scholarly journals Target Registration Errors in Navigation-assisted Mandibular Surgery According to the Tracking Methods and the Type of Markers

2020 ◽  
Author(s):  
Hee-Guen Kang ◽  
Sang-Hoon Kang ◽  
Young-Don Son ◽  
Hang-Keun Kim
Keyword(s):  
Tracking System ◽  
Anatomical Landmarks ◽  
Registration Errors ◽  
Different Types ◽  
Noninvasive Marker ◽  
Noninvasive Markers ◽  
Maximum Increment ◽  
Mandibular Surgery

Abstract Background: This study was conducted to evaluate the accuracy of navigation process according to the type of tracking methods and registration markers. The target registration errors (TREs) were measured at seven anatomical landmarks of the mandible for evaluation. Methods: Four different experiments were performed to obtain the TREs using two different tracking methods, the optical tracker (Polaris) and the electromagnetic (EM) tracker (Aurora), and two different types of registration markers, invasive and noninvasive markers. All comparisons of TREs were statistically analyzed using SPSS and Python-based statistical package (Pingouin). Results: The average TRE values obtained from the four different experiments were as follows: 1) 0.85 mm using invasive marker and Aurora, 2) 1.06 mm using invasive marker and Polaris, 3) 1.43 mm using noninvasive marker and Aurora, and 4) 1.57 mm using noninvasive marker and Polaris. All comparisons among the type of markers and the seven anatomical landmarks revealed statistically significant differences, except for the type of tracking system. Although the comparison between the modality of the tracking system showed no significant differences, the EM-based approach consistently demonstrated better performances than the optical type in all comparisons. Conclusions: This study demonstrates that, irrespective of the tracking modality, the invasive marker is a better choice in terms of accuracy. When using the noninvasive marker, it is important to consider the increased TREs. In the present study, the noninvasive marker caused a maximum increment of TREs of approximately 0.81 mm compared with the invasive marker. Furthermore, EM-based tracking using an invasive marker may result in the best accuracy for the mandible.

History, Variations, and Extensions of the Retrosigmoid Approach: Anatomical and Literature Review

2021 ◽  
Author(s):  
Jaafar Basma ◽  
Christos Anagnostopoulos ◽  
Andrei Tudose ◽  
Mikhail Harty ◽  
L. Madison Michael ◽  
...  
Keyword(s):  
Cerebellopontine Angle ◽  
Jugular Foramen ◽  
Retrosigmoid Approach ◽  
Anatomical Landmarks ◽  
Posterior Fossa Surgery ◽  
Different Types ◽  
Microsurgical Techniques ◽  
Subarachnoid Spaces ◽  
Far Lateral ◽  
Suboccipital Approach

AbstractThe retrosigmoid approach is the workhorse for posterior fossa surgery. It gives a versatile corridor to tackle different types of lesions in and around the cerebellopontine angle. The term “extended” has been used interchangeably in the literature, sometimes creating confusion. Our aim was to present a thorough analysis of the approach, its history, and its potential extensions. Releasing cerebrospinal fluid from the subarachnoid spaces and meticulous microsurgical techniques allowed for the emergence of the retrosigmoid approach as a unilateral variation of the traditional suboccipital approach. Anatomical landmarks are helpful in localizing the venous sinuses and planning the craniotomy, and Rhoton's rule of three is the key to unlock difficult neurovascular relationships. Extensions of the approach include, among others, the transmastoid, supracerebellar, far-lateral, jugular foramen, and perimeatal approaches. The retrosigmoid approach applies to a broad range of pathologies and, with its extensions, can provide adequate exposure, obviating the need for extensive and complicated approaches.

scholarly journals Mapping numerical perception and operations in relation to functional and anatomical landmarks of human parietal cortex

2019 ◽  
Author(s):  
Elisa Castaldi ◽  
Alexandre Vignaud ◽  
Evelyn Eger
Keyword(s):  
Middle Part ◽  
Anatomical Landmarks ◽  
Functional Neuroanatomy ◽  
Different Types ◽  
Functional Equivalent ◽  
Human Adults ◽  
Ventral Intraparietal Area ◽  
Numerosity Perception ◽  
7T Fmri ◽  
Numerical Operations

AbstractHuman functional imaging has identified the middle part of the intraparietal sulcus (IPS) as an important brain substrate for different types of numerical tasks. This area is often equated with the macaque ventral intraparietal area (VIP) where neuronal selectivity for non-symbolic numbers is found. However, the low spatial resolution and whole-brain averaging analysis performed in most fMRI studies limit the extent to which an exact correspondence of activation in different numerical tasks with specific sub-regions of the IPS can be established. Here we disentangled the functional neuroanatomy of numerical perception and operations (comparison and calculation) by acquiring high-resolution 7T fMRI data in a group of human adults, and relating the activations in different numerical contrasts to anatomical and functional landmarks on the cortical surface. Our results reveal a functional heterogeneity within human intraparietal cortex where the visual field map representations in superior/medial parts of IPS and superior parietal gyrus are involved predominantly in numerosity perception, whereas numerical operations predominantly recruit lateral/inferior parts of IPS. Since calculation and comparison-related activity fell mainly outside the field map representations considered the functional equivalent of the monkey VIP/LIP complex, the areas most activated during such numerical operations in humans are likely different from VIP.

scholarly journals Perception of Esthetic Orthodontic Appliances: An Eye Tracking and Cross-sectional study

2019 ◽  
Vol 90 (1) ◽  
pp. 109-117
Author(s):  
Moritz Försch ◽  
Lena Krull ◽  
Marlene Hechtner ◽  
Roman Rahimi ◽  
Susanne Wriedt ◽  
...  
Keyword(s):  
Eye Tracking ◽  
Visual Analog Scale ◽  
Tracking System ◽  
Fixation Time ◽  
Orthodontic Appliances ◽  
Subjective Perception ◽  
Anatomical Landmarks ◽  
Analog Scale ◽  
Lingual Appliance ◽  
Group D

ABSTRACT Objective To evaluate the perception of esthetic orthodontic appliances by means of eye-tracking measurements and survey investigation. Materials and Methods En face and close-up images with different orthodontic appliances (aligner appliance [a], aligner appliance and attachments [b], lingual appliance [c], ceramic brackets [d], no appliance [e; control]) were shown to 140 participants. Eye movement and gaze direction was recorded by eye-tracking system. For different anatomical areas and areas of the appliances, time to first fixation and total fixation time were recorded. The questions included in a visual analog scale regarding individual sentiency were answered by the participants. Results For all groups, the anatomical landmarks were inspected in the following order: (1) eyes, (2) mouth, (3) nose, (4) hair, and (5) ears. Only in group d, first fixation was on the mouth region (1.10 ± 1.05 seconds). All appliances except the lingual appliance (1.87 ± 1.31 seconds) resulted in a longer fixation on the mouth area (a, 2.97 ± 1.32 seconds; b, 3.35 ± 1.38 seconds; d, 3.29 ± 1.36 seconds). For close-up pictures, the fastest (0.58 seconds) and longest (3.14 seconds) fixation was found for group d, followed by group b (1.02 seconds/2.3 seconds), group a (2.57 seconds/0.83 seconds), and group c (3.28 seconds/0.05 seconds). Visual analog scale scoring of questions on visibility were consistent with eye-tracking measurements. With increasing visibility, the feeling of esthetic impairment was considered higher. Conclusions Lingual orthodontic appliances do not change how the face is perceived. Other esthetic orthodontic appliances may change the pattern of facial inspection and are different in subjective perception.

Selection of Sensors for Heliostat of Concentrated Solar Thermal Tower Power Plant

2021 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Kamran Mahboob ◽  
Qasim Awais ◽  
Awais Khan ◽  
Tabish Fawad ◽  
Momen Rasool ◽  
...  
Keyword(s):  
Power Plant ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Tracking System ◽  
Solar Thermal ◽  
Solar Photovoltaic ◽  
System A ◽  
The World ◽  
Different Types ◽  
Selection Of

As the energy demand of the world is rising, more and more efforts are being made to harness different forms of energy available. Current pollution due to fossil fuels has directed the world to shift to cleaner renewable energies, such as solar. Photovoltaic, as well as concentrated solar technologies, are developed to harness solar energy. The concentrated solar tower power plant is an emerging technology and is under development having vast areas of improvement. The efficiency of the concentrated solar tower power plant depends upon the accuracy of the tracking system of the heliostats placed all around the central tower of the plant. A closed-loop tracking system a feedback method is a need. In addition, to check the accuracy of the system, a calibration system is required. This system uses different types of sensors. In this study, an effort is made to enlist different types of sensors available and their use in the tracking system of the solar thermal tower power plant. In addition, different sensors are suggested that are best suited for calibration and correction purposes.

scholarly journals Comprehensive Methodology to Evaluate Parasitic Energy Consumption for Different Types of Dual-Axis Sun Tracking Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ming-Hui Tan ◽  
Tze-Koon Wang ◽  
Chee-Woon Wong ◽  
Kok-Keong Chong ◽  
Boon-Han Lim ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Loss ◽  
Tracking System ◽  
Electrical Energy ◽  
Photovoltaic System ◽  
The Sun ◽  
Tracking Systems ◽  
Optical Efficiency ◽  
Different Types ◽  
Energy Consumptions

A dual-axis sun tracking system is an essential strategy to maximize the optical efficiency of harnessing solar energy. However, there is no significant study yet to optimize the net performance of the photovoltaic (PV) or concentrator photovoltaic (CPV) system equipped with a dual-axis sun tracking system. Parasitic energy loss associated with the power consumption of the sun tracking system is one of the major concerns for the solar industrial players. To address this issue, a comprehensive methodology has been developed to evaluate the yearly cumulative range of motion for dual-axis sun tracking systems in the cases of with and without fixed parking positions across the latitudes ranging from 45°N to 45°S. The parasitic energy consumptions have been investigated for three selected types of dual-axis sun tracking systems, i.e., the azimuth-elevation sun tracking system (AE-STS), polar dual-axis sun tracking system (PD-STS), and horizontal dual-axis sun tracking system (HD-STS). The simulated results indicate that the dual-axis sun tracking system with the nonfixed parking (or stow) position has lower yearly cumulative parasitic energy consumption with respect to the sun tracking system with a fixed parking position. Lastly, our simulation result has shown that the parasitic energy consumption of the sun tracking is relatively smaller to that of the electrical energy generated by the concentrator photovoltaic system with the ratio between 0.15% and 0.29% for AE-STS, between 0.15% and 0.30% for PD-STS, and between 0.17% and 0.35% for HD-STS.

scholarly journals The New Objects of Forensic Vehicle Examinations

2019 ◽  
Vol 14 (2) ◽  
pp. 84-91 ◽  
Author(s):  
V. G. Grigoryan
Keyword(s):  
Road Traffic ◽  
Tracking System ◽  
Classical Mechanics ◽  
Material Object ◽  
Object Movement ◽  
Different Types ◽  
Forensic Institutions ◽  
Movement Parameters ◽  
Key Techniques ◽  
The Mathematical Model

Forensic vehicle examination is one of the most demanded examination types in the state forensic institutions of the Russian Ministry of Justice.Forensic vehicle examination is based on the core sciences such as physics, mathematics, classical mechanics, theory of a vehicle etc. as well as on criminalistics, provisions and norms of criminal, civil, arbitration and administrative law. Based on  the kinematics and dynamics laws and theorems of a material object movement, key techniques and methodological recommendations on conducting forensic vehicle examination were developed. However, these techniques cannot be applied in cases when values of relevant parameters which are a part of the mathematical model are absent. Although the latest advances in science have made it now possible to identify the movement parameters of those involved in a road traffic accident by examining new objects. Some examples of using such objects in practice are given in the article, for instance of the satellite tracking system, different types of video fixation, supplemental restraint system (SRS) in a car. 

Energy Production of Different Types and Orientations of Photovoltaic Systems Under Outdoor Conditions

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Sebastijan Seme ◽  
Jože Požun ◽  
Bojan Štumberger ◽  
Miralem Hadžiselimović
Keyword(s):  
Energy Production ◽  
Meteorological Parameters ◽  
Tracking System ◽  
Photovoltaic System ◽  
Solar Irradiation ◽  
Photovoltaic Systems ◽  
The South ◽  
Optimal Orientation ◽  
Different Types ◽  
The Impact

This work compares the energy production of different types and orientations of photovoltaic systems under the equal outdoor conditions over the 4-yr period in Slovenia. The following photovoltaic systems were analyzed: the fixed photovoltaic system oriented to the south tilted at 30 deg, the fixed photovoltaic system oriented to the east tilted at 30 deg, the single axis photovoltaic tracking system tilted at 30 deg, and the fixed photovoltaic system oriented to the south tilted at 15 deg. The same monocrystalline silicon (mc-Si) solar modules are used in the compared systems. The systems are installed in a radius of 20 m. This provides the same meteorological parameters during the measured period. The impact of orientation and inclination on energy production are evaluated. The analysis of the data obtained shows that the energy production of the photovoltaic systems depends on the solar irradiation, temperature of solar modules, efficiency of solar modules, and efficiency of dc-ac inverters. Based on the analysis and measurements for different photovoltaic systems, the optimal orientation and inclination are presented. The results for Slovenia show that the optimal orientation and inclination facing south tilted at 45 deg.

Machine Learning on Soccer Players Position

2022 ◽  
Vol 14 (1) ◽  
pp. 0-0
Keyword(s):  
Machine Learning ◽  
Tracking System ◽  
Supervised Machine Learning ◽  
Machine Learning Techniques ◽  
Soccer Players ◽  
Position Information ◽  
Soccer Match ◽  
Professional Soccer ◽  
Learning Techniques ◽  
Different Types

During the last few years, sports analytics has been growing rapidly. The main usage of this discipline is the prediction of soccer match results, even if it can be applied with interesting results in different areas, such as analysis based on the player position information. In this paper, we propose an approach aimed to recognize the player position in a soccer match, predicting the specific zone in which the player is located in a specific moment. Similar objectives have never been considered yet with our best knowledge. We consider supervised machine learning techniques by considering a dataset obtained through video capturing and tracking system. The data analyzed refer to several professional soccer games captured at the Alfheim Stadium in Tromso, Norway. The approach can be used in real-time, in order to verify if a player is playing according to the guidelines of the coach. In the experimental analysis, three different types of classification have been performed, i.e., three different divisions of the field, reaching the best results with Random Tree Algorithm.

scholarly journals Tracking a Decentralized Linear Trajectory in an Intermittent Observation Environment

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2127
Author(s):  
Wasi Ullah ◽  
Irshad Hussain ◽  
Iram Shehzadi ◽  
Zahid Rahman ◽  
Peerapong Uthansakul
Keyword(s):  
Tracking System ◽  
Fault Detection And Isolation ◽  
Sensor Data ◽  
Processing Unit ◽  
Tracking Systems ◽  
Multiple Faults ◽  
Different Types ◽  
Core Issues ◽  
Types Of Faults

Faults and failures are familiar case studies in centralized and decentralized tracking systems. The processing of sensor data becomes more severe in the presence of faults/failures and/or noise. Effective schemes have been presented for decentralized systems, in the presence of faults only. In some practical scenarios of systems, there are certain interruptions in addition to these faults. These interruptions may occur in the form of noise. However it is expected that the decision about the sensor data is difficult in the presence of noise. This is because the noise adversely affects the communication amongst sensors and the processing unit. More complexity is expected when there are faults and noise simultaneously. To deal with this problem, in addition to existing fault detection and isolation schemes, the Kalman filter is employed. Here, a generic discussion is provided, which is equally applicable to other situations. This work addresses various faults in the presence of noise for decentralized tracking systems. Local single faults and multiple faults in the presence of noise are the core issues addressed in this paper. The proposed work is comprised of a general scenario for a decentralized tracking system followed by a case study of a target tracking scenario with and without noise. The presented schemes are also tested for different types of faults. The proposed work presents effective tracking in the presence of noise and faults. The results obtained demonstrate the acceptable performance of the scheme of this work.

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