52 research outputs found
AdaptVarLM: A linear regression model for covariate-dependent non-constant error variance
No full textIn biological research, traditional multiple regression models assume homoscedasticity — constant variance of error terms — an assumption that is difficult to maintain in complex biological data. This thesis introduces AdaptVarLM, a novel linear regression model specialized in dealing with non-constant error variance dependent on one covariate. AdaptVarLM integrates an auxiliary linear relationship between the logarithmic variance of the error term and a specific explanatory variable, and uses maximum likelihood estimation (MLE) in the iterative updating process to improve the parameter estimation accuracy. By modelling non-constant error variance, AdaptVarLM outperforms the traditional regression model in capturing the complex variability inherent in biological data. Applying to the study of Alzheimer's disease, AdaptVarLM detects genetically linked genes associated with the disease and error variance. The results of analyzing both bulk and single-cell data validate the effectiveness of AdaptVarLM in detecting significant genes.Graduate2025-08-2
Researches on inverse simulation’s applications in teleoperation rendezvous and docking based on hyper-ellipsoidal restricted model predictive control for inverse simulation structure
No full textWuzhen pian 悟真篇 also known as “Essay on the [Immediate] Awakening to Truth”, “Chapters on Awakening to Perfection”
No full textWuzhen pian (DZ 263.26, j. 26-30 and DZ 1017, j. 18, “Essay on the [Immediate] Awakening to Truth.” Also translated as “Chapters on Awakening to Perfection.” Its preface is dated to 1075, and its postface is dated to 1078) is a seminal Daoist inner alchemical work that underpins inner alchemy as the essential method for immortal cultivation. Inner alchemy (neidan, which literally means internal cinnabar, 內丹) refers to a range of esoteric teachings and practices derived from diverse theories including but not limited to correlative cosmology, laboratory alchemy (also known as outer alchemy, waidan, 外丹) and the teachings of Yijing 易經 (Book of Changes). Unlike the laboratory alchemy practitioners, who aim to achieve immortality by consuming magical potions made of minerals and herbs, those who practice inner alchemy focus on meditation. In meditative practices, they visualize the human body as a cauldron that refines the internal vital forces including essence (jing 精), pneuma (qi 氣), and spirit (shen 神) to produce an internal elixir, which will help them transcend. Wuzhen pian’s attributed author, Zhang Boduan 張伯端 (987?—1082), was worshipped as the founder of the Southern Lineage (Nanzong 南宗) of inner alchemy. The work was read as a commentary on the Zhouyi cantong qi 周易參同契 (Token for the Kinship of the Three According to the Zhouyi, DZ 999 and DZ 1004)—the earliest Chinese treatise on laboratory alchemy and granted equal importance in the teaching of inner alchemy. Most sections in Cantong qi were written as tetrasyllabic or pentasyllabic rhymed verses. A few other sections adopt the Sao style or prose style. Influenced by Cantong qi, Wuzhen pian also adopts the form of poetry. However, most sections in Wuzhen pian were septasyllabic quatrains or regulated verses, which are poetic forms that became dominant in the Tang dynasty (618—907). It also includes a section of song lyrics (ci 詞), a genre that became mainstream in the Song dynasty (906—1279). The Wuzhen pian’s adoption of the new poetic forms not only reveals the author’s mastery of poetry but also exemplifies the Daoist treatises’ achievement in introducing new contents to the literary tradition. The Wuzhen pian originally comprised eighty-one verses, which are divided into three sections: the first section consists of sixteen septasyllabic regulated verses that focus on the idea of “two times eight” mechanism, which embodies the dichotomy of yin and yang that functions with hexagrams; the second section includes sixty-four septasyllabic quatrains that incorporate the concept of the hexagram in the Book of Changes and the last pentasyllabic poem eulogizes the ideal of the Great Unity (taiyi 太一). Later, two additional sections were added: one section comprises twelve pieces of song lyrics following the tunes of Western River Moon (xijiangyue 西江月); the other contains thirty-two poems that elaborate on cultivation through Buddhist subjects. According to Zhang Boduan’s summary in the postface, the contents range from the teachings about “the ranking of vessels, the weight of medical ingredients, and the control of fire-phasing” to the method for distinguishing “the superiority and inferiority, existence and nonexistence, and auspicious and ominous.” The text’s highly esoteric and symbolic language indicates that oral instruction by a master was required during the learning process. Inevitably, its obscurity also led to various interpretations, stirring much debate among later commentators. While Wuzhen pian includes certain guidance for sexual techniques, commentators tended to disapprove of such contents. Instead, they emphasized the teaching of inner alchemy and the text’s relation to the Book of Changes. Two sets of Wuzhen pian’s inner alchemical concept were considered essential in later receptions. First, it inherited the theory of dual cultivation of nature and life (xingming shuangxiu 性命雙修) from the Zhong-Lü tradition, a Daoist meditative tradition that was active during the late Tang and regarded refining one’s nature (xing 性) and prolonging life (ming 命) as equally important. Second, it absorbs the theory refining essence, pneuma, and spirit, which was promoted by the Daoist master Chen Tuan’s 陳摶 (871—989), making these elements the key components for producing the internal cinnabar. Although the alleged author Zhang Boduan was active during the eleventh century, Wuzhen pian did not gain much attention until the mid-twelfth century. During the 1160s, many commentaries begin to appear, and the text itself becomes available in many editions. The edition that collects the earliest commentaries is a five juan version titled Wuzhen pian jizhu 悟真篇集註, which is mentioned in Zhizhai shulu jieti 直齋書錄解題, one of the most influential private book collection catalog composed by the Southern Song literatus Chen Zhensun 陳振孫 (1179－1262). Some major commentators and compilers include Weng Baoguang’s 翁葆光 (c. 12th century), Xia Yuanding 夏元鼎 (c. early 13th century), and Chen Zhixu 陳致虛 (b. 1290). The Taoist Canon: A Historical Companion to the Daozang edited by Kristofer Schipper and Franciscus Verellen provides a comprehensive list of Wuzhen pian editions and inspired works. About the later transmission of the treatise, the Wuzhen pian probably influenced the Northen Lineage of inner alchemy, which was represented by the Quanzhenjiao 全真教 (Teaching of Complete Perfection). Louis Komjathy argues that the Quanzhen tradition merged with the Southern Lineage on the eve of the fall of the Song dynasty. It is very likely that the Quanzhen tradition also engaged the inner alchemical theories established by Wuzhen pian.Non UBCUnreviewedGraduat
Inverse simulation system for evaluating handling qualities during rendezvous and docking
No full textThe traditional method used for handling qualities assessment of manned space vehicles is too time-consuming to meet the requirements of an increasingly fast design process. In this study, a rendezvous and docking inverse simulation system to assess the handling qualities of spacecraft is proposed using a previously developed model- predictive-control architecture. By considering the fixed discrete force of the thrusters of the system, the inverse model is constructed using the least squares estimation method with a hyper-ellipsoidal restriction, the contin- uous control outputs of which are subsequently dispersed by pulse width modulation with sensitivity factors introduced. The inputs in every step are deemed constant parameters, and the method could be considered as a general method for solving nominal, redundant, and insufficient inverse problems. The rendezvous and docking inverse simulation is applied to a nine-degrees-of-freedom platform, and a novel handling qualities evaluation scheme is established according to the operation precision and astronauts' workload. Finally, different nominal trajectories are scored by the inverse simulation and an established evaluation scheme. The scores can offer theoretical guidance for astronaut training and more complex operation missions
Failure effect analysis and reconfiguration of thrusters based on inverse simulation of manually controlled RVD
No full textFault analysis of man-in-loop systems is a valuable issue worthy of being studied, especially in projects including high risk and high investment like manned space missions. Spacecraft sometimes must have the fault tolerance to complete their task even after errors occurring. Inverse simulation was previously proved to achieve manually rendezvous and docking (RVD) successfully. The aim of this paper is to demonstrate the potential applications of inverse simulation to undertake the thruster fault analysis and reconfigurations in manned RVD mission. Firstly, the inverse simulation system is established in a model predicted control structure. Then, the astronauts' operational strategy is analyzed through the thruster fault simulation, and an operational rate factor is proposed to assess the failure risk. In addition, the original configuration is transformed to strengthen the resistance under consideration of the fault tolerance. The comparative results indicate that the modified configuration can improve the performance effectively and then guarantee the success of the mission
Error Analysis and Modification of Inverse Simulation for Manually Controlled Rendezvous and Docking
No full textRecent advances on N-acetylneuraminic acid: Physiological roles, applications, and biosynthesis
No full textN-Acetylneuraminic acid (Neu5Ac), the most common type of Sia, generally acts as the terminal sugar in cell surface glycans, glycoconjugates, oligosaccharides, lipo-oligosaccharides, and polysaccharides, thus exerting numerous physiological functions. The extensive applications of Neu5Ac in the food, cosmetic, and pharmaceutical industries make large-scale production of this chemical desirable. Biosynthesis which is associated with important application potential and environmental friendliness has become an indispensable approach for large-scale synthesis of Neu5Ac. In this review, the physiological roles of Neu5Ac was first summarized in detail. Second, the safety evaluation, regulatory status, and applications of Neu5Ac were discussed. Third, enzyme-catalyzed preparation, whole-cell biocatalysis, and microbial de novo synthesis of Neu5Ac were comprehensively reviewed. In addition, we discussed the main challenges of Neu5Ac de novo biosynthesis, such as screening and engineering of key enzymes, identifying exporters of intermediates and Neu5Ac, and balancing cell growth and biosynthesis. The corresponding strategies and systematic strategies were proposed to overcome these challenges and facilitate Neu5Ac industrial-scale production
Coverage Analysis Tool Design in Object-Oriented Astronautical Simulation Software Using Plugin
No full textExploring the Spatial Spillovers of Digital Finance on Urban Innovation and Its Synergy with Traditional Finance
No full textResearch on the driving role of digital finance in urban innovation is scarce. Most existing literature focuses on whether digital or traditional finance contributes more to innovation, ignoring the spatial spillover effect of digital finance and failing to explore whether digital finance complements traditional finance in promoting innovation. Moreover, current studies focus on the provincial dimension but elaborate very little on the implications of BRI node cities. This study fills in the gaps by focusing on the spatial spillover effects of digital finance on urban innovation and complementary functions of traditional finance. It applies the spatial Durbin model to 26 China BRI node cities from 2013 to 2020. The results indicated that digital finance has a significant positive effect on the innovation level of these cities, suggesting that digital and traditional finance systems are complementary in promoting innovation. Moreover, the evidence of spatial spillover proves that innovations in node cities influence neighboring regions. This paper contributes to the interaction between digital finance and urban innovation with new insights. It also fills the literature gap by underlining the spatial dynamics rather than traditional panel approaches. The results are useful for policymakers in harnessing financial mechanisms for innovation and economic growth. Doi: 10.28991/ESJ-2025-09-01-024 Full Text: PD
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