Jan Haase

Power-Aware System Design of Wireless Sensor Networks: Power Estimation and Power Profiling Strategies

Modern design of wireless devices requires the designers to have a special focus on power consumption to prolong the battery life of the final system. The designer therefore needs power consumption information very early in the process to be able to decide on system parameters, design methods, communication protocols, functionality restrictions. Typically, this is done by running simulations of the system to be developed and performing design space exploration. However, there is a tradeoff between speed and accuracy of simulation, therefore the designer has to be aware of available tools and simulation methods he can choose from to achieve the best possible solution for his case.

Using transaction level modeling techniques for wireless sensor network simulation

Wireless Sensor Networks are gaining more and more importance in various application fields. Often, energy autonomy on the node level is an essential nonfunctional constraint to be met. Therefore, when simulating such networks, the energy consumption on the node level has to be included into the simulation. To make this time consuming task feasible, an overall simulation speedup on the network level is desirable. In this paper, we propose to use techniques similar to those used in Transaction Level Models of Bus Systems. 1

Hardware synchronization for embedded multi-core processors

Multi-core processors are about to conquer embedded systems — it is not the question of whether they are coming but how the architectures of the microcontrollers should look with respect to the strict requirements in the field. We present the step from one to multiple cores in this paper, establishing coherence and consistency for different types of shared memory by hardware means. Also support for point-to-point synchronization between the processor cores is realized implementing different hardware barriers. The practical examinations focus on the logical first step from single- to dual-core systems, using an FPGA-development board with two hard PowerPC processor cores. Best- and worst-case results, together with intensive benchmarking of all synchronization primitives implemented, show the expected superiority of the hardware solutions. It is also shown that dual-ported memory outperforms single-ported memory if the multiple cores use inherent parallelism by locking shared memory more intelligently using an address-sensitive method.

Demand response with functional buildings using simplified process models

Smart Grids ideally interconnect intelligent grid members. One big share of grid presence is with buildings. Flexible and grid-friendly buildings would improve grid management and are an important contribution to the integration of renewable energy sources. Classical buildings, however, are passive and not cooperative. This article describes how electro-thermal processes in buildings can be used for demand response and how such intelligent behavior can be enabled via communication technology. Experiments and simulations on typical mid-European buildings were done to estimate the potential time constants.

Mathematical model and control strategy of a two-wheeled self-balancing robot

In this paper a control strategy and sensor concept for a two-wheeled self-balancing robot is proposed. First a mathematical model of the robot is derived using Lagrangian mechanics. Based on the model a full state feedback controller, in combination with two higher-level controls are deployed for stabilization and drive control. A gyroscope, an accelerometer and rotational encoders are used for state determination, introducing a new method of measurement data fusion for the accelerometer and the gyro by using a drift compensation controller. Furthermore measurement proceedings for the model parameters of a real prototype robot are suggested and the control for this robot is designed. The proposed mathematical model, as well as the control strategy are then verified by comparing the behavior of the constructed robot with model simulations.

Energy profiling technique for network-level energy optimization

This work presents an energy profiling technique to optimize energy consumption in networks, with special focus in wireless sensor networks, where energy consumption is usually a major constraint. The approach aims to organize data obtained from power simulation in order to provide useful information to designers at high level abstraction layers, so that they are able to observe the impact of different design decisions, and therefore optimize their designs in terms of energy. Other energy profiling techniques deal only with local scope profiling, in order to optimize the node architecture. However, the energy profiling technique proposed here takes into account network-wide information expanding the scope of energy profiling to energy aware network design and optimization. Finally, the approach is further developed and its possibilities are explored by implementing on a wireless sensor network simulator and using it to optimize energy consumption at the network level in a pilot scenario.

Reliability-Aware Power Management of Multi-Core Processors

Long-term reliability of processors is experiencing growing attention since decreasing feature sizes and increasing power consumption have a negative influence on the lifespan. The reliability can also be influenced by Dynamic Power Management (DPM), since it affects the processor’s temperature.

Bridging MoCs in SystemC specifications of heterogeneous systems

In order to get an efficient specification and simulation of a heterogeneous system, the choice of an appropriate model of computation (MoC) for each system part is essential. The choice depends on the design domain (e.g., analogue or digital), and the suitable abstraction level used to specify and analyse the aspects considered to be important in each system part. In practice, MoC choice is implicitly made by selecting a suitable language and a simulation tool for each system part. This approach requires the connection of different languages and simulation tools when the specification and simulation of the system are considered as a whole. SystemC is able to support a more unified specification methodology and simulation environment for heterogeneous system, since it is extensible by libraries that support additional MoCs. A major requisite of these libraries is to provide means to connect system parts which are specified using different MoCs. However, these connection means usually do not provide enough flexibility to select and tune the right conversion semantic in a mixed-level specification, simulation, and refinement process. In this article, converter channels, a flexible approach for MoC connection within a SystemC environment consisting of three extensions, namely, SystemC-AMS, HetSC, and OSSS+R, are presented.

Real-time wireless communication in automotive applications

Wireless communication in a car has several advantages, given that demanded safety and real-time requirements are fulfilled. This paper presents a wireless MAC protocol designed for the needs of automotive and industrial applications. The proposed MAC protocol provides special support for network traffic prioritization in order to guarantee worst-case message delays for a set of high-prioritized nodes. The performance is further analyzed with a network simulator and compared with the IEEE 802.15.4 standard CSMA/CA protocol.

Energy efficient building automation: A survey paper on approaches and technologies for optimized building operation

Building automation is a trusted technology to ensure user comfort in buildings. Today the challenge is not only to provide comfort, but to do it while having a close eye on the energy performance of the building. Distributed, renewable energy sources, advances in IT and tighter legislative constraints offer and demand changes in the way we operate buildings. We look at the core fields that enable building operation: monitoring of operation data, controls, automation and the management organization to show that innovation can be achieved by integrating cross-domain knowledge and getting inspirations from other domains, where existing approaches and technologies can be used and transferred to the domain of building automation.