E-Business Oriented Optimal Online Auction Design

Online auctions, in the absence of spatial, temporal and geographic constraints, provide an alternative supply chain channel for the distribution of goods and services. This channel differs from the common posted-price mechanism that is typically used in the retail sector. In consumer-oriented markets, buyers can now experience the thrill of ‘winning’ a product, potentially at a bargain, as opposed to the typically more tedious notion of ‘buying’ it. Sellers, on the other hand, have an additional channel to distribute their goods, and the opportunity to liquidate rapidly aging goods at greater than salvage values. The primary facilitator of this phenomenon is the widespread adoption of electronic commerce over an open-source, ubiquitous Internet Protocol (IP) based network. In this paper, we derive an optimal bidding strategy in sequential auctions that incorporates option value assessment. Furthermore, we establish that our optimal bidding strategy is tractable since it is independent of the bidding strategies of other bidders in the current auction and is only dependent on the option value assessmen

Applications of Projection Pursuit in Functional Data Analysis: Goodness-of- fit, Forecasting, and Change-point Detection

Dimension reduction methods for functional data have been avidly studied in recent years. However, existing methods are primarily based on summarizing the data by their projections into principal component subspaces, namely the functional principal component analysis (fPCA). While fPCA could be effective sometimes, in this thesis we show with both real and synthetic data examples some pitfalls of this approach, especially when the components of interest of the functional data are orthogonal to the leading principal components. In multivariate data analysis, a possible alternative, the projection pursuit technique, was proposed by Kruskal (1972) and Friedman and Tukey (1974). In this thesis, we extend the idea of projection pursuit to functional data analysis. We develop several new computational tools needed to implement the high-dimensional projection pursuit. We apply this functional projection pursuit technique to three problems: (i) normality test for functional data; (ii) forecasting the functional time series; and (iii) change point detection for functional data. For each problem, a simulation study and several data analyses are provided to show the advantages of our proposed method to existing methods in the literature that mostly based on principal component analysis

Inverse-designed broadband low-loss grating coupler on thick lithium-niobate-on-insulator platform

A grating coupler on 700-nm-thick Z-cut lithium-niobate-on-insulator platform with high coupling efficiency, large bandwidth, and high fabrication tolerance is designed and optimized by inverse design method. The optimized grating coupler is fabricated with a single set of e-beam lithography and etching process, and it is experimentally characterized to possess peak coupling efficiency of -3.8 dB at 1574.93 nm, 1-dB bandwidth of 71.7 nm, and 3-dB bandwidth of over 120 nm.Comment: 8 pages, 4 figure

Photoelectrochemical Reduction of CO2 over Graphene-Based Composites: Basic Principle, Recent Progress, and Future Perspective

面对日益严重的化石能源消耗和温室效应问题,二氧化碳还原正成为一个重要的全球性研究课题,其通过消耗二氧化碳来生成可用于能源供应的产物。光电催化技术; 同时利用光能和外部电压,是一种用于二氧化碳还原的可行且有效的途径。因为石墨烯具有增强二氧化碳吸附和促进光生电子转移的特性能够提升石墨烯基复合电极; 的性能,所以引入石墨烯用于调优光电催化二氧化碳还原体系已经引起了广泛关注。本篇综述详细陈述了石墨烯基复合材料应用于光电二氧化碳还原的基本原理,电; 极制备方法以及目前的研究进展。我们也对这个蓬勃发展的领域未来可能会遇到的机遇和挑战进行了展望,同时提出了潜在可行的革新策略用于提升光电二氧化碳还; 原方面的研究。In response to aggravated fossil resources consuming and greenhouse effect, CO2 reduction has become a globally important scientific issue because this method can be used to produce value-added feedstock for application in alternative energy supply. Photoelectrocatalysis, achieved by combining optical energy and external electrical bias, is a feasible and promising system for CO2 reduction. In particular, applying graphene in tuning photoelectrochemical CO2 reduction has aroused considerable attention because graphene is advantageous for enhancing CO2 adsorption, facilitating electrons transfer, and thus optimizing the performance of graphene-based composite electrodes. In this review, we elaborate the fundamental principle, basic preparation methods, and recent progress in developing a variety of graphene-based composite electrodes for photoelectrochemical reduction of CO2 into solar fuels and chemicals. We also present a perspective on the opportunities and challenges for future research in this booming area and highlight the potential evolution strategies for advancing the research on photoelectrochemical CO2 reduction.National Natural Science Foundation of China [U1463204, 20903023,; 21173045]; Award Program for Minjiang Scholar Professorship; Natural; Science Foundation of Fujian Province [2012J06003, 2017J07002];; Independent Research Project of State Key Laboratory of Photocatalysis; on Energy and Environment [2014A05]; first Program of Fujian Province; for Top Creative Young Talents; Open Research Project of State Key; Laboratory of Physical Chemistry of Solid Surfaces of Xiamen University; [201519]; Program for Returned High-Level Overseas Chinese Scholars of; Fujian provinc

Tropical storm-induced turbulent mixing and chlorophyll-a enhancement in the continental shelf southeast of Hainan Island

AbstractBased on moored observations and remote sensing data in July and August 2005, energy sources for enhancing turbulent mixing and possible mechanisms of phytoplankton bloom in the continental shelf southeast of Hainan Island under the influence of Washi, a fast-moving and weak tropical storm, are analyzed in this paper. Observations show that strong near-inertial internal waves were generated by the rapidly changing wind stress and the near-inertial energy was dissipated quickly across the thermocline. The strong turbulent mixing associated with the near-inertial baroclinic shear instability occurred with maximum eddy diffusivity above 3.2×10−4m2s−1, and the surface chlorophyll-a (Chl-a) concentration after the storm increased by 22.2%. The Chl-a concentration augment was inferred to be an upper ocean biophysical response to the enhanced near-inertial turbulent mixing which could increase the upward nutrient flux into the surface low eutrophic zone during the passage of Washi

Synthesized spatiotemporal mode-locking and photonic flywheel in multimode mesoresonators

Dissipative Kerr soliton (DKS) frequency combs&mdash;also known as microcombs&mdash;have arguably created a new field in cavity nonlinear photonics, with a strong cross-fertilization between theoretical, experimental, and technological research. Spatiotemporal mode-locking (STML) not only adds new degrees of freedom to ultrafast laser technology, but also provides new insights for implementing analogue computers and heuristic optimizers with photonics. Here, we combine the principles of DKS and STML to demonstrate the STML DKS by developing an unexplored ultrahigh-quality-factor Fabry&ndash;P&eacute;rot (FP) mesoresonator based on graded index multimode fiber (GRIN-MMF). Complementing the two-step pumping scheme with a cavity stress tuning method, we can selectively excite either the eigenmode DKS or the STML DKS. Furthermore, we demonstrate an ultralow noise microcomb that enhances the photonic flywheel performance in both the fundamental comb linewidth and DKS timing jitter. The demonstrated fundamental comb linewidth of 400 mHz and DKS timing jitter of 500 attosecond (averaging times up to 25&thinsp;&mu;s) represent improvements of 25&times; and 2.5&times;, respectively, from the state-of-the-art. Our results show the potential of GRIN-MMF FP mesoresonators as an ideal testbed for high-dimensional nonlinear cavity dynamics and photonic flywheel with ultrahigh coherence and ultralow timing jitter. &nbsp;</p

Combined strategies with PARP inhibitors for the treatment of BRCA wide type cancer

Genomic instability stands out as a pivotal hallmark of cancer, and PARP inhibitors (PARPi) emerging as a groundbreaking class of targeted therapy drugs meticulously crafted to inhibit the repair of DNA single-strand breaks(SSB) in tumor cells. Currently, PARPi have been approved for the treatment of ovarian cancer, pancreatic cancer, breast cancer, and prostate cancer characterized by homologous recombination(HR) repair deficiencies due to mutations in BRCA1/2 or other DNA repair associated genes and acquiring the designation of breakthrough therapy. Nonetheless, PARPi exhibit limited efficacy in the majority of HR-proficient BRCA1/2 wild-type cancers. At present, the synergistic approach of combining PARPi with agents that induce HR defects, or with chemotherapy and radiotherapy to induce substantial DNA damage, significantly enhances the efficacy of PARPi in BRCA wild-type or HR-proficient patients, supporting extension the use of PARPi in HR proficient patients. Therefore, we have summarized the effects and mechanisms of the combined use of drugs with PARPi, including the combination of PARPi with HR defect-inducing drugs such as ATRi, CHKi, HR indirectly inducing drugs like VEGFRi, CDKi, immune checkpoint inhibitors and drugs instigating DNA damage such as chemotherapy or radiotherapy. In addition, this review discusses several ongoing clinical trials aimed at analyzing the clinical application potential of these combined treatment strategies

Riemannian Surface on Carbon Anodes Enables Li-Ion Storage at −35 °C

Since sluggish Li$^{+}$ desolvation leads to severe capacity degradation of carbon anodes at subzero temperatures, it is urgently desired to modulate electron configurations of surface carbon atoms toward high capacity for Li-ion batteries. Herein, a carbon-based anode material (O-DF) was strategically synthesized to construct the Riemannian surface with a positive curvature, which exhibits a high reversible capacity of 624 mAh g$^{-1}$ with an 85.9% capacity retention at 0.1 A g$^{-1}$ as the temperature drops to −20 °C. Even if the temperature drops to −35 °C, the reversible capacity is still effectively retained at 160 mAh g$^{-1}$ after 200 cycles. Various characterizations and theoretical calculations reveal that the Riemannian surface effectively tunes the low-temperature sluggish Li$^{+}$ desolvation of the interfacial chemistry via locally accumulated charges of non-coplanar sp$^{x}$ (2 < x < 3) hybridized orbitals to reduce the rate-determining step of the energy barrier for the charge-transfer process. Ex-situ measurements further confirm that the sp$^{x}$-hybridized orbitals of the pentagonal defect sites should denote more negative charges to solvated Li$^{+}$ adsorbed on the Riemannian surface to form stronger Li–C coordinate bonds for Li$^{+}$ desolvation, which not only enhances Li-adsorption on the curved surface but also results in more Li$^{+}$ insertion in an extremely cold environment