• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.5
• /
• pp.149-161
• /
• 2022

Because the speed limit affects moving speed, it is closely related to traffic accidents as well as traffic flow. The existing speed limit calculation methods consider various engineering factors such as lanes, intersection spacing, driveways, crosswalks, 85 percentile speed, land uses, and roadway geometric characteristics etc. However, it can be said that the engineering analysis is insufficient because the traffic impact analysis considering traffic volume is not carried out. In addition, only 85 percentile speed, which is the spot speed, does not reflect the characteristics of the traffic flow on the road. In this paper, the effect of the speed limit change on the moving speed and the travel speed was analyzed in detail accordinr to the variation of intersection spacing and traffic volume. And by using the results, we proposed a speed limit calculation method that maintains the same service level as before the speed limit change, thereby increasing the speed improvement effect and reducing the difference between moving speed and travel speed. In addition, a variable speed limit operation method according to the change in traffic volume was also suggested. This method is expected to be effective in terms of safety by reducing the speed difference, which affects the severity of traffic accidents, while securing the speed improvement effect, and increasing the speed limit compliance rate of drivers by operating the speed limit that reflects the speed change due to the variation of traffic volume.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.1
• /
• pp.41-49
• /
• 2023

A convolutional neural network (CNN) is a representative algorithm for implementing artificial neural networks. CNNs have improved on the issues of rapid increase in calculation amount and low object classification rates, which are associated with a conventional multi-layered fully-connected neural network (FNN). However, because of the rapid development of IT devices, the maximum resolution of images captured by current smartphone and tablet cameras has reached 108 million pixels (MP). Specifically, a traditional CNN algorithm requires a significant cost and time to learn and process simple, high-resolution images. Therefore, this study proposes an improved CNN algorithm for implementing an object classification learning model for simple, high-resolution images. The proposed method alters the adjacency matrix value of the pooling layer's max pooling operation for the CNN algorithm to reduce the high-resolution image learning model's creation time. This study implemented a learning model capable of processing 4, 8, and 12 MP high-resolution images for each altered matrix value. The performance evaluation result showed that the creation time of the learning model implemented with the proposed algorithm decreased by 36.26% for 12 MP images. Compared to the conventional model, the proposed learning model's object recognition accuracy and loss rate were less than 1%, which is within the acceptable error range. Practical verification is necessary through future studies by implementing a learning model with more varied image types and a larger amount of image data than those used in this study.

• Journal of Korea Water Resources Association
• /
• v.56 no.9
• /
• pp.587-602
• /
• 2023

Due to climate change, population growth, and economic development, the demand for water in the urban water system (UWS) and the energy required for water use constantly increase. Therefore, beyond the traditional method of considering only the water sector, the Nexus approach, which considers synergies and trade-offs between the water and energy sectors, has begun to draw attention. In previous researches, the Nexus methodology was used to demonstrate that the UWS is an energy-intensive system, analyze the water-energy efficiency relationship surrogated by energy intensity, and identify climate (long-term climate change, drought, type), geographic characteristics (topography, flat ratio, location), system characteristics (total supply water amount, population density, pipeline length), and operational management level (water network pressure, leakage rate, water saving) effects on the UWS. Through this, it was possible to suggest the direction of policies and institutions to UWS managers. However, there was a limit to establishing and implementing specific action plans. This study built the energy intensity matrix of the UWS, quantified the impact of city conditions, external influences, and operational management levels on the UWS using the water-energy Nexus model, and introduced water-energy efficiency criteria. With this, UWS managers will be able to derive strategies and action plans for efficient operation management of the UWS and evaluate suitability and validity after implementation.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.1
• /
• pp.111-119
• /
• 2019

The purpose of study was to evaluate the economic evaluation of Chuncheon curling stadium. In oder to estimate economic evaluation, benefit/cost ratio, net present value and internal rate of return were used. Additionally, in order to investigate the socio-economic spread effect, literature review and input-output analysis were used. The results of study were as follows. First, as a result of analyzing the demand for curling stadiums in Chuncheon, it was believed that the construction of the stadium will attract athletes from the Chuncheon region as well as athletes from Seoul, Incheon, Gyeonggi Province and North Chungcheong Province. Second, economic validity analysis showed that the initial investment did not make sense, but the players' training and competitions and the advantages of the potential experience of curling events for citizens in nearby areas, including Chuncheon, make the construction and operation reasonable. Third, as a result of the review of the social and policy validity of the curling stadium, the project to build a curling stadium in Chuncheon was secured with a policy validity as a public sports facility necessary for both professional and living athletes. Finally, the analysis of socio-economic spread effect of curling stadiums had shown that it would have a positive effect on the level of satisfaction of the general public as well as the discovery of elite athletes.

• Journal of Korea Water Resources Association
• /
• v.55 no.spc1
• /
• pp.1283-1293
• /
• 2022

The purpose of this study is to predict residual chlorine in order to maintain stable residual chlorine concentration in sedimentation basin by using artificial intelligence algorithms in water treatment process employing pre-chlorination. Available water quantity and quality data are collected and analyzed statistically to apply into mathematical multiple regression and artificial intelligence models including multi-layer perceptron neural network, random forest, long short term memory (LSTM) algorithms. Water temperature, turbidity, pH, conductivity, flow rate, alkalinity and pre-chlorination dosage data are used as the input parameters to develop prediction models. As results, it is presented that the random forest algorithm shows the most moderate prediction result among four cases, which are long short term memory, multi-layer perceptron, multiple regression including random forest. Especially, it is result that the multiple regression model can not represent the residual chlorine with the input parameters which varies independently with seasonal change, numerical scale and dimension difference between quantity and quality. For this reason, random forest model is more appropriate for predict water qualities than other algorithms, which is classified into decision tree type algorithm. Also, it is expected that real time prediction by artificial intelligence models can play role of the stable operation of residual chlorine in water treatment plant including pre-chlorination process.

• Nuclear Engineering and Technology
• /
• v.27 no.6
• /
• pp.877-887
• /
• 1995

YGN 3 is the first nuclear power plant to use the Core Protection Calculator (CPC) as the core protection system and the Core Operating Limit Supervisory System (COLSS) as the core monitor-ing system in Korea. The CPC is designed to provide on-line calculations of Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) and to initiate reactor trip if the core conditions exceed the DNBR or LPD design limit. The COLSS is designed to assist the operator in implementing the Limiting Conditions for Operation (LCOs) in Technical Specifications for DNBR/Linear Heat Rate (LHR) margin, azimuthal tilt, and axial shape index and to provide alarm when the LCOs are reached. During YGN 3 initial startup testing, extensive CPC/COLSS related tests ore peformed to ver-ify the CPC/COLSS performance and to obtain optimum CPC/COLSS calibration constants at var, -ious core conditions. Most of test results met their specific acceptance criteria. In the case of missing the acceptance criteria, the test results ore analyzed, evaluated, and justified. Through the analysis and evaluation of each of the CPC/COLSS related test results, it can be concluded that the CPC/COLSS are successfully Implemented as designed at YGN 3.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.6 no.7
• /
• pp.219-228
• /
• 2016

This research aimed at investigating policy change process of after school contracting out and suggesting future alternative. Also, this research conducted a literature search for the research data related to policy and related regulations. As the result of investigation, the Ministry of Education established management plan for after school, however there have been changes in policy, e.g. contracting out was executed from 2004 to 2008 upon autonomy of unit school through school steering committee deliberation(consultation), while standardized procedure was conducted, which was suggested in 'After school operation guideline', produced in cooperation between the Ministry of Education and municipal ministry of education from 2008 to 2015, while since 2016, contract law should be applied when after school contracting out is adopted. Policy change since 2016 is based on the legal necessity that contract law should be followed as the contract size of after school contracting out has become larger along with necessity of clarity of after school contracting out. Nevertheless, there's a worry that quality of after school education could be degraded due to lowest price bidding. The government suggested an alternative to prevent excessive price competition by paying a regular rate of basic price as personnel expenses, however this research suggested a plan to enact an ordinance in regard of specialty of after school educational activities and cities and provinces as the fundamental solution plan.

• Journal of Korean Library and Information Science Society
• /
• v.54 no.2
• /
• pp.43-65
• /
• 2023

The purpose of all public libraries is to provide knowledge and information services for the intellectual and reading activities of local residents, program services that provide opportunities for cultural enjoyment and lifelong learning, and third-party spaces and facilities that contribute to the development of the community. To this end, social needs must be reflected in a timely manner with the establishment of a sound infrastructure as a prerequisite. This study analyzed the current status centered on key indicators of the public libraries in Daegu City and presented policy issues that need to be improved through a survey. The key indicators in Daegu City, compared to the national average, were not only significantly weak for the 3rd largest city but also showed considerable variation among local governments. While Daegu citizens valued public libraries in their daily lives, the dissatisfaction rate was high in the order of transportation inconvenience, lack of necessary materials and desired programs, and various regulations. Therefore, Daegu City should focus on increasing the acquisition budget, strengthening the development of new book collections, expanding the number of librarians, expanding the construction of public libraries to address service disparities among local governments, improving accessibility, and addressing factors that hinder usage. In addition, with the establishment and operation of the Daegu Library in 2024, efforts should be made to establish an operational system for public libraries, expand the scope through collaborative partnerships with other knowledge and cultural institutions, and enhance knowledge and cultural services for the Daegu citizen.

• Environmental and Resource Economics Review
• /
• v.32 no.2
• /
• pp.107-126
• /
• 2023

This study analyzes the financial efficiency of the early scappage support system using the benefit and cost analysis. To do so, we use comprehensive administrative data on the early scrappage of old diesel vehicles. The result shows that the benefit-cost ratio was greater than 1 before 2020, but it appeared to be less than 1 after 2020. This indicates that despite recent reforms to increase the subsidy of early scrappage of old diesel vehicles, the rate of the benefit of air quality improvement is not as fast as the increase in system operation cost of this system. The benefit of air quality improvement depends on how much the operating period is shortened due to early scrappage support system. The earlier this period is brought forward, the more likely it is that the benefits of early scrappage will exceed the costs. Upon examining the results of this study, it was found that when the scrappage timing is brought forward by 5 years, the B/C for 98% of the samples becomes 1, greatly securing financial efficiency. Therefore, it is important for the government to reform the system so that it can influence the decision of old diesel vehicle owners on the timing of scrappage.

• The Journal of Bigdata
• /
• v.7 no.1
• /
• pp.15-27
• /
• 2022

In the past five years, the fatality rate of single-vehicle accidents has been 4.7 times higher than that of all accidents, so it is necessary to establish a system that can detect and respond to single-vehicle accidents immediately. The IoT(Internet of Thing)-based real-time traffic accident recognition system proposed in this study is as following. By attaching an IoT sensor which detects the impact and vehicle ingress to the guardrail, when an impact occurs to the guardrail, the image of the accident site is analyzed through artificial intelligence technology and transmitted to a rescue organization to perform quick rescue operations to damage minimization. An IoT sensor module that recognizes vehicles entering the monitoring area and detects the impact of a guardrail and an AI-based object detection module based on vehicle image data learning were implemented. In addition, a monitoring and operation module that imanages sensor information and image data in integrate was also implemented. For the validation of the system, it was confirmed that the target values were all met by measuring the shock detection transmission speed, the object detection accuracy of vehicles and people, and the sensor failure detection accuracy. In the future, we plan to apply it to actual roads to verify the validity using real data and to commercialize it. This system will contribute to improving road safety.