ppxscal/embedding_network huggingface dataset:
Exploring Inter-Module Relationships in Evolving Software Systems
Authors: Mircea Lungu, Michele Lanza
Venue: Proceedings of the 11th European Conference on Software Maintenance and Reengineering (2007)

Many of the existing approaches to reverse architecting "the reverse engineering of the architecture of software systems" are based on software exploration tools which provide interactive ways of exploring the system. These tools start with high-level views of the system and refine them with drill-down techniques applied on the high-level entities such as modules and packages, leaving aside valuable information contained in the dependencies between them. In this article we argue that the visualization of inter-module relations bears great potential for supporting the understanding of large evolving software systems. We present two concrete examples of such visualizations. The first, The Semantic Dependency Matrix is a technique for displaying details about a dependency between two modules which groups together classes with similar behavior. The second, The Edge Evolution Filmstrip presents the evolution of an inter-module relation through multiple versions of the system. Based on our experience with the Edge Evolution Film Strip, we propose a pattern language for inter-module relationships. We exemplify both the visualizations and the pattern language with examples from two large open source software systems.
Regularization approach to direction estimation of coherent narrow-band signals
Authors: J. Xin
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

This paper addresses the problem of estimating the directions of coherent narrow-band signals impinging on a uniform linear array when the number of signals is unknown. By incorporating the linear prediction (LP) model with a subarray scheme, the directions of coherent signals can be estimated from the zeros of the corresponding prediction polynomial. To obtain a reliable estimation of the LP coefficients, we introduce multiple regularization parameters into the corrected least squares (CLS) estimation. The analytical expressions of the mean-squares-error (MSE) of the regularized CLS estimate and the optimal regularization parameters are derived. It is clarified that the number of signals can be determined by comparing the optimal parameters with the eigenvalues. An iterative regularization algorithm is developed for direction estimation without any a priori knowledge, where the number of coherent signals and the noise variance are estimated from the noisy data simultaneously.
Coordinated control for networked multi-agent systems
Authors: Richard M. Murray
Venue:  (2007)

Coordination in networked multi-agent systems attracts significant interest in the realm of engineering. Typical examples include formations of unmanned aerial vehicles, automated highway systems, and sensor networks. One common feature for these systems is that coordinated behaviors are exhibited by interactions among agents where information exchange and manipulation are necessary. In this work, three relevant issues are investigated in detail: uniform strategy for multi-agent formation control, fast-converging consensus protocols, and packet-based state estimation over communication networks. Formation control of multi-agent systems involves harmony among local controller design, interaction topology analysis, and objective agreement among networked agents. We propose a novel control strategy so that each agent responds to neighbors' behaviors as well as acts towards the global goal. Using the tools from signal flow graphs and algebraic graph theory, we show that this new strategy eases the design of local controllers. Robustness against the link failure and scalable disturbance resistance are also discussed based on small-gain theory.Consensus protocols over communication networks are used to achieve agreement among agents. One important issue is the convergence speed. We propose multi-hop relay protocols for fast consensus seeking. Without physically changing the topology of the communication network, this type of distributed protocol increases the algebraic connectivity by employing multi-hop paths in the network. We also investigate the convergence behaviors of consensus protocols with communication delays.Efficiently estimating the states of other agents over communication links is also discussed in this work. When information flows in the network, packet-based data is normally not retransmitted in order to satisfy real-time requirements. Thus, packet drops and random delays are inevitable. We introduce multiple description source codes to manipulate the data before transmission. Using modified algebraic Riccati equations, we show that multiple description codes improve the performance of Kalman filters over a large set of packet-dropping scenarios. This problem is also generalized to the case where observation data has an independent and identical static distribution over a finite set of observation noise. Moreover, Kalman filtering with bursty packet drops is also discussed based on the two-state Markov chain model.
Dynamics of global supply chain and electric power networks: models, pricing analysis, and computations
Authors: Anna Nagurney
Venue:  (2006)

In this dissertation, I develop a new theoretical framework for the modeling, pricing analysis, and computation of solutions to electric power supply chains with power generators, suppliers, transmission service providers, and the inclusion of consumer demands. In particular, I advocate the application of finite-dimensional variational inequality theory, projected dynamical systems theory, game theory, network theory, and other tools that have been recently proposed for the modeling and analysis of supply chain networks (cf. Nagurney (2006)) to electric power markets. This dissertation contributes to the extant literature on the modeling, analysis, and solution of supply chain networks, including global supply chains, in general, and electric power supply chains, in particular, in the following ways. It develops a theoretical framework for modeling, pricing analysis, and computation of electric power flows/transactions in electric power systems using the rationale for supply chain analysis. The models developed include both static and dynamic ones. The dissertation also adds a new dimension to the methodology of the theory of projected dynamical systems by proving that, irrespective of the speeds of adjustment, the equilibrium of the system remains the same. Finally, I include alternative fuel suppliers, along with their behavior into the supply chain modeling and analysis framework. This dissertation has strong practical implications. In an era in which technology and globalization, coupled with increasing risk and uncertainty, complicate electricity demand and supply within and between nations, the successful management of electric power systems and pricing become increasingly pressing topics with relevance not only for economic prosperity but also national security. This dissertation addresses such related topics by providing models, pricing tools, and algorithms for decentralized electric power supply chains. This dissertation is based heavily on the following coauthored papers: Nagurney, Cruz, and Matsypura (2003), Nagurney and Matsypura (2004, 2005, 2006), Matsypura and Nagurney (2005), Matsypura, Nagurney, and Liu (2006).
Channel estimation for multicarrier CDMA
Authors: U. Tureli
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

Multicarrier CDMA (MC-CDMA) is a flexible and adaptable radio interface to provide dynamically changing bit rates and a variety of services on radio channels. An accurate channel estimate allows the use of multiuser detection and power loading to improve system performance. A blind linear multiuser channel estimator for MC-CDMA is proposed. Unlike the time varying spreading code or information bearing sequence, the channel is stationary over long time intervals. This fact is exploited in a new method for simultaneous estimation of the channel impulse response vector of multiple users. The complexity of the derived channel estimator can be reduced at the expense of accuracy. It is shown by computer simulation that the proposed method performs well under different scenarios.
Bifurcation from infinity and multiple solutions for some discrete Sturm-Liouville problems
Authors: Ruyun Ma
Venue: Computers Mathematics with Applications (2007)

In this paper, we study nonlinear discrete boundary value problems of the form @D[p(t-1)@Dy(t-1)]+q(t)y(t)+(@l"k+@l)y(t)+f(t,y(t))=h(t),t@?T,a"1"1y(a)+a"1"2@Dy(a)=0,a"2"1y(b+1)+a"2"2@Dy(b+1)=0, where @l"k is an eigenvalue of the associated linear problem, @l is a parameter, and f satisfies the sublinear growth condition |f(t,s)|@?A|s|^@a+B,t@?{a+1,...,b+1},s@?R for some 0@?@a
The Influence of Relations among Different Levels of UML Diagrams onto Software Maintenance
Authors: Dariusz Dymek, Leszek Kotulski
Venue: Proceedings of the 2nd International Conference on Dependability of Computer Systems (2007)

UML represents the current state of the software model with the help of 13 types of diagrams. The methodology of modeling is usually described as a process of reasoning new properties of these diagrams on the base of their previous versions. There is not, however any formal support of remembering the trace of this reasoning process. The introduction of the vertical relation, showing how an element of one type of a diagram has influenced the creation of some elements belonging to other diagrams, seems to be very useful for software maintenance. The paper discusses the problem of such a vertical relation construction with the help of graph transformations. It shows its utility from technical and business perspective.
Quantization noise analysis of wave digital and lossless digital integrator allpass/lattice filters
Authors: J. Holmberg
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 03 (1999)

Quantization noise levels of two low-sensitive allpass filter structures, namely wave digital circulator filters (WDCF) and lossless digital integrator filters (LDIF), are compared. Allpass filters are of interest for design of lowpass and bandpass lattice filters. The results show, primarily, that second-order LDIFs have lower total quantization noise gains than corresponding WCDFs for any pole configuration within the right half-circle of the z plane. The benefit of using ladder LDIFs rather than cascaded first and second order sections is also demonstrated.
Data Hiding in SIM/USIM Cards: A Steganographic Approach
Authors: Antonio Savoldi, Paolo Gubian
Venue: Proceedings of the Second International Workshop on Systematic Approaches to Digital Forensic Engineering (2007)

The aim of this paper is twofold. First, the real structure of a SIM/USIM card filesystem will be presented, analyzing what is valuable from a forensics perspective and showing what evidence is not detectable and extractable with the tools present in the arena of open-source and proprietary software. After that, the paper will focus on a framework that can be used to detect and extract the so-called nonstandard part of a SIM/USIM filesystem, which is a concealed part usable also to store arbitrary and sensitive information. As a proof-of-concept, an interesting example will be presented on the methods usable to obtain the data hiding in an ordinary SIM/USIM card.
A distributed file system for a wide-area high performance computing infrastructure
Authors: Edward Walker
Venue: Proceedings of the 3rd conference on USENIX Workshop on Real, Large Distributed Systems - Volume 3 (2006)

We describe our work in implementing a wide-area distributed file system for the NSF TeraGrid. The system, called XUFS, allows private distributed name spaces to be created for transparent access to personal files across over 9000 computer nodes. XUFS builds on many principles from prior distributed file systems research, but extends key design goals to support the workflow of computational science researchers. Specifically, XUFS supports file access from the desktop to the wide-area network seamlessly, survives transient disconnected operations robustly, and demonstrates comparable or better throughput than some current high performance file systems on the wide-area network.
Statement Merge: An Inter-Statement Optimization of Array Language Programs
Authors: Dz-ching R. Ju, Chuan-lin Wu, Paul Carini
Venue: Proceedings of the 1994 International Conference on Parallel Processing - Volume 02 (1994)

Array language provides an effective paradigm for developing portable parallel programs but will only be used if compilers generate efficient code for array operations this paper presents an inter-statement optimization technique which merges related array operations in different statements. A merged statement creates opportunities for previously developed inter-primitive optimizations of array operators The potential advantages of statement merge are the elimination of a program variable, demand driven evaluation, reductions of data movement and loop overhead. The combination of statement merge and inter-primitive optimizations achieves a 3 8 fold execution time speedup in a scientific application
Academic excellence for minority engineering students
Authors: M. R. Anderson-Rowland, M. A. McCartney, M. A. Reyes
Venue: Proceedings of the Frontiers in Education Conference on 1995. Proceedings., 1995 vol 1. - Volume 01 (1995)

The goal of the Office of Minority Engineering Programs (OMEP) at Arizona Stare University (ASU) is to build a climate that develops not only academic excellence, but, also, provide experiences for students that will build self esteem, competence, and flexible and marketable skills that will sustain them through the twenty first century. Comprehensive approaches to the development of engineering strategies are most often created not in isolation, but through collaborative, team building strategies. OMEP has the challenge of preparing students to meet the changing industry climate. Therefore, a program was called for that could reinforce engineering concepts in a team setting to improve academic excellence. Supported by the Foundation Coalition, the OMEP has now begun an Academic Excellence Program that clusters under represented minority (African American Hispanic and Native American) students enrolled in ECE 100, a course designed to teach engineering concepts and computer skills. Non minority students in the course are also invited to participate in these workshops. The students develop their own community of learners and collectively come to conclusions on how to process information. The Academic Excellence Workshops help to move away from traditional tutoring that is often a short term fix. Rather, these sessions enhance the mastery of engineering concepts as opposed to isolated problems. We feel this process prepares students for potential curriculum integration in the future, as well as for team participation in industry.
A 100-dB gain-corrected delta-sigma audio DAC with headphone driver
Authors: Ruopeng Wang, Sang-Ho Kim, Sang-Hyeon Lee, Seung-Bin You, Jae-Whui Kim, Un-Ku Moon, Gabor C. Temes
Venue: Analog Integrated Circuits and Signal Processing (2007)

An oversampled digital-to-analog converter (DAC) with a 100-dB A-weighted dynamic range is presented. It uses a switched-capacitor (SC) array to transfer the sampled charges directly into the headphone driver. The overall DAC gain is precisely controlled by a novel reference stage. A new dynamic element matching algorithm, based on split-set data-weighted averaging (SDWA), is used to improve the dynamic range and to reduce the nonlinearity caused by mismatches in the multibit DAC.
AlouetteCanada metadata toolkit
Authors: Mark Jordan
Venue: Proceedings of the 7th ACM/IEEE-CS joint conference on Digital libraries (2007)

This poster provides an overview of the AlouetteCanada Metadata Toolkit.
IP only server
Authors: Muli Ben-Yehuda, Oleg Goldshmidt, Elliot K. Kolodner, Zorik Machulsky, Vadim Makhervaks, Julian Satran, Marc Segal, Leah Shalev, Ilan Shimony
Venue: Proceedings of the annual conference on USENIX '06 Annual Technical Conference (2006)

Present day servers must support a variety of legacy I/O devices and protocols that are rarely used in the day to day server operation, at a significant cost in board layout complexity, reliability, power consumption, heat dissipation, and ease of management. We present a design of an IP Only Server, which has a single, unified I/O interface: IP network. All of the server's I/O is emulated and redirected over IP/Ethernet to a remote management station, except for the hard disks which are accessed via iSCSI. The emulation is done in hardware, and is available from power-on to shutdown, including the pre-OS and post-OS (crash) stages, unlike alternative solutions such as VNC that can only function when the OS is operational. The server's software stack -- the BIOS, the OS, and applications -- will run without any modifications. We have developed a prototype IP Only Server, based on a COTS FPGA running our embedded I/O emulation firmware. The remote station is a commodity PC running a VNC client for video, keyboard and mouse. Initial performance evaluations with unmodified BIOS and Windows and Linux operating systems indicate negligible network overhead and acceptable user experience. This prototype is the first attempt to create a diskless and headless x86 server that runs unmodified industry standard software (BIOS, OS, and applications).
A Novel Early DBA Mechanism with Prediction-Based Fair Excessive Bandwidth Reallocation Scheme in EPON
Authors: I-Shyan Hwang, Zen-Der Shyu, Liang-Yu Ke, Chun-Che Chang
Venue: Proceedings of the Sixth International Conference on Networking (2007)

In this paper, we propose a novel Early dynamic bandwidth allocation (E-DBA) mechanism incorporated with a prediction-based fair excessive bandwidth reallocation (PFEBR) scheme in EPON. The E-DBA mechanism not only can reduce the idle period in the traditional DBA mechanism, but also provide more accurate prediction for the PFEBR scheme to ensure the fairness of all ONUs and improve the overall system performance. The proposed prediction model for different traffic classes is based on the variation of traffic for all ONUs in EPON. The simulation results show that the proposed E-DBA mechanism with PFEBR scheme can improve the system performance of well-known DBA algorithms.
A Technique for Representing Multiple Output Binary Functions with Applications to Verification and Simulation
Authors: Abusaleh Jabir, Dhiraj Pradhan, T. L. Rajaprabhu, A. K. Singh
Venue: IEEE Transactions on Computers (2007)

This paper presents a technique for representing multiple output binary and word-level functions in GF(N) ($N=p^m$, p a prime number and m a nonzero positive integer) based on decision diagrams (DD). The presented DD is canonical and can be made minimal with respect to a given variable order. The DD has been tested on benchmarks including integer multiplier circuits and the results show that it can produce better node compression (more than an order of magnitude in some cases) compared to shared BDDs. The benchmark results also reflect the effect of varying the input and output field sizes on the number of nodes. Methods of graph-based representation of characteristic and encoded characteristic functions in GF(N) are also presented. Performance of the proposed representations has been studied in terms of average path lengths and the actual evaluation times with 50,000 randomly generated patterns on many benchmark circuits. All these results reflect that the proposed technique can out perform existing techniques.
Ranking of Optical Character Prototypes in a Large Database Using Isothetic Chord Lengths
Authors: Partha Bhowmick, Arindam Biswas, Bhargab B. Bhattacharya
Venue: Proceedings of the International Conference on Computing: Theory and Applications (2007)

A novel algorithm for conferring a ranking system on the prototypes of a large database of optical/handwritten characters is proposed. The ranking system is designed using the (isothetic) chord lengths of the enclosing isothetic polygons corresponding to the prototypes, for a prescribed grid-size. As the derivation of structural information of a character by thinning or by edge detection is susceptible to its impurity during imaging or post-processing, an isothetic polygon is used that captures the geometric structure of the character in an elegant way. The proposed scheme has a striking potential in deciding the relative merit and usefulness of a particular prototype with respect to the other prototypes of the corresponding character in the concerned database. Several quantitative measures have been suggested, and supporting experimental results have been reported, which justify the strength and efficiency of the proposed method.
Generic congestion control through network coordination
Authors: Xicheng Liu, C. Cheung, J. S. Baras
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 02 (2002)

With the rapid emergence of new services and the quick change of traffic in Internet, the widely used end-to-end congestion control scheme becomes insufficient. This paper proposes a new congestion control architecture based on the coordination among the core router the edge router, and the host. The core router notifies its immediately upstream nodes when it detects incipient congestion. Those nodes then constrain their sending rates to prevent congestion. No per-flow state information is maintained in routers. The application itself need not take care of the rate adaptation. The architecture provides a uniform solution accommodating both responsive and unresponsive traffic with trivial overhead. It reduces the packet loss to zero, and leads to higher network resource utilization. Response time to congestion is greatly reduced. The architecture has been implemented in the Linux kernel, Some preliminary experiments show its advantages.
Teaching pre-calculus students electrical engineering principles using low cost hardware
Authors: Yongmian Zhang
Venue: Proceedings of the Frontiers in Education Conference, 2001. 31st Annual - Volume 02 (2001)

Using low cost hardware and the Visual Basic programming language, the authors have developed teaching modules which can effectively introduce basic science and technology principles at several levels from high school to freshman Electrical Engineering. They have tested these methods in a NSF sponsored course designed to teach high school teachers how to introduce science and technology to their students. To illustrate how the software tool and inexpensive hardware can be used to aid learning and teaching electrical and computer engineering concepts in the classroom, the authors present example experiments.