seismic waves are non-stationary due to its propagation through the earth. time-frequency transformsare suitable tools for analyzing non-stationary seismic signals. spectral decomposition can reveal thenon-stationary characteristics which cannot be easily observed in the time or frequency representationalone. various types of spectral decomposition methods have been introduced by some researche...

This paper analyses the frequency support characteristics of multi-terminal VSC-HVDC (MTDC) schemes using the energy transferred from wind turbine rotating mass and other AC systems. An alternative coordinated control (ACC) scheme, which gives priority to a frequency versus active power droop fitted to onshore VSCs is proposed to: (i) transfer wind turbine recovery power to undisturbed AC grids...

Detecting shadows is needed for object detection methods because shadows often have a harmful effect on the result. Shadow detection methods based on shadow models are proposed. The shadow model should be updated to detect shadows which are not included in the learning data. In this paper, a new method for updating the shadow model for shadow detection is proposed. The proposed method models sh...

The presence of physical obstacles and radio interference results in the so called “shadow regions” in wireless networks. When a mobile station roams into a shadow region, it loses its network connectivity. In cellular networks, in order to minimize the connection unreliability, careful cell planning is required to prevent the occurrance of the shadow regions in the first place. In 802.11b/g wi...

Shadow banking is a term that came out of the financial crisis of 2007-2009. There is a belief that shadow banking was one of the crisis reasons. Because the excessive expansion of shadow banking endangers the financial stability of countries, this paper examines the impact of shadow banking on financial stability using data from 14 countries of the G20 during 2002-2018. We divided countries in...

The apparent angular size of the shadow a black hole in an expanding Universe is redshift-dependent. Since cosmological redshifts change with time - known as redshift drift all redshift-dependent quantities acquire time-dependence, and fortiori so do shadows. We find mathematical description show that amplitude this effect order $10^{-16}$ per day for M87$^{\star}$. While small, we argue its no...

The head-related transfer function (HRTF) for distant sources is a complicated function of azimuth, elevation and frequency. This paper presents simple geometric models of the head and torso that provide insight into its low-frequency behavior, especially at low elevations. The head-and-torso models are obtained by adding both spherical and ellipsoidal models of the torso to a classical spheric...

In this paper we present an image-based algorithm to render visually plausible anti-aliased soft shadows in real time. Our technique employs a new shadow pre-filtering method based on an extended exponential shadow mapping theory. The algorithm achieves faithful contact shadows by adopting an optimal approximation to exponential shadow reconstruction function. Benefiting from a novel overflow f...

Shadows are illuminated as a result of Rayleigh scattering phenomenon, which happens to be more effective for small wavelengths of light. We propose utilization of false color images for shadow detection, since the transformation eliminates high frequency blue component and introduces low frequency near-infrared channel. Effectiveness of the approach is tested by using several shadow-variant te...

Shadows provide the human visual system with important cues to sense spatial relationships in the environment we live in. As such they are an indispensable part of realistic computer-generated imagery. Unfortunately, visibility determination is computationally expensive. Image-based simplifications to the problem such as Shadow Maps perform well with increased scene complexity but produce artif...