• Title/Summary/Keyword: 다중흐름모형

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Additional Freight Train Schedule Generation Model (화물열차 증편일정 결정모형)

  • Kim, Young-Hoon;Rim, Suk-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3851-3857
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    • 2014
  • Shippers' requests of freight trains vary with time, but generating an additional schedule of freight trains is not easy due to many considerations, such as the line capacity, operation rules, and conflicts with existing trains. On the other hand, an additional freight train schedule has been continuously requested and manually processed by domestic train operation companies using empirical method, which is time consuming. This paper proposes a model to determine the additional freight train schedule that assesses the feasibility of the added freight trains, and generates as many additional schedules as possible, while minimizing the delay of the existing schedules. The problem is presented using time-space network, modeled as multi-commodity flow problem, and solved using the column generation method. Three levels of experiment were conducted to show validity of the proposed model in the computation time.

Hydraulic Experiment on Roughness Coefficient of PE pipe (폴리에틸렌관의 조도계수에 관한 수리모형실험)

  • Dongwoo Ko;Byeong Wook Lee;Jae-Seon Yoon;Hyun-Gu Song
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.288-288
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    • 2023
  • 도로, 철도 등의 횡단통로, 오폐수관로, 지하배수관 등 연약지반에서 상재하중과 부등침하에 의한 파괴 위험을 줄이기 위해 구조적인 안전성과 내구성이 개선된 다양한 관로들이 활용되고 있다. 관은 매설특성에 따라 콘크리트관, 도관, 합성수지관, 덕타일 주철관, 파형강관, 유리섬유 강화 플라스틱과 폴리에스테르수지 콘크리트관 등의 종류로 구분된다(환경부, 2017). 수리설계 시 이러한 관의 단면 규모 결정 및 흐름 특성을 파악하기 위해 관수로 유량측정에 이용되는 Manning의 경험식을 이용하고 있으며, 관로의 주요 재질에 따른 다양한 조도계수가 제시되어 있다. 새로운 재질을 이용하여 제작된 관은 수리실험을 통해 조도계수를 결정하는 것이 바람직하지만, 조도계수 실험은 대규모의 실험시설과 유량공급이 요구되기 때문에 여러 한계가 있다. PE관의 경우, 미국의 ASTM 표준에 의해 저밀도 폴리에틸렌(LDPE), 선형 저밀도 폴리에틸렌(LLDPE), 고밀도 폴리에틸렌(HDPE) 등으로 분류되는데 본 연구에서는 HDPE 재질의 서로 직경이 다른 다중벽관 PE관을 대상으로 조도계수를 결정하기 위한 현장 실규모 수리실험을 수행하였다. 본 실험에서는 식생, 수로의 불규칙성, 수로노선, 침전과 세굴, 장애물, 계절적 변화, 부유물질과 소류사는 무시되며 표면조도, 관의 크기와 형상, 수위와 유량이 조도계수에 영향을 미치는 주요 인자라고 할 수 있다. 수리실험은 실물모형(Prototype)으로 한국농어촌공사 농어촌연구원의 대형수리모형실험장에서 수행되었으며. 길이 24 m, 직경 150 mm의 PE 관은 고정식 개수로, 직경 800 mm의 관은 대형유사순환수로에 각각 설치되었다. 관로의 전면에 차폐막을 설치하여 상류부 수위를 안정시킨 상태에서 실험을 수행하였고, 차폐막으로부터 하류방향으로 약 7 m(측정기준지점), 11 m, 13 m, 15 m, 17 m 떨어진 곳에서 각각 수위와 유속을 측정하였다. 실험 결과, φ150관은 직경대비 수심이 클수록 조도계수가 감소하는 경향이 나타났고, φ800관은 직경대비 수심의 변화에 따른 조도계수의 경향이 크게 드러나지 않았다. 결론적으로 PE관의 조도계수는 수심별로 변화하는 것으로 나타났으며, 특정 수심을 지나면 조도계수가 다시 감소할 것으로 판단된다.

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Automatic Collection of Production Performance Data Based on Multi-Object Tracking Algorithms (다중 객체 추적 알고리즘을 이용한 가공품 흐름 정보 기반 생산 실적 데이터 자동 수집)

  • Lim, Hyuna;Oh, Seojeong;Son, Hyeongjun;Oh, Yosep
    • The Journal of Society for e-Business Studies
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    • v.27 no.2
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    • pp.205-218
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    • 2022
  • Recently, digital transformation in manufacturing has been accelerating. It results in that the data collection technologies from the shop-floor is becoming important. These approaches focus primarily on obtaining specific manufacturing data using various sensors and communication technologies. In order to expand the channel of field data collection, this study proposes a method to automatically collect manufacturing data based on vision-based artificial intelligence. This is to analyze real-time image information with the object detection and tracking technologies and to obtain manufacturing data. The research team collects object motion information for each frame by applying YOLO (You Only Look Once) and DeepSORT as object detection and tracking algorithms. Thereafter, the motion information is converted into two pieces of manufacturing data (production performance and time) through post-processing. A dynamically moving factory model is created to obtain training data for deep learning. In addition, operating scenarios are proposed to reproduce the shop-floor situation in the real world. The operating scenario assumes a flow-shop consisting of six facilities. As a result of collecting manufacturing data according to the operating scenarios, the accuracy was 96.3%.

Calculation of Watershed Topographic Index with Geographic Information System (지리정보시스템을 이용한 유역에서의 지형지수 산정)

  • 김상현;한건연
    • Water for future
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    • v.29 no.4
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    • pp.199-208
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    • 1996
  • The multiple flow direction algorithm to calculate the spatial variation of the saturation tendency, i.e. topographic index, is integrated into the Geogrphic Information System, GRASS. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed (3.4$\textrm{km}^2$) is used for this study. The impact of a tile system on the groundwater table can be effectively considered by the Laplace's equation to the DEM. The analysis shows that a tile system has a high degree of saturation compared to the case without tile drainage, and the predicted riparian area is well fitted to the actual watershed condition. A procedure is suggested to consider the effect of tile system on calculating the topographic index.

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Saturation Tendency for Tracing of Runoff Path on GIS Platform (유출경로 추적을 위한 GIS상에서의 유역 포화성향 고찰)

  • Kim, Sanghyun;Kunyeoun Han
    • Proceedings of the Korea Water Resources Association Conference
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    • 1997.05a
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    • pp.192-198
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    • 1997
  • The spatial variation of saturation tendency can be calculated from the Digital Elevation Model (DEM) employing the multiple flow direction algorithm on the platform of Geographic Resources Support Analysis System (GRASS). It is expected that a bettter understanding of dynamical runoff processes in hillslope hydrological scale is obtained through tracing various runoff path such as infiltration excess overland flow component, strutation excess overland flow component and subsurface runoff component. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed (3.4 km2) is used for this study.

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A Study on the Policy Decision Making Process of Seoul-Type Paid Sick Leave: Applying Kingdon's Multiple Streams Model (다중흐름모형을 적용한 서울형 유급병가 정책 도입과정에 관한 연구)

  • Jung, Hyun Woo;Park, So Hyeon;Sohn, Minsung;Chung, Haejoo
    • Health Policy and Management
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    • v.30 no.3
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    • pp.286-300
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    • 2020
  • In 2019, the Seoul metropolitan government established its own 'Seoul-type paid sick leave project'. Although the central government had to introduce such a system, which is also called sickness benefits, it was not implemented. In order to understand the process by which the Seoul government has implemented such a policy, this study used Kingdon's multiple streams framework. As a result, in the problem stream, it was found that the economic burden of sickness has been considered only in terms of medical expenses in the past of Korea. Then Songpa's three women and Middle East respiratory syndrome incidents raised awareness of the necessity of the sickness benefit system in 2014 and 2015. In the political stream, several social affairs such as national health insurance huge surpluses and the 2017 presidential election opened policy window. At that time, Seoul Mayor actively promoted sickness benefits as a policy entrepreneur. In the policy stream, the sickness benefit system has gained new attention through political events. To summary, these three streams flowed separately and then they assembled around huge political affairs. As a result, it was confirmed that Kingdon's model is the most effective theory than any other models in analyzing the health care policy decision process in Korea.

An Analysis on the Process of Policy Formation of Smart Farms Dissemination applying Multiple Streams Framework (다중흐름모형(MSF)을 적용한 스마트팜 확산 정책형성과정 분석)

  • Jeong, Yunyong;Hong, Seungjee
    • Journal of Korean Society of Rural Planning
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    • v.25 no.1
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    • pp.21-38
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    • 2019
  • Korean agricultural industry has weakened as demand for domestic agricultural products has declined due to accelerating market liberalization, aging and shrinking of rural population, and stagnating rural households' incomes. On the other hand, as the forth industrial revolution unfolds in earnest, tremendous changes are expected, and those changes won't be confined to certain industries but would shaken the world we know of entirely. Smart farm, which is one example of the fourth industrial revolution, is increasingly being recognized as a new growth engine for the future as smart farm and the science and technology behind it, not the size of arable land, will determine competitiveness of the agricultural industry and drive agricultural productivity and managerial efficiency. In consideration that John W. Kingdon's Multiple Streams Framework has recently been presented as an important theoretical model in the policy field, this study analyzed problem stream, policy stream, and political stream in the process of forming the smart farm policy, and looked into what role the government played as policy entrepreneur in policy window. The smart farm policy was put on policy agenda by the government and was approved when the government announced the Smart Farm Plan together with relevant ministries at the 5th Economy-Related Ministers' Meeting held in April 2018. This suggests that change of the government is the most critical factor in political stream, and explicitly indicates the importance of politics in formation of an agricultural policy. In addition, actual outcome of the policy and how policy alternatives that will enhance people's understanding will support it seem to be the key to success. It also shows that it is important that policy alternatives be determined based on sufficient discussion amongst stakeholders.

A Study on Distributed Collective Energy Policy Changes: Focusing on the National Heat Map Project Based on Energy Data (분산형 집단에너지 정책변동 연구: 에너지 데이터 기반의 국가 열지도 사업을 중심으로)

  • Park Eunsook;Park Yongsung
    • Knowledge Management Research
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    • v.24 no.1
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    • pp.195-221
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    • 2023
  • As the global energy and climate crisis has complicated interests of each country, the agenda that requires a global response has recently been revived. In particular, Korea is highly dependent on energy imports and continues to have high energy consumption, low efficiency of energy consumption, and high greenhouse gas emissions, so innovative and effective energy policies are urgently needed to achieve energy efficiency and carbon neutrality. In this study, among the changes in distributed district energy policy after the integrated energy method was introduced in Korea in the mid-1980's, the case of the "National Heat Map Project" policy implementation is analyzed with a modified multi-flow model. The 10 years of the Lee Myung-bak and Park Geun-hye administrations, the period of study, was a period in which the main paradigm of energy policy shifted to a "distributed energy platform" and policy transitions such as policy agenda setting, policy drift, and policy revision were made. A study on the process would be meaningful.

Corporate Default Prediction Model Using Deep Learning Time Series Algorithm, RNN and LSTM (딥러닝 시계열 알고리즘 적용한 기업부도예측모형 유용성 검증)

  • Cha, Sungjae;Kang, Jungseok
    • Journal of Intelligence and Information Systems
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    • v.24 no.4
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    • pp.1-32
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    • 2018
  • In addition to stakeholders including managers, employees, creditors, and investors of bankrupt companies, corporate defaults have a ripple effect on the local and national economy. Before the Asian financial crisis, the Korean government only analyzed SMEs and tried to improve the forecasting power of a default prediction model, rather than developing various corporate default models. As a result, even large corporations called 'chaebol enterprises' become bankrupt. Even after that, the analysis of past corporate defaults has been focused on specific variables, and when the government restructured immediately after the global financial crisis, they only focused on certain main variables such as 'debt ratio'. A multifaceted study of corporate default prediction models is essential to ensure diverse interests, to avoid situations like the 'Lehman Brothers Case' of the global financial crisis, to avoid total collapse in a single moment. The key variables used in corporate defaults vary over time. This is confirmed by Beaver (1967, 1968) and Altman's (1968) analysis that Deakins'(1972) study shows that the major factors affecting corporate failure have changed. In Grice's (2001) study, the importance of predictive variables was also found through Zmijewski's (1984) and Ohlson's (1980) models. However, the studies that have been carried out in the past use static models. Most of them do not consider the changes that occur in the course of time. Therefore, in order to construct consistent prediction models, it is necessary to compensate the time-dependent bias by means of a time series analysis algorithm reflecting dynamic change. Based on the global financial crisis, which has had a significant impact on Korea, this study is conducted using 10 years of annual corporate data from 2000 to 2009. Data are divided into training data, validation data, and test data respectively, and are divided into 7, 2, and 1 years respectively. In order to construct a consistent bankruptcy model in the flow of time change, we first train a time series deep learning algorithm model using the data before the financial crisis (2000~2006). The parameter tuning of the existing model and the deep learning time series algorithm is conducted with validation data including the financial crisis period (2007~2008). As a result, we construct a model that shows similar pattern to the results of the learning data and shows excellent prediction power. After that, each bankruptcy prediction model is restructured by integrating the learning data and validation data again (2000 ~ 2008), applying the optimal parameters as in the previous validation. Finally, each corporate default prediction model is evaluated and compared using test data (2009) based on the trained models over nine years. Then, the usefulness of the corporate default prediction model based on the deep learning time series algorithm is proved. In addition, by adding the Lasso regression analysis to the existing methods (multiple discriminant analysis, logit model) which select the variables, it is proved that the deep learning time series algorithm model based on the three bundles of variables is useful for robust corporate default prediction. The definition of bankruptcy used is the same as that of Lee (2015). Independent variables include financial information such as financial ratios used in previous studies. Multivariate discriminant analysis, logit model, and Lasso regression model are used to select the optimal variable group. The influence of the Multivariate discriminant analysis model proposed by Altman (1968), the Logit model proposed by Ohlson (1980), the non-time series machine learning algorithms, and the deep learning time series algorithms are compared. In the case of corporate data, there are limitations of 'nonlinear variables', 'multi-collinearity' of variables, and 'lack of data'. While the logit model is nonlinear, the Lasso regression model solves the multi-collinearity problem, and the deep learning time series algorithm using the variable data generation method complements the lack of data. Big Data Technology, a leading technology in the future, is moving from simple human analysis, to automated AI analysis, and finally towards future intertwined AI applications. Although the study of the corporate default prediction model using the time series algorithm is still in its early stages, deep learning algorithm is much faster than regression analysis at corporate default prediction modeling. Also, it is more effective on prediction power. Through the Fourth Industrial Revolution, the current government and other overseas governments are working hard to integrate the system in everyday life of their nation and society. Yet the field of deep learning time series research for the financial industry is still insufficient. This is an initial study on deep learning time series algorithm analysis of corporate defaults. Therefore it is hoped that it will be used as a comparative analysis data for non-specialists who start a study combining financial data and deep learning time series algorithm.

Spatial-temporal Distribution of Soil Moisture at Bumreunsa Hillslope of Sulmachun Watershed Through an Intensive Monitoring (설마천 유역 범륜사사면의 토양수분 시공간 집중변화양상의 측정)

  • Lee, Ga-Young;Kim, Ki-Hoon;Oh, Kyung-Joon;Kim, Sang-Hyun
    • Journal of Korea Water Resources Association
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    • v.38 no.5 s.154
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    • pp.345-354
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    • 2005
  • Time Domain Reflectometry (TDR) with multiplex system has been installed to configure the spatial and temporal characteristics of soil moisture at the Bumreunsa hillslope of Sulmachun Watershed. An intensive surveying was performed to build a refined digital elevation model (DEM) and flow determination algorithms with inverse surveying have been applied to establish an efficient soil moisture monitoring system. Soil moisture data were collected through intensive monitoring during 380 hrs in November of 2003. Soil moisture data shows corresponding variation characteristics of soil moisture on the upper, middle and lower parts of the hillslope which were classified from terrain analysis. Measured soil moisture data have been discussed on the context of physical process of hydrological modeling.