摘要：The concept of facial impact protection mask for cyclists is proposed in response to increased participation in cycling and the need for injury prevention. The research aims to develop an approach for design of facial impact protection gear to reduce the risk of severe injury. Impact test equipment and procedure, face surrogate and protection material performance criteria are developed. Three groups of protective materials – rigid crushable, semi rigid, and soft cushion foams are tested and assessed according to criteria. The criteria are linked to measures of the risk of facial and brain injuries: HIC (Head Injury Criterion), peak deceleration, Face-bone damage and energy absorption. The impact energy is simulated by a drop test using a 48 mm-radius-steel hemispherical impactor, with a weight of 4.63 kg similar to that of headform J specified in AS/NZS standard. The drop-height is 1500 mm, and the linear deceleration force of the impactor is recorded and used to establish the performance of the materials. The HIC is used to predict the risk of brain injury, whereas the developed face surrogate is used to assess facial bone injury. A 5.4 m/s facial impact to the unprotected-face of a cyclist can result in the risk of severe facial bone fracture and mild brain injury. The impact test results for rigid foam protection of 40 mm thickness shows no densification (bottom out) and absorbs the impact energy without damage to the Foam-bone of the face surrogate. At 20 mm thickness, rigid polyurethane foams performed best with Foam-bone damage ranging from 15.1% to 20.5%. Other materials with thicknesses of 20 to 28 mm showed Foam-bone damage between 21.8% and 35.1%. The HIC values ranged from 267 to 522, with memory foams and expanded polystyrene foam having the lowest values. Peak deceleration ranged from 71 g to 105 g for the materials tested. It is concluded that the impact energy can be dissipated by the protection material thereby reducing the risk of severe facial inju

摘要：目的:探讨遗传算法的局限性和实用性,并分析基于相互作用产生的上位效应对遗传算法可靠性的影响。创新点:1.指出遗传算法缺陷的根源;2.基于测试样本函数定义目标函数,以判断遗传算法的适用性。方法:1.基于非上位效应函数(表1)和上位效应函数(表2),以及非上位效应函数F4和上位效应函数F6的结构图来验证遗传算法可靠性;2.通过计算样本函数(公式(1))和遗传算法流程(图3)表达遗传算法的工作原理。3.利用克洛弗函数(公式(2))和计算不同结构角下的函数分布(图4),进一步判断匹配度(表3)和计算效率(表4);定义新的目标函数(公式(9))和一组新的变量(公式(10))来实现变量相关性解离。结论:1.对当前遗传算法存在的不足给出了独到见解,并认为正定性的假设并非可以保证遗传算法实际的有效性和优化性。2.定义成本代价函数用以判断遗传算法可靠性,并分别考虑上位性和非上位性效应两种情形。当成本代价函数在非上位性效应下时,遗传算法是有效的;否则,可以把N维函数降级为N个一维函数,从而采用更简单的算法来判断。基于一些通用的基准,进一步设计三类样本函数来证实以上判断,且这些样本函数适合于上位性效应情形和非上位效应情形。3.遗传算法的瓶颈在于主算子和相干匹配性;可以通过破坏某些结构来实现变量关系的解离,从而抑制相干匹配性对遗传算法的影响。希望相关读者在处理实际优化问题时能验证作者关于上位效应的定性结论,并给出更可靠的方法来表征这种效应。

摘要：Mango fruit (Mangifera indica) is very rich in fibre and vitamin C which are the required nutrients for good health and easy digestion of food in human body system. However, the fruit is highly perishable in its natural state after harvest due to the chemical deterioration and environmental effects. Due to the perishable nature, abundant wastage during the production season and relative scarcity during the off season were recorded by farmers. Processing the fruit into the form that can easily be stored, preserved, packaged, transported or consumed is crucial to having the product all the year round. Besides, mango juice can be consumed freshly, processed into dry powder, mixed or blended with other juice to make fruit jams, or evaporated to concentrates. These products have a lot of potential in food and beverage industries for export and foreign exchange earnings. Therefore, a small scale machine to process mango fruits to high quality juice is highly essential to reduce the postharvest loss and then add value to the commodity. To achieve this purpose, an abrasion-macerating device (AMD) was designed, fabricated and tested for small scale mango juice extraction. Design considerations focused on the techno-economic status of the micro and small scale fruit juice processors who are the intended users of the machine. The major components of the machine included hopper, perforated drum, screw conveyor, juice outlet, waste outlet, frame, electric motor and motor stand. Other components included screw shaft, the juice collector, top cover and the transmission system. In operation, the screw conveyor conveys and presses the mango fruits against the perforated roughened drum. The abrasion/tearing process of the screw on the flesh of the fruit and further pressing against the drum squeeze enough juice out of the fruit. The juice extracted is drained through the perforated mesh of the juice channel into the juice outlet from where it is collected while the residual waste is

摘要：为了满足皮纳卫星、立方星的姿态控制精度要求,提高微型反作用飞轮控制精度,基于开关式霍尔元件,设计测速与控制总体方案,提出一种将变分频T法与带速度切换迟滞环的滑动均值滤波相结合的速度估计方法,提高测速精度,并采用积分分离的离散PID算法防止控制饱和.结果表明:速度控制的最大误差≤1.5%,平均误差≤0.4‰,误差方差≈0.25.2016年6月25日,该飞轮随世界首颗12U立方星"翱翔之星"搭载"长征7号"发射入轨,实现卫星三轴稳定,在轨服役99d直到卫星坠入大气层,圆满完成任务.地面测试与在轨运行结果表明,所采用的方案有效可行,速度估计与控制算法能够满足卫星姿态控制系统的任务需求.

摘要：This paper addresses the problem of channel estimation in 5G-enabled vehicular-to-vehicular(V2V) channels with high-mobility environments and non-stationary feature. Considering orthogonal frequency division multiplexing(OFDM) system, we perform extended Kalman filter(EKF) for channel estimation in conjunction with Iterative Detector & Decoder(IDD) at the receiver to improve the estimation accuracy. The EKF is proposed for jointly estimating the channel frequency response and the time-varying time correlation coefficients. And the IDD structure is adopted to reduce the estimation errors in EKF. The simulation results show that, compared with traditional methods, the proposed method effectively promotes the system performance.

摘要：A novel Discrete Wavelet Transform (DWT) based Hidden Markov Module (HMM) for face recognition is presented in this letter. To improve the accuracy of HMM based face recognition algorithm, DWT is used to replace Discrete Cosine Transform (DCT) for observation sequence ex- traction. Extensive experiments are conducted on two public databases and the results show that the proposed method can improve the accuracy significantly, especially when the face database is large and only few training images are available.

摘要：This paper presents a free viewpoint video(FVV)system based on ray-space interpolation *** new algorithm matches individual pixels in corresponding scanline pairs by using a dynamic program-ming technique.A sparse intermediate view disparity map is projected from matched pixels firstly,andthe holes(occluded pixels)are filled in by propagating the disparity of neighboring background *** interpolating dense view images,an arbitrary virtual view image can be easily rendered from thedense ray-space converted from these view *** proposed method is evaluated on the Middleburydata set arid compared with other methods,experimental results show that the better quality of the inter-mediate view is obtained and the corresponding computational complexity is reduced significantly.

摘要：动态波浪的路由模型城市不稳定并且非压力雨管子流动被质量，动量和精力的保存建立，并且它被使用四个点解决含蓄的差别方法和追求方法。它从检查的实验和动态波浪的路由模型能反映的比较分析被获得影响象一样稀释并且回水什么时候充满山峰与高计算精确和广阔申请在管道宣传范围，和它能在不同斜坡和流入条件的城市的雨管子流动的路由被使用。路由模型为镇降雨供应一个科学基础尖设计或检查，暴风雨流量的灾难管理等等。

摘要：The design of a wireless water level control system is introduced and discussed in detail. In this system, the wireless Proportional Integral (PI) controller is developed using the LabVIEW graphical user programming language. Zigbee wireless technology is chosen for the wireless data transfer system. The experimental testbed was built and the system software and hardware were implemented. In order to compare the performance of the wired and wireless system, a corresponding wired water level control system was built. Experimental results show that under the same PI parameters, the settling time of the wired system is 3.3 times faster than the wireless system. However, the percent overshoot using the wireless controller is 4% smaller.

摘要：In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced by digitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical physics but also led to a much finer precision of 1 mili arc sec or less. As examples of the application of the proposed digitalised optics, two case studies have been given： a 10 m Schmidt telescope （off-axis） and an 8 m Cassegrain telescope （on-axis）.