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347 results on '"Liu, Boya"'

1. Stable determination of the first order perturbation of the biharmonic operator from partial data

Author

Liu, Boya and Selim, Salem

Subjects
Mathematics - Analysis of PDEs, 35R30, 35J40
Abstract

We consider an inverse boundary value problem for the biharmonic operator with the first order perturbation in a bounded domain of dimension three or higher. Assuming that the first and the zeroth order perturbations are known in a neighborhood of the boundary, we establish log-type stability estimates for these perturbations from a partial Dirichlet-to-Neumann map. Specifically, measurements are taken only on an arbitrarily small open subsets of the boundary.

Published
2024

2. A novel high-titer, bifunctional lentiviral vector for autologous hematopoietic stem cell gene therapy of sickle cell disease.

Author

Hart, Kevyn, Liu, Boya, Brown, Devin, Campo-Fernandez, Beatriz, Tam, Kevin, Orr, Katherine, Hollis, Roger, Brendel, Christian, Williams, David, and Kohn, Donald

Subjects
BCL11A, anti-sickling hemoglobin, gene therapy, hematopoietic stem cells, lentiviral vector, shmiR, sickle cell disease
Abstract

A major limitation of gene therapy for sickle cell disease (SCD) is the availability and access to a potentially curative one-time treatment, due to high treatment costs. We have developed a high-titer bifunctional lentiviral vector (LVV) in a vector backbone that has reduced size, high vector yields, and efficient gene transfer to human CD34+ hematopoietic stem and progenitor cells (HSPCs). This LVV contains locus control region cores expressing an anti-sickling βAS3-globin gene and two microRNA-adapted short hairpin RNA simultaneously targeting BCL11A and ZNF410 transcripts to maximally induce fetal hemoglobin (HbF) expression. This LVV induces high levels of anti-sickling hemoglobins (HbAAS3 + HbF), while concurrently decreasing sickle hemoglobin (HbS). The decrease in HbS and increased anti-sickling hemoglobin impedes deoxygenated HbS polymerization and red blood cell sickling at low vector copy per cell in transduced SCD patient CD34+ cells differentiated into erythrocytes. The dual alterations in red cell hemoglobins ameliorated the SCD phenotype in the SCD Berkeley mouse model in vivo. With high titer and enhanced transduction of HSPC at a low multiplicity of infection, this LVV will increase the number of patient doses of vector from production lots to decrease costs and help improve accessibility to gene therapy for SCD.

Published
2024

5. Stability estimates for an inverse boundary value problem for biharmonic operators with first order perturbation from partial data

Author

Liu, Boya

Subjects
Mathematics - Analysis of PDEs, 35R30, 35J40
Abstract

In this paper we study an inverse boundary value problem for the biharmonic operator with first order perturbation. Our geometric setting is that of a bounded simply connected domain in the Euclidean space of dimension three or higher. Assuming that the inaccessible portion of the boundary is flat, and we have knowledge of the Dirichlet-to-Neumann map on the complement, we prove logarithmic type stability estimates for both the first and the zeroth order perturbation of the biharmonic operator.

Published
2023
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9. Recovery of a time-dependent potential in hyperbolic equations on conformally transversally anisotropic manifolds

Author

Liu, Boya, Saksala, Teemu, and Yan, Lili

Subjects
Mathematics - Analysis of PDEs, 35R30, 35L05, 58J45
Abstract

We study an inverse problem of determining a time-dependent potential appearing in the wave equation in conformally transversally anisotropic manifolds of dimension three or higher. These are compact Riemannian manifolds with boundary that are conformally embedded in a product of the real line and a transversal manifold. Under the assumption of the attenuated geodesic ray transform being injective on the transversal manifold, we prove the unique determination of time-dependent potentials from the knowledge of a certain partial Cauchy data set., Comment: arXiv admin note: text overlap with arXiv:2306.10442

Published
2023

11. Partial data inverse problem for hyperbolic equation with time-dependent damping coefficient and potential

Author

Liu, Boya, Saksala, Teemu, and Yan, Lili

Subjects
Mathematics - Analysis of PDEs, 35R30, 35L05, 58J45
Abstract

We study an inverse problem of determining a time-dependent damping coefficient and potential appearing in the wave equation in a compact Riemannian manifold of dimension three or higher. More specifically, we are concerned with the case of conformally transversally anisotropic manifolds, or in other words, compact Riemannian manifolds with boundary conformally embedded in a product of the Euclidean line and a transversal manifold. With an additional assumption of the attenuated geodesic ray transform being injective on the transversal manifold, we prove that the knowledge of a certain partial Cauchy data set determines time-dependent damping coefficient and potential uniquely., Comment: arXiv admin note: text overlap with arXiv:1702.07974 by other authors

Published
2023

12. Three travel time inverse problems on simple Riemannian manifolds

Author

Ilmavirta, Joonas, Liu, Boya, and Saksala, Teemu

Subjects
Mathematics - Differential Geometry, 53C21, 53C24, 53C80, 86A22
Abstract

We provide new proofs based on the Myers-Steenrod theorem to confirm that travel time data, travel time difference data and the broken scattering relations determine a simple Riemannian metric on a disc up to the natural gauge of a boundary fixing diffeomorphism. Our method of the proof leads to a Lipschitz-type stability estimate for the first two data sets in the class of simple metrics.

Published
2022

34. Stability estimates in a partial data inverse boundary value problem for biharmonic operators at high frequencies

Author

Liu, Boya

Subjects
Mathematics - Analysis of PDEs, Mathematical Physics, 35R30, 35J40
Abstract

We study the inverse boundary value problems of determining a potential in the Helmholtz type equation for the perturbed biharmonic operator from the knowledge of the partial Cauchy data set. Our geometric setting is that of a domain whose inaccessible portion of the boundary is contained in a hyperplane, and we are given the Cauchy data set on the complement. The uniqueness and logarithmic stability for this problem were established in [37] and [7], respectively. We establish stability estimates in the high frequency regime, with an explicit dependence on the frequency parameter, under mild regularity assumptions on the potentials, sharpening those of [7].

Published
2019
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38. Global identifiability of low regularity fluid parameters in acoustic tomography of moving fluid

Author

Liu, Boya

Subjects
Mathematics - Analysis of PDEs, Mathematical Physics
Abstract

We are concerned with inverse boundary problems for first order perturbations of the Laplacian, which arise as model operators in the acoustic tomography of a moving fluid. We show that the knowledge of the Dirichlet--to--Neumann map on the boundary of a bounded domain in $\mathbb{R}^n$, $n\ge 3$, determines the first order perturbation of low regularity up to a natural gauge transformation, which sometimes is trivial. As an application, we recover the fluid parameters of low regularity from boundary measurements, sharpening the regularity assumptions in the recent results of [1] and [3]. In particular, we allow some fluid parameters to be discontinuous.

Published
2018
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44. Enhanced hydrogen evolution performance of twinned Mn0.65Cd0.35S with Zn-doped cadmium selenide under visible light irradiation.

Author

Liu, Boya, Shi, Suili, Wang, Congcong, Wang, Guorong, and Jin, Zhiliang

Subjects
*ELECTRON-hole recombination, *ENERGY conversion, *CADMIUM sulfide, *METAL sulfides, *METAL fabrication
Abstract

The cadmium manganese sulfide, despite being recognized as a highly efficient photocatalytic semiconductor for hydrogen evolution, faces significant challenges in terms of charge recombination when used solely as a catalyst for photocatalytic hydrogen production. The construction of heterojunction photocatalysts is regarded as one of the effective strategies to enhance the efficiency of photocatalytic hydrogen production. In this work, Zn-doped CdSe was adopted to enhance the photocatalytic active sites of the twinned Mn 0.65 Cd 0.35 S. As results, the photocatalytic hydrogen evolution of Zn–CdSe-1/T-MCS-40 can reach approximately 47447.15 μmol g−1 after 5 h, representing a 15 times increase compared to Mn 0.65 Cd 0.35 S. Besides, the hydrogen evolution rate shows almost no significant attenuation after four consecutive cycles (20 h). The significant achievement can be largely attributed to the successful construction of an S-scheme heterojunction of Zn – CdSe-1/T-MCS-40, which effectively minimized the charge transfer distance and suppressed the recombination of photo-generated electron-hole pairs. Additionally, the incorporation of Zn-doped CdSe significantly expands the response range to visible light, thereby providing a conceptual framework for advancing the design of solar-to-chemical energy conversion and effectively guiding the fabrication of metal sulfide-based photocatalytic heterojunctions. • Zn doping broadens the light absorption range of CdSe. • Zn–CdSe is coupled with T-MCS to form the S-scheme heterojunction. • The photocatalytic rate of Zn–CdSe-1/T-MCS-40 exhibits a 15 enhancement compared to Mn 0.65 Cd 0.35 S. • The separation of photogenerated carrier is accelerated by the construction of S-scheme heterojunction. [ABSTRACT FROM AUTHOR]

Published
2024
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48. LoPhy: A Resilient and Fast Covert Channel Over LoRa PHY

Author

Liu, Boya, Gu, Chaojie, He, Shibo, and Chen, Jiming

Abstract

Covert channel, which can break the logical protections of the computer system and leak confidential or sensitive information, has long been considered a security issue in the network research community. However, recent research has shown that cooperative agents can use the “covert” channel to augment the communication of legitimate applications, rather than by adversaries seeking to compromise computer security. This further broadens the potential applications of covert channels. Despite this, the design and implementation of covert channels in the context of Low Power Wide Area Networks (LPWANs) have not been widely discussed. Current state-of-the-art uses On-off keying (OOK) on LoRa PHY to create a covert channel, but this channel has limited transmission distance and capacity. In this paper, we propose LoPhy, a resilient and fast covert channel over LoRa physical layer (PHY). LoPhy uses the Chirp Spreading Spectrum (CSS) modulation scheme to increase its resilience and explore the trade-off between the covert channel’s capacity and the legitimate channel’s resilience. We implement the proposed covert channel on off-the-shelf devices and software-defined radios and show that LoPhy achieves a 0.57% bit error rate at a distance of $700\,\text {m}$ with slight impact on legitimate channel’s performance. Moreover, we present two applications enabled by LoPhy to demonstrate the potential of LoPhy. Compared with the state-of-the-art, LoPhy brings up to $18\times $ reduction of bit errors and $63\times $ gain on noise resilience.

Published
2024
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