ppxscal/embedding_network huggingface dataset:
Hierarchical reliable multicast: performance analysis and placement of proxies
Authors: Athina P. Markopoulou, Fouad A. Tobagi
Venue: Proceedings of NGC 2000 on Networked group communication (2000)

The use of proxies for local error recovery and congestion control is a scalable technique used to overcome a number of well-known problems in Reliable Multicast (RM). The idea is that the multicast delivery tree is partitioned into subgroups that form a hierarchy rooted at the source, hence the term Hierarchical Reliable Multicast (HRM). For each subgroup, there is a designated node, the proxy, which is responsible for collecting the feedback from the subgroup and for locally re-transmitting the lost packets. The performance of any RM protocol is affected by the underlying multicast routing tree and its loss characteristics. Furthermore, the performance of the HRM approach, in particular, strongly depends on the appropriate partitioning of the tree and the selection of proxies. In this paper, we first model the HRM problem, then define and compute appropriate performance metrics and finally give insights on the optimal location of proxies.
Parallel Implementation of Self-Organizing Map on the Partial Tree Shape Neurocomputer
Authors: Pasi Kolinummi, Pasi Pulkkinen, Timo Hämäläinen, Jukka Saarinen
Venue: Neural Processing Letters (2000)

A parallel mapping of self-organizing map (SOM) algorithm is presented for a partial tree shape neurocomputer (PARNEU). PARNEU is a general purpose parallel neurocomputer that is designed for soft computing applications. Practical scalability and a reconfigurable partial tree network are the main architectural features. The presented neuron parallel mapping of SOM with on-line learning illustrates a parallel winner neuron search and a coordinate transfer that are performed in the partial tree network. Phase times are measured to analyse speedup and scalability of the mapping. The performance of the learning phase in SOM with a four processor PARNEU configuration is about 26 MCUPS and the recall phase performs 30 MCPS. Compared to other mappings done for general purpose neurocomputers, PARNEU's performance is very good.
FlyCam: practical panoramic video
Authors: Jonathan Foote, Don Kimber
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

This demonstration presents a computationally and materially inexpensive system for panoramic video imaging. Digitally combining images from an array of inexpensive video cameras results in a wide-field panoramic camera, from inexpensive off-the-shelf- hardware. Digital processing both corrects lens distortion and seamlessly merges images into a panoramic video image. Electronically selecting a region of this results in a rapidly steerable &ldquo;virtual camera.&rdquo;
Unionization of professionals in data processing: an assessment of recent trends
Authors: Theodor D. Sterling
Venue: Communications of the ACM (1982)

The needs of management, unions, employees, and computer professionals combined with existing practices of Labor Relations Boards and the various divisions in the Departments of Labor have combined to create a unique array of social conflicts. At the root are management's interest in keeping many skills in data processing and computing out of bargaining units and the union's interest in including as many of these skills as possible. There is also conflict between past strategies guiding labor relations and the structure and function of professional work in modern organizations. Two recent developments are analyzed: (1) The FAA's success in keeping airports operational with the help of computer-controlled air flow procedures; (2) Management's successful bids to exclude professional engineers working in data processing jobs from bargaining units. At the same time, the National Labor and Mediation Boards have rejected attempts to define data processing jobs including highly skilled systems analysts as a separate craft or class for representation purposes while granting such status to engineers in similar employment situations. If this principle of exclusion from unions of licensed and certified professionals who are doing DP work is established in North America, it may lead to increased labor unrest in many highly automated and data processing industries.
Control procedures for data communication&mdash;an ASA progress report
Authors: Gerhard Salton
Venue: Communications of the ACM (1966)

Sectional Committee X.3 of the American Standards Association, has charged one of its task groups, X3.3.4, with the responsibility to &ldquo;Define and specify functional control requirements and characteristics governing the operation of digital data generating and receiving systems interconnected by communication system.&rdquo; This effort is primarily directed toward systems employing the American Standard Code for Information Interchange (ASCII). This paper represents a progress report on the work of this group toward a proposal for national and international standardization in the field of control procedures. It describes both the old and new work of the task group. The new work is presented in detail, while the work that has been presented in earlier papers [&ldquo;Control Procedures for Data Communication,&rdquo; Task Group document X3.3.4/44, May 1964: &ldquo;Transparent-Mode Control Procedures for Data Communication,&rdquo; Task Group document X3.3.4/58, December, 1964: Comm. ACM 8 (Apr. 1965), 203-206; &ldquo;Control Procedures for Data Communication,&rdquo; Task Group document X3.3.4/60, March, 1965] is retained here in summary form. Many of the concepts and principles described herein have been submitted to the International Organization for Standardization via earlier papers and are now embodied in working papers of that organization.
Integration of QoS-Enabled Distributed Object Computing Middleware for Developing Next-Generation Distributed Application
Authors: Yamuna Krishnamurthy, Vishal Kachroo, David A. Karr, Craig Rodrigues, Douglas C. Schmidt
Venue: Proceedings of the ACM SIGPLAN workshop on Languages, compilers and tools for embedded systems (2001)

This paper describes the integration of QoS-enabled distributed object computing (DOC) middleware for developing next-generation distributed applications. QoS-enabled DOC middleware facilitates ease of development and deployment of applications that can leverage the underlying networking technology or end-system QoS architecture. This paper also describes the development of a demonstration application utilizing QoS-enabled middleware to control the dissemination of Unmanned Air Vehicle (UAV) data throughout a ship.
Analysis of an algorithm for real time garbage collection
Authors: Philip L. Wadler
Venue: Communications of the ACM (1976)

A real time garbage collection system avoids suspending the operations of a list processor for the long times that garbage collection normally requires by performing garbage collection on a second processor in parallel with list processing operations, or on a single processor time-shared with them. Algorithms for recovering discarded list structures in this manner are presented and analyzed to determine sufficient conditions under which the list processor never needs to wait on the collector. These techniques are shown to require at most twice as much processing power as regular garbage collectors, if they are used efficiently. The average behavior of the program is shown to be very nearly equal to the worst-case performance, so that the sufficient conditions are also suitable for measuring the typical behavior of the algorithm.
Information dissemination and publication control
Authors: Gerard Salton
Venue: Communications of the ACM (1966)

The present issue contains a &ldquo;Forum on Algorithms&rdquo; dealing with some of the problems which arise in connection with the algorithm policy of the Communications. Specifically, many ACM members believe that a policy which designates only one language (ALGOL) as appropriate for publication purposes is too restrictive, particularly when this language is not accessible to many members and may not, moreover, be especially well suited for the description of many types of problems. This feeling is reflected in Professor Perlis' comments when he suggests that several languages should be acceptable &ldquo;one language being selected for each &hellip; algorithmic activity, chosen for the lucidity with which it expresses the diverse data manipulations of that area.&rdquo;
Multi-center congestion estimation and minimization during placement
Authors: M. Wang, X. Yang, K. Eguro, M. Sarrafzadeh
Venue: Proceedings of the 2000 international conference on Computer-aided design (2001)

As technology advances, more and more issues need to be considered in the placement stage, e.g., wirelength, congestion, timing, coupling. It is very hard to consider all of them together at the same time. Thus it is good if we can optimize one cost function without affecting others. In this paper, we will study methods to optimize congestion in placement without inflicting degradations/violations in other objectives or constraint. We give a mathematical equation to predict the overflow within a region using a normal distribution approximation. According to experiments, this equation does give a good estimation of overflow. We used this equation to find the smallest regions which have enough routing resource to alleviate the congestion and propose the flexible expansion scheme in our multi-center congestion reduction (MC2R) algorithm. Experimental results show that generally there is a correlation between the amount of reduction in congestion and the amount of change made to the placement: the more we change the placement, the more reduction in congestion we will get. However, the flexible expansion scheme is very effective in helping us reduce congestion while making only little change to the placement. Comparing to the full expansion scheme (49% congestion reduction and 6.5% change in placement), the flexible expansion scheme together with MC2 R algorithm can reduce congestion by almost the same amount (42%) with much less change made to the placement. (1.8%).
Credentials for privacy and interoperation
Authors: Vicki E. Jones, Neil Ching, Marianne Winslett
Venue: Proceedings of the 1995 workshop on New security paradigms (1995)

We consider the problem of providing secure, private access to applications and data in a world-wide distributed client-server environment such as the Internet of the future. In such a system, the set of potential users of a service may extend far beyond the local community knowable to the application providing the service. Applications will not generally have prior knowledge of the individual making a request upon which an access control decision can be baed and furthermore, knowledge of an individual's identity may not be directly useful. We frame our discussion in the context of supporting credentials which are submitted with a request, and propose a list of desiderata for such credentials. We evaluate several well-known proposals for credentials, focusing on issues related to privacy and scalability, and then point out the research issues that remain before such schemes can be deployed in a world-wide environment with strong privacy guarantees.
Efficient message dispatch in object-oriented systems
Authors: Mayur Naik, Rajeev Kumar
Venue: ACM SIGPLAN Notices (2000)

Single dispatch involves performing at run-time a multi-way switch over the possible classes of the receiver. Most object-oriented systems implement this switch as an array lookup using a table-based technique or as a binary search using a tree-based technique. However, each of these is the best choice only under a particular circumstance; neither outperforms the other under all circumstances. In this paper, we present a time and space efficient implementation of the switch that employs the table-based technique when an array lookup outperforms a binary search and the tree-based technique when a binary search outperforms an array lookup. Further, when neither an array lookup nor a binary search is superior, our scheme blends the two techniques in a manner that gains the benefits of both without suffering the disadvantages of either. We relate our scheme to recent work and discuss extending it to implement multiple dispatch.
Formal Automatic Verification of Cache Coherence in Multiprocessors with Relaxed Memory Models
Authors: Fong Pong, Michel Dubois
Venue: IEEE Transactions on Parallel and Distributed Systems (2000)

State-based, formal methods have been successfully applied to the automatic verification of cache coherence in sequentially consistent systems. However, coherence in shared-memory multiprocessors under a relaxed memory model is much more complex to verify automatically. With relaxed memory models, incoming invalidations and outgoing updates can be delayed in each cache while processors are allowed to race ahead. This buffering of memory accesses considerably increases the amount of state in each cache and the complexity of protocol interactions. Moreover, because caches can hold inconsistent copies of the same data for long periods of time, coherence cannot be verified by simply checking that cached copies are identical at all times. This paper makes two major contributions. First, we demonstrate how to model and verify cache coherence under a relaxed memory model in the context of state-based verification methods. Frameworks for modeling the hardware and for generating correct memory access sequences driving the hardware model are developed. We also show correctness properties which must be verified on the hardware model. Second, we demonstrate a successful application of a state-based verification tool called SSM for the verification of the delayed protocol, an aggressive protocol for relaxed memory models. SSM is based on an abstraction technique preserving the properties to verify. We show that with classical, explicit approaches the verification of cache coherence is realistically unfeasible because of the state space explosion problem, whereas SSM is able to verify protocols both at both behavioral and message-passing levels.
Learning Algorithm and Retrieval Process for the Multiple Classes Random Neural Network Model
Authors: Jose Aguilar
Venue: Neural Processing Letters (2001)

Gelenbe has modeled neural networks using an analogy with queuing theory. This model (called Random Neural Network) calculates the probability of activation of the neurons in the network. Recently, Fourneau and Gelenbe have proposed an extension of this model, called multiple classes random neural network model. The purpose of this paper is to describe the use of the multiple classes random neural network model to learn patterns having different colors. We propose a learning algorithm for the recognition of color patterns based upon non-linear equations of the multiple classes random neural network model using gradient descent of a quadratic error function. In addition, we propose a progressive retrieval process with adaptive threshold values. The experimental evaluation shows that the learning algorithm provides good results.
Abstract data types and software validation
Authors: John V. Guttag, Ellis Horowitz, David R. Musser
Venue: Communications of the ACM (1978)

A data abstraction can be naturally specified using algebraic axioms. The virtue of these axioms is that they permit a representation-independent formal specification of a data type. An example is given which shows how to employ algebraic axioms at successive levels of implementation. The major thrust of the paper is twofold. First, it is shown how the use of algebraic axiomatizations can simplify the process of proving the correctness of an implementation of an abstract data type. Second, semi-automatic tools are described which can be used both to automate such proofs of correctness and to derive an immediate implementation from the axioms. This implementation allows for limited testing of programs at design time, before a conventional implementation is accomplished.
Parameterized MAC unit implementation
Authors: Ming-Chih Chen
Venue: Proceedings of the 2001 Asia and South Pacific Design Automation Conference (2001)

Ethernet communication devices, such as adapter, hub, bridge and switch, all follow IEEE 802.3 standard protocol. We have designed and implemented an integrated 10/100 Mbps Ethernet MAC (Medium Access Control) mechanism. The MAC unit is used to handle receive/transmit processes of network packet stream. To meet the requirement of different communication devices, we design an automatic MAC unit generator. Users can select the desired number of MAC units through parametric environment setup. To verify the application of MAC unit, we provide a 10/100 Mbps layer-2 switch simulator and an automatic test pattern generator. The FPGA demo system reveals the validity of the MAC unit.
Description of systems used for data transmission
Authors: S. Gorn
Venue: Communications of the ACM (1966)

Task Group X3.3.51 is working to develop proposals for standards relating to the performance of systems used for digital data transmission. It has published two tutorial papers which were submitted by the U.S.A. to the International Organization for Standardization. In the first paper&mdash;ISO/TC97/SC6(USA-7)30,2 May, 1964&mdash;the general area of system performance was discussed. In the second paper, ISO/TC97/SC6 (USA-11)60,3 March, 1965, discussed in some detail were two characteristics of system performance, namely, Transfer Rate of Information Bits (TRIB) and Residual Error Rate. The present paper, the task group's third tutorial paper, is devoted to &ldquo;System Description&rdquo; insofar as that topic relates to system performance. Reported are the results of some 14 discussions that have occurred in about 1 3/4 years (June 1964 through March 1966). Including normal turnover of personnel in the group, some 14 people have been involved in these discussions. At present, the members of the task group are associated with business equipment manufacturers, users groups, and suppliers of communication facilities and services in the proportions 5 to 3 to 1. Other groups have published papers which discuss system description. In April, 1965, a paper from Italy4 was published in which system description was discussed in relation to line control and communication system techniques. In May, 1965, a paper from France5 was published in which system description was discussed in relation to system performance. These papers have been an interesting source of information to X3.3.5. While considering system performance, X3.3.5 concluded that system performance standards cannot be developed and used fully without having an organized way of describing the hardware and conditions to which performance applies. While this may not be quite t
Using tagged MRI to reconstruct a 3D heartbeat
Authors: Idith Haber, Dimitris N. Metaxas, Leon Axel
Venue: Computing in Science and Engineering (2000)

Magnetic resonance imaging tissue tagging is a decade-old method that lets scientists follow the motion of a beating heart. The method described here reconstructs 3D motion from multiple 2D MRI images to find new information about the right ventricle.
Efficient and robust multiple access control for wireless multimedia services
Authors: Yu-Kwong Kwok, Vincent K. N. Lau
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

In this paper, we propose a new multiple access control (MAC) protocol for wireless distributed multimedia systems based on ATM, in which user demands are highly heterogeneous and can be classified as CBR, VBR, and ABR. Our protocol is motivated by two of the most significant drawbacks of existing protocols: (1) channel condition is ignored or not exploited, and (2) inflexible or biased time slots allocation algorithms are used. Indeed, existing protocols mostly ignore the burst errors due to fading and shadowing, which are inevitable in a mobile and wireless communication environment. A few protocols take into account the burst errors but just &ldquo;handle&rdquo; the errors in a passive manner. On the other hand, most of the existing protocols employ an inflexible or biased allocation algorithm such that over-provisioning may occur for a certain class of users at the expense of the poor service quality received by other users. Our proposed protocol, called SCAMA (synergistic channel adaptive multiple access), does not have these two drawbacks. The proposed protocol works closely with the underlying physical layer in that through observing the channel state information (CSI) of each mobile user, the MAC protocol first segregates a set of users with good CSI from requests gathered in the request contention phase of an uplink frame. The MAC protocol then judiciously allocates information time slots to the users according to their traffic types, CSI, urgency, and throughput, which are collectively represented by a novel and flexible priority function.
Scheduling on hierarchical clusters using malleable tasks
Authors: Pierre-François Dutot, Denis Trystram
Venue: Proceedings of the thirteenth annual ACM symposium on Parallel algorithms and architectures (2001)

The model of malleable task (MT) was introduced some years ago and has been proved to be an efficient way for implementing parallel applications. It considers a target application at a larger level of granularity than in other models (corresponding typically to numerical routines) where the tasks can themselves be executed in parallel. Clusters of SMP (symmetric Multi-Processors) are a cost effective alternative to parallel supercomputers. Such hierarchical clusters are parallel systems made from m SMP composed each by k identical processors. They are more and more popular, however, designing efficient software that tale full advantage of such systems remains difficult. This work describes a 2 &mdash; 2&divide;k approximation algorithm for scheduling a set of independent malleable tasks for the minimization of the parallel execution time, where k is a power of 2 (k > 2). For k = 2, a special treatment leads to the bound of 3/2 which is the best known for non hierarchical tasks. The algorithm presented here is a fully polynomial approximation scheme running in &Ogr;(nmk) time.
Fen&mdash;an axiomatic basis for program semantics
Authors: B. J. MacLennan
Venue: Communications of the ACM (1973)

A formal system is presented which abstracts the notions of data item, function, and relation. It is argued that the system is more suitable than set theory (or its derivatives) for the concise and accurate description of program semantics. It is shown how the system can be used to build composite data types out of simpler ones with the operations of rowing, structuring, and uniting. It is also demonstrated that completely new primitive types can be introduced into languages through the mechanism of singleton data types. Both deterministic and nondeterministic functions are shown to be definable in the system. It is described how the local environment can be modeled as a data item and how imperative statements can be considered functions on the environment. The nature of recursive functions is briefly discussed, and a technique is presented by which they can be introduced into the system. The technique is contrasted with the use of the paradoxical combinator, Y. The questions of local and global environments and of various modes of function calling and parameter passing are touched upon. The theory is applied to the proof of several elementary theorems concerning the semantics of the assignment, conditional, and iterative statements. An appendix is included which presents in detail the formal system governing webs and fen, the abstractions used informally in the body of the paper.