• The Journal of the Acoustical Society of Korea
• /
• v.39 no.6
• /
• pp.533-540
• /
• 2020

A total length of sperm whales can be estimated by measuring the Inter-Pulse Interval(IPI) of their clicks composed by multiple pulses. The IPI is caused by the two-way travel time of the sound transmission in the spermaceti within the whale head. Therefore, the IPI can be used to measure the whale's total length based on allometric relationships between head and body length. In this paper, the click signals recorded in the East Sea, Korea in 2017 were analyzed to estimate the size of sperm whales. The size of sperm whales calculated by the relationship between IPI and body length was 9.9 m to 10.9 m, which is corresponding to the size of an adult female or a juvenile male sperm whale. This non-lethal acoustic method has been demonstrated to accurately estimate the sperm whale size, and can provide useful information for domestic sperm whale monitoring.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.12C
• /
• pp.1192-1199
• /
• 2003

In this paper, we investigate the effect of pulse repetition frequency (PRF) and slot interval on the throughput performance of the ultra wide band (UWB) wireless communication system in multi-path channels, and based on these observations, a data throughput control using PRF and slot interval is proposed for maximizing the effective throughput. Recently, due to many desirable features of the UWB system, it has drawn much attention especially for short-range high-speed data transmission. The UWB system has two parameters to determine its data throughput; pulse repetition frequency and slot interval. In the multi-path channel with additive white Gaussian noise, the UWB system suffers from the inter-pulse interference (IPI) and noise, which result in degradation of system performance. The UWB system can vary the two parameters to maintain and/or improve the system performance. In this paper, we demonstrate the effects of the two parameters on the data throughput of the UWB system in various multi-path indoor channels through computer simulation, and show that the variable data rate approach designed based on the observations is superior to the fixed data rate one in terms of effective throughput performance.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.3
• /
• pp.335-342
• /
• 1988

In this paper, we proposed a new algorithm for EMG low frequency analysis. Through the power spectrum analysis of Gaussian's, Gamma's and Erlang's PDF(probability density function) based on the proposed algorithm, the proper PDF of IPI (inter pulse interval) representing the firing rate of muscle was suggested. In order to verify the proposed algorithm EMG signals of masseter and biceps muscle were detected by surface electrode and its power spectrum analysis was performed. The experimental results are compared with the computer simulaiton. As a result, the masseter muscle's IPI was fitted by Gamma PDF, having a 10Hz fundamental frequency including n(1+\ulcornerfp high harmnic frequency on 10% MVC(maximum voluntary contaraction). And the biceps muscle's IPI was fitted by Gaussian PDF, also it have a 14Hz fundamental frequency.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.4A
• /
• pp.352-360
• /
• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.3
• /
• pp.632-640
• /
• 2007

The low force estimation method of skeletal muscle was proposed by using ICA(independent component analysis) and neuro-transmission model. An EMG decomposition is the procedure by which the signal is classified into its constituent MUAP(motor unit action potential). The force index of electromyography was due to the generation of MUAP. To estimate low force, current analysis technique, such as RMS(root mean square) and MAV(mean absolute value), have not been shown to provide direct measures of the number and timing of motoneurons firing or their firing frequencies, but are used due to lack of other options. In this paper, the method based on ICA and chemical signal transmission mechanism from neuron to muscle was proposed. The force generation model consists of two linear, first-order low pass filters separated by a static non-linearity. The model takes a modulated IPI(inter pulse interval) as input and produces isometric force as output. Both the step and random train were applied to the neuro-transmission model. As a results, the ICA has shown remarkable enhancement by finding a hidden MAUP from the original superimposed EMG signal and estimating accurate IPI. And the proposed estimation technique shows good agreements with the low force measured comparing with RMS and MAV method to the input patterns.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.11
• /
• pp.55-58
• /
• 1997

In this paper, we study a signal processing method which extracts each MUAP(motor unit action potential) from EMG(Electromyogram) interference pattern or clinical diagnostic purposes. First of all, differential digital filtering is selected or eliminating the spike components of the MUAP's from the background noise. And, the algorithm identifies the spikes over the certanin threshold by template matching in frequency domain. After missing or false firing actor is cut off at the IPI(inter pulse interval) histogram, we averages the MUAP waveforms from the raw signal using the identified spikes as triggers, and Finally, measures their amplitudes, durations, and numbers of phases. Specially, We introduce algorithm performed by template matching in the frequency domain. A typical 3-s signal recorded from the biceps brachii muscle using a conventional needle electrode during a isometric contraction is used. Finally, the method decomposed five simultaneous active MUAP's from original EMG signal.

• Korean Journal of Ecology and Environment
• /
• v.49 no.4
• /
• pp.385-392
• /
• 2016

Geographical isolation may lead to the populations having different ecological characteristics. Geographic isolation have been known to cause echolocation call differences in bats. In order to look at geographic differences of echolocation calls of Great Horseshoe Bats (Rhinolophus ferrumequinum), populations of inland and Jeju island habitats were examined in Korea. The study areas were some abandoned mines in the inland and caves of Jeju island, which were known as rest sites of Great Horseshoe Bats during the active season. Recording was done in two ways: Hand-held, Free-flying. Recording pulse was analyzed into five parameters: Maximum Frequency (FMAX), Minimum Frequency (FMIN), Peak Frequency (PF), Duration (D), Inter pulse Interval (IPI). Interestingly, The present study shows that the difference in echolocation between the inland and island populations. The PF of bats inhabited inland was 69 kHz. but, the PF of bats inhabited island (Jeju) was 71 kHz. There was a difference between regions. Discriminant analyses also showed clear difference between the inland and the island populations. Especially, PF of Korea population is lower than that of Europe (82 kHz) and higher than that of Japan (65 kHz).