Globalization push container terminal grown rapidly in decade. To fulfill the future traffic requirement, this study highlights marginal expansion planning of infrastructure in a container terminal. By using marginal ...Globalization push container terminal grown rapidly in decade. To fulfill the future traffic requirement, this study highlights marginal expansion planning of infrastructure in a container terminal. By using marginal approach, the expansion plan can be determine correctly and economically stage by stage. A mathematical model has generated to calculate the expansion size, expansion time, interval of expansion, expansion cost, and significant of expansion for each infrastructure respectively. It recommended determining the expansion plan for each infrastructure respectively. This is because one of the infrastructures needs to be expanding but the other may not. The generated model was verified with others model and validated with case study to investigate the practicability of the model. The model serves as expansion decision making tools to assist port expansion planners.展开更多
Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level...Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level trade-offs between timber production and production of core area of older forest (COF) for the region. COF is an important metric for wildlife habitat. Emphasis is on better understanding potential gains from both coordinated planning at the site-level where ownerships share stand boundaries and from coordinated planning at a broader policy level involving assumed values of COF by the public. The study area involves over 300,000 ha, 150,000 analysis units and a 100-year planning horizon. Methods: The concept of influence zones in modeling spatial interdependencies is described and implemented. The estimated total area of COF is assumed an important landscape metric for forest wildlife habitat condition for each forest planning period. COF has a surrounding buffer protecting it from edge effects. Differences are recognized between COF condition requirements and condition requirements for its surrounding buffer. A spatially-explicit harvest scheduling model is applied in conjunction with moving-windows techniques of GIS to find near-optimal management schedules for the large landscape. Multiple model runs are examined to help better understand both potential gains from coordinated planning and the tradeoffs between timber and COF production. Results: Results demonstrate the ability to incorporate detailed site-level COF production into management scheduling models for broad, landscape-level planning. For the study area and the assumed COF definitions, substantially larger gains are possible by coordinating COF value assumptions across ownerships, as compared to possible gains from coordinating on-the-ground management activities in areas involving shared stand boundaries. Although a general map of the study area shows a definite intertwining mosaic of ownership by the two large public agencies, a detailed breakdown of influence zone information shows that a low percentage of the land is influenced by both of these ownerships for COF production. Conclusions: This research helps illuminate potential large gains from coordinated planning at a broad policy level by large public ownerships through coordination of assumed COF values. For the study area, these gains are substantially greater than gains from combined modeling efforts addressing spatial detail and shared stand boundaries or neighborhoods. From a practical standpoint, this is important, as spatial detail adds substantially to model size, making combined analysis a major undertaking. Detailed site-level coordination also presents operational challenges in schedule implementation.展开更多
Determining the size of maintenance workforce is an essential element of maintenance planning. It is important for performing maintenance programs perfectly. However, it is a complex and challenging problem since it i...Determining the size of maintenance workforce is an essential element of maintenance planning. It is important for performing maintenance programs perfectly. However, it is a complex and challenging problem since it involves the consideration of several important factors. The mathematical model developed in this paper aims at finding out the optimal size of the maintenance workforce taking into account all of the important factors that affect this size. It is based on determining the needed number of workers with different skill levels and from different sources to meet maintenance workload of different grades that is to be performed in a specified planning horizon with minimum cost acquired.展开更多
针对传统快速扩展随机树(Rapidly-Exploring Random Tree,RRT)算法在多维环境下固定步长调试耗时长、搜索效率低的问题,提出了一种适用于机械臂的范数自适应步长RRT算法。建立6自由度UR5机械臂的运动学模型并进行正运动学分析,得到其雅...针对传统快速扩展随机树(Rapidly-Exploring Random Tree,RRT)算法在多维环境下固定步长调试耗时长、搜索效率低的问题,提出了一种适用于机械臂的范数自适应步长RRT算法。建立6自由度UR5机械臂的运动学模型并进行正运动学分析,得到其雅可比矩阵;结合范数不等式和雅可比矩阵,建立机械臂工作空间与关节空间的步长映射关系,在动态改变关节空间搜索步长的同时,保证碰撞检测的有效性。仿真分析结果表明,范数自适应步长RRT算法比传统固定步长RRT算法搜索效率高且无需手动调试步长,路径搜索时间缩短了29.32%,提高了机械臂路径规划的效率。展开更多
文摘Globalization push container terminal grown rapidly in decade. To fulfill the future traffic requirement, this study highlights marginal expansion planning of infrastructure in a container terminal. By using marginal approach, the expansion plan can be determine correctly and economically stage by stage. A mathematical model has generated to calculate the expansion size, expansion time, interval of expansion, expansion cost, and significant of expansion for each infrastructure respectively. It recommended determining the expansion plan for each infrastructure respectively. This is because one of the infrastructures needs to be expanding but the other may not. The generated model was verified with others model and validated with case study to investigate the practicability of the model. The model serves as expansion decision making tools to assist port expansion planners.
基金funded jointly by the Minnesota Forest Resources Council,the University of Minnesota North Central ResearchOutreach Centerand the Interagency Information Cooperative of the Department of Forest Resources,University of Minnesota
文摘Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level trade-offs between timber production and production of core area of older forest (COF) for the region. COF is an important metric for wildlife habitat. Emphasis is on better understanding potential gains from both coordinated planning at the site-level where ownerships share stand boundaries and from coordinated planning at a broader policy level involving assumed values of COF by the public. The study area involves over 300,000 ha, 150,000 analysis units and a 100-year planning horizon. Methods: The concept of influence zones in modeling spatial interdependencies is described and implemented. The estimated total area of COF is assumed an important landscape metric for forest wildlife habitat condition for each forest planning period. COF has a surrounding buffer protecting it from edge effects. Differences are recognized between COF condition requirements and condition requirements for its surrounding buffer. A spatially-explicit harvest scheduling model is applied in conjunction with moving-windows techniques of GIS to find near-optimal management schedules for the large landscape. Multiple model runs are examined to help better understand both potential gains from coordinated planning and the tradeoffs between timber and COF production. Results: Results demonstrate the ability to incorporate detailed site-level COF production into management scheduling models for broad, landscape-level planning. For the study area and the assumed COF definitions, substantially larger gains are possible by coordinating COF value assumptions across ownerships, as compared to possible gains from coordinating on-the-ground management activities in areas involving shared stand boundaries. Although a general map of the study area shows a definite intertwining mosaic of ownership by the two large public agencies, a detailed breakdown of influence zone information shows that a low percentage of the land is influenced by both of these ownerships for COF production. Conclusions: This research helps illuminate potential large gains from coordinated planning at a broad policy level by large public ownerships through coordination of assumed COF values. For the study area, these gains are substantially greater than gains from combined modeling efforts addressing spatial detail and shared stand boundaries or neighborhoods. From a practical standpoint, this is important, as spatial detail adds substantially to model size, making combined analysis a major undertaking. Detailed site-level coordination also presents operational challenges in schedule implementation.
文摘Determining the size of maintenance workforce is an essential element of maintenance planning. It is important for performing maintenance programs perfectly. However, it is a complex and challenging problem since it involves the consideration of several important factors. The mathematical model developed in this paper aims at finding out the optimal size of the maintenance workforce taking into account all of the important factors that affect this size. It is based on determining the needed number of workers with different skill levels and from different sources to meet maintenance workload of different grades that is to be performed in a specified planning horizon with minimum cost acquired.
文摘针对传统快速扩展随机树(Rapidly-Exploring Random Tree,RRT)算法在多维环境下固定步长调试耗时长、搜索效率低的问题,提出了一种适用于机械臂的范数自适应步长RRT算法。建立6自由度UR5机械臂的运动学模型并进行正运动学分析,得到其雅可比矩阵;结合范数不等式和雅可比矩阵,建立机械臂工作空间与关节空间的步长映射关系,在动态改变关节空间搜索步长的同时,保证碰撞检测的有效性。仿真分析结果表明,范数自适应步长RRT算法比传统固定步长RRT算法搜索效率高且无需手动调试步长,路径搜索时间缩短了29.32%,提高了机械臂路径规划的效率。
