ppxscal/embedding_network huggingface dataset:
Performance evaluation of optical mesh restoration schemes
Authors: Sunggy Koo, Suresh Subramaniam
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

This paper investigates the performance of various schemes for restoration of lightpaths in an optical mesh network. We consider schemes in which backup paths for links or paths are pro-computed, but wavelength assignment is either pro-computed (static) or done dynamically upon failure (dynamic). In static restoration we compare the performance of link and path restoration in terms of capacity requirement and restoration time. For the dynamic restoration, we consider several dynamic wavelength reservation schemes such as backward and forward reservation with different portion of wavelength to be reserved in both directions. Their performance is evaluated in terms of restoration speed and restorability. Simulation results indicate that path protection requires less capacity than link protection for 100% restorability, and dynamic restoration with backward wavelength reservation shows better restorability than static restoration schemes, when the extra capacity is relatively small. Forward wavelength reservation shows faster restoration speed with lower restorability than the backward wavelength reservation. In general, the optimal restoration scheme depends on extra capacity available and restoration time limit.
XDuce: A statically typed XML processing language
Authors: Haruo Hosoya, Benjamin C. Pierce
Venue: ACM Transactions on Internet Technology (TOIT) (2003)

XDuce is a statically typed programming language for XML processing. Its basic data values are XML documents, and its types (so-called regular expression types) directly correspond to document schemas. XDuce also provides a flexible form of regular expression pattern matching, integrating conditional branching, tag checking, and subtree extraction, as well as dynamic typechecking. We survey the principles of XDuce's design, develop examples illustrating its key features, describe its foundations in the theory of regular tree automata, and present a complete formal definition of its core, along with a proof of type safety.
A precorrected-FFT method for simulating on-chip inductance
Authors: Haitian Hu, David T. Blaauw, Vladimir Zolotov, Kaushik Gala, Min Zhao, Rajendran Panda, Sachin S. Sapatnekar
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

The simulation of on-chip inductance using PEEC-based circuit analysis methods often requires the solution of a subproblem where an extracted inductance matrix must be multiplied by a current vector, an operation with a high computational cost. This paper presents a highly accurate technique, based on a precorrected-FFT approach, that speeds up this calculation. Instead of computing the inductance matrix explicitly, the method exploits the properties of the inductance calculation procedure while implicitly considering the effects of all of the inductors in the layout. An optimized implementation of the method has been applied to accurately simulate large industrial circuits with up to 121,000 inductors and nearly 7 billion mutual inductive couplings in about 20 minutes. Techniques for trading off the CPU time with the accuracy using different approximation orders and grid constructions are also illustrated. Comparisons with a block diagonal sparsification method in terms of accuracy, memory and speed demonstrate that our method is an excellent approach for simulating on-chip inductance in a large circuit.
An Integer L-Shaped Algorithm for the Capacitated Vehicle Routing Problem with Stochastic Demands
Authors: Gilbert Laporte, François V. Louveaux, Luc van Hamme
Venue: Operations Research (2002)

The classical Vehicle Routing Problem consists ofdetermining optimal routes form identical vehicles, starting and leaving at the depot, such that every customer is visited exactly once. In the capacitated version (CVRP) the total demand collected along a route cannot exceed the vehicle capacity. This article considers the situation where some ofthe demands are stochastic. This implies that the level of demand at each customer is not known before arriving at the customer. In some cases, the vehicle may thus be unable to load the customer's demand, even ifthe expected demand along the route does not exceed the vehicle capacity. Such a situation is referred to as a failure. The capacitated vehicle routing problem with stochastic demands (SVRP) then consists ofminimizing the total cost ofthe planned routes and of expected failures. Here, penalties for failures correspond to return trips to the depot. The vehicle first returns to the depot to unload, then resumes its trip as originally planned. This article studies an implementation of the IntegerL-shaped method for the exact solution of the SVRP. It develops new lower bounds on the expected penalty for failures. In addition, it provides variants of the optimality cuts for the SVRP that also hold at fractional solutions. Numerical experiments indicate that some instances involving up to 100 customers and few vehicles can be solved to optimality within a relatively short computing time.
Coding in tongues: a bilingual programming perspective to data structures
Authors: Brian Tjaden, Hannah Tang
Venue: Journal of Computing Sciences in Colleges (2003)

Many upper level computer science courses consist of students with diverse backgrounds in disparate programming languages. This can result when students enrolled in a course have varying academic or professional experience, or in the wake of a programming language transition in CS1 and CS2 courses from one language to another. This language transition in introductory courses has occurred at many schools in recent years, and many others anticipate a transition in the near future. In this paper, we describe our experiences in one such course, a third term Data Structures course, in which students had diverse programming language backgrounds. Rather than choose one language to compel students to use, we encouraged students to decide for themselves which language they found most appropriate. This approach seeded a theme we developed throughout the course, that there are multiple solutions to any problem, including determining the most appropriate language in which to implement a program. We describe the challenges we faced in this course as well as investigate some of the advantages and disadvantages of this method, and we provide some anecdotal examples for dealing with programming language diversity in the classroom setting.
Fabrication of sub- 10-nm Au-Pd structures using 30 keV electron beam lithography and lift-off
Authors: F. Lehmann, G. Richter, T. Borzenko, V. Hock, G. Schmidt, L. W. Molenkamp
Venue: Microelectronic Engineering (2003)

We report the fabrication of 6-nm Au-Pd structures using 30-keV e-beam lithography in a standard double-layer poly(methylmethacrylate) resist on silicon and subsequent lift-off. Line arrays with periods as small as 27 nm were realized. Details of the processing are presented and the dependence of the resolution on the different resist layer thicknesses is discussed.
Information technology education one state's experience
Authors: William Mitchell
Venue: Journal of Computing Sciences in Colleges (2002)

In past few years computing educators have witnessed (a) a call for a broader discipline called Information Technology rather than Computer Science [1,2,3], (b) the development of a new model curriculum for Computer Science [4], (c) a near crises in the supply of computer people at all levels, driving up salaries and spurring blue-ribbon reports [5,6,7,8] and new Federal and state programs [9,10], and (d) the formation of new colleges of technology all across the country [11]. The author is participating in one of these new colleges and is helping to forge a new approach to information technology education that will better serve a small state. This paper discusses the issues that all IT colleges face and outlines the strategy that is being implemented in Arkansas, a strategy that is perhaps applicable to other states across the nation and that could be incorporated by many smaller colleges.
On the large deviations approximation for the stationary distribution of skip-free regulated queueing networks
Authors: Florin Avram
Venue: Performance Evaluation (2003)

Large deviations papers like that of Ignatyuk et al. [Russ. Math. Surv. 49 (1994) 41-99] have shown that asymptotically, the stationary distribution of homogeneous regulated networks is of the form P{X(t) ≈ n} ≈ K e-αn with the coefficient α being different in various "boundary influence domains" and also depending on some of these domains on n. In this paper, we focus on the case of constant exponents α and on a subclass of networks we call "strongly skip-free" (which includes all Jackson and all two-dimensional skip-free networks). We conjecture that an asymptotic exponent α is constant iff it corresponds to a large deviations escape path which progresses gradually (from the origin to the interior) through boundary facets whose dimension always increases by one. Solving the corresponding large deviations problem for our subclass of networks leads to a family of "local large deviation systems" (LLDSs) (for the constant exponents), which are expressed entirely in terms of the cumulant generating function of the network. In this paper, we show that at least for "strongly skip-free" Markovian networks with independent transition processes, the LLDS is closely related to some "local boundary equilibrium systems" (LESs) obtained by retaining from the equilibrium equations only those valid in neighborhoods of the boundary.Since asymptotic results require typically only that the cumulant generating function is well-defined over an appropriate domain, it is natural to conjecture that these LLDSs will provide the asymptotic constant exponents regardless of any distributional assumptions made on the network.Finally, we outline a practical recipe for combining the local approximations to produce a global large deviations approximation P{Xt ≈ n} ≈ Σj Kj e-α(j)n, with the coefficients Kj determined numerically.
Implementing relevance feedback in the Bayesian network retrieval model
Authors: Luis M. de Campos, Juan M. Fernández-Luna, Juan F. Huete
Venue: Journal of the American Society for Information Science and Technology (2003)

Relevance Feedback consists in automatically formulating a new query according to the relevance judgments provided by the user after evaluating a set of retrieved documents. In this article, we introduce several relevance feedback methods for the Bayesian Network Retrieval Model. The theoretical frame on which our methods are based uses the concept of partial evidences, which summarize the new pieces of information gathered after evaluating the results obtained by the original query. These partial evidences are inserted into the underlying Bayesian network and a new inference process (probabilities propagation) is run to compute the posterior relevance probabilities of the documents in the collection given the new query. The quality of the proposed methods is tested using a preliminary experimentation with different standard document collections.
A formal theory of fuzzy natural language quantification and its role in granular computing
Authors: Ingo Glöckner, Alois Knoll
Venue: Granular computing: an emerging paradigm (2001)

Fuzzy quantification is a linguistic granulation technique capable of expressing the global characteristics of a collection of individuals, or a relation between individuals, through meaningful linguistic summaries. However, existing approaches to fuzzy quantification fail to provide convincing results in the important case of two-place quantification (e.g. "many blondes are tall"). We develop an axiomatic framework for fuzzy quantification which complies with a large number of linguistically motivated adequacy criteria. In particular, we present the first models of fuzzy quantification which provide an adequate account of the "hard" cases of multiplace quantifiers, non-monotonic quantifiers, and non-quantitative quantifiers, and we show how the resuiting operators can be efficiently implemented based on histogram computations.
Compacting sequences with invariant transition frequencies
Authors: Ali Pinar, C. L. Liu
Venue: ACM Transactions on Design Automation of Electronic Systems (TODAES) (2003)

Simulation-based power estimation is commonly used for its high accuracy despite excessive computation times. Techniques have been proposed to speed it up by compacting an input sequence while preserving its power-consumption characteristics. We propose a novel method to compact a sequence that preserves transition frequencies. We prove the problem is NP-complete, and propose a graph model to reduce it to that of finding a heaviest-weighted trail, and a heuristic utilizing this model. We also propose using multiple sequences for better accuracy with even shorter sequences. Experiments show that power dissipation can be estimated with an error of only 2.3&percnt;, while simulation times are reduced by 10. Proposed methods generate solutions that effectively preserve transition frequencies and that are very close to optimal. Experiments also show that multiple sequences grant more accurate results with even shorter sequences.
Convergent scheduling
Authors: Walter Lee, Diego Puppin, Shane Swenson, Saman Amarasinghe
Venue: Proceedings of the 35th annual ACM/IEEE international symposium on Microarchitecture (2002)

Convergent scheduling is a general framework for cluster assignment and instruction scheduling on spatial architectures. A convergent scheduler is composed of independent passes, each implementing a heuristic that addresses a particular problem or constraint. The passes share a simple, common interface that provides spatial and temporal preference for each instruction. Preferences are not absolute; instead, the interface allows a pass to express the confidence of its preferences, as well as preferences for multiple space and time slots. A pass operates by modifying these preferences. By applying a series of passes that address all the relevant constraints, the convergent scheduler can produce a schedule that satisfies all the important constraints. Because all passes are independent and need to understand only one interface to interact with each other, convergent scheduling simplifies the problem of handling multiple constraints and codeveloping different heuristics. We have applied convergent scheduling to two spatial architectures: the Raw processor and a clustered VLIW machine. It is able to successfully handle traditional constraints such as parallelism, load balancing, and communication minimization, as well as constraints due to preplaced instructions, which are instructions with predetermined cluster assignment. Convergent scheduling is able to obtain an average performance improvement of 21% over the existing space-time scheduler of the Raw processor, and an improvement of 14% over state-of-the-art assignment and scheduling techniques on a clustered VLIW architecture.
Modeling for environmental policy in India
Authors: A. Rana, T. Masui
Venue: Development and application of computer techniques to environmental studies (2002)

Environmental pollution in India, as in the rest of the world, is increasingly becoming an important issue. Despite the regulations in place the enforcement has been weak. Government policies, in addition to regulatory mechanisms, incorporate a few market based economic instruments in economic and environmental planning. However, there is little integration in the present set of economic and environmental policies in India. A need to assess integrated policies is strongly felt. In this paper, we employ a Computable General Equilibrium (CGE) model. This CGE model includes material flows along with integration of economic sectors with pollutant management activities, particularly solid waste management. Scenarios with environmental constraints and with enhanced environmental investments are constructed and compared with the reference scenario, which does not have any environmental constraints. Preliminary results indicate that the economic growth is affected when constraints, such as limit on emissions or final waste disposal, are imposed but with enhanced environmental investment these losses are mitigated.
An abstract intermediate representation in compilation systems
Authors: Dai Guilan, Tian Jinlan, Zhang Suqing, Jiang Weidu
Venue: ACM SIGPLAN Notices (2003)

The design of an intermediate representation is critical to the portability of a compiler and the efficiency of code generation. In order to increase the reusability of compiler components, and to simplify the development process of compilers, the paper presents an abstract intermediate representation (AIR) that provides a concise notation for describing the abstract syntax of programming languages and the inner data structures of compilers. AIR integrates algebraic data types into the object-oriented paradigm and thus makes it have stronger expressive power, flexibility, and extensibility. AIR separates the abstract descriptions from the concrete implementation. This makes it easier to be implemented in different high-level languages and thus improves the interoperatibility of compiler components.
Using large vs. small group projects in capstone and software engineering courses
Authors: Michael V. Stein
Venue: Journal of Computing Sciences in Colleges (2002)

Teamwork is viewed as an increasingly important facet of an education in Computer Science and related fields. One common way to include teamwork in the undergraduate curriculum is to include team projects in various course offerings. I have taught both large-group and small-group projects in upper-division undergraduate courses within the recent past. This paper compares these experiences from my viewpoint as an instructor, and identifies the factors that I have found most indicative of quality projects in both types of courses.
Instruction fetch deferral using static slack
Authors: Gregory A. Muthler, David Crowe, Sanjay J. Patel, Steven S. Lumetta
Venue: Proceedings of the 35th annual ACM/IEEE international symposium on Microarchitecture (2002)

In this paper we present an approach to boosting performance and tolerating latency by deferring non-critical instructions into a deferred queue for later processing. As such, instruction deferral allows more critical instructions to be fetched, dispatched, and possibly executed, earlier.We present methods for identifying deferrable instructions using previously investigated notions of instruction slack. In particular we use static slack to determine if an instruction is deferrable. The static slack of an instruction corresponds to the number of cycles an instruction can be delayed without impacting overall execution time when considering all dynamic paths from that instruction. A significant fraction of the dynamic instruction stream has enough static slack to be deferred by 10 or more cycles on an aggressive execution model. Futhermore, the small amount of register-based communication from deferred instructions to non-deferred instructions makes a deferral-based approach to fetch and execution very attractive.We use a trace cache based microarchitecture to overcome some significant implementation challenges associated with instruction deferral. Overall, instruction deferral boosts the performance of a 4-wide processor by approximately 11% and an 8-wide processor by 6% on eight of the SPEC2000 integer benchmarks.
Relevance of computer hardware topics in computer science curriculum
Authors: S. Krishnaprasad
Venue: Journal of Computing Sciences in Colleges (2002)

A multitude of computer hardware concepts and techniques have evolved and matured over the past few decades. Computer science students often are exposed to the breadth and depth of software topics through a variety of software and programming courses. This usually is not the case when it comes to hardware topics. We strongly feel that a balanced treatment of hardware and software concepts will better prepare our students to the sophisticated workplace. In this paper we discuss the importance and relevance of the various computer hardware topics in the computer science curriculum. We also present approaches to incorporate these topics in the curriculum for preparing a well-rounded computer science graduate.
A comparison between python and Tcl solution on four programs assigned in CS0
Authors: Peter C. Isaacson, Terry A. Scott
Venue: Journal of Computing Sciences in Colleges (2002)

This paper takes four programs that were assigned to students in a bread-first computer science course and compares the solutions when written in Tcl/Tk and Python. It then concludes with a discussion of which programming language is better in a CSO course.
Method of Hybrid Approximations for Modelling of Multidimensional Nonlinear Systems
Authors: Anatoli Torokhti, Phil Howlett, Charles Pearce
Venue: Multidimensional Systems and Signal Processing (2003)

In this paper we propose a new approach to the constructive mathematical representation of nonlinear systems transforming stochastic signals. The approach is based on a combination of a new best approximation technique and a new iterative procedure. For each iteration, the approximation is constructed as a polynomial operator of degree r which minimizes the mean&ndash;squared error between a desired output signal and the output signal of the approximating system. We show that this hybrid technique produces a computationally efficient and flexible method for modelling of nonlinear systems. The method has two degrees of freedom, the degree r of the approximating operator and the number of iterations, to decrease the associated error.
Editorial: trends in aggregation and security assessment for inference control in statistical databases
Authors: Vicenç Torra, Josep Domingo-Ferrer
Venue: International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems (2002)

As e-commerce and Internet-based data handling become pervasive, companies and statistical agencies have the need to exploit the data they accumulate without violating citizens' privacy. Inference control is a discipline whose goal is to prevent published/exchanged data from being linked with the individual respondents they originated from. This special issue illustrates that inference control largely draws on soft computing and artificial intelligence techniques.