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Combined heat and power economic dispatch (CHPED) problem is one of the challenging issues in power system control, and operation, that searches for the optimal values of power and heat generation of different units to minimize the total operation cost. The interdependency of heat and power outputs of CHP units and valve point loading effects of power-only units make this problem very nonlinear and non-convex. So far, a wide variety of optimization algorithms based on simulation of various natural phenomena have been proposed and applied to solve this complex problem, claiming that the proposed algorithm is better than the similar optimization algorithms in terms of accuracy and run-time. In this paper, the CHPED problem is investigated in different case studies by using the imperialist competitive Harris hawks optimization (ICHHO) algorithm, as a combination of the imperialist competitive algorithm and Harris hawks optimization. The effectiveness of the proposed algorithm is first evaluated by testing it on the standard cases of 5, and 7 units as small-scale systems and 48-unit as the large-scale test system, considering the electrical losses. Also for the first time, the multi-zone CHPED (MZCHPED) problem is solved by a metaheuristic algorithm. The obtained results show that ICHHO algorithm reduces the operating costs in the range of 0.02–1.1%, compared to the best-reported results, in different single-zone CHPED (SZCHPED) problems. Also, the MZCHPED results, prove the effective performance of the algorithm compared to the similar SZCHPED problem. [ABSTRACT FROM AUTHOR]

The purpose of this study is to explore existing research on determinants of cervical cancer screening among immigrants and refugees in the U.S. A scoping review was conducted on 77 studies targeting immigrant and/or refugee women in the U.S., investigating factors related to cervical cancer screening. Sixty-three percent of studies were conducted in the past ten years, and included 122,345 women. Studies predominately explored knowledge, beliefs and barriers related to cervical cancer and screening. Common beliefs included fear of cancer, treatment and death. Participants perceived pap smears to be associated with embarrassment, pain and fear. Barriers to screening were reported in three categories: psychosocial (shame and embarrassment), communication (inability to speak in English), and barriers related to access (lack of insurance or primary care provider). Study findings indicate research focused at the individual-level and future research should focus on exploring multilevel influences on cancer screening uptake. [ABSTRACT FROM AUTHOR]

The economic dispatch (ED) is one of the most important short-term problems in power systems, and solving it quickly is essential. However, classical optimization tools are often too computationally demanding to be considered satisfactory. This has motivated the application of metaheuristic methods, which offer a good compromise in terms of solution quality and computation time. However, these methods have been applied in an isolated way and on different problem definitions and case studies, so that there were no clear insights on how they compared to each other. This paper fills this gap by performing an objective comparison of six metaheuristics solving the ED in several case studies under different conditions. Although mixed-integer programming performs best for small case studies, our results confirm that metaheuristics are able to efficiently solve the ED problem. Genetic algorithms emerge as the best performers in terms of solution quality and computation time, followed by PSO and TLBO. [ABSTRACT FROM AUTHOR]