ppxscal/embedding_network huggingface dataset:
On Spectrum and Riesz Basis Assignment of Infinite-Dimensional Linear Systems By Bounded Linear Feedbacks
Authors: Cheng-Zhong Xu, Gauthier Sallet
Venue: SIAM Journal on Control and Optimization (1996)

This paper deals with spectrum and Riesz basis assignability of infinite-dimensional linear systems via bounded linear feedbacks. The necessary and sufficient condition of Sun [SIAM J. Control Optim., 19 (1981), pp. 730--743] is generalized to a large class of boundary control systems. Two typical examples are presented to illustrate the application of our results. The results obtained in this paper may have potential applications in nondissipative spectral systems.
The HP AutoRAID hierarchical storage system
Authors: John Wilkes, Richard Golding, Carl Staelin, Tim Sullivan
Venue: ACM Transactions on Computer Systems (TOCS) (1996)

Configuring redundant disk arrays is a black art. To configure an array properly, a system administrator must understand the details of both the array and the workload it will support. Incorrect understanding of either, or changes in the workload over time, can lead to poor performance. We present a solution to this problem: a two-level storage hierarchy implemented inside a single disk-array controller. In the upper level of this hierarchy, two copies of active data are stored to provide full redundancy and excellent performance. In the lower level, RAID 5 parity protection is used to provide excellent storage cost for inactive data, at somewhat lower performance. The technology we describe in this article, know as HP AutoRAID, automatically and transparently manages migration of data blocks between these two levels as access patterns change. The result is a fully redundant storage system that is extremely easy to use, is suitable for a wide variety of workloads, is largely insensitive to dynamic workload changes, and performs much better than disk arrays with comparable numbers of spindles and much larger amounts of front-end RAM cache. Because the implementation of the HP AutoRAID technology is almost entirely in software, the additional hardware cost for these benefits is very small. We describe the HP AutoRAID technology in detail, provide performance data for an embodiment of it in a storage array, and summarize the results of simulation studies used to choose algorithms implemented in the array.
A dual bus approach for LAN interworking with ATM networks
Authors: Chiung-Shien Wu, Nen-Fu Huang, Gin-Kou Ma
Venue: ACM SIGCOMM Computer Communication Review (1995)

The interworking between conventional legacy LANs and the ATM network plays an important role in the initial step of the ATM roadmap. This paper presents a dual bus approach for connecting LAN interworking units (IWU) to ATM networks. Several IWUs connecting heterogeneous LANs are configured into a dual bus structure and the end of the buses are directly connected to the ATM ports. Each IWU transforms the connectionless frame from the legacy LAN to fixed-length time-slots on the dual bus. To provide reliable connectionless services, a cell-based flow control scheme is proposed for dynamically adjusting the cell input rate so as to match with the current resources in the ATM switch. The scheme is further verified to be able to provide an optimal, best-effort and reliable interconnection scenario through simulations. The results show that the total throughput obtained by each local subnetwork dynamically matches with the cell processing throughput of the ATM switch. Besides, each IWU on the dual bus shares a fair bandwidth.
Performance analysis of DS-CDMA with slotted ALOHA random access for packet PCNs
Authors: Zhao Liu, Magda El Zarki
Venue: Wireless Networks (1995)

In this paper, we present a discrete time Markov chain based analytical framework for the study of Direct-Sequence Code-Division-Multiple-Access (DS-CDMA) with slotted ALOHA random access protocols (DS-CDMA-S-ALOHA) for packet Personal Communications Networks (PCNs). It incorporates both the random access and the random errors associated with DS-CDMA-S-ALOHA protocols into a unified framework. The key feature is that it distinguishes between the two stages in the transmission process, namely the access stage and the reception stage, which characterize the random access and the random errors associated with DS-CDMA-S-ALOHA protocols respectively. Two DS-CDMA-S-ALOHA protocols are presented and analyzed. The performance of the protocols and the effects of the design parameters, namely the packet retransmission probability and the forward error correction code rate of the Bose-Chaudhuri-Hocquenghem (BCH) block codes are evaluad numerically and compared with a bandwidth equivalent conventional multi-channel slotted ALOHA system. The results show that, by proper design, the DS-CDMA-S-ALOHA protocols can double the throughput with respect to that of a bandwidth equivalent conventional multi-channel slotted ALOHA system.
Equilibrium states of Runge Kutta schemes
Authors: George Hall
Venue: ACM Transactions on Mathematical Software (TOMS) (1985)

Understanding the behavior of Runge-Kutta codes when stability considerations restrict the stepsize provides useful information for stiffness detection and other implementation details. Analysis of equilibrium states on test problems is presented which provides predictions and insights into this behavior. The implications for global error are also discussed.
Spontaneous excitations in the visual cortex: stripes, spirals, rings, and collective bursts
Authors: Corinna Fohlmeister, Wulfram Gerstner, Raphael Ritz, J. Leo van Hemmen
Venue: Neural Computation (1995)

As a simple model of the cortical sheet, we study a locally connected net of spiking neurons, Refractoriness, noise, axonal delays, and the time course of excitatory and inhibitory postsynaptic potentials are taken into account explicitly. In addition to a low-activity state and depending on the synaptic efficacy, four different scenarios evolve spontaneously, viz., stripes, spirals, rings, and collective bursts. Our results can be related to experimental observations of drug-induced epilepsy and hallucinations.
The ultimate bead counter: efficient massively parallel simulation of ballistic deposition
Authors: Boris D. Lubachevsky, Vladimir Privman, Subhas C. Roy
Venue: ACM SIGSIM Simulation Digest (1995)

We simulate ballistic particle deposition wherein a large number of spherical particles are &ldquo;dropped&rdquo; vertically over a planar horizontal surface. Upon first contact (with the surface or with a previously deposited particle) each particle stops. This model helps material scientists to study the adsorption and sediment formation [1]. The model is sequential, with particles deposited one by one. We have found an equivalent formulation using a continuous time random process and we simulate the latter in parallel using a method similar to the one previously employed for simulating Ising spins [2]. We augment the parallel algorithm for simulating Ising spins with several techniques aimed at the increase of efficiency of producing the particle configuration and statistics collection. Some of these techniques are similar to [3], [4], [5]. We implement the resulting algorithm on a 16K PE MasPar MP-1 and a 4K PE MasPar MP-2. The parallel code runs on MasPar computers two orders of magnitude faster than an optimized sequential code runs on a fast workstation.
Using naming strategies to make massively parallel systems work
Authors: Henning Schmidt
Venue: Scientific Programming (1994)

To handle massively parallel systems and make them usable, an adaptive, application-oriented operating system is required. The application orientedness is represented by the family concept of parallel operating systems. Incremental loading of operating system services supports the family character by automatically extending the system's active object structure when it is necessary. This way, also the switching between different operating system family members may be realized. A new active object will be incrementally loaded if its invocation fails because it does not yet exist. This is noticed during object binding while using the naming services. The use of the naming system is exploited and extended to get a flexible and configurable mechanism for triggering incremental loading. This mechanism is built by the freely definable naming strategies and exceptions that result again in a family, namely a family of naming services.
Is APL2 a good programming language?
Authors: Nicholas Beaumont
Venue: ACM SIGAPL APL Quote Quad (1995)

This paper evaluates APL2 in the context of systems development, noting that a language is not an end in itself, but one of several tools used to create an information system. Despite its many good features APL2, when evaluated in that context, has some disadvantages, especially the lack of control structures and data typing. These omissions make finding errors in programs and translating system requirements into programs harder than necessary. These and other disadvantages of APL2 (such as its lack of portability) make its relative unpopularity explicable. Some changes to APL2 are suggested.
Design of FPGAs with area I/O for field programmable MCM
Authors: Vijayshri Maheshwari, Joel Darnauer, John Ramirez, Wayne Wei-Ming Dai
Venue: Proceedings of the 1995 ACM third international symposium on Field-programmable gate arrays (1995)

Area-IO provide a way to eliminate the IO bottleneck of field programmable logic devices (FPLDs) created the mismatch between the ability of perimeter bonds to provide IO and the propensity of logic to demand it. Whether the incorporation of area IO into FPLD architectures has undesirable side effects is a question that has not yet been answered. In this paper, we examine the architectural impact of area-IO on FPLDs from a theoretical and experimental standpoint and show that the introduction of area IO generally improves the routability and delay of a set of benchmark circuits.
Multiway Merging in Parallel
Authors: Zhaofang Wen
Venue: IEEE Transactions on Parallel and Distributed Systems (1996)

The problem of merging k (k¿ 2) sorted lists is considered. We give an optimal parallel algorithm which takes $O({\textstyle{{n\log k} \over p}}+\log n)$ time using p processors on a parallel random access machine that allows concurrent reads and exclusive writes, where n is the total size of the input lists. This algorithm achieves O(log n) time using $p={\textstyle{{n\log k} \over {\log n}}}$ processors. Most of the previous research for this problem has been focused on the case when k = 2. Very recently, parallel solutions for the case when k > 2 have been reported. Our solution is the first logarithmic time optimal parallel algorithm for the problem when k¿ 2. It can also be seen as a unified optimal parallel algorithm for sorting and merging. In order to support the algorithm, a new processor assignment strategy is also presented.
Pricing of financial derivatives via simulation
Authors: Michael C. Fu
Venue: Proceedings of the 27th conference on Winter simulation (1995)

The word "derivative" has led a ubiquitous existence in the news in recent years. This paper gives a tutorial on financial derivatives and the use of Monte Carlo simulation techniques for their pricing. We provide the basic financial terminology and key concepts in the field, focusing on options pricing, in particular. Although no prior knowledge of finance is assumed in the exposition, previous experience with stochastic simulations-generation of random inputs and basic statistical output analysis-is requisite.
Algorithm 743: WAPR--a Fortran routine for calculating real values of the W-function
Authors: D. A. Barry, S. J. Barry, P. J. Culligan-Hensley
Venue: ACM Transactions on Mathematical Software (TOMS) (1995)

We implement W-function approximation scheme described by Barry et al. A range of tests of the approximations is included so that the code can be assessed on any given machine. Users can calculate W(x) by specifying x itself or by specifying an offset from &minus;exp(&minus;1), the latter option necessitated by rounding errors that can arise for x close to &minus;exp(&minus;1). Results of running the code on a SUN workstation are included.
Computing Exact Componentwise Bounds on Solutions of Linear Systems with Interval Data isNP-Hard
Authors: Jiri Rohn, Vladik Kreinovich
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

We prove that it is NP-hard to compute the exact componentwise bounds on solutions of all the linear systems that can be obtained from a given linear system with a nonsingular matrix by perturbing all the data independently of each other within prescribed tolerances.
On the self-similar nature of Ethernet traffic
Authors: Will E. Leland, Walter Willinger, Murad S. Taqqu, Daniel V. Wilson
Venue: ACM SIGCOMM Computer Communication Review (1995)

We demonstrate that Ethernet local area network (LAN) traffic is statistically self-similar, that none of the commonly used traffic models is able to capture this fractal behavior, and that such behavior has serious implications for the design, control, and analysis of high-speed, cell-based networks. Intuitively, the critical characteristic of this self-similar traffic is that there is no natural length of a "burst": at every time scale ranging from a few milliseconds to minutes and hours, similar-looking traffic bursts are evident; we find that aggregating streams of such traffic typically intensifies the self-similarity ("burstiness") instead of smoothing it.Our conclusions are supported by a rigorous statistical analysis of hundreds of millions of high quality Ethernet traffic measurements collected between 1989 and 1992, coupled with a discussion of the underlying mathematical and statistical properties of self-similarity and their relationship with actual network behavior. We also consider some implications for congestion control in high-bandwidth networks and present traffic models based on self-similar stochastic processes that are simple, accurate, and realistic for aggregate traffic.
DuFort--Frankel-Type Methods for Linear and Nonlinear Schrödinger Equations
Authors: Lixin Wu
Venue: SIAM Journal on Numerical Analysis (1996)

In this paper we propose a so-called DuFort--Frankel-type method for the linear and nonlinear Schrödinger equations. Schemes of the DuFort--Frankel type are explicit and have solution-independent stability criteria. Moreover, the DuFort--Frankel-type method satisfies a discrete conservation law for the Schrödinger equations, and this is important to get reliable numerical solutions.
High performance messaging on workstations: Illinois fast messages (FM) for Myrinet
Authors: Scott Pakin, Mario Lauria, Andrew Chien
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

The Convex SPP-1000 is the first commercial implementation of a new generation of scalable shared memory parallel computers with full cache coherence. It employs a hierarchical structure of processing communication and memory name-space management resources to provide a scalableNUMA environment. Ensembles of 8 HP PA-RISC7100 microprocessorsemploy an internal cross-bar switch and directory based cache coherence scheme to provide a tightly coupled SMP.Up to 16 processing ensembles are interconnected by a 4 ring network incorporating a full hardware implementation of the SCI protocol for a full system configuration of 128 processors. This paper presents the findings of a set of empirical studies using both synthetic test codes and full applications for the Earth and space sciences to characterize the performance properties of this new architecture. It is shown that overhead and latencies of global primitive mechanisms, while low in absolute time, are significantly more costly than similar functions local to an individual processor ensemble.
Tolerating Sensor Timing Faults in Highly Responsive Hard Real-Time Systems
Authors: Stefan Poledna
Venue: IEEE Transactions on Computers (1995)

Real-time systems that have to respond to environmental state changes within a very short latency period often use event-triggered task activation. If the system has to function correctly in the presence of sensor faults, event-triggered task activation is not reliable. Faulty sensors may cause task activations to occur too early, too late, or task activations are omitted entirely. In particular, early task activations can overload the system. Time-triggered task activation is reliable, but by defining a competitiveness ratio it is shown that the processor utilization for highly responsive tasks is unacceptably low. To overcome the problems of event-triggered task activation while preserving its good performance the task-splitting model is introduced. The task-splitting model integrates fault tolerance into the analysis and construction of hard real-time systems by using a combination of event-triggered and time-triggered task activation. Based on a general task model, it is independent of any particular scheduling algorithm. The result of this work has influenced the design of a new operating system which will be applied in a robust automotive engine controller of the next generation.Index Terms¿Sensor timing faults, fault tolerance, hard real-time systems, event-triggered task activation, competitiveness of task activation.
The repair of speech act misunderstandings by abductive inference
Authors: Susan W. McRoy, Graeme Hirst
Venue: Computational Linguistics (1995)

During a conversation, agents can easily come to have different beliefs about the meaning or discourse role of some utterance. Participants normally rely on their expectations to determine whether the conversation is proceeding smoothly: if nothing unusual is detected, then understanding is presumed to occur. Conversely, when an agent says something that is inconsistent with another's expectations, then the other agent may change her interpretation of an earlier turn and direct her response to the reinterpretation, accomplishing what is known as a fourth-turn repair.Here we describe an abductive account of the interpretation of speech acts and the repair of speech act misunderstandings. Our discussion considers the kinds of information that participants use to interpret an utterance, even if it is inconsistent with their beliefs. It also considers the information used to design repairs. We describe a mapping between the utterance-level forms (semantics) and discourse-level acts (pragmatics), and a relation between the discourse acts and the beliefs and intentions that they express. We specify for each discourse act, the acts that might be expected, if the hearer has understood the speaker correctly. We also describe our account of belief and intention, distinguishing the beliefs agents actually have from the ones they act as if they have when they perform a discourse act. To support repair, we model how misunderstandings can lead to unexpected actions and utterances and describe the processes of interpretation and repair. To illustrate the approach, we show how it accounts for an example repair.
Integrating Multiple Paradigms within the Blackboard Framework
Authors: Sanja Vraneš, Mladen Stanojevic
Venue: IEEE Transactions on Software Engineering (1995)

While early knowledge-based systems suffered the frequent criticism of having little relevance to the real world, an increasing number of current applications deal with complex, real-world problems. Due to the complexity of real-world situations, no one general software technique can produce adequate results in different problem domains, and artificial intelligence usually needs to be integrated with conventional paradigms for efficient solutions. The complexity and diversity of real-world applications have also forced the researchers in the AI field to focus more on the integration of diverse knowledge representation and reasoning techniques for solving challenging, real-world problems. Our development environment, BEST (Blackboard-based Expert Systems Toolkit), is aimed to provide the ability to produce large-scale, evolvable, heterogeneous intelligent systems. BEST incorporates the best of multiple programming paradigms in order to avoid restricting users to a single way of expressing either knowledge or data. It combines rule-based programming, object-oriented programming, logic programming, procedural programming and blackboard modelling in a single architecture for knowledge engineering, so that the user can tailor a style of programming to his application, using any or arbitrary combinations of methods to provide a complete solution. The deep integration of all these techniques yields a toolkit more effective even for a specific single application than any technique in isolation or collections of multiple techniques less fully integrated. Within the basic, knowledge-based programming paradigm, BEST offers a multiparadigm language for representing complex knowledge, including incomplete and uncertain knowledge. Its problem solving facilities include truth maintenance, inheritance over arbitrary relations, temporal and hypothetical reasoning, opportunistic control, automatic partitioning and scheduling, and both blackboard and distributed problem-solving paradigms.
What is a &ldquo;pointer machine&rdquo;?
Authors: Amir M. Ben-Amram
Venue: ACM SIGACT News (1995)

A "Pointer Machine" is many things. Authors who consider referring to this term are invited to read the following note first.
Towards effective and efficient free space management
Authors: Mark L. McAuliffe, Michael J. Carey, Marvin H. Solomon
Venue: ACM SIGMOD Record (1996)

An important problem faced by many database management systems is the "online object placement problem"--the problem of choosing a disk page to hold a newly allocated object. In the absence of clustering criteria, the goal is to maximize storage utilization. For main-memory based systems, simple heuristics exist that provide reasonable space utilization in the worst case and excellent utilization in typical cases. However, the storage management problem for databases includes significant additional challenges, such as minimizing I/O traffic, coping with crash recovery, and gracefully integrating space management with locking and logging.We survey several object placement algorithms, including techniques that can be found in commercial and research database systems. We then present a new object placement algorithm that we have designed for use in Shore, an object-oriented database system under development at the University of Wisconsin--Madison. Finally, we present results from a series of experiments involving actual Shore implementations of some of these algorithms. Our results show that while current object placement algorithms have serious performance deficiencies, including excessive CPU or main memory overhead, I/O traffic, or poor disk utilization, our new algorithm consistently excellent performance in all of these areas.
An automatic procedure for topic-focus identification
Authors: Eva Hajičová, Petr Sgall, Hana Skoumalová
Venue: Computational Linguistics (1995)

The dichotomy of topic and focus, based, in the Praguean Functional Generative Description, on the scale of communicative dynamism, is relevant not only for a possible placement of the sentence in a context, but also for its semantic interpretation. An automatic identification of topic and focus may use the input information on word order, on the systemic ordering of kinds of complementations (reflected by the underlying order of the items included in the focus), on definiteness, and on lexical semantic properties of words. An algorithm for the analysis of English sentences has been implemented and is discussed and illustrated on several examples.