• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.700-707
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• 2014

In this paper, we propose the noise reduction method by using the eigenfilter in cyclic prefix system based on SNR. To obtain the signal eigenvectors for the eigenfiltering, we propose a method of obtaining the autocorrelation matrix by exploiting the circulant property of the received block which results from the cyclic extension of the OFDM symbol. Since the structures of the transmitter and the receiver are not changed, the proposed method is easy to apply to the conventional OFDM system. To verify the proposed method, we evaluate the persistency of excitation (POE) criterion for the input and demonstrate the effectiveness of the proposed method in the simulation results.

• Solar Energy
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• v.18 no.3
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• pp.41-50
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• 1998

The purpose of this study is to analyze the energy consumption status for various building types in Taejon. 35 sample buildings were classified into 8 building types, i.e., sports center & swimming pools, hotels, telecommunication exchange service facility, hospitals, research laboratories, department stores, exhibition galleries, universities. According to analyses, energy consumption patterns varies significantly for each building type. Sports centers consumes highest rate(689 $Mcal/sqm{\cdot}yr$) and universities lowest rate(86 $Mcal/sqm{\cdot}yr$) among selected building types.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.150-157
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• 2004

Carbon dioxide ($CO_2$, R-744) has become a very popular issue in application to refrigeration and air conditioning systems as a natural refrigerant. An experimental study has been carried out to investigate miscibility and the vapor pressure of refrigerant R-744 in the presence of lubricant oil. This is of particular interest in the selection of the lubricant oil for the compressor of a refrigeration system or an air conditioning system using the refrigerant R-744. The experimental set-up consists of the equilibrium cell, measuring devices, the vacuum pump, the constant temperature bath and relevant connecting pipes made of stainless steel. Five lubricant oils, such as mineral oil (Naphthenic), AB (Alkyl Benzene) oil, PAO (Poly Alpha Olefin) oil, PAG (Poly Alkylene Glycol) oil and POE (Polyol Ester) oil are considered in the present study. Test runs were conducted with the oil concentration range from 5 to 50 wt％, and the temperature range from -10 to 1$0^{\circ}C$ with 2$^{\circ}C$ intervals. The miscibility results are visualized and correlated with the vapor pressure for the individual test components.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.31-37
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• 1999

In order to predict thermodynamic performance of refrigeration system, it is required to know the oil concentration of the refrigerant/oil mixture. The current method to measure the oil concentration is to extract the working mixture and then to measure the oil weight. However, it is Quite necessary to estimate oil concentration without any extraction of the working fluid. In this study a new method and working equation is presented as follows. It is based on the measurement of spedific gravity and temperature : $$C=a+b{\times}t+c{\times}t^2+(d+e{\times}t+f{\times}t^2){\times}SG$$ C is oil concentration, t is temperature($^{\circ}C$), SG is specific gravity of mixture and a~f is coefficients. The oil concentration ranges over 0~12 wt% and the temperature ranges over $20{\sim}50^{\circ}C$. The specific gravity and temperature are measured using the on-line densimeter and thermometer. This working equation enables to predict the oil concentration without any extraction of the mixture. This equation can be applied for R-12/Naphthenic oil and R-134a/POE oil oiquid mixtures.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.35-40
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• 1993

Alkaline cleaning agent(ACA) was prepared by blending of POE(4)octadecylmine(S-204), $Na_2CO_3$, sodium orthosilicate(Na-OSi). Tetronix T-701(T-701), and MJU-100A. The physical properties of ACA tested with steel specimen showed the following results. The cleaning powers of ACA-6(S-204 80g/$Na_2CO_3$, 160g/Na-OSi, 80g/T-701, 60g/MJU-100A, 20g mixture) for press-rust preventing oil was 98% and 99% degreasing at 2wt%, $70^{\circ}C$ and $90^{\circ}C$, respectively : for quenching oil, the cleaning power of ACA-6 was 95% degreasing at 2wt% and $70^{\circ}C$. From these results, it was ascertained that ACA-6 exhibited a good cleaning power. Foam heights measured immediately after foaming by Ross & Miles method and Ross & Clark method at 3wt%. $60^{\circ}C$ were 17mm and 40mm, respectively. As the result, ACA-6 was proved a good low foaming cleaning agent.

• The Journal of Internal Korean Medicine
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• v.12 no.1
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• pp.166-182
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• 1991

This study has been carried out to investigate the cause and symptom of Hae su (咳嗽) cause by a cold referring to 25 literature. 1. Cause : wind (風), cold (寒), heat (署), moisture (濕), dryness (燥), fire (火). It appears to cause double and above. 2. Symptoms : PunghanHaeSu (風寒咳嗽) ; HaeSu (咳嗽), Balyul (發熱), DamHueSaegBaeg (痰稀色白), Hu Yang Sung Tag (喉痒聲濁), BiSaegYuChe (鼻塞流涕), OhPungHan (要風寒), DooShinTong (頭身痛), TaeBaqBaeg (笞薄白), Maeg Bu Gin (脈浮緊). PungYeulHaeSu (風熱咳嗽) ; HaeSu (咳嗽), DamJo (痰稠), SaegHwang (色黃), KaegChulBulSang (喀出不痰), KuKallnTong (口瀉咽痛), BalYeul (發熱), OhPungYuHan (要風有肝), HogYuDuTong (或有頭痛), TaeBagHwang (笞薄黃), Maegbusag (脈浮數). JoYeulHaeSu (燥熱咳嗽) ; KunHaeMuDarn (乾咳無痰), HogDamJungDaeHyulSa (或痰中帶血絲), HaelnHungTong (咳引胸痛), BiJolnKun (鼻燥咽乾), pliogyuOhPungBalYeul (或要風發熱), TaeBagHqangIKun (笞薄黃而乾), MaegSeSag (脈細數). 3. Treatment ; PungHanHaeSu ; SoPungSanHan (疏風散寒), Sun PaeJiHae (宣肺止咳), PungYeulHaeSu ; SoPungchungYeul (疏風淸熱), SunPaeJiHae (宣肺止咳), JoYeulHaeSu; CheongPoeYunJo (淸肺潤燥), SaengJinJiHae (生津止咳). Basing on the literature research, I found that Hae Su (咳嗽) caused by a cold belong to category of YugEum(六淫).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.307-312
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• 2019

Transient earth voltage (TEV) signals propagate on metal surfaces when partial discharge (PD) occurs due to the deterioration of insulation performance in the operation of gas-insulated switchgears (GIS). A TEV sensor has advantages of high sensitivity and convenient installation for detecting PD defects. However, the TEV sensor depends on imports in domestic and detailed studies have not been conducted. In this study, a sensor was designed and fabricated by the TEV principle and its response characteristics were evaluated for detecting PD defects, which were simulated as protrusion on conductor (POC), protrusion on enclosure (POE), and free moving particle (FMP) defects. Finally, the PD-induced TEV signals were measured and phase-resolved partial discharge (PRPD) patterns were analyzed to identify the type of defect.

• Journal of the Korean Society of Food Culture
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• v.36 no.1
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• pp.28-39
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• 2021

This study considered the rite of passage ceremonial food in the Mid-Choseon Period through the rite of passage ceremonies, food, and ingredients recorded in the Seoul Noble Ohhweemun Family Diary Shaemirok. The research used a contents analysis method through case studies. The noble families in the Mid-Choseon Period deemed the Jerye to be the most significant out of the traditional ceremonies. The nobles practiced the Sadehbongsah and the Yoonhweebongsah ceremonies for their ancestors. The Rite of passage ceremony required fruit. Of fish and birds, pheasants were used frequently during the ceremonies. Noble families, specifically the richer families, could sustainably normalize the rite of passage ceremonies against the elements. Seasonal ingredients were generally harvested even during spring and winter in large amounts. One of the last rites of passage food by Garye displayed diverse ingredients, such as Bangaeng, Myun, Tang, Uhyookjuk, Poe, Chae, Hae, and Silgwa. Such ingredients prove that the normalization of rite of passage ceremony food was well established and practiced. On the other hand, the birthday rite of passage food did not conform to a specific rite of passage normalcy or preparation. Instead, the birthday food showed a flexible menu of seasonal delicacies that were not confined to a particular traditional formula.

• The Journal of Information Systems
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• v.31 no.3
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• pp.109-129
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• 2022

Purpose The purpose of this study is to examine whether customers' shadow work and risk perception have an impact on revisit intention to the fast-food restaurant, with mediating role of different types of attribution tendencies. We also added perceived unfairness in the research model, in order to verify its mediating effect on the relationship between attribution tendencies and revisit intention. Design/methodology/approach Applying the shadow work perspective and attribution theory, we designed a research model to confirm the hypotheses. After collecting the data from 331 customers who have used self-service technology in a fast-food restaurant, we conducted an analysis of measurement model and structural model by using Smart-PLS 3.0. Findings This study confirmed that Forced Use of self-service technology can enhance the tendency of dispositional attribution which would negatively affect perceived unfairness and revisit intention. On the other hand, affective risk perception was proven to affect situational attribution, which positively affects revisit intention.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.83-94
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• 2023

In order to devise a rebar usage optimization algorithm, it is necessary to calculate the exact rebar length and revise the arrangement of rebars into special lengths. However, the process of rearranging numerous rebars and manually calculating their quantities is time-consuming and requires significant human resources. To address this challenge, it is necessary to develop an algorithm that can automatically estimate the length of rebars and calculate their quantities. This study aims to create an automatic estimation algorithm that improves work efficiency while ensuring accurate and reliable calculations of rebar quantities. The algorithm considers various factors such as concrete cover, hook length, development length, and lapping length, mandated by the building codes, to calculate the quantity of rebars for wall structures. The effectiveness of the proposed method is validated by comparing the rebar quantities generated by the algorithm with manually calculated quantities, resulting in a difference rate of 1.14% for the hook case and 1.37% for the U-bar case. The implementation of this method enables fast and precise estimation of rebar quantities, adhering to relevant regulatory codes.