Many animals are known to maintain an internal estimate of their orientation in the environment. In the absence of external sensory cues, this estimate inevitably exhibits drift. When sensory information is available,...
详细信息
Many animals are known to maintain an internal estimate of their orientation in the environment. In the absence of external sensory cues, this estimate inevitably exhibits drift. When sensory information is available, associations between sensory landmarks and the internal estimate can be used to correct for drift. In this paper we present a neuromorphic system to model such associations between sensory landmarks in the environment (as provided by sonar) and the activity of a hardware-based head direction cell system (HDS) that continuously integrates angular velocity signals to maintain an estimate of the orientation. These associations are shown to correct for drift errors that are encountered in the HDS.
Brain-Machine Interface (BMI) decoding algorithms are often trained offline, but this paradigm ignores both the non-stationarity of neural signals and the feedback that exists in online, closed-loop control. To addres...
详细信息
Brain-Machine Interface (BMI) decoding algorithms are often trained offline, but this paradigm ignores both the non-stationarity of neural signals and the feedback that exists in online, closed-loop control. To address these problems, we have developed an Adaptive Kalman Filter (AKF), a Kalman filter variant that adaptively updates its model parameters during training. For a Kalman filter decoder, batch retraining methods require completely re-estimating the parameter matrices from sufficient data to perform regression accurately, even if only small changes are necessary. Conversely, the AKF is designed to update the decoder parameters continuously and more intelligently. We simulated a population of 41 neurons learning to control a 2D computer cursor. The AKF yielded significantly faster skill acquisition and better robustness to perturbation and neuron loss than a standard Kalman filter with periodic batch retraining.
Enhanced rates of oxide growth have been observed on silicon when exposed to high-energy x-ray irradiation. This observed effect could potentially be utilized for remote total ionizing dose-sensing applications.
Enhanced rates of oxide growth have been observed on silicon when exposed to high-energy x-ray irradiation. This observed effect could potentially be utilized for remote total ionizing dose-sensing applications.
We have investigated the MOVPE growth of InxGa1-xAs metamorphic buffer layer (MBL) structures with a focus on techniques to improve the surface morphology and determine the influence of morphology on subsequently grow...
详细信息
Wireless sensor networks can be used in habitat monitoring for detecting fire, in disaster for helping rescue teams and in agriculture for sensing humidity. Node localization is essential for some important sensor net...
详细信息
Wireless sensor networks can be used in habitat monitoring for detecting fire, in disaster for helping rescue teams and in agriculture for sensing humidity. Node localization is essential for some important sensor network applications. Despite the high relative accuracy of some localization algorithms, node localization is still an opened research area, due to the physical phenomena such as attenuation, reflection, diffraction, scattering and so forth. The current developed algorithms have different accuracy when are tested under dissimilar environments. We propose to use Smart Beacon Nodes (SBNs) to infer the Obstruction Level Indicator over an occupied area, then, use this indicator for estimating the distance among nodes. In our experimental simulation, SBNs decrease the node localization error of Triangular Centroid Localization and Weighted Centroid Localization up to 18%.
Poly(Ε-caprolactone) (PCL) films have been applied for vascular tissue engineering. However, few studies studied the effects of fabrication process of PCL film on vascular cell proliferation. In this study, we used d...
详细信息
ISBN:
(纸本)9781424492763
Poly(Ε-caprolactone) (PCL) films have been applied for vascular tissue engineering. However, few studies studied the effects of fabrication process of PCL film on vascular cell proliferation. In this study, we used different processing methods, incorporating stretching, to fabricate various PCL films. Thickness of films before and after stretch and proliferation ability of human fetal mesenchymal stem cells (hfMSCs) on these films were investigated. Our results showed that stretching significantly reduces the thickness of solvent cast, heat press and cast stretch films (0.22, 0.59, 0.60, p
In this paper we report for the first time the design, fabrication and characterization of an optically transparent electrode array for micro-electrocorticography. We present a 49-channel μECoG array with an electrod...
详细信息
ISBN:
(纸本)9781424441211
In this paper we report for the first time the design, fabrication and characterization of an optically transparent electrode array for micro-electrocorticography. We present a 49-channel μECoG array with an electrode pitch of 800 μm and a 16-channel linear μECoG array with an electrode pitch of 200 μm. The backing material was Parylene C. Transparent, sputtered indium tin oxide (ITO) was used in conjunction with e-beam evaporated gold to fabricate the electrodes. We provide electrochemical impedance characterization and light transmission data for the fabricated devices.
Sepsis is an adverse systemic inflammatory response caused by microbial infection in blood. This paper reports a novel microfluidic approach for non-specific removal of both pathogen and inflammatory cellular componen...
详细信息
ISBN:
(纸本)9781618395955
Sepsis is an adverse systemic inflammatory response caused by microbial infection in blood. This paper reports a novel microfluidic approach for non-specific removal of both pathogen and inflammatory cellular components from whole blood directly using cell margination. A high microbial removal efficiency of > 80% was achieved in our device consisting of 2 cascaded microchannels in series, thus allowing a 2-stage removal of microbes in a single step. ∼90% of platelets and leukocytes were also successfully removed from the blood which can be used to modulate the host inflammatory responses and potentially as a blood cleansing method for sepsis treatment.
We report results of the experimental investigation of the low-frequency noise in graphene transistors. The graphene devices were measured in three-terminal configuration. The measurements revealed low flicker noise l...
详细信息
We report results of the experimental investigation of the low-frequency noise in graphene transistors. The graphene devices were measured in three-terminal configuration. The measurements revealed low flicker noise levels with the normalized noise spectral density close to 1/f (f is the frequency) and the Hooge parameter α H ~10 -3 . Both top-gate and back-gate devices were studied. The analysis of the noise spectral-density dependence on the gate biases helped us to elucidate the noise sources in these devices. We compared the noise performance of graphene devices with that of carbon nanotube devices. It was determined that graphene devices works better than carbon nanotube devices in terms of the low-frequency noise. The obtained results are important for graphene electronic, communication and sensor applications.
We report results of the study of the low-frequency noise in thin films of bismuth selenide topological insulators, which were mechanically exfoliated from bulk crystals via “graphene-like” procedures. From the resi...
详细信息
We report results of the study of the low-frequency noise in thin films of bismuth selenide topological insulators, which were mechanically exfoliated from bulk crystals via “graphene-like” procedures. From the resistance dependence on the film thickness, it was established that the surface conduction contributions to electron transport were dominant. It was found that the current fluctuations have the noise spectral density SI ∞ 1/ f (where f is the frequency) for the frequency range up to 10 kHz. The obtained noise data are important for transport experiments with topological insulators and for any proposed device applications of these materials.
暂无评论