978 research outputs found

    Machine Learning-based Indoor Positioning Systems Using Multi-Channel Information

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    The received signal strength indicator (RSSI) is a metric of the power measured by a sensor in a receiver. Many indoor positioning technologies use RSSI to locate objects in indoor environments. Their positioning accuracy is significantly affected by reflection and absorption from walls, and by non-stationary objects such as doors and people. Therefore, it is necessary to increase transceivers in the environment to reduce positioning errors. This paper proposes an indoor positioning technology that uses the machine learning algorithm of channel state information (CSI) combined with fingerprinting. The experimental results showed that the proposed method outperformed traditional RSSI-based localization systems in terms of average positioning accuracy up to 6.13% and 54.79% for random forest (RF) and back propagation neural networks (BPNN), respectively

    Machine Learning-based Indoor Positioning Systems Using Multi-Channel Information

    Get PDF
    The received signal strength indicator (RSSI) is a metric of the power measured by a sensor in a receiver. Many indoor positioning technologies use RSSI to locate objects in indoor environments. Their positioning accuracy is significantly affected by reflection and absorption from walls, and by non-stationary objects such as doors and people. Therefore, it is necessary to increase transceivers in the environment to reduce positioning errors. This paper proposes an indoor positioning technology that uses the machine learning algorithm of channel state information (CSI) combined with fingerprinting. The experimental results showed that the proposed method outperformed traditional RSSI-based localization systems in terms of average positioning accuracy up to 6.13% and 54.79% for random forest (RF) and back propagation neural networks (BPNN), respectively

    Chinese Herbal Medicine Therapy and the Risk of Mortality for Chronic Hepatitis B Patients with Concurrent Liver Cirrhosis: a Nationwide Population-Based Cohort Study

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    Chronic hepatitis B (CHB) is increasingly recognized as a public health problem in Taiwan. After affected patients are diagnosed with contaminant liver cirrhosis (LC), adverse clinical outcomes, especially death, are common. This study aimed to investigate the effect of Chinese herbal medicine (CHM), an essential branch of Traditional Chinese medicine (TCM), on the mortality risk among CHB patients with contaminant LC. This longitudinal cohort study used the Taiwanese National Health Insurance Research Database to identify 1522 patients 20–70 years of age with newly diagnosed CHB with LC during 1998–2007. Among them, 508 (33.37%) had received CHM products after the onset of CHB (CHM users), and the remaining 1014 patients (66.63%) were designated as a control group (non-CHM users). All enrollees were followed until the end of 2012 to determine deaths during the study period. We applied the Cox proportional hazards regression model to compute the hazard ratio for the association of CHM use and the subsequent risk of death. During the follow-up period, 156 CHM users and 493 non-CHM users died. After controlling for potential confounders, CHM users were found to have a significantly reduced risk of death compared with non-CHM users by 56%, and the effect was predominantly observed among those treated with CHM for \u3e 180 days. CHM therapy lowered the risk of death among CHB patients with contaminant LC, which supported CHM might provide further treatment options for those with chronic liver diseases

    Benthic Fluxes of Dissolved Organic Carbon from Gas Hydrate Sediments in the Northern South China Sea

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    Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 µmol m−2 d−1 (on average ~321 µmol m−2 d−1 which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 x 106 mol y-1, is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters

    High Yield of Wax Ester Synthesized from Cetyl Alcohol and Octanoic Acid by Lipozyme RMIM and Novozym 435

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    Wax esters are long-chain esters that have been widely applied in premium lubricants, parting agents, antifoaming agents and cosmetics. In this study, the biocatalytic preparation of a specific wax ester, cetyl octanoate, is performed in n-hexane using two commercial immobilized lipases, i.e., Lipozyme® RMIM (Rhizomucor miehei) and Novozym® 435 (Candida antarctica). Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1–5 h), reaction temperature (45–65 °C), substrate molar ratio (1–3:1), and enzyme amount (10%–50%) on the yield of cetyl octanoate. Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme® RMIM and Novozym® 435, respectively. The optimum conditions for synthesis of cetyl octanoate by both lipases are established and compared. Novozym® 435 proves to be a more efficient biocatalyst than Lipozyme® RMIM

    Hepatitis B virus infection among pregnant women in Taiwan: Comparison between women born in Taiwan and other southeast countries

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    <p>Abstract</p> <p>Background</p> <p>Taiwan's national vaccination program has successfully decreased the prevalence of hepatitis B infection after twenty years of implementation and might be indirectly beneficial to the second generation. In this study, we compared the hepatitis B infection status of two groups: pregnant Taiwanese women and other Southeast Asian women, who because they had immigrated later in life to Taiwan by marriage to a Taiwanese man, had not been exposed to that vaccination program to evaluate the effect of hepatitis vaccination program on women of child-bearing age and further explored the potential impact of immigration on the hepatitis B public health policy in Taiwan.</p> <p>Methods</p> <p>Data was collected from 10,327 women born in Taiwan and 1,418 women born in other Southeast Asian countries, both groups receiving prenatal examinations at Fooyin University Hospital between 1996 and 2005. The results of serum hepatitis B s-Antigen (HBsAg) and hepatitis B e-Antigen (HBeAg) tests and other demographic data were obtained by medical chart review.</p> <p>Results</p> <p>The pregnant women from Taiwan had a higher HBsAg positive rate (15.5%) but lower HBeAg(+)/HBsAg(+) ratio (32.1%) than the women from other countries (8.9% and 52.4%). For those born before July, 1984, the period of no national vaccination program, Taiwanese women had a higher HBsAg positive rate than other Southeast Asian women (15.7% vs. 8.4%), but for women born after that day and before June 1986, the period of vaccination for high risk newborns, the HBsAg positive rates found to be slightly lower for Taiwanese women than for other Southeast Asian women (11.4% vs. 12.3%) and the difference was more significant (3.1% vs. 28.6%) after June 1986, the period of vaccination for all newborns. While the HBeAg(+)/HBsAg(+) ratios decreased with age in both groups, they were consistently higher in women from other Southeast Asian countries than in women born in Taiwan after age 20.</p> <p>Conclusion</p> <p>In Taiwan, the neonatal vaccination program that was implemented in 1984 has successfully reduced hepatitis B infection among pregnant women in present day, and is likely to indirectly prevent hepatitis B infection in the next generation. However, the increasing number of pregnant women from other Southeast Asian countries without a national neonatal vaccination program or with a program that was introduced later than the one in Taiwan will likely lessen the positive impact of this program and should be further assessed.</p

    Differential Gene Expression in Response to Papayaringspot virus Infection in Cucumis metuliferus UsingcDNA- Amplified Fragment Length PolymorphismAnalysis

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    A better understanding of virus resistance mechanisms can offer more effective strategies to control virus diseases. Papayaringspot virus (PRSV), Potyviridae, causes severe economical losses in papaya and cucurbit production worldwide. However,no resistance gene against PRSV has been identified to date. This study aimed to identify candidate PRSV resistance genesusing cDNA-AFLP analysis and offered an open architecture and transcriptomic method to study those transcriptsdifferentially expressed after virus inoculation. The whole genome expression profile of Cucumis metuliferus inoculated withPRSV was generated using cDNA-amplified fragment length polymorphism (cDNA-AFLP) method. Transcript derivedfragments (TDFs) identified from the resistant line PI 292190 may represent genes involved in the mechanism of PRSVresistance. C. metuliferus susceptible Acc. 2459 and resistant PI 292190 lines were inoculated with PRSV and subsequentlytotal RNA was isolated for cDNA-AFLP analysis. More than 400 TDFs were expressed specifically in resistant line PI 292190. Atotal of 116 TDFs were cloned and their expression patterns and putative functions in the PRSV-resistance mechanism werefurther characterized. Subsequently, 28 out of 116 candidates which showed two-fold higher expression levels in resistant PI292190 than those in susceptible Acc. 2459 after virus inoculation were selected from the reverse northern blot andbioinformatic analysis. Furthermore, the time point expression profiles of these candidates by northern blot analysissuggested that they might play roles in resistance against PRSV and could potentially provide valuable information forcontrolling PRSV disease in the future

    Intakes of fruits, vegetables and carbohydrate and the risk of CVD

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    BACKGROUND: Low-carbohydrate diets could lead to reduced fruit and vegetable intake, which may be protective against CVD. The role of carbohydrate intake in modifying the association between fruits and vegetables and CVD has not been evaluated. OBJECTIVE: To evaluate whether carbohydrate intake affects the association between fruits and vegetables and CVD. DESIGN: We included participants from two large prospective studies, the Nurses' Health Study (NHS) and the Health Professionals' Follow-Up Study (HPFS). We followed 70870 eligible NHS females for 16 years and 38918 eligible HPFS males for 14 years. Diet was assessed from an FFQ updated every 4 years. Our primary outcome was ischaemic CVD (fatal and non-fatal myocardial infarction and ischaemic stroke). We used Cox proportional hazards models to evaluate the relationship between fruits and vegetables and ischaemic CVD within groups with low, moderate or high carbohydrate intake. RESULTS: Fruit intake was strongly related with carbohydrate intake, but vegetables showed a very small correlation. Vegetable intake showed stronger associations with ischaemic CVD among the low carbohydrate group (multivariate risk ratio (RR) = 0.82 for an increment of 3 servings/d; 95% CI 0.68, 0.99); green leafy vegetables and carotene-rich fruits and vegetables followed a similar pattern. Total fruit intake was associated with a lower risk of ischaemic CVD only among participants with moderate carbohydrate intake (RR = 0.81 comparing extreme quintiles; 95% CI 0.70, 0.94). CONCLUSIONS: Total vegetables, green leafy vegetables and carotene-rich fruits and vegetables showed stronger associations with ischaemic CVD among the low carbohydrate group. No consistent trends were observed for fruit intake
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