• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.179-182
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• 1998

Carrier recovery, the process of recoverying the carrier in receiver, removes the phase difference between VCO and the received signal. However, the conventional structure of carrier recovery cannot be applied to multi-level QAM demodulator because of the increasing decision interval and the complexity of control as the number of symbol increases. In this paper, we suggest a new carrier recovery algorithm using $\theta-matching$ algorithm for multi-level QAM demodulation to overcome this problem and analysis the performance and implement it.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.432-435
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• 1996

The performance of one-column isothermal PSA process is assessed by dynamic simulator, gPROMS. The four-step and five-step processes are compared. A five-step process is employed in order to show the effect of the addtional cocurrent depressurization step on the four-step PSA process. Two processes parameters, purity and recovery of SO$_{2}$ are used for the performance comparison. The results of dynamic simulation show that four-step process is superior to five-step process in recovery, but not in purity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1618-1637
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• 2018

By means of compressive sensing (CS) technique, this paper considers the collection of sensor data with spatiotemporal correlations in wireless sensor networks (WSNs). In energy-constrained WSNs, one-dimensional CS methods need a lot of data transmissions since they are less applicable in fully exploiting the spatiotemporal correlations, while the Kronecker CS (KCS) methods suffer performance degradations when the signal dimension increases. In this paper, an appropriate sensing matrix as well as an efficient sensing method is proposed to further reduce the data transmissions without the loss of the recovery performance. Different matrices for the temporal signal of each sensor node are separately designed. The corresponding energy-efficient data gathering method is presented, which only transmitting a subset of sensor readings to recover data of the entire WSN. Theoretical analysis indicates that the sensing structure could have the relatively small mutual coherence according to the selection of matrix. Compared with the existing spatiotemporal CS (CS-ST) method, the simulation results show that the proposed efficient measurement method could reduce data transmissions by about 25% with the similar recovery performance. In addition, compared with the conventional KCS method, for 95% successful recovery, the proposed sensing structure could improve the recovery performance by about 20%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.9
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• pp.627-632
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• 2011

As an innovative effort to secure economically viable heat recovery system, various fin shapes for industrial fin-tube heat exchangers have been studied for better performance. In this study, the waste gas heat recovery from four different fin shapes was experimentally performed for heat transfer rate and pressure drop. According to the tested results, the twist and wavy shape fins of rectangular type show the superior performance in terms of Goodness factor and jH/f factor ratio, whereas the circular spiral fin shows the inferior values. Experimental results shows good comparison with the numerical results with a slight discrepancy of 5%, which is quite resonable.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.8
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• pp.646-655
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• 2012

This study is intended to analyze the thermal performance and evaluate the applicability about non-duct type heat recovery ventilation system integrated with window. Eventually, economic analysis of the system is conducted according to building energy saving ratio of it. As results of the thermal performance, the U-factor of the window conducted on the basis of KS F 2278 appears to $1.8W/m^2K$, and the effective heat exchange efficiency of the ventilator conducted on the basis of KS B 6879 appears 49.95% for cooling, 66.89% for heating. In the applicability evaluated by TRNSYS 16, the caes of applying the heat recovery ventilator integrated with window is found to reduce the cooling or heating load by 2.9% or 13.5% than the non-ventilator case. The results of economic analysis taking a side of consumer is verified as the payback is 3 years, and the accumulated earning is 1,408,133 won in terms of '600,000 won/unit' for initial cost, 10 years for useful life of the system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1820-1832
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• 1996

The performance of a carrier recovery is severely degraded because of amplitude fluctuations and random phases of the received signai caused by multipath fading in mobile radio channel. In this paper, we present two kinds of carrier recovery technique using pilot tone such as TCT(Tone Calibration Technique) and DTCT(Dual Tone Calibration Technique) and analyze these performance both in Rayleigh and Rician fadings. we also evaluate the BER performance of two carrier recovery systems in terms of design parameters such as pilot-to-singnal power ratio, and detection filter-to-pilot filter bandwidth ratio.

• Physical Therapy Korea
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• v.18 no.1
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• pp.93-103
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• 2011

This study was implemented to verify the feasibility of motor function recovery and the appropriate period for therapy. The research began with spinal laminectomy of 40 white rats of Sprague-Dawley breed and induced them spinal crush injury. Following results were obtained by using the modified Tarlov test (MTT), Basso, Beattle, Bresnahan locomotor rating scale (EBB scale) and modified inclined plate test (MIPT). First, the measurement using the MTT confirm that the most severe aggravation and degeneration of functions are observed two days after induced injury, and no sign of neuromotor function recovery. Second, better scores were achieved by open-ground movement group on BBB locomotor rating scale test, and weight-bearing on inclined plate group show better performance on MIPT. Third, both BBB and MIPT scale manifested the peak of motor function recovery during 16th day after the injury and turn into gradual recovery gradient during 16th to 24th. Fourth, the control group showed functional recovery, however, the level of recovery was less significant when compared with group open-ground movement group and weight-bearing on inclined plate group. Hence, it was clearly manifested that the lumbar region of the spinal cord had shown the best performance when its functions were measured after the execution of specific physical training; therefore it indicated the possibility of learning specific task even in damaged lumbar regions. Thus it is expected to come out with better and more effective functional recovery if concentrated physical therapy was applied starting 4 days after the injury till 16 days, which is the period of the most active recovery.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.103-108
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• 2005

For the development of a disk type oil skimmer for a tank lorry, a basic study on comparison of oil recovery performance between disk materials of oil skimmer was conducted. The experiment results are summarized as follows: In all the disks, the volume of recovery of bunker-A oil was greater than diesel oil. In light oil, there was nearly no differences in the volume of oil recovery by disk material, but in the case of bunker A oil, recovery efficiency showed big differences depending on the disk materials. For diesel oil, the differences in the volume of oil recovery per unit of operation time from the initial time zone were hardly shown. However, the volume of recovery of bunker-A oil linearly increased from the initial operation time in all the disks and the increase showed a slew moving trend as time. went on; therefore, the volume of oil recovery per unit of operation time showed differences depending on time. This result shows that oil viscosity has an effect on the disk recovery efficiency. When comparing the mass of pure oil recovery and the volume of water recovery in the total mass of recovery by bunker-A oil, there was no difference in the volume of oil recovery between the window-aluminum material disk and the disks consisting of other materials, but the volume of water recovery of the former was relatively very small This shows the most ideal result in view of oil recovery efficiency that considers the volume of water recovery. In conclusion, it was found that aluminum is the most advantageous as the material for tank lorry oil skimmer disk.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2081-2093
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• 1994

In this study, we design and implement 64 QAM demodulator which has 155 Mbps, first level of CCITT G707 SDH(Synchronous Digital Hierachy) for STM 1 signal transmission. Carrier recovery which effects the demodulator performance uses decision feedback carrier using 8 bits A/D converter. Also, PSF(Pulse Shaping Filter) is 7 order elliptic filter. Carrier recovery circuit is designed and implemented digital type which use high 3 bits of 8 bits conversion data as data and the order low bits as error data and hybrid type which use VCO and analog integrator. Therefore we obtain stable performance recovery.

• Korean Journal of Materials Research
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• v.26 no.9
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• pp.498-503
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• 2016

The characteristics of aqueous lithium recovery by ion exchange were studied using three commercial cation exchange resins: CMP28 (porous type strong acid exchange resin), SCR-B (gel type strong acid exchange resin) and WK60L (porous type weak acid exchange resin). CMP28 was the most effective material for aqueous lithium recovery; its performance was even enhanced by modifying the cation with $K^+$. A comparison to $Na^+$ and $H^+$ form resins demonstrated that the performance enhancement is reciprocally related to the electronegativity of the cation form. Further kinetic and equilibrium isotherm studies with the $K^+$ form CMP28 showed that aqueous lithium recovery by ion exchange was well fitted with the pseudo-second-order rate equation and the Langmuir isotherm. The maximum ion exchange capacity of aqueous lithium recovery was found to be 14.28 mg/g and the optimal pH was in the region of 4-10.