Knowledge integration via the fusion of the data models used in automotive production systems

ABSTRACT

In this paper a novel information model that can be used in Manufacturing Execution Systems is presented. The model is based on the fusion of ISA95, AML and OPC UA. ISA95 is used to define, unify and describe the details of a product and production technology. It also enables communication with ERP systems. The AML standard allows information about the production facilities to be presented. The OPC UA address space represents different parts of an information model while the OPC communication protocol enables it to be linked to actual production systems. The proposed concept is illustrated using an actual example of a production line for electronic devices.     

The political economy of redistribution under democracy

We ask what redistributions of income and assets are feasible in a democracy, given the initial assets and their distribution. The question is motivated by the possibility that if redistribution is insufficient for the poor or excessive for the rich, they may turn against democracy. In turn, if no redistribution simultaneously satisfies the poor and the wealthy, democracy cannot be sustained. Hence, the corollary question concerns the conditions under which democracy is sustainable. We find that democracies survive in wealthy societies. Conditional on the initial income distribution and the capacity of the poor and the wealthy to overthrow democracy, each country has a threshold of capital stock above which democracy survives. This threshold is lower when the distribution of initial endowments is more equal and when the revolutionary prowess of these groups is lower. Yet in poor unequal countries there exist no redistribution scheme which would be accepted both by the poor and the wealthy. Hence, democracy cannot survive. As endowments increase, redistribution schemes that satisfy both the poor and the wealthy emerge. Moreover, as capital stock grows the wealthy tolerate more and the poor less redistribution, so that the set of feasible redistributions becomes larger. Since the median voter prefers one such scheme to the dictatorship of either group, democracy survives.We would like to thank, Daron Acemoglu, Marco Basetto, Alberto Bisin, V.V. Chari, Pat Kehoe, Onur Ozgur for very useful comments.     

Incentive Fees and Mutual Funds

This paper examines the effect of incentive fees on the behavior of mutual fund managers. Funds with incentive fees exhibit positive stock selection ability, but a beta less than one results in funds not earning positive fees. From an investor's perspective, positive alphas plus lower expense ratios make incentive-fee funds attractive. However, incentive-fee funds take on more risk than non-incentive-fee funds, and they increase risk after a period of poor performance. Incentive fees are useful marketing tools, since more new cash flows go into incentive-fee funds than into non-incentive-fee funds, ceteris paribus.     

Longevity Bonds: Financial Engineering, Valuation, and Hedging

This article examines the main characteristics of longevity bonds (LBs) and shows that they can take a large variety of forms which can vary enormously in their sensitivities to longevity shocks. We examine different ways of financially engineering LBs and consider problems arising from the dearth of ultra‐long government bonds and the choice of the reference population index. The article also looks at valuation issues in an incomplete markets context and finishes with an examination of how LBs can be used as a risk management tool for hedging longevity risks.     

The moments of the Gompertz distribution and maximum likelihood estimation of its parameters

The Gompertz distribution is widely used to describe the distribution of adult deaths. Previous works concentrated on formulating approximate relationships to characterise it. However, using the generalised integro-exponential function, exact formulas can be derived for its moment-generating function and central moments. Based on the exact central moments, higher accuracy approximations can be defined for them. In demographic or actuarial applications, maximum likelihood estimation is often used to determine the parameters of the Gompertz distribution. By solving the maximum likelihood estimates analytically, the dimension of the optimisation problem can be reduced to one both in the case of discrete and continuous data. Monte Carlo experiments show that by ML estimation, higher accuracy estimates can be acquired than by the method of moments.     

On a general periodic preventive maintenance policy incorporating warranty contracts and system ageing losses

In this paper, a general periodic preventive maintenance (PM) policy for a repairable revenue-generating system is developed and studied. We define ‘ageing losses’ as the difference in revenues generated by an ideal system (no ageing) and a real system that ages over the same period of consideration. It is assumed that preventive maintenance slows the system deterioration process and therefore reduces ageing losses. The proposed model is general in the sense that (1) both the warranty contracts and system ageing losses are incorporated in the maintenance cost modeling and (2) the implementation of PM actions does not have to be strictly periodic. A cost model is developed for the buyer under two decision variables—the calendar time of the first PM and the degree of each PM. Numerical examples are then presented to show the effectiveness of the proposed model. Sensitivity analyses are further conducted to investigate the impact of model parameters on optimal solutions.     

Enhancing television advertising: same-language subtitles can improve brand recall,verbal memory,and behavioral intent

This research explores how same-language subtitles—on-screen text that matches the spoken language—can enhance advertising effectiveness for television commercials on normal viewing audiences outside of foreign-language or deaf-viewer contexts. A preliminary eye-tracker study shows that same-language subtitles capture disproportionate visual attention, and a first study highlights that same-language commercial subtitles can increase brand recall and memory of other verbal ad information. Three further studies using 12 additional ads reinforce the positive effects of subtitles and show how same-language subtitle effectiveness varies with changes in visual and verbal ad complexity. In addition to showing how subtitles can increase behavioral intent, results also highlight how varying subtitle content affects memory gains and illustrate how subtitles can lead to negative effects in the uncommon situation that brand information is missing from the audio. As the efficacy of television advertising becomes increasingly debated, same-language subtitling is a simple way to boost advertising effectiveness.     

Assessing self-selection and endogeneity issues in the relation between activity-based costing and performance

Studies investigating the relation between ABC adoption and performance are inconclusive and plagued with econometric problems. This study extends prior research to investigate the association between ABC adoption and four manufacturing plant performance measures (cycle-time improvement, quality improvement, cost improvement, and profitability) and to assess selection bias and the endogenous nature of their relationship. I use the Heckman (1979) model to assess sample selection bias and the Wooldridge (2002) 2SLS-IV approach, to investigate endogeneity. After controlling for sample selection bias and endogeneity, the coefficient of ABC under the Heckman method and ABC_fit under the 2SLS-IV method becomes significantly higher compared to the coefficient of ABC under the OLS method. In addition, both the inverse Mills ratio, under the Heckman model, and Hausman F-test, under the Wooldridge 2SLS approach, are positive and significant, confirming the presence of both sample selection bias and endogeneity. Overall, I find that controlling for sample selection bias and endogeneity is essential in properly assessing the significance of ABC-performance association.