• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.561-570
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• 2010

The purpose of this study is to develop an Android smartphone app providing analysis capabilities of remote sensing images, by using mobile browsing open sources of gvSIG, open source remote sensing software of OTB and open source DBMS of PostgreSQL. In this app, five kinds of remote sensing algorithms for filtering, segmentation, or classification are implemented, and the processed results are also stored and managed in image database to retrieve. Smartphone users can easily use their functions through graphical user interfaces of app which are internally linked to application server for image analysis processing and external DBMS. As well, a practical tiling method for smartphone environments is implemented to reduce delay time between user's requests and its processing server responses. Till now, most apps for remotely sensed image data sets are mainly concerned to image visualization, distinguished from this approach providing analysis capabilities. As the smartphone apps with remote sensing analysis functions for general users and experts are widely utilizing, remote sensing images are regarded as information resources being capable of producing actual mobile contents, not potential resources. It is expected that this study could trigger off the technological progresses and other unique attempts to develop the variety of smartphone apps for remote sensing images.

• Journal of the Korean Regional Science Association
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• v.37 no.4
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• pp.75-93
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• 2021

By defining a travel disparity based on the degree to which travelers diversify their destinations, this paper examines how socioeconomic and spatial factors affect the travel disparity among the elderly in Seoul. This paper uses the COVID-19 pandemic as a natural experiment which can bring about different behavioral responses among the older travelers. Using the smart card data, we compare the destination diversification patterns before and after the pandemic. In the early morning(4:30-9:00), the degree of destination diversification varies between the core and the periphery and this trend persists through the pandemic. In the late morning(9:00-12:00), a new trend of disparity appeared after the pandemic. Although those who hold higher socioeconomic status and live closer to the core have a larger range of choices for destinations, the difference of range did not lead to differences in diversification before the pandemic, due to the discretionary nature of the elderly's trip. In contrast, as the elderly were forced to search alternative destinations right after the outbreak of the pandemic, the range of choices became an important factor causing observable differences in destination diversification. The findings suggest that the travel disparity observed during the pandemic is due to the difference in the range of choices by socioeconomic and spatial factors.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.333-349
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• 2021

The fourth industrial revolution based on information and communication technology has increased the need for an environment where contents in new technologies can be learned for the development of lifelong vocational capabilities. To prepare for this, K University's online lifelong education center has established STEP, a smart learning platform. In this study, we conducted a study and other platform case analysis for STEP learner types, a survey of learners, and a comprehensive analysis based on these results to classify characteristics by learner types. It also intended to establish a plan to provide customized services to meet the needs of STEP learners in the future. The derived results are as follows. It is necessary to constantly manage learning content difficulty and learning motivation survey, and also needs to refine the operation of learning content in terms of learning composition. In addition, it is important to secure specialized content, to manage vulnerable learners, to actively introduce a learner support system and various educational methods.

• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.144-150
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• 2021

The purpose of this paper is to review the direction of the slicing security policy, which is a major consideration in the context of standardization in 5G communication network security, to derive security vulnerability diagnosis items, and to present about analyzing and presenting the issues of discussion for 5G communication network virtualization. As for the research method, the direction of virtualization security policy of 5G communication network of ENISA (European Union Agency for Cybersecurity), a European core security research institute, and research contents such as virtualization security policy and vulnerability analysis of 5G communication network from related journals were used for analysis. In the research result of this paper, the security structure in virtualization security of 5G communication network is arranged, and security threats and risk management factors are derived. In addition, vulnerability diagnosis items were derived for each security service in the risk management area. The contribution of this study is to summarize the security threat items in 5G communication network virtualization security that is still being discussed, to be able to gain insights of the direction of European 5G communication network cybersecurity, and to derive vulnerabilities diagnosis items to be considered for virtualization security of 5G communication network. In addition, the results of this study can be used as basic data to develop vulnerability diagnosis items for virtualization security of domestic 5G communication networks. In the future, it is necessary to study the detailed diagnosis process for the vulnerability diagnosis items of 5G communication network virtualization security.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.3
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• pp.5-16
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• 2021

In this study, the applicability of the MBR(Membrane Bio Reactor) process of oxygen dissolve was evaluated through comparison and evaluation of the efficiency of oxygen dissolve device and conventional aeration device in the explosive tank within the MBR process. The organic matter and ammonia oxidation by oxygen dissolve device were evaluated, and the efficiency of persaturation was evaluated by applying real waste water (anaerobic digester effluent treatement from food waste). SCOD and ammonia removal rates for oxygen dissolve device and conventional aeration device methods were similar. However, it was determined that the excess sludge treatment cost could be reduced as the yield of microorganisms by oxygen dissolve device is about 0.03 g MLSS-produced/g SCOD-removed lower than that of microorganisms by conventional aeration device. The removal rates of high concentrations of organic matter (4,000 mg/L) and ammonia (1,400 mg/L) in anaerobic digester effluent treatment from food waste were compared to the conventional aeration device and the oxygen dissolve device organic matter removal rate was approximately 13% higher than that of the conventional aeration device. In addition, for MLSS, the conventional aeration device was 0.3 times higher than for oxygen dissolve device. This is believed to be due to the high progress of sludge autooxidation because the dissolved oxygen is sufficiently maintained and supplied in the explosive tank for oxygen dissolve device. Therefore, it was determined that the use of oxygen dissolve device will be more economical than conventional aeration device as a way to treat wastewater containing high concentrations of organic matter.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.3
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• pp.17-25
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• 2021

This study was conducted to investigate effects of mixture with dried food waste powder (FWP) and mixed organic fertilizer (MOF) on growth of pakchoi. As compared with non-fertilizer treatment (NF) or control (MOF treatment), growth of pakchoi in FWP treatments (2,500 kg/ha, 5,000 kg/ha, 10,000 kg/ha) was inhibited by salt (NaCl) content in the FWP. In comparison with control, mixtures of MOF and FWP (FWP10, FWP20, and FWP30 treatment) were not significantly different, and their salt content correlated with pakchoi growth factors negatively (P<0.05). Applied of FWP10, (FWP10: 2,500 kg/ha, 2FWP10: 5,000 kg/ha, 3FWP10: 7,500 kg/ha, 4FWP10: 10,000 kg/ha), growth factors of FWP10, 2FWP10 and 3FWP10 treatment were not significantly different than those of chemical fertilizer treatment, and of 4FWP10 decreased. Correlation coefficient between NaCl supply by FWP10 application and growth factor was negative (P<0.01). These results indicated that FWP was used as another source of organic fertilizer, and the organic fertilizers blending with FWP inhibited a pakchoi growth by increase of salt content containing in the them or of salt supplying amount after their application.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.10
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• pp.763-774
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• 2019

A collaborative system supports collaboration among participants by providing functions such as group composition and management of data shared for collaboration. In recent years, research on collaborative services based on the blockchain technology has been done to guarantee the reliability of collaboration processes and outcomes. The diversity of the application domains in which collaborations are performed and the various characteristics of the participants in the collaboration group naturally leads to various forms of collaborative processes. In order for these processes to produce the desired outcome of the collaborative efforts, it is desirable to specify the appropriate collaborative process in advance, so that the participants can understand and agree on the process, carrying out the collaboration. In this paper, we propose a method to control flexible collaborative processes according to workflow specifications in the Ethereum-based collaborative service environment. The specification of the workflow for the designated task is stored in the Ethereum smart contract and the process of performing the task is controlled according to the stored workflow specification. For this, we introduce JSFlow which is a simple workflow specification method using JSON and an Ethereum library to utilize it.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1161-1175
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• 2018

An unexpected event could be easily followed by a large secondary accident due to the limitation in sight of drivers in road tunnels. Therefore, a series of automated incident detection systems have been under operation, which, however, appear in very low detection rates due to very low image qualities on CCTVs in tunnels. In order to overcome that limit, deep learning based tunnel incident detection system was developed, which already showed high detection rates in November of 2017. However, since the object detection process could deal with only still images, moving direction and speed of moving vehicles could not be identified. Furthermore it was hard to detect stopping and reverse the status of moving vehicles. Therefore, apart from the object detection, an object tracking method has been introduced and combined with the detection algorithm to track the moving vehicles. Also, stopping-reverse discrimination algorithm was proposed, thereby implementing into the combined incident detection processes. Each performance on detection of stopping, reverse driving and fire incident state were evaluated with showing 100% detection rate. But the detection for 'person' object appears relatively low success rate to 78.5%. Nevertheless, it is believed that the enlarged richness of image big-data could dramatically enhance the detection capacity of the automatic incident detection system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.94-101
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• 2019

Most of the existing rail structures have undergone a lot of aging since a considerable period of time has passed from completion. In particular, among existing railway bridges, many of the plate girder bridges are older bridges that have lived 40 to 60 years or more. Since the treadmill is directly connected to the girder without the ballast, the running load of the vehicle is directly transmitted to the bridge. Therefore, the shock and noise applied to the bridge are larger than those of the ballast bridge, and the dynamic shock and vibration are also relatively large. Therefore, it is very urgent to develop appropriate maintenance, repair and reinforcement technology for existing steel plate bridge. In this study, the authors introduced the characteristics of embedded rail (ERS) developed for improving the performance of the existing plate girder bridge and the techniques solving the vibration and noise problems. In order to evaluate the vibration and noise reduction performance of ERS, a non-ballast plate girder bridge with 5m length of sleepers installed and a plate girder bridge with ERS were fabricated. And, then, the vibration response generated under the same excitation condition was measured and analyzed. Also, the radiated noise analysis was performed using the vibration response data obtained from the experiment as the input data of the acoustic analysis model. As a result of experiments and analyses, it was confirmed that the plate girder bridge's vibration using ERS was reduced by 15.0~18.8dB and the average noise was reduced by 7.7dB(A) more than the non-ballast bridge.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.27-35
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• 2019

The existing middle-long span railway bridge has been mainly applied to steel box girder bridges. However, the steel box girder bridges have disadvantages in securing the space under the bridge, and the main girder is made of a thin plate box shape, resulting in a ringing noise due to the vibration. Many complaints about noise have been raised. For this reason, there is a need for the development of long railway bridges that can replace steel box girder bridges. In this paper, the characteristics of the steel composite railway bridge currently developed were introduced and a time history analysis was conducted using MIDAS Civil reflecting the speed of KTX load for 40m and 50m bridges. In addition, from the analysis results, the dynamic behavior of target bridges were verified and it was examined whether they meet the dynamic performance criteria proposed in the railway design standards. As a result, all of the bridges under review satisfied the dynamic safety criteria, however, in case of 40m of span, the vertical acceleration value was very large. In order to solve this problem, authors proposed the improvement plan and corrected the cross section to confirm that the vertical acceleration decreased.