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We consider the problem of controlling an unstable plant over an additive white Gaussian noise (AWGN) channel with a transmit power constraint, where the signaling rate of communication is larger than the sampling rate (for generating observations and applying control inputs) of the underlying plant. Such a situation is quite common since sampling is done at a rate that captures the dynamics of the plant and which is often much lower than the rate that can be communicated. This setting offers the opportunity of improving the system performance by employing multiple channel uses to convey a single message (output plant observation or control input). Common ways of doing so are through either repeating the message, or by quantizing it to a number of bits and then transmitting a channel coded version of the bits whose length is commensurate with the number of channel uses per sampled message. We argue that such "separated source and channel coding" can be suboptimal and propose to perform joint sourcechannel coding. Since the block length is short we obviate the need to go to the digital domain altogether and instead consider analog joint source-channel coding. For the case where the communication signaling rate is twice the sampling rate, we employ the Archimedean bi-spiral-based Shannon-Kotel'nikov analog maps to show significant improvement in stability margins and linear-quadratic Gaussian (LQG) costs over simple schemes that employ repetition.

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We present superconductor-insulator-normal metal (SIN) tunnel junction thermometers made of arrays of 4-100 Al-Al 2 O 3-Cu SIN tunnel junctions fabricated in direct-write technology. The technology is based on in situ evaporation of the superconductive electrode followed by the oxidation and the normal counter-electrode as a first step and deposition of normal metal absorber as a second one. This approach allows one to realize any geometry of the tunnel junctions and of the absorber with no limitation related to the size of the junctions or the absorber, which is not possible using the shadow evaporation technique. Measurements performed at 300 mK showed the high quality of the fabricated tunnel junctions, low leakage currents, and that an R d /R n ratio of 500 has been achieved at that temperature. The junctions were characterized as temperature sensors, and voltage versus temperature dependence measurements showed a dV /dT of 0.5 mV K −1 for each single junction, which is typical for this kind of tunnel junction. A temperature resolution of ±5 µK has been achieved which is much better than the previously reported value of ±30 µK for this type of thermometer.

Advances in propulsion systems are key to enabling independent deep-space CubeSat missions. Currently available electric propulsion technologies require relatively high power and thereby heavy power generation systems, severely limiting their utility for missions going away from the Sun. The ionic-liquid electrospray is known to have high power efficiency but a relatively short lifetime in its present state, limiting the total impulse available in such systems. This lifetime limit can be overcome by using several stages of thrusters, which are used in sequence to multiply the total system lifetime. In this paper, we present the design details and laboratory testing results for a staging system that is compatible with the CubeSat standard. This system will later be demonstrated in space on the STEP-1 satellite, which could enable an exciting new era of accessible CubeSat exploration around the solar system. Nomenclature= Effective exhaust velocity of propulsion system, m/s = Hold-down wire diameter, m = Elastic (Young's) modulus, Pa = Stiffness (spring constant), N/m = Hold-down wire length, m 0 = Spacecraft initial wet mass, kg dry = Propulsion system dry mass, kg pay = Spacecraft payload mass, kg P = Electrical power of propulsion system, W = Specific power of electricity generation, W/kg Δ = Velocity increment from propulsion, m/s

We demonstrate a novel ultrafast Multifocus 25-camera-array microscope (M25) for truly simultaneous high-resolution 3D imaging of 25 focal planes. Customized for functional neural circuit imaging, our M25 microscope captures 130× 130× 50um3 volumes at >100Hz.