11,894 research outputs found
Automatic domain ontology extraction for context-sensitive opinion mining
Automated analysis of the sentiments presented in online consumer feedbacks can facilitate both organizations’ business strategy development and individual consumers’ comparison shopping. Nevertheless, existing opinion mining methods either adopt a context-free sentiment classification approach or rely on a large number of manually annotated training examples to perform context sensitive sentiment classification. Guided by the design science research methodology, we illustrate the design, development, and evaluation of a novel fuzzy domain ontology based contextsensitive opinion mining system. Our novel ontology extraction mechanism underpinned by a variant of Kullback-Leibler divergence can automatically acquire contextual sentiment knowledge across various product domains to improve the sentiment analysis processes. Evaluated based on a benchmark dataset and real consumer reviews collected from Amazon.com, our system shows remarkable performance improvement over the context-free baseline
A_4 flavour symmetry breaking scheme for understanding quark and neutrino mixing angles
We propose a spontaneous A_4 flavour symmetry breaking scheme to understand
the observed pattern of quark and neutrino mixing. The fermion mass eigenvalues
are arbitrary, but the mixing angles are constrained in such a way that the
overall patterns are explained while also leaving sufficient freedom to fit the
detailed features of the observed values, including CP violating phases. The
scheme realises the proposal of Low and Volkas to generate zero quark mixing
and tribimaximal neutrino mixing at tree-level, with deviations from both
arising from small corrections after spontaneous A_4 breaking. In the neutrino
sector, the breaking is A_4 --> Z_2, while in the quark and charged-lepton
sectors it is A_4 --> Z_3 = C_3. The full theory has A_4 completely broken, but
the two different unbroken subgroups in the two sectors force the dominant
mixing patterns to be as stated above. Radiative effects within each sector are
shown to deviate neutrino mixing from tribimaximal, while maintaining zero
quark mixing. Interactions between the two sectors -- "cross-talk" -- induce
nonzero quark mixing, and additional deviation from tribimaximal neutrino
mixing. We discuss the vacuum alignment challenge the scenario faces, and
suggest three generic ways to approach the problem. We follow up one of those
ways by sketching how an explicit model realising the symmetry breaking
structure may be constructed.Comment: 14 pages, no figures; v3: Section 5 rewritten to correct an error;
new section added to the appendix; added references; v4: minor change to
appendix C, version to be published by JHE
Macroeconomic instability in Hong Kong : internal and external factors
The paper examines the sources of macroeconomic instability in Hong Kong under the linked exchange rate regime. A prototype IS-LM model is estimated, with adaptation to the restrictions posed by the US dollar peg that has been in place in Hong Kong since 1983. Among all external and internal factors of instability examined, local Hong Kong interest rate is found to have a dominant effect on real GDP, price and money supply. Over the long run, however, the US interest rate is the driving force behind the Hong Kong interest rate. Foreign inflation also affects Hong Kong\u27s domestic demand and price stability, and domestic demand in itself also acts as a significant factor, although it is not as influential as the Hong Kong interest rate and import price. Furthermore, Hong Kong\u27s sound banking system has helped to create a stable currency demand environment for its economy, in spite of the fact that most Hong Kong residents hold both domestic and foreign currencies simultaneously The methodology and findings of the paper seem to provide a tenable framework for future research toward understanding the financial and monetary transmission mechanism in Hong Kong, and for improving the exchange rate regime
The GR2 gripper: an underactuated hand for open-loop in-hand planar manipulation
Performing dexterous manipulation of unknown objects with robot grippers without using high-fidelity contact sensors, active/sliding surfaces, or a priori workspace exploration is still an open problem in robot manipulation and a necessity for many robotics applications. In this paper, we present a two-fingered gripper topology that enables an enhanced predefined in-hand manipulation primitive controlled without knowing the size, shape, or other particularities of the grasped object. The in-hand manipulation behavior, namely, the planar manipulation of the grasped body, is predefined thanks to a simple hybrid low-level control scheme and has an increased range of motion due to the introduction of an elastic pivot joint between the two fingers. Experimental results with a prototype clearly show the advantages and benefits of the proposed concept. Given the generality of the topology and in-hand manipulation principle, researchers and designers working on multiple areas of robotics can benefit from the findings
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