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A reasonable strategy is the key to control stocks in the random inventory system. Yet it is difficulty to design such strategy by analytical method because of the randomness of variables and complex and nonlinear relationship among them. This paper provides a random inventory model with no filling the missing. The model generates the random variables subjected to the distribution of requirement and arrival delay firstly based on Monte Carlo theory, and then utilizes the strategy of (s, S) to change the lower and upper order points, and takes the ordering point and ordering quantities as input variables, the total inventory costs as output variables. By simulation with computer and exhaustive method, it seeks the global optimal strategy. Simulation method presented in the paper avoids the affects of the randomness of variables, which is an effective method to solve random system problems.

PAD Class is carried out in the form of teacher's presentation and students' discussions, but the way to evaluate its teaching quality is the same as lecturing class currently. To address this problem, the paper provides a 2-level fuzzy comprehensive evaluation model for PAD Class specially. It takes teaching content, teaching organization, teaching literacy and teaching result as 1-level indexes, and 17 2-level indexes such as necessity, time allotment etc. It quantifies some unclear indexes to values by membership functions and then gets a qualitative conclusion according to the value. In this model the evaluation indexes focus on the teacher's ability to make discuss efficiently, and it lets fuzzy factors more accurate by quantifying. Through practical applications, the teachers' recognition of the evaluation conclusions reaches 93.3%, which is 13.3% higher than that in previous evaluation way.

In this paper, according to the randomness of students ’ arrival in the canteen and the randomness of dining time, a queuing model of canteen service is established. The students ’ arrival rate and service time are randomly simulated, and the students ’ multi-queue dining service is dynamically simulated. So got the queuing time, busy rate of dining windows and other factors. Considering the waiting cost of students and the operating cost of canteen, and effectively combining the epidemic prevention, the optimal number of canteen windows is obtained. It puts forward the optimization scheme for students to eat, and provides feasible suggestions for canteen managers and schools.

With the popularization of computer application, there is a craze for computer certification in the society. Faced with a wide variety of examinations, how to choose a suitable examination is the concern of every examinee. This paper analyzes the current popular examinations from the aspects of examination organization departments, suitable people, examination methods and examination contents. It also puts forward some suggestions on the reform of computer examination.