Fixed angle inverse scattering in the presence of a Riemannian metric

We consider a fixed angle inverse scattering problem in the presence of a known Riemannian metric. First, assuming a no caustics condition, we study the direct problem by utilizing the progressing wave expansion. Under a symmetry assumption on the metric, we obtain uniqueness and stability results in the inverse scattering problem for a potential with data generated by two incident waves from opposite directions. Further, similar results are given using one measurement provided the potential also satisfies a symmetry assumption. This work extends the results of [23,24] from the Euclidean case to certain Riemannian metrics.Comment: 27 page

Single-realization recovery of a random Schr\"odinger equation with unknown source and potential

In this paper, we study an inverse scattering problem associated with the stationary Schr\"odinger equation where both the potential and the source terms are unknown. The source term is assumed to be a generalised Gaussian random distribution of the microlocally isotropic type, whereas the potential function is assumed to be deterministic. The well-posedness of the forward scattering problem is first established in a proper sense. It is then proved that the rough strength of the random source can be uniquely recovered, independent of the unknown potential, by a single realisation of the passive scattering measurement. We develop novel techniques to completely remove a restrictive geometric condition in our earlier study [25], at an unobjectionable cost of requiring the unknown potential to be deterministic. The ergodicity is used to establish the single realization recovery, and the asymptotic arguments in our analysis are based on techniques from the theory of pseudo-differential operators and the stationary phase principle.Comment: 28 page

REGULATION OF DOPAMINE TRANSPORTER SUBCELLULAR LOCALIZATION AND TRAFFICKING

Dopamine transporter (DAT) controls dopamine (DA) neurotransmission by clearing synaptically released DA. The substrate uptake function of DAT is regulated by its subcellular localization. We propose that DAT localization and trafficking are regulated by its molecular conformation and interactions of the transporter with lipids and membrane-associated proteins. We used several experimental approaches and two DAT mutants to demonstrate that accumulation of DAT in plasma membrane protrusions, such as myosin X-dependent filopodia, requires an outward facing (OF) conformation of the DAT molecule. Furthermore, using targeted plasma membrane depletion of phosphatidylinositol 4,5-bisphosphate (PIP2), a lipid that is highly enriched in the plasma membrane and proposed to bind DAT, we demonstrated that PIP2 is necessary for protein kinase C (PKC)-stimulated DAT endocytosis but not essential for maintaining steady-state levels of DAT at the cell surface. Therefore, these results suggest that PIP2 is essential for clathrin-mediated PKC-stimulated DAT endocytosis and PIP2 is not involved in the retention of DAT at the cell surface. In search of DAT interactors regulating its plasma membrane retention, distribution, subcellular localization, and function, we used quantitative mass spectrometry analysis to identify proteins that are co-precipitated with DAT isolated from the mouse striatum. A novel interaction of DAT with Gαo, the α subunit of Go proteins that are coupled to dopamine D2 receptor and other receptors, was confirmed by reciprocal co- immunoprecipitation and western blotting in mouse striatum and a heterologous expression system. While structure-functional analysis of this interaction will be performed in the future studies, our biochemical and morphological analyses led to the hypothesis that DAT-Gαo interaction may mediate the regulatory effects of D2 auto-receptors on DAT localization and activity. In summary, our data suggest that the localization of DAT in filopodia, which is regulated by DAT conformation and possibly DAT-Gαo interaction but not DAT interaction with PIP2, is the primary mechanisms of the retention of functional DAT at the cell surface

RIS-Aided MIMO Systems with Hardware Impairments: Robust Beamforming Design and Analysis

Reconfigurable intelligent surface (RIS) has been anticipated to be a novel cost-effective technology to improve the performance of future wireless systems. In this paper, we investigate a practical RIS-aided multiple-input-multiple-output (MIMO) system in the presence of transceiver hardware impairments, RIS phase noise and imperfect channel state information (CSI). Joint design of the MIMO transceiver and RIS reflection matrix to minimize the total average mean-square-error (MSE) of all data streams is particularly considered. This joint design problem is non-convex and challenging to solve due to the newly considered practical imperfections. To tackle the issue, we first analyze the total average MSE by incorporating the impacts of the above system imperfections. Then, in order to handle the tightly coupled optimization variables and non-convex NP-hard constraints, an efficient iterative algorithm based on alternating optimization (AO) framework is proposed with guaranteed convergence, where each subproblem admits a closed-form optimal solution by leveraging the majorization-minimization (MM) technique. Moreover, via exploiting the special structure of the unit-modulus constraints, we propose a modified Riemannian gradient ascent (RGA) algorithm for the discrete RIS phase shift optimization. Furthermore, the optimality of the proposed algorithm is validated under line-of-sight (LoS) channel conditions, and the irreducible MSE floor effect induced by imperfections of both hardware and CSI is also revealed in the high signal-to-noise ratio (SNR) regime. Numerical results show the superior MSE performance of our proposed algorithm over the adopted benchmark schemes, and demonstrate that increasing the number of RIS elements is not always beneficial under the above system imperfections.Comment: 30 pages, 8 figures. This paper has been submitted to IEEE journal for possible publicatio

Pedestrian Attribute Editing for Gait Recognition and Anonymization

As a kind of biometrics, the gait information of pedestrians has attracted widespread attention from both industry and academia since it can be acquired from long distances without the cooperation of targets. In recent literature, this line of research has brought exciting chances along with alarming challenges: On the positive side, gait recognition used for security applications such as suspect retrieval and safety checks is becoming more and more promising. On the negative side, the misuse of gait information may lead to privacy concerns, as lawbreakers can track subjects of interest using gait characteristics even under face-masked and clothes-changed scenarios. To handle this double-edged sword, we propose a gait attribute editing framework termed GaitEditor. It can perform various degrees of attribute edits on real gait sequences while maintaining the visual authenticity, respectively used for gait data augmentation and de-identification, thereby adaptively enhancing or degrading gait recognition performance according to users' intentions. Experimentally, we conduct a comprehensive evaluation under both gait recognition and anonymization protocols on three widely used gait benchmarks. Numerous results illustrate that the adaptable utilization of GaitEditor efficiently improves gait recognition performance and generates vivid visualizations with de-identification to protect human privacy. To the best of our knowledge, GaitEditor is the first framework capable of editing multiple gait attributes while simultaneously benefiting gait recognition and gait anonymization. The source code of GaitEditor will be available at https://github.com/ShiqiYu/OpenGait