The replacement of an existing product with a new one presents many challenges. In particular, uncertainties in a new product introduction often lead to extreme cases of demand and supply mismatches. This paper addresses inventory planning decisions for product upgrades when there is no replenishment opportunity during the transition period. We allow product substitution: when a company runs ou...

We assume that product i has a constant hazard of adjusting, fi, in each month, where fi ∼ Beta(a, b). Let us denote the product’s lifetime by ni. These assumptions imply that the total number of price changes in a product’s lifetime is distributed according to the binomial distribution, xi ∼ Bin(ni, fi). We assume, furthermore, that fi is distributed according to the beta distribution, fi ∼ Be...

Cache memories help bridge the cycle-time gap between fast microprocessors and relatively slow main memories. By holding recently referenced regions of memory, caches can reduce the number of cycles the processor must stall while waiting for data. As the disparity between processor and main memory cycle times increases by 40 percent or more per year cache performance becomes ever more critical....

In this paper the impact of product market uncertainty on the optimal replacement timing of a production facility is studied. The existing production facility can be replaced by a technologically more advanced and thus more cost-effective one. We take into account strategic interactions among the firms competing in the product market by analyzing the problem in a duopolistic setting. We calcula...

Tryptophanase from Bacillus alvei exhibited the expected spectrum of pyridoxal-5'-phosphate-dependent reactions. It exhibited l-serine dehydratase, S-alkyl-cysteine lyase, and cysteine desulfhydrase activities, as well as the classic tryptophanase reactions (all beta elimination reactions). It also acted as a tryptophan synthetase (beta replacement reactions) using indole plus l-serine or l-cys...

The aim of this work was to study the effect of sodium chloride replacement with potassium chloride on quality changes of hot smoked Kilka during storage at ± 4°C. To achieve this, after initial preparation, samples were exposed to brining process in two salts. This study was designed in two stages: in the first stage, different levels of salt replacement were used to select the best...

Background The global prevalence of diseases transmitted by Aedes aegypti mosquitoes, such as dengue, Zika and Yellow Fever, is increasing, but development promising new mosquito control technologies could reverse this trend. Target Product Profiles (TPPs) Preferred Characteristics (PPCs) documents issued the World Health O...

The problem of document replacement in web caches has received much attention in recent research, and it has been shown that the eviction rule “replace the least recently used document” performs poorly in web caches. Instead, it has been shown that using a combination of several criteria, such as the recentness and frequency of use, the size, and the cost of fetching a document, leads to a size...

With an ever increasing amount of data to store, hierarchical storage management (HSM) systems must still use tape for tertiary storage. A disk cache is used to reduce the access time to data stored on tapes in a robot device. Due to the sequential access to tape devices, some HSM systems will transfer whole files between disk cache and tape. In this case the disk cache is forced to handle stor...