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排序方式: 共有2362条查询结果,搜索用时 15 毫秒
21.
Bong Seok Park Jin Bae Park Yoon Ho Choi 《International Journal of Control, Automation and Systems》2011,9(3):534-541
In this paper, an adaptive observer-based trajectory tracking problem is solved for nonholonomic mobile robots with uncertainties.
An adaptive observer is first developed to estimate the unmeasured velocities of a mobile robot with model uncertainties.
Using the designed observer and the backstepping technique, a trajectory tracking controller is designed to generate the torque
as an input. Using Lyapunov stability analysis, we prove that the closed-loop system is asymptotically stable with respect
to the estimation errors and tracking errors. Finally, the simulation results are presented to validate the performance and
robustness of the proposed control system against uncertainties. 相似文献
22.
23.
Yong‐Kyu Jang Seong Jun Lee Jae Young Lee Yi Li Jae Hoon Hwang Sang Woo Kim Chang Woo Shim Ju Yeon Seo Nam Jin Kim Yi Joon Ahn Nam Hee Kim Seon Hong Ahn Seong Ryong Lee Dae Hee Park Chi Woo Kim 《Journal of the Society for Information Display》2011,19(3):253-257
Abstract— A novel pixel design for vertical‐alignment LCDs with superior transmittance has been developed. The new liquid‐crystal mode, refered to as the hole‐induced vertical‐alignment mode (Hi‐VA), uses a via hole of an organic layer on a TFT substrate to achieve multi‐domain alignment. Compared to the conventional design, the Hi‐VA mode has a transmittance of up to 135% with a contrast ratio of 2000:1. Moreover, the new structure is free from ITO patterning or protrusion on the color‐filter side, which makes the fabrication process simple and low cost. 相似文献
24.
Radio frequency identification (RFID) is viewed as a technology that improves supply chain efficiency by enhancing inventory
efficiency, optimizing logistics, and coordinating the flow of materials. Although RFID has gained great attention in many
business applications, the financial gain that accrues over time from RFID adoption is not well understood. We examine the
effects of RFID on firm profits while adjusting for self-selection of adoption choice. We find that firms self-select into
a certain adoption mode on the basis of their organizational characteristics. Our results also show that RFID confers significant
benefits for firms that have adopted RFID. Interestingly, improved inventory ratio and sales efficiency begin to play a greater
role in shaping higher profitability over time for firms that have adopted RFID possibly due to time-consuming processes for
them to reap the benefits from RFID. However, we find that the values of RFID that accrue to firms are not universal across
firm. That is, our results suggest that RFID confers a significant value for certain firms while it does not for other firms
with unobservable disadvantages. In sum, our study sheds new light on what drives firms to adopt RFID and on which firms achieve
higher financial performance in a post-adoption period as a result of RFID adoption. 相似文献
25.
Driving characteristics of the electrowetting-on-dielectric device using atomic-layer-deposited aluminum oxide as the dielectric 总被引:2,自引:1,他引:1
Jong-hyeon Chang Dae Young Choi Seungoh Han James Jungho Pak 《Microfluidics and nanofluidics》2010,8(2):269-273
Electrowetting on dielectric (EWOD) is useful in manipulating droplets for digital (droplet-based) microfluidics, but its high driving voltage over several tens of volts has been a barrier to overcome. This article presents the characteristics of EWOD device with aluminum oxide (Al2O3, ε r ≈ 10) deposited by atomic layer deposition (ALD), for the first time as the high-k dielectric for lowering the EWOD driving voltage substantially. The EWOD device of the single-plate configuration was fabricated by several steps for the control electrode array of 1 mm × 1 mm squares with 50 μm space, the dielectric layer of 1,270 Å thick ALD Al2O3, the reference electrode of 20 μm wide line electrode, and the hydrophobic surface treatment by Teflon-AF coating, respectively. We observed the movement of a 2 μl water droplet in an air environment, applying a voltage between one of the control electrodes and the reference electrode in contact with the droplet. The droplet velocity exponentially depending on the applied voltage below 15 V was obtained. The measured threshold voltage to move the droplet was as low as 3 V which is the lowest voltage reported so far in the EWOD researches. This result opens a possibility of manipulating droplets, without any surfactant or oil treatment, at only a few volts by EWOD using ALD Al2O3 as the dielectric. 相似文献
26.
Sang Min LeeAuthor VitaeJae Hwa SongAuthor Vitae Phill Gu JungAuthor VitaeDong Hyo JangAuthor Vitae Min Seong KimAuthor VitaeWeui Bong JeongAuthor Vitae Byung Min KimAuthor VitaeJong Soo KoAuthor Vitae 《Sensors and actuators. A, Physical》2011,171(2):233-240
A superhydrophobic micromesh covered with nanoprotrusions has been introduced and its applicability to a waterproof mobile phone speaker has been evaluated. The nanotextured superhydrophobic micromesh showed excellent water repellency, self-cleaning and waterproofing performances. In a waterproof speaker test using the fabricated nanotextured micromesh, the micromesh did not lose its waterproof function at 2 m water depth and did not form a remnant water film after being removed from the water. The packaged speaker showed almost the same sound quality before and after dipping at a 2 m water depth. These results demonstrate that the superhydrophobic nanotextured micromesh could be directly applicable for various products that need to resist water penetration, yet allow the transmission of gases and sound/light waves. 相似文献
27.
This study deals with a recycling system with two competing brewers. It is assumed that they coordinate their manufacturing operations through standardization of their glass bottles for easy implementation of extended producer responsibility (EPR). Immediate benefits from the standardization are three folds. Firstly, the sorting and exchange processes of the bottles collected for reuse by each brewer become no longer necessary. Secondly, cost reduction is achieved through streamlining of collection and reuse processes. Finally, under the stochastic demand of glass bottles their inventory holding costs and lost sales cost are reduced via inventory pooling. Through the development of the mathematical models we determine an optimal operation policy of the two brewers that maximizes the sum of benefits obtained from standardization. Numerical examples are solved to show the validity of the model. Sensitivity tests are also performed to examine the effects of system parameters on the objective function value and decision variables. 相似文献
28.
Bong Ban S. Baker Curtis L. Long Dale D. 《IEEE transactions on bio-medical engineering》1976,(1):75-77
A stimulator circuit is presented which is capable of generating pulse train waveforms suitable for neurophysiological experiments are available, as well as special test conditions such as dishabituation. Digital and linear integrated circuits are used to provide precise control over the stimulus parameters. 相似文献
29.
Sung Hwan Hwang Dae Dong Seo Jae Yong An Myeong-Hyun Kim Woo Chang Choi Sung Ryul Cho Sang Hwan Lee Hyo-Hoon Park Han Seo Cho 《Advanced Packaging, IEEE Transactions on》2006,29(3):457-462
We propose an advanced structure of optical subassembly (OSA) for packaging of the vertical-cavity surface-emitting laser (VCSEL) array, using (111) facet mirror of the V-groove ends formed in a silicon optical bench (SiOB) and angled fiber apertures. The feature of our OSA can provide a low optical crosstalk between neighboring channels, a low feedback reflection, and a large misalignment tolerance along the V-groove. We describe the optimized design of fiber angle, VCSEL position, and fiber position. The fabricated OSA structure consists of 12 channels of angled fiber array, 54.7/spl deg/ V-grooves, Au-coated mirrors on (111) end facet of the V-grooves, and flip-chip-bonded VCSEL array on a SiOB. In this structure, the beam emitted from the VCSEL is deflected at the 54.7/spl deg/ mirror of (111) end facet and propagated into the angled fiber. The angled fiber array was polished by 57/spl deg/. Fabricated OSAs showed a coupling efficiency of 30%-50% that is 25 times larger than that obtained from an OSA with a vertically flat fiber array. Our OSA showed large misalignment tolerance of about 90 /spl mu/m along the longitudinal direction in the V-groove. We fabricated a parallel optical transmitter module using the OSA and demonstrated 12 channels /spl times/2.5 Gb/s data transmission with a clear eye diagram. 相似文献
30.
Jumi Yun Dae Hoon Lee Ji Sun Im Hyung-Il Kim 《Materials science & engineering. C, Materials for biological applications》2012,32(6):1564-1570
Transdermal drug delivery system (TDDS) was prepared with temperature-responsive hydrogel. The graphite was oxidized and incorporated into hydrogel matrix to improve the thermal response of hydrogel. The micro heater was fabricated to control the temperature precisely by adopting a joule heating method. The drug in hydrogel was delivered through a hairless mouse skin by controlling temperature. The efficiency of drug delivery was improved obviously by incorporation of graphite oxide due to the excellent thermal conductivity and the increased interfacial affinity between graphite oxide and hydrogel matrix. The fabricated micro heater was effective in controlling the temperature over lower critical solution temperature of hydrogel precisely with a small voltage less than 1 V. The cell viability test on graphite oxide composite hydrogel showed enough safety for using as a transdermal drug delivery patch. The performance of TDDS could be improved noticeably based on temperature-responsive hydrogel, thermally conductive graphite oxide, and efficient micro heater. 相似文献