Lean Construction in Supply Chain Management： Supplier and Buyer Relationship in Social Housing

To the accomplishment of this article, we have chosen, as a case study, a small Goiana construction company that acted in the market of social housing. The main goal of this work is to analyze the fundamental aspects related to the management of the flow of supplies in civil construction to achieve a greater streamlining of logistic processes involved in supplying material. A checklist was developed for the purpose of data collection, and it was applied by means of an interview with the person in charge of the purchase department of the enterprise. In addition, this person is the engineer of the site. Taking into account the exploratory feature of this research, the construction site was visited so that some issues, such as quality aspects, losses, cleanliness and organization, could be observed. This on-site data collection visit was carried out through visual analyses and photographs. The obtained results were subdivided into a quantitative and a qualitative analysis. In this way, it was possible to see that the production process still has many phases to be improved. What is more, it was possible to see that the construction company knows its flaws and necessities to improve its processes although the final result does not have the expected quality. Being aware of this need for improvement, the construction company aims at having an affordable price product to the target public, especially when it is associated to an image that shows quality.

Dynamic Event-triggered Control and Estimation: A Survey

The efficient utilization of computation and communication resources became a critical design issue in a wide range of networked systems due to the finite computation and processing capabilities of system components(e.g., sensor, controller) and shared network bandwidth. Event-triggered mechanisms(ETMs) are regarded as a major paradigm shift in resource-constrained applications compared to the classical time-triggered mechanisms, which allows a trade-off to be achieved between desired control/estimation performance and improved resource efficiency. In recent years, dynamic event-triggered mechanisms(DETMs) are emerging as a promising enabler to fulfill more resource-efficient and flexible design requirements. This paper provides a comprehensive review of the latest developments in dynamic event-triggered control and estimation for networked systems. Firstly, a unified event-triggered control and estimation framework is established, which empowers several fundamental issues associated with the construction and implementation of the desired ETM and controller/estimator to be systematically investigated. Secondly, the motivations of DETMs and their main features and benefits are outlined. Then, two typical classes of DETMs based on auxiliary dynamic variables(ADVs) and dynamic threshold parameters(DTPs) are elaborated. In addition, the main techniques of constructing ADVs and DTPs are classified, and their corresponding analysis and design methods are discussed. Furthermore, three application examples are provided to evaluate different ETMs and verify how and under what conditions DETMs are superior to their static and periodic counterparts. Finally, several challenging issues are envisioned to direct the future research.