Two research communities, motor systems neuroscience and motor prosthetics, examine the relationship between neural activity in the motor cortex and movement. The former community aims to understand how the brain cont...
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Two research communities, motor systems neuroscience and motor prosthetics, examine the relationship between neural activity in the motor cortex and movement. The former community aims to understand how the brain controls and generates movement; the latter community focuses on how to decode neural activity as control signals for a prosthetic cursor or limb. Both have made progress toward understanding the relationship between neural activity in the motor cortex and behavior. However, these findings are tested using animal models in an environment that constrains behavior to simple, limited movements. These experiments show that, in constrained settings, simple reaching motions can be decoded from small populations of spiking neurons. It is unclear whether these findings hold for more complex, full-body behaviors in unconstrained settings. Here we present the results of freely-moving behavioral experiments from a monkey with simultaneous intracortical recording. We investigated neural firing rates while the monkey performed various tasks such as walking on a treadmill, reaching for food, and sitting idly. We show that even in such an unconstrained and varied context, neural firing rates are well tuned to behavior, supporting findings of basic neuroscience. Further, we demonstrate that the various behavioral tasks can be reliably classified with over 95% accuracy, illustrating the viability of decoding techniques despite significant variation and environmental distractions associated with unconstrained behavior. Such encouraging results hint at potential utility of the freely-moving experimental paradigm.
As far as we know, there is not a Node Localization Algorithm (NLA) that presents the same accuracy for all possible scenarios. We believe that a NLA should be able to "interpret" the dynamic information of ...
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As far as we know, there is not a Node Localization Algorithm (NLA) that presents the same accuracy for all possible scenarios. We believe that a NLA should be able to "interpret" the dynamic information of the environment. In this sense, simple NLAs are rather focused and might perform well for specific scenarios and applications. Therefore, information fusion and context awareness seems to be an appropriate approach to address this issue. We propose the Smart Environmental Architecture for Node Localization (SEA-NL), which is composed by two main elements: (i) the Smart Beacon Nodes (SBNs) and (ii) the Logical Position of Nodes (LPN). In (i) the obstruction level indicator is estimated and can improve the estimation of distances among nodes. In (ii) environment information and a one to one relation between a node and an object are used and can also improve location estimation. Via simulation, our architecture was tested indoors and outdoors considering three localization algorithms: the Weighed Centroid Localization (WCL), the Centroid Localization, and the Triangular Centroid Localization. Finally, we present an accuracy comparison among NLAs used in isolated way, and by using the SBNs, the LPN, and the SEA-NL, where our architecture improves WCL up to ~30.88%.
This work presents a combination of the Model-View-Controller pattern with the Evolutionary Acquisition Interdisciplinary Research Project Management for web services *** intends to promote an increase in productivity...
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This work presents a combination of the Model-View-Controller pattern with the Evolutionary Acquisition Interdisciplinary Research Project Management for web services *** intends to promote an increase in productivity and to facilitate interdisciplinary web services *** consists of an independent database for users' feedback that together with technological opportunities and evolving threats considerations may start a new release of the system allowing a dynamic evolution through acquiring new features or correcting errors,but the new release decision is not *** other words,web service evolution is accomplished adding requirements analysis into the Model-View-Controller pattern,which is incorporated into Interdisciplinary Research Project Management.
Dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. However, demonstrations of dielectric metamaterials have so far been limited to microwave and mid-infr...
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Dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. However, demonstrations of dielectric metamaterials have so far been limited to microwave and mid-infrared frequencies. In this work, we outline the development of purely dielectric zero-index metamaterials operating at optical frequencies. The metamaterial, formed from silicon rods, exhibits impedance matching with air, resulting in unity transmission at the zero-index point. Design and experimental realization of the metamaterials is presented. The metamaterials can potentially be used for a number of applications including compact lens systems, directional emitters, and transformation optics devices.
This study was motivated by the possibility of using N resonant levels interacting with the GaAs conduction band, in GaNxAs1−x (0<x<2.5%), to enhance the density of states effective mass (md) and consequently th...
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This study was motivated by the possibility of using N resonant levels interacting with the GaAs conduction band, in GaNxAs1−x (0electrical conductivity. However, it was observed that, compared with GaAs, the power factor was reduced in spite of a small increase in the md. The influences of carrier passivation and dopant type, as well as the changes in the carrier scattering mechanism, which degrades the carrier mobility, are discussed.
Accurate registration of cardiac first-pass magnetic resonance imaging (FP-MRI) is fundamental for precise analysis of myocardial perfusion. In this paper, we introduce and validate a new framework for accurate regist...
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Accurate registration of cardiac first-pass magnetic resonance imaging (FP-MRI) is fundamental for precise analysis of myocardial perfusion. In this paper, we introduce and validate a new framework for accurate registration of the segmented left ventricle (LV) wall on cardiac FP-MRI. Due to the continuous physiological motion of the heart that causes the LV wall to change shape significantly and to move within and through the image plane, we developed a new methodology for 2D FP-MRI nonrigid registration that includes: (i) global target-to-reference frame-to-frame alignment based on the maximization of the normalized mutual information (NMI);(ii) local alignment based on using a B-splines transformation model that maximizes a similarity function that accounts for 1st- and 2ndorder NMI between the globally aligned frames followed by (iii) a refinement step that is based on deforming each pixel of the target wall over evolving closed equi-spaced contours (iso-contours) to closely match the reference wall. Respective iso-contours in both reference and target frames are matched based on solving the Laplace equation. We have tested our framework on both synthetic phantoms and 20 in-vivo data sets that have been collected from patients with ischemic damage from heart attacks, who are undergoing a novel myoregeneration therapy.
People with neurological disorders like Cerebral Palsy (CP) and Multiple Sclerosis (MS) suffer associated functional gait problems. The symptoms and sign of these gait deficits are different between subjects and even ...
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People with neurological disorders like Cerebral Palsy (CP) and Multiple Sclerosis (MS) suffer associated functional gait problems. The symptoms and sign of these gait deficits are different between subjects and even within a subject at different stage of the disease. Identifying these gait related abnormalities helps in the treatment planning and rehabilitation process. The current gait assessment process does not provide very specific information within the seven gait phases. The objective of this study is to investigate the possible application of granular computing to quantify gait parameters within the seven gait phases. In this process we applied fuzzy-granular computing on the vertical ground reaction force (VGRF) and surface electromyography (sEMG) data to obtain respective characteristic values for each gait phase. A fuzzy similarity (FS) measure is used to compare patient values with age and sex matched control able-bodied group. We specifically applied and tested this approach on 10 patients (4 Cerebral Palsy and 6 Multiple Sclerosis) to identify possible gait abnormalities. Different FS values for VGRF for right and left leg is observed. The VGRF analysis shows smaller FS values during the swing phase in CP and MS subjects that are evidence of associated stability problem. Similarly, FS values for muscle activates of the four-selected muscle display a broad range of values due to difference between subjects. Degraded FS values for different muscles at different stage of the gait cycle are reported. Smaller FS values are sign of abnormal activity of the respective muscles. This approach provides individual centered and very specific information within the gait phases that can be employed for diagnosis, treatment and rehabilitation process.
Fourier transform infrared (FT-IR) spectroscopic imaging provides spatially resolved chemical information. Recent developments have shown that this chemical information can be used to determine tissue cell types. Our ...
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Fourier transform infrared (FT-IR) spectroscopic imaging provides spatially resolved chemical information. Recent developments have shown that this chemical information can be used to determine tissue cell types. Our goal is then to use the spatial distribution of tissue cell types to perform accurate diagnosis of cancer. However, this step is limited by the spatial resolution provided by current imaging systems. In this paper, we demonstrate that these instruments can be designed to provide better spatial resolution for tissue chemistry. We present an optical model for the propagation of light through an FT-IR spectroscopic imaging system. Using this model, we minimally modify an existing FT-IR spectroscopic imaging system to obtain significantly higher resolution and image quality. We demonstrate that it is possible to identify previously obscured tissue types by performing histological classification based on bio-chemically derived spectral features (metrics).
In this study, we focused on the interoperability and authentication of medical devices in the context of telemedical systems. A recent standard called the ISO/IEEE 11073 Personal Health Device (X73-PHD) Standards add...
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ISBN:
(纸本)9781424441198
In this study, we focused on the interoperability and authentication of medical devices in the context of telemedical systems. A recent standard called the ISO/IEEE 11073 Personal Health Device (X73-PHD) Standards addresses the device interoperability problem by defining common protocols for agent (medical device) and manager (appliance) interface. The X73-PHD standard however has not addressed security and authentication of medical devices which is important in establishing integrity of a telemedical system. We have designed and implemented a security policy within the X73-PHD standards. The policy will enable device authentication using Asymmetric-Key Cryptography and the RSA algorithm as the digital signature scheme. We used two approaches for performing the digital signatures: direct software implementation and use of embedded security modules (ESM). The two approaches were evaluated and compared in terms of execution time and memory requirement. For the standard 2048-bit RSA, ESM calculates digital signatures only 12% of the total time for the direct implementation. Moreover, analysis shows that ESM offers more security advantage such as secure storage of keys compared to using direct implementation. Interoperability with other systems was verified by testing the system with LNI Healthlink, a manager software that implements the X73-PHD standard. Lastly, security analysis was done and the system's response to common attacks on authentication systems was analyzed and several measures were implemented to protect the system against them.
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