• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.450-457
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• 2018

Purpose: The evaluation of seismic performance of critical structures has been emerging a key issue in Korea, since a magnitude 5.8 earthquake, the worst in Koran history, struck Gyeongju, southern area in Korea on september 12th, 2016. In particular, the catastrophic failure of nonstructural components such as sprinkler piping systems can cause significant economic loss or loss of life during and after an earthquake. The nonstructural components can be more fragile than structural components in seismic behavior. Method: This study presents the seismic performance evaluation of fire protection piping system, using coupled building-piping system installed with Triple Friction Pendulum Bearings (TPBs). Kobe (Japan), Kocaeli (Turkey), and GyeongJu (Korea) were selected to consider the uncertainty of ground motions in this study. Result: In the simulation results, it was observed that the reduction of maximum displacements of the piping system with the TPBs' system was significant: Kobe, Kocaeli, and Gyeongju cases were 49%, 14.4% and 21.5%, respectively. Conclusion: Therefore, using seismically isolated system in a building-piping system can be more effective to reduce the seismic risk than a normally installed building-piping systems without TPBs in strong earthquakes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.87-92
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• 2019

In this paper, we have verified a low-voltage EM(elasto-magnetic) sensing technique for tensile force management of PSC(prestressed concrete) internal tendon in order to apply the technique to actual construction sites where stable power supply is difficult. From observation of past domestic and overseas PSC structural accident cases, it was found that PS tension is very important to maintain structural stability. In this paper, we have tried to measure the tensile force from a magnetic hysteresis curve through EM sensors according to voltage value by using relation between magnetostriction and stress of ferromagnetic material based on elastic-magnetic theory. For this purpose, EM sensor of double cylindrical coil type was fabricated and tensile force test equipment for PS tendon using hydraulic tensioning device was constructed. The experiment was conducted to confirm relationship between changes of permeability and tensile force from the measurement results of the maximum / minimum voltage amount. The change of magnetic hysteresis curve with magnitude of tensile force was also measured by reducing amount of voltage step by step. As a result, the slope of estimation equation in accordance with magnitude of magnetic field decreases with the voltage reduction. But it was confirmed a similar pattern of change of magnetic permeability for the magnetic hysteresis loop. So, in this study, it is considered that it is possible to manage the tensions of PSC internal tendon using EM sensing technique in low-voltage state.

• Food Engineering Progress
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• v.21 no.4
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• pp.312-317
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• 2017

Weight loss that influences quality and farmer incomes is affected by the storage environment of agricultural products. The interior of storage should be maintained at high humidity to prevent the weight loss of products which contain a lot of moisture. The research had constantly proceeded with change in the heat exchanger surface areas, humidity systems, and weight loss forecast to maintain high humidity within storage. Relative humidity that exerts an effect weight loss of crop is influenced by storage temperature, leak state, and volume of product. When weight loss is predicted, different conditions of these factors are derived. In case of CA storage, ways of forecasting the weight loss become easier compared to cold storage due to sealed storage with external environment during storage period. In this study, apples were stored in purge-type CA storage and weight loss has been predicted by using operating characteristics and environmental conditions. As a result, humidity variation in the storage fluctuates with the operation of the unit-cooler. Furthermore, unit-cooler operation factor is influenced by outside temperature and respiration heat. Prediction value of weight loss according to temperature and humidity has been most accurately predicted. Prediction value through defrosting water measured shows unit-cooler work quality. K-value needs verification to calculate the VPD method.

• Journal of Convergence for Information Technology
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• v.11 no.5
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• pp.242-250
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• 2021

The subjects of this study were 514 people aged 65 and older who voluntarily participated in the senior welfare center in Seoul and Gyeonggi. The purpose of this study is to analyze the relationship between muscular strength, cognitive function, activities of daily living, depression variables of elderly people in a comprehensive evaluation. As for the data collection methods, were measured the upper and lower body strength, grip strength(left, right), cognitive function(mini-mental state examination, trail marking test, digit span test, stroop test), activities of daily living and depression was measured using a questionnaire. The results are as follows First, there was a statistically significant correlation between the elderly's muscular strength, cognitive function, daily living ability, and depression. Second, the statistical significance was found among all the variables as a result of the analysis of the elderly's integrated muscular strength, cognitive function, activities of daily living and depression. This study can provide basic data for successful aging and independent retirement life of the elderly by confirming the relationship between the elderly's muscular strength, cognitive function, Activities of daily living, and depression.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.191-212
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• 2020

In this study, a study on the cooperative system of the Chungnam Library's joint preservation data center and a plan for the construction of the use service was proposed based on the analysis of the current status of the preservation library of the Chungcheongnam-do public library. In order to establish a cooperative plan for the joint preservation archive and to promote the provision of services, the current state of the collection of 62 public libraries in Chungnam-do and the status of the preservation archives that are operating separately were identified. As a result of the study, it was found that all matters related to the operation of the joint preservation archive should be made through agreements or consultations between the participants, and the operation of the joint preservation archive should also be made under a systematic cooperation system between the participants. To this end, it is necessary to establish a cooperative system for the Chungnam Library Joint Preservation Archives, and to form and operate the Joint Preservation Archives Steering Committee, a consultative body (cooperation network). In addition, all matters related to the operation of the Joint Preservation Archive, such as transfer criteria, must be regulated and implemented through consultation with the Joint Preservation Archive Steering Committee.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.27-32
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• 2020

This paper compare the adaptive equalization performance according to the values of adaptive step variation speed for adapting in VS-CCA (Variable Stepsize-Compact Constellation Algorithm) based on nonlinear function function of error signal. The VS-CCA algorithm compacts the 16-QAM nonconstant modulus signal into the 4 groups of 4-QAM constant modulus signal constellation in quadature plane, then the error signal is generated using the constant modulus of transmitted signal statistics. The adaptive equalizer coefficient were updated in order to achieve the minimum cost function by varying step based on the nonlinear function of error signal. In this time, the instantaneous adaptive step is determined according to the value of step variation speed of nonlinear function and the different equalization performance were obtained according to the step variation speed value. The equalizer internal index and external index which represents the robustness of external noise were used for the performance comparison index. As a result of computer simulation, it was confirmed that the value of variation speed less than 1.0 give more superior in every performance index compared to the greater than 1.0 in steady state.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.660-671
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• 2021

This paper analyzed the research trends of juvenile gambling, which is increasing due to recent changes in the internet environment. The number of domestic studies on juvenile gambling has increased, but there are few studies that analyzed both degrees and academic papers in a more comprehensive manner than addiction to the Internet, games, and drugs related to youth. The current state of juvenile gambling can lead to secondary crimes, such as illegal loans and thefts for gambling funds beyond the level of addiction, school violence and money extortion, which have been a major shock to Korean society. Therefore, it is urgent to prepare social measures because the age of adolescents who are exposed to gambling is becoming lower. Accordingly, this study analyzed 52 dissertations, 86 academic papers, and three other research reports published in Korea from 2003 to March 2020. As a result, quantitative research, research subjects, and research topics were concentrated, and there was a limit to generalization. In addition, these results will provide rich information to future studies by confirming the academic characteristics according to the times and interdisciplinary research trends that transcend individual science areas.

• Journal of Environmental Impact Assessment
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• v.29 no.6
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• pp.441-452
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• 2020

The assessment of the river environment is widely applied as a method to establish the purpose and direction of river rehabilitation projects. This includes surveying and assessing the current state of the river environment and determining whether a previous river project was properly executed. The city of Seoul executed ecological river rehabilitation activities for the tributaries of the Han River from the 2000s following a masterplan to recover the physical shape and ecological functionality of damaged rivers. After the rehabilitation activities, the river environment had been changed substantially. In this study, physical properties, water quality properties, and ecological properties were assessed for 28 tributaries underthe control of the city of Seoul, and then those 3 properties were synthetically reassessed. From the result of the study on the physical properties, it was found that mostrivers had II-III grades. As for water quality properties, rivers had III-IV grades. The damaged rivers showed low grades of D-E based on the Aquatic Ecosystem Health evaluation. Accordingly, we concluded that all rivers of Seoul City have an unhealthy environment in terms of water quality and Aquatic Ecosystem Health, therefore it is regarded that long-term and systematic improvements are required.

• Journal of Broadcast Engineering
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• v.26 no.3
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• pp.247-257
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• 2021

This paper proposes a new technique for calibrating a multi-view RGB-D camera using a 3D (dimensional) skeleton. In order to calibrate a multi-view camera, consistent feature points are required. In addition, it is necessary to acquire accurate feature points in order to obtain a high-accuracy calibration result. We use the human skeleton as a feature point to calibrate a multi-view camera. The human skeleton can be easily obtained using state-of-the-art pose estimation algorithms. We propose an RGB-D-based calibration algorithm that uses the joint coordinates of the 3D skeleton obtained through the posture estimation algorithm as a feature point. Since the human body information captured by the multi-view camera may be incomplete, the skeleton predicted based on the image information acquired through it may be incomplete. After efficiently integrating a large number of incomplete skeletons into one skeleton, multi-view cameras can be calibrated by using the integrated skeleton to obtain a camera transformation matrix. In order to increase the accuracy of the calibration, multiple skeletons are used for optimization through temporal iterations. We demonstrate through experiments that a multi-view camera can be calibrated using a large number of incomplete skeletons.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.67-74
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• 2021

Ground Operations Command (GOC) has studied various methods using artificial intelligence (AI) in order to accomplish ground missions more effectively and to strongly respond to variable strategic situations with advancements in fourth industrial revolution technology. As the result of various literature reviews, PEST-7S-SWOT is considered the most appropriate methodology for promoting strategies and for task development. These procedures consist of three stages. Phase 1 is analysis of external environmental factors from applying PEST procedures. We analyzed external environmental factors to determine opportunities and risk factors. Phase 2 is the analysis of internal environmental factors from applying 7S strategies. We analyzed the current state of an organization to find strengths and weaknesses. Phase 3 is SWOT analysis. It is based on the opportunities and risk factors from Phase 1 and the strength and weakness factors from Phase 2. We derive promotional strategies and tasks through SWOT analysis. In this study, four strategies and 11 tasks were derived for GOC AI systems. Those are promotion of policies and systems, reinforcing organizations, building an AI base, increasing expertise and capabilities, and validating PEST-7S-SWOT methodologies.