• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.366-372
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• 2017

In this paper, the analysis of baluns that are inevitably required to design a differential low noise amplifier, The balun converts a single signal input from the antenna into a differential signal, which serves as an input to the differential amplifier. In addition, it protects the circuit from ESD(Electrostatic Discharge) coming through the antenna and helps with input matching. However, in the case of a passive balun used in general, since the AC signal is transmitted through electromagnetic coupling formed between two metal lines, it not only has loss without gain but also has the greatest influence on the total noise figure of the receiving end. Therefore, the design of a balun in a low-noise amplifier is very important, and it is important to design a balun in consideration of line width, line spacing, winding, radius, and layout symmetry that are necessary. In this paper, the factors to be considered for improving the quality factor of balun are summarized, and the tendency of variation of resistance, inductance, and capacitance of the balun according to design element change is analyzed. Based on the analysis results, it is proved that the design of input balun allows the design of low noise, high gain differential amplifier with gain of 24 dB and noise figure of 2.51 dB.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.740-746
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• 2007

The potential candidates for IT-SOFCs cathode materials, $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) and $La_{0.6}Ba_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LBCF) powders, were synthesized by a EDTA-citrate combined method from $Sr(NO_3)_2$, $Ba(NO_3)_2$, $La(NO_3)_3{\cdot}6H_2O$, $Co(NO_3)_2{\cdot}6H_2O$, $Fe(NO_3)_3{\cdot}9H_2O$, citric acid and $EDTA-NH_3$. The cathode performance of symmetrical electrochemical cells consisting of BSCF-GDC or LBCF-GDC composite electrodes and a GDC electrolyte was investigated using by AC impedance spectroscopy at the temperature range of 500 to $700^{\circ}C$. It was found that a single phase perovskite could be successfully synthesized when the precursor is heated at $850^{\circ}C$ for 2 h. Due to thermal expansion mismatch between BSCF and GDC, the composite cathodes with lower GDC content than 45 wt% were peeled off from the GDC electrolyte and their electrode polarization resistance was estimated to be high. The thermal expansion coefficient of BSCF-GDC composites was decreased with increasing the GDC content and the electrode peeling off did not occur in BSCF-45 and 55 wt% GDC composites. BSCF-45 wt% GDC composite electrode showed the lowest area specific resistances (ASR) of 0.15 and $0.04{\Omega}{\cdot}cm^2$ at 600 and $700^{\circ}C$, respectively. On the other hand, LBCF-GDC composite cathodes showed higher ASR than the BSCF-45 and 55 wt% GDC and their cathode performance were decreased with the GDC content.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.190-197
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• 2012

We employed the vinyl ethylene carbonate (VEC) as an electrolyte additive and investigated the effect of the electrolyte additive on the electrochemical performance in hybrid capacitor. The activated carbon was adopted as cathode material, and the $Li_4Ti_5O_{12}$ oxide was used as anode material. The electrolyte was prepared with the $LiPF_6$ salt in the mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate(EMC). We evaluated the electrochemical performance of the hybrid capacitor with increasing the amount of the VEC electrolyte additive, which is known as the remover of oxygen functional group and the stabilizer of the electrode by reducing the surface of electrode, and obtained the superior performance data especially at the addition of the VEC electrolyte additive of around 0.7 vol%. On the contrary, the addition of the VEC more than 0.7 vol% in the electrolyte leads to the degradation in electrochemical performance of hybrid capacitor, suggesting the increase of the side reaction from the excessive VEC additive. X-ray photoelectron spectroscopy (XPS) revealed that the addition of the VEC suppressed the formation of LiF component, which is known as the insulator, on the surface of electrode. The optimized addition of VEC exhibited the improved capacity retention around 82.7% whereas the bare capacitors without VEC additive showed the 43.2% of capacity retention after 2500 cycling test.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.442-454
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• 2002

It's noticed that the SA-DCT (Shape-Adaptive Discrete Cosine Transform) produces different 2-dimensional transform coefficients according as the first 1-dimensional transform is applied in horizontal or vertical direction for an arbitrarily shaped boundary block. Performing the first 1-dimensional transform in the direction, which has higher spatial correlation or smaller shifting distance, can compact the energy on the smaller number of AC coefficients around DC. This paper shows, experimentally, the compaction capability improvement by choosing the first 1-dimensional transform direction with higher spatial correlation or smaller shifting distance. Two adaptive selection methods are proposed to decide efficiently the spatial direction with higher correlation in a boundary block. One is based on the gradients between DC coefficients of neighboring and current blocks, and the other is based on the final coding efficiency that means the number of bits required for coding the block. Using the MPEG-4 video coder, the proposed method shows coding efficiency gain up to 10.87% compared to the conventional SA-DCT method.

• Journal of Korean Academy of Nursing
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• v.24 no.4
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• pp.696-705
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• 1994

This study was done to provide a basis for home health care management for women following Cesarean delivery. Furthermore it was initiated as an possible application of home health care in the future. In this study, client selection criteria was developed by the researcher and assessment tools for home health care, recording system and problem oriented recording system were revised from Jun's(1993) methods. The selection criteria tool for home health care for women who had a Cesarean delivery was structured and consisted of five areas : physical status, functional status, psychological-emetional status, educational needs status and environmental status. The structured assessment tool consisted of general items, obstetric history, past medical history, methods of feeding, medications taken before ad-mission, laboratory results, discharge instructions, discharge medications, family tree, economic status, environmental status, a map, health assessment of women and their newborns. The visit note consisted of the date : nursing problems : nursing process including initial assessment : nursing goals : visit plan : health status of the postpartum women and their newborn : nursing diagnoses : nursing implementation evaluation : summary : next visit plan and revision. The problem oriented recording system consisted of the date, problem numbers, nursing diagnoses, problem appearance date, problem resolution date. The results of the research are as follows : The seven cases having had a Cesarean delivery were discharged on an average on the 5th day after the Cesarean birth. The total number of home visits was 13. According to Cordon's functional health patterns the total possible nursing diagnoses was 34 diagnoses for the methers and their newborns. Among the 34 diagnoses, there were 13 diagnoses in the health perception /management pattern, 7 in the psychosocial health perception / management pattern, 8 in the psychosocial self-perception, 2 in the nutrition / metabolism pattern of physical function, 2 in the knowledge deficit of newborn management, anxiety related to newborn management, knowledge deficit related to disease process of new-born, anxiety related to disease process of newborn anxiety related to prognosis of baby's condition, knowledge deficit related to newborn jaundice each appeared once. The changes in the number of nursing diagnoses was related to not the number of visits but to the number of nursing diagnoses decreasing. The con-tent of the home health care was categorized ac-cording to assessment, direct care, counseling, education, family care. The recommendation based on the results of this research are Home health care nurses for Cesarean postpartum women and their neonates requires comprehensive knowledge of pregnancy, delivery, and the postpartum period and of the neonate so that they can provide appropriate care and holistic views. Most of cases terminated after the second visit, this outcome may be related to the subjects being discharged on the 5th day after delivery. Therefore, study done with earlier discharge after delivery may have different outcome. It is very hard to assess psychological aspects that need follow-up and to develop communication channels.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.332-340
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• 2017

This study aims to propose a new optimization-based approach for design and analysis of the stand-alone hybrid energy supply system using renewable energy sources (RES). In the energy supply system, we include multiple energy production technologies such as Photovoltaics (PV), Wind turbine, and fossil-fuel-based AC generator along with different types of energy storage and conversion technologies such as battery and inverter. We then select six different regions of Korea to represent various characteristics of different RES potentials and demand profiles. We finally designed and analyzed the optimal RES stand-alone energy supply system in the selected regions using multiobjective optimization (MOOP) technique, which includes two objective functions: the minimum cost and the minimum $CO_2$ emission. In addition, we discussed the feasibility and expecting benefits of the systems by comparing to conventional systems of Korea. As a result, the region of the highest RES potential showed the possibility to remarkably reduce $CO_2$ emissions compared to the conventional system. Besides, the levelized cost of electricity (LCOE) of the RES-based energy system is identified to be slightly higher than conventional energy system: 0.35 and 0.46 $/kWh, respectively. However, the total life-cycle emission of $CO_2$ ($LCE_{CO2}$) can be reduced up to 470 g$CO_2$/kWh from 490 g$CO_2$/kWh of the conventional systems.

• Imaging Science in Dentistry
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• v.30 no.3
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• pp.155-158
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• 2000

The purpose of this paper is to explain the making procedure and the usage of receiver operating characteristic (ROC) curve for interpretation of radiographic images. The conventional radiograms obtained after the creation of the lesions in the acrylic plates and were enhanced in color. The observer were informed of which tooth to examine, the 'a priori' probability of a lesion present and the approximate diameter of the lesions. The two groups of films were interpreted separately by the same observer using the same rating scale. The following rating scale was used: A; definitely no lesion, B; probably no lesion, C; not sure, D; probably a lesion, and E; definitely a lesion. In analysis, for each observer the diagnostic results in terms of true positive (TP) and false positive (FP) decisions were plotted on a graph. The lowest point on the graph represents the TP and FP when only decisions designated as E according to the rating scale are included. The next point shows the TP and FP values when diagnoses designated as D are added and so forth. By connecting such plot points, a receiver operating characteristic (ROC) curves is obtained. The area under the curve represents the diagnostic accuracy resulting from a diagnostic performance at pure chance level and a value of 1.0 at perfect performance. This method has been known as an useful method to detect the minute difference for each radiographic technic, each observer and for the different lesion depths.

• Journal of Radiation Protection and Research
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• v.8 no.2
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• pp.15-35
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• 1983

High voltage paper-electrophoresis of fission products from 24 hour neutron-irradiated and 150 days-decayed 90% highly enriched uranyl nitrate solution has been carried out by using the specially designed migration apparatus. The separation of Zr-95 and Nb-95 from the other fission products is possible under the migration condition of 0.1 $M-HClO_4$ (pH=0.85), 0.05 M-HCl+0.09M-KCl (pH=0.9), 0.1M-HCl (pH=1.1) and 0.01 M-HCl (pH=2.0). Zr-95 and Nb-95 are separated out at+1cm from the fiducial point. The separation of Zr-95 and Nb-95 from each other is possible under the migration condition of 0.1 $M-HClO_4$, 0.05 M-HCl+0.09 M-KCl, 0.1 M-HCl and 0.1 M-HAc+0.1 M-NaAc (pH=4.68) together with 2% ammonium oxalate. Nb-95 is separated out at $-6{\sim}-7cm$ from the fiducial point and Zr-95 at $+1{\sim}-lcm$. The separation of Ru-103 from the other fission products is possible under the migration condition of 0.025 $M-Na_2CO_3+0.025\;M-NaHCO_3$ (pH=10.0), 0.01M-$Na_3PO_4$ (pH=11.7) and 0.1 M-NaOH (pH=13.2). Ru-103 migrates towards the anode -6cm, -4cm and -3cm, respectively.

• Journal of the Korean Society of Costume
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• v.29
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• pp.5-22
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• 1996

the present thesis aims to contribute to the further development of the men's wear indus-try in Korea which now confronts the need to adjust itself more actively to the conditions of the coming age of internationalization and free trade. To achieve this this thesis suggests the trade should provide for the changing domestic needs on theone hand and refine its wares as high value-added products in compe-tition with those from the advanced countries in fashion industry on the other, The history of the 'suit' the standard men's attire dates back to 1850 when the 'Ditto suit' was introduced composed of coat waist coat vest and trousers to remain virtually unchanged till the end of the nineteenth cen-tury and the modern men's wear originated in Britain. In Korea since the introduction of western clothes from 1876 custom-made suits had been dominant until 1944 while western clothes earned popular currency between 1945 and 1964 and ready-made suits began to spread with their advantages recognized in terms of practicality convenience and functionality The next phase from 1965 to 1985 witnessed the establishment of a number of ready-made brands although custom-made suits stayed in their height of prosperity until 1975. The turn-ing point for the men's wear industry came in 1975 when high-calss ready-made brands be-gan to turn up with the arrival of large companies in the market matching the change in consumers' life style. The men's wear market went through further diversification and specialization dur-ing the years between 1985. and 1990. Around the year 1990 however the expansion of the business suit industry came to slow down ac-companied by an oversupplied market. The fashion of pragmatism in the 1990s called for the growth of the casual wear department and as consumers' life style became more and more individualized conscious dressing in accord ance with T.P.O established itself as an important branch of culture, Such casual boom is likely to aid in promoting Korea's men's wear indus-try to peer with that of advanced countries. Consumers' fashion sense is now ahead of the trade's as well as being shortcycled highly individualized stylized and diversified. To meet consumers' demands under such circum-stances each company is required to develop its unique soft Know How based on accurate information and strategically specialized plan-ning. The trade should convert its hithero producer-oriented strategy to a new consumer oriented one and actively lead the needs and purchasin g pattern of consumers by providing an efficient and reasonable price policy with optimum supply of merchandise and also by presenting 'our' trend suited to our circum-stances.

• Journal of the Korean Society of Costume
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• v.29
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• pp.171-182
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• 1996

This thesis is concerned with the study of the court attire the typical attire of the ju-dicial world in a point of time that more than 100 years have passed since the introduction of the modern judical system. In recognition of the fact that compiled data of the official uni-form or attire in Korea are insufficient this study placed its signification on the provision of information with focus on attire. As a result of studying court attire in Korea the conclusion was made as follows: Firstly Official attires in Yi Dynasty were divided by wearing embroidered insignia on the breast and the back of an official robe ac-cordint to court rank as well as by wearing Sa-mo in wadded clothes of Dan-ryeong and attaching all sorts of appurtenances including bands and shoes The Minister of Justice was equipped with Ho-pyo Dae-sa-heon equipped with Hae-chi the mayor of Seoul equipped with Un-an In the era of the Kng Young-jo the minister of Justice had no change in its of-ficial robe but the mayer(Pan-yun) of Seoul (Han-sung-bu) had Un-an(wild geese in clouds) changed into Un-hak In the King Ko-jog era the minister of Justice had Ho-pyo changed into Ssang-ho and the mayor of Seoul had Un-hak changed into Ssng-hak on embroideved insignia on the breast and back of an official robe. Laws and regulations concerning court attire began with the In-judgement Full-dress Uni-form Requlation for official-level Clerical Staff below the ordinary staff the Issue No. 14 of the Royal Ordinance in 1906 provided as $\ulcorner$the matter cincerning the Dress Regulation of the Tribunal staff of the Cho-sun Government-General$\lrcorner$the Issue No. 222 of the Royal Ordi-nance in 1911 and changed into$\ulcorner$the Regu-lation on the Dress of Judge Prosecutor At-torney and Law Count Clerk$\lrcorner$the Issue No. 12 of the Supreme Court Rule in 1953 affter the establishment of Korean Government since emancipation from the Japanese rule and into $\ulcorner$the Regulation concerning the Court Attire of Judge and law Court Clerical Staff$\lrcorner$the Issue No. 516 of the Supreme Court Rule in 1966. The judicial system in Korea is the system introduced from the foreign country rather than autogenously developed. And it came to pass through the Japanese colonial period it the beginning that it took root in Korea n was not stabilized in harmony with our native tradition. Accordingly the attare regulation in the judicial system took root in our society by accepting the Japanese attire regulation as it was and judical officials have come to wear the count attire similar to that of the Japanese imperialist era due to its influence though Korean independent goverment was established together with liberation form the Japanese rule. The more regrettable thing is that the current court attire has maintained the form greatly influenced by the U. S. court attire. Fortunately as the judicial circles have recently raised their voices for change in the court attire it has been told that the forma-tion of a meeting for a new court attire has been under way. The birth of the court attire into Which our tradition is sublimated is expected. This study end up with thinking that the must Korean thing is the most global thing in this era that people in the world are clamoring for globalization.