A Unified Compression Framework for Efficient Speech-Driven Talking-Face Generation

Virtual humans have gained considerable attention in numerous industries, e.g., entertainment and e-commerce. As a core technology, synthesizing photorealistic face frames from target speech and facial identity has been actively studied with generative adversarial networks. Despite remarkable results of modern talking-face generation models, they often entail high computational burdens, which limit their efficient deployment. This study aims to develop a lightweight model for speech-driven talking-face synthesis. We build a compact generator by removing the residual blocks and reducing the channel width from Wav2Lip, a popular talking-face generator. We also present a knowledge distillation scheme to stably yet effectively train the small-capacity generator without adversarial learning. We reduce the number of parameters and MACs by 28$\times$ while retaining the performance of the original model. Moreover, to alleviate a severe performance drop when converting the whole generator to INT8 precision, we adopt a selective quantization method that uses FP16 for the quantization-sensitive layers and INT8 for the other layers. Using this mixed precision, we achieve up to a 19$\times$ speedup on edge GPUs without noticeably compromising the generation quality.Comment: MLSys Workshop on On-Device Intelligence, 2023; Demo: https://huggingface.co/spaces/nota-ai/compressed_wav2li

Analytic Solution for Fuel-Optimal Reconfiguration in Relative Motion

The current paper presents simple and general analytic solutions to the optimal reconfiguration of multiple satellites governed by a variety of linear dynamic equations. The calculus of variations is used to analytically find optimal trajectories and controls. Unlike what has been determined from previous research, the inverse of the fundamental matrix associated with the dynamic equations is not required for the general solution in the current study if a basic feature in the state equations is met. This feature is very common due to the fact that most relative motion equations are represented in the LVLH frame. The method suggested not only reduces the amount of calculations required, but also allows predicting the explicit form of optimal solutions in advance without having to solve the problem. It is illustrated that the optimal thrust vector is a function of the fundamental matrix of the given state equations, and other quantities, such as the cost function and the state vector during the reconfiguration, can be concisely represented as well. The analytic solutions developed in the current paper can be applied to most reconfiguration problems in linearized relative motions. Numerical simulations confirm the brevity and accuracy of the general analytic solutions developed in the current paper

Analytic Solution to Optimal Reconfigurations of Satellite Formation Flying in Circular Orbit under J2 Perturbation

This paper presents an analytic solution to the optimal reconfiguration problem of satellite formation flying in J2 orbital perturbation. Continuous and variable low-thrust accelerations are represented by the Fourier series, and initial and final boundary conditions are used to establish the constraints on the thrust functions. The thrust functions are implemented by optimal Fourier coefficients that minimize the cost during the maneuver. The analytic solution composed of these Fourier coefficients are simply represented in a closed form, and no approximation is needed. Numerical simulations are conducted to visualize and compare the results obtained in this paper with those of previous papers with no perturbations. The analytic solution developed in this paper is more accurate in that the general behavior of the optimal control history and reconfiguration trajectories are easily calculated even in the presence of the J2 potential disturbance. The analytic solution is useful for designing a reconfiguration controller for satellite formation flying under J2 orbital perturbation

Simple analytic solution to the optimal reconfigurations in general relative motions

peer reviewedThe current paper presents and examines simple analytic solutions to the fuel-optimal reconfiguration problem of multiple satellites governed by various relative equations of motion. The problem is addressed by solving a standard optimal control problem for a linear time-varying system. This paper shows that the optimal thrust vector is directly proportional to the fundamental matrix associated with the given state equations, and other quantities such as the cost function and the state vector during the reconfiguration can be concisely represented as well, if two basic assumptions are met. These two assumptions are very common due to the fact that most relative motion equations are represented in the LVLH frame. The method allows predicting the explicit form of optimal solutions in advance without having to solve the problem and we only need to determine coefficients to satisfy the boundary conditions. A numerical simulator is employed to confirm the brevity and the accuracy of the general analytic solutions developed in the current paper

Analytical Solution to Optimal Relocation of Satellite Formation Flying in Arbitrary Elliptic Orbits

The current paper presents and examines a general analytical solution to the optimal reconfiguration problem of satellite formation flying in an arbitrary elliptic orbit. The proposed approach does not use any simplifying assumptions regarding the eccentricity of the reference orbit. For the fuel optimal reconfiguration problem, continuous and variable low-thrust accelerations can be represented by the Fourier series and summed into closed-form solutions. Initial and final boundary conditions are used to establish the constraints on the thrust functions. The analytical solution can be implicated by the Fourier coefficients that minimize propellant usage during the maneuver. This solution is found that compares favorably with numerical simulations. Also, this analytical solution is very useful for designing a reconfiguration controller for satellite formation flying in a general elliptic orbit

Application of Analytic Solution in Relative Motion to Spacecraft Formation Flying in Elliptic Orbit

The current paper presents application of a new analytic solution in general relative motion to spacecraft formation flying in an elliptic orbit. The calculus of variations is used to analytically find optimal trajectories and controls for the given problem. The inverse of the fundamental matrix associated with the dynamic equations is not required for the solution in the current study. It is verified that the optimal thrust vector is a function of the fundamental matrix of the given state equations. The cost function and the state vector during the reconfiguration can be analytically obtained as well. The results predict the form of optimal solutions in advance without having to solve the problem. Numerical simulation shows the brevity and the accuracy of the general analytic solutions developed in the current paper