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51.
Two experiments examined the disruption of feature-based selection in triple-conjunction search at multiple target transfers. In Experiment 1, after 10 training sessions, a new target possessing previous distractor features was introduced. This produced disruption in RT and fixation number, but no disruption in feature-based selection. Specifically, there was a tendency to fixate objects sharing the target's contrast polarity and shape and this did not change even upon transfer to the new target. In Experiment 2, 30 training sessions were provided with three target transfers. At the first transfer, the results replicated Experiment 1. Subsequent transfers did not produce disruption on any measure. These findings are discussed in terms of strength theory, Guided Search, rule-based approaches to perceptual learning, and the area activation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
Hong Kong is known as a migrant city because its population was sourced from mainland China, and because there has always been outflows of people to overseas countries, especially from the mid-1980s to mid-1990s. Emigration to mainland China has become a significant recent trend. This article discusses this phenomenon in the theoretical contexts of migration and trans-border residential development. It contends that the trend will intensify more quickly than other cross-border movements because the two systems are separated by a political border within one country, and because there are common cultural ties and rapid economic integration. 相似文献
53.
In order to extend the expressive power of deductive databases, a formula that can have existential quantifiers in prenex normal form in a restricted way is defined as an extended rule. With the extended rule, we can easily define a virtual view that requires a division operation of relational algebra to evaluate. The paper addresses a recursive query evaluation where at least one formula in a recursive rule set is of an extended rule. We investigate transformable recursions as well as four cases of non-transformable recursions of transitive-closure-like and linear type. The work reveals that occurrence of an existentially quantified variable in the extended recursive body predicate might dramatically limit the level of recursive search. In particular, the number of iterations to answer extended queries can be determined, independently of database contents 相似文献
54.
OBJECTIVE: The purpose of our study was to evaluate the effectiveness of MR imaging for showing the intrinsic anatomy of a peripheral nerve. Cadaver wrist specimens that included the median nerve were imaged with MR imaging at 3 T, then sectioned, stained, and inspected grossly and microscopically. The size, shape, and signal intensity of the sheath and axonal structures in the median nerve were identified in MR images by comparison with anatomic sections. CONCLUSION: This study suggests that MR imaging with sufficiently high-resolution techniques shows the internal structure of peripheral nerves. These results suggest that MR imaging may be a means to distinguish neuritis, tumor, degeneration, or fatty proliferation in a peripheral nerve and to evaluate the nerve before microsurgical anastomosis. 相似文献
55.
Motion based object tracking with mobile camera 总被引:4,自引:0,他引:4
Kyu Won Lee Seong Won Ryu Soo Jong Lee Kyu Tae Park 《Electronics letters》1998,34(3):256-258
An efficient algorithm which detects and tracks a moving object is proposed. The global motion energy caused by camera movement is eliminated by finding the maximal matching position with the cross-correlation value between two consecutive frames using the spiral scanning technique. The region of a moving object is segmented exactly by combining the results of the temporal derivatives and edge map from one image, and the actual centroid of the moving object is determined as the mid-point of the cumulative distribution of the projection profile of the region 相似文献
56.
Wen-Jen Ho Wen-Thong Chang 《Electronics letters》1998,34(5):433-434
A multi-layer multigrid algorithm for curve fitting in the wavelet domain is presented. This algorithm is achieved by applying a wavelet transform to each grid of the conventional multigrid structure. Using a wavelet transform, the convergent rate in each grid is improved and the total system can converge more quickly 相似文献
57.
Yo-Chuol Ho Ki-Hong Kim Floyd B.A. Wann C. Yuan Taur Lagnado I. O K.K. 《Solid-State Circuits, IEEE Journal of》1998,33(12):2066-2073
Four- and 13-GHz tuned amplifiers have been implemented in a partially scaled 0.1-1 μm CMOS technology on bulk, silicon-on-insulator (SOI), and silicon-on-sapphire (SOS) substrates. The 4-GHz bulk, SOI, and SOS amplifiers exhibit forward gains of 14, 11, and 12.5 dB and Fmin's of 4.5 (bulk) and 3.5 db (SOS). The 13-GHz SOS and SOI amplifiers exhibit gains of 15 and 5.3 dB and Funn's of 4.9 and 7.8 dB. The 4-GHz bulk amplifier has the highest resonant frequency among reported bulk CMOS amplifiers, while the 13-GHz SOS and SOI amplifiers are the first in a CMOS technology to have tuned frequencies greater than 10 GHz. These and other measurement results suggest that it may be possible to implement 20-GHz tuned amplifiers in a fully scaled 0.1-1 μm CMOS process 相似文献
58.
Eight-channel bidirectional WDM add/drop multiplexer 总被引:2,自引:0,他引:2
Keang-Po Ho Shien-Kuei Liaw 《Electronics letters》1998,34(10):947-948
The authors propose and demonstrate an eight-channel reconfigurable bidirectional wavelength division multiplexed (WDM) add-drop multiplexer in which all channels can be added/dropped independently in either direction. The performance of the bidirectional WDM add/drop multiplexer is experimentally studied for a data rate of 10 Gbit/s per channel, providing an overall capacity of 80 Gbit/s. It is found that the performance of the add/drop multiplexer is not degraded by a backward propagating signal 相似文献
59.
Thermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate) [copoly(ET/CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X‐ray analysis (EDX), X‐ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a = 9.98 A?, b = 8.78 A?, c = 12.93 A?, α = 97.4°, β = 96.1°, and γ = 90.8°, which is very close to that of poly(chloro‐p‐phenylene terephthlate) (PCPT) with the lattice constants of a = 9.51 A?, b = 8.61 A?, c = 12.73 A?, α = 96.8°, β = 95.4°, and γ = 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1286–1294, 2002; DOI 10.1002/app.10451 相似文献
60.