نتایج جستجو برای: which reduce their acoustic efficiency

تعداد نتایج: 5217707  

2013
Diego Llusia Miguel Gómez Mario Penna Rafael Márquez

Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitat...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی 1389

cultural iran is a scope that is more extended than the political territories of iran as a political unit. this concept means that cultural geography(mehdi moghanlo-1383-1) of iran is greater than its political geography which, according to history, has a long history extending west-east from kandahar to the euphrates and north-south from the persian gulf to the caucasus including transoxiana a...

2015
S. Suganthi S. Sathya

Underwater acoustic communication is a technique of sending and receiving message below water. Under water communication is difficult due to factors like multi-path propagation, time variations of the channel, small available bandwidth and strong signal attenuation, especially over long ranges. In underwater communication there are low data rates compared to terrestrial communication. Since und...

Journal: :Sustainability 2021

Despite the long-term experience in application of noise walls, uncertainty wall panel service life efficiency is almost equal between panels built from established and new materials, which are—because desire to increase sustainability walls—developing at an ever-faster pace. The presented meta-analysis data collected during a systematic review concrete, metal, wood panels’ acoustic non-acousti...

2017
Senlin Zhang Huayan Chen Meiqin Liu Qunfei Zhang

Target tracking is one of the broad applications of underwater wireless sensor networks (UWSNs). However, as a result of the temporal and spatial variability of acoustic channels, underwater acoustic communications suffer from an extremely limited bandwidth. In order to reduce network congestion, it is important to shorten the length of the data transmitted from local sensors to the fusion cent...

Journal: :iranian journal of fuzzy systems 2012
s. r. mousavi-aghdam m. b. b. sharifian m. r. banaei

this paper presents a new control structure to reduce torque ripple in switched reluctance motor. although srm possesses many advantages in motor structure, it suers from large torque ripple that causes some problems such as vibration and acoustic noise. in this paper another control loop is added and torque ripple is de ned as an objective function. by using fuzzy sliding mode strategy, the dc...

2013
Huang Mei Haixin Sun Cheng En Xiaoyan Kuai Xiaoka Xu

Orthogonal frequency-division-multiplexing (OFDM) has been actively pursued in underwater acoustic communications. However, OFDM is extremely sensitive to carrier frequency offset (CFO) which cause significant problems. The utilization and performance of traditional channel estimation are poor. Although underwater acoustic communication was recently the focus of research, literatures on joint i...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1392

like any other learning activity, translation is a problem solving activity which involves executing parallel cognitive processes. the ability to think about these higher processes, plan, organize, monitor and evaluate the most influential executive cognitive processes is what flavell (1975) called “metacognition” which encompasses raising awareness of mental processes as well as using effectiv...

1999
Peter Eneroth Steven Gay Tomas Gänsler Jacob Benesty

Teleconferencing systems employ acoustic echo cancelers to reduce echoes that results from the coupling between loudspeaker and microphone. To enhance the sound realism, two-channel audio is necessary. However, stereophonic acoustic echo cancellation is more difficult to solve because of the necessity to uniquely identify two acoustic paths, which becomes problematic since the two excitation si...

Journal: :Lab on a chip 2015
Sixing Li Xiaoyun Ding Zhangming Mao Yuchao Chen Nitesh Nama Feng Guo Peng Li Lin Wang Craig E Cameron Tony Jun Huang

Cell/bead washing is an indispensable sample preparation procedure used in various cell studies and analytical processes. In this article, we report a standing surface acoustic wave (SSAW)-based microfluidic device for cell and bead washing in a continuous flow. In our approach, the acoustic radiation force generated in a SSAW field is utilized to actively extract cells or beads from their orig...

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