Multi-objective integer programming: A general approach for generating all nondominated solutions

In this paper we develop a general approach to generate all non-dominated solutions of the multi-objective integer programming (MOIP) Problem. Our approach, which is based on the identification of objective efficiency ranges, is an improvement over classical e-constraint method. Objective efficiency ranges are identified by solving simpler MOIP problems with fewer objectives. We first provide the classical e-constraint method on the bi-objective integer programming problem for the sake of completeness and comment on its efficiency. Then present our method on tri-objective integer programming problem and then extend it to the general MOIP problem with k objectives. A numerical example considering tri-objective assignment problem is also provided

Rescheduling unrelated parallel machines with total flow time and total disruption cost criteria

In this paper, we consider a rescheduling problem where a set of jobs has already been assigned to unrelated parallel machines. When a disruption occurs on one of the machines, the affected jobs are rescheduled, considering the efficiency and the schedule deviation measures. The efficiency measure is the total flow time, and the schedule deviation measure is the total disruption cost caused by the differences between the initial and current schedules. We provide polynomial-time solution methods to the following hierarchical optimization problems: minimizing total disruption cost among the minimum total flow time schedules and minimizing total flow time among the minimum total disruption cost schedules. We propose exponentialtime algorithms to generate all efficient solutions and to minimize a specified function of the measures. Our extensive computational tests on large size problem instances have revealed that our optimization algorithm finds the best solution by generating only a small portion of all efficient solutions

Generating all efficient solutions of a rescheduling problem on unrelated parallel machines

In this paper, we consider a rescheduling problem where a set of jobs has already been assigned to unrelated parallel machines. When a disruption occurs on one of the machines, the affected jobs are rescheduled, considering the efficiency and stability measures. Our efficiency measure is the total flow time and stability measure is the total reassignment cost caused by the differences in the machine allocations in the initial and new schedules. We propose a branch and bound algorithm to generate all efficient solutions with respect to our efficiency and stability measures. We improve the efficiency of the algorithm by incorporating powerful reduction and bounding mechanisms. Our computational tests on large sized problem instances have revealed the satisfactory behaviour of our algorithm

Bicriteria multiresource generalized assignment problem

In this study,we consider a bicriteria multiresource generalized assignment problem. Our criteria are the total assignment load and maximum assignment load over all agents. We aim to generate all nondominated objective vectors and the corresponding efficient solutions. We propose several lower and upper bounds and use them in our optimization and heuristic algorithms. The computational results have shown the satisfactory behaviors of our approaches. © 2014 Wiley Periodicals, Inc

Equilibrium Formation of Stable All‐Silicon Versions of 1,3‐Cyclobutanediyl

Main group analogues of cyclobutane‐1,3‐diyls are fascinating due to their unique reactivity and electronic properties. So far only heteronuclear examples have been isolated. Here we report the isolation and characterization of all‐silicon 1,3‐cyclobutanediyls as stable closed‐shell singlet species from the reversible reactions of cyclotrisilene c ‐Si3Tip4 (Tip=2,4,6‐triisopropylphenyl) with the N‐heterocyclic silylenes c ‐[(CR2CH2)(Nt Bu)2]Si: (R=H or methyl) with saturated backbones. At elevated temperatures, tetrasilacyclobutenes are obtained from these equilibrium mixtures. The corresponding reaction with the unsaturated N‐heterocyclic silylene c ‐(CH)2(Nt Bu)2Si: proceeds directly to the corresponding tetrasilacyclobutene without detection of the assumed 1,3‐cyclobutanediyl intermediate

Bildung Stabiler All‐Silicium Varianten von 1,3‐Cyclobutandiyl im Gleichgewicht

Hauptgruppenanaloga von 1,3‐Cyclobutandiylen faszinieren mit ihrer einzigartigen Reaktivität und ihren elektronischen Eigenschaften. Bisher sind allerdings nur heteronukleare Vertreter isoliert worden. Wir berichten hier über die Isolierung und Charakterisierung von All‐Silicium‐1,3‐Cyclobutandiylen als stabile Singulettspezies mit geschlossenschaliger Konfiguration aus den reversiblen Reaktionen von Cyclotrisilen c ‐Si3Tip4 (Tip=2,4,6‐Triisopropylphenyl) mit den N‐heterocyclischen Silylenen c ‐[(CR2CH2)(Nt Bu)2]Si: (R=H oder Methyl) mit gesättigten Grundgerüsten. Bei erhöhten Temperaturen werden aus diesen Gleichgewichtsmischungen Tetrasilacyclobutene erhalten. Die analoge Reaktion mit dem ungesättigten N‐heterocyclischen Silylen c ‐(CH)2(Nt Bu)2Si: verläuft direkt zum entsprechenden Tetrasilacyclobuten ohne Nachweis des angenommenen 1,3‐Cyclobutandiyl‐Zwischenprodukts

Identifying patient subgroups in the heterogeneous chronic pain population using cluster analysis

Chronic pain is an ill-defined disease with complex biopsychosocial aspects, posing treatment challenges. We hypothesized that treatment failure results, at least partly, from limited understanding of diverse patient subgroups. We aimed to identify subgroups using psychological variables, allowing for more tailored interventions. In a retrospective cohort study, we extracted patient-reported data from two Dutch tertiary multidisciplinary outpatient pain clinics (2018–2023) for unsupervised hierarchical clustering. Clusters were defined by anxiety, depression, pain catastrophizing, and kinesiophobia. Sociodemographics, pain characteristics, diagnosis, lifestyle, health-related quality of life and treatment efficacy were compared among clusters. A prediction model was built utilizing a minimum set of questions to reliably assess cluster allocation. Among 5466 patients with chronic pain, three clusters emerged. Cluster 1 (n=750) was characterized by high psychological burden, low health-related quality of life, lower educational levels and employment rates, and more smoking. Cluster 2 (n=1795) showed low psychological burden, intermediate health-related quality of life, higher educational levels and employment rates, and more alcohol consumption. Cluster 3 (n=2909) showed intermediate features. Pain reduction following treatment was least in cluster 1 (28.6% after capsaicin patch, 18.2% after multidisciplinary treatment), compared to &gt;50% for both treatments in clusters 2 and 3. A model incorporating 15 psychometric questions reliably predicted cluster allocation. In conclusion, our study identified distinct chronic pain patient clusters through 15 psychological questions, revealing one cluster with notably poorer response to conventional treatment. Our prediction model, integrated in a web-based tool, may help clinicians improve treatment by allowing patient-subgroup targeted therapy according to cluster allocation. Perspective: Hierarchical clustering of chronic pain patients identified three subgroups with similar pain intensity and diagnoses but distinct psychosocial traits. One group with higher psychological burden showed poorer treatment outcomes. A web-based tool using this model could help clinicians tailor therapies by matching interventions to specific patient subgroups for improved outcomes.</p

Rasip1-Mediated Rho GTPase Signaling Regulates Blood Vessel Tubulogenesis via Nonmuscle Myosin IINovelty and Significance

Vascular tubulogenesis is essential to cardiovascular development. Within initial vascular cords of endothelial cells (ECs), apical membranes are established and become cleared of cell-cell junctions, thereby allowing continuous central lumens to open. Rasip1 is required for apical junction clearance, as well as for regulation of Rho GTPase activity. However, it remains unknown how activities of different Rho GTPases are coordinated by Rasip1 to direct tubulogenesis

Autonomic dysfunction in gastroesophageal reflux disease. The neurogastro-cardiac axis: friend or foe?

Gastroesophageal reflux disease (GERD) is a complex and highly prevalent entity. Impaired gut-brain communication is associated with autonomic dysfunction. Modulation of the autonomic nervous system controls gastrointestinal functions. In GERD, a decrease in vagal tone (parasympathetic activity) and an increase in sympathetic activity with autonomic balance shifted towards the sympathetic system have been reported. Clinical questionnaires and non-invasive measurement of heart rate variability may be useful in patients with GERD to detect autonomic dysfunction. Restoration of parasympathetic system activity (mainly neuromodulation), with subsequent improvement of parasympathetic activity, will reduce the intensity of autonomic symptoms and GERD, improving quality of life. - La enfermedad por reflujo gastroesofágico (ERGE) es una condición compleja y altamente prevalente. El deterioro de la comunicación intestino-cerebro está asociado a la disfunción autonómica. La modulación del sistema nervioso autónomo controla las funciones gastrointestinales. En la ERGE se han reportado una disminución del tono vagal (actividad parasimpática) y un aumento de la actividad simpática, con el equilibrio autónomo desplazado hacia el sistema simpático. Los cuestionarios clínicos y la medición de la variabilidad de la frecuencia cardiaca, método no invasor, pueden ser útiles en los pacientes con ERGE para detectar la disfunción autonómica. La restauración de la actividad del sistema parasimpático (principalmente neuromodulación), con la subsecuente mejoría de la actividad parasimpática, disminuirá la intensidad de los síntomas autonómicos y de la ERGE, mejorando la calidad de vida

Flow shop rescheduling under different types of disruption

This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Production Research on 2013, available online:http://www.tandfonline.com/10.1080/00207543.2012.666856Almost all manufacturing facilities need to use production planning and scheduling systems to increase productivity and to reduce production costs. Real-life production operations are subject to a large number of unexpected disruptions that may invalidate the original schedules. In these cases, rescheduling is essential to minimise the impact on the performance of the system. In this work we consider flow shop layouts that have seldom been studied in the rescheduling literature. We generate and employ three types of disruption that interrupt the original schedules simultaneously. 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