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Journal articles on the topic 'Multi-steered'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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1

V, Amrutha Mohanan K., Hema E. K, and Monisree S. Audline Beena S. P. "Raspberry Pibot Manipulated with Skid-Steered Mechanism for Multi-Environment Surveillance." International Journal of Trend in Scientific Research and Development Volume-2, Issue-3 (April 30, 2018): 1483–91. http://dx.doi.org/10.31142/ijtsrd11240.

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2

Ljungqvist, Oskar, Kristoffer Bergman, and Daniel Axehill. "Optimization-based motion planning for multi-steered articulated vehicles." IFAC-PapersOnLine 53, no. 2 (2020): 15580–87. http://dx.doi.org/10.1016/j.ifacol.2020.12.2403.

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3

Backé, Guillaume, Ernest Swierczek, Justin MacDonald, Adam Bailey, David Tassone, Hani Abul Khair, Simon Holford, and Rosalind King. "Seismic attributes and structural interpretation—it takes two to tango..." APPEA Journal 52, no. 1 (2012): 437. http://dx.doi.org/10.1071/aj11035.

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In this paper, different 3D seismic attributes calculated to improve the accuracy and robustness of structural interpretations in several energy-rich Australian basins are compared. Detailed and precise fault and fracture maps are crucial not only for initial petroleum play assessment, but also for fault seal analysis and reservoir integrity studies. Robust fault and fracture models are also needed to improve the design of reservoir simulation programs and to manage the long-term containment of gas in geological formations. Different attributes (including coherency, dip-steered similarity, dip-steered median filter, dip-steered variance, apparent dip, and dip-steered most-positive and most-negative curvatures) from an array of 3D seismic datasets to better image structural fabrics, such as normal and different fractures patterns, in the North Perth, Cooper, Ceduna, Otway and Gippsland basins have been calculated. The results provide a remarkable improvement in the quality and precision of structural maps using this multi-attribute mapping workflow by comparison with more conventional maps produced, solely using seismic amplitude data. The key to the successful application of multi-attribute structural analysis, however, remains with the ability of the interpreter to identify meaningful structural information from a large volume of data. Thus, the structural expertise of the interpreter remains as the cornerstone to making geological sense of the various seismic processing techniques available.
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4

Orosco-Guerrero, R., E. Aranda-Bricaire, and M. Velasco-Villa. "GLOBAL PATH-TRACKING FOR A MULTI-STEERED GENERAL N-TRAILER." IFAC Proceedings Volumes 35, no. 1 (2002): 477–82. http://dx.doi.org/10.3182/20020721-6-es-1901.00241.

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Ljungqvist, Oskar, and Daniel Axehill. "A predictive path-following controller for multi-steered articulated vehicles." IFAC-PapersOnLine 53, no. 2 (2020): 15725–32. http://dx.doi.org/10.1016/j.ifacol.2020.12.053.

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6

Nabavizadeh, Alireza, Pengfei Song, Shigao Chen, James F. Greenleaf, and Matthew W. Urban. "Multi-source and multi-directional shear wave generation with intersecting steered ultrasound push beams." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 62, no. 4 (April 2015): 647–62. http://dx.doi.org/10.1109/tuffc.2014.006805.

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7

El-Hajjar, Mohammed, Osamah Alamri, Jin Wang, Salam Zummo, and Lajos Hanzo. "Layered steered space-time codes using multi-dimensional sphere packing modulation." IEEE Transactions on Wireless Communications 8, no. 7 (July 2009): 3335–40. http://dx.doi.org/10.1109/twc.2009.071292.

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8

Orosco-Guerrero, R., E. Aranda-Bricaire, and M. Velasco-Villa. "MODELING AND DYNAMIC FEEDBACK LINEARIZATION OF A MULTI-STEERED N-TRAILER." IFAC Proceedings Volumes 35, no. 1 (2002): 103–8. http://dx.doi.org/10.3182/20020721-6-es-1901.00267.

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9

Pereira, D. A., T. P. Sales, and D. A. Rade. "Multi-objective frequency and damping optimization of tow-steered composite laminates." Composite Structures 256 (January 2021): 112932. http://dx.doi.org/10.1016/j.compstruct.2020.112932.

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10

Lang, Wen Chang, Bai Zhong Wu, and Bin Gao. "Design of a Compact and Multi-Function Magnetic Field Steered Arc Source." Applied Mechanics and Materials 152-154 (January 2012): 1698–704. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.1698.

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Based on the principle of the control of magnetic field on arc spot motion, a compact and multi-function magnetic field steered arc source has been designed in this paper. The rotating magnetic field generator driven by small DC motors or AC motors has been also equipped behind the base of the target materials of magnetic field steered arc source. The magnet yoke fixed on shaft will be driven by the motors so as to promote the rotation of permanent magnets which are rationally distributed on magnet yoke. The different distribution of permanent magnets will produce the rotating magnetic field with different configuration structures and then the purpose of multi-control mode can be achieved. Meanwhile, the dynamic rotating magnetic field with different configurations have been also produced in this design through employing the simple and compact arc source as well as the permanent magnet with different distributions in order to improve the discharge form of arc spots, control the trajectory of arc spots, improve the utilization of target materials and the uniformity of etching as well as reduce or inhibit the emission of large particles. At the same time, the high-quality film can be also prepared so as to realize the arc spot control with various forms in an arc source, satisfy the different demands and expand the application of arc ion plating.
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11

Hemadeh, Ibrahim A., Mohammed El-Hajjar, Seunghwan Won, and Lajos Hanzo. "Layered Multi-Group Steered Space-Time Shift-Keying for Millimeter-Wave Communications." IEEE Access 4 (2016): 3708–18. http://dx.doi.org/10.1109/access.2016.2552078.

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12

Saikia, Riddhiman, and Deepak Sharma. "Reference-lines-steered memetic multi-objective evolutionary algorithm with adaptive termination criterion." Memetic Computing 13, no. 1 (February 14, 2021): 49–67. http://dx.doi.org/10.1007/s12293-021-00324-x.

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13

Li, Yun Hua, Li Man Yang, and Gui Lin Yang. "Coordinated Motion Control of Large-Scale Transporter for Conveying Heavy Frame Components in Ship-Manufacturing." Materials Science Forum 505-507 (January 2006): 1159–64. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.1159.

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A large-scale elevating transporter that has multi-wheels to be steered independently is a very complex mechatronic system. Aiming at its real-time coordinated motion control, a multi-mode steering system based on Networked Control System (NCS) is proposed to tackle the problem in the paper. Through motion synthesis, such as kinematics and dynamics modeling and analysis, and using the inherent real-time data sharing of the NCS, a cross-coupled control algorithm for improving contour accuracy is developed. This control methodology is then applied to the coordinated motion control of a practical product with multi-steering modes successfully.
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14

Ai, Huifang, Qianlong Kang, Wei Wang, Kai Guo, and Zhongyi Guo. "Multi-Beam Steering for 6G Communications Based on Graphene Metasurfaces." Sensors 21, no. 14 (July 13, 2021): 4784. http://dx.doi.org/10.3390/s21144784.

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As communication technology is entering the 6G era, a great demand for high-performance devices operating in the terahertz (THz) band has emerged. As an important part of 6G technology, indoor communication requires multi-beam steering and tracking to serve multi-users. In this paper, we have designed a graphene metasurface that can realize multi-beam steering for directional radiations. The designed metasurface consists of graphene ribbons, dielectric spacer, and metal substrate. By designing the graphene ribbons and controlling the applied voltage on them, we have obtained single-, double-, and triple-beam steering. In addition, we have also numerically calculated the far-field distributions of the steered multi-beam with a diffraction distance of 2 m. Our design has potential applications in future indoor directional 6G communications.
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15

Cao, Xiaohuan, Jianhua Yang, Yaozong Gao, Yanrong Guo, Guorong Wu, and Dinggang Shen. "Dual-core steered non-rigid registration for multi-modal images via bi-directional image synthesis." Medical Image Analysis 41 (October 2017): 18–31. http://dx.doi.org/10.1016/j.media.2017.05.004.

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16

Mane, Sunita V., and Uttam L. Bombale. "Robust and Efficient DOA-Steered Adaptive MVDR-FROST Beamforming Model for Multi-source Low SNR Environment." International Journal of Wireless Information Networks 28, no. 2 (February 24, 2021): 162–74. http://dx.doi.org/10.1007/s10776-021-00506-x.

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17

Hao, Jian Hua, Dian Fei Pan, and Nai Ping Cheng. "Occultation Judgment for the Hemispherical Coverage Multi-Planar Arrays Antenna." Applied Mechanics and Materials 513-517 (February 2014): 2663–67. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.2663.

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A flexible hemispherical coverage array antenna based on multi-planar arrays is proposed to meet the growing demands for multi-target TT&C. The advantages and disadvantages of multi-planar arrays and dome phased in engineering implement are compared. Meanwhile, the influence of different number of plane arrays on antenna pattern is analyzed. For the purpose of interference suppression a novel beamforming method by adding constraint conditions is analyzed to enhance the performance of antenna for TT&C system. Considering the influence of occultation effect on the antenna performance, an effective occultation algorithm is presented. Firstly, the faces in bright area are projected on the plane that is perpendicular with the direction of receiving wave. Secondly, adopting the principle of line segment intersection, the intersect relationship of projective planes is determined. Finally, the facets shadowing relationship is judged by the overlapping and depth-of-view of facets along the receiving wave direction. Theoretical analyses and simulation results show that the antenna has approximate uniform gain beampattern in different steered angle and the occultation algorithm is feasible and effective.
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18

Shi, Nuannuan, Ming Li, Ye Deng, Lihong Zhang, Shuqian Sun, Jian Tang, Wei Li, and Ninghua Zhu. "Experimental demonstration of a multi-target detection technique using an X-band optically steered phased array radar." Optics Express 24, no. 13 (June 17, 2016): 14438. http://dx.doi.org/10.1364/oe.24.014438.

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19

Hemadeh, Ibrahim A., Panagiotis Botsinis, Mohammed El-Hajjar, Seunghwan Won, and Lajos Hanzo. "Reduced-RF-Chain Aided Soft-Decision Multi-Set Steered Space-Time Shift-Keying for Millimeter-Wave Communications." IEEE Access 5 (2017): 7223–43. http://dx.doi.org/10.1109/access.2017.2694557.

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20

Yin, Yuming, Subhash Rakheja, and Paul-Emile Boileau. "Multi-performance analyses and design optimisation of hydro-pneumatic suspension system for an articulated frame-steered vehicle." Vehicle System Dynamics 57, no. 1 (March 27, 2018): 108–33. http://dx.doi.org/10.1080/00423114.2018.1453079.

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21

Daeglau, Mareike, Frank Wallhoff, Stefan Debener, Ignatius Condro, Cornelia Kranczioch, and Catharina Zich. "Challenge Accepted? Individual Performance Gains for Motor Imagery Practice with Humanoid Robotic EEG Neurofeedback." Sensors 20, no. 6 (March 14, 2020): 1620. http://dx.doi.org/10.3390/s20061620.

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Optimizing neurofeedback (NF) and brain–computer interface (BCI) implementations constitutes a challenge across many fields and has so far been addressed by, among others, advancing signal processing methods or predicting the user’s control ability from neurophysiological or psychological measures. In comparison, how context factors influence NF/BCI performance is largely unexplored. We here investigate whether a competitive multi-user condition leads to better NF/BCI performance than a single-user condition. We implemented a foot motor imagery (MI) NF with mobile electroencephalography (EEG). Twenty-five healthy, young participants steered a humanoid robot in a single-user condition and in a competitive multi-user race condition using a second humanoid robot and a pseudo competitor. NF was based on 8–30 Hz relative event-related desynchronization (ERD) over sensorimotor areas. There was no significant difference between the ERD during the competitive multi-user condition and the single-user condition but considerable inter-individual differences regarding which condition yielded a stronger ERD. Notably, the stronger condition could be predicted from the participants’ MI-induced ERD obtained before the NF blocks. Our findings may contribute to enhance the performance of NF/BCI implementations and highlight the necessity of individualizing context factors.
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22

Vargas-Quintero, Lorena, Boris Escalante-Ramírez, Lisbeth Camargo Marín, Mario Guzmán Huerta, Fernando Arámbula Cosio, and Héctor Borboa Olivares. "Left ventricle segmentation in fetal echocardiography using a multi-texture active appearance model based on the steered Hermite transform." Computer Methods and Programs in Biomedicine 137 (December 2016): 231–45. http://dx.doi.org/10.1016/j.cmpb.2016.09.021.

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23

Liu, Hang, Yi Li, and Rich S. Castle. "Enhancement of attosecond pulse in water window region by using pump-probe approach." International Journal of Modern Physics B 32, no. 29 (November 20, 2018): 1850318. http://dx.doi.org/10.1142/s0217979218503186.

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An effective scheme to enhance the harmonic yield and the attosecond (as) pulse signal from H[Formula: see text] has been proposed by using the pump-probe laser field. It is found that with the help of the multi-cycle pump pulse, H[Formula: see text] can be steered into the resonance ionization regions, where the ionization probability can be remarkably enhanced. Thus, the harmonic yield can be remarkably enhanced when a sequential mid-infrared probe pulse is added. Further, by modulating the phase of the probe pulse and by adding a controlling pulse, the harmonic cutoff can be extended up to the water window region. Finally, by the Fourier transformation of the selected harmonics on the harmonic supercontinuum, the water window attosecond pulses as short as 25 as can be obtained.
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24

Hirono, M., H. Luce, M. Yamamoto, and S. Fukao. "Horizontal maps of echo power in the lower stratosphere using the MU radar." Annales Geophysicae 22, no. 3 (March 19, 2004): 717–24. http://dx.doi.org/10.5194/angeo-22-717-2004.

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Abstract. In recent works, zenithal and azimuthal angle variations of echo power measured by VHF Stratosphere-Troposphere (ST) radars have been analyzed in detail using different radar multi-beam configurations. It was found that the azimuthal angle corresponding to maximum echo power is closely related to the direction of the horizontal wind shear. These properties indicate that local wind shear affects the tilt of the scatterers. Moreover, horizontal maps of echo power collected using a large set of beams steered pulse-to-pulse up to 40 degrees off zenith revealed that the power distribution pattern in the troposphere is often skewed. In this work, a three-dimensional description of echo power variations up to 24 degrees off zenith is shown for measurements in the lower stratosphere (i.e. up to approximately 20km) using a "sequential multi-beam" (SMB) configuration. Such a description was not possible above the tropopause with classical multi-beam configurations because of the loss of radar sensitivity due to the limited integration time by the use of a large number of beams. This work attempts to complete previous descriptions of the phenomenon by some observations in the lower stratosphere discussed in association with complementary balloon measurements. Key words. Meteorology and atmospheric dynamics (turbulence) – Radio Science (remote sensing)
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25

Ashraf, Umar, Hucai Zhang, Aqsa Anees, Hassan Nasir Mangi, Muhammad Ali, Zaheen Ullah, and Xiaonan Zhang. "Application of Unconventional Seismic Attributes and Unsupervised Machine Learning for the Identification of Fault and Fracture Network." Applied Sciences 10, no. 11 (June 2, 2020): 3864. http://dx.doi.org/10.3390/app10113864.

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The identification of small scale faults (SSFs) and fractures provides an improved understanding of geologic structural features and can be exploited for future drilling prospects. Conventional SSF and fracture characterization are challenging and time-consuming. Thus, the current study was conducted with the following aims: (a) to provide an effective way of utilizing the seismic data in the absence of image logs and cores for characterizing SSFs and fractures; (b) to present an unconventional way of data conditioning using geostatistical and structural filtering; (c) to provide an advanced workflow through multi-attributes, neural networks, and ant-colony optimization (ACO) for the recognition of fracture networks; and (d) to identify the fault and fracture orientation parameters within the study area. Initially, a steering cube was generated, and a dip-steered median filter (DSMF), a dip-steered diffusion filter (DSDF), and a fault enhancement filter (FEF) were applied to sharpen the discontinuities. Multiple structural attributes were applied and shortlisted, including dip and curvature attributes, filtered and unfiltered similarity attributes, thinned fault likelihood (TFL), fracture density, and fracture proximity. These shortlisted attributes were computed through unsupervised vector quantization (UVQ) neural networks. The results of the UVQ revealed the orientations, locations, and extensions of fractures in the study area. The ACO proved helpful in identifying the fracture parameters such as fracture length, dip angle, azimuth, and surface area. The adopted workflow also revealed a small scale fault which had an NNW–SSE orientation with minor heave and throw. The implemented workflow of structural interpretation is helpful for the field development of the study area and can be applied worldwide in carbonate, sand, coal, and shale gas fields.
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Abul Khair, Hani, Guillaume Backé, Rosalind King, Simon Holford, Mark Tingay, Dennis Cooke, and Martin Hand. "Factors influencing fractures networks within Permian shale intervals in the Cooper Basin, South Australia." APPEA Journal 52, no. 1 (2012): 213. http://dx.doi.org/10.1071/aj11016.

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The future success of both enhanced (engineered) geothermal systems and shale gas production is reliant on the development of reservoir stimulation strategies that suit the local geo-mechanical conditions of the prospects. The orientation and nature of the in-situ stress field and pre-existing natural fracture networks in the reservoir are among the critical parameters that will control the quality of the stimulation program. This study provides a detailed investigation into the nature and origin of natural fractures in the area covered by the Moomba–Big Lake 3D seismic survey, in the southwest termination of the Nappamerri Trough of the Cooper Basin. These fractures are imaged by both borehole image logs and complex multi-traces seismic attributes (e.g. dip-steered most positive curvature and dip-steered similarity), are pervasive throughout the cube, and exhibit a relatively consistent northwest–southeast orientation. Horizon extraction of the seismic attributes reveal a strong variation in the spatial distribution of the fractures. In the acreage of interest, fracture density is at its highest in the vicinity of faults and on top of tight antiforms. This study also suggests a good correlation between high fracture density and high gamma ray values. The correlation between high fracture density and shale content is somewhat counterintuitive, as shale is expected to have a higher tensile and compressive strengths at shallow depths and typically contain fewer fractures (Lin, 1983). At large depths, however—and due to sandstone diagenesis and cementation—shale has lower tensile and compressive strength than sandstone and is expected to be more fractured (Lin, 1983). A similar correlation has been noted in other Australian Basins (e.g. Northern Perth Basin). Diagenetic effects, pore pressure, stiffness, variations in tensile versus compressive strength of the shale and the sandstone may explain this disparity.
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27

Chen, Hao, Chengju Liu, and Qijun Chen. "Efficient and robust approaches for three-dimensional sound source recognition and localization using humanoid robots sensor arrays." International Journal of Advanced Robotic Systems 17, no. 4 (July 1, 2020): 172988142094135. http://dx.doi.org/10.1177/1729881420941357.

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Efficient and robust sound source recognition and localization is one of the basic techniques for humanoid robots in terms of reaction to environments. Due to the fixed sensor arrays and limited computation resources in humanoid robots, there comes challenge for sound source recognition and localization. This article proposes a sound source recognition and localization framework to realize real-time and precise sound source recognition and localization system using humanoid robots’ sensor arrays. The type of the audio is recognized according to the cross-correlation function. And steered response power-phase transform function in discrete angle space is used to search the sound source direction. The sound source recognition and localization framework presents a new multi-robots collaboration system to get the precise three-dimensional sound source position and introduces a distance weighting revision way to optimize the localization performance. Additionally, the experiment results carried out on humanoid robot NAO demonstrate that the proposed approaches can recognize and localize the sound source efficiently and robustly.
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28

Rouhi, Mohammad, Hossein Ghayoor, Suong V. Hoa, and Mehdi Hojjati. "The effect of the percentage of steered plies on the bending-induced buckling performance of a variable stiffness composite cylinder." Science and Engineering of Composite Materials 22, no. 2 (March 1, 2015): 149–56. http://dx.doi.org/10.1515/secm-2014-0258.

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AbstractThe fiber steering capability of automated fiber placement machines offers the designers more room to fully exploit the directional properties of composite materials. Circumferential stiffness tailoring by fiber steering can considerably increase the bending-induced buckling performance of laminated composite cylinders. The potential structural improvement resulting from fiber steering depends on different design parameters such as the number of plies considered for fiber steering in a laminate. In this study, the buckling performance improvement of a variable stiffness (VS) composite cylinder is investigated for different percentages of plies considered for fiber steering in a multilayered composite laminate. A surrogate-based modeling along with a multi-step optimization is used in the design procedure of this study. The improvements in the buckling performance are shown and verified using finite element analysis in ABAQUS software. The mechanisms leading to buckling performance improvement of VS composites are also investigated and presented for different percentages of fiber-steered plies.
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29

Britton, Joanne. "Being an insider and outsider: whiteness as a key dimension of difference." Qualitative Research 20, no. 3 (September 12, 2019): 340–54. http://dx.doi.org/10.1177/1468794119874599.

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This article demonstrates the significance of engaging with whiteness as a key dimension of difference shaping research in multi-faceted ways. I critically reflect on a research project that included interviews with Muslim men in Rotherham, a northern English town that had experienced a child sexual exploitation crisis involving Pakistani Muslim men. It raised significant methodological and epistemological issues regarding my position in the research, as a white female researcher, and my relationships with local Pakistani Muslim men and women. I highlight the fluidity of my insider–outsider position through exploring political and ethical dilemmas involved in carrying out the research and structural and experiential aspects of researcher subjectivity. I show how being white both facilitated and obstructed the research as I steered my way through a highly sensitive set of circumstances and how engaging with whiteness is key in democratising research and shedding light on unequal power relations in knowledge production.
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30

MAGGETTI, Martino. "Trust, Coordination and Multi-level Arrangements: Lessons for a European Health Union." European Journal of Risk Regulation 11, no. 4 (November 12, 2020): 790–99. http://dx.doi.org/10.1017/err.2020.97.

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In the wake of the outbreak of the COVID-19 crisis, the Swedish and Swiss governments adopted a similar policy approach. They enacted mostly non-binding measures to contain the epidemic, relying on the high level of interpersonal trust and trust in political institutions that exist in both of these (broadly comparable) countries to ensure compliance. However, unlike Sweden’s strategy, the Swiss policy response evolved during the early weeks of the “first wave”, achieving public health and socioeconomic results that have been considered as satisfactory, notwithstanding the complex institutional setting and policy process, the central location of Switzerland in continental Europe, its openness and its closeness with deeply affected regions in Italy and France. To shed light on this policy response and to draw lessons from it, this paper firstly discusses the role played by the new Swiss Epidemics Act. This law centralises decision-making capacity at the federal level and expands the competences of the central government, while leaving leeway to subnational units for implementation and recognising the need for increased international regulatory cooperation. Secondly, it shows how such a solution – a multi-level arrangement steered from the federal level with quite strong vertical and horizontal coordination mechanisms – could work as a blueprint for a European Health Union.
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31

Scharf, Nadine, Thomas Wachtel, Suhana Reddy, and Ina Säumel. "Urban Commons for the Edible City—First Insights for Future Sustainable Urban Food Systems from Berlin, Germany." Sustainability 11, no. 4 (February 14, 2019): 966. http://dx.doi.org/10.3390/su11040966.

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Urban planning is facing multi-layered challenges to manage the transformation towards a more sustainable and inclusive society. The recently evolved concept of an “urban commons” responds to the crucial need to re-situate residents as key actors. Urban food commons summarize all initiatives that are food-related (e.g., cultivation, harvest, and distribution), aiming at a visualization and utilization of value chains and the commons-based linkage between them. We explored first insights of food commons in Berlin based on semi-structured, in-depth interviews. Urban food commons strengthen identification, participation, self-organization, and social resilience, are steered by bottom-up processes, and can be a powerful tool for a transformation towards urban sustainability. However, a viable political integration of existing initiatives lacks due to structural implementation problems. Respondents recommend a pooling of all initiatives in a strong network and a mediation interface to coordinate between food commons and city administration and politics. A combined approach of commons and edible cities will be helpful for the development of future prove food systems.
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32

Spyrou, K. J. "Dynamic Instability in Quartering Seas—Part III: Nonlinear Effects on Periodic Motions." Journal of Ship Research 41, no. 03 (September 1, 1997): 210–23. http://dx.doi.org/10.5957/jsr.1997.41.3.210.

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The loss of stability of the horizontal-plane periodic motion of a steered ship in waves is investigated. In earlier reports we referred to the possibility of a broaching mechanism that will be intrinsic to the periodic mode, whereby there will exist no need for the ship to go through the surf-riding stage. However, about this point the discussion was essentially conjectural. In order to provide substance we present here a theoretical approach that is organized in two stages: Initially, we demonstrate the existence of a mechanism of parametric instability of yaw on the basis of a rudimentary, single-degree model of maneuvering motion in waves. Then, with a more elaborate model, we identify the underlying nonlinear phenomena that govern the large-amplitude horizontal ship motions, considering the ship as a multi-degree, nonlinear oscillator. Our analysis brings to light a very specific sequence of phenomena leading to cumulative broaching that involves a change in the stability of the ordinary periodic motion on the horizontal plane, a transition towards subharmonic response and, ultimately, a sudden jump to resonance. Possible means for controlling the onset of such undesirable behavior are also investigated.
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33

Mohammad, Tarek, Siyuan He, and Ridha Ben Mrad. "Analysis of Optical Diffraction Profiles Created by Phase-Modulating MEMS Micromirror Arrays." Micromachines 12, no. 8 (July 28, 2021): 891. http://dx.doi.org/10.3390/mi12080891.

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This paper presents modeling and analysis of light diffraction and light-intensity modulation performed by an optical phased array (OPA) system based on metal-coated silicon micromirrors. The models can be used in the design process of a microelectromechanical system (MEMS)-based OPA device to predict its optical performance in terms of its field of view, response, angular resolution, and long-range transmission. Numerical results are derived using an extended model for the 1st-order diffracted light intensity modulation due to phase shift. The estimations of the optical characteristics are utilized in the designs of an OPA system capable of active phase modulation and an OPA system capable of array pitch tuning. Both designs are realized using the Multi-User MEMS Processes (PolyMUMPs) in which polysilicon is used as structural material for the MEMS-actuated mirrors. The experiments are performed to evaluate the optical performance of the prototypes. The tests show that the individually actuated micromirrors, which act as phase shifters, can transmit the most optical power along the 1st-order diffracted beam by actively changing their out-of-plane positions. In addition, the 1st-order diffracted beam with high optical intensity can be steered for distance measurement.
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34

Ali, Awaz, Aimee Sakes, Ewout A. Arkenbout, Paul Henselmans, Remi van Starkenburg, Tamas Szili-Torok, and Paul Breedveld. "Catheter steering in interventional cardiology: Mechanical analysis and novel solution." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 233, no. 12 (October 3, 2019): 1207–18. http://dx.doi.org/10.1177/0954411919877709.

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In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. Mechanically actuated steerable catheters appear the most in the clinical setting; however, they are bound to a number of mechanical limitations. The aim of this research is to gain insight in these limitations and use this information to develop a new prototype of a catheter with increased steerability. The main limitations in mechanically steerable catheters are identified and analysed, after which requirements and solutions are defined to design a multi-steerable catheter. Finally, a prototype is built and a proof-of-concept test is carried out to analyse the steering functions. The mechanical analysis results in the identification of five limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, (4) coupled tip-shaft movements, and (5) complex cardiac environment. Solutions are found to each of the limitations and result in the design of a novel multi-steerable catheter with four degrees of freedom. A prototype is developed which allows the dual-segmented tip to be steered over multiple planes and in multiple directions, allowing a range of complex motions including S-shaped curves and circular movements. A detailed analysis of limitations underlying mechanically steerable catheters has led to a new design for a multi-steerable catheter for complex cardiac interventions. The four integrated degrees of freedom provide a high variability of tip directions, and repetition of the bending angle is relatively simple and reliable. The ability to steer inside the heart with a variety of complex shaped curves may potentially change conventional approaches in interventional cardiology towards more patient-specific and lower complexity procedures. Future directions are headed towards further design optimizations and the experimental validation of the prototype.
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Malongo, Kenneth Iloka, Stephen Muathe, and Stephen Titus Waithaka. "The Moderating Effect of Organizational Characteristics on The Relationship Between Information Technology Integration and Performance: Empirical Evidence from Selected Public Hospitals in Kenya." INTERNATIONAL JOURNAL OF MANAGEMENT & INFORMATION TECHNOLOGY 14 (September 14, 2019): 3359–67. http://dx.doi.org/10.24297/ijmit.v15i0.8429.

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With the continuing digital revolution steered by the Internet, organizations are moving towards information technology integration to improve their performance. Regrettably, these developments have in no way been all-inclusive. The health gap between public institutions in first, second and third world nations has broadened. Public organizations in second and third world nations are characterized by poor performance. This study sought to establish the moderating effect of organizational characteristics on the relationship between information technology and performance of public hospitals in Kenya. The study used Technology Organization Environment (TOE) theory. The study was guided by explanatory and cross-sectional research design. The target population was 98 public hospitals in Kenya. Multi-stage sampling technique was used to select a sample size of 294 respondents. Primary data was collected using semi-structured questionnaires. For data analysis, descriptive statistics and multiple regression analyses were used. The study results established that organizational characteristics moderated the relationship between information technology integration and performance of public hospitals in Kenya. Therefore, study concluded that organizational characteristics play a major role in an organization’s adoption and utilization of information technology integration. The study recommends technologies should be customized to fit the type of organizational characteristics for better performance.
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Hausknost, Daniel, and Willi Haas. "The Politics of Selection: Towards a Transformative Model of Environmental Innovation." Sustainability 11, no. 2 (January 18, 2019): 506. http://dx.doi.org/10.3390/su11020506.

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As a purposive sustainability transition requires environmental innovation and innovation policy, we discuss potentials and limitations of three dominant strands of literature in this field, namely the multi-level perspective on socio-technical transitions (MLP), the innovation systems approach (IS), and the long-wave theory of techno-economic paradigm shifts (LWT). All three are epistemologically rooted in an evolutionary understanding of socio-technical change. While these approaches are appropriate to understand market-driven processes of change, they may be deficient as analytical tools for exploring and designing processes of purposive societal transformation. In particular, we argue that the evolutionary mechanism of selection is the key to introducing the strong directionality required for purposive transformative change. In all three innovation theories, we find that the prime selection environment is constituted by the market and, thus, normative societal goals like sustainability are sidelined. Consequently, selection is depoliticised and neither strong directionality nor incumbent regime destabilisation are societally steered. Finally, we offer an analytical framework that builds upon a more political conception of selection and retention and calls for new political institutions to make normatively guided selections. Institutions for transformative innovation need to improve the capacities of complex societies to make binding decisions in politically contested fields.
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Hayir, Celal, and Ayman Kole. "Cinematic Search for Identity in the Shade of Turkey’s 1960 Coup: The Social Realism Debate and The Hope." BORDER CROSSING 6, no. 1 (June 13, 2017): 153–68. http://dx.doi.org/10.33182/bc.v7i1.483.

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When the Turkish army seized power on May 27th, 1960, a new democratic constitution was carried into effect. The positive atmosphere created by the 1961 constitution quickly showed its effects on political balances in the parliament and it became difficult for one single party to come into power, which strengthened the multi-party-system. The freedom initiative created by 1961’s constitution had a direct effect on the rise of public opposition. Filmmakers, who generally steered clear from the discussion of social problems and conflicts until 1960, started to produce movies questioning conflicts in political, social and cultural life for the first time and discussions about the “Social Realism” movement in the ensuing films arose in cinematic circles in Turkey. At the same time, the “regional managers” emerged, and movies in line with demands of this system started to be produced. The Hope (Umut), produced by Yılmaz Güney in 1970, rang in a new era in Turkish cinema, because it differed from other movies previously made in its cinematic language, expression, and use of actors and settings. The aim of this study is to mention the reality discussions in Turkish cinema and outline the political facts which initiated this expression leading up to the film Umut (The Hope, directed by Yılmaz Güney), which has been accepted as the most distinctive social realist movie in Turkey.
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Carpenter, Chris. "First Multistage Fracturing of a Horizontal Well Drilled in a Tight Carbonate Reservoir in UAE." Journal of Petroleum Technology 73, no. 06 (June 1, 2021): 58–59. http://dx.doi.org/10.2118/0621-0058-jpt.

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203226, “First Multistage Fracturing of Horizontal Well Drilled in a Conventional Tight Carbonate Reservoir in an Onshore Field in the UAE: Challenges and Lessons Learned,” by Muhammad Aftab, SPE, Noor Talib, and Maad Subaihi, ADNOC, et al., prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. The reservoir upon which this case study is focused is a tight, low-permeability carbonate reservoir with thin layers. The objective of the field case was to increase and sustain productivity of a pilot well consisting of an openhole completion. The complete paper summarizes the design processes, selection criteria, challenges, and lessons learned during design and execution phases. The study may provide a potential approach for selecting the proper hydraulic fracturing method and technique in similar cases. Introduction Reservoir X is divided into six layers. Layers X-3 through X-6 have reasonable porosity development; valid pressure points exist in X-3 and X-6. Pumpout was performed while collecting samples from X-3 and X-6, followed by short buildups. Production-logging-tool measurement was performed and found two major oil-producing layers across X-3 (60% of total production) and X-6 (40% of total production). The remaining intervals of the perforation were almost inactive. Petrophyscial and testing results of vertical Well A resulted in a decision to drill a horizontal oil producer (Well B) through Layer X-3. Well B was steered with a 2,220-ft horizontal length, out of which 1,930 ft was inside X-3 and 290 ft were above X-3 be-cause of a fault throw of 16 ft true vertical depth. The well was steered with a horizontal length of 2,080 ft in X-6. Well B was completed with a 3½-in. completion and horizontal section as an openhole. Matrix stimulation using coiled tubing was performed with 15% hydrochloric acid in Well B. The well ceased to flow after 2 weeks of declining production. Rapid pressure depletion was observed in Well B. Localized depletion around the wellbore was anticipated because of poor matrix/matrix connectivity. After comprehensive studies and risk assessments, the decision was made to recomplete Well B with a cemented fracturing string to perform hydraulic fracturing with the plug-and-perf technique. This technique will allow flexibility of stage count and stage spacing and a multi-cluster design to maximize the stimulated reservoir volume (SRV) along the upper, middle, and lower layers. In addition, the operator and service provider collaborated to enhance this design through a zero-overflush technique with diverting agents. The complete paper provides a detailed discussion of the core measurement and 1D mechanical Earth model used in the hydraulic fracturing design. Hydraulic Fracturing Design The main challenge in fracturing Well B was to ensure that the fracture generated is contained within the reservoir. Well B is completed in two layers (X-3 and X-6). The bottom part of the well is in X-6 and close to another underlying reservoir (Fig. 1).
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Bostenaru Dan, M. D. "Review of retrofit strategies decision system in historic perspective." Natural Hazards and Earth System Sciences 4, no. 3 (June 25, 2004): 449–62. http://dx.doi.org/10.5194/nhess-4-449-2004.

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Abstract. Urban development is a process. In structuring and developing its phases different actors are implied, who act under different, sometimes opposite, dynamic conditions and within different reference systems. This paper aims to explore the contribution of participatism to disaster mitigation, when this concerns earthquake impact on urban settlements, through the support provided to multi-criteria decision in matters of retrofit. The research broadness in field of decision making on one side and the lack of a specific model for the retrofit of existing buildings on another side led to an extensive review of the state of the art in related models to address the issue. Core idea in the selection of existing models has been the preoccupation for collaborative issues, in other words, the consideration for the different actors implied in the planning process. The historic perspective on participative planning models is made from the view of two generations of citizen implication. The first approaches focus on the participation of the building owner/inhabitant in the planning process of building construction. As current strategies building rehabilitation and selection from alternative retrofit strategies are presented. New developments include innovative models using the internet or spatial databases. The investigated participation approaches show, that participation and communication as a more comprehensive term are an old topic in the field politics-democratisation-urbanism. In all cases it can be talked of "successful learning processes", of the improvement of the level of the professional debate. More than 30 years history of participation marked a transition in understanding the concept: from participation, based on a central decision process leading to a solution controlled and steered by the political-administrative system, to communication, characterised by simultaneous decision processes taking place outside politics and administration in co-operative procedures.
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Munoz-Martin, Joan Francesc, Raul Onrubia, Daniel Pascual, Hyuk Park, Adriano Camps, Christoph Rüdiger, Jeffrey Walker, and Alessandra Monerris. "Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications." Remote Sensing 12, no. 7 (April 9, 2020): 1208. http://dx.doi.org/10.3390/rs12071208.

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As opposed to monostatic radars where incoherent backscattering dominates, in bistatic radars, such as Global Navigation Satellite Systems Reflectometry (GNSS-R), the forward scattered signals exhibit both an incoherent and a coherent component. Current models assume that either one or the other are dominant, and the calibration and geophysical parameter retrieval (e.g., wind speed, soil moisture, etc.) are developed accordingly. Even the presence of the coherent component of a GNSS reflected signal itself has been a matter of discussion in the last years. In this work, a method developed to separate the leakage of the direct signal in the reflected one is applied to a data set of GNSS-R signals collected over the ocean by the Microwave Interferometer Reflectometer (MIR) instrument, an airborne dual-band (L1/E1 and L5/E5a), multi-constellation (GPS and Galileo) GNSS-R instrument with two 19-elements antenna arrays with 4 beam-steered each. The presented results demonstrate the feasibility of the proposed technique to untangle the coherent and incoherent components from the total power waveform in GNSS reflected signals. This technique allows the processing of these components separately, which increases the calibration accuracy (as today both are mixed and processed together), allowing higher resolution applications since the spatial resolution of the coherent component is determined by the size of the first Fresnel zone (300–500 meters from a LEO satellite), and not by the size of the glistening zone (25 km from a LEO satellite). The identification of the coherent component enhances also the location of the specular reflection point by determining the peak maximum from this coherent component rather than the point of maximum derivative of the incoherent one, which is normally noisy and it is blurred by all the glistening zone contributions.
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Malinovsky, M. P. "Development of a geometric slip flat model when turning a vehicle with two steering axles." Trudy NAMI, no. 2 (July 17, 2021): 34–45. http://dx.doi.org/10.51187/0135-3152-2021-2-34-45.

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Introduction (problem statement and relevance). One of the main stages in the design ofspecial purpose vehicles is the calculation of the steering control. At that, engineers are guided by anumber of regulatory documents that lack one of the most important requirements, which is to minimize tire lateral deviation. The author notes the lack of scientific research in the field of geometric slip, which is caused by the non-compliance between the actual angles of wheels rotation and the calculated values for pure rolling and is an inherent property of any traditional steering linkage.The purpose of the study was to develop a mathematical model of the steering drive of a special-purpose vehicle with two steering axles to assess the geometric and power slip.Methodology and research methods. There is a known method for calculating the steering drive using trigonometric expressions, in particular the cosine theorem. The author proposed to use the coordinateiterative method developed by him and based on the equation of the sphere, with the steering wheel rotation angle in the kinematic calculation of the steering drive as a differentiation step. The choice of the steering drive parameters according to the conditions of symmetry and minimization of slip was carried out by the method of multivariable optimization.Results. In the course of the research, it was found that the choice of the characteristic of geometric noncompliance was a multi-parameter task, and changing one parameter led to the necessity of adjusting the others. If it was not possible to achieve zero geometric slip for all steered wheels, the task of optimizing the steering drive parameters wasreduced to minimizing geometric or total slip. The value of the slip essentially depended on the selected differentiation step. When choosing the characteristic of geometric slip, it was necessary to observe the condition of the steering linkage symmetry when turning left and right. When the wheels were turned from the neutral position to the periphery, the power and geometric slip compensated each other, which led to the decrease of the total slip and tire wear.The scientific novelty of the work lies in the development of a geometric slip model for a vehicle with two steerable axles, including a spatial model of the steering drive which allows to evaluate the influence of the geometric slip on the turn kinematics, as well as the mutual influence of geometric and power slip in order to select the steering drive optimal parameters of the multi-axle vehicle from the viewpoint of minimizing tire wear during curvilinear motion.Practical significance. The research results must be taken into account in the development of steering drive and turning control systems for multi-axle special-purpose vehicles, including them in the educational process as well.
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42

Gorelov, V. A., K. B. Yevseyev, O. I. Chudakov, and K. S. Balkovskiy. "Evaluation of indicators of curvilinear movement of a road train using mathematical simulation." Izvestia MGTU MAMI 1, no. 4 (2020): 2–15. http://dx.doi.org/10.31992/2074-0530-2020-46-4-2-15.

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Introduction: a widespread approach to the transportation of large-sized and heavy-weight indi-visible cargo on roads and terrain is the use of multi-axle wheeled transport complexes, which are road trains. At the same time, due to the significant overall dimensions, one of the most important properties of such machines is agility, that is, the ability to move along a trajectory of large curvature in a limited area, which is especially important in loading / unloading zones. Subject of research: the article presents an approach to predicting the indicators of curvilinear movement of multi-axle wheeled road trains, based on the application of the method of mathemati-cal modeling of the dynamics of body systems. Methodology and methods: the essence of the method is to create a mathematical model of the movement of a road train, represented by a system of rigid bodies, which are interconnected by kin-ematic and power connections. The simulation model developed within the framework of the study makes it possible to take into account with high accuracy the peculiarities of the interaction of the wheel propeller with the supporting surface, the redistribution of normal reactions between the sup-port modules, as well as the force factors arising in the coupling device and ensuring the interaction between the tractive vehicle and the trailer link. The mathematical description of the interaction of the propeller with the ground is based on the concept of “friction ellipse”. Using the presented mod-el, an assessment of the turnability of a wheeled road train equipped with a trailed link with swivel and non-swivel wheels was carried out. The required width along the tracks of the outer (running in) and inner (lagging) wheels was used as an assessment criterion. To assess the feasibility of using a trailed link with fully steered wheels and, accordingly, complicating the design of the machine, an additional assessment of the required power of the steering drive was carried out. Results and scientific novelty: a mathematical model of the dynamics of a road train was de-veloped. It makes possible to predict with high accuracy the indicators of curvilinear movement of wheeled vehicles, as well as to estimate the required power of the steering drive. Practical significance: a mathematical model of road train movement was developed, which al-lows a wide range of tests to be carried out to assess not only the indicators of curved-linear move-ment, but also the mobility of wheeled vehicles of any configuration as a whole.
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43

Nguyen, Hung Q., Jim S. Whittington, John C. Devlin, Ha L. Vu, Ngoc-Vinh Vu, and Eddie Custovic. "Accurate Phase Calibration for Digital Beam-Forming in Multi-Transceiver HF Radar System." International Journal of Electronics and Telecommunications 59, no. 3 (September 1, 2013): 245–54. http://dx.doi.org/10.2478/eletel-2013-0029.

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Abstract The TIGER-3 radar is being developed as an “all digital” radar with 20 integrated digital transceivers, each connected to a separate antenna. Using phased array antenna techniques, radiated power is steered towards a desired direction based on the relative phases within the array elements. This paper proposes an accurate phase measurement method to calibrate the phases of the radio output signals using Field Programmable Gate Array (FPGA) technology. The method sequentially measures the phase offset between the RF signal generated by each transceiver and a reference signal operated at the same frequency. Accordingly, the transceiver adjusts its phase in order to align to the reference phase. This results in accurately aligned phases of the RF output signals and with the further addition of appropriate phase offsets, digital beamforming (DBF) can be performed steering the beam in a desired direction. The proposed method is implemented on a Virtex-5 VFX70T device. Experimental results show that the calibration accuracy is of 0.153 degrees with 14 MHz operating frequency.
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Zhang, Chao, Quanzhong Zhan, Qi Wang, Haichao Wu, Ting He, and Yi An. "Autonomous Dam Surveillance Robot System Based on Multi-Sensor Fusion." Sensors 20, no. 4 (February 17, 2020): 1097. http://dx.doi.org/10.3390/s20041097.

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Dams are important engineering facilities in the water conservancy industry. They have many functions, such as flood control, electric power generation, irrigation, water supply, shipping, etc. Therefore, their long-term safety is crucial to operational stability. Because of the complexity of the dam environment, robots with various kinds of sensors are a good choice to replace humans to perform a surveillance job. In this paper, an autonomous system design is proposed for dam ground surveillance robots, which includes general solution, electromechanical layout, sensors scheme, and navigation method. A strong and agile skid-steered mobile robot body platform is designed and created, which can be controlled accurately based on an MCU and an onboard IMU. A novel low-cost LiDAR is adopted for odometry estimation. To realize more robust localization results, two Kalman filter loops are used with the robot kinematic model to fuse wheel encoder, IMU, LiDAR odometry, and a low-cost GNSS receiver data. Besides, a recognition network based on YOLO v3 is deployed to realize real-time recognition of cracks and people during surveillance. As a system, by connecting the robot, the cloud server and the users with IOT technology, the proposed solution could be more robust and practical.
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Algorri, Jose Francisco, Virginia Urruchi, Noureddine Bennis, and Jose Manuel Sanchez-Pena. "Theoretical approach of a polymer stabilized blue phase beam steering." Photonics Letters of Poland 9, no. 1 (March 31, 2017): 14. http://dx.doi.org/10.4302/plp.v9i1.705.

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Nematic liquid crystal (LC)-based beam steering has been reported for wide applications. However, for conventional nematic LC beam steering the thickness is of several microns in order to have a wider deflection angle. The response time is relatively slow and the diffraction efficiency is low. In this work, novel beam steering based on polymer stabilized blue phase liquid crystal (PS-BPLC) has been designed and theoretically analyzed. This special mesophase of the chiral doped nematic LC has several advantageous characteristics, for example no need for alignment layers, microsecond response time and an isotropic voltage-off state. The results reveal control over phase retardation. The direction of the steered beam can be tuned by voltage. Depending on voltage configuration, either diffractive beam steering (0.5deg deviation for 1st order) or a tunable continuous phase (tunable deviation of 0.002deg) can be obtained. In the first case, the deflection angle could be tuned by stacks of samples. The second option has the same phase shift for the TE and TM modes so unpolarized light could be used. Full Text: PDF ReferencesF. Feng, I. White, T. Wilkinson, "Free Space Communications With Beam Steering a Two-Electrode Tapered Laser Diode Using Liquid-Crystal SLM", J. Lightwave Technol. 31, 2001 (2013). CrossRef E. Oton, J. Perez-Fernandez, D. Lopez-Molina, X. Quintana, J.M. Oton, M.A. Geday, "Reliability of Liquid Crystals in Space Photonics", IEEE Photonics Journal 7, 1 (2015). CrossRef J. Stockley, S. Serati, "Multi-access laser terminal using liquid crystal beam steering", IEEE in Aerospace Conference, 1972 (2005). CrossRef D. Zografopoulos and E. Kriezis, "Switchable beam steering with zenithal bistable liquid-crystal blazed gratings", Opt. Lett. 39, 5842 (2014). CrossRef Benedikt Scherger, et al., "Discrete Terahertz Beam Steering with an Electrically Controlled Liquid Crystal Device", J. Infrared. Millim. Terahertz Waves 33, 1117 (2012). CrossRef M.A. Geday, X. Quintana, E. Otón, B. Cerrolaza, D. Lopez, F. Garcia de Quiro, I. Manolis, A. Short, Proc. ICSO, Rhodes, Greece, pp. 1-4 (2010). CrossRef Y. Chen, S.-T. Wu, "The outlook for blue-phase LCDs", Proc. SPIE 9005, Advances in Display Technologies IV, 900508 (2014). CrossRef G.D. Love, A.F. Naumov, "Modal liquid crystal lenses", Liq. Cryst. Today 10, 1 (2000). CrossRef V. Urruchi, J.F. Algorri, J.M. Sánchez-Pena, M.A. Geday, X. Quintana, N. Bennis, "Lenticular Arrays Based on Liquid Crystals", Opto-Electron. Rev. 20, 38 (2012). CrossRef J.F. Algorri, G. Love, and V. Urruchi, "Modal liquid crystal array of optical elements", Opt. Express 21, 24809 (2013). CrossRef J.F. Algorri, V. Urruchi, N. Bennis, J. Sánchez-Pena, "Modal liquid crystal microaxicon array", Opt. Lett. 39, 3476 (2014). CrossRef J.F. Algorri, V. Urruchi, B. Garcia-Camara, J.M. Sánchez-Pena, "Generation of Optical Vortices by an Ideal Liquid Crystal Spiral Phase Plate", IEEE Elect. Dev. Lett. 35, 856 (2014). CrossRef D. Xu, Y. Chen, Y. Liu, S. Wu, "Refraction effect in an in-plane-switching blue phase liquid crystal cell", Opt. Express 21, 24721 (2013). CrossRef Z. Ge, S. Gauza, M. Jiao, H. Xianyu, S.T. Wu, "Electro-optics of polymer-stabilized blue phase liquid crystal displays", Appl. Phys. Lett. 94 101104 (2009). CrossRef J. Yan et al., "Extended Kerr effect of polymer-stabilized blue-phase liquid crystals", Appl. Phys. Lett. 96, 071105 (2010). CrossRef X. Wang, D. Wilson, R. Muller, P. Maker, D. Psaltis, "Liquid-crystal blazed-grating beam deflector, Appl. Opt. 39, 6545 (2000). CrossRef
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46

Bailey, Adam, Rosalind King, and Guillaume Backé. "Integration of structural, stress, and seismic data to define secondary permeability networks through deep-cemented sediments in the Northern Perth Basin." APPEA Journal 52, no. 1 (2012): 455. http://dx.doi.org/10.1071/aj11036.

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Understanding natural fracture networks has increasingly been recognised as an important factor for the prospectivity of a geothermal play, as they commonly exert a prime control over permeability at depth. The onshore Northern Perth Basin provides a good example of how fracture stimulation, and subsequent enhancement of the structural permeability, during hydrocarbon production can enhance flow rate from original tight gas reservoirs. Low primary porosity and permeability values have been initially recorded in the Northern Perth Basin due to silica-rich groundwater infiltration and consequent quartz cementation. Geothermal energy prospectivity in the region will therefore depend heavily on similar engineering techniques or on the presence of secondary permeability due to interconnected natural fractures. The existence and extent of these natural fractures are verified in this study through an integrated analysis of geophysical logs (including wellbore image logs), wells tests, and 3D seismic data. Wellbore image logs from 11 petroleum wells in the Northern Perth Basin are used to identify borehole failure (such as borehole breakout and drilling-induced tensile fractures) to give a present-day maximum horizontal stress orientation of N076°E (with an s.d. of 13°). Density logs and leak off tests from 13 petroleum wells are used to constrain the present-day stress magnitudes, giving a transitional strike-slip fault to reverse-fault stress regime in the Northern Perth Basin. 870 fractures are identified in image logs from 13 petroleum wells in the Northern Perth Basin, striking roughly north to south and northwest to northeast. Fractures aligned in the present-day stress field are optimally oriented for reactivation, and are hence likely to be open to fluid flow. Electrically resistive and conductive natural fractures are identified on the wellbore image logs. Resistive fractures are considered to be cemented with electrically resistive cement (such as quartz or calcite) and thus closed to fluid-flow. Conductive fractures are considered to be uncemented and open to fluid-flow, and are thus important to geothermal exploration. Fracture susceptibility diagrams constructed for the identified fractures illustrate that the conductive fractures are optimally oriented for reactivation in the present-day strike-slip fault to reverse-fault stress regime, and so are likely to be open to fluid flow. This is reinforced by the correlation of drilling fluid loss and conductive natural fractures in three wells in the Northern Perth Basin. To gain an understanding of the extent and interconnectedness of these fractures, it is necessary to look at more regional data, such as 3D seismic surveys. It is, however, well-documented that fault and fracture networks like those generally observed in image logs lie well below seismic amplitude resolution, making them difficult to observe directly on amplitude data. Seismic attributes can be calculated to provide some information on sub-seismic scale structural and stratigraphic features. Using a 3D seismic cube acquired over the Dongara North gas field, attribute maps of complex multi-trace dip-steered coherency and most positive curvature were used to document the presence of natural fractures and to best constrain the likely extent of the fracture network. The resulting fracture network model displays relatively good connectivity, which is likely to extend across much of the basin. These optimally oriented fractures are therefore likely to form a secondary permeability network throughout the cemented sediments of the Northern Perth Basin, offering potential deep fluid flow conduits, which may be exploited for the production of geothermal energy.
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47

Lewis Scott, William, and Naomi Ehrich Leonard. "Minimum-Time Trajectories for Steered Agent With Constraints on Speed, Lateral Acceleration, and Turning Rate." Journal of Dynamic Systems, Measurement, and Control 140, no. 7 (March 28, 2018). http://dx.doi.org/10.1115/1.4039283.

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We present time-optimal trajectories for a steered agent with constraints on speed, lateral acceleration, and turning rate for the problem of reaching a point on the plane in minimum time with free terminal heading angle. Both open-loop and state-feedback forms of optimal controls are derived through application of Pontryagin's minimum principle. We apply our results for the single agent to solve a multi-agent coverage problem in which each agent has constraints on speed, lateral acceleration, and turning rate.
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48

Ram, Gopi. "Multi‐beam steered harmonic pattern synthesis in timed antenna array with optimized and pre‐defined RF switching." International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, May 31, 2021. http://dx.doi.org/10.1002/jnm.2912.

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49

Vandecappelle, Servaas, Lucas Deckers, Neetha Das, Amir Hossein Ansari, Alexander Bertrand, and Tom Francart. "EEG-based detection of the locus of auditory attention with convolutional neural networks." eLife 10 (April 30, 2021). http://dx.doi.org/10.7554/elife.56481.

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In a multi-speaker scenario, the human auditory system is able to attend to one particular speaker of interest and ignore the others. It has been demonstrated that it is possible to use electroencephalography (EEG) signals to infer to which speaker someone is attending by relating the neural activity to the speech signals. However, classifying auditory attention within a short time interval remains the main challenge. We present a convolutional neural network-based approach to extract the locus of auditory attention (left/right) without knowledge of the speech envelopes. Our results show that it is possible to decode the locus of attention within 1–2 s, with a median accuracy of around 81%. These results are promising for neuro-steered noise suppression in hearing aids, in particular in scenarios where per-speaker envelopes are unavailable.
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50

Zhu, Qing Li, Cong Du, Yahao Dai, Matthias Daab, Marian Matejdes, Josef Breu, Wei Hong, Qiang Zheng, and Zi Liang Wu. "Light-steered locomotion of muscle-like hydrogel by self-coordinated shape change and friction modulation." Nature Communications 11, no. 1 (October 14, 2020). http://dx.doi.org/10.1038/s41467-020-18801-1.

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Abstract Many creatures have the ability to traverse challenging environments by using their active muscles with anisotropic structures as the motors in a highly coordinated fashion. However, most artificial robots require multiple independently activated actuators to achieve similar purposes. Here we report a hydrogel-based, biomimetic soft robot capable of multimodal locomotion fueled and steered by light irradiation. A muscle-like poly(N-isopropylacrylamide) nanocomposite hydrogel is prepared by electrical orientation of nanosheets and subsequent gelation. Patterned anisotropic hydrogels are fabricated by multi-step electrical orientation and photolithographic polymerization, affording programmed deformations. Under light irradiation, the gold-nanoparticle-incorporated hydrogels undergo concurrent fast isochoric deformation and rapid increase in friction against a hydrophobic substrate. Versatile motion gaits including crawling, walking, and turning with controllable directions are realized in the soft robots by dynamic synergy of localized shape-changing and friction manipulation under spatiotemporal light stimuli. The principle and strategy should merit designing of continuum soft robots with biomimetic mechanisms.
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