• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.32-40
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• 2022

In this study, the appropriate unit cost in grassland establishment was redeveloped by the grassland establishment method and work criteria. The grassland establishment method was divided into tillage establishment (all logging) and no-tillage establishment (all logging and partial logging). The price for the work criteria by the establishment method was presented for each permission/authorization and establishment work. In permission/authorization for grassland establishment, the cost of each work criteria was of environmental impact (small scale environmental impact) assessment, disaster impact assessment, cadastral serving fee, forest survey, and connection fee for control of mountainous districts. In establishment was of logging, cleaning/gruffing, plowing/soil preparation, seeding, fertilization, livestock manure compost, seed, herbicide, labor cost (fertilizer, seed and herbicide), soil consolidation, cattle trail, and fence. The unit cost of grassland establishment was KRW 115,894,212 for the tillage establishment, and KRW 110,281,572 and KRW 106,680,122 for the all and partial logging of the no-tillage establishment, respectively. The current study redeveloped the establishment method, work criteria, and estimation of the unit cost of grassland establishment. It can be usefully used to carry out government projects to support related to establishment and maintenance of grassland.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.443-449
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• 2004

In this paper, we established a simulation model for transport vehicle that carries the container transportation between apron and yard block on automated container terminal with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by productivity of container cranes at apron, and though there are enough support of transport vehicles and yard cranes, can improve the productivity of container cranes. Especially, transport vehicle is very important factor in productivity of container cranes and has variable work productivity according to loading and unloading situation of container cranes. Therefore, a method that can estimate work productivity of transport vehicle efficiently is required. We analyzed work productivity of transport vehicle using simulation model that has state transition of transport vehicle. We performed various simulation experiment and analyzed work productivity of transport vehicle and calculated the required number of transport vehicle by container crane additionally.

• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.44-52
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• 2012

In the cost management of public construction projects, it is an important issue to develop an adequate cost data for estimating the predetermined amount by various methods. For a long time, a standard of estimation in korea is used as a basis for estimating the predetermined amount of public construction. However, they did not have a reasonable cost data based on a labor and equipment productivity analysis. For this reason, it is difficult to make a reasonable and efficient estimation of the costs, and this situation presents an urgent need for more accurate cost data to use in an early phase. This study analyzed the productivity of form work by the CYCLONE model, and presented the model on the number of optimal labor through sensitivity analysis. This CYCLONE model can be useful in analyzing productivity on the various sizes of form. Also, the regression model to estimate the daily output can be used in predicting the amount of labor. Considering the work duration in the regression model is expected to make the daily output estimation much more accurate.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.47-63
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• 2023

In smart ports and port automation, the number of vertically deployed container terminals is growing. The purpose of this study is to analyze the productivity of horizontally arranged and vertically arranged container terminals by comparing the main ship operation time, and to recommend future strategies for increasing the operational efficiency of vertically configured container terminals. To achieve our goal, we chose two terminals representating each type, and collected berth allocation status data from 2018 to 2022. Then we analyzed the data using the Accelerated Failure Time (AFT) model, a parametric survival analysis technique. Under the assumption that the working circumstances of the C/C (Container Crane) are the same, we find that the productivity of on-board work of the vertically placed container terminal is higher than that of the horizontally placed container terminal. Our result also shows that the productivity is reduced during the COVID-19 period and the European ships show lower onboard work time. On the basis of these findings, we propose strategies to improve the productivity of vertical container terminals.

• Journal of Biosystems Engineering
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• v.15 no.3
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• pp.244-256
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• 1990

This study was conducted to select the optimal machinery systems for the Mechanized Farming Groups (MFG) by their sizes. In order to achieve the objective, a survey and systems analysis were taken for 50 MFG of Chungnam province. Then a mathematical model was developed. Based on it, a computer program (MFSDINGP) was developed by the Iterative Nonlinear Goal Programming (INGP) and Hooke & Jeeves pattern search algorithm. Using MFSDINGP, optimal machinery systems were selected and presented with annual costs of machinery for the sizes of 5-40 ha of MFG.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.473-476
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• 2007

본 논문에서는 LBT(Listen Before Talk) 방식을 사용하는 ZigBee와 FH(Frequency Hopping) 방식을 사용하는 DCP, RFID, Bluetooth 등의 소출력 무선기기가 공유주파수대역에 공존할 경우 요구되는 적정 채널수를 산출하고 전체 공유주파수대역폭 산출법을 제시하였다. 한정된 주파수 대역에서 LBT 및 FH 방식을 사용하는 총 User 수가 포용되는 공유주파수대역폭 산출은 중요한 작업이다. 소출력 무선기기 시스템의 간섭 회피 기술로 사용되는 FH 방식과 LBT 방식에 대기행렬이론(Queueing Theory)을 적용하였으며, 주위의 전파환경을 감지하여 유휴 주파수대역을 찾아 데이터전송을 시도하는 LBT 방식은 random하게 주파수채널을 이동하며 통신을 시도하는 FH 방식과는 구별된다. 채널수 별 User의 통신시도 시간간격을 통계적으로 처리하여 Throughput을 분석한 결과, Throughput 70% 조건에서 FH 방식과 LBT 방식을 사용하는 250mW 소출력 무선기기들이 공존하는 공유주파수대역의 적정 채널수는 30개를 가지며, 전체 공유주파수대역폭은 채널수에 채널당 대역폭의 곱으로 산출이 가능하다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.575-578
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• 2004

Since a construction project is a series of works that utilizes resources to accomplish the project goal for a given time period, efficient resource management is a prerequisite for the success of the project. Two major areas of resource management are resource constrained scheduling focusing on the limited resource availability and resource leveling focusing on smoothing resource usage pattern on the fixed project completion time. It is not available, however, to apply both techniques to a project at the same time. This paper proposes a model to enhance the minimum moment algorithm of resource leveling, aiming to find an efficient usage of resources and an appropriate project completion time. A survey is performed to evaluate the major five factors using the AHP.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.493-494
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• 2021

항공 산업의 발전으로 개인의 해외여행의 부담이 낮아져 각국의 왕래가 많아지고 있으며 사람들이 느끼는 국가 간 거리감이 크게 축소되고 있다. 또한, 화물의 운송이 활발해지며 이와 함께 화물 항공 물류량이 크게 늘어가고 있다. 항공물류 절차 중 화물적재는 사람들이 작업하고 적재 실수로 인한 사고들이 발생하는 것을 알고 이를 개선하고자 본 연구를 선정하게 되었다. 본 연구를 통해 구현할 '항공기 자동 중량평형 알림 시스템'은 평형 상태일 때 항공기 화물실 각 위치의 무게를 측정하고 적정 평형 값을 계산해 스크린에 출력하고 적정 평형 한계를 초과할 경우 경고음과 스크린을 통해 적정 평형이 아님을 알리는 방식으로 작동된다. 이러한 방식을 통해 조종사와 운항관리사, Load Master들이 잘못된 적재로 인한 화물의 위치를 수정하여 화물적재 과정의 안전핀 역할을 할 수 있다. 따라서 우리는 과제 개발에 따른 기대효과 로 항공사에서 여객기, 대형 수송기 등에 시스템을 추가하여 평형으로 인한 사고를 미연에 방지할 수 있다.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.300-309
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• 2017

The productivity, cost, and optimal forest road network density for tree-length yarding with K301-4 and HAM300 tower yarders were analyzed. The results showed that productivity decreased as the yarding distance increased. The productivity of the K301-4 was greater than that of the HAM300 as the maximum yarding distance was longer than 34 m. This difference increased as the load volume increased. As the K301-4 yarder had a higher purchase price and it took more time to set up compared to the HAM300, the HAM300 was cost effective. Therefore, in oder to introduce tower yarders to reduce operational cost, it is effective to increase the load volume during operations and to utilize the road network repeatedly for a long period.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.47-54
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• 2004

Recently, many high-rise buildings have been constructed, and are under construction. And a high-rise building with more than 100 floors is under planning. From site logistics management point of view, it is very important to manage vertical transportation of resource (e.g., material, equipment and construction labors) in high-rise building construction. The higher the building is constructed, the more important it is to manage for vertical transportation of it. In case of labors, vertical movement needs longer time in high-rise building construction than in low-rise. This results in low productivity and work efficiency of the construction. Therefore, this study presents a process of a vertical movement plan for labors using discrete-event simulation. And then the process applies to MT 130 project, which is a virtual high-rise building construction project.