A new dynamic programming formulation of (n x m) flowshop sequencing problems with due dates

A dynamic programming formulation is presented for determining an optimal solution to a problem where n jobs are to be sequenced in a multi-stage production environment. An application of a developed formulation to a plastic pipe manufacturing factory is also presented. Conditions are such that the job sequence is the same in all stages, each job requires setups at each stage and setup times are sequence dependent. An optimal solution is such that the minimum total tardiness is achieved. A listing of the developed computer program is also provided

Dynamic optimization of multipass milling operations via geometric programming

This paper outlines the development of an optimization strategy to determine the optimum cutting parameters for multipass milling operations like plain milling and face milling. The developed strategy is based on the "maximum production rate" criterion and incorporates eight technological constraints. The optimum number of passes is determined via dynamic programming, and the optimal values of the cutting conditions are found based on the objective function developed for the typified criterion by using a non-linear programming technique called "geometric programming". This paper also underlies the importance of using optimization strategies rather than handbook recommendations as well as pointing out the superiority of the multipass over the single-pass optimization approach. (C) 1998 Elsevier Science Ltd. All rights reserved

OPPS-ROT: An optimised process planning system for rotational parts

This paper presents an optimised process planning system for rotational parts. The model of a part is drawn by using a CAD module prepared for this purpose. After the feature recognition module, machining operations are determined and the cutting tools are selected by using the knowledge base and machining topology. An optimum sequence of operations is found by minimising the number of tool changes and tool travelling distance to decrease the cost per operation. The optimum cutting conditions are determined and stored in a CAD/CAM data base, accordingly. The part programs are then automatically generated in standard ISO codes on the basis of specific CNC lathe controllers. The generated part programs as well as tool paths can also be verified by graphical simulation prior to actual machining. The system is intelligent and requires little manual intervention. It is implemented with C + + on a personal computer

Preliminary Evidence for Anhedonia as a Marker of Sexual Trauma in Female Adolescents

Ayse Irem Sonmez,1,2 Charles P Lewis,1 Arjun P Athreya,3 Julia Shekunov,2 Paul E Croarkin2 1Department of Psychiatry and Behavioral Sciences, University of Minnesota Medical School, Minneapolis, MN, USA; 2Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA; 3Department of Molecular Pharmacology &Experimental Therapeutics, Mayo Clinic, Rochester, MN, USACorrespondence: Ayse Irem SonmezDepartment of Psychiatry and Behavioral Sciences, University of Minnesota Medical School, 2312 S 6th St, Minneapolis, MN, 55454, USATel +1 612-273-8383Email [email protected]: Major depressive disorder (MDD) is a common condition with heterogeneous presentations that often include predominant anhedonia. Previous studies have revealed that childhood trauma is a potent risk factor for the development of MDD; however, the clinical implications of this finding are not fully understood.Methods: Participants were adolescents (age 13– 21 years) with a diagnosis of moderate-to-severe major depressive disorder and healthy controls. We used generalized linear models to assess the relationship between anhedonia severity and trauma severity in a cross-sectional dataset.Results: This cross-sectional analysis of an adolescent sample that underwent clinical evaluations and a trauma assessment, suggested that anhedonia was associated with historical trauma severity. The association between anhedonia and sexual abuse was greater in female participants compared to male participants.Discussion: Our results were partially in line with the reported literature in adult samples. Future studies aiming to characterize the trauma–anhedonia relationship in adolescents should utilize scales designed specifically to measure these constructs in young populations, and scales that assess specific subtypes of anhedonia.Keywords: adolescent, anhedonia, emotional abus