CONTINUOUS SCHEDULING IN CONDITIONS OF MASS WELL CONSTRUCTION. PART 2

In the first part of the work, a model of continuous scheduling of the construction of a group of wells using dedicated labor resources and technical means was described. A multi-stage combinatorial algorithm for finding an effective work schedule based on dynamic programming and aggregation methods is proposed. This part uses a simple numerical example to analyze the practical effectiveness of combinatorial search algorithms depending on the availability of information about the flow rate of new wells. It is characteristic that the calendar plans obtained with the help of software-implemented combinatorial search algorithms are consistent with the generally understood methods of drawing up "manual" schedules. This fact makes it possible to reduce the dimension of combinatorial analysis problems in a controlled way. A multiplicative formula for calculating the well construction time is proposed taking into account its complexity and the skills of the drilling crew. Quantitative performance indicators are formulated that allow the selection of alternative calendar plans. The screening procedure for “clone” solutions using the Hamming distance matrix is described.

The use of intermittent enzalutamide dosing in the treatment of metastatic castrate-resistant prostate cancer.

81 Background: Intermittent hormone manipulation in castrate-sensitive prostate cancer can improve quality of life whilst maintaining comparable disease outcomes with continuous scheduling. Enzalutamide is effective in metastatic castrate-resistant prostate cancer (mCRPC) treatment but can have significant side-effects. We conducted a retrospective analysis of patients treated with intermittent enzalutamide compared with continuous dosing. Methods: Patients prescribed enzalutamide for mCRPC at Royal Cornwall Hospital from September 2011 to February 2018 were included. Data was collected from electronic medical records, selecting patients with at least a 1 month treatment break. Kaplan-Meier analysis of overall survival from enzalutamide start (OS), time to PSA failure (TTF) and total enzalutamide treatment time (TTT) was calculated for intermittent and continuous responders (>50% PSA drop), assigned significance level of 0.05. Results: 243 patients received enzalutamide, 110 (45%) were continuous responders and 29 (12%) had intermittent dosing. All patients treated intermittently had a PSA response prior to first treatment break, which was most commonly for fatigue (60%). 25% were still receiving enzalutamide. Median number of breaks was 1 (range 1-7), time on treatment was 70% and time to first break was 5 months. The intermittent group had significantly improved OS with median not reached, median OS for continuous responders was 19 months (HR 2.39, 95% CI 1.53-3.76, p=0.002). The intermittent group had prolonged TTF (median 13 vs 6 months, p=0.001) and TTT (median 30 vs 10 months, p=0.0003). Conclusions: Intermittent dosing of enzalutamide in these mCRPC patients does not adversely impact OS, increasing time patients remain on treatment. However, this was a small, retrospective, single-centre study; prospective trials are necessary to clarify the role of intermittent enzalutamide.[Table: see text]

Scheduling preemptable jobs on identical processors under varying availability of an additional continuous resource

In this work we consider a problem of scheduling preemptable, independent jobs, characterized by the fact that their processing speeds depend on the amounts of a continuous, renewable resource allocated to jobs at a time. Jobs are scheduled on parallel, identical machines, with the criterion of minimization of the schedule length. Since two categories of resources occur in the problem: discrete (set of machines) and continuous, it is generally called a discrete-continuous scheduling problem. The model studied in this paper allows the total available amount of the continuous resource to vary over time, which is a practically important generalization that has not been considered yet for discrete-continuous scheduling problems. For this model we give some properties of optimal schedules on a basis of which we propose a general methodology for solving the considered class of problems. The methodology uses a two-phase approach in which, firstly, an assignment of machines to jobs is defined and, secondly, for this assignment an optimal continuous resource allocation is found by solving an appropriate mathematical programming problem. In the approach various cases are considered, following from assumptions made on the form of the processing speed functions of jobs. For each case an iterative algorithm is designed, leading to an optimal solution in a finite number of steps.