• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4147-4152
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• 2011

Compared to the constant modulus algorithm (CMA), the modified CMA (MCMA) is easy not only to improve the steady-state performance but also to be expanded to higher-order constellations by using fewer moduli with evenly spaced. In this paper, it is shown that the MCMA is sufficient to achieve satisfactory steady-state performance by applying a variable step-size to the MCMA without switching to an hard decision-directed algorithm. Two new methods varying the step-size are proposed, and the performance improvement of the MCMA with the new methods of variable step-size is presented as compared to the CMA and the fixed step-size MCMA through computer simulations.

• Journal of Magnetics
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• v.18 no.3
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• pp.240-244
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• 2013

The influences of Gallium doping on the magnetic microstructures and corrosion behaviors of Nd-Fe-B-Ti-C alloys are investigated. The cooling rate for obtaining fully amorphous structure is raised, and the glassforming ability is improved by the Ga addition. The High Resolution Transmission Electron Microscopy image shows that the ${\alpha}$-Fe and $Fe_3B$ soft magnetic phases become granular surrounded by the $Nd_2Fe_{14}B$ hard magnetic phase. The rms and $({\Delta}{\varphi})_{rms}$ value of Nd-Fe-B-Ti-C nanocomposite alloy thick ribbons in the typical topographic and magnetic force images detected by Magnetic Force Microscopy(MFM) decreases with 0.5 at% Ga addition. The corrosion resistances of $Nd_9Fe_{73}B_{12.6}C_{1.4}Ti_{4-x}Ga_x$ (x = 0, 0.5, 1) alloys are enhanced by the Ga addition. It can be attributed to the formation of more amorphous phases in the Ga doped samples.

• The Korean Journal of Archival Studies
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• no.2
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• pp.49-76
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• 2000

The government is pushing hard to realize the electronic and knowledge government. In connection with the efforts most public institutions have already started adopting the electronic document management system(EDMS), and have entered in a phase of modification of, and supplement to the system for the flow of the electronic documents among the agencies to be made possible by the month of November this year. The present situation is that the modification and supplement of EDMS are underway in the field that is unrelated to the records and archival management, what has been foreseen in the academic world of archival science. Under this circumstances the article places emphasis on the importance of the positive participation of the archivists in the development of the EDMS. To be concrete it reveals how the archival achievements can be practically applicable to the EDMS. What is particularly conspicuous in the article is the detailed description of how usefully control of record production, classification and description, evaluation and selection that are put into practice in the archival management law can be embodied in the development of the EDMS. Finally the article put emphasis on the positive exchanges and integration to bring the archival management science and computer science, archival management law and electronic government law, the archival management agencies and the agencies in charge of the electronic government together into whole to find a way for the methodical achievements of scientific archival management to be positively applicable to the electronic document management system(EDMS).

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.604-615
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• 2019

Single-user spectrum sensing is susceptible to multipath effects, shadow effects, hidden terminals and other unfavorable factors, leading to misjudgment of perceived results. In order to increase the detection accuracy and reduce spectrum sensing cost, we propose an adaptive cooperative sensing strategy based on an estimated signal-to-noise ratio (SNR). Which can adaptive select different sensing strategy during the local sensing phase. When the estimated SNR is higher than the selection threshold, adaptive double threshold energy detector (ED) is implemented, otherwise cyclostationary feature detector is performed. Due to the fact that only a better sensing strategy is implemented in a period, the detection accuracy is improved under the condition of low SNR with low complexity. The local sensing node transmits the perceived results through the control channel to the fusion center (FC), and uses voting rule to make the hard decision. Thus the transmission bandwidth is effectively saved. Simulation results show that the proposed scheme can effectively improve the system detection probability, shorten the average sensing time, and has better robustness without largely increasing the costs of sensing system.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.439-443
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• 2018

The outstanding characteristics of high quality GaN single crystal substrates make it possible to apply the manufacture of high brightness light emitting diodes and power devices. However, it is very difficult to obtain high quality GaN substrate because the process conditions are hard to control. In order to effectively control the formation of GaN polycrystals during the bulk GaN single crystal growth by the HVPE (hydride vapor phase epitaxy) method, a quartz ring was introduced in the edge of substrate. A variety of evaluating method such as high resolution X-ray diffraction, Raman spectroscopy and photoluminescence was used in order to measure the effectiveness of the quartz ring. A secondary ion mass spectroscopy was also used for evaluating the variations of impurity concentration in the resulting GaN single crystal. Through the detailed investigations, we could confirm that the introduction of a quartz ring during the GaN single crystal growth process using HVPE is a very effective strategy to obtain a high quality GaN single crystal.

• The Korean Journal of Legal Medicine
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• v.42 no.4
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• pp.126-140
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• 2018

The diagnosis of cause of death (COD) or estimation of postmortem interval (PMI) is hard to perform using postmortem blood or other bodily fluids due to various biochemical changes that occur during the agonal phase or after death. To solve these problems, new paradigms and new analytical methods are needed. In this study, postmortem blood was fractionated with specific gravity 1.021, 1.029, 1.038, and 1.045, and the absorbance patterns of each sample of the 131 total cases (12 kinds of COD) were analyzed using a spectrometer. The absorbance was grouped into 9 patterns (ABS pattern 1 to 9) according to the wave length and the signal intensity. These patterns of postmortem blood were found to be distinctly different from the absorbance pattern of fresh blood. The analysis of ABS patterns is useful for the diagnosis of deaths due to acute or rapid bleeding, fire death, drowning and, in some cases, poisoning, but is not useful for the estimation of PMI.

• Journal of Internet Computing and Services
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• v.24 no.5
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• pp.37-50
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• 2023

In general, PLL or DDS are mainly used as precise and stable frequency synthesis methods. For stable operation, a PWM frequency generation algorithm was designed and implemented using FPGA. This is an algorithm that creates a frequency 8,192 times the target frequency and then performs the D flip-flop 13 times to generate multiple frequencies with a precision of 1 Hz. Using the designed algorithm, it is applied to the Berthing system for stopping trains in station. The applied product was developed and tested against the existing operating system to confirm its superior performance in terms of frequency generation accuracy.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.58-65
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• 2011

Construction Productivity is one of the most important elements in construction management. It is used in construction process scheduling and cost management, which are significant sector in construction management. It is important to make appropriate schedule and monitor how works are done within schedule. But construction project contains uncertainty and inexactitude, modifying construction schedule is being an issue to manage construction works well. Even though prediction and monitoring of productivity can be principal activity, it is hard to predict productivity with manager's experience and a standard of estimate. A large number of factors influencing productivity, such as drawing, construction method, weather, labor, material, equipment, etc. But current calculation of productivity depends on empirical probability, not consider difference of each influencing factor. In this research, the aim is to present a productivity predicting regression model of form work, which includes effectiveness of influences factors. 5 variables existed inside form work are selected by interview and site research based on literature review of existed various productivity influencing factors. The effectiveness and correlation of productivity influencing factors are analyzed by statistical approach, and it is used to make productivity regression model. The finding of this research will improves monitoring and controlling of project schedule in construction phase.

• International Journal of Computer Science & Network Security
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• v.24 no.3
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• pp.151-159
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• 2024

Twin clutch model enables the power-shifts as conventional planetary automatic transmission and eradicates the disadvantages of single clutch trans- mission. The automatic control of the dual clutches is a problem. Particularly to control the clutching component that engages when running in one direction of revolution and disengages when running the other direction, which exchange the torque smoothly during torque phase of the gearshifts on planetary-type automatic transmissions, seemed for quite a while hard to compensate through clutch control. Another problem is to skip gears during multiple gearshifts. However, the twin clutch gear control described in ["M Goetz, M C Levesley and D A Crolla. Dynamics and control of gearshifts on twin clutch transmissions, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2005"], a significant improvement in twin clutch gear control system is discussed. In this research our objective is to formally specify the twin clutch gear control system and verify it with the help of formal methods. Formal methods have a high potential to give correctness estimating techniques. We use UPPAAL for formal specification and verification. Our results show that the twin clutch gear control model partially fulfills its functional requirements.

• Journal of Korean Academy of Nursing
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• v.26 no.2
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• pp.483-496
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• 1996

The purpose of this study was to describe how Korean nurses overcome the language barrier while working in the U.S. hospital settings. Twelve Korean nurses living in New York metropolitan area were asked open-ended, descriptive questions to collect the data. The interviews were done in Korean. All interviews were audiotaped under the permission of the participants and were transcribed verbatim. The data were analyzed using grounded theory analysis. The research process consisted of two phases. In the first phase 8 Korean nurses were interviewed and analyzed. In the second phase, further data were collected to verify categories and working hypotheses that were emerged from the first phase. The results of this study show that all Korean nurses experienced severe psychological stress such as confusion, anxiety, frustration, loss of self-confidence, embarrassment, guilt, depression, anger, and fear. Among the mode of communication such as listening, speaking, leading, and writing, they had the most difficulty in speaking. Speaking ability was especially important for them because of the emphasis of individualism and self-defense in the U.S. Among the verbal communication modes, non-face-to-face communications such as phone conversation and body language were the most difficu1t for them to overcome. It took at least 2 years for the participants to initially overcome the language barrier in U.S. hospitals. After 2-5 years they began to feel comfortable even in non-face-to-face communication. They could actively search for the better place to work after 5 years. They finally felt comfortable in English and in their job almost after 10 years. The factors that influenced the English improvement were ‘the years of clinical experience in Korea’, ‘the decade they came to the U.S.’ ‘coming to U.S. alone or with other Korean nurses’, ‘racial homogeneity or heterogeneity of the working unit’, and ‘the degree of social support’. The strategies Korean nurses used to overcome the language barrier included depending on the written communication, using ‘nunchi’, working and studying hard, and establishing good interpersonal relationships with co-workers. They also employed assertive behavior of the U.S., such as using more explicit verbal language and employing smiles and eye contact with others during the conversation. The results of the study may help Korean nurses and nursing students who try to work in U.S. hospital settings by understanding problems other Korean nurses faced, factors that influenced their English improvement, and strategies they used. They may also help U.S. nurses and administrators in developing and implementing efficient programs for newly employed Korean nurses by understanding major problems and feelings the Korean nurses experienced and strategies they used to overcome the language barriers.