2,215 research outputs found
The yamabe problem and related topics.
No full textPoon Chi Cheung.Bibliography: leaves 66-69Thesis (M.Ph.)--Chinese University of Hong Kong, 198
Business negotiation in China.
No full textLin Yan-Sun, Poon Po-Kit.Thesis (M.B.A.)--Chinese University of Hong Kong, 1985.Bibliography: leaf 66
Investors' rationality during the crash
No full textby Ho Chi Sze, Grace, Poon Chun Pong, Daniel, Wong Wai Ming.Thesis (M.B.A.)--Chinese University of Hong Kong, 1989.Bibliography: leaves 163-164
Stream-based Hebbian Eigenfilter for real-time neuronal spike discrimination
No full textBackground Principal component analysis (PCA) has been widely employed for automatic neuronal spike sorting. Calculating principal components (PCs) is computationally expensive, and requires complex numerical operations and large memory resources. Substantial hardware resources are therefore needed for hardware implementations of PCA. General Hebbian algorithm (GHA) has been proposed for calculating PCs of neuronal spikes in our previous work, which eliminates the needs of computationally expensive covariance analysis and eigenvalue decomposition in conventional PCA algorithms. However, large memory resources are still inherently required for storing a large volume of aligned spikes for training PCs. The large size memory will consume large hardware resources and contribute significant power dissipation, which make GHA difficult to be implemented in portable or implantable multi-channel recording micro-systems. Method In this paper, we present a new algorithm for PCA-based spike sorting based on GHA, namely stream-based Hebbian eigenfilter, which eliminates the inherent memory requirements of GHA while keeping the accuracy of spike sorting by utilizing the pseudo-stationarity of neuronal spikes. Because of the reduction of large hardware storage requirements, the proposed algorithm can lead to ultra-low hardware resources and power consumption of hardware implementations, which is critical for the future multi-channel micro-systems. Both clinical and synthetic neural recording data sets were employed for evaluating the accuracy of the stream-based Hebbian eigenfilter. The performance of spike sorting using stream-based eigenfilter and the computational complexity of the eigenfilter were rigorously evaluated and compared with conventional PCA algorithms. Field programmable logic arrays (FPGAs) were employed to implement the proposed algorithm, evaluate the hardware implementations and demonstrate the reduction in both power consumption and hardware memories achieved by the streaming computing Results and discussion Results demonstrate that the stream-based eigenfilter can achieve the same accuracy and is 10 times more computationally efficient when compared with conventional PCA algorithms. Hardware evaluations show that 90.3% logic resources, 95.1% power consumption and 86.8% computing latency can be reduced by the stream-based eigenfilter when compared with PCA hardware. By utilizing the streaming method, 92% memory resources and 67% power consumption can be saved when compared with the direct implementation of GHA. Conclusion Stream-based Hebbian eigenfilter presents a novel approach to enable real-time spike sorting with reduced computational complexity and hardware costs. This new design can be further utilized for multi-channel neuro-physiological experiments or chronic implants.Engineering and Physical Sciences Research Council (EPSRC grant EP/E044662/1)National Natural Science Foundation (China) ( grant 61006021)National Natural Science Foundation (China) (grant 4112029)National Institutes of Health (U.S.) (Grant HL067966)National Institutes of Health (U.S.) (Grant RR028241
Street football and community.
No full textPoon Chi Wa."Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2005-2006, design report."Chapter 1. --- The IssueChapter 2. --- InterviewChapter 3. --- Hong Kong Public Housing Study - The Evolution of Open spaceChapter 4. --- Neighbourhood Scale - Street Football StudyHong Kong and Foreign Street Football SpaceChapter 5. --- Urban Scale Hong Kong Street Football Study"Study of Southom Football Pitch, Wanchai"Chapter 6. --- Spatial Analysis of Football ActivityChapter 7. --- Site Analysis and ProgrammeChapter 8. --- Design Intentions and ConceptsChapter 9. --- The Final Desig
Nonassociative Learning
No full textNonassociative learning is an implicit (non-declarative) or procedural form of learning that systematically attenuates (habituates) or augments (sensitizes) an animal’s sensory percept or behavioral response to a sensory stimulus upon repeated or continual presentation of the stimulus. It differs from associative learning in that it does not require the temporal pairing between two different sensory stimuli or between a sensory stimulus and corresponding response feedback. It is considered a fundamental form of learning that can be observed across all animal phyla and most sensory modalities. It may also be regarded as one of the simplest forms of unsupervised learning in animals, in that it automatically classifies the valence of a sensory input based upon its temporal pattern without the need for a supervisory signal. In most animal species including humans, habituation and sensitization take place in sensory and sensorimotor pathways and provide an important central adaptation and gating mechanism for selective suppression or amplification of sensory information reaching higher centers of the brain or their effector organs
Low-power 3D integration using inductive coupling links for neurotechnology applications
No full textThree dimensional system integration offers the ability to stack multiple dies, fabricated in disparate technologies, within a single IC. For this reason, it is gaining popularity for use in sensor devices which perform concurrent analogue and digital processing, as both analogue and digital dies can be coupled together. One such class of devices are closed-loop neuromodulators; neurostimulators which perform real-time digital signal processing (DSP) to deliver bespoke treatment. Due to their implantable nature, these devices are inherently governed by very strict volume constraints, power budgets, and must operate with high reliability. To address these challenges, this paper presents a low-power inductive coupling link (ICL) transceiver for 3D integration of digital CMOS and analogue BiCMOS dies for use in closed-loop neuromodulators. The use of an ICL, as opposed to through silicon vias (TSVs), ensures high reliability and fabrication yield in addition to circumventing the use of voltage level conversion between disparate dies, improving power efficiency. The proposed transceiver is experimentally evaluated using SPICE as well as nine traditional TSV baseline solutions. Results demonstrate that, whilst the achievable bandwidth of the TSV-based approaches is much higher, for the typical data rates demanded by neuromodulator applications (0.5 - 1 Gbps) the ICL design consumes on average 36.7% less power through avoiding the use of voltage level shifters
Worship and Culture: Foreign Country or Homeland? (Gláucia Vasconcelos Wilkey)
No full textHoiling Poon considers this multi-author overview of a seven-year project by the Lutheran World Federation
Effect of herbal extract on rat bone marrow stromal derived osteoblast growth and differentiation in vitro / Poon Chi Tat
No full textDrynaria quercifolia (D.quercifolia) and Justicia gendarussa (J.gendarussa) are locally found herbs. Proper scientific studies were initiated to test the effects of the two plants and a pre-mixed herbal formulation (Bo-Gu-Cao formulation) with J.gendarussa as the main constituent. Rat bone marrow derived osteoblasts (rBMS-derived osteoblasts) were used as research subject in the present study. The effects of the herbal extracts on the cells were evaluated by comparing cell number and alkaline phosphatase (ALP) activity of the tested cells to control.
Samples of D.quercifolia, J.gendarussa, and pre-mixed Bo-Gu-Cao formulation were dried, powdered, and extracted with solvents of different polarities. Herbal extracts were reconstituted in media (at a concentration of 100 μg/ml) and subjected to proliferation rate, ALP activity evaluation, and staining of calcium deposition. Bone marrow stromal cells were isolated from tibias and femora of Sprague Dawley rats and subsequently induced to osteogenic differentiation. The cells were identified as bone marrow stromal cells prior to osteogenic differentiation by standard stem cell characterization. Cells were incubated with herbal extracts and evaluated with proliferation rate and ALP activity. Statistical analysis was performed by using One-Way ANOVA test to compare the means of samples and control values.
A total of 12 herbal extracts were obtained from the two herbs and the pre-mixed herbal formulation. Bone marrow stromal cells were identified as the microscopic observation confirmed attachment to plastic surface and fibroblastic morphology, characterized by CD90+, CD45- and CD31-, and the cells were able to be induced to osteoblasts, chondrocytes, and adipocytes. Calcium deposition by rBMS derived osteoblasts was stained by Alizarin Red S staining.Water extract of D.quercifolia and water extract of J.gendarussa and Bo-Gu-Cao formulation consistently induced a significant enhancement on rBMS derived osteoblast proliferation on day 7 and day 14 of incubation. ALP activity was enhanced significantly in the cells incubated with water extract of D.quercifolia and J.gendarussa for 7 days and 21 days. The dose dependency effect evaluation had shown the optimum dosage for D.quercifolia water extract, while there is no dose dependency effect found on water extract of J.gendarussa. The results of the present study reveals that the medicinal herbs used in this study possess certain substance/s that can enhance osteoblast proliferation as well as differentiation and can be postulated in aiding bone healing.
It can be concluded that water extract of D.quercifolia and J.gendarussa are the potential herbal extracts to be further investigated. Isolation of active compounds from D.quercifolia and J.gendarussa are to be done and effects of the active compounds on osteoblasts are to be evaluated
Dataset supporting the paper entitled “Low-Power 3D Integration using Inductive Coupling Links for Neurotechnology Applications"
No full textThis dataset supports the article entitled 'Low-Power 3D Integration using Inductive Coupling Links for Neurotechnology Applications' accepted for publication in Design, Automation & Test in Europe Conference & Exhibition (DATE), Dresden, 2018.</span
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