• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.977-985
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• 2012

Recently, many countries have been developing new protocols to improve the performance of tactical ad hoc networks for implementing NCW (Network Centric Warfare). Combat net radio (CNR) networks are the most important communication infra for the ground forces such as infantry of Army. U.S. Army had developed MIL-STD-188-220D that is the Interoperability Standard for DMTDs (Digital Messages Transfer Device Subsystems) for voice and data communication in CNR. MIL-STD-188-220D is a candidate for MAC protocol of TMMR which is next radio and has a few constraints to used in TMMR. NAD (Network Access Delay) defined in MIL-STD-188-220D needs time synchronization to avoid collision. However, it is difficult for time synchronization to fit in multi-hop environment. We suggest the enhanced DAP (Deterministic Adaptable Priority)-NAD to prevent conflicts and decrease delays in multi-hop CNR. Simulation results show that the proposed scheme improves the performance in multi-hop CNR networks.

• (The) Korean Journal of Advertising
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• v.28 no.3
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• pp.53-81
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• 2017

As online video advertising market grows, viral advertising is drawing attention. This study investigated factors influencing consumer's sharing intent of viral advertising each from four dimensions which are content, sender, consumer, and network. As a result, factors of persuasive intent, brand-ad image fit, perceived self-presentation, and bridging social capital were found to affect consumer's sharing intent of viral advertising. And persuasive intent of content was found to be negatively affect consumer's sharing intent. Social value and bonding social capital were not found to have significant influence on consumer's sharing intent of viral advertising. From the analysis of this result, this study suggested future research topic and academic/practical implications.

• Journal of Biosystems Engineering
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• v.33 no.5
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• pp.362-369
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• 2008

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.593-606
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• 2019

This study examines effective message strategies that fit with the characteristics of retargeting advertisements, based on the Construal Level Theory. First, we investigate whether the social distance that applies between interpersonal interactions can also be observable in an online environment and test the effects of social distance, depending on the type of online sites. We then examine consumers' construal level when social and temporal distances interplay, and how the effects of the messages change accordingly. As a result, social distance and message construal levels by website type were consistent with existing CLT studies. However, the hypothesis that advertising effects will be higher only when all, multidimensions' distances and construal levels of messages match, was partially supported. Also the current view, that the consumers' evaluations will show no difference to when either or both dimensions are distal, was rejected. Instead, when a discrepancy between temporal and social distance was present, the construal level of the message was more effective when congruent with the social distance out the two dimensions. Hence, it is possible to infer that the influence of psychological distance may vary depending on the dimension of distance.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.97-105
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• 1993

Adenosine receptors in rat adipose tissues have been reported to be of $A_{1}$ subclass, and their stimulation leads to inhibition of adenylyl cyclase, resulting in inhibition of lipolysis. In the present study we investigated changes in $A_{1}$ adenosine receptor-adenylyl cyclase system of adipocytes following induction of experimental diabetes in rats. One week following experimental diabetes were induced by intravenous injection of streptozotocin (50 mg/kg body wt.), adipocytes from rats $(170{\sim}230g)$ fed ad libitum were isolated using collagenase. When adipocytes were incubated for 1 h with 1 unit/ml adenosine deaminase and $1\;{\mu}M$ isoproterenol, and assayed for glycerol formation, it was found that the inhibition of lipolysis in diabetic adipocytes by $(-)-N^{6}-(R-phenylisopropyl)adenosine$ (PIA), an $A_{1}$, adenosine receptor agonist, was twice that of control adipocytes. In an effort to delineate the mechanism(s), $[^{3}H]PIA$ binding to adipocytic membranes from diabetic and control rats were determined. Neither the affinities nor numbers of $A_{1}$ adenosine receptor were significantly different from each other (Best fit parameters for the one-site model are: $K_{d}=0.51{\pm}0.09nM$ and $B_{max}=1.60{\pm}0.12\;pmoles/mg$ protein for control membranes; $K_{d}=0.54{\pm}0.21\;nM$ and $B_{max}=1.72{\pm}0.31\;pmoles/mg$ protein for diabetic membranes). However, the inhibiton by PIA of the isoproterenol-stimulated adenylyl cyclase activities was found to be 1.9 times higher in adipocytic membranes from diabetic rats than those from controls. These results suggest that the increased sensitivity of inhibition of lipolysis to PIA in adipocytic membranes from diabetic rats is due to changes in signal transduction pathways, rather than alterations of $A_{1}4 adenosine receptor molecules themselves.