Book•
Power Management in Mobile Devices
21 Dec 2007-
TL;DR: This book describes various design approaches to reduce the amount of power a circuit consumes and techniques to effectively manage the available power.
Abstract: Sealed Lead Acid.Nickel Cadmium.Lithium Ion.How do you balance battery life with performance and cost?This book shows you how!Now that "mobile" has become the standard, the consumer not only expects mobility but demands power longevity in wireless devices. As more and more features, computing power, and memory are packed into mobile devices such as iPods, cell phones, and cameras, there is a large and growing gap between what devices can do and the amount of energy engineers can deliver. In fact, the main limiting factor in many portable designs is not hardware or software, but instead how much power can be delivered to the device. This book describes various design approaches to reduce the amount of power a circuit consumes and techniques to effectively manage the available power.Power Management Advice On:.Low Power Packaging Techniques.Power and Clock Gating.Energy Efficient Compilers.Various Display Technologies.Linear vs. Switched Regulators.Software Techniques and Intelligent Algorithms * Addresses power versus performance that each newly developed mobile device faces* Robust case studies drawn from the author's 30 plus years of extensive real world experience are included* Both hardware and software are discussed concerning their roles in power
Citations
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15 May 2011
TL;DR: In this survey, the energy consuming entities of a mobile device such as wireless air interfaces, display, mp3 player and others are measured and compared and allow the reader to understand what the energy hungry parts of aMobile device are and use those findings for the design of future mobile protocols and applications.
Abstract: The full degree of freedom in mobile systems heavily depends on the energy provided by the mobile phone's batteries. Their capacity is in general limited and for sure not keeping pace as the mobile devices are crammed up with new functionalities. The discrepancy of Moore's law, offering twice the processing power at least each second year, and the development in batteries, which did not even double over the last decade, makes a shift in researchers' way of designing networks, protocols, and the mobile device itself. The bottleneck to take care of in the design process of mobile systems is not only the wireless data rate, but even more the energy limitation as the customers ask for new energy-hungry services, e.g., requiring faster connections or even multiple air interfaces, and longer standby or operational times of their mobile devices at the same time. In this survey, the energy consuming entities of a mobile device such as wireless air interfaces, display, mp3 player and others are measured and compared. The presented measurement results allow the reader to understand what the energy hungry parts of a mobile device are and use those findings for the design of future mobile protocols and applications. All results presented in this work and further results are made public on our web page [2].
337 citations
DOI•
01 Jan 2018
TL;DR: This work presents the CLKSCREW attack, a new class of fault attacks that exploit the securityobliviousness of energy management mechanisms to break security and urges the community to re-examine these security-oblivious designs.
158 citations
Proceedings Article•
01 Jan 2017TL;DR: In this paper, the authors present the CLKSCREW attack, a new class of fault attacks that exploit the security obliviousness of energy management mechanisms to break security and demonstrate that a malicious kernel driver can extract secret cryptographic keys from Trustzone, and escalate its privileges by loading self-signed code into Trustzone.
Abstract: The need for powerand energy-efficient computing has resulted in aggressive cooperative hardware-software energy management mechanisms on modern commodity devices. Most systems today, for example, allow software to control the frequency and voltage of the underlying hardware at a very fine granularity to extend battery life. Despite their benefits, these software-exposed energy management mechanisms pose grave security implications that have not been studied before. In this work, we present the CLKSCREW attack, a new class of fault attacks that exploit the securityobliviousness of energy management mechanisms to break security. A novel benefit for the attackers is that these fault attacks become more accessible since they can now be conducted without the need for physical access to the devices or fault injection equipment. We demonstrate CLKSCREW on commodity ARM/Android devices. We show that a malicious kernel driver (1) can extract secret cryptographic keys from Trustzone, and (2) can escalate its privileges by loading self-signed code into Trustzone. As the first work to show the security ramifications of energy management mechanisms, we urge the community to re-examine these security-oblivious designs.
138 citations
TL;DR: A design technique for colors with the purpose of lowering the energy consumption of the display device is presented, based on a screen space variant energy model, and the result is a set of distinguishable iso‐lightness colors guided by perceptual principles.
Abstract: We present a design technique for colors with the purpose of lowering the energy consumption of the display device. Our approach is based on a screen space variant energy model. The result of our design is a set of distinguishable iso-lightness colors guided by perceptual principles. We present two variations of our approach. One is based on a set of discrete user-named (categorical) colors, which are analyzed according to their energy consumption. The second is based on the constrained continuous optimization of color energy in the perceptually uniform CIELAB color space. We quantitatively compare our two approaches with a traditional choice of colors, demonstrating that we typically save approximately 40 percent of the energy. The color sets are applied to examples from the 2D visualization of nominal data and volume rendering of 3D scalar fields.
46 citations
18 Aug 2014
TL;DR: Experimental results indicate that this smart human motion and network management scheme increases the survival rate and also prolongs the energy life time of smart phones for future usage as unexpected contingencies develop.
Abstract: Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN)-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF) and a cognitive packet network (CPN)-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN)-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.
40 citations
Cites background from "Power Management in Mobile Devices"
...However, due to the limitation on battery size and the efficiency of chemical reactions of the widely-used lithium-ion batteries [52], the capacity of batteries becomes a bottleneck in the operational time of the cloud-based system....
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