398,814 research outputs found
Integrated helicopter survivability
A high level of survivability is important to protect military personnel and equipment and is
central to UK defence policy. Integrated Survivability is the systems engineering
methodology to achieve optimum survivability at an affordable cost, enabling a mission to
be completed successfully in the face of a hostile environment. “Integrated Helicopter
Survivability” is an emerging discipline that is applying this systems engineering approach
within the helicopter domain. Philosophically the overall survivability objective is ‘zero
attrition’, even though this is unobtainable in practice.
The research question was: “How can helicopter survivability be assessed in an integrated
way so that the best possible level of survivability can be achieved within the constraints and
how will the associated methods support the acquisition process?”
The research found that principles from safety management could be applied to the
survivability problem, in particular reducing survivability risk to as low as reasonably
practicable (ALARP). A survivability assessment process was developed to support this
approach and was linked into the military helicopter life cycle. This process positioned the
survivability assessment methods and associated input data derivation activities.
The system influence diagram method was effective at defining the problem and capturing
the wider survivability interactions, including those with the defence lines of development
(DLOD). Influence diagrams and Quality Function Deployment (QFD) methods were
effective visual tools to elicit stakeholder requirements and improve communication across
organisational and domain boundaries.
The semi-quantitative nature of the QFD method leads to numbers that are not real. These
results are suitable for helping to prioritise requirements early in the helicopter life cycle, but
they cannot provide the quantifiable estimate of risk needed to demonstrate ALARP. The probabilistic approach implemented within the Integrated Survivability Assessment
Model (ISAM) was developed to provide a quantitative estimate of ‘risk’ to support the
approach of reducing survivability risks to ALARP. Limitations in available input data for
the rate of encountering threats leads to a probability of survival that is not a real number that
can be used to assess actual loss rates. However, the method does support an assessment
across platform options, provided that the ‘test environment’ remains consistent throughout
the assessment. The survivability assessment process and ISAM have been applied to an
acquisition programme, where they have been tested to support the survivability decision
making and design process.
The survivability ‘test environment’ is an essential element of the survivability assessment
process and is required by integrated survivability tools such as ISAM. This test
environment, comprising of threatening situations that span the complete spectrum of
helicopter operations requires further development. The ‘test environment’ would be used
throughout the helicopter life cycle from selection of design concepts through to test and
evaluation of delivered solutions. It would be updated as part of the through life capability
management (TLCM) process.
A framework of survivability analysis tools requires development that can provide
probabilistic input data into ISAM and allow derivation of confidence limits. This systems
level framework would be capable of informing more detailed survivability design work
later in the life cycle and could be enabled through a MATLAB® based approach.
Survivability is an emerging system property that influences the whole system capability.
There is a need for holistic capability level analysis tools that quantify survivability along
with other influencing capabilities such as: mobility (payload / range), lethality, situational
awareness, sustainability and other mission capabilities.
It is recommended that an investigation of capability level analysis methods across defence
should be undertaken to ensure a coherent and compliant approach to systems engineering
that adopts best practice from across the domains. Systems dynamics techniques should be
considered for further use by Dstl and the wider MOD, particularly within the survivability
and operational analysis domains. This would improve understanding of the problem space,
promote a more holistic approach and enable a better balance of capability, within which
survivability is one essential element.
There would be value in considering accidental losses within a more comprehensive
‘survivability’ analysis. This approach would enable a better balance to be struck between
safety and survivability risk mitigations and would lead to an improved, more integrated
overall design
The influence of biological rhythms on host–parasite interactions
Biological rhythms, from circadian control of cellular processes to annual cycles in life history, are a main structural element of biology. Biological rhythms are considered adaptive because they enable organisms to partition activities to cope with, and take advantage of, predictable fluctuations in environmental conditions. A flourishing area of immunology is uncovering rhythms in the immune system of animals, including humans. Given the temporal structure of immunity, and rhythms in parasite activity and disease incidence, we propose that the intersection of chronobiology, disease ecology, and evolutionary biology holds the key to understanding host–parasite interactions. Here, we review host–parasite interactions while explicitly considering biological rhythms, and propose that rhythms: influence within-host infection dynamics and transmission between hosts, might account for diel and annual periodicity in host–parasite systems, and can lead to a host–parasite arms race in the temporal domain
Games for a new climate: experiencing the complexity of future risks
This repository item contains a single issue of the Pardee Center Task Force Reports, a publication series that began publishing in 2009 by the Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future.This report is a product of the Pardee Center Task Force on Games for a New Climate, which met at Pardee House at Boston University in March 2012. The 12-member Task Force was convened on behalf of the Pardee Center by Visiting Research Fellow Pablo Suarez in collaboration with the Red Cross/Red Crescent Climate Centre to “explore the potential of participatory, game-based processes for accelerating learning, fostering dialogue, and promoting action through real-world decisions affecting the longer-range future, with an emphasis on humanitarian and development work, particularly involving climate risk management.”
Compiled and edited by Janot Mendler de Suarez, Pablo Suarez and Carina Bachofen, the report includes contributions from all of the Task Force members and provides a detailed exploration of the current and potential ways in which games can be used to help a variety of stakeholders – including subsistence farmers, humanitarian workers, scientists, policymakers, and donors – to both understand and experience the difficulty and risks involved related to decision-making in a complex and uncertain future. The dozen Task Force experts who contributed to the report represent academic institutions, humanitarian organization, other non-governmental organizations, and game design firms with backgrounds ranging from climate modeling and anthropology to community-level disaster management and national and global policymaking as well as game design.Red Cross/Red Crescent Climate Centr
Expert Elicitation for Reliable System Design
This paper reviews the role of expert judgement to support reliability
assessments within the systems engineering design process. Generic design
processes are described to give the context and a discussion is given about the
nature of the reliability assessments required in the different systems
engineering phases. It is argued that, as far as meeting reliability
requirements is concerned, the whole design process is more akin to a
statistical control process than to a straightforward statistical problem of
assessing an unknown distribution. This leads to features of the expert
judgement problem in the design context which are substantially different from
those seen, for example, in risk assessment. In particular, the role of experts
in problem structuring and in developing failure mitigation options is much
more prominent, and there is a need to take into account the reliability
potential for future mitigation measures downstream in the system life cycle.
An overview is given of the stakeholders typically involved in large scale
systems engineering design projects, and this is used to argue the need for
methods that expose potential judgemental biases in order to generate analyses
that can be said to provide rational consensus about uncertainties. Finally, a
number of key points are developed with the aim of moving toward a framework
that provides a holistic method for tracking reliability assessment through the
design process.Comment: This paper commented in: [arXiv:0708.0285], [arXiv:0708.0287],
[arXiv:0708.0288]. Rejoinder in [arXiv:0708.0293]. Published at
http://dx.doi.org/10.1214/088342306000000510 in the Statistical Science
(http://www.imstat.org/sts/) by the Institute of Mathematical Statistics
(http://www.imstat.org
Effect of flow pattern at pipe bends on corrosion behaviour of low carbon steek and its challenges
Recent design work regarding seawater flow lines has emphasized the need to identify, develop, and verify critical relationships between corrosion prediction and flow regime mechanisms at pipe bend. In practice this often reduces to an pragmatic interpretation of the effects of corrosion mechanisms at pipe bends. Most importantly the identification of positions or sites, within the internal surface contact areas where the maximum corrosion stimulus may be expected to occur, thereby allowing better understanding, mitigation, monitoring and corrosion control over the life cycle. Some case histories have been reviewed in this context, and the interaction between corrosion mechanisms and flow patterns closely determined, and in some cases correlated. Since the actual relationships are complex, it was determined that a risk based decision making process using selected ‘what’ if corrosion analyses linked to ‘what if’ flow assurance analyses was the best way forward. Using this in methodology, and pertinent field data exchange, it is postulated that significant improvements in corrosion prediction can be made. This paper outlines the approach used and shows how related corrosion modelling software data such as that available from corrosion models Norsok M5006, and Cassandra to parallel computational flow modelling in a targeted manner can generate very noteworthy results, and considerably more viable trends for corrosion control guidance. It is postulated that the normally associated lack of agreement between corrosion modelling and field experience, is more likely due to inadequate consideration of corrosion stimulating flow regime data, rather than limitations of the corrosion modelling. Applications of flow visualization studies as well as computations with the k-ε model of turbulence have identified flow features and regions where metal loss is a maximu
Upgrading investment regulations in second pillar pension systems : a proposal for Colombia
The passivity of the demand for pension products is one of the striking features of mandatory pension systems. Consequently, the provision of multiple investment alternatives to households (multifund schemes) does not ensure that contributions are invested efficiently. In addition, despite the theoretical findings that short term return maximization is not conductive to long-term return maximization, the regulatory framework of pension fund management companies puts excessive emphasis on short-term maximization. Therefore, it is not obvious that typical regulatory framework of pension funds is conductive to optimal pensions. By establishing a set of default options on investment portfolios, this paper proposes a mechanism to align the incentives of the pension fund management companies with the long-term objectives of the contributors. The paper provides a methodology, which is subsequently applied to Colombia.Debt Markets,Emerging Markets,Financial Literacy,Mutual Funds,Investment and Investment Climate
Adaptation of domestic state governance to international governance models
The purpose of the article is to provide the evolving international trends of modern management models and authorial vision of model of state governance system in Ukraine, its subsystems, in particular, the system of provision of administrative services that is appropriate for the contemporary times. Methodology. On the basis of scientific and theoretical approaches to the definitions of terms “state governance” and “public governance”, there was an explanation of considerable difference between them and, taking into consideration, the mentality of Ukrainian society and peculiar weak side in self-organization, the authors offered to form authorial model of governance on the basis of historically traditional for Ukraine model of state governance and to add some elements of management concepts that proved their significance, efficiency and priority in practice. Results. The authors emphasized the following two prevailing modern management models in the international practice: “new state management” and “good governance”. The first concept offered for consideration served as a basis for the semantic content of state activity that reflects more the state of administrative reformation. Practical meaning. A practical introduction of management to the domestic model of governance creates the range of contradictions that do not allow implementing herein concept. Pursuant to authors, the second one allows in considerable measure to reform state governance, considering historically developed peculiarities of this model. Moreover, the involvement of concept herein into introduction of informational and communicational technologies in the process of governance eliminates the necessity of power decentralization, it allows to form real net structure and, at the same, to keep vertical power structure, to involve citizens for formation and taking of management decisions, to form electronic communicational channel of feedback, to provide citizens with electronic administrative services. All indicated advantages of the concept certify about the necessity to reform state governance exactly in this field. Meaning/ Distinction. This article raises a question about the significance of formation and sequence of state policy in Ukraine aimed at creating an information-oriented society, space, as well as informational and technological infrastructure
Student evaluation towards educator performance for Technical College in Malaysia
Student feedback is one of the important components in the learning and teaching process evaluation at various stages of higher level education in Malaysia. Kolej Kemahiran Tinggi MARA Sri Gading (KKTMSG) with eight departments is a location of study that have intakes twice a year, January-June (JJ) and July-December (JD). A continuous assessment by student has been executed over years and compulsory to fill in during the final examination week around May and November. Four objectives of this study are to determine if there is any correlation exist between Educator Mark with Total Marks of Personality and Teaching and Learning, to investigate if there is any correlation exist between Personality and its criteria, to explore if there is any correlation exist between Teaching and Learning and its each criteria and finally to determine if any association exist between Gender and Educator Mark with hypothesis null that both variables are independent. Main instrument used is a questionnaire with quantitative research design sur-vey technique consists of basic Demography, Personality and Teaching and Learning sections. The survey question is in a Likert scale start from 1 to 5 that represent Never, Almost Never, Sometimes, Almost Every Time and Every Time respectively. The dependent variable is an Educator Mark meanwhile the independent variables consists of 24 variables known as Semester, Year, Educator, Gender, Department, Student, 20 variables of criteria selection from Personality with 8 questions and from Teaching and Learning with 12 questions in a Likert scale. Descriptive analysis, correlation analysis and chi-square test have been adopted to this study. Result shows that 55.4% and 44.6% of the sample data are male and female respectively, which sounds reasonable represent the population of educator in KKTMSG and the highest respondent for both genders represent from PA Department. First objective presents a strong relationship with correlation value at 0.976 for Teaching and Learning compared to Personality and second objective shows all criteria have strong relationship with criteria Fairness, E presents highest correlation value at 0.976 compared to others. In the meantime, third objective 3 display similar result that criteria Committed During Teaching and Learning Process, T represents highest correlation value at 0.984 compared to others. All these results were based on significant p-value of less than 0.05. Finally, a Chi-Square Test conclude that Gender and Educator Mark are independent, and this shows that students are freely to evaluate educator in KKTMSG without consider or concern either the educator is male or female
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