2,131 research outputs found
Routing in turn-prohibition based feed-forward networks
Abstract. The application of queuing theory to communications systems often requires that the respective networks are of a feed-forward nature, that is they have to be free of cyclic dependencies. An effective way to ensure this property is to identify a certain set of critical turns and to prohibit their use. A turn is a concatenation of two adjacent, consecutive links. Unfortunately, current routing algorithms are usually not equipped to handle forbidden turns and the required extensions are nontrivial. We discuss the relevant issues for the example of the widely deployed Dijkstra algorithm. Then, we address the general case and introduce the Turnnet concept, which supports arbitrary combinations of routing algorithms with turn-prohibiting feed-forward mechanisms
On Cyclic Dependencies and Regulators in Time-Sensitive Networks
For time-sensitive networks, as in the context of
IEEE TSN and IETF Detnet, cyclic dependencies are associated
with certain fundamental properties such as improving availability
and decreasing reconfiguration effort. Nevertheless, the
existence of cyclic dependencies can cause very large latency
bounds or even global instability, thus making the proof of the
timing predictability of such networks a much more challenging
issue. Cyclic dependencies can be removed by reshaping
flows inside the network, by means of regulators. We consider
FIFO-per-class networks with two types of regulators: perflow
regulators and interleaved regulators (the latter reshape
entire flow aggregates). Such regulators come with a hardware
cost that is less for an interleaved regulator than for a perflow
regulator; both can affect the latency bounds in different
ways. We analyze the benefits of both types of regulators in
partial and full deployments in terms of latency. First, we
propose Low-Cost Acyclic Network (LCAN), a new algorithm
for finding the optimum number of regulators for breaking all
cyclic dependencies. Then, we provide another algorithm, Fixed-
Point Total Flow Analysis (FP-TFA), for computing end-to-end
delay bounds for general topologies, i.e., with and without cyclic
dependencies. An extensive analysis of these proposed algorithms
was conducted on generic grid topologies. For these test networks,
we find that FP-TFA computes small latency bounds; but, at
a medium to high utilization, the benefit of regulators becomes
apparent. At high utilization or for high line transmission-rates, a
small number of per-flow regulators has an effect on the latency
bound larger than a small number of interleaved regulators.
Moreover, interleaved regulators need to be placed everywhere
in the network to provide noticeable improvements. We validate
the applicability of our approaches on a realistic industrial timesensitive
network
Torii: Multipath Distributed Ethernet Fabric Protocol for Data Centers with Zero-Loss Path Repair
This paper describes and evaluates Torii, a layer-two data center network fabric protocol. The main features of Torii are being fully distributed, scalable, fault-tolerant and with automatic setup. Torii is based on multiple, tree-based, topological MAC addresses that are used for table-free forwarding over multiple equal-cost paths, and it is capable of rerouting frames around failed links on the fly without needing a central fabric manager for any function. To the best of our knowledge, it is the first protocol that does not require the exchange of periodic messages to work under normal conditions and to recover from link failures, as Torii exchanges messages just once. Moreover, another important characteristic of Torii is that it is compatible with a wide range of data center topologies. Simulation results show an excellent distribution of traffic load and latencies, similar to shortest path protocols
Torii: Multipath Distributed Ethernet Fabric Protocol for Data Centers with Zero-Loss Path Repair
This paper describes and evaluates Torii, a layer-two data center network fabric protocol. The main features of Torii are being fully distributed, scalable, fault-tolerant and with automatic setup. Torii is based on multiple, tree-based, topological MAC addresses that are used for table-free forwarding over multiple equal-cost paths, and it is capable of rerouting frames around failed links on the fly without needing a central fabric manager for any function. To the best of our knowledge, it is the first protocol that does not require the exchange of periodic messages to work under normal conditions and to recover from link failures, as Torii exchanges messages just once. Moreover, another important characteristic of Torii is that it is compatible with a wide range of data center topologies. Simulation results show an excellent distribution of traffic load and latencies, similar to shortest path protocols
Exact Worst-case Delay in FIFO-multiplexing Feed-forward Networks
In this paper, we compute the actual worst-case end-to-end delay for a flow in a feed-forward network of first-inâfirst-out (FIFO)-multiplexing service curve nodes, where flows are shaped by piecewise-affine concave arrival curves, and service curves are piecewise affine and convex. We show that the worst-case delay problem can be formulated as a mixed integer linear programming problem, whose size grows exponentially with the number of nodes involved. Furthermore, we present approximate solution schemes to find upper and lower delay bounds on the worst-case delay. Both only require to solve just one linear programming problem and yield bounds that are generally more accurate than those found in the previous work, which are computed under more restrictive assumptions
Site-Specific Rules Extraction in Precision Agriculture
El incremento sostenible en la produccioÌn alimentaria para satisfacer las necesidades de una poblacioÌn mundial en aumento es un verdadero reto cuando tenemos en cuenta el impacto constante de plagas y enfermedades en los cultivos. Debido a las importantes peÌrdidas econoÌmicas que se producen, el uso de tratamientos quiÌmicos es demasiado alto; causando contaminacioÌn del medio ambiente y resistencia a distintos tratamientos. En este contexto, la comunidad agriÌcola divisa la aplicacioÌn de tratamientos maÌs especiÌficos para cada lugar, asiÌ como la validacioÌn automaÌtica con la conformidad legal. Sin embargo, la especificacioÌn de estos tratamientos se encuentra en regulaciones expresadas en lenguaje natural. Por este motivo, traducir regulaciones a una representacioÌn procesable por maÌquinas estaÌ tomando cada vez maÌs importancia en la agricultura de precisioÌn.Actualmente, los requisitos para traducir las regulaciones en reglas formales estaÌn lejos de ser cumplidos; y con el raÌpido desarrollo de la ciencia agriÌcola, la verificacioÌn manual de la conformidad legal se torna inabordable.En esta tesis, el objetivo es construir y evaluar un sistema de extraccioÌn de reglas para destilar de manera efectiva la informacioÌn relevante de las regulaciones y transformar las reglas de lenguaje natural a un formato estructurado que pueda ser procesado por maÌquinas. Para ello, hemos separado la extraccioÌn de reglas en dos pasos. El primero es construir una ontologiÌa del dominio; un modelo para describir los desoÌrdenes que producen las enfermedades en los cultivos y sus tratamientos. El segundo paso es extraer informacioÌn para poblar la ontologiÌa. Puesto que usamos teÌcnicas de aprendizaje automaÌtico, implementamos la metodologiÌa MATTER para realizar el proceso de anotacioÌn de regulaciones. Una vez creado el corpus, construimos un clasificador de categoriÌas de reglas que discierne entre obligaciones y prohibiciones; y un sistema para la extraccioÌn de restricciones en reglas, que reconoce informacioÌn relevante para retener el isomorfismo con la regulacioÌn original. Para estos componentes, empleamos, entre otra teÌcnicas de aprendizaje profundo, redes neuronales convolucionales y âLong Short- Term Memoryâ. AdemaÌs, utilizamos como baselines algoritmos maÌs tradicionales como âsupport-vector machinesâ y ârandom forestsâ.Como resultado, presentamos la ontologiÌa PCT-O, que ha sido alineada con otras ontologiÌas como NCBI, PubChem, ChEBI y Wikipedia. El modelo puede ser utilizado para la identificacioÌn de desoÌrdenes, el anaÌlisis de conflictos entre tratamientos y la comparacioÌn entre legislaciones de distintos paiÌses. Con respecto a los sistemas de extraccioÌn, evaluamos empiÌricamente el comportamiento con distintas meÌtricas, pero la meÌtrica F1 es utilizada para seleccionar los mejores sistemas. En el caso del clasificador de categoriÌas de reglas, el mejor sistema obtiene un macro F1 de 92,77% y un F1 binario de 85,71%. Este sistema usa una red âbidirectional long short-term memoryâ con âword embeddingsâ como entrada. En relacioÌn al extractor de restricciones de reglas, el mejor sistema obtiene un micro F1 de 88,3%. Este extractor utiliza como entrada una combinacioÌn de âcharacter embeddingsâ junto a âword embeddingsâ y una red neuronal âbidirectional long short-term memoryâ.<br /
Securities Fraud Embedded in the Market Structure Crisis: High-Frequency Traders as Primary Violators
This Article analyzes approaches to attaching liability for securities fraud to high-frequency traders as primary violators in connection with the current market structure crisis. One of the manifestations of this crisis pertains to inadequate disclosure of advanced functionalities offered by trading venues, as exemplified by the order type controversy. The Articleâs analysis is applied to secret arrangements between trading venues and preferred traders, glitches and gaming, and the reach of the doctrine of market manipulation, and several relevant issues are also viewed from the standpoint of the integrity of the trading process. The Article concludes by arguing for a balanced approach to catching certain problematic practices of high-frequency traders as securities fraud
Applications
Volume 3 describes how resource-aware machine learning methods and techniques are used to successfully solve real-world problems. The book provides numerous specific application examples: in health and medicine for risk modelling, diagnosis, and treatment selection for diseases in electronics, steel production and milling for quality control during manufacturing processes in traffic, logistics for smart cities and for mobile communications
- âŠ