This paper considers the design and analysis of algorithms for vehicle routing and scheduling problems with time window constraints. Given the intrinsic difficulty of this problem class, approximation methods seem to offer the most promise for practical size problems. After describing a variety of heuristics, we conduct an extensive computational study of their performance. The problem set includes routing and scheduling environments that differ in terms of the type of data used to generate the problems, the percentage of customers with time windows, their tightness and positioning, and the scheduling horizon. We found that several heuristics performed well in different problem environments; in particular an insertion-type heuristic consistently gave very good results.

https://www.jstor.org/stable/pdfplus/170697.pdf

Algorithms for the vehicle routing and scheduling problems with time window constraints

Estimation and inference in two-stage, semi-parametric models of production processes

Data envelopment analysis (DEA) - Thirty years on

Efficiency decomposition in two-stage data envelopment analysis: an application to non-life insurance companies in taiwan

https://www.grips.ac.jp/r-center/wp-content/uploads/07-08.pdf

Network DEA: A slacks-based measure approach

Online learning environments have become a standard support for most higher education courses, whether they are face to face, hybrid, or online. During their years of study, today’s students will need to navigate these online learning environments: from finding the syllabus to interacting with the faculty virtually. However, not all learners have equal facility when dealing with online environments. In this article we report results of two exploratory studies investigating cognitive characteristics involved in learning and personal pre-requisites that are important for a positive learner experience in an online learning environment. In particular, we examined the perceived easiness of use and perceived helpfulness of the OLE, as related to the user’s digital fluency and spatial ability. Logistic regression of scores in digital fluency (DF) tests on dichotomized survey responses demonstrated that senior undergraduate students with higher DF scores find online learning environments easy to use, and helpful, more often than their peers having lower DF scores. Comparison of mental rotation scores with the digital fluency scores, by means of linear regression analysis, demonstrated statistically significant association between spatial ability and digital fluency. As previous studies demonstrated that spatial ability can be trained, these results will facilitate digital readiness for the expansion of educational ecosystem and will help people to make better use of eLearning materials.

Role of Digital Fluency and Spatial Ability in Student Experience of Online Learning Environments

On the wisdom of mandatory drug testing

Data envelopment analysis (DEA) assumes that inputs and outputs are measured on scales in which larger numerical values correspond to greater consumption of inputs and greater production of outputs. We present a class of DEA problems in which one or more of the inputs or outputs are naturally measured on scales in which higher numerical values represent lower input consumption or lower output production. We refer to such quantities as reverse inputs and reverse outputs. We propose to incorporate reverse inputs and outputs into a DEA model by returning to the basic principles that lead to the DEA model formulation. We compare our method to reverse scoring, the most commonly used approach, and demonstrate the relative advantages of our proposed technique. We use this concept to analyze all 30 Major League Baseball (MLB) organizations during the 1999 regular season to determine their on-field and front office relative efficiencies. Our on-field DEA model employs one output and two symmetrically defined inputs, one to measure offense and one to measure defense. The defensive measure is such that larger values correspond to worse defensive performance, rather than better, and hence is a reverse input. The front office model uses one input. Its outputs, one of which is a reverse output, are the inputs to the on-field model. We discuss the organizational implications of our results.

Data Envelopment Analysis with Reverse Inputs

In the current economic climate, business schools face crucial decisions. As resources become scarcer, schools must either streamline operations or limit them. An efficiency analysis of U.S. business schools is presented that computes, for each business school, an overall efficiency score and provides separate factor efficiency scores, indicating the extent to which the school can reduce each resource and increase each output. Using data envelopment analysis and AACSB data, the model rates the managerial performance of 438 U.S. business schools. For 21.5% of the schools, the analysis finds no evidence that they can improve their performance. For each remaining school, the analysis identifies the extent to which it can improve its overall efficiency and its efficiency within specific areas. The results are useful to business schools in developing long-term strategic plans, making resource allocation decisions, preparing for AACSB accreditation review, and improving overall performance.

/pdf/an-efficiency-analysis-of-u-s-business-schools-1ms2ub7vlq.pdf

An Efficiency Analysis of U.S. Business Schools.

A mathematical model for predicting the future course of the AIDS epidemic permits the evaluation of a number of possible scenarios for male homosexuals in the US and finds that, while the epidemic can be mitigated, a combination of strategies will probably be needed. Steps to lower the transmissibility of the virus and to encourage more widespread testing and abstinence from risky sex practices are the most promising; merely reducing the rate of acquisition of new sexual partners without decreasing total sexual activity will have only a minor impact. A drug that increases the time from initial infection to the development of AIDS and the time from development of AIDS to death improves the short-term situation at the expense of the long-term if no cure is found. The presence of such a drug in conjunction with the other interventions is, in certain ways, worse than its absence. The model is used to estimate that between 24 and 52 new large urban hospitals will be needed to accommodate male homosexual AIDS patients, perhaps as soon as 1997.

Thomas R. Sexton

Papers

Role of Digital Fluency and Spatial Ability in Student Experience of Online Learning Environments

On the wisdom of mandatory drug testing

Data Envelopment Analysis with Reverse Inputs

An Efficiency Analysis of U.S. Business Schools.

Long-Term Projections of the AIDS Epidemic