Multivariate adaptive regression splines for estimating riverine constituent concentrations

Regression-based methods are commonly used for riverine constituent concentration/flux estimation, which is essential for guiding water quality protection practices and environmental decision making. This paper developed a multivariate adaptive regression splines model for estimating riverine constituent concentrations (MARS-EC). The process, interpretability and flexibility of the MARS-EC modelling approach, was demonstrated for total nitrogen in the Patuxent River, a major river input to Chesapeake Bay. Model accuracy and uncertainty of the MARS-EC approach was further analysed using nitrate plus nitrite datasets from eight tributary rivers to Chesapeake Bay. Results showed that the MARS-EC approach integrated the advantages of both parametric and nonparametric regression methods, and model accuracy was demonstrated to be superior to the traditionally used ESTIMATOR model. MARS-EC is flexible and allows consideration of auxiliary variables; the variables and interactions can be selected automatically. MARS-EC does not constrain concentration-predictor curves to be constant but rather is able to identify shifts in these curves from mathematical expressions and visual graphics. The MARS-EC approach provides an effective and complementary tool along with existing approaches for estimating riverine constituent concentrations

Fermi gas in harmonic oscillator potentials

Assuming the validity of grand canonical statistics, we study the properties of a spin-polarized Fermi gas in harmonic traps. Universal forms of Fermi temperature $T_F$, internal energy $U$ and the specific heat per particle of the trapped Fermi gas are calculated as a {\it function} of particle number, and the results compared with those of infinite number particles.Comment: 8 pages, 1 figure, LATE

Hertz-level Measurement of the 40Ca+ 4s 2S1/2-3d 2D5/2 Clock Transition Frequency With Respect to the SI Second through GPS

We report a frequency measurement of the clock transition of a single ^40Ca^+ ion trapped and laser cooled in a miniature ring Paul trap with 10^-15 level uncertainty. In the measurement, we used an optical frequency comb referenced to a Hydrogen maser, which was calibrated to the SI second through the Global Positioning System (GPS). Two rounds of measurements were taken in May and June 2011, respectively. The frequency was measured to be 411 042 129 776 393.0(1.6) Hz with a fractional uncertainty of 3.9{\times}10^-15 in a total averaging time of > 2{\times}10^6 s within 32 days

Cutting the last wires for mobile communications by microwave power transfer

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Analysis of the influence to productivity of software corrective maintenance using an economic model

© 2014 IEEE. This paper presents an economic model for productivity of software corrective maintenance. The productivity is modeled using economic value of the maintenance process as the output, and the pre-committed fixed cost and variable cost as input. The relationship of the economic value and these cost components are modeled using analytical theory of investment. The values of corrective maintenance process are analyzed. A simulation approach is demonstrated to analyze the influences to the productivity in corrective maintenance. This approach provides a tool to identify and analyze the optimal parameters in productivity using the economic model and simulation

Calibration and Precise Detection of the Irregular Drift of the Tidal Zero Point for a short/medium term Tide Station

The tide gauge is one of the most important auxiliary sensors in hydrographic surveying. Medium and short-term tide stations are established using pressure-type tide gauges to achieve the water level control for the depth measurement along the coast. Affected by the complex marine environment, one of the main factors in determining the accuracy of the water depth measurement is the irregular drift of the tidal zero point, which is usually deter-mined during the engineering practice. However, the relevant theoretical research on detection and correction lags. In this paper, the occurence of irregular drift about tidal zero is analyzed, and a mathematical model for precise processing of drift detection and correc-tion is proposed. Based on the processing of nearly one month of simultaneous tide data at the long-term Dinghai station, the temporary station at Gangxin, as well as the long-term Dafeng station and temporary Sanyazi station, the effect of two daily average sea surface calculation methods on different constituents are analyzed. The results show that the new proposed model is suitable for the precise processing of irregular drift of tide zero point. After the tide zero point correction, the accuracy of the water level observation data of the short-term Gangxin and Sanyazi tide stations is improved from decimetre (dm) to centime-tre (cm) levels.El mareógrafo es uno de los sensores auxiliares más importantes en los levantamientos hidrográficos. Las estaciones de mareas de medio y corto plazo se establecen utilizando mareógrafos de presión afín de lograr el nivel del mar para el control de la medición de profundidad a lo largo de la costa. Afectado por el complejo entorno marino, uno de los principales factores en la determinación de la precisión en la medición de la profundidad del mar es la deriva irregular del punto cero de la marea, que generalmente está basado en la práctica de la ingeniería. Sin embargo, la investigación teórica pertinente sobre la detección y la corrección toma su tiempo. En este artículo, se analiza la ocurrencia de deriva irregular sobre el punto cero de la marea, y se propone un modelo matemático para el procesado preciso de la detección y corrección de la deriva. Basándose en el proceso de casi un mes de datos de mareas obtenidos simultáneamente en la estación Dinghai de largo plazo, en la estación temporal de Gangxin, y también en la estación Dafeng de largo plazo y la estación temporal de Sanyazi, se ha analizado el efecto de dos métodos diarios de cálculo de la superficie media del mar en diferentes componentes. Los resultados muestran que el nuevo modelo propuesto es adecuado para el proceso preciso de la deriva irregular del punto cero de la marea. Después de la corrección del punto cero de la marea, se ha mejorado la precisión de los datos de observación del nivel del mar de las estaciones de marea de corto plazo de Gangxin y Sanyazi, de niveles de decímetros (dm) a centímetros (cm).Le marégraphe est l’un des capteurs auxiliaires les plus importants en matière de levés hydrographiques. Les observatoires de marée de courte/moyenne durée sont établis à l’aide de marégraphes à pression servant à observer le niveau de la mer en vue de mesurer les profondeurs le long de la côte. Affecté par l’environnement maritime complexe, l’un des principaux facteurs permettant de déterminer la précision de la mesure de la profondeur d’eau est la dérive irrégulière du zéro hydrographique, qui repose habituelle-ment sur les pratiques d’ingénierie. Toutefois, la recherche théorique appropriée en matière de détection et de correction a pris du retard. Dans l’article qui suit, l’occurrence de la érive irrégulière du zéro hydrographique est analysée et un modèle mathématique pour le traitement précis de la détection et de la correction de la dérive est proposé. A partir de presqu’un mois de données de marées simultanées recueillies à l’observatoire Dinghai de longue durée, à l’observatoire temporaire de Gangxin, ainsi qu’à l’observatoire Dafeng de longue durée et à l’observatoire temporaire de Sanyazi, les effets de deux méthodes de calcul quotidiennes du niveau moyen de la mer sur différentes composantes harmoniques sont analysés. Les résultats montrent que le nouveau modèle proposé convient pour le traitement précis de la dérive irrégulière du zéro hydrographique. Après la correction du zéro hydrographique, la précision des données sur l’observation du niveau de la mer des stations de courte durée de Gangxin et de Sanyazi est améliorée et passe de l’ordre du décimètre (dm) au centimètre (cm)

Scheme for sharing classical information via tripartite entangled states

We investigate schemes for quantum secret sharing and quantum dense coding via tripartite entangled states. We present a scheme for sharing classical information via entanglement swapping using two tripartite entangled GHZ states. In order to throw light upon the security affairs of the quantum dense coding protocol, we also suggest a secure quantum dense coding scheme via W state in analogy with the theory of sharing information among involved users.Comment: 4 pages, no figure. A complete rewrritten vession, accepted for publication in Chinese Physic