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991.
J. -S. Sohn S. -H. Lee M. -S. Jung T. -S. Song N. -C. Park Y. -P. Park 《Microsystem Technologies》2005,11(7):457-463
We design an integrated optical pickup for small form factor optical disk drives. The specifications of the pickup are compatible with those of the Blu-ray disk (BD) in terms of numerical aperture (NA) of the objective lens, the wavelength of the laser diode, and the thickness of the cover layer. The objective lens unit with NA of 0.85 consists of two aspherical refractive lenses and a diffractive optical element for compensation of the chromatic aberration. Each element of objective lens unit will be fabricated on a wafer as an array type, and the three wafers will be aligned and bonded to form an objective lens array. Therefore, elements of the objective lens unit are designed to have sufficient alignment tolerances for various directions such as de-center and tilt. The optical performances of the objective lens unit are evaluated by simulation against various disturbances such as wavelength change of emitting light from laser diode, misalignments, etc. We also design a quarter wave plate, a polarized holographic optical element, and the shape of photodiode integrated circuit array to generate focusing and tracking error signals. The entire height of the pickup including working distance is 2 mm, and the effective pupil diameter of the objective lens unit is less than 1 mm. 相似文献
992.
An automated security management integrating various security systems is strongly required because cyber attacks are evolving
day after day. Moreover, the attacks are become more complex and intelligent than past. Several integrated security management
(ISM) models are supposed and implemented to meet the requirements. However, the current ISM is passive and behaves in a post-event
manner. To reduce costs and resources for managing security and to remove the possibility of an intruder succeeding in attacks,
the preventive security management technology is strongly required. This paper proposes the PRISM model that is based on tracing
important assets in a managed network and performs preventive security management before security incidents occur. Additionally,
PRISM model employs security labels to deploy differentiated security measure. The PRISM will provide concrete and effective
security management to the organization’s network. 相似文献
993.
Jeong‐Doo Yi Joon‐Yeon Kim Tae‐Woo Kim Hak‐Cheol Yang Jeong‐Nam Kim Yoon‐Hyoung Cho 《Journal of the Society for Information Display》2005,13(11):883-888
Abstract— We propose a PDP having a new structure and driving scheme. An auxiliary electrode was inserted between X and Y electrodes. Driving and discharge stability was determined using a test panel. A 42‐in. SD (852 × 480) panel and a 42‐in. HD (1366 × 768) panel were also made having this new structure, and we verified the increase in luminous efficacy and the reduction of ionic losses. We achieved a luminous efficacy of 2.35 lm/W in an SD panel and 1.97 lm/W in a HD panel. Finally, we investigated the characteristics and merits of the new structure. 相似文献
994.
Moon Gi Cho Kyung Wook Paik Hyuck Mo Lee Seong Woon Booh Tae-Gyu Kim 《Journal of Electronic Materials》2006,35(1):35-40
The interfacial reaction between 42Sn-58Bi solder (in wt.% unless specified otherwise) and electroless Ni-P/immersion Au was
investigated before and after thermal aging, with a focus on the formation and growth of an intermetallic compound layer,
consumption of under bump metallurgy (UBM), and bump shear strength. The immersion Au layer with thicknesses of 0 μm (bare
Ni), 0.1 μm, and 1 μm was plated on a 5-μm-thick layer of electroless Ni-P (with 14–15 at.% P). The 42Sn-58Bi solder balls
were then fabricated on three different UBM structures by using screen printing and pre-reflow. A Ni3Sn4 layer formed at the joint interface after the pre-reflow for all three UBM structures. On aging at 125°C, a quaternary phase,
identified as Sn77Ni15Bi6Au2, was observed above the Ni3Sn4 layer in the UBM structures that contain Au. The thick Sn77Ni15Bi6Au2 layer degraded the integrity of the solder joint, and the shear strength of the solder bump was about 40% less than the nonaged
joints. 相似文献
995.
Novel Approach to Integration of Numerical Modeling and Field Observations for Deep Excavations 总被引:1,自引:0,他引:1
Youssef M. A. Hashash Camilo Marulanda Jamshid Ghaboussi Sungmoon Jung 《Canadian Metallurgical Quarterly》2006,132(8):1019-1031
Precedent and observation of performance are an essential part of the design and construction process in geotechnical engineering. For deep urban excavations designers rely on empirical data to estimate potential deformations and impact on surrounding structures. Numerical simulations are also employed to estimate induced ground deformations. Significant resources are dedicated to monitor construction activities and control induced ground deformations. While engineers are able to learn from observations, numerical simulations have been unable to fully benefit from information gained at a given site or prior excavation case histories in the same area. A novel analysis method, self-learning in engineering simulations (SelfSim), is introduced to integrate precedent into numerical simulations. SelfSim is an inverse analysis technique that combines finite element method, biologically inspired material models, and field measurements. SelfSim extracts relevant constitutive soil information from field measurements of excavation response such as lateral wall deformations and surface settlement. The resulting soil model, used in a numerical analysis, provides correct ground deformations and can be used in estimating deformations of similar excavations. The soil model can continuously evolve using additional field information. SelfSim is demonstrated using two excavation case histories in Boston and Chicago. 相似文献
996.
High fill-factor two-axis gimbaled tip-tilt-piston micromirror array actuated by self-Aligned vertical electrostatic combdrives 总被引:1,自引:0,他引:1
Il Woong Jung Krishnamoorthy U. Solgaard O. 《Journal of microelectromechanical systems》2006,15(3):563-571
In this paper, we present a high fill-factor micromirror array actuated by self-aligned vertical electrostatic combdrives. To meet the requirements of applications in free-space communication and imaging, each micromirror has three degrees of freedom of motion: rotation around two axes in the mirror plane and linear translation perpendicular to the mirror plane. Our approach is to integrate the high fill-factor reflectors into the fabrication process of the actuators on the wafer-scale. Multilevel silicon-on-insulator (SOI) bonding is utilized to form the high optical quality reflectors and high aspect-ratio vertical combdrive actuators. The wiring for electrical access to the multielectrode per pixel array is fabricated on separate wafers by thin film processing, and flip-chip bonded to the reflector/actuator chip. This architecture overcomes the fill-factor limitation of top-side accessed electrical addressing of mirrors made on SOI. Our 360/spl mu/m pixel size mirror array achieves a 99% fill-factor with optically flat reflectors. 相似文献
997.
Sung-Won Jung Hyuk-Chul Kwon 《Knowledge and Data Engineering, IEEE Transactions on》2006,18(2):174-187
We have established a preprocessing method for determining the meaningfulness of a table to allow for information extraction from tables on the Internet. A table offers a preeminent clue in text mining because it contains meaningful data displayed in rows and columns. However, tables are used on the Internet for both knowledge structuring and document design. Therefore, we were interested in determining whether or not a table has meaningfulness that is related to the structural information provided at the abstraction level of the table head. Accordingly, we: 1) investigated the types of tables present in HTML documents, 2) established the features that distinguished meaningful tables from others, 3) constructed a training data set using the established features after having filtered any obvious decorative tables, and 4) constructed a classification model using a decision tree. Based on these features, we set up heuristics for table head extraction from meaningful tables, and obtained an F-measure of 95.0 percent in distinguishing meaningful tables from decorative tables and an accuracy of 82.1 percent in extracting the table head from the meaningful tables. 相似文献
998.
A shared disks (SD) cluster couples multiple computing nodes for high performance transaction processing, and all nodes share
a common database at the disk level. In the SD cluster, a front-end router selects a node for an incoming transaction to be
executed. An affinity-based routing can increase the buffer hit ratio of each node by clustering transactions referencing
similar data to be executed on the same node. However, the affinity-based routing is non-adaptive to the changes of the system
load. This means that a specific node would be overloaded if corresponding transactions rush into the system. In this paper,
we propose a new transaction routing algorithm, named Dynamic Affinity Cluster Allocation (DACA). DACA can make an optimal balance between the affinity-based routing and indiscriminate sharing of load in the SD
cluster. As a result, DACA can increase the buffer hit ratio and reduce the frequency of inter-node buffer invalidations while
achieving the dynamic load balancing. 相似文献
999.
Doo-Yeoun Cho Author Vitae Author Vitae Tae-Wan Kim Author Vitae 《Computer aided design》2006,38(6):641-660
We propose a local method of constructing piecewise G1 Bézier patches to span an irregular curve network, without modifying the given curves at odd- and 4-valent node points. Topologically irregular regions of the network are approximated by implicit surfaces, which are used to generate split curves, which subdivide the regions into triangular and/or rectangular sub-regions. The subdivided regions are then interpolated with Bézier patches. We analyze various singular cases of the G1 condition that is to be met by the interpolation and propose a new G1 continuity condition using linear and quartic scalar weight functions. Using this condition, a curve network can be interpolated without modification at 4-valent nodes with two collinear tangent vectors, even in the presence of singularities. We demonstrate our approach in a ship hull. 相似文献
1000.