Determination of anaerobic threshold

This report describes the estimation of the parameters for a model of ventilation (y) by human subjects as a two-segment linear function of oxygen uptake (x). Experimental data were supplied by R.L. Hughson of the Department of Kinesiology. The analysis of one of nine available sets of data is described in detail.     

Multilocation plant sizing and timing problem: a study of spatial—temporal decomposition procedure

An attempt has been made to develop a spatial-temporal decomposition procedure to solve the multilocation plant sizing and timing problem (MLPSTP). MLPSTP involves the determination of site, location, timing and utilization of the plants to meet the demands of geographically distributed customers. These decisions are assumed to interact through a common objective of minimizing the net present value (NPV) of capital costs and streams of operating and transportation costs. A solution procedure for MLPSTP is proposed using aggregation and disaggregation methodology. In the aggregation phase, MLPSTP is considered to be a single-period problem. This problem is decomposed over different geographical areas to obtain a set of feasible sites and projects. These projects are then sequenced over a finite planning horizon in the disaggregation phase. A multiple criteria based evaluation of spatial decomposition, temporal decomposition, and spatial-temporal decomposition is provided.     

A unified approach to restricted games

There have been two main lines in the literature on restricted games: the first line was started by Myerson (1977) that studied graph-restricted games an the second one was initiated by Faigle (1989). The present paper provides a unified way to look on the literature and establishes connections between the two different lines on restricted games. The strength and advantages of this unified approach becomes clear in the study of the inheritance of the convexity from the game to the restricted game where an interesting result by Nouweland and Borm (1991) on the convexity of graph-restricted games is turned into a direct consequence of the corresponding result by Faigle (1989), by means of this relation. This revised version was published online in June 2006 with corrections to the Cover Date.     

OPTIMIRUS. Simulating Population Change in the Russian Far East

This article examines the population trends in the cities of the Russian Far East between the two census years 1989 and 2002. Three geographical models – Rank-Size Rule, Temperature per Capita and a simple gravity model – are used to describe the direction of these population trends. An economic efficiency function is constructed from the three models to simulate an ideal population distribution for the Russian Far East. The heart of the simulation is a conjugate gradient optimisation of the economic efficiency function. The results serve as an important backdrop to discussions of current population trends and serve as an important backdrop to discussions of current population trends and as basis for recommendations concerning future changes in the spatial distribution of population in the region.Mueller, K., et Bradshaw M. J., 2006. OPTIMIRUS. Une simulation des variations de population dans l’Extrême-Orient russe. Revue européenne de démographie, 22:105–126.     

On the Tukey depth of an atomic measure

This paper gives a relation between the convex Tukey trimmed region (see [J.C. Massé, R. Theodorescu, Halfplane trimming for bivariate distributions, J. Multivariate Anal. 48(2) (1994) 188–202]) of an atomic measure and the support of the measure. It is shown that an atomic measure is concentrated on the extreme points of its Tukey trimmed region. A property concerning the extreme points which have 0 mass is given. As a corollary, we give a new method of proof of the Koshevoy characterization result.     

Development and implementation of an operating room scheduling tool: an action research study

In this study, we report the results of an action research project whose aim was to develop and implement an operating room scheduler at the Meyer University Children’s Hospital. The study offers insights into the features that make an MSS optimisation model and scheduler effective and easy to implement, and shed light on those actions facilitating their introduction and use. Specifically, it suggests that creating an effective operating room scheduler requires clustering patients in homogeneous surgery groups and developing a flexible tool that allows: scheduling surgery groups instead of actual patients, easily adding/removing constraints, changing the objective function(s) and adjusting the planning horizon. In addition, it posits that gaining the commitment of top management by showing credible preliminary results, inferring stakeholder preferences by letting them comment on tentative schedules, introducing changes gradually and involving staff at lower levels of the hospital hierarchy can significantly facilitate the scheduler development and implementation.     

Decision process of allocating projects to project managers

Allocating projects to project managers (PM) is a crucial decision in project management. Choosing the PM must be undertaken in a structured way, and thereby take into account the needs of the project and the PM’s competences and availability. The proposed model optimises the total time that PMs have available and takes into account the constraint of the switchover time loss within the mathematical programming. It model is part of a three-stage approach where: (1) projects are sorted using a multicriteria approach; (2) PMs are sorted using a multicriteria approach; and (3) the final allocation to intra-classes of projects is made using the optimisation model. This proposal contributes to aiding decision-makers involved in allocating projects: by respecting the limit of the time that PMs have available, or by extrapolating PMs’ available hours in which case overtime will have to be used. The model is applied in a Brazilian Energy Company.     

三维空间上凸函数的判定

本文从凸集入手,着力讨论空间上凸(凹)曲面的几何特征,并给出判定空间上凸函数的几个充要条件。     

Sharp upper mean-variance bounds for trimmed means from restricted families

We apply the method of projection to derive sharp upper mean-variance bounds on trimmed means of order statistics of i.i.d. samples coming from restricted families of probability measures. Two families are considered: distributions with decreasing density and decreasing failure rate. We also present some numerical results.