Computer Science Technical Reports
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How Much Do Unstated Problem Constraints Limit Deep Robotic Reinforcement Learning?
(2019)Deep Reinforcement Learning is a promising paradigm for robotic control which has been shown to be capable of learning policies for high-dimensional, continuous control of unmodeled systems. However, Robotic Reinforcement Learning currently lacks clearly defined benchmark tasks, which makes it difficult for researchers to reproduce and compare against ... -
A Characterization of Compound Documents on the Web
(1999-11-29)Recent developments in office productivity suites make it easier for users to publish rich {\em compound documents\/} on the Web. Compound documents appear as a single unit of information but may contain data generated by different applications, such as text, images, and spreadsheets. Given the popularity enjoyed by these office suites and the ... -
Cache Management in Scalable Network Servers
(2000-07-13)For many users, the perceived speed of computing is increasingly dependent on the performance of network server systems, underscoring the need for high performance servers. Cost-effective scalable network servers can be built on clusters of commodity components (PCs and LANs) instead of using expensive multiprocessor systems. However, network servers ... -
Runtime Support for Distributed Sharing in Strongly-Typed Languages
(1999-11-13)In this paper, we present a new run-time system for strongly-typed programming languages that supports object sharing in a distributed system. The key insight in this system is that type information allows efficient and transparent sharing of data with both fine-grained and coarse-grained access patterns. In contrast, conventional distributed shared ... -
New Approaches to Routing for Large-Scale Data Networks
(1999-06-21)This thesis develops new routing methods for large-scale, packet-switched data networks such as the Internet. The methods developed increase network performance by considering routing approaches that take advantage of more available network resources than do current methods. Two approaches are explored: dynamic metric and multipath routing. Dynamic ... -
Programming Languages for Reusable Software Components
(1999-07-20)Programming languages offer a variety of constructs to support code reuse. For example, functional languages provide function constructs for encapsulating expressions to be used in multiple contexts. Similarly, object-oriented languages provide class (or class-like) constructs for encapsulating sets of definitions that are easily adapted for new ... -
Transformations and Transitions from the Sylvester to the Bezout Resultant
(1999-06-17)A simple matrix transformation linking the resultant matrices of Sylvester and Bezout is derived. This transformation matrix is then applied to generate an explicit formula for each entry of the Bezout resultant, and this entry formula is used, in turn, to construct an efficient recursive algorithm for computing all the entries of the Bezout matrix. ... -
A Set of Convolution Identities Relating the Blocks of Two Dixon Resultant Matrices
(1999-06-16)Resultants for bivariate polynomials are often represented by the determinants of very big matrices. Properly grouping the entries of these matrices into blocks is a very effective tool for studying the properties of these resultants. Here we derive a set of convolution identities relating the blocks of two Dixon bivariate resultant representations. -
The Block Structure of Three Dixon Resultants and Their Accompanying Transformation Matrices
(1999-06-16)Dixon [1908] introduces three distinct determinant formulations for the resultant of three bivariate polynomials of bidegree (m,n) . The first technique applies Sylvester's dialytic method to construct the resultant as the determinant of a matrix of order 6mn . The second approach uses Cayley's determinant device to form a more compact representation ... -
TCP Implementation Enhancements for Improving Webserver Performance
(1999-07-06)This paper studies the performance of BSD-based TCP implementations in Web servers. We find that lack of scalability with respect to high TCP connection rates reduces the throughput of Web servers by up to 25% and imposes a memory overhead of up to 32 MB on the kernel. We also find that insufficient accuracy in TCP's timers results in overly conservative ... -
Improving Memory Hierarchy Performance for Irregular Applications
(1999-03-10)The gap between CPU speed and memory speed in modern computer systems is widening as new generations of hardware are introduced. Loop blocking and prefetching transformations help bridge this gap for regular applications; however, these techniques don't deal well with irregular applications. This paper investigates using data and computation reordering ... -
A Deterministic Model for Parallel Program Performance Evaluation
(1998-12-03)Analytical models for parallel programs have been successful at providing simple qualitative insights and bounds on scalability, but have been less successful in practice for predicting detailed, quantitative information about program performance. We develop a conceptually simple model that provides detailed performance prediction for parallel programs ... -
Operating system support for server applications
(1999-05-25)General-purpose operating systems provide inadequate support for large-scale servers. Server applications lack sufficient control over scheduling and management of machine resources, which makes it difficult to enforce priority policies, and to provide robust and controlled service. For example, server applications cannot provide differentiated quality ... -
Bisimulation Minimization in an Automata-Theoretic Verification Framework
(1998-10-27)Bisimulation is a seemingly attractive state-space minimization technique because it can be computed automatically and yields the smallest model preserving all mu -calculus formulas. It is considered impractical for symbolic model checking, however, because the required BDDs are prohibitively large for most designs. We revisit bisimulation minimization, ... -
An Experimental Evaluation of List Scheduling
(1998-09-30)While altering the scope of instruction scheduling has a rich heritage in compiler literature, instruction scheduling algorithms have received little coverage in recent times. The widely held belief is that greedy heuristic techniques such as list scheduling are "good" enough for most practical purposes. The evidence supporting this belief is largely ... -
Mathematical Properties of Variational Subdivision Schemes
(1998-09-24)Subdivision schemes for variational splines were introduced in a previous paper. This technical report focuses on discussing the mathematical properties of these subdivision schemes in more detail. Please read the original paper before reading this analysis. -
Issues in Instruction Scheduling
(1998-09-15)Instruction scheduling is a code reordering transformation that attempts to hide latencies present in modern day microprocessors. Current applications of these microprocessors and the microprocessors themselves present new parameters under which the scheduler must operate. For example, some multiple functional unit processors have partitioned register ... -
A Linear Transform Scheme for Combining Weights into Scores
(1998-10-09)Ranking has been widely used in many applications. A ranking scheme usually employs a "scoring rule" that assigns a final numerical value to each and every object to be ranked. A scoring rule normally involves the use of one or many scores, and it gives more weight to the scores that is more important. In this paper, we give a scheme that can combine ... -
A New Approach to Routing With Dynamic Metrics
(1998-11-18)We present a new routing algorithm to compute paths within a network using dynamic link metrics. Dynamic link metrics are cost metrics that depend on a link's dynamic characteristics, e.g., the congestion on the link. Our algorithm is destination-initiated: the destination initiates a global path computation to itself using dynamic link metrics. All ... -
A Simple, Practical Distributed Multi-Path Routing Algorithm
(1998-07-16)We present a simple and practical distributed routing algorithm based on backward learning. The algorithm periodically floods \emscout packets that explore paths to a destination in reverse. Scout packets are small and of fixed size; therefore, they lend themselves to hop-by-hop piggy-backing on data packets, largely defraying their cost to the ...
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