• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.266-273
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• 2016

Two-dimensional hydraulic experiments were performed to assess the impact of artificial seaweed on wave energy attenuation, and coastal erosion prevention. In this experimental study, erosion geometry and wave reflection coefficients were determined for normal and stormy incident waves, with and without artificial seaweed. The coastline of beaches without artificial vegetation was observed to retreat, and the longshore bar height increased in normal and stormy conditions. Through the introduction of artificial seaweed (of widths 0.8 m, and 1.6 m), the coastline was found to advance in the offshore direction due to material deposition. From these results, it is shown that artificial seaweed alters the cross-section of beaches, such that it is possible to prevent coastline erosion.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.30-37
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• 2008

Dynamic excitation and response analysis is an acceptable method to determine some of physical properties of agricultural product for quality evaluation. There is a difference in the internal viscoelasticity between sound and defective fruits due to the difference of geometric structures, thereby showing different vibration characteristics. This study was carried out to develop a portable piezoelectric film-based glove sensor system that can separate internally damaged watermelons from sound ones using an acoustic impulse response technique. Two piezoelectric sensors based on polyvinylidene fluoride (PVDF) films to measure an impact force and vibration response were separately mounted on each glove. Various signal parameters including number of peaks, energy ratio, standard deviation of peak to peak distance, zero-crossing rate, and integral value of peaks were examined to develop a regression-estimated model. When using SMLR (Stepwise Multiple Linear Regression) analysis in SAS, three parameters, i.e., zeros value, number of peaks, and standard deviation of peaks were selected as usable factors with a coefficient of determination ($r^2$) of 0.92 and a standard error of calibration (SEC) of 0.15. In the validation tests using twenty watermelon samples (sound 9, defective 11), the developed model provided good capability showing a classification accuracy of 95%.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.3
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• pp.408-415
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• 2020

Objective: The aim of the paper was to compare the fit of data derived from daily automatic milking systems (AMS) and monthly test-day records with the use of lactation curves; data was analysed separately for primiparas and multiparas. Methods: The study was carried out on three Polish Holstein-Friesians (PHF) dairy herds. The farms were equipped with an automatic milking system which provided information on milking performance throughout lactation. Once a month cows were also subjected to test-day milkings (method A4). Most studies described in the literature are based on test-day data; therefore, we aimed to compare models based on both test-day and AMS data to determine which mathematical model (Wood or Wilmink) would be the better fit. Results: Results show that lactation curves constructed from data derived from the AMS were better adjusted to the actual milk yield (MY) data regardless of the lactation number and model. Also, we found that the Wilmink model may be a better fit for modelling the lactation curve of PHF cows milked by an AMS as it had the lowest values of Akaike information criterion, Bayesian information criterion, mean square error, the highest coefficient of determination values, and was more accurate in estimating MY than the Wood model. Although both models underestimated peak MY, mean, and total MY, the Wilmink model was closer to the real values. Conclusion: Models of lactation curves may have an economic impact and may be helpful in terms of herd management and decision-making as they assist in forecasting MY at any moment of lactation. Also, data obtained from modelling can help with monitoring milk performance of each cow, diet planning, as well as monitoring the health of the cow.

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.127-137
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• 2017

This study aims to identify the awareness and performance level of hospital infection control in medical technicians working in small and medium-sized hospitals. The experiment was conducted in 235 medical technicians (medical laboratory technologist, radiological technologist, and physical therapist), and for statistical processing, SPSS Ver.23.0 was used to conduct mean and standard deviation, analysis of variance, and regression analysis. As a result, it was found that the major cause of improper infection control was lack of experts ($3.17{\pm}1.18$) and performance level was statistically significantly lower than awareness of infection control. "I took no measures after infection accident" was responded the highest at 40.0%(94 persons), and in "I reported to the head of department after disinfection, examination, and/or vaccination," the standardized regression coefficient ${\beta}$ was -0.265, p=0.025, which suggested that there was a significant negative (-) impact. Infection control level showed a significant positive correlation with training and infection control instructions. Therefore, it was found that medical technicians in small and medium-sized hospitals required high skilled manpower in infection control, training, infection control instructions, etc. Through this study, more effective infection control is considered to be possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2750-2757
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• 2010

Recently, there have been a number of voices from industry that automotive education at the college is too theoretical and so college graduates are lack of practical ability to apply the automotive idea to actual systems. In order to educate engineering students design qualities in creative problem solving, this paper reports the results of employing engineering design projects in a Motor sports course of at A College. This paper presents design creterion and manufacture process of $CO_2$ model dragster, measures $CO_2$ model dragster speed and aerodynamic drag. In order to investigate the impact of engineering design on student's learning, a survey was conducted in 2008 spring semester. According to the results of survey analyses, student's key competencies and satisfaction reports high values on engineering design projects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3665-3671
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• 2013

This study was investigate to impact on safety accidents occurrence for the safety practices of middle school students learn the extent of the failure. A total of 292 patients and it survey data were collected from 5 November 2012 to 11 May 25 of research subjects. Research tools were used SPSS win17.0, the mean and standard deviation, Paired t-test, Pearson's correlation coefficient was used. Safey practice and cognitive failure of subjects was related to negative correlation and according as safety practices was higher, cognitive failure was low. According as safety practices and cognitive failure was low, Safety incidents experienced was high. Therefore, by applying safety practices and cognitive failure degree, it need to for research to come up with ways for the prevention of safety accidents. Besides, A variety of safety and accident prevention training programs by expanding the scope of the study in school, it should be done generalization of safety awareness, cultivate and Safety practice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.572-578
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• 2017

Haptic systems help users feel a realistic sensation when they manipulate virtual objects in the remote virtual environment. However, there are communication time delays that may make the haptic system unstable. This paper shows the relationship between communication time delay, properties of a haptic device, and the stability of the haptic system with the first-order hold method in a simulation. The maximum available stiffness of a virtual spring with the first-order hold method is larger than in the zero-order hold method when there is no time delay. However, when the communication time delay is much larger than the sampling time, the maximum available stiffness to guarantee the stability becomes the same, irrespective of the sample-hold methods. Besides, the maximum available stiffness increases in inverse proportion to the communication time delay and in proportional to the damping coefficient of the haptic device.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.4
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• pp.519-526
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• 2002

In this paper, a microstrip patch array antenna for a Doppler radar at 10.525GHz is desinged and fabricated. To be used for mobile radar system, the antenna is fabricated on a single layer laminate to resist a fire impact and is covered with the Teflon foam. To obtain the desired characteristics, the array antenna is designed 4$\times$8 array using a corporate 3-dB amplitude taper. Also, using square patch elements, the antenna can be converted to a circular polarized antenna later. The designed and fabricated array antenna has the reflection coefficient$({S_11})$ -53.498dB, the horizontal beam width of $10^{\circ}$, the vertical beam width of $18.8^{\circ}$, the gain of 21dBi, the bandwidth of 220MHz for VSWR<1.5 and a side lobe level of less than -17.5dB.

• Journal of the Korean Society of School Health
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• v.31 no.1
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• pp.18-28
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• 2018

Purpose: The purpose of this study was to investigate the factors that influence ego-resilience among adolescents who have experienced abuse by parents in South Korea. Methods: This correlational study used the 4th year cross-sectional data of the seventh-grade middle school students who participated in the Korean Children and Youth Panel Survey (KCYPS) in fourth grade. Data analysis was performed by using SPSS/WIN 23.0 program, which included descriptive statistics, Pearson's correlations coefficient, and hierarchical regression. Results: The results of the hierarchical regression of model 5 revealed that the quality of peer relations played the most significant role in predicting ego-resilience of abused adolescents, followed by self-identity. Also, self-esteem, the quality of teacher-student relationships, excessive expectations from parents, and community awareness had a significant impact on the variance of self-resilience in abused adolescents. This regression model explained 42% of the variance. Conclusion: This study showed that ego-resilience, an asset and resource to help adolescents overcome adverse effects of abuse, was influenced by social environment as well as individual factors. In addition, social support from peers and teachers had greater influence on ego-resilience than support from family members. Thus, the factors identified in this study need to be considered in programs designed to improve ego-resilience as well as in policies for abused adolescents.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.61-67
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• 2020

In this paper, we calculated the warpage of bare substrates and chip attached substrates by using FEM (Finite Element Method), and compared and analyzed the effect of the chips' attachment on warpage. Also, the effects of layer thickness of substrates for reducing warpage were analyzed and the conditions of layer thickness were analyzed by signal-to-noise ratio of Taguchi method. According to the analysis results, the direction of warpage pattern in substrates can change when chips are attached. Also, the warpage decreases as the difference in the CTE (coefficient of thermal expansion) between the top and bottom of the package decreases and the stiffness of the package increases after chips are loaded. In addition, according to the impact analysis of design parameters on substrates where chips are not attached, in order to reduce warpage, the inner layers of the circuit layer Cu1 and Cu4 has be controlled first, and then concentrated on the thickness of the solder resist on the bottom side and the thickness of the prepreg layer between Cu1 and Cu2.