• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.148-159
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• 2018

Purpose: Unmanned air vehicle (UAV) remote sensing was applied to test various vegetation indices and make prediction models of protein content of rice for monitoring grain quality and proper management practice. Methods: Image acquisition was carried out by using NIR (Green, Red, NIR), RGB and RE (Blue, Green, Red-edge) camera mounted on UAV. Sampling was done synchronously at the geo-referenced points and GPS locations were recorded. Paddy samples were air-dried to 15% moisture content, and then dehulled and milled to 92% milling yield and measured the protein content by near-infrared spectroscopy. Results: Artificial neural network showed the better performance with $R^2$ (coefficient of determination) of 0.740, NSE (Nash-Sutcliffe model efficiency coefficient) of 0.733 and RMSE (root mean square error) of 0.187% considering all 54 samples than the models developed by PR (polynomial regression), SLR (simple linear regression), and PLSR (partial least square regression). PLSR calibration models showed almost similar result with PR as 0.663 ($R^2$) and 0.169% (RMSE) for cloud-free samples and 0.491 ($R^2$) and 0.217% (RMSE) for cloud-shadowed samples. However, the validation models performed poorly. This study revealed that there is a highly significant correlation between NDVI (normalized difference vegetation index) and protein content in rice. For the cloud-free samples, the SLR models showed $R^2=0.553$ and RMSE = 0.210%, and for cloud-shadowed samples showed 0.479 as $R^2$ and 0.225% as RMSE respectively. Conclusion: There is a significant correlation between spectral bands and grain protein content. Artificial neural networks have the strong advantages to fit the nonlinear problem when a sigmoid activation function is used in the hidden layer. Quantitatively, the neural network model obtained a higher precision result with a mean absolute relative error (MARE) of 2.18% and root mean square error (RMSE) of 0.187%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.1-10
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• 2012

Mobility and quality of service (QoS) are becoming the more important issues in wireless communications. The traditional Internet service is expanding into new access media and applications. Since wireless communication services are accompanied by frequent handovers at remote sites, scalable and fast handover has become a prerequisite for ubiquitous communication. In this paper, the differentiated service (Diffserv) model is deployed in heterogeneous proxy mobile IPv6 (PMIPv6) networks to satisfy the QoS guaranteed service and fast handover requirements. The operational procedures for QoS guaranteed global roaming are presented. In addition, QoS management and handover cost evaluation schemes based on a mobile host's movement scope are proposed. This paper analyzes the reduction in handover delay in a network-based localized mobility management framework. We propose and analyze a PMIPv6 optimized with a global mobile access gateway (G-MAG), which is a network-based entity, to further improve the handover performance in terms of handover delay while maintaining minimal signaling overhead in the air interface among converged heterogeneous wireless networks. The handover signaling procedures with host-based MIPv6 are compared with network-based proxy MIPv6 (PMIPv6) and fast PMIPv6 assisted by G-MAG to show how much handover delay reduction can be achieved. Analytical results show that the handover delay is significantly reduced.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.164-172
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• 2015

Seoul subway plays an important part for the public transportation service in Seoul metropolitan area. As the subway system is typically a closed environment, frequent air pollution problems occurred and passengers get malhealth impact. Especially particulate matters (PM) is well known as one of the major pollutants in subway environments. The purpose of this study was to compare the concentrations of $PM_{10}$ and $PM_{2.5}$ in the Seoul subway system and to provide fundamental data in order to management of subway system. $PM_{10}$ and $PM_{2.5}$ samples were collected in the M station platform and tunnel of Subway Line 4 in Seoul metropolitan and in an outdoor location close to it from Apr. 21, 2010~Oct. 27, 2013. The samples collected on teflon filters using $PM_{10}$ and $PM_{2.5}$ mini-volume portable samplers and PM sequential sampler. The PM contributions were $48.6{\mu}g/m^3$ (outdoor), $84.6{\mu}g/m^3$ (platform) and $204.8{\mu}g/m^3$ (tunnel) for $PM_{10}$, and $34.6{\mu}g/m^3$ (outdoor), $49.7{\mu}g/m^3$ (platform) and $83.1{\mu}g/m^3$ (tunnel) for $PM_{2.5}$. The $PM_{10}$ levels inside stations and outdoors are poorly correlated, indicating that $PM_{10}$ levels in the metro system are mainly influenced by internal sources. In this study, we compared PM concentrations before and after operation of ventilation and Electrostatic Precipitator (EP). Despite the increased PM concentration at outdoor, $PM_{10}$ concentration at platform and tunnel showed the 31.2% and 32.3% reduction efficiency after operation the reduction system. The overall results of this study suggest that the installation and operation of the ventilating system and EP should have served as one of the important components for maintaining the air quality in the subway system.

• The Journal of the Korea Contents Association
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• v.20 no.11
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• pp.170-183
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• 2020

This study sought to investigate the relationship between emotional labor and commitment to organization of flight attendants as a way to identify solutions for service quality issues attributed to reduced commitment. It was also intended to determine the relational routes in terms of the effects of social support as a supplementary factor in reduced air service quality. A survey was conducted from January 2020 for about one month and a total of 426 copies were used in the final analysis. SPSS 23.0 and AMOS 23.0 statistical programs were used for the data analysis. The results are as follows. First, the emotional labor of flight attendants showed a negative impact on the social support including support from peers, families, and team leaders. Second, support from peers and team leaders had a positive impact on commitment to organization. Third, the emotional labor of flight attendants showed a negative impact on their commitment to organization. Fourth, support from peers and team leaders were found to have a mediated effect on the relationship between emotional labor and commitment to organization.

• Korean journal of food and cookery science
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• v.27 no.4
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• pp.35-46
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• 2011

We developed hasuo jeungpyun with added polygonum multiflorum Thunb powder to increase the functional value and flavor of traditional jeungpyun. Hasuo jeungpyun containing 0, 2, 4, 6 and 8% polygonum multiflorum Thunb powder was prepared and the moisture contents, pH, color, texture and sensory analysis of the samples were measured. With increasing polygonum multiflorum Thunb powder content, the moisture content of hasuo jeungpyun decreased, and pH increased significantly. Hasuo jeungpyun prepared with 2-4% polygonum multiflorum Thunb powder displayed significantly higher swelling power. As the level of polygonum multiflorum Thunb powder increased, the L-value decreased, whereas the a- and, b-values increased. A textural profile analysis showed that the hardness increased but cohesiveness decreased with increasing polygonum multiflorum Thunb powder content. A sensory evaluation showed the highest value for air cell uniformity, flavor, and overall acceptability of 4% hasuo jeungpyun, which suggests hasuo jeungpyun with improved sensory characteristics. In the analysis of the correlation between sensory characteristics and mechanical properties of hasuo jeungpyun, hardness and brittleness were negatively correlated with after swallow, appearance, flavor, texture, taste, and overall acceptability.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.87-95
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• 2020

The Incheon airport is a gateway to and from the Republic of Korea and has a great influence on the image of the country. Therefore, it is necessary to predict the number of airport passengers in the long term in order to maintain the quality of service at the airport. In this study, we compared the predictive performance of various time series models to predict the air passenger demand at Incheon Airport. From 2002 to 2019, passenger data include trend and seasonality. We considered the naive method, decomposition method, exponential smoothing method, SARIMA, PROPHET. In order to compare the capacity and number of passengers at Incheon Airport in the future, the short-term, mid-term, and long-term was forecasted by time series models. For the short-term forecast, the exponential smoothing model, which weighted the recent data, was excellent, and the number of annual users in 2020 will be about 73.5 million. For the medium-term forecast, the SARIMA model considering stationarity was excellent, and the annual number of air passengers in 2022 will be around 79.8 million. The PROPHET model was excellent for long-term prediction and the annual number of passengers is expected to be about 99.0 million in 2024.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.81-88
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• 2011

In this study, we investigated effect of washing with brine on quality characteristics of strawberries during storage at 4 or $20^{\circ}C$. The strawberry samples were prepared with brine-washing (BW), brine-washing and removing moisture on surface (BWR), or without brine-washing and removing moisture (control). The samples were tested for total aerobic bacteria, pH, color, firmness. BWR affected the microbial change, resulting in retarding the growth of total aerobic bacteria, compared with the control and BW. The initial microbial and exponential growth phase of BWR at $4^{\circ}C$ was not detected. For pH, there wasn't dramatical change on BWR at $4^{\circ}C$ and $20^{\circ}C$. In addition, there was dramatically in decreased on control and BW. A-value was increased over storage time on control and BWR except BW. For firmness, there wasn't dramatical change on all sample when stored at $4^{\circ}C$. The results suggest that storage of strawberry stored after washing and moisture removal from the surface should be applied to maintain quality and shelf-life during storage of strawberries.

• Journal of the Economic Geographical Society of Korea
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• v.14 no.1
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• pp.19-32
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• 2011

This study compares the results of two Importance-Performance Analyses (IPA) on the convention destination images in Korea by meeting and exhibition planners. Meeting and convention planners carefully evaluate convention destinations by considering meeting room facilities, hotel service quality, safety/security, air transportation access and hotel room availability as the most important attributes of a convention destination. On the other hand, night life, exhibition facilities, scenery/sightseeing opportunities, food and lodging costs and restaurant facilities are considered as the least important attributes of a convention destination. The study revealed that convention destination attributes ranking is dynamic and continuous evaluation should be done to determine the current perception of the meeting and exhibition planners. Meeting and exhibition planners' importance grid of the convention attributes is dynamic and changed with the environment and needs of their clientele. In this study it was noted that the ranking for some attributes has dramatically changed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1140-1147
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• 2013

In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) Cargo Terminal. We measured one frequency among VHF channel bands. The transmitting site was located at different locations with different heights. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponent at IIA Cargo terminal area were 3.67 and 3.39 respectively in first and second transmitting sites. The deviation of prediction error is 14.42 and 10.38. The new path loss equation at the IIA Cargo terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.817-822
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• 2014

Since the opening of the double-track railway for the Gyeongchun local electric train and the semi-high speed train ITX, floating population between Seoul and Chuncheon has rapidly increased. This is attributable to the competitiveness of the railway service in terms of punctuality and safety of operation, mass transportation and low fare. However, many passengers have expressed strong dissatisfaction and displeasure towards the interior noise and its high rate of increase, particularly in tunnel sections. In this study, the interior noise characteristics of Gyeongchun local electric train and ITX were analyzed and compared. Noise levels, frequency spectrum and sound quality indices were compared for the open land, tunnel and bridge. Finally, from the noise levels depending on the location in the vehicle compartment, the noise transmission path was determined and a basic strategy for reducing the interior noise was developed.