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Conventionally, job processing times are assumed to be constant from the first job to be processed until the last job to be completed. However, recent empirical studies in several industries have verified that unit costs decline as firms produce more of a product and gain knowledge or experience. This phenomenon is known as the “learning effect.” This paper(More)
This paper addresses a bi-criteria two-machine flowshop scheduling problem when the learning effect is present. The objective is to find a sequence that minimizes a weighted sum of the total completion time and the maximum tardiness. In this article, a branch-and-bound method, incorporating several dominance properties and a lower bound, is presented to(More)
BACKGROUND Identification of patients at risk of death from cancer surgery should aid in preoperative preparation. The purpose of this study is to assess and adjust the age-adjusted Charlson comorbidity index (ACCI) to identify cancer patients with increased risk of perioperative mortality. METHODS We identified 156,151 patients undergoing surgery for one(More)
The utility of lymph node ratio (LNR) in predicting outcomes has been reported previously. In current study, we further subgroup by LNR in subjects with lymph nodes metastasis of colorectal cancer, breast cancer, and head and neck cancer. Cancers with pathological lymph node metastasis (pN+) at time of diagnosis between 2004 and 2012 were identified from(More)
We studied the effect of Age-Adjusted Comorbidity Index Score in colorectal cancer patients who underwent similarly aggressive treatment. Using the National Health Insurance Research Database of Taiwan, we identified 5643 patients with colorectal cancer who underwent surgical resection and chemoradiation from 2007 through 2011. We estimated survival(More)