• Journal of Advanced Navigation Technology
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• v.6 no.4
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• pp.318-325
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• 2002

In this paper, the effects of the interference environments on the performance of the time hopping(TH) binary PPM impulse radio(IR) system are presented. Based on the monocycle pulse available within the frequency of 3.1~10.6 GHz permitted for application by FCC, a PPM-modulated TH IR system simulator was designed and followed by the analysis of the monocycle pulse characteristics as well as the system performance. Particularly for the evaluation of the system performance, the multiple access interference and the narrowband system interference signals were considered as the interference signals. Since the narrowband system interference signal has very narrow bandwidth and very large amplitude compared with those of IR system, the analysis of the IR system performance was implemented by considering the interference power and band fraction ratio of the narrowband interference signal.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.7
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• pp.1032-1037
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• 2002

In this paper, derived monocycle pulse that application is possible within permission frequency band (3.1 ~ 10.6GHz) that establish in FCC. Also, PPM modulated TH IR system simulator is designed in AWGN environment. It is analyzed monocycle pulse specific property and system performance using simulator. Also, analyzed BER performances of IR system in multiple access interference environment using proposed parameters. According to result, application of possible pulse duration$(t_n)$ is very limited by 0.04~0.0326 ns in permission frequency range that establish in FCC. In the case of same pulse signal power, we could know that system performance changes by $N_s$ regardless of pulse duration. IR system that need high speed transmission more than 50 Mbps in multiple access interference environment could know that very serious performance decrease by multiple access Interference happens.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.179-184
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• 2010

In this paper, we analyze and simulate the performance of RAKE receiver for ultra wide band (UWB) systems in indoor multipath radio channel. Pulse position modulation-time hopping (PPM-TH) signal is considered. And we also consider three types of RAKE receivers, which are ideal RAKE, selective RAKE, and partial RAKE receivers. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a.

• Journal of Biosystems Engineering
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• v.17 no.4
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• pp.344-353
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• 1992

This study was carried out to develop a fully-controlled plant growth system for studying the effects of environmental factors on plant growth. The plant growth system consists of the growth chamber, the measurement system for sensing and signal conditioning the environmental factors and the control system which includes control algorithm required for optimum operation and on-line monitoring. The results of the study on the performance of the controlled plant growth system are summarized as follows : 1. Under the light intensity of 18,000~20,000 lux, the temperature was controlled in the range of $22{\pm}0.4^{\circ}C$, the relative humidity of $70{\pm}5%$ respectively. 2. The $CO_2$ concentration was controlled in the range of $1,000{\pm}40ppm$(from 1st to 4th day) and $1,500{\pm}40ppm$(from 4th to 9th day). 3. The electric conductivity(EC) and pH of the nutrient solution were controlled in the range of $1.9{\pm}0.2mS/cm$ and $6.8{\pm}0.5pH$ respectively. 4. Under the above environmental conditions, the average fresh weight of leaf lettuce increased from 10g to 74g in 9 days with 24 hour lighting.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.39-42
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• 2008

In this paper, we analyze the performance of ultra wide band (UWB) systems in indoor wireless channel in accordance with the number of pulses per bit at transmit signals and the decision types of receiver. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a. Two types of UWB signals are considered One is the pulse position modulation-time hopping (PPM-TH) signal. And the other is the pulse amplitude modulation-direct sequence (PAM-DS) signal. It is assumed that the receiver is an ideal receiver which can receive all signals of the multipath.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.429-432
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• 2008

In this paper, performance of a double binary turbo coded ultra wide band (UWB) system is analyzed and simulated in an indoor wireless channel. Binary pulse position modulation-time hopping (BPPM-TH) signals are considered. The indoor wireless channel is modeled as a modified Saleh and Valenzuela (SV) channel. The performance is evaluated in terms of bit error probability (BER). From the simulation results, it is seen that double binary turbo coding offers considerable coding gain with reasonable encoding complexity. It is also demonstrated that the performance of the UWB system can be substantially improved by increasing the number of iterations.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.253-256
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• 2008

In this paper, we analyze the performance of RAKE receiver for impulse radio-ultra wide band (IR-UWB) systems in indoor multipath radio channel. Pulse position modulation-time hopping (PPM-TH) signal is considered. And we also consider three types of RAKE receivers, which are ideal RAKE, selective RAKE, and partial RAKE receivers. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.135-135
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• 2001

Purpose： To know the differences of the proton MR spectroscopic features of the liver between th patients with graft-versus-host disease (GVHD) and without GVHD (non-GVHD) after to marrow transplantation (BMT), and to evaluate the possibility to discriminate GVHD fro non-GVHD by analysis of the in vivo proton MR spectra. Method： We evaluated the in vivo proton MR spectra from the livers of 37 patients wh underwent BMT. Our series included 14 cases with GVHD and 23 without GVHD in the liver. Nineteen men and 18 women were included in our series. All cases of GVHD and 2 o non-GVHD were confirmed by liver biopsy and remaining of non-GVHD by evaluation clinical follow up. Proton MR spectroscopy (1H-MRS) was performed at 1.5T GE Sign Horizon (GE Medical System, Milwaukee, USA) system using localized proton STEAM sequence and body coil in all cases with subjects were located in supine position. N respiratory interruption was required during the spectroscopic signal acquisition. Paramete using in MRS were： TR = over 3000ms, TE = 30ms, number of scans = 128, voxel size = ($2{\times}2{\times}2$)$cm^3$, and one NEX. We evaluated the spectra with an attention to the differences o patterns of the peaks between GVHD and non-GVHD groups. The ratio of peak area of peaks at 1.6-4.1ppm to lipid (0.9-1.6ppm) [P(1.6-4.1ppm)/P(0.9-1.6ppm)] was calculated in GVHD and non-GVHD group, and compared the results between these groups. We als evaluated the sensitivity and specificity for discriminating GVHD from non-GVHD by anal of 1H-MRS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.311-318
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• 2008

We propose new pulse shapes for FCC-compliant ultra-wideband (UWB) radios. The projections onto convex sets (POCS) technique is used to optimize temporal and spectral shapes of UWB pulses under the constraints of all of the desired UWB signal properties: efficient spectral utilization under the FCC spectral mask, time-limitedness, and good autocorrelation. Simulation results show that for all values of the pulse duration, the new pulse shapes not only meet the FCC spectral mask most efficiently, but also have nearly the same autocorrelation functions. It is also observed that our truncated (i.e., strictly time-limited) pulse shapes outperform the truncated Gaussian monocycle in the BER performance of binary TH-PPM systems for the same pulse durations. The POCS technique provides an effective method for designing UWB pulse shapes in terms of its inherent design flexibility and joint optimization capability.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.