Papers by Alessandro Bogliolo
Integrated Computer-aided Engineering, Apr 1, 1998
Behavioral power estimation is required to help the designer in making important architectural ch... more Behavioral power estimation is required to help the designer in making important architectural choices. In this work we propose an accurate and general behavioral power modeling approach especially suited for synthesis-based design ows making use of a library of hard macros implementing behavioral operators. Power dissipation models are pre-characterized and back-annotated in a preliminary step. Accurate information on the power dissipation of the used macros can then be collected during behavioral simulation of the synthesized circuit. Our characterization and modeling methodology is based on the theory of linear regression. Optimal linear power models are obtained with methods of least squares tting and their generalization to a recursive procedure called tree r egression. The regression models can be used for pattern-based dynamic power simulation and for probabilistic static power estimation as well. Our behavioral simulator is integrated within PPP, a m ultilevel simulation engine for power estimation fully compatible with Verilog XL.
European Design and Test Conference, Mar 17, 1997
In this work we propose an eective solution to the main challenges of behavioral power modeling: ... more In this work we propose an eective solution to the main challenges of behavioral power modeling: the generation of models for the power dissipation of technology-independent soft macros and the strong dependence o f p ower from input pattern statistics. Our methodology is based on a fast characterization performed by simulating the gate-level implementation of instances of soft macros within the behavioral description of the complete design. Once characterization has been completed, the backannotated b ehavioral model replaces the gate-level representation, thus allowing fast but accurate power estimates in a fully behavioral context. Our power characterization procedure is a very ecient process that can be e asily embedded in synthesisbased design ows. No additional eort is required f r om the designer, since p ower characterization merges seamlessly with a natural top-down design methodology with iterative improvement. After characterization, the behavioral power simulation produces accurate average and instantaneous power estimates (with errors around 7% and 25%, respectively, from accurate gate-level power simulation).
Springer eBooks, 1999
Dynamic power management is a design methodology aiming at controlling performance and power leve... more Dynamic power management is a design methodology aiming at controlling performance and power levels of digital circuits and systems, with the goal of extending the autonomous operation time of battery-powered systems, providing graceful performance degradation when supply energy is limited, and adapting power dissipation to satisfy environmental constraints. We survey system-level dynamic power management techniques. We first analyze idleness detection and shutdown mechanisms for idle hardware resources and we review industrial standards for operating system-based power management. We describe system-level stochastic models for the power/performance behavior of systems. We analyze different modeling assumptions and we discuss their validity and generality. Last, we describe methods for determining optimum power management strategies and also describe various validation methods that can be employed to assess the effectiveness of power-manageable architectures and the associated power-management schemes.
Power consumption is an increasingly important constraint for complex ICs. Accurate and e cient p... more Power consumption is an increasingly important constraint for complex ICs. Accurate and e cient p o w er estimations are required at any level of abstraction to steer the design process. PPP is a Web-based integrated environment for synthesis and simulation of low-power CMOS circuits. We describe the simulation engine of PPP and we propose a new paradigm for tool integration. The simulation engine of PPP is a gate-level simulator that achieves accuracy comparable with electrical simulation, while keeping performance competitive with traditional gate-level techniques. This is done by using advanced symbolic models of the basic library cells, that exploit the understanding of the main phenomena involved in power consumption. In order to maintain full compatibility with gate-level design tools, we use VERILOG-XL as simulation platform. The accuracy obtained on benchmark circuits is always within 6 from SPICE also for single-gate single-pattern power analysis, thus providing the local information needed to optimize the design. Interface and tool integration issues have been addressed using a Web-based approach. The graphical interface of PPP is a dynamically generated tree of interactive HTML pages that allow the user to access and execute the tool through the Internet by using his her own Web-browser. No software installation is required and all the details of data transfer and tool communication are hidden to the user.
Proceedings Design, Automation and Test in Europe, Nov 27, 2002
We propose a new approach to RT-level power modeling for combinational macros, that does not requ... more We propose a new approach to RT-level power modeling for combinational macros, that does not require simulationbased characterization. A p attern-dependent power model for a macro is analytically constructed using only structural information about its gate-level implementation. The approach has three main advantages over traditional techniques: i it provides models whose accuracy does not depend on input statistics, ii it o ers a wide range of tradeo between accuracy and complexity, and iii it enables the construction of pattern-dependent conservative upper bounds.
Elsevier eBooks, 2002
Dynamic power management (DPM) is a design methodology for dynamically reconfiguring systems to p... more Dynamic power management (DPM) is a design methodology for dynamically reconfiguring systems to provide the requested services and performance levels with a minimum number of active components or a minimum load on such components. DPM encompasses a set of techniques that achieves energy-efficient computation by selectively turning off (or reducing the performance of) system components when they are idle (or partially unexploited). In this paper, we survey several approaches to system-level dynamic power management. We first describe how systems employ power-manageable components and how the use of dynamic reconfiguration can impact the overall power consumption. We then analyze DPM implementation issues in electronic systems, and we survey recent initiatives in standardizing the hardware/software interface to enable software-controlled power management of hardware components. Index Terms-Energy conservation, energy management, optimization methods. I. INTRODUCTION M OST ELECTRONIC circuits and system designs are confronted with the problem of delivering high performance with a limited consumption of electric power. High performance is required by the increasingly complex applications (e.g., multimedia) that are running even on portable devices. Low-power consumption is required to achieve acceptable autonomy in battery-powered systems, as well as to reduce the environmental impact (e.g., heat dissipation, cooling-induced noise) and operation cost of stationary systems. In other words, achieving highly energy-efficient computation is a major challenge in electronic design. Electronic systems can be viewed as collections of components, which may be heterogeneous in nature. Some components may have mechanical parts, e.g., hard-disk drives (HDD's), or optical parts, e.g., displays. For example, a cellular telephone has a digital very large scale integration (VLSI) component, an analog radio-frequency (RF) component, and a display. Such components may be active at different times, and correspondingly consume different fractions of the telephone power budget. Similarly, main components of portable Manuscript
ACM Transactions on Design Automation of Electronic Systems, Jul 1, 2000
Register-transfer level (RTL) power estimation is a key feature for synthesis-based design flows.... more Register-transfer level (RTL) power estimation is a key feature for synthesis-based design flows. The main challenge in establishing a sound RTL power estimation methodology is the construction of accurate, yet efficient, models of the power dissipation of functional macros. Such models should be automatically built, and should produce reliable average power estimates. In this paper we propose a general methodology for building and tuning RTL power models. We address both hard macros (presynthesized functional blocks) and soft macros (functional units for which only a synthesizable HDL description is provided). We exploit linear regression and its nonparametric extensions to express the dependency of power dissipation on input and output activity. Bottom-up off-line characterization of regression-based power macromodels is discussed in detail. Moreover, we introduce a low overhead on-line characterization method for enhancing the accuracy of off-line characterization.
Springer eBooks, 2008
Dynamic Power Management is a design methodology aiming at reducing power consumption of electron... more Dynamic Power Management is a design methodology aiming at reducing power consumption of electronic systems, by performing selective shutdown of the idle system resources. The effectiveness of a power management scheme depends critically on an accurate modeling of the environment, and on the computation of the control policy. This paper presents two methods for characterizing nonstationary service requests by means of a prediction scheme based on sliding windows. Moreover, it describes how control policies for non-stationary models can be derived.
IEEE Access, 2022
Mobile crowdsensing (MCS) is a well-established paradigm that leverages mobile devices' ubiquitou... more Mobile crowdsensing (MCS) is a well-established paradigm that leverages mobile devices' ubiquitous nature and processing capabilities for large-scale data collection to monitor phenomena of common interest. Crowd-powered data collection is significantly faster and more cost-effective than traditional methods. However, it poses challenges in assessing the accuracy and extracting information from large volumes of user-generated data. SmartRoadSense (SRS) is an MCS technology that utilises sensors embedded in mobile phones to monitor the quality of road surfaces by computing a crowdsensed road roughness index (referred to as P PE). The present work performs statistical modelling of P PE to analyse its distribution across the road network and elucidate how it can be efficiently analysed and interpreted. Joint statistical analysis of open datasets is then carried out to investigate the effect of both internal and external road features on P PE. Several road properties affecting P PE as predicted are identified, providing evidence that SRS can be effectively applied to assess road quality conditions. Finally, the effect of road category and the speed limit on the mean and standard deviation of P PE is evaluated, incorporating previous results on the relationship between vehicle speed and P PE. These results enable more effective and confident use of the SRS platform and its data to help inform road construction and renovation decisions, especially where a lack of resources limits the use of conventional approaches. The work also exemplifies how crowdsensing technologies can benefit from open data integration and highlights the importance of making coherent, comprehensive, and well-structured open datasets available to the public.
Springer eBooks, 1997
The presence of large current peaks on the power and ground lines is a serious concern for design... more The presence of large current peaks on the power and ground lines is a serious concern for designers of synchronous digital circuits. Current peaks are caused by the simultaneous switching of highly loaded clock lines and by the signal propagation through the sequential logic elements. In this work we propose a methodology for reducing the amplitude of the current peaks. This result is obtained by clock skew optimization. We propose an algorithm that, for a given clock cycle time, determines the clock arrival time at each flip-flop in order to minimize the current peaks while respecting timing constraint. Our results on benchmark circuits show that current peaks can be reduced without penalty on cycle time and average power dissipation. Our methodology is therefore well-suited for low-power systems with reduced supply voltage, where low noise margins are a primary concern.
IEEE Transactions on Very Large Scale Integration Systems, Jun 1, 2000
Dynamic power management (DPM) is a design methodology for dynamically reconfiguring systems to p... more Dynamic power management (DPM) is a design methodology for dynamically reconfiguring systems to provide the requested services and performance levels with a minimum number of active components or a minimum load on such components. DPM encompasses a set of techniques that achieves energy-efficient computation by selectively turning off (or reducing the performance of) system components when they are idle (or partially unexploited). In this paper, we survey several approaches to system-level dynamic power management. We first describe how systems employ power-manageable components and how the use of dynamic reconfiguration can impact the overall power consumption. We then analyze DPM implementation issues in electronic systems, and we survey recent initiatives in standardizing the hardware/software interface to enable software-controlled power management of hardware components. Index Terms-Energy conservation, energy management, optimization methods. I. INTRODUCTION M OST ELECTRONIC circuits and system designs are confronted with the problem of delivering high performance with a limited consumption of electric power. High performance is required by the increasingly complex applications (e.g., multimedia) that are running even on portable devices. Low-power consumption is required to achieve acceptable autonomy in battery-powered systems, as well as to reduce the environmental impact (e.g., heat dissipation, cooling-induced noise) and operation cost of stationary systems. In other words, achieving highly energy-efficient computation is a major challenge in electronic design. Electronic systems can be viewed as collections of components, which may be heterogeneous in nature. Some components may have mechanical parts, e.g., hard-disk drives (HDD's), or optical parts, e.g., displays. For example, a cellular telephone has a digital very large scale integration (VLSI) component, an analog radio-frequency (RF) component, and a display. Such components may be active at different times, and correspondingly consume different fractions of the telephone power budget. Similarly, main components of portable Manuscript
We introduce the design methodology known as dynamic power management (DPM), targtting the maximi... more We introduce the design methodology known as dynamic power management (DPM), targtting the maximization of power efficiency under performance constroints for electronic s,stemt. We first describe the basic motivations for implementing DPM, then we surve'l several power management ,chemes. Finally, we provide guidelines to assessing the potential impact of a DPM scheme for a given target system.
IEEE Access, 2017
The diffusion of mobile devices equipped with sensing, computation, and communication capabilitie... more The diffusion of mobile devices equipped with sensing, computation, and communication capabilities is opening unprecedented possibilities for high-resolution, spatio-temporal mapping of several phenomena. This novel data generation, collection, and processing paradigm, termed crowdsensing, lays upon complex, distributed cyberphysical systems. Collective data gathering from heterogeneous, spatially distributed devices inherently raises the question of how to manage different quality levels of contributed data. In order to extract meaningful information, it is, therefore, desirable to the introduction of effective methods for evaluating the quality of data. In this paper, we propose an approach aimed at systematic accuracy estimation of quantities provided by end-user devices of a crowd-based sensing system. This is obtained thanks to the combination of statistical bootstrap with uncertainty propagation techniques, leading to a consistent and technically sound methodology. Uncertainty propagation provides a formal framework for combining uncertainties, resulting from different quantities influencing a given measurement activity. Statistical bootstrap enables the characterization of the sampling distribution of a given statistics without any prior assumption on the type of statistical distributions behind the data generation process. The proposed approach is evaluated on synthetic benchmarks and on a real world case study. Cross-validation experiments show that confidence intervals computed by means of the presented technique show a maximum 1.5% variation with respect to interval widths computed by means of controlled standard Monte Carlo methods, under a wide range of operating conditions. In general, experimental results confirm the suitability and validity of the introduced methodology. INDEX TERMS Distributed information systems, measurement uncertainty, statistical analysis, sensor systems and applications.
IEEE Access, 2020
Assessment of balance by means of posturographic analysis is frequently used in the clinical prac... more Assessment of balance by means of posturographic analysis is frequently used in the clinical practice for evaluating the risk of falls or as an indicator of balance-related disorders. The development of automatic, affordable and accurate systems for gauging balance capabilities in the elderly is deemed a crucial step towards the adoption of prevention strategies and the reduction of associated social costs, especially in a context of growing average age of population. In this article we propose to exploit signals that can be collected from sensors on board of common consumer-grade smartphones for posturographic analysis. To this aim, we introduce several processing algorithms for extracting useful information from the acceleration data streams, and we also present an assessment framework based on the comparison of the trajectory of the body center of gravity, estimated from embedded triaxial accelerometers, with a homologous counterpart, estimated from the reference plate force, thus adding to the consistency of the whole process. Experimental results confirm the effectiveness of the proposed system in terms of its capability of achieving signals and posturographic features which agree with those obtained by means of balance board platforms, potentially opening the way to novel research studies and applications of mobile technology in this field.
Kluwer Academic Publishers eBooks, Dec 21, 2005
Virtual memory is considered to be an unlimited resource in desktop or notebook computers with hi... more Virtual memory is considered to be an unlimited resource in desktop or notebook computers with high storage memory capabilities. However, in wireless mobile devices like palmtops and personal digital assistants (PDA), storage memory is limited or absent due to weight, size and power constraints. As a consequence, swapping over remote memory devices can be considered as a viable alternative. Nevertheless, power hungry wireless network interface cards (WNIC) may limit the battery lifetime and application performance if not efficiently exploited. In this work we explore performance and energy of network swapping in comparison with swapping on local micro-drives and flash memories. Our study points out that remote swapping over powermanageable WNICs can be more efficient than local swapping and that both energy and performance can be optimized through power-aware reshaping of data requests. Experimental results show that our optimization technique can save up to 60% of communication energy while improving performance.
Journal of Communications and Networks, Oct 1, 2019
Readily available and affordable consumer-grade electronics, with ever-increasing sensing, comput... more Readily available and affordable consumer-grade electronics, with ever-increasing sensing, computing, and communication capabilities, have provided the ground for distributed computation and data collection systems. Crowd-sensing applications rely on volunteers providing access to their personal devices-a category encompassing smartphones, wearables, vehicles, and a wide range of 'Internet of Things' appliances-and using them as sensors. These systems rely on the willingness of participants to invest in a common cause, which often entails explicit efforts from users, occupation of hardware resources, and risks of sharing private data. Incentives and rewarding schemes are adopted to encourage user participation. This paper introduces the "Worth One Minute" (WOM) platform: an implementation of a generalpurpose rewarding system based on anonymous vouchers. The platform is designed to reward user efforts towards the common good, rewarding their contributions and the intrinsic social value they provide, while preserving their anonymity.
Worth One Minute (WOM) is a general-purpose rewarding system based on the exchange of anonymous v... more Worth One Minute (WOM) is a general-purpose rewarding system based on the exchange of anonymous vouchers. It is designed to support crowd-sensing applications that rely on the willingness of users to participate and invest in common causes. The platform rewards the effort of users toward such causes, thus triggering virtuous circles contributing to the expected social value. The system's reliability depends on the security conditions of the voucher issuing and spending processes. These processes are based on two cryptographic protocols, which are discussed in this paper and formally validated through the automated verification tool ProVerif.
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Papers by Alessandro Bogliolo