Measuring hydraulic properties of geotextiles after installation damage

Since geotextiles have been progressively incorporated into coastal protection structures, the influence of installation damage on them has been the primary concern. During installation/construction, geotextiles are repeatedly subjected to high mechanical stresses which often exceed service stress. It is therefore vital to evaluate the mechanical and hydraulic damage and determine the consequences of these damages to better develop criteria for selection of suitable products. As these damages could reduce the material's mechanical strength and hydraulic efficiency, or in the severest form of damage, puncturing, would end the separation function. The properties investigated in this paper include the permittivity and apparent opening size (AOS) of geotextiles. Generally, the greater the drop energy of armour units applied to geotextiles, the greater the potential for damage. Findings show that the residual permittivity could increase significantly, 45% during installation. The preliminary design of coastal structures will be optimised as engineers and designers can better estimate the amount of damage on geotextiles upon installation.     

Introduction To Probability and Statistical Decision Theory

A nonparametric sequential rank correlation test for independence consisting of a generalized sequential probability ratio test is investigated through the Monte Carlo method. The test is found to be satisfactory in terms of the power function. Comparison of the expected sample size of the test and three other tests including the fixed sample size test suggests that the sequential rank test is also efficient.     

考工软件在维修电工技能考核故障检修项目中的应用

针对维修电工技能考核过程中存在的问题设计了一套半实物龙门刨床实训设备考工软件。该软件可通过键盘或教师机对在线实训装置进行故障设置和排除,记录、自动保存答题结果、故障的误排次数、考试时间、报警等信息,并在提交后发送给计算机进行评分,同时可对试卷自动保存,做到掉电不丢失,从而提高技能考核的效率。     

Response Surface Designs for Experiments with Mixtures

In estimating a response surface where the k variables represent proportions in a mixture, the experimenter is often interested in a reasonably well-defined region of interest which may, for example, center about current operating levels. Previously developed designs are difficult to use except in exploring the entire factor space, and even then there are several disadvantages to these designs. A general method of constructing designs from familiar response surface designs in k ? 1 independent variables and the appropriate analysis for a general polynomial is given. Special attention is given to the first and second order polynomials.     

Reactor protection system testing for the solid fuel thorium molten salt reactor

Safety system testing is one of the most rigorous and time-consuming requirements in the verification and validation process for reactor protection systems(RPSs).This paper presents the development of a test system for the fully digital and field-programmable gate array-based RPS of the solid fuel(SF) thorium-breeding molten salt pebble bed fluoride salt-cooled reactor(TMSR),denoted as the TMSR-SF1 project,developed by the Chinese Academy of Sciences.The test system is applied to the RPS to ensure that it fully meets its designed functions and system specifications.We first introduce the testing principles and methods.Then,the hardware component designs and the software program development of the test system are discussed.Finally,the test process and test results are discussed and summarized.     

FPGA-based test bed for measurement of AM/AM and AM/PM distortion and modeling memory effects in RF PAs

Using a field-programmable gate array (FPGA) development board, a digital signal processor (DSP) builder, and the phase-to-amplitude conversion principle, a low-cost system for measuring the amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) distortion curves of radio frequency (RF) power amplifiers (PAs) is presented. The state of the art based on the measurements and preliminary studies of AM/AM and AM/PM distortion curves is discussed. A full digital control of the test bed simulated/emulated in Matlab/Simulink is introduced to recalculate the known AM/AM and AM/PM measurements stored as look-up table (LUT). Finally, the low-cost system comprises the memory polynomial model (MPM) that involves the nonlinearity order and memory effects of real PAs.     

火箭发动机试验台快速高效高可靠试验技术

随着卫星系统组网及发射任务的增加,某运载火箭上面级发动机需求量猛增,试验系统和试验流程已经无法满足形势任务的需求。通过技术改造和流程优化,采用了一系列多余物控制、试验流程监控及可靠性提升等技术,实现了某试验台试验的快速、高效、高可靠,大大提高了试验效率。     

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.     

In the eye of the beholder: A simulator study of the impact of Google Glass on driving performance

This study examined whether, and to what extent, driving is affected by reading text on Google Glass. Reading text requires a high level of visual resources and can interfere with safe driving. However, it is currently unclear if the impact of reading text on a head-mounted display, such as Google Glass (Glass), will differ from that found with more traditional head-down electronic devices, such as a dash-mounted smartphone. A total of 20 drivers (22–48 years) completed the Lane Change Test while driving undistracted and while reading text on Glass and on a smartphone. Measures of lateral vehicle control and event detection were examined along with subjective workload and secondary task performance. Results revealed that drivers’ lane keeping ability was significantly impaired by reading text on both Glass and the smartphone. When using Glass, drivers also failed to detect a greater number of lane change signs compared to when using the phone or driving undistracted. In terms of subjective workload, drivers rated reading on Glass as subjectively easier than on the smartphone, which may possibly encourage greater use of this device while driving. Overall, the results suggest that, despite Glass allowing drivers to better maintain their visual attention on the forward scene, drivers are still not able to effectively divide their cognitive attention across the Glass display and the road environment, resulting in impaired driving performance.     

Theory-based metrological traceability in education: A reading measurement network

Huge resources are invested in metrology and standards in the natural sciences, engineering, and across a wide range of commercial technologies. Significant positive returns of human, social, environmental, and economic value on these investments have been sustained for decades. Proven methods for calibrating test and survey instruments in linear units are readily available, as are data- and theory-based methods for equating those instruments to a shared unit. Using these methods, metrological traceability is obtained in a variety of commercially available elementary and secondary English and Spanish language reading education programs in the U.S., Canada, Mexico, and Australia. Given established historical patterns, widespread routine reproduction of predicted text-based and instructional effects expressed in a common language and shared frame of reference may lead to significant developments in theory and practice. Opportunities for systematic implementations of teacher-driven lean thinking and continuous quality improvement methods may be of particular interest and value.