Mainstream research in priority dispatching has considered jobs with equal delay penalties, thereby ruling out strategic differentiation of customer orders. We develop and test efficient dispatching rules for the weighted tardiness problem with job-specific due dates and delay penalties. Our approach builds on previous greedy heuristics which assign the priority on the basis of the expected tardiness cost per immediate processing requirements. In multi-machine applications, estimates of the remaining leadtime are needed to determine local operation due dates and to evaluate the adequacy of the job's slack. Two slightly different "look-ahead" features are identified, and the corresponding priority rules are tested in job shop experiments with a variety of load conditions. The results indicate that the new rules are not only superior to competing rules for minimizing weighted tardiness penalties but are also robust for several other criteria, such as the number of tardy jobs and the costs of in-process inventories.production/scheduling, job shop, deterministic

Increasing product complexity, manufacturing environment complexity and an increased emphasis on product quality are all factors leading to uncertainties in production processes. These uncertainties are in the form of unplanned machine maintenance, varying production yields and rework, among others. In planning for production, an adequate model must incorporate these uncertainties into the representation of the production process. This paper treats the aggregate planning problem for a single product with random demand and random capacity. In the single-period problem, random capacity does not affect the optimal policy but results in a unimodal, nonconvex cost function. In the multiple-period and infinite-horizon settings order-up-to policies that are dependent on the distribution of capacity are shown to be optimal in spite of a nonconvex cost. In the infinite-horizon setting an intuitive description of the situation leads to the notion of a class of extended myopic policies, requiring the consideration of review periods of uncertain length.

We examine the problem of scheduling a given set of jobs on a single machine to minimize total early and tardy costs. Two dispatch priority rules are proposed and tested for this NP-complete problem. These were found to perform far better than known heuristics that ignored early costs. For situations where the potential cost savings are sufficiently high to justify more sophisticated techniques, we propose a variation of the Beam Search method developed by researchers in artificial intelligence. This variant, called Filtered Beam Search, is able to use priority functions to search a number of solution paths in parallel. A computational study showed that this search method was not only efficient but also consistent in providing near-optimal solutions with a relatively small search tree. The study also includes an investigation of the impacts of Beam Search parameters on three variations of Beam Search for this problem.production/scheduling, deterministic job shop, single stage

No abstract

EB, Yin DP. Activation of bile acid signaling improves metabolic phenotypes in high-fat diet-induced obese mice. Am J Physiol Gastrointest Liver Physiol 311: G286 -G304, 2016. First published June 23, 2016 doi:10.1152/ajpgi.00202.2016.-The metabolic benefits induced by gastric bypass, currently the most effective treatment for morbid obesity, are associated with bile acid (BA) delivery to the distal intestine. However, mechanistic insights into BA signaling in the mediation of metabolic benefits remain an area of study. The bile diversion () mouse model, in which the gallbladder is anastomosed to the distal jejunum, was used to test the specific role of BA in the regulation of glucose and lipid homeostasis. Metabolic phenotype, including body weight and composition, glucose tolerance, energy expenditure, thermogenesis genes, total BA and BA composition in the circulation and portal vein, and gut microbiota were examined. BD improves the metabolic phenotype, which is in accord with increased circulating primary BAs and regulation of enterohormones. BD-induced hypertrophy of the proximal intestine in the absence of BA was reversed by BA oral gavage, but without influencing BD metabolic benefits. BD-enhanced energy expenditure was associated with elevated TGR5, D2, and thermogenic genes, including UCP1, PRDM16, PGC-1␣, PGC-1␤, and PDGFR␣ in epididymal white adipose tissue (WAT) and inguinal WAT, but not in brown adipose tissue. BD resulted in an altered gut microbiota profile (i.e., Firmicutes bacteria were decreased, Bacteroidetes were increased, and Akkermansia was positively correlated with higher levels of circulating primary BAs). Our study demonstrates that enhancement of BA signaling regulates glucose and lipid homeostasis, promotes thermogenesis, and modulates the gut microbiota, which collectively resulted in an improved metabolic phenotype. bile acids; bile diversion; obesity; energy expenditure; gut microbiota; gastric bypass; mice