Value Iteration for Perishable Inventory Control

This thesis focuses on finding optimal order policies for perishable inventory in supermarkets. By means of value iteration (VI) and simulation, several inventory dynamics are compared. First, several cases were designed: three cases without taking perishability into account, and one case based on perishability. Case 1-3 have the following characteristics, respectively: 1) backlogging is possible, and costs should be minimized; 2) backlogging is not permitted, and profit should be maximized; 3) the customer service level (CSL) should be met, and costs should be minimized. The fourth case, 4) contains products which perish after one day, and the profit should be maximized. The calculation of an optimal order policy is performed by implementing a VI method. The optimal order quantity per inventory level calculated in VI, is used in the simulation. The four cases gave different optimal order-policies. The first three cases showed a lot of similarities, and had the characteristics of an (s; S)-policy. Case 4, containing perishable products, was highly influenced by the fixed order cost k. If the fixed order costs were low, an optimal order policy could be determined. This was not possible for high fixed order costs, the order moments and order quantities turned out to be periodic. For fixed costs which were too high, no orders were placed. The order policy for the low fixed costs did not match the policies in the inventory control chapter. In case 4, we had to deal with the curse of dimensionality. The limited shelf-life causes an increase in state space. To deal with this problem, we had to keep the elements per set of states low

On computational procedures for Value Iteration in inventory control

Dynamic programming (DP) is often seen in inventory control to lead to optimal ordering policies. When considering stationary demand, Value Iteration (VI) may be used to derive the best policy. In this paper, our focus is on the computational procedures to implement VI. Practical implementation requires bounding carefully the state space and demand in an adequate way. We illustrate with small cases the challenge of the implementation. We also show that handling service level constraints is not straightforward from a DP point of view. Moreover, when taking the age distribution into account for perishable products, the curse of dimensionality provides an additional challenge.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto nacional RTI2018-09599

Changes in behavioural synchrony during dog-assisted therapy for children with autism spectrum disorder and children with Down syndrome

BACKGROUND: Dog-assisted therapy (DAT) is hypothesized to help children with autism spectrum disorder (ASD) and Down syndrome (DS). METHODS: The present authors compared synchronous movement patterns of these children (n = 10) and their therapy dogs during the first and last session of a DAT programme, and their post-therapy changes in emotional and behavioural problems. RESULTS: The present authors found a significant increase in synchrony between child and therapy dog over time. Exploratory analyses suggest more synchrony between children with ASD and their therapy dogs, compared to the children with DS. CONCLUSIONS: This study is the first to test the synchrony hypothesis, shedding light upon a mechanism that may underlie the effect of DAT and how this may be different for children with ASD and DS

Prevalence of congenital heart defects and persistent pulmonary hypertension of the neonate with Down syndrome

The aim of this study was to assess the prevalence of congenital heart defects (CHDs) and persistent pulmonary hypertension of the neonate (PPHN) in children with Down syndrome (DS) and to assess its impact on neonatal factors. It was a prospective study of a birth cohort of children with DS born between 2003 and 2006 registered by the Dutch Paediatric Surveillance Unit (DPSU). A CHD occurred in 43% of 482 children with trisomy 21. Atrioventricular septal defect was found in 54%, ventricular septal defect in 33.3% and patent ductus arteriosus in 5.8%. The incidence of PPHN in DS was 5.2%, which is significantly higher than the general population (p < 0.001). The reported mortality in newborns with DS was overall 3.3% and was still significant higher in children with a CHD versus no CHD (5.8% versus 1.5%) (p = 0.008). The presence of CHD in children with DS had no influence on their birth weight, mean gestational age and Apgar score. In neonates with DS, we found not only a 43% prevalence of CHD, but also a high incidence of PPHN at 5.2%. Early recognition of the cardiac condition of neonates with DS seems justified

Downregulation of Homologous Recombination DNA Repair Genes by HDAC Inhibition in Prostate Cancer Is Mediated through the E2F1 Transcription Factor

Histone deacetylase inhibitors (HDACis) re-express silenced tumor suppressor genes and are currently undergoing clinical trials. Although HDACis have been known to induce gene expression, an equal number of genes are downregulated upon HDAC inhibition. The mechanism behind this downregulation remains unclear. Here we provide evidence that several DNA repair genes are downregulated by HDAC inhibition and provide a mechanism involving the E2F1 transcription factor in the process.Applying Analysis of Functional Annotation (AFA) on microarray data of prostate cancer cells treated with HDACis, we found a number of genes of the DNA damage response and repair pathways are downregulated by HDACis. AFA revealed enrichment of homologous recombination (HR) DNA repair genes of the BRCA1 pathway, as well as genes regulated by the E2F1 transcription factor. Prostate cancer cells demonstrated a decreased DNA repair capacity and an increased sensitization to chemical- and radio-DNA damaging agents upon HDAC inhibition. Recruitment of key HR repair proteins to the site of DNA damage, as well as HR repair capacity was compromised upon HDACi treatment. Based on our AFA data, we hypothesized that the E2F transcription factors may play a role in the downregulation of key repair genes upon HDAC inhibition in prostate cancer cells. ChIP analysis and luciferase assays reveal that the downregulation of key repair genes is mediated through decreased recruitment of the E2F1 transcription factor and not through active repression by repressive E2Fs.Our study indicates that several genes in the DNA repair pathway are affected upon HDAC inhibition. Downregulation of the repair genes is on account of a decrease in amount and promoter recruitment of the E2F1 transcription factor. Since HDAC inhibition affects several pathways that could potentially have an impact on DNA repair, compromised DNA repair upon HDAC inhibition could also be attributed to several other pathways besides the ones investigated in this study. However, our study does provide insights into the mechanism that governs downregulation of HR DNA repair genes upon HDAC inhibition, which can lead to rationale usage of HDACis in the clinics

The DUT racing team; design, produce and race your own car

The DUT Racing Team consists of a group of sixty students that will design and produce a racing car for the Formula Student competition in the period of one academic year. Within the team there is a great variety of people, all from different faculties, nationalities and age. In addition there is an association of former members that ensures the continuity of the project. This make the DUT Racing Team the largest and oldest student project at the TU delftAerospace Engineerin

The refittable ship: A method for modular design of a ship's power supply

Traditionally, ships are powered by fossil fuels in combustion engines, causing 3% of global greenhouse gas emissions. Alternative installations have yet to prove their reliability and are currently not as cheap or technological ready. To enable ship-owners to prepare their ship for the future, but postpone their decision on which alternative installation to choose, it is the objective of this research to develop and validate a method for modular design of the power supply system of a ship, that allows a low-impact refit to lower the ship’s greenhouse gas emissions when the alternative power supply technology is ready.This method is developed within the scope of short-sea dry cargo vessels with little auxiliary power(&lt;20%) that is to be refitted before 2050, but the method is kept as general as possible. The studied background information includes greenhouse gases, possible alternative installations, low-impact refits, and modularity. Furthermore, the method is verified and validated using two different case ships. In this report information about the method for modular design can be found, but also information on alternative power supply systems. The method is presented in chapter 5 and 6. It is concluded in chapter 7 that the developed method is effective and enables a low-impact refit, without significant negative impact on the initial design.It is concluded from this research that the method is effective and enables a low impact refit, without significant negative impact on the original design.For readers who want to know more about the alternative installations instead of the method, some basic information about available energy carriers and power supply units can be found in 2.3, the components of alternative installations of the case ship can be found in chapter 4 and the effect of those installations on the design to be found in section 5.3.Marine Technology | Marine Engineerin

De magistrat de liaison

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