K factor

With the proliferation of wireless devices in recent years, there is a growing need to test the operation and functionality of these various devices in different multipath environments, ranging from line-of-sight environment to a pure Rayleigh environment. In this paper we discuss how a reverberation chamber can be used to simulate a controllable Rician radio environment for the testing of a wireless device. We show that by varying the characteristics of the reverberation chamber and/or the antenna configurations in the chamber, any desired Rician -factor can be obtained. Expressions for the desired -factor as a function of the chamber and antenna characteristics will be presented. Experimental results are presented to illustrate the validity of these expressions, to show how the reverberation chamber can be used to simulate different multipath environments, and to show the realization of a controlled -factor test facility. We present both a one-antenna and a two-antenna test configuration approach.

Whereas the heritability of general intelligence (g) is very well documented, there are relatively few reports of the heritability of life history speed (K). Moreover, the correlation between g and K is of great theoretical significance. Here, we examine the heritabilities of g and K in a sample of 2123 complete Swedish twin pairs, as well as looking for evidence of common genetic variance between the two. We find a significant albeit very small correlation between relatively strong measures of g (the Wiener Matrizen Test) and K (the Mini-K; r = .03, p < .05). Controlling for attenuation by reliabilities and imperfect validity using validity generalization increased the correlation to rho = .05 (p < .05). There was no significant common additivity between g and K, however path elimination in behavior genetic structural equations modeling suggests that the small common variance is nonetheless likely to stem from shared additive genetic influences rather than from environmental influences. The implications of this are discussed. Our new estimate of the heritability of the life history in the Swedish population is a particularly significant result, as the heritability of life history speed has never before been established in non-US samples.

Context: Studies carried out in low voltage networks have explored the modeling of linear single-phase loads (such as motors) and non-linear ones (such as those based on power electronics). However, induction motors exhibit non-linear characteristics between voltage and current due to the saturation of their magnetic parts. Therefore, it is necessary to study induction motors in the frequency domain with a model that allows reviewing the characteristic nonlinearity of their voltage-current interaction. Methodology: This article presents the frequency domain modeling of a single-phase induction motor used as a silent air extractor (127 V, 60 Hz, 66 W), which presents a capacitive behavior (fp = 0,93 in leading) and harmonic distortion due to a third-order component (7,0 %) when fed with a pure sinusoidal voltage of 127 V. Results: This work establishes the parameters of two approaches to the Norton equivalent model (coupled and decoupled admittance matrix) which are used to estimate the distorted current signal and the values of consumed active and non-active power. The results show comparisons errors of P, Q, THDi, and NRMSE indices of less than 7, 4, 14, and 3 %, respectively. Conclusions: The parameters of the Norton equivalent model estimated for the single-phase induction motor allow calculating the current signal with a high degree of precision. This signal exhibits nonlinear characteristics and a capacitive behavior due to the permanent presence of a capacitor aiding the start and operation of the engine.

Context: Studies carried out in low voltage networks have explored the modeling of linear single-phase loads (such as motors) and non-linear ones (such as those based on power electronics). However, induction motors exhibit non-linear characteristics between voltage and current due to the saturation of their magnetic parts. Therefore, it is necessary to study induction motors in the frequency domain with a model that allows reviewing the characteristic nonlinearity of their voltage-current interaction. Methodology: This article presents the frequency domain modeling of a single-phase induction motor used as a silent air extractor (127 V, 60 Hz, 66 W), which presents a capacitive behavior (fp = 0,93 in leading) and harmonic distortion due to a third-order component (7,0%) when fed with a pure sinusoidal voltage of 127 V. Results: This work establishes the parameters of two approaches to the Norton equivalent model (coupled and decoupled admittance matrix) which are used to estimate t...

Among Universal Soil Erosion Equation (USLE) factors (R, K, L, S and P), Soil Erodibility Factor (K) is one of the most important and key factors which determines soil particles resistance to be detachment by water erosion (rainfall and/or runoff) forces. In fact, K factor is the rate of soil loss per rainfall erosion index unit and affected by 6 parameters including soil primary particles (silt, sand and clay), organic matter content and also permeability and structure of soil. The USLE nomograph is one of the most rapid and common methods for calculating K factor based on mentioned parameters. In this study, 38 samples of surface soil (0-15 cm) were collected from Yamchi watershed and the percentage of silt, sand, clay and organic matter content were determined in soil laboratory. Also textures of soil samples were determined to choice soil permeability and structure class codes based on United States Department of Agriculture (USDA) published information. Using USLE nomograph equation, K factor was calculated for each soil sample and based on kriging interpolation method, soil erodibility factor (K) map was constructed for entire study area which average soil erodibility factor and average standard error of interpolated map were 0.442 and 0.0076 t•ha•h•ha −1 •Mj −1 •mm −1 , respectively.

Díaz P., José Gregorio;Arcila, Juan;Steblina, Charles Efectos del uso masivo de bombillos ahorradores de energía sobre los transformadores de distribución Ingeniería UC, Vol. 15, Núm. 1, abril, 2008, pp. 69-76 Universidad de Carabobo Venezuela ... ¿Cómo citar? Número completo ...

Erosion estimates for black soils in Mexico based on the Universal Soil Loss Equation (USLE) present discrepancies due to generalizations that lead to errors in permissible limits, with the erodibility factor or K factor (FK) being the most sensitive. The objective of the present investigation was to obtain a reasonable FK range for a Phaeozem (PH) from central Mexico by contrasting two equations based on the USLE. Samples were randomly obtained at three sites (P1, P2, P3) of a four-hectare area. The percentage of organic matter, textural class, soil structure, and profile permeability were determined. The results reveal differences between the estimated FK (FKe) and reference FK (FKr), whose values were +0.015, +0.028, and +0.029 for P1, P2, and P3, respectively. The differences represent underestimations that are up to 1.7 times greater in magnitude for FKr with respect to FKe. The statistical analysis rejects the null hypothesis (H0) that the means of each site evaluated are the ...

In recent years there has been very extensive use of power electronic devices, which result in harmonic proliferation in the power distribution system. In this paper, as per IEEE C 57.110 standards, procedure to calculate total loss in the distribution transformer under non-linear distortion environment is proposed. The power factor capacitor performance under non-linear load conditions is also analyzed. The relation of total current harmonic distortion in the distribution system with load power factor, transformer losses, efficiency and maximum current delivered is also analyzed. The mitigation methods are proposed to minimize the non-linear load impact on the distribution transformer performance. Instead of K-factor transformer approach, a passive harmonic filter method is developed based on higher savings in energy losses. The simulation studies, are performed using Math works MATLAB 7.0.1 for distribution system at 11/0.440 kV, 200 kVA distribution transformer under non-linear balanced load conditions. It is observed that the power factor capacitor bank acts as a source of harmonic under the nonlinear load conditions in the presence of passive filters.

Given a bicolored point set S, it is not always possible to construct a monochromatic geometric planar k-factor of S. We consider the problem of finding such a k-factor of S by using auxiliary points. Two types are considered: white points whose position is fixed, and Steiner points which have no fixed position. Our approach provides algorithms for constructing those k-factors, and gives bounds on the number of auxiliary points needed to draw a monochromatic geometric planar k-factor of S.

We study the existence of monochromatic planar geometric k-factors on sets of red and blue points. When it is not possible to find a k-factor we make use of auxiliary points: white points, whose position is given as a datum and which color is free; and Steiner points whose position and color is free. We present bounds on the number of white and/or Steiner points necessary and/or sufficient to draw a monochromatic planar geometric k-factor.

Water erodibility of soils can be measured in the field using rainfall simulators or be predicted with mathematical models as USLE and WEPP. The objective of our research was to determine water erodibility of three representative soils in the southern semiarid region of Argentina, aiming to a comparison with the estimated by the WEPP and USLE models. In Bahía Blanca (SBB) and Cabildo (SC) soils-Petrocalcic Paleustolls-and Villarino (SV) soil-Petrocalcic Calciustoll, two consecutive rainfalls of 32 mm during 30 minutes were applied by a rainfall simulator. Soil loss owed to first and second rain indicated: SV 3,26 and 5,86 Mg ha-1 h-1 ; SC 2,04 and 5,53 Mg ha-1 h-1 ; SBB 0,75 and 2,66 Mg ha-1. h-1 Soil resistance to water erosion correlated to silt/clay ratio (r: 0,60); OC (r: 0,55) and structural stability (r: 0,56). Average runoff and sedimentation were: SV 12,4 10-6 m s-1 and 15,6 10-5 kg s-1 m-2 ; SC 9,9 10-6 m s-1 and 13,5 10-5 kg s-1 m-2 ; SBB 9,6 10-6 m s-1 and 6,1 10-5 kg s-1 m-2. Behavior of SV soils is explained by a fast top sealing whilst SBB and SC is related to structural stability. In accord to WEPP the measured interill erodibility (Ki) was SV 2,5; SC 1,89 and SBB 1,39 (10 6 kg s m-4) whereas the estimated value was significantly higher, being SV 6,26; SC 10,2 and SBB 10,2 (10 6 kg s m-4). Erosion indexes (IE) were SV 0,30; SC 0,21 and SBB 0,10 Mg MJ-1 , highly differing from estimated K, which confirms that nomograph predicted values have low confidence in soils with a higher than 65% sand content in texture.

We study the existence of monochromatic planar geometric k-factors on sets of red and blue points. When it is not possible to find a k-factor we make use of auxiliary points: white points, whose position is given as a datum and which color is free; and Steiner points whose position and color is free. We present bounds on the number of white and/or Steiner points necessary and/or sufficient to draw a monochromatic planar geometric k-factor.

We present a measurement of Z 0 boson and Drell-Yan production cross sections in p p collisions at ͱs ϭ1.8 TeV using a sample of 107 pb Ϫ1 accumulated by the Collider Detector at Fermilab. The Drell-Yan cross section is measured in the mass range of M Ͼ40 GeV/c 2. We compare the measurements with the predictions of quantum chromodynamics in both leading order and next-to-leading order, incorporating the recent parton distribution functions. The measurements are consistent with the standard model expectations. ͓S0556-2821͑99͒01603-3͔

A Soil erodibility factor K values (for nomograph) has been obtained for 13 soils that represent the Azul stream upper watershed, which is the main creek of the District. Values obtained have low variation (cv:0,20). In reference to the correlations with the properties valuated, clay (R2 =0,71) is the most adjusted to them, followed by the sand with R2=0,68. Actual data also shows that silt (R2=0,06) as well as residue cover (R2 =0,01), have low correlation with K. Also, very fine sand (R2=0,20 ) and soil organic matter (R2=0,10) are low coefficients. Trends show that soil texture relates with K: they show good response to clay, total sands and organic matter theoretical principles, but they show no response to silt and very fine sand. Bulk density values of first ten centimetres show a positive correlation. Every property valuated has low variation coefficient (between 0,10 and 0,34). Erodibility quantification and its relationship with some soil properties may contribute to unders...

Genetic algorithm (GA) is now an important tool in the field of wireless communications. For multiple-input/multiple-output (MIMO) wireless communications system employing spatial multiplexing transmission, we evaluate the effects of GA parameters value on channel parameters in fading channels. We assume transmit-correlated Rayleigh and Rician fading with realistic Laplacian power azimuth spectrum. Azimuth spread (AS) and Rician K-factor are selected according to the measurement-based WINNER II channel model for several scenarios. Herein we have shown the effects of GA parameters and channel parameters in different WINNER II scenarios (i.e., AS and K values) and rank of the deterministic components. We employ meta GA that suitably selects the population (P), generation (G) and mutation probability (p m) for the inner GA. Then we show the cumulative distribution function (CDF) obtain experimentally for the condition number C of the channel matrix H. It is found that, GA parameters depend on the channel parameters, i.e., GA parameters are the functions of the channel parameters. It is also found that for the poorer channel conditions smaller GA parameter values are required for MIMO detection. This approach will help to achieve maximum performance in practical condition for the lower numerical complexity.

We study the existence of monochromatic planar geometric k-factors on sets of red and blue points. When it is not possible to find a k-factor we make use of auxiliary points: white points, whose position is given as a datum and which color is free; and Steiner points whose position and color is free. We present bounds on the number of white and/or Steiner points necessary and/or sufficient to draw a monochromatic planar geometric k-factor.

En este artículo se presenta una revisión de las metodologías principales empleadas en la obtención de modelos de carga compuestos en sistemas eléctricos de potencia. Como estrategia de presentación de esta investigación, inicialmente se realiza la descripción y clasificación de las metodologías empleadas para obtener los modelos de carga compuestos, de sus diferentes modificaciones y de la utilización de nuevas herramientas durante los últimos años, de acuerdo con la información disponible en más de 60 referencias encontradas en las principales bases de datos. Las ventajas del modelo de carga compuesto se comprueban en la parte final del artículo, en donde se compara su comportamiento con el modelo de carga estático y se hace un análisis de la capacidad de generalización ante diferentes perturbaciones del sistema de potencia.Este trabajo sirve como una referencia útil en la discusión relacionada con aplicaciones del modelado de carga en los sistemas eléctricos de potencia.

Aunque en el mundo no se encuentran llanuras que ocupen grandes extensiones, en Argentina tales ambientes son particularmente relevantes tanto en su expresion areal cuanto a su valor para la produccion agropecuaria. En la denominada Pampa Deprimida (9.7 millones de hectareas) el relieve es sumamente llano, con una pendiente promedio inferior al 0.1%, llegando en sectores proximos a la costa a valores cercanos al 0.001%. Segun Tricart (1973), la debilidad del potencial morfogenetico de la Pampa Deprimida favorece la presencia de suelos muy antiguos, total o parcialmente conservados, alternando con suelos mas recientes y desarrollados dentro de los anteriores. Asi, se conforma un paisaje sin relieve marcado, caracterizado por la presencia de suelos con distintos grados de alcalinidad, salinidad e hidromorfismo, distribuidos en forma de mosaico por toda el area. Estos factores y la cantidad e intensidad de las lluvias son responsables de las frecuentes inundaciones y anegamientos de va...

A Soil erodibility factor K values (for nomograph) has been obtained for 13 soils that represent the Azul stream upper watershed, which is the main creek of the District. Values obtained have low variation (cv:0,20). In reference to the correlations with the properties valuated, clay (R2 =0,71) is the most adjusted to them, followed by the sand with R2=0,68. Actual data also shows that silt (R2=0,06) as well as residue cover (R2 =0,01), have low correlation with K. Also, very fine sand (R2=0,20 ) and soil organic matter (R2=0,10) are low coefficients. Trends show that soil texture relates with K: they show good response to clay, total sands and organic matter theoretical principles, but they show no response to silt and very fine sand. Bulk density values of first ten centimetres show a positive correlation. Every property valuated has low variation coefficient (between 0,10 and 0,34). Erodibility quantification and its relationship with some soil properties may contribute to unders...

We present a measurement of Z 0 boson and Drell-Yan production cross sections in p p collisions at ͱs ϭ1.8 TeV using a sample of 107 pb Ϫ1 accumulated by the Collider Detector at Fermilab. The Drell-Yan cross section is measured in the mass range of M Ͼ40 GeV/c 2. We compare the measurements with the predictions of quantum chromodynamics in both leading order and next-to-leading order, incorporating the recent parton distribution functions. The measurements are consistent with the standard model expectations. ͓S0556-2821͑99͒01603-3͔

Given a bicolored point set S, it is not always possible to construct a monochromatic geometric planar k-factor of S. We consider the problem of finding such a k-factor of S by using auxiliary points. Two types are considered: white points whose position is fixed, and Steiner points which have no fixed position. Our approach provides algorithms for constructing those k-factors, and gives bounds on the number of auxiliary points needed to draw a monochromatic geometric planar k-factor of S.

Although the problem of soil erosion is common in all countries, it is one of the more persisting hazards in developing countries like Ethiopia which is a country located in tropic where there is higher precipitation and is vulnerable to almost all forms of environmental degradation which is also resulted from poor resource conservation practices. The main objective of this study is to determine soil erodibility and susceptibility to soil erosion in Shonkola mountainous area, Soro district. To determine soil erodibility and susceptibility to soil erosion, the percentage of primary soil separates (silt, very fine sand, and clay); percentage of organic matter; soil structure classes; and soil permeability were estimated. Soil samples were collected from 56 locations at an average depth of 15 cm to employ soil texture nomograph. Thus, soil erodibility of Shonkola area is determined and mapped to envisage the area that is highly susceptible for soil erosion. The soil erodibility value r...

  Objetivo: El objetivo de este trabajo es mostrar cómo el uso de un sistema de control de producción que registra y gestiona las operaciones mineras, enfocado en el seguimiento y control de los equipos, procesos y activos, mejora la eficiencia del sistema de información de una empresa, de modo que tenga un soporte adecuado. Metodología: En este trabajo se utiliza el software Pitram versión 1.0, desarrollado por la empresa Micromine, que permite detectar las falencias en el sistema de información del área de producción en una pequeña mina subterránea de oro y plata, ubicada en Argentina. La metodología consistió en cinco pasos fundamentales: a) capacitación, b) recolección de datos, c) ingreso de datos al sistema, c) validación del modelo y d) análisis y resultados. Resultados: Se obtuvo una mayor cantidad y variedad de datos con respecto a la información que registraba  la empresa al momento de realizar el presente trabajo, que fueron propicios para tomar decisiones sobre el contro...

Modelling soil erosion is mostly hampered by low data availability, particularly of soil parameters. One key parameter for soil erosion modelling is the soil erodibility, expressed as the K-factor in the commonly used soil erosion model USLE (Universal Soil Loss Equation). The K-factor is related to crucial soil factors triggering erosion (organic matter content, soil texture, soil structure, permeability). We calculated soil erodibility using measured soil data, collected during the 2009 LUCAS (Land Use and Cover Area frame Survey) soil survey campaign across the member states of the European Union. The soil erodibility dataset overcomes the problems of limited data availability for K-factor assessment and presents a high quality resource for modellers who aim at soil erosion estimation on local/regional, national or European scale.

Given a bicolored point set S, it is not always possible to construct a monochromatic geometric planar k-factor of S. We consider the problem of finding such a k-factor of S by using auxiliary points. Two types are considered: white points whose position is fixed, and Steiner points which have no fixed position. Our approach provides algorithms for constructing those k-factors, and gives bounds on the number of auxiliary points needed to draw a monochromatic geometric planar k-factor of S.

We study the existence of monochromatic planar geometric k-factors on sets of red and blue points. When it is not possible to find a k-factor we make use of auxiliary points: white points, whose position is given as a datum and which color is free; and Steiner points whose position and color is free. We present bounds on the number of white and/or Steiner points necessary and/or sufficient to draw a monochromatic planar geometric k-factor.

Soil erodibility is among the trickiest erosion factors to estimate. This is especially true for heterogeneous Mediterranean environments, where reliable and dense soil data are rarely available, and interpolation methods give very low accuracies. Towards estimating soil erodibility, research so far has resulted in several alternatives mainly based on empirical formulas, on physics-based equations or on inference with expertise. The aim of this work was to compare erodibility patterns derived by using the empirical United States Department of Agriculture (USDA) formula and by inference from a geological map in a Mediterranean agricultural site. The Kolymvari area, located in the western part of Crete, an area covered by olive groves and citrus orchards, was selected as the study site for this work. Comparison of the spatial patterns of soil erodibility derived from the two alternatives showed significant differences (i.e., a mean normalized difference value of 0.52), while a test of the "inference" alternative indicated very low accuracies (0.1475 RMS error). A comparison, however, of the spatial patterns of erosion values derived from both alternatives indicated that dissimilarities of the two soil erodibility maps faded out. Moreover, the highly risky areas provided by both alternatives were found to be identical for 88% of the whole study site.

Life history (LH) theory provides an evolutionary theoretical framework for understanding individual differences in maturation, mating, reproduction, parenting, and social interaction. However, the psychometric assessment of human life history has been largely limited to generalized self-reports. Using template matching, this article examines the relationship between personality differences associated with slow-life history (slow-LH) and social behavior in 3 archival datasets. Two of these datasets include direct observations of behavior in the laboratory, and the 3rd provides self-reports of behavior in real life situations experienced within the preceding 24 hr. The results paint a consistent picture of the slow-LH individual as engaging in numerous adaptive social behaviors. However, when "normativeness" (the tendency for most people to be normal in both the statistical and evaluative sense) is statistically removed from the LH scores, a slightly different picture emerges. Both slow-LH and fast-LH persons display a number of behaviors that may be either adaptive or maladaptive in different contexts. Specifically, slow-LH individuals tended to behave in a manner that was considerate, kind, hard-working, and reliable but also socially awkward, insecure, and overcontrolling. Fast-LH individuals came across as talkative, socially skilled, dominant, and charming but also unpredictable, hostile, manipulative, and impulsive. These results are consistent with the evolutionary interpretation of LH strategies as being adapted to systematically different environments rather than better or worse approaches to reproductive fitness overall.

A well-known formula of Tutte and Berge expresses the size of a maximum matching in a graph G in terms of what is usually called the deficiency. A subset X of V (G) for which this deficiency is attained is called a Tutte set of G. While much is known about maximum matchings, less is known about the structure of Tutte sets. We explored the structural aspects of Tutte sets in another paper. Here, we consider the algorithmic complexity of finding Tutte sets in a graph. We first give two polynomial algorithms for finding a maximal Tutte set. We then consider the complexity of finding a maximum Tutte set, and show it is NP-hard for general graphs, as well as for several interesting restricted classes such as planar graphs. By contrast, we show we can find maximum Tutte sets in polynomial time for graphs of level 0 or 1, elementary graphs, and 1-tough graphs.

Resumen Contexto: Debido a la dificultad para realizar la prueba de aptitud al cortocircuito en transformadores de gran potencia, la norma IEC 60076-5 2006 de la Comisión Electrotécnica Internacional acepta como método alternativo la estimación de las fuerzas y esfuerzos a través de cálculo y consideraciones de diseño. Método: En este artículo se presenta la implementación del método analítico de Roth para el cálculo de las fuerzas axiales y radiales de cortocircuito en un transformador trifásico con núcleo tipo columnas de 630kVA. Resultados: Las fuerzas máximas obtenidas con el método de Roth son comparables con las calculadas a través de métodos modernos para el diseño de transformadores como el método de elementos finitos, las diferencias entre los cálculos fueron mínimas a excepción de la fuerza axial máxima del devanado de baja tensión. Conclusiones: Aunque el método de Roth es una herramienta tradicional para solución de problemas de electromagnetismo, este es adecuado para hacer una estimación rápida y sencilla de parámetros magnéticos y fuerzas de cortocircuito en transformadores.

Erosion estimates for black soils in Mexico based on the Universal Soil Loss Equation (USLE) present discrepancies due to generalizations that lead to errors in permissible limits, with the erodibility factor or K factor (FK) being the most sensitive. The objective of the present investigation was to obtain a reasonable FK range for a Phaeozem (PH) from central Mexico by contrasting two equations based on the USLE. Samples were randomly obtained at three sites (P1, P2, P3) of a four-hectare area. The percentage of organic matter, textural class, soil structure, and profile permeability were determined. The results reveal differences between the estimated FK (FKe) and reference FK (FKr), whose values were +0.015, +0.028, and +0.029 for P1, P2, and P3, respectively. The differences represent underestimations that are up to 1.7 times greater in magnitude for FKr with respect to FKe. The statistical analysis rejects the null hypothesis (H0) that the means of each site evaluated are the ...

The Erd\H{o}s--Gallai Theorem states that for $k \geq 3$, any $n$-vertex graph with no cycle of length at least $k$ has at most $\frac{1}{2}(k-1)(n-1)$ edges. A stronger version of the Erd\H{o}s--Gallai Theorem was given by Kopylov: If $G$ is a 2-connected $n$-vertex graph with no cycle of length at least $k$, then $e(G) \leq \max\{h(n,k,2),h(n,k,\lfloor \frac{k-1}{2}\rfloor)\}$, where $h(n,k,a) := {k - a \choose 2} + a(n - k + a)$. Furthermore, Kopylov presented the two possible extremal graphs, one with $h(n,k,2)$ edges and one with $h(n,k,\lfloor \frac{k-1}{2}\rfloor)$ edges. In this paper, we complete a stability theorem which strengthens Kopylov&#39;s result. In particular, we show that for $k \geq 3$ odd and all $n \geq k$, every $n$-vertex $2$-connected graph $G$ with no cycle of length at least $k$ is a subgraph of one of the two extremal graphs or $e(G) \leq \max\{h(n,k,3),h(n,k,\frac{k-3}{2})\}$. The upper bound for $e(G)$ here is tight.

En este artículo se presenta una revisión de las metodologías principales empleadas en la obtención de modelos de carga compuestos en sistemas eléctricos de potencia. Como estrategia de presentación de esta investigación, inicialmente se realiza la descripción y clasificación de las metodologías empleadas para obtener los modelos de carga compuestos, de sus diferentes modificaciones y de la utilización de nuevas herramientas durante los últimos años, de acuerdo con la información disponible en más de 60 referencias encontradas en las principales bases de datos. Las ventajas del modelo de carga compuesto se comprueban en la parte final del artículo, en donde se compara su comportamiento con el modelo de carga estático y se hace un análisis de la capacidad de generalización ante diferentes perturbaciones del sistema de potencia.Este trabajo sirve como una referencia útil en la discusión relacionada con aplicaciones del modelado de carga en los sistemas eléctricos de potencia.

In this article we have derived the minimum order of an odd regular graph such that the graph has no matching. We have observed that how it is different from the case of even regular graphs. We have checked the consistency of the derived result with Petersen&#39;s theorem.

Copyright © 2015 Ilya V. Osipov et al. This article is distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The paper describes user behavior as a result of introducing monetization in the freemium educational online platform. Monetization resulted in alternative system growth mechanisms causing viral increase in the number of users. System metrics in terms of the K-factor was utilized as an indicator of the system user base growth. The weekly K-factor doubled as a result of monetization introduction.

Aunque en el mundo no se encuentran llanuras que ocupen grandes extensiones, en Argentina tales ambientes son particularmente relevantes tanto en su expresion areal cuanto a su valor para la produccion agropecuaria. En la denominada Pampa Deprimida (9.7 millones de hectareas) el relieve es sumamente llano, con una pendiente promedio inferior al 0.1%, llegando en sectores proximos a la costa a valores cercanos al 0.001%. Segun Tricart (1973), la debilidad del potencial morfogenetico de la Pampa Deprimida favorece la presencia de suelos muy antiguos, total o parcialmente conservados, alternando con suelos mas recientes y desarrollados dentro de los anteriores. Asi, se conforma un paisaje sin relieve marcado, caracterizado por la presencia de suelos con distintos grados de alcalinidad, salinidad e hidromorfismo, distribuidos en forma de mosaico por toda el area. Estos factores y la cantidad e intensidad de las lluvias son responsables de las frecuentes inundaciones y anegamientos de va...

This paper presents the analysed results from a dynamic spatial-temporal measurement campaign conducted at 5.2 GHz in a corridor environment within a modern building. The Single-Input-Multiple-Output (SIMO) measurement was performed by moving the transmitting antenna with a specialised trolley along a predefined route, while the receiving linear array was fixed at one location. Subsequent post-processing was conducted using the 2-D Unitary ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) super-resolution algorithm to extract the direction-of-arrival (DoA) and time-delay-of-arrival (TDoA) of the multipath components. The corridor was then characterised in terms of delay spread, azimuth spread, K-factor and coherence bandwidth. It was found that the corridor favours a wave-guiding effect whereas locations adjacent to the corridor enjoy the leakage of energy from the waves propagating along the corridor. The dynamic power delay spectrums are shown. Finally, the correlations between the delay spread, azimuth spread and coherence bandwidth are assessed.

Aunque en el mundo no se encuentran llanuras que ocupen grandes extensiones, en Argentina tales ambientes son particularmente relevantes tanto en su expresion areal cuanto a su valor para la produccion agropecuaria. En la denominada Pampa Deprimida (9.7 millones de hectareas) el relieve es sumamente llano, con una pendiente promedio inferior al 0.1%, llegando en sectores proximos a la costa a valores cercanos al 0.001%. Segun Tricart (1973), la debilidad del potencial morfogenetico de la Pampa Deprimida favorece la presencia de suelos muy antiguos, total o parcialmente conservados, alternando con suelos mas recientes y desarrollados dentro de los anteriores. Asi, se conforma un paisaje sin relieve marcado, caracterizado por la presencia de suelos con distintos grados de alcalinidad, salinidad e hidromorfismo, distribuidos en forma de mosaico por toda el area. Estos factores y la cantidad e intensidad de las lluvias son responsables de las frecuentes inundaciones y anegamientos de va...

Soil surface random roughness strongly infuences its hydrologic response. The aim of this work was to quantify the dynamics of the surface roughness for a Vertic Argiudoll which was subjected to natural rainfall and was kept in a rough, bare or covered surface condition. For that purpose, 0,25 m2 square microplots containing 20 kg of a topsoil devoted to 8 years of conventional agriculture were prepared. Plant residues were hand removed but soil clods were kept undisturbed. The period of measurements included a four months summer fallow, in which rainfall and surface roughness were periodically monitored. The relative roughness (roughness measured after rainfalls / initial roughness measured immediately after tillage) from the covered treatment was significantly higher than that of the uncovered treatment. This confirmed the influence of rainfall kinetic energy on the obtained results because cumulative rainfall was the same for both treatments. This influence was explained with the...

Contexto: El reciente incremento de accidentes, percances o siniestros viales en los sistemas urbanos con características metropolitanas ha originado preocupación en las autoridades encargadas de planificar la movilidad y los subsistemas de transporte. Efectivamente, se tiene convergencia que la ocurrencia de este tipo de eventos se aleja de factores puramente estocásticos, que son resultado de anomalías asociadas con la interacción intrasistémica del vehículo, el usuario y el camino. En este sentido, el objetivo de este trabajo consiste en determinar por medio del análisis sistémico los componentes que están provocando entropía en la segunda metrópoli más importante de México. Método: En este análisis se utilizan los preceptos de la teoría de los sistemas; de tal forma que a través de la triangulación de datos obtenidos in situ y solventados documentalmente se determinan los componentes causales de entropía intrasistémica. Para ello, se elabora una derivación modificada del modelo ...

Soil erodibility is among the trickiest erosion factors to estimate. This is especially true for heterogeneous Mediterranean environments, where reliable and dense soil data are rarely available, and interpolation methods give very low accuracies. Towards estimating soil erodibility, research so far has resulted in several alternatives mainly based on empirical formulas, on physics-based equations or on inference with expertise. The aim of this work was to compare erodibility patterns derived by using the empirical United States Department of Agriculture (USDA) formula and by inference from a geological map in a Mediterranean agricultural site. The Kolymvari area, located in the western part of Crete, an area covered by olive groves and citrus orchards, was selected as the study site for this work. Comparison of the spatial patterns of soil erodibility derived from the two alternatives showed significant differences (i.e., a mean normalized difference value of 0.52), while a test of the "inference" alternative indicated very low accuracies (0.1475 RMS error). A comparison, however, of the spatial patterns of erosion values derived from both alternatives indicated that dissimilarities of the two soil erodibility maps faded out. Moreover, the highly risky areas provided by both alternatives were found to be identical for 88% of the whole study site.

Modelling soil erosion is mostly hampered by low data availability, particularly of soil parameters. One key parameter for soil erosion modelling is the soil erodibility, expressed as the K-factor in the commonly used soil erosion model USLE (Universal Soil Loss Equation). The K-factor is related to crucial soil factors triggering erosion (organic matter content, soil texture, soil structure, permeability). We calculated soil erodibility using measured soil data, collected during the 2009 LUCAS (Land Use and Cover Area frame Survey) soil survey campaign across the member states of the European Union. The soil erodibility dataset overcomes the problems of limited data availability for K-factor assessment and presents a high quality resource for modellers who aim at soil erosion estimation on local/regional, national or European scale.

We study the existence of monochromatic planar geometric k-factors on sets of red and blue points. When it is not possible to find a k-factor we make use of auxiliary points: white points, whose position is given as a datum and which color is free; and Steiner points whose position and color is free. We present bounds on the number of white and/or Steiner points necessary and/or sufficient to draw a monochromatic planar geometric k-factor.

Аннотация. В настоящее время все больше продуктов, как то мобильные приложения, SaaS-решения, software, web-приложения переходят на экономическую модель фримиум. Эта модель имеет множество особенностей. В статье исследована статистика поведения пользователей на примере образовательной коллаборационной платформы, рассматриваются взаимосвязи между ключевыми параметрами этой модели: показателями виральности, ретеншна, монетизации, а также особенностями их расчета. Предложен новый целевой параметр F-Growth, позволяющий в сумме оценить «зрелость» интернет-проекта модели фримиум, с целью получения внешних инвестиций и вывода на международный рынок.

We study the temporal fluctuations of a fixed wireless link in an urban environment by characterizing the Ricean K-factor as a function of the positioning of the customer premises antenna. Our main observation is that temporal fluctuation of received power is due mainly to vehicular traffic close to the remote antenna. Furthermore, a strong correlation between average envelope power and K-factor is observed when placing the remote antenna at similar distances to traffic. Therefore, optimizing antenna placement based on received power reduces fade depth at the same time.