cISP: A Speed-of-Light Internet Service Provider

Low latency is a requirement for a variety of interactive network applications. The Internet, however, is not optimized for latency. We thus explore the design of cost-effective wide-area networks that move data over paths very close to great-circle paths, at speeds very close to the speed of light in vacuum. Our cISP design augments the Internet's fiber with free-space wireless connectivity. cISP addresses the fundamental challenge of simultaneously providing low latency and scalable bandwidth, while accounting for numerous practical factors ranging from transmission tower availability to packet queuing. We show that instantiations of cISP across the contiguous United States and Europe would achieve mean latencies within 5% of that achievable using great-circle paths at the speed of light, over medium and long distances. Further, we estimate that the economic value from such networks would substantially exceed their expense

The Formal Semantics of Core ABS and ABS-NET

ABS is a language and framework for modelling distributed object-oriented systems, developed in the EU FP7 HATS project. Core ABS formalizes the key parts of ABS, including the syntax, type system, and an operational semantics in the style of rewriting logic. ABS-NET is a novel operational semantics for Core ABS programs, developed as a part of work on decentralized runtime adaptation of distributed objects. ABS-NET describes program execution on top of a network of nodes connected point-to-point with asynchronous message passing links. This report describes the syntax and semantics of Core ABS and ABS-NET, and is meant to serve as a reference, while highlighting the differences between the reference semantics of ABS programs and the ABS-NET semantics

Extending the Communication Capabilities of Agents

Agent technology is in principle well suited for realizing various kinds of distributed systems, but in practice agents are seldomly chosen for realizing real-world applications. One reason hindering agents being used in practice is their cumbersome communication mechanism focused on speech act based message exchange which makes them hard for practitioners used to work in an object oriented way. To broaden the application spectrum of agent technology in practice and make them more accessible for object-oriented developers, this paper presents additional communication means for agents. First, it will be shown how agents can interact using strongly typed service interfaces resorting to asynchronous future based methods. These allow keeping agents autonomous and further support several recurrent interaction patterns within one method call, i.e. without having to use complex message protocols. Second, an extension for binary data streaming via virtual connections will be presented. Its usage resembles established input and output streaming APIs and lets developers transfer data between agents in the same simple way as e.g. a file is written to hard disk. Furthermore, virtual connections allow failure tolerant transmission by multiplexing data across different physical connections. Usefulness of the extensions will be further explained with a real-word example application from the area of business intelligence workflows

An Emergent Architecture for Scaling Decentralized Communication Systems (DCS)

With recent technological advancements now accelerating the mobile and wireless Internet solution space, a ubiquitous computing Internet is well within the research and industrial community's design reach - a decentralized system design, which is not solely driven by static physical models and sound engineering principals, but more dynamically, perhaps sub-optimally at initial deployment and socially-influenced in its evolution. To complement today's Internet system, this thesis proposes a Decentralized Communication System (DCS) architecture with the following characteristics: flat physical topologies with numerous compute oriented and communication intensive nodes in the network with many of these nodes operating in multiple functional roles; self-organizing virtual structures formed through alternative mobility scenarios and capable of serving ad hoc networking formations; emergent operations and control with limited dependency on centralized control and management administration. Today, decentralized systems are not commercially scalable or viable for broad adoption in the same way we have to come to rely on the Internet or telephony systems. The premise in this thesis is that DCS can reach high levels of resilience, usefulness, scale that the industry has come to experience with traditional centralized systems by exploiting the following properties: (i.) network density and topological diversity; (ii.) self-organization and emergent attributes; (iii.) cooperative and dynamic infrastructure; and (iv.) node role diversity. This thesis delivers key contributions towards advancing the current state of the art in decentralized systems. First, we present the vision and a conceptual framework for DCS. Second, the thesis demonstrates that such a framework and concept architecture is feasible by prototyping a DCS platform that exhibits the above properties or minimally, demonstrates that these properties are feasible through prototyped network services. Third, this work expands on an alternative approach to network clustering using hierarchical virtual clusters (HVC) to facilitate self-organizing network structures. With increasing network complexity, decentralized systems can generally lead to unreliable and irregular service quality, especially given unpredictable node mobility and traffic dynamics. The HVC framework is an architectural strategy to address organizational disorder associated with traditional decentralized systems. The proposed HVC architecture along with the associated promotional methodology organizes distributed control and management services by leveraging alternative organizational models (e.g., peer-to-peer (P2P), centralized or tiered) in hierarchical and virtual fashion. Through simulation and analytical modeling, we demonstrate HVC efficiencies in DCS structural scalability and resilience by comparing static and dynamic HVC node configurations against traditional physical configurations based on P2P, centralized or tiered structures. Next, an emergent management architecture for DCS exploiting HVC for self-organization, introduces emergence as an operational approach to scaling DCS services for state management and policy control. In this thesis, emergence scales in hierarchical fashion using virtual clustering to create multiple tiers of local and global separation for aggregation, distribution and network control. Emergence is an architectural objective, which HVC introduces into the proposed self-management design for scaling and stability purposes. Since HVC expands the clustering model hierarchically and virtually, a clusterhead (CH) node, positioned as a proxy for a specific cluster or grouped DCS nodes, can also operate in a micro-capacity as a peer member of an organized cluster in a higher tier. As the HVC promotional process continues through the hierarchy, each tier of the hierarchy exhibits emergent behavior. With HVC as the self-organizing structural framework, a multi-tiered, emergent architecture enables the decentralized management strategy to improve scaling objectives that traditionally challenge decentralized systems. The HVC organizational concept and the emergence properties align with and the view of the human brain's neocortex layering structure of sensory storage, prediction and intelligence. It is the position in this thesis, that for DCS to scale and maintain broad stability, network control and management must strive towards an emergent or natural approach. While today's models for network control and management have proven to lack scalability and responsiveness based on pure centralized models, it is unlikely that singular organizational models can withstand the operational complexities associated with DCS. In this work, we integrate emergence and learning-based methods in a cooperative computing manner towards realizing DCS self-management. However, unlike many existing work in these areas which break down with increased network complexity and dynamics, the proposed HVC framework is utilized to offset these issues through effective separation, aggregation and asynchronous processing of both distributed state and policy. Using modeling techniques, we demonstrate that such architecture is feasible and can improve the operational robustness of DCS. The modeling emphasis focuses on demonstrating the operational advantages of an HVC-based organizational strategy for emergent management services (i.e., reachability, availability or performance). By integrating the two approaches, the DCS architecture forms a scalable system to address the challenges associated with traditional decentralized systems. The hypothesis is that the emergent management system architecture will improve the operational scaling properties of DCS-based applications and services. Additionally, we demonstrate structural flexibility of HVC as an underlying service infrastructure to build and deploy DCS applications and layered services. The modeling results demonstrate that an HVC-based emergent management and control system operationally outperforms traditional structural organizational models. In summary, this thesis brings together the above contributions towards delivering a scalable, decentralized system for Internet mobile computing and communications

A framework for the design, prototyping and evaluation of mobile interfaces for domestic environments

The idea of the smart home has been discussed for over three decades, but it has yet to achieve mass-market adoption. This thesis asks the question Why is my home not smart? It highlights four main areas that are barriers to adoption, and concentrates on a single one of these issues: usability. It presents an investigation that focuses on design, prototyping and evaluation of mobile interfaces for domestic environments resulting in the development of a novel framework. A smart home is the physical realisation of a ubiquitous computing system for domestic living. The research area offers numerous benefits to end-users such as convenience, assistive living, energy saving and improved security and safety. However, these benefits have yet to become accessible due to a lack of usable smart home control interfaces. This issue is considered a key reason for lack of adoption and is the focus for this thesis. Within this thesis, a framework is introduced as a novel approach for the design, prototyping and evaluation of mobile interfaces for domestic environments. Included within this framework are three components. Firstly, the Reconfigurable Multimedia Environment (RME), a physical evaluation and observation space for conducting user centred research. Secondly, Simulated Interactive Devices (SID), a video-based development and control tool for simulating interactive devices commonly found within a smart home. Thirdly, iProto, a tool that facilitates the production and rapid deployment of high fidelity prototypes for mobile touch screen devices. This framework is evaluated as a round-tripping toolchain for prototyping smart home control and found to be an efficient process for facilitating the design and evaluation of such interfaces

Statistical learning in network architecture

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 167-[177]).The Internet has become a ubiquitous substrate for communication in all parts of society. However, many original assumptions underlying its design are changing. Amid problems of scale, complexity, trust and security, the modern Internet accommodates increasingly critical services. Operators face a security arms race while balancing policy constraints, network demands and commercial relationships. This thesis espouses learning to embrace the Internet's inherent complexity, address diverse problems and provide a component of the network's continued evolution. Malicious nodes, cooperative competition and lack of instrumentation on the Internet imply an environment with partial information. Learning is thus an attractive and principled means to ensure generality and reconcile noisy, missing or conflicting data. We use learning to capitalize on under-utilized information and infer behavior more reliably, and on faster time-scales, than humans with only local perspective. Yet the intrinsic dynamic and distributed nature of networks presents interesting challenges to learning. In pursuit of viable solutions to several real-world Internet performance and security problems, we apply statistical learning methods as well as develop new, network-specific algorithms as a step toward overcoming these challenges. Throughout, we reconcile including intelligence at different points in the network with the end-to-end arguments. We first consider learning as an end-node optimization for efficient peer-to-peer overlay neighbor selection and agent-centric latency prediction. We then turn to security and use learning to exploit fundamental weaknesses in malicious traffic streams. Our method is both adaptable and not easily subvertible. Next, we show that certain security and optimization problems require collaboration, global scope and broad views.(cont.) We employ ensembles of weak classifiers within the network core to mitigate IP source address forgery attacks, thereby removing incentive and coordination issues surrounding existing practice. Finally, we argue for learning within the routing plane as a means to directly optimize and balance provider and user objectives. This thesis thus serves first to validate the potential for using learning methods to address several distinct problems on the Internet and second to illuminate design principles in building such intelligent systems in network architecture.by Robert Edward Beverly, IV.Ph.D

Transforming big data into knowledge : experimental techniques in dynamic visualization

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 122-124).Information visualizations, especially those utilizing web-based platforms, are becoming an increasingly common medium for exchanging ideas. This emergent class of tools enabling web-based, interactive platforms for visualizing data should be considered by urban planners and designers as an opportunity to create new modes of disseminating and communicating information. This thesis provides an overview of new visualization tools: how they are being developed and combined, their applications, and their potential future uses. It also explores the implications of such tools in contexts where technology is not yet mainstream. This is illustrated through a case study of using mobile phones to gather data on the bus system in Dhaka, Bangladesh. The research draws from literature written on critical cartography, visualization, and visual culture in urban design and planning. The work first develops a best practices workflow of existing and emerging visualization tools and platforms. It then constructs prototypes of products for various audiences that illustrate the outputs of data collected on Dhaka's bus system, showcasing the potentials of these new tools and platforms.by Stephen James Kennedy.M.C.P

Distributed resource discovery: architectures and applications in mobile networks

As the amount of digital information and services increases, it becomes increasingly important to be able to locate the desired content. The purpose of a resource discovery system is to allow available resources (information or services) to be located using a user-defined search criterion. This work studies distributed resource discovery systems that guarantee all existing resources to be found and allow a wide range of complex queries. Our goal is to allocate the load uniformly between the participating nodes, or alternatively to concentrate the load in the nodes with the highest available capacity. The first part of the work examines the performance of various existing unstructured architectures and proposes new architectures that provide features especially valuable in mobile networks. To reduce the network traffic, we use indexing, which is particularly useful in scenarios, where searches are frequent compared to resource modifications. The ratio between the search and update frequencies determines the optimal level of indexing. Based on this observation, we develop an architecture that adjusts itself to changing network conditions and search behavior while maintaining optimal indexing. We also propose an architecture based on large-scale indexing that we later apply to resource sharing within a user group. Furthermore, we propose an architecture that relieves the topology constraints of the Parallel Index Clustering architecture. The performance of the architectures is evaluated using simulation. In the second part of the work we apply the architectures to two types of mobile networks: cellular networks and ad hoc networks. In the cellular network, we first consider scenarios where multiple commercial operators provide a resource sharing service, and then a scenario where the users share resources without operator support. We evaluate the feasibility of the mobile peer-to-peer concept using user opinion surveys and technical performance studies. Based on user input we develop access control and group management algorithms for peer-to-peer networks. The technical evaluation is performed using prototype implementations. In particular, we examine whether the Session Initiation Protocol can be used for signaling in peer-to-peer networks. Finally, we study resource discovery in an ad hoc network. We observe that in an ad hoc network consisting of consumer devices, the capacity and mobility among nodes vary widely. We utilize this property in order to allocate the load to the high-capacity nodes, which serve lower-capacity nodes. We propose two methods for constructing a virtual backbone connecting the nodes

Behavioural semantics for asynchronous components

International audienceSoftware components are a valuable programming abstraction that enables a compositional design of complex applications. In distributed systems, components can also be used to provide an abstraction of locations: each component is a unit of deployment that can be placed on a different machine. In this article, we consider this kind of distributed components that are additionally loosely coupled and communicate by asynchronous invocations. Components also provide a convenient abstraction for verifying the correct behaviour of systems: they provide structuring entities easing the correctness verification. This article provides a formal background for the generation of behavioural semantics for asynchronous components. It expresses the semantics of hierarchical distributed components communicating asynchronously by requests, futures, and replies; this semantics is provided using the pNet intermediate language. This article both demonstrates the expressiveness of the pNet model and formally specifies the complete process of the generation of a behavioural model for a distributed component system. The purpose of our be-havioural semantics is to allow for verification both by finite instantiation and model-checking, and by techniques for infinite systems

NASA/NBS (National Aeronautics and Space Administration/National Bureau of Standards) standard reference model for telerobot control system architecture (NASREM)

The document describes the NASA Standard Reference Model (NASREM) Architecture for the Space Station Telerobot Control System. It defines the functional requirements and high level specifications of the control system for the NASA space Station document for the functional specification, and a guideline for the development of the control system architecture, of the 10C Flight Telerobot Servicer. The NASREM telerobot control system architecture defines a set of standard modules and interfaces which facilitates software design, development, validation, and test, and make possible the integration of telerobotics software from a wide variety of sources. Standard interfaces also provide the software hooks necessary to incrementally upgrade future Flight Telerobot Systems as new capabilities develop in computer science, robotics, and autonomous system control