Most engineering and scientific phenomena, such as the surface of a landscape or the continuously changing temperature at a location are inherently infinite in space or time or both. We cannot measure all the data. Generally it is possible to record surface elevation values or the temperature only at some specific locations and times.

Interpolation and Approximation

The performance of most digital systems today is limited by their communication or interconnection, not by their logic or memory. As designers strive to make more efficient use of scarce interconnection bandwidth, interconnection networks are emerging as a nearly universal solution to the system-level communication problems for modern digital systems. 


Interconnection networks have become pervasive in their traditional application as processor-memory and processor-processor interconnect. Point-to-point interconnection networks have replaced buses in an ever widening range of applications that include on-chip interconnect, switches and routers, and I/O systems. 


In this book, the authors present in a structured way the basic underlying concepts of most interconnection networks and provide representative solutions that have been implemented in the industry or proposed in the research literature.

* Gives a coherent, comprehensive treatment of the entire field
* Presents a formal statement of the basic concepts, alternative design choices, and design trade-offs
* Provides thorough classifications, clear descriptions, accurate definitions, and unified views to structure the knowledge on interconnection networks
* Focuses on issues critical to designers

Table of Contents

Foreword
Foreword to the First Printing
Preface
Chapter 1 - Introduction
Chapter 2 - Message Switching Layer
Chapter 3 - Deadlock, Livelock, and Starvation
Chapter 4 - Routing Algorithms
Chapter 5 - CollectiveCommunicationSupport
Chapter 6 - Fault-Tolerant Routing
Chapter 7 - Network Architectures
Chapter 8 - Messaging Layer Software
Chapter 9 - Performance Evaluation
Appendix A - Formal Definitions for Deadlock Avoidance
Appendix B - Acronyms
References
Index

Interconnection Networks

Current state-of-the-art on-chip networks provide efficiency, high throughput, and low latency for one-to-one (unicast) traffic. The presence of one-to-many (multicast) or one-to-all (broadcast) traffic can significantly degrade the performance of these designs, since they rely on multiple unicasts to provide one-to-many communication. This results in a burst of packets from a single source and is a very inefficient way of performing multicast and broadcast communication. This inefficiency is compounded by the proliferation of architectures and coherence protocols that require multicast and broadcast communication. In this paper, we characterize a wide array of on-chip communication scenarios that benefit from hardware multicast support. We propose Virtual Circuit Tree Multicasting (VCTM) and present a detailed multicast router design that improves network performance by up to 90\% while reducing network activity (hence power) by up to 53%.Our VCTM router is flexible enough to improve interconnect performance for a broad spectrum of multicasting scenarios,and achieves these benefits with straightforward and inexpensive extensions to a state-of-the-art packet-switched router.

Virtual Circuit Tree Multicasting: A Case for On-Chip Hardware Multicast Support

This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols.

https://www.mdpi.com/1424-8220/14/1/795/pdf

Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

Error resiliency schemes in H.264/AVC standard

This paper presents an efficient routing and flow control mechanism to implement multidestination message passing in wormhole networks. It is targeted to situations where the size of message data is very small, like in invalidation and update messages in distributed shared-memory multiprocessors (DSMs) with hardware cache coherence. The mechanism is a variation of tree-based multicast with pruning to avoid deadlocks. The new scheme does not require that the destination addresses in a given multicast message be ordered, thereby avoiding any ordering overhead. It allows messages to use any deadlock-free routing function and only requires one startup for each multicast message. The new scheme has been evaluated on several k-ary n-cube networks under synthetic loads. The results show that the proposed scheme is faster than other multicast mechanisms when the multicast traffic is composed of short messages.

An efficient implementation of tree-based multicast routing for distributed shared-memory multiprocessors

Last generation video encoding standards increase computing demands in order to reach the limits on compression efficiency. This is particularly the case of H.264/AVC specification that is gaining interest in industry. We are interested in applying parallel processing to H.264 encoders in order to fulfill the computation requirements imposed by stressing applications like video on demand, videoconference, live broadcast, etc. Given a delivered video quality and bit rate, the main complexity parameters are image resolution, frame rate and latency. These parameters can still be pushed forward in such a way that special purpose hardware solutions are not available. Parallel processing based on off-the-shelf components is a more flexible general purpose alternative. In this work we propose a hierarchical parallelization of H.264 encoders very well suited to low cost clusters. Our proposal uses MPI message passing parallelization at two levels: GOP and frame. The GOP level encodes simultaneously several groups of consecutive frames and the frame level encodes in parallel several slices of one frame. In previous work we found that GOP parallelism alone gives good speed-up but imposes very high latency, on the other side frame parallelism gets less efficiency but low latency. Combining both approaches we obtain a compromise between speed-up and latency and then a broader spectrum of applications can be covered.

Hierarchical Parallelization of an H.264/AVC Video Encoder

Monitoring pest insect populations is currently a key issue in agriculture and forestry protection. At the farm level, human operators typically must perform periodical surveys of the traps disseminated through the field. This is a labor-, time- and cost-consuming activity, in particular for large plantations or large forestry areas, so it would be of great advantage to have an affordable system capable of doing this task automatically in an accurate and a more efficient way. This paper proposes an autonomous monitoring system based on a low-cost image sensor that it is able to capture and send images of the trap contents to a remote control station with the periodicity demanded by the trapping application. Our autonomous monitoring system will be able to cover large areas with very low energy consumption. This issue would be the main key point in our study; since the operational live of the overall monitoring system should be extended to months of continuous operation without any kind of maintenance (i.e., battery replacement). The images delivered by image sensors would be time-stamped and processed in the control station to get the number of individuals found at each trap. All the information would be conveniently stored at the control station, and accessible via Internet by means of available network services at control station (WiFi, WiMax, 3G/4G, etc.).

https://www.mdpi.com/1424-8220/12/11/15801/pdf

Monitoring Pest Insect Traps by Means of Low-Power Image Sensor Technologies

Networks of workstations are rapidly emerging as a cost-effective alternative to parallel computers. Switch-based interconnects with irregular topologies allow the wiring flexibility, scalability and incremental expansion capability required in this environment. The irregularity also makes routing and deadlock avoidance on such systems quite complicated. Current proposals avoid deadlock by removing cyclic dependencies between channels. As a consequence, many messages are routed following non-minimal paths, increasing latency and wasting resources. In this paper, we propose a general methodology for the design of adaptive routing algorithms for networks with irregular topology. These routing algorithms allow messages to follow minimal paths in most cases, reducing message latency and increasing network throughput. The methodology is based on the application of the theory of deadlock avoidance proposed in [14], which increases routing flexibility by allowing cyclic dependencies between channels. As an example of application, we propose an adaptive routing algorithm for Autonet. It can be implemented either by duplicating physical channels or by splitting each physical channel into two virtual channels. In the former case, the implementation does not require a new switch design. It only requires changing the routing tables and adding links in parallel with existing ones, taking advantage of spare switch ports. In the latter case, a new switch design is required but the network topology is not changed. Preliminary evaluation results show that the new routing algorithm is able to increase throughput for random traffic by a factor of up to 2.8 with respect to the original algorithm, also reducing latency.

Efficient Adaptive Routing in Networks of Workstations with Irregular Topology

During the last two decades Red Palm Weevil (RPW, Rynchophorus Ferrugineus) has become one of the most dangerous threats to palm trees in many parts of the World. Its early detection is difficult, since palm trees do not show visual evidence of infection until it is too late for them to recover. For this reason the development of efficient early detection mechanisms is a critical element of RPW pest management systems. One of the early detection mechanisms proposed in the literature is based on acoustic monitoring, as the activity of RPW larvae inside the palm trunk is audible for human operators under acceptable environmental noise levels (rural areas, night periods, etc.). In this work we propose the design of an autonomous bioacoustic sensor that can be installed in every palm tree under study and is able to analyze the captured audio signal during large periods of time. The results of the audio analysis would be reported wirelessly to a control station, to be subsequently processed and conveniently stored. That control station is to be accessible via the Internet. It is programmed to send warning messages when predefined alarm thresholds are reached, thereby allowing supervisors to check on-line the status and evolution of the palm tree orchards. We have developed a bioacoustic sensor prototype and performed an extensive set of experiments to measure its detection capability, achieving average detection rates over 90%.

https://www.mdpi.com/1424-8220/13/2/1706/pdf

Manuel P. Malumbres

Papers

An efficient implementation of tree-based multicast routing for distributed shared-memory multiprocessors

Hierarchical Parallelization of an H.264/AVC Video Encoder

Monitoring Pest Insect Traps by Means of Low-Power Image Sensor Technologies

Efficient Adaptive Routing in Networks of Workstations with Irregular Topology

On the Design of a Bioacoustic Sensor for the Early Detection of the Red Palm Weevil