• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1079-1086
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• 2008

In this paper, we propose a Cyclic-Prefix Code Division Multiple Access system that uses Sequences with Good Autocorrelation property(GAS-CP-CDMA) and analyze the uplink signal-to-noise ratio performance of that system. Phase-shifted sequences are used for differentiating users. The signals of the GAS-CP-CDMA system experience no (or very little) interferences from co-cell signals because of the good autocorrelation property, but user signals of adjacent cells may yield interferences. The frequency reuse factor in the ordinary CDMA system is around 0.6 and the interference from adjacent cells is about 40 percent of the total interference in the conventional CDMA system. Our numerical analysis shows that the frequency reuse factor and user capacity versus signal-to-noise ratio of the GAS-CP-CDMA system are improved comparing to the conventional CDMA system. The uplink user capacity of the proposed system can be increased up to about twice of that of the conventional CDMA system.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.12-21
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• 2004

Error control is one of major concerns in many electronic systems. Experience shows that most malfunctions during system operation are caused by transient faults, which often mean abnormal signal delays that may result in violations of circuit element timing constraints. This paper presents a novel CMOS-based concurrent timing error detector that makes a flip-flop to sense and then signal whether its data has been potentially corrupted or not by a setup or hold timing violation. Designed circuit performs a quiescent supply current evaluation to determine timing violation from the input changes in relation to a clock edge. If the input is too close to the clock time, the resulting switching transient current in the detection circuit exceeds a reference threshold at the instant of the clock transition and an error is flagged. The circuit is designed with a $0.25{\mu}m$ standard CMOS technology at a 2.5 V supply voltage. The validity and effectiveness are verified through the HSPICE simulation. The simulation results in this paper shows that designed circuit can be used to detect setup and hold time violations effectively in clocked circuit element.

• Journal of the Korea Institute of Building Construction
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• v.13 no.6
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• pp.619-626
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• 2013

Many pictures are taken at a construction site, but the information of the pictures is not managed in an efficient and systematic manner. For this reason, when a construction worker has scant field experience or knowledge, it is hard to communicate with others efficiently. Therefore, the information of the pictures taken is not fully utilized in any deliberation or conflict among interested parties, facilities maintenance, and construction of another structure, although they were taken for those purposes. This study discusses the need for combining vector-photos with image and 5W and 1H information, and develops a prototype module for creating vector-photos and saving them in a server. The vector-photos taken can be saved to a server in real time, and efficiently managed by a DB system. If a system to link the vector-photos with a BIM model is developed in the future, it is expected that the vector information in the picture can be connected with the property information of an object. As a result, the vector-photos can be utilized in more diverse ways.

• Korean Journal of Child Studies
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• v.36 no.2
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• pp.111-130
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• 2015

The purpose of this study was to conduct a qualitative analysis of mothers' role experiences during their children's transition from early childhood to middle childhood. Eleven mothers of first-grade elementary school students participated in a group meeting, group interviews and journal writing. The results indicated that mothers described their experiences as a critical first step outwards on the journey to independence. The role experiences of the mothers who participated in this study can be seen from three perspectives: Firstly, as mothers as individuals projecting a mother's worries onto their child and becoming a capable person to help their children adjust to a new school environment, secondly, as mothers as family members experiencing a more authoritarian parenting style and difficulties of co-parenting with their husbands and parents-in-law, and lastly, as mothers as members of the extended family systems experiencing communication difficulties regarding the public education system and feeling uncomfortable with other parents. The findings may be used to develop support programs as well as a channel for interacting with public education bodies and community agencies.

• Journal of Families and Better Life
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• v.28 no.5
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• pp.131-149
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• 2010

The purpose of this research was to explore the levels of ethical consumptions and related factors on ethics of undergraduates as consumers. For statistical analysis, Cronbach' ${\alpha}$, factor analysis, t-test, one-way ANOVA, Duncan's multiple range test, Pearson co-relationship analysis, and multiple regression analysis with a total of 761 questionnaires were conducted. The research results are summarized as follows. 1. The scores to measure ethical consumptions level of the undergraduates was ranged from 2.66 to 3.64, which were relatively low. 2. The ethical consumptions in the commercial transaction were found to have significant differences according to gender, college years, and religion. The ethical consumptions of current generation were found to have the significant differences depending on their gender, college years, major, parents's education level, monthly allowance, and religion. The ethical consumptions of future generation were found be significantly different based on their gender, college years, mother's education level, father's occupation, monthly household income, and monthly allowance. 3. The major variables affecting the level of the ethical consumptions in the commercial transaction were materialism, social responsibility, idealism and college years. The major variables affecting the level of the ethical consumptions of current generation resulted from social responsibility, frequency contact with the mass media about the ethical consumptions, religions, and materialism. Social responsibility, frequency contact with the mass media about the ethical consumptions, idealism, expenditure, experience about the consumption education and materialism were the factors affecting the level of the ethical consumptions of future generation.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.237-243
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• 2014

Heart sounds of patient's chest could be heard using an analog stethoscope. However, auscultation of a heart sound can be diagnosed differently by each doctor hearing it. Therefore the condition of each patient is determined by the subjective comments based on the hearing ability of a physician who has years of experience. In this paper, through analysis of heart sound and heart rate of the patient's condition, we will define minutely how to diagnose the condition of patient using a wireless digital stethoscope diagnostic system. And it is possible to perform an objective medical diagnosis by applying LCR (Level Crossing Rate) and to show the relationship of a disease using this system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.487-494
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• 2011

The safety valve used in LNG/LNG-FPSO ships plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of the pipes in the LNG piping system. The discharge coefficient is regarded as the most important factor in the valve performance. To satisfy the ship's classification, the discharge coefficient of the safety valve must usually be over 0.8. Despite the importance of understanding the flow phenomena inside the safety valve, the valve design is usually based on experience and experiments. We carried out a computational fluid dynamics (CFD) investigation using the ANSYS-CFX software. We observed the flow phenomena inside the valve and measured the discharge coefficients according to changes in the valve lift, which is the distance between the exit of the nozzle and the lower part of the disc plate. We verified our CFD results for the discharge coefficients using available experimental data.

• Industry Promotion Research
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• v.2 no.1
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• pp.63-68
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• 2017

In this study, we surveyed 63 workers from October 10, 2016 to October 28, 2016, and analyzed the effect of education and training on job stress. Using IBM SPSS Statistics 20, factor analysis 32 items were used to derive 4 factors and the significance was verified as p = .000. First, The effects of workplace's OJT education on job training and job stress were found to have a significant effect on job stress relief. Second, the correlation between job stress and job stress showed that OJT education (p <.01, ${\beta}=.526$) and Off-JT education (p <.01, ${\beta}=.508$) were highly correlated with work stress. Third, the difference between work stresses according to career did not have statistically significant effect. More than 10 years of experience, less than 3 to 6 years were more sensitive to work stress. In this study, it is important to verify the effect of education and training on job stress.

• Journal of the Korean Solar Energy Society
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• v.36 no.5
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• pp.73-89
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• 2016

To assure maximum economic benefits and the energy performance of solar water heating systems, the proper sizing of components and operating conditions need to be optimized. In recent years, a number of studies to design optimally solar water heating systems have been tried. This paper presents a design method for optimizing the various capacity-related and installation-related design variables based on life cycle cost using a genetic algorithm. The design variables considered in this study included the types and numbers of solar collector and auxiliary heaters; the types of storage tanks and heat exchangers; the solar collector slope; mass flow rates of the fluid on the hot and cold sides. The suggested method was applied for optimizing a solar water heating system for an elementary school in Seoul, South Korea. In addition, the effectiveness of the proposed optimization method was assessed by analyzing the obtained optimal solutions of six case studies, each of which was simulated with different solar fractions. It is observed that a trade-off between the equipment cost and the energy cost results in an optimal design that yields the lowest life cycle cost. Therefore, it could be helpful to apply the optimal solar water heating system by comparing the various design solutions obtained by using the optimization method instead of the engineer's experience and intuition.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.197-204
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• 2011

In this paper, There is a study of a smartphone-based App for e-learning when the process control of manufacturing. First, That is obtained the control limit lines after inputted by the measured data and able to look up the assignable causes and then can display those causes. A User of this App can access the record about assignable causes using the record menu and can use with an e-Learning tool. Because that were provided in the form of a control process theory and bulletin announcements. Helped to exchange information. In addition, the user's guide how to use this App. The result of this process control is provided by charts. The alarm message to the alertsymbol, depending on the level of color clearly was designed to UI which displays the results. After the questionnaire responses with respect to satisfaction of Utilization and satisfaction of the learning experience. The Utilization' satisfaction results Appeared that 82% of the participants were satisfied. And The learning's satisfaction results Appeared that 90% of the participants were satisfied.