Gyula Simon

Fast Adaptive Acoustic Localization for Sensor Networks

Sensor networks have proven their usefulness in various acoustic localization applications. Recently, a consistency-function-based algorithm has been proposed, which can provide accurate solutions even if a large number of independent outliers are present in a measurement set. In certain practical cases, e.g., in non-line-of-sight reverberant areas, however, sensors may have cooperative and consistent errors, resulting in bad estimates. In this paper, an adaptive consistency-function-based solution is proposed, which can compensate for cooperative and systematic measurement errors and thus provides accurate results even if the original consistency-function-based algorithm fails. Stochastic initialization is also proposed, which is able to accelerate execution of the algorithm by several orders of magnitude while the global optimum is still provided with arbitrarily high probability.

Magnetic-based vehicle detection with sensor networks

An inexpensive, non-intrusive, energy-efficient magnetic sensor-based solution is proposed, which is able to detect vehicles and estimate their speed. In this paper the measurement algorithm is described in detail, which contains an adaptive auto-offset algorithm, a power-based detector and a correlation-based speed estimator. The performance of the proposed solution is illustrated by real measurement examples.

CSP-Based Sensor Network Architecture for Reconfigurable Measurement Systems

A reconfigurable sensor-networking architecture is proposed, which is constructed from lightweight functional elements running on small virtual machines. The proposed architecture provides a flexible measurement framework that is easily adaptable to changing system requirements in run-time. The system is based on Communicating Sequential Processes and thus provides the possibility of verification and checking of system correctness in order to produce provably robust and reliable measurement systems. The structural deadlock-free property of the network is formally proven.

Design of a sensor network based security system

In this paper a wireless distributed building safety and security framework will be introduced. The main design goals of the system are completely distributed operation, flexibility, robustness, fast response time, and energy efficiency. The framework uses low duty cycle TDMA-based communication scheme, where the scheduling is the result of optimization, based on network discovery measurements. The hardware and software architecture of a prototype system is introduced.

Reconfigurable sensor network architecture for distributed measurement systems

A reconfigurable sensor-networking architecture constructed from lightweight functional elements, running on small virtual machines in parallel is proposed. The proposed architecture provides a flexible measurement system that is easily adaptable to changing system requirements in run-time. It is based on Communicating Sequential Processes and thus provides the possibility of verification and checking of system correctness.

Dynamic Models of a Home Refrigerator

Abstract Home refrigerators produce a substantial part of the annual power consumption in an average household. To further improve the efficiency of these devices, new intelligent control solutions are required. These solutions necessitate the behaviour modeling of the refrigerators. We seek models with as simple structure as possible, since future intelligent controllers may use such models in real time, thus their evaluation must be feasible even on simple microcontrollers. We investigate various dynamic models to describe the behavior of the refrigerator, i.e. the cool-down and warm-up phases. For model parameter identification real data was collected from a real home refrigerator. Data processing, modeling and the parameter identification were performed in MATLAB environment.

Energy-efficient and reliable round-robin TDMA for wireless sensor networks

In this paper a fault-tolerant energy-efficient Time Division Multiple Access (TDMA) based routing scheme is proposed for wireless sensor networks. The proposed system provides guaranteed delivery times and tolerates node and link failures. The software architecture and the performance properties of the system are described.

Extended round-robin TDMA scheduling scheme for wireless sensor networks

In this paper a TDMA based routing scheme is proposed for such wireless sensor networks, where nodes form multiple connected cycles. The proposed method provides fault tolerance, guaranteed delivery times, and low power consumption. The paper discusses the routing scheme and its implementation details, and provides several performance tests.

Accelerometer-Based Event Detector for Low-Power Applications

In this paper, an adaptive, autocovariance-based event detection algorithm is proposed, which can be used with micro-electro-mechanical systems (MEMS) accelerometer sensors to build inexpensive and power efficient event detectors. The algorithm works well with low signal-to-noise ratio input signals, and its computational complexity is very low, allowing its utilization on inexpensive low-end embedded sensor devices. The proposed algorithm decreases its energy consumption by lowering its duty cycle, as much as the event to be detected allows it. The performance of the algorithm is tested and compared to the conventional filter-based approach. The comparison was performed in an application where illegal entering of vehicles into restricted areas was detected.

Lookup: Robust and Accurate Indoor Localization Using Visible Light Communication

A novel indoor localization system is presented, where LED beacons are utilized to determine the position of the target sensor, including a camera, an inclinometer, and a magnetometer. The beacons, which can be a part of the existing lighting infrastructure, transmit their identifiers for long distances using visible light communication techniques. The sensor is able to sense and detect the high-frequency (flicker free) code by properly undersampling the transmitted signal. The localization is performed using novel geometric and consensus-based techniques, which tolerate well measurement inaccuracies and sporadic outliers. The performance of the system is analyzed using simulations and real measurements. According to large-scale tests in realistic environments, the accuracy of the proposed system is in the low decimeter range.