• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5C
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• pp.493-505
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• 2003

A new inter-client synchronization framework for multicast media streaming is proposed employing a server-client coordinated adaptive playout control. The proposed adaptive player controls the playback speed of audio and video by adopting the time-scale modification of audio. Based on the overall synchronization status as well as the buffer occupancy level, the playout speed of each client is manipulated within a perceptually tolerable range. Additionally, the server implicitly helps increasing the time available for retransmission while the clients perform an interactive error recovery mechanism with the assistance of playout control. The network-simulator based simulations show that the proposed framework can reduce the playout discontinuity without degrading the media quality, and thus mitigate the client heterogeneity.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.56-64
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• 2020

This paper is a follow up to the previous study which reveals that smartphone users are divided into three subcategories according to their usage characteristics. In this paper, these groups are called as 'general', 'entertainment', and 'work-assistant', taking into account their respective characteristics. The 'general' is a group whose smartphone usage characteristics are not focused on a specific purpose, the 'entertainment' is focused on music, internet, SNS, picture, and e-banking, and the 'work-assistant' is on work, GPS, diary. Inter-relation between the importance and satisfaction for the purchase determinants to the groups is investigated. In addition, Kano analysis of quality attributes is also performed, which includes quality type, satisfaction/dissatisfaction index, and PCSI (Potential Customer Satisfaction Improvement) index. The analysis result are as follows. Firstly, inter-relation between importance and satisfaction differs by user group. 'Internet', 'Ease of use', and 'Performance' purchase determinants are evaluated as competitive determinants in 'work-assistant' user group. Secondly Kano quality types of quality characteristics also differs by user group. 'Application' was classified as an attractive (A) types to 'entertainment' group and so on. 'Internet' 'Failure/Bug', 'Touch response rate' and 'Charging' are located in 'Nice' Region of S-PCSI Diagram and have to be considered as strategic quality characteristics. The results of this study is expected to give some helps in establishing a customer tailored quality strategy.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.499-510
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• 2011

Any server offering a routing service in the Internet would naturally be in competition for clients, and clients may need to utilize service from a specific server in order to achieve a desired result. We study the various properties of this competition, such as the fraction of route requests handled by a routing service provider and the fraction of total revenue obtained. As the routing service providers (i.e., servers or routers in this context) compete, they may alter behavior in order to optimize one of the above properties. For example, a service provider may lower the price charged for its service, in order to increase the number of clients served. Our models are based on servers offering a routing service to clients within representative network topologies based on actual Internet sub-graphs. These models provide, a framework for evaluating competition in the Internet. We monitor key aspects of the service, as several variables are introduced into the models. The first variable is the fraction of client requests that will pay more for a better quality route. The remaining requests are normal client requests that are satisfied by the most economical route. The second variable is the fraction of servers who choose to lower service prices in order to maximize the number of client requests served. As this fraction increases, it is more likely that a server will lower the price. Finally, there are some resource constraints applied to the model, to increase the difficulty in providing a routing solution, i.e., to simulate a realistic scenario. We seek to understand the effect on the overall network, as service providers compete. In simple cases, we show that this competition could have a negative impact on the overall efficiency of a service. We show that the routing variety present in the larger models is unable to mask this tendency and the routing service performance is decreased due to competition.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.235-241
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• 2004

There is a growing concern about the possible increase in inter-annual variation of minimum temperature during the winter season in Korea. This view is strengthened by frequently reported freezing injury to dormant fruit trees, while warmer winters have prevailed recently. The January minimum temperature record at fourteen weather stations was analyzed for 1951-2000. The results showed no evidence of increasing standard deviation at 3 locations between 1951-1980 and 1971-2000, while the remaining 11 stations showed a trend of decreasing standard deviation for the two periods. An empirical model explaining the spatial variation of the standard deviation was derived by regression analysis of 56 stations' data for 1971-2000. Daily minimum temperature and the site elevation may account for 68% of the observed variations. We applied this model to restore the average standard deviation of the January minimum temperature for 1971-2000, and the result was used to produce gridded minimum temperature data for the recurrence interval of 10 and 30 years at 250m resolution. A digital form of the plant hardiness zone map may be developed from this product for site-specific selection of adapted plant species.

• Journal of Korean Medical Science
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• v.33 no.51
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• pp.340.1-340.14
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• 2018

Background: Various pneumococcal vaccines have been evaluated for immunogenicity by opsonophagocytic assay (OPA). A multiplexed OPA (MOPA) for 13 pneumococcal serotypes was developed by Nahm and Burton, and expanded to 26 serotypes in 2012. The development of new conjugate vaccines with increased valence has necessitated expanded MOPAs to include these additional serotypes. In this study, we validated this expanded MOPA platform and applied to measure antibodies against 11 additional serotypes (2, 8, 9N, 10A, 11A, 12F, 15B, 17F, 20B, 22F, and 33F) in human sera. Methods: All materials, including serum, complement, bacterial master stocks, and HL-60 cells, were evaluated for assay optimization. Following optimization, the assay was validated for accuracy, specificity, and intra- and inter-assay precision with sera from adult donors following standard protocols. The assay was applied to evaluate functional antibodies of 42 sera immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23). Results: The expanded MOPA platform was specific for all serotypes, with the exception of serotype 20. The assay results were highly correlated with those obtained from single-serotype OPA, indicating acceptable accuracy. The coefficients of variation were 7%-24% and 13%-39% in tests of intra- and inter-assay precision, respectively, using three quality-control samples. A MOPA that included 11 additional serotypes in the PPV23 was established and validated with respect to accuracy, specificity, and precision. The opsonic indices of immune sera were obtained using this validated assay. Conclusion: The expanded MOPA will be useful for evaluation of the immunogenicity of PPV23 and future conjugate vaccine formulations.

• Plant Breeding and Biotechnology
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• v.5 no.4
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• pp.371-389
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• 2017

Supplying sufficient rice to growing populations is a global challenge. Hybrid indica rice varieties exploiting heterosis have increased yields, but inter-subspecific crosses between indica and japonica varieties are hampered by sterility. Examination and genetic understanding of yield heterosis in indica/japonica crosses addressing yield barriers are basic requirements. In this study, QTLs for heterosis of yield traits were identified in indica-japonica recombinant inbred lines (RILs) using a total of 178 RILs originating from Dasanbyeo (indica) ${\times}$ TR22183 (japonica) (DT-RILs) and their backcrossed populations. Nine of sixty-six major quantitative trait loci (QTLs) identified in DT-RILs exhibited heterosis. Heterosis QTLs clustered with other traits on chromosomes 1, 4, and 8, and clusters were conserved between different RILs. The clusters contained several known yield enhancement genes/QTLs. Specific heterotic allele combinations contributed to four major heterosis QTLs, particularly for panicle and spikelet number traits. Heterosis for yield and yield-related traits was explained by the harmonized effects of overdominance, dominance, and epistatic interactions in inter-subspecific breeding populations.

• Analytical Science and Technology
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• v.32 no.3
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• pp.96-104
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• 2019

Agastache rugosa, known as Korean mint, is a medicinal plant with many beneficial health effects. In this study, a simple and reliable HPLC-UV method was proposed for the quantification of rosmarinic acid (RA) in the aqueous extracts of A. rugosa. RA was selected as a quantification marker due to its easiness in procurement and analysis. The developed method involved chromatographic separation on a $C_{18}$ column ($250{\times}4.6mm$, $5{\mu}m$) at room temperature. The mobile phase consisted of water and acetonitrile both containing 2 % acetic acid and was run at a flow rate of $1mL\;min^{-1}$. The method was validated for specificity, linearity, precision, and accuracy. It was specific to RA and linear in the range of $50-300{\mu}g\;mL^{-1}$ ($r^2=0.9994$). Intra-day, inter-day, and inter-analyst precisions were ${\leq}0.91%\;RSD$, ${\leq}1.40%\;RSD$, and 1.94 % RSD, respectively. Accuracy was 93.3-95.9 % (${\leq}1.21%\;RSD$). The method could be applied to three batches of bulk samples and three batches of lab scale samples, which were found to be $0.64({\pm}0.04)mg\;g^{-1}$ and $0.48({\pm}0.02)mg\;g^{-1}$ for the dried raw materials of A. rugosa. The results show that the proposed method can be used as a readily applicable method for QC of health functional foods containing the aqueous extracts of A. rugosa.

• International Commerce and Information Review
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• v.15 no.3
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• pp.353-384
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• 2013

When it comes to the current inter-Korean relationship, the two Koreas are in the step of core practical negotiation on exchanges and cooperation away from deadlock so far. It is expected that they will have more and frequent meetings in the future. Therefore, now is the time the South Korea needed to come up with systematic countermeasures because there is nothing more important and giving more impact on our society than the matter of North Korea. As the purpose of social science lies with the explanation and prediction of the social phenomena in the society, it is considered to be meaningful to analyze the representative military negotiations such as the defense ministry-level talks, general-level talks, and working-level talks between the two Koreas where the participants from South Korea consisting of the military representatives discussed with their counterparts of North Korea since the signing of the armistice in Korea on July 27, 1953. This study analyzes and evaluates the behaviors of North Korea's military negotiations with the South Korea in the Kim Jong-il era on the overall basis. In particular, the research tries to prove that the behaviors of military negotiations under Kim Jeong-il regime were made in the frame of the negotiation model by analyzing many negotiations presented in 'With Century', Kim Il Sung's Memoirs under his anti-Japan-guerilla era and suggesting the analysis frame of anti-Japan-guerilla style negotiation model. Based on the results of this proof, the study looks at carefully the specific characteristics of anti-Japan guerrilla-type negotiation.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.66-74
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• 2004

In order to clarify intra-and inter-specific variation of Korean Rana species, the partial DNA sequences of mitochondrial 16S rDNA gene were determined from 6 Korean and 1 Japanese Rana species, DNA sequences from Korean and Japanese species were comparison-analysed within, and also with the sequences from three species of Japanese brown frogs. DNA similarities were calculated as 91.3∼97.3％ among brown frog (R. amurensis coreana, R. dybowskii and R. huanrenensis), as 96.11∼97.26％ among pond frogs (R. nigromaculata and R. planeyi chosenica). Genetic distance of pond frog and wrinkle fyog (R. rugosa) were near than that of pond frog and brown frog. Two clusters were formed brown frogs and the other group by neigh-bor-joining and maximum-likelihood analysis, also the populations of R. nigromaculata were well distinguished between Korean peninsula and Korean island. But result from maximum-likelihood analysis slightly differed from neighbor-joining to cluster of R. rugosa. Further analyses for their population will be necessary to study the phylogenetic status.

• Journal of Information Technology and Architecture
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• v.9 no.3
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• pp.233-241
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• 2012

Architecture framework (AF) is a guideline to define components needed to develop and operate enterprise architecture (EA), and to define relationships among the components. There are many architecture frameworks to operate EA of governments and businesses such as Zachman framework, DoDAF, TOGAF, FEAF, and TEAF. DoDAF is the most representative AF to support the development of the EA in the military domain. DoDAF is composed of eight viewpoints and 40 views that are affiliated with the viewpoints. To develop an AF for a specific goal, system architects decide a set of views. Furthermore, they determine data that are needed for a view modeling. However, views and data in DoDAF are structurally inter-related explicitly and/or implicitly. So, developing an AF for a specific goal is going to be a project to be carried out over a long haul. To reduce the burden of its development, in this paper, we develop ONT-SAF (Ontology for DoDAF) that can infer inter-relationships like referential and transitive relationships and the sequences among the views. Furthermore, to promote reusability and consistency of the views and the data within an AF, we adopt the view-data separation strategy. ONT-DAT contains classes like 'viewpoint', 'view', 'data', 'expression method', and 'reference model', and 11 properties including 'hasView.' To prove the effectiveness of ONT-SAF, we perform a case study.