• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.22-31
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• 2015

This study was carried out to monitor the current status of pesticide residues in selling agricultural products via online and assessed their safety in 2014. A total of 124 samples were purchased six times from March to August 2014 twenty online shopping malls randomly. These samples were analysed 208 pesticides by multiresidue method using a GC-ECD/NPD and a LC-MS/MS and confirmed by a GC-MSD. As a result of analysis, residual pesticides samples were 11 (8.9%) such as leek, young radish, welsh onion etc, of which 2 samples (1.6%) such as sesame bud (Chlorothalonil), artemisia (Chlorpyrifos) were violated Korea Maximum Residue limits (MRLs). 11 kinds of pesticides (19 times) were detected in 11 samples. Risk assessment evaluated human health exposure with the ratio of EDI (Estimated daily intake) to ADI (Acceptable daily intake) of pesticides detected. %ADI (the ratios of EDI to ADI) were 0.04~95.70% and some samples represented a fairly dangerous levels. In particular, Chlorothalonil in the sesame bud was shown as a significant risk close to 100% of %ADI. Accordingly, it is recommended to strengthen a safety check on agricultural products in online sales.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.127-133
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• 2002

Most structures are constantly influenced by repeated weathering phenomena and load action during a period of its utilization, and their component materials become superannuated and their design performance becomes slowly lost. Therefore, it is thought that it is necessary to develop the online monitoring system that can make a great contribution to the maintenance management and disaster prevention of the building structure by sensing any slight change of the entire structure regardless of its inside and outside. Especially, this study was intended to explain the entire system of the online structure by interpreting welded built-up H-beams, of structural steel members having many advantages in terms of the qualities of structural materials, through limit state design, and presenting the basic plan to apply it to the structure.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2344-2353
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• 2018

A coupled recursive total least squares (CRTLS) algorithm is proposed for parameter estimation of permanent magnet synchronous machines (PMSMs). TLS considers the errors of both input variables and output ones, and thus achieves more accurate estimates than standard least squares method does. The proposed algorithm consists of two recursive total least squares (RTLS) algorithms for the d-axis subsystem and q-axis subsystem respectively. The incremental singular value decomposition (SVD) for the RTLS obtained by an approximate calculation with less computation. The performance of the CRTLS is demonstrated by simulation and experimental results.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.106-114
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• 2017

This paper presents an automated subsurface micro void detection technique based on pulsed infrared thermography for inspecting epoxy molding compounds (EMC) used in electronic device packaging. Subsurface micro voids are first detected and visualized by extracting a lock-in amplitude image from raw thermal images. Binary imaging follows to achieve better visualization of subsurface micro voids. A median filter is then applied for removing sparse noise components. The performance of the proposed technique is tested using 36 EMC samples, which have subsurface (below $150{\mu}m{\sim}300{\mu}m$ from the inspection surface) micro voids ($150{\mu}m{\sim}300{\mu}m$ in diameter). The experimental results show that the subsurface micro voids can be successfully detected without causing any damage to the EMC samples, making it suitable for automated online inspection.

• Journal of Food Hygiene and Safety
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• v.37 no.1
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• pp.1-8
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• 2022

In this study, the pesticide residues in 106 commercial cereal grains were monitored from February to July 2021. For the investigation, 40 domestic and 66 imported products from large, small-to-medium sized offline and online distribution channels, were collected and analyzed by using the multiresidue method for 341 pesticides on GC/ECD, GC/NPD, GC/MSMS, UPLC/PDA, HPLC/FLD, LC/MSMS. Pesticides were detected in total of 8 samples (7.5%), of which one was from big box retailers, two from small and medium-sized distribution stores, and five from online shopping mall. Five (4.7%) samples were found to have pesticide residues greater than the maximum residue limits (MRLs). The detected pesticides in kidney beans (1 case), mung beans (6 cases), and sorghum (1 case), were MGK-264, chlorpyrifos, thiamethoxam, malathion, piperonyl butoxide, and pirimiphos-methyl. Specifically, an excessive amount of thiamethoxam was found from the imported mung bean (5 cases).

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.27-32
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• 2018

Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.73-84
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• 2011

This study represents construction progress management model based on quality inspection process in addition to cost-schedule integration. Quality inspection process cycle, resource estimate as progress measurement parameter, hierarchical structure of schedule, and inspection lots linking quality inspection to resource estimate are addressed as four main information areas. The authors established several process models to give a structure and correlations among information elements on each of these areas. Applying the process models proposed, an information system was implemented and utilized for nuclear power plant construction. It reveals that the system achieves accurate and objective progress information in near real time with significantly reduced time and effort as well as administrative efficiencies from making quality inspection process online.

• The Journal of Korean Association of Computer Education
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• v.18 no.3
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• pp.59-68
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• 2015

The purpose of this study is to analyze the learner's characteristics, and relationship between learning styles and achievements in online programming learning environment. For the analysis, after performing the inspection of learning styles of Grasha-Reichmann for 104 middle and high school students, online programming learning were performed for 12 weeks. First, according to learner's variable, boy was higher than girls in dependent learning style. Middle school student higher than high school student in competitive and avoid learning styles. Independent and participant learning styles show a significant difference in achievement level. Analysis of the relationship between learning styles and achievements show that independent(r=.253, p<.01) and participant(r=.303, p<.01) have the positive correlations. As a result, independent and participant learning styles are confirmed to be related with achievements. In addition, we analyzed each learning style characteristics by writing survey of the impression of the learners by main learning styles, through which we could derive teaching and learning strategies for the online programming by learning styles.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.37-42
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• 2015

Although online search engine service provide a convenient means to search for information on the World Wide Web, it also poses a risk of disclosing privacy. Regardless of such risk, most of users are neither aware of their personal information being exposed on search results nor how to redress the issue by requesting removal of information. According to the 2015 parliamentary inspection of government offices, many government agencies were criticized for mishandling of personal information and its leakage on online search engine such as Google. Considering the fact that the personal information leakage via online search engine has drawn the attention at the government level, the online search engine and privacy issue needs to be rectified. This paper, by examining current online search engines, studies the degree of personal information exposure on online search results and its underlying issues. Lastly, based on research result, the paper provides a sound policy and direction to the removal of exposed personal information with respect to search engine service provider and user respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.6
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• pp.435-440
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• 2014

Contact-guided-wave tests are impractical for investigating specimens with limited accessibility and rough surfaces or complex geometric features. A non-contact setup with a laser-ultrasonic transmitter and receiver is quite attractive for guided-wave inspection. In the present work, we developed a non-contact guided-wave tomography technique using the laser-ultrasonic technique in a plate. A method for Lamb-wave generation and detection in an aluminum plate with a pulsed laser-ultrasonic transmitter and Michelson-interferometer receiver was developed. The defect shape and area in the images obtained using laser scanning, showed good agreement with the actual defect. The proposed approach can be used as a non-contact online inspection and monitoring technique.