ppxscal/embedding_network huggingface dataset:
Active queue management methods in computer communication networks based on pole placement and h-infinity optimal control
Authors: Qiang Chen
Venue:  (2006)

This thesis studies the control of TCP traffic in the Internet nowadays. Both classical and modern control theory are used to design the controllers for the TCP/AQM system. For the classical control theoretical approaches, we revisit the simple pole placement technique, and exploit this technique to propose four kinds of controllers for active queue management (AQM) in IP routers: the Proportional controller based on Pole Placement (the P_PP controller), the Proportional-plus-integral controller based on Pole Placement (the PI_PP controller), the Self Tuning Proportional controller based on Pole Placement (the ST_P_PP controller), and the Self-Tuning Proportional-plus-Integral controller based on Pole Placement (the ST_PI_PP controller). The transient performance indices---the damping ratio &xi; and the undamped natural frequency &omega;n, are appropriately chosen such that: (a) the transient response of the system is satisfied; (b) all the poles lie in the left-half of the s-plane to guarantee the stability of the system. The self-tuning controllers (the ST_P_PP and the ST_PI_PP) can maintain on-line tuning of the controller parameters so that good system performance can be ensured even under significant load changes. This thesis also investigates the application of a robust modern control technique--- H&infin; optimal control to the AQM controller. Two H&infin; loop-shaping techniques, the S/U Mixed Sensitivity Problem (MSP) and the S/T/U MSP are applied to the controller design. Different weight functions and their impacts on the system performance are discussed and evaluated. Finally, by modeling the uncertainties in the TCP/AQM system in terms of the uncertainty weight, this thesis also designs a robust AQM controller based on a modern control technique---robust &mu; analysis. The controller is synthesized by approximating the &mu;-optimal control problem with the H&infin; S/T/U MSP. The NP (Nominal Performance), the RS (Robust Stability) and the RP (Robust Performance) of the system under the synthesized controller are analyzed using the &mu; analysis technique.
A new stochastic block matching algorithm (SBMA) for video coding based on modified 3-step search
Authors: Sungook Kim
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 04 (1996)

Motion compensated predictive coding is one of the most efficient video coding methods. Full search gives the optimal performance in minimizing the sum of absolute difference (SAD) of pixel values within a block for residual images. We propose a new fast SBMA which exploits spatial and temporal correlations existing in the motion vector field. The new SBMA has a variable search window size and a shiftable search center. Within a given search window, we consider a new search procedure based on a modified 3-step search. Compared to full block matching, we achieve a speed up factor ranging from 70 to 150. As a trade off, we see a 1-12% increase in the error residuals, and the corresponding PSNR value degrades by 0.1-0.5 dB only.
Gold rush: mobile transaction middleware with java-object replication
Authors: Maria A. Butrico, Henry Chang, Anthony Cocchi, Norman H. Cohen, Dennis G. Shea, Stephen E. Smith
Venue: Proceedings of the 3rd conference on USENIX Conference on Object-Oriented Technologies (COOTS) - Volume 3 (1997)

Gold Rush is middleware supporting the writing of Java applications that reside on an intermittently connected mobile client device and access an enterprise database on a central server. While the client is connected to the central server, objects constructed from database entities can be cached in a persistent store on the client. While the client is disconnected, these entities can be manipulated within transactions that are logged on the client. Upon reconnection, the client application can replay these logged transactions to the server, modifying the database. A replayed transaction is checked for conflicts with other database updates that have occurred since the client obtained the input data for the transaction, and the client is notified when such a conflict arises. Communication between the client and the server is optimized to economize the use of a slow or expensive connection such as a radio link.
Presentation schemes for component analysis in IR experiments
Authors: Paul Kantor, Jimmy Lin
Venue: ACM SIGIR Forum (2007)

Information retrieval research, at least as conceived by the SIGIR community, is fundamentally experimental in nature. As such, the presentation of results from controlled, reproducible experiments lies at the core of our work. Many reports follow the same general format: authors propose a new retrieval method, whose performance on some well-defined task is compared against a baseline. Authors also report results from alternative configurations, e.g., variations in parameters, turning off (ablation) of different components, etc. The presentation of experimental results forms an integral part of the conferences and journals that comprise the medium in which knowledge is disseminated.
ADPCM encoding of images using a conjugate gradient based adaptive algorithm
Authors: M. Spann
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 04 (1996)

A new recursive conjugate gradient (RCG) algorithm is developed for two-dimensional (2-D) adaptive differential pulse code modulation (ADPCM). This algorithm is based on the conjugate gradient method of optimization and therefore has a fast convergence characteristic. The RCG operates on samples of data rather than blocks, and is computationally simpler than the recursive least square (RLS) algorithm. Simulation results illustrate the efficiency of the method in ADPCM encoding of images.
FM interference suppression in spread spectrum communications using time-varying autoregressive model based instantaneous frequency estimation
Authors: P. Shan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 05 (1999)

In case of a strong frequency modulated interference in a spread spectrum communication system, the interference can be effectively suppressed by applying a time-varying notch filter with its zero(s) placed at an instantaneous frequency (IF) estimate of the interference. In this paper, we present the use of a time-varying autoregressive model based IF estimator in such a scenario. We model the received signal with an autoregressive model whose coefficients are time-varying and modeled as a combination of a set of known functions of time. The IF of the interference is estimated from the model. It is demonstrated that this method provides superior performance compared to using a time-frequency distribution. The comparison reveals that the Wigner-Ville distribution peak based IF estimator suffers drawbacks such that its filtering gain is limited.
CoLoRaDe: A Novel Algorithm for Controlling Long-Range Dependent Network Traffic
Authors: Karim Mohammed Rezaul, Vic Grout
Venue: Proceedings of the Sixth International Conference on Networking (2007)

Long-range dependence characteristics have been observed in many natural or physical phenomena. In particular, a significant impact on data network performance has been shown in several papers. Congested Internet situations, where TCP/IP buffers start to fill, show long-range dependent (LRD) self-similar chaotic behaviour. The exponential growth of the number of servers, as well as the number of users, causes the performance of the Internet to be problematic since the LRD traffic has a significant impact on the buffer requirements. The Internet is a large-scale, wide-area network for which the importance of measurement and analysis of traffic is vital. The intensity of the long-range dependence (LRD) of communications network traffic can be measured using the Hurst parameter. A variety of techniques (such as R/S analysis, aggregated variance-time analysis, periodogram analysis, Whittle estimator, Higuchi's method, Wavelet-based estimator, absolute moment method, etc.) exist for estimating Hurst exponent but the accuracy of the estimation is still a complicated and controversial issue. Earlier research [1] introduced a novel estimator called the Hurst Exponent from the Autocorrelation Function (HEAF) and it was shown why lag 2 in HEAF (i.e. HEAF (2)) is considered when estimating LRD of network traffic. HEAF estimates H by a process which is simple, quick and reliable. In this research we extend these concepts by introducing a novel algorithm for controlling the long-range dependence of network traffic, named CoLoRaDe which is shown to reduce the LRD of packet sequences at the router buffer.
Verification of Human Decision Models in Military Simulations
Authors: Fei Liu, Ming Yang, Guobing Sun
Venue: Proceedings of the First Asia International Conference on Modelling & Simulation (2007)

Human decision models, often represented as rules or predicates, are key components in most military simulations. Although there exist some verification techniques for rule bases, they are not enough to assure the correctness of human decision models. Based on an analysis of the characteristics of human decision models in military simulations, this paper presents a method for verifying human decision models. A formal description method is developed to describe human decision models, which are automatically mapped to fuzzy Petri nets. A set of formal verification criteria for human decision models are developed, based on which verification is grouped into two classes: weak verification and strong verification. By searching the fuzzy Petri nets, weak verification is implemented, and by reasoning the fuzzy Petri nets, strong verification is implemented.
Fixing Web Sites Using Correction Strategies
Authors: D. Ballis, D. Romero
Venue: Proceedings of the 2nd Int'l. Workshop on Automated Specification and Verification of Web Systems (2006)

The development and the maintenance of Web sites are difficult tasks. To maintain the consistency of ever-larger, complex Web sites, Web administrators need effective mechanisms that aid them in fixing every possible inconsistency. In this paper, we present an extension of a methodology for semi-automatically repairing faulty Web site which we developed in a previous work. As a novel contribution, we define two correction strategies with the aim of increasing the level of automation of our repair method. Specifically, the proposed strategies minimize both the amount of information to be changed and the number of repair actions to be executed in a faulty Web site to make it correct.
Performance analysis of TCP/AQM with generalized AIMD under intermediate buffer sizes
Authors: Do Young Eun, Xinbing Wang
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2007)

For TCP/AQM systems, the issue of buffer sizing has recently received much attention. The classical rule-of-thumb suggests O(N) buffer size to ensure full link utilization when N TCP flows share a bottleneck link of capacity O(N), while recent empirical study shows the buffer of size O(N) is enough to yield high utilization (say, 95%) for large N. However, these results are all limited to the drop-tail scheme and there has been no systematic modeling framework for any buffer sizing between O(N) and O(N). In this paper, we study the limiting behavior of a TCP/AQM system for an intermediate buffer sizing of O(N^@c) (0.5=
Improved universal denominators
Authors: S. A. Abramov, S. P. Polyakov
Venue: Programming and Computing Software (2007)

The paper presents an algorithm for improvement (degree reduction) of universal denominators, which are used, for example, for constructing rational solutions of linear differential and difference systems with polynomial coefficients. A variant of Zeilberger's algorithm is described; it uses construction of universal denominator instead of application of Gosper's algorithm.
Fast and secure distributed read-only file system
Authors: Kevin Fu, M. Frans Kaashoek, David Mazières
Venue: Proceedings of the 4th conference on Symposium on Operating System Design & Implementation - Volume 4 (2000)

Internet users increasingly rely on publicly available data for everything from software installation to investment decisions. Unfortunately, the vast majority of public content on the Internet comes with no integrity or authenticity guarantees. This paper presents the self-certifying read-only file system, a content distribution system providing secure, scalable access to public, read-only data. The read-only file system makes the security of published content independent from that of the distribution infrastructure. In a secure area (perhaps off-line), a publisher creates a digitally-signed database out of a file system's contents. The publisher then replicates the database on untrusted content-distribution servers, allowing for high availability. The read-only file system protocol furthermore pushes the cryptographic cost of content verification entirely onto clients, allowing servers to scale to a large number of clients. Measurements of an implementation show that an individual server running on a 550 Mhz Pentium III with FreeBSD can support 1,012 connections per second and 300 concurrent clients compiling a large software package.
Dynamic function placement for data-intensive cluster computing
Authors: Khalil Amiri, David Petrou, Gregory R. Ganger, Garth A. Gibson
Venue: Proceedings of the annual conference on USENIX Annual Technical Conference (2000)

Optimally partitioning application and filesystem functionality within a cluster of clients and servers is a difficult problem due to dynamic variations in application behavior, resource availability, and workload mixes. This paper presents ABACUS, a run-time system that monitors and dynamically changes function placement for applications that manipulate large data sets. Several examples of data-intensive workloads are used to show the importance of proper function placement and its dependence on dynamic run-time characteristics, with performance differences frequently reaching 2-10X. We evaluate how well the ABACUS prototype adapts to run-time system behavior, including both long-term variation (e.g., filter selectivity) and short-term variation (e.g., multi-phase applications and interapplication resource contention). Our experiments with ABACUS indicate that it is possible to adapt in all of these situations and that the adaptation converges most quickly in those cases where the performance impact is most significant.
The Department of Energy's Technical Leadership Development Program: lessons learned from assessment and evaluation
Authors: M. Murawski
Venue: Proceedings of the 26th Annual Frontiers in Education - Volume 01 (1996)

Beginning in the spring of 1995, the Colorado School of Mines (CSM) contracted to provide an intensive 15-week educational program for interns from the Department of Energy's Technical Leadership Development Program (TLDP). The program, called the "Applied Engineering Fundamentals Course" (AEFC), is designed to help the interns, the "best and the brightest" of the DOE's new hires, to develop their interdisciplinary technical knowledge, teamwork skills, professionalism, communication skills and zest for lifelong learning. As an integral part of the TLDP, we have designed a program to both assess the intents and to evaluate the program being provided by CSM. We have used multiple measures, quantitative and qualitative, formative and summative, to evaluate and assess the course. In this paper, we discuss the unique problems involved in the assessment and evaluation of a program such as the AEFC and the solutions we have developed.
PARAID: a gear-shifting power-aware RAID
Authors: Charles Weddle, Mathew Oldham, Jin Qian, An-I Andy Wang, Peter Reiher, Geoff Kuenning
Venue: Proceedings of the 5th USENIX conference on File and Storage Technologies (2007)

Reducing power consumption for server computers is important, since increased energy usage causes increased heat dissipation, greater cooling requirements, reduced computational density, and higher operating costs. For a typical data center, storage accounts for 27% of energy consumption. Conventional server-class RAIDs cannot easily reduce power because loads are balanced to use all disks even for light loads. We have built the Power-Aware RAID (PARAID), which reduces energy use of commodity server-class disks without specialized hardware. PARAID uses a skewed striping pattern to adapt to the system load by varying the number of powered disks. By spinning disks down during light loads, PARAID can reduce power consumption, while still meeting performance demands, by matching the number of powered disks to the system load. Reliability is achieved by limiting disk power cycles and using different RAID encoding schemes. Based on our five-disk prototype, PARAID uses up to 34% less power than conventional RAIDs, while achieving similar performance and reliability.
Combining Estimates with Planning Poker--An Empirical Study
Authors: Kjetil Molokken-Ostvold, Nils Christian Haugen
Venue: Proceedings of the 2007 Australian Software Engineering Conference (2007)

Combination of expert opinion is frequently used to produce estimates in software projects. However, if, when and how to combine expert estimates, is poorly understood. In order to study the effects of a combination technique called planning poker, the technique was introduced in a software project for half of the tasks. The tasks estimated with planning poker provided: 1) group consensus estimates that were less optimistic than the mechanical combination of individual estimates for the same tasks, and 2) group consensus estimates that were more accurate than the mechanical combination of individual estimates for the same tasks. The set of control tasks in the same project, estimated by individual experts, achieved similar estimation accuracy as the planning poker tasks. However, for both planning poker and the control group, measures of the median estimation bias indicated that both groups had unbiased estimates, as the typical estimated task was perfectly on target.
A Functional Self-Test Approach for Peripheral Cores in Processor-Based SoCs
Authors: A. Apostolakis, M. Psarakis, D. Gizopoulos, A. Paschalis
Venue: Proceedings of the 13th IEEE International On-Line Testing Symposium (2007)

Functional Software-Based Self-Testing (SBST) of mi-croprocessors and processor-based testing of Systems-on-Chip (SoCs) have recently attracted the attention of test technology research community because they provide an effective alternative to other traditional testing and self-testing approaches. SBST allows at-speed functional test-ing of SoC cores with virtually no circuit overhead and limited dependence on external testers. Despite the impor-tance of peripheral control cores in SoCs (in terms of functionality and size), the applicability and limits of SBST on them have not been comprehensively studied. In this paper, we study the effectiveness of SBST on a broad class of communication peripherals. A systematic applica-tion of SBST on two popular peripheral cores (UART and Ethernet) demonstrates the effectiveness of SBST on SoCs with such cores.
Measuring the capacity of a web server
Authors: Gaurav Banga, Peter Druschel
Venue: Proceedings of the USENIX Symposium on Internet Technologies and Systems on USENIX Symposium on Internet Technologies and Systems (1997)

The widespread use of the World Wide Web and related applications places interesting performance demands on network servers. The ability to measure the effect of these demands is important for tuning and optimizing the various software components that make up a Web server. To measure these effects, it is necessary to generate realistic HTTP client requests. Unfortunately, accurate generation of such traffic in a testbed of limited scope is not trivial. In particular, the commonly used approach is unable to generate client request-rates that exceed the capacity of the server being tested even for short periods of time. This paper examines pitfalls that one encounters when measuring Web server capacity using a synthetic workload. We propose and evaluate a new method for Web traffic generation that can generate bursty traffic, with peak loads that exceed the capacity of the server. Finally, we use the proposed method to measure the performance of a Web server.
On the stability of the inverse time-varying prediction error filter obtained with the RWLS algorithm
Authors: R. Lopez-Valcarce
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 03 (1999)

This work provides conditions on the input sequence that ensure the exponential asymptotic stability of the inverse of the forward prediction error filter obtained by means of the recursive weighted least squares algorithm. Note that this filter is in general time-varying. Thus this result is a natural extension to the well-known minimum phase property of forward prediction error filters obtained by the autocorrelation method.
A forensic analysis of a distributed two-stage web-based spam attack
Authors: Daniel V. Klein
Venue: Proceedings of the 20th conference on Large Installation System Administration (2006)

Open mail relays have long been vilified as one of the key vectors for spam, and today - thanks to education and the blocking efforts of open relay databases (ORDBs) - relatively few open relays remain to serve spammers. Yet a critical and widespread vulnerability remains in an as-yet unaddressed arena: web-based email forms. This paper describes the effects of a distributed proxy attack on a vulnerable email form, and proposes easy-to-implement solutions to an endemic problem. Based on forensic evidence, we observed a well-designed and intelligently implemented spam network, consisting of large number of compromised intermediaries that receive instructions from an effectively untraceable source, and which attack vulnerable CGI forms. We also observe that although the problem can be easily mitigated, it will only get worse before it gets better: the vast majority of freely available email scripts all suffer from the same vulnerability; the load on most proxies is relatively very low and hard to detect; and many sites exploited by the compromised proxy machines may never notice that they have been attacked.
Sequential methods for DNA sequencing
Authors: N. M. Haan
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 200. on IEEE International Conference - Volume 02 (2001)

Methods for determining the letters of our genetic code, known as DNA sequencing, currently depend on clever use of electrophoresis to generate data sets indicative of the underlying sequence. Typically the subsequent off-line data processing is carried out less intelligently using a combination of heuristic methods with little mathematical rigour. In this paper, we present a new robust model which is able to accurately predict the effect of the many biological processes which are involved, and moreover, which is usable on-line. Off-line methods have been hampered by the need for processing in as little time as possible after the data is generated; performing the processing on-line has enabled a more advanced algorithm to be used with associated improved performance. The algorithm is framed within a Bayesian probabilistic framework, thereby allowing representation of the random nature of the generative process, and relies on new advances in the burgeoning field of sequential Monte Carlo methods to perform the required highly non-linear filtering and model selection operations.