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        검색결과 1,028

        21.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydrogen is considered as one of the most promising future energy carriers due to its noteworthy advantages of renewable and high calorific value. The long-term storage of liquid hydrogen with low heat leakage is essential for future deep space exploration. Because of low critical temperature and volatility, liquid hydrogen tank poses severe requirements to multi-layer insulation (MLI). In order to reduce heat leak into tank, vapor cooled shield (VCS) was set up to cool MLI by retrieving the heat of discharged cryogenic gas hydrogen. This paper presents an parametric study on insulation system in liquid hydrogen storage vessel with MLI and VCS. Thermal model was developed, and heat transfer analysis by varying VCS position was conducted. Temperature and heat flux distributions along time passing were derived, and effect of VCS position on insulation performance was investigated.
        4,000원
        22.
        2023.07 구독 인증기관·개인회원 무료
        The demand for knowledge transfer and experience sharing in terms of digital government and smart cities among partner countries has significantly increased. Digital government-related projects have been mainly proposed for the convenience of the system providers for the short-term or one-time instance without considering the mid-term to the long-term direction of digital government in partner countries. Due to this limitation, after the Knowledge Transfer projects are completed, the government partner countries that participated in the projects have examined the Knowledge Transfer projects and need to build improvement plans to promote the related project in efficient, effective, and sustainable ways with mid-term to long-term perspectives. This study focuses on the knowledge transfer projects in the digital government and smart cities that the Korean government and major public institutions carried out and analyses the status of digital knowledge transfer or official development assistance (ODA) projects from 2011 to 2020. In doing so, the study looked into establishing public sector systems such as digital government and smart cities and analysed the current status and research results of domestic and foreign studies related to assessment and diagnosis. Through this, major factors that determine the performance of digital government ODA were identified, and an analysis framework was derived for the analysis of existing cases of digital government knowledge transfer implementation.
        23.
        2023.07 구독 인증기관·개인회원 무료
        A typical consumer is exposed to more than 5,000 advertisements per day (Story 2015) by exposure to around 500 advertising messages before ending breakfast (Marshall, 2015), and it is impossible for consumers to remember most of the advertisement images and messages. Thus, one consistent yet not thoroughly investigated question for advertisers is how advertisers draw consumers' attention by differentiating their brand from competitors' brands. One suggestion from academia is making more "creative" advertising (Dahlén et al., 2008; Lehnert et al., 2014; Rosengren et al., 2013; Smith et al., 2008). However, it is still questionable the exact meaning of "advertising creativity," and the effects of creative advertising on consumer evaluation have not been fully investigated the effects of creativity in advertising evaluation by considering various boundary conditions. The objective of this research is to redefine advertising creativity, to understand how advertising creativity shapes consumers' evaluation, and how these effects are moderated by the different types of boundary conditions, such as industry category, by analyzing more than 100,000 advertising images and copies using a cutting-edge transfer learning technique. The results of the transfer learning algorithm indicate that both cognitive dimensions (e.g., novelty of image) and affective dimensions (e.g., awe and coolness) simultaneously affect the consumers' perception of the advertising creativity, and the current algorithm enables to detect of creative advertising image with 92% accuracy rate.
        24.
        2023.07 구독 인증기관·개인회원 무료
        Social media have emerged as one of the most important tools for firms to engage customers (e.g., Chandrasekaran et al., 2022; Cheng & Edwards, 2015; Lee et al., 2018; Wedel & Kannan, 2016). Within the tourism industry, scholars have investigated the role of social media communication in various contexts, such as online travel information search (Xiang & Gretzel, 2010), sharing travel experiences (So et al., 2018; Wang et al., 2022) and establishing positive customer relationships (Jamshidi et al., 2021). Insights into which social media content makes for generating positive engagement are, however, still largely based on marketers’ intuitions or focusing on message factors of social media posts such as message appeals (e.g., Wang & Lehto, 2020). It also often neglects the importance of the visual component of social media posts, and only a few research have investigated the effects of the image in social media on the travel industry (e.g., Fusté-Forné, 2022). The objective of this research is, therefore, to understand how textual features and image features generate user engagement in social media utilizing cutting-edge transfer learning techniques and to propose how these features should be customized to maximize user engagement for online travel shopping companies. We collect and analyze more than 10,000 Instagram posts from three online travel shopping companies, including Expedia, Priceline, and Kayak. The results from transfer learning algorithms utilizing 24 features, such as the number of people in the image, emotions expressed in the people in the image, hue, and RGB value, successfully predict the level of engagement measured by the number of likes and comments.
        25.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because multiple ovulation embryo transfer (MOET) in cattle includes several benefits such as wide spreading of genetically superior offspring for long distance, this biotechnological method has been widely applied to Hanwoo. When the recipients are not stayed close after embryo recovery from donor, the embryos are moved to other farms via several vehicles (car, train, and airplane). However, air travel induces lesser oxygen level, increased vibration, lower air pressure, higher noise, and increased exposure of cosmic radiation to living things than ground level. It was still unknown that fresh embryos obtained from multiple ovulation of Hanwoo could maintain their fertility after being transported via air plane, the present case report introduced a clinical case of MOET in Hanwoo after shipping fresh embryos via air transportation. The donor was multi-ovulated via follicle-stimulating hormone series of injection, which was followed by a gonadotrophin-releasing hormone injection and artificial insemination twice. The embryos were recovered by the uterine flushing, packed in ministraws, transported to recipients for 6 h including 1 h air flight, and then transferred to the synchronized recipients. During pregnancy diagnosis of early gestation period, 5 of 7 recipients (71.4%) presented no heat signs and showed fetal sacs with fluid under transrectal ultrasonography. After normal gestation period, all recipients naturally delivered healthy calves (male n = 2 and female n = 3) without abortion, stillbirth, and premature birth. The present case report indicated that transportation of fresh embryos for MOET via domestic flight in Korea did not affect to their fertility.
        4,000원
        26.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We used the measurement data derived from a proton transfer reaction time-offlight mass spectrometry (PTR-ToF-MS) to ascertain the source profile of volatile organic compounds (VOCs) from 4 major industrial classifications which showed the highest emissions from a total of 26 industrial classifications of A industrial complex. Methanol (MOH) was indicated as the highest VOC in the industrial classification of fabricated metal manufacture, and it was followed by dichloromethane (DM), ethanol (EN) and acetaldehyde (AAE). In the industrial classification of printing and recording media, the emission of ethylacetate (EA) and toluene (TOL) were the highest, and were followed by acetone (ACT), ethanol (EN) and acetic acid (AA). TOL, MOH, 2-butanol (MEK) and AAE were measured at high concentrations in the classification of rubber and plastic manufacture. In the classification of sewage, wastewater and manure treatment, TOL was the highest, and it was followed by MOH, H2S, and ethylbenzene (EBZ). In future studies, the source profiles for various industrial classifications which can provide scientific evidence must be completed, and then specified mitigation plans of VOCs for each industrial classification should be established.
        4,600원
        28.
        2023.05 구독 인증기관·개인회원 무료
        Radioactive Oxide is formed on the surface of the coolant pipe of the nuclear power plant. In order to remove the oxide film that is formed on the surfaces of the coolant pipe, chemical and physical decontamination technologies are used. The disadvantage of traditional technologies is that they produce secondary radioactive wastes. Therefore, in this study, the short-pulsed laser eco-friendly technology was used in order to reduce the production of secondary radioactive wastes. It was also used to minimize the damage that was caused to the base material and to remove the contaminated oxide film. The study was carried out using a Stainless steel 304 specimen that was coated with nickel-ferrite particles. Additionally, a transport robot was 3D modeled and manufactured in order to efficiently remove the oxide film from the coolant pipe of the nuclear power plant. The transport robot has a fixed laser head to move inside the horizontal and vertical pipes. The rotating laser head removes the contaminated oxide film on the inner surface of the coolant pipe. In the future, as a condition of the 1064nm short-pulsed laser ablation technique determined by basic analysis, we plan to analyze whether the transport robot is applicable to the radiation contamination site of the nuclear power plant.
        30.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        철도교량의 설계는 장기간에 걸쳐 수행되고 대규모의 부지를 대상으로 하기 때문에 다양한 환경적인 요인과 불확실성을 동반하게 된다. 이러한 연유로 초기 설계단계에서 충분히 검토하였더라도 설계변경이 종종 발생하고 있다. 특히 철도교량과 같은 대규모 시설 물의 설계변경은 많은 시간과 인력을 소모하며, 매번 모든 절차를 반복하는 것은 매우 비효율적이다. 본 연구에서는 딥러닝 알고리즘 중 전이학습을 통해 설계변경 전의 학습 결과를 활용하여 설계변경 후의 학습의 효율성을 향상시킬 수 있는 기법을 제안하였다. 분석 을 위해 기개발한 철도교량 딥러닝 기반 예측 시스템을 활용하여 시나리오들을 작성하고 데이터베이스를 구축하였다. 제안된 기법은 설계변경 전 기존 도메인에서 학습에 사용한 8,000개의 학습데이터 대비 새로운 도메인에서 1,000개의 데이터만을 학습하여 유사한 정확도를 나타내었고 보다 빠른 수렴속도를 가지는 것을 확인하였다.
        4,000원
        31.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We successfully synthesize water-dispersible CTAB-capped CdSe@ZnS quantum dots with the crystal size of the CdSe quantum dots controlled from green to orange colors. The quenching effect of Fe(DTC)3 is very efficient to turn off the emission light of quantum dots at four molar ratios of the CdSe quantum dots, that is, the effective covering the surface of quantum dots with Fe(DTC)3. However, the reaction with Fe(DTC)3 for more than 24 h is required to completely realize the quenching effect. The highly quenched quantum dots efficiently detect nitric oxide at nano-molar concentration of 110nM of NO with 34% of recovery of emission light intensity. We suggest that Fe(DTC)3-hybridized CdSe@ZnS quantum dots are an excellent fluorescence resonance energy transfer probe for the detection of nitric oxide in biological systems.
        4,000원
        32.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The sheep can be reproduced by natural mating as well as applied reproductive biotechnology, embryo transfer (ET). However, this method in sheep is influenced by several factors such as season, photoperiod, latitude, temperature, nutrition, and breed. In addition, there is still less research on assisted reproductive technologies in small ruminants, compared to other livestock species such as cattle and pigs. Because there has been a need for an optimization and a continuous improvement of ET techniques in small ruminants. the main objective of this study was to evaluate the conception rate obtained after ET in Mongolian sheep (Dorper breed). After embryo recover, code 1 and 2 embryos (morula or blastocyst stage) for ET in the present study were 63% (63/100) and 24% (24/100), respectively. Then Each single embryo was transferred to a synchronized recipient who prepared by estrous synchronization protocol with fluorogestone acetate-cloprostenol sodium. The results demonstrated that an average conception rate and lambing rate was 35.6% (31/87) and 33.3% (29/87), respectively. Further study is still necessary, but these results indicated that single embryo of Mongolian sheep with the present protocol was enough to conducting ET when the genetically superior sheep were necessary to be expanded.
        4,000원
        33.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the consumption of disinfectants have been increased by COVID-19 pandemic, the fate of the chemicals in aquatic food webs are still unclear. In order to understand the trophic transfer of the chemicals, the concentration of disinfectants including six benzalkonium chloride (BACs) and five didecyldimethylammonium chlorides (DDACs) were measured at the Geum (2020), Han (2021), and Yeongsan River (2021), before and after rainfall. The highest concentration of ΣBACs (mainly C12 and C14) and ΣDDACs (mainly C10 and C14) were observed in the Han River, followed by Yeongsan River, Geum River Estuary, and Gapcheon. After rainfalls, both concentration and detection frequency were decreased in all sites. Although the BAC and DDAC seems to be accumulated in organisms, they were bio-diluted rather than magnified in the aquatic food web with the biomagnification factor (BMF) of less than 1, trophic magnification slope (TMS) from - 0.236 to 0.001, and trophic magnification factor (TMF) from 0.85 to 1.01.
        4,600원
        34.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30°, from 30° to 180°, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5°. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.
        4,000원
        35.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 딥러닝의 전이학습 모델을 이용하여 항공사진과 토지이용현황도 간의 비교를 통해 토지이용현황의 변화를 탐지하는 방안을 마련하는 데 있다. 이러한 목적을 위해 딥러닝의 이미지 예측모델과 라스터와 벡터 자료를 비교하는 공간분석 기능을 이용하였다. 학습모델 구축을 통해 토지이용현황도의 상업지, 농지, 임지 및 수계에 대한 예측결과를 이용하여 토지이용의 변화를 탐지하는 방안을 제시하였다. 이러한 분석 방안은 라스터 형태의 최신 정보와 벡터 형태의 기존 자료와의 비교를 통해서 자료의 변화를 확인하는 방안으로 활용이 가능하다.
        4,000원
        36.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Among efforts to improve techniques for the chemical vapor deposition of large-area and high-quality graphene films on transition metal substrates, being able to reliably transfer these atomistic membranes onto the desired substrate is a critical step for various practical uses, such as graphene-based electronic and photonic devices. However, the most used approach, the wet etching transfer process based on the complete etching of metal substrates, remains a great challenge. This is mainly due to the inevitable damage to the graphene, unintentional contamination of the graphene layer, and increased production cost and time. Here, we report the systematic study of an H2 bubbling-assisted transfer technique for graphene films grown on Cu foils, which is nondestructive not only to the graphene film but also to the Cu substrate. Also, we demonstrate the origin of the graphene film tearing phenomenon induced by this H2 bubbling-assisted transfer process. This study reveals that inherent features are produced by rolling Cu foil, which cause a saw-like corrugation in the poly(methyl methacrylate) (PMMA)/graphene stack when it is transferred onto the target substrate after the Cu foil is dissolved. During the PMMA removal stage, the graphene tearing mainly appears at the apexes of the corrugated PMMA/graphene stack, due to weak adhesion to the target substrate. To address this, we have developed a modified heat-press-assisted transfer technique that has much better control of both tearing and the formation of residues in the transferred graphene films.
        4,000원
        37.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, we propose a mini-trench method, which involves using warm mix Guss mastic asphalt as a backfill material and an installation temperature of 160 ℃. The method is verified via a heat transfer analysis of a pavement using the finite element method. METHODS : First, the density, thermal conductivity, and specific heat required for heat transfer analysis were determined based on previous studies. Subsequently, the boundary conditions for convection and radiation to perform the heat transfer analysis were determined. The pavement temperature, which is the initial condition of the analysis, was determined based on the summer pavement temperature distribution using the temperature prediction program of the Korean pavement Research Program. Heat transfer analysis was performed by determining the temperature of the backfill material based on 160 °C and 200 °C for the heat load temperatures. The temperature change was observed on the backfill surface, and the temperature change of the conduit was observed directly. RESULTS : When the pavement surface temperature for traffic opening is 50 °C, the backfill thickness ranges from 50 to 250 mm, the warm mix Guss mastic asphalt requires 2 h to 5 h, 15 min until traffic opening, and the hot mix Guss mastic asphalt requires 2 h, 30 min to 6 h, 40 min until traffic opening. The limit temperature of the conduit evaluated based on KS C 8454 shows that the warm mix Guss mastic asphalt does not satisfy the standard when the backfill concrete cover is 50 mm thick, whereas the hot mix Guss mastic asphalt does not satisfy the standard when the concrete cover is 50 and 100 mm thick. CONCLUSIONS : The backfill depth of the mini-trench using warm mix Guss mastic asphalt as a backfill material should be less than 100 mm, considering the traffic opening time. Meanwhile, the thickness of the backfill concrete should be 100 mm or less.
        4,000원
        39.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we propose a dynamic stability prediction method for heavy vehicles based on Lateral Load Transfer Ratio. The key factors influencing vehicle roll motion are the vehicle's load, the position of the center of mass, the tread and the vehicle speed. Using these factors, we derive the lateral load transfer ratio (LTR) formula. In addition, we investigated LTR changes and vehicle rollover of heavy vehicles in various scenarios using TruckSim. As a result, the threshold value of the change rate of the LTR at which the vehicle rolls over was 0.68-0.72. Finally, we performed a numerical experiment to prevent rollover by calculating the optimal speed in the rollover situation.
        4,000원
        40.
        2022.10 구독 인증기관·개인회원 무료
        In 2004, in order to comply with UN Security Council Resolution 1540, the European Union (EU) came into force with Regulation 428/2009 for the export control of dual-use items, which has been working to prevent the proliferation of weapons of mass destruction (WMDs). In August 2021, it amended the EU 821/2021 to include mandating the introduction of ICPs for exporters in the member countries in order to strengthen controls over the transfer of tangible and intangible technologies. The main contents are as follows; 1) Mandatory introduction of Internal Compliance Program (ICP): Exporters within the EU countries should introduce a transaction review procedure through the ICP in consideration of their size and organization. 2) Export control on Cyber Surveillance Items to protect human rights: In order to protect human rights and comply with the obligations of international human rights law, EU countries should implement export controls on cyber-monitoring items exported from customs zones in the EU. Cyber surveillance items are specially designed to monitor, extract, collect or analyze data such as biometrics through intrusion of information and communication systems or deep packet hijacking. However, items used for purely commercial programs such as billing, marketing, quality service, user satisfaction or network security are excluded. 3) Expansion of the Catch-all system: EU countries should utilize the catch-all system to strengthen export controls on cyber-monitoring items, including dual-use items. 4) Strengthening control over the cloud: Exporters and EU countries should extend the scope of intangible technology transfer, such as electronic media, fax, and telephone, outside the EU’s customs territory, and apply export control regulations such as general or comprehensive licenses to cloud transmissions outside the EU territory. 5) Introduction of large-scale project authorization: To reduce the administrative burden on enterprises (especially small and medium-sized enterprises) and authorities when exporters with individual or collective licenses export to one or more specific end-users for the purpose of large scale projects, provided that they ensure the implementation of an appropriate level of export controls; EU countries may introduce large-scale project license systems in the form of general authorization. Recently, there is a possibility that the ROK would export its nuclear technologies including APR1400 to the EU member countries in the midst of the EU adoption of carbon-zero policy. In this paper, we have analyzed the EU export control regulations and suggested the future direction of nuclear export control programs in the ROK.
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