1. index adjustment, two-level dynamic adjustment of material price and traditional cost expression are approximate methods adopted in the case of insufficient computing power and high information acquisition cost.
The preparation process of budget (final accounts) fully embodies the thinking method of analyzing first and then synthesizing, as shown in the figure, the composition of the total construction cost in the project budget (final accounts):
Expressed as:
P total cost =∑N engineering quantity I= 1 () The content of semi-finished products can be incorporated into the quota of people, materials and machines, which can be simplified as:
That is, the total construction cost of each building consists of component cost and comprehensive cost, and each component cost consists of the sum of the price of its component materials, the cost of labor and machinery shifts required for production, the management fee and tax of the component or its component materials. Usually, an ordinary project contains about 200 components, that is, quota projects, with about 1 000 kinds of materials. If calculated manually according to the above formula, the calculation amount is extremely large.
In actual manual operation, the direct cost within the quota is often obtained by directly multiplying the labor cost, material cost and machinery cost in the quota book by the engineering quantity. In addition, according to the comparison between the material price in the current reporting period and the material price used in the preparation of the quota, the price difference caused by the price change is calculated and added to the direct cost within the quota to obtain the direct cost of the project. Then, according to the direct cost and fixed direct cost of the project, various costs are calculated to form a cost table and get the total cost of the project.
Due to the limitation of calculation tools and means, the above process is often further approximate, which simplifies the calculation process on the premise of ensuring that the pre-calculation (final) results will not have great deviation:
(A) reflected in the calculation of price differences.
Because there are many materials used in a project, the price changes of various materials have different effects on the project cost, so the ones with great influence are called main materials and the ones with little influence are called auxiliary materials. For example, in the pre-calculation of 94 and 98 quotas in Fujian Province, different methods are used to calculate the price fluctuation of main materials and auxiliary materials. The main material shall summarize the price difference of the main material of the whole project according to its content × price difference, and the auxiliary material shall adopt the index method. The fluctuation index of the proportion of auxiliary materials to the fixed direct cost is roughly calculated by each province or city on a regular basis according to typical projects, and the fixed direct cost is directly multiplied by the index to replace the adjustment difference of auxiliary materials in the project. This statistical method will lead to certain errors. Even if the main material adjusts the price difference, it cannot be calculated one by one. Usually, the consumption of major materials with similar prices is aggregated together, and only the price of one material is investigated. The price difference of this material multiplied by the cumulative consumption of similar materials is used as the price difference of these materials and included in the expense table. This algorithm can only be based on the premise that the price fluctuation of similar materials is the same. There are two reasons for adopting this algorithm: 1, and the limited manual calculation ability makes the work efficiency and accuracy become a pair of contradictions. The algorithm can find a suitable balance between work efficiency and accuracy. In the early stage of using computers to prepare pre-calculation (final calculation), because high-performance computers are still expensive, in order to obtain satisfactory performance and follow the original habits, this management method is still adopted; 2. The means of information circulation can only be copied by hand, which is not convenient to collect, and it is not easy to comprehensively investigate the price of materials. Even high-performance computers can't do anything until the means of information collection, processing and distribution are improved.
(2) Reflected in the calculation of expenses.
As can be seen from the above formula, in fact, the cost is divided into two categories, one is the cost allocated to each quota subtitle, and the other is the comprehensive total cost of the project. The expense category of quota subtitle may be different for each quota, and the rate taken is also different. When calculating the cost manually, it is still summarized in the cost table, and several subprojects are divided into different rates for calculation. This calculation method can't reflect the real cost of each sub-project, such as management expenses and profits. At present, in order to facilitate the price comparison, it is required to directly include the expenses in the quota sub-item.
It can be seen that the traditional pre-calculation method is suitable for the calculation conditions and information circulation conditions at that time, which reduces the workload and improves the work efficiency. However, many approximate methods increase the error of the prediction results, the calculation results are not intuitive, the granularity that can be analyzed and adjusted is coarse, and it is difficult to control when the pre-tender estimate needs to be adjusted accurately.
Second, the development of information technology has improved the calculation conditions, increased the speed of information circulation, and promoted the deepening and diversification of the application of computers in the engineering cost management industry.
Since 1990s, the information technology in the world has made unprecedented development. On the one hand, the computing power and storage capacity of hardware are doubling every eighteen months according to Moore's Law, which makes it possible to have high-performance personal computers at low prices. On the other hand, software tools are becoming more and more powerful. The development of database technology and development tools has improved the ability of data storage and processing and the level of software production, and greatly improved the user interface. And because of the progress of database technology in online transaction analysis ONLINE-AP, we can use information technology to collect and accumulate a large number of completed project data, and conduct fine-grained analysis on this basis. In particular, the rapid popularization of the Internet in the world has shocked all industries, greatly improved the man-machine interface and information acquisition means, made the world truly enter the information age, and solved the contradiction that the amount of information in project cost management is too large to be collected, processed and published. In a word, the progress of information technology not only makes it possible to improve the accuracy of pre-calculation and use more abundant, timely and accurate material prices under the premise of maintaining the original work efficiency (at present, all international project bidding adopts full-cost quotation), but also extends to the whole process of project cost management, that is, from the investment estimation of a project feasibility analysis to the budgetary estimate, budget, audit, stage settlement and final settlement, all of which are established by accumulating the information of completed projects. At the same time, information technology is also widely used in engineering management, quota compilation, engineering quantity calculation, index collection and analysis, information network and so on. At present, the application level of cost management in different stages in China is different, and the types and functions of products available in the market also have their own characteristics. Here is a brief introduction.
(a) the project budget (decision) software:
Also known as "pricing software", the function of this software is mainly used to calculate the quota, and it is one of the earliest application software put into development in the field of cost. After years of development, it has become mature, and has been widely promoted and applied, and achieved remarkable benefits. The software runs on DOS platform in the early days, and gradually transits to Windows and WIN32 environment with the popularity of Windows system. The software includes four subsystems: consumption quota management subsystem, budget price management subsystem, pricing management subsystem and charging quota management subsystem. Pricing software has the following characteristics:
Local characteristics of 1. software package
Obviously, the reason is that the quotas in different regions are different, the prices of materials obviously cannot be the same, the charging standards vary widely, and there may be some special rules and regulations caused by the characteristics of regional buildings and materials in different regions in the budget. These factors make it impossible for the same package price software to be applied in all regions, and the software with strong adaptability needs to set more parameters, which is more complicated to use and difficult for users to accept; When the software with weak adaptability encounters different situations, it often needs to be solved by modifying the source program and recompiling it, which is not conducive to maintenance;
2. Use of pricing software
It depends on the price of materials, and the policy adjustment of local cost departments will also cause the modification of software functions, which requires higher after-sales service of software;
3. The functions and characteristics of package pricing software are different for different majors.
At present, the use of package pricing software has been very common in China, and its functions have been extended from single package pricing and budget submission to many aspects. First, it has expanded upward, adding the function of project management, which can process the data of multiple projects and one project at the same time, and runs through the whole process of cost management from estimation, budgetary estimate, budget, stage settlement and final settlement. Second, the function is further refined, and the analysis of calculation results and fine-grained adjustment are strengthened to facilitate the cost adjustment and control of bidders; Third, the change of budget mode, from the two-stage dynamic adjustment calculation method used by traditional manual algorithm to the comprehensive unit price calculation method to meet the needs of international bidding; Fourth, it is connected with the Internet, which provides users with the material price data needed by the budget software, which facilitates the maintenance of the material price data and improves the work efficiency; Fifth, strengthen the function of accumulating completed project data; Wait a minute.
(2) quota management software:
This kind of software mainly uses data technology to assist the cost department to maintain the quota database, and directly generates the required typesetting format when compiling the quota, so as to reduce the workload of compiling the quota, shorten the typesetting time and reduce human errors, which belongs to the category of management information system.
(3) Engineering quantity calculation software:
This kind of software is used to help calculate the engineering quantity from the construction drawing. The software widely used in China generally adopts drawing method, which requires staff to re-enter various components and their sizes in the drawings on the basis of drawing recognition, and then the system automatically calculates the engineering quantity to get the bill of quantities. This method is more accurate in calculating the engineering quantity, but the workload of re-plotting is still very large. Another method is to scan the engineering drawings directly to form raster files, and then extract features after vectorization by software, and identify the component types and their geometric parameters through pattern recognition technology, and then calculate the engineering quantity; Or use the CAD file of construction drawing generated by design institute to carry out pattern recognition in CAD environment. This method needs a lot of research work on the feature representation and modeling of drawings, extracting the feature parameters of various parts and adopting artificial intelligence technology. In order to replace people in the process of reading pictures, this method is a very promising method. However, according to the development process of Chinese character recognition technology, the characteristics of drawings must be deeply analyzed and studied, and there is still a way to go before software can really replace people reading drawings. The third method is to add the attributes of component characteristic parameters directly to the CAD software used in architectural design, define various component objects, and use these objects to design buildings in structural and architectural design, instead of drawing directly with lines. This method makes the design result contain rich components and parameters instead of lines, and all components and parameters can be separated by a parser, thus avoiding the difficulty of pattern recognition, but it is not easy for designers to change their original habits. Therefore, when the application of artificial intelligence in this field is not deep, it is still necessary to fill the deficiency of software in intelligence through interactive process, and drawing software will dominate in a few years.
(4) Steel sampling software:
At present, this kind of software in China generally adopts tabular method, atlas method or a combination of the two. It also requires staff to select different atlas according to drawings and input various parameters, and then the system can calculate the amount and shape of steel bars according to the atlas and parameters. The data used by this kind of software has a certain intersection with the engineering quantity calculation software. At present, many domestic reinforcement softwares have integrated engineering quantity calculation software, and both of them enjoy component parameter data.
(5) Index collection and analysis system:
The system is used to collect the data of completed projects and analyze them from multiple dimensions, and the results will be used for investment estimation and other aspects. The collection of indicators is a long-term dynamic accumulation behavior. Because the standards are not uniform, there is no perfect index collection and analysis system in China at present. Even if there is an index database, it is only formed by suddenly sorting out the engineering data of a certain period of time in the past. We believe that in order to ensure the availability of data, it is necessary to establish relatively stable indicators and a set of stable coding rules. At present, the quota of each region will be re-compiled in a few years, and each compilation has new characteristics. One solution is to establish a set of relatively stable indicators for the changing quotas and compile a mapping table for each set of quotas. In addition, because there are many characteristic parameters of the project, the amount of data that can be extracted from each project is large and the analysis dimension is wide. By using data warehouse and online analysis system to solve this problem, data warehouse can automatically extract index data on the basis of fine-grained division of metadata and provide tools for multi-dimensional analysis of these data.
(six) the project cost information network:
At present, the hottest point of information technology-the application of Internet technology in the field of project cost has given birth to the project cost information network. This technology has the characteristics of wide distribution, strong technical consistency, simple use and colorful forms of expression, which greatly promotes the circulation speed of information and thus promotes the development of social economy. Taking the cost industry as an example, the material price can be collected and published more timely through the information network, and the accumulated completed project data and standards can be used more widely through the information network, thus expanding the scope of resources. At present, the domestic cost industry has gradually set off a wave of building information networks. If the software mentioned above is a factory and the data is a product, then the Internet is a highway and the website is an information distribution center, that is, a market.
At present, there are engineering cost information networks in Shanghai, Wenzhou, Xiamen, Hunan and Guangxi in China, which have their own characteristics due to differences in regional factors, information sources, investment and technical level. The content of information network usually includes price information, index information, cost index, policies, regulations, standards, unit profiles, comprehensive information, announcements and news, engineering construction and bidding. Its implementation is divided into text and standardized data, the former is descriptive information such as documents and regulations, and the latter is classified data such as material prices, index indicators and quotas. The former is generally stored and maintained in the form of web pages, while the latter is generally entered, processed and published through database technology. The information sources of the information network include internal information from the cost management department and external information from other relevant departments. External information such as material price and market information collected by the information officer is manually classified and input into the system; Internal information can support daily work by establishing intranet and corresponding management information system, and the data generated by information system can be automatically and selectively transmitted to information network through the interface between management information system and information network to form information, thus forming an integrated cost information system.
In addition, information technology has also played a great role in office automation and project management. Through these systems, the business and management of the unit are integrated, which improves the internal operation efficiency of the unit and saves management costs.
Third, according to the above description, we can get the framework of the current application of information technology in the cost industry:
It can be seen that there are several parts in the application of information technology in the cost industry at present: using InterNet/Intranet as a network platform for internal, external and internal communication, implementing office automation and management information system, strengthening management and improving office efficiency, using engineering quantity calculation software and steel bar software to calculate engineering quantity and steel bar consumption, using software package to prepare project budget and final accounts, and using data warehouse technology to establish an index collection and analysis system for the accumulation of completed projects; Use the information network to publish and obtain the information of project budget and final accounts preparation and cost management.
In short, with the further research and application of information technology in the cost industry, it will further promote the development of the cost industry.