Standardization and certification of information systems development

Information Systems;Development;Standardization;management information systems

Distribution planning for a divergent 2-echelon network without intermediate stocks under service restrictions

In this paper we discuss a distribution planning procedure for a system consisting of one central depot supplying a number of end stockpoints. The central depot is not allowed to hold stock and allocates all incoming goods immediately to these end stockpoints. An ordering and allocation policy is presented which is based on a decomposition method. The emphasis lies on the realization of pre-determined target service levels in the various stockpoints. In this paper we present two adjustment methods which improve the service performance considerably in certain cases. Another important contribution of this paper is the generalization of the concept of imbalance. An analytical approximation of the probability of imbalance is presented. An extensive simulation study validates the analytical results

A trade off between emergency repair and inventory investment

In this paper we present an emergency repair model. We model a situation where failed parts arrive at a repair shop according to a Poisson process. If the stock on hand of serviceable spare parts exceeds a given emergency trigger level, the failed part is sent into normal repair. Otherwise the failed part is sent into an alternative emergency repair channel. Upon arrival failed parts are exchanged for serviceable spare parts, if available. Otherwise the demand is backordered. A backorder is filled with the first part that becomes available from either one of the repair processes. The repair times (including transportation time) are assumed to be exponentially distributed. We analyze the impact of using emergency repair on two service measures: the fraction of demand that is satisfied from stock on hand and the expected duration of a backorder. We calculate the initial stock level and the emergency trigger level that minimize the total cost for a given emergency repair rate. The proposed policy is compared with two other policies: (1) emergency repair is not used and (2) emergency trigger level is zero. We find that significant service improvements and cost reductions can be obtained by using our emergency repair policy. We also present simulation results showing that the distribution of the repair times has a negligible effect on the relevant service measures. Finally, we compare our results with the results of an emergency supply model by Muckstadt and Thomas [1] Again we observe significant cost reductions when using our policy

A trade off between emergency repair and inventory investment

In this paper we investigate the effect of using emergency repair on the service performance of a repair shop. Failed parts arrive at the shop according to a Poisson process. If stock on hand of serviceable spare parts is positive, the failed part is exchanged for a spare part and sent into normal repair. If stock on hand is zero, the failed part is sent into an alternative emergency repair channel. The backorder is filled with the first part that becomes available from either one of the repair processes. Both repair processes are assumed to be exponentially distributed. This paper considers the trade off between using emergency repair and investment in spare parts, such that a predetermined service target for the repair shop is realized. Two service measures are considered, that is, the fraction of demand satisfied from stock on hand and the expected duration of a backorder

Characterisation of the androgen regulation of glycine N-methyltransferase in prostate cancer cells

The development and growth of prostate cancer is dependent on androgens; thus, the identification of androgen-regulated genes in prostate cancer cells is vital for defining the mechanisms of prostate cancer development and progression and developing new markers and targets for prostate cancer treatment. GlycineN-methyltransferase (GNMT) is aS-adenosylmethionine-dependent methyltransferase that has been recently identified as a novel androgen-regulated gene in prostate cancer cells. Although the importance of this protein in prostate cancer progression has been extensively addressed, little is known about the mechanism of its androgen regulation. Here, we show that GNMT expression is stimulated by androgen in androgen receptor (AR) expressing cells and that the stimulation occurs at the mRNA and protein levels. We have identified an androgen response element within the first exon of theGNMTgene and demonstrated that AR binds to this elementin vitroandin vivo. Together, these studies identify GNMT as a direct transcriptional target of the AR. As this is an evolutionarily conserved regulatory element, this highlights androgen regulation as an important feature of GNMT regulation.</jats:p