Hardware Subsystems Research Articles

Design and Application of MMM System for Welding Residual Stress Test

In order to apply metal magnetic memory (MMM) technology to welding residual stress testing, the MMM hardware and software system is designed. The software subsystem is based on object-oriented programming and the hardware subsystem is portable. The MMM system can test the welded joint residual stress distribution, residual stress concentration zones and defects at workshop. Moreover, the MMM testing system can output data to a computer not only for automatic evaluation but also for further analysis and evaluation with expert intervention. According to the trend of the MMM characteristic, the welding residual stress concentration and defects can be detected and evaluated. The field X-ray examination result is consistent with the result of the MMM testing system, which has proved the accuracy and engineering practicality of the MMM testing system.

CODESIGN-ORIENTED AND USER-PERCEIVED SERVICE AVAILABILITY MEASUREMENT FOR HARDWARE/SOFTWARE SYSTEM

Service availability is one of the customer-oriented attribute and defined as the attribute that the system can successfully satisfy the customers' requests. This paper discusses the stochastic service availability measurement for the computer-based system incorporating the concept of hardware/software codesign. We assume that the computer-based system consists of one hardware subsystem and one software subsystem and consider the situation where one customer intermittently uses the system which is operating and available anytime. From the viewpoint of a customer, occurrence of a system failure is recognized when either one of the following two events arises: A system failure occurs when the customer is using the system, or a usage request occurs when the system is down. We propose and derive three kinds of novel service-oriented system availability assessment measure. These are given as the functions of time and the number of software debuggings. The time-dependent behaviors of the system alternating between up and down states and the customer's request are described by a Markov process. Especially for the software subsystem, we incorporate the dynamic software reliability growth process, the upward tendency of difficulty in debugging, and the imperfect debugging environment into the model. Finally, we present several numerical examples of these measures for system service availability analysis.

Dynamic Power Management in Wireless Sensor Networks: State-of-the-Art

In the last few years, interest in wireless sensor networks has increased considerably. These networks can be useful for a large number of applications, including habitat monitoring, structural health monitoring, pipeline monitoring, transportation, precision agriculture, supply chain management, and many more. Typically, a wireless sensor network consists of a large number of simple nodes which operate with exhaustible batteries, unattended. Manual replacement or recharging the batteries is not an easy or desirable task. Hence, how energy is utilized by the various hardware subsystems of individual nodes directly affects the scope and usefulness of the entire network. This paper provides a comprehensive assessment of state-of-the-art of dynamic power management (DPM) in wireless sensor networks. It investigates aspects of power dissipation in a node and analyses the strength and limitations of selective switching, dynamic frequency, and voltage scaling.

VM aware journaling: improving journaling file system performance in virtualization environments

SUMMARYJournaling file systems, which are widely used in modern operating systems, guarantee file system consistency and data integrity by logging file system updates to a journal, which is a reserved space on the storage, before the updates are written to the data storage. Such journal writes increase the write traffic to the storage and thus degrade the file system performance, especially in full data journaling, which logs both metadata and data updates. In this paper, a new journaling approach is proposed to eliminate journal writes in server virtualization environments, which are gaining in popularity in server platforms. Based on reliable hardware subsystems and virtual machine monitor (VMM), the proposed approach eliminates journal writes by retaining journal data (i.e. logged file system updates) in the memory of each virtual machine and ensuring the integrity of these journal data through cooperation between the journaling file systems and the VMM. We implement the proposed approach in Linux ext3 in the Xen virtualization environment. According to the performance results, a performance improvement of up to 50.9journaling approach of ext3 due to journal write elimination. In metadata‐write dominated workloads, this approach could even outperform the metadata journaling approaches of ext3, which do not guarantee data integrity. These results demonstrate that, on virtual servers with reliable VMM and hardware subsystems, the proposed approach is an effective alternative to traditional journaling approaches. Copyright © 2011 John Wiley & Sons, Ltd.

Design of Master Platform of Half-Practicality Maintenance Training System Based on Bus-Mastering

Aming at some shortcomings of maintenance training on actual equipments, it developed half-practicality maintenance training system based on bus-mastering. Among the system, hardware sub-system and control software sub-system design and development of the master platform are key. Basic functions demand was analyzed, on the basis of which main technology indexes was designed. Control software sub-system was designed to include such four parts as control and demonstration, training check and evaluation, comprehensive training, signal flow control and display. Process design of each module of the four parts was implemented. This is significant to innovating equipments maintenance training manners and methods based on virtual reality and bus-mastering technology, and is significant to improving training effectiveness.

Design of Half-Practicality Maintenance Training System Based on Bus-Mastering

With the development and application of all kinds of newest technologies, current weapon equipments are generally complicated integrative systems with mechanical, electrical and liquid su-systems. This makes maintenance training manner and methods be serious problem. So, half-practicality maintenance training system based on bus-mastering will be developed. Complete scheme and overall arrangement were designed based on research about functions of the maintenance training system. It deeply analyzed the need of hardware sub-system and software sub-system of the maintenance training system, on the basis of which one actual equipment system was reconstructed and hardware and software were designed. Reconstruction is mainly used to set faults. It provides guidance to developing half-practicality maintenance training system based on bus-mastering.

High-performance SoC-based implementation of modular exponentiation using evolutionary addition chains for efficient cryptography

Abstract Modular exponentiation is an important operation in several public-key cryptosystems. It is performed using successive modular multiplications. For the sake of efficiency, one needs to reduce the total number of required modular multiplications. This paper brings a novel idea based on the principles of ant colony optimization for finding a minimal addition chain that allows for the reduction of the number of modular multiplications required for modular exponentiations. Furthermore, we propose a hardware/software co-design of a system-on-chip implementation to efficiently compute modular exponentiations. The hardware sub-system implements the modular multiplication, which is the basic and time-consuming operation, while the software sub-system implements the search routine for the adequate operands this multiplication within previously computed products. The ant system is always in execution by an available co-processor, trying to improve the addition chain in use by the overall system. The best addition chain reached by the ant system is compared to the one used in the m-ary and sliding window methods as well as to the best addition chain evolved by genetic algorithms. We demonstrate that the ant system significantly outperforms all these methods for any exponent size. We provide a comparison of the proposed implementation with three existing ones using the performance factor, which takes into account both space and time requirements.

Planckpre-launch status: Design and description of the Low Frequency Instrument

In this paper we present the Low Frequency Instrument (LFI), designed and developed as part of the Planck space mission, the ESA program dedicated to precision imaging of the cosmic microwave background (CMB). Planck-LFI will observe the full sky in intensity and polarisation in three frequency bands centred at 30, 44 and 70 GHz, while higher frequencies (100-850 GHz) will be covered by the HFI instrument. The LFI is an array of microwave radiometers based on state-of-the-art Indium Phosphide cryogenic HEMT amplifiers implemented in a differential system using blackbody loads as reference signals. The front-end is cooled to 20K for optimal sensitivity and the reference loads are cooled to 4K to minimise low frequency noise. We provide an overview of the LFI, discuss the leading scientific requirements and describe the design solutions adopted for the various hardware subsystems. The main drivers of the radiometric, optical and thermal design are discussed, including the stringent requirements on sensitivity, stability, and rejection of systematic effects. Further details on the key instrument units and the results of ground calibration are provided in a set of companion papers.

Advanced LIGO: the next generation of gravitational wave detectors

The Advanced LIGO gravitational wave detectors are next generation instruments which will replace the existing initial LIGO detectors. They are currently being constructed and installed. Advanced LIGO strain sensitivity is designed to be about a factor 10 better than initial LIGO over a broad band and usable to 10 Hz, in contrast to 40 Hz for initial LIGO. This is expected to allow for detections and significant astrophysics in most categories of gravitational waves. To achieve this sensitivity, all hardware subsystems are being replaced with improvements. Designs and expected performance are presented for the seismic isolation, suspensions, optics and laser subsystems. Possible enhancements to Advanced LIGO, either to resolve problems that may arise and/or to allow for improved performance, are now being researched. Some of these enhancements are discussed along with some potential technology being considered for detectors beyond Advanced LIGO.

Three-dimensional computer-controlled acoustic pressure scanning and quantification of focused ultrasound

We propose an automated needle hydrophone-based scanning system to measure high-resolution 3-D acoustic pressure distributions generated by high-intensity focused ultrasound (HIFU). The hardware consists of a host computer, subsystems for HIFU generation, and an oscilloscope to sample the pressure response from a sensor in a water tank. Software was developed to control the hardware subsystems, to search for the initial scan position, and to design the scanning path and volume. A preoperative scanning plan with three perpendicular planes is used to manipulate the position of the HIFU transducer and to automate the acquisition of the spatial acoustic pressure distribution. The post-processing process displays the scanning results, compensates time delays caused by continuous linear scans, and quantifies the focal region. A method to minimize the displacement error induced by the time delay improves the scanning speed of a conventional needle hydrophone-based scanning system. Moreover, a noise-robust, automatic-focus searching algorithm using Gaussian function fitting reduces the total number of iterations and prevents the initial scanning position search from diverging. Finally, the minimum-volume enclosing ellipsoid approximation is used to quantify the size and orientation of the 3-D focal region thresholded by the minimum pressure of interest for various input conditions and to test the reproducibility of the scanning system.

A generic data structure for integrated modelling of tokamak physics and subsystems

The European Integrated Tokamak Modelling Task Force (ITM-TF) is developing a new type of fully modular and flexible integrated tokamak simulator, which will allow a large variety of simulation types. This ambitious goal requires new concepts of data structure and workflow organisation, which are described for the first time in this paper. The backbone of the system is a physics- and workflow-oriented data structure which allows for the deployment of a fully modular and flexible workflow organisation. The data structure is designed to be generic for any tokamak device and can be used to address physics simulation results, experimental data (including description of subsystem hardware) and engineering issues.

Real‐time simulation of electric machine drives with hardware‐in‐the‐loop

Purpose – This paper seeks to present a fully digital, real‐time (RT) hardware‐in‐the‐loop (HIL) simulator on PC‐cluster, of electric systems and drives for research and education purposes; to use the developed system to conduct several motor drives implementation and to evaluate the motor and the control algorithm performance in RT.Design/methodology/approach – This simulator was developed with the aim of meeting the simulation needs of electromechanical drives and power electronics systems while solving the limitations of traditional RT simulators. This simulator has two main subsystems, software and hardware. The two subsystems were coordinated together to achieve the RT simulation. The software subsystem includes MATLAB/Simulink environment, a C++ compiler and RT shell. The hardware subsystem includes FPGA data acquisition card, the control board, the sensors, and the controlled motor.Findings – The complexity of RT implementation of motor drives is greatly reduced by utilizing this simulator. The det...

DynaSPOT: Dynamic Services Provisioned Optical Transport Test-Bed—Achieving Multirate Multiservice Dynamic Provisioning Using Strongly Connected Light-Trail (SLiT) Technology

In this paper, we report on the dynamic services provisioned optical transport (DynaSPOT) test-bed-a next-generation metro ring architecture that facilitates provisioning of emerging services such as Triple Play, Video-on-Demand (VoD), pseudowire edge-to-edge emulation (PWE3), IPTV, and Data Center Storage traffic. The test-bed is based on the recently proposed strongly connected light-trail (SLiT) technology that enables the triple features of dynamic provisioning, spatial subwavelength grooming and optical multicasting-that are quintessential for provisioning of the aforementioned emerging services. SLiT technology entails the use of a bidirectional optical wavelength bus that is time-shared by nodes through an out-of-band control channel. To do so, the nodes in a SLiT exhibit architectural properties that facilitate bus function. These properties at the network side include ability to support the dual signal flow of drop and continue as well as passive add, while at the client side include the ability to store data in order to support time-shared access. The latter (client side) improvisation is done through a new type of transponder card-called the trailponder that provides for (electronic) storage of data and fast transmission (burst-mode) onto the SLiT. Further in order to efficiently provision services over the SLiT, there is a need for an efficient algorithm that facilitates meeting of service requirements. To meet service requirements we propose a dynamic bandwidth allocation algorithm that allocates data time-slots to nodes based on a valuation method. The valuation method is principally based on an auctioning scheme whereby nodes send their valuations (bids) and a controller node responds to bids by sending a grant message. The auctioning occurs in the control layer, out-of-band and ahead in time. The novelty of the algorithm is the ability to take into consideration the dual service requirements of bandwidth request, as well as delay sensitivity. At the hardware level, implementation is complex-as our trailponders are layer-2 devices that have limited service differentiation capability. Here, we propose a dual VLAN tag and GFP-based unique approach that is used for providing service differentiation at layer-2. Another innovation in our test-bed is the ability to support multispeed traffic. While some nodes function at 1 Gb/s, and others function at 2.5 Gb/s (using corresponding receivers), a select few nodes can support both 1- and 2.5-Gb/s operation. This novel multispeed support coalesced with the formerly mentioned multiservice support is a much needed boost for services in the metro networks. We showcase the test-bed and associated results, as well as descriptions of hardware subsystems.

Emulator-based control for actuator-based hardware-in-the-loop testing

Hardware-in-the-loop (HWiL) is a form of component testing where hardware components are linked with software models. In order to test mechanical components an additional transfer system is required to link the software and hardware subsystems. The transfer system typically comprises sensors and actuators and the dynamic effects of these components need to be eliminated to give accurate results. In this paper an emulator-based control strategy is presented for actuator-based HWiL. Emulator-based control can solve the twin problems of stability and fidelity caused by the unwanted transfer system (actuator) dynamics. Significantly EBC can emulate the inverse of a transfer system which is not causally invertible, allowing a wider range of more complex transfer systems to be controlled. A robustness analysis is given and experimental results presented.

OATS: Oxford Aerial Tracking System

Small robot helicopters are becoming a popular research platform due to the availability of off-the-shelf components and their suitability for useful applications. We describe the Oxford Aerial Tracking System (OATS) that we are commissioning, which takes a commercial airframe and low-level flight controller, and adapts these for use in applications requiring the visual tracking of ground targets. This uses a camera on a two-axis gimbal feeding images into an on-board processing system, which communicates summary information to a ground station. So far we have tested the system off the aircraft using laboratory targets and canned image sequences; we have also developed in simulation a variety of high-level algorithms for the platform, including those for target area scanning, geo-localisation, 3-D path planning, and target trajectory prediction; this paper focuses on the hardware, system software, and object tracking sub-systems. Testing on the airframe is now underway.

Redundant I/O interconnect

The outstanding reliability, availability, and serviceability (RAS) characteristics of IBM mainframe computers are among the features that gained the IBM eServer™ family its reputation as a leading platform for business-critical applications. The aim now is to further improve IBM System z9® RAS by introducing redundant I/O interconnect (RII) as a building block of enhanced book availability and recovery scenarios. RII provides a means of maintaining I/O connectivity during planned or unplanned outages in a way that is transparent to the operating system and customer applications. The mechanism that meets this requirement is the provision of an alternate path to the I/O cage, which provides high-bandwidth I/O slots to enable a higher number of I/O ports per card. This paper discusses the I/O subsystem hardware and firmware aspects of RII.

Human redundancy in complex, hazardous systems: A theoretical framework

A theoretical framework is presented to provide a basis for sociotechnical system design strategies to promote effective human redundancy in complex, hazardous systems and to support qualitative human reliability assessment. A concept of human redundancy is proposed, including a description of human redundancy forms. Human redundancy forms constitute the various ways in which human redundancy can be implemented in a sociotechnical system and incorporate human redundancy structures, active and standby human redundancy, duplication and overlap of functions, and cognitive diversity. Multi-modal redundancy structures in systems with human, hardware and software sub-systems are described. The foregoing concept of human redundancy is integrated with an adapted error recovery process. The resulting framework accounts for human redundancy forms, the influence of the nature of the error to be recovered, underlying error recovery processes (initiation of human redundancy followed by detection, indication, explanation and correction of the error), the local and organisational factors influencing the effectiveness of human redundancy, and cognitive diversity. On the basis of this framework, failures of human redundancy are analysed, sociotechnical system design strategies for the promotion of effective human redundancy are discussed, and future research needs are outlined.

Character detection and recognition system of beer bottles

An optical imaging system and a configuration characteristic algorithm are presented to reduce the difficulties in extracting intact characters image with weak contrast, in recognizing characters on fast moving beer bottles. The system consists of a hardware subsystem, including a rotating device, CCD, 16 mm focus lens, a frame grabber card, a penetrating lighting and a computer, and a software subsystem. The software subsystem performs pretreatment, character segmentation and character recognition. In the pretreatment, the original image is filtered with preset threshold to remove isolated spots. Then the horizontal projection and the vertical projection are used respectively to retrieve the character segmentation. Subsequently, the configuration characteristic algorithm is applied to recognize the characters. The experimental results demonstrate that this system can recognize the characters on beer bottles accurately and effectively; the algorithm is proven fast, stable and robust, making it suitable in the industrial environment.

Modelangelo: a subtractive 5-axis robotic arm for rapid prototyping

A PC-based, CAD-driven, 5-axis rapid prototyping (RP) robotic system that uses subtractive technology is presented. ModelAngelo, as it is called, consists of six integrated hardware and software subsystems. The system utilizes a virtual 3D CAD model to produce a set of commands used to control a 5-axis robotic setup to move the cutting tool, the tip of which is a heated wire, into a workpiece block (polystyrene foam or wax) to form complex-shaped objects. The user provides a 3D CAD model of the object to be sculpted. ModelAngelo Software generates layered contoured slices at predetermined incremental steps. It builds up a data file that contains the corresponding cutting tool radial, angular, elevation and rotational positions of the modeled work. Then ModelAngelo PortMessenger feeds the computer parallel port with consecutive commands that are read by ModelAngelo Controller. Consequently, ModelAngelo ReadNFeed performs the commands and sends feedback signals to the processor. The actuators then place the tool tip and the workpiece in their respective cutting positions via ModelAngelo Mechanisms, which puts the model and the tip tool in the cutting position, where ModelAngelo TipTool cutting-by-heat role starts.

Neural Net and Discrete Event Simulations of C2 Performance in Army TOCs

This project examines command and control (C2) from a system level viewpoint to study the way Tactical Operations Centers (TOC's) operate and then translates those observations into validated computer simulations using a methodological framework. This approach provides the ability to model TOC operations in a way that not only includes the individuals, work groups and teams in it, but also all of the other hardware and software systems and subsystems and human-system interfaces that comprise it as well as the facilities and environmental conditions that surround it. Datamining procedures, including neural network simulation, are used to screen raw data from naturalistic observation of TOC operations to identify significant relationships for follow-on analysis. Discrete event simulations then utilize mathematical relationships from the neural network analysis to describe TOC operations in a way that can be used for evaluations of new and proposed TOC Systems. The intent of this project is to develop a framework of techniques and procedures that are based upon empirical methods but are usable in real world, uncontrolled environments which can only be approached with naturalistic observation methods.