127 research outputs found
A novel modeling approach for express package carrier planning
Express package carrier networks have large numbers of heavily-interconnected and tightly-constrained resources, making the planning process difficult. A decision made in one area of the network can impact virtually any other area as well. Mathematical programming therefore seems like a logical approach to solving such problems, taking into account all of these interactions. The tight time windows and nonlinear cost functions of these systems, however, often make traditional approaches such as multicommodity flow formulations intractable. This is due to both the large number of constraints and the weakness of the linear programming (LP) relaxations arising in these formulations. To overcome these obstacles, we propose a model in which variables represent combinations of loads and their corresponding routings, rather than assigning individual loads to individual arcs in the network. In doing so, we incorporate much of the problem complexity implicitly within the variable definition, rather than explicitly within the constraints. This approach enables us to linearize the cost structure, strengthen the LP relaxation of the formulation, and drastically reduce the number of constraints. In addition, it greatly facilitates the inclusion of other stages of the (typically decomposed) planning process. We show how the use of templates, in place of traditional delayed column generation, allows us to identify promising candidate variables, ensuring high-quality solutions in reasonable run times while also enabling the inclusion of additional operational considerations that would be difficult if not impossible to capture in a traditional approach. Computational results are presented using data from a major international package carrier. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60965/1/20310_ftp.pd
Emerging Neurotechnologies for Lie Detection and the Fifth Amendment
The article examines the legal implications and advantages of emerging Neurotechnological Lie Detection (NTLD). The self-incrimination clause of the Fifth Amendment to the U.S. Constitution was taken into account, including its scope over NTLD. Key information about the reliability and privacy issues of NTLD is further presented
The Modern Compound Bow
Bows and arrows are ancient weapons that have risen and fallen as the preeminent armaments used by man. Because of the ubiquity of firearms, fatalities from archery injuries in the United States have radically declined. However, when deaths involving this weapon do present themselves, the paucity of reference materials can be a hurdle for forensic pathologists and other forensic scientists. This article will provide a brief history of the origins of the bow and the inception of the compound bow. Comparing and contrasting the structures comprising a traditional bow to those of the modern compound bow will provide insight into how these components function in unison to propel arrows.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141095/1/jfo13503.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141095/2/jfo13503_am.pd
The Difficulties in Assessing Wounds Created by .410 Bore Ammunition and Weapons
When interpreting firearm injuries, the distinction between gunshot wounds and shotgun wounds is important, and separation of these categories is typically straightforward. However, .410 bore firearms can make the classification difficult. Shotguns and revolvers that can fire the same .410 bore ammunition are readily available. This study investigates the soot and gunpowder deposits and pellet patterning of these two types of weapons using cartridges specially designed for .410 bore revolvers and standard birdshot pellet ammunition. For both ammunition types, the revolver had more prompt pellet dispersion and positive detection of gunpowder at greater distances compared to the shotgun. Additionally, .410 bore slugs are of similar caliber to many common bullets. In comparing the .410 bore slugs to equivalent bullets, some morphologic differences may be imparted on the skin by the slugs, but the greatest insight into the weapon remained with the retained projectiles.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154370/1/jfo14181.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154370/2/jfo14181_am.pd
Recommended from our members
Mixed fleet dispatching in truckload relay network design optimization
We propose a mathematical formulation for strategic relay network design and dispatching method selection for full truckload transportation. The proposed model minimizes total transportation and installation costs of a mixed fleet dispatching system combining relay network and point-to-point dispatching. Operational constraints such as maximum driver tour length and load circuity are considered within the variable definition using predefined templates to generate feasible routes. High quality solutions for largely-sized problem instances are obtained in reasonable times. Computational results are analyzed to develop insights about the mixed fleet dispatching system and quantify its benefits over relay network-only and point-to-point dispatching.This is the author's version of a work that was accepted for publication in Transportation Research Part E. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Transportation Research Part E, 54 (2013), pp. 32-49 DOI information: 10.1016/j.tre.2013.04.001Keywords: Truckload trucking, Dispatching, Mixed fleet, Composite variable, Relay network designKeywords: Truckload trucking, Dispatching, Mixed fleet, Composite variable, Relay network desig
Recommended from our members
Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA
Because of their unique physiology, lichen communities are highly sensitive to climatic conditions, making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for tracking the effects of climate change in south-central and southeast Alaska. Using 196 plots, we model community composition and 12 individual species abundances in relation to synthetic climate variables. Both types of lichen indicator are closely related to the climate variable describing a transition from warm, wet oceanic climates to cooler, drier suboceanic climates. Lichen communities and individual species exhibited thresholds associated with average December minimum temperatures between –10.2 and –7.8°C and annual precipitation between 106 and 172 cm, suggesting rapid turnover with relatively small changes within these
ranges. These climate conditions occur close to the coast in northern portions of the region and further inland in southeast Alaska. Because lichen communities in the threshold region may be most sensitive to a changing future climate, they should be targeted for monitoring efforts.Keywords: epiphytes, community analysis, Alaska, climate, threshold
Delirium Education for Family Caregivers of Patients in the Intensive Care Unit: A Pilot Study
Objectives Delirium, an acute change in mental state, seen in hospitalized older adults is a growing public health concern with implications for both patients and caregivers; however, there is minimal research on educating caregivers about delirium. Utilizing family caregivers to assist with delirium management in acute care settings demonstrates improved health outcomes supporting the need for patient and family centered care. The primary aims of the study were to determine feasibility of implementing a delirium education video for caregivers of patients in an adult oncology intensive care unit and compare delirium knowledge to caregivers in a control group. Methods A quasi-experimental design comprised of 31 family caregivers of adult patients in an oncology intensive care unit to determine feasibility of implementing a delirium education video. Results The results demonstrate feasibility of implementing a caregiver education video in-person and virtually. While total delirium knowledge scores were not statistically significant, knowledge gained within the delirium presentation subgroup was significant (p = .05). Conclusion This study demonstrates feasibility of implementing a caregiver education video and findings support further research in this area. Innovation
Collaborating with caregivers to develop virtual video education for delirium allows for a versatile approach to connect with caregivers to support their caregiving role
Integration of the Load Matching and Routing Problem with Equipment Balancing for Small Package Carriers
Small package delivery is a multi-billion dollar industry with complex planning decisions required to efficiently utilize costly resources and meet tight time requirements. The planning process is typically decomposed into sequential subproblems to establish tractability. This decomposition can greatly degrade solution quality. In this paper, we therefore consider the integration of two closely related key sub-problems: load matching and routing, and equipment balancing. First, we identify critical challenges faced in trying to solve these problems. Then, we present a novel modeling approach to address these challenges. Finally, we conclude with computational results from UPS, the world’s largest package delivery company, demonstrating an improvement of approximately 5% over their existing methods for solving this pair of problems
Influenza A virus surveillance, infection and antibody persistence in snow geese (Anser caerulescens)
Some snow geese (Anser caerulescens) migrate between Eurasia and North America and exhibit high seroprevalence for influenza A viruses (IAVs). Hence, these birds might be expected to play a role in intercontinental dispersal of IAVs. Our objective in this manuscript was to characterize basic incidence and infection characteristics for snow geese to assess whether these birds are likely to significantly contribute to circulation of IAVs. Thus, we 1) estimated snow goose infection prevalence by summarizing \u3e 5,000 snow goose surveillance records, 2) experimentally infected snow geese with a low pathogenic IAV (H4N6) to assess susceptibility and infection dynamics and 3) characterized long-term antibody kinetics. Infection prevalence based on surveillance data for snow geese was 7.88%, higher than the infection rates found in other common North American goose species. In the experimental infection study, only 4 of 7 snow geese shed viral RNA. Shedding in infected birds peaked at moderate levels (mean peak 102.62 EID50 equivalents/mL) and was exclusively associated with the oral cavity. Serological testing across a year post-exposure showed all inoculated birds seroconverted regardless of detectable shedding. Antibody levels peaked at 10 days post-exposure and then waned to undetectable levels by 6 months. In sum, while broad-scale surveillance results showed comparatively high infection prevalence, the experimental infection study showed only moderate susceptibility and shedding. Consequently, additional work is needed to assess whether snow geese might exhibit higher levels of susceptibility and shedding rates when exposed to other IAV strains
- …