Technology product evolution and the diffusion of new product features

The evolution of technology products can be analysed on multiple levels. Product categories go through continuous evolution determined by the cumulative changes in the features of new product models. This is manifested in the diffusion of new product features and in the increasingly vague boundaries between different product generations. This article develops an approach for planning and forecasting technology product evolution and the diffusion of new product features. This is achieved by isolating the phenomena underlying the evolution process, and formulating the process at the product category, product feature, and product model levels. The approach is derived from these formulations combining the primarily demand-driven product category diffusion and product unit replacement behaviour, and the more supply-driven product feature dissemination. The approach enables meaningful sensitivity analysis including the analysis of discontinuities. The developed approach is applied to characterise the evolution of an example product category of mobile handsets and to forecast the diffusion of mobile handset features using extensive longitudinal and cross-sectional data collected from Finland. In consequence, the process of technology product evolution and the phenomenon of product feature dissemination are suggested as extensions to research on product category diffusion and replacement.     

Community-Based Tradable Permits for Localized Pollution

This paper considers the assignment of tradable permits—representing property rights of an environmental good—to community members who are harmed by pollution generated by firms. These community members can in turn sell permits to polluters according to their personal preferences. For a special case with a sole household, market transactions between the household and polluters achieve an efficient pollution level. However, for a group of households, the decentralized market solution fails to yield social efficiency because of competitive consumption of the environmental goods. We design a revenue-sharing mechanism akin to unitization, under which market transactions also achieve efficient resource allocation. Importantly, in some cases, efficiency can be achieved even when regulators are ignorant of the private valuation of the environmental good.     

Representation and aggregation of preferences under uncertainty

We axiomatize in the Anscombe-Aumann setting a wide class of preferences called rank-dependent additive preferences that includes most known models of decision under uncertainty as well as state dependent versions of these models. We prove that aggregation is possible and necessarily linear if and only if (society's) preferences are uncertainty neutral. The latter means that society cannot have a non-neutral attitude toward uncertainty on a subclass of acts. A corollary to our theorem is that it is not possible to aggregate multiple prior agents, even when they all have the same set of priors. A number of ways to restore the possibility of aggregation are then discussed.     

Using Tucker’s theorem of the alternative to simplify,review and expand discrete arbitrage theory

For valuing derivatives and other assets in securities and commodities markets, arbitrage pricing theory has been a major approach for decades. This paper derives fundamental arbitrage pricing results in finite dimensions in a simple unified framework using Tucker’s theorem of the alternative. Frictionless results, that is perfect market results, plus imperfect market results such as those with dividends, periodic interest payments, transaction costs, different interest rates for lending and borrowing, shorting costs and constrained short selling are presented. While the results are mostly known and appear in various places, our contribution is to present them in a coherent and comprehensive fashion with very simple proofs. The analysis yields a simple procedure to prove new results and some are presented for cases with imperfect market frictions.     

A Method to Evaluate Mode Effects on the Mean and Variance of a Continuous Variable in Mixed‐Mode Surveys

Les enquêtes à mode de collecte mixte, dans lesquelles le choix du mode de réponse est laissé aux personnes interrogées, sont de plus en plus répandues. Cette possibilité du choix du mode de réponse peut induire une confusion entre deux sortes d'effets : les effets de sélection et les effets de mesure. L'estimation séparée de ces deux effets est impossible à partir des seules données d'une enquête à mode de collecte mixte. Dans cet article, nous montrons comment la même estimation devient possible à partir d'une comparaison entre les résultats d'une enquête à mode de collecte mixte et ceux d'un enquête à mode de collecte unique basées sur le même questionnaire. La méthode que nous proposons permet d'estimer l'effet du mode de réponse sur la moyenne et la variance d'une variable de réponse continue. Elle est illustrée par l'estimation des effets du mode de réponse sur six questions relatives aux opinions vis‐à‐vis des enquêtes.     

Effectiveness and safety of betrixaban extended prophylaxis for venous thromboembolism compared with standard-duration prophylaxis intervention in acute medically ill patients: a systematic literature review and network meta-analysis

Abstract

Aims: To determine the clinical effectiveness and safety of venous thromboembolism (VTE) prophylaxis using US- and Europe-approved anticoagulants relative to extended-duration VTE prophylaxis with betrixaban. Low molecular weight heparins (LMWHs), unfractionated heparin (UFH), fondaparinux sodium and placebo were each compared to betrixaban, as standard-duration VTE prophylaxis for hospitalized, non-surgical patients with acute medical illness at risk of VTE.

Materials and methods: A systematic literature review was conducted up to June 2019 to identify randomized controlled trials (RCTs) of VTE prophylaxis in hospitalized, non-surgical patients with acute medical illness at risk of VTE. Studies that reported the occurrence of VTE events (including death) and, where possible, major bleeding, from treatment initiation to 20–50?days thereafter were retrieved and extracted. A Bayesian fixed effect network meta-analysis was used to estimate efficacy and safety of betrixaban compared with standard-duration VTE prophylaxis.

Results: Seven RCTs were analyzed which compared betrixaban, LMWHs, UFH, fondaparinux sodium, or placebo. There were significantly higher odds (median odds [95% credible interval]) of VTE with LMWHs (1.38 [1.12–1.70]), UFH (1.60 [1.05–2.46]), and placebo (2.37 [1.55–3.66]) compared with betrixaban. There were significantly higher odds of VTE-related death with placebo (7.76 [2.14–34.40]) compared with betrixaban. No significant differences were observed for the odds of major bleeding with all comparators, VTE-related death with any active standard-duration VTE prophylaxis, or of VTE with fondaparinux sodium, compared with betrixaban.

Limitations and conclusions: In this indirect comparison, betrixaban was shown to be an effective regimen with relative benefits compared with LMWHs and UFH. This indicates that betrixaban could reduce the burden of VTE in at-risk hospitalized patients with acute medical illness who need extended prophylaxis, though without direct comparative evidence, stronger conclusions cannot be drawn.     

Writing on the Wall: Street Art in Graffiti‐free Singapore

The legalization of graffiti in many cities has impacted urban landscapes and the way artists and the public view graffiti, street art and the city as well. This article considers the genesis, process and consequences of legal walls programmes firstly by introducing and differentiating the key terms ‘graffiti’, ‘street art’ and ‘legal walls’, then by examining an empirical case, that of Singapore. Renowned as a graffiti‐averse and litter‐free city, Singapore's recent about‐turn in legalizing illicit art forms illustrates changing government perspectives on creativity and legality in the country. Why the government has effected this change, how artists and members of the public have responded to it and the resultant art forms are critically explored. The conclusion reflects on four key lessons from Singapore for cities in general.     

Linking improved knowledge management to operational and organizational performance

This research empirically examines the importance of knowledge management processes to operational and overall organizational performance (OPERF). Specifically, results indicate that a shared interpretation of knowledge among operational personnel mediates how knowledge is disseminated and used to design and implement a unified operational response to that knowledge. Further, results collected in a logistics operations (LO) context support a strong positive relationship between this knowledge management process and operational and organizational performance. Importantly, psychometric measures for organizational performance collected from managerial respondents were strongly correlated with secondary financial data for participating firms obtained from Compustat, thus supporting a link about operational performance and hard organizational performance data.     

An empirical database for a general equilibrium model of the European Communities

We document the main features of a database that has been constructed for use in an applied general equilibrium model. The model is designed to evaluate policies of the European Community (EC), including membership. The database includes each of the major members of the EC in the 1970's: Germany, France, Italy, the Netherlands, Belgium, the United Kingdom, Denmark and Ireland. It also includes three further trading regions: the United States, Japan and a residual Rest of World. Four aspects of our database are documented. The first is the collection and use of “raw data” from a number of sources for 1975. The second aspect is the generation of a multi-year database, with 1975 serving as a “reference year” for temporal updates to more recent years. The third aspect is the application of the database to the calibration of a “generic” general-equilibrium trade model. The final aspect is the use of the database to study the historical accession of the United Kingdom to the EC.