We consider a firmthat sells seasonal goods. The firm seeks to reach a fixed levelof goodwill at the end of the selling period, with the minimumtotal expenditure in promotional activities. We consider thelinear optimal control problem faced by the firm which can onlycontrol the communication expenditure rate; communication isperformed by means of advertising and sales promotion. Goodwilland sales levels are considered as state variables andword-of-mouth effect and saturation aversion are taken intoaccount. The optimal control problem is addressed by means of theclassical Pontryagin Maximum Principle and the solution can beeasily found solving, in some cases numerically, a system of twonon linear equations. Moreover, a parametric analysis is performedto understand how the total expenditure in communication shouldbe divided between advertising and sales promotion.

Long running software systems are known to experience an aging phenomenon called software aging, one in which the accumulation of errors during the execution of software leads to performance degradation and eventually results in failure. To counteract thisphenomenon a proactive fault management approach, called software rejuvenation, is particularly useful. It essentially involves gracefully terminating an application or a system and restarting it in a clean internal state. In this paper, we reconsider the non-homogeneousMarkovian models for a single-server type of software system with rejuvenation in Garg et al. (1998), and revisit them from the theoretical view point. More precisely, it is assumed in these models that software failures can occur with positive probability during idle periods in transaction systems, but we exclude this unreasonable situation in our refined models.

In this paper, open shop scheduling problems with limited machine availabilityare studied. Such a limited availability of machines may appear inmany real-life situations, e.g. as preventive maintenance activities.Three types of jobs are distinguished: non-preemptable,resumable and preemptable. An operation of a resumable job if not completedbefore a non-availability period of a machine may be suspended and continuedwithout additional cost when the machine becomes available.In the paper, results are given for the scheduling problems associated withthe three types of jobs.Forpreemptable jobs polynomial-time algorithms based on the two-phase methodare proposed.

The present study proposes a theoretical model to test sales velocity for new products introduced in small format retail stores. The model is designed to distinguish fast moving products within a relatively short period. Under the proposed model, the sales of a newly introduced product are monitored for a prespecified period T, e.g., one week, and if the number of items sold over T is equal to a prespecified integer k or more, the product is considered a fast moving product and is carried over to the following sales periods. A slow moving product could be quickly replaced with alternative merchandise in order to make best use of shelf space. The paper first presents definitions of fast and slow moving products, and then a proposed sales test policy based on the model is formulated, where the expected loss is to be minimized with respect to the integer k. Numerical examples based on actual data collected from a convenience store in Japan are also presented to illustrate the theoretical underpinnings of the proposed sales test model.

A problem (arisen from applications to networks) is posed about the principal minors of the matrix of transition probabilities of a Markov chain.