The Evolution of Subsea Wells Plug and Abandon by the Use of Intervention Vessel

During the last years, the total number of subsea wells considerably increased thanks to growing investments in the development of deep and ultra-deep water fields. At the end of their producing life, all these wells will need to be decommissioned and permanently plugged and abandoned, so the demand for technologies that will allow to fulfil this task in the respect of the regulations and at the minimum cost gained a lot of momentum. This paper describes a permanent P&A strategy of subsea wells to be carried out with Well Intervention vessel. The study first goes through the operation sequence and available technologies, defining an abandonment approach which is in line with international standards. Identified strategy results into a significant time and cost reduction comparing with traditional subsea wells decommissioning works performed by a floater rig, even maintaining the same level of safety and effectiveness. The study shows that the overall time reduction estimated by using an intervention vessel ranges from 40 to 55%, compared to a conventional rig-based approach, leading the wells abandonment expenditure savings up to 70%. For all those wells where the implementation of an intervention vessel is not guaranteed, there is still room to get time and cost savings of about 5-15% by combining the same riserless technologies with a conventional floater rig.

Reactive Scheduling Based on Adaptive Manipulator Operations in a Job Shop Configuration with Two Machines

Manufacturing systems are affected by uncertainties, such as machine failure or tool breakage, which result in system downtime and productivity deterioration. In machining processes, system downtime must be reduces. This study aims to establish an automated scheduling technique that flexibly responds to unforeseen events, such as machine failure, based on adaptive operations of the handling manipulator instead of an operation schedule for the machine tools. We propose an “adaptive manipulation” procedure for establishing a reactive revision policy. The reactive revision policy modifies a portion of the manipulator operation sequence, followed by the machine operation sequence. We conduct a physical scheduling simulation on a material-handling manipulator system imitating a job-shop manufacturing system. Through simulations involving machine breakdown scenarios, the applicability of the reactive revision policy based on adaptive manipulation is demonstrated.

Model and algorithm for the first-level maintenance operation optimization of EMU trains

As a key operation for the daily maintenance of electric multiple units (EMU), the first-level maintenance operation directly affects the utilization efficiency of the EMU. The fixed operation sequence of EMU trains, the limitation of the track capacity and inconsistent arrival time of EMU trains give rise to such problems as extended waiting time, idle tracks and waste of maintenance capacity. To solve these problems and optimize the assignment of EMU-to-track, we propose a flexible job-shop sequence scheduling (Flexible-JSS) mode for the first-level maintenance of EMU trains, and a flexible sequence and tracks sharing (FSTS) model for the first-level maintenance at electric multiple units depot (EMUD) has also been proposed in this paper. The FSTS model is designed to shorten the latest completion time after taking into account the constraints such as the train length, track capacity, the operation sequence of all EMU trains, the operation process of a single EMU train, and the train-set scheduling plan. A modified genetic algorithm is used to solve the model. The feasibility and effectiveness of the model and algorithm are verified by a real case, and the comparison with the other two fixed job-shop sequence scheduling (Fixed-JSS) modes proves that the Flexible-JSS mode can improve the efficiency and ability of the first-level maintenance at EMUD impressively.

Picture Preview Generation for Interactive Educational Resources

With the development of network technology, many online educational resource platforms have emerged, and the number of resources on these platforms is increasing dramatically. Compared with the traditional resources, the interactive educational resources (IERs) have hidden interactive information and dynamic content. Only when the users perform interactive operations correctly can they acquire the knowledge conveyed by the resources, which makes it a challenge to help the users understand the general content of resources and find the resources that they are interested in. Therefore, in this paper, we propose a method for generating picture previews of IERs. Firstly, we analyze the file that stores interactive resource information, obtain the interactive elements’ information, extract the dependencies, and generate an operation sequence. Secondly, we execute the operation sequence using an automated software tool to mimic the interaction process between the user and the resource and save the screenshots in the process to generate a picture preview of an IER. We apply this method to a dynamic geometry platform, NetPad, and conduct experiments. Experimental results demonstrate that the method can effectively extract interactive semantic information and simulate the interactive process, and the generated picture previews are of great help to the users to understand the content of IERs.

The digital platform of the future school: the digital-cognitive approach against the digital-algorithmic reduction of educational practice

The paper differentiates two approaches to digitalization of the educational practice: the digital-algorithmic approach and the digital-cognitive approach. The digital-algorithmic approach puts in correspondence pupil’s answer with described and established rules and operations to achieve “correct” responses. Application of the first approach forces students to guess right operation sequence to find the right solution. The digital-cognitive approach provides a background for modeling, visualizing and making representation of thinking acts and action for school students and teacher. Realization of the second approach aims to organize the digital educational milieu of the new generation. This the digital educational milieu supports and stimulates student work to find types of operations, the operation set and the operation sequence according to student’s understanding of the problem and grasping the situation. The model of the thinking act that is elaborated by Vasiliy Davydov as the “cell” for the interdisciplinary theory of thought processes is considered to be the core for constructing a digital educational milieu of the new generation. Described forms of thinking act with increasing complexity provides organization of digital-cognitive systems in education.