scholarly journals Superresolution Polarimetric ISAR Imaging Based on 2D CP-GTD Model

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Da-hai Dai ◽  
Jing-ke Zhang ◽  
Xue-song Wang ◽  
Shun-ping Xiao
Keyword(s):  
Real Data ◽  
Scattering Matrix ◽  
Geometrical Theory ◽  
Scattering Mechanism ◽  
New Approach ◽  
Scattering Centers ◽  
Isar Imaging ◽  
Geometrical Theory Of Diffraction ◽  
The One ◽  
Better Than

This paper presented a new approach to superresolution ISAR imaging based on a scattering model called coherent polarized geometrical theory of diffraction (CP-GTD) which is better matched to the physical scattering mechanism. The algorithm is a joint processing between polarization and superresolution essentially. It can also estimate the number, position, frequency dependence, span, and normalized scattering matrix of scattering centers instantaneously for each channel rather than the one which extracts parameters from each channel separately, and its performance is better than the latter because the fully polarized information is used. The superiority of the CP-GTD is verified by experiment results based on simulated and real data.

scholarly journals Smart Recommendations for Renting Bikes in Bike-Sharing Systems

2021 ◽  
Vol 11 (20) ◽  
pp. 9654
Author(s):  
Holger Billhardt ◽  
Alberto Fernández ◽  
Sascha Ossowski
Keyword(s):  
Queuing Theory ◽  
Real Data ◽  
Transport Systems ◽  
Bike Sharing ◽  
Usage Patterns ◽  
One Step ◽  
The One ◽  
The Individual ◽  
Recommendation Strategy ◽  
Better Than

Vehicle-sharing systems—such as bike-, car-, or motorcycle-sharing systems—have become increasingly popular in big cities in recent years. On the one hand, they provide a cheaper and environmentally friendlier means of transportation than private cars, and on the other hand, they satisfy the individual mobility demands of citizens better than traditional public transport systems. One of their advantages in this regard is their availability, e.g., the possibility of taking (or leaving) a vehicle almost anywhere in a city. This availability obviously depends on different strategic and operational management decisions and policies, such as the dimension of the fleet or the (re)distribution of vehicles. Agglutination problems—where, due to usage patterns, available vehicles are concentrated in certain areas, whereas no vehicles are available in others—are quite common in such systems, and need to be dealt with. Research has been dedicated to this problem, specifying different techniques to reduce imbalanced situations. In this paper, we present and compare strategies for recommending stations to users who wish to rent or return bikes in station-based bike-sharing systems. Our first contribution is a novel recommendation strategy based on queuing theory that recommends stations based on their utility to the user in terms of lower distance and higher probability of finding a bike or slot. Then, we go one step further, defining a strategy that recommends stations by combining the utility of a particular user with the utility of the global system, measured in terms of the improvement in the distribution of bikes and slots with respect to the expected future demand, with the aim of implicitly avoiding or alleviating balancing problems. We present several experiments to evaluate our proposal with real data from the bike sharing system BiciMAD in Madrid.

A new geometrical method for portfolio optimization

2021 ◽  
Vol 8 (3) ◽  
pp. 400-409
Author(s):  
F. Butin ◽  
Keyword(s):  
Portfolio Optimization ◽  
Euclidean Distance ◽  
Convex Combination ◽  
Short Selling ◽  
Minimal Risk ◽  
Geometrical Method ◽  
New Approach ◽  
Optimization Framework ◽  
The One ◽  
Better Than

Risk aversion plays a significant and central role in investors’ decisions in the process of developing a portfolio. In this portfolio optimization framework, we determine the portfolio that possesses the minimal risk by using a new geometrical method. For this purpose, we elaborate an algorithm that enables us to compute any Euclidean distance to a standard simplex. With this new approach, we can treat the case of portfolio optimization without short-selling in its entirety, and we also recover in geometrical terms the well-known results on portfolio optimization with allowed short-selling. Then, we apply our results to determine which convex combination of the CAC 40 stocks possesses the lowest risk. Thus, we not only obtain a very low risk compared to the index, but we also get a rate of return that is almost three times better than the one of the index.

An Approach of Advanced Optimistic Protocol Based on Time Dams

2013 ◽  
Vol 760-762 ◽  
pp. 2151-2155
Author(s):  
Zhong Jie Zhang ◽  
Jian Huang ◽  
Zhi Jia Wang
Keyword(s):  
Discrete Event Simulation ◽  
Time Synchronization ◽  
Discrete Event ◽  
Time Warp ◽  
New Approach ◽  
Event Simulation ◽  
The One ◽  
Better Than

Time Synchronization is a key technique which synchronizes the LPs (Logic processes) of PDES (Parallel and Discrete Event Simulation). After having described shortcomings of the existing algorithms for Time Synchronization, this thesis mainly proposes a new approach based on time dams. It introduces the concept of Time Dams Algorithm and presents its realization. Moreover, the performance of TD (Time Dams) Algorithm is compared with the one of TW (Time Warp) Algorithm through the use of PHOLD model in experiments. Finally, the experiment results state that TD performs better than TW under most conditions.

scholarly journals Analysis of Arbitrary Reflector Antennas Applying the Geometrical Theory of Diffraction Together with the Master Points Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-13
Author(s):  
María Jesús Algar ◽  
Jose-Ramón Almagro ◽  
Javier Moreno ◽  
Lorena Lozano ◽  
Felipe Cátedra
Keyword(s):  
Method Of Moments ◽  
Near Field ◽  
Complex Geometries ◽  
Geometrical Theory ◽  
Reflector Antennas ◽  
New Approach ◽  
Sampling Points ◽  
Time Requirements ◽  
Geometrical Theory Of Diffraction ◽  
A New Technique

An efficient approach for the analysis of surface conformed reflector antennas fed arbitrarily is presented. The near field in a large number of sampling points in the aperture of the reflector is obtained applying the Geometrical Theory of Diffraction (GTD). A new technique named Master Points has been developed to reduce the complexity of the ray-tracing computations. The combination of both GTD and Master Points reduces the time requirements of this kind of analysis. To validate the new approach, several reflectors and the effects on the radiation pattern caused by shifting the feed and introducing different obstacles have been considered concerning both simple and complex geometries. The results of these analyses have been compared with the Method of Moments (MoM) results.

Texture Segmentation of Jacquard Fabric Image Based on Multiresolution Markov Random Field

2011 ◽  
Vol 101-102 ◽  
pp. 496-499
Author(s):  
You Cheng Tong ◽  
Yang Zhang ◽  
Jun Zhou Yao
Keyword(s):  
Iterative Process ◽  
Texture Segmentation ◽  
Automated Segmentation ◽  
Map Estimation ◽  
Initial Value ◽  
New Approach ◽  
Markov Random ◽  
Variable Weighting ◽  
The One ◽  
Better Than

In order to develop an automated segmentation system for jacquard fabric images, a new approach based on MRMRF algorithm with variable weighing parameter is proposed in this paper. Firstly the variable weighting parameter different to the one in traditional MRMRF is described, which can provide a more accurate vector. The next step is MAP estimation and the model for texture segmentation. During this iterative process the initial value is big enough to learn more accurate parameters of feature energy. With the iterative number going on, the value will decrease and stop decreasing when the iterative number comes to some degree. Lastly the experiment results show that the new approach works better than the traditional method with constant weighing parameter.

Subjective Time Preference and Willingness to Pay for an Energy-Saving Durable Good

2001 ◽  
Vol 32 (3) ◽  
pp. 133-141 ◽  
Author(s):  
Gerrit Antonides ◽  
Sophia R. Wunderink
Keyword(s):  
Willingness To Pay ◽  
Energy Saving ◽  
Subjective Time ◽  
Durable Good ◽  
Discount Function ◽  
Hyperbolic Discount ◽  
The One ◽  
Two Parameter ◽  
Difference Effect ◽  
Better Than

Summary: Different shapes of individual subjective discount functions were compared using real measures of willingness to accept future monetary outcomes in an experiment. The two-parameter hyperbolic discount function described the data better than three alternative one-parameter discount functions. However, the hyperbolic discount functions did not explain the common difference effect better than the classical discount function. Discount functions were also estimated from survey data of Dutch households who reported their willingness to postpone positive and negative amounts. Future positive amounts were discounted more than future negative amounts and smaller amounts were discounted more than larger amounts. Furthermore, younger people discounted more than older people. Finally, discount functions were used in explaining consumers' willingness to pay for an energy-saving durable good. In this case, the two-parameter discount model could not be estimated and the one-parameter models did not differ significantly in explaining the data.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

Evaluation for estimating of the PDF and the CDF of Generalized Inverted Exponential Distribution with Application in Industry

2020 ◽  
pp. 507-522
Author(s):  
Parisa Torkaman
Keyword(s):  
Least Squares ◽  
Exponential Distribution ◽  
Mean Squared Error ◽  
Weighted Least Squares ◽  
Real Data ◽  
Minimum Variance ◽  
Cumulative Distribution ◽  
Estimation Methods ◽  
Data Set ◽  
Better Than

The generalized inverted exponential distribution is introduced as a lifetime model with good statistical properties. This paper, the estimation of the probability density function and the cumulative distribution function of with five different estimation methods: uniformly minimum variance unbiased(UMVU), maximum likelihood(ML), least squares(LS), weighted least squares (WLS) and percentile(PC) estimators are considered. The performance of these estimation procedures, based on the mean squared error (MSE) by numerical simulations are compared. Simulation studies express that the UMVU estimator performs better than others and when the sample size is large enough the ML and UMVU estimators are almost equivalent and efficient than LS, WLS and PC. Finally, the result using a real data set are analyzed.

Designing Women

2018 ◽  
Author(s):  
J. E. Smyth
Keyword(s):  
Working Women ◽  
Costume Design ◽  
Creative Force ◽  
Women's Fashion ◽  
The One ◽  
Studio Era ◽  
Average Woman ◽  
Better Than

During the early 1940s, journalists observed that after years of men controlling women’s fashion, Hollywood had become “a fashion center in which women designers are getting to be a big power.” In a town where “the working girl is queen,” it was women who really knew how to dress working women. Edith Head’s name dominates Hollywood costume design. Though a relatively poor sketch artist who refused to sew in public, Head understood what the average woman wanted to wear and knew better than anyone how to craft her image as the-one-and-only Edith Head. However, she was one of many women who designed Hollywood glamour in the studio era. This chapter juxtaposes Head’s career with that of a younger, fiercely independent designer who would quickly upstage Head as a creative force. In many senses, Dorothy Jeakins’s postwar career ascent indicated the waning of the Hollywood system and the powerful relationship between female designers, stars, and fans.

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