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基于减治的点与凸多边形位置关系判定算法
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作者 张浩 沈华 谌刚 《湖北工业大学学报》 2022年第5期33-37,共5页
人们利用移动设备享用的很多位置服务涉及点与凸多边形位置判定问题。移动设备资源受限的客观条件使得设计轻量级算法解决该问题成为当务之急。寻找一种轻量级的判定算法是必要的,减少与点进行操作的边的条数成为一种可行思路。因此,基... 人们利用移动设备享用的很多位置服务涉及点与凸多边形位置判定问题。移动设备资源受限的客观条件使得设计轻量级算法解决该问题成为当务之急。寻找一种轻量级的判定算法是必要的,减少与点进行操作的边的条数成为一种可行思路。因此,基于减治思想提出了一种轻量级点与凸多边形位置关系判定算法。算法包括三个模块:区域划分、点的区域判断和点与凸多边形的位置关系判断。算法通过将点与凸多边形的位置关系判断转化为点与凸多边形的部分区域位置关系判断,减少了时间开销。通过将凸多边形的顶点编序并划分为多个子区域作为算法的预处理部分,算法的时间开销可以达到O(log√n)。本算法可以适用在移动设备资源受限的场景下快速进行点与凸多边形的位置关系判断。 展开更多
关键词 减治法 凸多边形 区域判断 位置关系判定算法
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改进的最小顶点覆盖问题的贪婪算法 被引量:1
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作者 张楠 张升 《内蒙古师范大学学报(自然科学汉文版)》 CAS 北大核心 2012年第2期206-210,共5页
通过分析竞争决策算法、混合贪婪算法和快速降阶算法,在顶点的度及贪心算法的基础上,对顶点添加访问标记符号,并在减治法的概念下设计了最小顶点覆盖问题的一种较为中和性的贪婪算法.该算法消除了邻接度数的概念,直接运用顶点度数来完... 通过分析竞争决策算法、混合贪婪算法和快速降阶算法,在顶点的度及贪心算法的基础上,对顶点添加访问标记符号,并在减治法的概念下设计了最小顶点覆盖问题的一种较为中和性的贪婪算法.该算法消除了邻接度数的概念,直接运用顶点度数来完成算法的实现,从而降低了算法的时间复杂度,且更易于编程.该算法在最坏情况下的时间复杂度为O(|V|2). 展开更多
关键词 最小顶点覆盖问题 贪婪算法 顶点的度 访问标记 减治法
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Multilevel cervical spondylotic myelopathy treated by anterior cervical decompression in subsection and autograft fusion 被引量:4
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作者 赵建华 刘鹏 李起鸿 《Journal of Medical Colleges of PLA(China)》 CAS 2007年第4期209-215,共7页
Objective:To investigate a novel surgical method for multilevel cervical spondylotic myelopathy (CSM). Methods: Totally 21 patients with multilevel CSM undergoing a novel surgical procedure from April 2001 to Janu... Objective:To investigate a novel surgical method for multilevel cervical spondylotic myelopathy (CSM). Methods: Totally 21 patients with multilevel CSM undergoing a novel surgical procedure from April 2001 to January 2004 were analyzed retrospectively. All patients experienced anterior cervical decompression surgery in subsection, autograft fusion and internal fixation. Preoperative, immediate postoperative and follow-up image data, X-rays and semi-quantitative Japanese orthopaedics association (JOA) scores were used to evaluate the restoration of lordosis (Cobb's angle), intervertebral heights, the stability of the cervical spine and the improvement of neurological impairment. Results: Preoperative symptoms were markedly alleviated or disappeared in most of the patients. According to the JOA scores, the ratio of improvement in neurological function was 72. 2%, including excellent in 9 cases (42.9%), good in 7 cases (33.3%), fair in 3 cases (14.3%) and poor in 2 cases (9.5%). Immediate postoperative X-rays showed obvious improvements in lordosis and in the intervertebral height of the cervical spine (P〈0. 01). There is no evidence of instrument failure during the mean follow-up period of 14. 2 months (9-24 months, P〉0. 01). Conclusion:Anterior cervical decompression in subsection, autograft fusion and internal fixation is a rational effective method for the surgical treatment of multilevel CSM. 展开更多
关键词 cervical spondylotic myelopathy MULTILEVEL anterior decompression FUSION internal fixation
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Treatment of hypogonadotropic male hypogonadism: Case-based scenarios 被引量:4
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作者 Lindsey E Crosnoe-Shipley Osama O Elkelany +1 位作者 Cyrus D Rahnema Edward D Kim 《World Journal of Nephrology》 2015年第2期245-253,共9页
The aim of this study is to review four case-based scenarios regarding the treatment of symptomatic hypogonadism in men. The article is designed as a review of published literature. We conducted a PubMed literature se... The aim of this study is to review four case-based scenarios regarding the treatment of symptomatic hypogonadism in men. The article is designed as a review of published literature. We conducted a PubMed literature search for the time period of 1989-2014, concentrating on 26 studies investigating the effcacy of various therapeutic options on semen analysis, pregnancy outcomes, time to recovery of spermatogenesis, as well as serum and intratesticular testosterone levels. Our results demonstrated thatexogenous testosterone suppresses intratesticular testosterone production, which is an absolute prerequisite for normal spermatogenesis. Cessation of exogenous testosterone should be recommended for men desiring to maintain their fertility. Therapies that protect the testis involve human chorionic gonadotropin (hCG) therapy or selective estrogen receptor modulators (SERMs), but may also include low dose hCG with exogenous testosterone. Off-label use of SERMs, such as clomiphene citrate, are effective for maintaining testosterone production long-term and offer the convenience of representing a safe, oral therapy. At present, routine use of aromatase inhibitors is not recommended based on a lack of long-term data. We concluded that exogenous testosterone supplementation decreases sperm production. It was determined that clomiphene citrate is a safe and effective therapy for men who desire to maintain fertility. Although less frequently used in the general population, hCG therapy with or without testosterone supplementation represents an alternative treatment. 展开更多
关键词 HYPOGONADISM Selective estrogen receptor modulator Male fertility CLOMIPHENE Human chorionic gonadotropin
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