43 research outputs found

    Decentralized subcontractor scheduling with divisible jobs

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    Subcontracting allows manufacturer agents to reduce completion times of their jobs and thus obtain savings. This paper addresses the coordination of decentralized scheduling systems with a single subcontractor and several agents having divisible jobs. Assuming complete information, we design parametric pricing schemes that strongly coordinate this decentralized system, i.e., the agents’ choices of subcontracting intervals always result in efficient schedules. The subcontractor’s revenue under the pricing schemes depends on a single parameter which can be chosen to make the revenue as close to the total savings as required. Also, we give a lower bound on the subcontractor’s revenue for any coordinating pricing scheme. Allowing private information about processing times, we prove that the pivotal mechanism is coordinating, i.e., agents are better off by reporting their true processing times, and by participating in the subcontracting. We show that the subcontractor’s maximum revenue with any coordinating mechanism under private information equals the lower bound of that with coordinating pricing schemes under complete information. Finally, we address the asymmetric case where agents obtain savings at different rates per unit reduction in completion times. We show that coordinating pricing schemes do not always exist in this case

    Production of biogas - a manner of manufacturing

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    Advertising is commonly criticised for being pervasive, offensive, manipulative, harmful and irresponsible. This thesis focuses on the subjective criticisms and complex issues related to taste, decency, morality and offence, particularly as applied to, and understood within, the public and non-profit contexts. It is positioned at the intersection of marketing communications, marketing ethics, and social and non-profit marketing and explores how shocking, offensive and/or controversial (SOC) advertising appeals are interpreted, regulated and contested, by divergent groups of people. The approach taken is inspired by stakeholder theory and its focus on ethical decision-making for the betterment of all stakeholders. A mixed methods research design was adopted, resulting in three studies and these are presented as three discrete articles. Article I maps the field of existing research into SOC advertising and identifies gaps in our knowledge by means of a systematic literature review. It offers a critical appraisal of the field by highlighting definitional tensions, limited interdisciplinary work and an overdependence on student samples, on quantitative analysis and on non-longitudinal methodologies. It then proposes a series of remedies to these shortcomings. The second and third papers continue this reparative work by conceptualising and analysing actual SOC advertising interpretations and contestations. Article II explores the interpretations and experiences of SOC advertising within the regulatory context by analysing evidence from complainants, advertisers and regulatory bodies. It then proposes and develops an interpretation of the implicit power dynamics through which their contradictory interests overlap. The methodology underpinning this chapter combines a thematic content analysis of a substantial archive of complaints submitted to the Advertising Standards Authority (ASA) with an interpretation of case adjudication reports influenced by the work of Michel Foucault. The findings suggest that the regulation of SOC advertising prioritises the interests of firms and advertisers by relegating the role of complainant to that of merely registering complaints. The focus of Article III moves from the regulatory framework to the complained-about advertisements themselves. It provides an innovative theoretical and methodological approach to analysing SOC advertisements, rooted in the classic Aristotelian notion of rhetorical appeals and figuration, by developing and analysing a carefully selected example in detail. The analysis reveals an implicit NFP sector-specific appeal to ethos and the importance of a complex appeal to pathos. Each of the papers offers a different level of analysis of the often-contradictory viewpoints represented by stakeholder groups involved in, or affected by, the use of SOC advertising tactics. These viewpoints include academics, general consumers, the vocal minority of complainants, the advertisers including the non-profit and public organisations and the advertising creatives, and the advertising regulator. Taken together, the papers amount to a thesis that makes an important contribution to debates about the appropriateness, ethics, and application of SOC themes, formats and imagery in social and non-profit advertising. By exploring the regulatory processes of the ASA, an exemplary advertising self-regulatory body, it further contributes to the discourse on self-regulatory practices and highlights an NFP sector-specific consequentialist approach that appears to stifle the voice of the offended complainant. On a practical level, this work has implications for advertising practitioners and advertising regulators who are involved in producing and regulating advertising that uses SOC tactics

    Significant release of shear energy of the North Korean nuclear test on February 12, 2013

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    On February 12, 2013 the Democratic People\u27s Republic of Korea (DPRK) carried out an announced nuclear test, which was the third after tests conducted in 2006 and 2009. An important task in discriminating a man-made explosion and a natural tectonic earthquake is the analysis of seismic waveforms. To determine the isotropic and non-isotropic characteristics of the detonation source, I invert long-period seismic data for the full seismic moment tensor to match the observed seismic signals by synthetic waveforms based on a 3D earth model. Here, I show that the inversion of long-period seismic data of the 2013 test reveals a clear explosive (isotropic) component combined with a significant release of shear energy by the double-couple part of the moment tensor. While the isotropic part of the nuclear test in 2009 was similar to that in 2013, the double-couple part was lower by a factor of 0.55 compared to the explosion in 2013. Moreover, the ratio of the isotropic seismic moments of the 2013 and 2009 nuclear tests is 1.4±0.1 and lower than published estimations of the yield ratio, which indicates the importance of considering the release of shear energy. The determined orientation of the double-couple fault plane is parallel to the dominating geologic fault structures NNE-SSW to NE-SW, but the calculated normal faulting mechanism does not correspond to the general tectonic strike-slip regime. Thus, explanations for the enhanced release of shear energy might be induced dip-slip motion pre-stressed by the previous test or near source damaging effects due to a changed containment of the nuclear explosion

    Uncertainty of moment tensor determination from surface wave analysis for shallow earthquakes

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    International audienceWe treat the problem of the non-uniqueness of the moment tensor inversion for shallow earthquakes from long period surface wave data. We give an existence condition for double couples radiating the same long period surface waves as the deviatoric moment tensor obtained by such inversion. We describe the family of such double couples and show that they may provide better estimates of double couple mechanisms than the traditional “best double-couple” solution. We demonstrate the results of application to four large shallow earthquakes with different source signatures

    Surface wave focusing effects: Numerical modeling and statistical observations

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    Most techniques used in seismological practice have been performed under the assumption that surface waves propagate along great circle arcs between the epicenter and the station. However, lateral variations of surface wave phase velocities should result in deviation of the wave paths from great circle arcs and in corresponding anomalies of geometrical spreading (so-called focusing effect). We performed numerical modeling of these effects using the ray approximation on the basis of recent global phase velocity maps for fundamental Rayleigh mode obtained by tomographic inversion in the period range from 60 to 150 s. The aim for such a modeling is to investigate where the conventional methods based on using great circles as paths fail, and to obtain quantitative characteristics for the effects of rays focusing. Predicted and observed focusing effects are analyzed from a statistical point of view on a dataset of real seismic data. Records of earthquakes in a wide magnitude range (6 < Ms < 7) and with epicenters in different seismic regions are used for the analysis (over 3000 measurements). Synthetic and observed Rayleigh wave amplitude spectra are found to be in better agreement when the focusing effect is taken into account: correction of spectra for predicted focusing effect significantly improves the fit of synthetics to observations at periods larger than 75 s. Calculation of focusing effect based on ray theory ignores the effects of wavefront smoothing which increases with increasing period. However, even this approximation gives considerable improvement of synthetics at periods up to 150 s and, therefore, can be used in many applications, such as seismic source studies, magnitude measurements, and Q estimates. We also demonstrated that the discrepancy between real data and synthetics cannot be explained by attenuation effects. It means that there is still large room for improvement of the existing tomographic models which, in order to correctly explain observed amplitudes, must include heterogeneity of anisotropy and anelasticity up to higher degree

    Long-period spectral features of the Sumatra-Andaman 2004 earthquake rupture process

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    The goal of this study is to investigate the spatial variability of the seismic radiation spectral content of the Sumatra\u2013Andaman 2004 earthquake. We determine the integral estimates of source geometry, duration and rupture propagation given by the stress glut moments of total degree 2 of different source models. These models are constructed from a single or a joint use of different observations including seismology, geodesy, altimetry and tide gauge data. The comparative analysis shows coherency among the different models and no strong contradictions are found between the integral estimates of geodetic and altimetric models, and those retrieved from very long period seismic records (up to 2000\u20133000 s). The comparison between these results and the integral estimates derived from observed surface wave spectra in period band from 500 to 650 s suggests that the northern part of the fault (to the north of 8\u25e6N near Nicobar Islands) did not radiate long period seismic waves, that is, period shorter than 650 s at least. This conclusion is consistent with the existing composite short and long rise time tsunami model: with short rise time of slip in the southern part of the fault and very long rise time of slip at the northern part. This complex space-time slip evolution can be reproduced by a simple dynamic model of the rupture assuming a crude phenomenological mechanical behaviour of the rupture interface at the fault scales combining an effective slip-controlled exponential weakening effect, related to possible friction and damage breakdown processes of the fault zone, and an effective linear viscous strengthening effect, related to possible interface lubrication processes. While the rupture front speed remains unperturbed with initial short slip duration, a slow creep wave propagates behind the rupture front in the case of viscous effects accounting for the long slip duration and the radiation characteristics in the northern segment

    Characterizing the foreshock, main shock, and aftershock sequences of the recent major earthquakes in Southern Alaska, 2016–2018

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    International audienceFor each of three major M≥7.0 earthquakes (i.e., the 24 January 2016, M7.1 earthquake 86 km E of Old Iliamna, the 23 January 2018, M7.9 earthquake 280 km SE of Kodiak, and the 30 November 2018, M7.1 earthquake 14km NNW of Anchorage, Alaska) the study considers integral characterization of the foreshock and aftershock sequences in terms of their variations and scaling properties including the behavior of the control parameter η of the unified scaling law for earthquakes (USLE), along with a detailed analysis of the surface wave records for reconstruction of the source in the approximation of the second moments of the stress glut tensor to obtain integral estimates of its length, orientation, and development over time. The three major earthquakes at 600 km around Anchorage are, in fact, very different due to apparent complexity of seismic dynamics in the orogenic corner of the Pacific and North America plate boundary. USLE generalizes the classic Gutenberg-Richter relationship taking into account the self-similar scaling of the empirical distribution of earthquake epicenters. The study confirms the existence of the long-term periods of regional stability of the USLE control parameter that are interrupted by mid- or even short-term bursts of activity associated with major catastrophic events

    Source parameters and tectonic origin of the 1996 June 1 Tianzhu (M<SUB>w</SUB>=5.2) and 1995 July 21 Yongden (M<SUB>w</SUB>=5.6) earthquakes near the Haiyuan fault (Gansu, China)

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    International audienceThe 1996 June 1 Tianzhu (Mw=5.2, Ms=4.9) and the 1995 July 21 Yongden (Mw=5.6, Ms=5.4) earthquakes are the two largest events recorded in the last 10 years between the 1990 October 20 Ms=5.8 and the recent 2000 June 6 Ms=5.6 earthquakes near the `Tianzhu seismic gap' on the Haiyuan fault in northeastern Tibet. We use frequency-time analysis (FTAN) to extract the fundamental modes of Love and Rayleigh waves from digital records. A joint inversion of their amplitude spectra and of P-wave first-motion polarities is then performed to calculate the source parameters (focal mechanisms, depths and seismic moments) of these two Ms~=5 earthquakes. Such a joint inversion is tested for the first time. We use IRIS and GEOSCOPE network records for period ranges of 20-40s for the former event and 35-70s for the latter. The inversion of the Tianzhu earthquake yields nodal planes with strike, dip and slip of 282°, 72° and 3° and 191°, 87° and 162°, respectively, a focal depth around 12km and a seismic moment of 0.56×1017Nm, consistent with the Harvard CMT calculation, and the alignment and depths of the aftershocks recorded by a local network. We propose two possible tectonic interpretations for this off-fault event. The solution for the Yongden earthquake is consistent with a thrust, with strike, dip and slip of 105°, 45° and 75°, respectively, a focal depth around 6km and a seismic moment of 2.4×1017Nm, also in agreement with the Harvard CMT mechanism, the distribution of the aftershocks recorded by a regional network, and the general tectonic setting that we refine
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