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结合用户主观偏好与项目属性扩充的推荐算法 被引量:2
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作者 钟耀亿 丁晓剑 杨帆 《计算机系统应用》 2021年第9期192-199,共8页
协同过滤算法是推荐系统中使用广泛的一种算法,然而传统协同过滤算法仅利用评分信息,实际场景下会面临相似度计算准确率低,推荐个性化程度不高的缺陷,难以满足用户的需求.针对协同过滤算法的不足,结合用户主观偏好与项目属性扩充提出一... 协同过滤算法是推荐系统中使用广泛的一种算法,然而传统协同过滤算法仅利用评分信息,实际场景下会面临相似度计算准确率低,推荐个性化程度不高的缺陷,难以满足用户的需求.针对协同过滤算法的不足,结合用户主观偏好与项目属性扩充提出一种改进算法,首先在项目相似度计算上做了两个改进:引入标签相关度,依据项目标签相关度来研究项目之间的相似度,并根据项目历史评分用户的特征构造项目的扩充属性,可用于从项目受众类型的角度衡量项目相似度;其次考虑到用户存在主观偏好的情况,使用支持向量机为每个用户训练标签偏好预测模型,可用于项目预测评分的修正,提高推荐的个性化程度和准确度.基于MovieLens数据集的实验结果表明,所提算法能更准确地计算项目间的相似度,且能根据用户的个性化偏好得出更精确的预测评分. 展开更多
关键词 协同过滤 相似度 属性扩充 个性化偏好 支持向量机
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基于Web的实例扩展与属性值扩充方法 被引量:1
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作者 李贵 陈韶刚 +3 位作者 韩子扬 李征宇 孙平 孙焕良 《计算机科学》 CSCD 北大核心 2014年第B11期411-418,共8页
实例扩展与属性值扩充是Web抽取与集成领域中的一个重要研究课题,将Web数据列表和实例建模成二分图,根据扩展实例的质量分数,对扩展集合进行迭代更新直到扩展集合的质量分数最大,且扩展集合不再更新来实现实例的扩展。同时,为了完善扩... 实例扩展与属性值扩充是Web抽取与集成领域中的一个重要研究课题,将Web数据列表和实例建模成二分图,根据扩展实例的质量分数,对扩展集合进行迭代更新直到扩展集合的质量分数最大,且扩展集合不再更新来实现实例的扩展。同时,为了完善扩展实例的属性信息,对结构化数值属性或离散属性进行抽取,提出了基于整数线性规划的属性值扩充方法。实验表明,与以前的方法相比,本方法能更好地处理含有噪声数据的Web网页,并提高了抽取的准确率和召回率。 展开更多
关键词 实例扩展 属性扩充 整数线性规划
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Prophylactic stenting for esophageal stricture prevention after endoscopic submucosal dissection 被引量:18
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作者 Ke-Da Shi Feng Ji 《World Journal of Gastroenterology》 SCIE CAS 2017年第6期931-934,共4页
Endoscopic submucosal dissection (ESD) of superficial esophageal cancer has been increasingly used as an alternative to surgery because it is minimally invasiveand has a high rate of en bloc resection. However, a high... Endoscopic submucosal dissection (ESD) of superficial esophageal cancer has been increasingly used as an alternative to surgery because it is minimally invasiveand has a high rate of en bloc resection. However, a high rate of esophageal stricture is observed after ESD for large lesions, which can dramatically decrease the patient's quality of life. Stricture prevention is necessary to allow for endoscopic therapy to expand. We, herein, review the most recent evidence and discuss the role of the metallic self-expandable stent and the biodegradable stent in esophageal stricture prevention. Limited studies suggested that prophylactic stenting could reduce the stricture rate without increasing the number of complications. In addition, the number of bougie dilation procedures was significantly lower with stent placement. Esophageal stenting is a promising option for post-ESD stricture prevention. However, current evidence is too preliminary to formulate practice standards. Future studies are needed to further validate the efficacy and safety of prophylactic stenting and determine the best strategy for stricture prevention. Stent migration is the most common complication. A new stent that has advantages of a low migration rate and minimal tissue reaction will need to be developed. Therefore, randomized controlled trials with long-term follow-up periods are required before prophylactic stenting could be considered a valid option to prevent post-ESD stricture. 展开更多
关键词 可被细菌破坏的 stent 苛评预防 食道的苛评 属性的自我可扩充 stent 内视镜的 submucosal 解剖
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Predictive factors for the failure of endoscopic stent-instent self-expandable metallic stent placement to treat malignant hilar biliary obstruction 被引量:3
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作者 Mitsuru Sugimoto Tadayuki Takagi +10 位作者 Rei Suzuki Naoki Konno Hiroyuki Asama Ko Watanabe Jun Nakamura Hitomi Kikuchi Yuichi Waragai Mika Takasumi Yuki Sato Takuto Hikichi Hiromasa Ohira 《World Journal of Gastroenterology》 SCIE CAS 2017年第34期6273-6280,共8页
AIM To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents(SEMSs). METHODS This study evaluated 65 patients with an unresectable malignant hilar biliary obstruct... AIM To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents(SEMSs). METHODS This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography(ERCP) procedures between the two groups.RESULTS The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices(ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve(sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. CONCLUSION A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement. 展开更多
关键词 内视镜的 stent-in-stent 自我可扩充的金属性 stent 放置 预兆的因素 内视镜后退 cholangiopancreatography 恶意的 hilar 胆汁的阻塞 自我可扩充的金属性 stent
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Ischemic or toxic injury: A challenging diagnosis and treatment of drug-induced stenosis of the sigmoid colon 被引量:2
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作者 Zong-Ming Zhang Xiang-Chun Lin +25 位作者 Li Ma An-Qin Jin Fang-Cai Lin Zhuo Liu Li-Min Liu Chong Zhang Na Zhang Li-Juan Huo Xue-Liang Jiang Feng Kang Hong-Jun Qin Qiu-Yang Li Hong-Wei Yu Hai Deng Ming-Wen Zhu Zi-Xu Liu Bai-Jiang Wan Hai-Yan Yang Jia-Hong Liao Xu Luo You-Wei Li Wen-Ping Wei Meng-Meng Song Yue Zhao Xue-Ying Shi Zhao-Hui Lu 《World Journal of Gastroenterology》 SCIE CAS 2017年第21期3934-3944,共11页
A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagno... A 48-year-old woman was admitted with 15-mo history of abdominal pain, diarrhea and hematochezia, and 5-mo history of defecation difficulty. She had been successively admitted to nine hospitals, with an initial diagnosis of inflammatory bowel disease with stenotic sigmoid colon. Findings from computed tomography virtual colonoscopy, radiography with meglumine diatrizoate, endoscopic balloon dilatation, metallic stent implantation and later overall colonoscopy, coupled with the newfound knowledge of compound Qingdai pill-taking, led to a subsequent diagnosis of ischemic or toxic bowel disease with sigmoid colon stenosis. The patient was successfully treated by laparoscopic sigmoid colectomy, and postoperative pathological examination revealed ischemic or toxic injury of the sigmoid colon, providing a final diagnosis of druginduced sigmoid colon stenosis. This case highlights that adequate awareness of drug-induced colon stenosis has a decisive role in avoiding misdiagnosis and mistreatment. The diagnostic and therapeutic experiences learnt from this case suggest that endoscopic balloon expansion and colonic metallic stent implantation as bridge treatments were demonstrated as crucial for the differential diagnosis of benign colonic stenosis. Skillful surgical technique and appropriate perioperative management helped to ensure the safety of our patient in subsequent surgery after long-term use of glucocorticoids. 展开更多
关键词 良性的结肠的狭窄 加重 Qingdai 药片 自我可扩充的记忆金属性 stent
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Safety and efficacy of self-expandable metallic stents in malignant small bowel obstructions 被引量:1
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作者 Akiyoshi Tsuboi Toshio Kuwai +7 位作者 Tomoyuki Nishimura Sumio Iio Takeshi Mori Hiroki Imagawa Toshiki Yamaguchi Atsushi Yamaguchi Hirotaka Kouno Hiroshi Kohno 《World Journal of Gastroenterology》 SCIE CAS 2016年第40期9022-9027,共6页
In this report, we present 3 cases of malignant small bowel obstruction, treated with palliative care using endoscopic self-expandable metallic stent(SEMS) placement, with the aim to identify the safety and efficacy o... In this report, we present 3 cases of malignant small bowel obstruction, treated with palliative care using endoscopic self-expandable metallic stent(SEMS) placement, with the aim to identify the safety and efficacy of this procedure. Baseline patient characteristics, procedure methods, procedure time, technical and clinical success rates, complications, and patient outcomes were obtained. All 3 patients had pancreatic cancer with small bowel strictures. One patient received the SEMS using colonoscopy, while the other 2 patients received SEMS placement via double balloon endoscopy using the through-the-overtube technique. The median procedure time was 104 min. The technical and clinical success rates were 100%. Post-treatment, obstructive symptoms in all patients improved, and a low-residue diet could be tolerated. All stents remained within the patients until their deaths. The median overall survival time(stent patency time) was 76 d. SEMS placement is safe and effective as a palliative treatment for malignant small bowel obstruction. 展开更多
关键词 自我可扩充的金属性 stents 恶意的小肠阻塞 内视镜检查法 案例报告 胰腺的癌症
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PB访问ACCESS数据库的问题探讨
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作者 李连桂 《微计算机应用》 1998年第6期376-379,共4页
分析了PB访问1.x和2.0版本的ACCESS数据库时存在的两个问题并揭示了通过ODBC访问ACCESS 2.0版数据库不能正确更新数据的原因。给出了向ACCESS 1.x数据表添加扩充属性的方法和PB正常访问2.0版ACCESS数据库文件的方法,并提出了两者互为补... 分析了PB访问1.x和2.0版本的ACCESS数据库时存在的两个问题并揭示了通过ODBC访问ACCESS 2.0版数据库不能正确更新数据的原因。给出了向ACCESS 1.x数据表添加扩充属性的方法和PB正常访问2.0版ACCESS数据库文件的方法,并提出了两者互为补充的方案。 展开更多
关键词 PB ACCESS 扩充属性 数据更新 数据库
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