7 research outputs found
Gigabit Networks
This chapter summarizes what we have learned in the past decade of research into extremely high throughput networks. Such networks are colloquially referred to as Gigabit Networks in reference to the billion bit per second throughput regime they now operate in. The engineering challenges are in the integration of fast transmission systems and high-performance engineering workstations
The Influence of ATM on Operating Systems
The features of ATM offered many attractions to the application community, such as fine-grained multiplexing and high-throughput links. These created considerable challenges for the O.S. designer, since a small protocol data unit size (the 48 byte cell ) and link bandwidths within a (binary) order of magnitude of memory bandwidths demanded considerable rethinking of operating system structure.
Using an historical and personal perspective, this paper describes two aspects of that rethinking which I participated in directly, namely, those of new event signaling and memory buffering schemes. Ideas and techniques stemming from ATM network research influenced first research operating systems and then commercial operating systems. The positive results of ATM networking, although indirect, have benefited applications and systems far beyond the original design goals
A new flexible and modular QoS mapping framework based on psychophysics
Accounting for the perceiving conditions that make up the delivery environment of an application helps improve the efficiency of QoS provisioning systems. It is useless to transmit information whose absence cannot be noticed by the end-user under the actual perceiving conditions. Until now, QoS architectures mostly focused on the transport system and did not integrate the studies achieved in the psychophysics area. In this paper, we propose a QoS framework that accounts for the perceiving conditions. Moreover, our framework is both flexible - i.e., customizable at will by the manager - and modular, with a clear and fine-grained layering. New mechanisms and their supporting characteristics, such as experimental curves, may be very easily introduced and managed in the proposed architecture. A case study is carried out, which shows the applicability of the framework for a video-on-demand provisioning system
Configuration of service oriented architectures with semantic technologies based on non-functional requirements
ΠΠ²Π° Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΡΠ΅ ΡΠΎΠΊΡΡΠΈΡΠ°Π½Π° Π½Π° ΠΏΡΠΈΠΌΠ΅Π½Ρ ΡΠ΅ΠΌΠ°Π½ΡΠΈΡΠΊΠΈΡ
ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ° Π·Π°
ΡΠ΅ΡΠ°Π²Π°ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ° ΠΎΠΏΡΠΈΠΌΠ°Π»Π½Π΅ ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΡΠ΅ ΡΠ΅ΡΠ²ΠΈΡΠ½ΠΎ-ΠΎΡΠΈΡΠ΅Π½ΡΠΈΡΠ°Π½ΠΈΡ
Π°ΡΡ
ΠΈΡΠ΅ΠΊΡΡΡΠ° (Π΅Π½Π³Π». Service Oriented Architecture β SOA) Π½Π° ΠΎΡΠ½ΠΎΠ²Ρ
Π½Π΅ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΈΡ
Π·Π°Ρ
ΡΠ΅Π²Π° ΠΊΠΎΡΠΈΡΠ½ΠΈΠΊΠ°. Π Π΅ΡΠ΅ΡΠ΅ ΡΠ΅ Π±Π°Π·ΠΈΡΠ°Π½ΠΎ Π½Π° ΠΏΡΠΎΡΠΈΡΠ΅ΡΡ ΠHP
Π°Π»Π³ΠΎΡΠΈΡΠΌΠ° Π·Π° ΡΠ°Π΄ ΡΠ° ΡΠ°Π·Π»ΠΈΡΠΈΡΠΈΠΌ Π²ΡΡΡΠ°ΠΌΠ° Π·Π°Ρ
ΡΠ΅Π²Π° ΠΈ ΡΠ°Π·Π²ΠΎΡΡ Ρ
Π΅ΡΡΠΈΡΡΠΈΡΠΊΠΎΠ³ ΠΏΡΠΈΡΡΡΠΏΠ°
Π·Π°ΡΠ½ΠΎΠ²Π°Π½ΠΎΠ³ Π½Π° Π³Π΅Π½Π΅ΡΠΈΡΠΊΠΈΠΌ Π°Π»Π³ΠΎΡΠΈΡΠΌΠΈΠΌΠ° Π·Π° ΡΠ΅ΡΠ°Π²Π°ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ° ΠΎΠΏΡΠΈΠΌΠ°Π»Π½Π΅
ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΡΠ΅. ΠΠΎΡΡΠΎΡΠ΅ΡΠ° ΡΠ΅ΡΠ΅ΡΠ° Ρ ΠΎΠ²ΠΎΡ ΠΎΠ±Π»Π°ΡΡΠΈ ΡΡ ΠΏΠΎΠΊΠ°Π·Π°Π»Π° ΠΈΠ·ΡΠ·Π΅ΡΠ½ΠΎ ΠΌΠ°Π»ΠΈ Π½ΠΈΠ²ΠΎ
ΠΏΠ΅ΡΡΠΎΠ½Π°Π»ΠΈΠ·Π°ΡΠΈΡΠ΅, ΡΡ ΠΊΠΎΡΠΈΡΠ½ΠΈΡΠΈΠΌΠ° Π½ΠΈΡΠ΅ Π΄ΠΎΠ·Π²ΠΎΡΠ΅Π½ΠΎ Π΄Π΅ΡΠΈΠ½ΠΈΡΠ°ΡΠ΅ ΡΠ°Π·Π½ΠΈΡ
ΡΠΎΡΠΈΡΡΠΈΡΠΈΡΠ°Π½ΠΈΡΠΈΡ
Π²ΡΡΡΠ° Π·Π°Ρ
ΡΠ΅Π²Π° ΠΊΠΎΡΠΈ ΠΎΡΠ»ΠΈΠΊΠ°Π²Π°ΡΡ ΡΠΈΡ
ΠΎΠ²Π΅ ΠΆΠ΅ΡΠ΅, ΠΎΡΠ΅ΠΊΠΈΠ²Π°ΡΠ° ΠΈ
ΡΡΡΠΎΠ³Π΅ Π·Π°Ρ
ΡΠ΅Π²Π΅ Π·Π° ΠΊΠΎΡΠ΅ Π·Π°Ρ
ΡΠ΅Π²Π°ΡΡ ΠΏΠΎΡΠΏΡΠ½ΠΎ ΠΈΡΠΏΡΡΠ΅ΡΠ΅. Π’Π°ΠΊΠΎΡΠ΅, ΠΏΠΎΡΡΠΎΡΠ΅ΡΠ° ΡΠ΅ΡΠ΅ΡΠ° ΡΡ
Π±ΠΈΠ»Π° ΠΏΠ΅ΡΠΌΠ°Π½Π΅Π½ΡΠ½ΠΎ ΡΠΎΠΊΡΡΠΈΡΠ°Π½Π° Π½Π° ΠΈΡΠΏΡΡΠ΅ΡΠ΅ Π·Π°Ρ
ΡΠ΅Π²Π° ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΎΡΡΠΈ, Π½Π°ΠΊΠΎΠ½ ΡΠ΅Π³Π°
ΡΠ΅ Π²ΡΡΠΈ ΠΎΠ΄Π°Π±ΠΈΡ ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΡΠ΅ ΡΡ
ΠΎΠ΄Π½ΠΎ Π·Π°Ρ
ΡΠ΅Π²ΠΈΠΌΠ° ΠΎ ΡΠΌΠ°ΡΠ΅ΡΡ Π²ΡΠ΅Π΄Π½ΠΎΡΡΠΈ
ΠΊΠ°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ° ΠΊΠΎΡΠ΅ ΠΈΠΌΠ°ΡΡ ΡΠ΅Π½Π΄Π΅Π½ΡΠΈΡΡ ΡΠ°ΡΡΠ° (Π½ΠΏΡ., ΡΠ΅Π½Π° ΠΈ Π²ΡΠ΅ΠΌΠ΅ ΠΈΠ·Π²ΡΡΠ°Π²Π°ΡΠ°),
ΠΎΠ΄Π½ΠΎΡΠ½ΠΎ ΠΏΠΎΠ²Π΅ΡΠ°ΡΡ Π²ΡΠ΅Π΄Π½ΠΎΡΡΠΈ ΠΊΠ°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ° ΠΊΠΎΡΠ΅ ΠΈΠΌΠ°ΡΡ ΡΠ΅Π½Π΄Π΅Π½ΡΠΈΡΡ ΠΎΠΏΠ°Π΄Π°ΡΠ°
(Π½ΠΏΡ., ΠΏΠΎΡΠ·Π΄Π°Π½ΠΎΡΡ ΠΈ Π΄ΠΎΡΡΡΠΏΠ½ΠΎΡΡ). ΠΠ΅ΡΡΡΠΈΠΌ, ΠΊΠ°Π΄Π° ΡΠ΅ ΠΏΠΎΡΠΌΠ°ΡΡΠ°ΡΡ ΡΠ΅Π»Π΅ ΡΠ°ΠΌΠΈΠ»ΠΈΡΠ΅
SOA, ΠΎΠ΄ ΠΏΠΎΡΠ΅Π±Π½ΠΎΠ³ Π·Π½Π°ΡΠ°ΡΠ° ΠΏΠΎΡΡΠ°ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΡΠ΅ ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΡΠ΅ ΠΏΡΠΈ
ΠΈΡΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½ΠΎΠΌ Π·Π°Π΄ΠΎΠ²ΠΎΡΠ΅ΡΡ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΈΡ
ΠΈ Π½Π΅ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΈΡ
Π·Π°Ρ
ΡΠ΅Π²Π°.
ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ΠΎ ΠΈΠ½ΡΠ΅Π³ΡΠ°Π»Π½ΠΎ ΡΠ΅ΡΠ΅ΡΠ΅ ΠΏΠΎΠ΄ Π½Π°Π·ΠΈΠ²ΠΎΠΌ OptConfSOAFΠΎΠ±Π΅Π·Π±Π΅ΡΡΡΠ΅
ΠΏΡΠ΅Π΄ΡΡΠ°Π²ΡΠ°ΡΠ΅ ΡΠ°Π·Π»ΠΈΡΠΈΡΠΈΡ
Π²ΡΡΡΠ° Π·Π°Ρ
ΡΠ΅Π²Π° (Π±Π΅Π·ΡΡΠ»ΠΎΠ²Π½ΠΈ, ΡΡΠ»ΠΎΠ²Π½ΠΈ, Π·Π°Ρ
ΡΠ΅Π²ΠΈ ΠΎ
Π»Π΅ΠΊΡΠΈΠΊΠΎΠ³ΡΠ°ΡΡΠΊΠΎΠΌ ΠΏΠΎΡΠ΅ΡΠΊΡ) ΠΎ Π½Π΅ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΈΠΌ ΠΊΠ°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠ° ΠΈ ΠΎΠΏΡΠΈΠΌΠ°Π»Π½Ρ
ΠΊΠΎΠ½ΡΠΈΠ³ΡΡΠ°ΡΠΈΡΡ ΡΠ°ΠΌΠΈΠ»ΠΈΡΠ° SOA Π½Π° ΠΎΡΠ½ΠΎΠ²Ρ Π΄Π΅ΡΠΈΠ½ΠΈΡΠ°Π½ΠΈΡ
Π·Π°Ρ
ΡΠ΅Π²Π°. ΠΡΠΈΡΡΡΠΏ ΠΊΠΎΡΠΈ ΡΠ΅
ΠΏΡΠ΅Π΄Π»Π°ΠΆΠ΅ ΠΎΠ±Π΅Π·Π±Π΅ΡΡΡΠ΅ ΠΈΡΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½ΠΎ Π·Π°Π΄ΠΎΠ²ΠΎΡΠ΅ΡΠ΅ Π·Π°Ρ
ΡΠ΅Π²Π° ΠΊΠΎΡΠΈ ΡΠ΅ ΡΠΈΡΡ
ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΎΡΡΠΈ ΡΠΈΡΡΠ΅ΠΌΠ° ΠΊΠ°ΠΎ ΠΈ Π½Π΅ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΈΡ
Π·Π°Ρ
ΡΠ΅Π²Π° ΠΊΠΎΡΠΈ ΠΌΠΎΠ³Ρ Π±ΠΈΡΠΈ
ΡΠ°Π·Π»ΠΈΡΠΈΡΠΎΠ³ Π½ΠΈΠ²ΠΎΠ° ΠΏΡΠΈΠΎΡΠΈΡΠ΅ΡΠ°, ΠΎΠ΄Π½ΠΎΡΠΈΡΠΈ ΡΠ΅ Π½Π° ΠΏΠΎΡΠ΅Π΄ΠΈΠ½Π΅ Π΄Π΅Π»ΠΎΠ²Π΅ ΠΈΠ»ΠΈ ΡΠ΅ΡΠ²ΠΈΡΠ½ΠΎ-
ΠΎΡΠΈΡΠ΅Π½ΡΠΈΡΠ°Π½Ρ Π°ΡΡ
ΠΈΡΠ΅ΠΊΡΡΡΡ Ρ ΡΠ΅Π»ΠΎΡΡΠΈ.
ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ΠΎ ΡΠ΅ΡΠ΅ΡΠ΅ ΡΠ΅ ΠΎΠΏΡΡΠ΅ ΠΈ Π½ΠΈΡΠ΅ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΎ ΡΠ°ΠΌΠΎ Π½Π° Π²Π΅Π± ΡΠ΅ΡΠ²ΠΈΡΠ΅, ΠΈΠ°ΠΊΠΎ
ΡΠ΅ ΠΏΠΎΡΠ°ΠΌ ΡΠ΅ΠΌΠ°Π½ΡΠΈΡΠΊΠΈΡ
ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ° ΠΎΠ±ΠΈΡΠ½ΠΎ Π²Π΅Π·ΡΡΠ΅ Π·Π° Π΄Π°ΡΠΈ Π΄ΠΎΠΌΠ΅Π½ ΠΏΡΠΈΠΌΠ΅Π½Π΅. Π Π΅ΡΠ΅ΡΠ΅
ΡΠ΅ ΠΌΠΎΠΆΠ΅ ΠΏΡΠΈΠΌΠ΅Π½ΠΈΡΠΈ Ρ Π±ΠΈΠ»ΠΎ ΠΊΠΎΠΌ Π΄ΠΎΠΌΠ΅Π½Ρ Ρ ΠΊΠΎΡΠ΅ΠΌ ΡΠ΅ SOA ΠΏΠ°ΡΠ°Π΄ΠΈΠ³ΠΌΠ° ΠΌΠΎΠΆΠ΅
ΠΏΡΠΈΠΌΠ΅Π½ΠΈΡΠΈ ΠΏΠΎΡΠΌΠ°ΡΡΠ°ΡΠ΅ΠΌ ΡΠ΅ΡΠ²ΠΈΡΠ° ΠΊΠ°ΠΎ Π±ΠΈΠ»ΠΎ ΠΊΠΎΡΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠ΅ (Π½Π΅ΠΎΠ±Π°Π²Π΅Π·Π½ΠΎ
ΡΠΎΡΡΠ²Π΅ΡΡΠΊΠ΅) Π΄Π°ΡΠ΅ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»Π½ΠΎΡΡΠΈ...This dissertation is focused on the application of semantic technologies for solving the
problem of optimal configuration of service-oriented architectures (SOA) based on
stakeholdersβ non-functional requirements. The proposed solution is developed as an
extension of the AHP algorithm to allow for processing of different kinds of
requirements. To address the problem of optimal configuration of SOA, a heuristic
approach based on genetic algorithms has also been proposed and validated.
Existing approaches in this field have shown low level of personalization, i.e.
stakeholders are neither enabled to define sophisticated requirements that reflect their
own expectations and attitudes, nor they are able to indicate hard requirements that have
to be fully satisfied. Furthermore, existing approaches were primarily addressing the
problem of fulfilling functional requirements, while the selection of an appropriate
configuration is driven by the goal of decreasing the values of monotonically decreasing
features (e.g., price and execution time) and simultaneous increasing the values of
monotonically increasing features (e.g., availability and reliability). By considering the
whole SOA families, the problem of configuration based on both functional and nonfunctional
requirements gets special importance for research and further applications.
The proposed solution, titled OptConfSOAF provides a framework for
specification and processing of different kinds of requirements (unconditional,
conditional, and requirements about lexicographical order) over non-functional features,
and further optimal configuration of SOA families. The proposed approach provides
simultaneous fulfillment of functional requirements (i.e., requirements related to the
systemβs functionalities) and non-functional requirements, where the latter could be
defined with different level of importance, for specific parts of a SOA-based system or
the system in its entirety.
The proposed solution is general and is not bound to web services, even though
semantic technologies are often associated with that domain. Since the solution
considers a service as a component (no mandatory to be software component) with the
specified functionality, it is applicable and easily adaptable to any specific application
domain where SOA paradigm may be applied..
Quality-oriented adaptation scheme for multimedia streaming in local broadband multi-service IP networks
The research reported in this thesis proposes, designs and tests the Quality-Oriented Adaptation Scheme (QOAS), an application-level adaptive scheme that offers high quality
multimedia services to home residences and business premises via local broadband IP-networks in the presence of other traffic of different types. QOAS uses a novel client-located grading scheme that maps some network-related parametersβ values, variations and variation patterns (e.g. delay, jitter, loss rate) to application-level scores that describe the quality of delivery. This grading scheme
also involves an objective metric that estimates the end-user perceived quality, increasing its effectiveness. A server-located arbiter takes content and rate adaptation decisions based on these quality scores, which is the only information sent via feedback by the clients.
QOAS has been modelled, implemented and tested through simulations and an instantiation of it has been realized in a prototype system. The performance was assessed in terms of estimated end-user perceived quality, network utilisation, loss rate and number of customers served by a fixed infrastructure. The influence of variations in the parameters used by QOAS and of the networkrelated
characteristics was studied. The schemeβs adaptive reaction was tested with background traffic of different type, size and variation patterns and in the presence of concurrent multimedia streaming processes subject to user-interactions. The results show that the performance of QOAS
was very close to that of an ideal adaptive scheme. In comparison with other adaptive schemes QOAS allows for a significant increase in the number of simultaneous users while maintaining a good end-user perceived quality. These results are verified by a set of subjective tests that have been performed on viewers using a prototype system
Design, Implementation and Experiences of the OMEGA End-Point Architecture
The OMEGA architecture provides end-to-end quality of service (QoS) guarantees for distributed applications. QoS parameters are translated between application and network requirements by the QoS Broker, thus integrating media and network QoS management into a single entity. Admission control uses a schedulability test derived from application requirements. A novel task priority and precedence based scheme is used to represent complex application requirements and ensure correct feasible schedules. A prototype of OMEGA has been implemented using workstations connected by a 155 Mbps dedicated ATM LAN. To simplify implementation, we assumed a networked multimedia application with periodic media streams, specifically a master/slave telerobotics application. This application employs media with highly diverse QoS requirements (e.g., interarrival times, loss rate, bandwidth) and therefore provides a good platform for testing how closely one can achieve QoS guarantees with workstation hosts and..