20 research outputs found
Periodicity pitch perception part III: sensibility and Pachinko volatility
Neuromorphic computer models are used to explain sensory perceptions. Auditory models generate cochleagrams, which resemble the spike distributions in the auditory nerve. Neuron ensembles along the auditory pathway transform sensory inputs step by step and at the end pitch is represented in auditory categorical spaces. In two previous articles in the series on periodicity pitch perception an extended auditory model had been successfully used for explaining periodicity pitch proved for various musical instrument generated tones and sung vowels. In this third part in the series the focus is on octopus cells as they are central sensitivity elements in auditory cognition processes. A powerful numerical model had been devised, in which auditory nerve fibers (ANFs) spike events are the inputs, triggering the impulse responses of the octopus cells. Efficient algorithms are developed and demonstrated to explain the behavior of octopus cells with a focus on a simple event-based hardware implementation of a layer of octopus neurons. The main finding is, that an octopus' cell model in a local receptive field fine-tunes to a specific trajectory by a spike-timing-dependent plasticity (STDP) learning rule with synaptic pre-activation and the dendritic back-propagating signal as post condition. Successful learning explains away the teacher and there is thus no need for a temporally precise control of plasticity that distinguishes between learning and retrieval phases. Pitch learning is cascaded: At first octopus cells respond individually by self-adjustment to specific trajectories in their local receptive fields, then unions of octopus cells are collectively learned for pitch discrimination. Pitch estimation by inter-spike intervals is shown exemplary using two input scenarios: a simple sinus tone and a sung vowel. The model evaluation indicates an improvement in pitch estimation on a fixed time-scale
POLE MAGNETYCZNE WSPÓŁOSIOWYCH KWADRATOWYCH CEWEK ZAMKNIĘTYCH W MATERIALE O WYSOKIEJ PERMEANCJI
In this paper, the method of images is used to model the effects of enclosure made of high-permeability material on magnetic field of square coils. Closed-form description for the images, along with the case study involving square Helmholtz coils, is provided.W artykule opisano wykorzystanie metody obrazów do modelowania wpływu obudowy wykonanej z materiału o dużej przenikalności magnetycznej w obszarze kwadratowych cewek. Przedstawiono opis obrazów dla zamkniętej formy wraz ze studium przypadku z kwadratowymi cewkami Helmholtza
Towards Robust Communications of Wireless Sensor Networks in Vehicular Environments: A Case Study
Wireless Sensor Networks are popular solutions for various applications in order to reduce the efforts required by traditional cable-based systems. If the system in question is used to monitor and control physical processes, robust and reliable communication services have to be provided by the network. This is especially true for industrial or vehicular applications where the nodes are deployed in environments facing harsh propagation conditions. Usually, the effect of this on the system performance is studied on isolated layers of the OSI-reference model only. Therefore, we present results from a measurement campaign of vehicular environments that try to estimate the achievable robustness with respect to multiple OSI layers. Our results show that even if the link is rather poor, protocols on the upper layers are able to compensate this at the cost of additional delay
MODELOWANIE MATEMATYCZNE I SYSTEM STEROWANIA BUDYNKIEM NIEMAL ZEROENERGETYCZNYM
The article examines three different kinds of mathematical model of nearly zero energy building. The first model enables to optimize the structure and the definition of key parameters of energy efficient building. The second model is necessary for passive house designing with renewable energy sources. The third model should be used for monitoring and control of energy supply system of nearly zero energy building through year every hour of winter and summer.W artykule rozważono trzy różne typy matematycznego modelu budynku o niemal zerowym zużyciu energii. Pierwszy model pozwala zoptymalizować strukturę i definicję kluczowych parametrów budynku energooszczędnego. Drugi model jest niezbędny do zaprojektowania domu pasywnego wykorzystującego odnawialne źródła energii. Trzeci model powinien być stosowany do godzinowego monitorowania i monitorowania systemu energetycznego budynku o niskim zużyciu energii przez cały rok
On the information content of sensor placement optimization
Figures of merit are used to estimate the information content and to optimize the sensor placement. They are the key to find
an optimal sensor placement, which gives the most available information from a system under investigation with a minimal number of
sensors. In this paper we compare figures of merit used in the literature in order to find a suitable one for estimation of the information
contained in a sensor network
Defect detection in conducting materials using eddy current testing techniques
Lorentz force eddy current testing (LET) is a novel nondestructive testing
technique which can be applied preferably to the identification of internal
defects in nonmagnetic moving conductors. The LET is compared (similar
testing conditions) with the classical eddy current testing (ECT). Numerical
FEM simulations have been performed to analyze the measurements as well as
the identification of internal defects in nonmagnetic conductors. The results
are compared with measurements to test the feasibility of defect
identification. Finally, the use of LET measurements to estimate of the
electrical conductors under test are described as well
Magnetic field of rectangular current loop with sides parallel and perpendicular to the surface of high-permeability material
In this paper, method of current images is used to calculate magnetic field
of a rectangular loop in presence of high-permeability material. We provide
closed form description for the images of the current loop placed between two
semi-infinite blocks of high-permeability material, in the cases when the
plane of the loop is parallel or perpendicular to the surfaces of blocks. A
case study of using the method of images to calculate magnetic field of
rectangular loop inside cube made of high-permeability material is also
provided. [Projekat Ministarstva nauke Republike Srbije, br. TP32016
Mathematical analysis of random telegraph noise in low-power applications of MOSFETs
Silicon MOSFETs are active switching elements
which form the basis for most currently available digital circuits.
Especially in information technology the growth in circuit
complexity and data throughput leads to an increase in
power consumption. For this reason, the energy efficiency of
transistors has become a major design issue. A common way to
increase the energy efficiency of these devices is to reduce the
signal level, which finally leads to the so-called sub-threshold
operation. An advantage of this approach is that it can be
applied to common structures so that new device concepts are not
necessarily required. However, the reduction in the signal level
leads unavoidably to a degradation of the signal to noise ratio.
Especially random telegraph noise has a significant influence on
the circuit behavior. In this work this type of noise is studied
mathematically. A stochastic simulation model was developed and
a method was provided by which it can be determined how low
the supply voltage can be chosen in order to keep the noise
influence sufficiently low