关系抽取作为知识图谱等诸多领域的上游任务,具有广泛应用价值,近年来受到广泛关注。关系抽取模型普遍存在暴露偏差问题,抽取文本普遍存在实体嵌套和实体重叠问题,这些问题严重影响了模型性能。因此,提出了一种基于片段标注的实体关系...关系抽取作为知识图谱等诸多领域的上游任务,具有广泛应用价值,近年来受到广泛关注。关系抽取模型普遍存在暴露偏差问题,抽取文本普遍存在实体嵌套和实体重叠问题,这些问题严重影响了模型性能。因此,提出了一种基于片段标注的实体关系联合抽取模型(span-labeling based model,SLM),主要包括:将实体关系抽取问题转化为片段标注问题;使用滑动窗口和三种映射策略将词元(token)序列进行组合排列重新平铺成片段(span)序列;使用LSTM和多头自注意力机制进行片段深层语义特征提取;设计了实体关系标签,使用多层标注方法进行关系标签分类。在英文数据集NYT、WebNLG上进行实验,相对于基线模型F1值显著提高,验证了模型的有效性,能有效解决上述问题。展开更多
针对玉米育种文本数据中存在重叠三元组、实体表达方式多样等问题,提出一种嵌入词汇信息的BERT-CRF(Bidirectional encoder representations from transformers-conditional random field)玉米育种实体关系联合抽取方法。首先,分析了玉...针对玉米育种文本数据中存在重叠三元组、实体表达方式多样等问题,提出一种嵌入词汇信息的BERT-CRF(Bidirectional encoder representations from transformers-conditional random field)玉米育种实体关系联合抽取方法。首先,分析了玉米育种语料表达特征,采用对实体边界、关系类别和实体位置信息同步标注的策略;其次,构建了嵌入词汇信息的BERT-CRF模型进行训练和预测,自建玉米育种知识词典,通过在BERT中嵌入词汇信息,融合字符特征和词汇特征,增强模型的语义能力,利用CRF模型输出全局最优标签序列,设计了实体关系三元组匹配算法(Entity and relation triple matching algorithm,ERTM),将标签进行匹配和映射来获取三元组;最后,为验证该方法的有效性,在玉米育种数据集上进行实验,结果表明,本文模型精确率、召回率和F1值分别为91.84%、95.84%、93.80%,与现有模型相比性能均有提升。说明该方法能够有效抽取玉米育种领域知识,为构建玉米育种知识图谱及其它下游任务提供数据基础。展开更多
Seven female patients (mean age of 56 years) with advanced hip joint osteoarthritis underwent total hip replacement. Four days before operation they were given oral tetracycline for two days. During operation specimen...Seven female patients (mean age of 56 years) with advanced hip joint osteoarthritis underwent total hip replacement. Four days before operation they were given oral tetracycline for two days. During operation specimens were taken from the white articular cartilage, the yellowish articular cartilage and the ivory bone together with their subchondral bone tissues. The undecalcified specimens were cut into 10 μm sections and observed under the fluorescence microscope. In all the specimens the following findings could be observed. 1. The osteoarthritic articular cartilage became thinner, with uneven surface and fissures. 2. The superficial and deep surfaces and the central part of the subchondral bone plate showed bright golden yellow fluorescence. It reflected extensive new bone formation. 3. The subchondral bone trabeculae also revealed bright golden yellow fluorescence on their peripheral borders, so trabeculae turned thicker obviously. 4. The marrow tissues between the bone trabeculae exhibited particulate or spherical bright golden yellow fluorescence, reflecting new bone formation in the marrow. The particulate and spherical bright golden yellow fluorescent materials might aggregate, enlarge and merge into large piece of new bone and they also fused with the neighbouring bone trabeculae. The aforementioned changes in the structure of the subchondral bone tissues increased greatly the mass in the osteoarthritic femoral head.展开更多
文摘关系抽取作为知识图谱等诸多领域的上游任务,具有广泛应用价值,近年来受到广泛关注。关系抽取模型普遍存在暴露偏差问题,抽取文本普遍存在实体嵌套和实体重叠问题,这些问题严重影响了模型性能。因此,提出了一种基于片段标注的实体关系联合抽取模型(span-labeling based model,SLM),主要包括:将实体关系抽取问题转化为片段标注问题;使用滑动窗口和三种映射策略将词元(token)序列进行组合排列重新平铺成片段(span)序列;使用LSTM和多头自注意力机制进行片段深层语义特征提取;设计了实体关系标签,使用多层标注方法进行关系标签分类。在英文数据集NYT、WebNLG上进行实验,相对于基线模型F1值显著提高,验证了模型的有效性,能有效解决上述问题。
文摘针对玉米育种文本数据中存在重叠三元组、实体表达方式多样等问题,提出一种嵌入词汇信息的BERT-CRF(Bidirectional encoder representations from transformers-conditional random field)玉米育种实体关系联合抽取方法。首先,分析了玉米育种语料表达特征,采用对实体边界、关系类别和实体位置信息同步标注的策略;其次,构建了嵌入词汇信息的BERT-CRF模型进行训练和预测,自建玉米育种知识词典,通过在BERT中嵌入词汇信息,融合字符特征和词汇特征,增强模型的语义能力,利用CRF模型输出全局最优标签序列,设计了实体关系三元组匹配算法(Entity and relation triple matching algorithm,ERTM),将标签进行匹配和映射来获取三元组;最后,为验证该方法的有效性,在玉米育种数据集上进行实验,结果表明,本文模型精确率、召回率和F1值分别为91.84%、95.84%、93.80%,与现有模型相比性能均有提升。说明该方法能够有效抽取玉米育种领域知识,为构建玉米育种知识图谱及其它下游任务提供数据基础。
文摘Seven female patients (mean age of 56 years) with advanced hip joint osteoarthritis underwent total hip replacement. Four days before operation they were given oral tetracycline for two days. During operation specimens were taken from the white articular cartilage, the yellowish articular cartilage and the ivory bone together with their subchondral bone tissues. The undecalcified specimens were cut into 10 μm sections and observed under the fluorescence microscope. In all the specimens the following findings could be observed. 1. The osteoarthritic articular cartilage became thinner, with uneven surface and fissures. 2. The superficial and deep surfaces and the central part of the subchondral bone plate showed bright golden yellow fluorescence. It reflected extensive new bone formation. 3. The subchondral bone trabeculae also revealed bright golden yellow fluorescence on their peripheral borders, so trabeculae turned thicker obviously. 4. The marrow tissues between the bone trabeculae exhibited particulate or spherical bright golden yellow fluorescence, reflecting new bone formation in the marrow. The particulate and spherical bright golden yellow fluorescent materials might aggregate, enlarge and merge into large piece of new bone and they also fused with the neighbouring bone trabeculae. The aforementioned changes in the structure of the subchondral bone tissues increased greatly the mass in the osteoarthritic femoral head.
