• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.183-190
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• 2007

This paper presents the design of 860 MHz band transmitter for improving power amplifier's linearity using Cartesian feedback method. For eliminating the effects of gain, phase mis-match, and DC offset, we estimate the property variations using ADS software. The implemented Cartesian feedback transmitter exhibits IMD3 of -54 dBc at an output power of 43 dBm and this result shows that the linearity is improved for 22.4 dB, compared with the test of the power amplifier without Cartesian feedback system. Thus, we verify that the proposed Cartesian feedback transmitter can be applied to narrow-band transmitter systems.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.145-150
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• 2020

Water wall tube is one of the major factors consisting of a fluidized bed boiler and it plays very important role for the generation of electricity within the boiler. But these water wall tubes within the fluidized bed boiler are subject to the ware and corrosion caused by the high temperature gas and the flowing medium. If water leak is occurred, the secondary damage by the water leak will occur. As a result of that, the power generation efficiency decreases noticeably. Therefore, the maintenance of the water wall tube is very important. In this study, we designed a exciter sensor based on simulation and composed a remote field eddy current system for the defect evaluation of the outer water wall tube. Starting from the shape design of exciter, we conducted simulations for various design factors such as the water wall tube size, material, frequency, lift-off and so on. Based on the results, we designed the optimum exciter sensor for the water wall tube test within the fluidized bed boiler.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.9
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• pp.1333-1342
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• 2008

This study intended to evaluate the visual sensibility of textiles of knitting simulation through the painting function of SDS-ONE, a computer knitting system, with the use of various fancy yarns for hand knitting. For this study, six kinds of fancy yarns with difference manufacturing style and form were selected: loop yarn, tamtam yarn, fur1 yarn, fur2 yarn, ladder yarn, and tape yarn. In order to create a computer knitting simulation, paint function of SDS-ONE was employed to scan the fancy yarns for hand knitting with a scanner. Then, after the registration of the yarns as data, the yarn was brought in for knitting simulation in plain stitch with 3 gauge. After that a survey was conducted involving 60 female experts in their twenties. Using SPSS 12.0, factor analysis, reliability, Pearson correlation coefficient, ANOVA, Duncan test, and regression analysis were performed to analyze the collected data. First, according to the result of analyzing the visual sense factor, three factors of the 'inflexibleness/ruggedness sense', 'lightweight sense', and 'smoothness sense' was extracted. According to the result of analyzing the visual sensibility factor, three factors of the 'activity', 'grace', and 'purity' was extracted. Second, With regard to preference and purchase intention, the knitted fabric with tamtam yarn(H2) was preferred than the other samples, indicating that the respondents had intention to purchase it. As for word-of-mouth intention, H2 ranked the first place, implying the respondents had intention to recommend it to other people. Third, the examination of the use of products each knitting simulation knit found that sweater and muffler are the most appropriate knit products. And H2 was the most suitable sample for sweater and muffler products. This study tried to prove that knit textile can be visually evaluated through a computer knitting simulation without the actual knitting and then to provide accurate data to related companies or the academic circle.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.447-458
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• 2002

In this paper, we design and implement Wireless Transaction Protocol(WTP) and evaluate it for wireless transaction processing in mobile computing environments. The design and implementation of WTP are based on the coroutine model that might be suitable for light-weight portable devices. We test the compatibility between our product and the other products such as Nokia, Kannel and WinWAP For the evaluation of WTP, we use an Internet simulator that can arbitrary generate random wireless errors based on the Gilbert model. In our experiment, the performance of WTP is measured and compared to those of Transmission Control Protocol(TCP) and TCP for Transactions. The experiment shows that WTP outperforms the other two protocols for wireless transaction processing in terms of throughput and delay. Especially, WTP shows much higher performance In ease of high error rate and high probability of burst errors. This comes from the fact that WTP uses a small number of packets to process a transaction compared to the other two protocols and introduces a fixed time interval for retransmission instead of the exponential backoff algorithm. The experiment also shows that the WTP performance is optimized when the retransmission counter is set to 5 or 6 in case of high burst error rate.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.262-270
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• 2019

This study aimed to develop designs for an early screening questionnaire for developmental disorders among children from multicultural families in the Republic of Korea, who are at an increased risk of developmental disorders due to cultural and language barriers. Research on early screening questionnaires for multicultural families is extremely scanty, unlike that on ordinary early detection tests designed for the same category of disorders. Worse still, there have been no attempts made at overcoming the limitations of language-based and intercultural communication that are endured by multicultural parents and social workers in the field. Given the challenges, this study confirmed through professional seminars the present status of early developmental disorder screening questionnaires and the necessity for developing specialized versions for multicultural children. Then the study identified the needs of the stakeholders by employing surveys and interviews, and obtained insights and core design elements. These preceding implementations led to the creation of an early developmental disorder screening questionnaire for multicultural families. The test kit incorporates the style of illustrations preferred by multicultural parents, as well as a system of language-specific interpretation services. Produced in a leaflet format, the questionnaire will be used at support centers for multicultural families and for disabled persons in each district for the practical purpose of early screening of developmental disorders among multicultural infants and preschool children.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.5-12
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• 2011

When choosing the support pattern of tunnel, the characteristics of rock are identified from the result of the surface geologic survey, boring, and geophysical prospecting and laboratory test. And a rock mass rating is classified and excavation method and standard support pattern are designed considering rock classification, domestic and international construction practices, numerical analysis. According to the revised design standard for tunnel, it was recommended to classify the rock mass rating for the design of tunnel into a rating based on RMR. If necessary, it proposed a flexible standard allowed applying more atomized the rock mass rating and Q-System. Also, the resonable verification of the support pattern must be accompanied because the factors affecting the structure and behavior of ground during the construction of tunnel are the main factors of uncertainty factors such as the nature of ground, ground water and the characteristics of structural materials. These days, such verification method is getting more specialized and diversified. In this study, the empirical method, numerical analysis and comparative analysis of in situ measurements were used to prove the reasonableness in the support pattern by RMR and Q-value on the Imha Dam emergency spillway.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.2
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• pp.1-7
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• 2021

The concrete deck slab at the continuous span support of the steel box girder bridge is a structure that is combined with the upper flange. It is a structure that can cause tension cracks in the deck slab at the support causing problems such as durability degradation in long span bridges. This is because the tensile stress in the longitudinal direction of the slab exceeds the design tensile strength due to the effects of dead load and live load when applying a long span. Accordingly, it is necessary to control tensile cracking by adding a reinforcing bar in the axial direction to the slab at the support and to introduce additional compressive stress. To solve this problem, a structural system of a steel box girder bridge was proposed that introduces compressive stress as PS steel wire tension in the tensile stress section of the upper slab in the continuous support. The resulting structural performance was compared and verified through the finite element analysis and the steel wire tension test of the actual specimen. By introducing compressive stress that can control the tensile stress and cracking of the slab generated in the negative moment through the tension of the PS steel wire, it is possible to improve structural safety and strengthen durability compared to the existing steel box girder bridge.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.570-575
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• 2022

The MX-S2X, utilizing high-frequency broadband communication technology, provides a reliable connection between land, ship, and facilities. This technology is expected to be effectively utilized as a future maritime communication infrastructure in the upcoming mixed navigational situation among autonomous and manned and/or unmanned ships. Following the physical layer design and M&S-based performance analysis of the MX-S2X system to overcome maritime multipath fading, this paper confirms the optimized and detailed design of physical layer hardware and implemented it to verify the performance. The PER(Packet Error Rate) performance was then measured by configuring a test environment to verify the implemented hardware. The results showed that the performance degradation was 0.2 dB in the AWGN environment and 1.2 dB in the Multi-path Fading on Sea Environment, thus confirming the successful implementation of the physical layer.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.41-53
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• 1994

A SGTR accident postulated at Kori unit 1 is simulated with Mihama unit experience, which occurred on February 1991, to evaluate the capability of plant to cope with the transient. The system design and plant conditions of Kori Unit 1 are much similar with those of Mihama Unit 2. Therefore, special concern has been given to evaluate the sequence and the resulting consequence of the postulated SGTR accident at the Kori unit 1 An analysis is peformed as realistically as possible, with following the EOP of Kori unit 1. The result indicates that the leak through tube break terminates within about forty minutes, and the Kori unit 1 may be sufficient to cope with SGTR accident with same type of sequence. However, the reconsideration may be required for the design of Kori unit 1 which disconnects non-safety AC power from off-site power on SI signal generation. It may be pointed out that the content of EOP for SGTR accident is not enough to require operator's proper judgements. An analysis of SGTR accident tested in the LSTF which simulated the SGTR accident at the Mihama Unit 2 is peformed using the RELAP5/MOD3. The results indicates that the code yields in general good agreement with the test, except the break flowrate at the early stage of the event.

• 한국호스피스완화의료학회:학술대회논문집
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• 2004.07a
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• pp.100-102
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• 2004

Under the current medical system, a terminal patient and his/her family who are neglected inevitably face various aspects of crises including not only physical, but also psychological, social, economic, spiritual and legal problems. Nurses often look after many terminal patents with these types of complicated problems. Therefore, educating the nurses who will take care of such patents would greatly reduce stress so the patents end could their lives in peace and without losing their dignity. This research is a quasi experimental study of nonequivalent control group. A pretest-posttest design where a basic education program is developed for nurses, who frequently treat terminal patents, to understand the importance of the role of hospice and to apply their understandings to treat terminal lancer patents. A sample of the nurses were taken from those who were working in general wards at two general hospitals in Seoul during October, 2003${\sim}$December 2003. The study was composed of 46 experimental group and 43 control group. A basic hospice education program was developed by taking emphasized and overlapping parts from advanced practice hospice nurses education course, short-term education course, an extensive literature survey and by consulting three professionals as well. With the group of 5 professors with vast experiences in oncolgy, 5 nursing administrator, 3 nursing practitioner, the tentative first version of the program was developed and reviewed. Afterwards, by utilizing person to person interviews with 2 head nurses experienced with terminal patients, 1 nurse in charge of hospice, 1 nurse on the contents of the program, and a person to person rating on the educating medium by a nurse were performed. The final version of a basic education program was developed after the second revision. The hospice basic education program consists of introduction to hospice, hospice and commucation, management of pain for terminal cancer patients, physical management for terminal cancer patients, socio-psycological caring of terminal cancer patients and management of death and separation. Total education time was four hours organized into 50 minutes of instruction and 10 minutes of break. $Powerpoint^{(R)}$ software was used as the education medium. As research tools, "Knowledge on Hospice" was developed by the author after receiving a review from one expert. "Attitude of Hospice Nursing" was revised Kim(2001)'s attitude measuring tool which was based on Wang(1998), Kwon(1989), Park and Sung(1991)'s tool. "Liability on nursing terminal patients" was used as developed by Zarits(1980) and Mongomory(1985) translated by Lee(1985). For collecting data, preliminary investigation prior to 1 week of the hospice basic education program and post-investigations after 1 week and 4 weeks of the education were carried out for the nurses at a general ward who understood and agreed on the purpose of the program. Collected data were analyzed throughout t-test, $x^2-test$, Manova test and Bonferroni correction in $SAS^{(R)}$ program. The summary of the investigation is as follows: Hypothesis 1: "Educated experimental group would possess more knowledge on hospice compared to the un-educated control group" was supported after 1 (F=12.14, p=.00) and 4 (F=5.3, p=.02) weeks of education. Hypothesis 2: "Educated experimental group would take a positive attitude toward hospice nursing compared to the un-educated control group" was supported after 1(F=3.92, p=.05) and 4(F=5.05, p=.02) weeks of education. Hypothesis 3: "Educated experimental poop would feel less liability compared to the un-educated control group in nursing terminal cancer patients' was rejected. In this study, it was found that knowledge on hospice was significantly important. By applying hospice basic education programs to nurses, the education program helped nurses to take a positive attitude toward terminal patients. It was, however, seen that the education program had no effect on alleviating liability in nursing terminal patients. Therefore, it is expected that this educational program would help hospices and nurses at general wards to understand the concept and the role of hospice so that terminal patents, now neglected under current medical system, would be able to end their lives in peace.