Browsing by Author "Yang, Yang"

Now showing 1 - 7 of 7
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    A Class of Stochastic Path-Dependent Models and Controls
    (2024-09-19) Yang, Yang; Qiu, Jinniao; Ware, Antony; Sezer, Deniz; Swishchuk, Anatoliy; Liao, Wenyuan; Huang, Minyi
    This thesis explores controlled stochastic path-dependent differential systems and their applications in stock and energy markets. We first focus on a class of path-dependent stochastic optimal control problems within an infinite-dimensional framework. Our primary contribution is proving that the value function serves as the unique viscosity solution to the corresponding infinite-dimensional stochastic path-dependent Hamilton-Jacobi equation. Then, we investigate the introduction of path-dependent features in stochastic volatility models. The price-storage dynamic is studied in natural gas markets. We propose a novel stochastic path-dependent volatility model that incorporates path-dependence into both price volatility and storage increments. Chapter 1 focuses on the stochastic optimal control problem for infinite-dimensional differential systems that incorporate both path-dependence and measurable randomness. Unlike deterministic path-dependent cases, the value function emerges as a random field over the path space, characterized by a stochastic path-dependent Hamilton-Jacobi (SPHJ) equation. We propose a notion of viscosity solution and demonstrate that the value function is the unique viscosity solution to the associated SPHJ equation. Chapter 2 and 3 explores price-storage dynamics in natural gas markets. We introduce a novel stochastic path-dependent volatility model that incorporates path-dependence in both price volatility and storage increments. Model calibrations are performed for both price and storage dynamics. Additionally, we address the pricing problem for discrete-time swing options using the dynamic programming principle and propose a deep learning-based method for numerical approximations. A numerical algorithm is presented, accompanied by a convergence analysis of the deep learning approach. Chapter 4 outlines future research directions in stochastic path-dependent Hamilton-Jacobi-Bellman (HJB) equations, stochastic volatility models, mean field games and stochastic path-dependent filtering problems.
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    Development of a Nano-Composite Coating Technology for Improvement of Carbon Steel Pipe to Erosion-Corrosion in Oil Sands Slurry
    (2013-09-13) Yang, Yang; Cheng, Yufeng (Frank)
    Erosion-corrosion (E-C) has constituted an essential threat to the integrity of oil sands slurry hydrotransport system. To improve the resistance of carbon steel pipes to E-C in oil sands slurry, a composite coating technology has been developed by electrolytic deposition in this research. Parametric effects on the structure and properties of the coating were investigated in order to fabricate high performance coatings. It is found that the electrodepositing parameters, such as the concentration of SiC nano-particles in bath electrolyte, cathodic current density, current pattern and temperature, affect remarkably the particle deposition which relates directly with the coating performance. Furthermore, the parameters in pulse current electrodeposition also affect the properties and performance of the prepared coatings. Enhancements of the corrosion resistance and micro-hardness of the coating have been obtained at a low duty cycle and high frequency, which result in an increased amount of SiC particles in the coating. The nucleation and early stage growth mechanism of the composite coating on the steel substrate was determined by cyclic voltammetry, chronoamperometry current transient measurements and atomic force microscopy (AFM) characterization. A mixed instantaneous and progressive mechanism is followed during electrodeposition under low cathodic overpotentials. At high overpotentials, it switches to the instantaneous mechanism. An empirical model based on the modified Guglielmi’s model was developed to enable quantification and prediction of the co-depositing rate of SiC particles with Ni-Co coating during pulse electrodeposition. To understand the E-C behavior of pipe steel in oil sands slurry and the performance of the fabricated coating for E-C resistance, parametric effects, including the sand concentration, flow velocity and impact angle, on the E–C behavior of bare and coated steels were studied. It is demonstrated that erosion components are the dominant contributors to E–C in oil sands slurry, while the contribution of corrosion components is slight. The developed Ni-Co-SiC nano-composite coating shows a higher resistance to E-C than the base steel.
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    An Essay on Bilateral Relations and Trade Between Canada and China
    (2016-09) Yang, Yang; Beaulieu, Eugene
    China is the second largest economy in the world and Canada’s second largest trading partner. According to the government of Canada, the two countries generally maintain a co-operative relationship. However, Canada’s economic co-operation with China is still limited; the share of Canadian exports to mainland China was only 1.08 per cent in 2014 and 4.11 per cent in 2015, while China supplied 12.26 per cent of total Canadian imports in 2015. Since 2012, Canada‘s exports to China have declined. Also, foreign investment between Canada and China is limited and experienced a downward trend from 2013-2015. There is a huge potential for Canada to expand its market share in China. Based on facts and accredited sources, this thesis intends to study whether Canada should further enhance its political and economic ties with China, and to identify what the opportunities, challenges and barriers are to Canada-China bilateral trade. The research here mainly covers foreign investment and the most promising trade sectors with high economic complementarities, including agriculture, clean technology and natural resources. The findings indicate that it is mutually beneficial for Canada and China to deepen their economic ties.
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    ING1 Impacts Ovarian Cancer by Altering EMT
    (2019-08-30) Yang, Yang; Riabowol, Karl T.; Bonni, Shirin; Rancourt, Derrick E.; Muruve, Daniel A.
    The INhibitor of Growth (ING) proteins are type II tumour suppressors that regulate epigenetic state and transcription by recruiting various chromatin-modifying complexes to chromatin. INGs are involved in multiple cellular processes such as DNA repair, apoptosis and cellular senescence. In this study, we investigated the potential role of ING1 in inhibiting the epithelial-mesenchymal transition (EMT) program that suppresses cancer metastasis and identifies the mechanism of how ING1 regulates gene transcription, as well as its clinical implication in epithelial ovarian cancer. Our analyses revealed that ING1 epigenetically regulates the transcription machinery of the EMT program through binding to the promoter region of Twist1, the critical gene encoding transcription factor (TF) that induce EMT. Subsequently, ING1 promoted the expression of epithelial cell markers, including E-cadherin, while suppressing the expression of mesenchymal markers such as N-cadherin. ING1 antagonized TGF-β or EGF induced EMT and inhibited cancer cell invasion and migration in a Twist1-dependent manner. Integration of ChIP-seq and RNA-seq data revealed the overall genomic binding characteristics of ING1 and its candidate target genes. Gene ontology (GO) and pathway analyses indicated that the genes targeted by ING1 were involved in diverse physiological processes and pathways, mostly associated with the EMT program. The bioinformatical analysis revealed the ING1 binding motif sequence, showing that ING1 recognized target genes through the TEAD family of transcription factors and their co-factor, YAP1, to further influence gene expression. Lastly, we found that high ING1 protein expression was associated with p16 and ARID1A levels and predicted better DSS in ovarian clear cell carcinoma (OCCC). Our data also suggested that high ING1/low N-cadherin expression predicts favourable disease-specific survival (DSS) in epithelial ovarian cancer. These data provide evidence that as a tumour suppressor, ING1 can impact ovarian cancer development through modulating the EMT process and play an essential role in regulating ovarian cancer chemoresistance. In summary, by downregulating the EMT-TF expression and hence and EMT program, ING1 suppresses tumour cell invasion and cancer metastasis. Global genomic profiling revealed new insights into ING1 biology and provided justification for further exploring ING1 functions. This study has also provided critical pre-clinical data that could help establish ING1 as a prognostic and therapeutic agent for ovarian cancer.
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    Regulatory mechanisms mediated by va14 NKT cells in type 1 diabetes
    (2009) Wang, Jianxiong; Yang, Yang; Santamaria, Pere
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    The regulation of Va14 NKT Cells
    (2007) Cheng, Lu; Yang, Yang
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    Upadacitinib Rapidly Improves Patient-Reported Outcomes in Atopic Dermatitis: 16-Week Results from Phase 3 Clinical Trials (Measure Up 1 and 2)
    (2024-05-02) Simpson, Eric L.; Prajapati, Vimal H.; Leshem, Yael A.; Chovatiya, Raj; de Bruin-Weller, Marjolein S.; Ständer, Sonja; Pink, Andrew E.; Calimlim, Brian M.; Lee, Wan-Ju; Teixeira, Henrique; Ladizinski, Barry; Hu, Xiaofei; Yang, Yang; Liu, Yingyi; Liu, Meng; Grada, Ayman; Platt, Andrew M.; Silverberg, Jonathan I.
    Abstract Introduction Atopic dermatitis (AD) is characterized by intense itch and other symptoms that negatively impact quality of life (QoL). This study evaluates the effect of upadacitinib (an oral selective Janus kinase inhibitor) monotherapy on patient-reported outcomes (PROs) among adults and adolescents with moderate-to-severe AD over 16 weeks. Methods This integrated analysis of the double-blind, placebo-controlled periods of phase 3 monotherapy clinical trials Measure Up 1 (NCT03569293) and Measure Up 2 (NCT03607422) assessed itch (Worst Pruritus Numerical Rating Scale [WP-NRS] and SCORing Atopic Dermatitis [SCORAD]), skin pain and symptom severity (AD Symptom Scale), symptom frequency (Patient-Oriented Eczema Measure), sleep (AD Impact Scale [ADerm-IS] and SCORAD), daily activities and emotional state (ADerm-IS), QoL (Dermatology Life Quality Index [DLQI] and Children’s DLQI), mental health (Hospital Anxiety and Depression Scale), and patient impressions (Patient Global Impression of Severity, Patient Global Impression of Change, and Patient Global Impression of Treatment). Results Data from 1683 patients (upadacitinib 15 mg, n = 557; upadacitinib 30 mg, n = 567; placebo, n = 559) were analyzed. A greater proportion of patients receiving upadacitinib versus placebo experienced improvements in itch (≥ 4-point improvement on WP-NRS) by week 1 (upadacitinib 15 mg, 11.2%; upadacitinib 30 mg, 17.7%; placebo, 0.5%; P < 0.001), with response rates sustained through week 16 (upadacitinib 15 mg, 47.1%; upadacitinib 30 mg, 59.8%; placebo, 10.4%; P < 0.001). Improvements were similar for PROs assessing skin pain/symptoms, sleep, daily activities, QoL, emotional state, mental health, and patient impressions of disease severity and treatment. Responses generally improved rapidly (within 1–2 weeks), increased through weeks 4–6, and were maintained through week 16. Conclusions Once-daily oral upadacitinib monotherapy improved response rates across PROs compared with placebo. Upadacitinib therapy resulted in rapid, sustained improvements in PROs measuring symptom burden and QoL in adults and adolescents with moderate-to-severe AD. Trial Registration ClinicalTrials.gov identifiers, NCT03569293 and NCT03607422.