Nonlinear dynamics in the Jupiter magnetosphere: implications of dust-acoustic cnoidal mode

Different types of waves and their nature in the Jovian middle magnetosphere are still not clear or specified. For this purpose, a generalized hydrodynamic model for an arbitrary amplitude dust-acoustic waves is built for true Jovian magnetosphere. The plasma system consists of positive dust grains, Maxwellian ions and electrons. An evolution equation containing a Sagdeev potential is derived, and its numerical analysis is presented. Unexpectedly, the given data yielded cnoidal waves only with positive potential. The effect of the external magnetic field, Mach number, and directional cosine parameters are studied and manipulated. We think that the present results are important in realizing the main waves in the Jovian magnetosphere, and the possible correlation to its particlesístability and pole acoustic waves.

Wireless Propagation Multipaths using Spectral Clustering and Three-Constraint Affinity Matrix Spectral Clustering

This study focused on spectral clustering (SC) and three-constraint affinity matrix spectral clustering (3CAM-SC) to determine the number of clusters and the membership of the clusters of the COST 2100 channel model (C2CM) multipath dataset simultaneously. Various multipath clustering approaches solve only the number of clusters without taking into consideration the membership of clusters. The problem of giving only the number of clusters is that there is no assurance that the membership of the multipath clusters is accurate even though the number of clusters is correct. SC and 3CAM-SC aimed to solve this problem by determining the membership of the clusters. The cluster and the cluster count were then computed through the cluster-wise Jaccard index of the membership of the multipaths to their clusters. The multipaths generated by C2CM were transformed using the directional cosine transform (DCT) and the whitening transform (WT). The transformed dataset was clustered using SC and 3CAM-SC. The clustering performance was validated using the Jaccard index by comparing the reference multipath dataset with the calculated multipath clusters. The results show that the effectiveness of SC is similar to the state-of-the-art clustering approaches. However, 3CAM-SC outperforms SC in all channel scenarios. SC can be used in indoor scenarios based on accuracy, while 3CAM-SC is applicable in indoor and semi-urban scenarios. Thus, the clustering approaches can be applied as alternative clustering techniques in the field of channel modeling.

Partitioning of Terrain Features Based on Roughness

Surface roughness is a key parameter that reflects topographic characteristics and influences surface processes, and characterization of surface roughness is a fundamental problem in geoscience. In recent years, although there have been basic studies on roughness, few studies have compared the concept and quantification of roughness, and there have been few studies that have evaluated the ability of partition terrain features. Based on 1″ resolution Shuttle Radar Topography Mission (SRTM) data and previous studies, we selected the Qinba Mountain region of China and its adjacent areas as our study area, and used 13 different roughness algorithms to extract roughness in this study. Using spatial patterns and statistical distributions, the results were analyzed, and the best algorithm suited to partitioning terrain features was selected. We then evaluated the ability of the algorithm to distinguish the terrain morphology. The results showed the following: (1) The 13 algorithms were able to be classified into four types, that is, gradient (SLOPE), relief (root mean squared height, RMSH), local vector (directional cosine eigenvalue, DCE) and power-spectral (two-dimensional continuous wavelet transform, 2D CWT). (2) The SLOPE and RMSH algorithms were better able to express and distinguish terrain, as they were able to macroscopically distinguish between four types of terrain in the study areas. Based on power-spectral methods, 2D CWT had the same discrimination ability as the first two methods following a normalization transform, whereas the DCE method had a general effect and could only distinguish two types of terrain. (3) Different roughness algorithms had their own applicability for different terrain areas and application directions.

Enhanced 2D-DOA Estimation for Large Spacing Three-Parallel Uniform Linear Arrays

An enhanced two-dimensional direction of arrival (2D-DOA) estimation algorithm for large spacing three-parallel uniform linear arrays (ULAs) is proposed in this paper. Firstly, we use the propagator method (PM) to get the highly accurate but ambiguous estimation of directional cosine. Then, we use the relationship between the directional cosine to eliminate the ambiguity. This algorithm not only can make use of the elements of the three-parallel ULAs but also can utilize the connection between directional cosine to improve the estimation accuracy. Besides, it has satisfied estimation performance when the elevation angle is between 70° and 90° and it can automatically pair the estimated azimuth and elevation angles. Furthermore, it has low complexity without using any eigen value decomposition (EVD) or singular value decompostion (SVD) to the covariance matrix. Simulation results demonstrate the effectiveness of our proposed algorithm.

IDENTIFICATION OF EXPLORATION GOLD TARGETS IN THE ALTA FLORESTA GOLD PROVINCE, MATO GROSSO STATE, BRAZIL, BASED ON AN INTEGRATED INTERPRETATION OF MAGNETIC AND GEOELECTRICAL DATA

ABSTRACT. The significant amount of filonean bodies in the gold mining area of Flor da Serra, east portion of the Alta Floresta Gold Province, located in the state of Mato Grosso, Brazil, and the production history of the area indicates high potential for gold exploration. Our work aimed to identify new gold exploration targets in this area through the analysis and interpretation of geoelectric and magnetic data, constrained by descriptions of drill core samples and prospecting pits. The geophysical survey consisted of the acquisition of geoelectrical (induced polarization/resistivity) and magnetic data at deposit scale. Anomalous values of chargeability and resistivity defined zones of intense silicification and quartz-sericite-pyrite alteration closely related to a disseminated ore type, extending far below the saprolite-bedrock interface. The amplitude of the analytic signal of the magnetic anomalous field allowed the identification of granitic intrusive stock within heterogeneous basement. Magnetic structures were extracted from magnetic anomalies reduced to the equator over which directional features were highlighted after application of a directional cosine filter and upward continuation. The structural pattern is associated with different crustal levels, controls the main filonean bodies of the region and is attached to quartzsericite- pyrite alteration. The integrated interpretation of main structural lineaments; zones of high chargeability/resistivity; detailed mapping of deactivated mining pits; and boundaries of the intrusion zone led to the definition of some prospective gold targets.Keywords: magnetometry, induced polarization, resistivity, gold deposits. RESUMO. A quantidade significativa de corpos filoneanos na área de mineralizações auríferas de Flor da Serra, porção leste da Província Aurífera de Alta Floresta (PAAF), localizada no estado de Mato Grosso, e o histórico de produção dessa área indicam alto potencial para exploração de ouro. Este trabalho teve como objetivoidentificar novos alvos de exploração de ouro nesta área, através da análise e interpretação dos dados geoelétricos e magnéticos, vinculados por descrições de amostras de testemunhos de perfuração e de cavas garimpeiras. O levantamento geofísico consistiu na aquisição de dados geoelétricos de polarização induzida/resistividade e magnéticos em escala de depósito. Valores anômalos de cargabilidade e zonas de resistividade definiram intensa silicificação e alteração quartzo-sericita-pirita (QSP) fortemente relacionadas a um tipo de minério disseminado, estendendo-se muito abaixo da interface saprólito-rocha. A amplitude do sinal analítico do campo magnético anômalo permitiu a identificação de um stock granítico intrusivo dentro de um embasamento heterogêneo. Estruturas magnéticas foram extraídas de anomalias magnéticas reduzidas ao equador magnético, sobre as quais as principais feições direcionais foram destacadas após aplicação de um filtro de cosseno direcional e continuação para cima. O padrão estrutural, que está associado a diferentes níveis crustais, controla os principais corpos filoneanos da região e está ligado à alteração de QSP. A interpretação integrada dos principais lineamentos estruturais; zonas de alta cargabilidade/resistividade; mapeamento detalhado de cavas garimpeirasdesativadas; e zona limítrofe da intrusão, levou à definição de alguns alvos potenciais para exploração de ouro.Palavras-chave: magnetometria, polarização induzida, resistividade, depósitos de ouro.

Self Localization Using a 9DOF IMU Sensor With a Directional Cosine Matrix

In the field of robotics, the most essential requirement for successful navigation is an accurate and numerically inexpensive method for self-localization. This paper presents a method that exploits the principles of directional cosines to setup a rotation matrix to deal with a closed loop PI feedback based model. The system uses a 9 degree of freedom (9DOF) sensor and exploits the benefits of the accuracy of a 3-axis gyroscope by leveraging the measurement of a 3-axis accelerometer and 3-axis magnetometer, which compensates and corrects the accumulative drift generated by integrating the gyroscope velocity measurements. The results show that the method is relatively accurate with a small level of error when compared to vision based glyph recognition and tracking methods for self-localization and is a sustainable method for removing accumulative drift.