基于模块计算机的千兆网磁共振谱仪控制接口

提出了一个基于模块计算机的磁共振谱仪的控制接口,它建立了核磁共振成像谱仪与上位计算机之间的通信,实现了控制谱仪、上传和下载、数据处理等功能,具备较高的传输速度,以及较好的实时性. 该接口以硬件模块的方式集成到谱仪上,通过千兆和百兆以太网连接上位机,接收下传至谱仪的序列;用中断机制和直接内存存取(DMA)方式实现与谱仪的数据传输,并将处理采集到的回波数据并上传到上位机. 控制接口的设计采用模块计算机Computer-On-Module(COM)的设计思路,以高性能的处理器为嵌入式平台,在Linux操作系统下开发驱动程序和应用程序. 实验证明,该模块具有数据处理速度快、传输速率高,成本低,体积紧凑,扩展性强等特点,是实现磁共振谱仪高性能的控制接口的理想方案.     

四频差动激光陀螺最佳工作点实时控制技术

为了降低四频差动激光陀螺（FMDLG）零偏对外界因素影响的敏感性,采用了最佳工作点实时控制技术。该技术使用色散平衡和稳频偏置的方法,对增益区磁场和失谐频率进行小幅度正弦调制,在FMDLG输出零偏中解调出误差信号,经负反馈控制回路使FMDLG在对外界干扰敏感性最小的唯一最佳工作点下工作。与仅使用光强差进行稳频的传统方法相比,最佳工作点控制技术大大降低了FMDLG的磁敏感度和零偏稳定性,证实了FMDLG最佳工作点实时控制技术的有效性;静态、动态测试实验结果证明了该技术的正确性。     

A survey on analysis and implementation of state-of-the-art haze removal techniques

Haze is a poor-quality state described by the opalescent appearance of the atmosphere which reduces the visibility. It is caused by high concentrations of atmospheric air pollutants, such as dust, smoke and other particles that scatter and absorb sunlight. The poor visibility can result in the failure of multiple computer vision applications such as smart transport systems, image processing, object detection, surveillance etc. One of the major issues in the field of image processing is the restoration of images that are corrupted due to different degradations. Typically, the images or videos captured in the outside environment have low contrast, colour fade and restricted visibility due to suspended particles of the atmosphere that directly influence the image quality. This can cause difficulty in identifying the objects in the captured hazy images or frames. To address this problem, several image dehazing techniques have been developed in the literature, each of which has its own advantages and limitations, but effective image restoration remains a challenging task. In recent times, various learning (Machine learning & Deep learning) based methods greatly condensed the drawbacks of manual design of haze related features and reduces the difficulty in efficient restoration of images with less computational time and cost. The current state-of-the-art methods for haze free images, mainly from the last decade, are thoroughly examined in this survey. Moreover, this paper systematically summarizes the hardware implementations of various haze removal methods in real time. It is with the hope that this current survey acts as a reference for researchers in this scientific area and to provide a direction for future improvements based on current achievements.     

Gait event detection algorithm based on smart insoles

Gait analysis is an effective clinical tool across a wide range of applications. Recently, inertial measurement units have been extensively utilized for gait analysis. Effective gait analyses require good estimates of heel‐strike and toe‐off events. Previous studies have focused on the effective device position and type of triaxis direction to detect gait events. This study proposes an effective heel‐strike and toe‐off detection algorithm using a smart insole with inertial measurement units. This method detects heel‐strike and toe‐off events through a time‐frequency analysis by limiting the range. To assess its performance, gait data for seven healthy male subjects during walking and running were acquired. The proposed heel‐strike and toe‐off detection algorithm yielded the largest error of 0.03 seconds for running toe‐off events, and an average of 0–0.01 seconds for other gait tests. Novel gait analyses could be conducted without suffering from space limitations because gait parameters such as the cadence, stance phase time, swing phase time, single‐support time, and double‐support time can all be estimated using the proposed heel‐strike and toe‐off detection algorithm.     

Novel method for transferring access control list rules to synchronize security protection in a locator/identifier separation protocol environment with cross‐segment host mobility

Extended access control lists (ACLs) are used to filter packets for network security. However, in current network frameworks, ACL rules are not transferred simultaneously with devices that move across network segments. The Internet Engineering Task Force proposed the Locator/Identifier Separation Protocol (LISP), which enables routers (xTRs) to configure ACL rules for blocking immobile endpoint identifiers (EIDs). However, when an EID moves from the original xTR to a new xTR, the ACL rules at the original xTR cannot be transferred with the EID. Thus, the new xTR lacks the corresponding ACL rules to effectively block the EID, resulting in security risks. The highlights of this study are as follows. First, a method is proposed for dynamically transferring ACL rules in LISP environments and frameworks. Second, the map‐register and map‐notify protocols were combined to encapsulate and transfer the ACL rules and thus obviate an additional process required to transfer these rules. Third, the experimental results verified that the proposed method can be used to achieve synchronized security protection in an LISP environment involving cross‐segment EID movements.     

Smart gateways switching control algorithms based on tropospheric propagation forecasts

The use Q/V band spectrum for the feeder links of high throughput satellites and the need to cope with the significant propagation impairments at those frequencies motivate the development of smart diversity techniques. Those techniques aim at improving the availability level of the overall feeder link with a limited level of redundancy. The combinatorial gain of availability provided by those techniques can be obtained only if efficient switching methodologies are developed, performing the best trade‐off between system flexibility and channel prediction accuracy. This paper proposes various propagation forecast mechanisms for the control of switching between gateways in smart diversity, corresponding to various system assumptions in terms of required anticipation time for the triggering of the switches. The performances of those algorithms are then assessed against measured attenuation and meteorological data. It enables to evaluate the performance degradation regarding an idealized case.     

A cross-layer design: energy efficient multilevel dynamic feedback scheduling in wireless sensor networks using deadline aware active time quantum for environmental monitoring

Recently, Packet scheduling plays a vital role in Wireless Sensor Networks (WSNs). The major key challenges include delay, packet dropping, energy consumption and lifetime due to constraints in energy and computing resources. All the research works on packet scheduling scheme in WSN uses only First Come First Served (FCFS) and Dynamic Multilevel Priority (DMP) schemes. FCFS works based on packet arrival time, it leads to starvation and high processing overhead for real-time packets. DMP works in multilevel with dynamic priority reduces the transmission overhead and bandwidth; it consumes more resources for real-time task leads to deadlock. To solve these problems, this work presents Multilevel Dynamic Feedback Scheduling (MDFS) algorithm. The sensor node classifies the emergency and normal data into three different ready queues named as high, medium and low priority, respectively. The queues are connected with a feedback mechanism; each packet from the sensor node has its own time quantum value based on the deadline. The updated time quantum value is compared with the boundary value of the queues, depends on the updated value the data packets are moved between queues with help of feedback mechanism. The simulation result proves that the projected MDFS outperforms in WSN environment.     

Design of 24 GHz Radar with Subspace‐Based Digital Beam Forming for ACC Stop‐and‐Go System

For an adaptive cruise control (ACC) stop‐and‐go system in automotive applications, three radar sensors are needed because two 24 GHz short range radars are used for object detection in an adjacent lane, and one 77 GHz long‐range radar is used for object detection in the center lane. In this letter, we propose a single sensor‐based 24 GHz radar with a detection capability of up to 150 m and ±30° for an ACC stop‐and‐go system. The developed radar is highly integrated with a high gain patch antenna, four channel receivers with GaAs RF ICs, and back‐end processing board with subspace based digital beam forming algorithm.     

An application of univariate marginal distribution algorithm in MIMO communication systems

The paper discusses a sequence detector based on univariate marginal distribution algorithm (UMDA) that jointly estimates the symbols transmitted in a multiple input multiple output (MIMO) communication system. While an optimal maximum likelihood detection using an exhaustive search method is prohibitively complex, it has been shown that sphere decoder (SD) achieves the optimal bit error rate (BER) performance with polynomial time complexity for smaller array sizes. However, the worst‐case complexity of SD is exponential in the problem dimensions, this brings in question its practical implementation for larger number of spatial layers and for higher‐order signal constellation. The proposed detector shows promising results for this overly difficult and complicated operating environment, confirmed through simulation results. A performance comparison of the UMDA detector with SD is presented for higher‐order complex MIMO architectures with limited average transmit power. The proposed detector achieves substantial performance gain for higher‐order systems attaining a near optimal BER performance with reduced computational complexity as compared with SD. Copyright © 2009 John Wiley & Sons, Ltd.     

Sol－Gel法制备的CoMnNiMgO热敏元件老化特性的研究

假设老化是从亚稳态到稳态的变化，利用反应动力学理论对Ｓｏｌ－Ｇｅｌ法制备的ＣｏＭｎＮｉＭｇＯ热敏元件的老化特性进行了研究，推导出老化公式△Ｒ／Ｒｏ＝Σｒｉ［１－ｅｘｐ（－ｔ／τｉ）］其中：τｉ＝τｏｉｅｘｐ（Ｅｉ／ｋＴ））。结果表明理论与实验能很好地一致，对于本文所研究的热敏元件，符合公式ＡＲ／Ｒｏ＝ｒ１［１－ｅｘｐ（－ｔ／τ１）］＋ｒ２［１－ｅｘｐ（－ｔ／τ２）］，该式中：，ｒ１＝１１．７６７×１０－３；ｒ２＝２０．６７３５×１０－３；τ１＝６．４５７８×１０－３ｅｘｐ（６１９０．８９／Ｔ）；τ２＝１．０４６１×１０－６ｅｘｐ（８ｌｌ６．２４／Ｔ）。