ZOOpt: Toolbox for Derivative-Free Optimization

Recent advances of derivative-free optimization allow efficient approximating the global optimal solutions of sophisticated functions, such as functions with many local optima, non-differentiable and non-continuous functions. This article describes the ZOOpt (https://github.com/eyounx/ZOOpt) toolbox that provides efficient derivative-free solvers and are designed easy to use. ZOOpt provides a Python package for single-thread optimization, and a light-weighted distributed version with the help of the Julia language for Python described functions. ZOOpt toolbox particularly focuses on optimization problems in machine learning, addressing high-dimensional, noisy, and large-scale problems. The toolbox is being maintained toward ready-to-use tool in real-world machine learning tasks

Cramer-Rao Bound Optimization for Active RIS-Empowered ISAC Systems

Integrated sensing and communication (ISAC), which simultaneously performs sensing and communication functions using the same frequency band and hardware platform, has emerged as a promising technology for future wireless systems. However, the weak echo signal received by the low-sensitivity ISAC receiver severely limits the sensing performance. Active reconfigurable intelligent surface (RIS) has become a prospective solution by situationally manipulating the wireless propagations and amplifying the signals. In this paper, we investigate the deployment of active RIS-empowered ISAC systems to enhance radar echo signal quality as well as communication performance. In particular, we focus on the joint design of the base station (BS) transmit precoding and the active RIS reflection beamforming to optimize the parameter estimation performance in terms of Cramer-Rao bound (CRB) subject to the service users' signal-to-interference-plus-noise ratio (SINR) requirements. An efficient algorithm based on block coordinate descent (BCD), semidefinite relaxation (SDR), and majorization-minimization (MM) is proposed to solve the formulated challenging non-convex problem. Finally, simulation results validate the effectiveness of the developed algorithm and the potential of employing active RIS in ISAC systems to enhance direct-of-arrival (DoA) estimation performance.Comment: 30 pages, 9 figures, submitted to IEEE journa

Predicted ΛΛˉ\Lambda\bar{\Lambda} and Ξ−Ξˉ+\Xi^-\bar{\Xi}^+ decay modes of the charmoniumlike Y(4230)Y(4230)

In this work, we predict the light hadronic decay channels $Y(4230)\to\Lambda\bar{\Lambda}$ and $\Xi^-\bar{\Xi}^+$ when treating the $Y(4230)$ as a vector charmonium state. By the hadronic loop mechanism, the branching ratios of the $Y(4230)\to\Lambda\bar{\Lambda}$ and $\Xi^-\bar{\Xi}^+$ processes are calculated. In addition, we discuss the possibility of carrying out the search for the signal of the $Y(4230)$ through $\Lambda\bar{\Lambda}$ and $\Xi^-\bar{\Xi}^+$ channels from the $e^+e^-$ annihilation. Assuming $Y(4230)$ exist in $\Lambda\bar{\Lambda}$ and $\Xi^-\bar{\Xi}^+$ channel, we also present the time-like electromagnetic form factors (EMFFs) at $\sqrt{s}=m_{Y(4230)}$.Comment: 8 pages, 9 figures and 2 table