An integrated approach for requirement selection and scheduling in software release planning

It is essential for product software companies to decide which requirements should be included in the next release and to make an appropriate time plan of the development project. Compared to the extensive research done on requirement selection, very little research has been performed on time scheduling. In this paper, we introduce two integer linear programming models that integrate time scheduling into software release planning. Given the resource and precedence constraints, our first model provides a schedule for developing the requirements such that the project duration is minimized. Our second model combines requirement selection and scheduling, so that it not only maximizes revenues but also simultaneously calculates an on-time-delivery project schedule. Since requirement dependencies are essential for scheduling the development process, we present a more detailed analysis of these dependencies. Furthermore, we present two mechanisms that facilitate dynamic adaptation for over-estimation or under-estimation of revenues or processing time, one of which includes the Scrum methodology. Finally, several simulations based on real-life data are performed. The results of these simulations indicate that requirement dependency can significantly influence the requirement selection and the corresponding project plan. Moreover, the model for combined requirement selection and scheduling outperforms the sequential selection and scheduling approach in terms of efficiency and on-time delivery. \u

Integrated Gate and Bus Assignment at Amsterdam Airport Schiphol

At an airport a series of assignment problems need to be solved before aircraft can arrive and depart and passengers can embark and disembark. A lot of different parties are involved with this, each of which having to plan their own schedule. Two of the assignment problems that the \u27Regie\u27 at Amsterdam Airport Schiphol (AAS) is responsible for, are the gate assignment problem (i.e. where to place which aircraft) and the bus assignment problem (i.e. which bus will transport which passengers to or from the aircraft). Currently these two problems are solved in a sequential fashion, the output of the gate assignment problem is used as input for the bus assignment problem. We look at integrating these two sequential problems into one larger problem that considers both problems at the same time. This creates the possibility of using information regarding the bus assignment problem while solving the gate assignment problem. We developed a column generation algorithm for this problem and have implemented a prototype. To make the algorithm efficient we used a special technique called stabilized column generation and also column deletion. Computational experiments with real-life data from AAS indicate that our algorithm is able to compute a planning for one day at Schiphol in a reasonable time

The XTC Store: An ‘Experiential’ Public Survey

In 2022, Poppi Drug Museum and researchers from Utrecht University evaluated the societal responses to three scenarios of regulated sales of MDMA through a unique public survey: an ‘XTC store’ in the heart of Utrecht. This report describes the results of this research. The public debate about regulating MDMA – the active substance in ecstasy1 – regularly flares up. The Netherlands is the world’s largest producer and exporter of ecstasy, and more than a million Dutch people have ever used ecstasy. The huge illegal market creates numerous social problems, from unsafe use to criminal subversion of society. However, the conversation about regulation is highly polarised, which limits thinking about alternative scenarios. In this context, drug researchers from the Poppi Museum, in collaboration with researchers from Utrecht University, have further developed three scenarios for alternative, legalised sale of MDMA: a pharmacy, a smart shop and a club/party. With the help of creatives from the Utrecht- based ‘Uitvindersgilde’ and in collaboration with Corné van der Stelt, these three points of sale were set up next to each other in a shop in the centre of Utrecht. The store was open to the public between mid-July and late September 2022. The research linked to the XTC store had the following central question: under what conditions do visitors to the XTC store and drug experts find the regulated sale of ecstasy acceptable? The 1529 visitors to the store gave their views on the various sales conditions. In addition, the team organised two focus group discussions with politicians and policymakers, and drug policy expert academics, which were invited to the location. The first important conclusion is that neither the visitors of the XTC store nor the participants in the focus groups understand the ‘legalisation’ or ‘regulation’ of MDMA would mean allowing the sale of MDMA unlimitedly. Both groups are in favour of (strict) sale restrictions. The experts are more conservative; most opted for a fourth scenario: a specialised but unattractive retail outlet. Most visitors to the XTC store - largely people with experience of XTC use themselves - favoured sales by the pharmacy or a smart shop. In conversation, they too often came up with a scenario between these two options, albeit with a slightly lower threshold than the experts chose. Sales at parties and clubs could still count on acceptance by around 60% of the visitors. But for all scenarios, visitors to the XTC store welcomed restrictions on sales. For example, they favoured a minimum age limit, safety guarantees and limiting the maximum doses in pills. Almost everyone was against allowing marketing and advertising. The research had several limitations as a crossover between an ‘ experiential’ public survey and an art installation. Nevertheless, the report provides interesting indications for follow-up research and further policy explorations. The XTC store also proved very effective in creating awareness and nuanced exchange among visitors and facilitating political dialogue: on location and in the media. The conversation in the store moved beyond the polarised debate about whether or not to regulate and went into depth into possible alternative scenarios for dealing with MDMA. Doing so contributes to a deepening of the Dutch drug debate

PPAR-alpha dependent regulation of vanin-1 mediates hepatic lipid metabolism.

Peroxisome proliferator-activated receptor alpha (PPARα) is a key regulator of hepatic fat oxidation that serves as an energy source during starvation. Vanin-1 has been described as a putative PPARα target gene in liver, but its function in hepatic lipid metabolism is unknown. We investigated the regulation of vanin-1, and total vanin activity, by PPARα in mice and humans. Furthermore, the function of vanin-1 in the development of hepatic steatosis in response to starvation was examined in Vnn1 deficient mice, and in rats treated with an inhibitor of vanin activity. Liver microarray analyses reveals that Vnn1 is the most prominently regulated gene after modulation of PPARα activity. In addition, activation of mouse PPARα regulates hepatic- and plasma vanin activity. In humans, consistent with regulation by PPARα, plasma vanin activity increases in all subjects after prolonged fasting, as well as after treatment with the PPARα agonist fenofibrate. In mice, absence of vanin-1 exacerbates the fasting-induced increase in hepatic triglyceride levels. Similarly, inhibition of vanin activity in rats induces accumulation of hepatic triglycerides upon fasting. Microarray analysis reveal that the absence of vanin-1 associates with gene sets involved in liver steatosis, and reduces pathways involved in oxidative stress and inflammation. We show that hepatic vanin-1 is under extremely sensitive regulation by PPARα and that plasma vanin activity could serve as a readout of changes in PPARα activity in human subjects. In addition, our data propose a role for vanin-1 in regulation of hepatic TG levels during fasting

PPAR-alpha dependent regulation of vanin-1 mediates hepatic lipid metabolism.

Peroxisome proliferator-activated receptor alpha (PPARα) is a key regulator of hepatic fat oxidation that serves as an energy source during starvation. Vanin-1 has been described as a putative PPARα target gene in liver, but its function in hepatic lipid metabolism is unknown. We investigated the regulation of vanin-1, and total vanin activity, by PPARα in mice and humans. Furthermore, the function of vanin-1 in the development of hepatic steatosis in response to starvation was examined in Vnn1 deficient mice, and in rats treated with an inhibitor of vanin activity. Liver microarray analyses reveals that Vnn1 is the most prominently regulated gene after modulation of PPARα activity. In addition, activation of mouse PPARα regulates hepatic- and plasma vanin activity. In humans, consistent with regulation by PPARα, plasma vanin activity increases in all subjects after prolonged fasting, as well as after treatment with the PPARα agonist fenofibrate. In mice, absence of vanin-1 exacerbates the fasting-induced increase in hepatic triglyceride levels. Similarly, inhibition of vanin activity in rats induces accumulation of hepatic triglycerides upon fasting. Microarray analysis reveal that the absence of vanin-1 associates with gene sets involved in liver steatosis, and reduces pathways involved in oxidative stress and inflammation. We show that hepatic vanin-1 is under extremely sensitive regulation by PPARα and that plasma vanin activity could serve as a readout of changes in PPARα activity in human subjects. In addition, our data propose a role for vanin-1 in regulation of hepatic TG levels during fasting

SUCNR1-mediated chemotaxis of macrophages aggravates obesity-induced inflammation and diabetes.

Obesity induces macrophages to drive inflammation in adipose tissue, a crucial step towards the development of type 2 diabetes. The tricarboxylic acid (TCA) cycle intermediate succinate is released from cells under metabolic stress and has recently emerged as a metabolic signal induced by proinflammatory stimuli. We therefore investigated whether succinate receptor 1 (SUCNR1) could play a role in the development of adipose tissue inflammation and type 2 diabetes. Succinate levels were determined in human plasma samples from individuals with type 2 diabetes and non-diabetic participants. Succinate release from adipose tissue explants was studied. Sucnr1 -/- and wild-type (WT) littermate mice were fed a high-fat diet (HFD) or low-fat diet (LFD) for 16 weeks. Serum metabolic variables, adipose tissue inflammation, macrophage migration and glucose tolerance were determined. We show that hypoxia and hyperglycaemia independently drive the release of succinate from mouse adipose tissue (17-fold and up to 18-fold, respectively) and that plasma levels of succinate were higher in participants with type 2 diabetes compared with non-diabetic individuals (+53%; p < 0.01). Sucnr1 -/- mice had significantly reduced numbers of macrophages (0.56 ± 0.07 vs 0.92 ± 0.15 F4/80 cells/adipocytes, p < 0.05) and crown-like structures (0.06 ± 0.02 vs 0.14 ± 0.02, CLS/adipocytes p < 0.01) in adipose tissue and significantly improved glucose tolerance (p < 0.001) compared with WT mice fed an HFD, despite similarly increased body weights. Consistently, macrophages from Sucnr1 -/- mice showed reduced chemotaxis towards medium collected from apoptotic and hypoxic adipocytes (-59%; p < 0.05). Our results reveal that activation of SUCNR1 in macrophages is important for both infiltration and inflammation of adipose tissue in obesity, and suggest that SUCNR1 is a promising therapeutic target in obesity-induced type 2 diabetes

Flexible Release Composition using Integer Linear Programming

For software vendors, the process to determine the requirements for the next release of a software product is often difficult. In this paper we present a mathematical formalization of release composition with a corresponding optimization tool that aims to support product managers and development project managers during release planning. The too