1,699 research outputs found

    Inverse regression for longitudinal data

    Full text link
    Sliced inverse regression (Duan and Li [Ann. Statist. 19 (1991) 505-530], Li [J. Amer. Statist. Assoc. 86 (1991) 316-342]) is an appealing dimension reduction method for regression models with multivariate covariates. It has been extended by Ferr\'{e} and Yao [Statistics 37 (2003) 475-488, Statist. Sinica 15 (2005) 665-683] and Hsing and Ren [Ann. Statist. 37 (2009) 726-755] to functional covariates where the whole trajectories of random functional covariates are completely observed. The focus of this paper is to develop sliced inverse regression for intermittently and sparsely measured longitudinal covariates. We develop asymptotic theory for the new procedure and show, under some regularity conditions, that the estimated directions attain the optimal rate of convergence. Simulation studies and data analysis are also provided to demonstrate the performance of our method.Comment: Published in at http://dx.doi.org/10.1214/13-AOS1193 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org). With Correction

    Digital Transformations in Taiwanese TV Industry

    Get PDF
    In the past, TV was always regarded as an indispensable member of every family. Watching TV programs with the whole family was once one of the key consumer behaviors. However, with the development of technology, the digital wave and the invasion of Over-The-Top (OTT)platforms, consumer behavior has begun to undergo drastic changes. Mobile phones and tablets occupy most of our time. Multi-screens have long become the norm. According to the Digital Whirlpool report published by IMD in 2019: Due to the impact of digital convergence, digital disruption has already occurred in the media, entertainment, and telecommunications industries. If digital transformation is not carried out in time, the next five may be replaced by other new services . Observe that the number of cable TV subscribers in Taiwan has dropped from 5.23 million in 2017. With the influence of online platforms and online pirated content, it has fallen all the way to the current low of 4.83 million in 2021.Facing the changes in viewers’ viewing behaviors and the shift in TV advertising budgets in recent years, various TV stations have also provided solutions and actively transformed from internal thinking to external environments. TV stations such as TVBS, Eastern Broadcasting Company (EBC), Sanli TV and Ctitv have begun their digital transformation

    Cost-Sensitive Learning for Recurrence Prediction of Breast Cancer

    Get PDF
    Breast cancer is one of the top cancer-death causes and specifically accounts for 10.4% of all cancer incidences among women. The prediction of breast cancer recurrence has been a challenging research problem for many researchers. Data mining techniques have recently received considerable attention, especially when used for the construction of prognosis models from survival data. However, existing data mining techniques may not be effective to handle censored data. Censored instances are often discarded when applying classification techniques to prognosis. In this paper, we propose a cost-sensitive learning approach to involve the censored data in prognostic assessment with better recurrence prediction capability. The proposed approach employs an outcome inference mechanism to infer the possible probabilistic outcome of each censored instance and adopt the cost-proportionate rejection sampling and a committee machine strategy to take into account these instances with probabilistic outcomes during the classification model learning process. We empirically evaluate the effectiveness of our proposed approach for breast cancer recurrence prediction and include a censored-data-discarding method (i.e., building the recurrence prediction model by only using uncensored data) and the Kaplan-Meier method (a common prognosis method) as performance benchmarks. Overall, our evaluation results suggest that the proposed approach outperforms its benchmark techniques, measured by precision, recall and F1 score

    Security analysis of quantum key distribution with small block length and its application to quantum space communications

    Get PDF
    The security of real-world quantum key distribution (QKD) critically depends on the number of data points the system can collect in a fixed time interval. To date, state-of-the-art finite-key security analyses require block lengths in the order of 1E4 bits to obtain positive secret keys. This requirement, however, can be very difficult to achieve in practice, especially in the case of entanglement-based satellite QKD systems, where the overall channel loss can go up to 70 dB or more. Here, we provide an improved finite-key security analysis which can reduce the block length requirement by 14% to 17% for standard channel and protocol settings. In practical terms, this reduction could save entanglement-based satellite QKD weeks of measurement time and resources, thereby bringing space-based QKD technology closer to reality. As an application, we use the improved analysis to show that the recently reported Micius QKD satellite is capable of generating positive secret keys with a 1E−51E-5 security level.Comment: Revised draft; 5 pages, 1 figure. We warmly welcome comments/corrections, as well as suggestions for additional areas to stud

    Effect of temperature on the accumulation of marine biogenic gels in the surface microlayer near the outlet of nuclear power plants and adjacent areas in the Daya Bay, China

    Get PDF
    The surface microlayer (SML) in marine systems is often characterized by an enrichment of biogenic, gel-like particles, such as the polysaccharide-containing transparent exopolymer particles (TEP) and the protein-containing Coomassie stainable particles (CSP). This study investigated the distribution of TEP and CSP, in the SML and underlying water, as well as their bio-physical controlling factors in Daya Bay, an area impacted by warm discharge from two Nuclear power plants (Npp’s) and aquaculture during a research cruise in July 2014. The SML had higher proportions of cyanobacteria and of pico-size Chl a contrast to the underlayer water, particularly at the nearest outlet station characterized by higher temperature. Diatoms, dinoflagellates and chlorophyll a were depleted in the SML. Both CSP and TEP abundance and total area were enriched in the SML relative to the underlying water, with enrichment factors (EFs) of 1.5–3.4 for CSP numbers and 1.32–3.2 for TEP numbers. Although TEP and CSP showed highest concentration in the region where high productivity and high nutrient concertation were observed, EFs of gels and of dissolved organic carbon (DOC) and dissolved acidic polysaccharide (> 1 kDa), exhibited higher values near the outlet of the Npp’s than in the adjacent waters. The positive relation between EF’s of gels and temperature and the enrichment of cyanobacteria in the SML may be indicative of future conditions in a warmer ocean, suggesting potential effects on adjusting phytoplankton community, biogenic element cycling and air-sea exchange processe

    Pyrolysis of wild cyanophyta from Chaohu lake for bio-oil

    Get PDF
    To solve the environmental problems caused by the algae, pyrolysis experiment was studied to produce bio-oil with the wild cyanophyta from Chaohu lake for the first time. The results showed that the suitable temperature, carrier gas flow rate, and the smaller particle size were better for liquid products generation, the liquid (bio-oil) yield obtained maximum (66 %) at temperature of 450 oC, carried gas flow rate of 50 mL/min and particle size of less than 0.25 mm. The main ingredients of liquid product from cyanophyta pyrolysis consisted of hydrocarbons, nitrogenous compounds, acids and other organic compounds (such as alcohols, phenols esters and non-identified materials). Acid content was the highest and greatly affected by temperature. The content of hydrocarbons was about 15%
    • …
    corecore