110 research outputs found
MDP-Based Scheduling Design for Mobile-Edge Computing Systems with Random User Arrival
In this paper, we investigate the scheduling design of a mobile-edge
computing (MEC) system, where the random arrival of mobile devices with
computation tasks in both spatial and temporal domains is considered. The
binary computation offloading model is adopted. Every task is indivisible and
can be computed at either the mobile device or the MEC server. We formulate the
optimization of task offloading decision, uplink transmission device selection
and power allocation in all the frames as an infinite-horizon Markov decision
process (MDP). Due to the uncertainty in device number and location,
conventional approximate MDP approaches to addressing the curse of
dimensionality cannot be applied. A novel low-complexity sub-optimal solution
framework is then proposed. We first introduce a baseline scheduling policy,
whose value function can be derived analytically. Then, one-step policy
iteration is adopted to obtain a sub-optimal scheduling policy whose
performance can be bounded analytically. Simulation results show that the gain
of the sub-optimal policy over various benchmarks is significant.Comment: 6 pages, 3 figures; accepted by Globecom 2019; title changed to
better describe the work, introduction condensed, typos correcte
Visual cryptography with cheating shares
Visual cryptography is a technique that applies the human visual system to decode
encrypted information, such as text, image and number, without any sophisticated
devices and computing capabilities. Therefore, compared with the traditional cryptography,
it is apparent that it saves a large amount of time and money on devices and
computations. Also, visual cryptography provides the convenience for humans to carry
out decryption with a portal card which is significant to the business application. In
the past decade, visual cryptography has been thoroughly researched not only on its
contrast and subpixel expansion, but also on its applications.
The main contribution of this thesis is the security of visual cryptography related
to the dishonest shareholders. This is the first known work concerning this variety
of potentially secure problem. In the previous papers, the shareholders are inherently
honest. However, in the real world, it is impossible to guarantee that every shareholder
would be honest forever(e.g., because of the interest of business or military, some
shareholders might change to be the traitors). Therefore, a new method based on
visual authentication[16] is proposed and the improvement is also made. In this thesis,
we also review the previous papers on different fields of the visual cryptography
GoSum: Extractive Summarization of Long Documents by Reinforcement Learning and Graph Organized discourse state
Extracting summaries from long documents can be regarded as sentence
classification using the structural information of the documents. How to use
such structural information to summarize a document is challenging. In this
paper, we propose GoSum, a novel graph and reinforcement learning based
extractive model for long-paper summarization. In particular, GoSum encodes
sentence states in reinforcement learning by building a heterogeneous graph for
each input document at different discourse levels. An edge in the graph
reflects the discourse hierarchy of a document for restraining the semantic
drifts across section boundaries. We evaluate GoSum on two datasets of
scientific articles summarization: PubMed and arXiv. The experimental results
have demonstrated that GoSum achieve state-of-the-art results compared with
strong baselines of both extractive and abstractive models. The ablation
studies further validate that the performance of our GoSum benefits from the
use of discourse information
Efficient Spatial Reasoning for Human Pose Estimation
Human pose estimation from single images has made significant progress in the past but still faces fundamental challenges from the occlusion and overlapping of joints in many cases. This is partly due to the limitation of the traditional paradigm for this problem, which attempts to locate human body joints solely and as a result can fail to resolve the spatial connections among joints that are critical for the identification of the whole pose. To overcome this shortcoming, we propose to explicitly incorporate spatial reasoning into pose estimation by formulating it as a structured graph learning problem, in which each image pixel is a candidate graph node with every two nodes connected via an edge that captures their affinity. The advantage of this representation is that it allows us to learn feature embeddings for both the nodes and edges, thereby providing a sufficient capacity to delineate correct human body joints and their connecting bones. To facilitate efficient learning and inference, we exploit self-attention transformer architectures that fuse node and edge learning pathways, which can save parameter numbers and permit fast computation. Experiments on the popular MS-COCO Human pose estimation benchmark show that our method outperforms representative methods
Biomedical Entity Recognition by Detection and Matching
Biomedical named entity recognition (BNER) serves as the foundation for
numerous biomedical text mining tasks. Unlike general NER, BNER require a
comprehensive grasp of the domain, and incorporating external knowledge beyond
training data poses a significant challenge. In this study, we propose a novel
BNER framework called DMNER. By leveraging existing entity representation
models SAPBERT, we tackle BNER as a two-step process: entity boundary detection
and biomedical entity matching. DMNER exhibits applicability across multiple
NER scenarios: 1) In supervised NER, we observe that DMNER effectively
rectifies the output of baseline NER models, thereby further enhancing
performance. 2) In distantly supervised NER, combining MRC and AutoNER as span
boundary detectors enables DMNER to achieve satisfactory results. 3) For
training NER by merging multiple datasets, we adopt a framework similar to
DS-NER but additionally leverage ChatGPT to obtain high-quality phrases in the
training. Through extensive experiments conducted on 10 benchmark datasets, we
demonstrate the versatility and effectiveness of DMNER.Comment: 9 pages content, 2 pages appendi
Multiconstrained gene clustering based on generalized projections
<p>Abstract</p> <p>Background</p> <p>Gene clustering for annotating gene functions is one of the fundamental issues in bioinformatics. The best clustering solution is often regularized by multiple constraints such as gene expressions, Gene Ontology (GO) annotations and gene network structures. How to integrate multiple pieces of constraints for an optimal clustering solution still remains an unsolved problem.</p> <p>Results</p> <p>We propose a novel multiconstrained gene clustering (MGC) method within the generalized projection onto convex sets (POCS) framework used widely in image reconstruction. Each constraint is formulated as a corresponding set. The generalized projector iteratively projects the clustering solution onto these sets in order to find a consistent solution included in the intersection set that satisfies all constraints. Compared with previous MGC methods, POCS can integrate multiple constraints from different nature without distorting the original constraints. To evaluate the clustering solution, we also propose a new performance measure referred to as Gene Log Likelihood (GLL) that considers genes having more than one function and hence in more than one cluster. Comparative experimental results show that our POCS-based gene clustering method outperforms current state-of-the-art MGC methods.</p> <p>Conclusions</p> <p>The POCS-based MGC method can successfully combine multiple constraints from different nature for gene clustering. Also, the proposed GLL is an effective performance measure for the soft clustering solutions.</p
Prediction of overall survival for patients with metastatic castration-resistant prostate cancer : development of a prognostic model through a crowdsourced challenge with open clinical trial data
Background Improvements to prognostic models in metastatic castration-resistant prostate cancer have the potential to augment clinical trial design and guide treatment strategies. In partnership with Project Data Sphere, a not-for-profit initiative allowing data from cancer clinical trials to be shared broadly with researchers, we designed an open-data, crowdsourced, DREAM (Dialogue for Reverse Engineering Assessments and Methods) challenge to not only identify a better prognostic model for prediction of survival in patients with metastatic castration-resistant prostate cancer but also engage a community of international data scientists to study this disease. Methods Data from the comparator arms of four phase 3 clinical trials in first-line metastatic castration-resistant prostate cancer were obtained from Project Data Sphere, comprising 476 patients treated with docetaxel and prednisone from the ASCENT2 trial, 526 patients treated with docetaxel, prednisone, and placebo in the MAINSAIL trial, 598 patients treated with docetaxel, prednisone or prednisolone, and placebo in the VENICE trial, and 470 patients treated with docetaxel and placebo in the ENTHUSE 33 trial. Datasets consisting of more than 150 clinical variables were curated centrally, including demographics, laboratory values, medical history, lesion sites, and previous treatments. Data from ASCENT2, MAINSAIL, and VENICE were released publicly to be used as training data to predict the outcome of interest-namely, overall survival. Clinical data were also released for ENTHUSE 33, but data for outcome variables (overall survival and event status) were hidden from the challenge participants so that ENTHUSE 33 could be used for independent validation. Methods were evaluated using the integrated time-dependent area under the curve (iAUC). The reference model, based on eight clinical variables and a penalised Cox proportional-hazards model, was used to compare method performance. Further validation was done using data from a fifth trial-ENTHUSE M1-in which 266 patients with metastatic castration-resistant prostate cancer were treated with placebo alone. Findings 50 independent methods were developed to predict overall survival and were evaluated through the DREAM challenge. The top performer was based on an ensemble of penalised Cox regression models (ePCR), which uniquely identified predictive interaction effects with immune biomarkers and markers of hepatic and renal function. Overall, ePCR outperformed all other methods (iAUC 0.791; Bayes factor >5) and surpassed the reference model (iAUC 0.743; Bayes factor >20). Both the ePCR model and reference models stratified patients in the ENTHUSE 33 trial into high-risk and low-risk groups with significantly different overall survival (ePCR: hazard ratio 3.32, 95% CI 2.39-4.62, p Interpretation Novel prognostic factors were delineated, and the assessment of 50 methods developed by independent international teams establishes a benchmark for development of methods in the future. The results of this effort show that data-sharing, when combined with a crowdsourced challenge, is a robust and powerful framework to develop new prognostic models in advanced prostate cancer.Peer reviewe
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