Advanced production scheduling for batch plants in process industries

An Advanced Planning System (APS) offers support at all planning levels along the supply chain while observing limited resources. We consider an APS for process industries (e.g. chemical and pharmaceutical industries) consisting of the modules network design (for long–term decisions), supply network planning (for medium–term decisions), and detailed production scheduling (for short–term decisions). For each module, we outline the decision problem, discuss the specifi cs of process industries, and review state–of–the–art solution approaches. For the module detailed production scheduling, a new solution approach is proposed in the case of batch production, which can solve much larger practical problems than the methods known thus far. The new approach decomposes detailed production scheduling for batch production into batching and batch scheduling. The batching problem converts the primary requirements for products into individual batches, where the work load is to be minimized. We formulate the batching problem as a nonlinear mixed–integer program and transform it into a linear mixed–binary program of moderate size, which can be solved by standard software. The batch scheduling problem allocates the batches to scarce resources such as processing units, workers, and intermediate storage facilities, where some regular objective function like the makespan is to be minimized. The batch scheduling problem is modelled as a resource–constrained project scheduling problem, which can be solved by an efficient truncated branch–and–bound algorithm developed recently. The performance of the new solution procedures for batching and batch scheduling is demonstrated by solving several instances of a case study from process industries.

The New Concept of Universal Service in a Digital Networked Communications Environment

Digitization, sophisticated fiber-optic networks and the resultant convergence of the media, communications and information technology industries have completely transformed the communications ecosystem in the last couple of decades. New contingent business and social models were created that have been mirrored in the amended communications regimes. Yet, despite an overhaul of the communications regulation paradigm, the status of and the rules on universal service have remained surprisingly intact, both during and after the liberalization exercise. The present paper looks into this paradox and examines the sustainability of the existing concept of universal service. It suggests that there is a need for a novel concept of universal service in the digital networked communications environment, whose objectives go beyond the conventional internalizing and redistributional rationales and concentrate on communication and information networks as a public good, where not only access to infrastructure but also access to content may be essential.

Superorganism resilience: eusociality and susceptibility of ecosystem service providing insects to stressors

Insects provide crucial ecosystem services for human food security and maintenance of biodiversity. Therefore, major declines in wild insects combined with losses of managed bees have raised great concern. Recent data suggest that honey bees appear to be less susceptible to stressors compared to other species. Here, we argue that eusociality plays a key role for the susceptibility of insects to environmental stressors due to superorganism resilience, which can be defined as the ability to tolerate the loss of somatic cells (= workers) as long as the germ line (= reproduction) is maintained. Life history and colony size appear critical for such resilience. Future conservation efforts should take superorganism resilience into account to safeguard ecosystem services by insects.