Abstract: This paper presents an algorithm to compute reliability measures on a stochastic network in which both nodes and links can fail. The measures considered are the probability that nodes s and t can communicate for all node pairs s and t, the probability that all operative node pairs can communicate, and the expected number of node pairs communicating. It also computes the latter two measures when all communication must proceed through a root node. A specialized version of the algorithm is given for networks in which only nodes can fail.

Abstract: A demand access broadcast transmission method and means is capable of supporting random port access and any-to-any transmission at very high data rates. A communication medium (FIG. 2) formed from an inverted tree network of nodes (1, 18, 22) and full duplex connecting links (13, 17, 19) permits the establishment of a path lock up-link through the network from a demanding port to a root node on a first-come first-serve demand access basis with arbitration at each distinct tree node level (FIG. 3). Broadcast transmission is perfected down-link over all fan-out paths from the root node. Collision is avoided by locking a path to a port and by limiting race conditions among active ports to only the leading edges of messages. Thus, relinquishment of a broadcast channel overlapped with transmission of a message does not result in path seizure since the occurrence of message leading edges is the singular path connection invoking event.

Abstract: Reciprocating tachycardias due to reentry either within the atrioventricular (AV) node or using an accessory AV pathway are a common cause of paroxysmal supraventricular tachycardia in hum...

Abstract: Many algorithms for finding orderings for sparse symmetr ic matrices operate on the corresponding undirected graph. These algorithms often require one or more \"start ing nodes,\" and for some algorithms experience suggests tha t nodes which are at maximum or nearly maximum distance apar t are good candidates [4, 611]. In a recent paper, Gibbs et al. [8] provide a novel heuristic algorithm for finding such nodes. Our objective in this paper is to provide a well-structured flexible implementat ion of this algori thm which includes some .modifications tha t appear to improve its performance. We include some experiments demonstra t ing the effect of various modifications to the original algorithm. We now give some formal definitions and a precise s ta tement of the problem. Let G ffi (X, E) be an undirected graph with the set X of nodes and the set E of undirected edges represented as unordered pairs of nodes. A path of length k is an ordered set of distinct nodes (Xo, x l , . . . , Xk) where {x,-1, x,) E E for 1 _< i _ k. A graph is connected if for each pair of distinct nodes there is a path joining them. Throughou t this paper, graphs are assumed to be connected unless we state otherwise. Consider a connected graph G. The distance d(x, y) between two nodes x and y in G is defined to be the length of a shortest pa th connecting them. Following Berge [2], we define the eccentricity of a node x to be the quant i ty l(x) ffi max{d(x, y) [ y E X}.

Abstract: In this paper a new class of network synchronization procedures, called Resynch Procedures, is described. A resynch procedure is a mechanism for effectively bringing all nodes of a distributed network to a known state simultaneously, despite arbitrary finite delays between nodes. The procedures presented have the interesting property that no time-outs are required. One use of a resynch procedure is to implement a network protocol that can guarantee that no packets will be lost and no duplicate packets will be inadvertently received, despite arbitrary node and link failures. This appears to be the first demonstration that such fail-safe protocols exist.

Abstract: A multiloop communications system and a method of routing data between stations is disclosed. The communications system has a plurality of interconnected communications loops, each of the loops including a ring-connected set of nodes providing data flow unidirectionally from one node to the next, each of the nodes being capable of passing data through itself along its loop, extracting data from its loop or injecting data into its loop. A first subset of each loop's set of nodes are local nodes which interface a station to its respective loop. A second subset of each loop's set of nodes are gateway nodes which interface to a gateway node of another of the loops. Each of the stations has a logical address unique within the system and each of the nodes has a functional address unique within each node's respective loop. A first station transmits data to a second station via the first station's local node, the local node forming a packet including the functional address of a node providing a route to the second station and further including the logical address of the second station. If the path to the second station includes a transfer to another loop, the gateway node on the transmitting loop transfers the logical address of the second station to the gateway node of the receiving loop. The gateway node of the receiving loop forms a new packet of data utilizing the logical address of the second station and a table which specifies the functional address of the route to be taken to second station. The system and method additionally provides for alternate routing in the case when the most direct path between the transmitting and receiving stations is inoperative.

Abstract: A communications system and network wherein communications links between subscribers are established by retrodirective oscillating loops between each subscriber and a node station. Provision is also made for establishment of retrodirective oscillating loops between nodes so that remotely located subscribers can communicate. Information is transmitted between subscribers by using a mixing process in the node whereby information transmitted from one subscriber to a node is transferred to a carrier signal transmitted between nodes or between a second node and another subscriber. A sampling technique is also described for use in the node which greatly minimizes the amount of apparatus required to implement the mixing process.

Abstract: A plurality of digital data processing systems are interconnected as nodes in a telecommunication network When two intelligent nodes are conneected and one local node determines that a process which it is executing requires the use of resources held at the second remote node, the local system sends a request to the remote system It is desirable that the remote system handle the request from the local system as it handles all other requests so that source integrity is maintained The local system, in response to a request from a local application program which it is sevicing, sends a corresponding transaction request along a communication link to the remote system This transaction request passes directly from node to node without going through any intermediate controller The remote system receives the request and creates a new unit of work The remote system then performs the unit of work and sends the result back to the local node The local system receives the result and returns it to the requesting application program

Abstract: The original routing algorithm of the ARPANET, in service for over a decade, has recently been removed from the ARPANET and replaced with a new and different algorithm. Although the new algorithm, like the old, is a distributed, adaptive routing algorithm, it is not similar to the old in any other important respect. In the new algorithm, each node maintains a data base describing the delay on each network line. A shortest-path computation is run in each node which explicitly computes the minimum-delay paths (based on the delay entries in the data base) from that node to all other nodes in the network. The average delay on each network line is measured periodically by the nodes attached to the lines. These measured delays are broadcast to all network nodes, so that all nodes use the same data base for performing their shortest-path computations. The new routing algorithm was extensively tested on the ARPANET before being released. This paper describes the algorithm and summarizes the results of these tests.

Abstract: Lemoine (Lemoine, A. 1977. Networks of queues—a survey of equilibrium analysis. Management Sci. 24 464–481.) studies sojourn times in acyclic, Jackson networks as part of his survey of equilibrium results. In his paper, he argues that a particular customer has a sojourn time at node i that is independent of his remaining sojourn time in the network given that the customer transfer from node i to node j. This assumption is then used to derive a set of equations involving the Laplace-Stieltjes transform of the sojourn times at each node from which several properties of sojourn times are determined. In a private communication, Mitrani (Mitrani, I. 1978. A critical note on a result of Lemoine. Private communication.) argues that the independence assumption is in error and provides a heuristic argument based on a four node, acyclic, Jackson network. From this, Mitrani concludes that the sojourn time in such networks is still an unsolved problem. We make Mitrani's argument rigorous, using some new results on so...

Abstract: In applying finite-difference techniques to flow field problems, the accuracy attained for a fixed number of node points can be improved using unequally-spaced node points. The distribution of these node points is chosen here by minimizing a measure of local truncation error with respect to the parameters which define a transformation between the computational space of equally-spaced node points and the physical space of unequally-spaced node points. The problem then becomes a nonlinear programming problem. Numerical results are presented for two one-dimensional test problems: the Blasius boundary layer problem and the inviscid Burgers' equation.

Abstract: A historical note is presented on the Virchow-Troisier node, which is known as Virchow's node in the United States and most continental countries and as the node of Troisier in France.

Abstract: A data switching node for the simultaneous high speed transmission of data originating from a plurality of source data switching units to a plurality of destination data switching units connected via time bus interface on a looped unidirectional time bus wherein the total information carrying capacity of the node is time multiplexed into separate data channels. Further the time bus interfaces comprise means to vary the number of data channels and their frequency of repetition, to share common channels, to detect between successful and unsuccessful transmissions, to store unsuccessful transmissions for retransmission, to transmit to several destinations at the same time, to monitor load conditions, to detect transmission and other errors on the node and to inform the node controller accordingly.

Abstract: This paper presents a formal scheme for addressing base and apex nodes in SW-banyan networks. This scheme is used for routing packets in the network. Packet-switching, in conjunction with the the circuit-switch mode of operation, offers a very flexible and powerful mechanism for interprocess communication in the multiprocessor architectures based on the banyan networks. Finally, a fault-tolerent scheme for re-routing the packets in the network is presented, in case the packet encounters a faulty node in its path.

Abstract: For use in a multi-node digital network wherein the local clocks of all the nodes are required to be maintained in synchronism, and corrections are required to be effected for changes in propagation times of inter-node links. A clock deviation at either of two link-connected nodes is oppositely detected at both nodes, and this results in each node transmitting, in place of a normal "do-nothing" signal, an "advance" or a "retard" signal (i.e. opposite types) to the other to correct for the deviation. Each signal transmitted is allowed to be operative on the clock at the receiving node only if no other link, terminated on that node, is producing a contrary signal. Thus the clock of the node which has drifted is subjected to correction by a signal from the partner node. As regards a change in propagation-delay of the link (same for each direction of transmission) this results in both nodes of the effected link transmitting identical "advance" or "retard" signals to the partner. These signals are assessed at each node as a demand in each case to similarly adjust the timing off-set appertaining to the frame alignment signal.

Abstract: A system in which a plurality of data processing systems are interconnected as nodes in a telecommunication network. When two inteliigent nodes are connected and one local node determines that a process requires the use of resources held at the second remote node, the local system sends a request to the remote system. The remote system wants to handle the request as it handles all other requests so that source integrity is maintained. The local system in response to the local request sends it along a communication link to the remote system. The remote system receives the request and creates a new unit of work. The remote system then performs the unit of work and sends the result back to the local node. The local system receives the result and returns It to the requesting application process.

Abstract: A transaction terminal system includes a user accessible terminal coupled by a message transmission link to a remote controller and incorporates a potential user authentication combination based on an encryption check and arranged so that the crictical encryption key is not resident nor is transmitted overtly to the user accessible terminal. The potential user enters into the terminal a transaction identifier and a first message from a card together with a second memorized message. The two messages are combined in the terminal to provide a key which is used to encrypt the transaction identifier. The identifier is transmitted to the controller, with and without encryption by their particular key where the identifier is encrypted by a key stored in the controller and a compari- ! son is performed between the two encrypted forms to test for validity of the input and an acceptance signal is transmitted back to the terminal. Other tests can be performed as to the validity of the transaction and the status of the terminal and the transmission can be overlayed by levels of encryption and decryption. The controller may form part of a host computer or of an intermediate node or both and authentication may be performed at the node when the host computer is off-line.

Abstract: This paper presents two algorithms for determining the most reliable paths of a communication network, taking into account both the reliabilities of nodes and links. A network is modeled by a linear graph. The first algorithm adapts a node labeling scheme; second is based on the shortest-path matrix algorithm. Both algorithms can be applied to oriented and nonoriented nonsymetric networks. The numerical examples confirm that both algorithms efficiently handle networks with hundreds of nodes and edges. The total amount of computation, expressed by the number of multiplications and comparisons, increases in the labeling procedure with the square of the number of nodes, and in the matrix method with the cube of the number of nodes.

Abstract: The benefits of general-purpose local networks are discussed and the requirements that such networks need to satisfy are defined. A generic network architectural model is described and the major design parameters identified. The role of the local network is to provide network transparency for a multiplicity of computer devices. How well this role is performed is a function of the protocol design and implementation.MITRE's Cablenet is one of several experimental cable-bus networks employing coaxial cable as a shared wideband transmission medium, and using microprocessor based interface units. This paper presents a protocol architecture design based on local network characteristics and the extensive computational capabilities expected from the next generation of microprocessors. We have designed a Flexible Transport Protocol which allows our cable-bus access node to assume a wide range of characteristics; these characteristics can be chosen judiciously to fulfil the needs of a wide spectrum of subscribers.

Abstract: PURPOSE:To simplify hardware by fixedly allocating free time slots for communication only when time slots are to be used. CONSTITUTION:Loop transmission line 4 is provided with time slot control part 5 and nodes 6-1-6-i. To respective nodes, DTE parts 3-1, 3-2-3-i, such as a computer and terminal device, are connected. Through this loop transmission line 4, frame data of constitutions roughly classified into time slot group I used for communication between the nodes and time slot control part 5 and time slot group II used for communication between nodes. Time slot control part 5 decodes a node request from a node to store the inuse state of the time slots and, when a request for communication from one node to another node is sent, allocates time slots required for that, so that the transmission line can effectively be used.

Abstract: Algorithms are described here which are suitable for control of a distributed network of signal processors which are interconnected with dedicated paths using decentralized routing control. This paper discusses the algorithm used to implement the processing required at the switching node processor, which can be realized with any of several LSI technologies. Although centralized systems are more efficient in terms of hardware, a single failure in the controller may disable the entire network. This distributed network is implemented with a crossbar switch at each node which facilitates the simultaneous utilization of multiple paths in the network. Index Terms-Computer networks, data routing algorithms, digital signal processing, distributed processing, signal processing networks.

Abstract: For the comparative study of gene regulation, the concept of a controller node is made use of. A controller node is the set of molecular components directly intervening in the control of RNA derived from a functional unit of gene action (abbreviated fuga). The complexity of a controller node is defined here as the number per fuga of distinct components included in the controller node relevant to a given fuga. Two types of controller node are distinguished: transcriptional and processing. The complexity of a transcriptional controller node is the sum of distinct receptor sequences in the fuga, distinct regulator molecules that interact with them, and distinct effector molecules or modifying enzymes that interact with the regulator molecules. Likewise, processing controller node complexity is the sum of distinct receptor sequences on an intact nuclear RNA transcript, distinct processor molecules that interact with the receptors, and distinct effector molecules or modifying enzymes that interact with the processors. For valid comparisons between widely different organisms, values for transcriptional and processing controller node complexity might in the future be combined to yield a value for conjugate controller node complexity. Some conventions for evaluating controller node complexity are proposed and are applied to a few bacterial operons. Particular conditions of the application of the concept to eukaryote fugas are discussed. Average controller node complexity per organism or per genetic subsystem is a measure of the amount of gene coordination. This value would also reflect the hierarchical complexity of organisms, if it increased during progressive evolution.

Abstract: This paper presents methods for the time-oriented evaluation of special GERT networks. If every node of a GERT network has an exclusive-or entrance and a stochastic exit (so-called STEOR node), then a Markov renewal process can be assigned to this activity network. In this case, the quantities of interest in project scheduling may be determined from the renewal functions of the process. In addition, GERT networks containing “non-STEOR nodes” are treated where the non-STEOR nodes are allowed to occur only within special subnetworks, called basic element structures. Numerical tests have shown that in most cases the methods described consume less computing time than simulation.

Abstract: : This paper presents three algorithms for obtaining maximum flow in a network using distributed computation. Each node in the network has memory and processing capabilities and coordinates the algorithm with its neighbors using control messages. Each of the last two versions requires more sophistication at the nodes than the previous one, but on the other hand employs less communication. (Author)

Abstract: In the search for speed and computing power, many researchers in computer science have turned to networks of computers as a possible solution. 1 , 5 , 8 , 14 , 9 These networks consist of minicomputers connected by links across which communication between processors occurs. In homogeneous networks, the computer at each node is identical to the others, with the possible exception of peripherals. Each processor has its own local memory, does not share memory with any other processor, and communicates with other processors via message passing. In order to fully utilize the speed and power inherent in a network, emphasis must be placed on the development of parallel (as opposed to sequential) algorithms.