طراحی سیستم های اطلاعات مدیریت با در نظر گرفتن متغیرهای تصادفی

A management information system (MIS) is one of the important systems to control materials and information harmoniously. The previous design approaches dealt with it qualitatively. Therefore, it was impossible to smooth the office works in the management system. In this paper, we design the MIS using a stochastic Petri net (SPN). First, we describe a typical MIS and explain the concept of SPN. Next, we construct the MIS as the SPN model and obtain the total expected sojourn time of documents in each section. Finally, we propose the design for the MIS with consideration for the smoothing of the office works.

A management information system (MIS) is one of the important systems to control materials and information harmoniously. The MIS is now expressed by the following keywords: (1) network, (2) open system, (3) down sizing, (4) multi-vendor and, that is to say by the other words, as “4F and 1R”, (1) Fast, (2) Flexible, (3) Flat, (4) Fusion, (5) Real. Today, most people say that the data should be processed at the place where the data occurs, and should be returned and fed back quickly with real time. In addition, network and database are required in order to utilize the huge volume of data effectively. Such an information system should not be constituted by the style of a conventional batch system, but by the form of an integrated or total system. Now, we shall imagine a small-scale retail store, e.g., a fruit store, a vegetable store, a drag store, and a fresh fish store, etc. In such stores, originally the master would be a system like the random and real-time access information processing. On the other hand the master deals with sales commodities, schedules of purchasing plan and checks the amount of stock, and so on. Then, he could get all the required information only by his own activities, and therefore would be able to make accurate decisions. The master becomes equivalent to the integrated management system or the total management system itself. As we know from the case above, when we do not use a computer in conventional business, it is quite natural to deal with and control the management and/or the production information by the form of an integrated or total system. In this way, as long as the size of the business is small, the manager can control management organization or function intuitively and easily. However, after the computers and electronic data processing system (EDPS) became the standard tools in business, according to the progress of factory automation and office automation, the management organization became separated and specialized. Furthermore, the data processing interval becomes long, and the unprocessed management information increases in accordance with the increase of the computer’s processing capacity. Consequently, the remarkable delay of the feedback information which is required for managers or foremen would also occur. Recently, a data and function oriented approach (DFOA) has been proposed as a concept of a design for the MIS 1 and 2. This approach enables the designers to easily design and understand the huge MIS without expert knowledge for the management. The style of the analysis and design has been proceeded from the static point of view. That is, it was not a quantitative, but a qualitative method. Hence, it was impossible to smooth the office work load in the system. In this paper, we investigate the MIS using a stochastic Petri net (SPN). The SPN is recognized as a modeling tool for analyzing the performance of discrete-event systems with stochastic variability. It enables one to find the existence of imbalances in such a system, and to improve on those points. In Section 2, we consider a typical MIS which consists of four sections in a model company. Furthermore, the MIS is expressed by an office flowchart. In Section 3, we explain the concept of the Petri nets. The SPN is introduced as a kind of Petri net where each transition is associated with an exponentially distributed random variable which expresses the delay from the enabling to the firing of the transition. In Section 4, we model the typical MIS as the SPN. In Section 5, the expected sojourn time of documents in each place is obtained by simulation. Moreover, we reconstruct the framework of the sections of the MIS, and propose the design for the MIS with consideration for the smoothing of the office works.

In this paper, we investigate the MIS using the SPN model with consideration for the stochastic variability such as the operational time and the interarrival time of the demand. Numerical results show the total expected sojourn time of the documents in each section of the MIS, so that this approach makes it possible to find the existence of unbalanced office work load. Furthermore, we can reconstruct the system by controlling the operational times in each section of the MIS. As a result, it is possible to design the MIS with the smoothing of the office works.