• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.53-58
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• 1998

The $H{\beta}$ and some metal line indices, such as Mg2, Fe52 of single-age and single-metallicity populations are computed based on the method of evolutionary population synthesis, with careful consideration of the variation of the horizontal-branch morphology with metallicity and age. We find (a) that while metal lines are little af-fected, the $H{\beta}$ index is severely enhanced (up to 30%)by the presence of the blue horizontal-branch stars, frustrating the current age-estimations from this index with out careful consideration of these stars, and (b) that there is a systematic trend in the sense that the globular clusters in giant elliptical galaxies appear to be older than those in our Galaxy by several billion years. We also calculate these indices for the stellar populations with a metallicity spread, by adopting metallicity distribution functions predicted by chemical evolution models. The comparison of the models with the observed indices of the central regions of the early-type galaxies yields the results (a) that the ages of the giant elliptical galaxies would be older than the previous estimations by several billion years, and (b) that there is a considerable age spread among elliptical galaxies, in the sense that the giant elliptical galaxies are older than small ones.

• Journal of Educational Research in Mathematics
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• v.9 no.2
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• pp.419-438
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• 1999

This paper explored the impact of dynamic geometry software such as CabriII, GSP on student's understanding deductive justification, on the assumption that proof in school mathematics should be used in the broader, psychological sense of justification rather than in the narrow sense of deductive, formal proof. The following results have been drawn: Dynamic geometry provided positive impact on interacting between empirical justification and deductive justification, especially on understanding the necessity of deductive justification. And teacher in the computer environment played crucial role in reducing on difficulties in connecting empirical justification to deductive justification. At the beginning of the research, however, it was not the case. However, once students got intocul-de-sac in empirical justification and understood the need of deductive justification, they tried to justify deductively. Compared with current paper-and-pencil environment that many students fail to learn the basic knowledge on proof, dynamic geometry software will give more positive ffect for learning. Dynamic geometry software may promote interaction between empirical justification and edeductive justification and give a feedback to students about results of their own actions. At present, there is some very helpful computer software. However the presence of good dynamic geometry software can not be the solution in itself. Since learning on proof is a function of various factors such as curriculum organization, evaluation method, the role of teacher and student. Most of all, the meaning of proof need to be reconceptualized in the future research.

• Knowledge Management Research
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• v.15 no.4
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• pp.171-187
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• 2014

The social network services (SNS) like Facebook, have gained an enormous amount of popularity. However, side-effects of Facebook usage are occasionally reported such as sense of alienation and cyber-bullying. Among these potential factors threatening to the success of SNS, this research focused on alienation and intends to investigate possible factors that affect SNS alienation and how it affects on SNS attachment and proactive use of SNS. Through extensive literature reviews regarding online and offline alienation, SNS characteristics, and SNS usage, we generated the research model and hypotheses. We surveyed 142 Facebook users and empirically proved that among SNS characteristics, complexity increases SNS alienation, and interactivity and social presence positively affect SNS attachment. Offline alienation, one of the personal attributes, increases both SNS alienation and SNS attachment at the same time while the number of SNS friends have no significant effects. In addition, SNS alienation decreases proactive use of Facebook while SNS attachment increases it. Theoretical and practical implications are discussed based on research findings, and we also suggest future research directions to minimize negative consequences due to SNS users' sense of alienation.

• Journal of Plant Biotechnology
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• v.7 no.1
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• pp.51-55
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• 2005

Many cloning vectors in which cDNAs can be inserted to the sense orientation have been developed. Uni-ZAP XR vector (Stratagene) should contain clones that are oriented to sense direction with respect to T3 RNA polymerase primer. Unexpectedly, large portions of cDNAs in Chinese cabbage cDNA library showed unusual insertions, antisense orientation and a hybrid of two different clones. Using two clones, 4H03 and 53-B10, derived from different cDNA libraries, we proposed and demonstrated the possibility of unusual-construct formation by in vitro translation and northern blot analysis. The 4H03 clone was inserted with inverse direction, and its transcript and translation product could be produced by T7 RNA polymerase, indicating that this clone is definitely inserted into inverse orientation. The 53-B10 that contains two independent genes was turned out to be a hybrid in which two genes are inserted to opposite direction each other. All unusual constructs might be due to the presence of small fragments of DNA, like adapter. However, the mechanism underlined the formation of unusual constructs is still remain to be solved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.351-352
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• 2021

Due to the recent rapid change in the social environment due to Corona 19, the need for non-face-to-face/contact-based information exchange technology is rapidly emerging. Due to these changes, the development of an alternative system using a sense of immersion and a sense of presence is urgently required. In this study, in order to implement a video conferencing system, we implemented a technology for transmitting large-capacity 3D data in real time without delay. For this, the applied algorithm of GAN, the latest deep learning algorithm of the unsupervised learning series, was used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.919-927
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• 2008

The growing availability of broadband multimedia applications are providing strict real-time services and enabling users to feel much interactivity as well as 'sense of presence'. In that sense, there would be increased demand for what network and system have to do to fulfill the user expectations. In this paper, we implement a real-time multimedia application which make use of real-time DXT CODEC and investigate what the challenges of networking and system are. We carry out various experiments over a research network test-bed to evaluate the performance of our proposals.

• Fashion & Textile Research Journal
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• v.21 no.4
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• pp.401-411
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• 2019

Non-contact judgment and evaluation for products are increasingly needed along with a rapid environmental change in fashion that sows urgency in the need to implement services that allows users to judge and experience a tactile sense in a fashion product without actual contact. Technological development is required to provide users with syn-aesthetic experiences that integrate the visual, tactile and the auditory. There is also a need to conduct research to increase immersion that provides users with ICT-related experiences communicated through fashion images. The study analyzed demands for haptic communication technology by Korean users in immersive VR fashion product shopping. Accordingly, it defined haptic communication through literature research, investigated immersion in the VR environment and conducted in-depth interviews for haptic communication applicable to VR shopping. Findings show that hedonic reactions by fantasy, emotion and fun function are an important motive in selecting VR shopping. VR fashion product shopping steps were divided into 4: move to store, search in store, search of product and purchase based on offline store shopping experience. It defined the haptic communication by steps and analyzed the types of the haptic feedback to be implemented. The study results provide basic data for developing haptic communication technology that can enhance e a sense of the presence and immersion experiences that can help lay a groundwork for pilot studies on the convergence of the virtual and the real.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.64-70
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• 2008

Computer Assisted Learning (CAL) is quite different from in many aspects. CAL provides individualistic learning environment and facilitates autonomy of the learner. Thus the learners who uses CAL program has more sense of control and engages in more strategic learning than conventional learning environment. In this experiment, we used KORI (KORea university intelligent agent) which is a new type of ITS adopting TA (Teachable Agent) that fosters learning by teaching, So, we investigated the critical motivational factor that have influences in CAL learning and the effects of reward in CAL are another area of our interest. Thus, we divided two conditions that presence of reward and absence of reward. The 174 elementary school students(5th) were participated and they are randomly assigned the one of the reward conditions. Before entering the experimental instruction, all participants measured about metacognition, self-efficacy and goal orientation questionnaire as independent variables. Then, Participants were instructed of method of using KORI program and asked to study for ten days with KORI program at least 20 minutes everyday in their home, about 10 days. After 10 days, they were rated interest and comprehension. Regression results suggest that regardless of the presence of reward, metacognition is a positive predictor in interestingness. It indicate that metacognitive skills are required in CAL learning situation irrespective of reward. But on comprehension in the absence of reward, only self- efficacy appeared to be a positive predictor. In the presence of reward, performance goal orientation showed as a negative predictor of comprehension, whereas self-efficacy was a positive predictor. This result suggest that presence of reward especially interferes learning process of performance goal orientation in CAL learning situation. It could be interpreted that reward interferes the learning process of performance goal orientation by debilitating intrinsic motivation.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.198-210
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• 2013

This study investigates the detrimental effect of watching sexual content in three-dimensional (3D) moving pictures. An increasing amount of investment is put especially in 3D adult content to boost their 3D media industries. It is crucial that the effect of sexual contents on viewers be identified. In this experiment, a between-subject design was employed to analyze various effect of sexual content on participants whether they viewed the same stimuli in 3D or in 2D. In particular, the presence scaling was used to evaluate how real the video clip is. In addition, the permissiveness toward sexual behaviors and the level of sexual arousal were measured to examine the different effect of sexual content by dividing two separate groups in 2D and 3D condition. The result shows that those who watched a 3D video clip perceived higher sense of presence compared to those who watched a 2D video clip. Furthermore, subjects in 3D condition reported lower scores of permissive attitude toward sexual behaviors. This confirms that 3D display delivers more visual experience and has an impact on people in terms of perceiving sexual contents and changing their attitudes towards sexual behaviors.

• Journal of Communications and Networks
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• v.17 no.4
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• pp.440-448
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• 2015

In this paper, we study the problem of selfish behavior of secondary users (SUs) based on cognitive radio (CR) with the presence of primary users (PUs). SUs are assumed to contend on a channel using the carrier sense multiple access with collision avoidance (CSMA/CA) and PUs do not consider transmission of SUs, where CSMA/CA protocols rely on the random deference of packets. SUs are vulnerable to selfish attacks by which selfish users could pick short random deference to obtain a larger share of the available bandwidth at the expense of other SUs. In this paper, game theory is used to study the systematic cheating of SUs in the presence of PUs in multichannel CR networks. We study two cases: A single cheater and multiple cheaters acting without any restraint. We identify the Pareto-optimal point of operation of a network with multiple cheaters and also derive the Nash equilibrium of the network. We use cooperative game theory to drive the Pareto optimality of selfish SUs without interfering with the activity of PUs. We show the influence of the activity of PUs in the equilibrium of the whole network.