欢迎加入中国茉莉花行动部落
我们来自同一个部落,那里毒蛇横行。
我们播种茉莉,为了呼吸自由的芳香。
我们移植鲜花,为了拥抱春天的曙光。
Tuesday, May 2, 2023
追忆当年教科书
Monday, May 1, 2023
三年前我对各主要国家新冠死亡人数的预估
上图是我在2020年5月5日文章的部分截屏。那是预估半年后的死亡总数。如果将这些数字乘以2,可以看作是一年的新冠死亡人数,将上述数字乘以7,就可以作为到达2023年5月的新冠死亡人数。而按照我当时估算,全球新冠病人的死亡概率会高达21%,但美国这几个疫情泛滥大国的新冠死亡率是在10%左右。那么,这些数字还应该被除2。由此估算出的到达2023年5月的各国新冠死亡人数见下表。目前的新冠死亡人数同我的预估基本上相当。
就因为我修改两个错别字,徐水良和杨巍就对我辱骂三年
徐水良说我不懂统计学,我可以承认徐水良最懂统计学
三年前我用数学模型预估美国新冠死亡每年24万,今日应该是105万!
上图是我在2020年5月5日文章的部分截屏。那是预估半年后的死亡总数。如果将这些数字当作是一年的新冠死亡人数,将上述数字乘以4,就可以作为到达2023年底的新冠死亡人数,见下表。目前的新冠死亡人数同我的预估基本上相当。
Friday, March 10, 2023
诚请数学高手对我的这篇学术论文批评指正
A Mathematic Model for Supply-Demand Equilibrium and the Optimal Solution for Labor Assignment
- Gang Liu
Supply function and Production Possibility Frontier (PPF) are basic concepts in Economics. We present a model that can give mathematic formula for PPF and the supply as a function of the price vector and capability parameters. With this Supply function, the generic Supply-Demand equilibrium problems can be solved numerically. We apply the supply-demand equilibrium to give optimal solutions for team work management problems or labor assignment problems. Concrete examples are given for managing an engineer team in Boeing Corporation.
Keywords: Resource Allocation, Labor Assignment, Teamwork Management, Supply Function, Production Possibility Frontier, Supply-Demand equilibrium
Cite this paper: Gang Liu , A Mathematic Model for Supply-Demand Equilibrium and the Optimal Solution for Labor Assignment, American Journal of Economics, Vol. 4 No. 2, 2014, pp. 83-98. doi: 10.5923/j.economics.20140402.01.
Article Outline
1. Introduction
- Production Possibility Frontier (PPF) is one of the basic concepts in Economics. PPF can be simply defined as the boundary of frontier of the economy’s production capabilities. Most of Economic books normally have a whole chapter to discuss PPF and its applications [1, 4, 10, 11]. Most of these text books discuss the PPF and supply function for two products and in qualitative format, as shown in Figure 1. It is well-known that the PPF is convex and the supply-price curve is an upward-sloping curve. However, no one has given the PPF nor supply function in mathematic formats. The law of supply and the law of supply-demand equilibrium are basic laws in modern economics. However, without knowing the supply function in mathematic format, these laws can be only discussed quantitatively, and the general supply-demand equilibrium cannot be solved numerically.In early 2002, we have given the PPF and supply function in mathematic format for any number of products [6]. In this paper, we first introduce the model that can formulate the PPF in mathematic format, and then derive the supply as a function of the prices of all products. Some of the basic economic theorems can be derived from the PPF formula, such as the convexity of the PPF curve, the Law of Supply, as well as supply elasticity. We also proposed methods for solving the general supply-demand equilibrium numerically.There are wide applications of the proposed PPF functions. As an example, we apply the PPF function and the Supply-Demand equilibrium equation to give optimal solution for team work management and labor assignment problems. Our analysis and test results show that the proposed model can improve production efficiency by 40% for most of the team work management problems.The rest of the paper is organized as follows. Section 2 introduces some useful notations and definitions. Section 3 formulates the PPF and the supply function for a micro system. Section 4 further formulates the PPF and the supply function for a macro system. Section 5 discusses the lower Production Possibility Frontier. Section 6 discusses the Law of Supply and the Elasticity of Supply. Section 7 introduces two methods for solving the supply-demand equilibrium. Section 8 introduces two special production possibility curves that can be used to show how efficiency of the PPF. Section 9 applies our supply function to a dummy system to show concrete PPF curves and supply curves. Section 10 discusses the best scenario and the worst scenario. Section 11 applies our model to solve the labor assignment problem for a labor oriented team. Section 12 shows a concrete example of labor assignment problem for project oriented team. In Section 13 and 14, we analyze the efficiency improvements by the optimal solution. Section 15 introduces two management methods that can reach the optimal solution for team work management. Conclusions are presented in Section 16.
2. Notations and Definitions
- In order to describe our model and the PPF curve, let us first introduce some notations and definitions.
2.1. Notations
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2.2. Definitions
- Definition: Micro System and Macro System: An economic system is called a macro system if it contains some sub-systems, such as the system
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2.3. Known Parameters and Unknowns
- Using the above notations, we can list the input data in table format. Basically, we assume the following data are known input data:
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3. Micro PPF and Micro Supply Function of a Micro System
- For any micro system
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4. Macro PPF and Macro Supply Function of a Macro System
- We have formulated the micro PPF
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5. Macro Worst Production Possibility Frontier of the Macro System
- Similarly, we can formulate the Worst Production Possibility Frontier (WPPF) for the micro as well as the macro system. Let
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6. The Supply Elasticity and the Law of Supply
- The Supply Elasticity is defined as the absolute value of the ratio of the percentage change in quantity supplied to the percentage change in price, which brings about the change in supply. Let
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![]() | (18) |
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7. Supply-Demand Equilibrium
- Supply-Demand Equilibrium is one of the most important theorems in Economics. It states that Equilibrium is defined to be the price-quantity pair where the quantity demanded is equal to the quantity supplied, represented by the intersection of the demand and supply curves. The general format for the Supply-Demand Equilibrium can be expressed as:
![]() | (22) |
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![]() | (23) |
7.1. Solving the General Equilibrium as an Equation Problem
- By combining Equation (23) and Equation (17), the General Equilibrium Equation can be formulated as the following equation problem:
![]() | (24) |
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7.2. Solving the General Equilibrium as an Linear Programming Problem
- The General Equilibrium Equation (23) can also be formulated as the following optimization problem:
![]() | (25) |
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8. Some Special Production Possibility Curves
- In this section, we introduce two special scenarios with special production possibility curves. These curves can be used to compare with the PPF and can show how efficiency of the production states on the PPF.
8.1. Linear Production Possibility Frontier
- We have introduced the micro vertex points as shown in Equation (5). A plane curve can be formulated by passing through these vertex points as following:
![]() | (26) |
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![]() | (27) |
![]() | (28) |
![]() | (29) |
8.2. Self Sufficient Scenario
- Another special scenario is the so called Self Sufficient case, in which every micro system just simply works on itself to provide all products with the amounts to be proportional to the requested demands. Within this scenario, there is no cooperation among micro systems. Let us call the PPF Curve for this scenario as SPPF. Let
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![]() | (30) |
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![]() | (31) |
9. A Dummy System with Dummy Data
- In order to give concrete examples to demonstrate our model and methodology, let us create a dummy system with dummy data. The dummy system
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![]() | Figure 2. The micro PPF![]() ![]() ![]() ![]() |
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10. The Best and the Worst Scenarios
- Suppose each of the micro system
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![]() | (32) |
11. Application 1: Labor Assignment for Labor Oriented Team
- The mathematic formula for the Macro PPF and the supply function may have lot of applications and can improve the production efficiency significantly. Here we just introduce one of the applications of the macro PPF and the supply function: finding the optimal solution for team work management problems.We have developed a software tool that can find optimal solution for labor assignment problems by solving equation problem listed in Equation (24), or by solving linear programming problem as listed in Equation (25).By applying this software tool to the Carpenter team with the input data as listed in Table 1, we find the optimal solution as shown in Table 2.The solution given in Table 2 tells us at least the following information:
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12. Application 2: Labor Assignment for Project Oriented Team
- Application 1 gives an example of a team working on products, which is more applicable to a labor oriented team.A product oriented team is basically a team working on products and the demands can be simply formulated as the amounts of the products. A project oriented team is a team working on projects, while each project is required to be delivered in a given deadline. For a project oriented team, the capability parameter
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13. Production Efficiency Improvement for the Carpenter Team
- Note that, even with the worst scenario case, all team members have worked hard to reach their micro PPF states. In other words, although all team members have exhausted all of their resources to work on the requested products, the production output are very different for the macro system. The inefficiency for the worst scenario is completely due to improper management. With proper arrangement, we can have the team to improve production efficiency by 148% compared with the worst scenario.Table 7 lists the macro supplies for the optimal solution, the worst scenario solution, the Linear Macro Supply scenario, as well as the Self-Sufficient scenario. It also lists the improved production efficiency ratios by comparing with the Self-Sufficient scenario as well as the Linear Macro Supply scenario.
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14. Estimate the Improved Production Efficiency for Generic Cases
- As discussed in the previous sections, by applying our optimal management method, the Carpenter team can improve its production efficiency by 43%. That is amazing! However, people might argue that the Carpenter team is just a special case. In this section, we estimate the production efficiency improvement ratio that can be brought by the optimal solution for generic cases. Our analysis shows that the optimal solution can really improve production efficiency by 40% for most of the team work management problems.To simplify our analysis, we assume the demand vector as
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15. Micro and Macro Management
- By applying the proposed method and the software tool, we can find the optimal solution for the team work management, or labor assignment problems. Suppose you are the team manager, how are you going to manage your team to reach the optimal management? Here we propose two management methods: Micro Management and Macro Management.
15.1. Micro Management
- Our optimal solution for team work management problems, as shown in Table 2 and Table 4, lists all the micro information for each team member, including micro supply amount
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15.2. Macro Management
- Our optimal solution for team work management problems, as shown in Table 2 and Table 4, also gives the intrinsic prices
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16. Conclusions
- The main contributions of this paper include a new model that can formulate the Supply function and the Production Possibility Frontier as a function of the capability parameters and the price vector. The Law of Supply, the supply elasticity can be easily derived from the proposed model. Another contribution is the methods for solving the Supply-Demand equilibrium. Lastly, we present a model and method that can give optimal solution for labor assignment and team work management problems based on the Supply-Demand equilibrium. Our test results and generic analysis show that the proposed management method can improve the team work efficiency significantly. For most cases, it can improve the production efficiency by 40%!