• The Journal of Society for e-Business Studies
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• v.25 no.3
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• pp.95-108
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• 2020

The development of 5G technology, which is a next-generation communication technology capable of processing large amounts of data in real-time and solving delays, is drawing attention. Not only in the United States but also Korea, 5G is focused on supporting R&D as a national strategic technology. The strategy for the smart factory, one of the core services of the 5G, aims to increase the flexibility of manufacturing production lines. The existing wired communications devices can be replaced into wireless ones with the ultra-low-delay and ultra-high-speed characteristics of 5G. For the efficient development of 5G technology, it is necessary to keep abreast of the status and trend. In this study, based on the collected data of 1517 Korea patents and 1928 US patents, 5G technologies trend was analyzed and key technologies were identified by network analysis and topic modeling. We expect that it will be used for decision making for policy establishment and technology strategy of related industries to provide the trends of technology development related to the introduction of 5G technology to smart factories.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.636-643
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• 2011

Sludge solubilization using sonification has been increasingly used for sludge volume reduction along with enhancing digestion efficiency during anaerobic biogas production. In this study, either electric field or ultrasonification or in combination with were investigated using three types of sludge (return, excess and mixed at G sewage treatment facility) for the most efficient solubilization. As a the closed loop, 200 L of sludge was continuously passing through the solubilization system at an average flow rate of $0.7m^3/h$, which is equivalent to 3.5 times treated per hour for up to 84 times (24 h). Only implying electric field showed no variation for sCOD/tCOD before and after treatment on sludge solubilization regardless of types of sludge. However, employing the ultrasonic or combined system could both increasingly solubilize sludge with regard to the number of passing-through, which more enhanced by the combined. In addition, VSS/TSS was lowered to in the range of 2 and 6% while its particle size, diameter (0.9) and diameter (0.5) were more minimized than that of raw sludge. For return sludge, ultrasonification was more efficiently facilitated for solubilization, whereas electric field-ultrasonification was more preferably applied for excess and mixed sludge. It is concluded that depending on types of sludge, solubilization system must be selectively applied for the most efficient break-up of them.

• KSBB Journal
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• v.15 no.1
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• pp.100-105
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• 2000

Optimal medium composition, culture conditions, characteristics of phase variation and activity of insecticidal toxin by Xenorhabdus nematophilus isolated and identified from Korean entomopathogenic nematode Steinernema carpocapsae were examined. Optimal medium composition of this strain was 50-70 g/L yeast extract, 3 g/L $K_{2}HPO_{4}$, 1g/L $NH_{4}H_{2}PO_{4}$, 2g/L ${MgSO}_4$$\cdot$${7H}_{2}O$, 10g/L NaCl and, these, yeast extract was found as a limiting nutrient for cell growth. When Monod equation was applied, maxmum specific growth rate and Monod constant were estimated as 0.13 $hr^{-1}$ and 20g/L, respectively. The pH of culture medium increased up to 8.5-9.5 regardless of initial pH 6-7 as the cells continued to grow. The specific growth rate in a 7 L fermentor was 0.18 $hr^{-1}$, which was enhancement 1.4 fold compared to a flask culture. In case of phase variation, phase I fraction was maintained above 90% at the stationary phase for both flask and fermentor cultures. According to oral toxicity test of Gallena mellonella by Xenorhabdus nematophilus, the addition of cell pellets into feed inhibited normal growth of insect larvae and killed completely then after 20 days cultivation. When culture supernatant of this strain was injected into hemolymph of insect larva, the toxicity was strongest at 24hr cultivation in the early exponential phase and gradually decreased as the culture time proceeded.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.52-59
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• 2008

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. To achieve this goal, this study designed a horizontal transfer as the second project continued to the first project that designed a upward and downward traverse unit. A horizontal traverse unit shows a symmetric structure and consists of frame, which consists of four unit tools, motor and reducer, which are fixed at a frame, operation unit with pinions, first traverse unit, and second traverse unit. Constraint conditions based on the operation mechanism with these elements were configured and obtained following results after modeling a model for a traverse motor. In the kinematic expression of sliding motion with one degree of freedom, the sliding motion is constrained. Also, the rack 3 installed at a frame is used to configure possible kinematic constraint conditions of the rack 2 according to the rolling motion of the pinion 2 in the first traverse unit. In addition, the moment of inertia that is a type of kinetic energy in a converted horizontal traverse unit in the side of the reducer can be applied to introduce the moment of inertia of a converted horizontal traverse unit in the side of the reducer by using the sum of kinetic energy in the rack and pinion, which is a part of the horizontal traverse unit. Also, the equation of motion of the converted upward and downward traverse unit in the side of the motor using the equation of motion of the motor. Furthermore, the horizontal traverse unit predetermines the mass of the first and second traverse unit and applied load including the radius and reduction ratio of the pitch circle in the pinion 1 and applied load to the rack 2. Then, a proper motor can be determined using several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. In future studies later this study, a simulation that verifies the results of the previous two stages of studies using a finite element method.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.129-134
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• 2002

194 plantlets regenerated from leaf explants of boxthorn 'Cheonyang' were cultivated to investigate their morphological characteristics in the field for 2 years. Based on the morphology of leaves, 66.1% of them had elliptical type leaf, the same as that of mother plants, while 22.2% in oval type, 7.2% in obovate type, 2.6% in long-obvate type and 2.1% in lanceolate type. They were classified to 4 groups; group A was selected with both high fruit size and fruit yield, group B with only high fruit size, group C with larger or thicken leaf, and group D with multiple brenches. In comparision of production efficiency between the selected groups and mother plants, group A (99741, 99781, 99854, 99870 and 99886) were longer (2.1 to 2.7 mm) in length of fruits and higher in fruit production (15 to 30%) as compared to mother plants. Croup D (99797 and 99892) was higher in leaf production (7.2%) as compared to boxthorn 'CL1-48', which is the highest in leaf production among boxthorn veriaties.

• Journal of Internet Computing and Services
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• v.19 no.4
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• pp.53-63
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• 2018

The traditional mass media function of conveying information and forming public opinion has rapidly changed into an environment in which information and opinions are shared through social media with the development of ICT technology, and such social media further strengthens its influence. In other words, it has been confirmed that the influence of the public opinion through the production and sharing of public opinion on political, social and economic changes is increasing, and this change is already in use on the political campaign. In addition, efforts to grasp and reflect the opinions of the public by utilizing social media are being actively carried out not only in the political area but also in the public area. The purpose of this study is to explore the possibility of using social media based public opinion in educational policy. We collected media data, analyzed the main topic and probability of occurrence of each topic, and topic trends. As a result, we were able to catch the main interest of the public(the 'Domestic Computer Education Time' accounted for 43.99%, and 'Prime Project Selection' topics was 36.81% and 'Artificial Intelligence Program' topics was 7.94%). In addition, we could get a suggestion that flexible policies should be established according to the timing of the curriculum and the subject of the policy even if the category of the policy is same.

• Journal of Life Science
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• v.20 no.7
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• pp.1086-1092
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• 2010

To estimate the genetic characteristics and cumulative power of discrimination (CPD) within Korean native commercial chicken, we used a total of 395 genomic DNAs from six breeds population (Korean Native Red chicken: R, Korean Native Yellow chicken: Y, Korean native Commercial Chicken: C, Ogal chicken: S, Hy-Line Brown: H, White Leghorn: W). Genetic diversity indices including mean allele number among loci, unbiased heterozygosity ($h_i$) within locus, effective number of alleles ($N_e$) and polymorphism information content (PIC) as well as the unbiased average heterozygosity (H) among loci in the populations were calculated using the generated allele frequencies by each marker. Frequencies of microsatellites markers were used to estimate heterozygosities and genetic distances. The nearest distance (0.119) was observed between the C and Y strains. The generated unbiased average heterozygosity among loci in each population was integrated to the global formula of CPD and the result demonstrated that the CPD within the six chicken populations was 99.461%.

• The Korean Journal of Archival Studies
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• no.13
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• pp.41-90
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• 2006

It's needed for the archivists to design a flexible and stable ERMS(Electronic Records Management System) which can ingest and store records through a consistent way and let users search and use records easily what they want. The basis of the design for ERMS are the conceptual composition and the logical and physical structure of the records when they are stored and managed in the ERMS. This paper explains the process of defining components and designing structure of electronic records using 3-layered approaches which consist of conceptual, logical and physical layer and shows advantages of this approaches. After benchmarking the information models of OAIS which is a reference model for the long-term preservation of digital information objects, this paper applies the model of AIP to a record as a 'Record AIP' and discusses the composition and structure of it. It's a critical task to identify mandatory or optional metadata groups which consists of the 'Record AIP's in the conceptual layer. This paper emphases that the metadata group related to services for the record information to users is required as a result of benchmarking OAIS information models. Various issues about the structure of 'Record AIP's are discussed according to the kind of preservation strategy such as migration or emulation and whether the encapsulation of records is required or not in the logical layer.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.59-71
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• 2019

Korea's average annual working hours are among the highest in the OECD. Such long-term work has been a factor that reduces the quality of life by discouraging workers' productivity and interrupting the compatibility of work and family, prompting the government to encourage flexible work systems, such as increasing part-time jobs, but a lack of quality part-time jobs. Part-time work enables flexible labor for workers, but at the same time, workers will involuntarily opt for part-time work as they have poor working conditions and negative social views. In this respect, the effect of the working type on an individual's life is expected to be different. In addition, for women, gender gaps exist in the labor market and the impact of part-time work on life satisfaction is expected to differ from men in terms of working and family alike. Using the data from the 2017 "Seoul Survey Urban Policy Indicator Survey", the ordered logistic regression model was used to analyze the cross-effect of working type and sex on satisfaction. The analysis of the study showed that when other factors were controlled, life satisfaction was high in the order of fulltime female, full-time male, part-time female, and part-time male. In addition, further analysis shows that the parttime female workers have the highest probability of choosing low life satisfaction, while the probability of choosing high life satisfaction is the lowest, and full-time male workers have the lowest probability of choosing low life satisfaction, while the highest probability of choosing high life satisfaction is the highest.

• Journal of Climate Change Research
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• v.2 no.3
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• pp.175-189
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• 2011

In this research, we describe the methodology and the quantification about GHG reduction effects, expected by optimization of operation mode according to establishing additional heat storage system of Bundang Combined Cycle Power Plant. As an intermediate form of General Combined Cycle Power Plant and Heat supply only district heating plant, Bundang Combined Cycle Power Plant(and Ilsan, Anyang, Bucheon) is possible to satisfy demand for the electrical load and thermal load capacity at the same time through changes to the operation mode itself. Therefore, through the operating transition of high-efficiency mode that the condenser cooling water is recovered and supplied to district heat and cooling, establishing additional heat storage system have flexible supply ability at the power and heat market. In this research, We calculated using the operating performance for the last three years(2008~2010) and efficiency of each mode-specific values. As a result, GHG reduction effects were calculated as $97.95kg_{-}CO_2/Gcal$ per heat energy 1 Gcal supplied at the heat storage system and we expected emmision reduction effect about $13,500Ton_{-}CO_2/yr$.