• Title/Summary/Keyword: Sub-array

Search Result 417, Processing Time 0.027 seconds

4 Electrical Resistivity Probe for Investigating soft offshore soils (해안연약 지반 조사를 위한 4전극 전기비저항 프로브)

  • Kim, Joon-Han;Yoon, Hyung-Koo;Bae, Myeong-Ho;Jung, Soon-Hyuck;Lee, Jong-Sub
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2009.03a
    • /
    • pp.464-475
    • /
    • 2009
  • Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.

  • PDF

A Study on the Optimum Weight Vector of Linearly Constrained Conditions (선형 제한 조건의 최적 가중 벡터에 대한 연구)

  • Shin, Ho-Sub
    • Journal of the Korea Society of Computer and Information
    • /
    • v.16 no.5
    • /
    • pp.101-107
    • /
    • 2011
  • The optimum weight vector is studied to remove interference and jamming signals in adaptive array antenna system. The optimum weight vector is calculated to apply a minimum variance algorithm and cost function in linearly constrained conditions, and accurately estimates target's signal. Adaptive array antenna system is the system which improves signal to noise ratio(SNR) and decreases interference and jammer power. Adaptive array antenna system delays at tap output of antenna array element. Each tap finally makes the complex signal of one in multiplier complex weight. In order to obtain optimum's weight calculation, optimum weight vector is used in this paper. After simulation, resolution is increased below $3^{\circ}$, and sidelobe is decreased about 10 dB.

3D Microwave Imaging Technology for Damage Detection of Concrete Structures (콘크리트 구조물의 결함발견을 위한 3차원 초단파 영상처리기법의 개발)

  • Kim, Yoo-Jin;Kim, Yong-Gon
    • Journal of the Korean Society of Safety
    • /
    • v.18 no.4
    • /
    • pp.98-104
    • /
    • 2003
  • Various nondestructive evaluation (NDE) techniques have been studied to locate steel rebars of dowel, and to detect invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes. In this study, the aurhors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars of dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna array was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. This paper presents the analytical expressions of numerical focusing procedures for 3D image reconstruction and numerical simulation to study the resolution of the system and the effectiveness of multi-frequency technique. Also, the design of 4?4 antenna array with switching devices is introduced as a preliminary study for the final design of whole array.

Wave shape analysis of seismic records at borehole of TTRH02 and IWTH25 (KiK-net)

  • Kamagata, Shuichi
    • Earthquakes and Structures
    • /
    • v.18 no.3
    • /
    • pp.297-312
    • /
    • 2020
  • The KiK-net by NIED is a vertical array measurement system. In the database of KiK-net, singular pulse waves were observed in the seismic record at the borehole of TTRH02 during the mainshock (the magnitude of Japan Meteorological Agency (MJ) 7.3, MW 6.8) and aftershock (Mj 4.2) of Tottori-ken Seibu earthquake in 2000. Singular pulse waves were also detected in the seismic records at the borehole of IWTH25 during the Iwate-Miyagi Nairiku earthquake in 2008 (MJ 7.2, MW 6.9). These pulse waves are investigated by using the wave shape analysis methods, e.g., the non-stationary Fourier spectra and the double integrated displacement profiles. Two types of vibration modes are discriminated as the occurrence mechanism of the singular pulse waves. One corresponds to the reversal points in the displacement profile with the amplitude from 10-4 m to 10-1 m, which is mainly related to the fault activity and the amplification pass including the mechanical amplification (collision) of the seismograph in the casing pipe. The other is the cyclic pulse waves in the interval of reversal points, which is estimated as the backlash of the seismograph itself with the amplitude from 10-5 m to 10-4 m.

SOME NUMERICAL RADIUS INEQUALITIES FOR SEMI-HILBERT SPACE OPERATORS

  • Feki, Kais
    • Journal of the Korean Mathematical Society
    • /
    • v.58 no.6
    • /
    • pp.1385-1405
    • /
    • 2021
  • Let A be a positive bounded linear operator acting on a complex Hilbert space (𝓗, ⟨·,·⟩). Let ωA(T) and ║T║A denote the A-numerical radius and the A-operator seminorm of an operator T acting on the semi-Hilbert space (𝓗, ⟨·,·⟩A), respectively, where ⟨x, y⟩A := ⟨Ax, y⟩ for all x, y ∈ 𝓗. In this paper, we show with different techniques from that used by Kittaneh in [24] that $$\frac{1}{4}{\parallel}T^{{\sharp}_A}T+TT^{{\sharp}_A}{\parallel}_A{\leq}{\omega}^2_A(T){\leq}\frac{1}{2}{\parallel}T^{{\sharp}_A}T+TT^{{\sharp}_A}{\parallel}_A.$$ Here T#A denotes a distinguished A-adjoint operator of T. Moreover, a considerable improvement of the above inequalities is proved. This allows us to compute the 𝔸-numerical radius of the operator matrix $\(\array{I&T\\0&-I}\)$ where 𝔸 = diag(A, A). In addition, several A-numerical radius inequalities for semi-Hilbert space operators are also established.

A Study on the Imprinting Process for an Optical Interconnection of PLC Device (광소자의 광 정렬 및 연결 구조 구현용 임프린트 공정 연구)

  • Kim, Young Sub;Cho, Sang Uk;Kang, Ho Ju;Jeong, Myung Yung
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.29 no.12
    • /
    • pp.1376-1381
    • /
    • 2012
  • Optical devices are used extensively in the field of information network. Increasing demand for optical device, optical interconnection has been a important issue for commercialization. However many problems exist in the interconnection between optical device and optical fiber, and in the case of the multi-channel, problems of the optical alignment and optical array arise. For solving the alignment and array problem of optical device and the optical fiber, we fabricated fiber alignment and array by using imprint technology. Achieved higher precision of optical fiber alignment and array due to fabricating using imprint technology. The silicon stamp with different depth was fabricated using the conventional photolithography. Using the silicon stamp, a nickel stamp was fabricated by electroforming process. We conducted imprint process using the nickel stamp with different depth. The optical alignment and array by fabricating the patterns of optical device and fiber alignment and array using imprint process, and achieved higher precision of decreasing the dimensional error of the patterns by optimization of process. The fabricated optical interconnection of PLC device was measured 3.9 dB and 4.2 dB, lower than criteria specified by international standard.

Classification of Environmental Toxicants Using HazChem Human Array V2

  • An, Yu-Ri;Kim, Seung-Jun;Park, Hye-Won;Kim, Jun-Sub;Oh, Moon-Ju;Kim, Youn-Jung;Ryu, Jae-Chun;Hwang, Seung-Yong
    • Molecular & Cellular Toxicology
    • /
    • v.5 no.3
    • /
    • pp.250-256
    • /
    • 2009
  • Toxicogenomics using microarray technology offers the ability to conduct large-scale detections and quantifications of mRNA transcripts, particularly those associated with alterations in mRNA stability or gene regulation. In this study, we developed the HazChem Human Array V2 using the Agilent Sure-Print technology-based custom array, which is expected to facilitate the identification of environmental toxicants. The array was manufactured using 600 VOCs and PAHs-specific genes identified in previous studies. In order to evaluate the viability of the manufactured HazChem human array V2, we analyzed the gene expression profiles of 9 environmental toxicants (6 VOCs chemicals and 3 PAHs chemicals). As a result, nine toxicants were separated into two chemical types-VOCs and PAHs. After the chip validations with VOCs and PAHs, we conducted an expression profiling comparison of additional chemical groups (POPs and EDCs) using data analysis methods such as hierarchical clustering, 1-way ANOVA, SAM, and PCA. We selected 58 genes that could be classified into four chemical types via statistical methods. Additionally, we selected 63 genes that evidenced significant alterations in expression with all 13 environmental toxicants. These results suggest that the HazChem Human Array V2 will expedite the development of a screening system for environmentally hazardous materials at the level of toxicogenomics in the future.

A Read-In Integrated Circuit for IR Scene Projectors Adopting a Sub-Frame Control Technique for Minimizing the Temperature Loss (온도 손실의 최소화를 위해 Sub-Frame 제어 기법을 적용한 적외선 영상 투사기용 신호입력회로)

  • Shin, Uisub;Cho, Min Ji;Kang, Woo Jin;Jo, Young Min;Lee, Hee Chul
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.53 no.8
    • /
    • pp.113-118
    • /
    • 2016
  • In this paper, a read-in integrated circuit (RIIC) for IR scene projectors (IRSPs) adopting a sub-frame control technique is proposed, which minimizes the reduction of the apparent temperature of the IR images projected from IRSPs operating at a frame rate of 30 Hz. The proposed sub-frame control technique significantly reduces the amount of scene data loss on capacitors, which is caused by leakage currents flowing through MOSFET switches during holding periods, by dividing a unit frame into 8 sub-frames and refreshing the same scene data for each sub-frame. A current-drive RIIC was designed for the higher apparent temperature of IR radiated from the emitter, and it receives the scene data as a form of analog voltages from an external DAC. A prototype chip with a $64{\times}32$ RIIC array was fabricated using Magnachip/SKhynix $0.35{\mu}m$ 2-poly 4-metal CMOS process, and the measured maximum output data current is $230.3{\mu}A$. This amount of current ensures the projection of IR images whose maximum apparent temperature is $366.2^{\circ}C$ in the mid-wavelength IR (MWIR) when applied to a prototype emitter having a resistance of $15k{\Omega}$.

Enhanced Efficiency of Nanoporous-layer-covered TiO2 NanotubeArrays for Front Illuminated Dye-sensitized Solar Cells

  • Kang, Soon-Hyung;Lee, Soo-Yong;Kim, Jae-Hong;Choi, Chel-Jong;Kim, Hyunsoo;Ahn, Kwang-Soon
    • Journal of Electrochemical Science and Technology
    • /
    • v.7 no.1
    • /
    • pp.52-57
    • /
    • 2016
  • Nanoporous-layer-covered TiO2 nanotube arrays (Type II TNTs) were fabricated by two-step electrochemical anodization. For comparison, conventional TiO2 nanotube arrays (Type I TNTs) were also prepared by one-step electrochemical anodization. Types I and II TNTs were detached by selective etching and then transferred successfully to a transparent F-doped SnO2 (FTO) substrate by a sol-gel process. Both FTO/Types I and II TNTs allowed front side illumination to exhibit incident photon-to-current efficiencies (IPCEs) in the long wavelength region of 300 to 750 nm without the absorption of light by the iodine-containing electrolyte. The Type II TNT exhibited longer electron lifetime and faster charge transfer than the Type I TNT because of its relatively fewer defect states. These beneficial effects lead to a high overall energy conversion efficiency (5.32 %) of the resulting dye-sensitized solar cell.

A Comparison between J0 and J1 Digital Linear Filters in Resistivity Soundings (비저항탐사에서 J0 및 J1 디지탈 선형필터의 비교)

  • Kim, Hee Joon
    • Economic and Environmental Geology
    • /
    • v.18 no.1
    • /
    • pp.41-47
    • /
    • 1985
  • The filtering ability of $J_0$ and $J_1$ digital linear filters is compared by means of an adaptive linear filter. Any $J_0$ domain Hankel transform integral can be transformed mathematically into its corresponding $J_1$ domain integral. The apparent resistivities for any electrode configuration employed in resistivity soundings can be evaluated with a single $J_1$ filter. The $J_1$ filter usually has similar accuracy to, but shorter length than, the corresponding $J_0$ filter. The domain transformation from $J_0$ to $J_1$ enables us to use effective expressions of apparent resistivity, involving $J_1$ alone, not only for Schlumberger but also for dipole-dipole array.

  • PDF