A Multimodal Instant Messaging System using XML-Based Protocols

Instant Messaging is traditionally a text only affair. However, there are instances when it would be useful to bridge to other types of media, like speech. The SoftBridge is an application framework that enables this kind of communications bridging using instant messages. Its use of protocols like the Jabber Instant Messaging Protocol and the Simple Object Access Protocol makes it simple, open and extensible. It also allows bridging to non IP communications infrastructure, like the telephone network. We describe the design and architecture of the system, protocol and extensibility mechanism. Finally we describe our experimental methodology and discuss the results of two sets of experiments: those involving a Deaf User, and those involving a set of Simulated Users

SoftBridge: A Multimodal Instant Messaging Bridging System

Instant Messaging is traditionally a text only affair. However, there are instances when it would be useful to bridge to other types of media, like speech. The SoftBridge is an application framework that enables this kind of communications bridging using instant messages. Its use of protocols like the Jabber Instant Messaging Protocol and the Simple Object Access Protocol makes it simple, open and extensible. It also allows bridging to non IP communications infrastructure, like the telephone network. We describe the design and architecture of the system, protocol and extensibility mechanism. Finally we describe our experimental methodology and discuss the results of our initial experiments

Dealing with Receiver Misbehavior in Multicast Congestion Control

In multicast congestion control, receivers can misbehave by maliciously causing congestion to steal network bandwidth from well behaved flows. In source driven congestion control protocols (SDCC), receivers misbehave by sending a wrong feedback to the source. In receiver-driven congestion control protocols(RDCC), receivers misbehave by inflating their subscriptions. In this report, we present techniques to deal with these misbehaviours. Firstly, we show that when network tomography tools such as MINC are used in conjunction with SDCC protocols, they can aid in misbehavior detection. But in order to use MINC for misbehaviour detection, MINC itself must be made immune to misbehaviour. we analyze the effect of misbehavior within MINC and propose two techniques to detect and prevent misbehavior in MINC. For RDCC protocols, a misbehaviour prevention mechanism based on in-band distribution of keys was recently proposed for FLID-DL protocol. In this report, we show how we can design keys which can prevent misbehaviour in most RDCC protocols

Cross-layer latency-aware and -predictable data communication

Cyber-physical systems are making their way into more aspects of everyday life. These systems are increasingly distributed and hence require networked communication to coordinatively fulfil control tasks. Providing this in a robust and resilient manner demands for latency-awareness and -predictability at all layers of the communication and computation stack. This thesis addresses how these two latency-related properties can be implemented at the transport layer to serve control applications in ways that traditional approaches such as TCP or RTP cannot. Thereto, the Predictably Reliable Real-time Transport (PRRT) protocol is presented, including its unique features (e.g. partially reliable, ordered, in-time delivery, and latency-avoiding congestion control) and unconventional APIs. This protocol has been intensively evaluated using the X-Lap toolkit that has been specifically developed to support protocol designers in improving latency, timing, and energy characteristics of protocols in a cross-layer, intra-host fashion. PRRT effectively circumvents latency-inducing bufferbloat using X-Pace, an implementation of the cross-layer pacing approach presented in this thesis. This is shown using experimental evaluations on real Internet paths. Apart from PRRT, this thesis presents means to make TCP-based transport aware of individual link latencies and increases the predictability of the end-to-end delays using Transparent Transmission Segmentation.Cyber-physikalische Systeme werden immer relevanter für viele Aspekte des Alltages. Sie sind zunehmend verteilt und benötigen daher Netzwerktechnik zur koordinierten Erfüllung von Regelungsaufgaben. Um dies auf eine robuste und zuverlässige Art zu tun, ist Latenz-Bewusstsein und -Prädizierbarkeit auf allen Ebenen der Informations- und Kommunikationstechnik nötig. Diese Dissertation beschäftigt sich mit der Implementierung dieser zwei Latenz-Eigenschaften auf der Transport-Schicht, sodass Regelungsanwendungen deutlich besser unterstützt werden als es traditionelle Ansätze, wie TCP oder RTP, können. Hierzu wird das PRRT-Protokoll vorgestellt, inklusive seiner besonderen Eigenschaften (z.B. partiell zuverlässige, geordnete, rechtzeitige Auslieferung sowie Latenz-vermeidende Staukontrolle) und unkonventioneller API. Das Protokoll wird mit Hilfe von X-Lap evaluiert, welches speziell dafür entwickelt wurde Protokoll-Designer dabei zu unterstützen die Latenz-, Timing- und Energie-Eigenschaften von Protokollen zu verbessern. PRRT vermeidet Latenz-verursachenden Bufferbloat mit Hilfe von X-Pace, einer Cross-Layer Pacing Implementierung, die in dieser Arbeit präsentiert und mit Experimenten auf realen Internet-Pfaden evaluiert wird. Neben PRRT behandelt diese Arbeit transparente Übertragungssegmentierung, welche dazu dient dem TCP-basierten Transport individuelle Link-Latenzen bewusst zu machen und so die Vorhersagbarkeit der Ende-zu-Ende Latenz zu erhöhen

Service design : imperatives, processes and communication

This research was an investigation into the nature of new service design (NSD) activity. The thesis researched literature on NSD and established limits of its applicability. Also developed was NSD process and content theory outside such limits. The research was a multiple site case study. At the level of case-sites the study used the interpretative approach called "explanation-building; " the development of narratives that explained data using concepts from the literature review. The "crosscase" analysis tested these theoretical concepts and allowed the emergence of new empirical categories, and the development of new theoretical categories and hypotheses. Imperatives and stimuli for NSD were a mix of environmental pressure and pressure to deploy resources. Demand-side pressure for variety and the propensity of the resource-base to continually enhance capability mean that service organisations are inevitably exposed to resource or market risk. The organisational response should respect the nature and extent of risk exposure; internal 'imbalances' between resource capability and market needs must be redressed in the NSD response. The applicability of "stage-gate" models of NSD is limited to those contexts where the service is analogous to a manufactured good. In addition there are six other contexts with corresponding process ideals. Unless the outcome of the NSD process is holistic, implementation problems are the result. Holistic NSDs include a strategic rationale, the proposed market offering, process implications and structural or infrastructural resource implications. The initial configuration of NSD communication devices is dependent on the nature of the NSD process. If NSD is focussed on resource / process development then the vernacular of NSD tends to be resource / process descriptions. If NSD addresses exposure to market risk, then NSD constructs tend to be marketing devices. Thus during the NSD process the NSD need not be holistic, by the end of the process it should be

When Complex is as Simple as it Gets: Guide for Recasting Policy and Management in the Anthropocene

Many readers recognise and understand that complex is about as simple as it gets for major policy and management. This guide is for those unwilling in the Anthropocene to shrink back into the older platitudes about ‘keep it simple’ and ‘not to worry, we’ll scale up the analysis later on’. This guide offers key concepts, methods, counternarratives, and analogies that recast major policy and management issues in ways that do not deny their complexity but help render them more tractable for action.European Research Council, Grant No. 74032US National Science Foundation Grant No. 212152

The rhythm of life is a powerful beat: demand response opportunities for time-shifting domestic electricity practices

The 2008 Climate Change Act set legally-binding carbon reduction targets. Demand side management (DSM) includes energy use reduction and peak shaving and offers significant potential to reduce the amount of carbon used by the electricity grid. The demand side management (DSM) schemes that have tried to meet this challenge have been dominated by engineering-based approaches and so favour tools like automation (which aims to make shifting invisible) and pricing (which requires customer response) to shift demand. These approaches tend to focus on the tools for change and take little account of people and energy-use practices. This thesis argues that these approaches are limited and therefore unlikely to produce the level of response that will be needed in future. The thesis therefore investigates the potential for time-shifting domestic energy demand but takes a different angle by trying to understand how people use energy in their daily lives, whether this use can be shifted and some of the implications of shifting it. The centrepiece of the work is an empirical study of eleven households energy-use practices. The interdisciplinary methodology involved in-house observations, interviews, photographs, metered energy data and disruptive interventions. The data was collected in two phases. Initially, a twenty-four hour observation was carried out in each household to find out how energy was implicated in everyday practices. Next, a series of three challenges were carried out, aimed at assessing the implications of disrupting practices by time-shifting food preparation, laundry and work/ leisure. A practice theory approach is used to shift the focus of attention from appliances, tools for change, behaviour or even people, to practices. The central finding of this work is that practices were flexible. This finding is nuanced, in the light of the empirical research, by an extended discussion on the nature of practices; in particular, the relationship between practices and agency and the temporal-spatial locatedness of practices. The findings demonstrate that, in this study at least, expanding the range of demand response options was possible. The research suggests numerous possibilities for extending the potential of practices to shift in time and space, shift the energy used in practices or substitute practices for other non-energy-using practices, though there are no simple technological or behavioural fixes . More profoundly, however, the thesis concludes that infrastructures of provision , such as the electricity grid and the companies that run it, underpin and facilitate energy-use practices irrespective of the time of day and year. In this context technology-led demand response schemes may ultimately contribute to the problem they purport to solve. A more fundamental interrogation of demand and the infrastructures that serve it is therefore necessary and is almost entirely absent from the demand response debate

Successful illicit opium production suppression interventions: a comparative analysis of China, Iran, Turkey, Thailand, Pakistan, Viet Nam and Laos

This study departs from existing scholarship by analysing and documenting nine cases of national ‘success’ to inform three primary objectives: (1) To catalogue cases of success for future reference; (2) To producing ‘lessons’ that may improve the effectiveness of interventions whilst reducing inadvertent negative outcomes; (3) To reconcile the discrepancy between national and international effects of interventions at the source.A comparison of the nine cases of national success found: (1) All governments perceived suppression as in its best interest; (2) All possessed authority throughout opium producing areas; (3) In all but two cases the state offered incentives from which farmers perceived some benefit to the cessation of opium production; (4) All governments possessed the capability to monitor opium farmers; (5) All interventions administered law enforcement. As these five factors presented across all or most cases they can be considered necessary for a successful outcome. Additional factors, which crossed more than one case, were deemed facilitative of the five necessary factors, and included: development-orientated approaches; community punishments; negotiated eradication; and conflict resolution/limitation. The findings suggest that the primary objective when planning a national intervention must be the establishment or maintenance of the five necessary factors. As such, premature eradication - which often deviates from the establishment/maintenance of the five necessary factors - represents an erroneous path, which can be costly in terms of time and resources. The case of Afghanistan is used to further clarify and explore the cross-case findings in a practical context.</div