Cable Tree Wiring -- Benchmarking Solvers on a Real-World Scheduling Problem with a Variety of Precedence Constraints

Cable trees are used in industrial products to transmit energy and information between different product parts. To this date, they are mostly assembled by humans and only few automated manufacturing solutions exist using complex robotic machines. For these machines, the wiring plan has to be translated into a wiring sequence of cable plugging operations to be followed by the machine. In this paper, we study and formalize the problem of deriving the optimal wiring sequence for a given layout of a cable tree. We summarize our investigations to model this cable tree wiring Problem (CTW) as a traveling salesman problem with atomic, soft atomic, and disjunctive precedence constraints as well as tour-dependent edge costs such that it can be solved by state-of-the-art constraint programming (CP), Optimization Modulo Theories (OMT), and mixed-integer programming (MIP) solvers. It is further shown, how the CTW problem can be viewed as a soft version of the coupled tasks scheduling problem. We discuss various modeling variants for the problem, prove its NP-hardness, and empirically compare CP, OMT, and MIP solvers on a benchmark set of 278 instances. The complete benchmark set with all models and instance data is available on github and is accepted for inclusion in the MiniZinc challenge 2020

Gender differences in the use of cardiovascular interventions in HIV-positive persons; the D:A:D Study

Peer reviewe

Mobilizing agencies for incidence surveys on child maltreatment: successful participation in Switzerland and lessons learned

Abstract Background Many countries around the world lack data on the epidemiology of agency response to child maltreatment. They therefore lack information on how many children in need get help and protection or if children stand equal chances across regions to get services. However, it has proven difficult to commit child protection agencies to participation in incidence studies. Methods The Optimus Study invested in a continuous collaborative effort between research and practice to develop a data collection for the first national study on the incidence of agency responses to all forms of child maltreatment in Switzerland. An innovative approach of utilizing individual agencies’ standardized data reduced work burden for participation respectably: any arbitrary excerpt of data on new cases between September 1 and November 30, 2016, could be uploaded to a secured web-based data integration platform. It was then mapped automatically to fit the study’s definitions and operationalizations. Results This strategy has led to a largely successful participation rate of 76% of agencies in the nationwide sample. 253 agencies from the social and health sector, public child protection, and the penal sector have provided data. Conclusions Valuing agencies context-specific knowledge and expertise instead of viewing them as mere providers of data is a precondition for representativeness of incidence data on agency responses to child maltreatment. Potential investigators of future similar studies might benefit from the lessons learned of the presented project

Risk for non-AIDS-defining and AIDS-defining cancer of early versus delayed initiation of antiretroviral therapy: A multinational prospective cohort study

Background: Immediate initiation of antiretroviral therapy (ART) regardless of CD4 cell count reduces risk for AIDS and non-AIDS-related events in asymptomatic, HIV-positive persons and is the standard of care. However, most HIV-positive persons initiate ART when their CD4 count decreases below 500 × 109 cells/L. Consequences of delayed ART on risk for non-AIDS-defining and AIDS-defining cancer, one of the most common reasons for death in HIV, are unclear. Objective: To estimate the long-term risk difference for cancer with the immediate ART strategy. Design: Multinational prospective cohort study. Setting: The D:A:D (Data collection on Adverse events of anti-HIV Drugs) study, which included HIV-positive persons from Europe, Australia, and the United States. Participants: 8318 HIV-positive persons with at least 1 measurement each of CD4 cell count and viral load while ART-naive (study period, 2006 to 2016). Measurements: The parametric g-formula was used, with adjustment for baseline and time-dependent confounders (CD4 cell count and viral load), to assess the 10-year risk for non-AIDS-defining and AIDS-defining cancer of immediate versus deferred (at CD4 counts < 350 and < 500 × 109 cells/L) ART initiation strategies. Results: During 64 021 person-years of follow-up, 231 cases of non-AIDS-defining cancer and 272 of AIDS-defining cancer occurred among HIV-positive persons with a median age of 36 years (interquartile range, 29 to 43 years). With immediate ART, the 10-year risk for non-AIDS-defining cancer was 2.97% (95% CI, 2.37% to 3.50%) and that for AIDS-defining cancer was 2.50% (CI, 2.37% to 3.38%). Compared with immediate ART initiation, the 10-year absolute risk differences when deferring ART to CD4 counts less than 500 × 109 cells/L and less than 350 × 109 cells/L were 0.12 percentage point (CI, -0.01 to 0.26 percentage point) and 0.29 percentage point (CI, -0.03 to 0.73 percentage point), respectively, for non-AIDS-defining cancer and 0.32 percentage point (CI, 0.21 to 0.44 percentage point) and 1.00 percentage point (CI, 0.67 to 1.44 percentage points), respectively, for AIDS-defining cancer. Limitation: Potential residual confounding due to observational study design. Conclusion: In this young cohort, effects of immediate ART on 10-year risk for cancer were small, and further supportive data are needed for non-AIDS-defining cancer. Primary Funding Source: Highly Active Antiretroviral Therapy Oversight Committee