• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.213-225
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• 2009

A stationary Markov chain model is a stochastic process with the Markov property. Having the Markov property means that, given the present state, future states are independent of the past states. The Markov chain model has been widely used for water resources design as a main tool. A main assumption of the stationary Markov model is that statistical properties remain the same for all times. Hence, the stationary Markov chain model basically can not consider the changes of mean or variance. In this regard, a primary objective of this study is to develop a model which is able to make use of exogenous variables. The regression based link functions are employed to dynamically update model parameters given the exogenous variables, and the model parameters are estimated by canonical correlation analysis. The proposed model is applied to daily rainfall series at Seoul station having 46 years data from 1961 to 2006. The model shows a capability to reproduce daily and seasonal characteristics simultaneously. Therefore, the proposed model can be used as a short or mid-term prediction tool if elaborate GCM forecasts are used as a predictor. Also, the nonstationary Markov chain model can be applied to climate change studies if GCM based climate change scenarios are provided as inputs.

• Journal of Science Education
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• v.45 no.3
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• pp.336-348
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• 2021

The goal of this study is to investigate the current status of implementation of convergence education in elementary, middle, and high schools. A survey was conducted on 871 in-service teachers nationwide, and frequency analysis was conducted by school level. Key findings are as follows: first, 449 (51.5%) are found to practice convergence education. Second, the reason for implementing convergence education is the voluntary effort of teachers and the educational necessity for the future society. Third, it was found that convergence education is being implemented centered on science, arts, and social studies as a link between subjects in regular curriculum hours. Fourth, 270 (64%) of teachers who implemented convergence education in response to COVID-19 performed online convergence education, and experienced difficulties in creating class materials and communicating with students. Fifth, the excessive work of teachers, insufficient support for teacher training and research group activities, and lack of various convergence education programs are suggested as reasons for not implementing convergence education. This study hopes to provide implications for policy and implementation for revitalizing convergence education.

• The Korean Journal of Pain
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• v.36 no.1
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• pp.113-127
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• 2023

Background: Resting-state functional connectivity (rs-FC) may aid in understanding the link between painmodulating brain regions and the descending pain modulatory system (DPMS) in fibromyalgia (FM). This study investigated whether the differences in rs-FC of the primary somatosensory cortex in responders and non-responders to the conditioned pain modulation test (CPM-test) are related to pain, sleep quality, central sensitization, and the impact of FM on quality of life. Methods: This cross-sectional study included 33 females with FM. rs-FC was assessed by functional magnetic resonance imaging. Change in the numerical pain scale during the CPM-test assessed the DPMS function. Subjects were classified either as non-responders (i.e., DPMS dysfunction, n = 13) or responders (n = 20) to CPM-test. A generalized linear model (GLM) and a receiver operating characteristic (ROC) curve analysis were performed to check the accuracy of the rs-FC to differentiate each group. Results: Non-responders showed a decreased rs-FC between the left somatosensory cortex (S1) and the periaqueductal gray (PAG) (P < 0.001). The GLM analysis revealed that the S1-PAG rs-FC in the left-brain hemisphere was positively correlated with a central sensitization symptom and negatively correlated with sleep quality and pain scores. ROC curve analysis showed that left S1-PAG rs-FC offers a sensitivity and specificity of 85% or higher (area under the curve, 0.78, 95% confidence interval, 0.63-0.94) to discriminate who does/does not respond to the CPM-test. Conclusions: These results support using the rs-FC patterns in the left S1-PAG as a marker for predicting CPM-test response, which may aid in treatment individualization in FM patients.

• Information Systems Review
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• v.10 no.3
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• pp.65-87
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• 2008

Knowledge management is an innovation paradigm to improve organizations competitiveness by strengthening organization's knowledge competency. Most organizations which have implemented knowledge management have experienced various difficulties in improving organization's knowledge competency, and so they have strived to find solutions. For the problems, it may be considered as an effective approach to link between knowledge management and human resource development. This study introduces two real cases adopting such approach focusing on competency development and career development which are primary areas of human resource development, and presents a model structuring core mechanisms which can be found in the cases. The model focuses on creating synergy effects between knowledge management and workforces' competency development. The cases and the model are expected to be helpful in enhancing organizational competency and the performance of knowledge management.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.443-461
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• 2014

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. For one-hop overlay source routing, when a given primary path suffers from the link failure or performance degradation, the source can reroute the traffic to the destination via a strategically placed relay node. However, the over-heavy traffic passing through the same relay node may cause frequent package loss and delay jitter, which can degrade the throughput and utilization of the network. To overcome this problem, we propose a Load-Balanced One-hop Overlay Multipath Routing algorithm (LB-OOMR), in which the traffic is first split at the source edge nodes and then transmitted along multiple one-hop overlay paths. In order to determine an optimal split ratio for the traffic, we formulate the problem as a linear programming (LP) formulation, whose goal is to minimize the worse-case network congestion ratio. Since it is difficult to solve this LP problem in practical time, a heuristic algorithm is introduced to select the relay nodes for constructing the disjoint one-hop overlay paths, which greatly reduces the computational complexity of the LP algorithm. Simulations based on a real ISP network and a synthetic Internet topology show that our proposed algorithm can reduce the network congestion ratio dramatically, and achieve high-quality overlay routing service.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.209-215
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• 2006

Now, in this paper, going to present you with an Idea related to a new inverter of multi-step voltage source, that Is, the double-connected 12-step inverter with an auxiliary circuit. It possibly can be 24-step inverter with 3-phase voltage source which will enable us make full application even to medium and high power-level Motor drive, UPS, STATCOM, SVC, etc. in which the PWM method could not be employed. 24-step operation can be obtained from the link between the existing 12-step inverter and the additional auxiliary circuit in which the transformer of auxiliary circuit generates ripple voltage delivered to the inverter. Through a lot of experiments and simulations, (from which the validity of this scheme is confirmed,) we came to the conclusion that the increase of the primary winding number on transformer by 2N(N=1,2,3....) leads to the 12M-step(M=2,3,4...) inverter. The validity of the proposed scheme is confirmed by the simulated and experimental results.

• The Research Journal of the Costume Culture
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• v.7 no.2
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• pp.230-241
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• 1999

The purpose of this study is to classify frequency of advertisement and types of advertisement by items and to analyze a primary factors were factors were reflected in the costumes by a policy of rule under the Japanese rule. Data was MaIl Shin Bo\`s advertisement connected with costumes from 1910 to 1945 years. The results are as follows : 1. The order of the advertisement\`s frequency was footwear, cosmetics, soap[, headgear, western style clothes, precious metals and so on. 2. The type of the advertisement was a format that transmits informs in all items. Cosmetics, hairdye and shampoo applied positive appeals. 3. In the military government, the advertisement\`s frequency connected with costumes was 37.5% and a shoe store was the first order. A shoes and headgear were high level, because of these were essential imports and were allowded as a proper articles for a western style clothes by a civilized policy. In the political periods of civilization, the advertisement\`s frequency connected with costumes was 54%. This result indicates industrial development of this period. Soap was the first order during 1924∼1933 and cosmetics was the first order during 1934∼1940. High level of the advertisement\`s frequency in these imports were reflected by a cultural policy as a link of an appeasement measure In the political periods of a racial liquidation, the advertisement\`s frequency connected with costumes was 8.5% and the advertisement\`s order by items was cosmetics, a shoe store. The reason was that reflected the phases of the times that was serious by a shortage of goods and an reinforcement of wartime\`s attitudes throughout war.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.121-126
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• 2013

Cycloconverter used as a power conversion device in the speed and torque control system of AC machines has the advantage of a simple control and a large torque at low speed. In addition, because a rectifier, a DC link, and an inverter are not installed, this system is simple and suitable for large power system. If a power conversion device, which is currently used as a propulsion motor of large vessel, is changed into cycloconverter, the system is simplified and then the installation costs can be significantly reduced. However, conventional cycloconverter has the increased harmonics because the power loss is large and the waveform of output voltage is distorted, due to the high-speed switching of power semiconductor devices. In order to improve these shortcomings, this paper describes a phase shifting filter which is composed of two inputs with different phases in the primary side and one output in the secondary one. As the voltage waveforms with two different phases are added and transformed into the secondary side, these outputs are close to sinusoidal waves. Thereby the voltage waveforms, which are applied to the propulsion motors, are improved and total harmonic distortions (THDs) are significantly reduced.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.255-258
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• 1996

Eight 2-day-old SPF Chickens were each inoculated Orally With 3 Sing1e dose Of 5 × 105 oocysts of Cryptosporinium boilevi. and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. bcileyi IgG antibody levels remained high (1 : 106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 × 107 oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles. but did not exhibit any oocyst shedding before or after experimental reinfection.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.23-30
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• 2008

The relationship between three phenological parameters and somatic embryogenesis was investigated during a two-year period. Staminodes and petals from six hybrids and two clones as controls were sowed on three distinct primary callus growth media. Flowering level, fructification level, and leaf thrusts rhythm as phenological parameters were measured simultaneously during the weekly harvest of flower buds. Mean and coefficient of variation of the measured parameters highlighted stable phenological phases. The relationship between phenological parameters and somatic embryogenesis was investigated first by comparing the variation of somatic embryogenesis and that of the phenological parameters, and second by using Pearson's linear correlation. Except for the fructification level in both control clones the first year, the other parameters recorded stable phenological phases, regardless of the genotype and year. Favorable and unfavorable phases for the somatic embryogenesis were identified. In hybrids, favorable phases included February, August, September, and October. In both control clones, time interval propitious to embryogenesis stretched from February to December. The significance of the coefficient of correlation seemed to establish a relationship between somatic embryogenesis and phenology. However, a causal link could not be established. Leaf thrusts rhythm was revealed to be the phenological parameter most linked to somatic embryogenesis. Attempts to optimize embryogenesis during unfavorable phases, showed that a correction of 2.4 D/TDZ concentration is not the solution.