http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Youngwoo Nam,Jung-Su Lee,Sang-Hyun Koh,Tae Su Kim,Sang-Gil Lee,Dae-Sung Won,Jong-Kuk Kim,Won Il Choi 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05
Spatio-temporal distribution pattern of an ambrosia beetle, Platypus koryoensis (Murayama) which is vector of Raffaeleaquerci-mongolicae K.H. Kim et al, a causative agent for Korean oak wilt (KOW) was examined in the stand level. Spatial distribution of P. koryoensiswas influenced by their density. Relationship between degree of aggregation and density was positively correlated when the density was extremely low or high whereas the relationship was reverse when the density was intermediate. Patch of P. koryoensis formed around or near dead trees or partial dead trees, suggesting these trees indicated epicenter of P. koryoensis. Fraction of trees attacked by less than 100 individual of P. koryoensis in the stand per year increased abruptly whereas fraction of trees attacked over 1,000 individuals of P. koryoensis increased gradually. Our results showed that the dead trees would be an epicenter of P. koryoensis and the number of trees killed by the ambrosia beetle would be reduced by lowering total population of the ambrosia beetle around the epicenter.
Through-Silicon Via Capacitance–Voltage Hysteresis Modeling for 2.5-D and 3-D IC
Kim, Dong-Hyun,Kim, Youngwoo,Cho, Jonghyun,Bae, Bumhee,Park, Junyong,Lee, Hyunsuk,Lim, Jaemin,Kim, Jonghoon J.,Piersanti, Stefano,de Paulis, Francesco,Orlandi, Antonio,Kim, Joungho IEEE 2017 IEEE transactions on components, packaging, and ma Vol.7 No.6
<P>We propose, for the first time, an explicit semiconductor physics-based through-silicon via (TSV) capacitance-voltage (CV) model. The effect of TSV CV hysteresis is demonstrated in the model, and the TSV capacitance is modeled with respect to dc bias voltage and the dimension of the TSV. The proposed model is verified by comparison to the measurement results. The effect of hysteresis in the model correlates well with the measurement results. This model can be utilized in a circuit level simulation to expand the possible application of the model to, but not limited to, hierarchical power distribution network impedance analysis, RC delay analysis, input-output power consumption analysis, and crosstalk and eye diagram simulation in any 3-D-IC systems using TSVs.</P>
Youngwoo Kim,Jonghyun Cho,Kyungjun Cho,Junyong Park,Subin Kim,Dong-Hyun Kim,Gapyeol Park,Sitaraman, Srikrishna,Raj, Pulugurtha Markondeya,Tummala, Rao R.,Joungho Kim IEEE 2017 IEEE transactions on components, packaging, and ma Vol.7 No.9
<P>In this paper, we propose glass-interposer (GI) electromagnetic bandgap (EBG) structure with defected ground plane (DGP) for efficient and broadband suppression of power/ground noise coupling. We designed, fabricated, measured, and analyzed a GI-EBG structure with DGP for the first time. The proposed GI-EBG structure with DGP is thoroughly analyzed using the dispersion characteristics and estimated stopband edges, f(L) and f(U). We experimentally verified that the proposed GI-EBG structure with DGP achieved power/ground noise isolation bandgap (below -30 dB) between f(L) of 5.7 GHz and f(U) of 11 GHz. Estimation of f(L) and f(U) using dispersion analysis, full 3-D electromagnetic (EM) simulation results, and measurement results achieved good correlation. Effectiveness of the proposed GI-EBG structure with DGP on suppression of the power/ground noise coupling to high-speed through glass via (TGV) channel is verified with 3-D EM simulation. As a result, the proposed EBG structure successfully and efficiently suppressed the power/ground noise coupling and improved the eye diagram of the TGV channel. Lastly, we embedded thin alumina film in the proposed EBG structure and achieved even broader power/ground noise suppression between 2.1 and 14.7 GHz.</P>
Kim, Jonghoon J.,Heegon Kim,Jung, Daniel H.,Sumin Choi,Jaemin Lim,Youngwoo Kim,Junyong Park,Hyesoo Kim,Dongho Ha,Bae, Michael,Joungho Kim IEEE 2017 IEEE transactions on electromagnetic compatibility Vol.59 No.4
<P>As the data rate of Low Power Double Data Rate 4 (LPDDR4) memory now exceeds 3.2 Gb/s, it is becoming more difficult to meet the target specifications. While testing has become of utmost importance, it is not viable to have a direct access to the signal pins in a package on package configuration due to the densely located array of solder balls; instead, a test interposer with an excellent electrical performance needs to be adopted to provide test access. In this paper, we first propose a novel test interposer scheme for testing LPDDR4 memory packages. For accurate testing without significant influence on the intrinsic signal path, the proposed test interposer is designed considering a number of signal integrity issues such as intersymbol interference, jitter, impedance matching, and crosstalk. Furthermore, by adopting silicone rubber sheet in place of soldering, the proposed test interposer enhances reusability of the packages with a fast setup time. Moreover, a reconstruction method is proposed that can reconstruct the voltage at application processor using the waveform captured on the test interposer, instead of probing at the ball gray array directly. Through a series of simulations and measurements, we experimentally verified the proposed test interposer. The proposed test interposer scheme can be widely adopted for testing of high-performance packages with its high accuracy and practicality.</P>
Kim, Jong-Man,Chu, Kyongtae,Lee, Sanghyo,Lee, Dong-Kyu,Kim, Yongsung,Kim, Jung-Mu,Baek, Chang-Wook,Kwon, Youngwoo,Kim, Yong-Kweon IOP 2006 Journal of micromechanics and microengineering Vol.16 No.10
<P>This paper describes two types of novel compact low-loss millimeter-wave filters using an overlay coplanar waveguide (OCPW) line for lowpass filters and an inverted overlay coplanar waveguide (IOCPW) line for bandpass filters with periodic defected ground structures (DGSs). The OCPW and IOCPW lines are utilized to reduce the conductor and the substrate dielectric loss of the transmission lines. Also, these lines can provide a wide impedance range by controlling the overlapped area. The DGSs implemented on the transmission line have the role of size reduction and harmonic suppression of the filters. The combination of transmission lines having suspended structures and DGSs can provide great potential in terms of compact size, band rejection property and low-loss characteristics. The proposed filters are fabricated by using a micromachining technology and their RF performances are measured and analyzed. One of the proposed filters is a lowpass filter with a five-section stepped impedance topology having a periodic high–low impedance section. In this filter, the low impedance section is composed of the OCPW line with dumbbell-shaped DGSs and its length can be reduced by 52.7% compared to the OCPW line without DGSs. The measured insertion loss of this filter is lower than 0.2 dB up to 9 GHz, and significant spurious bands are not observed up to 40 GHz, resulting in a wide stop band. The other work that is presented here deals with a pi-shaped bandpass filter. This filter consists of three high impedance sections and two low impedance sections, and the line length of the high impedance section can be reduced by using the IOCPW line with spiral-shaped DGSs. The measured center frequency of the fabricated filter is 19 GHz, and the passband loss is 2.3 dB at the measured center frequency. The use of DGSs on the transmission line also enables us to suppress effectively the third-order harmonic component at 57 GHz.</P>
Kim, Youngwoo,Cho, Jonghyun,Kim, Jonghoon J.,Cho, Kyungjun,Kim, Subin,Sitaraman, Srikrishna,Sundaram, Venky,Raj, Pulugurtha Markondeya,Tummala, Rao R.,Kim, Joungho [Institute of Electrical and Electronics Engineers 2017 IEEE transactions on electromagnetic compatibility Vol.59 No.3
<P>In this paper, we propose glass interposer electromagnetic bandgap (EBG) structure to efficiently suppress power/ground noise coupling. We designed, fabricated, measured, and analyzed a glass interposer EBG structure for the first time. Glass interposer EBG structure test vehicles were fabricated using a thin-glass substrate, low-loss polymer layers, and periodic metal patches with through glass vias (TGVs) in glass interposer power distribution network. Using the dispersion characteristics, we thoroughly analyzed and derived f(L) and f(U) of the glass interposer EBG structure. We experimentally verified that the proposed glass interposer EBG structure achieved power/ground noise suppression (below -40 dB) between f(L) of 5.8 GHz and f(U) of 9.6 GHz. Derived f(L) and f(U) based on dispersion analysis, full three-dimensional electromagnetic (3-D-EM) simulation and measurement achieved good correlation. In the glass interposer EBG structure, tapered structure of the TGV and thickness of the low-loss polymer used for metal-layers lamination affected the noise suppression bandgap significantly. The effectiveness of the proposed glass interposer EBG structure on suppression of the power/ground noise propagation and coupling to high-speed TGV channel was verified with 3-D-EM simulation. As a result, the proposed glass interposer EBG structure successfully and efficiently suppressed the power/ground noise propagation and improved eye-diagram of the high-speed TGV channel.</P>
Kim, Youngwoo,Hong, Byung Woo,Kim, Seung Ja,Kim, Jong Hyo Published for the American Association of Physicis 2014 Medical physics Vol.41 No.7
<P>A major challenge when distinguishing glandular tissues on mammograms, especially for area-based estimations, lies in determining a boundary on a hazy transition zone from adipose to glandular tissues. This stems from the nature of mammography, which is a projection of superimposed tissues consisting of different structures. In this paper, the authors present a novel segmentation scheme which incorporates the learned prior knowledge of experts into a level set framework for fully automated mammographic density estimations.</P>