基于网络的智能化通用机试系统的设计与实现

本文介绍了网络环境下,基于ASP技术网络通用考试系统的特点、主要功能以及其中的关键实现技术。

计算机基础机试系统的研究和实现

本文介绍了一个计算机基础课程的机试系统 ,本系统可以实现考生、题库、考试及阅卷的管理 ,并从理论和具体实现两个方面对系统进行了分析和论述。

标准化机试系统的开发与关键技术的创新

上机考试是计算机教育中的重要环节。结合笔者多年开发标准化机试系统的经验,详细阐述了常用机试系统的原理、缺陷,并提出改进方法及新的解决方案。在已有基础上,设计出更加科学实用的系统,发展并拓宽了现有考试系统的应用范围。通过给出无相邻重复的随机抽题算法,确保了随机抽题的公正性。

基于TCP/IP的机试系统

本文通过分析原有的计算机机试软件系统的缺点 ,提出一个基于TCP/IP协议下的计算机机试软件架构 ,解决了原有计算机机试软件系统存在的问题 。

基于移动Agent的计算机机试考试系统研究

目的改进传统计算机机试考试系统的相关局限性。方法利用移动Agent在网络中的迁移性及其智能性和自主性的特点,重新研究并设计了一种基于移动Agent模型的系统设计方案。结果这种新的模型能够有效地减少网络带宽的占用,大大提高了系统的可靠性。结论该系统模型具有较好的健壮性、易用性、可靠性和分布性,可以应用于其它需要大规模协作的系统的设计。

Does antecolic reconstruction for duodenojejunostomy improve delayed gastric emptying after pylorus-preserving pancreaticoduodenectomy? A systematic review and meta-analysis

AIM:To evaluate whether antecolic reconstruction for duodenojejunostomy (DJ) can decrease delayed gastric emptying (DGE) rate after pylorus-preserving pancreaticoduodenectomy (PPPD) through literature review and meta-analysis. METHODS:Articles published between January 1991 and April 2012 comparing antecolic and retrocolic reconstruction for DJ after PPPD were retrieved from the databases of MEDLINE (PubMed), EMBASE, OVID and Cochrane Library Central. The primary outcome of interest was DGE. Either fixed effects model or random effects model was used to assess the pooled effect based on the heterogeneity. RESULTS:Five articles were identified for inclusion:two randomized controlled trials and three non-randomized controlled trials. The meta-analysis revealed that antecolic reconstruction for DJ after PPPD was associated with a statistically significant decrease in the incidence of DGE [odds ratio (OR), 0.06; 95% CI, 0.02-0.17; P < 0.00 001] and intra-operative blood loss [mean difference (MD), -317.68; 95% CI, -416.67 to -218.70; P < 0.00 001]. There was no significant difference between the groups of antecolic and retrocolic reconstruction in operative time (MD, 25.23; 95% CI, -14.37 to 64.83; P = 0.21), postoperative mortality, overall morbidity (OR, 0.54; 95% CI, 0.20-1.46; P = 0.22) and length of postoperative hospital stay (MD, -9.08; 95% CI, -21.28 to 3.11; P = 0.14). CONCLUSION:Antecolic reconstruction for DJ can decrease the DGE rate after PPPD.

Virtual test system for permanent-magnet DC motor

In order to obtain the primary parameters and operating characteristics of a DC motor without directly measuring its torque and rational speed, it is proposed to use a PC and a data acquisition card to acquire both the dynamic and static data of armature current to establish the performance of a DC permanent magnet motor. The accuracy and validity of this virtual test system proposed were verified by comparing the measurements made with the system proposed with the measurements made with conventional torque meters. It is concluded from the results of comparison that from the mathematic model established for the DC permant magnet motors, both major parameters and operating characteristics can be directly established for the DC motors without measuring their torques and rotational speed, a perfect on line measurement and test system has been established for the DC permanent magnet motors using the theory of virtual test system. The system proposed features shorter test time, higher efficiency and lower cost.

Fluent-based numerical simulation of flow centrifugal fan

Testing centrifugal fan flow field by physical laboratory is difficult because the testing system is complex and the workload is heavy, and the results observed by naked-eye deviates far from the actual value. To address this problem, the computational fluid dynamics software FLUENT was applied to establish three-dimensional model of the centrifugal fan. The numeral model was verified by comparing simulation data to experimental data. The pressure centrifugal fan and the speed changes in distribution in centrifugal fan was simulated by computational fluid dynamics soft-ware FLUENT. The simulation results show that the gas flow velocity in the impeller increases with impeller radius increase. Static pressure gradually increases when gas from the fan access is imported through fan impeller leaving fans.

Association of traditional Chinese exercises with glycemic responses in people with type 2 diabetes:A systematic review and meta-analysis of randomized controlled trials

Background： There is increasing evidence showing the health benefits of various forms of traditional Chinese exercises （TCEs） on the glycemic profile in people with type 2 diabetes. However, relatively little is known about the combined clinical effectiveness of these traditional exercises. This study was designed to perform a systematic review and meta-analysis of the overall effect of 3 common TCEs （Tai Ji Quan, Qigong, Ba Duan Jin） on glycemie control in adults with type 2 diabetes. Methods： We conducted an extensive database search in Cochrane Library, EMBASE, PubMed, Web of Science, EBSCO, and China National Knowledge Infrastructure on randomized controlled trials published between April 1967 and September 2017 that compared any of the 3 TCEs with a control or comparison group on glycemic control. Data extraction was performed by 2 independent reviewers. Study quality was evaluated using the Coehrane Handbook for Systematic Reviews of Interventions, which assessed the risk of bias, including sequence generation, allocation concealment, blinding, completeness of outcome data, and selective outcome reporting. The resulting quality of the reviewed studies was characterized in 3 grades representing the level of bias： low, unclear, and high. All analyses were performed using random effects models and heterogeneity was quantified. We a priori specified changes in biomarkers of hemoglobin A1 c （in percentage） and fasting blood glucose （mmol/L） as the main outcomes and triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein-cholesterol, 2-h plasma glucose, and fasting plasma glucose as secondary outcomes.Results： A total of 39 randomized, controlled trials （Tai Ji Quan = 11; Qigong= 6; Ba Duan Jin= 22） with 2917 type 2 diabetic patients （aged 41-80 years） were identified. Compared with a control or comparison group, pooled meta-analyses of TCEs showed a significant decrease in hemoglobin Alc （mean difference （MD）= -0.67%; 95% confidence interval （CI）：-0.86% to-0.48%; p 〈 0.00001） and fasting blood glucose （MD = -0.66 mmol/L; 95%CI： -0.95 to -0.37 mmol/L; p 〈 0.0001）. The observed effect was more pronounced for interventions that were medium range in duration （i.e., 〉3-〈 12 months）. TCE interventions also showed improvements in the secondary outcome measures. A high risk of bias was observed in the areas of blinding （i.e., study participants and personnel, and outcome assessment）. Conclusion： Among patients with type 2 diabetes, TCEs were associated with significantly lower hemoglobin Alc and fasting blood glucose. Further studies to better understand the dose and duration of exposure to TCEs are warranted.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.

Network Management of Food Additives Quality Analysis and Inspection

In this paper, on the basis of the implementation of the national chemical industry standard analytical test methods and analysis of test items, a food additive quality analysis and inspection of network management applications are developed using the development technology of Visual Basic language and computer system operating environment, to achieve a network management software for users on food additives of quality analytical testing. The software sets up an information sharing network platform for enterprise and quality management departments, which is a major innovation in the food additive quality analysis on test management methods and tools.

Acupuncture for hyperlipidaemia in adults： A systematic review and meta-analysis

Objective： To assess the efficacy and safety of acupuncture for hyperlipidemia in adults. Methods： We searched electronic databases, including PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, CBM, CNKI, and VIP. All included studies were assessed in terms of quality and risk bias. The Review Manager 5.3.3 software was used for the data analyses, and the GRADE profiler software was applied to classify the systematic review results. Results： Seventeen studies were identified （n = 1,408）. Acupuncture （electro-acupuncture or magnetic needle） was equally as effective as sham treatment （needle acupuncture） （relative risk [RR], 0.95; 95% confidence interval [CI], 0.72-1.24）. Acupuncture （needle acupuncture, electro-acupuncture, moxibustion, and acupoint catgut embedding） was as effective as statin therapy （RR 0.10; 95%CI, 0.97-1.24）. Acupuncture was as effective as Chinese herbal preparations （electro-acupuncture and auricular acupoint） （RR, 0.97; 95%CI, 0.89-1.06）. However, insufficient evidence was available to demonstrate whether acupressure was effective compared with acupuncture plus other treatments （RR, 1.04; 95%CI, 0.87-1.25）. Conclusion： Acupuncture may improve hyperlipidemia levels. However, additional large, properly randomized, placebo-controlled, double-blind studies are required.

Simulation and experimental study on hydraulic driving fan cooling system for construction machinery working on plateau

Overheating of the engine, the transmission and the hydraulic device is a problem when the construction machinery works on plateau. To solve this problem, we proposed an electro-controlled hydraulic driving fan cooling system (ECHDFCS). The system was applied to a 50-wheel loader. We carried out the coolant temperature simulation using fluid modeling software FLOWMASTER, followed by laboratory experiments and road tests. The results show that ECHDFCS can adjust the cooling capability of the system automatically based on machine heat dissipation requirements. The coolant temperature is consequently remained within an appropriate range. The simulation results are consistent with the experiment results when the experiment is performed on the plain, but are different from the road tests in some investigated parameters on the plateau.

Hemihepatic versus total hepatic inflow occlusion during hepatectomy:A systematic review and meta-analysis

AIM： To evaluate the clinical outcomes of patients undergoing hepatectomy with hemihepatic vascular occlusion （HHO） compared with total hepatic inflow occlusion （THO）. METHODS： Randomized controlled trials （RCTs） co- mparing hemihepatic vascular occlusion and total he- patic inflow occlusion were included by a systematic literature search. Two authors independently assessed the trials for inclusion and extracted the data. A meta- analysis was conducted to estimate blood loss, transfu- sion requirement, and liver injury based on the levels of aspartate aminotransferase （AST） and alanine arni- notransferase （ALT）. Either the fixed effects model or random effects model was used. RESULTS- Four RCTs including 338 patients met the predefined inclusion criteria. A total of 167 patients were treated with THO and 171 with HHO. Metaanalysis of AST levels on postoperative day 1 indicated higher levels in the THO group with weighted mean dif- ference （WMD） 342.27; 95% confidence intervals （CI） 217.28-467.26; P = 0.00001; I2 = 16%. Meta-analysis showed no significant difference between THO group and HHO group on blood loss, transfusion requirement, mortality, morbidity, operating time, ischemic duration, hospital stay, ALT levels on postoperative day 1, 3 and 7 and AST levels on postoperative day 3 and 7. CONCLUSION： Hemihepatic vascular occlusion does not offer satisfying benefit to the patients undergoing hepatic resection. However, they have less liver injury after liver resections.

Telemonitoring and hemodynamic monitoring to reduce hospitalization rates in heart failure： a systematic review and meta-analysis of randomized controlled trials and real-world studies

Background Heart failure is a significant problem leading to repeated hospitalizations. Telemonitoring and hemodynamic monitoring have demonstrated success in reducing hospitalization rates, but not all studies reported significant effects. The aim of this systematic review and meta-analysis is to examine the effectiveness of telemonitoring and wireless hemodynamic monitoring devices in reducing hospitalizations in heart failure. Methods ＆ Results PubMed and Cochrane Library were searched up to 1st May 2017 for articles that investigated the effects of telemonitoring or hemodynamic monitoring on hospitalization rates in heart failure. In 31,501 patients （mean age： 68 ± 12 years; 61% male; follow-up 11 ± 8 months）, telemonitoring reduced hospitalization rates with a HR of 0.73 （95% CI： 0.65-0.83; P 〈 0.0001） with significant heterogeneity （I2 = 94%）. These effects were observed in the short-term （≤ 6 months： HR = 0.77, 95% CI： 0.65-0.89; P 〈 0.01） and long-term （≥ 12 months： HR = 0.73, 95% CI： 0.62-0.87; P 〈 0.0001）. In 4831 patients （mean age 66 ± 18 years; 66% male; follow-up 13 ± 4 months）, wireless hemodynamic monitoring also reduced hospitalization rates with a HR of 0.60 （95% CI： 0.53-0.69; P 〈 0.001） with significant heterogeneity （I2 = 64%）.This reduction was observed both in the short-term （HR = 0.55, 95% CI： 0.45-0.68; P 〈 0.001; I2 = 72%） and long-term （HR = 0.64, 95% CI： 0.57-0.72; P 〈 0.001; I2 = 55%）. Conclusions Telemonitoring and hemodynamic monitoring reduce hospitalization in both short- and long-term in heart failure patients

Test Bench for Robotics and Autonomy： Overview and Test Results

In this paper, the TAS-I （Thales Alenia Space-Italy） Test Bench for Robotics and Autonomy （TBRA） is presented. It is based on a flexible and modular software architecture （Framework Engine）, in which each functional module （representing the GNC subsystems） implements a key functionality of the GNC （Guidance Navigation and Control）. Modules communicate by means of standardised interfaces designed for exchange of necessary information among the modules composing the entire system. This approach permits the interchange-ability of each subsystem without affecting the overall functionalities of the GNC system. In this paper, the TBRA system, together with the implemented functional modules will be described. Tests results will be reported and future development will be discussed.

MEMS Test System Based on Virtual Instrument Technology

On account of the multiformity of MEMS devices, it is necessary to integrate with some optical measurement techniques for meeting static and dynamic unit test requirements. In this paper, an automated MEMS test system is built of some commercially available components and instruments based on virtual instrument technology. The system is integrated with stroboscopic imaging, computer micro-vision, microscopic Mirau phase shifting interferometry, and laser Doppler vibrometer, and is used for the measurement of full-view in-plane and out-of-plane geometric parameters and periodical motions and single spot out-of-plane transient motion. The system configuration and measurement methods are analyzed, and some applications of the measurement of in-plane and out-of-plane dimensions and motions were described. The measurement accuracy of in-plane dimensions and out-of-plane dimensional is better than 0.2 um and 5 nm respectively. The resolution of measuring in-plane and out-of-plane motions is better than 15 nm and 2 nm respectively.

An Assessment of Eco Driving System for Agricultural Tractor

In this study, tractor power output, fuel consumption rate and work performance were indirectly predicted in order to develop an eco driving system. Firstly, equations were developed which could foretell tractor power output and fuel consumption rate using characteristic curves of tractor power output. Secondly, with actual engine revolution per minute （rpm） determined by initial engine rpm and work load, tractor power output and fuel consumption rate were forecasted. Thirdly, it was possible to foresee tractor work performance and fuel consumption rate by the speed signals of Global Positioning System （GPS）. Lastly, precision of the eco driving system was evaluated through tractor Power Take-Off （PTO） test, and effects of the eco driving system were investigated in the plowing and rotary tilling operations. Engine rpm, power output, fuel consumption rate, work performance and fuel consumption rate per plot area were displayed on the eco driving system. Predicted tractor power outputs in the full load curve were well coincided with the actual power output of prototype, but small differences, 1 to 6 kW were found in the part load curve. Error of the fuel consumption rate was 0.5 to 3 L/h at the part load curve. It was shown that 69% and 53% of fuel consumption rates could be reduced in plowing and rotary tilling operations, respectively, when the eco driving system was installed in tractor.

Development of testing techniques for mine fan performance

Three progressive stages of testing techniques are elaborated,which are en-tirely manual operating,taking separate instruments testing and computer program con-trolling.The testing method and principle are detailed based on the testing process formeteorological parameters,air pressure,air quality and rotating velocity.And every testingtechnique is analyzed.Finally, the technique outlook is viewed.All this plays a leading rolein development of the testing techniques.

Development of a Small-Scale Universal Apparatus for Evaluating Soil-Structure Interaction

This paper describes design and calibration procedures of a new small-scale testing apparatus for evaluating soil-structure interaction. Two distinct modes of loadings, such as, direct shear and pullout loadings on flexible and rigid reinforcements are implemented by the multiple functionalities of the apparatus through the use of single loading frame, dividing mechanism, instrumentation and data acquisition systems. The design is similar to the conventional apparatus; however, it includes some key modifications to adapt additional features of reinforcements. For the pullout test, the top half of the pullout box is fixed with the bottom half of the pullout box, while for the direct shear test, the top half is allowed to slide horizontally on low friction roller bearings connected to the driving mechanism. Mechanical loadings through a steel plate are used to apply the normal load in the pullout and direct shear apparatus. A series of shear and pullout tests are performed to validate the functionality of the apparatus and to examine relationships between the reinforcements and its shear and pullout resistances.

Semi-physical simulation of AUV pipeline tracking

Before the task of autonomous underwater vehicle(AUV) was implemented actually,its semi-physical simulation system of pipeline tracking had been designed.This semi-physical simulation system was used to test the software logic,hardware architecture,data interface and reliability of the control system.To implement this system,the whole system plan,including interface computer and the methods of pipeline tracking,was described.Compared to numerical simulation,the semi-physical simulation was used to test the real software and hardware more veritably.In the semi-physical simulation system,tracking experiments of both straight lines and polygonal lines were carried out,considering the influence of ocean current and the situation of buried pipeline.The experimental results indicate that the AUV can do pipeline tracking task,when angles of pipeline are 15°,30°,45° and 60°.In the ocean current of 2 knots,AUV could track buried pipeline.