A neural network clustering model for miscellaneous components production planning

The growing importance of providing service to customers, e.g. post-sale assistance, supplying of spare parts, upgrading and integration of new elements in installed systems, enhances the importance of planning and management of upgrading parts in most manufacturing industries. These parts are generally characterized by high technical heterogeneity and have a highly variable and difficult to forecast demand. In some areas (especially the most dynamic, e.g. high-tech products), these kinds of components are quite common, and represent a very strong relation between the manufacturing firm and the market. These parts are generally too many to be efectively supported on a planning database system with individual records and too heterogeneous ( and sometimes with a too high value) to be supported all together in a single record. In this paper, we want to study the application of adaptive techniques for the clustering of these components in classes based on the similarities in their market behaviour in order to build an optimal database for planning production and supplying of these components.     

Uniformly most powerful unbiased test for shoulder condition in point transect sampling

Point transect sampling is a well-known methodology for estimating wildlife population density. In this context, the usual approach is to assume a model for the detection function. Thus, the estimate depends on the shape of the detection function. In particular, the estimation is influenced by the so-called shoulder condition, which guarantees that detection is nearly certain at small distances from the observer. For instance, the half-normal model satisfies this condition, whereas the negative exponential model does not. Testing whether the shoulder condition is consistent with data is a crucial issue. In this paper we propose the uniformly most powerful unbiased test for the shoulder condition in the exponential mixture model of the half-normal and the negative exponential. Critical values of the proposed test are calculated for large samples by means of asymptotic distribution theory and for small samples via Monte Carlo simulations. Finally, a case study is presented.     

Trust and partner selection in social networks: An experimentally grounded model

This article investigates the importance of the endogenous selection of partners for trust and cooperation in market exchange situations, where there is information asymmetry between investors and trustees. We created an experimental-data driven agent-based model where the endogenous link between interaction outcome and social structure formation was examined starting from heterogeneous agent behaviour. By testing various social structure configurations, we showed that dynamic networks lead to more cooperation when agents can create more links and reduce exploitation opportunities by free riders. Furthermore, we found that the endogenous network formation was more important for cooperation than the type of network. Our results cast serious doubt about the static view of network structures on cooperation and can provide new insights into market efficiency.     

How much reliable are the integrated ‘live’ data? A validation strategy proposal for the non-parametric micro statistical matching

The integration of different data sources is a widely discussed topic among both the researchers and the Official Statistics. Integrating data helps to contain costs and time required by new data collections. The non-parametric micro Statistical Matching (SM) allows to integrate ‘live’ data resorting only to the observed information, potentially avoiding the misspecification bias and speeding the computational effort. Despite these pros, the assessment of the integration goodness when we use this method is not robust. Moreover, several applications comply with some commonly accepted practices which recommend e.g. to use the biggest data set as donor. We propose a validation strategy to assess the integration goodness. We apply it to investigate these practices and to explore how different combinations of the SM techniques and distance functions perform in terms of the reliability of the synthetic (complete) data set generated. The validation strategy takes advantage of the relation existing among the variables pre-and-post the integration. The results show that ‘the biggest, the best’ rule must not be considered mandatory anymore. Indeed, the integration goodness increases in relation to the variability of the matching variables rather than with respect to the dimensionality ratio between the recipient and the donor data set.     

Business Performance Analytics: exploring the potential for Performance Management Systems

Business Performance Analytics (BPA) entails the systematic use of data and analytical methods (mathematical, econometric and statistical) for performance measurement and management. Although potentially overcoming some traditional diagnostic issues related to Performance Management Systems (PMS), such as information overload, absence of cause-effect relationships, lack of a holistic view of the organisation, research in the field is still in its infancy. A comprehensive model for operationalising analytics for diagnostic and interactive PMS is still lacking. Adopting an action research approach, this paper addresses this gap and develops a five-step framework applied to a company operating in the construction industry. The results show that in addition to encouraging dialogue, BPA can contribute to identifying critical performance variables, potential sources of risk and related interdependencies. A number of critical issues in implementing data-based approaches are also highlighted, including data quality, organisational competences and cultural shifts.     

A Structural Equation Model Estimation of the Role of Social Vulnerability as a Predictor of People’s Feelings of Unsafety

Social Indicators Research - People’s perception of insecurity is linked to a wide range of factors and up-to-date sources stress the impact of socially constructed concerns on feelings of...     

Development and Spanish translation of the Weinberg Center Risk and Abuse Prevention Screen (WC-RAPS)

Barriers for enhanced detection, identification, and reporting of elder abuse include the paucity of appropriate, valid, easily administered screening tools. This article describes the qualitative methods used in the development of the Weinberg Center Risk and Abuse Prevention Screen (WC-RAPS), and of its Spanish version. Focus groups and cognitive interviews were instrumental in identifying problematic items, underscoring potential response errors, and informing about putative causes for divergent interpretations of item-intent. Seven of the 11 original items were modified, a double-barreled item was segregated into two, one item deleted, and three additional items included to create the final 13 WC-RAPS items. The multi-step approach implemented for the Spanish conversion evidenced deviation from the original intended meaning for one item. The readability for English and Spanish versions was also assessed. Screening for elder abuse, if implemented systematically can be instrumental in identifying unrecognized abuse and preventing reoccurrence.     

Security-voting structure and equity financing in the banking sector: ‘one head-one vote’ versus ‘one share-one vote’

Using a unique dataset including all rights issues of new shares and other equity-like securities announced by Italian listed banks between 1989 and 2014, and exploiting the ideal setting provided by the Italian Banking Law, which allows for listed co-operative banks, we test if the ‘one head-one vote’ principle of co-operative banks and the ‘one share-one vote’ voting system of joint stock banks imply different costs of equity. Our empirical results, obtained using an event-study methodology, regressions and matching estimators, support our research hypothesis that the one head-one vote principle makes it more difficult raising new capital compared to one share-one vote principle, and contribute to the literature on demutualization and cooperative hybrids.

     

Anonymizing binary and small tables is hard to approximate

The problem of publishing personal data without giving up privacy is becoming increasingly important. An interesting formalization recently proposed is the k-anonymity. This approach requires that the rows in a table are clustered in sets of size at least k and that all the rows in a cluster become the same tuple, after the suppression of some records. The natural optimization problem, where the goal is to minimize the number of suppressed entries, is known to be NP-hard when the values are over a ternary alphabet, k=3 and the rows length is unbounded. In this paper we give a lower bound on the approximation factor that any polynomial-time algorithm can achieve on two restrictions of the problem, namely (i) when the records values are over a binary alphabet and k=3, and (ii) when the records have length at most 8 and k=4, showing that these restrictions of the problem are APX-hard.