ppxscal/embedding_network huggingface dataset:
A Method for the Specification and Parsing of Visual Languages
Authors: Eric J. Golin
Venue:  (1991)

Visual programming languages use pictures formed from graphical elements as programs rather than strings of text. A visual program is a diagram specifying a computation. Examples of visual programming languages include many types of diagrams traditionally used within computer science, such as data flow diagrams, finite-state diagrams and flowcharts, as well as graphical methodologies developed for software engineering and new languages such as StateCharts developed to exploit the visual paradigm. One problem that has hampered research in visual programming languages is the lack of a syntax-definition mechanism. The specification of syntax and parsing of programs is well understood for textual programming languages. Both formal methods for syntax specification (e.g. context-free grammars) and practical tools (such as yacc) have proven valuable to language developers. Visual language syntax is more complicated because of the two-dimensional nature of the languages. Previous visual programming environments largely used {\em ad hoc} specifications and special-purpose structure editors to handle visual language syntax. The {\em attributed multiset grammar} is a formal model for generating languages that are collections of objects. {\em Picture layout grammars} are a specification mechanism for visual language syntax based on attributed multiset grammars. Using picture layout grammars, a language designer can define both the syntactic structure and the two-dimensional layout of a visual language. A {\em spatial parser} is an algorithm to recover the syntactic structure of a visual program from an unstructured picture representation. This dissertation develops the attributed multiset grammar model and gives a spatial parsing algorithm for picture layout grammars. It also describes the GREEN environment, which combines an object-oriented graphics editor with the spatial parser to form a grammar-based visual programming environment.
NUMA Multiprocessor Page Placement Policies
Authors: P R LaRowe, S C Ellis
Venue:  (1989)

In many parallel applications, the size of the program''s data exceeds even the very large amount of main memory available on large-scale multiprocessors. Virtual memory, in the sense of a transparent management of the main/secondary memory hierarchy, is a natural solution. The replacement, fetch, and placement policies used in uniprocessor paging systems need to be reexamined in light of the differences in the behavior of parallel computations and in the memory architectures of multiprocessors. In particular, we investigate the impact of page placement in non-uniform memory access time (NUMA) shared memory MIMD machines. We experimentally evaluate several paging algorithms that incorporate different approaches to the placement issue. Under certain workload assumptions, our results show that placement algorithms that are strongly biased toward local frame allocation but are able to borrow remote frames can reduce the number of faults and improve the overall computation execution time over strictly local allocation. The increased cost of memory operations due to the extra remote accesses is more than compensated for by the savings resulting from the reduction in demand fetches. We also discuss some early results obtained from an actual kernel implementation of one of our page placement algorithms.
Constructing Symbols as Manipulable Structures by Recurrent Networks
Authors: J. G. Taylor, N. R. Taylor, B Apolloni, C Orovas
Venue: Proceedings of the IEEE-INNS-ENNS International Joint Conference on Neural Networks (IJCNN'00)-Volume 2 - Volume 2 (2000)

A simple approach is developed to use semantics as defined by virtual actions to guide the construction of manipulable symbol representations for objects and actions, in particular to obtain a model of syntactic processing in the developing infant. This uses a simplified model of the frontal lobes, and in particular, the various sets of neurons involved in the process of chunking of temporal sequences observed in monkeys. The manner in which such neurons play a role in phrase structure grammar is elucidated at a simple level.
Design of a Distributed Fault-Tolerant Computer Architecture Applied to the Traffic Control System "IVMS"
Authors: Erwin Duschnig
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

This paper presents the design of a fault-tolerant computer architecture for the traffic control system IVMS (Intelligent Variable Message Sign). In this project, IVMS stations with point-to-point communication links are to be installed along highways so as to control the traffic flow, yielding homogeneity. The principal design goal is to achieve high system availability at low cost; the availability is calculated by Markov models. Comparing several candidate architectures, we have found that a distributed IVMS system based on simplex computers without static redundancy, is the most interesting architecture, because it allows degradation. We discuss fault tolerance measures for transient failures, which occur much more frequently than permanent failures, and propose solutions for the stable storage concept and for network partitioning.
Mooshak: a Web-based multi-site programming contest system
Authors: José Paulo Leal, Fernando Silva
Venue: Software&mdash;Practice Experience (2003)

This paper presents a new Web-based system, Mooshak, to handle programming contests. The system acts as a full contest manager as well as an automatic judge for programming contests. Mooshak innovates in a number of aspects: it has a scalable architecture that can be used from small single server contests to complex multi-site contests with simultaneous public online contests and redundancy; it has a robust data management system favoring simple procedures for storing, replicating, backing up data and failure recovery using persistent objects; it has automatic judging capabilities to assist human judges in the evaluation of programs; it has built-in safety measures to prevent users from interfering with the normal progress of contests. Mooshak is an open system implemented on the Linux operating system using the Apache HTTP server and the Tcl scripting language.This paper starts by describing the main features of the system and its architecture with reference to the automated judging, data management based on the replication of persistent objects over a network. Finally, we describe our experience using this system for managing two official programming contests.
Coverage testing software architectural design in SDL
Authors: W. Eric Wong, Tatiana Sugeta, J. Jenny Li, José C. Maldonado
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2003)

Statistical data analysis shows that early fault detection can cut cost significantly. With improved technology for automatic code generation from architectural design specifications, it becomes even more important to have, from the beginning, a highly reliable and dependable architectural design. To ensure this, we have to predict the "quality" of the system early in the development process. The use of traces or execution histories as an aid to testing and analysis is well established for programming languages like C and C++, but it is rarely applied in the field of software specification for designs. We propose a solution by applying our technology at source code level to coverage testing software designs represented in a high-level specification and description language such as SDL. Sophisticated dominator analysis is applied to provide hints on how to generate efficient test cases to increase, as much as possible with as few tests as possible, the control-flow- and data-flow-based coverage of the SDL specification being tested. We extend source code-based coverage testing to the software design specification level for specification validation. A coverage analysis tool, CATSDL, with user-friendly interfaces was developed to support our method. An illustration is provided to demonstrate the feasibility of using our method to validate the architectural design efficiently in terms of higher testing coverage and lower cost.
Providing bandwidth guarantees in an input-buffered crossbar switch
Authors: D. Stiliadis, A. Varma
Venue: Proceedings of the Fourteenth Annual Joint Conference of the IEEE Computer and Communication Societies (Vol. 3)-Volume - Volume 3 (1995)

Introduces and analyzes a method for providing bandwidth reservations in an input-buffered non-blocking crossbar switch. The scheme, which the authors call weighted probabilistic iterative matching (WPIM), is an improvement over probabilistic iterative matching and allows flexible allocation of bandwidth among the switch inputs sharing a common output link in a simple manner. Weighted probabilistic iterative matching allocates the output bandwidth among the inputs based on reservations made during the connection setup phase, and can guarantee that traffic from each input receives its promised share of the bandwidth of the output link. In addition, the algorithm provides isolation between two flows arriving on distinct input links and directed at a common output link; misbehaving flows at one of the inputs do not affect the bandwidth guarantees or delays of traffic from other inputs. Results from simulations show that the scheme is able to maintain probabilistic bandwidth and delay guarantees in the presence of misbehaving traffic. the authors also derive an analytical upper bound for the average delay under the scheme and validate it by simulation.
Essential and Incidental Complexity in Requirements Models
Authors: L. Nguyen, P. A. Swatman
Venue: Proceedings of the 4th International Conference on Requirements Engineering (ICRE'00) (2000)

A deep understanding of the complexity of the requirements model and its dynamics is critical in improving requirements engineering process management. Findings from an action research study reported in this paper offer an insightful explanation of how the complexity of the requirements model evolves over time. We argue that there are two different types of complexity of the model .the essential and incidental complexities. The essential complexity represents the inherent understanding of the problem space while the incidental complexity arises from the poor fit between the structure of the model and the structure of the world, which the model aims to represent. We present a pattern for the dynamics of changes in the complexity of the requirements model. The evolution of the requirements model involves both the growth of the essential complexity throughout the discovery of the problem space and the growth and shrinkage of the incidental complexity as the model undergoes a large number of changes. The new understanding of the complexity of the requirements model and its dynamics draws new directions for future research and forms a basis for a new approach to process management.
SNMP at the Edge, 1 edition
Authors: Jonathan Saperia
Venue:  (2002)

:To manage a service network,managers have to control the network,the application,and the receiving devicesand that's not an easy assignment. Here is a hands-on manual detailing how to design and deploy effective service management systems. * Covers everything service managers need to know: designing systems,purchasing program software,automating applications,configuring edge devices,testing,monitoring and measuring * Anlayzes why our current network software and standards have so far been failures * Walks readers through the steps of building a complete SNMP (Simple Network Management Protocol) edge management system * Dissects and compares the many competing management protocols now in play The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Managing and Sharing Servents' Reputations in P2P Systems
Authors: Ernesto Damiani, Sabrina De Capitani di Vimercati, Stefano Paraboschi Pierangela Samarati
Venue: IEEE Transactions on Knowledge and Data Engineering (2003)

Peer-to-peer information sharing environments are increasingly gaining acceptance on the Internet as they provide an infrastructure in which the desired information can be located and downloaded while preserving the anonymity of both requestors and providers. As recent experience with P2P environments such as Gnutella shows, anonymity opens the door to possible misuses and abuses by resource providers exploiting the network as a way to spread tampered-with resources, including malicious programs, such as Trojan Horses and viruses. In this paper, we propose an approach to P2P security where servents can keep track, and share with others, information about the reputation of their peers. Reputation sharing is based on a distributed polling algorithm by which resource requestors can assess the reliability of perspective providers before initiating the download. The approach complements existing P2P protocols and has a limited impact on current implementations. Furthermore, it keeps the current level of anonymity of requestors and providers, as well as that of the parties sharing their view on others' reputations.
Maximum cuts and judicious partitions in graphs without short cycles
Authors: Noga Alon, Béla Bollobás, Michael Krivelevich, Benny Sudakov
Venue: Journal of Combinatorial Theory Series B (2003)

We consider the bipartite cut and the judicious partition problems in graphs of girth at least 4. For the bipartite cut problem we show that every graph G with m edges, whose shortest cycle has length at least r≥4, has a bipartite subgraph with at least /m2; + c(r)mr/r+1 edges. The order of the error term in this result is shown to be optimal for r = 5 thus settling a special case of a conjecture of Erdös. (The result and its optimality for another special case, r = 4, were already known.) For judicious partitions, we prove a general result as follows: if a graph G = (V, E) with m edges has a bipartite cut of size /m2; + δ, then there exists a partition V = V1 ∪ V2 such that both parts V1, V2 span at most /m4; - (1 - o(1))/δ2; + O(√m) edges for the case δ = o(m), and at most (1/4-Ω(1))m edges for δ = Ω(m). This enables one to extend results for the bipartite cut problem to the corresponding ones for judicious partitioning.
Flexible Autonomous Decentralized Technology for Heterogeneous Requirements from Reusable Launch Vehicle
Authors: Toshiki Morito, Masahiro Ohno, Masao Wakamiya, Kinji Mori
Venue: Proceedings of the The Sixth International Symposium on Autonomous Decentralized Systems (ISADS'03) (2003)

In many space development programs, Reusable Launch Vehicle (RLV) concepts are focused on, to improve the reliability and to reduce the operational cost.The avionic systems of RLV must meet the fault tolerance and real-time requirements.These requirements must be satisfied simultaneously in the various situations. Moreover, the system configurations may be changed because of the mission or the maintenance. Therefore, the flexibility is also required.These heterogeneous requirements are difficult to be satisfied with conventional technologies, which usually apply specified hardware or software components. Hence, the new system technology, the "Flexible Autonomous Decentralized Technology for Heterogeneous Requirements (FATHER)" is proposed. The FATHER satisfies the heterogeneous requirements with a single simple and common software structure, which is based on the data field architecture.The FATHER is effective not only for RLV, but also for other systems, such as traffic systems and huge plant systems with the heterogeneous requirements.
Understanding Change-Proneness in OO Software through Visualization
Authors: James M. Bieman, Anneliese A. Andrews, Helen J. Yang
Venue: Proceedings of the 11th IEEE International Workshop on Program Comprehension (2003)

During software evolution, adaptive, and corrective maintenance are common reasons for changes. Often such changes cluster around key components. It is therefore important to analyze the frequency of changes to individual classes, but, more importantly, to also identify and show related changes in multiple classes. Frequent changes in clusters of classes may be due to their importance, due to the underlying architecture or due to chronic problems. Knowing where those change-prone clusters are can help focus attention, identify targets for re-engineering and thus provide product-based information to steer maintenance processes. This paper describes a method to identify and visualize classes and class interactions that are the most change-prone. The method was applied to a commercial embedded, real-time software system. It is object-oriented software that was developed using design patterns.
A Video Retrieval Protocol with Video Data Prefetch and Packet Retransmission Considering Play-out Dead Line
Authors: Teruyuki Hasegewa, Toru Hasegawa, Toshihiko Kato, Kenji Suzuki
Venue: Proceedings of the 1996 International Conference on Network Protocols (ICNP '96) (1996)

Most of current video retrieval systems use video transfer protocols such that servers simply transmit video packets in the same rate as clients play them. If any packets are corrupted during transmission, they will be lost and cannot be recovered by retransmission. In video retrieval systems, however, the video data are stored in servers and clients can prefetch them prior to playing. So, it might be possible for the video retrieval systems to make corrupted video packets retransmitted before play-out dead line. But the application of existing reliable protocols causes problems such that, if a packet does not arrives before the dead line due to retransmission, the packets following it will not be delivered to the upper layer even if they have already arrived. In this paper, we proposed a new video transfer protocol for video retrieval systems over ATM network, which provides the video data prefetch, the flow control for video buffer, the selective retransmission with skipping function for video packets late for the play-out dead line, and the resynchronaization function for video buffer. We have implemented an experimental system using our protocol and evaluated the performance. The results of performance evaluation shows that the proposed protocol decreases the number of unplayed video data to less than 1/70 compared with the conventional non-retransmission protocol when random bit errors with BER of 1E-6 are inserted in an ATM network. Keywords : Protocol, Video, Retrieve, Prefetch, Retransmission, ATM, SSCOP
Scaling internet routers using optics
Authors: Isaac Keslassy, Shang-Tse Chuang, Kyoungsik Yu, David Miller, Mark Horowitz, Olav Solgaard, Nick McKeown
Venue: Proceedings of the 2003 conference on Applications, technologies, architectures, and protocols for computer communications (2003)

Routers built around a single-stage crossbar and a centralized scheduler do not scale, and (in practice) do not provide the throughput guarantees that network operators need to make efficient use of their expensive long-haul links. In this paper we consider how optics can be used to scale capacity and reduce power in a router. We start with the promising load-balanced switch architecture proposed by C-S. Chang. This approach eliminates the scheduler, is scalable, and guarantees 100% throughput for a broad class of traffic. But several problems need to be solved to make this architecture practical: (1) Packets can be mis-sequenced, (2) Pathological periodic traffic patterns can make throughput arbitrarily small, (3) The architecture requires a rapidly configuring switch fabric, and (4) It does not work when linecards are missing or have failed. In this paper we solve each problem in turn, and describe new architectures that include our solutions. We motivate our work by designing a 100Tb/s packet-switched router arranged as 640 linecards, each operating at 160Gb/s. We describe two different implementations based on technology available within the next three years.
Independence Results in Computer Science
Authors: Juris Hartmanis, John E. Hopcroft
Venue:  (1976)

In this note we show that instances of problems which appear naturally in computer science cannot be answered in formalized set theory. We show, for example, that some relativized versions of the famous P = NP problem cannot be answered in formalized set theory, that explicit algorithms can be given whose running time is independent of the axioms of set theory, and that one can exhibit a specific context-free grammar G for which it cannot be proven in set theory that $L(G) = \sum^{\*}$ or $L(G) \neq \sum^{\*}$.
Equational term graph rewriting
Authors: Zena M. Ariola, Jan W Klop
Venue:  (1995)

We present an equational framework for term graph rewriting with cycles. The usual notion of homomorphism is phrased in terms of the notion of bisimulation, which is well-known in process algebra and concurrency theory. Specifically, a homomorphism is a functional bisimulation. We prove that the bisimilarity class of a term graph, partially ordered by functional bisimulation, is a complete lattice. It is shown how Equational Logic induces a notion of copying and substitution on term graphs, or systems of recursion equations, and also suggests the introduction of hidden or nameless nodes in a term graph. Hidden nodes can be used only once. The general framework of term graphs with copying is compared with the more restricted copying facilities embodied in the $\mu$-rule, and translations are given between term graphs and $\mu$-expressions. Using these, a proof system is given for $\mu$-expressions that is complete for the semantics given by infinite tree unwinding. Next, orthogonal term graph rewrite systems, also in the presence of copying and hidden nodes, are shown to be confluent.
TCP performance analysis on asymmetric networks composed of satellite and terrestrial links
Authors: H. Obata, K. Ishida, J. Funasaka, K. Amano
Venue: Proceedings of the 2000 International Conference on Network Protocols (2000)

As the Internet users increase, asymmetric networks which provide asymmetric bandwidth or delay for the uplink and downlink have become a great attraction. However asymmetric networks which use both terrestrial and satellite links at the same time have not been adequately investigated. Therefore, this paper proposes a new formula for TCP performance evaluation for the asymmetric networks. Using this evaluation formula, we calculate the throughput of TCP Reno over the asymmetric networks taking slow start into account. The calculation results are compared with the following: (1) the value based on an existing theoretical formula, (2) the outputs of simulation by NS (Network Simulator), and (3) the experimental results using VSAT (Very Small Aperture Terminal) satellite communication system for satellite links and the Internet for terrestrial links. As a result, it is shown that the new formula is more precise than the one already proposed.