Towards a verifiable real-time, autonomic, fault mitigation framework for large scale real-time systems

Designing autonomic fault responses is difficult, particularly in large-scale systems, as there is no single ‘perfect’ fault mitigation response to a given failure. The design of appropriate mitigation actions depend upon the goals and state of the application and environment. Strict time deadlines in real-time systems further exacerbate this problem. Any autonomic behavior in such systems must not only be functionally correct but should also conform to properties of liveness, safety and bounded time responsiveness. This paper details a real-time fault-tolerant framework, which uses a reflex and healing architecture to provide fault mitigation capabilities for large-scale real-time systems. At the heart of this architecture is a real-time reflex engine, which has a state-based failure management logic that can respond to both event- and time-based triggers. We also present a semantic domain for verifying properties of systems, which use this framework of real-time reflex engines. Lastly, a case study, which examines the details of such an approach, is presented.     

Mobile information services enabled by mobile publishing (MIS-MP)

Mobile users and devices want to discover and share a growing range of information as the processing and storage capabilities of mobile devices grow. For example, users want to discover nearby networks, and location-based or time-sensitive user information contents. A mobile device may want to discover neighboring networks and the parameters required to access these networks so that it can intelligently decide which networks to use next, and use its existing network connection to authenticate with selected neighboring networks before it moves into the coverage areas of the selected networks. This can significantly reduce handoff delays. Existing service discovery frameworks are not effective for such neighboring network discovery or for discovering dynamic, location- or time-sensitive user information contents. This paper describes and evaluates a new approach—Mobile Information Services enabled by Mobile Publishing (MIS-MP)—for real time collection, discovery, and sharing of network and user information. With MIS-MP, mobiles take full advantage of the wealth of information they can accumulate during their routine mobility and use of networks to help each other to discover the information they want when and where they want it. This is accomplished by mobiles publishing the information they collect about the networks they visited, and the user information contents they learned or used, to make the information available to other mobiles. This paper presents analytical models and simulation results to evaluate the feasibility and performance of MIS-MP. It also describes a testbed implementation of MIS-MP and some of the lessons we learned. Tao Zhang is Director of Mobile Networking Research Group at Telcordia Technologies, Piscataway, New Jersey, USA. He develops and directs research and advanced development programs in mobile networking and applications, including mobility and applications across heterogeneous radio networks, mobile information services, vehicular networking, mobile peer-to-peer applications, sensor networking and applications, and collaborative networking .Dr. Zhang’s work has led to several new commercial products. He co-authored the book “IP-Based Next Generation Wireless Networks” published by John Wiley & Sons in 2004. He initiated the International Conference on Collaborative Computing: Networking, Applications, and Worksharing (CollaborateCom), and has been serving in various roles for it. Dr. Zhang holds 4 U.S. patents, with over 25 more pending. He received the 2000 Telcordia CEO Award (for most exceptional teams and individuals who have achieved a significant business success) and 2002 SAIC’s Executive Science and Technology Council Publication Prize. Eric van den Berg received his Ph.D. in Applied Mathematics from Cornell University in 1999. After obtaining his degree, he joined Telcordia Technologies, where he is a Research Scientist in Applied Research Department. His research interests include traffic modeling and performance analysis of IP- and wireless networks. He received the 2000 Telcordia CEO Award (for most exceptional individuals and teams who have achieved a significant business success) and the 2002 SAIC Executive Science and Technology Council Publication Prize. Sunil Madhani is a Distinguished MTS with Motorola where he manages the IP Realization team in Mobile Device Technology Office. He aims at working on unconventional and disruptive IP technologies. His current research focus is on convergent networks, dynamic mobility management and fast handoff in secured/seamless wireless LAN/WAN roaming. His past research includes registration/configuration protocols in wireless environment, application layer mobility management, secured Mobile IP, managed DOS attack sensor and TCP/IP boosters. Sunil Madhani holds MS (2002) in Engineering Management & System from Columbia University and MS (1997) in Computer Science from State University of New York.     

Evaluation of satellite-altimetry-derived river stage variation for the braided Brahmaputra River

In this study, river stage variation derived from satellite altimetry was used to assess the water level, monthly discharge, and annual water yield at six virtual gauging stations at the braided reaches of the Brahmaputra River. The braided reaches of the river dynamically change their planform, thalweg line, and aggradation or degradation period. Stage records derived from the Envisat satellite of the European Space Agency and Topex/Poseidon of NASA/CNES were used for the period 2002–2010. Spatial interpolation and datum correction were applied on altimetry-derived river stage records before analysis. A correlation and error analysis between the in situ and satellite-altimetry-derived stages was carried out for these stations for both monsoon and non-monsoon seasons. Yearly optical satellite images were used for qualitative assessment of temporal variations in aggradation/degradation phases at the gauging stations. Using the pseudo-rating curve, discharges at two virtual gauging stations were estimated. The results show that the altimetry-estimated discharges are of good agreement with observed discharge for the monsoon months (June–September) as compared with the non-monsoon months (October–May). In order to assess the annual water yield variability, yearly variation in annual water yield from the altimetry data was also estimated and compared to that observed. The estimated annual water yields were 90% accurate. Similarly, the long-term averaged monthly discharge series estimated from satellite altimetry closely follows the temporal trend of that of the observed series.     

Indigenous design and development of a micro-pulse lidar for atmospheric studies

A sophisticated micro-pulse lidar (MPL) has been designed and developed for the study of the atmospheric boundary layer (ABL) and clouds. The developed MPL uses a low energy pico-second pulsed Nd:YAG laser at 532 nm. The conventional receiver optic is used along with a photomultiplier tube in single photon detection mode. Stanford Research Systems' multi-channel scalar (MCS) is used with a personal computer for data acquisition. Due to the short laser pulse and a fast MCS, a spatial resolution of 0.75 m has been achieved. The control circuit has been designed to sense telescope cover status (open or closed) to avoid any mistakes in dark count and background data acquisition. The complete control software and Graphical User Interface (GUI) has been developed in Visual Basic. The lidar system has been tested both for its functionality to detect the variation in ABL and cloud height and also for its capability to acquire continuous night-time data without user interaction. In this article the design details and some preliminary results are discussed.     

Tropospheric ozone variability over the Indian coastline and adjacent land and sea

A tropospheric ozone variability study is carried out to investigate the spatial and temporal distribution over the coastline of the Indian peninsula and adjacent land and sea using NASA Langley Tropospheric Ozone Residual data set for the period 1979–2005. A strong seasonal cycle has been observed with large variation (～ 55%) over the upper eastern coast, followed by the upper and lower western coast, compared to the lower eastern coast (～ 33%). A negative gradient in ozone concentration is observed along eastern and western coasts during summer (slope ～ –0.78 and –0.65) and a positive gradient (slope ～ 0.16 and 0.21) during winter. The same is observed over the adjacent land and sea along the coastline with slight variation. This change in gradient can be attributed to the anthropogenic emission of precursor gases that reinforce localized photochemical production of ozone. In addition, topography, transport, seasonality of emission of precursor gases and the solar insolation cycle play a vital role.     

Structural,morphological and microhardness characterization in polymer complex of laser dye rhodamine (Rh6G) doped polymethyl methacrylate

Polymer systems have various contents of rhodamine (Rh6G) doped Polymethyl methacrylate (PMMA) prepared by solution cast method. The structural and morphological properties were studied by Differential Scanning calorimetry (DSC), Fourier Transform Infrared spectroscopy (FTIR) Scanning Electron Microscopy (SEM) and X-ray diffraction methods. The induced effect on the strength of rhodamine (Rh6G) doped Polymethyl methacrylate (PMMA) samples were studied by measuring the surface microhardness using the Vicker’s microhardness tester. Significant changes were observed in the Vickers microhardness number (H_v)     

Cooling of roll and strip in steel rolling

Adequate cooling of the roll and strip is of considerable importance for mill designers, process engineers, and consumers. The purpose of this paper is to review recent heat-transfer research of the cooling technology in the steel-rolling process. The importance of roll and strip cooling on the thermomechanical treatment will be discussed with an assessment of the research on the corresponding heat-transfer coefficients for various cooling systems currently used. Special laboratory apparatus resembling the cooling system used in steel mills has been developed to study the major parameters that control the cooling processes. Since the heat-transfer coefficient is the most important indicator of the effectiveness of a cooling system, the coefficient under various roll-cooling conditions is experimentally studied by the special apparatus and numerically evaluated by a finite difference technique.     

Detection schemes for space-time block code and spatial multiplexing combined system

Space-time block code is combined with spatial multiplexing technique over multiple-input multiple-output system to take advantages of both schemes. The transmit antennas are divided into groups and each group transmits space-time coded blocks in parallel. At receiver side, three types of group receivers are proposed to separate the filtered version of the multiplexed space-time coded symbol blocks followed by space-time decoder. Error rate performances of the detection schemes are evaluated in correlated channels. The diversity order of the combined system is compared with that of the SM system and the STBC system.     

Laser beam machining—A review

Laser beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. Laser beam is focussed for melting and vaporizing the unwanted material from the parent material. It is suitable for geometrically complex profile cutting and making miniature holes in sheetmetal. Among various type of lasers used for machining in industries, CO₂ and Nd:YAG lasers are most established. In recent years, researchers have explored a number of ways to improve the LBM process performance by analysing the different factors that affect the quality characteristics. The experimental and theoretical studies show that process performance can be improved considerably by proper selection of laser parameters, material parameters and operating parameters. This paper reviews the research work carried out so far in the area of LBM of different materials and shapes. It reports about the experimental and theoretical studies of LBM to improve the process performance. Several modelling and optimization techniques for the determination of optimum laser beam cutting condition have been critically examined. The last part of this paper discusses the LBM developments and outlines the trend for future research.     

A new generic multistep power control algorithm for the LEOsatellite channel with high dynamics

LEO satellite CDMA systems, characterized by round-trip delay and high variation in slow fading, call for different considerations on power control algorithms. Based on the criteria of fast response, small over-compensation, oscillation-avoiding and minimum power control error, the transient behavior of the fixed step, adaptive step, and multistep power control algorithms are investigated and compared. A new generic multistep power control algorithm with excellent dynamic performance is proposed for LEO satellite systems