114 research outputs found
Images of Multilinear Polynomials on Generalized Quaternion Algebras
The main goal of this paper is to extend [J. Algebra Appl. 20 (2021),
2150074] to generalized quaternion algebras, even when these algebras are not
necessarily division rings. More precisely, in such cases, the image of a
multilinear polynomial evaluated on a quaternion algebra is a vector space and
we additionally provide a classification of possible images.Comment: One new section is added, namely Section 3, and thus the paper is now
18 page
Flexible Pavement Life Cycle Cost Analysis by Using Monte-Carlo Method and the Suggestions for Developing Countries
Flexible road pavement plays an essential role in developing an effective, economic, and safe operation road network of any country. In Vietnam, a developing country, the selection of a suitable flexible pavement structure is always a challenge due to fiscal limitations. The traditional determinant method (TDM) by which pavement structures are selected mainly on the basis of initial construction costs and traffic load has been used for many years in the nation. This paper presents the use of Monte Carlo simulation to analyze the entire flexible pavement life cycle cost. Data including initial and maintenance costs and road user costs were collected from several different types of existing flexible pavement in Nghe An province, Vietnam. Random variations of several main inputs were explored in order to develop density distribution functions. These functions then were used as the bases for Monte Carlo simulation. One million simulation runs were implemented and the Net Present Values (NPVs) among pavement types were compared under the light of risk analysis. Research results showed that TDM method provided bias and uncertain results compared to that of Monte Carlo one. In terms of long- term pavement performance, a low-cost pavement structure should not always be considered as a wise selection. Some other suggestions for a developing country as Vietnam were also included
Fuzzy gain scheduling control apply to an RC Hovercraft
The Fuzzy Gain Scheduling (FGS) methodology for tuning the Proportional – Integral – Derivative (PID) traditional controller parameters by scheduling controlled gains in different phases, is a simple and effective application both in industries and real-time complex models while assuring the high achievements over pass decades, is proposed in this article. The Fuzzy logic rules of the triangular membership functions are exploited on-line to verify the Gain Scheduling of the Proportional – Integral – Derivative controller gains in different stages because it can minimize the tracking control error and utilize the Integral of Time Absolute Error (ITAE) minima criterion of the controller design process. For that reason, the controller design could tune the system model in the whole operation time to display the efficiency in tracking error. It is then implemented in a novel Remote Controlled (RC) Hovercraft motion models to demonstrate better control performance in comparison with the PID conventional controller
Improving the Performance of Concatenated Convolutional Codes in the Error Floor Region
The idea of the Bit-Interleaved Coded Modulation with Iterative Decoding (BICM-ID) is applied to classic schemes of both parallel and serial concatenation of convolutional codes (PCCC and SCCC) with Binary Phase Shift Keying (BPSK) modulation. Simulation results show that slightly modified PCCC and SCCC schemes provide significant improved performance of the encoder in the error floor region in terms of much lower bit error rate (BER)
NetFPGA Based OpenFlow Switch Extension for Energy Saving in Data Centers
The increasing demand for data centers in both scale and size has led to huge energy consumption. The cost and environmental impact of data centers increases due to large amounts of carbon emissions. One solution to this problem is to intelligently control the power consumption of switches used in data centers. This paper proposes an extension to OpenFlow switches to support different power saving modes. The extension includes defining new messages in the OpenFlow protocol stack and designing an OpenFlow Switch Controller (OSC) that is able to turn on/off switches and disable/enable ports. To prove the soundness of the proposed extension, the functions of an OSC has been integrated in a NetFPGA based OpenFlow switch used in the ECODANE framework. The results presented in this paper can also be used by the OpenFlow compliant switches manufacturer or by power aware research community
Functional Complementation Studies and Analysis of Downstream Regulatory Gene Expression Networks of Trichome Trimeric Complex
In Arabidopsis, previous genetic analysis has revealed that trichome initiation is positively mediated by a trimeric activation complex comprised of an R2R3-MYB protein GLABRA1 (GL1), a basic helix-loop-helix (bHLH) GLABRA3 (GL3) which acts redundantly with its close homolog ENHANCER OF GLABRA3 (EGL3), and a WD40 protein TRANSPARENT TESTA GLABRA1 (TTG1). We studied the functionality of four individual cotton genes MYB2, TTG3, DEL65 and DEL61 from diploid cotton A and D genomes, which show high similarity in sequence with GL1, TTG1, GL3 and EGL3, respectively, in their respective Arabidopsis glabrous mutants. Our complementation assays proved that transgenic lines with MYB2, TTG3 from diploid genomes A and D could rescue the trichomeless phenotype of gl1-1 and ttg1-1, respectively. However, DEL61 from both the species could not rescue this phenotype of gl3-1 egl3-77439 double mutant. Interestingly, the DEL65 from A species rescued gl3-1 egl3-77439 double mutant but not from D diploid species. Comparative quantitative PCR analysis of the downstream regulatory network genes showed a similar pattern for MYB, TTG3 complemented lines from A- and D- diploid species.
Comparative analysis of the DEL65 from A- (rescued the trichomeless phenotype) and D- (did not rescued the trichomeless phenotype) showed differential expression of regulatory network genes between these two lines. These results suggested that MYB2, TTG3 and DEL65, when expressed in Arabidopsis, regulated the regulatory network genes during the trichome initiation process
Spatiotemporal analysis of historical records (2001-2012) on dengue fever in Vietnam and development of a statistical model for forecasting risk
Background: Dengue fever is the most widespread infectious disease of humans transmitted by Aedes mosquitoes. It is the leading cause of hospitalization and death in children in the Southeast Asia and western Pacific regions. We analyzed surveillance records from health centers in Vietnam collected between 2001–2012 to determine seasonal trends, develop risk maps and an incidence forecasting model.
Methods: The data were analyzed using a hierarchical spatial Bayesian model that approximates its posterior parameter distributions using the integrated Laplace approximation algorithm (INLA). Meteorological, altitude and land cover (LC) data were used as predictors. The data were grouped by province (n = 63) and month (n = 144) and divided into training (2001–2009) and validation (2010–2012) sets. Thirteen meteorological variables, 7 land cover data and altitude were considered as predictors. Only significant predictors were kept in the final multivariable model. Eleven dummy variables representing month were also fitted to account for seasonal effects. Spatial and temporal effects were accounted for using Besag-York-Mollie (BYM) and autoregressive (1) models. Their levels of significance were analyzed using deviance information criterion (DIC). The model was validated based on the Theil’s coefficient which compared predicted and observed incidence estimated using the validation data. Dengue incidence predictions for 2010–2012 were also used to generate risk maps.
Results: The mean monthly dengue incidence during the period was 6.94 cases (SD 14.49) per 100,000 people. Analyses on the temporal trends of the disease showed regular seasonal epidemics that were interrupted every 3 years (specifically in July 2004, July 2007 and September 2010) by major fluctuations in incidence. Monthly mean minimum temperature, rainfall, area under urban settlement/build-up areas and altitude were significant in the final model. Minimum temperature and rainfall had non-linear effects and lagging them by two months provided a better fitting model compared to using unlagged variables. Forecasts for the validation period closely mirrored the observed data and accurately captured the troughs and peaks of dengue incidence trajectories. A favorable Theil’s coefficient of inequality of 0.22 was generated.
Conclusions: The study identified temperature, rainfall, altitude and area under urban settlement as being significant predictors of dengue incidence. The statistical model fitted the data well based on Theil’s coefficient of inequality, and risk maps generated from its predictions identified most of the high-risk provinces throughout the country
Essential Facts on the History of Hyperthermia and their Connections with Electromedicine
The term hyperthermia is a combination of two Greek words: HYPER (rise) and
THERME (heat) and refers to the increasing of body temperature or selected
tissues in order to achieve a precise therapeutic effect. This paper reviews
the development of thermotherapy by describing the most important moments in
its history. For decades, the development of hyperthermia ran parallel with the
development of cancer treatment and had numerous connections with
electromedicine. Throughout its history, hyperthermia evoked a number of hopes,
brought spectacular successes, but also was the subject of many
disappointments
Estimating the welfare loss to households from natural disasters in developing countries: a contingent valuation study of flooding in Vietnam
Background: Natural disasters have severe impacts on the health and well-being of affected households. However, we find evidence that official damage cost assessments for floods and other natural disasters in Vietnam, where households have little or no insurance, clearly underestimate the total economic damage costs of these events as they do not include the welfare loss from mortality, morbidity and reduced well-being experienced by the households affected by the floods. This should send a message to the local communities and national authorities that higher investments in flood alleviation, reduction and adaptive measures can be justified since the social benefits of these measures in terms of avoided damage costs are higher than previously thought. Methods: We pioneer the use of the contingent valuation (CV) approach of willingness-to-contribute (WTC) labour to a flood prevention program, as a measure of the welfare loss experienced by household due to a flooding event. In a face-to-face household survey of 706 households in the Quang Nam province in Central Vietnam, we applied this approach together with reported direct physical damage in order to shed light of the welfare loss experienced by the households. We asked about households’ WTC labour and multiplied their WTC person-days of labour by an estimate for their opportunity cost of time in order to estimate the welfare loss to households from the 2007 floods. Results: The results showed that this contingent valuation (CV) approach of asking about willingness-to-pay in-kind avoided the main problems associated with applying CV in developing countries. Conclusion: Thus, the CV approach of WTC labour instead of money is promising in terms of capturing the total welfare loss of natural disasters to households, and promising in terms of further application in other developing countries and for other types of natural disasters
Synthesis and biological evaluation of shikimic acid derivatives
From shikimic acid, new series of oseltamivir analogues containing either ether sulfur or ether oxygen at C-3 position were prepared and evaluated for their biological activities. This is the first report on synthesis of oseltamivir analogues with ether sulfur at C-3. Except for compounds 4d, 4f, 7c and 7d, the remaining compounds were found to be active against MCF-7, LU-1 and KB cell lines. As oseltamivir had no cytotoxicity against different cell lines such as MCF-7, LU-1, KB, MDCK, MRC-5, VERO, MK and 293, the modification of alkyl groups at C-3 of the oseltamivir ring framework could significantly increase the cytotoxicity for this class of compounds. Loss of neuraminidase inhibition activity of these synthetic oseltamivir analogues suggested that the alkyl ether groups at C-3 should be critical for their anti-neuraminidase activity
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