• Korean journal of communication and information
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• v.22
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• pp.131-166
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• 2003

The opening of advertising market and introduction of the free competition doctrine make the competition harsher among advertising agencies. Advertising agencies do their best to execute their ad more efficiently and scientifically. But, it is the reality that broadcasting advertising industry in korea did not construct enough infrastructure to execute the systematic activities compared with that of advanced countries. So, we need to grasp the present conditions and draw a time-table to construct primarily necessary infrastructures. In case of hardware infrastructure in advertising industry, digitalization of broadcasting and convergence of broadcasting with telecommunication make it hurry to construct that. But as the ad agencies was in the situation to compete each other, they have a difficulty to construct common hardware infrastructure enthusiastically. Thus, it is necessary to build hardware infrastructure in advertising industry for policy. And the construction of that should be executed systematically not for the short term effects but for the long term objectives. Also, it is the most important to construct reliable Software infrastructure in advertising industry from all of ad agencies. In these days, ad agencies have a tendency not to believe the important information, like the data of ratings and advertising transaction information, in relation to the advertising activities. And they do not share and communicate about the information of the advertising industry trends, research trends, advertisement related information. So, it is also hurry to build the on-line and off-line database system. Finally, for the development of brainware infrastructure in advertising industry, it is the most necessary to activate the cooperation relation between university and advertising agencies. Universities need to invite experts in the advertising to teach the students practical knowledge and ad agencies to recruit students who want to develop their carrier in the advertising industries. In conclusion, advertising industry in korea to solve these tasks for the development of advertising industry infrastructure in the way of cooperation and harmony of each other rationally and efficiently.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.19-24
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• 2020

In this work, the electrical property of Si-doped β-Ga2O3 was investigated via a post-growth annealing process. The Ga2O3 samples were annealed under air (O-rich) or N2 (O-deficient) ambient at 800~1,200℃ for 30 mins. There was no correlation between the crystalline quality and the electrical conductivity of the films within the experimental conditions explored in this work. However, it was observed the air ambient led to severe degradation of the film's electrical conductivity while N2-annealed samples exhibited improvement in both the carrier concentration and Hall mobility measured at room temperature. Interestingly, the x-ray photoemission spectroscopy (XPS) revealed that both annealing conditions resulted in higher concentration of oxygen vacancy (VO). Although it was a slight increase for the air-annealed sample, high resistivity of the film strongly suggests that VO cannot be a shallow donor in β-Ga2O3. Therefore, the enhancement of the electrical conductivity of N2-annealed samples must be originated from something other than VO. One possibility is the activation of Si. The XPS analysis of N2-annealed samples showed increasing relative peak area of Si 2p associated with SiOx with increasing annealing temperature from 800 to 1,200℃. However, it was unclear whether or not this SiOx was responsible for the improvement as the electrical conductivity quickly degraded above 1,000℃ even under N2 ambient. Furthermore, XPS suggested the concentration of Si actually increased near the surface as opposed to the shift of the binding energy of Si from its initial chemical state to SiOx state. This study illustrates the electrical changes induced by a post-growth thermal annealing process can be utilized to probe the chemical and electrical states of vacancies and dopants for better understanding of the electrical property of Si-doped β-Ga2O3.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.451-464
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• 2008

Three-phase inverse fluidized bed has been widely adopted with its increasing demand in the fields of bioreactor, fermentation process, wastewater treatment process, absorption and adsorption processes, where the fluidized or suspended particles are small or lower density comparing with that of continuous liquid phase, since the particles are frequently substrate, contacting medium or catalyst carrier. However, there has been little attention on the three-phase inverse fluidized beds even on the hydrodynamics. Needless to say, the information on the hydrodynamics and transport phenomena such as heat and mass transfer in the inverse fluidized beds has been essential for the operation, design and scale-up of various reactors and processes which are employing the three-phase inverse beds. In the present article, thus, the information on the three-phase inverse fluidized beds has been summarized and reorganized to suggest a pre-requisite knowledge for the field work in a sense of engineering point of view. The article is composed of three parts; hydrodynamics, heat and mass transfer characteristics of three-phase inverse fluidized beds. Effects of operating variables on the phase holdup, bubble properties and particle fluctuating frequency and dispersion were discussed in the section of hydrodynamics; effects of operating variables on the heat transfer coefficient and on the heat transfer model were discussed in the section of heat transfer characteristics ; and in the section of mass transfer characteristics, effects of operating variables on the liquid axial dispersion and volumetric liquid phase mass transfer coefficient were examined. In each section, correlations to predict the hydrodynamic characteristics such as minimum fluidization velocity, phase holdup, bubble properties and particle fluctuating frequency and dispersion and heat and mass transfer coefficients were suggested. And finally suggestions have been made for the future study for the application of three-phase inverse fluidized bed in several available fields to meet the increasing demands of this system.

• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.309-318
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• 2002

A stoichiometric mixture of evaporating materials for $CdIn_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CdIn_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CdIn_2S_4$ single crystal thin films measured with Hall effect by van der Pauw method are $9.01{\times}10^{16}\;cm^{-3}$ and $219\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CdIn_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.7116\;eV-(7.74{\times}10^{-4}\;eV)T^2/(T+434)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CdIn_2S_4$ have been estimated to be 0.1291 eV and 0.0248 eV, respectively, by means of the photocurrent spectra and the Hopfield quasi cubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}5$ states of the valence band of the $AgInS_2$/GaAs epilayer. The three photocurrent peaks observed at 10K areascribed to the $A_1$-, $B_1$-, and C1-exciton peaks for n = 1.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.364-370
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• 1994

The purpose of this study is to evaluate the clinical application of the no carrier added $[^{51}Cr]Cr(III)$-EDTA complexes, produced at Korea Cancer Center Hospital. The $[^{51}Cr]Cr(III)$-EDTA complexes, usefut for measurement of GFR were prepared at room temperature in the presence of bicarbonate catalysts. The radiochemical purity of $[^{51}Cr]Cr(III)$-EDTA was over 99% by paper electrophoresis. The time activity curves were obtained by counting the blood samples from 5 volunteers and counting the head and neck regions with whole body counter after injection of the $^{51}Cr$-EDTA, respectively. After the nonlinear regression, the area under curve was obtained. The plasma clearance of the $^{51}Cr$-EDTA was calculated with injected dose/AUC. The clearance rate calculated with the head and neck counting data was in good agreement with the result from the plasma sample radioactivity at 1-3 hrs after injection. From this result, the counting of head and neck region and the nonlinear regression by 2-compartment model could be applied for the measurement of the clearance rate. Using MIRD system, the absorbed radiation dose was calculated by residence $time{\times}S$. The absorbed whole body radiation dose was negligibly small.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.77-88
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• 2000

In this paper, the 3-mode variable gain high power amplifier for a transmitter of INMARSAT-B operating at L-band(1626.5-1646.5 MHz) was developed. This SSPA can amplify 42 dBm in high power mode, 38 dBm in medium power mode and 36 dBm in low power mode for INMARSAT-B. The allowable errol sets +1 dBm as the upper limit and -2 dBm as the lower limit, respectively. To simplify the fabrication process, the whole system is designed by two parts composed of a driving amplifier and a high power amplifier. The HP's MGA-64135 and Motorola's MRF-6401 were used for driving amplifier, and the ERICSSON's PTE-10114 and PTF-10021 for the high power amplifier. The SSPA was fabricated by the RP circuits, the temperature compensation circuits and 3-mode variable gain control circuits and 20 dB parallel coupled-line directional coupler in aluminum housing. In addition, the gain control method was proposed by digital attenuator for 3-mode amplifier. Then il has been experimentally verified that the gain is controlled for single tone signal as well as two tone signals. In this case, the SSPA detects the output power by 20 dB parallel coupled-line directional coupler and phase non-splitter amplifier. The realized SSPA has 41.6 dB, 37.6 dB and 33.2 dB for small signal gain within 20 MHz bandwidth, and the VSWR of input and output port is less than 1.3:1. The minimum value of the 1 dB compression point gets more than 12 dBm for 3-mode variable gain high power amplifier. A typical two tone intermodulation point has 36.5 dBc maximum which is single carrier backed off 3 dB from 1 dB compression point. The maximum output power of 43 dBm was achieved at the 1636.5 MHz. These results reveal a high power of 20 Watt, which was the design target.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.880-886
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• 2007

We have proposed a new "hybrid" envelope elimination and restoration(EER) transmitter architecture using an efficiency optimized power amplifier(PA) and modified bias modulator. The efficiency of the PA at the average drain voltage is very important for the overall transmitter efficiency because the PA operates mostly at the average power region of the modulation signal. Accordingly, the efficiency of the PA has been optimized at the region. Besides, the bias modulator has been accompanied with the emitter follower for the minimization of memory effect. A saturation amplifier, class $F^{-1}$ is built using a 5-W PEP LDMOSFET for forward-link single-carrier wideband code-division multiple-access(WCDMA) at 1-GHz. For the interlock experiment, the bias modulator has been built with the efficiency of 64.16% and peak output voltage of 31.8 V. The transmitter with the proposed PA and bias modulator has been achieved an efficiency of 44.19%, an improvement of 8.11%. Besides, the output power is enhanced to 32.33 dBm due to the class F operation and the PAE is 38.28% with ACLRs of -35.9 dBc at 5-MHz offset. These results show that the proposed architecture is a very good candidate for the linear and efficient high power transmitter.

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.107-123
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• 2020

With stabilization of the recent multi-GNSS infrastructure, and as multi-GNSS has been proven to be effective in improving the accuracy of the positioning performance in various industrial sectors. In this study, in view that SF(Single frequency) GNSS receivers are widely used due to the low costs, evaluate effectiveness of SF Real Time Point Positioning(SF-RT-PP) based on four multi-GNSS surveying methods with RTCM-SSR correction streams in static and kinematic modes, and also derive response challenges. Results of applying SSR correction streams, CNES presented good results compared to other SSR streams in 2D coordinate. Looking at the results of the SF-RT-PP surveying using SF signals from multi-GNSS, were able to identify the common cause of large deviations in the altitude components, as well as confirm the importance of signal bias correction according to combinations of different types of satellite signals and ionospheric delay compensation algorithm using undifferenced and uncombined observations. In addition, confirmed that the improvement of the infrastructure of Multi-GNSS allows SF-RT-SPP surveying with only one of the four GNSS satellites. In particular, in the case of code-based SF-RT-SPP measurements using SF signals from GPS satellites only, the difference in the application effect between broadcast ephemeris and SSR correction for satellite orbits/clocks was small, but in the case of ionospheric delay compensation, the use of SBAS correction information provided more than twice the accuracy compared to result of the Klobuchar model. With GPS and GLONASS, both the BDS and GALILEO constellations will be fully deployed in the end of 2020, and the greater benefits from the multi-GNSS integration can be expected. Specially, If RT-ionospheric correction services reflecting regional characteristics and SSR correction information reflecting atmospheric characteristics are carried out in real-time, expected that the utilization of SF-RT-PPP survey technology by multi-GNSS and various demands will be created in various industrial sectors.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.345-358
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• 2021

This study focuses on the development of the liquid air production process that uses LNG (liquefied natural gas) cold energy which usually wasted during the regasification stage. The liquid air can be transported to the LNG exporter, and it can be utilized as the cold source to replace certain amount of refrigerant for the natural gas liquefaction. Therefore, the condition of the liquid air has to satisfy the available pressure of LNG storage tank. To satisfy pressure constraint of the membrane type LNG tank, proposed process is designed to produce liquid air at 1.3bar. In proposed process, the air is precooled by heat exchange with LNG and subcooled by nitrogen refrigeration cycle. When the amount of transported liquid air is as large as the capacity of the LNG carrier, it could be economical in terms of the transportation cost. In addition, larger liquid air can give more cold energy that can be used in natural gas liquefaction plant. To analyze the effect of the liquid air production amount, under the same LNG supply condition, the proposed process is simulated under 3 different air flow rate: 0.50 kg/s, 0.75 kg/s, 1.00 kg/s, correspond to Case1, Case2, and Case3, respectively. Each case was analyzed thermodynamically and economically. It shows a tendency that the more liquid air production, the more energy demanded per same mass of product as Case3 is 0.18kWh higher than Base case. In consequence the production cost per 1 kg liquid air in Case3 was $0.0172 higher. However, as liquid air production increases, the transportation cost per 1 kg liquid air has reduced by $0.0395. In terms of overall cost, Case 3 confirmed that liquid air can be produced and transported with $0.0223 less per kilogram than Base case.

• Korean Journal of Biological Psychiatry
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• v.15 no.2
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• pp.83-91
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• 2008

Objectives : Neurological soft signs have been regarded as endophenotypes associated with the genetic basis of schizophrenia. This study was to investigate the intra-familial correlations of the neurological soft signs according to their genetic loading. Methods : Schizophrenic patients(N=14) were included, who had one parent with a family history of schizophrenia and the other without it. Genetic loading was determined by the patient's family history of schizophrenia using the Family Interview for Genetic Studies(FIGS). These parents were subdivided into two groups. The first group was designated as 'presumed carriers'(N=9) of genetic loading, who had one or more schizophreic firstor second-degree relatives. The second group was designated as 'presumed non-carriers'(N=11) of genetic loading, who had no schizophrenic first- or second-degree relatives. Normal controls(N=12) consisted of people without schizophrenic relatives. NSS were evaluated using the Neurological Evaluation Scale-Korean Version (NES-K), and the intra-familial correlations of NSS were tested using the Intra-Class Coefficients(ICC) method. Results : The scores of Motor Coordination subdimension of NES-K were significantly correlated between the patients and their presumed carriers(ICC=.804, p=.016), but not significantly correlated between the patients and their presumed noncarriers. In other subdimensions of NES-K, no significant correlation were found between the patients and their parents regardless of the genetic loading. But, there were no statistically significant differences in the scores of Motor Coordination subdimension of NES-K between the patients and controls. Conclusion : This study did not prove that the neurological soft signs might be an endophenotype of schizophrenia that cosegregate with the genetic loading. The future study using more subjects than this would be needed.