Conflict Avoidance Using Flight Speed Control in a High Density Air Corridor

2013 ◽  
Vol 61 (5) ◽  
pp. 119-124 ◽  
Author(s):  
Keisuke FUKUOKA ◽  
Noboru TAKEICHI ◽  
Yoichi NAKAMURA
Keyword(s):  
Speed Control ◽  
High Density ◽  
Flight Speed ◽  
Conflict Avoidance

scholarly journals Behavioural system identification of visual flight speed control in Drosophila melanogaster

2010 ◽  
Vol 8 (55) ◽  
pp. 171-185 ◽  
Author(s):  
Nicola Rohrseitz ◽  
Steven N. Fry
Keyword(s):  
System Identification ◽  
Flight Control ◽  
Closed Loop ◽  
Speed Control ◽  
Control Model ◽  
Open Loop ◽  
Flight Speed ◽  
Level Control ◽  
Wide Range ◽  
Sensory Motor

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila , based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.

scholarly journals Embodied linearity of speed control in Drosophila melanogaster

2012 ◽  
Vol 9 (77) ◽  
pp. 3260-3267 ◽  
Author(s):  
V. Medici ◽  
S. N. Fry
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Hierarchical Control ◽  
Speed Control ◽  
Micro Air Vehicles ◽  
The Body ◽  
Flight Speed ◽  
Free Flight ◽  
Body Angle ◽  
Visual Speed

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles.

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

Triglyceride to high density lipoprotein cholesterol ratio, total cholesterol to high density lipoprotein cholesterol ratio and low ankle brachial index in an elderly population

VASA ◽  
2014 ◽  
Vol 43 (3) ◽  
pp. 189-197 ◽  
Author(s):  
Yiqiang Zhan ◽  
Jinming Yu ◽  
Rongjing Ding ◽  
Yihong Sun ◽  
Dayi Hu
Keyword(s):  
High Density Lipoprotein ◽  
Total Cholesterol ◽  
High Density Lipoprotein Cholesterol ◽  
Ankle Brachial Index ◽  
Density Lipoprotein ◽  
High Density ◽  
Lipoprotein Cholesterol ◽  
Lipid Lowering ◽  
Cholesterol Ratio ◽  
Potential Biomarker

Background: The associations of triglyceride (TG) to high-density lipoprotein cholesterol ratio (HDL‑C) and total cholesterol (TC) to HDL‑C ratio and low ankle brachial index (ABI) were seldom investigated. Patients and methods: A population based cross-sectional survey was conducted and 2982 participants 60 years and over were recruited. TG, TC, HDL‑C, and low-density lipoprotein cholesterol (LDL-C) were assessed in all participants. Low ABI was defined as ABI ≤ 0.9 in either leg. Multiple logistic regression models were applied to study the association between TG/HDL‑C ratio, TC/HDL‑C ratio and low ABI. Results: The TG/HDL‑C ratios for those with ABI > 0.9 and ABI ≤ 0.9 were 1.28 ± 1.20 and 1.48 ± 1.13 (P < 0.0001), while the TC/HDL‑C ratios were 3.96 ± 1.09 and 4.32 ± 1.15 (P < 0.0001), respectively. After adjusting for age, gender, body mass index, obesity, current drinking, physical activity, hypertension, diabetes, lipid-lowering drugs, and cardiovascular disease history, the odds ratios (ORs) with 95 % confidence intervals (CIs) of low ABI for TG/HDL‑C ratio and TC/HDL‑C ratio were 1.10 (0.96, 1.26) and 1.34 (1.14, 1.59) in non-smokers. When TC was further adjusted, the ORs (95 % CIs) were 1.40 (0.79, 2.52) and 1.53 (1.21, 1.93) for TG/HDL‑C ratio and TC/HDL‑C ratio, respectively. Non-linear relationships were detected between TG/HDL‑C ratio and TC/HDL‑C ratio and low ABI in both smokers and non-smokers. Conclusions: TC/HDL‑C ratio was significantly associated with low ABI in non-smokers and the association was independent of TC, TG, HDL‑C, and LDL-C. TC/HDL‑C might be considered as a potential biomarker for early peripheral arterial disease screening.

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