### 统计代写|运筹学作业代写operational research代考|Transportation Models

statistics-lab™ 为您的留学生涯保驾护航 在代写运筹学operational research方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写运筹学operational research代写方面经验极为丰富，各种代写运筹学operational research相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 统计代写|运筹学作业代写operational research代考|Concept of Assignment Problem

The assignment problem is a special class of LP problem. It deals with the situations in which resources are assigned to tasks or other work requirements. Typical examples include assignment of workers to tasks and assignment of machines to jobs. The objective is to yield an optimal matching of resources and tasks. Commonly used criteria are costs, profits, and time. The assignment problem can be described as follows. A company has a group of workers $(i=1,2, \ldots, n)$ and a set of tasks $(j=1,2, \ldots, n)$ to complete. The problem is how to assign $n$ workers to $n$ tasks at the minimum cost, $c_{i j}$. By introducing decision variables $x_{i j}$ to represent the assignment of worker $i$ to task $j$, the assignment model can be written as shown in Model 2.2.1.
Model 2.2.1 Standard assignment model
Minimize $z=\sum_{j=1}^{n} \sum_{j=1}^{n} c_{i j} x_{i j}$
subject to
$$\begin{gathered} \sum_{i=1}^{n} x_{i j}=1 \quad j=1,2, \ldots, n \ \sum_{j=1}^{n} x_{i j}=1 \quad i=1,2, \ldots, n \ \text { All } x_{i j} \geq 0 . \end{gathered}$$
Model 2.2.1 is referred to as the assignment model. Objective function $2.2 .1$ minimizes the total cost associated with worker $i$ performing task $j$.

## 统计代写|运筹学作业代写operational research代考|Example of Assignment Problem

Figure $2.6$ shows an assignment network in which there are five workers and five tasks. The cost associated with worker $i$ performing task $j$ are shown above the arcs, or arrows. For example, it costs 8 units of dollars for worker 1 to complete task 1 . The capacity of each worker, $s_{j y}$ and the demand of each task, $d_{j}$, are also shown. Because there is only one worker $i$ available for performing a particular task $j$, all $s_{i}$ and $d_{j}$ equal 1 .

This assignment network or problem can be represented by a tableau as shown in Table 2.3. The upper-right corner of each cell in the tableau represents the cost, $c_{i j}$.

By introducing decision variables $x_{i j}$ to represent the assignment of worker $i$ to task $j$, this assignment problem can be formulated as shown in Model $2.2 .2$.
Model 2.2.2 An example of formulation of assignment problem
\text { Minimize } \begin{aligned} & 8 x_{11}+6 x_{12}+2 x_{13}+4 x_{14}+3 x_{15} \ &+6 x_{21}+7 x_{22}+11 x_{23}+10 x_{24}+7 x_{25} \ &+3 x_{31}+5 x_{32}+7 x_{33}+6 x_{34}+4 x_{35} \ &+5 x_{41}+10 x_{42}+12 x_{43}+9 x_{44}+7 x_{45} \ &+7 x_{51}+12 x_{52}+5 x_{53}+7 x_{54}+8 x_{55} \end{aligned}

Constraint sets $2.2 .5$ to $2.2 .9$ ensure that each task is to be performed by exactly one worker. Constraint sets $2.2 .10$ to $2.2 .14$ ensure that each worker is to be assigned to exactly one task. Although Model 2.2.2 is an LP model, the optimal solution must be integral because the assignment model holds the integrality property.

## 统计代写|运筹学作业代写operational research代考|SAS Code for Assignment Problem

ORASSIGN solves assignment problems, in which one set of items must be assigned to another (e.g., tasks to specific workers) at the lowest total cost (see program “sasor_2_2.sas”).
Figure $2.7$ illustrates the data flow in the ORASSIGN. It shows:

• The cost matrix that is required for ORASSIGN-in this case, the cost associated with worker $i$ performing task $j$
• The macros (\%data, \%model, and \%report)
• The macro variables needed to be set before running the code
• The results datasets that are available for print or can be used for further analysis
In the rest of this section, the procedure for implementing ORASSIGN, together with an example, is explained. The ORASSIGN runs three macros: data-handling (\%data), model-building (\%model), and report-writing (\%report).

## 统计代写|运筹学作业代写operational research代考|Concept of Assignment Problem

∑一世=1nX一世j=1j=1,2,…,n ∑j=1nX一世j=1一世=1,2,…,n  全部 X一世j≥0.

## 统计代写|运筹学作业代写operational research代考|Example of Assignment Problem

最小化 8X11+6X12+2X13+4X14+3X15 +6X21+7X22+11X23+10X24+7X25 +3X31+5X32+7X33+6X34+4X35 +5X41+10X42+12X43+9X44+7X45 +7X51+12X52+5X53+7X54+8X55

## 统计代写|运筹学作业代写operational research代考|SAS Code for Assignment Problem

ORASSIGN 解决了​​分配问题，其中必须以最低的总成本将一组项目分配给另一组（例如，将任务分配给特定的工人）（参见程序“sasor_2_2.sas”）。

• ORASSIGN 所需的成本矩阵——在这种情况下，与工人相关的成本一世执行任务j
• 宏（\%data、\%model 和 \%report）
• 运行代码前需要设置的宏变量
• 可用于打印或可用于进一步分析的结果数据集
在本节的其余部分中，将解释实施 ORASSIGN 的过程以及示例。ORASSIGN 运行三个宏：数据处理 (\%data)、模型构建 (\%model) 和报告编写 (\%report)。

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。