• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.27-38
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• 2011

In this paper, we propose a multiple access scheme using MHP(Modified Hermite Polynomial) pulse and ternary code for high-data and low-data rate for Out-body WBAN(Wireless Body Area Network). To satisfy the requirement of WBAN system, UWB-IR has been considered as a promising candidate for Out-body WBAN. The proposed multiple access scheme, using orthogonal MHP pulse and ternary code sets, reduces multi-user interference and distinguishes user signal from multi-user signals. We propose two algorithms for synchronous and asynchronous WBAN system. The symbol is constructed by MHP pulses and time hopping duration to reduce multi-user interference in the synchronous WBAN system. The symbol also is constructed by ternary code to avoid collision between pulse trains in the asynchronous WBAN system. The results of the proposed multiple access scheme show a clear improvement of BER.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1153-1160
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• 2003

In this paper, the performance of the UWB communication systems is analyzed in the presence of the Narrow Band Interference(NBI). UWB communication systems are modeled as using the Pulse Position Modulation(PPM). In this system, a Gaussian monocycle is used as the received pulses. The NBI is considered as a zero-mean random process with a constant spectral power density over its whole bandwidth. We obtain the mathematical expressions for describing the effect of the NBI on the UWB system. And it can be shown that the suppression of the effect of NBI on the UWB systems is available by adjusting the PPM related parameter.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.365-373
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• 2003

This paper investigates the performance of M-ary pulse position modulation (PPM) multiuser ultra-wideband (UWB) communication systems in terms of symbol error rate (SER) over fading and additive white Gaussian noise (AWGN) channel. Based on Gaussian approximation for the multiple access interference, an expression for the signal-to-noise ratio (SNR) is derived for the UWB system. This expression is used to derive exact SER expressions for coherent UWB receivers. The effect of pulse selection on the SER of multiuser UWB system is studied. In addition to rectangular pulse, the 2nd derivative Gaussian waveform and Rayleigh pulses were considered. We show that the system capacity and/or SER performance can be significantly increased by using the monocycle pulse in fading channels.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.27-30
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• 2004

This paper has been designed the TDMG(Time Delay Multiple Gaussian) pulse generator for UWB systems and analyzed the characteristics of UWB impulse. Composite two equal Gaussian pulses in a difference time lag, and then investigated TDMG pulse and modeled mathematically. Designed the TDMG pulse generator by ADS(Advanced Design System) to embody by using actual element with such mathematical model. As well as, this paper finally proved an excellence of the TDMG pulse generator by performing analysis through simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.65-73
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• 2007

Pattern classification of single and multiple discharge sources was applied using a wavelet image signal method in which a feature extraction was applied using a hidden sub-image. A feature extracting method that used vertical and horizontal images using an MSD method was applied to an averaging process for the scale of pulses for the phase. A feature extracting process for the preprocessing of the input of a neural network was performed using an inverse transformation of the horizontal, vertical, and diagonal sub-images. A back propagation algorithm in a neural network was used to classify defective signals. An algorithm for wavelet image processing was developed. In addition, the defective signal was classified using the extracted value that was quantified for the input of a neural network.

• Journal of Korean Academy of Nursing
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• v.33 no.6
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• pp.705-712
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• 2003

Purpose: The purpose of this study was to explore factors that influence care dependency of institutionalized patients with dementia. Method: This study utilized descriptive correlational design. The convenience sample was composed of 110 residents with dementia of two long-term care facilities in Korea. Stepwise multiple regression was used to identify significant factors influencing care dependency in patients with dementia. Care dependency was measured using the Care Dependency Scale, Korean version(CDS-K). Cognition was measured by the MMSE-K. Functional disability was measured by the PULSES Profile. Behavioral dysfunction was measured by the modified E-BEHAVE AD. Result: Care dependency was significantly influenced by cognition, functional disability, behavioral dysfunction, and duration of dementia. This regression model explained 61 % of the variances in care dependency. Cognition explained 37% of the variances, and functional disability explained 21% of the variances. Conclusion: Results of this study suggest that professional caregivers intervene more effectively in caring for their patients with dementia by recognizing the patients cognitive, functional, behavioral disability, and its periodic change. Individually, remaining abilities-focused intervention should be applied to enhance patient to be dependent and to prevent unnecessary independency.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.621-626
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• 2002

A satellite scatterometer is a microwave radar sensor used to measure the backscattering at a sea surface. This instrument transmits radar pulses to the sea surface and measure the radar energy reflected back towards the source. Changes in wind velocity make sea surface roughness change and then affect on backscattered power. This gives us information of sea surface wind speed. Directions of wind vectors are acquired by multiple, collocated, and nearly simultaneous measurements. It should be noted that the scatterometer observes not the wind directly but the wind stress vector relative to the surface current. This suggests the possibility that the satellite scatterometer winds can include the effect of the surface current. This study shows the evidence that scatterometer measure surface wind stress, not surface winds and presents the velocity structure of oceanic warm and cold eddies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1186-1189
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• 2004

A new pump used in arthroscopy surgery was developed. The pump is driven by pneumatic air compressor and controlled by a stepper motor connected to an air regulator. Pressure control performance was observed to be similar compared to commercially available artheroscopy pumps. However, pressure pulses observed in the commercial pumps driven by multiple rollers disappeared in the pneumatically driven pump. The new pump required containers to enclose and squeeze saline solution packs. A dramatic saving in manufacture cost is expected considering the simple pneumatic drive used in this pump.

• Journal of the Korean Magnetic Resonance Society
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• v.12 no.2
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• pp.111-118
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• 2008

The mechanism of charge flow has been probed by measuring the $^{1}H$ chemical shift on a proton-irradiated ${KH_2}{PO_4}$ (KDP) single crystal. The proton irradiation caused the increase in $^{1}H$ chemical shift. It can be interpreted as the electronic charge transfer from the proton to oxygen atom, accompanied with the proton displacement along the hydrogen bond. For the high resolution $^{1}H$ chemical shift measurement, CRAMPS (Combined Rotation And Multiple Pulses) technique is utilized.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1504-1512
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• 2016

This paper presents a new single-phase asymmetrical cascaded multilevel DC-link inverter. The proposed inverter comprises two stages. The main stage of the inverter consists of multiple similar cells, each of which is a half-bridge inverter consisting of two switches and a single DC source. All cells are connected in a cascaded manner with a fixed neutral point. The DC source values are not made equal to increase the performance of the inverter. The second circuit is a folded cascaded H-bridge circuit operating at a line frequency. One of the main advantages of this proposed topology is that it is a modular type and can thus be extended to high stages without changing the configuration of the main stage circuit. Two control schemes, namely, low switching with selective harmonic elimination and sinusoidal pulse width modulation, are employed to validate the proposed topology. The detailed approach of each control scheme and switching pulses are discussed in detail. A 150W prototype of the proposed system is implemented in the laboratory to verify the validity of the proposed topology.