• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.20-28
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• 2016

Curved squeal noise may result when railway vehicles run on curved tracks. Contact between the wheels and the rails causes a stick-slip phenomenon, which generates squeal noise. In order to identify the mechanism of the squeal noise systematically, a scaled test rig has been fabricated. Knowledge of the contact forces between the wheels and the rail rollers is essential for investigating the squeal noise characteristics; however, it is difficult to measure there contact force. In this study, contact forces have been calculated indirectly according to the modal behavior of the subframe that supports the rail roller and the responses at specific positions of that subframe. In order to verify the estimated contact forces, the displacements at the contact points between the wheels and rail rollers have been calculated from the estimated forces; the resulting values have been compared with the measured displacement values. The SPL at the specific location has been calculated using the estimated contact forces and this also has been compared with the SPL, measured in a semi-anechoic chamber. The comparisons in displacements and SPLs show good correlation.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.373-381
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• 2012

An automatic flow and water quality monitoring system was applied to estimate pollutant loads to an urban stream during storm events in DTV (Daeduk Techno Valley), Daejeon, Korea. The monitoring system consists of rainfall gage, ultrasonic water level meter, water quality sensors for DO, temperature, pH, conductivity, turbidity and automatic water sampler for further laboratory analysis. All data are transmitted through on-line system and the monitoring system is designed to be controlled manually in the field and remotely from laboratory computer. Flow rates were verified with field measurements during storm events and showed good agreements. Automatic sampler was used to collect real time samples and analyzed for BOD, COD, TN, TP, SS and other pollutant concentrations in the laboratory. SWMM (Storm Water Management Model) urban watershed model was applied and calibrated using the observed flow and water quality data for the study area. While flow modeling results showed good agreement for all events, water quality modeling results showed variable levels of agreement. These results indicate that current options in the SWMM model to predict pollutant build up and wash-off effects are not sufficient to satisfy modeling of all the rainfall events under study and thus need further modification. This study showed the automatic monitoring system can be used to provide data to assist further refinement of modeling accuracy. This automatic stormwater monitoring and modeling system can be used to develop basin scale water quality management strategies of urban streams in storm events.

• Resources Recycling
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• v.26 no.6
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• pp.73-83
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• 2017

Used small household appliances have a wide variety of product types and component materials, and contain high percentage of black plastics. However, they are not being recycled efficiently as conventional sensors such as near-infrared ray (NIR), etc. are not able to detect black plastic by types. In the present study, an automatic sorting system was developed based on laser-induced breakdown spectroscopy (LIBS) to promote the recycling of waste plastics. The system we developed mainly consists of sample feeder, automatic position recognition system, LIBS device, separator and control unit. By applying laser pulse on the target sample, characteristic spectral data can be obtained and analyzed by using CCD detectors. The obtained data was then treated by using a classifier, which was developed based on artificial intelligent algorithm. The separation tests on waste plastics also were carried out by using a lab-scale automatic sorting system and the test results will be discussed. The classification rate of the radial basis neural network (RBFNNs) classifier developed in this study was about > 97%. The recognition rate of the black plastic by types with the automatic sorting system was more than 94.0% and the sorting efficiency was more than 80.0%. Automatic sorting system based on LIBS technology is in its infant stage and it has a high potential for utilization in and outside Korea due to its excellent economic efficiency.

• Particle and aerosol research
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• v.13 no.2
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• pp.79-85
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• 2017

This study identified the loss of minimum fluidization velocity and pressure in accordance with the superficial velocity of $NiO/MoO_3/MoS_2$, a rare metallic oxide and high value-added material in the lab-scale fluidized bed reactor (L=0.25 m, D=0.05 m). The average pressure loss in L/D 1, 2, and 3 of $NiO/MoO_3/MoS_2$ within the scope of superficial gas velocity between 0.07 and 0.45 m/s based on the L/D 1, 2, and 3 of the specimen was shown to be 290~1952 Pa at decreasing flux and 253~1925 Pa at increasing flux. The comparison between the theoretical value proposed by Wen and the test data showed a difference between 0.021~0.36 magnification. Based on these results, this study was able to determine the operation conditions where rare metallic oxides could be applied in real phenomena.

• Applied Microscopy
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• v.36 no.1
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• pp.7-16
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• 2006

A new remote access system for a 1.3 MV high voltage electron microscope has been developed. Almost all essential functions for HVEM operation, huck as stage control, specimen tilting, TV camera selection and image recording, are successfully embedded into this prototype of the remote system. Particularly, this system permits perfect and precise operation of the goniometer and also controls the high resolution digital camera via simple Web browsers. Transmission of control signals and communication with the microscope is accomplished via the global ring network for advanced applications development (GLORIAD). This fact makes it possible to realize virtual laboratory to carry out practical national and international HVEM collaboration by using the present system

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.3
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• pp.342-351
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• 2016

This study was carried out to develop an optimized analytical method using high-performance liquid chromatography (HPLC) applied to canthaxanthin, which is not yet designated as a food colorant in Korea, as well as to perform validation and uncertainty evaluation of this method. Official methods of AOAC, UK, and Japan with HPLC-UV detection were evaluated for the analysis of canthaxanthin by comparison of linearity, resolution, selectivity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision, recovery, inter-laboratory tests, and uncertainty measurement. The calibration curves showed high linearity with an $R_2$ value of over 0.999 for canthaxanthin standard solutions in all three official methods. The official method of Japan exhibited the best results in terms of resolution and selectivity, including the lowest LOD and LOQ. The average coefficients of variation were calculated as less than five of three institutes with a precision value less than 1, accuracy near 100%, and recovery ratio between $100{\pm}10%$. The expanded uncertainty for canthaxanthin was estimated to be $39.5{\pm}5.29mg/kg$ (95% confidence level, k=2), and the uncertainty of measurement was 13.4%. In this study, official methods of canthaxanthin were compared and the validities verified. The results will be further applied to establish an authorized analytical method for canthaxanthin in Korea.

• Korean Journal of Medical Ethics
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• v.21 no.4
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• pp.330-343
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• 2018

This article explores some of the ethical issues associated with the fourth industrial revolution and suggests new directions for bioethics education in Korean universities. Some countries have recently developed guidelines and regulations based on the legal and ethical considerations of the benefits and social risks of new technologies associated with the fourth industrial revolution. Foreign universities have also created courses (both classroom and online) that deal with these issues and help to ensure that these new technologies are developed in an ethically appropriate fashion. In South Korea too there have been attempts to enhance bioethics education to meet the changing demands of society. However, bioethics education in Korea remains focused on traditional bioethical topics and largely neglects the ethical issues related to emerging technologies. Furthermore, Korean universities offer no online courses in bioethics and the classroom courses that do exist are generally treated as electives. In order to improve bioethics education in Korean universities, we suggest that (a) new course should be developed for interprofessional education; (b) courses in bioethics should be treated as required subjects gradually; (c) online courses should be prepared, and (d) universities should continually revise course contents in response to the development of new technologies.

• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.59-69
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• 2007

The aim of this study was to investigate teachers' perceptions on MBL (microcomputer-based laboratory) experiment training program for teachers, the expecting effects of MBL experiment and application of MBL experiment after conducting MBL experiment training for science classes in schools. This study showed that most of the teachers who participated in the training program thought that the MBL experiment training program was very useful and instructive. Many teachers considered that MBL experiments using a computer could decrease time spent in the experiment by accurate and fast data collection and analysis. They also thought that the reduced time could be used more effectively in the analysis of experimental data and discussion activities leading to correct concept formation as well as in the development of graphical analysis and science process skills. However, they thought that MBL experiments were ineffective in learning how to operate experiment apparatus. This study also revealed that most teachers intended to apply MBL experiments in real classrooms context right after the training course and they pointed out many obstacles in introducing MBL experiments into their classrooms such as a budget to purchase equipment, poor laboratory conditions, and few MBL experiment training opportunities. In order to apply MBL experiment into the real classrooms, further changes were suggested as follows; development of technologies to reduce unit cost of equipment for MBL experiments, production and supply of many kinds of sensors, development of MBL experiment materials, and expansion of the training program for teachers.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.1
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• pp.76-81
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• 2024

Recently, agricultural methods are changing from experience-based agriculture to data-based agriculture. Changes in agricultural production due to the 4th Industrial Revolution are largely occurring in three areas: smart sensing and monitoring, smart analysis and planning, and smart control. In order to realize open-field smart agriculture, information on the physical and chemical properties of soil is essential. Conventional physicochemical measurements are conducted in a laboratory after collecting samples, which consumes a lot of cost, labor, and time, so they are quickly measured in the field. Measurement technology that can do this is urgently needed. In addition, a soil analysis system that can be carried and moved by the measurer and used in Korea's rice fields, fields, and facility houses is needed. To solve this problem, our goal is to develop and commercialize software that can collect soil samples and analyze the information. In this study, basic soil composition measurement was conducted using soil composition measurement sensors consisting of hardness measurement and electrode sensors. Through future research, we plan to develop a system that applies soil sampling using a CCD camera, ultrasonic sensor, and sampler. Therefore, we implemented a sensor and soil analysis UI that can measure and analyze the soil condition in real time, such as hardness measurement display using a load cell and moisture, PH, and EC measurement display using conductivity.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.60-71
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• 2024

The present study aims to investigate the level difference of floor impact noises of composite floor structure using EVA resilient materials. In order to this, four different types of resilient materials were designed combining PET, PP sheet and EVA mount including Flat type, Deck type, Cavity type and Mount type. Totally 9 different samples were made for acoustic measurements which were carried out twice with bang-machine and impact ball as the heavy-weight floor impact noise sources. All the floor impact noise measurements were undertaken at the authentication institution. As a result, concerning Flat and Cavity types, it was found that 2 dB ~ 5 dB of heavy-weight floor impact noise was reduced supplementally when PET was added, while floor impact noise larger than 50 dB was acquired when single resilient material was used. Especially, most high performance was obtained for Mount type with 1st grade of light-weight floor impact noise and 2nd grade of heavy-weight floor impact noise. This is because of material property with low dense PET sound absorption materials which fill all around EVA mounts. Also, it was considered that this results are due to the sound impact absorption by the both EVA mounts and the air cavity between EVA mount and PP sheet. Also, it was found that at least 36 EVA mounts per 1m2 area of resilient panel make more noise reduction of heavy-weight floor impact noises.