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International audience; An optimal layout configuration has considerable impacts on industrial engineering. The conventional layout problem aims to find the optimal arrangement of components inside the container while satisfying no component overlap and no container protrusion constraints. In this paper, we address accessibility requirements in layout problems. The novel layout model consists of components with solid and virtual parts. On the one hand, virtual spaces associated with solid components represents the accessibility of component. On the other hand, characterizing accessibility as a constraint ensures components are accessible from the container's entry. The industrial layout involves various objectives and is usually formulated as a multi-objective problem. Hence, a novel multiobjective layout optimization using constructive placement and simulated annealing, named constructive optimization, is developed. A complete layout is generated by constructive placement and evaluated by simulated annealing. It only explores the feasible space and greatly reduces the computational effort. The experimental results prove that the constructive optimization method is effective in solving the problem of industrial layout.

International audience; The conventional layout problem is concerned with finding the arrangements of components inside the container to optimize objectives under geometrical constraints, i.e., no component overlap and no container protrusion. In this paper, the multi-objective optimization for layout balance and component activity requirements with functional constraints is developed. Integrating the accessibility of components as functional constraints ensures components maintenance or proper operation. However, addressing the functional constraints increase the complexity of the layout optimization. A novel multi-objective optimization algorithm is proposed using the constructive placement and the simulated annealing to search for compromised solutions between the two objectives. Thereafter, a similarity indicator is defined to evaluate how similar optimized layout designs are. The experiments indicate that the proposed optimization approach performs well in ensuring accessibility and efficiently finding high-qualified solutions, where the constructive placement largely contributes to the search for alternatives satisfying constraints.

International audience; This paper presents an efficient simulated annealing algorithm for solving multi-objective layout problems where several rectangular components are placed, respecting non-overlap and non-protrusion constraints in the given space. Resolving layout problems can be very hard in some industrial cases because problems are over-constrained and computing feasible optimal layout designs are time consuming. In most practical problems, both real and virtual components exist. The virtual components represent the required accessible space allowing the user to access to the component. The virtual components can overlap with each other, while the overlap is not allowed for the real components. Considering the limited layout design space, the capacity of the layout problem is analyzed using constructive placing techniques. To explore the feasible layout space, a hybrid simulated annealing is proposed to determine the order of placement; then, a constructive placing strategy based on empty maximal space is developed. What’s more, an interactive visualization environment is introduced between the optimization and expert. The proposed algorithm is the first attempt to search feasible space of multi-objective layout design by constructive placing method.

Layout optimization plays an important role in the field of industrial engineering. The layout problem presented here involves the real and virtual rectangular components. The real components can be the devices or buildings depending on the application. The space of accessibility associated with the real component is virtual, which allows the user to access the real component in reality, such as facility maintenance. However, most of the layout problems are NP hard. The great complexity of layout problems increase the difficulty in finding a feasible layout design in a reasonable time. To resolve these problems, we propose a hybrid constructive placing strategy which makes the search of feasible designs easier. The multi-objective application presented in this study demonstrates the effectiveness and portability of the method. Since the number of optimal layout designs can be very large, a cluster approach is followed to group all similar solutions. First, the notion of pairwise similarity indicator is introduced to analyze the similarity among the optimized layout designs. Second, the visualization of the hierarchical clustering of similarity matrix is customized. Then for each design, the user can interact with it by locally modifying the position or rotation of the component. The interactivity helps the user evaluate performance of the designs and preferable results are typically achieved.

International audience; As a traditional tool of external assistance, crutches play an important role in society. They have a wide range of applications to help either the elderly and disabled to walk or to treat certain illnesses or for post-operative rehabilitation. But there are many different types of crutches, including shoulder crutches and elbow crutches. How to choose has become an issue that deserves to be debated. Because while crutches help people walk, they also have an impact on the body. Inappropriate choice of crutches or long-term misuse can lead to problems such as scoliosis. Previous studies were mainly experimental measurements or the construction of dynamic models to calculate the load on joints with crutches. These studies focus only on the level of the joints, ignoring the role that muscles play in this process. Although some also take into account the degree of muscle activation, there is still a lack of quantitative analysis. The traditional dynamic model can be used to calculate the load on each joint. However, due to the activation of the muscle, this situation only causes part of the load transmitted to the joint, and the work of the chair will compensate the other part of the load. Analysis at the muscle level allows a better understanding of the impact of crutches on the body. By comparing the levels of activation of the trunk muscles, it was found that the use of crutches for walking, especially a single crutch, can cause a large difference in the activation of the back muscles on the left and right sides, and this difference will cause muscle degeneration for a long time, leading to scoliosis. In this article taking scoliosis as an example, by analyzing the muscles around the spine, we can better understand the pathology and can better prevent diseases. The objective of this article is to analyze normal walking compared to walking with one or two crutches using OpenSim software to obtain the degree of activation of different muscles in order to analyze the impact of crutches on the body.

International audience; Electronic phased-array radars offer new possibilities for radar search pattern optimization by using bi-dimensional beam-forming and beam-steering. Radar search pattern optimization can be approximated as a set cover problem and solved using integer programming, while accounting for localized clutter and terrain masks in detection constraints. We present a set cover problem approximation for time-budget minimization of radar search patterns, under constraints of range, detection probability and direction-specific scan update rates. Branch&Bound is a classical optimization procedure for solving combinatorial problems. It is known mainly as an exact algorithm, but features interesting characteristics, making it particularly fit for solving optimization problems in real-time applications and producing just-in-time solutions.