Systems Engineering and Assessment (United Kingdom)

<div class="section abstract"><div class="htmlview paragraph">Testing vision-based advanced driver assistance systems (ADAS) in a Camera-in-the-Loop (CiL) bench setup, where external visual inputs are used to stimulate the system, provides an opportunity to experiment with a wide variety of test scenarios, different types of vehicle actors, vulnerable road users, and weather conditions that may be difficult to replicate in the real world. In addition, once the CiL bench is setup and operating, experiments can be performed in less time when compared to track testing alternatives. In order to better quantify normal operating zones, track testing results were used to identify behavior corridors via a statistical methodology. After determining normal operational variability via track testing of baseline stationary surrogate vehicle and pedestrian scenarios, these operating zones were applied to screen-based testing in a CiL test setup to determine particularly challenging scenarios which might benefit from replication in a track testing environment. For this work, a Mobileye 6 aftermarket ADAS camera sensor system was tested in first a track environment and then a CiL simulation environment using Siemens Prescan. A variety of actor and environmental variables were tested, including different pedestrian and vehicle surrogates and varying levels of precipitation and atmospheric effects. From these tests, interesting scenarios in which there was a delayed or non-reaction from the camera were identified. These scenarios, in which the Mobileye system had variable performance, could be further tested in a track environment to better understand the response.</div></div>

Population‐level estimates of offspring sex ratios in birds typically approximate parity whereas biased ratios within nests are not uncommon. In sexually dimorphic raptors, the costs and relative fitness benefits of rearing male and female progeny vary with changing environmental circumstances. This may lead to substantial deviations from balanced investment in offspring of a particular sex by individual parents. Based on a 13‐year dataset for breeding MerlinsFalco columbariusin Saskatoon, Canada, we used a model selection approach to assess the influence of parents, nest‐mates and nesting area on brood sex ratio during the nestling phase. The best model for predicting brood sex ratio included age of the breeding male and brood size for each nest (n = 127); nests with older male breeders and smaller brood sizes had more female young. The population‐level annualized average proportion of male offspring was 0.472 ± 0.017 (mean ± standard error), but tended towards greater production of female young during an initial period of population growth (8 years, 10–21 pairs; proportion male 0.435 ± 0.031) versus a period when the population fluctuated around a presumed carrying capacity (11 years, 24–33 pairs; proportion male 0.500 ± 0.017). Energetics appears to be a finely tuned mechanism driving sex ratio allocation in Merlins at both brood and population levels. Provisioning food for young in the nest represents the male's ability to successfully capture prey, reflecting his age and/or experience, as well as the availability of prey to the male. Confounding this mechanism to determine sex ratio allocation are the pressures created by population dynamics that dictate competition for resources both within the nest (brood size) and external to the nest (population density).

<div class="section abstract"><div class="htmlview paragraph">Intersections have a high risk of vehicle-to-vehicle conflicts because of the overlapping traffic flow from multiple roads. To understand the factors contributing to the crashes, this study examines the common characteristics in intersection-related crash and near- crash events, such as the existence of traffic control devices, the driver at fault, and occurrence of visual obstructions. The descriptive data of the crash and near-crash events recorded in the Second Strategic Highway Research Program Naturalistic Driving Study (SHRP 2 NDS) database is used in categorization and statistical analysis in this study. First, the events are divided into seven categories based on trajectories of the conflicting vehicles. The categorization provides the basis for in-depth analysis of crash-contributing factors in specific confliction patterns. Subsequently, descriptive statistics are used to portray each of the categories. The severity of the categories is determined based of the frequency of occurrences of the crashes and near-crashes. Factors contributing to each crash category are then examined based on their frequency of occurrence with the categories. This study reveals the severity of different intersection-related crash patterns, as well as the effects of some crash-contributing factors. The information presented in this paper has the potential to guide investigators interested in developing simulation and test track scenarios to evaluate vehicles equipped with automated driving systems (ADS).</div></div>

Monopiles supporting offshore wind turbines can experience permanent non-recoverable rotations (or displacements) during their lifetime due to the cyclic nature of hydrodynamic and aerodynamic loading exerted on them. Recent studies in the literature have demonstrated that conventional cyclic p–y curves recommended in different codes of practice (API-RP-2GEO and DNVGL-RP-C212) may not capture the effects of long-term cyclic loads as they are independent of the loading profile and the number of applied cycles. Several published methodologies based on laboratory scaled model tests (on sands) exist to determine the effect of cyclic lateral loads on the long-term behaviour of piles. The tests vary in terms of the pile behaviour (rigid or flexible pile), number of applied loading cycles, and the load profile (one-way or two-way loading). The best-fit curves provided by these tests offer practical and cost-efficient methods to quantify the accumulated rotations when compared to Finite Element Method. It is therefore desirable that such methods are further developed to take into account different soil types and the complex nature of the loading. The objective of this paper is to compare the performance of the available formulations under the actions of a typical 35-h (hour) storm as per the Bundesamt für Seeschifffahrt und Hydrographie (BSH) recommendations. Using classical rain flow counting, the loading time-history is discretized into load packets where each packet has a loading profile and number of cycles, which then enables the computation of an equivalent number of cycles of the largest load packet. The results show that the loading profile plays a detrimental role in the result of the accumulated rotation. Furthermore, flexibility of the pile also has an important effect on the response of the pile where predictions obtained from formulations based on flexible piles resulted in a much lower accumulated rotation than tests based on rigid piles. Finally, the findings of this paper are expected to contribute in the design and interpretation of future experimental frameworks for Offshore Wind Turbine (OWT) monopiles in sands, which will include a more realistic loading profile, number of cycles, and relative soil to pile stiffness.

<div class="section abstract"><div class="htmlview paragraph">A machine has been developed to measure the center-of-gravity (CG) location of a seat. This machine uses a system of pivots, a yaw bearing and two sensors to get the X, Y and Z CG of the seat. Test object mass is measured separately on a scale. A stable pendulum arrangement is used to get the CG location. Governing equations for the machine are shown in the paper and a typical test procedure is discussed. An error analysis is discussed and shows the requisite accuracy of platform angle, geometric dimensions, seat weight and applied weight in order to achieve the desired 3 mm accuracy target. A full system statistical analysis demonstrates that all X and Y CG locations, when compared with theoretical values, are off by less than 1 mm and well within the 3 mm accuracy target. For Z CG, the errors were shown to be 3.3 mm or lower with 95 percent confidence.</div></div>

Ecological and social resilience have emerged globally as important considerations in impact assessment. Addressing resilience requires an understanding of the interconnectedness of environmental, social, and economic issues affecting the sustainability of ecosystems and human communities. However, indicators and tools for measuring resilience remain in early stages of understanding and development. Regulatory agencies and sponsors of large resource development and environmental rehabilitation projects have difficulties interpreting and verifying the potential for environmental recovery and resilience in the regulatory context of impact assessment. Resilience poses several challenges to traditional approaches to environmental assessment. For example, scientists ordinarily use marginal analysis in impact assessment, which lends itself to linear extrapolation to fill both knowledge and data gaps. At the ecosystem level, we know this is a poor approximation method. In particular, resilience has called attention to tipping points (or thresholds), at which ecosystem response becomes (abruptly) nonlinear. The challenge in impact assessment is understanding how complex ecological systems respond to stressors near these tipping points when the underlying protective factors or adaptive capacity of the system are undermined. It is generally understood there is no single cause for a particular response, although current legal frameworks emphasize simplistic understandings of cause–effect and liability. Resilience concepts are better suited for analytic perspectives that recognize the nonlinearity, feedback loops, and stochasticity that characterize ecosystems. Thus, resilience raises a new challenge for environmental managers and decision makers working in environmental contexts, namely: "What are the impacts of a management action on the sensing, anticipating, adapting, and learning processes of the system?" (Park et al. 2013). "Embedding resiliency concepts and assessment tools into the impact assessment process has the potential to significantly influence project decision making." If challenges can be overcome, embedding resiliency concepts and assessment tools into the impact assessment process has the potential to significantly influence project decision making, particularly for so-called megascale infrastructure and resource development projects in which the scale of the short- and long-term environmental changes can be substantial. The central question concerns the ability of affected ecosystems to recover most if not all structural and functional characteristics that were evident before change occurred. Additionally, can modified systems be set on a trajectory of new conditions that reflect and satisfy the values and desires of communities affected by changes to the ecosystem? Central to such an evaluation is the understanding of what aspects or functions of societies and ecosystems are the most vulnerable, valued, or essential to change and recovery. Ecosystems are not infinitely resilient. Resilience thinking must incorporate respect for and humility regarding uncertainty, particularly affording careful consideration of tipping points beyond which changes lead to different structural and functional capacities that cannot adequately deliver the desired ecosystem services. Some governmental and industry organizations are calling for resilience-based strategies to help communities cope with unexpected and sudden environmental changes such as those associated with natural or human-caused disaster. The International Risk Governance Council (IRGC) describes the urgent need for resilience strategies to address the potential for catastrophic consequences in a resource guide on resilience (Florin and Linkov 2016). According to IGRC, the occurrence of disasters and crises, following both extreme natural events and anthropogenic accidents, demonstrates the limitations of traditional risk assessment and management. Resilience management has been discussed as both a supplement and an alternative to conventional risk management. Resilience strategies could target planning and preparedness efforts aimed at identifying risks and vulnerabilities, and could support development planning efforts to preempt avoidable consequences or mitigate worst-case upset scenarios. Forensic analysis of ecological and social responses to natural and anthropogenic disasters can provide insights on tolerances and adaptability to environmental changes. Similarly, posthoc monitoring of predictions in risk assessments can provide information useful to forecasting future environmental conditions and opportunities to improve predictions of environmental recovery. Several significant technical challenges must be overcome (Seager et al. 2017). One of the most obvious ones is resolving a universally acceptable definition, or set of definitions, of "resilience" in the context of environmental impact assessment. Should assessors adopt a definition inspired by the engineering discipline wherein resilience is the measure of an object's ability to recover its original form when placed under pressure? Or, should assessors adopt a broader definition reflecting at a larger scale the ability of an ecosystem to absorb and recover from the impact of disruptive events without fundamental changes in function or structure? Interestingly, the word "resilience" was voted the "development buzzword" of 2012 (Winderl 2014), despite leaving many confused about what the word actually means (Mayunga 2007; Davoudi 2012; Mitchell 2013). At a minimum, given the range of definitions that can and have been applied, all applications of resilience concepts should be couched in terms of explicitly laid-out definitions and assumptions (e.g., Woods 2015). Another equally daunting challenge associated with creating an objective framework that incorporates resilience into impact assessment involves the definition of relevant sets of quantitative or qualitative indicators and the associated tools to describe tolerance and adaptation, predict the likelihood for collapse, and anticipate thresholds for new conditions. This challenge has become a key priority for decision makers worldwide. It has prompted the development of several frameworks and toolkits such as the resilience assessment toolkit developed by the United Nations University Institute for the Advanced Study of Sustainability, Bioversity International, the Institute for Global Environmental Strategies, and the United Nations Development Programme (UNU-IAS, BI, IGES, UNDP 2014). Similarily, the Overseas Development Institute has identified a set of 17 resilience indicators for ecosystems (Schipper and Langston 2015). In Principles for Building Resilience: Sustaining Ecosystem Services in Social-Ecological Systems, Biggs et al. (2015) identify 7 principles, 3 recognizably from the ecological side and 4 from the social side, that are most critical for resilience: maintain diversity and redundancy, manage connectivity, manage slow variables and feedbacks, foster an understanding of social–ecological systems as complex adaptive systems, encourage learning and experimentation, broaden participation, and promote polycentric governance systems. No doubt there are other important challenges. Practitioners need to consider the integration of resilience concepts with ancillary impact assessment methods such as ecosystem service assessment, sustainability analysis, and habitat-based assessment. Scientists and regulatory authorities also need to recognize and distinguish differences in community values, social equity, and vulnerability in the context of resilience in different landscapes, and to consider the varying degrees of habitation, alteration, and management. After all, resilience can have different meanings and constructs in different environmental and social contexts. The science community involved with the Society of Environmental Toxicology and Chemistry (SETAC) journal Integrated Environmental Assessment and Management (IEAM) supports research to resolve these challenges and encourages bridge building to link the science of resilience and the practice of environmental impact assessment. Richard J Wenning SETAC Editor-in-Chief, Integrated Environmental Assessment and Management Sabine E Apitz SEA Environmental Decisions, Little Hadham, United Kingdom Senior Editor, Integrated Environmental Assessment and Management Larry Kapustka LK Consultancy, Calgary, Alberta, Canada Thomas Seager Arizona State University, Tempe, Arizona, USA

The HMS Dryad scenarios were a highly complex interaction of crew and communication channels. This chapter describes a study conducted to analyse aspects of command and control in the Naval domain. The operation sequence diagrams give a graphical representation of each of the scenarios with the circles representing transmissions in communication. The anti-air warfare officer was the main agent observed in the air threat scenario and the principal warfare officer was the main agent observed for the subsurface and surface threat scenarios. The knowledge objects identified represent the ideal collection of knowledge objects for the scenarios that were used in the Critical Decision Method analyses. To simplify the analyses, a single network has been presented, comprising both types of knowledge object, but only the knowledge objects relevant to each scenario are highlighted. The knowledge objects pertinent to each phase have been highlighted in each of the propositional networks.