Discrete event simulation case study: Diagnostic path for stroke patients in a stroke unit

Hospitals aim at delivering efficient and effective healthcare. This requires high quality medical care, provided by highly trained and motivated professionals. Also the way operations are organized can contribute to a smoother healthcare delivery. An important point here is patient flow and waiting times during the patient trajectory diagnosis-therapy-care. Due to the large variability that exist between patients care needs, even for patients with a similar pathology, predicting the waiting times is very challenging. Traditional analytical optimization models like queuing theory cannot cope with the complexity of the pathways followed by patients and the interrelationships between the resources they need. Discrete event simulation can help to provide insight into the impact of operational changes, e.g. concerning available scanner capacity, on the timing of the patient’s trajectory in a hospital unit.This paper focuses on the diagnostic part of the stay of stroke patients in a stroke unit of a university hospital. With the help of discrete event simulation this patient flow is analyzed and the impact of potential changes in the capacity profile of test resources is investigated. The paper describes the steps taken in the study and the challenges met. The structure of the simulation program is explained and the results of the scenario analysis are discussed. The paper starts with a brief exploration of the use of discrete event simulation in healthcare and ends with general observations on the subject.     

Adaptive–interpolative binarization with stroke preservation for restoration of faint characters in degraded documents

A novel technique for binarization with stroke preservation of faint characters in degraded documents is proposed. It works in a multi-scale framework with an adaptive–interpolative thresholding technique. Instead of computing a global threshold value, it computes the local threshold values for a small set of grid points by observing the intensity pattern of the pixels lying in the concerned grid cells. Estimated thresholds are used, in turn, to compute the threshold values of all the remaining pixels using a fast-yet-efficient interpolation procedure. To handle noises in degraded images, this grid-based adaptive thresholding is applied in successively reducing scales to obtain the near-optimal binarization as a set of connected components. After a post-processing meant for stroke preservation with these connected components, we get the final output. Exhaustive experimentation and comparison with other existing methods have been successfully carried out with benchmark datasets and also with our own datasets.     

基于主曲线的书法字动态重现算法

如何高效逼真地动态重现书法作品的创作过程日益成为亟需解决的问题,因此文中提出基于主曲线的书法字动态重现方法,解决当前细化算法在提取骨架时存在的无效分支较多、不能保证笔画的连续性和准确性的问题.结合书法字自身结构对主曲线算法进行改进和优化.对书法图像进行骨架提取、骨架追踪、笔顺获取等处理,结合骨架信息和二值图像实现笔画宽度复原,针对笔画宽度存在的“肿瘤”问题,提出“角点剔除法”进行修正,结合HTML5的Canvas绘图技术进行书法字动态书写过程.在模拟数据集上的实验表明,文中算法的书法动态重现取得较好效果.     

Constructing Chinese characters: keypad design for mobile phones

Increased use of mobile phones and associated services in China highlights the need for effective Chinese input methods for mobile devices. Mapping thousands of characters to a standard telephone keypad is a significant challenge. Structure-based methods provide an appealing known-character/known-code solution, but assigning multiple strokes to each key forces users to learn new, often unfamiliar, mappings. Using an established stroke input method, our study revealed important effects of keypad legend on performance. Novice user performance was evaluated with several alternative keypad designs. The results confirmed that both abstract symbols and concrete examples helped improve the usability of the keypad in Chinese text-entry tasks. Further, combining abstract symbols and concrete examples resulted in performance nearly tripling as compared to the original design. The stroke-to-key mapping accuracy also increased significantly. Handwriting analysis confirmed that the reduced errors are directly associated with the keypad-based text-entry technique.     

The Analysis of the Lubrication Condition and Friction Losses of a Single Acting Cross Head Guide Shoe of a Low Speed Cross Head Diesel Engine: Part II — A Practical Model for the Determination of the Oil Film Thickness

The cross head guide shoe plate of a large diesel engine operates under a large normal force which presses it against the rails between which it executes both axial and transverse motion. In order to ensure the safe operation of an unconventional bearing such as the guide shoe system of the cross head engine, an algorithm that can be used to predict accurately the oil film thickness that can be achieved for all the engine's operating regimes, is invaluable. A solution of the three dimensional form of Reynolds differential equation can provide the requisite oil film thickness. However, with even the availability of very fast computers and large computer storage capacity this solution for a large axial bearing such as the guide shoe becomes impractical in terms of computation time and computer core requirements. This paper describes alternative simplified algorithm for accurate prediction of the oil film thickness developed in the guide shoe bearing at different operating regimes of the engine.     

R108A型柴油机的开发研制

本文就由R105系列柴油机经扩缸、加长行程为R108A系列柴油机的研制开发过程作了介绍,较为详细的说明了零部件的结构设计及整机的性能和可靠性。     

钻井泥浆泵对中问题探讨

应用引进美国油井公司技术,生产出口F、P系列泥浆泵,针对其冲程找正要求,通过对其运动原理的分析研究,设计了一系列工具和找正程序,解决了泥浆泵的对中问题,取得了使易损件寿命延长,泥浆泵发挥最高工作效率的较好效果。     

氦氖激光联合左氧氟沙星针及护理治疗脑卒中并发Ⅲ-Ⅳ期压疮的效果评价

探讨氦氖激光照射联合左氧氟沙星针及护理治疗脑卒中并发Ⅲ-Ⅳ期压疮的疗效。将48例院外带入压疮的脑卒中患者随机分成实验组和对照组,各24例。对照组实施神经内科护理常规,并清洁创面后用左氧氟沙星针纱布湿敷;实验组清创后每天用氦氖激光照射压疮表面15至20 min,再用左氧氟沙星针纱布湿敷,并给予有针对性的护理干预。治疗4周后观察压疮愈合情况。对照组有效率为69.70%,实验组有效率为90.91%。两组差异比较(P0.005),有统计学意义。氦氖激光联合左氧氟沙星针治疗护理更有利于Ⅲ-Ⅳ期压疮的肉芽生长和上皮爬行,促进压疮创面愈合,缩短了压疮愈合时间。     

脑卒中患者下肢外骨骼康复机器人步态规划与运动学仿真

为满足越来越多的脑卒中患者辅助行走和康复训练的需要,设计了一款下肢外骨骼机器人模型,采用D-H参数法建立踝关节、膝关节、髋关节坐标系,推演出步态周期内的坐标方程。为了安全起见,要求脑卒中患者步行速度慢且步长短,利用CoG(Center of Gravity,重心地面投影点)作为步态规划中的稳定性判断依据,并用Robotics Toolbox for Matlab仿真,结果表明:下肢外骨骼康复机器人在康复训练过程中各关节具有连续且稳定的步态轨迹,为后续脑卒中患者使用的下肢外骨骼康复机器人样机研制提供了必要的理论依据。     

动态矫正衣对脑卒中偏瘫患者平衡和步行功能的即刻影响

目的:观察动态矫正衣对脑卒中偏瘫患者平衡功能和步行功能的即刻影响。方法:30例脑卒中后偏瘫患者在穿戴动态矫正衣前、穿戴动态矫正衣进行适应性训练5min后,分别应用BIODEX平衡评估系统评估患者站立位下的摆动指数(Sway Index),应用数字化跑台步态分析系统评估患者步行时的躯干屈伸角度、躯干侧弯角度、负重对称性,3m起立-行走测试(3m TUGT)、10m步行速度测试(10M WST)对患者进行平衡和步行功能的评估。结果:患者穿戴动态矫正衣后即刻站立位下的摆动指数(Sway Index)无论在稳定平面还是在泡沫软垫不稳定平面均较穿戴前明显下降(P<0.05),而且闭眼情况下,均较睁眼时下降更明显,差异具有统计学意义(P<0.05)。步行时躯干屈伸、侧弯角度、负重对称性较穿戴前明显改善(P<0.05)。而3M TUGT、10M WST时间均较穿戴前明显延长,差异具有统计学意义(P<0.05)。结论:穿戴动态矫正衣即刻即可提高脑卒中后偏瘫患者的站立平衡及步行稳定性。但也因穿戴后躯干代偿减少,导致患者短时间内活动速度下降。