• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.435-447
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• 2019

In order to prevent unnecessary re-admission, it is necessary to intensively manage the groups with high probability of re-admission. For this, it is necessary to develop a re-admission prediction model. Two - year discharge summary data of one university hospital were collected from 2016 to 2017 to develop a predictive model of re-admission. In this case, the re-admitted patients were defined as those who were discharged more than once during the study period. We conducted descriptive statistics and crosstab analysis to identify the characteristics of rehospitalized patients. The re-admission prediction model was developed using logistic regression, neural network, and decision tree. AUC (Area Under Curve) was used for model evaluation. The logistic regression model was selected as the final re-admission predictive model because the AUC was the best at 0.81. The main variables affecting the selected rehospitalization in the logistic regression model were Residental regions, Age, CCS, Charlson Index Score, Discharge Dept., Via ER, LOS, Operation, Sex, Total payment, and Insurance. The model developed in this study was limited to generalization because it was two years data of one hospital. It is necessary to develop a model that can collect and generalize long-term data from various hospitals in the future. Furthermore, it is necessary to develop a model that can predict the re-admission that was not planned.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.145-154
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• 2019

As the interest in the positive quality of life is increasing throughout the world, the number of people who are suffering from negative sentiments, such as depression, anxiety, or stress, is increasing, as well. Especially, the adolescence period is the period of transition from childhood to adulthood and accompanies significant changes in terms of the body and mind alike. The purpose of this study is to examine the negative sentiment of the juveniles, caused by the stress they experience in their social and personal domains and the distress tolerance that can protect the inner feelings of them at the same time, to understand how they are related to the subjective well-being of the juveniles. For this study, the researcher employed the data from 362 high school students from the high schools located in Seoul and Gyeonggi area, which were analyzed using the statistics suites SPSS 22.0 and AMOS 22.0. According to the findings of this study, first, the depression and anxiety of the adolescent population showed a significant relationship for each variable with regard to the distress tolerance and the subjective well-being. Especially, the negative correlation with the subjective well-being was highly significant. Second, the depression and anxiety of the juveniles turned out to influence the distress tolerance and subjective well-being of them in a negative manner. In both distress tolerance and subjective well-being, the influence of anxiety was higher than that of depression. Third, in the relationship between depression, anxiety, and subjective well-being, the distress tolerance turned out to have a mediating effect. Such results of this study provided the basic data for suggesting the strategies to promote the perceived psychological well-being and help the juveniles who are under stress.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.187-192
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• 2019

Hybrid power storage system with emergency power function for demand management and power outage minimizes the investment cost in the building of buildings and factories requiring emergency power generation facilities, We propose a new business model by developing technology that can secure economical efficiency by reducing power cost at all times. Normally, system power is supplied to load through STS (Static Transfer Switch), and PCS is connected to system in parallel to perform demand management. In order to efficiently operate the electric power through demand forecasting, the EMS issues a charge / discharge command to the ESS as a PMS (Power Management System), and the PMS transmits the command to the PCS controller to operate the system. During the power outage, the STS is rapidly disengaged from the system, and the PCS becomes an independent power supply and can supply constant voltage / constant frequency power to the load side. Therefore, it is possible to secure reliability through verification of actual system linkage and independent operation performance of hybrid ESS, By enabling low-carbon green growth technology to operate in conjunction with an efficient grid, it is possible to improve irregular power quality and contribute to peak load by generating renewable energy through ESS linkage. In addition, the ESS is replacing the frequency follow-up reserve, which is currently under the charge of coal-fired power generation, and thus it is anticipated that the operation cost of the LNG generator with high fuel cost can be reduced.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.22-27
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• 2021

This paper is a purpose to study the failure examples for LPG vehicle. The first example, the researcher certified the incongruity phenomenon decreased engine power by ignition fire leakage because of spark plug threaded part damage assembling in cylinder head. The second example, the timing mark that accurately adjusting the camshaft and crankshaft position were twisted about 0.5 block each other. Finally, the researcher seeked the disharmony phenomenon as it couldn't set ignition timing. The third example, the researcher knew the failure phenomenon by interrupted the closing period for intake valve moving with air flow in the number 3 port of cylinder head as the foreign substance in cylinder head didn't remove. Therefore, the manager of a car has to thorough going inspect and the manufacture of a car must remove the cause of failure with quality assurance.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.71-78
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• 2021

Since most functions of modern aircraft are controlled by software, software errors are directly related to aircraft safety. The criterion in Chapter 15 of the MIL-HDBK-516C addresses safe development and verification of military aircraft software. As the U.S. Air Force repeatedly experienced non-compliance with Chapter 15 criterion of the MIL-HDBK-516C, it published an Airworthiness Circular (AC-17-01) as a guide to meeting the criterion. In this paper, Chapter 15 of MIL-HDBK-516C, AC-17-01 and the SW Qualification Guideline (DO-178C) as applied by the Federal Aviation Administration are compared and analyzed. For the analysis, a matching ratio formula between the MIL-HDBK-516C criteria specified in AC-17-01 and the DO-178C specified in MIL-HDBK-516C criteria is defined. The sections that satisfy MIL-HDBK-516C criterion are derived when AC-17-01 or DO-178C matches. Based on the analysis results, the aircraft software development process is established and examples of application of Chapter 15 of MIL-HDBK-516C are addressed.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.8
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• pp.117-128
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• 2018

The central of Ulsan was formed and has been developed in alluvial plains the Riverfront of Taehwa River and Dongcheon River Fortresses including Gyebyeonseong of the late Silla, Chisoseong of the Goryeo, Ulsan Gyeonsangjwabyeongyeongseong, Ulsaneupseong, Ulsanwaeseong and Yeompoyeongseong as well as Gugangseowon and Old Ulsanhyanggyo and other facilities well display such fact. In the southern areas of Taehwa River, Byeokpajeong of Samsan, Buddhist temples and pavilion architectures used to be located. In its upstream areas, Eonyangeupseong, Eonyanghyanggo, Banguseowon and Daegokcheon Petroglyph exist as well. As such, the Riverfront of Taehwa River are a central space where the civilization of Ulsan has grown and developed, and are regarded as a core scenic asset of Ulsan. However, the look and nature of Taehwa River changed significantly due to Ulsan irrigation project and the construction of modern bridges such as Ulsangyo and Ulsan railway bridge during the period of Japanese occupation. The old look of the area started to be ruined by water contaminations and developments of waterfront lands that resulted from the development of Ulsan Industrial Center in 1962. The water quality of Taehwa River has been improved as a result of allotting a huge budget and administrative powers before and after 1997, the year when Ulsan was elevated to a metropolitan city. However, the surrounding views around Taehwa River changed greatly due to various urban development projects including apartment complex constructions. This is because the development of the Riverfront started from a land utilization project, in which the construction of apartment complexes was included in the initial phase; as a result, the areas were changed to be private scenic assets for those apartments. Aware of such issue, this study aims to identify major scenic elements that were present in the period before such developments in the river's surrounding areas from literature and geography materials; and to reveal how various urban development projects that have been performed from the period of Japanese occupation have changed the scenic elements of Riverfront of Taehwa River. The purpose of this study is to identify qualitative and quantitative changes in scenic elements of the Riverfront of Taehwa River as well as the characteristics of the resulting changes in the surrounding scenery.

• Journal of agricultural medicine and community health
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• v.45 no.4
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• pp.183-193
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• 2020

Objectives: As an ecological study, this study was performed to identify the community-level variation of health related quality-of-life (HRQOL), and to explore the factors that explain the variation, using 2017 Korean Community Health Survey (KCHS) data. Methods: Community health indicators of KCHS, which are correlated with the EQ-5D index of Si-gun-gu districts, were selected as independent variables. Multiple linear regression model was used to derive factors that explain regional variations in the EQ-5D index. Results: The EQ-5D index variation in 229 districts nationwide was 1.1 times for extremal quotient (EQ) and 1.0 for coefficient of variance (CV). The Si-gun-gu districts with the EQ-5D index in the lower 25% were more distributed in the province (27.7%) than in the metropolitan area (20.3%). As a result of multiple linear regression analysis, the depressed mood experience rate, perceived stress rate, suicide ideation rate, and physician diagnosed arthritis rate were derived as major factors of the variation. Conclusions: In order to reduce the gap in HRQOL between the districts, the priority of local health policies should be placed on the above factors including psychosocial factors.

• Journal of Korean Medicine for Obesity Research
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• v.20 no.2
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• pp.178-192
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• 2020

Objectives: The present study aimed to compare the impacts of cognitive behavioral therapy (CBT) and behavioral treatment (BT) on weight loss and psychological outcomes among patients with three different subtypes of obesity: simple obesity, obesity with binge eating disorder, and obesity with depression. Methods: Embase, PubMed, the Cochrane Central Register of Controlled Trials, Research Information Sharing Service, and Korean Studies Information Service System were systematically searched for randomized controlled trials conducted on or before May 2020, that used CBT to treat obesity. Methodological quality was assessed using Cochrane's risk of bias tool 2 and publication bias was evaluated through the funnel plot using the trim and fill method, Egger's test, and Begg and Mazumdar rank correlation test. A meta-analysis was conducted using a random-effects model and the standardized mean difference with 95% confidence interval (CI) was used to determine effect size. Results: Twenty-one randomized controlled trials with a total of 22 intervention arms and 2,590 patients were included. Our study results revealed that the effects of CBT, compared with BT, on weight loss distinctly differed across all patient subgroups. In the simple obesity group, CBT was more effective than BT (Hedges' g=0.138, CI=0.012~0.264); however, in the obesity with binge eating disorder group, BT was more effective than CBT (Hedges' g=-0.228, CI=-0.418~-0.038); in the obesity with depression group, the effect of CBT was not statistically different from that of BT (Hedges' g=0.276, CI=-0.307~0.859). Further studies with larger sample sizes are required to confirm the outcomes observed in this study. Conclusions: Our results indicated that the effects of CBT on obesity treatment vary based on patient subtype. Therefore, our findings suggest that CBT or BT should be selectively recommended as a treatment strategy for different obesity subtypes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.1-10
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• 2021

The interest in underwater acoustic sensor networks (UWASNs), along with the rapid development of underwater industries, has increased. To operate UWASNs efficiently, it is important to adopt well-designed medium access control (MAC) protocols that prevent collisions and allow the sharing of resources between nodes efficiently. On the other hand, underwater channels suffer from a narrow bandwidth, long propagation delay, and low data rate, so existing terrestrial node pairing schemes for non orthogonal multiple access (NOMA) cannot be applied directly to underwater environments. Therefore, a multi-dimensional node pairing scheme is proposed to consider the unique underwater channel in UWASNs. Conventional NOMA schemes have considered the channel quality only in node pairing. Unlike previous schemes, the proposed scheme considers the channel gain and many other features, such as node fairness, traffic load, and the age of data packets to find the best node-pair. In addition, the sender employs a list of candidates for node-pairs rather than path loss to reduce the computational complexity. The simulation results showed that the proposed scheme outperforms the conventional scheme by considering the fairness factor with 23.8% increases in throughput, 28% decreases in latency, and 5.7% improvements in fairness at best.