Fuzzy Multi-Objective Linear Programming and Simulation Approach to the Development of Valid and Realistic Master Production Schedule

Master production schedule (MPS) plays an important role in an integrated production planning system. It converts the strategic planning defined in a production plan into the tactical operation execution. The MPS is also known as a tool for top management to control over manufacture resources and becomes input of the downstream planning levels such as material requirement planning (MRP) and capacity requirement planning (CRP). Hence, inappropriate decision on the MPS development may lead to infeasible execution, which ultimately causes poor delivery performance. One must ensure that the proposed MPS is valid and realistic for implementation before it is released to real manufacturing system. In practice, where production environment is stochastic in nature, the development of MPS is no longer simple task. The varying processing time, random event such as machine failure is just some of the underlying causes of uncertainty that may be hardly addressed at planning stage so that in the end the valid and realistic MPS is tough to be realized. The MPS creation problem becomes even more sophisticated as decision makers try to consider multi-objectives; minimizing inventory, maximizing customer satisfaction, and maximizing resource utilization. This study attempts to propose a methodology for MPS creation which is able to deal with those obstacles. This approach takes into account uncertainty and makes trade off among conflicting multi-objectives at the same time. It incorporates fuzzy multi-objective linear programming (FMOLP) and discrete event simulation (DES) for MPS development.

Is characterization of a single isolate sufficient for valid publication of a new genus or species? Proposal to modify recommendation 30b of the Bacteriological Code (1990 Revision)

From 1990 to 2000, the number of published named taxa based upon new isolates at species and genus levels in International Journal of Systematic and Evolutionary Microbiology, formerly International Journal of Systematic Bacteriology, have increased by approximately four- and sevenfold, respectively. New taxa based upon characterization of only a single isolate remained at around 40% for both categories. The Bacteriological Code (1990 Revision) has no recommendations on the number of strains required for definition of new taxa. For a few groups, a minimum number of 5-10 strains has been suggested in minimal standards. Since an exponential increase in new taxa can be expected in the future, the authors discuss problems related to naming new species and genera based upon descriptions of a single isolate and suggest that this practice is re-evaluated. It is proposed that the following should be added to Recommendation 30b of the Bacteriological Code: 'Descriptions should be based on as many strains as possible (minimum five), representing different sources with respect to geography and ecology in order to be well characterized both phenotypically and genotypically, to establish the centre (from which the type strain could be chosen) and the extent of the cluster to be named. In addition, comparative studies should be performed, including reference strains that represent neighbouring species and/or genera, in order to give descriptions that are sufficiently detailed to allow differentiation from these neighbours.'

Combining follow-up and change data is valid in meta-analyses of continuous outcomes: a meta-epidemiological study

OBJECTIVE To investigate whether it is valid to combine follow-up and change data when conducting meta-analyses of continuous outcomes. STUDY DESIGN AND SETTING Meta-epidemiological study of randomized controlled trials in patients with osteoarthritis of the knee/hip, which assessed patient-reported pain. We calculated standardized mean differences (SMDs) based on follow-up and change data, and pooled within-trial differences in SMDs. We also derived pooled SMDs indicating the largest treatment effect within a trial (optimistic selection of SMDs) and derived pooled SMDs from the estimate indicating the smallest treatment effect within a trial (pessimistic selection of SMDs). RESULTS A total of 21 meta-analyses with 189 trials with 292 randomized comparisons in 41,256 patients were included. On average, SMDs were 0.04 standard deviation units more beneficial when follow-up values were used (difference in SMDs: -0.04; 95% confidence interval: -0.13, 0.06; P=0.44). In 13 meta-analyses (62%), there was a relevant difference in clinical and/or significance level between optimistic and pessimistic pooled SMDs. CONCLUSION On average, there is no relevant difference between follow-up and change data SMDs, and combining these estimates in meta-analysis is generally valid. Decision on which type of data to use when both follow-up and change data are available should be prespecified in the meta-analysis protocol.

Modulus and Poincaré Inequalities on Non-Self-Similar Sierpiński Carpets

A carpet is a metric space homeomorphic to the Sierpiński carpet. We characterize, within a certain class of examples, non-self-similar carpets supporting curve families of nontrivial modulus and supporting Poincaré inequalities. Our results yield new examples of compact doubling metric measure spaces supporting Poincaré inequalities: these examples have no manifold points, yet embed isometrically as subsets of Euclidean space.

Educational Expansion and Persistent Inequalities of Education: Utilizing the Subjective Expected Utility Theory to Explain the Increasing Participation Rates in Upper Secondary School in the Federal Republic Of Germany

This investigation attempts to answer the question why more and more parents have chosen the Gymnasium for their children's secondary school education in post‐war West Germany. Based on the theory of subjective expected utility, the crucial mechanisms of parental educational decisions have been emphasized. From this perspective it is assumed that increasing educational motivation coupled with changes in the subjective evaluation of the cost–benefit of education were important conditions for an increasing participation in upper secondary schools. These were, however, in turn, the result of educational expansion. The empirical analyses for three time‐periods in the 1960s, 1970s, and 1980s confirm these assumptions to a large degree. Additionally, empirical evidence was found to suggest that in addition to the intentions of parents and the educational career of their children, structural moments of educational expansion and their own inertia played an important role in the pupils' transition from one educational level to the next. Finally, evidence was found that persistent class‐specific educational inequality stems from a constant balance in the relative cost–benefit advantages between social classes as well as from an increasing difference of primary origin effect between social classes in the realization of their educational choice.

The Coin Rotation Task: A Valid Test for Manual Dexterity in Multiple Sclerosis

BACKGROUND: Impaired manual dexterity is frequent and disabling in patients with multiple sclerosis (MS). Therefore, convenient, quick and validated tests for manual dexterity in MS patients are needed. OBJECTIVE: The aim of this study was to validate the Coin Rotation task (CRT) to examine manual dexterity in patients with MS. DESIGN: Cross-sectional study. METHODS: 101 outpatients with MS were assessed with the CRT, the Expanded Disability Status Scale (EDSS), the Scale for the assessment and rating of ataxia (SARA), the Modified Ashworth Scale (MAS), and their muscle strength and sensory deficits of the hands were noted. Concurrent validity and diagnostic accuracy of the CRT were determined by comparison with the Nine Hole Peg Test (9HPT). Construct validity was determined by comparison with a valid dexterity questionnaire. Multiple regression analysis was done to explore correlations of the CRT with the EDSS, SARA, MAS, muscle strength and sensory deficits. RESULTS: The CRT correlated significantly with the 9HPT (r=.73, p<.0001) indicating good concurrent validity. The cut-off values for the CRT relative to the 9HPT were 18.75 seconds for the dominant (sensitivity: 81.5%; specificity 80.0%) and 19.25 seconds for the non-dominant hand (sensitivity: 90.3%; specificity: 81.8%) demonstrating good diagnostic accuracy. Furthermore, the CRT correlated significantly with the dexterity questionnaire (r=-.49, p<.0001) indicating moderate construct validity. Multiple regression analyses revealed that the EDSS was the strongest predictor for impaired dexterity. LIMITATIONS: Mostly relapsing-remitting MS patients with an EDSS up to 7 were examined. CONCLUSIONS: This study validates the CRT as a test that can be used easily and quickly to evaluate manual dexterity in patients with MS.

A new method to facilitate valid and consistent grading cardiac events in childhood cancer survivors using medical records

BACKGROUND Cardiac events (CEs) are among the most serious late effects following childhood cancer treatment. To establish accurate risk estimates for the occurrence of CEs it is essential that they are graded in a valid and consistent manner, especially for international studies. We therefore developed a data-extraction form and a set of flowcharts to grade CEs and tested the validity and consistency of this approach in a series of patients. METHODS The Common Terminology Criteria for Adverse Events version 3.0 and 4.0 were used to define the CEs. Forty patients were randomly selected from a cohort of 72 subjects with known CEs that had been graded by a physician for an earlier study. To establish whether the new method was valid for appropriate grading, a non-physician graded the CEs by using the new method. To evaluate consistency of the grading, the same charts were graded again by two other non-physicians, one with receiving brief introduction and one with receiving extensive training on the new method. We calculated weighted Kappa statistics to quantify inter-observer agreement. RESULTS The inter-observer agreement was 0.92 (95% CI 0.80-1.00) for validity, and 0.88 (0.79-0.98) and 0.99 (0.96-1.00) for consistency with the outcome assessors who had the brief introduction and the extensive training, respectively. CONCLUSIONS The newly developed standardized method to grade CEs using data from medical records has shown excellent validity and consistency. The study showed that the method can be correctly applied by researchers without a medical background, provided that they receive adequate training.

The VEINES-QOL/Sym questionnaire is a reliable and valid disease-specific quality of life measure for deep vein thrombosis in elderly patients.

PURPOSE To prospectively evaluate the psychometric properties of the Venous Insufficiency Epidemiological and Economic Study (VEINES-QOL/Sym) questionnaire, an instrument to measure disease-specific quality of life and symptoms in elderly patients with deep vein thrombosis (DVT), and to validate a German version of the questionnaire. METHODS In a prospective multicenter cohort study of patients aged ≥ 65 years with acute venous thromboembolism, we used standard psychometric tests and criteria to evaluate the reliability, validity, and responsiveness of the VEINES-QOL/Sym in patients with acute symptomatic DVT. We also performed an exploratory factor analysis. RESULTS Overall, 352 French- and German-speaking patients were enrolled (response rate of 87 %). Both language versions of the VEINES-QOL/Sym showed good acceptability (missing data, floor and ceiling effects), reliability (internal consistency, item-total and inter-item correlations), validity (convergent, discriminant, known-groups differences), and responsiveness to clinical change over time in elderly patients with DVT. The exploratory factor analysis of the VEINES-QOL/Sym suggested three underlying dimensions: limitations in daily activities, DVT-related symptoms, and psychological impact. CONCLUSIONS The VEINES-QOL/Sym questionnaire is a practical, reliable, valid, and responsive instrument to measure quality of life and symptoms in elderly patients with DVT and can be used with confidence in prospective studies to measure outcomes in such patients.

Delayed HIV diagnosis and initiation of antiretroviral therapy: inequalities by educational level, COHERE in EuroCoord.

OBJECTIVES In Europe and elsewhere, health inequalities among HIV-positive individuals are of concern. We investigated late HIV diagnosis and late initiation of combination antiretroviral therapy (cART) by educational level, a proxy of socioeconomic position. DESIGN AND METHODS We used data from nine HIV cohorts within COHERE in Austria, France, Greece, Italy, Spain and Switzerland, collecting data on level of education in categories of the UNESCO/International Standard Classification of Education standard classification: non-completed basic, basic, secondary and tertiary education. We included individuals diagnosed with HIV between 1996 and 2011, aged at least 16 years, with known educational level and at least one CD4 cell count within 6 months of HIV diagnosis. We examined trends by education level in presentation with advanced HIV disease (AHD) (CD4 <200 cells/μl or AIDS within 6 months) using logistic regression, and distribution of CD4 cell count at cART initiation overall and among presenters without AHD using median regression. RESULTS Among 15 414 individuals, 52, 45,37, and 31% with uncompleted basic, basic, secondary and tertiary education, respectively, presented with AHD (P trend <0.001). Compared to patients with tertiary education, adjusted odds ratios of AHD were 1.72 (95% confidence interval 1.48-2.00) for uncompleted basic, 1.39 (1.24-1.56) for basic and 1.20 (1.08-1.34) for secondary education (P < 0.001). In unadjusted and adjusted analyses, median CD4 cell count at cART initiation was lower with poorer educational level. CONCLUSIONS Socioeconomic inequalities in delayed HIV diagnosis and initiation of cART are present in European countries with universal healthcare systems and individuals with lower educational level do not equally benefit from timely cART initiation.