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        검색결과 13

        1.
        2016.10 구독 인증기관 무료, 개인회원 유료
        Recently, the interest in the educational robotics has grown greatly, but few studies have been conducted in this field. This study intended to investigate the trend of usage robotics in education during the period of 2001-2014 while analyzing 133 research papers to find the answers to the following questions. First, what is the general research trend of utilizing robotics in education? Second, what are the most recent issues and challenges of robotics in education? Publications have been analyzed using quantitative analysis and cross-tabulation. All gathered articles have been categorized and analyzed under twelve categories. Furthermore, seven categories have been cross-tabulated with other categories. Overall findings present that there are a significant amount of publications on higher and secondary education. Articles on early education and teachers training have started to become more apparent lately. It has also been noticed that robotics generally is seen as an extracurricular activity. Among educational robots, ‘robot kit’ type was one of the highly utilized, especially LEGO Mindstorms robot kit. The main objective of most analyzed articles is the experience of a course curriculum. Results of the study show that there are three main issues and challenges of robotics in education. First, there is a lack of quantitative research on the impact of robotics in education. Second is an absence of well-defined curriculum for target audience. Third is the narrow use of robotics in education. The study also present recommendations for future research.
        4,900원
        2.
        2016.07 구독 인증기관·개인회원 무료
        Substantial knowledge about how electronic word of mouth (eWOM) relates to influentials, or, individuals who either intentionally or unintentionally have a great impact on the network, is lacking because influence patterns are hardly quantifiable when human and societal components are not deeply understood. The eWOM networks in social media platforms drive the theoretical and practical progress of the social structure of eWOM and the social role of influentials. The purpose of this study is to explore the diffusion of eWOM in a Twitter network by drawing from the Diffusion of Innovation theory in conjunction with Social Network Analysis (SNA) approach. Through a large amount of data collected from Twitter regarding the terrorist attack in Paris on November 13, 2015, this study examined the social structure of eWOM network groups and identifies the social role of influential users in the network of #prayforparis. To identify influentials of eWOM in Twitter networks, SNA was conducted with NodeXL, which is an Excel add-in network analysis software. The Twitter data set was uploaded at 11 am, on November 17, 2015 by applying hashtag prayforparis through Twitter Search Network feature of NodeXL. A total of 19,592 tweets (vertices) were downloaded with a total of 20,297 edges (relations between vertices). “Justin Bieber” was identified as the most influential and dominant user in the network of #prayforparis because he has the highest in-degree (4,196) and highest betweenness centrality (51,772,745.861). Justin Bieber lost one of his friends in the terrorist attack, and his tweet about the sadness from the loss was retweeted more than 50,000 times and received 77,000 likes. Throughout the network, top word pairs respectively repeated more than 4,000 times were “thomas, prayforparis,” “rt, justinebieber,” “rip, thomas,” and “justinbiber, rip.” “Ally Brook” and “Louis Tomlin” ranked 3rd and 5th respectively with the highest betweenness centrality also demonstrated the celebrity power in the eWOM network of #prayforparis. While the three celebrities as dominant influentials were prominent in the Twitter network of #prayforparis, the social roles of fans were also acknowledged. The celebrities’ fans and fan sites have constantly diffused the celebrities’ posts by retweeting and by mentioning every tweet posted by the celebrities that they support. Without the celebrities and their fans, the #prayforparis network would have depicted a completely different style of diffusion of eWOM. The study confirmed social role of fans that constantly presented idiosyncratic manners by identifying and by linking to the public figure. The distinctive characteristics of the fans also enabled identifying the social role of the celebrity while spreading the new ideas with hashtag. The celebrity played a key role as an information hub even in a network of socio-political events such as the #prayforparis Twitter network. Thus, identified overwhelming influence of the celebrities in the eWOM network extends the areas of marketing choices and applicable strategies with celebrities.
        8.
        2012.06 구독 인증기관·개인회원 무료
        The aim of this study was to examine the effect of acteoside (the cyclin-dependent kinase inhibitor) on the SCNT efficiency with adult fibroblasts in dog. Canine adult fibroblasts were obtained from muscle and cell cycle of fibroblasts was synchronized by culturing to confluency, serum starvation and treating with 30 μM acteoside for 48 h. Cell cycle stages, cell cytotoxicity (apoptosis) and, prduction of reactive oxygen species (ROS) were analyzed using flow cytometry. The canine cells, prepared by confluent-cell culture or treating with 30 μM acteoside for 48 h, were injected into enucleated in vivo matured oocytes, the couplets were electrical fused and activated by calcium ionomycin. SCNT embryos using acteoside-treated fibroblasts were surgically transferred into oviducts of estrus cycle synchronized recipient dogs. In cell cycle synchronization (G0/G1), there was no significant difference between serum starvations (83.9%) and acteoside treated groups (81.3%) that were higher than confluent group (78.5%). In production of apoptosis, confluent and acteoside treated groups (4.3 and 4.5%, respectively) were generated less than serum starvation group (21.8%). In case of ROS, serum starvation group was induced a significantly higher than other groups. After synchronization of the donor cell cycle, either confluent or acteoside treated, cells were placed with enucleated in vivo-matured dog oocytes, fused by electric stimulation, activated, and transferred into naturally estrus-synchronized surrogates. Fusion and cleavage rate of acteoside treated group were 64.1 and 41.5%, which were higher than those of confluent group (53.9 and 20.6%, respectively). The reconstructed embryo development rates to 4-cell and 8-cell in acteoside treated group were 29.5 and 14.8%, respectively, while confluent group showed 11.1 and 3.2%, respectively. Total 54 SCNT embryos using acteoside-treated fibroblasts were transferred into oviducts of 2 recipient dogs and one recipient finally delivered one puppy, whereas din`t detected pregnancy on transfer of cloned embryos reconstructed with confluent cells in 6 surrogate dogs. In conclusion, the results of the current study demonstrated that canine fibroblasts could be successfully arrested at the G0/G1 stage with reduced the formation of ROS and apoptosis after acteoside treatment. This results may contribute to improve the effi-ciency of canine SCNT. * This research was supported by iPET (Grants 110056-3), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
        9.
        2012.06 구독 인증기관·개인회원 무료
        Acteoside acts as an anti-oxidative activity and anti-apoptosis in the cells. But, it has been not studied on maturation and development of porcine oocytes. The aims of the present study were to examine the effects of acteoside on the morphological progress of meiosis, developmental competence, and ROS in porcine oocytes. Oocytes were matured in tissue culture medium-199, supplemented with acteoside at various concentrations: 0 (control), 10, 30 and 50 μM. The oocytes maturation rates of groups supplemented with acteoside were no significantly different (81.13, 85.96, 82.95 and 83.68%, respectively). Level of ROS was significantly decreased in acteoside treated group. Furthermore, the parthenogenetic blastocyst rate was significantly improved in 10 μM acteoside treated group compared with control group (44.83 vs. 27.75%). And we investigated effect of acteoside on the oocytes condition represented by cytoplasmic maturation by homogeneous distribution and formation of cytoplasmic organelles and regulation of apoptosis-related genes. In the results. during IVM, 10 μM acteoside treated oocytes showed that the mitochondria and lipid droplet were smaller and homogeneous distribution in cytoplasm compare with control oocytes. And reverse transcription polymerase chain reaction (RTPCR) of parthenogenetic blstocysts revealed that acteoside increased the anti-apoptotic genes (Mcl-1, Bcl-2 and Bcl-xL), whereas reduced the expression of pro-apoptotic genes (Bax and Bak). In conclusion, based on the results, the effect of acteoside on IVM was not attractive. However, in acteoside treated group, cytoplasmic maturation seemed to be improved with morphologically uniform distribution of cytoplasmic organelles. Furthermore, embryonic development in acteoside treated group was significantly highly increased than that of non-treated group. Our results represents that addition of acteoside to the IVM medium has a beneficial effect in physiology of porcine oocytes, providing a improved method for porcine oocytes in vitro. * This work was supported by a grant (Code# PJ008148) from BioGreen21 Program, Rural Development Administration, Republic of Korea.
        10.
        2012.06 구독 인증기관·개인회원 무료
        The objective of the current study was to describe in vitro embryo production in Hanwoo, analyzing oocytes yield and embryo production. The effects of oocytes production and the number of OPU procedures per animal on embryo production were also evaluated. OPU was done every 3~4 days during experimental period and collected oocytes were fertilized in vitro in both OPU and needle puncture groups. First, we compared the recovery rate of oocytes based on OPU session (Experiment 1). The average of collected oocytes was calculated from every 10 session. The average number of total oocytes recovered per animalonsessionwas 5.16 (mean). Second, we compared the recovery rate base on collection period of OPU (Experiment 2). The following results show the difference of the number of recovered oocytes in every month during the procedure between the months of session. Every animal shows the constant number of recovered oocytes for the first 5 months. However, the recovery rate of oocytes was decreased from month 6 to 8. Third, we compared the developmental rate to blastocyst in two groups (Experiment 3). Oocytes by needle puncture were fertilized with frozen-thawing semen; the cleavage rate 24~48 h after in vitro fertilization (IVF) was 75.8% and blastocyst development rate was 18.8% in needle puncture group. Even though there is lower cleavage rate after IVF in OPU group (61.1%), blastocyst development rate was higher compared with needle puncture group (28.4%). In conclusion, Blastocyst developmental rate could be increased by OPU than classical method of needle puncture. Improvement of bio- technique in collecting oocytes could be applied to understand the reproductive physiology in cattle, expecially Hanwoo. Therefore, further investigation should be done to clarify the efficiency and advantage of OPU involved in reproduction in animals and human being.
        11.
        2011.10 구독 인증기관·개인회원 무료
        The objective of this study was to evaluate in vitro production of bovine embryos in Hanwoo. Oocytes were collected by ovum pick up (OPU) from ovaries of genetically high-value Hanwoo or by needle puncture from ovaries of slaughtered cattle. OPU was done every 3 4 days duing experimental period and collected oocytes were fertilized in vitro in both OPU and needle puncture groups. First, We compared the in vitro maturation rate in two groups (Experiment 1). 545 oocytes were recoverd from 4 females by 32 trials of OPU and then 433 oocytes were shown MⅡ stage after in vitro maturation (79.4%). In case of needle puncture group, 1905 oocytes were collected and then 1420 oocytes were matured to MⅡ stage during in vitro culture(74.5%). Second, we compared the developmental rate to blastocyst in two groups (Experiment 2). 1420 oocyte by needle puncture were fertilized with frozen-thawing semen; the cleavage rate 24 48 h after in vitro fertilization (IVF) was 88.6% and blastocyst development rate was 20.5% in needle puncture group. Even though there is lower cleavage rate after IVF in OPU group (84.8%), blastocyst development rate was higher compared with needle puncture group (26.4%). In conclusion, Blastocyst developmental rate could be increased by OPU than classical method of needle puncture. Improvement of bio-technique in collecting oocytes could be applied to understand the reproductive physiology in cattle, expecially Hanwoo. Therefore, further investigation should be done to clarify the efficiency and advantage of OPU involved in reproduction in animals and human being. This research was suppoted by Imsil-gun agricultural technology service center.
        12.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        6,300원
        13.
        2002.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        6,300원