Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 wo...Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 workflow in such a network. All the sites in the network performed the annual reference dosimetry in water according to TG-51. These data were used to cross-calibrate the same ion chambers in plastic phantoms for monthly QA output measurements. An energy-specific dimensionless beam quality cross-calibration factor, <img src="Edit_6bfb9907-c034-4197-97a7-e8337a7fc21a.png" width="20" height="19" alt="" />, was derived to monitor the process across multiple sites. The SPC analysis was then performed to obtain the mean, <img src="Edit_c630a2dd-f714-4042-a46e-da0ca863cb41.png" width="30" height="20" alt="" /> , standard deviation, <span style="font-size:6.5pt;font-family:;" "=""><span style="white-space:normal;"><span style="font-size:6.5pt;font-family:"">σ</span><span style="white-space:nowrap;"><sub><i>k</i></sub></span></span></span>, the Upper Control Limit (UCL) and Lower Control Limit (LCL) in each beam. This process was first applied to 15 years of historical data at the main campus to assess the effectiveness of the process. A two-year prospective study including all 30 linear accelerators spread over the main campus and seven satellites in the network followed. The ranges of the control limits (±3σ) were found to be in the range of 1.7% - 2.6% and 3.3% - 4.2% for the main campus and the satellite sites respectively. The wider range in the satellite sites was attributed to variations in the workflow. Standardization of workflow was also found to be effective in narrowing the control limits. The SPC is effective in identifying variations in the workflow and was shown to be an effective tool in managing large network reference dosimetry.展开更多
A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project r...A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project risks. A model for optimizing software risk control is given, a discrete optimization algorithm based on dynamic programruing is proposed and an example of using above method to solve a problem is also included in this paper. By improving the old passive post-project control into an active effective preaction, this new method can greatly promote the possibility of success of software projects.展开更多
为改善起重吊装碰撞风险预警反应时间短、过度预警等问题,开展基于改进统计过程控制(Improved Statistical Process Control,ISPC)的起重吊装防碰撞智能预警研究。建立ISPC模型,选择吊物与障碍物的距离为控制指标,设置中心线等生成控制...为改善起重吊装碰撞风险预警反应时间短、过度预警等问题,开展基于改进统计过程控制(Improved Statistical Process Control,ISPC)的起重吊装防碰撞智能预警研究。建立ISPC模型,选择吊物与障碍物的距离为控制指标,设置中心线等生成控制图,确定预警规则;利用激光雷达获取障碍物点云,经坐标变换、滤波、聚类等处理,监测吊物与障碍物的距离;并设计塔吊吊装的模拟场景,测试ISPC模型的应用效果。结果表明:ISPC模型在两次试验下均及时发现吊物接近障碍物的异常状态,能够触发四类规则并实时预警。ISPC模型在起重吊装潜在碰撞风险的智能预警上提供理论和实践应用价值。展开更多
文摘Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 workflow in such a network. All the sites in the network performed the annual reference dosimetry in water according to TG-51. These data were used to cross-calibrate the same ion chambers in plastic phantoms for monthly QA output measurements. An energy-specific dimensionless beam quality cross-calibration factor, <img src="Edit_6bfb9907-c034-4197-97a7-e8337a7fc21a.png" width="20" height="19" alt="" />, was derived to monitor the process across multiple sites. The SPC analysis was then performed to obtain the mean, <img src="Edit_c630a2dd-f714-4042-a46e-da0ca863cb41.png" width="30" height="20" alt="" /> , standard deviation, <span style="font-size:6.5pt;font-family:;" "=""><span style="white-space:normal;"><span style="font-size:6.5pt;font-family:"">σ</span><span style="white-space:nowrap;"><sub><i>k</i></sub></span></span></span>, the Upper Control Limit (UCL) and Lower Control Limit (LCL) in each beam. This process was first applied to 15 years of historical data at the main campus to assess the effectiveness of the process. A two-year prospective study including all 30 linear accelerators spread over the main campus and seven satellites in the network followed. The ranges of the control limits (±3σ) were found to be in the range of 1.7% - 2.6% and 3.3% - 4.2% for the main campus and the satellite sites respectively. The wider range in the satellite sites was attributed to variations in the workflow. Standardization of workflow was also found to be effective in narrowing the control limits. The SPC is effective in identifying variations in the workflow and was shown to be an effective tool in managing large network reference dosimetry.
基金Supported bythe Plan of New Technology Projectsin China National Packaging Corporation2005 (05ZBJA011)the Na-tional Natural Science Foundation of China (60373062) National Sci-ence Foundation of Hunan Province(04JJ3052)
文摘A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project risks. A model for optimizing software risk control is given, a discrete optimization algorithm based on dynamic programruing is proposed and an example of using above method to solve a problem is also included in this paper. By improving the old passive post-project control into an active effective preaction, this new method can greatly promote the possibility of success of software projects.
文摘为改善起重吊装碰撞风险预警反应时间短、过度预警等问题,开展基于改进统计过程控制(Improved Statistical Process Control,ISPC)的起重吊装防碰撞智能预警研究。建立ISPC模型,选择吊物与障碍物的距离为控制指标,设置中心线等生成控制图,确定预警规则;利用激光雷达获取障碍物点云,经坐标变换、滤波、聚类等处理,监测吊物与障碍物的距离;并设计塔吊吊装的模拟场景,测试ISPC模型的应用效果。结果表明:ISPC模型在两次试验下均及时发现吊物接近障碍物的异常状态,能够触发四类规则并实时预警。ISPC模型在起重吊装潜在碰撞风险的智能预警上提供理论和实践应用价值。
