• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.156-166
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• 2022

Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.866-873
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• 2008

2-Deoxystreptamine is a core aglycon that is vital to backbone formation in various aminoglycosides. This core structure can be modified to develop hybrid types of aminoglycoside antibiotics. We obtained three genes responsible for 2-deoxystreptamine production, neo7, neo6, and neo5, which encode 2-deoxy-scyllo-inosose synthase, L-glutamine: 2-deoxy-scyllo-inosose aminotransferase, and dehydrogenase, respectively, from the neomycin gene cluster. These genes were cloned into pIBR25, a Streptomyces expression vector, resulting in pNDOS. The recombinant pNDOS was transformed into a non-aminoglycoside-producing host, Streptomyces venezuelae YJ003, for heterologous expression. Based on comparisons of the retention time on LC-ESI/MS and ESI-MS data with those of the 2-deoxystreptamine standard, a compound produced by S. venezuelae YJ003/pNDOS was found to be 2-deoxystreptamine.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.272-277
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• 2010

기존의 클러스터 기반 라우팅 프로토콜들은 클러스터 외부와의 통신을 클러스터 헤드가 전담함으로써 통신 경로의 구성을 단순화하고 클러스터 헤드를 통한 데이터 통신을 가능하게 하였다. 하지만 매 라운드마다 클러스터 헤드의 재선출(re-electioin) 및 클러스터의 재구성(re-clustering)에 드는 비용을 감수해야 한다. 본 논문에서는 클러스터 헤드없이 완전히 분산된 방식으로 클러스터를 구성하여 클러스터 헤드의 재선출 및 클러스터 재구성의 비용을 줄이고, 안정적인 클러스터 구조를 바탕으로 노드 간의 P2P 통신을 지원하는 라우팅 프로토콜(Distributed Cluster-based Routing Protocol, DCRP)을 제안한다. 제안 기법은 각각의 노드가 이웃 노드와의 연결 상태를 감지하여 독립적으로 자신의 상태를 변화시킴으로써 클러스터를 구성한다. 특정 클러스터를 지나는 경로는 완전히 해당 클러스터 내의 노드들의 책임 하에서 관리되기 때문에 에너지 소모를 효율적으로 관리하고 네트워크의 크기에 따른 확장성을 보장할 수 있다. 제안 기법은 시뮬레이션을 통해 기존 기법에 비해 네트워크 구조(topology)의 안정성이 향상되고 제어 메시지의 교환과 경로 설정에 소모되는 비용이 크게 줄었음을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1529-1534
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• 2008

The aim of this study was directed at exploring the possible use of muscle fiber characteristics as new selection traits for improving both porcine lean meat production and quality. A total of 174 (114 Yorkshire, 30 Landrace, and 30 Meishan) pigs were used for this study, and lean meat production ability was estimated by backfat thickness and loin eye area. The Longissimus dorsi muscle was taken in order to measure meat quality and muscle fiber characteristics. Due to the high correlations between total muscle fiber number and most of the performance traits, all pigs were classified into three groups (low, intermediate, or high) by total muscle fiber number using cluster analysis. The high group had the highest loin eye area (p<0.001). The meat quality traits were within normal ranges as reddish pink, firm, and nonexudative (RFN) pork, but the groups classified as intermediate and high had relatively large drip loss percentages (p<0.05), produced more than twice the amount of pale, soft, and exudative (PSE) pork as compared to the low group. The group with a high total muscle fiber number was further classified, based on type 2b fiber percentage, into low or high groups by cluster analysis. The results showed that the low type 2b fiber group had good loin eye area (p<0.05), small drip loss (p<0.05), and did not produce PSE pork. For these reasons, a high total muscle fiber number, with a low percentage of type 2b fibers, may be suitable in selecting for improvements in both lean meat production and meat quality.

• Journal of information and communication convergence engineering
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• v.13 no.2
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• pp.86-96
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• 2015

In mobile communication, mobile services [MSs] (e.g., phone calls, short/multimedia messages, and Internet data) incur a cost to both mobile users (MUs) and mobile service providers (MSPs). The proposed model MobPrice consists of dynamic data pricing schemes for mobile communication in order to achieve optimal usage of MSs at minimal prices. MobPrice inspires MUs to subscribe MSs with flexibility of data sharing and intra-peer exchanges, thereby reducing overall cost. The main contributions of MobPrice are three-fold. First, it proposes a novel k-level data-pricing (kDP) scheme for MSs. Second, it extends the kDP scheme with the notion of service-sharing-based pricing schemes to a collaborative peer-to-peer data-pricing (pDP) scheme and a cluster-based data-pricing (cDP) scheme to incorporate the notion of 'cluster' (made up of two or more MUs) in mobile communication. Third, our performance study shows that the proposed schemes are indeed effective in maximizing MS subscriptions and minimizing MS's price/user.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.41-47
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• 2012

MANET has vulnerable structure on security owing to structural characteristics as follows. MANET consisted of moving nodes is that every nodes have to perform function of router. Every node has to provide reliable routing service in cooperation each other. These properties are caused by expose to various attacks. But, it is difficult that position of environment intrusion detection system is established, information is collected, and particularly attack is detected because of moving of nodes in MANET environment. It is not easy that important profile is constructed also. In this paper, conformal predictor - support vector machine(CP-SVM) based intrusion detection technique was proposed in order to do more accurate and efficient intrusion detection. In this study, IDS-agents calculate p value from collected packet and transmit to cluster head, and then other all cluster head have same value and detect abnormal behavior using the value. Cluster form of hierarchical structure was used to reduce consumption of nodes also. Effectiveness of proposed method was confirmed through experiment.

• Ocean and Polar Research
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• v.33 no.2
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• pp.99-111
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• 2011

To estimate the effects of limitation nutrients for phytoplankton growth and its influences on short-term variations of a winter phytoplankton community structure, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas from 6 to 7 February in Gwangyang Bay, Korea. Also, several algal bio-assay studies were conducted to identify any additional nutrient effects on phytoplankton assemblage using surface water for the assay. The dominant species in the bay was diatom Skeletonema costatum, which occupied more than 70% of total species in most stations (St.1-16) of the inner bay. According to a cluster and multidimensional scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western parts of Myodo lsland, which can be characterized as a semien-closed eutrophic area with high phytoplankton abundance. The second group included most stations from the north-eastern part of Myodo lsland, influenced indirectly by surface water currents from offshore of the bay. The standing phytoplankton crops were lower than those of the first group. The other cluster was restricted to samples collected from offshore of the bay. In the bay, silicon (Si) and phosphorus (P) were not a major limiting factor for phytoplankton production. However, since the DIN: DIP and DSi: DIN ratios clearly demonstrated that there were potential stoichiometric N limitations, nitrogen (N) was considered as a limiting factor. Based on the algal bio-assay, in vivo fluorescence values in N (+) added experiments were higher compared to control and P added experiments. Our results suggested that nitrogen may act as one of the most important factors in controlling primary production during winter in Gwangyang Bay.

• Korean journal of food and cookery science
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• v.32 no.6
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• pp.734-744
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• 2016

Purpose: This study investigated the preference and awareness of consumers residing in the capital area with respect to South and North Korean regional cuisine to provide baseline data for developing effective commercialization strategies. Methods: This survey was conducted among adults over the age of 19 years who were residing in Seoul and Gyeonggi province area, and data analysis was performed using SPSS WIN 18.0. Results: Analysis of the survey participants' preference for South and North Korean regional cuisine showed that Hwanghae province had the highest preference by $4.35{\pm}1.72$ points, whereas Gangwon province had the lowest preference by $3.75{\pm}0.66$ points. Factorial analysis on general characteristics of Korean regional cuisine resulted in 2 factors - 'locality' and 'health'. Cluster analysis showed that participants could be sorted into two clusters by their awareness of Korean regional cuisine - 'the lower cognitive group' and 'the higher cognitive group'. Cluster analysis on the tourism commercialization strategy for Korean regional cuisines showed that 'the higher cognitive group' had significantly higher awareness regarding the following 3 items: 'merchandising strategy', 'popularization strategy' and 'marketing strategy' (p<0.001). Cluster analysis of the world commercialization strategy showed that 'the higher cognitive group' had significantly higher awareness regarding all items of the 'R&D support strategy' and 'Food culture promotion strategy' categories than the 'the lower cognitive group' (p<0.01). Conclusion: Popularization strategies such as value perception based on the well-being concept, and standardization of recipes; merchandising strategies based on storytelling; and food and culture promotional strategies such as Korean cooking classes and food tasting events, were rated as effective commercialization strategies to increase the popularity of Korean regional cuisine.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.48-54
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• 2012

The $[Fe_4S_4]^{2+}$ clusters with 2-, 3-, and 4-pyridinemethanethiolate (S2-Pic, S3-Pic, and S4-Pic, respectively) terminal ligands have been synthesized from the ligand substitution reaction of the $(^nBu_4N)_2[Fe_4S_4Cl_4]$ (I) cluster. The new $(^nBu_4N)_2[Fe_4S_4(SR)_4]$ (R = 2-Pic; II, 3-Pic; III, 4-Pic; IV) clusters were characterized by FTIR and UV-Vis spectroscopy. Cluster II was crystallized in the monoclinic space group C2/c with a = 24.530 (5) $\AA$, b = 24.636(4) $\AA$, c = 21.762(4) $\AA$, ${\beta}=103.253(3)^{\circ}$, and Z = 8. The X-ray structure of II showed two unique 2:2 site-differentiated $[Fe_4S_4]^{2+}$ clusters due to the bidentate-mode coordination by 2-pyridinemethanethiolate ligands. Cluster III was crystallized in the same monoclinic space group C2/c with a = 26.0740(18) $\AA$, b = 23.3195(16) $\AA$, c = 22.3720(15) $\AA$, ${\beta}=100.467(2)^{\circ}$, and Z = 8. The 3-pyridinemethanethiolate ligand of III was coordinated to the $[Fe_4S_4]^{2+}$ core as a terminal mode. Cluster IV with 4-pyridinemethanethiolate ligands was found to have a similar structure to the cluster III. Fully reversible $[Fe_4S_4]^{2+}/[Fe_4S_4]^+$ redox waves were observed from all three clusters by cyclic voltammetry measurement. The electrochemical potentials for the $[Fe_4S_4]^{2+}/[Fe_4S_4]^+$ transition decreased in the order of II, III and IV, and the reduction potential changes by the ligands were explained based on the structural differences among the complexes. The complex III was reacted with sulfonium salt of $[PhMeSCH_2-p-C_6H_4CN](BF_4)$ in MeCN to test possible radical-involving reaction as a functional model of the [$Fe_4S_4$]-SAM (S-adenosylmethionine) cofactor. However, the isolated reaction products of 3-pyridinemethanethiolate-p-cyanobenzylsulfide and thioanisole suggested that the reaction followed an ionic mechanism and the products formed from the terminal ligand attack to the sulfonium.

• Korean Journal of Community Nutrition
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• v.28 no.2
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• pp.95-103
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• 2023

Objectives: The budget gap in the health sector of local governments affects the supply of health services, which can cause the health gap. This study classified local governments according to their financial characteristics, such as local financial independence and health budget level. It analyzed the health behaviors and disease prevalence of local residents to examine the effect of local government financial investment on the health of local residents. Methods: To classify types according to the financial characteristics of local governments, financial independence and the health budget data for 17 local governments were collected from the local fiscal yearbook of the Ministry of Public Administration and Security. The prevalence of chronic diseases and healthy behavior was compared using the 16,333 data of adults between the ages of 30 and 65 years among the original data of the National Health and Nutrition Examination Survey (2016-2020). Results: Cluster analysis was used to classify local governments into five clusters according to the health financial capacity type. A comparison of the prevalence of local residents by cluster revealed a similar prevalence of hypertension, diabetes, and hypercholesterolemia. On the other hand, the obesity rate (P < 0.01), high-risk drinking rate (P < 0.01), aerobic physical activity rate (P < 0.001), and healthy eating practice rate (P < 0.001) were significantly different. In addition, an analysis of the odds ratio based on the Seoul area revealed a higher risk of health behavior of non-Seoul residents. Conclusions: It is necessary to review the universal health promotion project budget considering the degree of regional financial vulnerability from the viewpoint of health equity to narrow the health gap among regions.