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        검색결과 657

        67.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the impacts of cane-based fruiting position on fruit quality at harvest in a golden-flesh kiwifruit variety, ‘Sweet Gold’ (Actinidia chinensis var. chinensis). The vines were grown on a pergola-trained system, under a protected plastic film house in Jeju, Korea. The cane-based fruiting positions were classified into six sectors with three sectors acropetally from the trunk to the apex of the leader, and two sectors acropetally from the leader to the apex of the cane. Fruits positioned in sectors far away from the trunk (sectors three and six) tended to be heavier, whereas fruits in sectors close to the trunk (sectors one and four) exhibited higher dry matter, soluble solid contents, and flesh coloration. The highest firmness was obtained at the fruits positioned far from the trunk and leader (sector six). Titratable acidity was slightly impacted. The highest starch content was obtained from the fruits of sector six far from the trunk and leader, whereas the highest soluble sugar content was from sector one proximal to the trunk and leader. Results indicate appreciable variations in fruit quality parameters at harvest, among fruits at different fruiting positions within vines. However, these variations were inconsistent over the years, and there were no distinct correlations among these fruit quality parameters.
        4,000원
        68.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the massive impact of COVID-19 on society, beyond the numbers of confirmed cases and deaths, there remains a lack of large-scale data depicting the effects of the virus on the society of the Republic of Korea. To fill this gap, we collected 1.822 million news articles with more than 1 billion morphemes from January 2020 to June 2022, creating a Korean version of the Coronavirus Corpus. This corpus is introduced in the current study. In addition, to demonstrate how such massive corpus can be utilized, we conducted information theoretical analyses to see how the stance of the press media on topics such as vaccines and social distancing affected the COVID-19 situation in the Republic of Korea. Specifically, we utilized several computational linguistic skills including concordance building and sentiment analysis through both traditional and machine learning techniques and measured the transfer entropy to estimate the impact with information theory. The results suggest that the overall impact of the press media on the society was minimal to non-existent.
        7,700원
        69.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aster 속에 속하는 자생식물로는 눈갯쑥부쟁이, 개쑥부쟁이, 쑥부쟁이, 벌개미취, 참취 등이 있는데, 대부분 식용 또는 관상용 으로 많이 활용되고 있다. 특히 눈갯쑥부쟁이는 제주 한라산(표 고 1,200~1500m근처)에서 자생하는 한반도 특산식물로써, 다른 Aster 속과 다르게 포복성을 가지고 있고 개체당 소화의 수가 많아 관상가치가 매우 뛰어나다. 또한 파종 당해년에도 개화가 가능하기 때문에 유망한 관상식물 자원이라 할 수 있다. 본 연구 에서는, 한반도 특산 눈갯쑥부쟁이의 유전자원 보존 및 대량번 식을 위한 기초자료를 확보하고자 종자의 발아특성 및 휴면유형 을 분류하였다. 눈갯쑥부쟁이 종자는 형태적으로 완전하게 발달 된 배를 가지고 있고, 배양 72시간 내에 145%의 수분을 흡수하 였다. 4가지 온도조건(4°C, 15/6°C, 20/10°C, 25/15°C)에 배양한 결과, 광조건에서는 각각 67.0%, 58.9%, 62.2%, 71.6% 발아하였 고, 암조건에서는 각각 79.4%, 65.9%, 65.9%, 49.1% 발아하였 다. 저온층적처리(4°C) 실험 결과, 최종 발아율에는 큰 차이가 없었으나, 층적처리 기간 동안에도 발아하는 특성을 관찰하였 다. GA3처리 후 25/15°C에 배양한 결과, 0, 10, 100, 1000mg·L-1 처리에서 각각 57.9%, 68.3%, 74.9%, 63.9%의 발아율을 보였 다. 15/6°C에 배양한 경우에는 각각 78.3%, 62.8%, 72.2%, 55.9% 발아하였다. 본 연구에서는 위 실험들을 통하여, 약 80% 정도는 non-dormant 종자로, 나머지 약 20%는 생리적 휴면 (physiological dormancy)을 가지고 있는 것으로 판단되었다.
        4,000원
        70.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korea's Corona 19(COVID-19) quarantine, referred to as 'K-Quarantine', is a globally recognized quarantine system that has achieved both conflicting goals: health and economy. The quarantine system represented by 3T(Test-Trace-Treat) is not a method of blocking an area, but a method of screening and treating infected and non-infected persons. The screening center, one of the key elements of this screening treatment system, has evolved to suit the timing and situation of COVID-19, and has succeeded in initial response by conducting large-scale tests quickly and safely. By analyzing the evolution of screening centers that produced such significant results from a problem-solving point of view, it proved its meaning as a practical success case of creative problem- solving. In addition, the usefulness of TRIZ (Russian abbreviation of Theory of Solving Inventive Problem), a creative problem- solving theory, was confirmed through an analysis of actual verified cases of COVID-19 response. TRIZ is a problem-solving theory created by analyzing the regularity of invention patents, and is widely used not only in the technical field but also in the non-technical fields such as design, management, and education. The results of this study are expected to provide useful meaning and practical examples to researchers interested in system analysis and TRIZ application from a problem-solving perspective.
        4,200원
        71.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pair trading is a statistical arbitrage investment strategy. Traditionally, cointegration has been utilized in the pair exploring step to discover a pair with a similar price movement. Recently, the clustering analysis has attracted many researchers' attention, replacing the cointegration method. This study tests a clustering-driven pair trading investment strategy in the Korean stock market. If a pair detected through clustering has a large spread during the spread exploring period, the pair is included in the portfolio for backtesting. The profitability of the clustering-driven pair trading strategies is investigated based on various profitability measures such as the distribution of returns, cumulative returns, profitability by period, and sensitivity analysis on different parameters. The backtesting results show that the pair trading investment strategy is valid in the Korean stock market. More interestingly, the clustering-driven portfolio investments show higher performance compared to benchmarks. Note that the hierarchical clustering shows the best portfolio performance.
        4,000원
        73.
        2022.05 구독 인증기관·개인회원 무료
        The decommissioning cost of a nuclear power plant (NPP) is largely composed of activitydependent costs, period-dependent costs, and collateral costs. And activity-dependent costs for each decommissioning activity are composed of five cost elements: Removal, decontamination, packaging, shipping and disposal. Among these, the removal cost elements are calculated by multiplying the appropriate inventory data element by the corresponding unit factors (UF), which are developed in terms of labor hours to perform an activity on a per unit basis. The labor hours included in UF is calculated under theoretical working conditions, which, after being multiplied by labor rates, composes unit cost factor (UCF) along with material cost. In the actual working conditions, there are number of factors that increase the time needed for performing a task. The effects of these factors are taken into consideration by means of work difficulty factor (WDF), expressed as a percentage of increase of the working time, comparing to an unimpeded working situation. WDF, by increasing the labor hours and consequential labor cost in UCF, makes it possible to calculate the actual removal cost. There are about five types of adjustment factors commonly used as WDF: Height, Respiratory protection, Radiation, Protective clothing, Work break. Considering the different working conditions, all of the five factors’ combination could be used theoretically, which results in the huge increase of the number of WDFs. For practical purpose, two representative WDF application methods has been used in the dismantling decommissioning cost evaluation program: A separate development of the UCFs, WDFs applied to the decommissioning area. In the first method, all of the UCFs, having different working environment, should be developed separately by the cost estimator. In the second method, UCFs are to be allocated to the relevant decommissioning areas where WDF sets are predefined by the cost estimator. In this study, the components of the decommissioning cost, the relation between UCF and WDF, and WDF application methods were reviewed. The result of review implies that WDF has a great influence on decommissioning cost. Additionally, since WDF application methods have somewhat limitations and complexity, their characteristics should be sufficiently examined by the user before being used.
        74.
        2022.05 구독 인증기관·개인회원 무료
        When a permanently-closed nuclear power plant is to be decommissioned, large structures targeted to be cut in the process include a steam generator, reactor, and reactor coolant pump (RCP). Although there are sufficient preliminary studies being done on these structures to assess the radiation exposure dose, relatively fewer studies are underway regarding pressurizers. Therefore, preliminary evaluations are required to prevent workers from being overexposed to radiation coming from a pressurizer and to avoid an unnecessary increase in the decommissioning cost. This study created a cutting scenario based on disposal drums for solid radioactive wastes. The cutting scenario was based on 200-liter and 320-liter drums for solid wastes and on the assumption that all cutting operations were done 100 centimeters away from the structure to be cut. When are cutting process of a Pressurizer is carried out per scenario, the 200-liter drum produces 272 pieces, whereas the 320-liter counterpart generates 234 pieces. Given that South Korea allocates 75,550 KRW per liter (based on 200 L) for the disposal cost, an increase in the number of drums leads to an exponential growth of the decommissioning cost, which fuels the need to establish more organized cutting strategies. Meanwhile, in terms of radiation dose, plasma, laser, and flame cutting techniques were estimated to record 0.232 mSv, 0.299 mSv, and 0.213 mSv respectively for 200 L, and 0.195 mSv, 0.251 mSv, and 0.179 mSv respectively for 320 L (based on DF-90). When compared with the annual dose limit of 100 mSv (0.0057 mSv·hr−1), the above numbers registered for both 200 L and 320 L were estimated to satisfy the dose limit, with only a negligible difference in the dose between the two capacities. The results generated from this study are expected to be utilized as a meaningful basis to identify applicable cutting techniques of a pressurizer as part of the decommissioning operation and to establish its cutting plans in compliance with ALARA.
        75.
        2022.05 구독 인증기관·개인회원 무료
        Radiological characterization, one of the key factors for any successful decommissioning project for a nuclear facility, is defined as a systematic identification of the types, quantities, forms, and locations of radioactive contamination within a facility. This characterization is an essential early step in the development of a decommissioning plan, in particular during transition period after permanent shutdown of the facility, and also to be used for classification of decommissioned radioactive wastes so that their disposal criteria can be met. Therefore, the characterization should be well planned and performed. In the transition period, the characterization information developed during the operational phase is usually reexamined with respect to the applied assumptions, the actual status of the facility after shutdown, the accuracy of the required measurements and changes in its radiological properties to support the development of the final decommissioning plan. Based on some national (Korean, USA’s and Japanese) laws including the related regulations, and some related documents published by OECD/NEA, IAEA, and ASTM, key elements of radiological characterization, which should be developed in the transition period, could be proposed as the followings. The key elements might be an operational history including facility operation history and contamination by events and/or accidents, radiological inventory of the facility and site area, characterization survey including in-situ survey and/or sampling and analyses, radiological mapping (which is able to identify radiological contamination levels of SSCs, and the facility area and, if contamination may be suspected, the surroundings) with tabulating, residual radioactivity (or derived concentration guideline levels) of selected major radionuclides for remediation of the site, (retainable and retrievable) recording, and quality control and quality assurance. In review process of the operational history, interviews of current or former long-tenured knowledgeable employees of the facility should be conducted to identify conditions that may have been missing from the records.
        76.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The antioxidant effects by pre-treatment of Hutgae fruit water and ethanol (30°, Soju) extract on refrigerated eels were analyzed. The antioxidant activities were measured through DPPH and ABTS scavenging effect, values of acidity, peroxide, carbonyl, and TBA. The peroxide prevention effects of linoleic acid and eel oil were also assessed. Regarding DPPH radical scavenging, Hutgae ethanol extract presented higher scavenging effects than vitamin C 5 mM solution (p<0.05). The eel’s peroxidation degree was measured through 21 days of refrigeration after cleaning and immersion into the extract solution for one hour. Upon measuring the values of four different peroxide indicators, those of eels pre-treated with Hutgae extracts were lower than those of eels untreated. The POV of Hutgae ethanol extract, vitamin C 5 mM, and the control was 11.1, 11.3, 15.5 meq/kg, respectively. Hutgae ethanol extract showed higher antioxidant activities in TBA value, and carbonyl value than other samples. In linoleic acid or eel oil, Hutgae extract was as superiorly effective in preventing peroxide generation of refrigerated eels as vitamin C 10 mM solution. In conclusion, pre-application of Hutgae water and ethanol (30°, Soju) extract on eels was proved to be competent in stopping peroxidation of eel in refrigeration.
        4,000원
        80.
        2022.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Since the Korean pronoun system does not specify gender indication, Korean speakers of English tend to have difficulties when they use English pronouns. This paper explores how absence of obligatory gender marking in Korean affects gender errors in the production of English. Gender pronoun errors made by Korean learners of English were analyzed using recordings of English conversations of seven Korean subjects. Findings of this study revealed that Korean English learners struggled with the use of gender pronouns due to differences in gender pronoun systems between Korean and English. Both gender-neutrality and pro-drop practices do not require Korean speakers to pay close attention to gender factors when using pronouns in their native language, resulting in native language interference. Considering that the Korean language lacks specific gender orientation in its usage of pronouns whereas English requires clear gender specification, findings of this study imply that native language gender concept can influence second language use.
        5,400원
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