• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.27-33
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• 2004

In this paper, we present a carrier recovery circuit using the polarity-decision algorithm that recovers a phase and a frequency error simultaneously. The proposed algorithm catches a frequency error based on a differential of an angular velocity of the signal constellations. Using the differential of a phase error may compensate the frequency error. The symbol prediction method in the proposed algorithm accumulates the symbols, which makes easy to calculate a phase differential. The hardware size of the algerian is small since we use Q data or I only to get phase information. As a result, the algerian shows a pull-in range of normalized frequency error 0.5 under AWGN 15dB.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.575-590
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• 2017

PolyHIPEs membrane prepared with styrene (St), divinylbenzene (DVB), and ethylhexyl acrylate (EHA) can yield a unique pore structure provided by large voids highly interconnected by many small window throats. With the advantageous pore structure, PolyHIPE presents a potential as a support for carrier facilitated transport membrane. Tricaprylmethylammonium chloride (Aliquat 336) can be efficiently incorporated into the PolyHIPE membrane by a two-step solvent-nonsolvent method to obtain an Aliquat 336-immobilized PolyHIPE membrane with good stability. The study of Cr (VI) transport through Aliquat 336-immobilized PolyHIPE membrane indicates that the membrane has high initial flux and maxima stripping flux ($J_f^o=15.01({\mu}mol/m^2s)$, $J_s^{max}=6.15({\mu}mol/m^2s)$). The reusability study shows that the Aliquat 336-immobilized PolyHIPE membrane can maintain high Cr(VI) recovery efficiency even after 15 cycles of operations. The developed membrane was also used in the separation of Cr (VI) from other anions (i.e., $SO_4{^{2-}}$ and $NO_3{^-}$) and other cations (i.e., Ni (II), Mg (II) and Cu (II)) with good selectivity.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.22-31
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• 2006

When ironwork, especially steel roll coil, is transported to customers, land transportation and sea transportation are usually used. To transport steel roll coil fast and safe without damaging it, it is necessary that the steel roll coil has to be in stable condition. These days, apitong, which is all imported from overseas, is being used to support the steel roll coil, but because of apitong's rigidity, it damages the coil and when the coil is damaged, it is hard to fix. Due to the fact that recovering damage of the coil is almost impossible, we have to find the new type of dunnage that can substitute the apitong. In this paper, the arrays and the kinds of reinforcements, and rectangular type and trapezoid of dunnage will be talked about. The phenomenon of rolling and the impact when the carrier start moving and stop will be talked about as well. Therefore, we are going to develop a dunnage that does not damage ironwork and has better recovery and softness than existing apitong dunnage.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.229.1-229.1
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• 2014

Tactile sensors have widely been researched in the areas of electronics, robotic system and medical tools for extending to the form of bio inspired devices that generate feeling of touch mimicking those of humans. Recent efforts in adapting the tactile sensor have included the use of novel materials with both scalability and high sensitivity [1]. Graphene, a 2-D allotrope of carbon, is a prospective candidate for sensor technology, having strong mechanical properties [2] and flexibility, including recovery from mechanical stress. In addition, its truly 2-D nature allows the formation of continuous films that are intrinsically useful for realizing sensing functions. However, very few investigations have been carrier out to investigate sensing characteristics as a device form with the graphene subjected to strain/stress and pressure effects. In this study, we present a sensor of vertical forces based on single-layer graphene, with a working range that corresponds to the pressure of a gentle touch that can be perceived by humans. In spite of the low gauge factor that arises from the intrinsic electromechanical character of single-layer graphene, we achieve a resistance variation of about 30% in response to an applied vertical pressure of 5 kPa by introducing a pressure-amplifying structure in the sensor. In addition, we demonstrate a method to enhance the sensitivity of the sensor by applying resistive single-layer graphene.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1536-1547
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• 1994

This paper presented the implementation and design of narrowband wireless MODEM for packet transmission. The MODEM consists of transmitter, receiver, and the control unit. The BPSK modulation with narrowband filtering is used. The receiver consists of functional modules such as carrier recovery, bit synchronization, lock detector, etc. We evaluated the performance of packet transmission with three MODEM sets implemented in distributed packet radio network. We confirmed the transmission of packetized data through RS232C port of PC. Also, we presented results of experimental data by using measuring instruments. The implemented MODEM in this paper is expected to be useful for the design of wireless LAN system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.364-370
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• 2006

It is required for correct signal detection to accurately maintain the synchronization of frequency and timing in a TDMA system. In this paper, we consider nondecision-aided estimation of frequency offset for the transmission of QPSK signal in a TDMA-based satellite system. The proposed scheme estimates the phases of two parts in the burst and then estimates the frequency offset based on the difference between the two estimated phases. Thus, it can provides performance comparable to that of conventional schemes, while significantly reducing the implementation complexity, The performance of the proposed scheme is analyzed and verified by computer simulation, when applied to a GSM based geostationary earth orbit mobile radio(GMR) system.

• Pediatric Infection and Vaccine
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• v.2 no.2
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• pp.180-185
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• 1995

1. Purpose The accurate diagnosis and proper treatment of group A streptococcus should be emphasized concerning about possible development of late sequelae, such as acute rheumatic fever and acute glomerulonephritis. We would like to know the recover rate of beta-hemolytic streptococci by throat swab culture at the in-patient 2. Methods The throat swab cultures and filled up flow-sheets were undertaken on 619 children who had admitted to hospital, KyungHee university hospital from may 1994 to april 1995 prospectively. At the same time on admission, throat culture was performed. 3. Results The highest recover rate of BHS(Beta-Hemolytic Streptococci)and GAS(Group A Streptococci) were seen in above 10 years old, as 9.1% and 1.9%. BHS were obtained in 39 cases(6.3%) among 619 children while GAS was obtained in 3 cases (0.4%). Among 39 specimens of BHS, 33 specimens were classified as non-grouping streptococcus. 4. Conclusion The poor recovery rate of GAS inpatient compared with normal carrier rate is likely due to possible antibiotic abuse, errors in processing samples, and epidemiologic factors such as seasons and geographic areas. It is necessary to evaluate the clinical significance of non-A,B,C,G streptococcal infections and carriers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.737-746
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• 1996

In this paper, we present simulation result of quantization effects about a new Angular From Carrier Recovery Loop(AF CR loop) for PSK modulation technique. AF CR loop includes detected angle symbol and Multi Level hardimiter. In general, detected angle is used in dtermining symbol. Because detected angle is used to make an error signal of phase detector output, hardware implementation of AF CR loop is simpler than that of other loops. Before hardware implementation of AF CR loop, the result due to quantization effect should be investigated. In order to confirm quntization effect of AF CR loop, we evaluate performance of this loop by Monte-Carlosimulation method. Under both in the AWGN and Jake's fading noise channel environments, we confirmed the characteristics of AF CR loop in terms of RMS jitter due to quntization effect. Differential APSK modulation schemeis used in this paper. Especially, Jake's fading channel is used as a channel model and also AGC(Automatic Gain Control) is used in the overall process of performance evaluation. We obtained the resonable result of quantization effect about AF CR loop. With the result of performanceevaluation based on quantization effects, we can expect to operate AF CRloop under the fading channel environments reasonably well.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.953-956
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• 2009

We have investigated the effect of light on amorphous silicon thin film transistors based photo-sensor applications. We have analyzed the instability caused by electrical gate bias stresses under the light illumination and the effect of photo-induced quasi-annealing on the instability. Threshold voltage ($V_{TH}$) under the negative gate bias stress with light illumination was more decreased than that under the negative gate bias stress without light illumination even though $V_{TH}$ caused by the light-induced stress without negative gate bias was shifted positively. These results are because the increase of carrier density in a channel region caused by the light illumination has the enhanced effect on the instability caused by negative gate bias stress. The prolonged light illumination led to the recovery of shifted VTH caused by negative gate bias stress under the light illumination due to the recombination of trapped hole charges.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7A
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• pp.725-733
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• 2006

In this paper, we propose an algorithm which makes the frequency of output signal synchronize with frequency of input signal in Equalization Digital On-channel Repeater (EDOCR) system which was proposed to overcome the disadvantage of conventional Digital On-Channel Repeater (DOCR). Also, we verify the algorithm by using the mathematical equivalent model and analysis the performance by implying the algorithm to EDOCR. The main idea is to use the frequency offset information, which comes from carrier recovery in the receiving part of EDOCR, when the demodulated symbol is re-modulated in transmitting part. Based on the proposed algorithm, EDOCR not only makes the output signal synchronized with input signal in frequency but also emit the output signal which satisfies the ATSC transmission standard without additional equipments such as Global Positioning System (GSP).