Development of the Trident 1 aerodynamic saike mechanism

The Aerospike drag reduction mechanism was designed and developed for use on the Trident I submarine launched ballistic missile. This mechanism encounters a unique combination of environments necessitating unique design solutions to ensure satisfactory operation over its design life. The development of the Aerospike is reviewed emphasizing the unique and interesting problems encountered and their solutions

Opportunities for Launch Site Integrated System Health Engineering and Management

The launch site processing flow involves operations such as functional verification, preflight servicing and launch. These operations often include hazards that must be controlled to protect human life and critical space hardware assets. Existing command and control capabilities are limited to simple limit checking durig automated monitoring. Contingency actions are highly dependent on human recognition, decision making, and execution. Many opportunities for Integrated System Health Engineering and Management (ISHEM) exist throughout the processing flow. This paper will present the current human-centered approach to health management as performed today for the shuttle and space station programs. In addition, it will address some of the more critical ISHEM needs, and provide recommendations for future implementation of ISHEM at the launch site

Beyond balancing? Intrastate conflict and US grand strategy

ArticleThis is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge) via the DOI in this record.Grand strategic theorists share an historical emphasis on interstate conflict. However, of some two hundred and seventy-three US military deployments since 1900, only seven were interstate conflicts. The rest were intrastate, domestic level engagements. We argue that these intrastate conflicts limit the utility of regional balances of power in mitigating forms of conflict that the US may consider inimical to its national security interests. When considering potential changes to US force posture and grand strategy, American coercive statecraft should be theorised along a broader strategic continuum encompassing the full range of conflict

Security Leverage, Structural power and US Strategy in East Asia

This is the author accepted manuscript. The final version is available from OUP via the DOI in this record.What is the utility of US military power when seeking to generate international economic arrangements conducive to its national interests? Developing the concepts of positive and negative structural power we argue that regional American primacy in East Asia has allowed it to leverage its military power into generating political-economic institutional outcomes that have reinforced its broader leadership role. The US may well continue its deep engagement or follow a path of retrenchment under President Trump. Both grand strategic options will impact on its capacity to leverage its positive and negative structural power and have implications for US hegemony and the region’s political economy

How to Extend the Capabilities of Space Systems for Long Duration Space Exploration Systems

For sustainable Exploration Missions the need exists to assemble systems-of-systems in space, on the Moon or on other planetary surfaces. To fulfill this need new and innovative system architecture is needed that can be satisfied with the present lift capability of existing rocket technology without the added cost of developing a new heavy lift vehicle. To enable ultra-long life missions with minimum redundancy and lighter mass the need exists to develop system soft,i,are and hardware reconfigurability, which enables increasing functionality and multiple use of launched assets while at the same time overcoming any components failures. Also the need exists to develop the ability to dynamically demate and reassemble individual system elements during a mission in order to work around failed hardware or changed mission requirements. Therefore to meet the goals of Space Exploration Missions in hiteroperability and Reconfigurability, many challenges must be addressed to transform the traditional static avionics architecture into architecture with dynamic capabilities. The objective of this paper is to introduce concepts associated with reconfigurable computer systems; review the various needs and challenges associated with reconfigurable avionics space systems; provide an operational example that illustrates the needs applicable to either the Crew Exploration Vehicle or a collection of "Habot like" mobile surface elements; summarize the approaches that address key challenges to acceptance of a Flexible, Intelligent, Modular and Affordable reconfigurable avionics space system

End-of-life care in a psychiatric hospital.

Since the Liverpool Care Pathway has been withdrawn in the UK, clinicians supporting the palliative needs of patients have faced further challenges, particularly for patients with dementia who are unable to go to a hospice owing to challenging behaviours. It is becoming more important for different services to provide long-term palliative care for patients with dementia. Mental health trusts should construct end-of-life care policies and train staff members accordingly. Through collaborative working, dying patients may be kept where they are best suited. We present the case study of a patient who received end-of-life care at a psychiatric hospital in the UK. We aim to demonstrate how effective end-of-life care might be provided in a psychiatric hospital, in accordance with recent new palliative care guidelines, and highlight potential barriers

An O(n^3)-Time Algorithm for Tree Edit Distance

The {\em edit distance} between two ordered trees with vertex labels is the minimum cost of transforming one tree into the other by a sequence of elementary operations consisting of deleting and relabeling existing nodes, as well as inserting new nodes. In this paper, we present a worst-case $O(n^3)$-time algorithm for this problem, improving the previous best $O(n^3\log n)$-time algorithm~\cite{Klein}. Our result requires a novel adaptive strategy for deciding how a dynamic program divides into subproblems (which is interesting in its own right), together with a deeper understanding of the previous algorithms for the problem. We also prove the optimality of our algorithm among the family of \emph{decomposition strategy} algorithms--which also includes the previous fastest algorithms--by tightening the known lower bound of $\Omega(n^2\log^2 n)$~\cite{Touzet} to $\Omega(n^3)$, matching our algorithm's running time. Furthermore, we obtain matching upper and lower bounds of $\Theta(n m^2 (1 + \log \frac{n}{m}))$ when the two trees have different sizes $m$ and~$n$, where $m < n$.Comment: 10 pages, 5 figures, 5 .tex files where TED.tex is the main on

Left hepatic trisegmentectomy

Left hepatic trisegmentectomy was successfully performed upon four patients in whom the true left lobe of the liver and all, or part, of the anterior segment of the right lobe of the liver were removed in continuity. Three of the patients had carcinoma of the liver, and the fourth patient had a hemangioma and arteriovenous malformation. This procedure, which has not been described before, should allow subtotal hepatic resection to be performed upon some patients who have lesions that have been classified as inoperable, in the past

Exact Asymptotic Results for a Model of Sequence Alignment

Finding analytically the statistics of the longest common subsequence (LCS) of a pair of random sequences drawn from c alphabets is a challenging problem in computational evolutionary biology. We present exact asymptotic results for the distribution of the LCS in a simpler, yet nontrivial, variant of the original model called the Bernoulli matching (BM) model which reduces to the original model in the large c limit. We show that in the BM model, for all c, the distribution of the asymptotic length of the LCS, suitably scaled, is identical to the Tracy-Widom distribution of the largest eigenvalue of a random matrix whose entries are drawn from a Gaussian unitary ensemble. In particular, in the large c limit, this provides an exact expression for the asymptotic length distribution in the original LCS problem.Comment: 4 pages Revtex, 2 .eps figures include