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Cyber-Physical Systems (CPS) often rely on network boundary defence as a primary means of access control; therefore, the compromise of one device threatens the security of all devices within the boundary. Resource and real-time constraints, tight hardware/software coupling, and decades-long service lifetimes complicate efforts for more robust, host-based access control mechanisms. Distributed capability systems provide opportunities for restoring access control to resource-owning devices; however, such a protection model requires a capability-based architecture for CPS devices as well as task compartmentalisation to be effective. This paper demonstrates hardware enforcement of network bearer tokens using an efficient translation between CHERI (Capability Hardware Enhanced RISC Instructions) architectural capabilities and Macaroon network tokens. While this method appears to generalise to any network-based access control problem, we specifically consider CPS, as our method is well-suited for controlling resources in the physical domain. We demonstrate the method in a distributed robotics application and in a hierarchical industrial control application, and discuss our plans to evaluate and extend the method.

This paper investigates the potential of polynomial chaos methods, when used in conjunction with computational fluid dynamics, to quantify the effects of uncertainty in the computational aerodynamic design process. The technique is shown to be an efficient and accurate means of simulating the inherent uncertainty and variability in manufacturing and flow conditions and thus can provide the basis for computationally feasible robust optimization with computational fluid dynamics. This paper presents polynomial chaos theory and the nonintrusive spectral projection implementation, using this to demonstrate polynomial chaos as a basis for robust optimization, focusing on the problem of maximizing the lift-to-drag ratio of a two-dimensional airfoil while minimizing its sensitivity to uncertainty in the leading-edge thickness. The results demonstrate that the robustly optimized designs are significantly less sensitive to input variation, compared with nonrobustly optimized airfoils. The results also indicate that the inherent geometric uncertainty could degrade the on-design as well as the offdesign performance of the nonrobust airfoil. This leads to the further conclusion that the global optimum for some design problems is unreachable without accounting for uncertainty.

The main requirements for a fast igniter laser beam are reviewed and shown to favour short wavelength and ultrahigh brightness. These requirements are met by the new KrF laser system at Rutherford Appleton Laboratory called TITANIA. TITANIA uses two schemes to enhance the laser beam brightness. The first is chirped pulse amplification which is used to enhance brightness by compressing the pulse into the femtosecond region. In this mode TITANIA produces in the region of 250 mJ on target in 700 fs. The second mode of operation uses a Raman technique for beam combining and beam clean-up which is designed to give a single beam of 80 joules on target in a pulselength of 60 ps. In this scheme the KrF wavelength is Raman shifted to 268 nm. The Raman amplifiers will use gaseous rather than solid windows and experiments which demonstrate their feasibility will be described. A concept for a reactor scale fast igniter beam using the Raman technique will be discussed.

Diamond's extremely wide transparency, combined with its other exceptional properties including hardness, strength and thermal conductivity make it a desirable material for optical windows. Polycrystalline diamond grown by chemical vapour deposition (CVD) has become the preferred window material for high power CO2 laser systems since its development in the 1990s. The range and availability of diamond materials is expanding, and in recent years has been extended to include CVD single crystal diamond. This paper reviews the quality of these materials, looking at optical scatter and absorption around 1 and 10 microns, along with their thermal and mechanical properties. We also discuss selection of appropriate grades and how they may best be integrated into demanding optical applications.

In this work, we experimentally demonstrate a novel and simple approach that uses off-the-shelf optical elements to enhance the collection efficiency from a single emitter. The key component is a solid immersion lens made of diamond, the host material for single color centers. We improve the excitation and detection of single emitters by one order of magnitude, as predicted by theory.

The multiple mini-interview (MMI) overcomes the limitations of the traditional panel interview by multiple sampling to provide improved objectivity and reliability. Reliability of the MMI is affected by number of stations; however, there are few data reporting the influence of interview duration on MMI outcome and reliability. We aimed to determine whether MMI stations can be shortened without affecting applicant rankings or compromising test reliability.A total of 175 applicants were interviewed and assessed at 10 8-minute stations. Applicants were scored once after 8 minutes at five control stations and twice after 5 minutes and 8 minutes at five experimental stations. Scores at 5 and 8 minutes were compared using t-tests and correlation coefficients. Rankings of applicants based on 5- and 8-minute scores were compared using Spearman's rank order coefficient. The reliability of the MMI was examined for 5- and 8-minute scores using generalisability theory.Mean scores at 5 minutes were lower than mean scores at 8 minutes. Cumulative scores at 5 minutes were also lower. There were highly significant correlations between 5- and 8-minute scores at all experimental stations (0.82-0.91; P0.01) and between the cumulative scores at 5 and 8 minutes (0.92; P0.01). There was a strong correlation between applicant rankings based on cumulative 5- and 8-minute scores (Spearman's rank order coefficient 0.92). Reliability was not affected.Reducing the duration of MMI stations from 8 to 5 minutes conserves resources with minimal effect on applicant ranking and test reliability.

In a recent flight experiment to study hypersoniccrossflow transition, boundary layer characteristics weredocumented. A smooth steel glove was mounted on thefirst stage delta wing of Orbital Sciences Corporation'sPegasus ® launch vehicle and was flown at speeds of upAerospace Engineer, Member MAA?Instrumentation Engineer+Instrumentation Engineer§Insmnnentafion Engineer¶Aerospace EngineerFlight Assurance Analyst"_'_Aelos,, • pace Engineel • HH ++Instrumentation Engineer§§Instrumentation Engineer¶¶Engineel_rtg Technician***Software SpecialistCopyright ® 2000 by the American Institute of Aeronautics andAstronautics, Inc. No copyright is asserted in the United States _mderTitle 17, U.S. Code. The U.S. Government has a royalty flee licenseto exercise all fights under the copyright claimed herein for Governmental purposes. All other fights are reserved by the copyright owner.to Mach 8 and altitudes of up to 250,000 ft. The wing-glove experiment was flown as a secondary payload offthe coast of Florida in October 1998. This paperdescribes the measurement system developed. Samplesof the results obtained for different parts of thetrajectory are included to show the characteristics andquality of the data. Thermocouples and pressure sensors(including Preston tubes, Stanton tubes, and a'probeless' pressure rake showing boundary layerprofiles) measured the time-averaged flow. Surface hot-films and high-frequency pressure transducers measuredflow dynamics. Because the vehicle was notrecoverable, it was necessary to design a system for real-time onboard processing and transmission. Onboardprocessing included spectral averaging. The quality andconsistency of data obtained was good and met theexperiment requirements.