Task‐based structures in open source software: revisiting the onion model

Studies on Open Source Software (OSS) developer communities have long stated that there is a relationship between community structure and tasks carried out by project members. This relationship has been exemplified by the onion model, which has been instrumental in understanding self‐coordination in OSS projects. Despite its ubiquity, there is a lack of empirical evidence to validate the relative position of each task cluster within the onion model. In this study, we map out the community structure of a large open source project and observe its bug‐fixing patterns to explore the relationship between tasks and structure. Our study makes three significant contributions. First, we find no empirical evidence to support the structural location of bug‐fixing tasks in the onion structure. Second, we find empirical evidence to support the core‐periphery continuum model linking an actor’s coreness to problem‐solving ability. Third, our results suggest that the importance and location of each task within the core‐periphery structure evolve over time. These findings add clarity to the community structure and their implications for the management and coordination of collaborative innovation projects.     

Understanding the intellectual structure and evolution of Competitive Intelligence: a bibliometric analysis from 1984 to 2017

ABSTRACT

Competitive Intelligence (CI) is a relatively novel discipline that is generating a growing interest in the field of strategic management. Its novelty, approach and origin have meant that the definition of the CI entails different interpretations and utilities depending on the audience. This research develops a conceptual analysis of CI in literature by quantifying the bibliometric performance indicators, identifying the main authors, countries, journals and research areas and evaluating the intellectual structure and evolution of the discipline using SciMAT as bibliometric analysis software. The bibliometric performance analysis is focused on the citation-based impact of the scientific output, while the science mapping illustrates the evolution of the research themes that build the discipline through the use of bibliometric network analysis techniques. To this purpose, the publications related to CI from 1984 to 2017 available at Scopus have been retrieved (5,275 publications). Finally, it offers a framework to support future researches.     

Granger causality detection in high-dimensional systems using feedforward neural networks

This paper proposes a novel methodology to detect Granger causality on average in vector autoregressive settings using feedforward neural networks. The approach accommodates unknown dependence structures between elements of high-dimensional multivariate time series with weak and strong persistence. To do this, we propose a two-stage procedure: first, we maximize the transfer of information between input and output variables in the network in order to obtain an optimal number of nodes in the intermediate hidden layers. Second, we apply a novel sparse double group lasso penalty function in order to identify the variables that have the predictive ability and, hence, indicate that Granger causality is present in the others. The penalty function inducing sparsity is applied to the weights that characterize the nodes of the neural network. We show the correct identification of these weights so as to increase sample sizes. We apply this method to the recently created Tobalaba network of renewable energy companies and show the increase in connectivity between companies after the creation of the network using Granger causality measures to map the connections.     

Trade liberalization,tariff redundancy and inflation: A methodological exploration applied to Argentina

Zusammenfassung Handelsliberalisierung, Zollredundanz und Inflation: Eine auf Argentinien angewandte methodologische Untersuchung. — Der Hauptzweck dieser Arbeit besteht darin, einen einfachen Rahmen für die Analyse der Auswirkungen verschiedener Ma\nahmen der Importliberalisierung auf die Wettbewerbsf?higkeit des gewerblichen Sektors zu entwickeln. Im Fall von Argentinien wird gezeigt, da\ das Hauptinstrument zur Beseitigung der Zollredundanz die Wechselkurspolitik der Regierung war. Zollsenkungen waren von zweitrangiger Bedeutung. Die Zollredundanz scheint bis Anfang 1979 beseitigt gewesen zu sein, zu einer Zeit, in der die Beh?rden begannen, diskriminierende Zollsenkungen vorzunehmen. Aus der Redundanzanalyse ergeben sich Hinweise auf das Ausmaβ der m?glichen Abschw?chung der Preissteigerungsrate, die bei langfristiger Konvergenz der in- und ausl?ndischen Preise erwartet werden kann. Konvergenzberechnungen, die auf der Kaufkraftparit?ten-these basieren, k?nnen anscheinend nur dann korrekt verwendet werden, wenn die Preise einzelner Produkte auf den in- und ausl?ndischen M?rkten verglichen werden. Die dargestellten Methoden k?nnen zwar verbessert werden, aber die wichtigsten Folgerungen für die Politik dürften sich bereits aus der durchgefìhrten Analyse klar ergeben.

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Résumé La libéralisation du commerce, l’excédent tarifaire, et l’inflation: une exploration méthodologique appliquée à l’Argentine. — Le but principal de cet article est présenter un cadre simple pour analyser l’impacte des plusieurs mesures de libéralisation d’importation sur la capacité de concurrence potentielle du secteur industriel. Pour l’Argentine, les auteurs démontrent que l’instrument clef pour éliminer l’excédent tarifaire était la politique de taux de change des autorités. Les réductions des tarifs externes étaient moins importantes. Il semble clair que les autorités avaient éliminé l’excédent tarifaire au début de 1979, au moment où ils commen?aient à réduire les tarifs d’une manière discriminatoire. L’analyse de l’excédent indique la mesure possible de la décélération de prix qui peut être attendue sous la condition d’une convergence de prix à long terme. Actuellement il para?t que les calculs de convergence qui basent sur la thèse de PPA peuvent être appliqués correctement seulement si les prix des biens individuels sur les marchés internationaux et locaux sont comparés. En effet la méthodologie présentée ici peut être perfectionnée, mais cette analyse devrait déjà avoir montré les principales implications politiques.

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Resumen Liberalization del comercio, redundancia tarifaria e inflación: una exploration metodológica aplicada a la Argentina. — El propósito principal de este artículo es presentar un marco simple para analizar el impacto de varias medidas de liberalización de importaciones sobre la competitividad potencial del sector industrial. En el caso de Argentina se demuestra que el instrumenta clave al eliminar la redundancia tarifaria fue la política cambiaria de las autoridades. Las reducciones en las tarifas extemas fueron de importancia secundaria. Parece claro que la redundancia tarifaria había sido eliminada ya a principios de 1979, en una época en que las autoridades comenzaron a aplicar reducciones tarifarias discriminatorias. El análisis de redundancia indica el posible monte de desaceleracion de precios que puede esperarse bajo una convergencia de precios de largo plazo. En verdad pareciera que los cálculos de convergencia basados en la tesis PPP pueden ser utilizados correctamente solo cuando se comparan precios de productos individuates en los mercados international y doméstico. La metodología presentada aquí puede ser refinada de varias maneras, pero las principales implicaciones de política deberian quedar claras de acuerdo al análisis precedente.

     

Imitation—theory and experimental evidence

We introduce a generalized theoretical approach to study imitation and subject it to rigorous experimental testing. In our theoretical analysis we find that the different predictions of previous imitation models are mainly explained by different informational assumptions, and to a lesser extent by different behavioral rules. In a laboratory experiment we test the different theories by systematically varying information conditions. We find significant effects of seemingly innocent changes in information. Moreover, the generalized imitation model predicts the differences between treatments well. The data provide support for imitation on the individual level, both in terms of choice and in terms of perception. Furthermore, individuals’ propensity to imitate more successful actions is increasing in payoff differences.     

Nutrient composition of selected fresh and processed fish species from lake Malawi: a nutritional possibility for people living with HIV/AIDS

Nutrition is important for both healthy and sick people. Unfortunately for sick people, especially those living with HIV/AIDS, the emphasis has mostly been on drugs at the expense of nutritional aspects. People living with HIV/AIDS and related diseases need a lot of protein and energy‐rich foods together with vitamins and minerals. Fish are particularly rich in these nutrients. In Malawi, fish are harvested in large numbers and to avoid deterioration, some are smoked, sun dried or partially boiled and then sun dried. Since the nutrient contents of the fresh and processed fish may differ, a study was carried out on four different fresh and processed fish species (Copadichromis inornatus, Rhamphochromis ferox, Engraulicypris sardella and Oreochromis lidole) in order to determine which species was the more nutritive. The results showed that E. sardella and C. inornatus species, fresh or processed, had relatively higher (P < 0.001) protein content (58.22 ± 0.6% and 57.78 ± 0.7% respectively), fat (25.2 ± 1.2 and 22.08 ± 0.4% respectively), energy (24086.7 ± 151.7 J/g and 22204.9 ± 84.7 J/g respectively) than either R. ferox or O. lidole. Although the R. ferox species had lower protein, fat and energy than E. sardella or C. inornatus, this species had higher available lysine content. Calcium and magnesium contents of E. sardella and C. inornatus were however, slightly lower (P < 0.001) than those of the other two species. There were variations between and within the species for all parameters analysed. The results obtained in this work suggest that people living with HIV/AIDS in Malawi can best build their muscle and get more energy and minerals from the E. sardella and C. inornatus fish species. It would therefore be recommended that appropriate technologies for improving the availability and productivity of such fish should be developed and tested for people living with HIV/AIDS or affected households. However, it is suggested that a larger group of the commonly available fish species should be analysed so as to offer a wider choice to consumers.     

Country Risk,Regulation, and Liquidity Transformation in Palestine and Neighboring Countries

This study analyzes the impact of economic, financial, and political instability on the liquidity transformation of banks operating in unstable environments. Our main goal is to assess the relationship between overall risk in a country and liquidity transformation. With this goal in mind, we use a sample of five Middle Eastern countries during the period 2005–2010. Our results showed that the high-risk environment has a significant and negative impact on both liquidity transformation and the extension of credit. In addition, we conclude that high capital requirements may reduce further lending, while imposing liquidity requirements seems to be a better strategy for enhancing liquidity transformation.     

A Study of the Interaction of Insurance and Financial Markets: Efficiency and Full Insurance Coverage

The first contribution of this article is to provide a framework, a model together with a corresponding equilibrium notion, suitable for the study of the interaction between insurance and dynamic financial markets. Our central result is that in equilibrium risk‐averse agents purchase full insurance coverage, despite unfair insurance prices. We identify three conditions that explain this result: (1) insurance contracts are priced competitively, (2) financial prices include a risk premium only for undiversifiable risk, and (3) financial markets are effectively complete. An implication is that in this model disasters can be insured by fully assessable stock insurance companies.     

Barriers to innovation and public policy in Catalonia

The present paper analyses the link between firms’ decisions to innovate and the barriers that prevent them from being innovative. The aim is twofold. First, it analyses three groups of barriers to innovation: the cost of innovation projects, lack of knowledge and market conditions. Second, it presents the main steps taken by Catalan Government to promote the creation of new firms and to reduce barriers to innovation. The data set used is based on the 2004 official innovation survey of Catalonia which was taken from the Spanish CIS4 sample. This sample includes individual information on 2,954 Catalan firms in manufacturing industries and knowledge-intensive services (KIS). The empirical analysis reveals pronounced differences regarding a firm’s propensity to innovate and its perception of barriers. Moreover, the results show that cost and knowledge barriers seem to be the most important and that there are substantial sectoral differences in the way that firms react to barriers. The results of this paper have important implications for the design of future public policy to promote entrepreneurship and innovation together.