当代物流学(第11讲)
合集下载
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
di ，直到（X，Y） 的变动满足要求。
例题：某企业的两个工厂分别生产A、B两种产品, 供应三个市场（M1 ,M2 , M3 ）, 已知条件如图及 下表所示。现需设置一个中转仓库， A、B两种产
品通过该仓库间接向三个市场供货。请使用重心
法求出仓库的最优选址。
节点i
产品 运输总量 运输费率￥ 坐标Xi 坐标Yi
Weighted Center-of-Gravity Approach
To illustrate the weighted center-ofgravity approach, consider the preceding five-store example, but modify the assumption that each store receives the same volume.
3.2 miles east of point zero.
Because it’s not likely that each store will place equal demands on a prospective warehousing facility, the center-of-gravity approach can be easily modified to take volume into account ―― the weight center-ofgravity approach.
如何回答？
问题描述：设有一系列点分别代表供给 点和需求点，各自有一定量货物需要以 一定的运输费率运向位置待定的仓库（ 或从仓库运出），该仓库如何选址？
模型建立： min TC = i V i R i d i TC——运输总成本；
V i ——节点I的运输总量； R i ——待选址设施到节点的运输费率； d i ——待选址设施到节点的距离。
Adjustments may have to be made to take into account real-world considerations such as the cost and quality of transport services, taxes, wage rates in particular locations, volume discounts, and the fact that transport rates taper with increased distances.
1
3
1
3
(3x3)=9
2
3
3
5
(3x5)=15
3
2
4
4
(2x4)=8
4
1
2
2
(1x2)=2
5
3
6
6
(3x6)=18
East x volume
(1x3)=3 (3x5)=15 (4x4)=16 (2x2)=4 (6x6)=36
Total Weighted average
20
52
74
2.6
3.7
8-19
Center-of-gravity approach can be used for locating a single facility so that the distance to existing facilities is minimized.
Figure 8-1 shows a grid system placed over a map of five existing retail stores. At issue is where a warehousing facility to serve these stores should be located.
CHAPTER 8
Distribution Center, Warehouse, and Plant Location
Learning Objectives
To understand the economic importance of facility location.
To learn of traditional site location theory on plant/warehouse location.
iViRi /di
求解步骤：1）确定已知的供给点和需求点的坐标
、运输量及线性运输费率；2）忽略距离di ，根据 重心公式求得待选址设施的初始坐标（X0 ，Y0 ）；
X0＝—iV—iViRi—RiXi i
Y0＝—i—ViViR—iRiY—i i
3）根据第二步求得的（X0 ，Y0）计算出di ;4）将di 代入公式求出修正的（X，Y） ；5）反复迭代计算
模型求解： （X，Y） ——待选址设施的坐标；
（Xi ，Yi）——已知的供给点和需求点坐标； 距离公式d i =k [(Xi －X)2 +(Yi －Y)2 ] 1/2 k——模型中坐标单位与实际空间距离的比例尺；
iViRiXi/di X＝ ————
iViRi /di
iViRiYi/di Y＝ ————
The procedure is repeated to calculate the east weighted center-ofgravity location.
Table 8-1: Weighted Center-of-Gravity Example
Store North East Mo. volume North x location location (tons) volume
Assume that store 1 receives 3 tons of shipment; store 2 receives 5 tons of shipment; store 3 receives 4 tons of shipment; store 4 receives 2 tons of shipment; store 5 receives 6 tons of shipment.
P1
A 2000
0.05
3
8
P2
B 3000
0.05
8
2
M1
A、B 2500
0.075
2
5
M2
A、B 1000
0.075
6
4
M3
A、B 1500
0.075
8
8
P1 M1
M2
M3 P2
求解过程：忽略距离
di ，根据重心公式求 得待选址设施的初始 坐标（X0 ，Y0 ）；
X0＝—iiViV—iRiR—iXi —＝5.16
Assuming that each store receive the same volume and that straight-line distances are used, the best (lowestcost) for a warehousing facility to serve the five stores is determined by taking the average north-south coordinates and the average east-west coordinates of the retail stores.
在使用中，列出主要选址决策因素 ，建立选址因素的加权矩阵，将这 些因素的权重乘以各因素得分，然 后加总得到该选址方案的最后评分 ，决策者可以根据加权评分判断备 选方案的优劣。
使用因素评分法选址的步骤如下： 1)给出备选地点；2)列出影响选址 的各个因素；3)给出每个因素的分 值范围；4)由专家对各个备选地点 针对各个因素进行评分；5)将每一 地点各因素的得分相加，求出总分 后加以比较，得分最多的地点中选 。
Center-of-Gravity Approach
Grid systems can be used to determine an optimal location (defined as the lowest cost) for one additional facility.
Grid systems are checkerboard patterns that are placed on a map, as in Figure81, and the grid is numbered in two directions: horizontal and vertical.
Other Facility Issues
Facility relocation
In theory, the relocation decision involves a comparison of the advantages and disadvantages of a new site to the advantage and disadvantage of an existing location.
Y0＝—i—ViViR—iRiY—i i ＝5.16
代入（X0 ，Y0）计算出di ;将di代入公式求出修
正的（X，Y） ；反复迭代计算di ，直到（X，Y） 的 变动满足要求。
因素评分法
因素评分法在常用的选址方法中是使 用最广泛的一种，它以简单易懂的模 式将各种不同因素综合起来。最大的
缺点是没有将每种因素所关联的成本考 虑在内。
精确重心法
精确重心法是一种以微积分为基础的 模型，用来找出使运输成本最小的设 施位置。该模型简单，属于静态连续 选址模型，容易找到最优解。可用于 工厂、车站、仓库或零售/服务设施选 址。
假设条件：
1)假设需求量集中于某一点，实际上需求来 自分散于一定区域内的多个消费点；2)一般 根据可变成本进行选址，忽略了不同地点建 设仓库的资本成本，以及相关的经营成本（ 如劳动力、库存持有成本）；3)假设运输成 本随运距成比例增加；4)模型中仓库与其他 网络节点之间的路线为直线；5)静态选址假 设。
To calculate the north weighted centerof-gravity location, each north coordinate is multiplied by the corresponding volume and these values are summed. This total is then divided by the sum of the monthly volume.
To describe the major factors that influence location decisions.
To explain system to determine the location that minimizes transportation costs.
8-2
Finding the Lowest-Cost Location
The average distance east is (1+2+3+4+6) or 16; 16 divided by 5 equals 3.2 miles.
Thus, the best (lowest-cost) location is one with coordinates 2.4 miles north and
Figure 8-1: Center-of-Gravity Location for a Warehouse Serving Five Retail Stores
8-11
In this example, t源自文库e average distance north is (3+1+3+2+3) or 12.This figure is divided by the number of stores (5), resulting in a north location 12/5 or 2.4 miles.
Traditional site location theory can be used to show that one or several locations will minimize transportation costs.
While most solutions to locational problems currently involve computer analysis, such analysis may not be needed if the relevant parameters are not too complex.
例题：某企业的两个工厂分别生产A、B两种产品, 供应三个市场（M1 ,M2 , M3 ）, 已知条件如图及 下表所示。现需设置一个中转仓库， A、B两种产
品通过该仓库间接向三个市场供货。请使用重心
法求出仓库的最优选址。
节点i
产品 运输总量 运输费率￥ 坐标Xi 坐标Yi
Weighted Center-of-Gravity Approach
To illustrate the weighted center-ofgravity approach, consider the preceding five-store example, but modify the assumption that each store receives the same volume.
3.2 miles east of point zero.
Because it’s not likely that each store will place equal demands on a prospective warehousing facility, the center-of-gravity approach can be easily modified to take volume into account ―― the weight center-ofgravity approach.
如何回答？
问题描述：设有一系列点分别代表供给 点和需求点，各自有一定量货物需要以 一定的运输费率运向位置待定的仓库（ 或从仓库运出），该仓库如何选址？
模型建立： min TC = i V i R i d i TC——运输总成本；
V i ——节点I的运输总量； R i ——待选址设施到节点的运输费率； d i ——待选址设施到节点的距离。
Adjustments may have to be made to take into account real-world considerations such as the cost and quality of transport services, taxes, wage rates in particular locations, volume discounts, and the fact that transport rates taper with increased distances.
1
3
1
3
(3x3)=9
2
3
3
5
(3x5)=15
3
2
4
4
(2x4)=8
4
1
2
2
(1x2)=2
5
3
6
6
(3x6)=18
East x volume
(1x3)=3 (3x5)=15 (4x4)=16 (2x2)=4 (6x6)=36
Total Weighted average
20
52
74
2.6
3.7
8-19
Center-of-gravity approach can be used for locating a single facility so that the distance to existing facilities is minimized.
Figure 8-1 shows a grid system placed over a map of five existing retail stores. At issue is where a warehousing facility to serve these stores should be located.
CHAPTER 8
Distribution Center, Warehouse, and Plant Location
Learning Objectives
To understand the economic importance of facility location.
To learn of traditional site location theory on plant/warehouse location.
iViRi /di
求解步骤：1）确定已知的供给点和需求点的坐标
、运输量及线性运输费率；2）忽略距离di ，根据 重心公式求得待选址设施的初始坐标（X0 ，Y0 ）；
X0＝—iV—iViRi—RiXi i
Y0＝—i—ViViR—iRiY—i i
3）根据第二步求得的（X0 ，Y0）计算出di ;4）将di 代入公式求出修正的（X，Y） ；5）反复迭代计算
模型求解： （X，Y） ——待选址设施的坐标；
（Xi ，Yi）——已知的供给点和需求点坐标； 距离公式d i =k [(Xi －X)2 +(Yi －Y)2 ] 1/2 k——模型中坐标单位与实际空间距离的比例尺；
iViRiXi/di X＝ ————
iViRi /di
iViRiYi/di Y＝ ————
The procedure is repeated to calculate the east weighted center-ofgravity location.
Table 8-1: Weighted Center-of-Gravity Example
Store North East Mo. volume North x location location (tons) volume
Assume that store 1 receives 3 tons of shipment; store 2 receives 5 tons of shipment; store 3 receives 4 tons of shipment; store 4 receives 2 tons of shipment; store 5 receives 6 tons of shipment.
P1
A 2000
0.05
3
8
P2
B 3000
0.05
8
2
M1
A、B 2500
0.075
2
5
M2
A、B 1000
0.075
6
4
M3
A、B 1500
0.075
8
8
P1 M1
M2
M3 P2
求解过程：忽略距离
di ，根据重心公式求 得待选址设施的初始 坐标（X0 ，Y0 ）；
X0＝—iiViV—iRiR—iXi —＝5.16
Assuming that each store receive the same volume and that straight-line distances are used, the best (lowestcost) for a warehousing facility to serve the five stores is determined by taking the average north-south coordinates and the average east-west coordinates of the retail stores.
在使用中，列出主要选址决策因素 ，建立选址因素的加权矩阵，将这 些因素的权重乘以各因素得分，然 后加总得到该选址方案的最后评分 ，决策者可以根据加权评分判断备 选方案的优劣。
使用因素评分法选址的步骤如下： 1)给出备选地点；2)列出影响选址 的各个因素；3)给出每个因素的分 值范围；4)由专家对各个备选地点 针对各个因素进行评分；5)将每一 地点各因素的得分相加，求出总分 后加以比较，得分最多的地点中选 。
Center-of-Gravity Approach
Grid systems can be used to determine an optimal location (defined as the lowest cost) for one additional facility.
Grid systems are checkerboard patterns that are placed on a map, as in Figure81, and the grid is numbered in two directions: horizontal and vertical.
Other Facility Issues
Facility relocation
In theory, the relocation decision involves a comparison of the advantages and disadvantages of a new site to the advantage and disadvantage of an existing location.
Y0＝—i—ViViR—iRiY—i i ＝5.16
代入（X0 ，Y0）计算出di ;将di代入公式求出修
正的（X，Y） ；反复迭代计算di ，直到（X，Y） 的 变动满足要求。
因素评分法
因素评分法在常用的选址方法中是使 用最广泛的一种，它以简单易懂的模 式将各种不同因素综合起来。最大的
缺点是没有将每种因素所关联的成本考 虑在内。
精确重心法
精确重心法是一种以微积分为基础的 模型，用来找出使运输成本最小的设 施位置。该模型简单，属于静态连续 选址模型，容易找到最优解。可用于 工厂、车站、仓库或零售/服务设施选 址。
假设条件：
1)假设需求量集中于某一点，实际上需求来 自分散于一定区域内的多个消费点；2)一般 根据可变成本进行选址，忽略了不同地点建 设仓库的资本成本，以及相关的经营成本（ 如劳动力、库存持有成本）；3)假设运输成 本随运距成比例增加；4)模型中仓库与其他 网络节点之间的路线为直线；5)静态选址假 设。
To calculate the north weighted centerof-gravity location, each north coordinate is multiplied by the corresponding volume and these values are summed. This total is then divided by the sum of the monthly volume.
To describe the major factors that influence location decisions.
To explain system to determine the location that minimizes transportation costs.
8-2
Finding the Lowest-Cost Location
The average distance east is (1+2+3+4+6) or 16; 16 divided by 5 equals 3.2 miles.
Thus, the best (lowest-cost) location is one with coordinates 2.4 miles north and
Figure 8-1: Center-of-Gravity Location for a Warehouse Serving Five Retail Stores
8-11
In this example, t源自文库e average distance north is (3+1+3+2+3) or 12.This figure is divided by the number of stores (5), resulting in a north location 12/5 or 2.4 miles.
Traditional site location theory can be used to show that one or several locations will minimize transportation costs.
While most solutions to locational problems currently involve computer analysis, such analysis may not be needed if the relevant parameters are not too complex.