Zili Shao, Chun Xue, Qingfeng Zhuge, Edwin H. -M. Sha, Bin Xiao
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume I - Volume 01 (2005)

Buffer overflow attacks cause serious security problems. Array & pointer bound checking is one of the most effective approaches for defending against buffer overflow attacks when source code is available. However, original array & pointer bound checking causes too much overhead since it is designed to catch memory errors and it puts too many checks. In this paper, we propose an efficient array & pointer bound checking strategy to defend against buffer overflow attacks. In our strategy, only the bounds of write operations are checked. We discuss the optimization strategy via hardware/software and conduct experiments. The experimental results show that our strategy can greatly reduce the overhead of array & pointer bound checking. Our conclusion is that based on our strategy, array & pointer bound checking can be a practical solution for defending systems against buffer overflow attacks with tolerable overhead.