waashk/acm huggingface dataset:
dasp: a general-purpose mimd parallel computer using distributed associative processing  this paper presents a general purpose mimd (multiple instruction stream multiple data stream) loosely-coupled parallel computer called dasp (distributed associative processor). the dasp organization partitions the communication and application functions. the communication functions are performed by custom-made communication handlers called network communication modules, while application functions are performed by any general purpose processor suitable for the application. the communication subsystem of dasp takes advantage of the properties of loosely-coupled mimd parallel computers: the very short inter-processor distances and the locality of task reference. by pipelining the time slices of the bus hierarchically with the cito (content induced transaction overlap) protocol, dasp provides virtual full-connectivity to the application processors without physical full connections; thus, its architecture exhibits a very high degree of extensibility and modularity. analytical and simulation results have validated the dasp approach. a prototype has been constructed and several algorithms have been successfully implemented on the prototype.  y. k. park c. walter h. yee t. roden s. berkovich
a comparative study of distributed resource sharing on multiprocessors  in this paper, we have studied the interconnection of resources to multiprocessors and the distributed scheduling of these resources. three different classes of interconnection networks have been investigated; namely, single shared bus, multiple shared buses, and networks with logarithmic delays such as the cube and omega networks. for a given network, the resource mapping problem entails the search of one (or more) of the free resources which can be connected to each requesting processor. to prevent the bottleneck of sequential scheduling, the type(s) and number(s) of resources desired by a processor are given to the network and it is the responsibility of the network to find the necessary resources and connect them to the processor. the addressing mechanism is, thus, distributed in the network. this is a generalization of conventional interconnection networks with routing tags in which all the resources are of different types.  benjamin w. wah
secure group communications using key graphs many emerging applications (e.g., teleconference, real-time information services, pay per view, distributed interactive simulation, and collaborative work) are based upon a group communications model, i.e., they require packet delivery from one or more authorized senders to a very large number of authorized receivers. as a result, securing group communications (i.e., providing confidentiality, integrity, and authenticity of messages delivered between group members) will become a critical networking issue.in this paper, we present a novel solution to the scalability problem of group/multicast key management. we formalize the notion of a secure group as a triple (_u,k,r_) where _u_ denotes a set of users, _k_ a set of keys held by the users, and _r_ a user-key relation. we then introduce key graphs to specify secure groups. for a special class of key graphs, we present three strategies for securely distributing rekey messages after a join/leave, and specify protocols for joining and leaving a secure group. the rekeying strategies and join/leave protocols are implemented in a prototype group key server we have built. we present measurement results from experiments and discuss performance comparisons. we show that our group key management service, using any of the three rekeying strategies, is scalable to large groups with frequent joins and leaves. in particular, the average measured processing time per join/leave increases linearly with the logarithm of group size. chung kei wong mohamed gouda simon s. lam
mobile power management for wireless communication networks  for fixed quality-of-service constraints and varying channel interference, how should a mobile node in a wireless network adjust its transmitter power so that energy consumption is minimized? several transmission schemes are considered, and optimal solutions are obtained for channels with stationary, extraneous interference. a simple dynamic power management algorithm based on these solutions is developed. the algorithm is tested by a series of simulations, including the extraneous-interference case and the more general case where multiple, mutually interfering transmitters operate in a therefore highly responsive interference environment. power management is compared with conventional power control for models based on fdma/tdma and cdma cellular networks. results show improved network capacity and stability in addition to substantially improved battery life at the mobile terminals.  john m. rulnick nicholas bambos
energy-effective issue logic  _the issue logic of a dynamically-scheduled superscalar processor is a complex mechanism devoted to start the execution of multiple instructions every cycle. due to its complexity, it is responsible for a significant percentage of the energy consumed by a microprocessor. the energy consumption of the issue logic depends on several architectural parameters, the instruction issue queue size being one of the most important. in this paper we present a technique to reduce the energy consumption of the issue logic of a high-performance superscalar processor. the proposed technique is based on the observation that the conventional issue logic wastes a significant amount of energy for useless activity. in particular, the wake-up of empty entries and operands that are ready represents an important source of energy waste. besides, we propose a mechanism to dynamically reduce the effective size of the instruction queue. we show that on average the effective instruction queue size can be reduced by a factor of 26% with minimal impact on performance. this reduction together with the energy saved for empty and ready entries result in about 90.7% reduction in the energy consumed by the wake-up logic, which represents 14.9% of the total energy of the assumed processor._  daniele folegnani antonio gonzalez
a measurement-based admission control algorithm for integrated services packet networks many designs for integrated service networks offer a bounded delay packet delivery service to support real-time applications. to provide bounded delay service, networks must use admission control to regulate their load. previous work on admission control mainly focused on algorithms that compute the worst case theoretical queueing delay to guarantee an absolute delay bound for all packets. in this paper we describe a _measurement- based_ admission control algorithm for _predictive_ service, which allows occasional delay violations. we have tested our algorithm through simulations on a wide variety of network topologies and driven with various source models, including some that exhibit long-range dependence, both in themselves and in their aggregation. our simulation results suggest that, at least for the scenarios studied here, the measurement-based approach combined with the relaxed service commitment of predictive service enables us to achieve a high level of network utilization while still reliably meeting the delay bound. sugih jamin peter b. danzig scott shenker lixia zhang
project exodus: experimental mobile multimedia deployment in atm networks  this paper reports on european commission sponsored research within the exodus project. the project carries out research in the context of the evolution towards umts and performs personal and terminal multimedia mobility experiments using fixed and wide-band radio access in an international atm network. after introducing the exodus platform and services, the paper presents an in-based functional model which is suitable for support of mobile multimedia services in atm networks. interworking and mobility management issues are discussed, and information flows for call handling are presented. the paper includes a presentation of the mobility management and enhanced inap protocols which have been developed by the exodus project.  j. c. francis d. v. polymeros g. l. lyberopoulos v. vande keere a. elberse p. rogl l. vezzoli
the effects of asymmetry on tcp performance  in this paper, we study the effects of network asymmetry on end-to-end tcp performance and suggest techniques to improve it. the networks investigated in this study include a wireless cable modem network and a packet radio network, both of which can form an important part of a mobile ad hoc network. in recent literature (e.g., [18]), asymmetry has been considered in terms of a mismatch in bandwidths in the two directions of a data transfer. we generalize this notion of bandwidth asymmetry to other aspects of asymmetry, such as latency and media-access, and packet error rate, which are common in wide-area wireless networks. using a combination of experiments on real networks and simulation, we analyze tcp performance in such networks where the throughput achieved is not solely a function of the link and traffic characteristics in the direction of data transfer (the forward direction), but depends significantly on the reverse direction as well. we focus on bandwidth and latency asymmetries, and propose and evaluate several techniques to improve end-to-end performance. these include techniques to decrease the rate of acknowledgments on the constrained reverse channel (ack congestion control and ack filtering), techniques to reduce source burstiness when acknowledgments are infrequent (tcp sender adaptation), and algorithms at the reverse bottleneck router to schedule data and acks differently from fifo (acks-first scheduling).  hari balakrishnan randy h. katz venkata n. padmanbhan
the (un)revised osi reference model in 1988, sc21, the iso committee responsible for the open systems interconnection (osi) reference model, determined that it was time to undertake revising iso 7498-1, the basic osi reference model. since the model had been published in 1984, this was in accordance with iso practice of reviewing and revising standards every five years, and there was good reason for considering the task. over the intervening five years, the groups developing the osi protocols had raised many questions about the architecture and these had been answered and documented in the approved commentaries [1994]. many of these commentaries contained information that could be usefully incorporated into the reference model itself. in addition, the addendum describing connectionless mode, i.e. datagrams, had been completed several years before and needed to be incorporated. there was also considerable demand for interworking connection- mode and connectionless mode communication, something not supported by the reference model or any architecture. also, when the original version of the reference model was frozen about 1983 some aspects of osi such as the upper layers were not well understood and were only described in the most cursory manner. and while connection-mode and connectionless mode had been brought within osi, there was no indication as to how broadcast and multicast were to be handled. thus, the revision might be able to provide a more comprehensive description of these areas.this paper describes how the revision was carried out, describes the changes and additions that were made, considers the effect and contribution this revision has made to our understanding, and describes the outstanding issues that were not addressed by this revision. john day
mac protocol and traffic scheduling for wireless atm networks  the medium access control (mac) protocol defined in the wireless atm network demonstrator (wand) system being developed within the project magic wand is presented. magic wand is investigating extensions of atm technology to cover wireless customer premises networks, in the framework of the advanced communications technologies and services (acts) programme, funded by the european union. the mac protocol, known as mascara, uses a dynamic tdma scheme, which combines reservation- and contention-based access methods to provide multiple access efficiency and quality of service guarantees to wireless atm terminal connections sharing a common radio channel. the paper focuses on the description of prados, a delay-oriented traffic scheduling algorithm, which aims at satisfying the requirements of the various traffic classes defined by the atm architecture. simulation results are presented to assess the performance of the proposed algorithm in scheduling transmission of variable bit rate connections.  nikos passas lazaros merakos dimitris skyrianoglou frederic bauchot gerard marmigere stephane decrauzat
data flow graph partitioning to reduce communication cost  this paper presents a cost-effective scheme for partitioning large data flow graphs. standard data flow machine architectures are assumed in this work. the objective is to reduce the overhead due to token transfers through the communication network of the machine. when this scheme is employed on large graphs, the load distribution on the rings of the data flow machine is also improved. a canonical form of a data flow graph is introduced to establish the relationship between the communication overhead and the size reduction of the partition cut-set. general lower estimates on the overhead are derived in terms of processing and transmission delay parameters of the machine. the method uses heuristics and an evaluation function to guide the partition algorithm. some implications of the proposed method on the organization of the data flow machines are discussed.  c. koutsougeras c. a. papachristou r. r. vemuri
z-net a microprocessor based local network  z-net, a microprocessor based local network recently announced by zilog, inc., is designed to provide a fourth choice which significantly reduces the effort involved in utilizing a local network. z-net is a collection of hardware and software layers that provide the flexibility needed to customize the network to a particular application without rewriting all of the software.  the z-net architecture is "ethernet"-like in that it provides a packet switched, single channel, contention based, multiple access network with fully distributed control. the advantages of this type of architecture have been proven in many research environments.  judy estrin
optimally adaptive, minimum-distance, circuit-switched routing in hypercubes  in circuit-switched routing, the path between a source and its destination is established by incrementally reserving all required links before the data transmission can begin. if the routing algorithm is not carefully designed, deadlocks can occur in reserving these links. deadlock- free algorithms based on dimension-ordered routing, such as the e-cube, exist. however, e-cube does not provide any flexibility in choosing a path from a source to its destination and can thus result in long latencies under heavy or uneven traffic. adaptive, minimum-distance routing algorithms, such as the turn model and the up preference algorithms, have previously been reported. in this article, we present a new class of adaptive, provably deadlock-free, minimum- distance routing algorithms. we prove that the algorithms developed here are optimally adaptive in the sense that any further flexibility in communication will result in deadlock. we show that the turn model is actually a member of our new class of algorithms that does not perform as well as other algorithms within the new class. it creates artificial hotspots in routing the traffic and allows fewer total paths. we present an analytical comparison of the flexibility and balance in routing provided by various algorithms and a comparison based on uniform and nonuniform traffic simulations. the extended up preference algorithm developed in this article is shown to have improved performance with respect to existing algorithms. the methodology and the algorithms developed here can be used to develop routing for other schemes such as wormhole routing, and for other recursively defined networks such as k-ary n-cubes.  ausif mahmood donald j. lynch roger b. shaffer
elections in the presence of faults  the news media often bombards the public with forecasts of election results. polls predict, sometimes years in advance; exit polls are more accurate, and unofficial tallies tend to be closer to the final results. if close elections are disputed, it may take the courts weeks to determine the actual outcome of an election. if the election is nearly unanimous, however, a few disputed votes can have no outcome on the final results. the time at which the final results may be known with certainty thus depends upon the accuracy of the forecast (the number of disputed votes), and the closeness of the election.  michael merritt
masking the overhead of protocol layering protocol layering has been advocated as a way of dealing with the complexity of computer communication. it has also been criticized for its performance overhead. in this paper, we present some insights in the design of protocols, and how these insights can be used to mask the overhead of layering, in a way similar to client caching in a file system. with our techniques, we achieve an order of magnitude improvement in end-to-end message latency in the horus communication framework. over an atm network, we are able to do a round-trip message exchange, of varying levels of semantics, in about 170 seconds, using a protocol stack of four layers that were written in ml, a high-level functional language. robbert van renesse
towards a taxonomy of computer architecture based on the machine data type view  existing taxonomies of computer architecture lack the descriptive tools to deal with the large variety of existing principles, features, and mechanisms of the existing spectrum of single processor, multi processor, and multi computer architectures. consequently, they lack the discriminating power to be able to taxonomize computer architecture. in the paper, a new approach toward a complete taxonomy is presented. the key to the taxonomy is to start with the dichotomy of 'operational principle' and 'hardware structure' as the foundation of a computer architecture and describe the constituents of the operational principle in terms of 'machine data types' consisting of 'machine data objects', their representations, and the functions applicable on the objects. the resulting taxonomy provides a systematic approach to the design of innovative computer architectures.  w. k. giloi
asymptotic resource consumption in multicast reservation styles  the goal of network design is to meet the needs of resident applications in an efficient manner. adding real-time service and point-to-multipoint multicast routing to the internet's traditional point-to-point best effort service model will greatly increase the internet's efficiency in handling point-to- multipoint real-time applications. recently, the rsvp resource reservation protocol has introduced the concept of "reservation styles", which control how reservations are aggregated in multipoint-to-multipoint real-time applications. in this paper, which is an extension of [9], we analytically evaluate the efficiency gains offered by this new paradigm on three simple network topologies: linear, m-tree, and star. we compare the resource utilization of more traditional reservation approaches to the rsvp reservation styles in the asymptotic limit of large multipoint applications. we find that in several cases the efficiency improvements scale linearly in the number of hosts.  danny j. mitzel scott shenker
markov analysis of the prma protocol for local wireless networks  prma (packet reservation multiple access) is a reservation-aloha access protocol specifically designed for wireless microcellular networks that handle both real-time and non-real-time traffic. we present a thorough analysis of this protocol, considering real-time traffic only, based on a suitable markov model. the size of the model is such that it can be directly used for an exact quantitative analysis of the system. in particular, we are able to analyze the packet dropping process, by evaluating both average and distribution measures. the latter are particularly useful to characterize the degradation caused to real-time traffic (e.g., voice) by the loss of consecutive packets. besides, we also derive from the markov model a qualitative analysis of the system stability, based on the equilibrium point analysis (epa) technique. by this technique, we characterize the system stability and analyze the effect on it of several system parameters (e.g., load, permission probability).  francesco lo presti vincenzo grassi
uniform access to internet directory services  as networks and internetworks of computers expand in size and scope, discovery and location of resources becomes a primary function of the networked computing environment. static tables describing network resources have been replaced by dynamic directory services, such as x.500 and the internet domain name system. these dynamic directory services provide more timely and accurate information about network resources than static tables.  a wide variety of services address various components of the resource discovery and location problem. these services can be loosely classified as either low-level protocols or high-level services. low-level protocols, such as rarp and icmp, are simple delivery protocols and provide limited information; high-level services, such as the internet domain name system and x.500, use complex delivery protocols to answer complex queries. neither class of directory service is appropriate in all situations. low-level services are too restrictive in the type of queries and information they support, while high- level services may be too expensive for some low-function networks.  d. comer r. e. droms
design and performance evaluation of an rra scheme for voice-data channel access in outdoor microcellular environments  in pcs networks, the multiple access problem is characterized by spatially dispersed mobile source terminals sharing a radio channel connected to a fixed base station. in this paper, we design and evaluate a reservation random access (rra) scheme that multiplexes voice traffic at the talkspurt level to efficiently integrate voice and data traffic in outdoor microcellular environments. the scheme involves partitioning the time frame into two request intervals (voice and data) and an information interval. thus, any potential performance degradation caused by voice and data terminals competing for channel access is eliminated. we consider three random access algorithms for the transmission of voice request packets and one for the transmission of data request packets. we formulate an approximate markov model and present analytical results for the steady state voice packet dropping probability, mean voice access delay and voice throughput. simulations are used to investigate the steady state voice packet dropping distribution per talkspurt, and to illustrate preliminary voice-data integration considerations.  allan c. cleary michael paterakis