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        검색결과 2,998

        2721.
        2013.07 서비스 종료(열람 제한)
        The high temperature due to climate change may result in the intensification of several drought and heat stress on crops including potato. These abiotic stress affect on potato development staages; sprout development, tuber initiation and maturation. Potatoes need moderate amounts of nitrogen and cool night for good tuber growth. Especially, high temperature in soil will delay tuber initiation and induce malformation. Therefore, to identify quickly heat tolerant lines and breeding potato lines adapt to high temperature in the field are needed. The objectives of this study were as follows; To apply in vitro screening method for identifying potato lines adapted to high temperature conditions. To verify these results under field assays carried out under natural high temperature field conditions. We used in vitro screening methods with breeding lines from Intranational Potato Center(CIP) under three temperature regime, 18℃, 25℃ and 30℃. All breeding liens had some genotype that produced microtubers at 18℃ and 25℃, with a clear tendency for lower percentage of tuberization at the high temperature. To verify in vitro screening methods for heat tolerance lines, we carried out natural high temperature filed evaluation at Tacna, La Molina and Sanramon in Peru. The results of both the in vitro test and the field assay showed clear relationship and similar expression of tuberization percentage. This finding supports the use of the in vitro assay as a rapid screening methods that represents performance at the field level. But the correlation between performance of the breeding lines under the in vitro and field condions was low. This could be due to differential response to breeding lines to characteristics of the field environment, such as soil salinity, drought, which were not represented in the in vitro assay.
        2722.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        Morus Folium (Sang-yeop in Korean) is one of the most important Oriental medicinal plants. In Korea, both M. alba and M. cathayana are regarded as the botanical sources for Morus Folium. In order to discriminate M. alba and M. cathayana from their adulterant, M. tricuspidata, mitochondrial NADH dehydrogenase subunit 7 (nad7) intron 2 region was targeted for molecular analysis with universal primers. DNA polymorphisms, including SNP sites, insertions, and deletions, were detected among these three species sequencing data. Based on these DNA polymorphisms, specific primers were designed for the three species respectively. Multiplex PCR was conducted for molecular authentication of M. alba, M. cathayana, and M. tricuspidata with specific primers. The present results indicate that it is possible to identify Morus Folium from its adulterant using mitochondrial nad7 intron 2 region. The established multiplex-PCR system was proved to be effective for identification of Morus Folium. The results indicate that mitochondrial introns can be used for inter-specific polymorphic study, and the described method can be applied for molecular identification of medicinal materials.
        2723.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        The research concerned of the regeneration of plants from embryos obtained from anther cultures of ginseng (Panax ginseng C. A. Meyer). The aim was to determine the influence of the regeneration medium on the efficiency of the regeneration process. We conducted to determine the optimum conditions such as cold pretreatment, plant growth regulators and carbon sources on anther culture of P. ginseng. Highest callus formation rate was obtained when flower buds pretreated at 4℃ for 1 day. Among the treated growth regulators with various degrees of concentration in Murashige and Skoog's (MS) medium, 4.53 μm of 2.4-dichlorophenoxyacetic acid and 4.44 μm of 6-benzylaminopurine gives the most responsive callus with the frequency of 73.89% and 129.53 g of fresh weight. When we used 3-9% of sucrose and maltose among the different kinds and various concentrations of carbohydrates, callus was formed highest 67.29% in the medium with 3% of sucrose. Shoots induced from callus supplemented with 28.9 μm of gibberellic acid and rooted in Gamborg's B5 medium supplemented with 14.7 μm of indole-3-butyric acid.
        2724.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        Korean ginseng has been used for thousands of years as an important medicinal plant. Lime-Bordeaux mixture (LBM) was made with copper sulfate and quicklime, which was sprayed instead of pesticides in ginseng field. Net photosynthesis (PN) was compared between Treatment and Non-treatment of LBM in 3 Year Old Ginseng. PN in control plot recorded 2.94μmol (CO2) m-2s-1 at the first day of experiment, which was similar until the last day of experiment. However, The PN in LBM recorded 2.23μmol (CO2) m-2s-1, which was lower than that in control plot. As time goes by, The PN in LBM was gradually increased up to 3.21μmol (CO2) m-2s-1 and finally, it was similar with that in control plot at 7th day as a 3.20μmol (CO2) m-2s-1).
        2729.
        2013.03 KCI 등재 서비스 종료(열람 제한)
        Purpose - objective of this research is to investigate individual, organizational and environmental factors influence tacit knowledge sharing among healthcare professionals. The transmission of Tacit Knowledge is crucial for organizations to ensure that TK will be passed throughout organization, rather than stored in single employee. Research design, data, and methodology - In this study investigate organizational, individual and environmental factors that influence on TK sharing. To test hypothesizes, the survey method was chosen. Sample size was 100 but 74% of questioners returned. Results - The main findings of this research are related to influence of personal, social cultural and behavioral factors on tacit knowledge sharing. According to extracted data all factors have influence on tacit knowledge sharing except Emotional stability that was found to be negatively related to tacit knowledge sharing. That may means anxiety and stress level of workplace applies negative enhance on tacit knowledge sharing. And finally results show that social environment, team oriented culture and organizational commitment have strongest influences on tacit knowledge sharing. Conclusion - the findings of this study shows that personal, social cultural and behavioral factors influence on tacit knowledge sharing. And also indicates that, social and organizational factors enhance strongly on tacit knowledge sharing.
        2730.
        2013.03 KCI 등재 서비스 종료(열람 제한)
        Purpose - Labor productivity is extremely important to the profitability and competitive advantage of organizations that provide services to customers, such as banks. This study investigates the factors driving labor productivity in Iran’s Melli Bank. Research design, data, methodology - Five managerial, psychosocial, cultural, and individual factors are identified and their relative importance for labor productivity prioritized using AHP. The required data are then collected through a questionnaire designed for a pairwise comparison of the driving factors of labor productivity and their subcategories. Results - The study outcomes reveal that the managerial and individual factors are the most important. Specifically, the most important factors in increasing labor productivity in the branches of Melli Bank are having a competent supervisor, promotion opportunities, fair working conditions, conscientiousness, the right tools, and a correspondence between skills and work. Conclusions - Implementing AHP using Expert Choice software revealed that, among the driving factors of labor productivity (i.e., managerial, psychosocial, cultural, environmental, and personal), managerial factors were considered the most important by the respondents.
        2731.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We statistically investigated the properties of low-latitude Pi2 pulsations using Bohyun (BOH, Mlat = 29.8°, L = 1.35) ground magnetometer data in 2008. For this 1-year interval, 582 Pi2 events were identified when BOH was in the nightside from 1800 to 0600 local times. We found the following Pi2 characteristics. (1) The occurrence distribution of Pi2s is relatively constant in local times. (2) The Pi2 frequency varies in local times. That is, Pi2 pulsations in postmidnight sector had higher frequency than in premidnight sector. (3) Pi2 power in premidnight sector is stronger than in postmidnight sector. (4) Pi2 frequency has positive correlation with solar wind speed and AE index. (5) Pi2 power has not a clear correlation with solar wind parameters. This indicates that Pi2 power is not controlled by external sources. (6) It is found that the most probable-time between Pi2 onsets is Δt ~ 37.5 min: This is interpreted to be the period between Pi2 pulsations when they occur cyclically. We suggest that Δt ~ 37.5 min is the occurrence rate of reconnection of open field lines in the tail lobe.
        2732.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The use of generating functions for solving optimal rendezvous problems has an advantage in the sense that it does not require one to guess and iterate the initial costate. This paper presents how to apply generating functions to analyze spacecraft optimal reconfiguration between projected circular orbits. The series-based solution obtained by using generating functions demonstrates excellent convergence and approximation to the nonlinear reference solution obtained from a numerical shooting method. These favorable properties are expected to hold for analyzing optimal formation reconfiguration under perturbations and non-circular reference orbits.
        2733.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        A collision-free formation reconfiguration trajectory subject to the linearized Hill’s dynamics of relative motion is analytically developed by extending an algorithm for gravity-free space. Based on the initial solution without collision avoidance constraints, the final solution to minimize the designated performance index and avoid collision is found, based on a gradient method. Simple simulations confirm that satellites reconfigure their positions along the safe trajectories, while trying to spend minimum energies. The algorithm is applicable to wide range of formation flying under the Hill’s dynamics.
        2734.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        An integrated orbit and attitude control algorithm for satellite formation flying was developed, and an integrated orbit and attitude software-in-the-loop (SIL) simulator was also developed to test and verify the integrated control algorithm. The integrated algorithm includes state-dependent Riccati equation (SDRE) control algorithm and PD feedback control algorithm as orbit and attitude controller respectively and configures the two algorithms with an integrating effect. The integrated SIL simulator largely comprises an orbit SIL simulator for orbit determination and control, and attitude SIL simulator for attitude determination and control. The two SIL simulators were designed considering the performance and characteristics of related hardware-in-the-loop (HIL) simulators and were combined into the integrated SIL simulator. To verify the developed integrated SIL simulator with the integrated control algorithm, an orbit simulation and integrated orbit and attitude simulation were performed for a formation reconfiguration scenario using the orbit SIL simulator and the integrated SIL simulator, respectively. Then, the two simulation results were compared and analyzed with each other. As a result, the user satellite in both simulations achieved successful formation reconfiguration, and the results of the integrated simulation were closer to those of actual satellite than the orbit simulation. The integrated orbit and attitude control algorithm verified in this study enables us to perform more realistic orbit control for satellite formation flying. In addition, the integrated orbit and attitude SIL simulator is able to provide the environment of easy test and verification not only for the existing diverse orbit or attitude control algorithms but also for integrated orbit and attitude control algorithms.
        2735.
        2012.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The problem of spacecraft attitude control is solved using an adaptive neuro-fuzzy inference system (ANFIS). An ANFIS produces a control signal for one of the three axes of a spacecraft’s body frame, so in total three ANFISs are constructed for 3-axis attitude control. The fuzzy inference system of the ANFIS is initialized using a subtractive clustering method. The ANFIS is trained by a hybrid learning algorithm using the data obtained from attitude control simulations using state-dependent Riccati equation controller. The training data set for each axis is composed of state errors for 3 axes (roll, pitch, and yaw) and a control signal for one of the 3 axes. The stability region of the ANFIS controller is estimated numerically based on Lyapunov stability theory using a numerical method to calculate Jacobian matrix. To measure the performance of the ANFIS controller, root mean square error and correlation factor are used as performance indicators. The performance is tested on two ANFIS controllers trained in different conditions. The test results show that the performance indicators are proper in the sense that the ANFIS controller with the larger stability region provides better performance according to the performance indicators.
        2736.
        2012.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We made a study on real-time determination method for relative position using the laser-measured distance data between satellites. We numerically performed the determination of relative position in accordance with extended Kalman filter algorithm using the vectors obtained through nonlinear equation of relative motion, laser simulator for distance measurement, and attitude determination of chief satellite. Because the spherical parameters of relative distance and direction are used, there occur some changes in precision depending on changes in relative distance when determining the relative position. As a result of simulation, it was possible to determine the relative position with several millimeter-level errors at a distance of 10 km, and sub-millimeter level errors at a distance of 1 km. In addition, we performed the determination of relative position assuming the case that global positioning system data was not received for long hours to see the impact of determination of chief satellite orbit on the determination of relative position. The determination of precise relative position at a long distance carried out in this study can be used for scientific mission using the satellite formation flying.
        2737.
        2012.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth’s geomagnetic filed by space weather, we use the international quiet days’ data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components’ quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation’s amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth’s atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.
        2738.
        2012.10 KCI 등재 서비스 종료(열람 제한)
        Headwaters initiate material export to downstream environments. A nested headwater study examined the flux of dissolved constituents and water from a perennial stream and four ephemeral/intermittent streams in the Upper Gulf Coastal Plain of Mississippi. Water was collected during storm and baseflow conditions. Multiple linear regression was used to model constituent concentration and calculate flux. Event was the major source of water discharged from the ephemeral and intermittent streams however, baseflow was the major source for water discharged by the perennial stream during events. The perennial stream had an area weighted average yields of 10.1, 0.01, 1.03, 0.65 kg/ha/yr of DON (dissolved organic nitrogen), NO3 --N, NH4 +-N and PO4 -3, respectively while large variabilities existed between the ephemeral and intermittent streams. These findings highlight the importance of headwaters in protecting the low order drainage basins as a key to water quality within perennial streams.
        2739.
        2012.07 서비스 종료(열람 제한)
        Phosphorus (P) is an important structural component and plays critical roles in the process of energy transfer and signal transduction. Effect of low P on carbohydrate metabolism was investigated at the transcription level via transcriptome analysis using the rice 60K oligonucleotide DNA microarrays. Two-week-old rice seedlings were grown under a low (32 μM) or high (320 μM) P condition for two weeks and leaves from the seedlings were used for transcriptome analysis. Expression of genes involved in carbohydrate metabolic pathways (eg. glycolysis, sucrose degradation and starch synthesis and degradation) was most significantly affected under low P. Under low P, most genes involved in glycolysis were intensively down-regulated, genes of starch biosynthesis and degradation pathway were up- or down-regulated, and many genes involved in sucrose biosynthesis were intensively up-regulated. In leaves under low P, glucose and pyruvate levels decreased, but sucrose and starch levels increased. These results suggest that carbohydrate metabolism is adjusted primarily through comprehensive transcriptional modulation of genes involved in the carbohydrate metabolic super-pathway.
        2740.
        2012.07 서비스 종료(열람 제한)
        ’Dahan’ (Avena sativa L.), a winter oat for forage use, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, National Institute of Crop Science (NICS), RDA in 2011. It was derived from an original cross between the F1 hybrid of ‘Sprinter’ and ‘73625’ and ‘Gwiri26’ (PA7507-37). Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Suwon. A line, ‘SO99027-GB-B-113-4-4-3’, was selected for cold tolerance and good agronomic characteristics and designated as a line name of ‘Gwiri75’. The line ‘Gwiri75’ was subsequently evaluated for cold tolerance, earliness, and forage yield in four different locations, Yesan, Iksan, Kimjae, and Jeju, from 2009 to 2011 and finally named as ‘Dahan’. Over 3 years, the average forage dry matter yield of ‘Dahan’ harvested at milk-ripe stage was 15.6 MT ha-1, compared with 14.1 MT ha-1 of check cultivar ‘Samhan’. Though similar in heading date to the check cultivar, ‘Dahan’ had tall plant length and lodging resistance. The feed value of ‘Dahan’ was superior to the check cultivar in percent total digestible nutrients (TDN) and TDN yield per ha. ‘Dahan’ is recommended primarily for winter planting use in the areas where daily minimum mean temperatures are averaged higher than -6 ℃ in January, and excluded in mountain area where frost damage is presumable.