The global mobile application market is booming in all directions and business giants, viz. Google and Apple, have acknowledged the huge expansion in their Application Market and App Store. There is a demand though for a system that can elevate the momentum of context-aware mobile applications, where an application’s behavior is customized according to context information. This thesis proposes a context-aware system that provides mobile Applications as a Service (AppaaS). AppaaS handles various context information including location information, user profile, device profile, user ratings, and current time to provision the best relevant mobile application to such a context. AppaaS also supports state preservation, where application-specific data that is relevant to a user is stored for future reference. Our prototype demonstrates a seamless system performance with respect to finding relevant applications to a specific context and controlling the applications functions according the users requirements and access privileges. We also demonstrate how AppaaS can preserve an applications state when a user is to reuse the same application again. / Thesis (Master, Computing) -- Queen's University, 2013-01-31 20:23:11.063

As semiconductor technology scales down, process variations become increasingly difficult to control. To cope with this, more and more conservative delay and clock frequency estimations are used during design, which result in overly large and leaky circuits. Also, the system runs at a speed slower than that possible because a fixed clock determined by the worst-case analysis of the circuit is used. On top of process variations, voltage and temperature variations also push the designer towards even more conservative delay estimations. On the other hand, asynchronous design style has potential advantages over synchronous design including resilience to process variations, lower power consumption and higher performance. Unfortunately, these advantages are usually hindered by the significant design effort required to implement useful asynchronous circuits and also by the overhead of asynchronous control logic. Borrowing from asynchronous techniques, a new methodology is proposed to design synchronous circuits that have some of the advantages of asynchronous circuits. Asynchronous logic is used to generate the clock of a synchronous system. The resulting system automatically tunes itself to deliver the best-possible performance under the prevailing process-voltage-temperature (PVT) conditions. This methodology may be used to reduce the leakage power significantly in deep nanometer technologies. It also helps in handling process variations. The results from a 32-bit processor implemented in 90nm technology shows 10X leakage reduction compared to the traditional synchronous design. The proposed technique is expanded to adjust the speed of a pipeline according to the current operations flowing in the pipeline as well as the current PVT conditions. The results from a 32-bit processor in 90nm technology demonstrate a 2X speed improvement compared to the conventional synchronous design. The proposed techniques only use synchronous design tools and are compatible with design flows that are currently in use.

As semiconductor technology scales down, process variations become increasingly difficult to control. To cope with this, more and more conservative delay and clock frequency estimations are used during design, which result in overly large and leaky circuits. Also, the system runs at a speed slower than that possible because a fixed clock determined by the worst-case analysis of the circuit is used. On top of process variations, voltage and temperature variations also push the designer towards even more conservative delay estimations. On the other hand, asynchronous design style has potential advantages over synchronous design including resilience to process variations, lower power consumption and higher performance. Unfortunately, these advantages are usually hindered by the significant design effort required to implement useful asynchronous circuits and also by the overhead of asynchronous control logic. Borrowing from asynchronous techniques, a new methodology is proposed to design synchronous circuits that have some of the advantages of asynchronous circuits. Asynchronous logic is used to generate the clock of a synchronous system. The resulting system automatically tunes itself to deliver the best-possible performance under the prevailing process-voltage-temperature (PVT) conditions. This methodology may be used to reduce the leakage power significantly in deep nanometer technologies. It also helps in handling process variations. The results from a 32-bit processor implemented in 90nm technology shows 10X leakage reduction compared to the traditional synchronous design. The proposed technique is expanded to adjust the speed of a pipeline according to the current operations flowing in the pipeline as well as the current PVT conditions. The results from a 32-bit processor in 90nm technology demonstrate a 2X speed improvement compared to the conventional synchronous design. The proposed techniques only use synchronous design tools and are compatible with design flows that are currently in use.

Submitted by Marcio Filho (marcio.kleber@ufba.br) on 2017-06-06T13:37:20Z No. of bitstreams: 1 dissertacao_marcelo_mendonca.pdf: 29068279 bytes, checksum: 80fb8fb6ea4e3852373e2a42c4467ea6 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-06-16T15:11:16Z (GMT) No. of bitstreams: 1 dissertacao_marcelo_mendonca.pdf: 29068279 bytes, checksum: 80fb8fb6ea4e3852373e2a42c4467ea6 (MD5) / Made available in DSpace on 2017-06-16T15:11:16Z (GMT). No. of bitstreams: 1 dissertacao_marcelo_mendonca.pdf: 29068279 bytes, checksum: 80fb8fb6ea4e3852373e2a42c4467ea6 (MD5) / Correctly identifying the road area on an image is a crucial task for many traffic analyses based on surveillance cameras and computer vision. Despite that, most of the systems do not provide this functionality in an automatic fashion; instead, the road area needs to be annotated by tedious and inefficient manual processes. This situation results in further inconveniences when one deals with a lot of cameras, demanding considerable effort to setup the system. Besides, since traffic analysis is an outdoor activity, cameras are exposed to disturbances due to natural events (e.g., wind, rain and bird strikes), which may require recurrent system reconfiguration. Although there are some solutions intended to provide automatic road detection, they are not capable of dealing with common situations in urban context, such as poorly-structured roads or occlusions due to objects stopped in the scene. Moreover in many cases they are restricted to straight-shaped roads (commonly freeways or highways), so that automatic road detection cannot be provided in most of the traffic scenarios. In order to cope with this problem, we propose a new approach for road detection. Our method is based on a set of innovative solutions, each of them intended to address specific problems related to the detection task. In this sense, a context-aware background modeling method has been developed, which extracts contextual information from the scene in order to produce background models more robust to occlusions. From this point, segmentation is performed to extract the shape of each object in the image; this is accomplished by means of a superpixel method specially designed for road segmentation, which allows for detection of roads with any shape. For each extracted segment we then compute a set of features, the goal of which is supporting a decision tree-based classifier in the task of assigning the objects as being road or non-road. The formulation of our method — a road detection carried out by a combination of multiple features — makes it able to deal with situations where the road is not easily distinguishable from other objects in the image, as when the road is poorly-structured. A thorough evaluation has indicated promising results in favour of this method. Quantitatively, the results point to 75% of accuracy, 90% of precision and 82% of recall over challenging traffic videos caught in non-controlled conditions. Qualitatively, resulting images demonstrate the potential of the method to perform road detection in different situations, in many cases obtaining quasi-perfect results.

Modern vehicles have an increasing number of advanced features requiring network coverage in order to function properly. In order to facilitate the requirements of such features and allow more advanced applications, we consider the possibility of planning routes that take signal strength into consideration. Previous work have shown the relationship between TCP throughput/goodput and signal strength. In this thesis signal-aware route planning is presented, implemented, and validated. Crowd-sourced map and signal data (3G) from two sources is used for building a signal coverage map. The signal and map data is validated in a field experiment, where routes were travelled while measuring the signal strength. The field experiment showed gains in signal characteristics when deviating from the shortest possible path. The average signal strength increased by 11 dBm between algorithms and the shortest possible path. Lastly, routes were planned for all possible sources and destinations in a given urban area. The results of this calculation confirms the patterns found in the field experiment.

<p>As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including   AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network.</p> / MediaSense

As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including   AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network. / MediaSense

Over the past few decades, we have been enjoying tremendous benefits thanks to the revolutionary advancement of computing systems, driven mainly by the remarkable semiconductor technology scaling and the increasingly complicated processor architecture. However, the exponentially increased transistor density has directly led to exponentially increased power consumption and dramatically elevated system temperature, which not only adversely impacts the system's cost, performance and reliability, but also increases the leakage and thus the overall power consumption. Today, the power and thermal issues have posed enormous challenges and threaten to slow down the continuous evolvement of computer technology. Effective power/thermal-aware design techniques are urgently demanded, at all design abstraction levels, from the circuit-level, the logic-level, to the architectural-level and the system-level. In this dissertation, we present our research efforts to employ real-time scheduling techniques to solve the resource-constrained power/thermal-aware, design-optimization problems. In our research, we developed a set of simple yet accurate system-level models to capture the processor's thermal dynamic as well as the interdependency of leakage power consumption, temperature, and supply voltage. Based on these models, we investigated the fundamental principles in power/thermal-aware scheduling, and developed real-time scheduling techniques targeting at a variety of design objectives, including peak temperature minimization, overall energy reduction, and performance maximization. The novelty of this work is that we integrate the cutting-edge research on power and thermal at the circuit and architectural-level into a set of accurate yet simplified system-level models, and are able to conduct system-level analysis and design based on these models. The theoretical study in this work serves as a solid foundation for the guidance of the power/thermal-aware scheduling algorithms development in practical computing systems.

This study explores the subject of providing personalized services to mobile users, by exploiting relevant domain knowledge (i.e. contextual information). Although the process of gathering, modelling and processing of context has been extensively researched, there are only a few studies in the literature showing how such context can be effectively utilized to provide services valuable to the general public. Instead, there exist a multitude of examples of services targeted towards specialized audiences, either because the scope of each service is not of broad interest, or because of custom software and/or hardware requirements. Part of the reason why the scope of such services is so narrow can also be attributed to short service life cycle. While all such services offer relative value to interested audiences, we support that contemporary mainstream mobile devices are now more than ever capable of running large-scale context-aware applications as the required combination of hardware and software is available. This licentiate thesis challenges the current state-of-the art in context aware services by proposing an alternative perspective, driven from the appreciation of the user rather than from the ideas of a system designer. The potential impact of this work lies in the set of diverse applications which have been implemented using existing mainstream technology, targeting large and diverse sets of audiences. In order to realize the vision, we have implemented a context-aware system featuring a flexible architecture that is able to scale to the requirements of different services. In order to demonstrate the flexibility of this architecture as well as to prove the aforementioned claims, we have implemented support for two context aware services which have demonstratively had a large appeal to users. These scenarios not only include full implementation and exposure to public use, but they also differ from each other in terms of their functionality: A printing service where the printing resources are scattered within a workspace environment. The system selects the most appropriate printer for a mobile user to print his or her document on, based on the user's location and nature of the document relative to the capabilities of each of the printers. A recommender system service where mobile users are forwarded Web feeds of related interest, based on each user's social signature on the web (i.e. social context). The reader should note the tangible nature of context used in the services above, as context is not only associated - by tradition - with knowledge relative to physical stimuli (e.g. location), but is also related to information present on contemporary media such as the World Wide Web. / QC 20110516

Master of Philosophy (Architecture) / Context-aware computing is a mobile computing paradigm in which applications can discover, use, and take advantage of contextual information, such as the location, tasks and preferences of the user, in order to adapt their behaviour in response to changing operating environments and user requirements. A problem that arises is the inability to respond to contextual information that cannot be classified into any known context. Many context-aware applications require all discovered contextual information to exactly match a type of context, otherwise the application will not react responsively. The ability to learn and recall contexts based on the contextual information discovered has not been very well addressed by previous context-aware applications and research. The aim of this thesis is to develop a component middleware technology for mobile computing devices for the discovery and capture of contextual information, using the situated reasoning concept of constructive memory. The research contribution of this thesis lies in developing a modified architecture for context-aware systems, using a constructive memory model as a way to learn and recall contexts from previous experiences and application interactions. Using a constructive memory model, previous experiences can be induced to construct potential contexts, given a small amount of learning and interaction. The learning process is able to map the many variations of contextual information currently discovered by the user with a predicted type of context based on what the application has stored and seen previously. It only requires a small amount of contextual information to predict a context, something common context-aware systems lack, as they require all information before a type of context is assigned. Additionally, some mechanism to reason about the contextual information being discovered from past application interactions will be beneficial to induce contexts for future experiences.