Computing Near-Optimal Solutions to the Steiner Problem in a Graph Using a Genetic Algorithm

A new Genetic Algorithm (GA) for the Steiner Problem in a Graph (SPG) is presented. The algorithm is based on a bitstring encoding. A bitstring specifies selected Steiner vertices and the corresponding Steiner tree is computed using the Distance Network Heuristic. This scheme ensures that every bitstring correspond to a valid Steiner tree and thus eliminates the need for penalty terms in the cost function. The GA is tested on all SPG instances from the OR-Library of which the largest graphs have 2,500 vertices and 62,500 edges. When executed 10 times on each of 58 graph examples, the GA finds the global optimum at least once for 55 graphs and every time for 43 graphs. In total the GA finds the global optimum in 77 % of all program executions and is within 1 % from the global optimum in more than 92 % of all executions. The performance is compared to that of two branch-and-cut algorithms and one of the very best deterministic heuristics, an iterated version of the Shortest Path Heuristic (SPH-I). For all test examples but one, even the worst result ever found by the GA is equal to or better than the result of SPH-I and in many cases the average error ratio of the GA is an order of magnitude better than that of SPH-I. The runtime of the GA is moderate for all test examples. This is in contrast to SPH-I as well as the branch-and-cut algorithms, for which the runtime in some cases are extremely high

Severity of fatigue in people with rheumatoid arthritis, psoriatic arthritis and spondyloarthritis:Results of a cross-sectional study

BACKGROUND:Despite improvements in treatment for rheumatoid arthritis (RA), psoriatic arthritis (PsA) and spondyloarthritis (axSpA), several key unmet needs remain, such as fatigue. The objective of this study was to describe the severity of fatigue, disease characteristics and socioeconomic factors in people with RA, PsA and axSpA. METHODS:The study was designed as a cross-sectional survey collecting patient characteristics such as disease characteristics, socioeconomic factors and fatigue in people with RA, PsA and axSpA in Denmark. Respondents were consecutively recruited for the study over a six-month period in 2018 via routine visits to outpatient rheumatology clinics. Study nurses collected information on diagnosis, current disease-related treatment and disease activity from medical journals. People were invited to complete a questionnaire related to socioeconomic factors and containing the FACIT-Fatigue subscale. Descriptive statistics were analyzed using SAS. RESULTS:We invited 633 people to participate, and 488 (77%) completed the questionnaire. Women constituted 62% of respondents, and the mean age was 53.5 years. Respondents had on average been diagnosed between 11 and 15 years ago. Overall, 79% had no changes to their disease-related treatment during the past year, and the average disease activity as indicated by DAS28 for RA and PsA was 2.48 and 2.36, respectively, and BASDAI for axSpA was 28.40. Fatigue was present in all three diagnoses (mean: 34.31). The mean fatigue score varied from respondents answering that they suffered from no or little fatigue (mean: 45.48) to extreme fatigue (mean: 10.11). Analyses demonstrated that the respondents were not considerably different from nonrespondents, and the study population is considered representative compared with Danish RA and axSpA patients in the Danish National Rheumatology Registry, the DANBIO database. CONCLUSION:We found that the majority of the study population were fatigued (61%). They had low disease activity and few disease-related treatment changes

Protocol for evaluating and implementing a pragmatic value-based healthcare management model for patients with inflammatory arthritis:A Danish population-based regional cohort and qualitative implementation study

Introduction The provision of healthcare for patients with inflammatory arthritis occurs in the context of somewhat conflicting targets, values and drivers. Therefore, there is a need for introducing 'value-based healthcare' defined as the value of patient relevant health outcomes in relation to costs. This term is a central part of tomorrow's healthcare sector, especially for rheumatic diseases, yet the transition is a huge challenge, as it will impact the development, delivery and assessment of healthcare. Aims The aim of this study is to compare medical and patient evaluated impact of the traditional settlement and financing production (DAGS) controlled healthcare setting with a value-based and patient-centred adjunctive to standard care. Methods and analysis Patients with inflammatory arthritis receiving treatment in routine care at the outpatient clinics in the Capital Region of Denmark will prospectively and consecutively be enrolled in a Non-Intervention-Study framework providing a pragmatic value-based management model. A Danish reference cohort, used for comparison will be collected as part of routine clinical care. The enrolment period will be from 1 June 2018 until 31December 2023. Baseline and follow-up visits will be according to routine clinical care. Registry data will be obtained directly from patients and include personal, clinical and outcomes information. The study results will be reported in accordance with the STROBE statement. Ethics and dissemination The study has been notified to the Danish Data Protection Agency and granted authorisation for the period June 2018 to January 2025 (pending). Informed consent will be obtained from all patients before enrolment in the study. The study is approved by the ethics committee, Capital Region of Denmark (H-18013158). Results of the study will be disseminated through publication in international peer-reviewed journals

NIR Monitoring of Ammonia in Anaerobic Digesters Using a Diffuse Reflectance Probe

The feasibility of using a diffuse reflectance probe attached to a near infrared spectrometer to monitor the total ammonia nitrogen (TAN) content in an anaerobic digester run on cattle manure was investigated; as a previous study has indicated that this probe can be easily attached to an anaerobic digester. Multivariate modelling techniques such as partial least squares regression and interval partial least squares methods were used to build models. Various data pre-treatments were applied to improve the models. The TAN concentrations measured were in the range of 1.5 to 5.5 g/L. An R2 of 0.91 with an RMSEP of 0.32 was obtained implying that the probe could be used for monitoring and screening purposes

Perspectives on ethnic and racial disparities in Alzheimer\u27s disease and related dementias: Update and areas of immediate need

Alzheimer\u27s disease and related dementias (ADRDs) are a global crisis facing the aging population and society as a whole. With the numbers of people with ADRDs predicted to rise dramatically across the world, the scientific community can no longer neglect the need for research focusing on ADRDs among underrepresented ethnoracial diverse groups. The Alzheimer\u27s Association International Society to Advance Alzheimer\u27s Research and Treatment (ISTAART; alz.org/ISTAART) comprises a number of professional interest areas (PIAs), each focusing on a major scientific area associated with ADRDs. We leverage the expertise of the existing international cadre of ISTAART scientists and experts to synthesize a cross-PIA white paper that provides both a concise “state-of-the-science” report of ethnoracial factors across PIA foci and updated recommendations to address immediate needs to advance ADRD science across ethnoracial populations. © 2018 The Author

Placement and global routing of VLSI macro-Cell layouts using genetic algorithms

The topic of this Ph.D. thesis is the application of evolution-based algorithms (EAs) to various highly constrained combinatorial optimization problems arising in layout synthesis of VLSI integrated circuits. The purpose is to investigate which performance can be obtained by EAs compared to traditional methods, to identify strengths and weaknesses of EAs within this application domain and to identify possible EA design principles yielding the best performance.In particular, the study focuses on genetic algorithms (GAs) for placement and global routing of macro-cell layouts. GAs for the these problems are developed, and their performance compared to that of existing state-of-the-art tools, in terms of absolute solution quality and absolute runtime. The main results are new GAs for both macro-cell placement and global routing, which are comparable to or better than the current state-of-the-art approaches. Especially, a GA for the Steiner problem in a graph is presented, which to our knowledge is the current best heuristic for this problem, in terms of solution quality as well as runtime.Finally, various design principles significantly affecting algorithm performance are identified, of which the constraint handling method is of utmost importance. Within the application domain considered, enforcing constraint satisfaction at all times is found to consistently outperform methods based on penalty terms

Genetic Algorithms in Computer Aided Design of Integrated Circuits

An increasing number of successful applications of Genetic Algorithms (GAs) within Computer Aided Design (CAD) of Integrated Circuits (ICs) is reported in the literature. The problems dealt with in this field consist of sequences of sub-problems, which are characterized by being NP-hard, large and mutually dependent. This very high level of complexity should make the GA a well suited approach, at least in principle. However, the GA is of practical interest to the CAD community if and only if it is competitive to the existing approaches with respect to performance. With this fact as the starting point, the purpose of this paper is to discuss how to develop high-performance GAs for CAD of ICs. After reviewing a number of recent, performance competitive GAs for key problems in CAD of ICs, the common characteristics of these algorithms are discussed. They all exploit problem specific knowledge in various ways or are integrated with other heuristics. The paper also discusses performance eva..