The Design of a System Architecture for Mobile Multimedia Computers

This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies

VANET Applications: Hot Use Cases

Current challenges of car manufacturers are to make roads safe, to achieve free flowing traffic with few congestions, and to reduce pollution by an effective fuel use. To reach these goals, many improvements are performed in-car, but more and more approaches rely on connected cars with communication capabilities between cars, with an infrastructure, or with IoT devices. Monitoring and coordinating vehicles allow then to compute intelligent ways of transportation. Connected cars have introduced a new way of thinking cars - not only as a mean for a driver to go from A to B, but as smart cars - a user extension like the smartphone today. In this report, we introduce concepts and specific vocabulary in order to classify current innovations or ideas on the emerging topic of smart car. We present a graphical categorization showing this evolution in function of the societal evolution. Different perspectives are adopted: a vehicle-centric view, a vehicle-network view, and a user-centric view; described by simple and complex use-cases and illustrated by a list of emerging and current projects from the academic and industrial worlds. We identified an empty space in innovation between the user and his car: paradoxically even if they are both in interaction, they are separated through different application uses. Future challenge is to interlace social concerns of the user within an intelligent and efficient driving

Synergy: An Energy Monitoring and Visualization System

The key to becoming a more sustainable society is first learning to take responsibility for the role we play in energy consumption. Real-time energy usage gives energy consumers a sense of responsibility over what they can do to accomplish a much larger goal for the planet, and practically speaking, what they can do to lower the cost to their wallets. Synergy is an energy monitoring and visualization system that enables users to gather information about the energy consumption in a building – small or large – and display that data for the user in real-time. The gathered energy usage data is processed on the edge before being stored in the cloud. The two main benefits of edge processing are issuing electricity hazard warnings immediately and preserving user privacy. In addition to being a scalable solution that intended for use in individual households, commercial offices and city power grids, Synergy is open-source so that it can be implemented more widely. This paper contains a system overview as well as initial finding based on the data collected by Synergy before assessing the impact the system can have on society

Lessons learned from the design of a mobile multimedia system in the Moby Dick project

Recent advances in wireless networking technology and the exponential development of semiconductor technology have engendered a new paradigm of computing, called personal mobile computing or ubiquitous computing. This offers a vision of the future with a much richer and more exciting set of architecture research challenges than extrapolations of the current desktop architectures. In particular, these devices will have limited battery resources, will handle diverse data types, and will operate in environments that are insecure, dynamic and which vary significantly in time and location. The research performed in the MOBY DICK project is about designing such a mobile multimedia system. This paper discusses the approach made in the MOBY DICK project to solve some of these problems, discusses its contributions, and accesses what was learned from the project

Anticipatory Mobile Computing: A Survey of the State of the Art and Research Challenges

Today's mobile phones are far from mere communication devices they were ten years ago. Equipped with sophisticated sensors and advanced computing hardware, phones can be used to infer users' location, activity, social setting and more. As devices become increasingly intelligent, their capabilities evolve beyond inferring context to predicting it, and then reasoning and acting upon the predicted context. This article provides an overview of the current state of the art in mobile sensing and context prediction paving the way for full-fledged anticipatory mobile computing. We present a survey of phenomena that mobile phones can infer and predict, and offer a description of machine learning techniques used for such predictions. We then discuss proactive decision making and decision delivery via the user-device feedback loop. Finally, we discuss the challenges and opportunities of anticipatory mobile computing.Comment: 29 pages, 5 figure

User-Centric Power Management For Mobile Operating Systems

The power consumption of mobile devices must be carefully managed to provide a satisfied battery life to users. This target, however, recently has become more and more difficult to complete. We still cannot expect the battery life problem be solved economically shortly, even though researchers already addressed many aspects of this problem. Principally, that\u27s because existing power management systems, which concentrate on controlling hardware power states, cannot effectively make these hardware components work in low-power mode. Why is this the case? Based on our analysis of 14 users\u27 device usage trace, we found that background applications generate too many activities when the device is either idle or active. These activities are either unimportant or unnecessary for the user. However, a significant amount of CPU time was consumed by them. Moreover, these application activities cause many system services to consume a considerable quantity of battery energy. When we install more applications on our mobile devices, this situation will become even worse. Most application developers rarely consider the power consumption of applications. How to control application state and eliminate redundant application activities become more and more important. Existing power management systems, apparently, cannot handle this situation. Some publications already tried to solve the problem several years ago. For example, EcoSystem and Cinder operating systems try to allocate battery energy precisely to applications based on their requirements. However, the problem with their solution is that the estimated application power consumption cannot accurately represent its reasonable demand. Energy-aware adaptation is another solution to decrease application power consumption. In our previous research, we implemented the {\em Anole} framework to supply energy adaptation APIs to applications. To use this framework, application developers have to implement power-saving strategies in their program. In the operating system, we need to change application behavior automatically in energy adaptation mode. We noticed the latest iOS operating system implemented the idea; the system notifies users to turn off background application update when the battery level is lower than $20\%$. However, this kind of uniformity in power management can hardly be accepted by most users, because user habits are different from each other. We need to customize the power management strategy for each user. Otherwise, the user experience may be significantly impacted. To solve this problem, we propose user-centric power management, which utilizes the usage pattern of the individual user to distinguish important application from regular applications. Energy-saving strategies will not influence important applications to the user. From the analysis of 14 users\u27 device usage traces, we found that most users\u27 user behavior follows their pattern, which is both time-dependent and location-dependent. Based on this observation, we propose the UPS power management, which collects user behaviors and analyzes the usage pattern of users. We can easily use it to bridge usage behavior to energy-saving strategies. We also proposed three energy-saving strategies, UCASS, LocalLite and WakeFilter, to optimize the redundancy in background application activities and location service usage, and the abuse of in wakelock usage. Our simulation result based on real device usage traces shows that these three strategies can effectively save battery energy consumed background application activities, location requests, and wakelock requests