Robustness and Adaptability Analysis of Future Military Air Transportation Fleets

Making decisions about the structure of a future military fleet is challenging. Several issues need to be considered, including multiple competing objectives and the complexity of the operating environment. A particular challenge is posed by the various types of uncertainty that the future holds. It is uncertain what future events might be encountered and how fleet design decisions will influence these events. In order to assist strategic decision-making, an analysis of future fleet options needs to account for conditions in which these different uncertainties are exposed. It is important to understand what assumptions a particular fleet is robust to, what the fleet can readily adapt to, and what conditions present risks to the fleet. We call this the analysis of a fleet’s strategic positioning. Our main aim is to introduce a framework that captures information useful to a decision maker and defines the concepts of robustness and adaptability in the context of future fleet design. We demonstrate our conceptual framework by simulating an air transportation fleet problem. We account for uncertainty by employing an explorative scenario-based approach. Each scenario represents a sampling of different future conditions and different model assumptions. Proposed changes to a fleet are then analysed based on their influence on the fleet’s robustness, adaptability, and risk to different scenarios

Network Topology and Time Criticality Effects in the Modularised Fleet Mix Problem

In this paper, we explore the interplay between network topology and time criticality in a military logistics system. A general goal of this work (and previous work) is to evaluate land transportation requirements or, more specifically, how to design appropriate fleets of military general service vehicles that are tasked with the supply and re-supply of military units dispersed in an area of operation. The particular focus of this paper is to gain a better understanding of how the logistics environment changes when current Army vehicles with fixed transport characteristics are replaced by a new generation of modularised vehicles that can be configured task-specifically. The experimental work is conducted within a well developed strategic planning simulation environment which includes a scenario generation engine for automatically sampling supply and re-supply missions and a multi-objective meta-heuristic search algorithm (i.e. Evolutionary Algorithm) for solving the particular scheduling and routing problems. The results presented in this paper allow for a better understanding of how (and under what conditions) a modularised vehicle fleet can provide advantages over the currently implemented system

A State Of Necessity: IUU Fishing In The CCAMLR Zone

Throughout the world, overexploitation threatens the future viability of many fish stocks. This threat extends to the most remote areas on earth, including the Southern Ocean—that vast body of water surrounding the Antarctic continent. Indeed, the geographic isolation of the Antarctic is no longer an insurmountable barrier to the large-scale exploitation of fish stocks in that region. The Southern Ocean, however, is not without regulatory structure. The Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR, or The Convention, or Convention), a treaty that aims to achieve sustainable exploitation of marine stocks in the Antarctic, is the primary international instrument that applies to living resources in the Southern Ocean. The institutional bodies formed under CCAMLR act as a regional management regime that enacts conservation measures to ensure the sustainable use of Antarctic marine species. This management regime, however, faces its own difficulties. In particular, CCAMLR’s effectiveness is threatened by continued illegal, unreported and unregulated (IUU) fishing in the Southern Ocean region. The problem is particularly prevalent in the Antarctic, because a large part of the area constitutes high seas, thereby allowing states to fish freely under international law. Another factor contributing to the IUU problem is that CCAMLR conservation measures on the high seas do not apply to countries who are not parties to the treaty (non-party states). This article will outline the weaknesses in the CCAMLR regime and weaknesses in other international instruments in dealing with the IUU problem. It will also discuss applicable defenses that a state may raise in the event that it decides to take direct action against IUU fishing vessels in the high seas of the Southern Ocean, thereby exposing itself to potential liability under international law. One such defense is to claim a “state of necessity” that makes it imperative for a CCAMLR party state to take action in breach of international law. This paper will examine whether the dire threat to the Antarctic ecosystem posed by IUU fishing could sustain such a defense. Finally, this paper will consider the consequences of a defense of necessity and whether this would be an effective means to combat IUU fishing

A State Of Necessity: IUU Fishing In The CCAMLR Zone

Throughout the world, overexploitation threatens the future viability of many fish stocks. This threat extends to the most remote areas on earth, including the Southern Ocean—that vast body of water surrounding the Antarctic continent. Indeed, the geographic isolation of the Antarctic is no longer an insurmountable barrier to the large-scale exploitation of fish stocks in that region. The Southern Ocean, however, is not without regulatory structure. The Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR, or The Convention, or Convention), a treaty that aims to achieve sustainable exploitation of marine stocks in the Antarctic, is the primary international instrument that applies to living resources in the Southern Ocean. The institutional bodies formed under CCAMLR act as a regional management regime that enacts conservation measures to ensure the sustainable use of Antarctic marine species. This management regime, however, faces its own difficulties. In particular, CCAMLR’s effectiveness is threatened by continued illegal, unreported and unregulated (IUU) fishing in the Southern Ocean region. The problem is particularly prevalent in the Antarctic, because a large part of the area constitutes high seas, thereby allowing states to fish freely under international law. Another factor contributing to the IUU problem is that CCAMLR conservation measures on the high seas do not apply to countries who are not parties to the treaty (non-party states). This article will outline the weaknesses in the CCAMLR regime and weaknesses in other international instruments in dealing with the IUU problem. It will also discuss applicable defenses that a state may raise in the event that it decides to take direct action against IUU fishing vessels in the high seas of the Southern Ocean, thereby exposing itself to potential liability under international law. One such defense is to claim a “state of necessity” that makes it imperative for a CCAMLR party state to take action in breach of international law. This paper will examine whether the dire threat to the Antarctic ecosystem posed by IUU fishing could sustain such a defense. Finally, this paper will consider the consequences of a defense of necessity and whether this would be an effective means to combat IUU fishing

Parametric hazard rate models for long-term sickness absence

PURPOSE: In research on the time to onset of sickness absence and the duration of sickness absence episodes, Cox proportional hazard models are in common use. However, parametric models are to be preferred when time in itself is considered as independent variable. This study compares parametric hazard rate models for the onset of long-term sickness absence and return to work. METHOD: Prospective cohort study on sickness absence with four follow-up years of 53,830 employees working in the private sector in the Netherlands. The time to onset of long-term (>6 weeks) sickness absence and return to work were modelled by parametric hazard rate models. RESULTS: The exponential parametric model with a constant hazard rate most accurately described the time to onset of long-term sickness absence. Gompertz-Makeham models with monotonically declining hazard rates best described return to work. CONCLUSIONS: Parametric models offer more possibilities than commonly used models for time-dependent processes as sickness absence and return to work. However, the advantages of parametric models above Cox models apply mainly for return to work and less for onset of long-term sickness absence

Feasibility and Acute Care Utilization Outcomes of a Post-Acute Transitional Telemonitoring Program for Underserved Chronic Disease Patients

Background: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) are chronic diseases that impart significant health and care costs to the patient and health system. Limited access to health services affects disease severity and functional status. Telemonitoring has shown promise in reducing acute care utilization for chronic disease patients, but the benefit for the underserved has not been determined. We evaluated acute care utilization outcomes following an acute event of a 90-day transitional care program integrating telemonitoring technology and home visits for underserved COPD and HF patients. Materials and Methods: Patients were enrolled into the program between October 2010 and August 2012. Primary outcomes included rates of emergency department (ED) visits and all-cause re-admission at 30, 90, and 180 days postdischarge. Program and functional status at enrollment and discharge and satisfaction with telemonitoring at discharge were measured. Telemonitoring included daily symptomatology recording and was removed at 90 days. A control cohort was identified through electronic health records and propensity-matched via 15 variables to achieve a sample size with balanced baseline characteristics. Results: Program patients showed 50% reduction in 30-day re-admission and 13–19% reduction in 180-day re-admission compared with control patients. There was no significant difference in ED utilization. Patients were satisfied with telemonitoring services, and functional status improved by program end. Conclusions: This feasibility study suggests telemonitoring in the context of a transitional care model following an acute event may reduce all-cause 30-day re-admissions by up to 50% and has the potential to reduce longterm acute care utilization and thus care costs. More rigorous and long-term investigation is warranted

Construction and Random Generation of Hypergraphs with Prescribed Degree and Dimension Sequences

We propose algorithms for construction and random generation of hypergraphs without loops and with prescribed degree and dimension sequences. The objective is to provide a starting point for as well as an alternative to Markov chain Monte Carlo approaches. Our algorithms leverage the transposition of properties and algorithms devised for matrices constituted of zeros and ones with prescribed row- and column-sums to hypergraphs. The construction algorithm extends the applicability of Markov chain Monte Carlo approaches when the initial hypergraph is not provided. The random generation algorithm allows the development of a self-normalised importance sampling estimator for hypergraph properties such as the average clustering coefficient.We prove the correctness of the proposed algorithms. We also prove that the random generation algorithm generates any hypergraph following the prescribed degree and dimension sequences with a non-zero probability. We empirically and comparatively evaluate the effectiveness and efficiency of the random generation algorithm. Experiments show that the random generation algorithm provides stable and accurate estimates of average clustering coefficient, and also demonstrates a better effective sample size in comparison with the Markov chain Monte Carlo approaches.Comment: 21 pages, 3 figure

Prevalence of Disorders Recorded in Dogs Attending Primary-Care Veterinary Practices in England

Purebred dog health is thought to be compromised by an increasing occurence of inherited diseases but inadequate prevalence data on common disorders have hampered efforts to prioritise health reforms. Analysis of primary veterinary practice clinical data has been proposed for reliable estimation of disorder prevalence in dogs. Electronic patient record (EPR) data were collected on 148,741 dogs attending 93 clinics across central and south-eastern England. Analysis in detail of a random sample of EPRs relating to 3,884 dogs from 89 clinics identified the most frequently recorded disorders as otitis externa (prevalence 10.2%, 95% CI: 9.1-11.3), periodontal disease (9.3%, 95% CI: 8.3-10.3) and anal sac impaction (7.1%, 95% CI: 6.1-8.1). Using syndromic classification, the most prevalent body location affected was the head-and-neck (32.8%, 95% CI: 30.7-34.9), the most prevalent organ system affected was the integument (36.3%, 95% CI: 33.9-38.6) and the most prevalent pathophysiologic process diagnosed was inflammation (32.1%, 95% CI: 29.8-34.3). Among the twenty most-frequently recorded disorders, purebred dogs had a significantly higher prevalence compared with crossbreds for three: otitis externa (P = 0.001), obesity (P = 0.006) and skin mass lesion (P = 0.033), and popular breeds differed significantly from each other in their prevalence for five: periodontal disease (P = 0.002), overgrown nails (P = 0.004), degenerative joint disease (P = 0.005), obesity (P = 0.001) and lipoma (P = 0.003). These results fill a crucial data gap in disorder prevalence information and assist with disorder prioritisation. The results suggest that, for maximal impact, breeding reforms should target commonly-diagnosed complex disorders that are amenable to genetic improvement and should place special focus on at-risk breeds. Future studies evaluating disorder severity and duration will augment the usefulness of the disorder prevalence information reported herein