Nonlinear feedback model attitude control using CCD in magnetic suspension system

A model attitude control system for a CCD camera magnetic suspension system is studied in this paper. In a recent work, a position and attitude sensing method was proposed. From this result, model position and attitude of a magnetic suspension system can be detected by generating digital outputs. Based on this achievement, a control system design using nonlinear feedback techniques for magnetic suspended model attitude control is proposed

Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1097

NGC 1097 is a nearby barred spiral galaxy believed to be interacting with the elliptical galaxy NGC 1097A located to its northwest. It hosts a Seyfert 1 nucleus surrounded by a circumnuclear starburst ring. Two straight dust lanes connected to the ring extend almost continuously out to the bar. The other ends of the dust lanes attach to two main spiral arms. To provide a physical understanding of its structural and kinematical properties, two-dimensional hydrodynamical simulations have been carried out. Numerical calculations reveal that many features of the gas morphology and kinematics can be reproduced provided that the gas flow is governed by a gravitational potential associated with a slowly rotating strong bar. By including the self-gravity of the gas disk in our calculation, we have found the starburst ring to be gravitationally unstable which is consistent with the observation in \citet{hsieh11}. Our simulations show that the gas inflow rate is 0.17 M_\sun yr$^{-1}$ into the region within the starburst ring even after its formation, leading to the coexistence of both a nuclear ring and a circumnuclear disk.Comment: 32 pages, 14 figures, 1 table, accepted for publication in the Ap

Magnetic Leviation System Design and Implementation for Wind Tunnel Application

This paper presents recent work in magnetic suspension wind tunnel development in National Cheng Kung University. In this phase of research, a control-based study is emphasized to implement a robust control system into the experimental system under study. A ten-coil 10 cm x 10 cm magnetic suspension wind tunnel is built using a set of quadrant detectors for six degree of freedom control. To achieve the attitude control of suspended model with different attitudes, a spacial electromagnetic field simulation using OPERA 3D is studied. A successful test for six degree of freedom control is demonstrated in this paper

Development of Dual Power Multirotor System

Vertical take-off and landing (VTOL) aircraft has good flight characteristics and system performance without runway. The multirotor system has been tried to expand into larger size for longer endurance or higher payload. But the motor power to endurance ratio has been limited. Due to the specific energy of gasoline being much higher than battery, introducing gasoline engine into multirotor system can be considered. This paper proposes a dual power multirotor system to combine a quadrotor using gasoline engines to provide major lift in shorter arm with another quadrotor using brushless DC motors to offer most controllable force with longer arm. System design, fabrication, and verification of the proposed dual power multirotor system development are presented. Preliminary flights have achieved 16 kg payload for long endurance flight. This is useful for various applications with advanced improvements

Dynamic Antenna Alignment Control in Microwave Air-Bridging for Sky-Net Mobile Communication Using Unmanned Flying Platform

This paper presents a preliminary study on establishing a mobile point-to-point (P2P) microwave air-bridging (MAB) between Unmanned Low Altitude Flying Platform (ULAFP) and backhaul telecommunication network. The proposed Sky-Net system relays telecom signal for general mobile cellphone users via ULAFP when natural disaster sweeps off Base Transceiver Stations (BTSs). Unlike the conventional fix point microwave bridging application, the ULAFP is cruising on a predefined mission flight path to cover a wider range of service. The difficulty and challenge fall on how to maintain antenna alignment accurately in order to provide the signal strength for MAB. A dual-axis rotation mechanism with embedded controller is designed and implemented on airborne and ground units for stabilizing airborne antenna and tracking the moving ULAFP. The MAB link is established in flight tests using the proposed antenna stabilizing/tracking mechanism with correlated control method. The result supports backbone technique of the Sky-Net mobile communication and verifies the feasibility of airborne e-Cell BTS

Ecophysiology and plant size in a tropical epiphytic fern, Asplenium nidus, in Taiwan

Recent studies indicate that, especially in epiphytes, plant size has a strong influence on the ecophysiology of individual leaves of a plant. Extensive data sets that address this phenomenon, however, are limited to a few taxa of flowering plants. It was the purpose of this study to examine numerous physiological parameters in individuals of varying sizes of Asplenium nidus, a widespread epiphytic tropical fern, in a rain forest in northeastern Taiwan. Although stomatal dimensions and frond thickness did not vary with plant size, frond stomatal densities were higher in larger plants. Frond elemental concentration did not vary with plant size for nitrogen, magnesium, phosphorus, and sodium, while the concentrations of carbon, calcium, and potassium changed with plant size, though in different ways. The osmotic concentration of liquid expressed from the fronds did not change with plant size, nor did chlorophyll concentrations and chlorophyll a/b ratio. Fronds excised from smaller plants contained more water yet lost water at lower rates in laboratory drying experiments. Although rates of net CO2 exchange of the fronds measured in situ in the field appeared to increase with plant size, this increase and other size-related differences in gas exchange parameters were not significant. Although some aspects of the ecophysiology of this epiphytic fern varied with changes in plant size, most physiological parameters did not. Thus, the results of this study lend only little support to past findings that plant size is an important consideration in ecophysiological studies of plants

Cytoplasmic polyadenylation and cytoplasmic polyadenylation element-dependent mRNA regulation are involved in Xenopus retinal axon development.

BACKGROUND: Translation in axons is required for growth cone chemotropic responses to many guidance cues. Although locally synthesized proteins are beginning to be identified, how specific mRNAs are selected for translation remains unclear. Control of poly(A) tail length by cytoplasmic polyadenylation element (CPE) binding protein 1 (CPEB1) is a conserved mechanism for mRNA-specific translational regulation that could be involved in regulating translation in axons. RESULTS: We show that cytoplasmic polyadenylation is required in Xenopus retinal ganglion cell (RGC) growth cones for translation-dependent, but not translation-independent, chemotropic responses in vitro, and that inhibition of CPE binding through dominant-negative interference severely reduces axon outgrowth in vivo. CPEB1 mRNA transcripts are present at low levels in RGCs but, surprisingly, CPEB1 protein was not detected in eye or brain tissue, and CPEB1 loss-of-function does not affect chemotropic responses or pathfinding in vivo. UV cross-linking experiments suggest that CPE-binding proteins other than CPEB1 in the retina regulate retinal axon development. CONCLUSION: These results indicate that cytoplasmic polyadenylation and CPE-mediated translational regulation are involved in retinal axon development, but that CPEB1 may not be the key regulator of polyadenylation in the developing retina.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

A Unified Approach to Nonlinear Dynamic Inversion Control with Parameter Determination by Eigenvalue Assignment

This paper presents a unified approach to nonlinear dynamic inversion control algorithm with the parameters for desired dynamics determined by using an eigenvalue assignment method, which may be applied in a very straightforward and convenient way. By using this method, it is not necessary to transform the nonlinear equations into linear equations by feedback linearization before beginning control designs. The applications of this method are not limited to affine nonlinear control systems or limited to minimum phase problems if the eigenvalues of error dynamics are carefully assigned so that the desired dynamics is stable. The control design by using this method is shown to be robust to modeling uncertainties. To validate the theory, the design of a UAV control system is presented as an example. Numerical simulations show the performance of the design to be quite remarkable

A new self-planning methodology based on signal quality and user traffic in Wi-Fi networks

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-030-19909-8_2Wi-Fi networks have become one of the most popular technologies for the provisioning of multimedia services. Due to the exponential increase in the number of Access Points (AP) in these networks, the automation of the planning, configuration, optimization and management tasks has become of prime importance. The efficiency of these automated processes can be improved with the inclusion of data analytics mechanisms able to process the large amount of data that can be collected from Wi-Fi networks by powerful monitoring systems. This paper presents a new self-planning methodology that collects historical network measurements and extracts knowledge about user signal quality and traffic demands to determine adequate AP relocations. The performance of the proposed AP relocation methodology based on a genetic algorithm is validated in a real Wi-Fi network. The proposed approach can be easily adapted to other contexts such as small cell networks.Peer ReviewedPostprint (author's final draft