Vibrational processing of a dynamic structural flight system: A multichannel spectral estimation approach.

Dynamic testing of large flight vehicles (rockets) is not only complex, but also can be very costly. These flights are infrequent and can lead to disastrous effects if something were to fail during the flight. The development of sensors coupled to internal components offers a great challenge in reducing their size, yet still maintaining their precision. Sounding rockets provide both a viable and convenient alternative to the more costly vehicular flights. Some of the major objectives are to test various types of sensors for monitoring components of high interest as well as investigating real-time processing techniques. Signal processing presents an extreme challenge in this noisy multichannel environment. The estimation and tracking of modal frequencies from vibrating structures is an important set of features that can provide information about the components under test; therefore, high resolution multichannel spectral processing is required. The application of both single channel and multichannel techniques capable of producing reliable modal frequency estimates of a vibrating structure from uncertain accelerometer measurements is discussed.

Multichannel processing of vibrational measurements: A constrained subspace application.

Monitoring mechanical systems operating in uncertain environments contaminated with both environmental disturbances and noise lead directly to low signal-to-noise-ratios, creating an extremely challenging processing problem, especially in real-time. In order to estimate the performance of a particular system from uncertain vibrational data, it is necessary to identify its unique resonant (modal) frequency signature. The monitoring of structural modes to determine the condition of a device under investigation is essential, especially if it is a critical entity of an operational system. The development of a model-based scheme capable of the on-line tracking of the inherent structural modal frequencies by applying both constrained subspace identification techniques to extract the modal frequencies and state estimation methods to track the evolution is discussed. An application of this approach to a cylindrical structural device (pipe-in-air) is analyzed based on theoretical simulations along with controlled validation experiments, including injected anomalies illustrate the approach and performance. Statistics are gathered to bound potential processors for real-time performance employing these constrained techniques.

Immunizing children to protect against the increasing risk of hepatitis A in adolescents and young adults in South Korea.

We evaluated the CR326F strain (VAQTA) derived hepatitis A vaccine in Korean children and adolescents >2 years of age to consider a future immunization program. In our study, the pediatric two-dose regimen of VAQTA was found to be generally well tolerated and resulted in 100% (95% CI 94.8, 100.0) seroconversion after 2 doses. Immunizing children with the HAV vaccine routinely should be considered in South Korea, particularly in areas where recent outbreaks have occurred.

A randomized study of a flexible booster dosing regimen of VAQTA in adults: safety, tolerability, and immunogenicity.

BACKGROUND: VAQTA (hepatitis A vaccine inactivated, Merck & Co., Inc., West Point, PA) is licensed for use in healthy adults in a two-dose schedule at 0 and 6 months. OBJECTIVE: to determine whether the responses to a booster dose of VAQTA administered to adults 12 or 18 months after the first dose were similar to the response when the booster dose was administered 6 months after the first dose. METHODS: healthy adults were randomized to receive 50-U of VAQTA at 6 (Group I), 12 (Group II), or 18 months (Group III) following receipt of Dose 1 on Day 0. Blood samples were collected immediately prior to Doses 1 and 2 and then, 4 weeks following Dose 2. Seropositivity rates (SPRs), geometric mean titers (GMTs) in milli-international units per milliliter (mIU/ml) and booster response rates (BRRs) were compared among treatment groups. Safety data were collected on Vaccination Report Cards. RESULTS: no serious adverse experiences were reported, and the vaccine was well-tolerated by subjects in the three treatment groups. One month following the booster dose, SPRs and GMTs for Groups I, II, and III, respectively, were, 100% (102/102) and 6726.4 mIU/ml; 97.9% (93/95) and 4863.8 mIU/ml; 100% (86/86) and 6068.3 mIU/ml. The BRRs were 88.2% (Group I), 90.2% (Group II) and 94.2% (Group III). CONCLUSION: responses to the booster dose were comparable regardless of the timing (i.e. 6, 12, or 18 months following Dose 1). Flexibility in the timing of the booster dose of VAQTA in adults would allow the vaccination schedule to be the same for adults, adolescents, and children and may increase the likelihood that adults receive the booster dose.

Royal Navy/Royal Marines Surgical Team exercise Clockwork North, Norway.

The integration of RNST 1 and 3 together with our integration as a whole with Med Squadron was successfully and effectively implemented and clearly indicated that should we be required to work together as a collective in the future, either in a training capacity or on an operational deployment, we are prepared. The opportunity to carry out AST was highly beneficial and although taxing at times for many, provided a package suitable for all levels of experience. Once again, living in such field conditions was often interesting, sometimes daunting and also eye-opening. The change to the MEDEX phase of the deployment was a disappointment to most but another exercise is planned in Wales. On a positive note, it was very beneficial to actually be involved in erecting the DRASH as previously we had only ever seen it in its formed state. In conclusion, the poignant message from this exercise took three main forms: first, the integration of the two teams was smooth and we worked well together. Secondly, we all learnt something from the high quality arctic training we were given and all successfully passed this, and finally, some new aspects to the DRASH system. All in all this deployment was of a high standard and has shown that the interaction between Med Squadron, Cdo Logistics Regt RM and RNSTs is ever improving.