241 research outputs found
Compact Planar Sparse Array Antenna with Optimum Element Dimensions for SATCOM Ground Terminals
A novel antenna array architecture for low-cost and compact SATCOM mobile terminal is presented. Based on equal-amplitude aperiodic phased array with fewer active chain numbers, it possesses advantages including lower weight, less cost, and higher power efficiency compared to conventional periodic phased arrays. It is implemented with printed patch antenna so that it guarantees compactness. The elements position and dimensions are jointly designed, with an effective sparse array synthesis strategy that takes actual patch antenna design constraint into consideration, to obtain a maximum array aperture efficiency. Executable and practical approach for variable dimension patch antenna designing, including defect substrate element and small scale array, is introduced and utilized to implement proposed sparse array. Full-wave simulation results demonstrate the advantages of proposed array antenna as well as the effectiveness of corresponding design approach
Learn From Zoom: Decoupled Supervised Contrastive Learning For WCE Image Classification
Accurate lesion classification in Wireless Capsule Endoscopy (WCE) images is
vital for early diagnosis and treatment of gastrointestinal (GI) cancers.
However, this task is confronted with challenges like tiny lesions and
background interference. Additionally, WCE images exhibit higher intra-class
variance and inter-class similarities, adding complexity. To tackle these
challenges, we propose Decoupled Supervised Contrastive Learning for WCE image
classification, learning robust representations from zoomed-in WCE images
generated by Saliency Augmentor. Specifically, We use uniformly down-sampled
WCE images as anchors and WCE images from the same class, especially their
zoomed-in images, as positives. This approach empowers the Feature Extractor to
capture rich representations from various views of the same image, facilitated
by Decoupled Supervised Contrastive Learning. Training a linear Classifier on
these representations within 10 epochs yields an impressive 92.01% overall
accuracy, surpassing the prior state-of-the-art (SOTA) by 0.72% on a blend of
two publicly accessible WCE datasets. Code is available at:
https://github.com/Qiukunpeng/DSCL.Comment: Accepted by ICASSP202
Multi-Modality is All You Need for Transferable Recommender Systems
ID-based Recommender Systems (RecSys), where each item is assigned a unique
identifier and subsequently converted into an embedding vector, have dominated
the designing of RecSys. Though prevalent, such ID-based paradigm is not
suitable for developing transferable RecSys and is also susceptible to the
cold-start issue. In this paper, we unleash the boundaries of the ID-based
paradigm and propose a Pure Multi-Modality based Recommender system (PMMRec),
which relies solely on the multi-modal contents of the items (e.g., texts and
images) and learns transition patterns general enough to transfer across
domains and platforms. Specifically, we design a plug-and-play framework
architecture consisting of multi-modal item encoders, a fusion module, and a
user encoder. To align the cross-modal item representations, we propose a novel
next-item enhanced cross-modal contrastive learning objective, which is
equipped with both inter- and intra-modality negative samples and explicitly
incorporates the transition patterns of user behaviors into the item encoders.
To ensure the robustness of user representations, we propose a novel noised
item detection objective and a robustness-aware contrastive learning objective,
which work together to denoise user sequences in a self-supervised manner.
PMMRec is designed to be loosely coupled, so after being pre-trained on the
source data, each component can be transferred alone, or in conjunction with
other components, allowing PMMRec to achieve versatility under both
multi-modality and single-modality transfer learning settings. Extensive
experiments on 4 sources and 10 target datasets demonstrate that PMMRec
surpasses the state-of-the-art recommenders in both recommendation performance
and transferability. Our code and dataset is available at:
https://github.com/ICDE24/PMMRec.Comment: ICDE'24 Accepte
UPOCR: Towards Unified Pixel-Level OCR Interface
In recent years, the optical character recognition (OCR) field has been
proliferating with plentiful cutting-edge approaches for a wide spectrum of
tasks. However, these approaches are task-specifically designed with divergent
paradigms, architectures, and training strategies, which significantly
increases the complexity of research and maintenance and hinders the fast
deployment in applications. To this end, we propose UPOCR, a
simple-yet-effective generalist model for Unified Pixel-level OCR interface.
Specifically, the UPOCR unifies the paradigm of diverse OCR tasks as
image-to-image transformation and the architecture as a vision Transformer
(ViT)-based encoder-decoder. Learnable task prompts are introduced to push the
general feature representations extracted by the encoder toward task-specific
spaces, endowing the decoder with task awareness. Moreover, the model training
is uniformly aimed at minimizing the discrepancy between the generated and
ground-truth images regardless of the inhomogeneity among tasks. Experiments
are conducted on three pixel-level OCR tasks including text removal, text
segmentation, and tampered text detection. Without bells and whistles, the
experimental results showcase that the proposed method can simultaneously
achieve state-of-the-art performance on three tasks with a unified single
model, which provides valuable strategies and insights for future research on
generalist OCR models. Code will be publicly available
Design And Hydraulic Performance Of A Novel Hydraulic Ram Pump
The automatic hydraulic ram pump (hydram) is a unique device that utilizes energy from a falling quantity of water as the driving power to pump some of the water to a head much higher than the source. The hydraulic ram is structurally simple, consisting of only two moving parts: the waste valve and the delivery (check) valve. There is also an air chamber with an air or snifter valve. With a continuous flow of water, the hydram will operate automatically and continuously with no other external energy. Hydrams are suitable for small-scale water supply schemes supplying farm- houses and isolated settlements as well as in rural situations in developing countries. The authors develop a novel hydram that contains the three innovations. A new structure and shape of hydram is designed to greatly reduce its size and weight, but has the similar hydraulic performance to the conventional hydrams. Based on hard metal seal, the elastic seal is added for the waste valve and the delivery valve, respectively. The hard metal seal primarily bears the impact of the moving valve disc while the elastic seal is responsible for sealing and reducing noise from the impact of the moving valve disc against the hard metal seal. A device, consisting of a valve and a short pipe that connects the air chamber to the lifting pipe, is added to automatically adjust the gas volume upper the air chamber, so as to keep the hydram operating in a state of high efficiency. Finally, the hydraulic performance of the novel hydram is measured by the model tests
Effect of Mild Heating Assisted Alkaline pH Shift Treatment on the Structural and Functional Properties of Porcine Liver Protein
In this study, a combined method of physical and chemical modification was used to improve the functional characteristics of porcine liver protein (PLP). PLP was modified by mild heating assisted alkaline pH shift treatment. The hydration properties, surface properties, particle size distribution, denaturation degree and molecular structure of modified PLP were measured. The results showed that heat treatment combined with a large shift in pH toward the alkaline side significantly increased the solubility and emulsifying activity of PLP, reduced the particle size while resulting in uniform size distribution, increased the absolute value of zeta potential, and decreased the free sulfhydryl content, changed the primary, secondary and tertiary structures, and increased the surface hydrophobicity. The combined treatment was superior to either treatment alone. In terms of improvements in the hydration and surface properties of PLP, heating at 50 ℃ combined with pH shift toward pH 11 was the best modification condition for PLP
Climate change and its influence on the Karst groundwater recharge in the Jinci Spring Region, Northern China
Due to climate change and human activities over the last fifty years, the spring flow
volume of karst groundwater has sharply diminished in China. Climate change is one of the critical
factors that initiates a series of karst hydrogeologic and water ecological environmental problems,
because the precipitation shows a decreasing trend while the temperature shows an increasing trend.
The Jinci Spring is one of the largest, most famous springs in northern China. This study employed
data from the Taiyuan Meteorological Station and ten precipitation stations in and around the Jinci
Spring region as well as the runoff data gathered from two hydrological monitoring stations during
1960-2012. The sliding average method and the Mann-Kendall test were used to analyze the variation
tendency of precipitation, temperature, and land evaporation in this area. Finally, the following
were calculated: the varying pattern of the karst groundwater recharge amount and the response
of the recharge amount to precipitation, land evaporation, and river runoff by quantitative analysis.
The results indicated that the precipitation and land evaporation amount decreased at first and then
subsequently increased. Likewise, the variation trend of the karst groundwater recharge amount
in the spring region was roughly consistent with the precipitation variation pattern. In contrast,
the temperature displayed an increasing trend. The climate change resulted in a reduction of the
karst groundwater recharge amount, and it had the greatest influence in the 1990s, which caused the
karst groundwater recharge amount to decrease 26.75 mm as compared to that of the 1960s (about
39.68% lower than that of the 1960s). The Jinci Spring had zero flow during this period. The reduction
in precipitation was one of main factors that caused the cutoff of the Jinci Spring.IS
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