A self-powered wearable
electrocardiography (ECG) system is demonstrated.
The ECG sensing circuit was fabricated on a flexible PCB and powered
by a wearable thermoelectric generator (w-TEG) using body heat as
the energy source. To allow the TEG to obtain a large temperature
difference for high power generation and also be wearable, a polymer-based
flexible heat sink (PHS) comprised of a superabsorbent polymer (SAP)
and a fiber that promotes liquid evaporation was devised. Parametric
studies on the PHS were conducted, and the structure of the w-TEG
was also optimized for the PHS. The output power density from the
w-TEG with the PHS was over 38 μW/cm2 for the first
10 min and over 13 μW/cm2 even after 22 consecutive
hours of driving the circuits. This power level is high enough to
continuously drive the wearable ECG system, including the sensors
and the power management circuits.
Frequency-modulated continuous-wave (FMCW) radars necessitate fast frequency modulation. However, finite loop bandwidth of a phase-locked loop (PLL) limits the accuracy of fast frequency modulation. This paper proposes a phase compensation (PC) technique to address this limitation. The synthesizer PLL with the PC technique realizes fast and precise triangular chirp modulation by adding a compensating square wave phase before the integral path of the loop filter. The synthesizer is designed in 130-nm SiGe BiCMOS technology. Simulation results show rms frequency error improvement of 18 times over conventional PLL with a chirp bandwidth of 2.56GHz and 20μs chirp period at 94GHz.
The main goal of this study is on developing a proper brand-new data of national base map and Data Based(DB) model for new information technology environments. To achieve this goal, we generated a brandnew Hybrid spatial information model which is specialized in the spatio-temporal map structure, the framework map for information integration, and the multiple-layered topology structure. The DB structure was designed to reflect the change of objections by adding a new dimension of 'time' in the spartial information, while the infrastructure was able to connect/converge with other information by giving the unique ID and multiscale fusion map structure. Furthermore, the topology and multi visualization structure, including indoor and basement information, were designed to overcome limitations of expressing in 2 dimension map. The result from the performance test, which was based on the Hybrid spatial information model, confirms the possibility in advanced national base map and conducted DB model through implementing various information and spatiotemporal connections.
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