59 research outputs found
Spatiotemporal Distribution of the Himalayan Leucogranite: Implications for Mountain-building as a Function of Indian Slab Dynamics
The Himalayan orogen, as a natural laboratory for continental collision, has attracted intense research attention for decades. However, the question of how the orogen was built is still debated, and potential answers are few when considering how and why along-strike variations of the mountain-building processes occurred. Various tectonic models have been proposed to explain the kinematics of the mountain-building. These models include two dimensional models, such as wedge extrusion (Burchfiel and Royden, 1985; Grujic et al., 1996; Kohn, 2008), channel flow coupled to focused denudation (Beaumont et al., 2001; Hodges et al., 2001), tectonic wedging (Yin, 2006; Webb et al., 2007), duplexing (He et al., 2015; Larson et al., 2015), and a recently proposed three dimensional model in which lateral migration of Indian slab detachment controlled the mountain building (Webb et al., submitted). Here, these models are tested by examining which model(s) can explain the generation of the leucogranites that occur along the orogen. The two-dimensional models predict that leucogranite ages and distributions should not vary significantly along the length of the orogeny, whereas the three-dimensional slab detachment model predicts that leucogranite generation should vary along-strike in specific ways, most notably by showing increasingly young minimum ages of large leucogranite bodies towards the east-central Himalaya. We compiled the existing geochronological data sets and estimated the volume of Himalayan leucogranites, revealing (1) increasing volumes and younging of leucogranite bodies from the ends of the orogen towards the east-central Himalaya, and (2) that younger leucogranite bodies appear generally larger than older emplaced bodies in any given range sector. These findings are generally consistent with the predictions of the lateral migration of slab detachment model, indicating that this model offers a viable explanation for the spatiotemporal distribution of Himalayan leucogranite. This interpretation prompts a re-evaluation of pre-existing two-dimensional models and confirms that Himalayan mountain building proceeded largely via duplexing, as modulated in three dimensions and time by the dynamics of the subducting Indian plate
M2C: Towards Automatic Multimodal Manga Complement
Multimodal manga analysis focuses on enhancing manga understanding with
visual and textual features, which has attracted considerable attention from
both natural language processing and computer vision communities. Currently,
most comics are hand-drawn and prone to problems such as missing pages, text
contamination, and aging, resulting in missing comic text content and seriously
hindering human comprehension. In other words, the Multimodal Manga Complement
(M2C) task has not been investigated, which aims to handle the aforementioned
issues by providing a shared semantic space for vision and language
understanding. To this end, we first propose the Multimodal Manga Complement
task by establishing a new M2C benchmark dataset covering two languages. First,
we design a manga argumentation method called MCoT to mine event knowledge in
comics with large language models. Then, an effective baseline FVP-M
using fine-grained visual prompts is proposed to support manga complement.
Extensive experimental results show the effectiveness of FVP-M method for
Multimodal Mange Complement.Comment: EMNLP2023. arXiv admin note: text overlap with arXiv:2210.1546
GripRank: Bridging the Gap between Retrieval and Generation via the Generative Knowledge Improved Passage Ranking
Retrieval-enhanced text generation, which aims to leverage passages retrieved
from a large passage corpus for delivering a proper answer given the input
query, has shown remarkable progress on knowledge-intensive language tasks such
as open-domain question answering and knowledge-enhanced dialogue generation.
However, the retrieved passages are not ideal for guiding answer generation
because of the discrepancy between retrieval and generation, i.e., the
candidate passages are all treated equally during the retrieval procedure
without considering their potential to generate the proper answers. This
discrepancy makes a passage retriever deliver a sub-optimal collection of
candidate passages to generate answers. In this paper, we propose the
GeneRative Knowledge Improved Passage Ranking (GripRank) approach, addressing
the above challenge by distilling knowledge from a generative passage estimator
(GPE) to a passage ranker, where the GPE is a generative language model used to
measure how likely the candidate passages can generate the proper answer. We
realize the distillation procedure by teaching the passage ranker learning to
rank the passages ordered by the GPE. Furthermore, we improve the distillation
quality by devising a curriculum knowledge distillation mechanism, which allows
the knowledge provided by the GPE can be progressively distilled to the ranker
through an easy-to-hard curriculum, enabling the passage ranker to correctly
recognize the provenance of the answer from many plausible candidates. We
conduct extensive experiments on four datasets across three knowledge-intensive
language tasks. Experimental results show advantages over the state-of-the-art
methods for both passage ranking and answer generation on the KILT benchmark.Comment: 11 pages, 4 figure
LogLG: Weakly Supervised Log Anomaly Detection via Log-Event Graph Construction
Fully supervised log anomaly detection methods suffer the heavy burden of
annotating massive unlabeled log data. Recently, many semi-supervised methods
have been proposed to reduce annotation costs with the help of parsed
templates. However, these methods consider each keyword independently, which
disregards the correlation between keywords and the contextual relationships
among log sequences. In this paper, we propose a novel weakly supervised log
anomaly detection framework, named LogLG, to explore the semantic connections
among keywords from sequences. Specifically, we design an end-to-end iterative
process, where the keywords of unlabeled logs are first extracted to construct
a log-event graph. Then, we build a subgraph annotator to generate pseudo
labels for unlabeled log sequences. To ameliorate the annotation quality, we
adopt a self-supervised task to pre-train a subgraph annotator. After that, a
detection model is trained with the generated pseudo labels. Conditioned on the
classification results, we re-extract the keywords from the log sequences and
update the log-event graph for the next iteration. Experiments on five
benchmarks validate the effectiveness of LogLG for detecting anomalies on
unlabeled log data and demonstrate that LogLG, as the state-of-the-art weakly
supervised method, achieves significant performance improvements compared to
existing methods.Comment: 12 page
HanoiT: Enhancing Context-aware Translation via Selective Context
Context-aware neural machine translation aims to use the document-level
context to improve translation quality. However, not all words in the context
are helpful. The irrelevant or trivial words may bring some noise and distract
the model from learning the relationship between the current sentence and the
auxiliary context. To mitigate this problem, we propose a novel end-to-end
encoder-decoder model with a layer-wise selection mechanism to sift and refine
the long document context. To verify the effectiveness of our method, extensive
experiments and extra quantitative analysis are conducted on four
document-level machine translation benchmarks. The experimental results
demonstrate that our model significantly outperforms previous models on all
datasets via the soft selection mechanism
xCoT: Cross-lingual Instruction Tuning for Cross-lingual Chain-of-Thought Reasoning
Chain-of-thought (CoT) has emerged as a powerful technique to elicit
reasoning in large language models and improve a variety of downstream tasks.
CoT mainly demonstrates excellent performance in English, but its usage in
low-resource languages is constrained due to poor language generalization. To
bridge the gap among different languages, we propose a cross-lingual
instruction fine-tuning framework (xCOT) to transfer knowledge from
high-resource languages to low-resource languages. Specifically, the
multilingual instruction training data (xCOT-INSTRUCT) is created to encourage
the semantic alignment of multiple languages. We introduce cross-lingual
in-context few-shot learning (xICL)) to accelerate multilingual agreement in
instruction tuning, where some fragments of source languages in examples are
randomly substituted by their counterpart translations of target languages.
During multilingual instruction tuning, we adopt the randomly online CoT
strategy to enhance the multilingual reasoning ability of the large language
model by first translating the query to another language and then answering in
English. To further facilitate the language transfer, we leverage the
high-resource CoT to supervise the training of low-resource languages with
cross-lingual distillation. Experimental results on previous benchmarks
demonstrate the superior performance of xCoT in reducing the gap among
different languages, highlighting its potential to reduce the cross-lingual
gap.Comment: 11 page
MT4CrossOIE: Multi-stage Tuning for Cross-lingual Open Information Extraction
Cross-lingual open information extraction aims to extract structured
information from raw text across multiple languages. Previous work uses a
shared cross-lingual pre-trained model to handle the different languages but
underuses the potential of the language-specific representation. In this paper,
we propose an effective multi-stage tuning framework called MT4CrossIE,
designed for enhancing cross-lingual open information extraction by injecting
language-specific knowledge into the shared model. Specifically, the
cross-lingual pre-trained model is first tuned in a shared semantic space
(e.g., embedding matrix) in the fixed encoder and then other components are
optimized in the second stage. After enough training, we freeze the pre-trained
model and tune the multiple extra low-rank language-specific modules using
mixture-of-LoRAs for model-based cross-lingual transfer. In addition, we
leverage two-stage prompting to encourage the large language model (LLM) to
annotate the multi-lingual raw data for data-based cross-lingual transfer. The
model is trained with multi-lingual objectives on our proposed dataset
OpenIE4++ by combing the model-based and data-based transfer techniques.
Experimental results on various benchmarks emphasize the importance of
aggregating multiple plug-in-and-play language-specific modules and demonstrate
the effectiveness of MT4CrossIE in cross-lingual
OIE\footnote{\url{https://github.com/CSJianYang/Multilingual-Multimodal-NLP}}.Comment: 10 page
Ultrawideband Frequency-Selective Absorber Designed with an Adjustable and Highly Selective Notch
In this paper, the working mechanism of a wideband absorber designed with an adjustable and highly selective notch band is studied, in which the narrow notch band is independently controlled by the lower lossless layer of the absorber, while the upper lossy layer loaded with lumped resistors realizes absorption. We present two instances with geometrically controlled and electrically controlled notch bands, respectively. Without decreasing absorption performance, the notch position can be flexibly adjusted throughout the entire frequency band by simply modifying the dimension of the lossless frequency-selective surface (FSS) or changing the capacitance of the varactor, i.e., using geometric control or electrical control. The narrow notch band allows two wide absorption bands to be retained on both sides; therefore, good stealth performance is still guaranteed. Equivalent circuit models (ECM) are proposed to further explain the principle. The frequency-domain simulation, ECM, time-domain simulation, and experimental results are in good agreement and validate the adjustability and high selectivity of the notched absorbers. At the end of this paper, an FSA-backed monopole antenna is simulated and measured, which clearly illustrates that these FSAs can serve as the ground plane for antennas and realize out-of-band RCS reduction
OWL: A Large Language Model for IT Operations
With the rapid development of IT operations, it has become increasingly
crucial to efficiently manage and analyze large volumes of data for practical
applications. The techniques of Natural Language Processing (NLP) have shown
remarkable capabilities for various tasks, including named entity recognition,
machine translation and dialogue systems. Recently, Large Language Models
(LLMs) have achieved significant improvements across various NLP downstream
tasks. However, there is a lack of specialized LLMs for IT operations. In this
paper, we introduce the OWL, a large language model trained on our collected
OWL-Instruct dataset with a wide range of IT-related information, where the
mixture-of-adapter strategy is proposed to improve the parameter-efficient
tuning across different domains or tasks. Furthermore, we evaluate the
performance of our OWL on the OWL-Bench established by us and open IT-related
benchmarks. OWL demonstrates superior performance results on IT tasks, which
outperforms existing models by significant margins. Moreover, we hope that the
findings of our work will provide more insights to revolutionize the techniques
of IT operations with specialized LLMs.Comment: 31 page
An Improved Equivalent Squint Range Model and Imaging Approach for Sliding Spotlight SAR Based on Highly Elliptical Orbit
As an emerging orbital system with flexibility and brand application prospects, the highly elliptical orbit synthetic aperture radar (HEO SAR) can achieve both a low orbit detailed survey and continuous earth surface observation in high orbit, which could be applied to marine reconnaissance and surveillance. However, due to its large eccentricity, two challenges have been faced in the signal processing of HEO SAR at present. The first challenge is that the traditional equivalent squint range model (ESRM) fails to accurately describe the entire range for the whole orbit period including the perigee, the apogee, and the squint subduction section. The second one is to exploit an efficient HEO SAR imaging algorithm in the squinted case which solves the problem that traditional imaging algorithm fails to achieve the focused imaging processing of HEO SAR during the entire orbit period. In this paper, a novel imaging algorithm for HEO SAR is presented. Firstly, the signal model based on the geometric configuration of the large elliptical orbit is established and the Doppler parameter characteristics of SAR are analyzed. Secondly, due to the particularity of Doppler parameters variation in the whole period of HEO, the equivalent velocity and equivalent squint angle used in MESRM can no longer be applied, a refined fourth-order equivalent squint range model(R4-ESRM) that is suitable for HEO SAR is developed by introducing fourth-order Doppler parameter into Modified ESRM (MESRM), which accurately reconstructs the range history of HEO SAR. Finally, a novel imaging algorithm combining azimuth resampling and time-frequency domain hybrid correlation based on R4-ESRM is derived. Simulation is performed to demonstrate the feasibility and validity of the presented algorithm and range model, showing that it achieves the precise phase compensation and well focusing
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