• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.998-1007
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• 2018

The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

• Journal of Sensor Science and Technology
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• v.17 no.4
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• pp.317-324
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• 2008

This paper presents an optical doppler tomography(ODT) system using a speaker as a method to achieve depth measurement in a flowing sample. The use of the speaker provides easy implementation with a low cost. The nonlinear characteristics of the speaker has hindered its adaptation because it produces inconsistent fringe frequencies at different depths. This paper reports an adaptive algorithm to compensate the nonlinear characteristics, and could, resultantly, acquire the Doppler frequency shift caused by the sample. The experiment utilizes a flowing scattering particle solution in a capillary tube at a certain flow rate. The Doppler frequency profile over the lumen was calculated by using spectrogram method. and we obtained the velocity image of the sample.

• International Journal of Knowledge Content Development & Technology
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• v.14 no.2
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• pp.81-97
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• 2024

The study investigated computer literacy skills as a determinant of electronic reference sources utilization among selected secondary school students in Ado-Odo Ota Local Government, Ogun State, Nigeria. Four specific objectives with conforming research questions guided the study. Descriptive survey research design was adopted for the study. The population of the study comprises of SSS3 students of the three selected Community Secondary Schools in Ado Odo Ota. A sample size of 150 was used for the study. The instrument for data collection was a self-developed structured questionnaire. Data collected was analyzed using frequency and percentages. Findings of the study revealed that majority of secondary school students were not aware of the availability of electronic reference sources. It also revealed that the level of their computer literacy skills was below average. Majority of them have never used computer before and the few of them that have used computer before used it in their homes, their friend's homes or in the cyber café. It was found that lack of formal training on the use of electronic reference sources, lack of access to computer, lack of awareness of availability of electronic reference sources, lack of funds for internet subscriptions, over dependency on printed reference sources and lack of motivation to use electronic reference sources were the major hindrances to the use of electronic reference sources among secondary school students. It was recommended that the school librarians and teachers should play a role in creating awareness among secondary school students about the availability of online/ electronic reference sources among others.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.83-85
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• 2016

C-RAN (Cloud Radio Access Network) structure is the most popular approach for 5G stander, it employs CoMP (Coordinated Multiple Points Transmission/Reception) to enhance frequency utilization and increase throughput for cell-edge users. C-RAN mainly includes two parts: baseband units (BBU) and remote radio heads (RRH). In this paper we propose a new resource block allocation (spectrum allocation) scheme by the permutation and combination of BBUs, and we also use the CoMP (Coordinated Multiple Points Transmission/Reception) technique according to the different environment to improve the spectrum utilization and reduce resource waste in different environment. The simulation results expound that the scheme significantly enhances throughput and improves the spectrum utilization.

• Journal of Communications and Networks
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• v.11 no.5
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• pp.473-479
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• 2009

Conventional frequency domain equalization (FDE) schemes were originally devised for quasi-static channels. Thus, such equalization schemes could suffer from significant performance degradation in fast-fading channels. This paper proposes a frequency domain equalization algorithm to mitigate the effect of fast time-varying fading. First, a mathematical expression is derived to quantify the total interference resulting from the time variation of the channel. Then, the proposed approach attempts to eliminate the effect of time-variations of the channel. This cancellation allows efficient use of the classical FDE structures in fast time-varying fading environments, although they are built upon the quasi-static channel model. Simulation results of bit-error-rate performance are provided to demonstrate the effectiveness of the proposed algorithm.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.466-472
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• 2007

Single carrier block transmission with frequency domain equalization(SC-FDE) has been shown to be a promising candidate in ultra-wideband(UWB) communications. In this paper, we analyze the performance of SC-FDE over UWB communications with channel estimation error. The probability density functions of the frequency domain minimum mean-squared error(MMSE) equalizer taps are derived in closed form. The error probabilities of single carrier block transmission with frequency domain MMSE equalization under imperfect channel estimation are presented and evaluated numerically. Compared with the simulation results, our semi-analytical analysis yields fairly accurate bit error rate performance, thus validating the use of the Gaussian approximation method in the performance analysis of the SC-FDE system with channel estimation error.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1239-1243
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• 2009

To evaluate the structural integrity of the nuclear seismic category penetration cooling water pump under the seismic service conditions the seismic analysis was performed in accordance with IEEE-STD-344 code. The finite element computer program, ANSYS, Version 10.0, is used to perform both a mode frequency analysis and an equivalent static seismic analysis of the pump assembly. The mode frequency analysis results show the fundamental natural frequency is greater than 33 Hz and does not exist in seismic range, thus justifying the use of the static analysis. The stresses resulted from various loadings and their combinations are within the allowable limits specified in the above mentioned IEEE code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the IEEE code. Accordingly the structural integrity on the pump assembly was proved.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.361-368
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• 2010

ACROSS device, which is composed of an implantable microphone, a signal processor, and a vibrating transducer, is a fullyimplantable middle ear hearing device(F-IMEHD) for the recovery of patients with hearing loss. And since a microphone is implanted under skin and tissue at the temporal bones, the amplitude of the sound wave is attenuated by absorption and scattering. And the vibrating transducer attached to the ossicular chain caused also the different displacement from characteristic of the stapes. For the gain control of auditory signals, most of implantable hearing devices with the digital audio signal processor still apply to fitting rules of conventional hearing aid without regard to the effect of the implanted microphone and the vibrating transducer. So it should be taken into account the effect of the implantable microphone and the vibrating transducer to use the conventional audio fitting rule. The aim of this study was to measure gain characteristics caused by the implanted microphone and the vibrating transducer attached to the ossicle chains for the gain compensation of ACROSS device. Differential floating mass transducers (DFMT) of ACROSS device were clipped on four cadaver temporal bones. And after placing the DFMT on them, displacements of the ossicle chain with the DFMT operated by 1 $mA_{peak}$ current was measured using laser Doppler vibrometer. And the sensitivity of microphones under the sampled pig skin and the skin of 3 rat back were measured by stimulus of pure tones in frequency from 0.1 to 8.9 kHz. And we confirmed that the microphone implanted under skin showed poorer frequency response in the acoustic high-frequency band than it in the low- to mid- frequency band, and the resonant frequency of the stapes vibration was changed by attaching the DFMT on the incus, the displacement of the DFMT driven with 1 $mA_{rms}$ was higher by the amount of about 20 dB than that of cadaver's stapes driven by the sound presssure of 94 dB SPL in resonance frequency range.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.448-454
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• 1999

This paper describes a new dc-ac inverter system which for achieving sinusoidal ac waveform makes use of parallel loaded high frequency resonant inverter consisting of full bridge. Each one of the pair of switches in the inverter is driven to synchronous output frequency and the other is driven to PWM signal with resonant frequency proportional to magnitude of sine wave. A forced discontinuous conduction mode is used to realize the quasi-sinusoidal pulse in each switching period. Therefore the inverter generates sinusoidal modulated output voltage including carrier frequency that is resonant frequency. Carrier frequency components of modulated output voltage is filtered by low pass filter. Since current through switches is always zero at its turn-on in the proposed inverter, low stress and low switching loss is achieved. Operating characteristics of the proposed system is analyzed in per unit system using computer simulation. The output voltage of if includes low harmonics and it is almost close to sine wave. Also, the theoretical analysis is proved through the experimental test.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.129-132
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• 2017

A conventional pulse oximeter has high power consumption; thus, its mobility is severely limited. In this paper, we discuss the drawbacks of the existing pulse oximeters and propose a new ultra-low-power pulse oximeter that supports wireless data transmission for remotely monitoring vital signs, such as peripheral capillary oxygen saturation (SpO2) and beats per minute (BPM). We could notably reduce power consumption by using a low-frequency single clock in all well-customized modules. Also, our device is publicly certified, and thus, possibly engaged in clinical trials for commercial use.