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PubMed2000

Comparative performance assessment in managed care: data envelopment analysis for health care managers.

In health care markets increasingly dominated by managed care, health care managers need sophisticated yet understandable comparative performance assessment methods. Ideally, these methods should provide targets for the managers to improve program or organization performance. This article reviews three comparative performance methodologies with a comprehensive explanation of data envelopment analysis (DEA). DEA is a form of linear programming that allows for the inclusion of multiple input and output/outcome performance variables from a virtually unlimited number of organizations, facilitating meaningful health service provider comparative assessments.

Administrative Personnel↗
PubMed2003

Revisiting the decision rule of cost-effectiveness analysis under certainty and uncertainty.

The classical decision rule of cost-effectiveness analysis uses a threshold cost-effectiveness ratio as a cut-off point for resources allocation. One assumption of this decision rule is complete divisibility of health care programs. In this article, we argue that health care programs cannot be completely divisible since individuals are not divisible. Consequently, instead of a linear programming approach, an integer programming approach to budget allocation is suggested. The integer programming framework can be extended to include uncertainty in the analysis. An objective function (expected aggregate effects) is maximised subject to the constraint that the probability of exceeding the budget is limited to an arbitrary level (e.g., 0.05). In case the budget is exceeded, the objective function is penalised in order to account for the opportunity costs of the additional resource requirements.

Budgets↗
PubMed2000

Constant holdup times in gas chromatography by programming of column temperature and inlet pressure

The requirements for attaining constant holdup times in capillary gas chromatography (GC), while linearly programming both column temperature and inlet pressure, are illustrated. A scheme, which is based on a series of responses from isothermal and isobaric conditions, is proposed. The responses from two commonly used GC instruments, one with a mass-selective detector operating at near-vacuum pressure and another with a flame-ionization detector at ambient pressure, are analyzed. A significant deviation from Poiseuille flow is noted due to the use of helium as a carrier gas. Nonetheless, the experimental holdup times are approximately constant over a range of temperatures and pressures. Theoretical analysis reveals the spatial and temporal dependence of flow rates inside the column during the programmed runs.

Journal Article↗
PubMed2004

Stress and compliance with a home exercise program among caregivers of children with disabilities.

PURPOSE: To determine the relationship between caregiver stress and compliance with home programs in caregivers of children with disabilities. METHODS: Sixty-six caregivers of children with disabilities responded to a mailed survey to determine their level of compliance with a prescribed home physical therapy program and the level of caregiver stress. Compliance was defined as the degree to which caregivers followed the prescribed frequency of the home program. RESULTS: Sixty-six percent of the caregivers reported some level of noncompliance with their home program. Linear regression analysis revealed a significant relationship between the caregivers' level of noncompliance with the home program and the level of stress that they reported. Correlation coefficients showed a significant relationship between family problems and noncompliance with home programs. As caregiver and family problems increased, noncompliance with home programs increased. CONCLUSIONS: Caregivers of children with disabilities experience stress that should be addressed by therapists to maximize compliance with home programs.

Journal Article↗
PubMed2003

Epitope prediction algorithms for peptide-based vaccine design.

Peptide-based vaccines, in which small peptides derived from target proteins (eptiopes) are used to provoke an immune reaction, have attracted considerable attention recently as a potential means both of treating infectious diseases and promoting the destruction of cancerous cells by a patient's own immune system. With the availability of large sequence databases and computers fast enough for rapid processing of large numbers of peptides, computer aided design of peptide-based vaccines has emerged as a promising approach to screening among billions of possible immune-active peptides to find those likely to provoke an immune response to a particular cell type. In this paper, we describe the development of three novel classes of methods for the prediction problem. We present a quadratic programming approach that can be trained on quantitative as well as qualitative data. The second method uses linear programming to counteract the fact that our training data contains mostly positive examples. The third class of methods uses sequence profiles obtained by clustering known epitopes to score candidate peptides. By integrating these methods, using a simple voting heuristic, we achieve improved accuracy over the state of the art.

Algorithms↗
PubMed1999

Effects of feeding program and crude protein intake during rearing on fertility of broiler breeder females.

Arbor Acres broiler breeder pullets were grown from hatch to 24 wk on one of four feeding programs that achieved similar cumulative intakes of ME and CP at 24 wk, but not 20 wk (photostimulation), in Experiment 1. Graphing the four programs in terms of feed per bird per day by week of age gave the general shapes of linear, convex, concave, and deeply concave with respect to 0 and 24 wk reference points. The linear program, which achieved 1,192 g CP at 20 wk (photostimulation), as compared to < 1,150 g CP for the two concave programs, exhibited the best fertility. Although the pullets reared on the convex program consumed 1,255 g CP, fertility was poor, probably due to the reduced rate of increase in feed allocation late in rearing that delayed oviduct development. In Experiment 2, pullets were fed to the same cumulative ME intake at 20 wk using either a concave or convex feeding program with respect to 0 and 20 wk reference points with two levels of dietary protein. The higher level of CP intake (1,363 vs 1,212 g) produced higher fertility. A significant feeding program by dietary protein interaction was found. Level of CP intake at photostimulation had no effect on fertility with the concave feeding program but the convex program decreased fertility at the lower CP intake as in Experiment 1.

Animal Husbandry↗
PubMed1978

Distribution of spinal disc pressures in the seated posture subjected to impact.

A musculoskeletal model for the human spine developed by the authors is used for this study. The model takes into account the equilibrium of the vertebral bodies, the intervertebral discs and segments of the upper extremities under the influence of all major muscle and joint forces. Linear programming techniques are used to obtain the muscle load sharing and the disc pressures, based on a preselected linear criterion. The criterion is formulated as a combination of all muscles forces (F), joint forces and ligament action (R,M) with suitable weighting factors, and a minimization is sought of U = F + k1R + k2M. The model is used to study the effect of sudden forward or backward acceleration forces, such as during the impact situation, on the distribution of disc pressures in the spinal column in the unsupported seated posture.

Biomechanical Phenomena↗
PubMed1998

Multimedia system based on programmed instruction in medical genetics: construction and evaluation.

A multimedia system used as an auxiliary didactic tool for teaching medical genetics, HGEN, is based on non-linear programmed instruction and multimedia. HGEN was implemented in layers for PC compatible using MULTIMEDIA TOOLBOOK and DELPHI. It includes basic medical genetics concepts (inheritance patterns and cytogenetics) and it is based on multiple choice questions with images, diagrams and animations. The student-program interaction occurs by choosing an alternative in a question and receiving a specific answer as feedback and additional information. Links send the students to a glossary, to short descriptions of diseases used as examples, or to references for further studies. In order to evaluate the performance of the HGEN the authors used two questionnaires: (a) about the students' background in using computers; and (b) the system efficiency as a didactic tool, the software quality and user satisfaction. HGEN was used by 63 students from three medical schools and it was considered efficient as a learning tool (100%). Furthermore the implementation of a navigation map for frequencies analysis of followed path enable the study to detect structure and content inadequacies that could be correct for version 1.1 and proved to be an efficient tool to optimize a didactic software.

Computer-Assisted Instruction↗
PubMed1998

Optimal internship/residency-interview assignments for health care administration student placement.

Interview assignment is an issue of importance to all health care administration programs containing internships and residencies. More generally, many master's and doctoral level educational programs in social work, clinical psychology, and other health fields are faced with the interview assignment problem. We present a linear programming approach, which has been employed at the Baruch College/Mt. Sinai School of Medicine Graduate Program in Health Care Administration, for determining optimal internship/residency-interview assignments. Specifically, a capacitated transportation model, with the objective of maximizing the overall utility of the interview assignments, was implemented. This research is intended to demonstrate to academic program directors dealing with such problems the value of this objective method and to assist educators in their efforts to optimize the student internship/residency placement process at their various institutions.

Career Choice↗
PubMed2001

Global predictive real-time control of Quebec Urban Community's westerly sewer network.

Quebec Urban Community (QUC) has selected Global Predictive Real-Time Control (GP-RTC) as the most efficient approach to achieve environmental objectives defined by the Ministry of Environment. QUC wants to reduce combined sewer overflows (CSOs) frequency to the St Lawrence river to two events per summer period in order to reclaim the use of Jacques-Cartier Beach for recreational activities and sports of primary contact. QUC's control scheme is based on the Certainty Equivalent Control Open Loop Feedback (CEOLF) strategy which permits one to introduce, at each control period, updated measurements and meteorological predictions. A non-linear programming package is used to find the flow set points that minimise a multi-objective (cost) function, subjected to linear equality and inequality constraints representing the physical and operational constraints on the sewer network. Implementation of GP-RTC on QUC's westerly network was performed in the summer of 1999 and was operational by mid-August. Reductions in overflow volumes with GP-RTC compared to static control are attributed to the optimal use of two existing tunnels as retention facilities as well as the maximal use of the wastewater treatment plant (WWTP) capacity.

Computer Systems↗
PubMed1991

Programmed instruction booklet for cardiac rehabilitation teaching.

Programmed instruction is an underused approach for educating hospitalized patients. This educational technique is based on the work of Skinner, who developed the linear programmed instruction technique. To test the effectiveness of this technique as a patient education tool, a programmed instruction booklet was developed for patients who were hospitalized after myocardial infarction. The booklet included basic information on cardiac anatomy and pathology, risk factors, diet, exercise, and medications. A quasi-experimental study design was implemented in which 59 hospitalized patients who had had a myocardial infarction underwent pretesting and posttesting. Patients were alternately assigned to a control group or an experimental group. The control group (n = 30) participated in the hospital's existing cardiac rehabilitation program, and the experimental group (n = 29) used the programmed instruction booklet. A one-way analysis of variance revealed a statistically significant improvement (p less than 0.05) in the posttest scores of the experimental group. The results of this study support the use of the programmed instruction method as one means of teaching cardiac rehabilitation information to hospitalized patients after myocardial infarction.

Adult↗
PubMedDate not supplied

Cyclic scheduling via integer programs with circular ones.

A fundamental problem of cyclic staffing is to size and schedule a minimum-cost workforce so that sufficient workers are on duty during each time period. This may be modeled as an integer linear program with a cyclically structured 0-1 constraint matrix. We identify a large class of such problems for which special structure permits the ILP to be solved parametrically as a bounded series of network flow problems. Moreover, an alternative solution technique is shown in which the continuous-valued LP is solved and the result rounded in a special way to yield an optimum solution to the ILP.

Operations Research↗
PubMed2006

A fast procedure for optimizing dynamic force distribution in multifingered grasping.

This correspondence deals with the dynamic force distribution (DFD) problem, i.e., computing the contact forces to equilibrate a dynamic external wrench on the grasped object. The sum of the normal force components is minimized for enhancing safety and saving energy. By this optimality criterion, the DFD problem can be transformed into a linear programming (LP) problem. Its objective function is the inner product of the dynamic external wrench and a vector, and the constraints on the vector, given by a set of linear inequalities, define a polytope. The solution to the LP problem can always be attained at the vertex of the polytope called the solution vertex. We notice that the polytope is determined by the grasp configuration. Along with the direction change of the dynamic external wrench, only the solution vertex moves to an adjacent vertex sequentially, whereas the polytope with all its vertices remains unchanged. Therefore, the polytope and the adjacencies of each vertex can be computed in the offline phase. Then, in the online phase, simply search the adjacencies of the old solution vertex for the new one. Without lost of optimality, such a DFD algorithm runs a thousandfold faster than solving the LP problem by the simplex method in real time.

Fingers↗
PubMed2000

Use of computerized mate selection programs to control inbreeding of Holstein and Jersey cattle in the next generation.

The expected role of computerized mate selection programs with regard to inbreeding and lifetime profitability of Holstein and Jersey cattle was examined using data from 25 large registered herds of each breed. Sire selection and mate allocation were carried out using linear programming with the following objectives: 1) minimum inbreeding, 2) maximum net merit subject to a fixed inbreeding threshold, and 3) maximum expected lifetime profit after adjustment for inbreeding depression. Inbreeding of actual matings was similar to inbreeding from random matings, indicating that current inbreeding avoidance programs in these herds are ineffective. Inbreeding was reduced by 1.6 and 1.9% in Holsteins and Jerseys, respectively, when a mate allocation program was applied with service sires and usage levels fixed at the actual values. Benefits of mate selection programs increased when both sire selection and mate pair allocation were considered. Maximization of mean net merit with inbreeding restricted to a fixed level (5% in Holsteins and 8% in Jerseys) led to decreases in inbreeding of 0.9 and 1.4% and increases in lifetime profit of $16.66 and $26.86 in Holsteins and Jerseys, respectively, relative to programs that ignored inbreeding. Maximization of mean expected lifetime profit after adjustment for inbreeding depression decreased inbreeding by 1.8 and 2.8% and increased lifetime profit by $37.37 and $59.77 in Holsteins and Jerseys, respectively. Inbreeding coefficients estimated with pedigree traced to 1985 were inadequate predictors of inbreeding coefficients estimated with pedigrees traced to 1960. Mate selection programs cannot function optimally unless extensive historical pedigree data are available, particularly for service sires. Computerized mate selection programs can reduce inbreeding in the next generation, which will lead to an increase in farm profitability. However, if genetic diversity is to be maintained in the long term, procedures for selecting parents of AI sires must also be considered.

Algorithms↗
PubMed1982

An application of mathematical programming concepts to behavioural research design.

More and more frequently, human factors specialists are being asked to design behavioural research and evaluation techniques that will be applied many times to many different systems, and not always by behavioural scientists. One way to meet the repeatability requirement is to base evaluation technique design on the concepts of mathematical optimisation (eg, linear programming). This paper presents a general model for the application of mathematical programming concepts to behavioural research design, and an example of the use of this approach to design a simulator certification programme for the Strategic Air Command (SAC).

Journal Article↗
PubMed1987

Devising a cooperation policy for emergency networks.

A mathematical programming model is proposed to select an optimal cooperation policy between autonomous service networks for dispatching purposes. In addition to traditional characteristics such as network topology and station location, this model takes into account 'political' constraints on minimum response-time in certain subzones. Such constraints are translated into performance requirements, which are imposed on the cooperation policy. Testing the model under different assumptions can be useful for analysing various cooperation policies. The paper formulates a mathematical programming model, derives example policies for various circumstances, and tests the sensitivity of the resultant policies to some parameters, such as the penalty for not providing service, and distances between adjacent networks. The paper suggests also a less constrained approach, which entails a linear programming model. A comparison between the two approaches is presented.

Cooperative Behavior↗
PubMed1998

Validation of voting committees.

This article contains a method to bound the test errors of voting committees with members chosen from a pool of trained classifiers. There are so many prospective committees that validating them directly does not achieve useful error bounds. Because there are fewer classifiers than prospective committees, it is better to validate the classifiers individually than use linear programming to infer committee error bounds. We test the method using credit card data. Also, we extend the method to infer bounds for classifiers in general.

Artificial Intelligence↗
PubMed2002

Intact glucosinolate analysis in plant extracts by programmed cone voltage electrospray LC/MS: performance and comparison with LC/MS/MS methods.

We present a comprehensive, sensitive, and highly specific negative ion electrospray LC/MS method for identifying all structural classes of glucosinolates in crude plant extracts. The technique is based on the observation of simultaneous maxima in the abundances of the m/z 96 and 97 ions, generated by programmed cone voltage fragmentation, in the mass chromatogram. The abundance ratios lie in the range 1:2-1:4 ([m/z 96]/[m/z 97]). Examination of the corresponding full-scan mass spectra allows individual glucosinolates of all structural classes to be identified rapidly and with confidence. The use of linearly programmed cone voltage fragmentation enhances characteristic fragment ions without compromising the abundance of the analytically important [M - H]- ion and its associated (and analytically useful) sulfur isotope peaks. Detection limits are in the low nanogram range for full-scan, programmed cone voltage spectra. Comparison of the technique with LC/MS/MS methods (product ion, precursor ion, and constant neutral loss scans) has shown that the sensitivity and selectivity of the programmed cone voltage method is superior. Data obtained on a variety of plant extracts confirmed that the methodology was robust and reliable.

Chromatography, High Pressure Liquid↗