Large-scale unit commitment under uncertainty: an updated literature survey

The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

Ethnicity and disease severity in ankylosing spondylitis a cross-sectional analysis of three ethnic groups.

The purpose of this study is to compare disease severity in ankylosing spondylitis (AS) in three ethnic groups. We assessed 925 AS patients (57 Blacks, 805 Whites, 63 Latinos) enrolled in the longitudinal Prospective Study of Outcomes in AS (PSOAS) for functional impairment, disease activity, and radiographic severity. Comparisons of clinical characteristics and HLA-B27 frequency for each group were performed, in two multivariable regression models, we compared the baseline Bath Ankylosing Spondylitis Radiographic Index (BASRI) and modified Stokes Ankylosing Spondylitis Spine Score (mSASSS) by ethnicity, adjusting for covariates. Blacks had greater functional impairment (Bath Ankylosing Spondylitis Functional Index) (median 62.5 vs. 27.8 in Whites and 38.1 in Latinos; p < 0.0001); higher disease activity (Bath Ankylosing Spondylitis Disease Activity Index), (median 5.9 vs. 3.5 in Whites and 4.5 in Latinos; p < 0.0001), erythrocyte sedimentation rate (median 27.0 in Blacks vs. 10.0 in Whites and 17.0; p < 0.0001), and C-reactive protein levels (median 1.2 vs. 0.4 mg/dL in Whites and 0.9 in Latinos; p < 0.0001). Baseline BASRI and mSASSS were higher in Blacks (mean 9.5 and median 38.2, respectively) compared to Whites (7.3 and 6.4) and Latinos (7.3 and 8.1), (p = 0.004, 0.007), respectively, more significant as disease duration increased. HLA-B27 occurred in 62.5% of Blacks, 85.3% of Whites, and 86.7% of Latinos (p < 0.0001). On multivariable analysis, higher BASRI and mSASSS were associated with Black ethnicity, after adjusting for disease duration and gender as well as TNF inhibitor (TNFi) usage, smoking status, or education level. Blacks with AS have more severe disease compared to either Whites or Latinos

Ethnicity and disease severity in ankylosing spondylitis a cross-sectional analysis of three ethnic groups

The purpose of this study is to compare disease severity in ankylosing spondylitis (AS) in three ethnic groups. We assessed 925 AS patients (57 Blacks, 805 Whites, 63 Latinos) enrolled in the longitudinal Prospective Study of Outcomes in AS (PSOAS) for functional impairment, disease activity, and radiographic severity. Comparisons of clinical characteristics and HLA-B27 frequency for each group were performed, in two multivariable regression models, we compared the baseline Bath Ankylosing Spondylitis Radiographic Index (BASRI) and modified Stokes Ankylosing Spondylitis Spine Score (mSASSS) by ethnicity, adjusting for covariates. Blacks had greater functional impairment (Bath Ankylosing Spondylitis Functional Index) (median 62.5 vs. 27.8 in Whites and 38.1 in Latinos; p < 0.0001); higher disease activity (Bath Ankylosing Spondylitis Disease Activity Index), (median 5.9 vs. 3.5 in Whites and 4.5 in Latinos; p < 0.0001), erythrocyte sedimentation rate (median 27.0 in Blacks vs. 10.0 in Whites and 17.0; p < 0.0001), and C-reactive protein levels (median 1.2 vs. 0.4 mg/dL in Whites and 0.9 in Latinos; p < 0.0001). Baseline BASRI and mSASSS were higher in Blacks (mean 9.5 and median 38.2, respectively) compared to Whites (7.3 and 6.4) and Latinos (7.3 and 8.1), (p = 0.004, 0.007), respectively, more significant as disease duration increased. HLA-B27 occurred in 62.5% of Blacks, 85.3% of Whites, and 86.7% of Latinos (p < 0.0001). On multivariable analysis, higher BASRI and mSASSS were associated with Black ethnicity, after adjusting for disease duration and gender as well as TNF inhibitor (TNFi) usage, smoking status, or education level. Blacks with AS have more severe disease compared to either Whites or Latinos

Repeated Spinal Mobility Measures and Their Association With Radiographic Damage in Ankylosing Spondylitis

Objective: We sought to explore the relationship between changes in repeated mobility measures and spinal structural progression in patients with ankylosing spondylitis (AS) over time. Methods: We studied patients with AS from the PSOAS (Prospective Study of Outcomes in AS) cohort and performed longitudinal multivariable regression modeling to assess the relationship of structural damage measured by their regional (cervical or lumbar) modified Stoke AS Spinal Score(mSASSS) and selected cervical (eg, cervical rotation, lateral bending, and occiput-to-wall distance) and lumbar spinal mobility measures (eg, Schöber’s test and lumbar lateral bending) that were collected at least every 2 years from 2003 to 2019. Results: The median length of follow-up for our 518 patients with cervical mSASSS measurements and 573 with lumbar mSASSS measurements was 4.08 (interquartile range [IQR] 2.25-6.67) and 4.17 (IQR 2.25-6.67) years, respectively. Among the mobility measures, based on multivariable regression models adjusting for clinical/demographic variables and C-reactive protein, we did not observe meaningful associations between changes in spinal mobility with their respective regional mSASSS. Baseline mSASSS, male sex, increased C-reactive protein (CRP), and longer disease duration were associated with increased longitudinal mSASSS in all analyses. Conclusion: Our study shows that 2-year changes in individual spinal mobility measures are not reliably associated with increased, longitudinal, AS-related spinal structural progression. We also confirmed the relationship of baseline mSASSS, sex, CRP, and disease duration with AS-related structural spinal progression over time.</p

Longitudinal associations between depressive symptoms and clinical factors in ankylosing spondylitis patients: analysis from an observational cohort

Objectives: Although cross-sectional studies have shown that ankylosing spondylitis-specific factors correlate with depressive symptom severity, the association of these factors over time is unresolved. We examined the demographic and clinical factors associated with longitudinal depressive symptom severity in AS patients. Methods: We analyzed sociodemographic, clinical, behavioral and medication data from 991 patients from the Prospective Study of Outcomes in Ankylosing spondylitis cohort, and measured depression severity with the Center for Epidemiological Studies Depression (CES-D) Scale administered at approximately 6-month visit intervals. Multivariable longitudinal negative binomial regression models were conducted using generalized estimating equation modeling to assess the demographic, clinical, and medication-related factors associated with depression severity by CES-D scores over time. Results: The median baseline CES-D score (possible range 0–60) was 10.0 (interquartile range = 5, 17). In longitudinal multivariable analyses, higher CES-D scores were associated with longitudinal smoking, greater functional impairment, greater disease activity, self-reported depression, and poor global health scores. Marital status (e.g., being married) was associated with lower CES-D. Adjusted mean CES-D scores in our model decreased over time, with a significant interaction between time and gender observed. Conclusion: This study identified longitudinal clinical factors such as greater disease activity, greater functional impairment, and poor global health to be associated with longitudinal depression severity. These factors are potentially modifiable and may help manage depressive symptoms in AS

Repeated Spinal Mobility Measures and Their Association With Radiographic Damage in Ankylosing Spondylitis

Objective: We sought to explore the relationship between changes in repeated mobility measures and spinal structural progression in patients with ankylosing spondylitis (AS) over time. Methods: We studied patients with AS from the PSOAS (Prospective Study of Outcomes in AS) cohort and performed longitudinal multivariable regression modeling to assess the relationship of structural damage measured by their regional (cervical or lumbar) modified Stoke AS Spinal Score(mSASSS) and selected cervical (eg, cervical rotation, lateral bending, and occiput-to-wall distance) and lumbar spinal mobility measures (eg, Schöber’s test and lumbar lateral bending) that were collected at least every 2 years from 2003 to 2019. Results: The median length of follow-up for our 518 patients with cervical mSASSS measurements and 573 with lumbar mSASSS measurements was 4.08 (interquartile range [IQR] 2.25-6.67) and 4.17 (IQR 2.25-6.67) years, respectively. Among the mobility measures, based on multivariable regression models adjusting for clinical/demographic variables and C-reactive protein, we did not observe meaningful associations between changes in spinal mobility with their respective regional mSASSS. Baseline mSASSS, male sex, increased C-reactive protein (CRP), and longer disease duration were associated with increased longitudinal mSASSS in all analyses. Conclusion: Our study shows that 2-year changes in individual spinal mobility measures are not reliably associated with increased, longitudinal, AS-related spinal structural progression. We also confirmed the relationship of baseline mSASSS, sex, CRP, and disease duration with AS-related structural spinal progression over time.</p