56 research outputs found
Wave Prediction and Delay Modeling for Teleoperation via Internet
This paper propose a novel approach for modeling the end-to-end time delay dynamics of the internet using system identification, and use it for controlling real-time internet-based telerobotic operations. When a single model is used, it needs to adapt to the operating conditions before an appropriate control mechanism can be applied. Slow adaptation may result in large transient errors. As an alternative, we propose to use an adaptive multiple model framework, and determine the best model for the current operating conditions to activate the corresponding controller. We employ multivariable wave prediction method to achieve this objective
On-Chip Integrated Functional Near Infra-Red Spectroscopy (fNIRS) Photoreceiver for Portable Brain Imaging
RÉSUMÉ
L'imagerie cérébrale fonctionnelle utilisant la Spectroscopie Fonctionnelle Proche-Infrarouge (SFPI)
propose un outil portatif et non invasif de surveillance de l'oxygénation du sang. SFPI est une technique de
haute résolution temporelle non invasive, sûr, peu intrusive en temps réel et pour l'imagerie cérébrale à
long terme. Il permet de détecter des signaux hémodynamiques à la fois rapides et neuronaux ou lents. Outre les avantages importants des systèmes SFPI, ils souffrent encore de quelques inconvénients,
notamment d’une faible résolution spatiale, d’un bruit de niveau modérément élevé et d’une grande
sensibilité au mouvement. Afin de surmonter les limites des systèmes actuellement disponibles de SFPI non-portables, dans cette thèse, nous en avons introduit une nouvelle de faible puissance, miniaturisée sur une puce photodétecteur frontal destinée à des systèmes de SFPI portables. Elle contient du silicium
photodiode à avalanche (SiAPD), un amplificateur de transimpédance (TIA), et « Quench-Reset », circuits
mis en oeuvre en utilisant les technologies CMOS standards pour fonctionner dans les deux modes :
linéaire et Geiger. Ainsi, elle peut être appliquée pour les deux fNIRS : en onde continue (CW- SFPI) et
pour des applications de comptage de photon unique. Plusieurs SiAPDs ont été mises en oeuvre dans de nouvelles structures et formes (rectangulaires, octogonales, double APDs, imbriquées, netted, quadratiques et hexadecagonal) en utilisant différentes techniques de prévention de la dégradation de bord
prématurée. Les principales caractéristiques des SiAPDs sont validées et l'impact de chaque paramètre ainsi que les simulateurs de l'appareil (TCAD, COMSOL, etc) ont été étudiés sur la base de la simulation et de mesure des résultats. Proposées SiAPDs techniques d'exposition avec un gain de grande avalanche,
tension faible ventilation et une grande efficacité de détection des photons dans plus de faibles taux de comptage sombres. Trois nouveaux produits à haut gain, bande passante (GBW) et à faible bruit TIA sont introduits basés sur le concept de gain distribué, d’amplificateur logarithmique et sur le rejet automatique
du bruit pour être appliqué en mode de fonctionnement linéaire. Le TIA proposé offre une faible consommation, un gain de haute transimpédance, une bande passante ajustable et un très faible bruit
d'entrée et de sortie. Le nouveau circuit mixte trempe-reset (MQC) et un MQC contrôlable (CMQC)
frontaux offrent une faible puissance, une haute vitesse de comptage de photons avec un commandable de
temps de hold-off et temps de réinitialiser. La première intégration sur puce de SiAPDs avec TIA et Photon circuit de comptage a été démontrée et montre une amélioration de l'efficacité de la
photodétection, spécialement en ce qui concerne la sensibilité, la consommation d'énergie et le rapport signal sur bruit.----------ABSTRACT
Optical brain imaging using functional near infra-red spectroscopy (fNIRS) offers a direct and
noninvasive tool for monitoring of blood oxygenation. fNIRS is a noninvasive, safe, minimally
intrusive, and high temporal-resolution technique for real-time and long-term brain imaging. It allows detecting both fast-neuronal and slow-hemodynamic signals. Besides the significant
advantages of fNIRS systems, they still suffer from few drawbacks including low spatial-
resolution, moderately high-level noise and high-sensitivity to movement. In order to overcome
the limitations of currently available non-portable fNIRS systems, we have introduced a new
low-power, miniaturized on-chip photodetector front-end intended for portable fNIRS systems. It
includes silicon avalanche photodiode (SiAPD), Transimpedance amplifier (TIA), and Quench-
Reset circuitry implemented using standard CMOS technologies to operate in both linear and
Geiger modes. So it can be applied for both continuous-wave fNIRS (CW-fNIRS) and also
single-photon counting applications. Several SiAPDs have been implemented in novel structures
and shapes (Rectangular, Octagonal, Dual, Nested, Netted, Quadratic and Hexadecagonal) using
different premature edge breakdown prevention techniques. The main characteristics of the
SiAPDs are validated and the impact of each parameter and the device simulators (TCAD,
COMSOL, etc.) have been studied based on the simulation and measurement results. Proposed
techniques exhibit SiAPDs with high avalanche-gain (up to 119), low breakdown-voltage (around
12V) and high photon-detection efficiency (up to 72% in NIR region) in additional to a low dark-
count rate (down to 30Hz at 1V excess bias voltage). Three new high gain-bandwidth product
(GBW) and low-noise TIAs are introduced and implemented based on distributed-gain concept,
logarithmic-amplification and automatic noise-rejection and have been applied in linear-mode of operation. The implemented TIAs offer a power-consumption around 0.4 mW, transimpedance gain of 169 dBΩ, and input-output current/voltage noises in fA/pV range accompanied with ability to tune the gain, bandwidth and power-consumption in a wide range. The implemented
mixed quench-reset circuit (MQC) and controllable MQC (CMQC) front-ends offer a quenchtime of 10ns, a maximum power-consumption of 0.4 mW, with a controllable hold-off and resettimes. The on-chip integration of SiAPDs with TIA and photon-counting circuitries has been demonstrated showing improvement of the photodetection-efficiency, specially regarding to the
sensitivity, power-consumption and signal-to-noise ratio (SNR) characteristics
Human Vision Inspired Technique Applied to Detect Suspicious Masses in Mammograms
Several competitive techniques have been applied for efficient image segmentation and automatic feature extraction through the literatures. There are a lot of open problems and controversial ambiguities regarding to the mechanism which applied by human eye for image segmentation and feature extraction. Here we have first extracted the human vision technique applied for image segmentation and we have implemented this technique for automatic image segmentation and feature extraction. The features have been categorized into the internal and external modalities. We have introduced the negative curvature minima (NCM) points as a dominant external feature and the textures detected using pulse coupled neural networks (PCNNs) and LAWs methods as the dominant internal feature used by human vision to segment and extracts the features of an image. These features have been used to detect suspicious masses in mammogram images using the proposed human eye inspired technique. The results justify the efficiency of the proposed method
Wave Prediction and Delay Modeling for Teleoperation via Internet
This paper propose a novel approach for modeling the end-to-end time delay dynamics of the internet using system identification, and use it for controlling real-time internet-based telerobotic operations. When a single model is used, it needs to adapt to the operating conditions before an appropriate control mechanism can be applied. Slow adaptation may result in large transient errors. As an alternative, we propose to use an adaptive multiple model framework, and determine the best model for the current operating conditions to activate the corresponding controller. We employ multivariable wave prediction method to achieve this objective
Correlation of MT levels in livers and gills with heavy metals in wild tilapia (Oreochromis mossambicus) from the Klang River, Malaysia
Metallothionein (MT) concentrations in gill and liver tissues of Oreochromis mossambicus were determined to assess biological response of fish to levels of some metals. Metal concentrations in gill and liver tissues of O. mossambicus ranged from 0.6 to 2.6 for Cd, 16 to 52 for Zn, 0.5 to 17 for Cu and 2 to 67 for T–Hg (all in μg/g wet weight, except for T–Hg in ng/g wet weight). Accumulation of Cd, Zn, Cu and Hg (μg/g wet weight) in the liver and gills of O. mossambicus were in the order of liver > gills. The concentrations of Cd, Zn, Cu and Hg in fish tissues were correlated with MT content. The increases in MT levels from the reference area Puchong Tengah compared to the polluted area Kampung Seri Kenangan were 3.4- and 3.8-fold for gills and livers, respectively. The results indicate that MT concentrations were tissue-specific, with the highest levels in the liver. Therefore, the liver can act as a tissue indicator in O. mossambicus in the study area
First record of two hard coral species (Faviidae and Siderastreidae) from Qeshm Island (Persian Gulf, Iran)
Abstrak. Moradi M, Kamrani E, Shokri MR, Ranjbar MS, Hesni MA (2009) Rekaman pertama dua spesies karang keras (Faviidae dan
Siderastreidae) dari Pulau Qeshm (Teluk Persia, Iran). Nusantara Bioscience 2: 34-37. Dua jenis karang keras termasuk Cyphastrea
chalcidicum (Forskal 1775) (Faviidae) dan Coscinaraea monile (Forskal 1775) (Siderastreidae) dikumpulkan dari selatan Pulau Qeshm
(Teluk Persia, Iran) pada akhir tahun 2008. Spesies ini sebelumnya dilaporkan terdapat di Teluk Persia selatan, Teluk Aden, Afrika
Tenggara dan Indo-Pasifik. Tinjauan literatur pada distribusi kedua jenis mengungkapkan bahwa spesies ini pertama kali tercatat dari
Teluk Persia. Temuan ini semakin menunjukkan tingginya keragaman fauna karang di perairan Iran di bagian utara Teluk Persia.
Kata kunci: catatan pertama, Coscinaraea monile, Cyphastrea chalcidicum, Qeshm island, Persian gulf
Fisheries impact on trophic levels: North of the Persian Gulf case study, 2002-2011
468-474There are few documented reports about the trophic structure and catch composition of trawl fishery in the Persian Gulf. In this study, the changes in the marine food webs in the North of Persian Gulf along the Bushehr province coastal water of Iran was determined based on the estimates of the two indicators, mean trophic level (MTI) and Fishing in Balanced (FiB) index for the last decade (2002-2011). The data indicated an increase in total landings (of 49 exploited species), and moderate increasing trend in both MTL and FiB-index was observed. Even though the Iranian coastal fishing has increased over time, it has a low impact on the trophic structure of marine communities in this region. The study suggested that it may be due to occurrence of ‘‘fishing up’’ phenomenon in this area and there is a need to expand fishing to offshore and deep waters for discovery of new and high-TL species
Sexual system and Sexual dimorphism in the shrimp Arete indicus, symbiont with the sea urchin Echinometra mathaei in the Persian Gulf, Iran
259-262The sexual system and sexual dimorphism of the shrimp Arete indicus are described. The following were measured for all shrimp under stereomicroscope to the nearest ±0.01 mm: carapace length (CL), merus length (ML) and carpus length (CrL) of the largest of the first pair of chelipeds, pleural width of the second abdominal segment (PW), and propodus length (PL) of the second (larger) pair of chelipeds. Sex determinations were based on presence of the appendix masculina on the base of the endopod of the second pleopods. With a view to determine whether or not a linear relationship exists between the CL, PL, ML, CrL and PW, the allometric model y = axb was used. A correlation was found between CL and ML in both sexes of Arete indicus. The status of allometry differed among various body parts of both sexes, and degree of allometry differed among various body parts between the sexes. According to ANCOVA, PW, PL, and ML of females are not larger than that of males at any given body size .The CL of Arete indicus females was not larger than the males. Due to observation a few of males with tiny appendices masculina, also based on earlier literature worked on Arete indicus, we believe this species is partially protandric
Mating system in the shrimp Arete indicus, a symbiont of Echinometra mathaei
248-252Due to their solitary life style, it appears that Arete indicus have a ‘search and attend’ mating system. There was a correlation between the body size (carapace length) of males and females found in pairs. There was a tight correlation between the numbers of total spine of their host and the number of individuals inhabiting the urchin. There was a weak and non-significant relationship between the number of males and females present and the volume of their host
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