Inventory Optimization Using a SimPy Simulation Model

Existing multi-echelon inventory optimization models and formulas were studied to get an understanding of how safety stock levels are determined. Because of the restrictive distribution assumptions of the existing safety stock formula, which are not necessarily realistic in practice, a method to analyze the performance of this formula in a more realistic setting was desired. A SimPy simulation model was designed and implemented for a simple two-stage supply chain as a way to test the performance of the safety stock formula. This implementation produced results which led to the conclusion that the safety stock formula tends to underestimate the level of safety stock needed to provide a certain service level when predicted standard deviation of demand is underestimated and the assumptions of normally distributed demand and normally distributed lead times are not fulfilled

Impact of Mesh Tracks and Low-Ground-Pressure Vehicle Use on Blanket Peat Hydrology

No abstract available

Does the Composition of Dissolved Organic Carbon (DOC) in Peatland Streams Reflect the DOC Leached from Vegetation, Litter and Soil?

No abstract available

Identifying reducible k-tuples of vectors with subspace-proximity sensitive hashing/filtering

We introduce and analyse a family of hash and predicate functions that are more likely to produce collisions for small reducible configurations of vectors. These may offer practical improvements to lattice sieving for short vectors. In particular, in one asymptotic regime the family exhibits significantly different convergent behaviour than existing hash functions and predicates.Comment: 20 pages, 5 figure

The Hereditary Approach to Time Dependent Modeling with Fractional Exponential Function

For polymer based composites, the creep and relaxation parameters are examined using the hereditary approach to time dependent mechanical behavior. Specifically, methods of optimization are utilized to determine the optimal parameter estimates for the fractional exponential functions. The relative advantages of the Rabatnov kernel over the Abel kernel have been examined. Finally, the results of this parameter estimation using the Rabatnov kernel (i.e. fractional exponential) are compared to results obtained from experimental data

The Chain Rule Does Not Have to be a Pain Rule

Relational and instrumental understanding of the Chain Rule can help teachers provide students a deeper and more meaningful calculus experience

Does the Composition of Dissolved Organic Carbon (DOC) in Peatland Streams Reflect the DOC Leached from Vegetation, Litter and Soil?

No abstract available

Three Super-Earths Orbiting HD 7924

We report the discovery of two super-Earth mass planets orbiting the nearby K0.5 dwarf HD 7924 which was previously known to host one small planet. The new companions have masses of 7.9 and 6.4 M$_\oplus$, and orbital periods of 15.3 and 24.5 days. We perform a joint analysis of high-precision radial velocity data from Keck/HIRES and the new Automated Planet Finder Telescope (APF) to robustly detect three total planets in the system. We refine the ephemeris of the previously known planet using five years of new Keck data and high-cadence observations over the last 1.3 years with the APF. With this new ephemeris, we show that a previous transit search for the inner-most planet would have covered 70% of the predicted ingress or egress times. Photometric data collected over the last eight years using the Automated Photometric Telescope shows no evidence for transits of any of the planets, which would be detectable if the planets transit and their compositions are hydrogen-dominated. We detect a long-period signal that we interpret as the stellar magnetic activity cycle since it is strongly correlated with the Ca II H and K activity index. We also detect two additional short-period signals that we attribute to rotationally-modulated starspots and a one month alias. The high-cadence APF data help to distinguish between the true orbital periods and aliases caused by the window function of the Keck data. The planets orbiting HD 7924 are a local example of the compact, multi-planet systems that the Kepler Mission found in great abundance.Comment: Accepted to ApJ on 4/7/201

Introduction to the special issue : From RIDGE to Ridge 2000

Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, no. 1 (2012): 12–17, doi:10.5670/oceanog.2012.01.Articles in this special issue of Oceanography represent a compendium of research that spans the disciplinary and thematic breadth of the National Science Foundation's Ridge 2000 Program, as well as its geographic focal points. The mid-ocean ridge (MOR) crest is where much of Earth's volcanism is focused and where most submarine volcanic activity occurs. If we could look down from space at our planet with the ocean drained, the MOR's topography and shape, along with its intervening fracture zones, would resemble the seams on a baseball, with the ocean basins dominating our planetary panorama. The volcanic seafloor is hidden beneath the green-blue waters of the world's ocean, yet therein lie fundamental clues to how our planet works and has evolved over billions of years, something that was not clearly understood 65 years ago—witness the following quote from H.H. Hess (1962) in his essay on "geopoetry" and commentary on J.H.F. Umbgrove's (1947) comprehensive summary of Earth and ocean history: The birth of the oceans is a matter of conjecture, the subsequent history is obscure, and the present structure is just beginning to be understood. Fascinating speculation on these subjects has been plentiful, but not much of it predating the last decade [the 1950s] holds water.This special issue was funded by a supplement to the Ridge 2000 Office grant at the Woods Hole Oceanographic Institution (NSF-OCE-0838923)

The public perception of the facilitators and barriers to implementing personalized medicine: a systematic review

The integration of personalized medicine (PM) into mainstream healthcare will only be successful if the public understands and supports this change. The aim was to understand the public perception of the barriers and facilitators towards the use of PM. A systematic review of the literature was conducted within six databases from 2006 to 2018. Twenty-one studies with 9507 participants were included. The key themes were familiarity andwillingness to use PM, perceived benefits and perceived risks of PM. The review shows that the public is generally enthusiastic about the introduction of PM, although this should be interpreted with cautious optimism due to participants having a limited familiarity of the underlying principles of PM. The study defines areas where progress can be made to enhance this understanding and addresses legitimate concerns