Brayton cycle 3.2-inch radial compressor performance evaluation

Brayton cycle 3.2 inch radial compressor performance evaluation over wide range of Reynolds number

On the Estimation of Euler Equations in the Presence of a Potential Regime Shift

The concept of a peso problem is formalized in terms of a linear Euler equation and a nonlinear marginal model describing the dynamics of the exogenous driving process. It is shown that, using a threshold autoregressive model as a marginal model, it is possible to produce time-varying peso premia. A Monte Carlo method and a method based on the numerical solution of integral equations are considered as tools for computing conditional future expectations in the marginal model. A Monte Carlo study illustrates the poor performance of the generalized method of moment (GMM) estimator in small and even relatively large samples. The poor performance is particularly acute in the presence of a peso problem but is also serious in the simple linear case.peso problem; Euler equations; GMM; threshold autoregressive models

Guest editorial

The 21st International EurOMA (EurOMA, 2014) Conference was hosted by Università degli Studi di Palermo. The conference theme was Operations Management in an Innovation Economy. According to innovation economists what primarily drives economic growth in today’s knowledge-based economy is not capital accumulation but innovative capacity spurred by appropriable knowledge and technological externalities. Economics growth in innovation economics is the end- product of knowledge, R&D expenditures, licenses, technological spillovers, and externalities between collaborative firms, i.e. supply chains and networks of innovation. When firms do not explicitly acknowledge and manage their operations as a concurrent activity to the management of innovation, they often encounter problems late in product development, or with manufacturing launch, logistical support, quality control, and production costs. As such, innovation process and operations management should be coordinated, rather than being viewed as separate sets of decisions and activities. We received 592 abstracts and used a doubled-blind review process, involving 127 members of the Scientific Committee, to review 586 abstracts (six abstracts were desk rejected) and provide feedback to the authors. Of these, 513 were accepted and 73 rejected. The accepted abstracts resulted in 405 full papers in the Scientific Programme. With three papers subsequently withdrawn, there were 402 paper presentations in prospect. The most recurrent OM themes were: sustainability in operations and logistics (42 papers); supply chain management (35 papers); innovation, product and service development (32 papers); managing inter-firm relationships in supply chains (30 papers); healthcare OM (21 papers); lean and agile operations (21 papers). The Scientific Programme incorporated 134 parallel sessions and was enriched by two keynote speakers: Professor Robert Handfield (Bank of America University Distinguished Professor of Supply Chain Management, North Carolina State University) and the Chief Operations Officer of Luxottica, Massimo Vian, who provided insightful reflections on the conference theme from their academic and industry perspectives, respectively. In addition there were six special sessions providing unique opportunities for engagement and insights on teaching in OM, crowdsourcing and open innovation in OM, OM as practice, OM research in the fashion industry, new supply chains, and the role of social media in OM and EurOMA. Also, besides this interesting topic-specific special sessions, the conference hosted a “Meet the Editors” session with editors and co-editors from eight OM journals

Introducing \u201chealthcare resilience\u201d in clinical risk management

This paper reports the results of an explorative case study in an Italian hospital and presents a conceptual framework for healthcare resilience, which clarifies why and how healthcare structures need to be resilient in order to fully deal with clinical risk. In other words, it is not sufficient to take the \u201cpath to zero harm\u201d. Healthcare companies have also to pursue strategies for maximizing the organizational resilience, in terms of resistance, reliability, redundancy and flexibility. This is quite important because, no matter which CRM technique and/or best practice is adopted, sometime adverse events occur. And, in this case, being resilient can help in dampening their negative consequences. By extending the focus of traditional clinical risk management to different kinds of risk sources (not just patient safety threats) and to different kinds of risk minimization strategies (not just minimize the likelihood of occurrence but also the risk magnitude) this paper contributes to the literatures on operations management in healthcare. The conceptualization of \u201chealthcare resilience\u201d and the in-depth case results allow us to offer a number of suggestions and ideas for developing further research in the field of healthcare operations management

Factors influencing the pricing of applications in the Apple App Store: A developers\u2019 perspective

Many know how Apple Inc. owes its success in Mobile Commerce to the introduction of the new \u201cApp Store\u201d business model. This new market is characterized by the opening to third party mobile apps, which are distributed to consumers through the App Store. This paper investigates factors that might influence the pricing of applications in the Apple Mobile Application Store. By reviewing the existing literature on the issue and analyzing the strategic features characterizing the App Store, we detect three main factors that could influence prices for apps, that is the number of developed apps, the presence of two-sided network externalities and developer\u2019s specialization. An empirical analysis on data from 68,220 apps downloaded from the Italian App Store is used to test the hypotheses. Regression results support our hypotheses. We argue, that even if the research here presented can be considered as a started analysis to the pricing problem in such markets, this work may have important managerial implication for the thousands of developers that are competing in this emerging market

Evaluating collapse fragility curves for existing buildings retrofitted using seismic isolation

Few studies have investigated so far the collapse capacity of buildings with base-isolation. In such studies, preliminary considerations have been drawn based on a number of assumptions regarding: (i) the methodology used for assessing the collapse capacity, (ii) the collapse conditions and failure modes assumed for both superstructure and isolation system, and (iii) the numerical modeling assumptions. The main results pointed out that the collapse conditions of base-isolated buildings may occur for intensity levels slightly higher than those associated with the design earthquake. In this paper, further developments are made through the use of enhanced models for the description of the behavior of a rubber-based isolation system and the assumption of more rational collapse conditions. Collapse fragility functions, in terms of mean and dispersion values, are proposed for two archetypes representative of existing buildings retrofitted using the seismic isolation technique. The collapse margin ratio (median collapse capacity Sa, C, namely the spectral acceleration associated to a probability of exceedance equal to 50%, divided by the design spectral acceleration at the collapse prevention limit state) has been evaluated for each examined case-study. Values ranging from 1.10 to 1.45 were found

Utilising Features of Sport Commentating to Provide a Framework for Co-Teaching the Online Lecture

Higher education teaching abruptly changed during the COVID-19 pandemic to remote, on-line learning and teaching. The use of on-line communication software to teach became the norm and remains at many institutions. This software contains features, such as the chat, that offer teaching and learning advantages; however, potential benefits can be challenging to realise for academics used to traditional modes of lecture delivery. In most cases a solo-taught lecture designed for a physical room does not transition well to the on-line space. Co-teaching, which involves two or more academics teaching the same class, is a pedagogy that can improve engagement and satisfaction for students and academics alike. However, how co-teaching can transition to the on-line space and take full benefit of the communication software features is not well known. We recognised that some aspects of sports announcing (commentating) align with desirable qualities of co-teaching on-line. In this paper we use these features to develop a practical framework for co-teaching in the on-line space and evaluate the model in a second-year university science subject. Using data from student surveys, we found that the co-teaching model helped integrate the chat functionality into the main lecture and led to improved engagement and enjoyment of on-line classes. The model also assisted students in identifying key learning outcomes. Using the framework as a practical guide for how to incorporate co-teaching into on-line classes helps realise the benefits of contemporary communication software