How the structure of precedence constraints may change the complexity class of scheduling problems

This survey aims at demonstrating that the structure of precedence constraints plays a tremendous role on the complexity of scheduling problems. Indeed many problems can be NP-hard when considering general precedence constraints, while they become polynomially solvable for particular precedence constraints. We also show that there still are many very exciting challenges in this research area

New complexity results for parallel identical machine scheduling problems with preemption, release dates and regular criteria

In this paper, we are interested in parallel identical machine scheduling problems with preemption and release dates in case of a regular criterion to be minimized. We show that solutions having a permutation flow shop structure are dominant if there exists an optimal solution with completion times scheduled in the same order as the release dates, or if there is no release date. We also prove that, for a subclass of these problems, the completion times of all jobs can be ordered in an optimal solution. Using these two results, we provide new results on polynomially solvable problems and hence refine the boundary between P and NP for these problems

A Note on NP-Hardness of Preemptive Mean Flow-Time Scheduling for Parallel Machines

In the paper "The complexity of mean flow time scheduling problems with release times", by Baptiste, Brucker, Chrobak, D\"urr, Kravchenko and Sourd, the authors claimed to prove strong NP-hardness of the scheduling problem $P|pmtn,r_j|\sum C_j$, namely multiprocessor preemptive scheduling where the objective is to minimize the mean flow time. We point out a serious error in their proof and give a new proof of strong NP-hardness for this problem

Recovering Beam Search Approach for the Multi-Skill Project Scheduling Problem

International audienc

New insights into the genetic etiology of Alzheimer’s disease and related dementias

Artículo escrito por un elevado número de autores, solo se referencia el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMCharacterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 alleleThis research was conducted using the UKBB resource (application number 61054). This work was funded by a grant (EADB) from the EU Joint Programme – Neurodegenerative Disease Research. INSERM UMR1167 is also funded by the INSERM, Institut Pasteur de Lille, Lille Métropole Communauté Urbaine and French government’s LABEX DISTALZ program (development of innovative strategies for a transdisciplinary approach to AD). Full consortium acknowledgements and funding are in the Supplementary Note

METHODS FOR THE SHIFT DESIGN AND PERSONNEL TASK SCHEDULING PROBLEM

Colloque avec actes et comité de lecture. internationale.International audienceThis paper introduces an overview of the methods that have been used in the literature to solve the Shift Design and Personnel Task Scheduling Problem with Equity. Basically, this problem aims at designing a schedule while assigning fixed tasks, that cannot be preempted, to an heterogeneous workforce. Such problem may occur in several contexts, where industrial activity requires a sharp and efficient management of workers. In this paper, we focus on the particular case of a company specialized in drug evaluation. This company is facing a scheduling problem that may be modelized as a Shift Design and Personnel Task Scheduling Problem with Equity. Based on realistic instances of this particular problem, we compare the relative performances of the different methods considered: A two-phase method, a constraint-based approach and a large neighborhood search derived from the constraint-based model

A two-phase method for the Shift Design and Personnel Task Scheduling Problem with Equity objective

International audienceIn this paper, we study the Shift Design and Personnel Task Scheduling Problem with Equity objective (SDPTSP-E), initially introduced in [11]. This problem consists in designing the shifts of workers and assigning a set of tasks to quali ed workers, so as to maximise the equity between workers. We propose a natural two-phase approach consisting in rst designing shifts and then assigning tasks to workers, and we iterate between these two phases to improve solutions. We compare our experimental results with existing literature and show that our approach outperforms previous known results