Journal articles: 'Trajectory enhancement'

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UEDA, Satoshi, Takahiro ITO, and Shinichiro SAKAI. "Resilience Enhancement of Lunar Landing Trajectory Control Using Reinforcement Learning." Transactions of the Society of Instrument and Control Engineers 58, no. 3 (2022): 194–201. http://dx.doi.org/10.9746/sicetr.58.194.

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Kong, Zhan, Yaqi Cui, Wei Xiong, Zhenyu Xiong, and Pingliang Xu. "Ship Target Recognition Based on Context-Enhanced Trajectory." ISPRS International Journal of Geo-Information 11, no. 12 (November 23, 2022): 584. http://dx.doi.org/10.3390/ijgi11120584.

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Ship target recognition based on trajectories has great potential in the field of target recognition. In the existing research, the context information is ignored, which limits the improvement of ship target recognition ability. In addition, the process of trajectory feature extraction is complex, and recognition accuracy needs to be further improved. In this paper, a ship target recognition method based on a context-enhanced trajectory is proposed. The maritime context knowledge base is constructed to enhance the trajectory information and to improve the separability of different types of target trajectories. A deep learning model is used to extract trajectory features and context features automatically. Offline training and online recognition are adopted to complete the target recognition task. Experimental analysis and verification are carried out using the automatic identification system (AIS) dataset. The recognition accuracy increases by 7.91% after context enhancement, which shows that the context enhancement is efficient. The proposed method also has a strong anti-noise ability. In the noisy environment set in this paper, the recognition accuracy of the proposed method is still maintained at 86.13%.

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Xu, Yunjun. "Enhancement in Optimal Multiple-Burn Trajectory Computation by Switching Function Analysis." Journal of Spacecraft and Rockets 44, no. 1 (January 2007): 264–72. http://dx.doi.org/10.2514/1.25082.

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Kim, Tae-Hun, Chang-Hun Lee, and Min-Jea Tahk. "Time-to-go Polynomial Guidance with Trajectory Modulation for Observability Enhancement." IEEE Transactions on Aerospace and Electronic Systems 49, no. 1 (January 2013): 55–73. http://dx.doi.org/10.1109/taes.2013.6404091.

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Xu, Tianchen, Enhua Wu, Mo Chen, and Ming Xie. "Real-time Character Motion Effect Enhancement Based on Fluid Simulation." International Journal of Virtual Reality 11, no. 1 (January 1, 2012): 59–68. http://dx.doi.org/10.20870/ijvr.2012.11.1.2838.

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In fast figure animation, motion blur is of crucial importance, and this is especially true when an artist wants to generate exaggerating effect through figure motion. For a quite long period of time, animators seek the answer by using certain kind of image blending, no matter by the means of hardware or software. In recent years, methods based on 3D geometry of the motion figure with global illumination become gradually in demand, as they could deliver relatively high quality of motion blur effect. However, the computation cost in those methods is always very high, thus real time rendering become quite difficult to achieve. In this paper, a real-time motion effect based on 3D geometric approach is proposed, in which a special effect along the motion trajectory based on fluid simulation is combined with the volumetric motion blur. Furthermore, the motion trajectory would be decomposed and multi-pass geometry rendering would be employed to achieve geometry instancing for reuse. In this manner, the redundant calculation of each frame could be avoided, and the limitation of trajectory generation would be broken. In the pipeline, we separate motion tracking and fluid solution, to support various fluid effects flexibly. The scheme we present makes use of GPU geometry shading in parallel, aiming at guaranteeing high efficiency of computation while delivering splendid rendering. As a result, real time rendering including the motion blur effect is achieved.

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Zvîncu, N.-D., C.-E. Moldoveanu, A.-D. Mandache-Dodoiu, F.-M. Dîrloman, and I. Vedinaș. "Research on small caliber weapons firing ranges security enhancement considering the projectile-obstacle impact." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012086. http://dx.doi.org/10.1088/1757-899x/1182/1/012086.

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Abstract Weapons systems are used to gain a tactical, strategic, material or mental advantage over an adversary or enemy target. The modern weapons systems are designed to be technologically complex but practical for operator usage. The firing phenomenon consists of a multitude of mechanical and thermodynamic processes with the result being the movement of the projectile towards a chosen target. The projectile movement from the weapon to the point of impact defines its trajectory. Firing ranges are locations where military personnel is operating certain weapons systems in order to achieve specific results and certain levels of readiness. Due to increasing urbanisation of the areas adjacent to firing ranges, monitoring the projectile trajectory becomes mandatory in order to be able to provide a secure climate for both military personnel and civilians. It is the purpose of the author to provide the numerical simulation tool (a MATLAB application) which is useful for tracking the projectile trajectory from the muzzle of the weapon to the impacted obstacle. By computing the useful information obtained with the internal and external ballistics, the theoretical trajectory of a projectile can be calculated. In order to get the most accurate values, preliminary knowledge is needed. So by using appropriate tools and software, a projectile’s trajectory can be calculated if the correct values are provided (mass, diameter, initial angle, initial speed). The tool created has different weapons-ammunition specifications and initial conditions parameters loaded that can be combined with the existing drag laws known in ballistics (Siacci law, 1930 law or 1943 law) to describe the projectile movement in atmosphere. As obstacles are defined, similar to the ones existing in a firing range, the tool can assess where the impact occurred and is able to display necessary values (impact points coordinates, velocities, impact angles, etc) while also creating 3D and 2D visualisations on the integrated graphic area. This way, the tool can be used to create impact assessments for specific weapons systems and decisions can be made to enhance the security of the firing range and the firing safety. Three different firing range configurations are considered for comparison when using certain small caliber weapons used by NATO countries.

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Putnam, Zachary R., and Robert D. Braun. "Extension and Enhancement of the Allen–Eggers Analytical Ballistic Entry Trajectory Solution." Journal of Guidance, Control, and Dynamics 38, no. 3 (March 2015): 414–30. http://dx.doi.org/10.2514/1.g000846.

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Ha, S., and J. Kwon. "Visual tracking enhancement by trajectory simulation based on hidden semi‐Markov model." Electronics Letters 56, no. 2 (January 2020): 85–87. http://dx.doi.org/10.1049/el.2019.2877.

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Qin, Hao. "Trajectory Tracking Method of Volleyball Player’s Arm Hitting Image Based on D-P Algorithm." Scientific Programming 2021 (December 3, 2021): 1–9. http://dx.doi.org/10.1155/2021/4848036.

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Aiming at the problems of poor image tracking effect, low precision, and long time in the process of image tracking of volleyball player’s arm hitting, a volleyball player's arm hitting image tracking method based on D-P algorithm is proposed. This paper analyzes the basic concept, basic principle, and basic equation of D-P algorithm and collects the arm stroke trajectory image of volleyball players under the three-dimensional visual model. Using wavelet multiscale decomposition method, the arm stroke trajectory of volleyball players is filtered, and the edge contour feature points of the arm stroke image of volleyball players are extracted. Using the gray histogram feature extraction method, the gray information of volleyball player's arm hitting trajectory image is enhanced. Combined with pixel adaptive enhancement technology, the key action feature points of volleyball player's arm hitting image trajectory are located. Based on D-P algorithm, the volleyball player's arm hitting image trajectory is adjusted and modified to realize the correct tracking of volleyball player's arm hitting image trajectory. The experimental results show that the trajectory tracking effect of volleyball player's arm hitting image is better, which can effectively improve the tracking accuracy and shorten the tracking time.

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Leontyev, D. A., and A. E. Miyuzova. "Personality Changes as a Result of Life Enhancement Work." Консультативная психология и психотерапия 24, no. 1 (2016): 44–63. http://dx.doi.org/10.17759/cpp.2016240104.

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The paper presents empirical analysis of possible effects of participating in the author’s life enhancement master-classes and seminars of discovering existential experience. Original qualitative methods were used in the study: description of changes with subsequent content analysis and factor analysis of the categories, and visual method “Trajectory”. Both methods revealed satisfactory reliability, valid- ity and richness of content. It can be claimed that the effects of life enhancement work include changing the attitude to uncertainty and subjective expansion of per- ceived possibilities.

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MacKey, Wade C. "Father Presence: An Enhancement of a Child's Well-Being." Journal of Men’s Studies 6, no. 2 (March 1998): 227–43. http://dx.doi.org/10.1177/106082659800600207.

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For the last quarter of a century, American academics and literati have assumed that the traditional father figure was supernumerary and rather optional. This perspective viewed a child's life-space trajectory as little perturbed if a father was present or not. The present paper argues against this assumption. Available evidence clearly indicates that fathers do enhance their children's well-being. The problems aligned with fatherlessness are analyzed, and modest proposals are proffered to re-establish fathering as central to a child's growth and development within American society.

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Hartman, Christopher M., and Jerry Y. Harrington. "Radiative Impacts on the Growth of Drops within Simulated Marine Stratocumulus. Part I: Maximum Solar Heating." Journal of the Atmospheric Sciences 62, no. 7 (July 1, 2005): 2323–38. http://dx.doi.org/10.1175/jas3477.1.

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Abstract The effects of solar heating and infrared cooling on the vapor depositional growth of cloud drops, and hence the potential for collection enhancement, is investigated. Large eddy simulation (LES) of marine stratocumulus is used to generate 600 parcel trajectories that follow the mean motions of the cloud. Thermodynamic, dynamic, and radiative cloud properties are stored for each trajectory. An offline trajectory ensemble model (TEM) coupled to a bin microphysical model that includes the influences of radiation on drop growth is driven by the 600-parcel dataset. In line with previous results, including infrared cooling causes a reduction in the time for collection onset. This collection enhancement increases with drop concentration. Larger concentrations (400 cm−3) show a reduction in collection onset time of as much as 45 min. Including infrared cooling as well as solar heating in the LES and microphysical bin models has a number of effects on the growth of cloud drops. First, shortwave (SW) heating partially offsets cloud-top longwave (LW) cooling, which naturally reduces the influence of LW cooling on drop growth. Second, SW heating dominates over LW cooling at larger drop radii (≳200 μm), which causes moderately sized drops to evaporate. Third, unlike LW cooling, SW heating occurs throughout the cloud deck, which suppresses drop growth. All three of these effects tend to narrow the drop size spectrum. For intermediate drop concentrations (100–200 cm−3), it is shown that SW heating primarily suppresses collection initiation whereas at larger drop concentrations (≳250 cm−3) LW cooling dominates causing enhancements in collection.

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Zhuravleva, Larisa. "Motor vehicle unmanned driving technology enhancement." E3S Web of Conferences 262 (2021): 01008. http://dx.doi.org/10.1051/e3sconf/202126201008.

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The relevance of the introduction of unmanned vehicles, the improvement of their control systems is increasing every year due to the ever-increasing volume of cargo transportation. The undoubted advantages of the developed direction are the reduction of the influence of the human factor, management errors, and, consequently, reduction of the number of accidents, as well as reduction of the transportation costs. The research was aimed to develop the algorithmic, programmatic control of an unmanned vehicle when transporting goods along a given route, in particular, when unmanned vehicles move in a convoy behind a pilot vehicle with a given distance along an arbitrary trajectory. The article discusses the control algorithm, technical means of the control system and the technical vision tracking system. The article presents the results of experimental studies of the movement of an unmanned vehicle based on a serial KamAZ 6520 vehicle.

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Sato, Ryuta, Shogo Hasegawa, Keiichi Shirase, Masanobu Hasegawa, Akira Saito, and Takayuki Iwasaki. "Motion Accuracy Enhancement of Five-Axis Machine Tools by Modified CL-Data." International Journal of Automation Technology 12, no. 5 (September 5, 2018): 699–706. http://dx.doi.org/10.20965/ijat.2018.p0699.

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The motion trajectories of machine tools directly influence the geometrical shape of machined workpieces. Hence, improvement in their motion accuracy is required. It is known that machined shape errors occurring in numerical control (NC) machine tools can be compensated for by modifying the CL-data, based on the amount of error calculated by the measurement results of the machined shape of the workpiece. However, by using this method the shape errors cannot be compensated accurately in five-axis machining, because the final machining shape may not reflect the motion trajectory of a tool owing to the motion errors of the translational and rotary axes. In this study, a modification method of the cutter location (CL)-data, based on the amount of motion errors of the tool center-point trajectory during the machining motion, is newly proposed. The simulation and experiment of a wing profile machining motion is performed, to confirm the effectiveness of the proposed method. From the results, we confirm that the motion accuracy can be significantly improved by applying the proposed method.

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Jisha, K., and K. Pradeepa. "Lifetime enhancement of wireless sensor using multiple mobile data collectors and optimised trajectory." International Journal of Mobile Network Design and Innovation 10, no. 2 (2021): 104. http://dx.doi.org/10.1504/ijmndi.2021.118989.

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Pradeepa, K., and K. Jisha. "Lifetime enhancement of wireless sensor using multiple mobile data collectors and optimised trajectory." International Journal of Mobile Network Design and Innovation 10, no. 2 (2021): 104. http://dx.doi.org/10.1504/ijmndi.2021.10042687.

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Lai, S. C., A. K. Baker, T. J. Schuck, P. van Velthoven, D. E. Oram, A. Zahn, M. Hermann, et al. "Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines." Atmospheric Chemistry and Physics 10, no. 4 (February 15, 2010): 1649–60. http://dx.doi.org/10.5194/acp-10-1649-2010.

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Abstract. A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution events were observed, where enhancements in aerosol and trace gas concentrations including CO, CO2, CH4, non-methane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass/biofuel burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C2Cl4 during the events also indicate a substantial contribution from urban anthropogenic emissions. An estimation of the contribution of fossil fuel versus biomass/biofuel to the CO enhancement was made, indicating a biomass/biofuel burning contribution of ~54 to ~92% of the observed CO enhancements. Biomass/biofuel burning was found to be the most important source category during the sampling period.

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Kiryanov, Alexey V. "Accuracy Enhancement for Precision Angle Measuring Structures." Key Engineering Materials 437 (May 2010): 198–202. http://dx.doi.org/10.4028/www.scientific.net/kem.437.198.

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Producing high-quality optical limbs, circular scales, rasters, multibit code disks (key metrological elements hereinafter called “angle measuring structures” (AMS) is an important engineering problem for any manufacturer, making angle measuring gauges. The analysis of the precision parameters of the AMS that were made by the method of circular scanning has revealed that the distorted circular trajectory of the recording laser beam moving across the surface of a semimanufactured article to be the main source of errors in the AMS produced. The main reason causing the distortion has been the rotor imbalance in the spindle unit of the laser generator of images. The article offers solutions for accuracy enhancement in manufacturing precision angle measuring structures. It also describes error estimation process in the raster, manufactured upon implementing the solutions offered.

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Imes, Christopher C., Yaguang Zheng, Dara D. Mendez, Bonny J. Rockette-Wagner, Meghan K. Mattos, Rachel W. Goode, Susan M. Sereika, and Lora E. Burke. "Group-Based Trajectory Analysis of Physical Activity Change in a US Weight Loss Intervention." Journal of Physical Activity and Health 15, no. 11 (November 1, 2018): 840–46. http://dx.doi.org/10.1123/jpah.2017-0484.

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Background: The obesity epidemic is a global concern. Standard behavioral treatment including increased physical activity, reduced energy intake, and behavioral change counseling is an effective lifestyle intervention for weight loss. Purpose: To identify distinct step count patterns among weight loss intervention participants, examine weight loss differences by trajectory group, and examine baseline factors associated with trajectory group membership. Methods: Both groups received group-based standard behavioral treatment while the experimental group received up to 30 additional, one-on-one self-efficacy enhancement sessions. Data were analyzed using group-based trajectory modeling, analysis of variance, chi-square tests, and multinomial logistic regression. Results: Participants (N = 120) were mostly female (81.8%) and white (73.6%) with a mean (SD) body mass index of 33.2 (3.8) kg/m2. Four step count trajectory groups were identified: active (>10,000 steps/day; 11.7%), somewhat active (7500–10,000 steps/day; 28.3%), low active (5000–7500 steps/day; 27.5%), and sedentary (<5000 steps/day; 32.5%). Percent weight loss at 12 months increased incrementally by trajectory group (5.1% [5.7%], 7.8% [6.9%], 8.0% [7.4%], and 13.63% [7.0%], respectively; P = .001). At baseline, lower body mass index and higher perceived health predicted membership in the better performing trajectory groups. Conclusions: Within a larger group of adults in a weight loss intervention, 4 distinct trajectory groups were identified and group membership was associated with differential weight loss.

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XIAO, QING, WEI LIAO, and HUA-SHU DOU. "ENHANCEMENT ON PROPULSION PERFORMANCE: MODIFYING ANGLE OF ATTACK PROFILE." Modern Physics Letters B 24, no. 13 (May 30, 2010): 1353–56. http://dx.doi.org/10.1142/s0217984910023608.

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In this paper, numerical investigation was conducted for an oscillating NACA0012 foil combining the pitching and plunging motions. The plunging follows a sinusoidal motion while the pitching trajectory is controlled by achieving the resultant effective angle of attack (AOA) to be a harmonic cosine form. Computations were conducted over a range of the Strouhal number (St), different maximum effective AOA and different phase difference between pitching and plunging (ψ). Results show that, at higher St, significant improvement on propulsion performance has been achieved when the effective AOA profile maintains a harmonic cosine form by controlling the pitching motion of the foil.

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Li, Xianchang, and Ting Wang. "Simulation of Film Cooling Enhancement With Mist Injection." Journal of Heat Transfer 128, no. 6 (December 9, 2005): 509–19. http://dx.doi.org/10.1115/1.2171695.

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Cooling of gas turbine hot-section components, such as combustor liners, combustor transition pieces, and turbine vanes (nozzles) and blades (buckets), is a critical task for improving the life and reliability of them. Conventional cooling techniques using air-film cooling, impingement jet cooling, and turbulators have significantly contributed to cooling enhancements in the past. However, the increased net benefits that can be continuously harnessed by using these conventional cooling techniques seem to be incremental and are about to approach their limit. Therefore, new cooling techniques are essential for surpassing these current limits. This paper investigates the potential of film-cooling enhancement by injecting mist into the coolant. The computational results show that a small amount of injection (2% of the coolant flow rate) can enhance the adiabatic cooling effectiveness about 30–50%. The cooling enhancement takes place more strongly in the downstream region, where the single-phase film cooling becomes less powerful. Three different holes are used in this study including a two-dimensional (2D) slot, a round hole, and a fan-shaped diffusion hole. A comprehensive study is performed on the effect of flue gas temperature, blowing angle, blowing ratio, mist injection rate, and droplet size on the cooling effectiveness with 2D cases. Analysis on droplet history (trajectory and size) is undertaken to interpret the mechanism of droplet dynamics.

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Macek, Karel, Jiri Rojicek, Georgios Kontes, and Dimitrios V. Rovas. "Black-Box Optimization for Buildings and Its Enhancement by Advanced Communication Infrastructure." ADCAIJ: Advances in Distributed Computing and Artificial Intelligence Journal 2, no. 2 (August 31, 2013): 53–64. http://dx.doi.org/10.14201/adcaij2013255364.

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The solution of repeated fixed-horizon trajectory optimization problems of processes that are either too difficult or too complex to be described by physics-based models can pose formidable challenges. Very often, soft-computing methods e.g. black-box modeling and evolutionary optimization are used. These approaches are ineffective or even computationally intractable for searching high-dimensional parameter spaces. In this paper, a structured iterative process is described for addressing such problems: the starting point is a simple parameterization of the trajectory starting with a reduced number of parameters; after selection of values for these parameters so that this simpler problem is covered satisfactorily, a refinement procedure increases the number of parameters and the optimization is repeated. This continuous parameter refinement and optimization process can yield effective solutions after only a few iterations. To illustrate the applicability of the proposed approach we investigate the problem of dynamic optimization of the operation of HVAC (heating, ventilation, and air conditioning) systems, and illustrative simulation results are presented. Finally, the development of advanced communication and interoperability components is described, addressing the problem of how the proposed algorithm could be deployed in realistic contexts.

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Qin, Meiyan, Yi Zeng, Xin Zeng, and Qing Liao. "Enhancement of High-Order Harmonic Generation due to the Large Gradient of the Electric Field Amplitude." Applied Sciences 9, no. 2 (January 14, 2019): 282. http://dx.doi.org/10.3390/app9020282.

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The influence of the waveform of circularly polarized laser field on high-order harmonic (HH) generation from atoms is investigated by solving the time-dependent Schrödinger equation (TDSE) and by classical trajectory analysis, without assuming an initial transverse velocity. Both the HH simulation and the classical trajectory calculation demonstrate that the positive temporal gradient of the electric field amplitude is a key factor that makes the electron return to the parent ion possible. Moreover, the larger the temporal gradient of the field amplitude is, the more the electron trajectories will revisit the parent ion. Correspondingly, the enhancement of HH is observed. This is confirmed by the pulse-duration dependence of the harmonic yield driven by a circularly polarized laser field.

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Flury, T., S. C. Müller, K. Hocke, and N. Kämpfer. "Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis." Atmospheric Chemistry and Physics Discussions 8, no. 4 (July 18, 2008): 13775–99. http://dx.doi.org/10.5194/acpd-8-13775-2008.

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Abstract. The Institute of Applied Physics operates an airborne microwave radiometer that measures the rotational transition line of water vapor at 183.3 GHz. Measurements were acquired on board a Learjet once a year in the period 1998 to 2006. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabic Sea measured on our flight mission in November 2005 conducted during EC-project SCOUT-O3. The flight led from Switzerland to Australia and back. We find an enhancement of up to 25% in the lower mesospheric H2O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere. During the outward flight the air came from the Carribean and crossed the Atlantic Ocean. On the return flight the air came from China and orginated from mid latitudes. Thus the large variability of H2O VMR during our flight is explained by a change of the winds in the lower mesosphere.

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Abd zaid, Duaa Nadheer, and Dhafer A. Hamzah. "Heat Transfer Enhancement by Turbulence Generator inside Heat Receiver." Al-Qadisiyah Journal for Engineering Sciences 13, no. 4 (January 2, 2021): 268–73. http://dx.doi.org/10.30772/qjes.v13i4.680.

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Tubular heat exchanger (THEX), that has been in numerous engineering applications, represents an apparatus that makes heat to be exchanged between two fluids having different changing in temperatures and kept separated by means of a solid wall. In order to enhance the efficiency of the THEX, the rate of heat transfer at the tube side should be improved. Inserting a twisted tape inside the heat exchanger’s tube is one of the passive techniques that has been widely used to improve the heat transfer especially in air conditioning and cooling, processes of power recovery, processes for food and dairy, and plants for chemical processing. The heat exchanger enhancement is achieved by means of using a twisted tape inserted with twisting ratios (TR) equal to 3.2, 4.4, and 5.5, independently. The influences of 2-D parameters such as Nusselt number and frictional coefficient on the THEX’s effectiveness were investigated. The aim of the study is inserting a twisted tape inside the testing pipe to produced turbulent flow and, therefore, creating large turbulence rate inside the pipe that plays an significant role in improving the transferred heat and increasing the drop in the pressure. In this work, the inserted tape has a width and length equal to 21.5 mm and 1000 mm, respectively. The inner and outer diameters of the used pipes were 23 mm and 22 mm, respectively. The tested sectional length of the THEX was equal to 2000 mm. Reynolds number was changed from 500 to 7000. Results obtained from using twisted inserting tapes with varying TR were compared with result from plain tubes. These results were displayed in the contours show the distribution of the temperature and the trajectory of the flow trajectory by axial velocity for testing the low values of Reynolds number applicability in heat exchanger applications

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Gao, Wenxiang, Guizhi Yang, Yuzhang Wang, Jiaxin Ke, Xungao Zhong, and Lihua Chen. "Robust visual odometry based on image enhancement." Journal of Physics: Conference Series 2402, no. 1 (December 1, 2022): 012010. http://dx.doi.org/10.1088/1742-6596/2402/1/012010.

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Abstract With the rise of augmented reality and autonomous driving, visual SLAM (simultaneous localization and mapping) has become the focus of research again. Visual odometry is an important part of visual SLAM. Too dark or too strong light will reduce the image quality, resulting in a large deviation in the visual odometry trajectory. Therefore, this paper proposes a visual odometry with image enhancement. Identify the lighting state of the image by estimating the brightness value of the input image. Gamma correction based on truncated cumulative distribution function modulation is used to enhance images that are too dark. For too strong images, negative image strategy is used. An improved algorithm can boost the detailed texture of the image in a poor lighting environment accurately, thereby improving the accuracy of feature point matching and the precision of the pose estimation. Tests on the public EuRoC dataset demonstrate that the presented algorithm has better localization precision and robustness.

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Flury, T., S. C. Müller, K. Hocke, and N. Kämpfer. "Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis." Atmospheric Chemistry and Physics 8, no. 23 (December 10, 2008): 7273–80. http://dx.doi.org/10.5194/acp-8-7273-2008.

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Abstract. The Institute of Applied Physics operates an airborne microwave radiometer AMSOS that measures the rotational transition line of water vapor at 183.3 GHz. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabian Sea. The measurements took place on our flight from Switzerland to Australia and back in November 2005 conducted during EC- project SCOUT-O3. We find an enhancement of up to 25% in the lower mesospheric H2O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere and wind fields from ECMWF. During the outward flight the air came from the Atlantic Ocean around 25 N and 40 W. On the return flight the air came from northern India and Nepal around 25 N and 90 E. Mesospheric H2O measurements from Aura/MLS confirm the transport processes of H2O derived by trajectory analysis of the AMSOS data. Thus the large variability of H2O VMR during our flight is explained by a change of the winds in the lower mesosphere. This study shows that trajectory analysis can be applied in the mesosphere and is a powerful tool to understand the large variability in mesospheric H2O.

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Zhou, Siqi, Mohamed K. Helwa, and Angela P. Schoellig. "Deep neural networks as add-on modules for enhancing robot performance in impromptu trajectory tracking." International Journal of Robotics Research 39, no. 12 (September 11, 2020): 1397–418. http://dx.doi.org/10.1177/0278364920953902.

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High-accuracy trajectory tracking is critical to many robotic applications, including search and rescue, advanced manufacturing, and industrial inspection, to name a few. Yet the unmodeled dynamics and parametric uncertainties of operating in such complex environments make it difficult to design controllers that are capable of accurately tracking arbitrary, feasible trajectories from the first attempt (i.e., impromptu trajectory tracking). This article proposes a platform-independent, learning-based “add-on” module to enhance the tracking performance of black-box control systems in impromptu tracking tasks. Our approach is to pre-cascade a deep neural network (DNN) to a stabilized baseline control system, in order to establish an identity mapping from the desired output to the actual output. Previous research involving quadrotors showed that, for 30 arbitrary hand-drawn trajectories, the DNN-enhancement control architecture reduces tracking errors by 43% on average, as compared with the baseline controller. In this article, we provide a platform-independent formulation and practical design guidelines for the DNN-enhancement approach. In particular, we: (1) characterize the underlying function of the DNN module; (2) identify necessary conditions for the approach to be effective; (3) provide theoretical insights into the stability of the overall DNN-enhancement control architecture; (4) derive a condition that supports data-efficient training of the DNN module; and (5) compare the novel theory-driven DNN design with the prior trial-and-error design using detailed quadrotor experiments. We show that, as compared with the prior trial-and-error design, the novel theory-driven design allows us to reduce the input dimension of the DNN by two thirds while achieving similar tracking performance.

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Slawson, P. R., G. J. Hitchman, and L. E. Hawker. "The Characteristic Behavior of Finite Length Line Sources of Heat in a Crossflow." Journal of Heat Transfer 112, no. 2 (May 1, 1990): 349–55. http://dx.doi.org/10.1115/1.2910384.

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A modified simple integral model for plume behavior from finite length line sources of heat and momentum is presented that identifies observed trends in plume trajectory data. Experiments on several finite length line sources of heat and momentum in the form of elevated (rows of stacks) and surface (slot) releases were conducted in a water tunnel. Plume behavior was documented through detailed temperature measurements of the plume cross section and by photographing the dyed plume. Results indicate the nature of any plume trajectory and growth enhancement and confirm the empirical relation for the liftoff distance for a buoyant surface plume given by Meroney (1979). In addition to the liftoff distance, the shape of the plume contact zone was measured and related to various regions of plume trajectory and cross-sectional shape. Plume trajectories from elevated line releases are adequately predicted by standard single source formulations; however, plume cross-sectional area is significantly overpredicted

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Swain, Prafulla Kumar, Ashok K. Barik, Siva Prasad Dora, and Rajeswara Resapu. "The propulsion of tandem flapping foil following fishtailed flapping trajectory." Physics of Fluids 34, no. 12 (December 2022): 123609. http://dx.doi.org/10.1063/5.0128223.

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It has always been a challenge to implement the natural flyer and swimmer kinematics into human-made aero/hydro vehicles for the enhancement of their performance. The propulsive performance of underwater vehicles can be enhanced by following the fishtailed kinematics. In the present study, a two-dimensional simulation has been performed on a tandem flapping foil by altering the simple flapping trajectory motion to a fishtailed trajectory by varying the Strouhal number ( St) in the range of 0.1–0.5. The effect of the inter-foil spacing and phasing between the foils on wake interaction is also investigated. The results show that fishtailed trajectory motion and inter-foil spacing of 2 cm–3 cm (where cm is the mean chord length) between the foils would enhance the propulsive efficiency of the downstream foil by up to 41%. The unfavorable spacing between the foils results in adverse wake interaction, which reduces the propulsive efficiency compared to solo flapping foil.

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Miao, Jiansong, Haoqiang Chen, Hairui Li, and Shanling Bai. "Secrecy Energy Efficiency Enhancement in UAV-Assisted MEC System." Sensors 23, no. 2 (January 8, 2023): 723. http://dx.doi.org/10.3390/s23020723.

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A secrecy energy efficiency optimization scheme for a multifunctional unmanned aerial vehicle (UAV) assisted mobile edge computing system is proposed to solve the computing power and security issues in the Internet-of-Things scenario. The UAV can switch roles between a computing UAV and jamming UAV based on the channel conditions. To ensure the security of the content and the system energy efficiency in the process of offloading computing tasks, the UAV trajectory, uplink transmit power, user scheduling, and offload task are jointly optimized, and an updated-rate assisted block coordinate descent (BCD) algorithm is used. Simulation results show that this scheme efficiently improves the secrecy performance and energy efficiency of the system. Compared with the benchmark scheme, the secrecy energy efficiency of the scheme is improved by 38.5%.

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Krstic, Predrag. "The better human, the better than human: Limits of enhancement." Filozofija i drustvo 23, no. 2 (2012): 124–44. http://dx.doi.org/10.2298/fid1202124k.

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Using the representations of science, fiction and science fiction, this article attempts to sketch out a certain line of development in the history of representation of the enhanced human. First it was thought that chemicals could temporarily or permanently improve his natural abilities, then artificial substitutes, inserts and accessories dominated the vision of his improvement. The most recent possibility announced is the fundamental morphological transformation of his biological composition into a completely unrecognizable, amorphous ?entity? capable of taking any form. This trajectory of ?improvement? of human capacities could be regarded as a gradual advancement in the realization of the pledge of traditional humanism: that man is special precisely for being able to become anything he chooses.

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Tarafder, Anik, Abhilash Reddy Malipeddi, and Kausik Sarkar. "Pair interactions between viscous drops in a viscoelastic matrix in free shear: Transition from passing to tumbling trajectories." Journal of Rheology 66, no. 3 (May 2022): 571–84. http://dx.doi.org/10.1122/8.0000374.

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Shear-induced pair interactions between viscous drops suspended in a viscoelastic matrix are numerically investigated examining the effects of elasticity and drop deformability on their post-collision trajectory. Two different trajectory types are identified depending on the Weissenberg number Wi and capillary number Ca. Drops suspended in a Newtonian matrix ( Wi = 0.0) show a passing trajectory where drops slide past each other and separate in the stream-wise direction. However, when increasing the Weissenberg number above a critical value, a tumbling/doublet trajectory is observed where two drops rotate around the midpoint of the line joining their centers, as was also seen previously for rigid particles. The tumbling trajectory is explained by investigating the flow around a single drop in shear. Elasticity generates a larger region of spiraling streamlines around a drop, which, during a pair interaction, traps the second drop giving rise to the tumbling pair. Decreasing deformability (lower Ca) and increasing viscoelasticity (higher Wi) favor a tumbling trajectory. With simulations sweeping the parameter space, we obtain a phase plot of the two different trajectories as functions of Ca and Wi. Treating the tension along the curved streamlines due to the non-zero first normal stress difference in the viscoelastic medium as an enhancement to the interfacial tension, we have developed an approximate force balance model for the zone of spiraling streamlines. It qualitatively captures the observed scaling of the critical Ca and Wi values at the phase boundary. The effects of unequal size, initial configuration, and non-unity viscosity ratio are briefly investigated.

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Majewska, Natalia Krystyna, Marcin Stański, Joanna Ryczkowska, Jacek Wątorek, Alicja Stańska, Mateusz Wykrętowicz, Małgorzata Pyda, and Katarzyna Katulska. "The Usefulness of MRI Dynamic Flow Sequences in Differentiating High- and Low-Flow Vascular Malformations." Journal of Clinical Medicine 12, no. 1 (December 23, 2022): 101. http://dx.doi.org/10.3390/jcm12010101.

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Peripheral arteriovenous malformations (PVMs) can be classified into high-flow malformations (HFVMs) and low-flow malformations (LFVMs). Adequate distinguishment is crucial for therapeutic decision and can be done using dynamic contrast-enhanced MRI (DCE-MRI). The main aim of this retrospective study was to determine the diagnostic value of quantitative DCE-MRI ratios for differentiation between HFVM and LFVM, their optimal cut-off points, and predictive values. DCE-MRI time-resolved angiography with stochastic trajectory (TWIST) examinations of 90 patients with PVMs were included [28 HFVM (31%), 62 LFVM (69%)]. The measurements of artery-lesion time, maximum lesion enhancement, slope of the enhancement curve, and maximum percentage increase of signal intensity (SI) were obtained. The optimal cut-offs for HFVMs calculated using the Youden index were: for slope of enhancement curve < 8.7 s (sensitivity of 86%, specificity of 89%), artery-lesion time ≤ 5.6 s (sensitivity of 89%, specificity of 77%), time to maximum enhancement ≤ 30 s (sensitivity of 94%, specificity of 100%), and maximum percentage enhancement of the lesion > 662% (sensitivity of 68%, specificity of 69%). To summarize, DCE-MRI is very valuable for differentiation between HFVM and LFVM, especially if quantitative measurements are done.

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Vassilakis, Costas, Konstantinos Kotis, Dimitris Spiliotopoulos, Dionisis Margaris, Vlasios Kasapakis, Christos-Nikolaos Anagnostopoulos, Georgios Santipantakis, et al. "A Semantic Mixed Reality Framework for Shared Cultural Experiences Ecosystems." Big Data and Cognitive Computing 4, no. 2 (April 20, 2020): 6. http://dx.doi.org/10.3390/bdcc4020006.

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This paper presents SemMR, a semantic framework for modelling interactions between human and non-human entities and managing reusable and optimized cultural experiences, towards a shared cultural experience ecosystem that might seamlessly accommodate mixed reality experiences. The SemMR framework synthesizes and integrates interaction data into semantically rich reusable structures and facilitates the interaction between different types of entities in a symbiotic way, within a large, virtual, and fully experiential open world, promoting experience sharing at the user level, as well as data/application interoperability and low-effort implementation at the software engineering level. The proposed semantic framework introduces methods for low-effort implementation and the deployment of open and reusable cultural content, applications, and tools, around the concept of cultural experience as a semantic trajectory or simply, experience as a trajectory (eX-trajectory). The methods facilitate the collection and analysis of data regarding the behaviour of users and their interaction with other users and the environment, towards optimizing eX-trajectories via reconfiguration. The SemMR framework supports the synthesis, enhancement, and recommendation of highly complex reconfigurable eX-trajectories, while using semantically integrated disparate and heterogeneous related data. Overall, this work aims to semantically manage interactions and experiences through the eX-trajectory concept, towards delivering enriched cultural experiences.

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Krishnamurthy, Vikram, and Sijia Gao. "Syntactic Enhancement to VSIMM for Roadmap Based Anomalous Trajectory Detection: A Natural Language Processing Approach." IEEE Transactions on Signal Processing 66, no. 20 (October 15, 2018): 5212–27. http://dx.doi.org/10.1109/tsp.2018.2866386.

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Humaidi, Amjad J., and Ahmed Ibraheem Abdulkareem. "Design of Augmented Nonlinear PD Controller of Delta/Par4-Like Robot." Journal of Control Science and Engineering 2019 (July 1, 2019): 1–11. http://dx.doi.org/10.1155/2019/7689673.

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This work presents the design of two control schemes for a Delta/Par4-like parallel robot: augmented PD (APD) controller and augmented nonlinear PD (ANPD) controller. The stability of parallel robot based on nonlinear PD controller has been analyzed and proved based on Lyapunov method. A comparison study between APD and ANPD controllers has been made in terms of performance and accuracy improvement of trajectory tracking. Also, another comparison study has been presented between augmented nonlinear PD (ANPD) controller and nonaugmented nonlinear PD (NANPD) controller in order to show the enhancement of introducing the augmented structure on dynamic performance and trajectory tracking accuracy. The effectiveness of augmented PD controllers (APD and ANPD) and nonaugmented nonlinear PD (NANPD) controller for the considered parallel robot are verified via simulation within the MATLAB environment.

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Peng, Yongwei, and Weiyi Gao. "Research on Reconstruction of Basketball Training Action Trajectory Based on Improved K-Means Clustering Algorithm." Wireless Communications and Mobile Computing 2022 (April 14, 2022): 1–9. http://dx.doi.org/10.1155/2022/9531266.

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The automatic capture and analysis of basketball game movements can guide basketball training and provide an effective method for improving the efficiency of basketball training. This paper introduces the research status of clustering methods in the field of trajectory data mining and reconstruction in detail. By analyzing the trajectory data under the constraints of the road network, the spatiotemporal characteristics of the existing trajectory clustering methods, and the deficiencies of the existing trajectory clustering methods, a new trajectory clustering method based on trajectory segmentation and spatiotemporal similarity measurement is implemented. A motion capture and reconstruction method for basketball training based on visual image K-means clustering algorithm is proposed. Multiresolution frame scanning technology is used to collect machine images of basketball training movements, and edge contour processing is performed on the collected high-resolution basketball training movement images. Feature detection uses the three-dimensional model reconstruction method to segment the basketball training action area and combines the irregular triangle network model to realize the machine vision block template matching processing of basketball training actions and capture the basketball training action in the Gaussian fuzzy affine space. In time and feature extraction, wavelet lifting technology is used to identify the ambiguity of basketball training movements, image enhancement technology is used to improve the resolution and adaptability of basketball training movement capture, and machine vision image processing methods are used to achieve basketball training movement capture optimization. The simulation results show that the method has better adaptability and higher feature recognition ability for basketball training motion capture and improves the feature extraction and adaptive capture reconstruction ability of basketball training motion.

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Putt, Shelby S., and Sobanawartiny Wijeakumar. "Tracing the evolutionary trajectory of verbal working memory with neuro-archaeology." Interaction Studies 19, no. 1-2 (September 17, 2018): 272–88. http://dx.doi.org/10.1075/is.17042.put.

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Abstract We used optical neuroimaging to explore the extent of functional overlap between working memory (WM) networks involved in language and Early Stone Age toolmaking behaviors. Oldowan tool production activates two verbal WM areas, but the functions of these areas are indistinguishable from general auditory WM, suggesting that the first hominin toolmakers relied on early precursors of verbal WM to make simple flake tools. Early Acheulian toolmaking elicits activity in a region bordering on Broca’s area that is involved in both visual and verbal WM tasks. The sensorimotor and mirror neurons in this area, along with enhancement of general WM capabilities around 1.8 million years ago, may have provided the scaffolding upon which a WM network dedicated to processing exclusively linguistic information could evolve. In the road map going forward, neuro-archaeologists should investigate the trajectory of WM over the course of human evolution to better understand its contribution to language origins.

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Mazzaro, Nazarena, Michael J. Grey, Thomas Sinkjær, Jacob Buus Andersen, Davide Pareyson, and Marco Schieppati. "Lack of On-Going Adaptations in the Soleus Muscle Activity During Walking in Patients Affected by Large-Fiber Neuropathy." Journal of Neurophysiology 93, no. 6 (June 2005): 3075–85. http://dx.doi.org/10.1152/jn.01071.2004.

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The aim of this study was to investigate the contribution of feedback from large-diameter sensory fibers to the adaptation of soleus muscle activity after small ankle trajectory modifications during human walking. Small-amplitude and slow-velocity ankle dorsiflexion enhancements and reductions were applied during the stance phase of the gait cycle to mimic the normal variability of the ankle trajectory during walking. Patients with demyelination of large sensory fibers (Charcot-Marie-Tooth type 1A and antibodies to myelin-associated glycoprotein neuropathy) and age-matched controls participated in this study. The patients had absent light-touch sense in the toes and feet and absent quadriceps and Achilles tendon reflexes, indicating functional loss of large sensory fibers. Moreover, their soleus stretch reflex response consisted of a single electromyographic (EMG) burst with delayed onset and longer duration ( P < 0.01) than the short- and medium-latency reflex responses observed in healthy subjects. In healthy subjects, the soleus EMG gradually increased or decreased when the ankle dorsiflexion was, respectively, enhanced or reduced. In the patients, the soleus EMG increased during the dorsiflexion enhancements; however, the velocity sensitivity of this response was decreased compared with the healthy volunteers. When the dorsiflexion was reduced, the soleus EMG was unchanged. These results indicate that the enhancement of the soleus EMG is mainly sensitive to feedback from primary and secondary muscle spindle afferents and that the reduction may be mediated by feedback from the group Ib pathways. This study provides evidence for the role of sensory feedback in the continuous adaptation of the soleus activity during the stance phase of human walking.

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von Clarmann, T., N. Glatthor, G. P. Stiller, U. Grabowski, M. Höpfner, S. Kellmann, A. Linden, et al. "MIPAS measurements of upper tropospheric C2H6 and O3 during the Southern hemispheric biomass burning season in 2003." Atmospheric Chemistry and Physics Discussions 7, no. 4 (August 15, 2007): 12067–95. http://dx.doi.org/10.5194/acpd-7-12067-2007.

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Abstract. Under cloud free conditions, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) provides measurements of spectrally resolved limb radiances down to the upper troposphere. These are used to infer global distributions of mixing ratios of atmospheric constituents in the upper troposphere and the stratosphere. From 21 October to 14 November 2003, MIPAS observed enhanced amounts of upper tropospheric C2H6 (up to about 400 pptv, depending on spectroscopic data chosen) and ozone (up to about 80 ppbv). By means of trajectory calculations, the enhancements observed in the Southern hemisphere are, at least partly, attributed to a biomass burning plume, which covers wide parts of the Southern hemisphere, from South America, the Atlantic ocean, Africa, the Indian Ocean to Australia. The chemical composition of the part of the plume-like pollution belt associated with South American rainforest burning appears different from the part associated with Southern African savanna burning. In particular, African savanna fires lead to a larger ozone enhancement than South American rainforest fires.

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Terrazas Gonzalez, Jesus D., and Witold Kinsner. "A Modular Dynamical Cryptosystem Based on Continuous-Interval Cellular Automata." International Journal of Cognitive Informatics and Natural Intelligence 5, no. 4 (October 2011): 83–109. http://dx.doi.org/10.4018/jcini.2011100106.

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This paper presents a new cryptosystem based on chaotic continuous-interval cellular automata (CCA) to increase data protection as demonstrated by their flexibility to encrypt and decrypt information from distinct sources. Enhancements to cryptosystems are also presented including (i) a model based on a new chaotic CCA attractor, (ii) the dynamical integration of modules containing dynamical systems to generate complex sequences, and (iii) an enhancement for symmetric cryptosystems by allowing them to generate an unlimited number of keys. This paper also presents a process of mixing chaotic sequences obtained from cellular automata, instead of using differential equations, as a basis to achieve higher security and higher speed for the encryption and decryption processes, as compared to other recent approaches. The complexity of the mixed sequences is measured using the variance fractal dimension trajectory to compare them to the unmixed chaotic sequences to verify that the former are more complex. This type of polyscale measure and evaluation has never been done in the past outside this research group.

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Roest, Geoffrey, and Gunnar Schade. "Quantifying alkane emissions in the Eagle Ford Shale using boundary layer enhancement." Atmospheric Chemistry and Physics 17, no. 18 (September 20, 2017): 11163–76. http://dx.doi.org/10.5194/acp-17-11163-2017.

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Abstract. The Eagle Ford Shale in southern Texas is home to a booming unconventional oil and gas industry, the climate and air quality impacts of which remain poorly quantified due to uncertain emission estimates. We used the atmospheric enhancement of alkanes from Texas Commission on Environmental Quality volatile organic compound monitors across the shale, in combination with back trajectory and dispersion modeling, to quantify C2–C4 alkane emissions for a region in southern Texas, including the core of the Eagle Ford, for a set of 68 days from July 2013 to December 2015. Emissions were partitioned into raw natural gas and liquid storage tank sources using gas and headspace composition data, respectively, and observed enhancement ratios. We also estimate methane emissions based on typical ethane-to-methane ratios in gaseous emissions. The median emission rate from raw natural gas sources in the shale, calculated as a percentage of the total produced natural gas in the upwind region, was 0.7 % with an interquartile range (IQR) of 0.5–1.3 %, below the US Environmental Protection Agency's (EPA) current estimates. However, storage tanks contributed 17 % of methane emissions, 55 % of ethane, 82 % percent of propane, 90 % of n-butane, and 83 % of isobutane emissions. The inclusion of liquid storage tank emissions results in a median emission rate of 1.0 % (IQR of 0.7–1.6 %) relative to produced natural gas, overlapping the current EPA estimate of roughly 1.6 %. We conclude that emissions from liquid storage tanks are likely a major source for the observed non-methane hydrocarbon enhancements in the Northern Hemisphere.

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Juhairi Aziz Safar, Muhammad, Keigo Watanabe, Shoichi Maeyama, and Isaku Nagai. "Tip-over stability enhancement for omnidirectional mobile robot." International Journal of Intelligent Unmanned Systems 2, no. 2 (May 6, 2014): 91–106. http://dx.doi.org/10.1108/ijius-12-2013-0024.

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Purpose – The purpose of this paper is to analyze the stability behavior of the omnidirectional mobile robot with active dual-wheel caster (ADWC) assemblies and provide a stable trajectory without any tip-over incident. The omnidirectional mobile robot to be developed is for transporting cuboid-shaped objects. Design/methodology/approach – The omnidirectional transport mobile robot is designed using an ADWC assemblies structure, the tip-over occurrence is estimated based on the support forces of an active footprint, the tip-over direction is predicted, the tip-over stability is enhanced to prevent the tip-over occurrence and a fast traveling motion is provided. Findings – The omnidirectional mobile robot tends to tip-over more on the sides with small ranges of tip-over angle. The proposed method for estimating the tip-over occurrence and enhancing the stability using the gyroscopic torque device was feasible as the tip-over prevention system of the omnidirectional mobile robot with ADWC assemblies. Originality/value – The research addresses the study of the tip-over stability for the omnidirectional mobile robot that possesses an active footprint. It also addresses the prediction of the tip-over occurrence using the derived dynamical model together with force-angle stability measure and the tip-over stability enhancement method using a single-gimbal control moment gyro device.

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López, Esteban, Juergen Hahn, Lina M. Gómez, and Hernán Alvarez. "Input Trajectory Design for the Enhancement of State Estimation through a Set-Theoretic Approach to Observability." Industrial & Engineering Chemistry Research 59, no. 30 (June 29, 2020): 13631–41. http://dx.doi.org/10.1021/acs.iecr.0c01386.

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Mishra, Amardeep. "Autonomous obstacle avoidance maneuvering of thrust-vectored airship with neural network control." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 3 (October 9, 2019): 689–708. http://dx.doi.org/10.1177/0954410019879821.

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There has been a renewed interest in recent times in airship technology owing to its potential usage for applications ranging from defense, scientific exploration, advertising to even remote monitoring. For airships to expand operational profile, further enhancement of configurational features and control development for full autonomy are key technologies gaining attention. In this paper, beginning with the mathematical modeling of a thrust-vectored airship, the integrated motion planning and controller development for vehicle autonomy, taking into account various uncertainties, are dealt with. A rapidly exploring random tree-based obstacle avoidance path planning exercise is carried out to chart out a trajectory in the presence of obstacles. Then, a neural network-based sliding mode controller is subsequently designed that learns the unknown equivalent control in sliding mode control framework to track the reference trajectory. Simulation results presented at the end demonstrate the effectiveness of the approach.

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Hawas, Majli Nema. "Enhancement of stability margin based on dynamic brake strategy." Indonesian Journal of Electrical Engineering and Computer Science 15, no. 2 (August 1, 2019): 571. http://dx.doi.org/10.11591/ijeecs.v15.i2.pp571-580.

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The Rate of Change Kinetic Energy (RACKE) method achieves considerable reduction in computing time by virtue of the way that it does not need the solution of system equation beyond fault clearing time. In RACKE method the machine which tends to lose synchronism can be defined as that which has the largest negation RACKE value. The injection of the brake ought to be achieved when RACKE of the machine liable to be unstable reaches its maximum negative value. Elimination happens when RACKE of the machine is zero and disturbance angular velocity passes through zero changing sign from positive to negative. To defining the instant of injection and elimination of brake, RACKE method can be used to investigate the transient stability margin of a power system through evaluation of RACKE value at the instant of fault clearance. The simulation demonstrates that the applying of a braking resistor at the terminal of each of the machines, pulling of synchronism, simultaneously brings the system into stable trajectory. It is clear from the results obtained that dynamic braking depending on the RACKE criterion for insertion and removal of the brake gives excellent results in an enhancement of transient stability margin.

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Bae, Hansin, Ikumi Hamaguchi, Kensuke Sasai, Haruka Suzuki, and Hirotaka Toyoda. "Enhancement of the ion flux to the substrate through high-voltage biasing in an electron cyclotron resonance plasma and its application to high-speed deposition of conductive carbon film." Japanese Journal of Applied Physics 60, no. 12 (December 1, 2021): 126002. http://dx.doi.org/10.35848/1347-4065/ac32b6.

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Abstract A method for enhancing ion flux to the substrate via high-voltage pulse biasing is investigated in an electron cyclotron resonance plasma. When high-voltage pulse biases above 500 V are applied to the stage, an increase in the stage current is observed, especially in the case of diverging magnetic field configurations in front of the bias stage. The growth and decay time constants of the plasma density and emission intensity are evaluated using a time-resolved Langmuir probe and emission spectroscopy while the pulse is on, and the enhancement of the ionization rate during the bias application is estimated using the zero-dimensional global model. The estimated density enhancement from the model is in good agreement with the measured one. From the numerical simulation of secondary electron trajectory, it is concluded that the electron confinement from the magnetic field is the key factor in plasma density enhancement during stage biasing. Using the high-density plasma produced by the bias voltage, conductive carbon is deposited at a high deposition rate of ∼4 nm s−1.

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Wang, S. Kong, Tzu-Chen Hung, Bau-Shi Pei, An-Fong Chen, and Ja-Lin Du. "A Numerical Study of the Enhancement of Chip Cooling via a Flow-Disturbing Obstruction Block." Journal of Electronic Packaging 127, no. 4 (May 3, 2005): 523–29. http://dx.doi.org/10.1115/1.2070089.

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Two-dimensional convection heat transfer on a chip with a flow-disturbing obstruction block above it, as induced by natural coupling between flow and structure, was investigated numerically. The effects of various induced trajectories of the obstruction block on chip cooling were investigated. A numerical algorithm PISO, a conjugate heat transfer scheme for fluid-solid thermal interactions with moving grids was used to solve a coupled system of governing equations. The study shows that the induced trajectories of the obstruction block, as a result of natural coupling between the block and the flow, have a noticeable impact on chip cooling. The present study successfully simulated the motion of an obstruction block on a heated chip and the associated “lock-in” phenomenon due to natural coupling. When lock-in occurs, the trajectory of the block movement follows the shape of an oval. If this occurs, the cross-stream movement is much larger than the stream-wise movement. Passively induced disturbance of the flow field for the case with a large oval trajectory yields an enhancement of heat dissipation from the chip. In general, the vibration of the block as induced by an unbalanced pressure field around the chip would disturb the thermal boundary above the chip. Hence, the induced vibration enhances heat dissipation from the chip. It is concluded in this study that a vibrating obstruction block with a lock-in mode of oscillation is a vital condition for achieving an enhancement of heat dissipation as can be observed by an increase of Nusselt number on the chip top surface.

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Miroshnikov, S. A., S. V. Notova, and Yu N. Nikulina. "Personnel Cooperation Between University and Industrial Partners in the Context of Youth Career Development." Vysshee Obrazovanie v Rossii = Higher Education in Russia 31, no. 8-9 (September 17, 2022): 99–115. http://dx.doi.org/10.31992/0869-3617-2022-31-8-9-99-115.

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The article has a research, practice-oriented nature and analyzes the problems of professional development and building a career trajectory of graduates through the prism of the personnel partnership of university and the business community. The purpose of the article is to explore the personnel cooperation between university and industrial partners in the context of professional development tracks and, in the light of this, develop a cyclogram of youth career development.The article presents the results of the study of factors influencing the formation of a career trajectory from the position of students of Orenburg State University (2022). The practice of implementing the formats of personnel partnership of the university and employers of Orenburg State University, including various activities within the framework of building the trajectory of professional and career development of a future specialist, is analyzed.The authors propose recommendations for the development of a cyclogram of students’ career development, improvement of the efficiency of interaction between the university and personnel partners by creating a student association of professional development focused on enhancement of career guidance activities at university, identifying creative, scientific, and entrepreneurial potential of students, developing skills necessary to increase competitiveness in the labor market, assistance in career planning and building of university students and graduates.

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Journal articles on the topic 'Trajectory enhancement'

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