http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A 4×32-Channel Neural Recording System for Deep Brain Stimulation Systems
Kim, Susie,Na, Seung-In,Yang, Youngtae,Kim, Hyunjong,Kim, Taehoon,Cho, Jun Soo,Kim, Jinhyung,Chang, Jin Woo,Kim, Suhwan The Institute of Electronics and Information Engin 2017 Journal of semiconductor technology and science Vol.17 No.1
In this paper, a $4{\times}32$-channel neural recording system capable of acquiring neural signals is introduced. Four 32-channel neural recording ICs, complex programmable logic devices (CPLDs), a micro controller unit (MCU) with USB interface, and a PC are used. Each neural recording IC, implemented in $0.18{\mu}m$ CMOS technology, includes 32 channels of analog front-ends (AFEs), a 32-to-1 analog multiplexer, and an analog-to-digital converter (ADC). The mid-band gain of the AFE is adjustable in four steps, and have a tunable bandwidth. The AFE has a mid-band gain of 54.5 dB to 65.7 dB and a bandwidth of 35.3 Hz to 5.8 kHz. The high-pass cutoff frequency of the AFE varies from 18.6 Hz to 154.7 Hz. The input-referred noise (IRN) of the AFE is $10.2{\mu}V_{rms}$. A high-resolution, low-power ADC with a high conversion speed achieves a signal-to-noise and distortion ratio (SNDR) of 50.63 dB and a spurious-free dynamic range (SFDR) of 63.88 dB, at a sampling-rate of 2.5 MS/s. The effectiveness of our neural recording system is validated in in-vivo recording of the primary somatosensory cortex of a rat.
Kim, Sookwan,De Santis, Laura,Hong, Jong Kuk,Cottlerle, Diego,Petronio, Lorenzo,Colizza, Ester,Kim, Young-Gyun,Kang, Seung-Goo,Kim, Hyoung Jun,Kim, Suhwan,Wardell, Nigel,Geletti, Riccardo,Bergamasco, Elsevier 2018 Marine geology Vol.395 No.-
<P><B>Abstract</B></P> <P>Sedimentation processes influenced by late Cenozoic ice-sheet dynamics and bottom-current activity can be extracted from the seismic stratigraphic record of the Ross Sea continental slope and rise, where more continuous sedimentary successions are preserved compared to the continental shelf. In this study, we present a seismic stratigraphic analysis of the Central Basin that lies in the northwestern Ross Sea, using newly acquired and existing legacy seismic reflection data that are correlated to adjacent scientific drill sites. The chronostratigraphy of Ross Sea seismic sequences lying above the mid-Miocene sequence boundary (RSU4, ca. 16.5–15.5Ma) is based on the former Antarctic Offshore Stratigraphy (ANTOSTRAT) project. Depth-contour and isopach maps of sedimentary sequences bounded by two major unconformities of RSU4 and RSU2 (the late Pliocene boundary, ca. 4.0–2.8Ma) and the present-day seafloor were produced to illustrate the evolution of paleo-seafloor morphology, distribution of sediments and depocenter migration in the western Ross Sea outer margin.</P> <P>The results of seismic stratigraphic analysis indicate that gravity sedimentation processes dominated the Central Basin infill up to the mid-Miocene, and then downslope sediment supply gradually diminished through the late Miocene and Quaternary, likely reflecting a shift toward a cooler, less erosive glacial regime change. Since the late Pliocene, a topset-truncated glacial prograding wedge developed in the upper continental slope at the mouth of the Joides Basin and the sediment depocenter was shifted from the basin floor to the upper slope, suggesting the more persistent occurrence of grounded ice sheets on the outer continental shelf. Meanwhile, persistent along-slope bottom-current processes formed contourites on the slope and over the crests of banks surrounding the Central Basin since the mid-Miocene. In the late Pliocene, the contourites that formed off the Joides Basin mouth were overlain by glaciogenic debris flows, while the growth of contourites continued over and along the flanks of banks, farther to the north. This suggests that along-slope bottom-current processes near the Joides Basin mouth were diminished or dominated by the glacial discharge to the continental shelf edge. The sediment stacking patterns differ between the Joides/Central Basins and the Drygalski/Adare Basins located on the westernmost Ross Sea margin, suggesting that distinctive glacial/interglacial behavior of the former grounded ice streams and sediment supplies in the troughs feeding these basins were largely controlled by the paleo-seafloor morphology of the western Ross Sea continental shelf.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First seismic stratigraphic analysis of the Central Basin, northwestern Ross Sea. </LI> <LI> Gravity and bottom-current controlled sedimentary features are observed. </LI> <LI> Distinctive paleo-seafloor morphology and depocenter migration are indicated. </LI> <LI> Ice sheet shifted toward polar-style glacial regime during the late Cenozoic. </LI> <LI> Bottom-current activity changed near the paleo-shelf edge after late Pliocene. </LI> </UL> </P>
황수환(Suhwan Hwang),김은수(EunSue Kim),이봉준(Bongjun Lee),김길주(Giljoo Kim),김동기(Donggi Kim),김승재(Seungjae Kim),이인호(Inho Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
It is the essential technique to detect the position of passenger head before rear collision for minimizing the passenger neck injury. This research introduces the technique of measuring distance between the head and headrest using the electrostatic capacity sensor in the headrest. According to the sensor material, the detecting performance of sensor was investigated. And the reliability was also tested with the new developed test-bench. On the other hand, the new mechanism is applied to the pre-crash headrest for moving the headrest front-upward. When the distance between the head rest and passenger head is measured accurately, pre-crash headrest could be adjusted to most proper position for Whiplash protection. New developed headrests can access passenger heads close to 10㎜ within 0.8 second.
A 4×32-Channel Neural Recording System for Deep Brain Stimulation Systems
Susie Kim,Seung-In Na,Youngtae Yang,Hyunjong Kim,Taehoon Kim,Jun Soo Cho,Jinhyung Kim,Jin Woo Chang,Suhwan Kim 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.1
In this paper, a 4×32-channel neural recording system capable of acquiring neural signals is introduced. Four 32-channel neural recording ICs, complex programmable logic devices (CPLDs), a micro controller unit (MCU) with USB interface, and a PC are used. Each neural recording IC, implemented in 0.18 mm CMOS technology, includes 32 channels of analog front-ends (AFEs), a 32-to-1 analog multiplexer, and an analog-to-digital converter (ADC). The midband gain of the AFE is adjustable in four steps, and have a tunable bandwidth. The AFE has a mid-band gain of 54.5 dB to 65.7 dB and a bandwidth of 35.3 Hz to 5.8 kHz. The high-pass cutoff frequency of the AFE varies from 18.6 Hz to 154.7 Hz. The input-referred noise (IRN) of the AFE is 10.2 mVrms. A high-resolution, low-power ADC with a high conversion speed achieves a signal-to-noise and distortion ratio (SNDR) of 50.63 dB and a spurious-free dynamic range (SFDR) of 63.88 dB, at a sampling-rate of 2.5 MS/s. The effectiveness of our neural recording system is validated in in-vivo recording of the primary somatosensory cortex of a rat.
microRNA-155 positively regulates glucose metabolism via PIK3R1-FOXO3a-cMYC axis in breast cancer
Kim, Sinae,Lee, Eunji,Jung, Jaeyun,Lee, Jong Won,Kim, Hee Jung,Kim, Jisun,Yoo, Hyun ju,Lee, Hee Jin,Chae, Sun Young,Jeon, Sang Min,Son, Byung Ho,Gong, Gyungyup,Sharan, Shyam K,Chang, Suhwan Nature Publishing Group UK 2018 Oncogene Vol.37 No.22
<P>MicroRNA is an endogenous, small RNA controlling multiple target genes and playing roles in various biological processes including tumorigenesis. Here, we addressed the function of miR-155 using LC-MS/MS-based metabolic profiling of miR-155 deficient breast cancer cells. Our results revealed the loss of miR-155 hampers glucose uptake and glycolysis, via the down-regulation of glucose transporters and metabolic enzymes including HK2, PKM2, and LDHA. We showed this is due to the down-regulation of cMYC, controlled through phosphoinositide-3-kinase regulatory subunit alpha (PIK3R1)-PDK1/AKT-FOXO3a pathway. UTR analysis of the PIK3R1 and FOXO3a indicated miR-155 directly represses these genes. A stable expression of miR-155 in patient-derived cells (PDCs) showed activated glucose metabolism whereas a stable inhibition of miR-155 reduced in vivo tumor growth with retarded glucose metabolism. Furthermore, analysis of 50 triple-negative breast cancer (TNBC) specimens and specific uptake value (SUV) of PET images revealed a positive correlation between miR-155 level and glucose usage in human breast tumors via PIK3R1-PDK/AKT-FOXO3a-cMYC axis. Collectively, these data demonstrate the miR-155 is a key regulator of glucose metabolism in breast cancer.</P>
Quantitative structural characterization of phosphatidylinositol phosphates from biological samples
Kim, Su Hee,Song, Ha Eun,Kim, Su Jung,Woo, Dong Cheol,Chang, Suhwan,Choi, Woo Gyun,Kim, Mi Jeong,Back, Sung Hoon,Yoo, Hyun Ju American Society for Biochemistry and Molecular Bi 2017 Journal of lipid research Vol.58 No.2
<P>The aspects of cellular metabolism controlled by phosphatidylinositol phosphates (PtdInsPs) have been broadly expanded, and these phospholipids have drawn tremendous attention as pleiotropic signaling molecules. PtdInsPs analysis using LC/MS/MS has remained challenging due to the strong hydrophilicity of these lipids. Multiple reaction monitoring (MRM) or a neutral loss scan has been performed to quantitatively measure PtdInsPs after chemical derivatization on the phosphate groups of inositol moieties. Only predefined PtdInsPs can be measured in MRM mode, and fatty acyl compositions of sn-1 and sn-2 positions of PtdInsPs cannot be obtained from a neutral loss scan. In our present study, we developed a simple LC/MS/MS method for structural identification of sn-1 and sn-2 fatty acids of PtdInsPs and their relative quantitation. Precursor ion scans of sn-1 monoacylglycerols (MAGs) of PtdInsPs provided structural information about the lipids, and ammonium adduction enhanced signal intensities of PtdInsPs. The relative amount of observed PtdInsPs in biological samples could be compared using chromatographic peak areas from the neutral loss scans. Using precursor ion scans of sn-1 MAG and neutral loss scans of headgroups, major PtdInsPs in cells and tissues were successfully identified with structural information of sn-1 and sn-2 fatty acids, and their relative amounts in different samples were compared.</P>
Emerging memory technologies for neuromorphic computing
Kim, Chul-Heung,Lim, Suhwan,Woo, Sung Yun,Kang, Won-Mook,Seo, Young-Tak,Lee, Sung-Tae,Lee, Soochang,Kwon, Dongseok,Oh, Seongbin,Noh, Yoohyun,Kim, Hyeongsu,Kim, Jangsaeng,Bae, Jong-Ho,Lee, Jong-Ho IOP 2019 Nanotechnology Vol.30 No.3
<P>In this paper, we reviewed the recent trends on neuromorphic computing using emerging memory technologies. Two representative learning algorithms used to implement a hardware-based neural network are described as a bio-inspired learning algorithm and software-based learning algorithm, in particular back-propagation. The requirements of the synaptic device to apply each algorithm were analyzed. Then, we reviewed the research trends of synaptic devices to implement an artificial neural network.</P>
Kim, Chul-Heung,Lee, Soochang,Woo, Sung Yun,Kang, Won-Mook,Lim, Suhwan,Bae, Jong-Ho,Kim, Jaeha,Lee, Jong-Ho IEEE 2018 IEEE transactions on electron devices Vol.65 No.5
<P>We investigate the characteristics of a synaptic imitation device using a thin-film transistor (TFT)-type NOR flash memory cell with a half-covered floating gate. The long-term potentiation (LTP) and long-term depression (LTD) required for the operation of the spike-timing-dependent plasticity (STDP) algorithm are implemented using the proposed pulse scheme. Unsupervised learning is successfully demonstrated by applying the STDP learning rule through software MATLAB simulation reflecting the LTP/LTD characteristics of the fabricated TFT-type NOR flash memory array. We present the learning and recognition processes of <TEX>$28\times28$</TEX> MNIST handwritten digit patterns. First, STDP learning in a single-neuron string ( <TEX>$784\times1$</TEX>) is investigated, after which STDP learning is demonstrated in a multineuron array ( <TEX>$784\times10$</TEX>) with a lateral inhibition function to demonstrate the ability of multipattern learning and recognition. Meanwhile, we investigate the key factors of STDP unsupervised learning. Finally, an approach is suggested to implement a hardware neural network using the conventional CMOS technology for STDP unsupervised learning as a visual pattern recognition system.</P>
Suhwan Kim 한국산업경영시스템학회 2015 한국산업경영시스템학회지 Vol.38 No.2
This paper deals with rescheduling on unrelated parallel-machines with compressible processing times, assuming that the arrival of a set of new jobs triggers rescheduling. It formulates this rescheduling problem as an assignment problem with a side constraint and proposes a heuristic to solve it. Computational tests evaluate the efficacy of the heuristic.