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        검색결과 1,597

        441.
        2018.07 구독 인증기관·개인회원 무료
        This research explored antecedents of stickiness of m-commerce sites, based on the push–pull–mooring (PPM) framework, which was developed to explain what leads people to move from one original location to another. In the current study, the stickiness of m-commerce sites was used as the opposite concept to switching. Therefore, pull effects refer to the positive factors which make consumers stick to an m-commerce site, while push effects refer to the negative factors which make consumers not stick with an m-commerce site. After reviewing the literature, responsiveness, ubiquity, enjoyment, and effectiveness were selected as the pull effects, while privacy concern and efficiency were selected as the push effects. The amount of money spent in specific mobile sites was considered as a mooring effect. According to the results of the structural equation modeling analysis, efficiency actually had a negative impact on stickiness of m-commerce sites. Also, a test of the mooring effect suggested that the negative impact of efficiency on stickiness of m-commerce sites was greater for people who spent more money in their mobile shopping compared to those who spent less. For both the high and low spending groups, responsiveness was the important pull effect as it was the strongest predictor of enjoyment for the low spending group and the strongest predictor of effectiveness for the high spending group (note that enjoyment and effectiveness had the strongest positive impacts on stickiness of m-commerce sites for the low and high spending groups, respectively.). Therefore, the fast response and feedback on m-commerce sites should increase consumers’ stickiness to these sites regardless of the amount consumers spend on these sites. On the other hand, the duration and retention of the low spending group of consumers were influenced by enjoyment the most.
        442.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        금번 연구를 통해 작은검정주머니나방속이 국내에서 처음 발견되어 보고한다. 작은검정주머니나방속 내 작은날개검정주머니나방에 대한 암컷 형태 특징, 채집지 정보 등을 포함한 이용가능한 모든 정보를 제공하였다. 또한 신속한 종 동정을 위한 DNA 바코드 정보를 작성하였다.
        4,000원
        443.
        2018.06 구독 인증기관 무료, 개인회원 유료
        The mesenchymal stem cells (MSCs) that reside in dental tissues hold a great potential for future applications in regenerative dentistry. In this study, we used human dental pulp cells, isolated from the molars (DPCs), in order to establish the organoid culture. DPCs were established after growing pulp cells in an MSC expansion media (MSC-EM). DPCs were subjected to organoid growth media (OGM) in comparison with human dental pulp stem cells (DPSCs). Inside the extracellular matrix in the OGM, the DPCs and DPSCs readily formed vessel-like structures, which were not observed in the MSC-EM. Immunocytochemistry analysis and flow cytometry analysis showed the elevated expression of CD31 in the DPCs and DPSCs cultured in the OGM. These results suggest endothelial cell-prone differentiation of the DPCs and DPSCs in organoid culture condition.
        4,000원
        447.
        2018.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We carry out a study of Sub-Millimeter Galaxies (SMGs) in the AKARI NEP-Deep field using the James Clerk Maxwell Telescope (JCMT) SCUBA-2 850 μm source catalog, released as part of the SCUBA-2 Cosmology Legacy Survey (S2CLS) program. The SCUBA-2 850 μm map has a root mean square (rms) noise of 1.2 mJy beam−1 and covers an area of 0.60 degree2. We find four SMGs which have counterparts to Herschel sources with spectroscopic redshifts in the literature. In addition, three dust obscured galaxies (DOGs) detected in Herschel bands are selected as a comparison sample. We derive IR luminosities of SMGs using the CIGALE code, which are similar to those of high redshift SMGs from previous studies. The contribution of AGN to the total IR luminosity in SMGs (2%–11%) is smaller than the lower limit for the one in DOGs (19%–35%), which is consistent with the expectation from the evolutionary scenario of massive galaxies. We search for SMGs in overdense regions as protocluster candidates and investigate four regions, including candidates around three DOGs. Finally, we argue that follow-up spectroscopic observation for the NEP-Deep field will provide crucial information to understand the role of SMGs in the evolution of massive galaxies.
        4,800원
        448.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ampelopsis brevipedunculata (Maxim.) Trautv., also known as porcelain berry, has been used for many years as herbal folk medicine to treat liver diseases. This study was conducted to assess the influence of various factors on the rooting of hardwood stem cuttings of this plant species, collected from Jeju Island (Korea). Three experiments were conducted: (1) Stems of three diameters (≤ 4.5, > 4.5 – < 6.5, or ≥ 6.5 mm), (2) four types of rooting media [rockwool cubes, perlite, peat moss + perlite (3:1, v/v), or vermiculite] and (3) indole-3-butyric acid (IBA) at four treatment concentrations (0, 100, 200, or 400 mg·L-1). For the IBA concentration experiments, cuttings of the various diameters were inserted to a depth of 2 cm in a commercial propagation medium in 72-cell plug trays. The planted stem cuttings were initially placed on a fog bench for 16 days at 95% ± 5% relative humidity at a temperature of 25°C ± 3°C under 95% shade. The stem cuttings were then transferred to a greenhouse bench under ambient light and fed a nutrient solution on a daily basis for 2 weeks. Among the tested stem diameters, cuttings with a stem diameter ≥ 6.5 mm produced the largest stem diameter (2.6 mm) of new shoot, but without root growth. Initial stem diameter significantly affected the length of the new shoot, and the longest shoot length (67.8 mm) was observed in cuttings with an initial stem diameter of ≥ 6.5 mm. Cuttings inserted in vermiculite produced the largest diameter of new shoot (2.4 mm), whereas cuttings grown in rockwool cubes produced the shortest, stem diameter of new shoot growth (1.9 mm). No significant differences (p ≤ 0.05) were observed in the length of new shoot growth among the various rooting media and IBA concentrations. Furthermore, all tested IBA concentrations failed to induce rooting. Collectively, these results suggest that porcelain berry cuttings with an initial diameter of ≥ 6.5 mm have higher survival and bud break, but they did not produce rooting. Further studies are needed to optimize the protocol for the rooting of hardwood stem cuttings of A. brevipedunculata (Maxim.) Trautv.
        4,000원
        452.
        2018.05 구독 인증기관·개인회원 무료
        In the United States and Europe, new environmentally friendly asphalt pavement has been researched as an alternative to traditional hot asphalt pavement. After the Paris Convention of 2015, policies should be found to reduce carbon dioxide. In the field of asphalt pavement, new methods are needed to reduce carbon dioxide from the traditional hot asphalt pavement. In Korea, waste asphalt is growing and natural aggregate is running dry. So the government is implementing policies to increase the use of waste resources. So, it created a new asphalt pavement method to reduce CO2 and use waste asphalt. It is a cold recycled asphalt pavement. Emulsified asphalt has a balance of dispersibility, stability, and adhesive between water, aggregates, and asphalt. But, the physical properties of emulsified asphalt can be degraded compared to traditional hot asphalt pavement. So there are limitations in actual use. The study compared the softening point, elastic recovery, and penetration properties of asphalt mix compounds by using latex in emulsified asphalt. In particular, cations latex was used for the emulsified asphalt, which could further improve the physical properties.
        453.
        2018.05 구독 인증기관·개인회원 무료
        To be better fit for highways, pavement systems are required to provide comfortable and safe driving and be structurally durable. Composite pavements can be an effective option as they are more durable by placing a high functional asphalt overlay on a rigid concrete base layer. In order to apply a composite pavement system to the field, it is necessary not only to develop technologies that prevent reflecting crack and deterioration of the base layer, but also to improve bonding performance of materials and ensure structural performance as a pavement system against traffic loading. In advanced countries like Japan, USA and Europe, high-functional composite pavement systems are being put into practice across new highway networks. In this study, we evaluated structural performance (rutting, reflecting crack, and deflection) by applying traffic loads of actual highways through an accelerated pavement tester (APT) of a composite pavement section made up of a quiet porous surface laid over a water-proofing layer, a continuously reinforced concrete base, and a lean concrete sub-base layer, which was developed with new pavement methods used for each layer prior to field application. The APT specimen was constructed with paving materials and equipment actually used on site in the same dimensions (W3.5m*L14m*H2m) as actual highway sections in Korea, and 3-axle double-wheel heavy load (45ton) cart type KALES(Korean Accelerated Loading and Environmental Simulator) traveling on the specimen in both directions was used to simulate traffic loading. After applying around 8,574,000 ESALs of traffic loads, no reflecting crack occurred on the asphalt surface of the composite pavement, without surface distress except for rutting. In order to examine what causes rutting of pavements, we surveyed thickness of pavements by layer and measured asphalt density.
        454.
        2018.05 구독 인증기관·개인회원 무료
        In recent years, pavement distresses have been caused by diverse factors such as spalling, deterioration of repaired sections, blow-up, and alkali aggregate reaction due to changing climate environment of a concrete pavement and its construction and maintenance conditions (supply of materials, increase in use of de-icers, etc,). As a leading repair method for deteriorated concrete pavements, partial-depth repair is implemented in accordance with guidelines of material properties for joints of a concrete pavement and field application evaluation systems, but still some of the repaired sections become deteriorated again at an early stage due to poor construction quality and failure of response to environmental impacts. Distresses that can be corrected with partial-depth repairs are largely divided into those of repair materials and of the existing pavement bonded to repair materials, and combined distress of repair materials and the existing pavement. Although re-repair methods should be different by distress type and scale than conventional pavement repair methods, appropriate repair methods and guidance for re-repairs have not been in place so far, and therefore currently, re-repair practices follow the existing manual of partial depth repairs. Therefore, this study evaluated concrete bond characteristics by removing method and repair scope for an experimental section of frequently distressed pavements to determine a re-repair scope and method for deteriorated partial depth repair sections of concrete pavement, the number of which has increased over time.
        455.
        2018.05 구독 인증기관·개인회원 무료
        Composite pavements are constructed by placing a high functional asphalt surface layer on a high performance concrete rigid base layer and provide a more durable, high functional surface to road users. Service life of composite pavements is dependent on the bonding performance of the lower rigid base and the flexible surface layer. Accordingly, it is necessary to place an impermeability layer between the functional surface layer and the rigid base to enhance bonding performance and to prevent moisture penetration into the rigid base and deterioration of pavement. In order to use optimal composite pavement sections, two types were applied to impermeability layer: highly impermeable water-tight SMA and mastic asphalt currently in use. APT (Accelerated Pavement Testing) and experimental construction were carried out to evaluate bond strengths between the rigid base and the impermeability layer depending on the type of impermeability layers. Composite pavement sections for the APT had a 22 cm concrete rigid base layer and a 5cm functional surface, as well as either 5cm of SMA impermeability layer and 5cm of mastic layer. After applying around 8,574,000 ESALs, pull-off test was conducted, which showed that the mastic section outperformed the SMA section. In the experimental construction, three types of rigid base layers, JCP (Jointed Concrete Pavement), CRCP (Continuously Reinforced Concrete Pavement), and RCCP (Roller Compacted Concrete Pavement), were used for composite pavement sections, and as in the APT, two types of impermeability layers, SMA and mastic, were used per rigid base layer of new and deteriorated concrete pavement. Therefore, seven composite pavement sections in total were constructed. We measured the bond strength over one year or so following the construction of these composite pavement sections and found that regardless of the type of rigid base layer and whether it was new or not, those sections with a mastic impermeability layer had high bond strengths.
        456.
        2018.05 구독 인증기관·개인회원 무료
        In Korea, concrete pavements were first applied to highways in 1981 and as a result of continued increase in length over the past years, 2,592 km of concrete pavement network is currently in service, of which 1,399 km(54%) of concrete pavements is 10 years or older, and 233km(9%) is 20 years or older. The length of concrete pavement sections nationwide has been steadily on the rise every year (EXTRI, 2017). Approximately 54% of current concrete pavement highway network will reach the service life limit in 2025 which means around 660 billion won is needed for future pavement repair project (EXTRI, 2017). Given that concrete pavements beyond design life still have a remaining service life, it is economically advantageous to repair them before reconstruction. Asphalt overlays are a major repair method for older concrete pavements. Depending on the concrete pavement condition, thickness and mixture of asphalt overlays are determined. Service life of asphalt overlays varies by the presence, time and size of cracks in existing concrete pavements and reflecting crack at joints. Temperature change of concrete pavement is among the major reaction parameters of reflecting crack. Reflecting crack develops when asphalt bottom-up cracking by longitudinal shrinkage and expansion due to temperature change of the concrete base layer, top-down cracking by temperature difference between top and bottom of concrete, and shear stress by traffic loading are combined (Baek, 2010). Crack and joint behaviors of concrete pavement vary between the base layer and the concrete surface of composite pavement system, and different conductivity by mixture and thickness of asphalt overlay leads to temperature change of concrete base course. This study measured temperatures of each layer of diverse composite pavements in place on site and analyzed differences in temperature change of concrete base layer depending on mixture and thickness of asphalt overlays. Overlay thickness parameters were 5cm and 10cm, two values most widely used, while mixture parameters were SMA and porous asphalt. Based on temperature change of concrete surface, this study also evaluated the difference of temperature change in concrete base layer with an asphalt overlay on top. Findings from this study are expected to be utilized for studies on mechanism and modeling of reflecting crack in old concrete pavements with asphalt overlays.
        457.
        2018.05 구독 인증기관·개인회원 무료
        In this study, eye movements of drivers on expressway ramps were comprehensively investigated using raw data from driving simulator and eye tracker(MyGaze) deducted though the previous study. Based on the literature review, several parameters including number of fixations, fixation time, horizontal & vertical eye movements, and gaze position were selected. With them, eye movements of older drivers and young drivers were compared and investigated. Average fixation time of older drivers is shorter and tend to focus more on the inside road edge for both left and right turning ramps comparing young drivers. Also, they tend to look wider at right turning ramp. All driver’s fixation points were spread along the inside road edge for both left and right turning ramps. Currently, road delineating facilities are installed on the side where centrifugal force is applied. However, considering the result, it should be installed where centripetal force is applied. In addition, road line marking management should be more taken care of. For future study, vehicle’s speed is also in need of consideration with eye movement.
        458.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined images typical to this city and explored ways to develop cultural products using these images. Researchers reviewed literature about fashion cultural products and related previous research, and then conducted a closed-ended survey to analyze universal fashion preferences. For the examination material, such a way was used as information data base and network review inside and outside the country, dissertation screen, and published media including separate volumes. The following are considering points in the developing process. First, the study identified design, color, price, practicality and quality as factors that should be taken into consideration when using the image of Gangneung. In particular, it determined that the image needs to reflect a modern sensibility while maximizing its representation of local culture. Second, Gangneung’s symbolic image should incorporate the sea, Gyeongpo, and coffee. In other words, the sea, Gyeongpo, and coffee should receive top symbolic priority. Third, from a development perspective, the most appropriate items for displaying the image include t-shirts, keychains, umbrellas, or other accessories, since these items are easily available in terms of price. In sum, this study highlighted the necessity of reconsidering Gangneung’s currents ymbolic image, suggesting that a new image should be developed. Developing a typical fashion cultural product image will enrich Gangneung’s cultural industry and the distribution of newly designed products will improve the localeconomy.
        5,200원
        459.
        2018.04 구독 인증기관·개인회원 무료
        Gryllus bimaculatus is one of many cricket species known as field crickets. Also known as the African or Mediterranean field cricket or as the two-spotted cricket, it can be discriminated from other Gryllus species by the two dot-like marks on the base of its wings. G.bimaculatus is a subtropical insect and widely distributed from Africa to south Asia. After into the country, The species are popular for use as a food source for insectivorous animals like spiders and reptiles kept as pets. In 2016, G.bimaculatus was approved as a general food ingredient by Korean Ministry of Food and Drug Safety. However, domestic research on G.bimaculatus is still in its study is beginning stages. G.bimaculatus is possible species to year-round rearing without storage condition. but The aim of the present study prepares for in case of problems such as breeding space, labor cost etc. In the laboratory condition at 28±2℃ and 50% relative humidity under 10h light, 12h dark photoperiod, Adult crickets oviposit at soaked flower foam for 24 hours. The experiment on the hatching of the eggs showed that eggs could be stocked at 16℃ for 10 days with 7 day pre-period after laying, representing 85% hatchability.
        460.
        2018.04 구독 인증기관·개인회원 무료
        풀무치(Locusta migratoria)는 메뚜기과에 속하는 곤충으로 70% 이상의 단백질을 함유하고 있어 식사료용 곤충으로 이용 가능성이 높다. 그러나 풀무치의 대량생산을 위한 연중사육 관련 연구는 미흡하여 사육방법 정립, 먹이원 선발 등이 필요하다. 본 연구에서는 풀무치의 연중사육을 위한 방법으로 사육밀도에 따른 생육 특성과 최적 산란처를 찾기 위해 상토, 오아시스 등을 이용하여 산란 특성을 조사하였다. 풀무치의 생육 온도는 28℃, 습도는 65% 내외로 유지하고 처리구별 생존율, 탈피횟수, 크기, 무게 등을 측정하였다. 사육밀도별 약충 기간은 32일 소요되었고, 생존율은 82~90 %였으며, 성충 기간은 110~120일 소요되었다. 산란처별 난괴 길이는 33~49mm였으며, 부화 후 생존율을 72~82%였다.