Dirk Desmet

Energy-aware runtime scheduling for embedded-multiprocessor SOCs

This task-scheduling method for embedded systems combines the low runtime complexity of a design-time scheduling phase with the flexibility of a runtime scheduling phase.

Design of Cam-E-leon, a run-time reconfigurable web camera

This paper describes the design of a reconfigurable Internet camera, Cam-E-leon, combining reconfigurable hardware and embedded software. The software is based on the µClinux operating system. The network appliance implements a secure VPN (Virtual Private Network) with 3DES encryption and Internet camera server (including JPEG compression). The appliances hardware can be reconfigured at run-time by the client, thus allowing to switch between several available image manipulation functions. The reconfiguration information is retrieved from a reconfiguration server on the network, thus allowing a flexible implementation of new services.The paper describes the hardware and software architecture of the platform, the run-time reconfiguration features of the platform including the integration of the platform in the network, and the design process followed to implement the appliance starting from a high-level executable specification.

Dynamic scheduling of concurrent tasks with cost performance trade-off

This paper addresses the run time task scheduling problem on a multiprocessor platform for embedded systems, where energy consumption is a major concern, as opposed to the traditional static and dynamic scheduling approaches. Our approach intends to combine the advantages of the low run time complexity of the static scheduler and the exibility of the dynamic scheduler and to optimize the system energy consumption at run time based on precomputed costperformance Pareto curves. We have applied our method to an ADSL modem application and the result shows the e ectiveness of our method.

Design of a secure, intelligent, and reconfigurable Web cam using a C based system design flow

This paper describes the design of a reconfigurable Internet camera, Cam-E-leon, combining reconfigurable hardware and embedded software. The software is based on the /spl mu/Clinux operating system. The network appliance implements a secure VPN (virtual private network) with 3DES encryption and Internet camera server (including JPEG compression). The appliances hardware can be reconfigured at run-time by the client, thus allowing us to switch between several available image manipulation functions. This paper focuses on the design process used to implement the appliance starting from a high-level executable specification.

Estimation of foot joint kinetics in three and four segment foot models using an existing proportionality scheme: Application in paediatric barefoot walking

Recent studies which estimated foot segment kinetic patterns were found to have inconclusive data on one hand, and did not dissociate the kinetics of the chopart and lisfranc joint. The current study aimed therefore at reproducing independent, recently published three-segment foot kinetic data (Study 1) and in a second stage expand the estimation towards a four-segment model (Study 2). Concerning the reproducibility study, two recently published three segment foot models (Bruening et al., 2014; Saraswat et al., 2014) were reproduced and kinetic parameters were incorporated in order to calculate joint moments and powers of paediatric cohorts during gait. Ground reaction forces were measured with an integrated force/pressure plate measurement set-up and a recently published proportionality scheme was applied to determine subarea total ground reaction forces. Regarding Study 2, moments and powers were estimated with respect to the Instituto Ortopedico Rizzoli four-segment model. The proportionality scheme was expanded in this study and the impact of joint centre location on kinetic data was evaluated. Findings related to Study 1 showed in general good agreement with the kinetic data published by Bruening et al. (2014). Contrarily, the peak ankle, midfoot and hallux powers published by Saraswat et al. (2014) are disputed. Findings of Study 2 revealed that the chopart joint encompasses both power absorption and generation, whereas the Lisfranc joint mainly contributes to power generation. The results highlights the necessity for further studies in the field of foot kinetic models and provides a first estimation of the kinetic behaviour of the Lisfranc joint.

A color-code based method for the interpretation of plantar pressure measurements in clinical gait analysis

Comparing plantar pressure measurements (PPM) of a patient following an intervention or between a reference group and a patient-group is common practice in clinical gait analysis. However, this process is often time consuming and complex, and commercially available software often lacks powerful visualization and interpretation tools. In this paper, we propose a simple method for displaying pixel-level PPM deviations relative to a so-called reference PPM pattern. The novel method contains 3 distinct stages: (1) a normalization of pedobarographic fields (for foot length and width), (2) a pixel-level z-score based calculation and, (3) color coding of the normalized pedobarographic fields. The methodological steps associated to this novel method are precisely described and clinical output illustrated. We believe that the advantages of the novel method cover several domains. The strongest advantage of the novel method is that it provides a straightforward visual interpretation of PPM without decreasing the resolution perspective. A second advantage is that it may guide the selection of a local mapping technique (data reduction technique). Finally, it may be easily used as education tool during the therapist-patient interaction.

Mapping concurrent applications on network-on-chip platforms

Networks-on-chip have been proposed as the interconnect solution for building large systems-on-chip. Such platforms will be made of hardware cores, running concurrently to achieve high compute power and keep power consumption low. These platforms have many things in common with distributed systems. In this article we analyze the issues related to mapping concurrent applications on a networks-on-chip based platform. We show that the quality of the decisions made at different stages of mapping has a high impact on the overall system performance. The critical stages of application mapping for networks-on-chip platforms include partitioning the application into processing cores, mapping the communication between the cores, and resolving platform-dependent problems such as race conditions and multipoint-to-point communications. We investigate these problems using an MPEG4 video decoder application and we evaluate the performance of the mapped system in a simulation environment, using a SystemC networks-on-chip simulator.

A novel method of quantifying gait deviations using plantar pressure patterns

BACKGROUND Comparing the dynamic pedobarographic patterns of individuals is common practice in basic and applied research. However, this process is often time-consuming and complex, and commercially available software often lacks powerful visualization and interpretation tools. METHODS We propose a simple method for displaying pixel-level pedobarographic deviations over time relative to a so-called reference pedobarographic pattern. This novel method contains four distinct automated preprocessing stages: 1) normalization of pedobarographic fields (for foot length and width), 2) temporal normalization, 3) a pixel-level z-score-based calculation, and 4) color coding of the normalized pedobarographic fields. Group and patient-level comparisons were illustrated using an experimental data set including diabetic and nondiabetic patients. RESULTS The automated procedure was found to be robust and quantified distinct temporal deviations in pedobarographic fields. CONCLUSIONS The advantages of the novel method cover several domains, including visualization, interpretation, and education.