37 research outputs found
Scribble Hides Class: Promoting Scribble-Based Weakly-Supervised Semantic Segmentation with Its Class Label
Scribble-based weakly-supervised semantic segmentation using sparse scribble
supervision is gaining traction as it reduces annotation costs when compared to
fully annotated alternatives. Existing methods primarily generate pseudo-labels
by diffusing labeled pixels to unlabeled ones with local cues for supervision.
However, this diffusion process fails to exploit global semantics and
class-specific cues, which are important for semantic segmentation. In this
study, we propose a class-driven scribble promotion network, which utilizes
both scribble annotations and pseudo-labels informed by image-level classes and
global semantics for supervision. Directly adopting pseudo-labels might
misguide the segmentation model, thus we design a localization rectification
module to correct foreground representations in the feature space. To further
combine the advantages of both supervisions, we also introduce a distance
entropy loss for uncertainty reduction, which adapts per-pixel confidence
weights according to the reliable region determined by the scribble and
pseudo-label's boundary. Experiments on the ScribbleSup dataset with different
qualities of scribble annotations outperform all the previous methods,
demonstrating the superiority and robustness of our method.The code is
available at
https://github.com/Zxl19990529/Class-driven-Scribble-Promotion-Network
Recommended high performance telescope system design for the TianQin project
China is planning to construct a new space-borne gravitational-wave (GW)
observatory, the TianQin project, in which the spaceborne telescope is an
important component in laser interferometry. The telescope is aimed to transmit
laser beams between the spacecrafts for the measurement of the displacements
between proof-masses in long arms. The telescope should have ultra-small
wavefront deviation to minimize noise caused by pointing error, ultra-stable
structure to minimize optical path noise caused by temperature jitter,
ultra-high stray light suppression ability to eliminate background noise. In
this paper, we realize a telescope system design with ultra-stable structure as
well as ultra-low wavefront distortion for the space-based GW detection
mission. The design requirements demand extreme control of high image quality
and extraordinary stray light suppression ability. Based on the primary
aberration theory, the initial structure design of the mentioned four-mirror
optical system is explored. After optimization, the maximum RMS wavefront error
is less than lamda/300 over the full field of view (FOV), which meets the noise
budget on the telescope design. The stray light noise caused by the back
reflection of the telescope is also analyzed. The noise at the position of
optical bench is less than 10-10 of the transmitted power, satisfying the
requirements of space gravitational-wave detection. We believe that our design
can be a good candidate for TianQin project, and can also be a good guide for
the space telescope design in any other similar science project
Static coupling effect of a two-degree-of-freedom direct drive induction motor
Two-degree-of-freedom motors are capable of producing linear, rotary, and helical motion, and thus have widespread applications in special industries. In this study, a new concept- static coupling effect is studied in the two-degree-of-freedom direct-drive induction motor (2DoFDDIM). The proposed approach is based on the image method and the three-dimensional (3D) finite-element method. The image method model is established to analyse its reasons and predict the main effects, which are then verified by the proposed 3D finite-element static coupling model and experiments. The induced voltages and currents are produced in the static part and induced torque or force is obtained, even though the static part is not energised. It is concluded that the static coupling effect increases with the supply frequency and is influenced by the stator winding configuration. Thus, the existence of the static coupling effect is confirmed, which must be taken into account in future optimisation and precise control of the 2DoFDDIM
A Search for Technosignatures Around 31 Sun-like Stars with the Green Bank Telescope at 1.15-1.73 GHz
We conducted a search for technosignatures in April of 2018 and 2019 with the
L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope.
These observations focused on regions surrounding 31 Sun-like stars near the
plane of the Galaxy. We present the results of our search for narrowband
signals in this data set as well as improvements to our data processing
pipeline. Specifically, we applied an improved candidate signal detection
procedure that relies on the topographic prominence of the signal power, which
nearly doubles the signal detection count of some previously analyzed data
sets. We also improved the direction-of-origin filters that remove most radio
frequency interference (RFI) to ensure that they uniquely link signals observed
in separate scans. We performed a preliminary signal injection and recovery
analysis to test the performance of our pipeline. We found that our pipeline
recovers 93% of the injected signals over the usable frequency range of the
receiver and 98% if we exclude regions with dense RFI. In this analysis, 99.73%
of the recovered signals were correctly classified as technosignature
candidates. Our improved data processing pipeline classified over 99.84% of the
~26 million signals detected in our data as RFI. Of the remaining candidates,
4539 were detected outside of known RFI frequency regions. The remaining
candidates were visually inspected and verified to be of anthropogenic nature.
Our search compares favorably to other recent searches in terms of end-to-end
sensitivity, frequency drift rate coverage, and signal detection count per unit
bandwidth per unit integration time.Comment: 20 pages, 8 figures, in press at the Astronomical Journal (submitted
on Sept. 9, 2020; reviews received Nov. 6; re-submitted Nov. 6; accepted Nov.
17
Neuroimaging and Biosample Collection in the Toronto Adolescent and Youth Cohort Study:Rationale, Methods, and Early Data
BACKGROUND:Â The Toronto Adolescent and Youth (TAY) Cohort Study will characterize the neurobiological trajectories of psychosis spectrum symptoms, functioning, and suicidality (i.e., suicidal thoughts and behaviors) in youth seeking mental health care. Here, we present the neuroimaging and biosample component of the protocol. We also present feasibility and quality control metrics for the baseline sample collected thus far.METHODS:Â The current study includes youths (ages 11-24 years) who were referred to child and youth mental health services within a large tertiary care center in Toronto, Ontario, Canada, with target recruitment of 1500 participants. Participants were offered the opportunity to provide any or all of the following: 1) 1-hour magnetic resonance imaging (MRI) scan (electroencephalography if ineligible for or declined MRI), 2) blood sample for genomic and proteomic data (or saliva if blood collection was declined or not feasible) and urine sample, and 3) heart rate recording to assess respiratory sinus arrhythmia.RESULTS:Â Of the first 417 participants who consented to participate between May 4, 2021, and February 2, 2023, 412 agreed to participate in the imaging and biosample protocol. Of these, 334 completed imaging, 341 provided a biosample, 338 completed respiratory sinus arrhythmia, and 316 completed all 3. Following quality control, data usability was high (MRI: T1-weighted 99%, diffusion-weighted imaging 99%, arterial spin labeling 90%, resting-state functional MRI 95%, task functional MRI 90%; electroencephalography: 83%; respiratory sinus arrhythmia: 99%).CONCLUSIONS:Â The high consent rates, good completion rates, and high data usability reported here demonstrate the feasibility of collecting and using brain imaging and biosamples in a large clinical cohort of youths seeking mental health care.</p
Inferring causal molecular networks: empirical assessment through a community-based effort
Inferring molecular networks is a central challenge in computational biology. However, it has remained unclear whether causal, rather than merely correlational, relationships can be effectively inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge that focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results constitute the most comprehensive assessment of causal network inference in a mammalian setting carried out to date and suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess the causal validity of inferred molecular networks
Inferring causal molecular networks: empirical assessment through a community-based effort
It remains unclear whether causal, rather than merely correlational, relationships in molecular networks can be inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge, which focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective, and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess inferred molecular networks in a causal sense