Supporting distributed computation over wide area gigabit networks

The advent of high bandwidth fibre optic links that may be used over very large distances has lead to much research and development in the field of wide area gigabit networking. One problem that needs to be addressed is how loosely coupled distributed systems may be built over these links, allowing many computers worldwide to take part in complex calculations in order to solve "Grand Challenge" problems. The research conducted as part of this PhD has looked at the practicality of implementing a communication mechanism proposed by Craig Partridge called Late-binding Remote Procedure Calls (LbRPC). LbRPC is intended to export both code and data over the network to remote machines for evaluation, as opposed to traditional RPC mechanisms that only send parameters to pre-existing remote procedures. The ability to send code as well as data means that LbRPC requests can overcome one of the biggest problems in Wide Area Distributed Computer Systems (WADCS): the fixed latency due to the speed of light. As machines get faster, the fixed multi-millisecond round trip delay equates to ever increasing numbers of CPU cycles. For a WADCS to be efficient, programs should minimise the number of network transits they incur. By allowing the application programmer to export arbitrary code to the remote machine, this may be achieved. This research has looked at the feasibility of supporting secure exportation of arbitrary code and data in heterogeneous, loosely coupled, distributed computing environments. It has investigated techniques for making placement decisions for the code in cases where there are a large number of widely dispersed remote servers that could be used. The latter has resulted in the development of a novel prototype LbRPC using multicast IP for implicit placement and a sequenced, multi-packet saturation multicast transport protocol. These prototypes show that it is possible to export code and data to multiple remote hosts, thereby removing the need to perform complex and error prone explicit process placement decisions

Computer Science's Digest Volume 1

This series is dedicated to the students of the Systems Department, to give them reading material related to computer science in a second language. This book covers the Introduction to Computer Science, Computer Communications, Networking and Web Applications

A distributed intelligent network based on CORBA and SCTP

The telecommunications services marketplace is undergoing radical change due to the rapid convergence and evolution of telecommunications and computing technologies. Traditionally telecommunications service providers’ ability to deliver network services has been through Intelligent Network (IN) platforms. The IN may be characterised as envisioning centralised processing of distributed service requests from a limited number of quasi-proprietary nodes with inflexible connections to the network management system and third party networks. The nodes are inter-linked by the operator’s highly reliable but expensive SS.7 network. To leverage this technology as the core of new multi-media services several key technical challenges must be overcome. These include: integration of the IN with new technologies for service delivery, enhanced integration with network management services, enabling third party service providers and reducing operating costs by using more general-purpose computing and networking equipment. In this thesis we present a general architecture that defines the framework and techniques required to realise an open, flexible, middleware (CORBA)-based distributed intelligent network (DIN). This extensible architecture naturally encapsulates the full range of traditional service network technologies, for example IN (fixed network), GSM-MAP and CAMEL. Fundamental to this architecture are mechanisms for inter-working with the existing IN infrastructure, to enable gradual migration within a domain and inter-working between IN and DIN domains. The DIN architecture compliments current research on third party service provision, service management and integration Internet-based servers. Given the dependence of such a distributed service platform on the transport network that links computational nodes, this thesis also includes a detailed study of the emergent IP-based telecommunications transport protocol of choice, Stream Control Transmission Protocol (SCTP). In order to comply with the rigorous performance constraints of this domain, prototyping, simulation and analytic modelling of the DIN based on SCTP have been carried out. This includes the first detailed analysis of the operation of SCTP congestion controls under a variety of network conditions leading to a number of suggested improvements in the operation of the protocol. Finally we describe a new analytic framework for dimensioning networks with competing multi-homed SCTP flows in a DIN. This framework can be used for any multi-homed SCTP network e.g. one transporting SIP or HTTP

Advances in integrating autonomy with acoustic communications for intelligent networks of marine robots

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2013Autonomous marine vehicles are increasingly used in clusters for an array of oceanographic tasks. The effectiveness of this collaboration is often limited by communications: throughput, latency, and ease of reconfiguration. This thesis argues that improved communication on intelligent marine robotic agents can be gained from acting on knowledge gained by improved awareness of the physical acoustic link and higher network layers by the AUV’s decision making software. This thesis presents a modular acoustic networking framework, realized through a C++ library called goby-acomms, to provide collaborating underwater vehicles with an efficient short-range single-hop network. goby-acomms is comprised of four components that provide: 1) losslessly compressed encoding of short messages; 2) a set of message queues that dynamically prioritize messages based both on overall importance and time sensitivity; 3) Time Division Multiple Access (TDMA) Medium Access Control (MAC) with automatic discovery; and 4) an abstract acoustic modem driver. Building on this networking framework, two approaches that use the vehicle’s “intelligence” to improve communications are presented. The first is a “non-disruptive” approach which is a novel technique for using state observers in conjunction with an entropy source encoder to enable highly compressed telemetry of autonomous underwater vehicle (AUV) position vectors. This system was analyzed on experimental data and implemented on a fielded vehicle. Using an adaptive probability distribution in combination with either of two state observer models, greater than 90% compression, relative to a 32-bit integer baseline, was achieved. The second approach is “disruptive,” as it changes the vehicle’s course to effect an improvement in the communications channel. A hybrid data- and model-based autonomous environmental adaptation framework is presented which allows autonomous underwater vehicles (AUVs) with acoustic sensors to follow a path which optimizes their ability to maintain connectivity with an acoustic contact for optimal sensing or communication.I wish to acknowledge the sponsors of this research for their generous support of my tuition, stipend, and research: the WHOI/MIT Joint Program, the MIT Presidential Fellowship, the Office of Naval Research (ONR) # N00014-08-1-0011, # N00014-08-1-0013, and the ONR PlusNet Program Graduate Fellowship, the Defense Advanced Research Projects Agency (DARPA) (Deep Sea Operations: Applied Physical Sciences (APS) Award # APS 11-15 3352-006, APS 11-15-3352-215 ST 2.6 and 2.7

PyPWA: A Software Toolkit for Parameter Optimization and Amplitude Analysis

PyPWA is a toolkit designed to optimize parametric models describing data and generate simulated distributions according to a model. Its software has been written within the python ecosystem with the goal of performing Amplitude or Partial Wave Analysis (PWA) in nuclear and particle physics experiments. We briefly describe the general features of amplitude analysis and the PyPWA software design and usage. We provide benchmarks of the scaling and an example of its application

Підсистема інтелектуального редактора природномовних текстів

Структура та обсяг дипломної роботи. Магістерська дисертація складається зі вступу, чотирьох розділів, висновку, переліку посилань з 30 найменувань, 1 додатку, і містить 20 рисунків, 31 таблицю. Повний обсяг магістерської дисертації складає 82 сторінки, з яких перелік посилань займає 3 сторінки, додатки – 3 сторінки. Актуальність теми. Проблема асистування створенню природномовних текстів здебільшого зводиться лише до перевірки — орфографії та синтаксису, а підказки рідко виходять за межі доповнення префіксу до леми чи найчастотнішої словоформи, саме тому тема роботи є актуальною, вихідний продукт роботи підвищить ефективність та якість написання природномовних текстів. Зв’язок роботи з науковими програмами, планами, темами. Робота відноситься до наукової програми «Методи та засоби підвищення ефективності природномовних програмних систем». Мета дослідження — побудова підсистеми інтелектуального редактора природномовних текстів та створення мовного сервера. Для досягнення поставленої задачі були сформульовані наступні завдання дослідження, що визначили логіку дослідження та його структуру: розглянути особливості природномовних текстів та інструментальне забезпечення для їх використання, розробити та реалізувати архітектуру розширюваного середовища для написання природномовних текстів, розробити архітектуру мовного сервера для написання природномовних текстів. Об’єкт дослідження — підсистема інтелектуального редактора природномовних текстів. Предмет дослідження — підсистема інтелектуального редактора природномовних текстів на основі Visual Studio Code. 4 Наукова новизна одержаних результатів. В процесі виконання роботи набуло подальшого розвитку надання мовної підтримки для написання текстів природною мовою за рахунок: створення синтаксичних аналізаторів з врахуванням афіксів, удосконалення провайдерів розумного доповнення, створення мовного сервера, удосконалення протоколу мовного сервера. Створення синтаксичних аналізаторів з врахуванням афіксів забезпечує більш точне обчислення релевантності лексеми шляхом врахування контексту. Удосконалення провайдерів розумного доповнення забезпечує зменшення витраченого часу при написанні групи лексем. Створення виділеного мовного сервера забезпечує зменшення навантаження на мовний клієнт, можливості оновлення мовних провайдерів без необхідності оновлення мовного клієнта та покращило швидкість надання мовної підтримки. Протокол мовного сервера удосконалено за рахунок обрання протоколу більш низького рівняв якості транспортного, це забезпечує зменшення обсягу повідомлення.Structure and scope of the thesis. The master's thesis consists of an introduction, four sections, conclusion, a list of references of 30 titles, 1 appendix, and contains 20 figures, 31 tables. The full volume of the master's thesis is 82 pages, of which the list of links occupies 3 pages, the appendices - 3 pages. Actuality of theme. The problem of assisting with the creation of natural-language texts is mostly confined to spelling and syntax, and clues rarely go beyond adding a prefix to a lemma or the most frequent word-form, which is why the topic of work is relevant, the original product of the work will increase the efficiency and quality of writing natural-language texts. Relationship with working with scientific programs, plans, topics. The work is related to the scientific program "Methods and Means of Improving the Efficiency of Natural-Language Software Systems". The purpose of the study is to build a subsystem of intelligent editor of natural language texts and to create a language server. To achieve this task, the following research objectives were formulated, which defined the logic of the study and its structure: to consider the features of natural-language texts and tools for their use, to develop and implement an architecture of extensible environment for writing natural-language texts, to develop a language server architecture for writing natural-language texts. The object of study is the subsystem of intelligent editor of natural-language texts. The subject of the research is the subsystem of intelligent editor of natural-language texts on the basis of Visual Studio Code. Scientific novelty of the obtained results. In the course of the work, the development of language support for writing texts in natural language was further developed through the creation of affix parser, perfection of smart supplement providers, creation of the language server, and improvement of the language server protocol. Creating affixed parsers provides more accurate computation of the token's relevance by context. Improving Reasonable Provisioning Providers reduces the time spent writing a token group. Creating a dedicated language server reduces the load on the language client, upgrades the language providers without the need to update the language client, and improves the speed of language support. The language server protocol has been improved by choosing a lower level protocol as the transport protocol, which reduces the volume of the message