An Adaptive Surrogate-Assisted Particle Swarm Optimization for Expensive Problems

To solve engineering problems with evolutionary algorithms, many expensive objective function evaluations (FEs) are required. To alleviate this difficulty, the surrogate-assisted evolutionary algorithm (SAEA) has attracted increasingly more attention in both academia and industry. The existing SAEAs depend on the quantity and quality of the original samples, and it is difficult for them to yield satisfactory solutions within the limited number of FEs. Moreover, these methods easily fall into local optima as the dimension increases. To address these problems, this paper proposes an adaptive surrogate-assisted particle swarm optimization (ASAPSO) algorithm. In the proposed algorithm, an adaptive surrogate selection method that depends on the comparison between the best existing solution and the latest obtained solution is suggested to ensure the effectiveness of the optimization operations and improve the computational efficiency. Additionally, a model output criterion based on the standard deviation is suggested to improve the robustness and stability of the ensemble model. To verify the performance of the proposed algorithm, 10 benchmark functions with different modalities from 10 to 50 dimensions are tested, and the results are compared with those of five state-of-the-art SAEAs. The experimental results indicate that the proposed algorithm performs well for most benchmark functions within the limited number of FEs. The performance of the proposed algorithm in solving engineering problems is verified by applying the algorithm to the PX oxidation process.

The capacity to designate a surrogate is distinct from decisional capacity: normative and empirical considerations

The capacity to designate a surrogate (CDS) is not simply another kind of medical decision-making capacity (DMC). A patient with DMC can express a preference, understand information relevant to that choice, appreciate the significance of that information for their clinical condition, and reason about their choice in light of their goals and values. In contrast, a patient can possess the CDS even if they cannot appreciate their condition or reason about the relative risks and benefits of their options. Patients who lack DMC for many or most kinds of medical choices may nonetheless possess the CDS, particularly since the complex means-ends reasoning required by DMC is one of the first capacities to be lost in progressive cognitive diseases (eg, Alzheimer’s disease). That is, patients with significant cognitive decline or mental illness may still understand what a surrogate does, express a preference about a potential surrogate, and be able to provide some kind of justification for that selection. Moreover, there are many legitimate and relevant rationales for surrogate selection that are inconsistent with the reasoning criterion of DMC. Unfortunately, many patients are prevented from designating a surrogate if they are judged to lack DMC. When such patients possess the CDS, this practice is ethically wrong, legally dubious and imposes avoidable burdens on healthcare institutions.

Effect of pH on the Electrophoretic Mobility of Spores of Bacillus anthracis and Its Surrogates in Aqueous Solutions

ABSTRACTThe electrophoretic mobility (EPM) of endospores ofBacillus anthracisand surrogates was measured in aqueous solution across a broad pH range and several ionic strengths. EPM values trended around phylogenetic clustering based on the 16S rRNA gene. Measurements reported here provide new insight forBacillus anthracissurrogate selection and for attachment/detachment and transport studies.