• Composites Research
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• v.12 no.4
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• pp.42-54
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• 1999

FMLC(Fiber-Metal Laminate Composites) is a new structural material combining thin metal laminate with adhesive fiber prepreg, it nearly include all the advantage of metallic materials, for example: good plasticity, impact resistance, processibility, light weight and excellent fatigue properties. This research studied the optimum design of the FMLC subject to various loading conditions using genetic algorithm. The finite element method based on the shear deformation theory was used for the analysis of FMLC. Tasi-Hill failure criterion and Miser yield criterion were taken as fitness functions of the fiber prepreg and the metal laminate, respectively. The design variables were fiber orientation angles. In genetic algorithm, the tournament selection and the uniform crossover method were used. The elitist model was also used to be effective evolution strategy and the creeping random search method was adopted in order to approach a solution with high accuracy. Optimization results were given for various loading conditions and compared with CFRP(Carbon Fiber Reinforced Plastic). The results show that the FMLC is more excellent than the CFRP in point and uniform loading conditions and it is more stable to unexpected loading because the deviation of failure index is smaller than that of CFRP.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.339-362
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• 2018

In this paper, we simulate the contribution of an increasing renewable energy to demands for fossil fuels and power supply price by estimating a cost function for the Korean electric power generation sector. Since the renewable energy is a composite input, it is not feasible to compute the price index for renewable energy due to data limit. We estimate a restricted cost function, which is derived by minimizing the costs of fossil fuels conditional on the quantity of renewable energy set to its optimal level, jointly with supply relation. In particular, derivation of the shadow price of renewable energy would make it possible to analyze potential costs incurred by power plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.637-643
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• 2017

This study analyzed the Quality of Accounting Earning of Investor Relations(IR). For this, we utilized Book-Tax Difference Variability as the proxy of the level of the Quality of Accounting Earning. This study used 2,106 sample data from 2011 to 2016 on the listed firm on KOSPI(Korea Composite Stock Price Index). In short, the study results are as follows. Investor Relation(IR) has a negative relevance with Book-Tax Difference Variability, which agreed with the result of additional analysis using extra sample. According to these results, we can expect that Investor Relations(IR) firms will report more faithful Accounting Earning. This study makes the following fresh contribution to the field. The study result confirms how Investor Relation(IR) affects the Quality of Accounting Earning. We hope that this study will help the development of capital market.

• The korean journal of orthodontics
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• v.41 no.2
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• pp.121-126
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• 2011

Objective: The purpose of this study was to evaluate shear bond strength (SBS) and failure site location of brackets bonded to enamel with or without desensitizer application. Methods: Sixty-six freshly extracted human premolar teeth were randomly divided into 3 groups of 22. Group 1 served as the control. Desensitizer was applied to the remaining teeth at two time intervals (Group 2, bonded immediately after Pro-$Relief^{TM}$ (Colgate-Palmolive Co., New York, NY, USA) application and Group 3, bonded 30 days after Pro-$Relief^{TM}$ application with the teeth stored in artificial saliva during the 30 days). Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, the SBS of the brackets was tested using a universal testing device. Adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance, Tukey's HSD, and G tests. Results: The SBS was significantly lower in Group 2 than in Groups 1 (p = 0.024) and 3 (p = 0.017). Groups 1 and Group 3 did not differ (p = 0.991). ARI scores did not differ significantly among groups. Conclusions: The Pro-$Relief^{TM}$ desensitizer agent applied immediately before bonding significantly reduces bond strength, but the SBS values still exceed the minimum 5.9 - 7.8 MPa required for adequate clinical performance. Immersing the teeth in artificial saliva for 30 days after applying the Pro-$Relief^{TM}$ desensitizer agent and before bonding increased the SBS to control levels.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.267-276
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• 2018

The purpose of the study was to provide basic data for planning and offering nursing intervention to prevent suicide attempts by identifying the factors influencing the suicidal thoughts of depressed adults. The subjects of this study were 1,202 individuals who answered clearly in 2013-2015 National Health and Nutrition Survey. A composite sample plan file was generated using the IBM SPSS 23.0 program, and then the data were weighted and analyzed. Suicidal ideation was influenced by income (50-60s), number of family members (50-60s), marital status (40-50s), subjective health (30-50s, over 70s), stress (30s, over 50s), economic activity status (50s), diabetes (60s or older), alcohol consumption (60s), and Body Mass Index (BMI) (40s). These results suggest that tailor-made interventions for the prevention of suicide need to take into account the general and health-related factors of the subjects.

• Journal of the Korean Home Economics Association
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• v.25 no.3
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• pp.15-26
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• 1987

The purpose of this study was to develop the pattern drafting method which would be suitable to their physical characteristics for the fatty body of 40∼55 aged Korean women who are more than 1.5 Rohrer's Index and 90㎝ bust girth. The study was composed as follows; 1. Body measurement and statistical analysis: One hundred and thirty women were measured on 29 items. Thirty-four items including 29 measured items and 5 calcutated items were analyzed statistically. 1) Mean, standard deviation, variance, maximum, minimum, range were computed. 2) Correlation coefficients between each items were computed. 2. Development of new bodice pattern drafting method: Measurement items necessary to draft new bodice pattern were bust girth, center back waist length, shoulder width, back width, chest and neck base girth. The new pattern was examined through three wearing tests for completion. 3. Evaluation of the new pattern drafting method: The new pattern was objectively evaluated by the sensory test. The sensory evaluation was applied to evaluate the new pattern for the fatty body women by comparint it with the conventional patterns. The results of sensory tests of the new pattern are as follows: 1) The composite reliability coefficient is 0.7698, and the reliability of sensory test shows high. 2) According to a statistical analysis of the result of the 23 items on the questionaire, all the items showed significant differences(α 0.01) between the two, with the new pattern having higher scores. The new pattern is better conventional pattern as the average mark of the former is 3.901 but that of latter is 2.926. The new pattern drafting method proved to be superior to the conventional one especially in the fitness at the center front neck point, shoulder point, side line, armscye depth, position of bust point, chest width line, under arm dart and the shoulder line.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1107-1114
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• 1999

In this paper, we analyze the effect of co-channel interferers coming from other systems with composite log-normal shadowing and Nakagami fading on the capacity of the imperfect power-controlled DS/CDMA cellular system. The analytical results are compared with the results of Prasad and Jansen in which they derive the result under the condition of imperfect power-control of DS/CDMA system and without considering interference. And the outage probability is calculated fro the effect of the log-normal/Nakagami faded inferers on DS/CDMA system using Schwartz and Yeh's method. With the deviation of outage probability, we analyzed the decreases in the capacity of DS/CDMA system with the variation of the paramenters of the imperfect power-control, the fadig index, the processing gain, the power ratio, the voice activity factor, and the number of interferers. Analysis reuslts have shown that the capacity of DS/CDMA system is very sensitive to the imperfect power-control and the number of interferers. It is shown that the DS/CDMA system capacity decreased according to increase of the deviation of the impertect power-control, the increase of the fading, and the increase of interferer number.

• Structural Engineering and Mechanics
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• v.22 no.6
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• pp.665-683
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• 2006

The strength behaviors of Fiber Reinforced Plastics (FRP) Composites can be greatly influenced by the properties of constitutive materials, the laminate structures, and load conditions etc, accompanied by many uncertainty factors. So the reliability study on FRP is an important subject of research. Many achievements have been made in reliability studies based on the probability theory, but little has been done on the roles played by fuzzy variables. In this paper, a fuzzy reliability model for FRP laminates is established first, in which the loads are considered as random variables and the strengths as fuzzy variables. Then a numerical model is developed to assess the fuzzy reliability. The Monte Carlo simulation method is utilized to compute the reliability of laminas under the maximum stress criterion. In the second part of this paper, a generalized fuzzy reliability model (GFRM) is proposed. By virtue of the fact that there may exist a series of states between the failure state and the function state, a fuzzy assumption for the structure state together with the probabilistic assumption for strength parameters is adopted to construct the GFRM of composite materials. By defining a generalized limit state function, the problem is converted to the conventional reliability formula that enables the first-order reliability method (FORM) applicable in calculating the reliability index. Several examples are worked out to show the validity of the models and the efficiency of the methods proposed in this paper. The parameter sensitivity analysis shows that some of the mean values of the strength parameters have great influence on the laminated composites' reliability. The differences resulting from the application of different failure criteria and different fuzzy assumptions are also discussed. It is concluded that the GFRM is feasible to use, and can provide an effective and synthetic method to evaluate the reliability of a system with different types of uncertainty factors.

• Journal of IKEEE
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• v.24 no.2
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• pp.453-460
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• 2020

This paper, UHF band integrated communication antenna for ship communication is designed as a flat type that can be mounted on the integrated mast among integrated communication antennas such as integrated communication, ship communication, broadcasting, and telephone of the ship. The unified mast mounted antenna is an integrated communication antenna applied to the Navy's KDDX, which is an optimized type of integrated communication antenna including a 'composite slope' structure including operational capability, survivability, and improved operability and maintainability. The existing rotary radar and a plurality of monopole-type communication antennas were changed from an irregularly attached shape to the mast exterior to an integrated mast shape including a flat-type integrated communication antenna. the radar reflection area index (RCS) is significantly lowered and compared to overseas products. The goal is to develop a gain broadband antenna.

• Journal of Korean Biological Nursing Science
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• v.19 no.1
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• pp.48-54
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• 2017

Purpose: This study was done to identify the influence of severity of drinking problem, circadian rhythm and sleep quality in patients with alcohol use. Methods: A descriptive study design was utilized. Data were collected using self-report questionnaires from 139 patients with alcohol use disorder who were admitted to a psychiatric hospital in D city, Korea. The questionnaires included Alcohol Use Disorders Identification Test (AUDIT), Composite Scale of Morningness (CMS), Pittsburgh Sleep Quality Index (PSQI), and Korea sleep scale A. Data were analyzed using descriptive statistics, Pearson's correlation coefficients, and multiple regressions using the SPSS 20.0 program. Results: There was significant correlations among severity of problem drinking, circadian rhythm, sleep quality and sleep disorder. The significant factors influencing sleep disorder were severity of problem drinking(${\beta}=.12$, p= .042), circadian rhythm(${\beta}=-.14$, p= .039) and sleep quality(${\beta}=.63$, p= < .001). This model explained 56% of variance in sleep disorder(F = 57.34, p= < .001). Conclusion: The results of this study suggest that the development of sleep intervention programs for alcohol use disorder patients needs to consider severity of alcohol use, circadian rhythm and sleep quality, and sleep assessment and intervention are needed the early stage of the treatment and recovery process.