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        검색결과 213

        63.
        2017.07 구독 인증기관 무료, 개인회원 유료
        Introduction Literally explosive is the growth of social media. The estimated number of monthly active Facebook users by the fourth quarter of 2016 is around 1.86 billion, almost a quarter of the world population, meaning that one in four people on the globe uses Facebook to read news, share gossips, communicate ideas, and build relationships with others. In the United States alone, 72% of all Internet users are reported to use Facebook (Pew Research, 2015), and to many, Facebook is no longer a small part of the Internet, but rapidly becoming the Internet itself. As peer-to-peer information sharing becomes a global mainstream, concerns about the credibility of information shared online is growing fast as well. With no gatekeeper in a traditional sense, rumors and fabricated information lacking reliable evidences (e.g., fake news) may spread wide and fast, and individuals are left alone to assess and judge which among them is likely to be true (Metzger, Flanagin, & Medders, 2010). Unfortunately, we know very little about how individuals assess information fed through online social networks, and how such processing of information in the social media environment differs from those in traditional media environment. In social media like Facebook where individuals and organizations interact through direct or indirect social relationships, what people can give and take is partly determined by with whom they have relationships and their locations in the entire network (Brands, 2014). For example, if one’s network consists mostly of college students, the network may be flooded with gossips, news, and information particularly appealing to them (e.g., how to pull an A from the hideous professor). If the network is made up of people from diverse backgrounds, meanwhile, the information shared therein will be as diverse as heterogeneous are the members’ characteristics and preferences. Network topology may, therefore, be a crucial factor that shapes not only what you encounter in your own network, but also the way you assess the information found therein (Sohn, 2014). An identical message may be construed differently depending on how it has been encountered (e.g., who liked/shared in Facebook) as well as where it originates (e.g., who are the original source of the message). For instance, the news regarding the effectiveness of alternative medicine on curing cancer may be assessed differently depending on whether it is shared by lay people with similar interest or medical experts, which subsequently affects one’s decision to share it. Whereas it is already well-founded that the original source quality plays an important role in communication (Visser & Cooper, 2007), relatively little attention has been devoted to unveiling the role of intermediate social environment lying between the original source and the final recipients. This study is aimed at examining systematically the role of social relations in individuals’ assessment of and decision to share information encountered in social media. More specifically, the focus will be on testing in an experimental setting how social relationship properties, reflecting psychological distance, shape individuals’ assessment of risk/benefit associated with the information received. Psychological Distance and Decision under Risk We are routinely exposed to a myriad of information from our immediate social circles including close friends and acquaintances as well as mass media. Some of them could be about the opportunities for earning extra profits (e.g., stock or real estate investment opportunities), while others about how to maintain better health (e.g., avoiding harmful chemical-intake). Whether it is about money, health or others, the decision to take an action on the information is a function of how to assess the risks involved. According to the prospect theory (Kahneman & Tversky, 1979), people have an inherent tendency of being more sensitive to the loss than benefit of anything, making them prefer avoiding loss to having an equivalent amount of gain. This loss-aversive tendency also implies that people prefer the possible to sure loss, even if the former is greater than the latter. In other words, people become risk-seeking to avoid any loss with certainty. Suppose, for example, you are given a choice between losing $750 for sure and doing a gamble such that you lose $1000 with 75% chance or lose nothing with 25% chance. Despite the identical expected value ($1000 x .75 + $1000 x 0 = $750), people tend to lean over to the gamble rather than the sure loss. This may work in the opposite way for benefit – you may prefer the sure to possible gain, meaning that you become risk-aversive when benefit is at stake. An interesting question is whether such a risk-seeking or aversion tendency is malleable (Tversky & Simonson, 1993). It is widely known that a message with identical contents can be construed differently depending on whether it is stated or framed in terms of benefit or loss (Slovic, 1995). Then, we might ask whether people construe messages differently depending on where they are from – whether they are from close-knit groups, distant acquaintances or some anonymous others. Prior studies have seldom considered such social contextual influence, which is essential to understanding communication in social media (Sohn, 2014). Suppose you are considering taking an alternative medicine for treating a chronic illness of yours, which will surely get worse with no treatment (i.e., loss with certainty). The alternative medicine’s effectiveness is largely unknown and has never been under rigorous scientific tests. You post your thought about adopting it and have just got replies from two different sources in your Facebook network – a close friend and a mere acquaintance. Your friend says that using the alternative approach can be detrimental to your health (i.e., loss frame), while the acquaintance mentions that s/he trusts the medicine’s benefits (i.e., benefit frame). What would be your choice given the comments? Would your choice be reversed if your friend says its benefit, while the acquaintance warns its side effects? It is posited in construal-level theory that “people use increasingly higher levels of construal to represent an object as the psychological distance from the object increases” (Trope & Liberman, 2010, p. 441). When there are pros and cons with respect to a course of action, people perceive cons (i.e., losses) psychologically closer than pros (i.e., benefits), which provides an explanation of why loss aversion occurs. In addition, it has been found that pros become more salient than cons as temporal distance to the action increases (e.g., buying a computer a year later; Eyal, Liberman, Trope, & Walther, 2004). Taken together, it may be inferred that the cons are salient when the action of interest is thought psychologically proximal, but the pros become more salient as it gets more psychologically distant. This inference can be applied to other distance dimensions including social distance as well. Combining benefit-loss frames and social distance perceptions, we can come up with the following four different conditions as summarized in Table 1. With all other things held equal, people tend to feel loss psychologically closer than benefit. However, the salience of either benefit or loss in a person’s mind may also depend on how the information is presented -- whether a message with the information comes from a proximal or distant source. For example, if a message with emphases on an alternative medicine’s benefit came from a proximal source (BP), further decrease in psychological distance might make salient its potential side effects, and thus lessen the benefit’s influence on decision. Similar inferences can be made to the case when a message with emphases on loss came from a distant source (LD). Due to the increase in psychological distance, it might become difficult to think of the negative aspects of the target (Herzog, Hansen & Wanke, 2007). If the message emphasizing either benefit or loss is aligned respectively with a distal (BD) or proximal source (LP), in contrast, they will become more salient in the person’s mind, which would exert a disproportionate influence on decision. Given the discussion, the following hypotheses can be proposed: H1a. People perceive the benefit more salient, and thus are more likely to make a risky choice when it is supported by socially distant others than when no information of the social distance to the source is given (i.e., control condition). H1b. People perceive the benefit less salient, and thus are less likely to make a risky choice when the benefit is supported by socially close others than when no information of the social distance to the source is given (i.e., control condition). H2a. People perceive the loss more salient, and thus make a risky choice less when the loss is warned by socially close others than when when no information of the social distance to the source is given. H2b. People perceive the loss less salient when the loss is warned by socially distant others than when no information of the social distance to the source is given. Experimental Design A 2 (message frames) x 3 (social distance) between-subjects online experiment will be conducted as follows. Subjects will be given multiple hypothetical risky choice situations with respect to such issues as making an investment, adopting a new medical treatment, purchasing a product. After being exposed to the choice scenarios, they will be asked a series of questions for measuring their issue-involvement levels, attitudes to the issue presented, thoughts related to benefits and losses, and final choices, along with relevant psychological and demographic characteristics. Implications No communication ever occurs in a social vacuum. Just as our everyday behaviors are shaped and often constrained by the physical places in which they are performed (e.g., rooms, streets, buildings), we communicate in a social setting consisting of direct and/or indirect relationships among people (Gifford, 2013). The knowledge of one’s social surroundings becomes more important in social media due to the manifest location dependency—meaning one’s position in a relationship network basically defines what can be seen and done. No matter whether information originally came from a newspaper, television program, or blog, the information is eventually transmitted via one of the network members, highlighting the importance of relationship patterns and qualities in communication processes. That is, in any socially-networked environment, people rely not only on inferences about the original source quality (e.g., authority, expertise), but also on the social contexts through which the information is received and shared. Most previous research has focused mainly on the former (i.e., source quality) while overlooking both the latter (i.e., social contexts) and any possible interactions between the two (Metzger, Flanagin, & Medders, 2010). The current study is believed to bridge the gap so that communication processes in the social media environment could be understood in a more systematic fashion.
        4,000원
        64.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Prion diseases are a class of transmissible fatal disorders. In order to identify alterations associated with the pathogenesis of prion diseases, several studies have been conducted involving differential gene expression analysis using cDNA libraries, mRNA differential displays, and gene microarrays. These genomic approaches may be useful for identifying genes that are differentially expressed in prion diseases and that may participate directly or indirectly in the pathogenesis of the disease. In this study, we compared the gene expression profiles of normal and CWD-infected TgElk mice using the GeneFishing differentially expressed gene (DEG) screening system and real-time PCR analysis. DEGs were screened using the ACP-based PCR method with GeneFishing synthesis. In order to validate candidate genes, we used quantitative PCR (qPCR), and eleven DEGs were identified. Five of these eleven DEGs were upregulated and two were downregulated in the CWD mice. The DEGs newly identified in this study may be useful for diagnosing and studying the pathogenesis of prion diseases.
        4,000원
        67.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The genetic algorithm (GA), one of the artificial intelligence (AI), is developed based on Darwin's theory of evolution, i.e., the mating of randomly selected objects. If more optimal solution is generated, then it is better to repeat the process of setting the optimum value. In this paper, the method of background music using the genetic algorithm is exploited when the computer game is executed each time. As a result, it has created several music that can be used in the actual game, and it could be confirmed that the other music that is created is different music when performed each time.
        4,000원
        69.
        2015.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report first results from KVN and VERA Array (KaVA) VLBI observations obtained in the frame of our Plasma-physics of Active Galactic Nuclei (PAGaN) project. We observed eight selected AGN at 22 and 43 GHz in single polarization (LCP) between March 2014 and April 2015. Each source was observed for 6 to 8 hours per observing run to maximize the uv coverage. We obtained a total of 15 deep high-resolution images permitting the identification of individual circular Gaussian jet components and three spectral index maps of BL Lac, 3C 111 and 3C 345 from simultaneous dual-frequency observations. The spectral index maps show trends in agreement with general expectations – flat core and steep jets – while the actual value of the spectral index for jets shows indications for a dependence on AGN type. We analyzed the kinematics of jet components of BL Lac and 3C 111, detecting superluminal proper motions with maximum apparent speeds of about 5c. This constrains the lower limits of the intrinsic component velocities to  0.98c and the upper limits of the angle between jet and line of sight to 20◦. In agreement with global jet expansion, jet components show systematically larger diameters d at larger core distances r, following the global relation d  0.2r, albeit within substantial scatter.
        4,500원
        70.
        2015.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present our efforts for extending the simultaneous multi-frequency receiver system of the Korean Very Long Baseline Interferometry (VLBI) Network (KVN) to global baselines in order to measure the frequency-dependent position shifts in Active Galactic Nuclei (AGN) jets, the so called core shift effect, with an unprecedented accuracy (a few micro-arcseconds). Millimeter VLBI observations with simultaneous multi-frequency receiver systems, like those of the KVN, enable us to explore the innermost regions of AGN and high precision astrometry. Such a system is capable of locating the frequency dependent opacity changes accurately. We have conducted the feasibility test-observations with the interested partners by implementing the KVN-compatible systems. Here we describe the science case for measuring the core shift effect in the AGN jet and report progress and future plans on extending the simultaneous multi-frequency system to global baselines.
        4,000원
        72.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this proceedings, preliminary results of the KVN Source-Frequency Phase-Referencing (SFPR) observation of 3C 66A and 3C 66B are presented. The motivation of this work is to measure the core-shift of these 2 sources and study the temporal evolution of the jet opacity. Two more sources were observed as secondary reference calibrators and each source was observed at 22, 43, and 86 GHz simultaneously. Our preliminary results show that after using the observations at the lower frequency to calibrate those at the higher frequency of the same source, the residual visibility phases for each source at the higher frequencies became more aligned, and the coherence time became much longer; also, the residual phases for different sources, within 10 degrees angular separations, follow similar trends. After reference to the nearby calibrator, the SFPRed maps were obtained as well as the astrometric measurements, i.e. the combined coreshift. The measurements were found to be affected by structural blending effects because of the large beamsize of KVN, but this can be corrected with higher resolution maps (e.g. KAVA maps).
        3,000원
        73.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        By probing nuclear regions and the overall properties of AGN hosts as a function of their environments, we aim to observationally examine how AGN activities are related to their surroundings. We have selected a representative sample of AGN hosts in the Virgo cluster. The selected galaxies are located in a range of density regions showing various morphologies in 1.4 GHz continuum emission. High-resolution obser- vations with the Korean VLBI Network (KVN) allow us to access the inner region of the AGN without suffering from dust extinction and synchrotron self-absorption. Since a number of our targets are too weak to be detected at K-band (22 GHz) within their coherence time, we applied phase referencing to calibrate fast atmospheric phase uctuations.
        3,000원
        74.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the study was to investigate the neural substrates associated with processing anger among young males with alcohol use disorders (AUDs) using functional magnetic resonance imaging (fMRI). Eighteen individuals with AUD and 15 demographically similar non-abusers participated in the study. Participants were scanned on their brain functioning while they viewed an audio-visual film clip that was previously designed specifically to induce anger emotion, followed by anpsychological assessment. Greater brain activities were detected in the left inferior frontal gyrus (IFG) and dorsal anterior cingulate cortex (dACC) among subjects with AUD compared to the controls during the exposure to anger-provoking stimuli. Despite the same level of subjective anger during anger induction, the greater activations both in the IFG and dACC regions may suggestthat individuals with AUD have a greater propensity to undergo cognitive control and self-regulation while experiencing anger.
        4,000원
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