5 results on '"Dehghani, Morteza"'
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2. Incorporating Demographic Embeddings Into Language Understanding.
- Author
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Garten, Justin, Kennedy, Brendan, Dehghani, Morteza, Hoover, Joe, and Sagae, Kenji
- Abstract
Meaning depends on context. This applies in obvious cases like deictics or sarcasm as well as more subtle situations like framing or persuasion. One key aspect of this is the identity of the participants in an interaction. Our interpretation of an utterance shifts based on a variety of factors, including personal history, background knowledge, and our relationship to the source. While obviously an incomplete model of individual differences, demographic factors provide a useful starting point and allow us to capture some of this variance. However, the relevance of specific demographic factors varies between situations—where age might be the key factor in one context, ideology might dominate in another. To address this challenge, we introduce a method for combining demographics and context into situated demographic embeddings—mapping representations into a continuous geometric space appropriate for the given domain, showing the resulting representations to be functional and interpretable. We further demonstrate how to make use of related external data so as to apply this approach in low‐resource situations. Finally, we show how these representations can be incorporated into improve modeling of real‐world natural language understanding tasks, improving model performance and helping with issues of data sparsity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
3. Design and full-scale experimental evaluation of a seismically endurant steel buckling-restrained brace system.
- Author
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Dehghani, Morteza and Tremblay, Robert
- Subjects
EARTHQUAKE resistant design ,MECHANICAL buckling ,STEEL ,MECHANICAL loads ,ENERGY dissipation - Abstract
This paper presents the results of 12 full-scale tests on buckling-restrained brace (BRB) specimens. A simple-to-fabricate all-steel encasing joined by high-strength bolts was used as the buckling-restrainer mechanism. Steel BRBs offer significant energy dissipation capability through nondeteriorating inelastic response of an internal ductile core. However, seismic performance of BRBs is characterized by interaction between several factors. In this experimental study, the effects of core-restrainer interfacial condition, gap size, loading history, bolt spacing, and restraining capacity are evaluated. A simple hinge detail is introduced at the brace ends to reduce the flexural demand on the framing components. Tested specimens with bare steel contact surfaces exhibited satisfactory performance under the American Institute of Steel Construction qualification test protocol. The BRBs with friction-control self-adhesive polymer liners and a graphite-based dry lubricant displayed larger cumulative inelastic ductility under large-amplitude cyclic loading, exceeding current code minimum requirements. The BRB system is also examined under repeated fast-rate seismic deformation history. This system showed significant ductility capacity and remarkable endurance under dynamic loading. Furthermore, performance is qualified under long-duration loading history from subduction zone's megathrust type of earthquake. Predictable and stable performance of the proposed hinge detail was confirmed by the test results. Internally imposed normal thrust on the restrainer is measured using series of instrumented bolts. Weak- and strong-axis buckling responses of the core are examined. Higher post-yield stiffness was achieved when the latter governed, which could be advantageous to the overall seismic response of braced frames incorporating BRBs. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. Decoding the neural representation of story meanings across languages.
- Author
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Dehghani, Morteza, Boghrati, Reihane, Man, Kingson, Hoover, Joe, Gimbel, Sarah I., Vaswani, Ashish, Zevin, Jason D., Immordino‐Yang, Mary Helen, Gordon, Andrew S., Damasio, Antonio, and Kaplan, Jonas T.
- Abstract
Drawing from a common lexicon of semantic units, humans fashion narratives whose meaning transcends that of their individual utterances. However, while brain regions that represent lower-level semantic units, such as words and sentences, have been identified, questions remain about the neural representation of narrative comprehension, which involves inferring cumulative meaning. To address these questions, we exposed English, Mandarin, and Farsi native speakers to native language translations of the same stories during fMRI scanning. Using a new technique in natural language processing, we calculated the distributed representations of these stories (capturing the meaning of the stories in high-dimensional semantic space), and demonstrate that using these representations we can identify the specific story a participant was reading from the neural data. Notably, this was possible even when the distributed representations were calculated using stories in a different language than the participant was reading. Our results reveal that identification relied on a collection of brain regions most prominently located in the default mode network. These results demonstrate that neuro-semantic encoding of narratives happens at levels higher than individual semantic units and that this encoding is systematic across both individuals and languages. Hum Brain Mapp 38:6096-6106, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
5. Causal Explanation and Fact Mutability in Counterfactual Reasoning.
- Author
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DEHGHANI, MORTEZA, ILIEV, RUMEN, and KAUFMANN, STEFAN
- Subjects
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COUNTERFACTUALS (Logic) , *CAUSAL models , *REASONING , *BELIEF & doubt , *BAYESIAN analysis - Abstract
Recent work on the interpretation of counterfactual conditionals has paid much attention to the role of causal independencies. One influential idea from the theory of Causal Bayesian Networks is that counterfactual assumptions are made by intervention on variables, leaving all of their causal non-descendants unaffected. But intervention is not applicable across the board. For instance, backtracking counterfactuals, which involve reasoning from effects to causes, cannot proceed by intervention in the strict sense, for otherwise they would be equivalent to their consequents. We discuss these and similar cases, focusing on two factors which play a role in determining whether and which causal parents of the manipulated variable are affected: Speakers' need for an explanation of the hypothesized state of affairs, and differences in the 'resilience' of beliefs that are independent of degrees of certainty. We describe the relevant theoretical notions in some detail and provide experimental evidence that these factors do indeed affect speakers' interpretation of counterfactuals. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
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