| Title | Schedule Integration for Time-Triggered Systems |
| Author | *Florian Sagstetter, Martin Lukasiewycz (TUM CREATE, Singapore), Samarjit Chakraborty (TU Munich, Germany) |
| Page | pp. 53 - 58 |
| Keyword | scheduling, time-triggered system, FlexRay |
| Abstract | This paper presents a framework for the schedule
integration of time-triggered systems tailored to the automotive
domain. In-vehicle networks might be very large and complex
such that obtaining a schedule for a fully synchronous system
becomes a challenging task since all bus and processor constraints
as well as end-to-end-timing constraints have to be taken concurrently into account. Existing optimization approaches apply
the schedule optimization to the entire network, limiting their
application due to scalability issues. In contrast, the presented
framework obtains the schedule for the entire network, using
a two-step approach where for each cluster a local schedule is
obtained and the local schedules are finally merged to the global
schedule. This approach is also in accordance with the design
process in the automotive industry where different subsystems are
developed independently to reduce the design complexity and are
finally combined in the integration stage. In this paper, a generic
framework for schedule integration of time-triggered systems is
presented. Further, we show how this framework is implemented
for a FlexRay network using an Integer Linear Programming
(ILP) approach which might also be easily adapted to other
protocols. A realistic case study and a scalability analysis give
evidence of the applicability and efficiency of our approach. |
| Slides |
| Title | Online Estimation of the Remaining Energy Capacity in Mobile Systems Considering System-Wide Power Consumption and Battery Characteristics |
| Author | Donghwa Shin (Seoul National University, Republic of Korea), Woojoo Lee (University of Southern California, U.S.A.), Kitae Kim (Seoul National University, Republic of Korea), Yanzhi Wang, Qing Xie (University of Southern California, U.S.A.), *Naehyuck Chang (Seoul National University, Republic of Korea), Massoud Pedram (University of Southern California, U.S.A.) |
| Page | pp. 59 - 64 |
| Keyword | Low-power design, Power estimation, Smartphone, Battery life, Quality of service |
| Abstract | Emerging mobile systems integrate a lot of functionality into a small form factor with a small energy source in the form of rechargeable battery. This situation necessitates accurate estimation of the remaining energy in the battery such that user applications can be judicious on how they consume this scarce and precious resource. This paper thus focuses on estimating the remaining battery energy in Android OS-based mobile systems. This paper proposes to instrument the Android kernel in order to collect and report accurate subsystem activity values based on real-time profiling of the running applications. The activity information along with offline-constructed, regression-based power macro models for major subsystems in the smartphone yield the power dissipation estimate for the whole system. Next, while accounting for the rate-capacity effect in batteries, the total power dissipation data is translated into the battery’s energy depletion rate, and subsequently, used to compute the battery’s remaining lifetime based on its current state of charge information. Finally, this paper describes a novel application design framework, which considers the batterys state-of-charge (SOC), batterys energy depletion rate, and service quality of the target application. The benefits of the design framework are illustrated by examining an archetypical case, involving the design space exploration and optimization of a GPS-based application in an Android OS. |
| Title | WUCC: Joint WCET and Update Conscious Compilation for Cyber-physical Systems |
| Author | Yazhi Huang, Mengying Zhao, *Chun Jason Xue (City University of Hong Kong, Hong Kong) |
| Page | pp. 65 - 70 |
| Keyword | WCET, code similarity, real time systems |
| Abstract | The cyber-physical system (CPS) is a desirable computing
platform for many industrial and scientific applications.
However, the application of CPSs has two challenges: First, CPSs
often include a number of sensor nodes. Update of preloaded
code on remote sensor nodes powered by batteries is extremely
energy-consuming. The code update issue in the energy sensitive
CPS must be carefully considered; Second, CPSs are often
real-time embedded systems with real-time properties. Worst-Case Execution Time (WCET) is one of the most important
metrics in real-time system design. While existing works only
consider one of these two challenges at a time, in this paper, a
compiler-level optimization, Joint WCET and Update Conscious
Compilation (WUCC), is proposed to jointly consider WCET
and code update for cyber-physical systems. The novelty of
the proposed approach is that the WCET problem and code
update problem are considered concurrently such that a balanced
solution with minimal WCET and minimal code difference can
be achieved. The experimental results show that the proposed
technique can minimize WCET and code difference effectively. |
| Slides |