610 research outputs found
A Formal Semantic Model of the Semantic Web Service Ontology (WSMO)
Semantic Web Services, one of the most significant research areas within the Semantic Web vision, has attracted increasing attention from both the research community and industry. The Web Service Modelling Ontology (WSMO) has recently been proposed as an enabling framework for the total/partial automation of the tasks (e.g., discovery, selection, composition, mediation, execution, monitoring, etc.) involved in both intra- and inter-enterprise integration of Web Services. To support the standardization and tool support of WSMO, a formal semantics of the language is highly desirable. As there are a few variants of WSMO and it is still under development, the semantics of WSMO needs to be formally defined to facilitate easy reuse and future development. In this paper, we present a formal Object-Z semantics of WSMO. Different aspects of the language have been precisely defined within one unified framework. This model not only provides a formal unambiguous model which can be used to develop tools and facilitate future development, but as demonstrated in this paper, can be used to identify and eliminate errors presented in existing documentation
A Formal Model of Semantic Web Service Ontology (WSMO) Execution
Semantic Web Services have been one of the most significant research areas within the Semantic Web vision, and have been recognized as a promising technology that exhibits huge commercial potential. Current Semantic Web Service research focuses on defining models and languages for the semantic markup of all relevant aspects of services, which are accessible through a Web service interface. The Web Service Modelling Ontology (WSMO) is one of the most significant Semantic Web Service framework proposed to date. To support the standardization and tool support of WSMO, a formal semantics of the language is highly desirable. As there are a few variants of WSMO and it is still under development, the semantics of WSMO needs to be formally defined to facilitate easy reuse and future development. In this paper, we present a formal Object-Z semantics of WSMO. Different aspects of the language have been precisely defined within one unified framework. This model provides a formal unambiguous specification, which can be used to develop tools and facilitate future development
Midlife moderation-quantified healthy diet and 40-year mortality risk from CHD: the prospective National Heart, Lung, and Blood Institute Twin Study
It is unknown whether influences of midlife whole diet on the long-term CHD mortality risk are independent of genetic and common environmental factors or familial predisposition. We addressed this question prospectively using data from the National Heart, Lung, and Blood Institute Twin Study. We included 910 male twins who were middle-aged and had usual diet assessed with nutritionist-administered, cross-checked dietary history interview at baseline (1969-1973). Moderation-quantified healthy diet (MQHD), a dietary pattern, was created to evaluate a whole diet. Primary outcome was time-to-CHD death. Hazard ratios (HR) were estimated using frailty survival model. Known CHD risk factors were controlled. During the follow-up of 40 years through 31 December 2009, 113 CHD deaths, 198 total cardiovascular deaths and 610 all-cause deaths occurred. In the entire cohort, the multivariable-adjusted HR for the overall association (equivalent to a general population association) was 0·76 (95 % CI 0·66, 0·88) per 10-unit increment in the MQHD score for CHD, and the multivariable-adjusted HR for a twin with a MQHD score ten units higher than his co-twin brother was 0·79 (95 % CI 0·64, 0·96, P=0·02) for CHD independent of familial predisposition. Similar results were found for a slightly more food-specified alternative moderation-quantified healthy diet (aMQHD). The between-pair association (reflecting familial influence) was significant for CHD for both MQHD and aMQHD. It is concluded that associations of MQHD and aMQHD with a lower long-term CHD mortality risk are both nutritionally and familially affected, supporting their use for dietary planning to prevent CHD mortality
Electrolysis-based on-chip dispensing system for ESI-MS
We report here an integrated on-chip sample dispensing system for Electrospray Ionization-Mass Spectrometry (ESI-MS) applications. The stand-alone chip includes an electrolysis-based micropump, a passive micro mixer and an ESI nozzle. Operation of the chip doesn't require any external fluidic coupling because the chip is designed to have samples filled, sealed and stored in reservoirs inside the chip before testing. Demonstrated here is a chip with two sample reservoirs and dispensing of the samples is electrically controlled individually. Experimentally, on-chip co-dispensing of two different samples is successfully achieved with a dispensing flow rate about 50 nl/min and a continuous spray for 2 minutes
CAMANet: Class Activation Map Guided Attention Network for Radiology Report Generation
Radiology report generation (RRG) has gained increasing research attention
because of its huge potential to mitigate medical resource shortages and aid
the process of disease decision making by radiologists. Recent advancements in
Radiology Report Generation (RRG) are largely driven by improving models'
capabilities in encoding single-modal feature representations, while few
studies explore explicitly the cross-modal alignment between image regions and
words. Radiologists typically focus first on abnormal image regions before they
compose the corresponding text descriptions, thus cross-modal alignment is of
great importance to learn an abnormality-aware RRG model. Motivated by this, we
propose a Class Activation Map guided Attention Network (CAMANet) which
explicitly promotes cross-modal alignment by employing the aggregated class
activation maps to supervise the cross-modal attention learning, and
simultaneously enriches the discriminative information. Experimental results
demonstrate that CAMANet outperforms previous SOTA methods on two commonly used
RRG benchmarks.Comment: 15 pages, 7 figure
Some Supervision Required: Incorporating Oracle Policies in Reinforcement Learning via Epistemic Uncertainty Metrics
An inherent problem of reinforcement learning is performing exploration of an
environment through random actions, of which a large portion can be
unproductive. Instead, exploration can be improved by initializing the learning
policy with an existing (previously learned or hard-coded) oracle policy,
offline data, or demonstrations. In the case of using an oracle policy, it can
be unclear how best to incorporate the oracle policy's experience into the
learning policy in a way that maximizes learning sample efficiency. In this
paper, we propose a method termed Critic Confidence Guided Exploration (CCGE)
for incorporating such an oracle policy into standard actor-critic
reinforcement learning algorithms. More specifically, CCGE takes in the oracle
policy's actions as suggestions and incorporates this information into the
learning scheme when uncertainty is high, while ignoring it when the
uncertainty is low. CCGE is agnostic to methods of estimating uncertainty, and
we show that it is equally effective with two different techniques.
Empirically, we evaluate the effect of CCGE on various benchmark reinforcement
learning tasks, and show that this idea can lead to improved sample efficiency
and final performance. Furthermore, when evaluated on sparse reward
environments, CCGE is able to perform competitively against adjacent algorithms
that also leverage an oracle policy. Our experiments show that it is possible
to utilize uncertainty as a heuristic to guide exploration using an oracle in
reinforcement learning. We expect that this will inspire more research in this
direction, where various heuristics are used to determine the direction of
guidance provided to learning.Comment: Under review at TML
Photosystem II Peripheral Accessory Chlorophyll Mutants in Chlamydomonas reinhardtii. Biochemical Characterization and Sensitivity to Photo-Inhibition
In addition to the four chlorophylls (Chls) involved in primary charge separation, the photosystem II (PSII) reaction center polypeptides, D1 and D2, coordinate a pair of symmetry-related, peripheral accessory Chls. These Chls are axially coordinated by the D1-H118 and D2-H117 residues and are in close association with the proximal Chl antennae proteins, CP43 and CP47. To gain insight into the function(s) of each of the peripheral Chls, we generated site-specific mutations of the amino acid residues that coordinate these Chls and characterized their energy and electron transfer properties. Our results demonstrate that D1-H118 and D2-H117 mutants differ with respect to: (a) their relative numbers of functional PSII complexes, (b) their relative ability to stabilize charge-separated states, (c) light-harvesting efficiency, and (d) their sensitivity to photo-inhibition. The D2-H117N and D2-H117Q mutants had reduced levels of functional PSII complexes and oxygen evolution capacity as well as reduced light-harvesting efficiencies relative to wild-type cells. In contrast, the D1-H118Q mutant was capable of near wild-type rates of oxygen evolution at saturating light intensities. The D1-H118Q mutant also was substantially more resistant to photo-inhibition than wild type. This reduced sensitivity to photo-inhibition is presumably associated with a reduced light-harvesting efficiency in this mutant. Finally, it is noted that the PSII peripheral accessory Chls have similarities to a to a pair of Chls also present in the PSI reaction center complex
Sentiment Analysis of Animated Online Education Texts Using Long Short-Term Memory Networks in the Context of the Internet of Things
This work aims to introduce Long Short-Term Memory (LSTM) under the Internet of Things (IoT) context to enhance the accuracy and granularity of sentiment analysis in animated online education texts. It employs a multimodal data collection approach and uses IoT technology to gather multimodal textual data from students engaged in animated online education. The data includes students' feedback texts, emotional texts, written texts, and verbal expressions during animated online education. Subsequently, a model named Information Block Bidirectional Long-Short term Memory (IB-BiLSTM) is designed and utilized to construct a sentiment classification model for animated online education texts. Experimental results demonstrate that the model achieves an accuracy of 93.92% and an F1-score of 90.34% for sentiment classification in animated online education texts and the loss function converges to around 0.14.
This model effectively captures the emotional changes and evolution during students' learning process. Thus, the proposed model holds significant potential and practical significance for enhancing animated online education's personalization and emotional engagement. It provides valuable insights and guidance for the intelligent development of the education field
Gene conversion in the rice genome
Background: Gene conversion causes a non-reciprocal transfer of genetic information between similar sequences. Gene conversion can both homogenize genes and recruit point mutations thereby shaping the evolution of multigene families. In the rice genome, the large number of duplicated genes increases opportunities for gene conversion.
Results: To characterize gene conversion in rice, we have defined 626 multigene families in which 377 gene conversions were detected using the GENECONV program. Over 60% of the conversions we detected were between chromosomes. We found that the inter-chromosomal conversions distributed between chromosome 1 and 5, 2 and 6, and 3 and 5 are more frequent than genome average (Z-test, P < 0.05). The frequencies of gene conversion on the same chromosome decreased with the physical distance between gene conversion partners. Ka/Ks analysis indicates that gene conversion is not tightly linked to natural selection in the rice genome. To assess the contribution of segmental duplication on gene conversion statistics, we determined locations of conversion partners with respect to inter-chromosomal segment duplication. The number of conversions associated with segmentation is less than ten percent. Pseudogenes in the rice genome with low similarity to Arabidopsis genes showed greater likelihood for gene conversion than those with high similarity to Arabidopsis genes. Functional annotations suggest that at least 14 multigene families related to disease or bacteria resistance were involved in conversion events.
Conclusion: The evolution of gene families in the rice genome may have been accelerated by conversion with pseudogenes. Our analysis suggests a possible role for gene conversion in the evolution of pathogen-response genes
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