1,895 research outputs found
Optimal three-dimensional impact time guidance with seeker's field-of-view constraint
No full textThis paper proposes a new three-dimensional optimal guidance law for impact time control with seeker's Field-of-View (FOV) constraint to intercept a stationary target. The proposed guidance law is devised in conjunction with the concept of biased Proportional Navigation Guidance (PNG). The guidance law developed leverages a nonlinear function to ensure the boundedness of velocity lead angle to cater to the seeker's FOV limit. It is proven that the impact time error is nullified in a finite-time under the proposed method. Additionally, the optimality of the biased command is theoretically analyzed. Numerical simulations confirm the superiority of the proposed method and validate the analytic findings. © 2020 Chinese Society of Aeronautics and Astronautics
Flame propagation in a converging tube
No full text학위논문(석사) - 한국과학기술원 : 기계공학전공, 2002.8, [ iv, 42 p ]한국과학기술원 : 기계공학전공
Three-dimensional biased proportional navigation guidance based on spatial rotation of predicted final velocity
No full textThis study presents the design of three-dimensional biased proportional navigation guidance laws for arrival at a stationary target along a desired direction based on spatial rotation of predicted final velocity vector. The focus is on full constructive derivation using vector-form expressions without introducing local representation of rotation such as Euler angles or quaternions. The proposed approach synthesises the bias command in the form of an angular velocity vector through realisation of the predictive control design philosophy, the direction which has been unexplored in a three-dimensional setting. The proposed approach avoids heuristic choices and approximations in the design process and hence overcomes the limitation of earlier studies. The vector-form design approach provides theoretical and practical advantages including rigour in derivation, clear geometric understandings about the problem provided by identification of the most effective direction for rotation of final velocity, independence from selection of a fixed coordinate system, avoidance of singularities in local representations, more direct trajectory shaping, and simple implementation
Energy-optimal waypoint-following guidance considering autopilot dynamics
No full textThis paper addresses the problem of energy-optimal waypoint-following guidance for an Unmanned Aerial Vehicle with the consideration of a general autopilot dynamics model. The proposed guidance law is derived as a solution of a linear quadratic optimal control problem in conjunction with a linearized kinematics model. The algorithm developed integrates path planning and following into a single step and is able to be applied to a general waypoint-following mission. Theoretical analysis reveals that previously suggested optimal point-to-point guidance laws are special cases of the proposed approach. Nonlinear numerical simulations clearly demonstrate the effectiveness of the proposed formulations
Minimum-effort waypoint-following guidance
No full textThis paper addresses the problem of minimum-effortwaypoint-following guidance with/without
arrival angle constraints of an Unmanned Aerial Vehicle. By utilizing a linearized kinematics
model, the proposed guidance laws are derived as the solutions of a linear quadratic optimal
control problem with an arbitrary number of terminal boundary constraints. Theoretical
analysis reveals that both optimal proportional navigation guidance and trajectory shaping
guidance are special cases of the proposed guidance laws. The key feature of the proposed
algorithms lies in their generic property. For this reason, the guidance laws developed can be
applied to general waypoint-following missions with an arbitrary number of waypoints and
an arbitrary number of arrival angle constraints. Nonlinear numerical simulations clearly
demonstrate the effectiveness of the proposed formulations
The general anesthesia experience of deletion 8p syndrome patient
No full textA deletion 8p syndrome is a relatively uncommon congenital disease characterized by mental retardation associated with multiple malformation that make anesthetic management a challenge. Anesthetic management of a patient with deletion 8p syndrome may pose a serious problem mainly from difficult tracheal intubation, aspiration complication and cardiac malformation. We experienced a case of 10 year-old boy with a deletion 8p syndrome who underwent appendectomy under the general anesthesia. Intubation was performed by video glidescope after unsuccessful attempt with Macintosh laryngoscope. A high arched palate, short neck, poor patient cooperation due to mental retardation and occasional autistic behaviour made airway management difficult. This case should alert anesthesiologists to the greater difficulties of managing patients with deletion 8p syndrome
sj-docx-1-tan-10.1177_17562864231218181 – Supplemental material for Effect of altered gene expression in lipid metabolism on cognitive improvement in patients with Alzheimer’s dementia following fecal microbiota transplantation: a preliminary study
No full textSupplemental material, sj-docx-1-tan-10.1177_17562864231218181 for Effect of altered gene expression in lipid metabolism on cognitive improvement in patients with Alzheimer’s dementia following fecal microbiota transplantation: a preliminary study by Jun-Seob Kim, Hyelim Park, Jung-Hwan Lee, Jongbeom Shin, Boram Cha, Kye Sook Kwon, Yong Woon Shin, Yerim Kim, YeoJin Kim, Jong Seok Bae, Ju-Hun Lee, Seok-Jin Choi, Tae Jung Kim, Sang-Bae Ko and Soo-Hyun Park in Therapeutic Advances in Neurological Disorders</p
Non-load-balance-dependent high efficiency single-inductor multiple-output (SIMO) DC-DC converters
No full textReview of data-driven computational guidance for unmanned aerospace vehicles
No full textThis paper explores the application of data-driven computational guidance in unmanned aerospace vehicles, emphasizing improving the optimality of guidance strategies through data-driven approaches. Unmanned aerospace vehicles are engineered to execute predetermined missions while adhering to a variety of physical and operational constraints. Both their design and operational strategies prioritize the efficient utilization of onboard resources. Data-driven methods can learn from data to develop well-trained neural networks that uncover underlying guidance patterns. These trained neural networks can rapidly generate optimal outputs in response to inputs with minimal computational cost. This characteristic of data-driven methods is particularly well-suited for guidance applications in scenarios with limited onboard computational resources. This paper reviews the state-of-the-art achievements in data-driven computational guidance. Simultaneously, we categorize these advancements based on the role of neural networks within the guidance system, referring to them as neural-end-to-end computational guidance and neural-assisted fixed-structure guidance, respectively. Additionally, the paper highlights several open problems and potential future research directions.
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