Dummy Impact Research Articles

The effect of transitioning into temporary employment on wages is not negative: A comparative study in eight countries

There remains a lack of clarity about the effect of temporary employment on wages. Using asymmetric fixed effects models with a dummy impact function, we study the wage effects of four distinct transitions: (1) from unemployment into a temporary relative to (2) a permanent contracts; and (3) from temporary into permanent contracts relative to (4) from permanent into temporary contracts. We use panel data from eight countries to examine the effect of these distinct transitions, over time after the transition occurs, and in a cross-national, comparative context. The main finding explains the wage penalty of temporary employment identified by previous research. The negative effect is more accurately understood as the difference between two types of transitions, neither of which are negative, even if transitions from temporary into permanent contracts more positive than transitions from permanent into temporary contracts. There is little difference in the wage effect of transitions from unemployment into temporary relative to permanent contracts. The findings may be counter intuitive, but they are consistent with the theory of equalizing differences.

On the proper computation of Ad Valorem equivalent of non-tariff measures

ABSTRACT In all the previous studies evaluating the Ad Valorem Equivalent (AVE) of Non-Tariff Measures (NTMs) based on a gravity equation, Jensen’s inequality is not considered. Yet the issue of estimating the impact of dummy or count variables in semi-log or related equations has been raised since the early eighties. In this article, we illustrate the bias associated with the omission of Jensen’s inequality and show that when it is not considered, the estimation of AVEs can be significantly biased. This omission leads to a significant underestimation of the restrictive impact of NTMs and can even change the sign of the AVE.

Modelling head injury due to unmanned aircraft systems collision: Crash dummy vs human body

Recent developments in the concept of UAS operations in urban areas have led to risk concerns of UAS collision with human. To better understand this risk, head and neck injuries due to UAS collisions have been investigated by different research teams using crash dummies. Because of the limitations in biofidelity of a crash dummy, head injury level for a crash dummy impact may differ from the human body impact. Therefore, the aim of this paper is to investigate differences in head and neck injuries subject to UAS collision between an often-used Hybrid III crash dummy and a human body. To perform such investigation, multibody system (MBS) impact models have been used to simulate UAS impacts on validated models of the Hybrid III crash dummy and the human body at various impact conditions. The findings show that the Hybrid III predicts similar head and neck injury compared to the human body when UAS collides horizontally from front and rear. However, the Hybrid III over-predicts head injury due to horizontal side impact. Moreover, under vertical drop and 45 degree elevated impact of UAS, the Hybrid III under-predicts head injury, and over-predicts neck injury.

When and how does volunteering influence wages? – Evidence from panel data

Volunteering is an activity in which individuals work for free to benefit others; however, research has also focused on the benefits volunteers themselves might experience. We add to the literature by focusing on how not only volunteering itself has an impact on wages but how the intensity, duration and timing of volunteering also have an effect on these. In addition, we distinguish between the effects on volunteers in the same job and when changing a job, and test the role of social capital. Using German data from the Socio-Economic Panel, we find that current volunteering has positive effects on wages in a fixed effects wage regression, especially if individuals volunteer with low to medium intensity. The duration of volunteering does not increase wages. However, based on the dummy impact function, we find that volunteering increases wages almost immediately and that this effect remains fairly constant over time. We find no indication that reverse causality drives this effect. Furthermore, we show that the wage benefits of volunteering are realized only through job changes, not on-the-job wage progression. With regard to job changers, we show that social capital accumulation through volunteering is one reason explaining the observed wage effects.

Head injury of CHARM-70 FE model and a comparative study with Hybrid III and GHBMC model

In this paper, the Hybrid III FE head model is validated through dummy impact experiments firstly. Then, the CHARM-70 head model is developed, and the structure, head injury and dynamic mechanical response of the model are studied. Subsequently, the GHBMC head model is introduced to compare the dynamic mechanical response of the forehead to the steering wheel edge under the same speed with the Hybrid III and the CHARM-70. The result demonstrates that the CHARM-70 model has high biological fidelity. Meanwhile, due to different material properties, GHBMC model shows the best stiffness and force response, followed by CHARM-70 model, and finally Hybrid III model. Finally, the different setting of material parameters indicates a fine response to the decline rule of bone strength caused by human age, which is meaningful for the development of different age, body and other special population models in the future.

Head injury of CHARM-70 FE model and a comparative study with Hybrid III and GHBMC model

In this paper, the Hybrid III FE head model is validated through dummy impact experiments firstly. Then, the CHARM-70 head model is developed, and the structure, head injury and dynamic mechanical response of the model are studied. Subsequently, the GHBMC head model is introduced to compare the dynamic mechanical response of the forehead to the steering wheel edge under the same speed with the Hybrid III and the CHARM-70. The result demonstrates that the CHARM-70 model has high biological fidelity. Meanwhile, due to different material properties, GHBMC model shows the best stiffness and force response, followed by CHARM-70 model, and finally Hybrid III model. Finally, the different setting of material parameters indicates a fine response to the decline rule of bone strength caused by human age, which is meaningful for the development of different age, body and other special population models in the future.

Impact of dummy variables in a probabilistic competitive environment

Most of the competitive environments are highly dynamic in nature and also fragile. The active and inactive participation of competitors may prompt an improper decision making. The article focuses on the behaviour and impact of dummy (inactive) competitors in the system. The study is to generate a maxima or minima in a time-probability distribution of all competitors in terms of inactive competitors. The inefficiency of the discrete ranking model without frequency to generate a maxima or minima in the corresponding position-probability distribution and also the capability of continuous infinite model with frequency for the same purpose conferred. The necessary conditions on behalf of with and without dummy variable to create a peak or dip in the position- probability distribution through one tail and two tail addition in the competitor frequency distribution curve is additionally contemplated. The cutting edge e-SCM scenario comprising of fake rating and reviewing is regularly critical in e-Marketing. The summed up model examined here along these lines causes us to anticipate the probabilities for selling and the related risk factor required by thinking about the number of fake rating as a spurious variable in the framework. A case study has been incorporated to study the impact of dummy variable in the system. The model will definitely find application in decision making and strategic formation process in the various fields of quality and inspection engineering, economics and social sciences etc.