김철 교수

Removal of motion artifacts is a critical challenge, especially in wearable electroencephalography (EEG) and photoplethysmography (PPG) devices that are exposed to daily movements. Recently, the significance of motion artifact removal techniques has increased since EEG-based brain–computer interfaces (BCI) and daily healthcare usage of wearable PPG devices were spotlighted. In this article, the development on EEG and PPG sensor systems is introduced. Then, understanding of motion artifact and it

Integrated recording of neural electrical potentials from the brain poses great challenges due to stringent dynamic range requirements to resolve small-signal amplitudes buried in noise amidst large artifact and stimulation transients, as well as stringent power and volume constraints to enable minimally invasive untethered operation. Here, we present a 16-channel neural recording system-on-chip with greater than 90-dB input dynamic range and less than 1-μVrms input-referred noise from dc to 500

This paper presents a fully integrated resonant regulating rectifier (IR <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) with an on-chip coil used to wirelessly power mm-sized implants. By combining rectification and regulation in a single stage, and controlling this stage via a hybrid pulse-width modulation and pulse-frequency modulation (PFM) feedback scheme, the IR <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://

A miniaturized, fully integrated wireless power receiver system-on-chip with embedded 16-channel electrode array and data transceiver for electrocortical neural recording and stimulation is presented. An H-tree power and signal distribution network throughout the SoC maintains high quality factor up to 11 in the on-chip receiver coil at 144 MHz resonant frequency while rejecting RF interference in sensitive neural interface circuits owing to its perpendicular and equidistant geometry. A multi-mo

A novel tunable all-digital, ultrawideband pulse generator (PG) has been implemented in a standard 0.18-¿ m complementary metal-oxide semiconductor (CMOS) process for implantable medical applications. The chip shows that an ultra-low dynamic energy consumption of 27 pJ per pulse without static current flow at a 200-MHz pulse repetition frequency (PRF) with a 1.8-V power supply and low area of 90 × 50 ¿m(2). The PG generates tunable pulsewidth, amplitude, and transmit (Tx) power by using simple c

One possible extension of the standard model scalar sector includes $SU(2{)}_{L}$ doublet scalars that are color octets rather than singlets. We focus on models in which the couplings to fermions are consistent with the principle of minimal flavor violation, in which case these color-octet scalars couple most strongly to the third generation of quarks. When the Yukawa coupling of color-octet scalars to standard model fermions is less than unity, these states can live long enough to bind into col

Although the Large Hadron Collider (LHC) has not observed supersymmetric (SUSY) partners of the Standard Model particles, their existence is not ruled out yet. One recently explored scenario in which there are light SUSY partners that have evaded current bounds from the LHC is that of a light long-lived stop quark. In this paper we consider light stop pair production at the LHC when the stop mass is between 200 and 400 GeV. If the stops are long-lived they can form a bound state, stoponium, whic

High-density multi-channel neural recording is critical to driving advances in neuroscience and neuroengineering through increasing the spatial resolution and dynamic range of brain-machine interfaces. Neural-signal-acquisition ICs have conventionally been designed composed of two distinct functional blocks per recording channel: a low-noise amplifier front-end (AFE), and an analog-digital converter (ADC) [1,2]. Hybrid architectures utilizing oversampling ADCs with digital feedback [3-5] have se

Chronic (repeated skin incisions) as well as acute stress (left adrenalectomy) was applied to rats whose hippocampus had been damaged through the neocortex (hippocampus-damaged), to rats in which only the portion of the neocortex over the hippocampus had been damaged (neocortex-damaged), and to control rats. Both in the acute and chronic stress series, the left adrenal ascorbic acid content before stress was compared with that of the right adrenal gland following stress, and the difference serve

A four-channel multi-input multi-output (MIMO) complex baseband receiver for spectrum and space-aware cognitive radio applications is presented. The MIMO baseband receiver comprises a capacitive harmonic-rejection downconverting mixer (HRM) receiver and a signal-separation multi-input multi-output analog core (MAC) on a single integrated circuit. The HRM receiver performs frequency selection of the incoming RF signals by programmable spectral downconversion and filtering with minimal harmonic fo

A continuum structure function is a non-decreasing mapping from the unit hypercube to the unit interval. A definition of the reliability importance, ℛ i (α) say, of component i at system level α(0 &lt; α ≦ 1) is proposed. Some properties of this function are deduced, in particular conditions under which and conditions under which ℛ i (α) is positive (0 &lt; α &lt; 1).

An adaptive buck-boost resonant regulating rectifier (B <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) with an integrated on-chip coil and low-loss H-Tree power/signal distribution is presented for efficient and robust wireless power transfer (WPT) over a wide range of input and load conditions. The B <sup xmlns:mml="http://www.w3.org/