基于.net技术的自动化立体仓库管理与控制系统的研究与实现

研究并开发了基于.net的自动化立体仓库管理与控制系统。该系统运行于微软.net平台,采用ASP.NET技术和ADO.NET技术,实现了仓库所需的各项业务操作并具有界面友好、便于维护、信息共享性及扩展性好等许多优点,为实现仓储物资可视化提供了一个有价值的解决方案。     

Optimal joint design of orthonormal real valued short time block code and linear transceiver

The main contribution of this paper is to propose an optimal joint design of an orthonormal real valued short time block code and a linear transceiver for multi-input/multi-output (MIMO) wireless digital communication systems. Firstly, a relaxed zero forcing condition based on both the short time block code and the linear transceiver is optimally derived via the Karhunen–Loève Transform (KLT) approach. The relaxed zero forcing condition guarantees that there is no transmission error under a noise free environment. Secondly, the linear transceiver is optimally designed via the orthogonal Procrustes approach. In particular, the transmission power gain is minimised subject to a specification on the ratio of the signal gain to the noise gain as well as to the relaxed zero forcing condition. Computer numerical simulation results show that our proposed optimal joint design of the orthonormal real valued short time block code and the linear transceiver can significantly improve the performances of MIMO wireless digital communication systems.     

Efficient and High-quality Recommendations via Momentum-incorporated Parallel Stochastic Gradient Descent-Based Learning

A recommender system (RS) relying on latent factor analysis usually adopts stochastic gradient descent (SGD) as its learning algorithm. However, owing to its serial mechanism, an SGD algorithm suffers from low efficiency and scalability when handling large-scale industrial problems. Aiming at addressing this issue, this study proposes a momentum-incorporated parallel stochastic gradient descent (MPSGD) algorithm, whose main idea is two-fold: a) implementing parallelization via a novel data-splitting strategy, and b) accelerating convergence rate by integrating momentum effects into its training process. With it, an MPSGD-based latent factor (MLF) model is achieved, which is capable of performing efficient and high-quality recommendations. Experimental results on four high-dimensional and sparse matrices generated by industrial RS indicate that owing to an MPSGD algorithm, an MLF model outperforms the existing state-of-the-art ones in both computational efficiency and scalability.      

Recent progress in magnetocaloric effect: Mechanisms and potential applications

Recent results in understanding of the magnetocaloric effect (MCE) mechanisms in the framework of thermodynamic approach are regarded and discussed. Importance of relation between ΔS_MT (magnetic entropy change at constant temperature) and ΔS_MH (magnetic entropy change at constant field) and it influence on MCE value is considered. The main contributions to the MCE are discussed. The importance of further development of models of interactions between magnetic and structural subsystems in vicinity of magnetic phase transitions is stressed. It is stated that the present level of MCE parameters (in particular, adiabatic temperature change) can be increased up to 3 times. The necessity of investigation of MCE parameters in dynamic mode and development of new experimental methods and apparatuses for MCE measurements is discussed. The most obvious application for MCE for today is magnetic refrigeration, but MCE also can be used for other applications such as medicine (hyperthermia, drug delivering), etc., which are regarded.     

一种多用途串口转换器的设计与实现

本文设计了一种多用途串口转换器,主要实现了以下功能:USB-RS232-TTL自动切换功能、RS232的收发自动切换功能及其热插拔功能、TTL的RXD-TXD收发自动切换功能及供电电源的正负极自动切换功能。该转换器实现了这三种常用接口的自动切换,为调试电路提供了方便。     

Stochastic fracture mechanics using polynomial chaos

Crack propagation in metals has long been recognized as a stochastic process. As a consequence, crack propagation rates have been modeled as random variables or as random processes of the continuous. On the other hand, polynomial chaos is a known powerful tool to represent general second order random variables or processes. Hence, it is natural to use polynomial chaos to represent random crack propagation data: nevertheless, no such application has been found in the published literature. In the present article, the large replicate experimental results of Virkler et al. and Ghonem and Dore are used to illustrate how polynomial chaos can be used to obtain accurate representations of random crack propagation data. Hermite polynomials indexed in stationary Gaussian stochastic processes are used to represent the logarithm of crack propagation rates as a function of the logarithm of stress intensity factor ranges. As a result, crack propagation rates become log-normally distributed, as observed from experimental data. The Karhunen–Loève expansion is used to represent the Gaussian process in the polynomial chaos basis. The analytical polynomial chaos representations derived herein are shown to be very accurate, and can be employed in predicting the reliability of structural components subject to fatigue.     

Numerical verification of the continuous calculation method for tip stress during the driving process of the dynamic penetration test

This paper presents a calculation method for obtaining the continuous variation in stress between the tip and the soil during dynamic penetration tests, particularly in the case of using the Panda 3® penetration testing device. The originality of the method is that the tip stress can be computed continuously throughout the driving process. For each impact of the hammer on the penetrometer, data are recorded by sensors located at the top of the apparatus. Then, the stress at the tip and the displacement of the apparatus are calculated with a method based on the propagation of waves in the device. A three-dimensional numerical model of the penetration test, based on the Panda 3® specifications and using the discrete element method (DEM), is proposed in this paper. The purpose of the simulations is to validate the calculation method by comparing the curves of the tip stress versus the penetration distance obtained in two different ways, the first being the distance directly observed at the tip and the second being the distance calculated from the data recorded at the top of the penetrometer, as with the experimental device. The entire apparatus is represented, including the hammer, the rod, and the tip, and is driven into the model soil. The calculation method is applied, and the results are compared to the actual response of the soil to the driving of the penetrometer directly at the tip, which can be obtained with the numerical model. The responses are found to be very similar, confirming the theoretical framework and its underlying assumptions. This method is applied to dynamic penetration tests and provides the opportunity to obtain mechanical parameters other than the tip resistance from the tests.     

新型瓦斯检测系统硬件设计

针对矿用瓦斯检测系统中使用传感器的特点以及工作环境,加入温度、湿度数据采集环节,在软件算法方面提高测量准确度。设计中主要采用高共模抑制比的差分放大电路、开关电容滤波器提高信号源的精确度,同时抑制电源噪声以提高系统抗干扰性。     

Simulation and validation of a hybrid-power gas engine heat pump

Hybrid-power gas engine heat pump (HPGHP) combines hybrid power technology with gas engine heat pump, which can keep the gas engine working in the economical zone. In this paper, a steady-state model of the HPGHP in heating condition has been established, the optimal torque curve control strategy is proposed to distribute power between the gas engine and battery pack. The main operating parameters of the HPGHP system are simulated on Matlab/Simulink and validated by experimental data, such as operating temperature, coefficient of performance (COP), fuel-consumed rate, etc. Heating capacity and COP of the heating pump system are validated under different ambient temperatures and water flow rates. The simulation and experiment results shows acceptable agreement, the maximum difference is respectively 8.9%, 5.9%, 9.5% and 8.2% for engine torque, motor torque, reclaimed heat and fuel-consumed rate. Based on the simulation results, HPGHP has the lowest fuel-consumed rate of 283 g (kWh)⁻¹ at engine speed of 3000 rpm; the PER of HPGHP system is about 15.9% and 11.4% higher than the GHP under the same load in Mode C and D.     

Optimal design of a light commercial freezer through the analysis of the combined effects of capillary tube diameter and refrigerant charge on the performance

In this work, a discussion on a methodology to optimize the performance of a commercial freezer by using a simulation tool is presented. In order to provide a practical tool for deciding the best combination of refrigerant charge and capillary tube diameter, the results of the numerical studies are shown in the form of two-dimensional maps. The usefulness of this type of representation lies in the possibility of selecting the best operating point of the system, taking into account not only the efficiency or the power consumption but also the technical constrictions imposed by parameters such as the suction line temperature, the condenser subcooling, the evaporator superheat, and the run-time ratio. The discussion leads to the conclusion that the useful performance map is drastically reduced when all the operation requirements must be satisfied. Once the system design had been optimized, an additional numerical study, aimed at identifying the influence of the external conditions on the system behavior, was performed. The results show that the performance reduction can be effectively minimized modifying the refrigerant charge.