We evaluated a solution to seismic deghosting that deghosts the low-frequency components of the seismic pressure data. In an approximation that neglected the dependence on wavenumbers, the low-frequency deghosted pressure field was computed trace-by-trace as the sum of the pressure field and its scaled temporally integrated and temporally differentiated fields. We gave simple numerical examples...

A borehole tiltmeter with a sensitivity of a few nanoradians is described. It is composed of two orthogonal horizontal pendulums with free periods of 1 s. The pendulums are insensitive to barometric pressure fluctuations, and the measured temperature coefficient is less than 30 nrad/°C. The range of the pendulums is about ±5 μ rad, and their response is linear within 1% and stable over several ...

the ever increasing rate of power consumption has led to an increase in public exposure to extremely low frequency magnetic fields (elf-mfs) and brought severe concerns about their health effects. considering previous studies and the facts about potential health effects of these fields, the present study aimed to evaluate the elf-mf flux densities from power distribution lines near hospitals i...

Usually the generalized sidelobe canceller (GSC) beamformer requires additional highpass pre-filtering due to insufficient suppression of low frequency directional interference, and it deteriorates the bandwidth quality of speech enhancement, especially for small size microphone array. This paper proposes a new GSC beamformer with multiple frequency dependent norm-constrained adaptive filters (...

Many questions in economics involve long-run or “trend” variation and covariation in time series. Yet, time series of typical lengths contain only limited information about this long-run variation. This paper suggests that long-run sample information can be isolated using a small number of low-frequency trigonometric weighted averages, which in turn can be used to conduct inference about long-r...

This thesis concerns the application of electromagnetic wave propagation to the problem of indoor radiolocation. Determining the location of people and objects relative to their environment is crucial for asset tracking, security, and human-computer interface (HCI) applications. These applications may be as simple as tracking the location of a valuable shipping carton or detecting the theft of ...

Abstract Vibration and noise control are among the classical engineering problems that still draw extensive research interest today. Multiple active passive techniques to resolve these have been reported, however, challenges remain substantial. The recent surge of activities on acoustic metamaterials for vibration testimony fact metamaterial is no longer limited pure theoretical concepts. For o...

   Nowadays, one of the most important blocks in telecommunication circuits is the frequency synthesizer and the frequency multipliers. Phase-frequency detectors are the inseparable parts of these circuits. In this paper, it has been attempted to design two new structures for phase-frequency detectors in QCA nanotechnology. The proposed structures have the capability of detecting the phase ...