University of Houston
  • Houston, TX, United States
Recent publications
This work considers the path-following problem for Unmanned Aerial System (UAS) in which an online remote control station computes and sends control input signals to the vehicle over an adverse communication network. In that network configuration, the cyber attackers and malicious eavesdroppers are prone to erode the UAS's safety properties such as operational security and information privacy. To guarantee these properties, we introduce a secure model predictive control (MPC) framework for achieving both optimal and safe path-following performance. The unique feature of this framework is that it can simultaneously address all the adversaries occurring in both remote station and network transmission links. Then, an encrypted MPC law is designed using an effective encoding scheme and the Paillier cryptography scheme. It is shown that the closed-loop stability can be guaranteed under the proposed MPC law. Simulation studies of UAS path-following are conducted to validate the effectiveness of the proposed framework.
We have developed buffer architecture on a nonmetallic substrate with a length over 4 cm for epitaxial growth of a rare earth barium copper oxide (REBCO) film. We used a 40 μm thick, flexible yttria-stabilized zirconia (YSZ) as a suitable nonmetallic substrate for high-frequency applications because of its good dielectric properties, low thermal conductivity, and flexibility. The YSZ substrate was planarized to ∼1 nm roughness, facilitating the growth of high-quality, biaxially-textured magnesium oxide (MgO) by ion beam-assisted deposition (IBAD) followed by magnetron-sputter-deposited homo-epitaxial MgO and LaMnO3 (LMO) layers. The LMO films on flexible YSZ, with an out-of-plane texture of 3.1° and an in-plane texture of 6.7°, served as a good template for high-quality REBCO film growth. 350-nm-thick REBCO films grown by metal-organic chemical vapor deposition (MOCVD) were characterized using scanning hall probe microscopy for uniformity in critical current density ( J <sub xmlns:mml="" xmlns:xlink="">c</sub> ) at 77 K. Surface resistivity values of the REBCO films on flexible YSZ at 8–8.3 GHz and 20–75 K were found to be on par with that of high-quality REBCO films on the sapphire substrate. An inverse correlation was found between the J <sub xmlns:mml="" xmlns:xlink="">c</sub> and surface resistivity of the REBCO films on a flexible YSZ substrate.
Organizational culture continues to be a decisive factor for the success of hospitality firms. Drawing from the theory of work adjustment, this study focuses on hospitality organizational culture and examines its impacts on hospitality employees' job satisfaction, organizational citizenship behaviors, service recovery performance, and intention to leave. Using survey methodology , 210 hotel employees in Turkey provided survey data. The results demonstrated significant effects of hospitality culture on turnover, service recovery performance, organizational citizenship behavior, and job satisfaction as a significant mediator. The findings stress the importance of a strong hospitality culture to positively influence employees' job attitude, and job performance.
Developing non‐precious catalysts with long‐term catalytic durability and structural stability under industrial conditions is the key to practical alkaline anion exchange membrane (AEM) water electrolysis. Here we propose an energy‐saving approach to synthesize defect‐rich iron nickel oxyhydroxide for stability and efficiency toward the oxygen evolution reaction (OER). Benefiting from in situ cation exchange, the nanosheet‐nanoflake‐structured catalyst is homogeneously embedded in, and tightly bonded to, its substrate, making it ultrastable at high current densities. Experimental and theoretical calculation results reveal that the introduction of Ni in FeOOH reduces the activation energy barrier for the catalytic reaction and that the purposely created oxygen defects not only ensure the exposure of active sites and maximize the effective catalyst surface but also modulate the local coordination environment and chemisorption properties of both Fe and Ni sites, thus lowering the energy barrier from *O to *OOH. Consequently, the optimized d‐(Fe,Ni)OOH catalyst exhibits outstanding catalytic activity with long‐term durability under both laboratory and industrial conditions. The large‐area d‐(Fe,Ni)OOH||NiMoN pair requires 1.795 V to reach a current density of 500 mA cm ⁻² at an absolute current of 12.5 A in an AEM electrolyzer for overall water electrolysis, showing great potential for industrial water electrolysis. This article is protected by copyright. All rights reserved
提 要 本文以美国某一大学中文项目的发展为例, 从三个方面探讨了近三十年来北美中文教学的状况: (1) 机遇中的发展, (2) 面临的挑战, (3) 应对策略。这三十年我们经历了之前生源的空前高涨, 以及近期由于国际形势变化特别是全球疫情的出现影响到中文课注册人数、尤其是中文主修人数的锐减。面对机遇和挑战, 本文在给休斯顿大学的中文研究项目定向定位的同时, 结合近年来对北美中文教育发展的调查、对学习动机学习目的的系列研究, 总结了应对策略。建立在研究结果和学生反思与评价的基础上, 本文针对课程设计、教学要求, 以及如何服务多元背景不同学习动机的学生等方面, 提出建立高质量严要求的中文项目。教师需要营造一个从自己学生的需求特点出发、教学互动性强的课堂氛围, 以帮助学生获得所学内容的实用感与正面的学习体验。这是学生继续修中文课的前提。
Purpose The purpose of this study was to compare child language assessment practices of speech-language pathologists (SLPs) working in school and nonschool settings to determine if their place of employment impacts the diagnostic decision-making process. Method School-based SLPs (e.g., direct service providers employed in preschool and/or K–12 schools; n = 382) and non–school-based SLPs (e.g., direct service providers employed in private practices, university clinics, and/or medical settings; n = 147) completed a web-based questionnaire. The questionnaire examined the types, frequency, and perceived importance of specific assessment tools and potential workplace factors that may impact their diagnostic decision-making process. Results Both school-based and non–school-based SLPs reported using a combination of assessment tools when evaluating children with potential language disorders. School-based SLPs tended to rank the frequency of use and importance of most assessment tools similarly, while non–school-based SLPs ranked interviews as the most frequently used and most important assessment tool. Statistically significant group differences indicated that school-based SLPs ranked the frequency of use and importance of standardized testing higher compared to their non–school-based counterparts. Also, school-based SLPs rated employment-based factors impacting diagnostic decision making higher compared to non–school-based SLPs. Conclusions SLPs practicing in school-based settings seem to handle more employment-based factors that impact independent diagnostic decision making than SLPs working in different employment settings when assessing children for potential language disorders. Clinical recommendations are provided, and implications for implementation-based assessment research in child language are discussed.
Assisted Outpatient Treatment (AOT) is a court-mandated program intended to engage adults with serious mental illness who have challenges with voluntary treatment adherence. AOT programs are designed to promote outpatient treatment participation, reduce emergency care, and decrease justice involvement. Research has found AOT programs to be effective in reducing hospitalizations and justice involvement. Yet, concerns have been raised, including limiting individual autonomy and self-determination and overrepresentation of individuals from BIPOC backgrounds. This article describes the evolution the AOT Houston Model. Through applying the social work lens, this innovative model builds on AOT strengths and addresses limitations. The Houston AOT Model has five goals guided by the core tenets of client empowerment and self-determination. This Model prioritizes six elements including housing, employment, access to public benefits, transportation, service continuity, and care coordination/communication. Implications for practice and policy are presented with strategies for successful implementation of comprehensive AOT programs in other jurisdictions.
This essay argues that secular is an important keyword for Victorian studies because it foregrounds the particularity of universal concepts. Victorian narratives of secularization and colonial regimes of religious toleration can all be shown to have roots in the Protestant conception of religion as private individual belief and voluntary association. They therefore raise the question of how and whether such political conceptions might transcend their particularist origins. To make this point I begin by exploring the difference between secularism and secularization as critical terms. I then suggest how the recent wave of work on secularism has illuminated the link between the two—namely, by showing how attempts to imagine a secular world in fact depend upon specific ideas of what religion is and where it belongs.
Time-frequency analysis techniques offer valuable insights into the dynamic characteristics of non-stationary signals, making them suitable for diagnosing faults in rotating machinery operating under variable speed conditions. However, extracting meaningful features from time-frequency representations (TFRs) faces challenges due to energy spreading caused by complex modes and background noise. To address this issue, this paper introduces a novel technique called the Synchro-Reassigned Extracting Transform (SRET). The SRET uses instantaneous frequency and group delay operators to extract and reassign energy coefficients simultaneously in both the frequency and time directions, enhancing the sharpness of TFRs. Theoretical analysis reveals limitations of the synchroextracting transform (SET) when analyzing signals with both slowly and rapidly varying features, which the proposed SRET effectively overcomes. To optimize computational efficiency, the paper presents a discrete implementation algorithm for SRET. The effectiveness of SRET in analyzing time-varying signals and diagnosing bearing faults is demonstrated through simulations and two sets of bearing vibration data. Additionally, the application of SRET in processing vibration signals from a wind turbine gearbox highlights its potential for fault diagnosis in rotating machinery.
The proliferation of novel infotainment services such as Virtual Reality(VR)-based services has fundamentally changed the existing mobile networks. These bandwidth-hungry services expanded at a tremendously rapid pace, thus, generating a burden of data traffic in the mobile networks. To cope with this issue, one can use Multi-access Edge Computing (MEC) to bring the resource to the edge. By doing so, we can release the burden of the core network by taking the communication, computation, and caching resources nearby the end-users (UEs). Nevertheless, due to the vast adoption of VR-enabled devices, MEC resources might be insufficient in peak times or dense settings. To overcome these challenges, we propose a system model where the service provider (SP) might rent Unmanned Area Vehicles (UAVs) from UAV service providers (USPs) to serve as micro-based stations (UBSs) that expand the service area and improve the spectrum efficiency. In which, UAV can pre-cached certain sets of VR-based contents and serve UEs via air-to-ground (A2G) communication. Furthermore, future intelligent devices are capable of 5G and B5G communication interfaces, and thus, they can communicate with UAVs via A2G links. By doing so, we can significantly reduce a considerable amount of data traffic in mobile networks. In order to successfully enable such kinds of services, an attractive incentive mechanism is required. Therefore, we propose a contract theory-based incentive mechanism for UAV-assisted MEC in VR-based infotainment services, in which the MEC offers an amount reward to a UAV for serving as a UBS in a specific location for certain time slots. We then derive an optimal contract-based scheme with individual rationality and incentive compatibility conditions. The numerical findings show that our proposed approach outperforms the Linear Pricing (LP) technique and is close to the optimal solution in terms of social welfare. Additionally, our proposed scheme significantly enhanced the fairness of utility for UAVs in asymmetric information problems.
Satellite instruments have the most potential of capturing trace gas variability as they continually observe the atmosphere and its composition over wide regions. Yet the increasingly large data size of satellite products poses a challenge for their use as traditional data processing methods (e.g., averaging) may not be effective to extract the spatiotemporal variability without prior knowledge of an emission source’s spatial and temporal behavior, such as location, time, and plume shape. Here, an agile clustering algorithm entitled CLustering of Atmospheric Satellite Products (CLASP) is presented to identify the spatiotemporal variability of trace gases captured in satellite observations. We find the knowledge discovery method for large datasets, clustering, is suited for identifying the variability of trace gases in satellite observations, as such CLASP is rooted in density‐based clustering methods. CLASP detects features from satellite observations and identifies their spatial, magnitude, and temporal axis leading to a better understanding of the spatiotemporal variability of atmospheric trace gases. To test the applicability of CLASP, the algorithm is applied to TROPOMI NO 2 observations illustrating some of its different capabilities. Implementing CLASP for event identification, capturing plume variability, and source detection, CLASP identified wildfires, observed disruptions from COVID‐19 lockdown restrictions, and detected irregular emissions from oil and gas operations.
We estimate the US prevalence of uncorrectable visual impairment in 2050 accounting for the changing distribution of both age and myopia. Age projections of the US population (from an estimated total of 379 million in 2050), were taken from the US census website. The distribution of myopia, by severity, was calculated from literature-derived prevalence estimates of 58.4% (≤ − 0.50 D, 2050 projection) and 33.1% (≤ − 1.00 D, 1999–2004 estimate) to provide predicted and conservative estimates, respectively. Uncorrectable visual impairment as a function of age and refractive error was modelled by multiple linear regression. Finally, the likely number of individuals in the US with visual impairment in 2050 was calculated. For a projected myopia prevalence of 58.4%, 222 million are projected to be myopic and 48 million will have high myopia (− 5 D or worse). The projected total number with uncorrectable visual impairment is 11.4 million of which 4.9 million cases (43%) of visual impairment will be directly attributed to increased risk of eye disease associated with myopia. For a projected myopia prevalence of 33.1%, 8.9 million are projected to have uncorrectable visual impairment of which 2.4 million cases (27%) will be directly attributed to myopia. It is predicted that between 27 and 43% of uncorrectable visual impairment in the US population in 2050 will be directly attributable to myopia. Failure to account for the increasing prevalence of myopia among the aging population leads to a substantial underestimate of the prevalence of visual impairment.
Tissue transglutaminase (TG2) is a widely distributed multifunctional protein involved in a broad range of cellular and metabolic functions carried out in a variety of cellular compartments. In addition to transamidation, TG2 also functions as a Gα signaling protein, a protein disulphide isomerase (PDI), a protein kinase and a scaffolding protein. In the nucleus, TG2 modifies histones and transcription factors. The PDI function catalyzes the trimerization and activation of heat shock factor-1 in the nucleus and regulates the oxidation state of several mitochondrial complexes. Cytosolic TG2 modifies proteins by the addition of serotonin or other primary amines and in this way affects cell signaling. Modification of protein bound glutamines reduces ubiquitin-dependent proteasomal degradation. At the cell membrane, TG2 is associated with GPCRs, where it functions in transmembrane signaling. TG2 is also found in the extracellular space where it functions in protein cross-linking and extracellular matrix stabilization. Of particular importance in transglutaminase research are recent findings concerning the role of TG2 in gene expression, protein homeostasis, cell signaling, autoimmunity, inflammation, and hypoxia. Thus, TG2 performs a multitude of functions in multiple cellular compartments making it one of the most versatile cellular proteins. Additional evidence links TG2 with multiple human diseases including preeclampsia, hypertension, cardiovascular disease, organ fibrosis, cancer, neurodegenerative diseases and celiac disease. In conclusion, TG2 provides a multifunctional and multisite response to physiological stress.
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10,683 members
Amit K Gupta
  • Department of Pharmacological and Pharmaceutical Sciences
Melisa Martinez-Paniagua
  • Department of Chemical & Biomolecular Engineering
Ali Rad
  • William A. Brookshire Department of Chemical and Biomolecular Engineering
Daniel Anthony Martinez
  • Department of Mechanical Engineering
4800 Calhoun Road, 77004, Houston, TX, United States
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