• 대한공업교육학회지
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• v.40 no.2
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• pp.44-71
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• 2015

This study is aimed to analyze the cognitive level of basic job skill for students, graduates, and teachers in a specialized high school, as well as for workers in a company, and to suggest an optimal educational curriculum by deciding the priority of the basic job skill in education in the field of mechanic, electric electronic semiconductor, and architecture civil engineering construction. This research was undertaken with the use of various statistic skills, the Borich method, and the locus for focus model. Also, this research shall be valued in synthetic understandings for curriculum revising. The educational priority which shall be applied to the mechanic, electric electronic semiconductor, and architecture civil engineering construction at specialized high school was analyzed, and according to this, a new curriculum was suggested. For mechanic, it put its educational priority on Expressing oneself, Problem solving, Self-development, Career development, Managing time, Negotiation, and Understanding technology. For electric electronic semiconductor, its focus was on Managing time, and for architecture civil engineering construction, they emphasized Problem solving, Self-development, Career development, Managing time, and Conflict management.

• Analytical Science and Technology
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• v.17 no.6
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• pp.454-463
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• 2004

The sorption behavior of some metal ions on XAD-16-CTA chelating resin was investigated by batch method. The sorption of chelating resin was highly selective for Hf(IV), Zr(IV) and Th(IV) at pH 3.0 ~ 6.0 and the maximum sorption capacity of Zr(IV) ion was 0.81 mmol/g. It was successfully applied to the separation of several rare metal ions from mixed metal solutions by using CDTA, EDTA, NTA and $NH_4F$ as masking agent. The elution order of metal ions obtained from breakthrough capacity and the overall capacity at pH 4.0 was Zr(IV)>Th(IV)>Hf(IV)>U(VI)>Cu(II)>In(III)>Pb(II). Desorption characteristics for metal ions was investigated with desorption agents such as HCl, $HNO_3$, $HClO_4$. 2 M HCl showed high desorption efficiency. Th(IV) ion can be successfully separated from mixed metal ions by using XAD-16-CTA cheating resin.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.457-463
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• 2015

A gas turbine engine plays an important role as a prime mover that is used in the marine transportation field as well as the space/aviation and power plant fields. However, it has a complicated structure and there is a time delay element in the combustion process. Therefore, an elaborate mathematical model needs to be developed to control a gas turbine engine. In this study, a modeling technique for a gas generator, a PLA actuator, and a metering valve, which are major components of a gas turbine engine, is explained. In addition, sub-models are obtained at several operating points in a steady state based on the trial running data of a gas turbine engine, and a method for controlling the engine speed is proposed by designing an NPID controller for each sub-model. The proposed NPID controller uses three kinds of gains that are implemented with a nonlinear function. The parameters of the NPID controller are tuned using real-coded genetic algorithms in terms of minimizing the objective function. The validity of the proposed method is examined by applying to a gas turbine engine and by conducting a simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.3-11
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• 2015

An advanced receiver which can manage inter-cell interference is required to cope with the explosively increasing mobile data traffic. 3rd Generation Partnership Project (3GPP) has discussed network assisted interference cancellation and suppression (NAICS) to improve signal-to-noise-plus-interference ratio (SINR) and receiver performance by suppression or cancellation of interference signal from inter-cells. In this paper, we propose the advanced receiver based on soft decision to reduce the interference from neighbor cell in LTE-Advanced downlink system. The proposed receiver can suppress and cancel the interference by calculating the unbiased estimation value of interference signal using minimum mean square error (MMSE) or interference rejection combing (IRC) receiver. The interference signal is updated using soft information expressed by log-likelihood ratio (LLR). We perform the system level simulation based on 20MHz bandwidth of 3GPP LTE-Advanced downlink system. Simulation results show that the proposed receiver can improve SINR, throughput, and spectral efficiency of conventional system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.415-421
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• 2018

The Republic of Korea has a more rapidly aging society than any other country in the world. In order to prepare for the attendant challenges, this research provides basic data for policies related to aging ship officers, analyzing the relationship between elderly ship officers and marine accidents. The data used here spans 11 years, from 2006 to 2016, and the survey and regression analysis were conducted only on ship officers, excluding crew. As a result of this research, first, it was found that the number of employed ship officers older than 60 has increased 2.7 times over the past 11 years and the range of this increase was larger than for other age categories. Second, the number of elderly ship officers disciplined for marine accidents increased by around 2.6 times. Third, elderly ship officers had around 1.5 times the rate of marine accidents compared to non-elderly ship officers. Fourth, as a result of conducting regression analysis between the number of employed elderly ship officers and the number of officers disciplined, the degree of explanatory power of elderly ship officers for disciplined officials was 75.1%. Since our society will age quickly, policies such as license renewal education for elderly ship officers and regulation enforcing the quality of renewal will be needed.

• Elastomers and Composites
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• v.38 no.3
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• pp.262-272
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• 2003

Maleic anhydride-grafted-polypropylene(PP-g-MA) were used as a blend component and a compatibilizer, respectively, for two reactive blends of polyamide 66(PA 66)PP-g-MA binary blends and PA 66/polypropylene(PP)/PP-g-MA ternary blends. The goal of this work was to investigate the property differences between binary and ternary blends. Tensile strength, flexural modulus, heat deflection temperature, impact strength, melt flow index, and the dependence of melt viscosity on the shear rate were examined. The impact strengths of binary blends were higher than those of ternary blends at all compositions, since the in situ synthesis of PP-g-PA 66 copolymer through the imide formation between the amine end group of PA 66 and the anhydride group of PP-g-MA gave the increase of molecular weight and was more popular in binary blends than in ternary blends. In case of ternary blends, most of the properties were superior to those of binary blends, owing to the better properties of PP compared with PP-g-MA. The toughened binary blends with 70/30(PA 66/PP-g-MA) and 80/20 ratios were not commercially applicable due to their poor processibility. So, the ternary blends which showed lower melt viscosities were recommended for the commercial applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.264-277
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• 2018

Focusing on the potential impact of information and communication technology (ICT) on older adults' quality of life, this study empirically examined the influence of smartphone use in old age on life satisfaction, depression, social activity and social support of Korean older adults. In order to examine the effects of smartphone use, this study analyzed data from 630 questionnaire surveys from older adults aged 65 and over living in Seoul. The effects of smartphone use were tested using hierarchical multiple regression analysis, controlling for socio-demographic variables such as age, sex, spouse, education and income. Results showed that the effects of smartphone use on life satisfaction, depression and social activity of older adults were statistically significant. However, the effects of smartphone use on social support of older adults was not statistically significant. This study suggests that ICT such as smartphones in old age plays generally positive roles in enhancing psychological, mental and social aspects of quality of life. This implies that further practical efforts to expand the distribution and use of ICT in old age are required to improve quality of life and successful aging of older adults.

• Research in Plant Disease
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• v.26 no.4
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• pp.239-249
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• 2020

To find out the cause of the fire blight outbreak in apples and pears of Korea in 2019, we investigated disease appearing situation of thirty fire blight infected orchards, and interviewed farmers to determine the cultivation characteristics. Fire blight occurred mostly in orchards that had infected more than 2 years before. The cause of this were as follows: farmers did not know the symptoms of the disease properly. It is presumed that it has spread from the first occurrence to the surrounding orchards by flower-visiting insects or farmers and to a short distance or a long distance by the same cultivator or co-farmer. These series of processes repeated in the newly spreading area, and then disease reports increased as farmers became aware of fire blight. To minimize the spread of fire blight in Korea, it suggested that thorough education of farmers for early diagnosis and quantitative detection technology that can diagnose even in no symptom showing plants. And chemical or biological spraying systems suitable for domestic cultivation methods, which are producing large fruits, and molecular epidemiological studies of pathogens.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.113-126
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• 2021

The future energy consumption pattern will show a very different pattern from the present due to the increase of distributed power sources such as renewable energy and the birth of the concept of prosumers, etc. Accordingly, it can be predicted that the direction of establishment of an appropriate production and supply plan considering the stability and consumption efficiency of the entire power grid will also be different from now. This paper proposes a simulation model that can test a new operational strategy when faced with a number of possible future environments. Through the proposed model, it is possible to simulate and analyze power consumed and supplied in a future Smart Grid environment, in which a large amount of new concepts including energy storage service (ESS) and distributed energy resources (DER) will be added. In particular, it is possible to model complex systems structurally by using DEVS formalism among the ABM (Agent-Based Model) methodologies that can model decision-making for each agent existing in the grid, and several factors can be easily added to the grid. The simulation model was verified using given dataset in the current situation, and scenario analysis was performed by simply adding an ESS, one of the main elements of the smart grid, to the model.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.219-230
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• 2022

This study aims to evaluate the effect of sleep duration on obesity in Korean adult using data from the 8th Korea National Health And Nutrition Examination Survey in 2019. The study subjects were 5,213, and we performed frequency analysis, descriptive statistics, and multivariate regression analysis using the SPSS Win 27.0 program. The average sleep duration of the subjects was 6.8 hours per day, and the average body mass index (BMI) was 23.9 kg/m². As a result of bivariate analysis of factors affecting sleep duration, age, education level, stress, depression, diabetes, hypertension, and arthritis were significantly associated with sleep duration. The body mass index (BMI) of the group with less than 6 hours of sleep duration was 24.4, which was higher than that of other groups, and there was a significant negative correlation between sleep duration and BMI (B=-0.247; 95% CI=-0.334~ -0.160). In conclusion, in order to prevent obesity in adults, various efforts from the country and local communities are needed to increase sleep duration.