• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.174-174
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• 2022

수질지수는 여러 수질 데이터 값을 수학적으로 결합하고 다 변수 특성을 줄여 수치 및 등급으로 나타낸 지표이다. 수질지수를 통해 수질을 평가하고 서로 다른 위치와 시간의 수역을 종합적으로 비교할 수 있으며 수자원관리에 있어 정책입안자, 의사결정자, 국민이 수질에 대해 일반적이고 쉽게 이해할 수 있다. 현재 환경부에서는 국내수질자동측정망 최근 12시간 데이터 값을 근거로 실시간수질지수 RTWQI(Real-Time Water Quality)값을 제공한다. 국내 호소에 설치된 수질 자동측정망은 총 8개소이며 매 시간 공통 항목인 수온, pH, DO, 전기전도도, TOC 5개, 선택항목인 탁도, Chl-a, TN, TP, 중금속, 생물감시항목 등 27개를 측정한다. RTWQI는 캐나다에서 2001년에 개발된 CCME WQI(Canadian Council of Ministers of the Environment Water Quality Index) 산출식을 기초하였으며 F1(기준치를 위반하는 수질항목의 개수/ 총 수질항목 개수), F2(기준치를 위반한 샘플들의 총 횟수/총 샘플횟수) F3(기준치를 위반한 정도) 3가지의 요소로 계산된다. 그러나RTWQI 산출식의 기초인 CCME WQI는 개발 이후 여러 문제점들은 개선되었으나 F1이 다른 F2, F3 보다 CCME WQI 점수의 기여도가 2배 이상 높은 문제점은 개선하지 못하였다. 본 연구에서는 수질자동측정망이 설치된 2012년 7월부터 2021년 12월 동안 매 시간 별 수질 데이터를 이용하였다. 또한 CCME WQI 문제점을 개선한 MWQI(Modification of Canadian water qaulity index)를 기초하여 실시간 수질지수를 재 산정하였다. 추가적으로 Pearson 상관관계 분석 및 추가 통계분석을 통해 환경부에서 제공하는 기존의 RTWQI, 개선된 실시간수질지수, 한국형 호소수질평가지수 LQI(Lake Water Quality Index)를 비교 및 평가하였다. 이러한 연구를 통해 정확성 높은 수질지수를 찾고 수자원 관리 정책 수립에 적극 활용 될 수 있을 것으로 사료된다.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.617-628
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• 2023

This study aimed to evaluate the engine load factor (LF) of a 90 kW agricultural combine harvester. The combine harvester used in this study is equipped with an electronic engine, and real-time engine data (torque and speed) was collected through a controller area network. The speed of the combine harvester during harvesting operation was divided into three levels (4, 5, and 6 km/h) for the representative operation speed range of 4 to 6 km/h. The LF was calculated using the engine load data measured in real time during harvesting. A weight was applied to the LF for each condition based on a survey of the usage. Results of the field test showed that the LF was 0.53, 0.64, and 0.87 at working speeds of 4, 5, and 6 km/h, respectively. The highest engine load factor was recorded at 6 km/h. Finally, based on the weight for the usage applied, the integrated engine LF was analyzed to be 0.69, which is approximately 144% higher than the currently applied LF of 0.48. A study on LF analysis for the entire work cycle, including idling and driving of the combine harvester, will be addressed in a future study.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.563-570
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• 2024

This paper proposes a method to recognize and track drivable lane areas to assist the driver. The main topic is designing a deep-based network that predicts drivable road areas using computer vision and deep learning technology based on images acquired in real time through a camera installed in the center of the windshield inside the vehicle. This study aims to develop a new model trained with data directly obtained from cameras using the YOLO algorithm. It is expected to play a role in assisting the driver's driving by visualizing the exact location of the vehicle on the actual road consistent with the actual image and displaying and tracking the drivable lane area. As a result of the experiment, it was possible to track the drivable road area in most cases, but in bad weather such as heavy rain at night, there were cases where lanes were not accurately recognized, so improvement in model performance is needed to solve this problem.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.347-361
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• 2023

Water utilities are making various efforts to reduce water losses from water networks, and an essential part of them is to recognize the moment when a pipe burst occurs during operation quickly. Several physics-based methods and data-driven analysis are applied using real-time flow and pressure data measured through a SCADA system or smart meters, and methodologies based on machining learning are currently widely studied. Water utilities should apply various approaches together to increase pipe burst detection. The most intuitive and explainable water balance method and its procedure were presented in this study, and the applicability and detection performance were evaluated by applying this approach to water supply pipelines. Based on these results, water utilities can establish a mass balance-based pipe burst detection system, give a guideline for installing new flow meters, and set the detection parameters with expected performance. The performance of the water balance analysis method is affected by the water network operation conditions, the characteristics of the installed flow meter, and event data, so there is a limit to the general use of the results in all sites. Therefore, water utilities should accumulate experience by applying the water balance method in more fields.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.430-441
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• 2006

As the various A/V devices and home networks are delivered to users, home networks are changing to an entertainment network. It is expected that the required network bandwidth and the amount of usage of media content in home entertainment networks will be increased. Although the access networks and home networks becoming a high speed network, there remains the problems for QoS-guaranteed media content transfer in home networks. Also, in the home network, there can be network traffic caused by applications like video conferencing, video telephone, and VoIP(voice over IP) as well as inner network traffic of home network. Since media content transfer requires the real-time delivery, it is very important and basic requirement that is to transfer media content to A/V device user wants while keeping the media quality. Even though there are many middleware protocol for home networking, they provide basic device discovery and control or simple functions for QoS-guaranteed media content transfer that are not enough to provide QoS-guaranteed media transfer service that user wants. Thus, in this paper, we propose the technique based on UPnP(universal plug and play) protocol for QoS-guaranteed media content transfer in the home network. The proposed technique is compatible with UPnP and can be used with UPnP as additional functions. In this paper, we utilize VideoLAN application to verify the proposed technique. We add the additional modules that support the proposed technique's function to VideoLAN and we verify the its functions through various test scenarios.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.161-172
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• 2005

This study is to develop Bus Transit Route Analysis and Evaluation Model that can product the quantitative performance measures for Bus Transit Route Network Design. So far, in Korea, there are no so many models that evaluate a variety of other performance measures or service quality that are of concern to both the transit users and operator because of lower-level bus database system and transit route network analysis algorithm's limit. The BTRAEM in this research differ from the previous approach in that the BTRAEM employs a multiple path transit trip assignment model that explicitly considers the transfer and different travel time after boarding. And we develop input-output data structure and quantitative performance measure for the BTRAEM. In the numerical experimental applying BTRAEM to Mandl transit network, We got the meaningful results on performance measure of bus transit route network. In the future, we expect BTRAEM to give a good solution in real transit network.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.45-55
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• 2021

This paper has proposed an algorithm that detecting for dense small vehicle in large image efficiently. It is consisted of two Ensemble Deep-Learning Network algorithms based on Coarse to Fine method. The system can detect vehicle exactly on selected sub image. In the Coarse step, it can make Voting Space using the result of various Deep-Learning Network individually. To select sub-region, it makes Voting Map by to combine each Voting Space. In the Fine step, the sub-region selected in the Coarse step is transferred to final Deep-Learning Network. The sub-region can be defined by using dynamic windows. In this paper, pre-defined mapping table has used to define dynamic windows for perspective road image. Identity judgment of vehicle moving on each sub-region is determined by closest center point of bottom of the detected vehicle's box information. And it is tracked by vehicle's box information on the continuous images. The proposed algorithm has evaluated for performance of detection and cost in real time using day and night images captured by CCTV on the road.

• Journal of Environmental Impact Assessment
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• v.30 no.2
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• pp.75-88
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• 2021

Six locations in the automated monitoring network at the Geum River Basin were selected forthis study. The water quality characteristics at two of the locations in the water quality monitoring network that were identical, or nearby, were examined, and their correlations were evaluated through statistical analysis. The results of the water quality analysis were converted to the water quality index and expressed in grades for comparison. For the data necessary for the study, public data from four years, from 2016-2019 were used and the evaluation parameters were water temperature, pH, EC, DO, TOC, TN, and TP. Results of the analysis showed that the water quality concentrations measured in the automated monitoring network and the water quality monitoring network differed in some measured values, but they tended to register variation in a specified ratio in most of the locations in the network. The analysis of the correlations of the parameters between the two monitoring networks found that water temperature, EC, and DO showed high correlations between the two monitoring networks. The TOC, TN, and TP showed high correlations, with a 0.7 or higher (correlation coefficient r), with the exception of some of the monitoring networks, although their correlations were lower than those of the basic parameters. The water quality index analysis showed that the water quality index values of the automated monitoring network and the water quality monitoring network were similar. The water quality index decreased and the pollution degree increased in the downstream direction, in both networks.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.125-139
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• 2021

Continuous subway line expansion over the years in Seoul metropolitan area has contributed to improved accessibility to public transport. Since public transport accessibility has a significant impact on housing decisions, quantitative analysis of correlation between housing prices and public transport accessibility is regarded as one of the most important factors for planning better housing policies. This study defines the reduction of traveling time resulted from the construction of new metro stations despite them not being the closest stations as 'Network Expansion Effect', and seeks to understand how the Network Expansion Effect impacts on housing prices. The study analyzes monthly rent data converted from upfront lump sum deposit, so called Jeonse in Korea, from 2012 to 2018, through 'A Modified Repeat Sales Model.' As a result, the effect of 'Network Expansion' on rental prices in Seoul has stronger during the period of 2017 to 2018 than the base period of 2012 to 2014, which suggests the 'Network Expansion' has a meaningful effect on rent. In addition, in comparison between the most and the least affected group of apartments by 'Network Expansion Effect', the most affected group has more price increase than the least affected group. These findings also indicate that different levels of 'Network Expansion Effect' have various influences on the value of residential real estate properties.

• Journal of IKEEE
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• v.15 no.1
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• pp.104-112
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• 2011

During the ground operation of Korean army, the voice message is mainly used for exchanging informations related to the surveillance and reconnaissance, command and control, and precision strike. However, in order to the battlefield visualization among fighting powers participating in the ground force operation, automatic situational awareness and variable message format (VMF) for command and control are required. For securing core technologies necessary for the battlefield visualization, message standard and message handler are established through several applied researches. Besides, the VMF for equipping a weapon system is in development. In this paper, a study on the Korean variable message format (KVMF), where interoperability of integrated battle management system (BMS) is guaranteed due to performing joint, ground, and combined operations so that the situation awareness and strike system can be automated in almost real time, is presented. From the modeling and simulation (M&S) results of the message processor, delay time is varied in accordance with the number of nodes in unit platoon network, message length, and generation interval of routine messages. Therefore, it is shown that the system performance can be optimized by establishing proper network protocol for each situation.