The key issue affecting Cognitive Diagnostic Models (CDMs) is how to specify attributes and the Q-matrix. In this paper, we first attempt to use the Boolean Matrix Factorization (BMF) method to express conjunctive models in CDMs. Because BMF is an NPhard problem [2], we propose a recursive method that updates the attribute matrix (its rank equals to one) in each step. As Boolean algebra is irre...

This research investigates how information and material distortions affect the inventory management performance of a major retailer. Bullwhip effects (BWEs) are individually calculated for dozens of products carried by dozens of retail locations. Relationships between item/store-level BWEs and item/store-level performance measures including gross margins and inventory levels are tested and repo...

For the (S − 1, S) lost sales inventory model with several demand classes that have different lost sale penalty cost, three accurate and efficient heuristic algorithms are presented that, at a given base stock level, aim to find optimal values for the critical levels, i.e., values that minimize inventory holding and penalty cost.

This work deals with the problem of minimizing the waste of space that occurs on a rotational placement of a set of irregular bi-dimensional small items inside a bidimensional large object. This problem is approached with an heuristic based on simulated annealing. Traditional “external penalization” techniques are avoided through the application of the no-fit polygon, that determinates the coll...

This paper studies the inventory system of a retailer who orders his products from two supply sources, a local one that is responsive and reliable, but expensive, and a global one that is low-cost but less reliable. The deliveries from the global source only partially satisfy the quality requirements.Wemodel this situationwith a dual-sourcing inventory model with positive lead times and random ...

Vocational interest inventories are commonly analyzed using a unidimensional approach, that is, each subscale is analyzed separately. However, the theories on which these inventories are based often postulate specific relationships between the interest traits. This article presents a multidimensional approach to the analysis of vocational interest data, which takes these relationships into acco...

This article presents the use of the Simulated Annealing algorithm with a heuristic to solve the waste minimization problem in roll cutting programming, in this case, paper. Client orders, which vary in weight, width, and external and internal diameter, are fully satisfied. Several tests were performed with real data from a paper company in which an average of 30% waste reduction and 100% reduc...

BACKGROUND The Ruminative Response Scale (RRS)-short form is one of the most widely used measures of rumination, comprising ten items and two components: reflection and brooding. The aim of this study was to investigate RRS validity and reliability in a clinical sample of French patients with major depressive disorder (MDD). SUBJECTS AND METHODS Outpatients with a DSM-IV-TR diagnosis of MDD w...

In this article, we describe the factor structure in both self-reports and peer ratings of the items in a cross-cultural Big-Five inventory in Croatia. Using 2 versions of an inventory developed from the International Personality Item Pool (IPIP; Goldberg, 1999), this is one of the first cross-national analyses of these IPIP measures. A large sample of university students (N = 519) used the tra...