This thesis presents the design and implementation of a transparent messaging protocol for distributed communication between processors. The processors are designed using dataflow architecture. The protocol ensures transparent asynchronous communication between distributed processes. The protocol is designed such that an application can run without change in virtually any kind of distributed configuration, where configuration is the number of controllers used in the system plus the processor allocation strategy used. It also enables an automated processor allocation strategy to transparently configure an application for any number of processor nodes without requiring any changes or recompilation. The protocol works well even for single-controller applications and for a pre-defined allocation of processors to controllers. The thesis further includes an analysis of the time required for one complete cycle of inter-processor communication. / Master of Science

When internet-mediated messaging and social networking applications were introduced in mobile phones, mobile messaging entered a new paradigm. Users can easily create profiles and communicate with other users instantly at anytime of day and anywhere in the world. This paradigm however, has brought forward new privacy issues. Over the course of this exegesis I aimed to explore different aspects of privacy issues related to mobile messaging, including users' awareness and the control of the privacy issues when using social networking messaging. This was demonstrated by conducting a project, which involved development of a mobile phone application and a role-playing game. The project created a frictional scenario of users communicating via mobile messaging. My research revealed that the participants lacked awareness of privacy violations when using mobile messaging, and tended not to modify their behaviours immediately when privacy breaches arose. This research contributes to the existing body of research in the area of mobile messaging privacy, and advocated user awareness of privacy issues in this domain. It could potentially be used as a base for future research.

In the smartphone era, instant messaging is fully embedded in our daily life. Messaging protocols must preserve the confidentiality and authenticity of sent messages both in two-party conversations and in group chats, in which the list of group members may suffer modifications over time. Hence, a precise characterization of their security is required. In this thesis, we analyze the cryptographic properties that are desirable in secure messaging protocols, particularly in asynchronous group key agreement protocols. Our main contribution is a study of the administration of a messaging group, which is a common scenario in which a subset of the group members (the administrators) are the only users allowed to modify the group structure by adding and removing group members. As we discuss, enabling secure group administration mechanisms can enhance the security of messaging protocols. For this purpose, we introduce a new primitive which extends the continuous group key agreement (CGKA) primitive to capture secure administration, which we denote by administrated CGKA (A-CGKA). The definition is followed by a correctness notion and an informal security description. We present two constructions of our A-CGKA that can be built on top of any CGKA: individual admin signatures (IAS), and dynamic group signature (DGS), both constructed using signature schemes. Furthermore, we provide a detailed overview of secure group messaging in which we discuss group evolution, efficiency, concurrency, and different adversarial models. We introduce a novel CGKA correctness definition (in the so-called propose-and-commit paradigm), followed by a security game that incorporates the correctness properties. We also survey some variants of the TreeKEM protocol and compare their security. / I de smarta telefonernas tid är direktmeddelanden en självklar del av vår vardag. Meddelandeprotokoll måste upprätthålla konfidentialitet och autenticitet för skickade meddelanden både i tvåpartskonversationer samt i gruppchatter vars medlemslistor kan förändras över tid. Därför krävs en precis karaktärisering av deras säkerhet. I detta arbete analyserar vi de kryptografiska egenskaper som är önskvärda i meddelandeprotokoll med fokus på asynkrona gruppnyckelavtalsprotokoll (group key agreement protocols). Arbetets huvudsakliga bidrag till området är en studie av administrationen av en meddelandegrupp. Detta är ett vanligt förekommande scenario där endast en delmängd av gruppmedlemmarna (administratörerna) tillåts modifiera gruppens struktur genom att lägga till och ta bort medlemmar. Som diskuteras i arbetet kan användandet av säkra gruppadministrationsmekanismer (group administration mechanisms) förbättra säkerheten för meddelandeprotokoll. I detta syfte introducerar vi en ny kryptografisk primitiv vilken uttökar den s.k. “continuous group key agreement”-primitiven (CGKA) till att även innefatta säker administration. Denna primitiv kallar vi administrated CGKA (A-CGKA), vars definition följs av en korrekthetsdefinition och en informell säkerhetsbeskrivning. Vi presenterar två konstruktioner av A-CGKA som kan byggas ovanpå vilken CGKA som helst: individual admin signatures (IAS) och dynamic group signature (DGS), som båda konstrueras via signaturscheman. Utöver detta ger vi även en detaljerad överblick över säkra gruppmeddelanden i vilken vi diskuterar gruppevolution, effektivitet, samtidighet och olika fientliga modeller. Vi introducerar en ny definition av korrekthet för CGKA (vilket följer paradigmen propose-and-commit) följt av ett s.k. “security game” som inkorporerar korrekthetsegenskaperna. Vi undersöker även varianter av TreeKEM-protokollet och jämför deras säkerhet.

Text communication is often perceived as lacking some components of communication that are essential in sustaining interaction or conversation. This interaction incoherency tends to make text communication plastic. It is traditionally devoid of intonation, pitch, gesture, facial expression and visual or auditory cues. Nevertheless, Instant Messaging (IM), a form of text communication is on the upward uptake both on PCs and on mobile handhelds. There is a need to rubberise this plastic text messaging to improve co-presence for text communications thereby improving synchronous textual discussion, especially on handheld devices. <br /> <br /> One element of interaction is gesture, seen as a natural way of conversing. Attaining some level of interaction naturalism requires improving synchronous communication spontaneity, partly achieved by enhancing input mechanisms. To enhance input mechanisms for interactive text-based chat on mobile devices, there is a need to facilitate gesture input. Enhancement is achievable in a number of ways, such as input mechanism redesigning and input offering adaptation. This thesis explores affective gesture mode on interface redesign as an input offering adaptation. This is done without a major physical reconstruction of handheld devices.<br /> <br /> This thesis presents a text only IM system built on Session Initiation Protocol (SIP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE). It was developed with a novel user-defined hotkey implemented as a one-click context menu to &ldquo / fast-track&rdquo / text-gestures and emoticons.<br /> <br /> A hybrid quantitative and qualitative approach was taken to enable data triangulation. Results from experimental trials show that an Affective Gesture (AG) approach improved IM chat spontaneity/response. Feedback from the user trials affirms that AG hotkey improves chat responsiveness, thus enhancing chat spontaneity.

En años recientes, el uso de tabletas y teléfonos o dispositivos inteligentes ha incrementado continuamente gracias a la facilidad y disponibilidad de acceso a la información, entretenimiento y comunicación que ofrecen con su creciente variedad de aplicativos y especialmente su acceso a internet. A diferencia de computadoras o notebooks, estos dispositivos tienen tecnologías para mejorar la usabilidad para personas con dificultades visuales que también pueden ser utilizadas para crear nuevos aplicativos de asistencia sin la necesidad de aparatos externos. Esto genera oportunidades para un desarrollo inclusivo que mantiene la misma portabilidad. Sin embargo, estos dispositivos principalmente usan una pantalla táctil y aún entre sus tecnologías incorporadas, no tienen medios para ingresar datos que sean permitan que personas con ceguera ingresen información por otros medios que no sean su voz o un complejo teclado QWERTY. En este artículo, proponemos el uso de una solución adaptativa que permite al usuario usar la misma pantalla táctil como una alternativa para ingresar datos al simular un teclado Braille y demostramos su uso, además de tecnologías de lector de texto, con una aplicación que permite que una persona ciega chatee mediante mensajes instantáneos.

Inter-cloud is a recently emerging approach that expands cloud elasticity. By facilitating an adaptable setting, it purposes at the realization of a scalable resource provisioning that enables a diversity of cloud user requirements to be handled efficiently. This study’s contribution is in the inter-cloud performance optimization of job executions using metascheduling concepts. This includes the development of the inter-cloud meta-scheduling (ICMS) framework, the ICMS optimal schemes and the SimIC toolkit. The ICMS model is an architectural strategy for managing and scheduling user services in virtualized dynamically inter-linked clouds. This is achieved by the development of a model that includes a set of algorithms, namely the Service-Request, Service-Distribution, Service-Availability and Service-Allocation algorithms. These along with resource management optimal schemes offer the novel functionalities of the ICMS where the message exchanging implements the job distributions method, the VM deployment offers the VM management features and the local resource management system details the management of the local cloud schedulers. The generated system offers great flexibility by facilitating a lightweight resource management methodology while at the same time handling the heterogeneity of different clouds through advanced service level agreement coordination. Experimental results are productive as the proposed ICMS model achieves enhancement of the performance of service distribution for a variety of criteria such as service execution times, makespan, turnaround times, utilization levels and energy consumption rates for various inter-cloud entities, e.g. users, hosts and VMs. For example, ICMS optimizes the performance of a non-meta-brokering inter-cloud by 3%, while ICMS with full optimal schemes achieves 9% optimization for the same configurations. The whole experimental platform is implemented into the inter-cloud Simulation toolkit (SimIC) developed by the author, which is a discrete event simulation framework.

A maneira como percebemos visualmente o entorno afeta nosso próprio conhecimento do mesmo como um conceito de realidade. Este olhar, no entanto, não é influenciado apenas pelas peculiaridades físicas da visão humana ou por um conceito de subjetividade de um único indivíduo; ele é resultante de um determinado contexto social, cultural e tecnológico. Paralelamente são estes os fatores condicionantes que moldam a linguagem--verbal e visual--de um coletivo. Estas linguagens, por sua vez, delimitam aquilo que sabemos ou percebemos do mundo, pois são codificações que transformam os fênomenos e manifestações em conceitos transmissíveis por seus respectivos mecanismos de sintaxe. Entende-se que toda forma de linguagem criada pelo ser humano é um exercício de analogia da fenomenologia do cosmos. / The way we visually perceive the environment affects our own concept of reality. Sigh, however, is not only influenced by physical peculiarities of human\'s vision neither by one\'s concept of subjectivity; It is the result of a particular social, cultural and technological context. At the same time, these are the conditioning aspects that gives shape to a collectivity\'s verbal and visual language. These forms of languages delimit what we know or perceive about the world because they are codefying processes that transform phenomenons and manifestations themselves into concepts capable of being transmited one to another by their respective mechanisms of syntax. It is understood that every form of language created by humans is an analogy of the cosmos\' phenomenology.

What formal guarantees should a secure messaging application provide? Do the most widely-used protocols provide them? Can we do better? In this thesis we answer these questions and with them give a formal study of modern secure messaging protocols, which encrypt the personal messages of billions of users. We give definitions and analyses of two protocols: one existing (Signal) and one new (ART). For Signal, we begin by extending and generalising classic computational models, in order to apply them to its complex ratcheting key derivations. With a threat model in mind we also define a security property, capturing strong secrecy and authentication guarantees including a new one which we call "post-compromise security". We instantiate Signal as a protocol in our model, stating its security theorem and sketching a computational reduction. Signal only supports encrypting messages between two devices, and so most implementers have built custom protocols on top of it to support group conversations. These protocols usually provide weaker security guarantees, and in particular usually do not have post-compromise security. We propose a new protocol called ART, whose goal is to bring Signal's strong security properties to conversations with multiple users and devices. We give a design rationale and a precise definition of ART, and again generalise existing computational models in order to formally specify its security properties and sketch a security reduction. ART has enjoyed widespread interest from industry, and we aim to turn it into an open standard for secure messaging. To that end, we have brought it to the IETF and formed a working group called Messaging Layer Security, with representatives from academia as well as Facebook, Google, Twitter, Wire, Cisco and more. Through MLS, we hope to bring ART's strong guarantees to practical implementations across industry. After concluding our analyses we pause for a moment, and start looking towards the future. We argue that for complex protocols like Signal and ART we are reaching the limits of computational methods, and that the future for their analysis lies with symbolic verification tools. To that end we return to the symbolic model and give a number of case studies, in each one showing how a traditional limitation of symbolic models can in fact be seen as a modelling artefact.

This paper traces an unfolding process of applying principles of organizational storytelling to build an unpublished website. I created this website to tell the story of a small nonprofit seeking to increase and continue its watershed restoration efforts. Storytelling has become a popular messaging approach within non-profit organizations. I conducted direct interviews with key members of the organization, then set selected excerpts within the context of a written meta-story that conveys information, delivers a call to action, and provides a means for visitor response. Site content corresponds to categories of narrative discourse designed to encourage active response from listeners. The site design employs techniques for capturing and maintaining visitor interaction. The paper includes theoretical discussion of organizational storytelling, non-profit messaging, and website building, as well as basic ideas for future launch and utilization of the website and additional applications of the audio recording files.

Mobile banking is an application of mobile computing which provides customers with the support needed to be able to bank anywhere, anytime using a mobile handheld device and a mobile service such as text messaging (SMS). Mobile banking removes space and time limitations from banking activities such as checking account balances, or transferring money from one account to another. In recent research and studies it was found that while mobile banking and more specifically SMS-based mobile banking applications have become popular in some countries and regions, they were still not widely used. This study identifies and investigates the factors which influence customers’ decision to use a specific form of mobile banking, and specifically focuses on the evaluation of SMS-based mobile banking in the context of New Zealand. The research model includes the basic concepts of the Technology Acceptance Model (TAM), as well as some constructs derived through a focus group discussion. The model is tested to determine its predictive power with respect to individual’s behaviour when considering the use of SMS-based mobile banking. A survey questionnaire was developed and employed to collect data from 250 AUT university students in New Zealand. The results of the data analysis contributes to the body of knowledge in the area by demonstrating that context specific factors such as service quality and service awareness are influencing user perceptions about the usefulness of SMS mobile banking which in turn affect intention to use and adoption. Secondly, the study demonstrates, on the example of SMS-based mobile banking, how a hybrid approach involving qualitative data collection and a subsequent quantitative survey can help investigate how user perceptions about usefulness and ease of use are formed. Although the study has its limitations, the implications of the results allow providing practical recommendations to the banking industry, and directions for further work.