What is dichotomy classification?

What is binary classification? Dichotomy: Divide a group of plants with different characteristics into two parts, and then compare and arrange them step by step for classification, which is called ~. According to ~, it can naturally be called Lamarckian dichotomy.

Bifurcation classification: a group of plants with different characteristics are divided into two parts, arranged step by step and classified, which is called ~. According to ~, it can naturally be called Lamarckian dichotomy. Bifurcation classification is a scientific classification. It divides things into two opposite branches according to one or several characteristics of a group of things, and then divides each branch at the next higher level into two corresponding branches according to another one or several characteristics, and goes on in turn until it is assigned to a specific thing.

Dichotomy classification: a group of plants with different characteristics are divided into two parts, arranged step by step and classified, called ~. According to ~, natural plants can be listed as a classification key table, also known as Lamarckian dichotomy classification.

Why use dichotomy classification? What are the advantages of this classification? Divide a group of plants with different characteristics into two parts, compare and arrange them step by step and classify them, which is called dichotomy.

According to dichotomy, plants in nature can be classified into a key table.

The key to plant classification is the tool to identify plants. The key table is compiled according to the dichotomy classification principle of Frenchman Lamarck. The original flora is divided into two corresponding branches according to obvious and related morphological characteristics, and then the taxon in each branch is divided into two corresponding branches according to relative characteristics, and so on until all taxons are separated. For the convenience of use, each branch is preceded by a certain serial number in the order in which it appears. The number and position (distance from the left) in front of the corresponding two branches should be the same, and the corresponding two branches should retreat one space to the right of the branch at the next higher level, and so on until the end point to be compiled. At the end of each branch is the name of a taxon. This kind of key table is called equidistant key table, which is widely used in all kinds of plant classification. In addition, there are parallel retrieval tables.

The most common search tables are families, genera and species, and families, genera and species of plants can be searched separately. When identifying plants, a key table can be used as needed. Of course, when searching for plants, we should first compare the morphological characteristics of the two branches in the search table with the plant, select the branch that is consistent or basically consistent with the plant, and continue searching in the two branches below the branch until the family name, generic name and species name (including middle name and Latin scientific name) of the plant are retrieved. Then compare the description and legend of the plant with the flora and other documents, or check with the correctly identified specimens in the herbarium to verify whether there are any errors in the retrieval process, and finally identify the correct name of the plant.

Binary classification is also widely used in other scientific fields. Such as the genetic genealogy classification key table. There are often only male patients in the genetic pedigree; Or if a woman is ill, her father must be a patient. According to the principle of binary classification, a brief fixed-distance inheritance is compiled by comparison ... By comparing the characteristics of the above-mentioned genetic disease families with the principle of binary classification, we can master the similarities and differences between them.

What is ABC classification? What is CVA classification? How are they classified? Abc classification is also called Pareto analysis or barreto analysis, Plato analysis, primary and secondary factor analysis, ABC analysis, classified management, key management, ABC management, Barrett analysis, and we usually call it the "80 to 20" rule. It is an analytical method to classify and queue things according to their main technical or economic characteristics, to distinguish between key and general, and to determine different management modes. Because it divides the objects of analysis into three categories: A, B and C, it is also called ABC analysis.

Inventory management method-CVA classification

The CVA management method (key factor analysis) is mainly due to the fact that the C-class goods in ABC classification have not been paid enough attention, which often leads to the suspension of production. Therefore, CVA management method is introduced to supplement ABC classification, and the goods are divided into four grades: the highest priority, the higher priority, the medium priority and the lower priority, and the shortage degree of materials in different grades is different.

Dichotomy classifies books into textbooks-main courses

-Minor courses

-reading after class, it is best not to read too many books, you will be tired!

What is ABC classification? The full name of ABC classification should be ABC classification inventory control method. Also known as Pareto analysis or barreto analysis, Plato analysis, primary and secondary factor analysis, abc analysis, classified management, material key management, ABC management, Barrett analysis, we also call it the "80 to 20" rule. EMBA, MBA and other mainstream business education have introduced the enlightenment of ABC classification to enterprise management and its influence on managers' organizational decision-making.

Should use economics, business management

brief introduction

ABC classification was initiated by Italian economist vilfredo pareto. ABC analysis is a common analytical method in warehouse management, and it is also a basic work and cognitive method in economic work. The application of ABC analysis in warehouse management can easily achieve the following effects: first, it reduces the total inventory; Second, liberated the occupied funds; Third, straighten out the inventory structure; Fourth, save management power. 1879 when Pareto studied personal income distribution, he found that the income of a few people accounted for most of all people's income, while the income of most people only accounted for a small part. He showed this relationship with a chart, which is the famous pareto chart. The core idea of this analysis method is to distinguish primary and secondary factors among many factors that determine a thing, and find out a few key factors that play a decisive role in it and most secondary factors that have little influence on it. Later, Pareto method was continuously applied to all aspects of management. 195 1 year, which was applied to inventory management by management scientist H.F.Dickie and named ABC method. From 195 1 year to 1956, Joseph Zhu Lan introduced ABC method into quality management to analyze quality problems, which was called pareto chart. 1963 Peter ·P·f· Drucker extended this method to all social phenomena, making activity-based costing a widely used management method for enterprises to improve efficiency.

This rule identifies some controversial issues by ranking similar issues or projects. Through long-term observation, Pareto found that 80% people in the United States only have 20% property, while the other 20% people own 80% property in the country. Many things conform to this law. So he applied this law to production. His main point is that you will get better results if you allocate time and strength to a small part of the total. Of course, it is also dangerous to ignore class B and class C. In Pareto rules, class B and class C get much less attention than class A..

ABC classification, also known as Pareto analysis, also known as primary and secondary factor analysis, is a commonly used method in project management. It is an analytical method to classify and queue things according to their main technical or economic characteristics, to distinguish between key and general, and to determine different management modes. Because it divides the objects of analysis into three categories: A, B and C, it is also called ABC analysis.

In the analysis diagram of ABC method, there are two vertical coordinates, one horizontal coordinate, several rectangles and a curve. The left ordinate represents the frequency, and the right ordinate represents the frequency as a percentage. The abscissa represents the factors that affect the quality, which are arranged from left to right according to the size of influence, and the curve represents the cumulative percentage of influencing factors. Generally speaking, the cumulative percentage of the curve is divided into three grades, and the corresponding factors are divided into three categories:

Class A factor is the main influencing factor, and its cumulative percentage is 0%~80%.

Class B factors, with cumulative frequency of 80%~90%, are secondary influencing factors.

Class C factors are general influencing factors, and the cumulative frequency is 90%~ 100%.

Application and interpretation

ABC classification is a method to classify and arrange things according to their main technical and economic characteristics, so as to realize different treatment and management. ABC method is a law derived from Pareto law 80/20. The difference is that the 80/20 law emphasizes grasping the key, while the ABC law emphasizes distinguishing priorities and divides the management objects into three categories: A, B and C.

195 1 year, management scientist dyke first applied ABC rules to inventory management. From 195 1 to 1956, Zhu Lan applied ABC to quality management and creatively formed another management method-Pareto diagram method. In 1963, Drucker extended this method to a wider range of fields.

1.ABC rules and efficiency

In the face of complex and messy processing objects, if you can't distinguish between primary and secondary, you can imagine that its efficiency and benefit can't be high. However, it is sure to get twice the result with half the effort by prioritizing and grasping the main targets. For example, in inventory management, applying this rule can greatly improve work efficiency and benefit.

In a large company, there are usually many kinds of inventory, which may be hundreds of thousands or even hundreds of thousands. Trivial management makes managers too tired to keep, but it has little effect, and there may be confusion, which will cause great losses:

First, it is difficult to make an inventory, and it is difficult to ensure accuracy. For unimportant materials, such as low-value consumables, the impact may not be great, but for important materials, such as key parts of products, if the inventory is wrong, it may lead to material shortage, production will inevitably be affected, thus failing to meet market demand, losing market opportunities and losing customers.

Second, it is difficult to control the stock. The inventory of important materials should be monitored as a key point to ensure that there is no shortage of materials. Non-important materials can be stocked according to a certain estimated amount because of their low importance and small capital occupation. If we carry out a management, we may pay attention to a large number of unimportant materials and ignore the control of important materials.

There is a saying that "picking up sesame seeds and losing watermelon", which means that people who can't apply ABC rules are also remarkable in our daily affairs. Faced with many problems, if we classify ABC and then deal with the main problems, the minor and unimportant problems will often be solved.

2. How is 2.ABC classified?

The processing objects we face can be divided into two categories, one is quantifiable and the other is unmeasurable.

For those that cannot be quantified, we can usually only judge by experience. For those that can be quantified, classification is much easier and more scientific. We take inventory management as an example to illustrate how to classify.

The first step is to calculate the amount of each material.

The second step is to sort the amount from large to small to form a table.

The third step is to calculate the proportion of each material amount to the total inventory amount.

The fourth step is to calculate the cumulative proportion.

The fifth step is classification. The most important class A materials are those with a cumulative ratio between 0% and 60%. The cumulative proportion is between 60% and 85%, which is the second most important class B material. The cumulative proportion is between 85% and 100%, which is an unimportant class C substance.

PS: According to Building Engineering Management and Practice, Edition 20 16, P3 19 Case 1A420 162, the most important Class A materials are those with a cumulative price comparison between 0% and 75%; The cumulative proportion is between 75% and 95%, which is the second most important class B material. The cumulative proportion is between 95% and 100%, which is an unimportant class C substance. Please pay attention!

Usually, we use ABC analysis table to perform the above steps. As can be seen from the table 1, A, B, C, D and E are Class A, F, G, H, I, J, K, L, M, N and 0 are Class B, and P, O and R are Class C. ..

For different objects, the indicators used in classification are different. The above inventory management adopts inventory value index. For customer management, you can use the customer's purchase amount or gross profit contribution as an indicator. For investment management, the return on investment can be used as an indicator.

Apply for opportunities:

This tool is often used for inventory management. In fact, like the 80/20 rule, it is a ubiquitous management tool, which may be used in all affairs of enterprises.

Application paradigm

Sisco (Sysco, the largest food service sales company in North America)

In the ranking of the world's top 500 enterprises published in 2004, Cisco ranked 179.

ABC method is more widely used in warehousing and logistics management. ABC method is widely used in Shaogang, which is mainly engaged in wholesale business.

Basic procedure

Conduct an analysis

The theoretical basis of 1 ABC analysis Anything complicated in society has a law of "key minority, general majority". The more complicated things are, the more obvious this rule is. If the limited power is mainly (mainly) used to solve a few decisive things, and the limited power is evenly distributed in all things. Comparing the two, of course, the former can achieve better results, while the latter is less effective. Under the guidance of this idea, ABC analysis method finds out the "key minority" through analysis, and determines the appropriate management methods to form a class A object for key management. This can achieve 7-8 times the effect of "getting twice the result with half the effort".

General steps of 2.2. ABC analysis Here only take ABC analysis and key management methods of inventory as examples. Generally speaking, the inventory of an enterprise reflects the level of the enterprise. Through the investigation of enterprise inventory, we can get a general understanding of the operating conditions of enterprises. Although ABC analysis has formed a basic management method in enterprises and has wide applicability, it is still widely used in inventory analysis.

The general steps of ABC analysis include: collecting data, processing data, making ABC analysis table, determining classification according to ABC analysis table, and drawing ABC analysis chart.

Implementation countermeasures

This is the process of classified management. According to the results of ABC classification, the management intensity and economic effect are weighed, and the ABC classification management standard table is formulated to manage the three types of objects differently.

Specific steps

collect material

Collect relevant data according to the analysis object and content. For example, if you plan to analyze the product cost, you should collect the information of product cost factors and product cost composition; If you plan to analyze a system and engage in value engineering, you should collect information such as regional functions and regional costs in the system. If we want to analyze the railway safety, we must collect the factors that affect the railway safety and the information about the quality of railway related personnel.

process data

Sort out the collected data, and calculate and summarize as needed.

Making ABC analysis table

The columns of ABC analysis table are as follows: the first column is the name of the article; The second column is the cumulative number of items, that is, each item is the number of items, and the cumulative number of items is actually the serial number; The cumulative percentage of the items in the third column, that is, the cumulative percentage of the total items; Unit price of the fourth column project; Average inventory in the fifth column; The sixth column is the unit price of the fourth column multiplied by the average inventory of the fifth column, which is the average capital occupation of various items; The seventh column is the accumulation of average capital occupation; Cumulative percentage of average capital occupation in the eighth column; The ninth column is the classification result. The tabulation is made according to the following steps: Fill the average capital occupation calculated in step 2 in the sixth column of the table from high to low. Subject to this column, fill in the name of equivalent goods in the first column, fill in the unit price of goods in the fourth column, and fill in the average inventory in the fifth column, numbered 1, 2,3,4 ... In the second column, the items will be accumulated. After that, calculate the cumulative percentage of the project and fill it in the third column; Calculate the cumulative average capital occupation and fill in the seventh column; Calculate the cumulative percentage of average capital occupation and fill in the eighth column.

Determine classification

According to the ABC analysis table, observe the cumulative percentage of projects in the third column and the cumulative percentage of average capital occupation in the eighth column, and determine the first few items with the cumulative percentage of projects of 5- 10% and the cumulative percentage of average capital occupation of 70-75% as Class A; Projects with cumulative projects accounting for 20-25% and average capital occupation accounting for 20-25% are clearly classified as Class B; The cumulative percentage of Class C projects is 60-70%, while the average cumulative percentage of capital occupation is only 5- 10%.

Draw ABC analysis diagram

Taking the cumulative project percentage as the abscissa and the cumulative capital occupation percentage as the ordinate, according to the data provided by the third and eighth columns of ABC analysis table, take points on the coordinate map, connect the curves of each point, and draw ABC curve.

According to the data corresponding to ABC analysis curve and ABC analysis table, three categories, A, B and C, are determined, and the ABC analysis diagram is made by marking the three categories on the diagram. In management, if the ABC analysis chart is still not intuitive, it can also be drawn as a histogram as shown in the figure.

Case analysis editor

People take inventory management as an example to illustrate the specific application of ABC method. If people intend to analyze the annual sales volume of inventory goods, then: first, collect the annual sales volume and unit price of each commodity.

Secondly, the original data are sorted out and calculated as required, such as sales, projects, cumulative projects, cumulative project percentage, cumulative sales, cumulative sales percentage and so on.

Third, make ABC classification table. When the total number of projects is not too large, you can list all the projects one by one by using the method of large queue. According to the size of sales, all goods are arranged in order from high to low; Fill in the necessary original data and statistical summary data, such as sales volume, sales volume, sales percentage, etc. Calculate the cumulative number of projects, cumulative percentage of projects, cumulative sales and cumulative sales percentage; The first items of 60 ~ 80% of cumulative sales are classified as Class A; Some projects with sales of about 20 ~ 30% are classified as Class B; Set the rest of the projects as Class C. If there are too many projects, it is impossible to arrange them all in the table or it is not necessary to arrange them all, you can adopt a hierarchical method, that is, first stratify according to the sales volume to reduce the number of projects in the project column, and then list the key Class A projects one by one according to the hierarchical results for key management.

Fourthly, according to the relevant information in the ABC analysis table, the ABC analysis chart is drawn with the cumulative project percentage as the abscissa and the cumulative sales percentage as the ordinate.

Fifth, according to the results of ABC analysis, different management strategies are adopted for ABC's three types of goods.

ABC classification can also be applied to all aspects of quality management, cost management and marketing management.

In quality management, people can use ABC analysis to analyze the main factors affecting product quality and take corresponding countermeasures. For example, people list the factors that affect the quality of products, including the quality of purchased parts, the condition of equipment, process design, the change of production plan, the technical level of workers, and the implementation of operating procedures by workers. People use the vertical axis to express the cumulative percentage of unqualified products caused by the first few factors in the total number of unqualified products, and the horizontal axis arranges the factors affecting product quality according to the number of unqualified products from large to small. In this way, people can easily divide the factors that affect product quality into Class A, Class B and Class C. Assuming that the quality of purchased parts and the maintenance condition of equipment are Class A factors that cause product quality problems, people should take corresponding measures to strictly control the procurement process of purchased parts and strengthen equipment maintenance, so as to solve these two problems well and reduce the number of unqualified products by 80%.

ABC analysis can also be applied to marketing management. For example, when analyzing and managing the customers of a product, an enterprise can divide users into Class A users, Class B users and Class C users according to the purchase quantity. Due to the small number of Class A users, the purchase volume accounts for 80% of the company's product sales. Generally, enterprises will set up special files for Class A users, assign special sales personnel to be responsible for the sales business of Class A users, provide sales discounts, send people to visit users regularly and adopt direct sales channels. For a large number of C-type users with small purchases and scattered distribution, we can adopt the channels of using middlemen and indirect sales.

It should be noted that ABC analysis generally divides the analysis objects into three categories: A, B and C.. However, according to the characteristics of the importance distribution of the analysis objects and the size of the number of objects, people can also be divided into two or more categories.

origin

ABC analysis refers to the method of dividing inventory materials into three levels according to their importance: particularly important inventory (Class A materials), generally important inventory (Class B materials) and unimportant inventory (Class C materials), and managing and controlling them according to different types of materials. ABC analysis is the application of Pareto theory in the field of logistics management. /kloc-In the 8th century, Italian economist Willy Fred Pareto found that 20% of people control 80% of wealth, while 80% of people only own 20% of wealth. He showed this relationship with a chart, which is the famous Pareto theorem. The core idea of this analysis is that among many factors that determine a thing, a few factors play a decisive role, and most of them belong to minor factors that have little influence on it. 195 1 year, which was applied to inventory management by management scientist Dyke and named ABC analysis method. Later, Zhu Lan introduced it into quality management for quality analysis, which is called ranking chart. 1963, Drucker, a master of management, extended it to the whole society, making it a widely used management method.

What is taxonomy? Knowledge exists between comparative classifications. Classification is a natural process of human beings, which has been carried out unconsciously. All living things are classified, for example, food is divided into edible and inedible. Children who watch TV can be divided into good people and bad people.

The classification of organisms is called systematics or taxonomy, which should reflect the evolutionary tree between different organisms. Taxonomy divides organisms into different groups, while systematics tries to find the relationship between organisms. The dominant classification system is Linnaeus, which includes a generic name and a specific title. There are many international agreements on the principles of naming organisms, such as the International Nomenclature of Plants (ICBN), the International Nomenclature of Animals (ICZN) and the International Nomenclature of Bacteria (ICNB). The fourth draft of BioCode was published in 1997. It attempts to standardize the naming of three fields, but it has not been formally adopted. The International Rules for the Classification and Naming of Viruses (ICVCN for short) is not a biological naming law.

Traditionally, organisms are divided into five realms, which was put forward by Sahn = 1949:

* boundary monera- protozoa-fungi-plants-animals.

Copland put forward four definitions:

Bacteria (bacteria and cyanobacteria)-protozoa-plants-animals.

Some people also use the three-domain theory. This classification method reflects whether cells have nuclei and the differences between cell membranes and cell walls.

* archaea-eubacteria-eukaryote

It is difficult to distinguish between living things and non-living things, because there are some "parasites" (that is, "viruses") in cells, and they do not show active life forms outside cells.

* virus-viroid-prion

[edit]

see

Plant taxonomy-animal taxonomy

:: Information classification

:: Biological taxonomy

O plant classification

O animal classification

O insect taxonomy

+Termite classification

[edit]

sorted table

:: Summary of biological classification

* archaea classification table

* bacterial classification table

* Plant classification table

* Animal classification table

* Insect classification table

* bird DNA classification system

* Traditional bird classification system

:: Mineral list

[edit]

see

* Bacon

* Instrumentalism

From ":Wikipedia.blog./wiki/%E7% A7% 91%E5% AD% B8% E5% 88% 86% E9% A1%9e"

Category: classification method

Classification is a method to identify things by clustering things that meet the same standard and separating different things according to their properties, characteristics and uses.

Classification refers to the structure of systematizing classes or groups according to their relationships, which is embodied in a system table organized by many categories according to certain principles and relationships, and serves as the basis and tool for classification work. Classification includes cross classification, tree classification and so on.

It is a cost calculation method to simplify the calculation work when there are many varieties and specifications of products, but they can be classified according to certain standards. It is characterized by: collecting production costs according to product categories and calculating the costs of such products; The cost of different varieties (or specifications) of products in a category is determined by a certain method.

Classification is a job evaluation method that defines job categories and grades according to job responsibilities, skills and working conditions.

If the job responsibilities, skills, working conditions and other work elements are the same or similar, these jobs are classified as the same type of work and called a work family. For example, positions such as recruitment supervisor, training supervisor and salary supervisor are all engaged in human resource management because of the same job responsibilities, so these positions are all included in the human resource management family. Although the jobs with the same or similar work difficulty are not in the same working family, they have the same salary, and the salary levels of these jobs are also the same. For example, in some enterprises, employees with engineer qualifications, although not department managers, have the same salary level as managers.