Picking battles: The impact of trust assumptions on the elaboration of security requirements

This position paper describes work on trust assumptions in the con-text of security requirements. We show how trust assumptions can affect the scope of the analysis, derivation of security requirements, and in some cases how functionality is realized. An example shows how trust assumptions are used by a requirements engineer to help define and limit the scope of analysis and to document the decisions made during the process

Nanosecond optical imaging spectroscopy of an electrothermal radiofrequency plasma thruster plume

Nanosecond optical imaging spectroscopy is employed to investigate the spatio-temporal dynamics of the plasma plume expanding from a 4.2 mm-diameter, 20 mm-long cylindrical capacitively coupled electrothermal radiofrequency (rf) driven thruster using 10 W of power at 12.50 MHz and an argon pressure of 1.5 Torr. On-axis, the plume exhibits four distinct peaks of optical emission intensity within the rf period. The plume has a spherical shape with a transient radial extension (during half of the rf cycle) at the thruster exit plane due to an rf current to ground when the grounded electrode acts as an anode

Formation of spatially periodic fronts of high-energy electrons in a radio-frequency driven surface microdischarge

The generation of spatially periodic fronts of high-energy electrons (>13.48 eV) has been investigated in a radio-frequency surface microdischarge in atmospheric-pressure argon. Optical emission spectroscopy is used to study the Ar I 2p1−1s2 transition surrounding a filamentary microdischarge, both spatially and with respect to the phase of the applied voltage. The formation of excitation fronts, which remain at a constant propagation distance throughout the RF cycle and for the duration of the pulse, may be explained by a localized increase in the electric field at the tip of surface-charge layers that are deposited during the extension phase

Wave-Measuring Performance Characteristics of Spoondrift Spotter

Spoondrift Spotter represents a state-of-the-art wave measurement buoy developed by Spoondrift (www.spoondrift.co) and supported by funding from the Advanced Research Projects Agency – Energy (ARPA-E). A low-cost buoy platform like Spotter enables a range of new applications. For instance, coherent arrays of Spotters can support adaptive tuning of marine and hydrokinetic energy devices. In general, the availability of high-fidelity wave measurements can help support wave assessments for a variety of commercial, military, operational, academic, and recreational users