一种两相流浓度测量传感器的仿真研究

在石油,化工等诸多生产领域的生产过程中,两相流各种参数的在线实时测量与控制是生产稳定可靠运行的重要保证,其中相浓度就是一项十分重要的参数;为了避免电容传感器结构对相浓度的影响,设计了一种同轴电容传感器,利用有限元分析软件ANSYS 对其进行了分析,在不同浓度相同流型及相同浓度不同流型两种实验方案下进行了大量实验;结果表明,该结构传感器具有均匀的敏感场分布和较高的灵敏度,而且该结构传感器电容值与流型无关,只与浓度变化有关;因此该结构传感器可应用于气/液、液/液两相流浓度参数检测,具有广阔的应用前景.     

应用型本科计算机专业实践教学体系的构建与实施

分析应用型本科计算机专业实践教学体系及其实施过程中存在的不足,提出构建培养应用型人才的"基本操作"、"硬件应用"、"算法分析与程序设计"、"系统综合开发"四种专业能力的实践教学体系,并介绍了具体途径、方法及实施效果。     

Attribute-based on-demand multicast group setup with membership anonymity

In many applications, it is desired to dynamically establish temporary multicast groups for secure message delivery. It is also often the case that the group membership information itself is sensitive and needs to be well protected. However, existing solutions either fail to address the issue of membership anonymity or do not scale well for dynamically established groups. In this paper, we propose a highly scalable solution for dynamical multicast group setup with group membership anonymity. In the proposed solution, scalability and membership anonymity are achieved via a novel design that integrates techniques such as ciphertext-policy attribute-based encryption (CP-ABE). In our design, multicast groups are specified through group member attributes. As these attributes are potentially able to be shared by unlimited number of group members, our proposed scheme scales well. Also, high level of membership anonymity is guaranteed such that every group member knows nothing but his own group membership only. The complexity of our proposed scheme in terms of computational overhead and ciphertext size is O(n), where n is the number of attributes and independent to the group size.     

A Monte Carlo Simulation approach for the modeling of free-molecule squeeze-film damping of flexible microresonators

Squeeze-film damping on microresonators is a significant damping source even when the surrounding gas is highly rarefied. This article presents a general modeling approach based on Monte Carlo (MC) simulations for the prediction of squeeze-film damping on resonators in the free-molecule regime. The generality of the approach is demonstrated in its capability of simulating resonators of any shape and with any accommodation coefficient. The approach is validated using both the analytical results of the free-space damping and the experimental data of the squeeze-film damping on a clamped–clamped plate resonator oscillating at its first flexure mode. The effect of oscillation modes on the quality factor of the resonator has also been studied and semi-analytical approximate models for the squeeze-film damping with diffuse collisions have been developed.     

虚拟式语音信号实时采集与识别平台

提出了基于LabVIEW和MATLAB混合编程的虚拟式语音信号采集、分析与识别平台设计方案;该平台通过PC机声卡完成对语音信号的实时采集和回放,并对语音信号进行时频分析、端点检测和倒谱分析,进而实现语音识别;为提高识别的正确性和灵活性,提出孤立字列举识别算法和词库编码连续语音识别算法;结果表明,两种算法都能有效识别同音字和读音相似的字;其中,词库编码识别算法不仅效率高,还具有一定的纠错能力,更具有应用价值.     

User-input driven QoS management in ad hoc networks

Though the network quality-of-service (QoS) metrics are defined in terms of technical parameters (e.g., delay, jitter, bandwidth), they are rather subjective when it comes to the end user. Oftentimes, the end user finds it difficult to express his desired QoS in such technical parameters, though he has a fair idea of what QoS he desires. In this paper, we show how translation functions can be devised and used to translate the user inputs to networking parameters that are used by various layers of the protocol stack. In particular, we consider an ad hoc network and show an interface design that uses translation functions to map user supplied inputs to parameters at the medium access control (MAC) and routing layers. These parameters, in turn, choose the right strategies that particular layer functionality can adopt, such that the QoS desired by the user is achieved. We also compute the associated costs due to the different strategies adopted. We implement the interface on ns-2 and conduct simulation experiments with randomly scattered IEEE 802.11 enabled nodes. Results show the functionality of the interface and demonstrate how delay, throughput, and network lifetime are affected when the end user seeks different levels of QoS.     

A simple robust control for global asymptotic position stabilization of underactuated surface vessels

Global asymptotic stabilization of underactuated surface vessels is generally achieved only by designing complicated controllers. This paper proposes a very simple control law that globally asymptotically stabilizes the position of underactuated surface vessel to a desired constant location and its velocities to zero. The proposed controller is independent of velocity signals and is robust to model parameters. It neither includes an observer nor an adaptive/sliding‐mode law. Controller development and stability analysis rely on a novel Lyapunov function and LaSalle's theorem. Furthermore, by extending the proposed control strategy, a saturated control law is also obtained ensuring the semiglobal asymptotic stability of position error system. Effectiveness of the proposed control schemes is demonstrated by simulation examples. Copyright © 2017 John Wiley & Sons, Ltd.     

基于PowerDesigner的网络管理数据库设计

网络管理系统以数据为中心,数据库在网络管理中起着至关重要的作用。首先对网络管理系统进行了需求分析,然后利用PowerDesigner设计并实现了网络管理系统数据库,对网络管理系统数据库的开发有一定的借鉴作用。     

封闭式高压开关柜运行环境模糊监控系统的探讨

本文介绍济钢的中置式封闭开关柜运行环境监控系统，解决了因为没有先进有效的监控手段，避免了封闭开关柜因为通风散热差而引起设备事故的发生。     

基于NDIS中间层即时通监控的研究与实现

即时通为人们带来便捷的同时也存在安全方面的问题。该文针对目前即时通的应用现状，分析了即时通的通信模式和协议，结合Windows平台内核态下的NDIS中间层技术实现了对主流即时通文本聊天内容的监控。测试结果表明，系统在实现有效监控的同时，保证了即时通的安全性。