Dealing with Endogeneity to Understand the Societal Impact of the Third Sector: Why Should We Care and What Can We Do about It?

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Endogeneity is often regarded as a key barrier in establishing the causal relationship between the third sector and its...     

MRP system performance under lumpy demand environments

Material requirements planning (MRP) systems are deemed to deal with master schedules with lumpy demand patterns better than any other production scheduling system. Past studies have advocated important advantages of using MRP systems. The objective of this paper is to look into the impact of patterns of demand lumpiness on the performance of MRP systems by a simulation study. Results show that there is an important threshold point in terms of degree of lumpiness at which MRP system performance starts to deteriorate in the operating conditions considered. If master production schedules (MPS) can be controlled by manufacturers, MRP users should exercise caution to introduce demand lumpiness in MPS to improve system performance. If not, MRP users should then examine the given lumpiness and choose an appropriate lot-sizing rule that has been shown to take advantage of the effect of demand lumpiness.     

Labels and leaders: The influence of framing on leadership emergence

In two studies, this paper examines the influence of task framing on leadership emergence in mixed-gender dyads. In Study 1, we found that males are more likely to emerge as leaders when a paper-folding task is framed as masculine (i.e., Building Project) relative to feminine (i.e., Art Project). Furthermore, females are more likely to emerge as leaders when a paper-folding task is framed as feminine relative to masculine. In Study 2, we conceptually replicate these results using a weaving task (framed as Knot-Tying Task vs. Hair-Braiding Task) and find that perceived competence is the mechanism through which task framing affects leadership emergence. Taken together, these results suggest that task framing can influence the emergence of leaders because of changes in perceptions of competence. These findings are discussed in the context of related theoretical findings and managerial implications are elaborated on.     

Transforming the exponential by minimizing the sum of the absolute differences

This work presents an optimal value to be used in the power transformation to transform the exponential to normality for statistical process control (SPC) applications. The optimal value is found by minimizing the sum of absolute differences between two distinct cumulative probability functions. Based on this criterion, a numerical search yields a proposed value of 3.5142, so the transformed distribution is well approximated by the normal distribution. Two examples are presented to demonstrate the effectiveness of using the transformation method and its applications in SPC. The transformed data are almost normally distributed and the performance of the individual charts is satisfactory. Compared to charts that use the original exponential data and probability control limits, the individual charts constructed using the transformed distribution are superior in appearance, ease of interpretation and implementation by practitioners.     

A unified sequential test procedure for simultaneous testing the equality of several binomial proportions to a specified standard

In this article, we propose a unified sequentially rejective test procedure for testing simultaneously the equality of several independent binomial proportions to a specified standard. The proposed test procedure is general enough to include some well-known multiple testing procedures such as the Ordinary Bonferroni procedure, Hochberg procedure and Rom procedure. It involves multiple tests of significance based on the simple binomial tests (exact or approximate) which can be easily found in many elementary standard statistics textbooks. Unlike the traditional Chi-square test of the overall hypothesis, the procedure can identify the subset of the binomial proportions, which are different from the prespecified standard with the control of the familywise type I error rate. Moreover, the power computation of the procedure is provided and the procedure is illustrated by two real examples from an ecological study and a carcinogenicity study.     

Incongruent migration categorisations and competing citizenship claims: ‘return’ and hypermigration in transnational migration circuits

ABSTRACT

Recent scholarly interventions propose that the principle of jus nexi (effective connections) or jus domicile (domicile) should replace birthright or birthplace considerations when assigning citizenship status and political membership. Nonetheless, both views privilege notions of territorial presence and the ideal of political community. This paper focuses on Mainland Chinese return migration from Canada to metropolitan cities in China. The dual citizenship restriction enforced by China means those that naturalised in Canada have relinquished their right to Chinese citizenship. Should they be considered returnees, immigrants or transnational sojourners in their ancestral homeland? It is this incongruence in migration categorisations compared to migrant life-worlds that this paper aims to examine. The paper also highlights the interface of competing claims to citizenship in the context of Chinese internal migration and new (African) immigration in China, as well as the returnees’ own transnational migration across the lifecourse. It argues that the ordering mechanisms that characterise normative conceptions of citizenship focus on isolated types of migration trends whereas what confronts us more urgently are intersecting migration configurations that underline the incongruence of migration categorisations and the complexity of competing citizenship claims spatially and temporally.     

Temporalities,materialities and connecting locales: migration and mobility in Asia-Pacific cities

ABSTRACT

In this introduction, we argue that paying attention to the heterogeneous and multi-directional characteristics of mobilities in the Asia-Pacific can generate new conceptual and empirical insights for research on migration and mobility, transnationalism, and intercultural encounters. We note that temporality and materiality are productive lenses for connecting research across diverse urban locales, and to understand the changes these locales experience as a result of emerging forms of mobility. We also draw out three key themes that emerge from the analyses presented by papers in this special issue, and which link the papers as a collection. First, the collection challenges conventional ways in which migrant and non-migrant subjects are classified and researched, by working within the conceptual space opened up by arguments against ‘migrant exceptionalism’, on the one hand, claims for the centrality of the ‘figure of the migrant’ on the other. Second, the papers implicitly or explicitly unpack the temporal, spatial and material consequences of migration and mobility in terms of how aspirations manifest materially and through affective encounters. Third, the collection as a whole signals the analytic power of connecting seemingly distinct sites and scales in and through which migration and mobility take place.     

Reliable Supply Chain Network Design

Risk management in supply chains has been receiving increased attention in the past few years. In this article, we present formulations for the strategic supply chain network design problem with dual objectives, which usually conflict with each other: minimizing cost and maximizing reliability. Quantifying the total reliability of a network design is not as straightforward as total cost calculation. We use reliability indices and develop analytical formulations that model the impact of upstream supply chain on individual entities’ reliability to quantify the total reliability of a network. The resulting multiobjective nonlinear model is solved using a novel hybrid algorithm that utilizes a genetic algorithm for network design and linear programming for network flow optimization. We demonstrate the application of our approach through illustrative examples in establishing tradeoffs between cost and reliability in network design and present managerial implications.     

Urbanization and Land‐Use Change: A Human Ecology of Deforestation Across the United States, 2001–2006

Drawing from human ecology, the present study sheds light on the ways in which urbanization drives changes in forest cover at the local level across the continental United States. Using county‐level data from the National Land Cover Database and other US governmental sources, the area of forest cover lost in the construction of the built environment between 2001 and 2006 is regressed on the size, density, and social organization of a locality. Controlling for several other factors, estimates from spatial regression models with two‐way fixed effects show that increasing density slowed down deforestation, while variables representing size and social organization had the opposite effect. Based on these results, urbanization is framed as a multidimensional human ecological process with countervailing impacts on the natural environment.