73 research outputs found
Provenance and depositional environments of the upper Permian-lowermost Triassic fluvial and lacustrine sandstones, Wutonggou low-order cycle, Bogda Mountains, NW China
This work integrates petrographic and fieldwork studies and documents the spatial and temporal distributions of compositions and textures of the upper Permian-lowermost Triassic fluvial-lacustrine sandstones, Wutonggou low-order cycle (WTG LC), Bogda Mountains, NW China. In the first part, three petrofacies are identified on the basis of the relative abundances of quartz, feldspar, and lithics and conglomerate compositions and paleocurrent directions are documented. These data indicate that rocks of the eastern North Tianshan Suture (ENTS) and rift shoulders were the provenance lithology. Moreover, the upsection changes of petrofacies and conglomerate compositions suggest that the lithology of ENTS changed. During approximately Wuchiapingian, the eastern part of ENTS included the subduction complex, whereas the western part contained the undissected volcanic arc. During approximately Changhsingian to early Induan, the eastern part of ENTS was dominated with the transitional volcanic arc and subordinate with the subduction complex, whereas the subduction complex was exposed in the western part of ENTS. The second part documents the textural characteristics of the sandstones of WTG LC. Textures of different petrofacies are different in grain size, sorting, roundness, and textural maturity, indicating provenance is a major control factor in sandstone textures. Moreover, each petrofacies is subdivided into littoral/beach, deltaic, and fluvial sedimentary facies, of which the textural characteristics are similar. This work improves our understanding of the nature and the unroofing history of ENTS and factors in controlling compositions and textures of fluvial-lacustrine sandstones --Abstract, page iv
Synchronous charge extraction and voltage inversion (SCEVI): a new efficient vibration-based energy harvesting scheme
This paper presents a new interface technique called synchronous charge extraction and voltage inversion (SCEVI), which consists of a synchronous inductor and a buck-boost converter for vibration-based energy harvesting using piezoelectric elements. The theoretical calculation of the harvested power obtained by using such a technique are proposed and compared with the so-called Standard, SECE (Synchronous Electric Charge Extraction), Parallel-SSHI (Parallel Synchronized Switch Harvesting on Inductor) and Series-SSHI (Series Synchronized Switch Harvesting on Inductor) methods commonly used in piezoelectric vibration-powered generator considering both constant displacement amplitude and force amplitude. From the harvested power point of view, SCEVI and Parallel – SSHI techniques are the better ones and each has its own merits. But the harvested power of SCEVI is independent of the load connected to the generator and Parallel – SSHI depend on the load resistance. The harvested power of SECE is also independent of the load, but the further experimental results show that the proposed SCEVI interface technique dramatically increases the harvested power by almost up to 150 % compared with the SECE method under the same amplitude of displacement excitation
ANTECEDENTS OF PROJECT IMPLEMENTATION SUCCESS IN CROWDFUNDING
Crowdfunding is emerging as a booming financing channel for entrepreneurs to raise money for their projects. However, crowdfunding project implementation has been a major challenge which does not gain enough attention in the current literature. This paper developed a research model to investigate the antecedents of crowdfunding project success measured in three dimensions, i.e., award (product) delivery timeliness, the extent to which the award meets the specifications (meeting specifications), and sponsor overall satisfaction. We conducted a survey in Demohour, one of the famous crowdfunding platforms in China, to test the proposed model. The findings suggested that compared with delivery timeliness, meeting specifications is of more importance to increase overall satisfaction. The results also revealed that crowdfunding project difficulty significantly reduces the implementation success. In addition, team experience plays an important role in improving project success. Project planning is also a critical predictor for delivery timeliness. Both of theoretical research and crowdfunding industrial practice can draw some enlightenment from this study
Not only Online Review but also its Helpfulness is Manipulated: Evidence from Peer to Peer Lending Forum
Online reviews have become proposed as useful information for consumers to make decision. Meanwhile, review manipulation will weaken the credibility of online reviews. Except manipulating the review text and rating, we propose that review helpfulness, an important signal for consumer to filter the reviews, could also be manipulated. This study thus explores the existence of review helpfulness manipulation and the relationship between firm quality and review manipulation. Based on a dataset from a review forum in www.wdzj.com which is the leading and largest portal of peer to peer lending industry in China, we get the following interesting results. First, due to the manipulation of review helpfulness, a manipulated positive review is more likely to receive higher helpfulness, while a manipulated negative is more likely to get lower helpfulness. Second, a manipulated review tends to be lower quality in terms of readability and word count, which are found as positive predictors for review helpfulness. Third, high quality firms tend to manipulate more positive reviews, and at the same time high quality firms will receive more negative manipulated reviews. This study extends current understanding about online review manipulation, thereby providing theoretical and practice implications
Isolation Mondrian Forest for Batch and Online Anomaly Detection
We propose a new method, named isolation Mondrian forest (iMondrian forest),
for batch and online anomaly detection. The proposed method is a novel hybrid
of isolation forest and Mondrian forest which are existing methods for batch
anomaly detection and online random forest, respectively. iMondrian forest
takes the idea of isolation, using the depth of a node in a tree, and
implements it in the Mondrian forest structure. The result is a new data
structure which can accept streaming data in an online manner while being used
for anomaly detection. Our experiments show that iMondrian forest mostly
performs better than isolation forest in batch settings and has better or
comparable performance against other batch and online anomaly detection
methods.Comment: Accepted for presentation at the IEEE International Conference on
Systems, Man, and Cybernetics (SMC) 2020. The first three authors contributed
equally to this wor
Synchronous charge extraction and voltage inversion (SCEVI): a new efficient vibration-based energy harvesting scheme
This paper presents a new interface technique called synchronous charge extraction and voltage inversion (SCEVI), which consists of a synchronous inductor and a buck-boost converter for vibration-based energy harvesting using piezoelectric elements. The theoretical calculation of the harvested power obtained by using such a technique are proposed and compared with the so-called Standard, SECE (Synchronous Electric Charge Extraction), Parallel-SSHI (Parallel Synchronized Switch Harvesting on Inductor) and Series-SSHI (Series Synchronized Switch Harvesting on Inductor) methods commonly used in piezoelectric vibration-powered generator considering both constant displacement amplitude and force amplitude. From the harvested power point of view, SCEVI and Parallel – SSHI techniques are the better ones and each has its own merits. But the harvested power of SCEVI is independent of the load connected to the generator and Parallel – SSHI depend on the load resistance. The harvested power of SECE is also independent of the load, but the further experimental results show that the proposed SCEVI interface technique dramatically increases the harvested power by almost up to 150 % compared with the SECE method under the same amplitude of displacement excitation
Synchronous charge extraction and voltage inversion (SCEVI): a new efficient vibration-based energy harvesting scheme
This paper presents a new interface technique called synchronous charge extraction and voltage inversion (SCEVI), which consists of a synchronous inductor and a buck-boost converter for vibration-based energy harvesting using piezoelectric elements. The theoretical calculation of the harvested power obtained by using such a technique are proposed and compared with the so-called Standard, SECE (Synchronous Electric Charge Extraction), Parallel-SSHI (Parallel Synchronized Switch Harvesting on Inductor) and Series-SSHI (Series Synchronized Switch Harvesting on Inductor) methods commonly used in piezoelectric vibration-powered generator considering both constant displacement amplitude and force amplitude. From the harvested power point of view, SCEVI and Parallel – SSHI techniques are the better ones and each has its own merits. But the harvested power of SCEVI is independent of the load connected to the generator and Parallel – SSHI depend on the load resistance. The harvested power of SECE is also independent of the load, but the further experimental results show that the proposed SCEVI interface technique dramatically increases the harvested power by almost up to 150 % compared with the SECE method under the same amplitude of displacement excitation
Entangled X-ray Photon Pair Generation by Free Electron Lasers
Einstein, Podolsky and Rosen's prediction on incompleteness of quantum
mechanics was overturned by experimental tests on Bell's inequality that
confirmed the existence of quantum entanglement. In X-ray optics, entangled
photon pairs can be generated by X-ray parametric down conversion (XPDC), which
is limited by relatively low efficiency. Meanwhile, free electron laser (FEL)
has successfully lased at X-ray frequencies recently. However, FEL is usually
seen as a classical light source, and its quantum effects are considered minor
corrections to the classical theory. Here we investigate entangled X-ray photon
pair emissions in FEL. We establish a theory for coherently amplified entangled
photon pair emission from microbunched electron pulses in the undulator. We
also propose an experimental scheme for the observation of the entangled photon
pairs via energy and spatial correlation measurements. Such an entangled X-ray
photon pair source is of great importance in quantum optics and other X-ray
applications.Comment: 13 pages, 3 figure
FATA-Trans: Field And Time-Aware Transformer for Sequential Tabular Data
Sequential tabular data is one of the most commonly used data types in
real-world applications. Different from conventional tabular data, where rows
in a table are independent, sequential tabular data contains rich contextual
and sequential information, where some fields are dynamically changing over
time and others are static. Existing transformer-based approaches analyzing
sequential tabular data overlook the differences between dynamic and static
fields by replicating and filling static fields into each transformer, and
ignore temporal information between rows, which leads to three major
disadvantages: (1) computational overhead, (2) artificially simplified data for
masked language modeling pre-training task that may yield less meaningful
representations, and (3) disregarding the temporal behavioral patterns implied
by time intervals. In this work, we propose FATA-Trans, a model with two field
transformers for modeling sequential tabular data, where each processes static
and dynamic field information separately. FATA-Trans is field- and time-aware
for sequential tabular data. The field-type embedding in the method enables
FATA-Trans to capture differences between static and dynamic fields. The
time-aware position embedding exploits both order and time interval information
between rows, which helps the model detect underlying temporal behavior in a
sequence. Our experiments on three benchmark datasets demonstrate that the
learned representations from FATA-Trans consistently outperform
state-of-the-art solutions in the downstream tasks. We also present
visualization studies to highlight the insights captured by the learned
representations, enhancing our understanding of the underlying data. Our codes
are available at https://github.com/zdy93/FATA-Trans.Comment: This work is accepted by ACM International Conference on Information
and Knowledge Management (CIKM) 202
StoryAnalogy: Deriving Story-level Analogies from Large Language Models to Unlock Analogical Understanding
Analogy-making between narratives is crucial for human reasoning. In this
paper, we evaluate the ability to identify and generate analogies by
constructing a first-of-its-kind large-scale story-level analogy corpus,
\textsc{StoryAnalogy}, which contains 24K story pairs from diverse domains with
human annotations on two similarities from the extended Structure-Mapping
Theory. We design a set of tests on \textsc{StoryAnalogy}, presenting the first
evaluation of story-level analogy identification and generation. Interestingly,
we find that the analogy identification tasks are incredibly difficult not only
for sentence embedding models but also for the recent large language models
(LLMs) such as ChatGPT and LLaMa. ChatGPT, for example, only achieved around
30% accuracy in multiple-choice questions (compared to over 85% accuracy for
humans). Furthermore, we observe that the data in \textsc{StoryAnalogy} can
improve the quality of analogy generation in LLMs, where a fine-tuned
FlanT5-xxl model achieves comparable performance to zero-shot ChatGPT.Comment: Accepted by EMNLP 2023 main conferenc
- …