Vlbi research in the ”Radioastron” project: structure of the H2O maser in NGC 2071 IRS 1

Within the Radioastron interferometer scientific program, observational data of the H2O maser at a frequency of 22.2280 GHz in the NGC 2071 nebula were processed. A space radio telescope (SRT — 10 m) and three radio telescopes of the ground network: RT — 32 m (Medicina, Italy), RT — 32 m (Torun, Poland) and RT —64 m (Kalyazin, RF) took part in the observations. A map of the maser spot distribution has been obtained, where there are 13 spatial components with VLSR in the range 4.7 — 20.5 km/s. Correlation is observed on ground-space baselines for the component on VLSR = 14.3 km/s. Based on the visibility function dependence analysis from the baseline projection values, there was proposed a twocomponent model of this component spatial structure with the dimensions of the extended and compact constituent of 4 and 0.06 msec, i.e. 1.56 and 0.023 au, respectively.

The design and development of an automatic transmission solenoid tester for wheeled vehicles

Solenoids are the most critical components in automatic transmissions. They are used to control the shift points, clutch locking, or pressure regulation of automatic transmissions. Since the number, type, and order of the solenoids all differ when they are used in different vendor’s automatic transmissions, making accurate normal/abnormal decisions for solenoids is very difficult, as it can lower the maintenance quality, to waste labor and material cost, and even reduce driving safety. This article proposes an “abnormal” inspecting method (i.e. for abnormality) for solenoids with high inspect ability and develops a learnable automatic transmission solenoid tester. This tester can perform solenoid testing on multiple channels at the same time. The test result statistics for all channel solenoids tested are generated automatically. It also provides visibility for users to view the difference comparisons of testing curves of temperature, pressure, voltage, current, and resistance on a graphical screen. The curve visibility function will be helpful for the solenoid diagnosis of abnormal or fault reasons.

Visibility intervals between two artificial satellites under the action of Earth oblateness

This paper presents an analytical method to determine the rise-set times of satellite-satellite visibility periods in different orbits. The Visibility function in terms of the orbital elements of the two satellites versus the time were derived explicitly up to e4. The line-of-sight corrected for Earth Oblateness up to J2, were considered as a perturbation to the orbital elements. The visibility intervals of the satellites were calculated for some numerical examples in order to test the results of the analytical work.

Calculation of line of site periods between two artificial satellites under the action air drag

In a previous (herein referred to as Ammar, Amin and Hassan Paper [1]) the statement of the problem was formulated and the basic visibility function between two satellites in terms of the orbital elements and time were derived. In this paper the perturbing effect due to drag force on the visibility function were derived explicitly up to O(e4), by using Taylor’s expansion for the visibility function about certain epoch. We determine the rise and set times of the satellites through the sign of the visibility function. Numerical examples were worked out for some satellites in order to check the validity of the work.

Multiresolution SVD Based Image Watermarking Scheme Using Noise Visibility Function

This paper presents a robust and imperceptible methodology of watermark embedding. It uses two vital techniques, firstly the Multi-Resolution Singular Value Decomposition (MR-SVD) and an image adaptive algorithm on the lines of the human visual system (HVS), called Noise Visibility Function (NVF). This is a special type of Singular Value Decomposition (SVD) with cell based operation for multi-resolution behavior like wavelets. So, by embedding the watermark in the Eigen values the robustness of the scheme is enhanced. While for the imperceptibility the NVF has been employed here. The optimal areas for embedding the watermark are characterized by it based on the local smooth or rough textures detected on the MR-SVD image based on the wavelet strength at sub bands. For imperceptibility, the algorithm has been tested on standard test images and different types of attacks for robustness to obtain encouraging results. This incorporates MR-SVD for the first time with HVS based NVF function. Together they produce better results.