91,593 research outputs found

    Virtual ICS test bed

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    Many organizations utilize Building Automation Systems (BAS) to ensure that all the systems in the building are functioning properly, for example their Heating, Ventilation and Air conditioning (HVAC) systems. More advanced versions of these systems, known as Supervisory Control and Data Acquisition (SCADA) systems have been architected to monitor intricate industrial processes and critical energy systems. While some security standards, such as NIST, have been developed, both BAS and SCADA systems are vulnerable to being compromised, especially if they have been networked through the Internet. Compounding the challenge, most of these Industrial Control Systems (ICS) are proprietary, which translates into organizations being unable to test their vulnerability for themselves. The objective of this project was to construct a high-fidelity model of a complex Industrial Control System based on the system currently in place at Iowa State University. This would allow Iowa State an opportunity to test the fortitude of their industrial systems. This project, therefore, was designed to create a functioning virtual model of the systems within two buildings at Iowa State University. Additional constraints on this effort included working within the existing ISERink environment and utilization of OpenPLC, the only known open source PLC tool available at this time. This project successfully created a fully functional virtual model, including: ā€¢ Identification and selection of tools (Modbus Master Simulator and ScadaBR) ā€¢ Configuration of tools ā€¢ Integration of tools ā€¢ Creation of a test data set ā€¢ Connections among the data ā€¢ Generation of alerts for centralized monitoring ā€¢ System testin

    Spacecraft attitude control using a smart control system

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    Traditionally, spacecraft attitude control has been implemented using control loops written in native code for a space hardened processor. The Naval Research Lab has taken this approach during the development of the Attitude Control Electronics (ACE) package. After the system was developed and delivered, NRL decided to explore alternate technologies to accomplish this same task more efficiently. The approach taken by NRL was to implement the ACE control loops using systems technologies. The purpose of this effort was to: (1) research capabilities required of an expert system in processing a classic closed-loop control algorithm; (2) research the development environment required to design and test an embedded expert systems environment; (3) research the complexity of design and development of expert systems versus a conventional approach; and (4) test the resulting systems against the flight acceptance test software for both response and accuracy. Two expert systems were selected to implement the control loops. Criteria used for the selection of the expert systems included that they had to run in both embedded systems and ground based environments. Using two different expert systems allowed a comparison of the real-time capabilities, inferencing capabilities, and the ground-based development environment. The two expert systems chosen for the evaluation were Spacecraft Command Language (SCL), and NEXTPERT Object. SCL is a smart control system produced for the NRL by Interface and Control Systems (ICS). SCL was developed to be used for real-time command, control, and monitoring of a new generation of spacecraft. NEXPERT Object is a commercially available product developed by Neuron Data. Results of the effort were evaluated using the ACE test bed. The ACE test bed had been developed and used to test the original flight hardware and software using simulators and flight-like interfaces. The test bed was used for testing the expert systems in a 'near-flight' environment. The technical approach, the system architecture, the development environments, knowledge base development, and results of this effort are detailed

    Economic analysis of the implementation of autologous transfusion technologies throughout England

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    Objectives: This study aims to provide the first estimates of the costs and effects of the large scale introduction of autologous transfusion technologies into the United Kingdom National Health Service. Methods: A model was constructed to allow disparate data sources to be combined to produce estimates of the scale, costs, and effects of introducing four interventions. The interventions considered were preparing patients for surgery (PPS) clinics, preoperative autologous donation (PAD), intraoperative cell salvage (ICS), and postoperative cell salvage (PoCS). Results: The key determinants of cost per operation are the anticipated level of reductions in blood use, the mean level of blood use, mean length of stay, and the cost of the technology. The results show the potential for considerable reductions in blood use. The greatest reductions are anticipated to be through the use of PPS and ICS. Vascular surgery, transplant surgery, and cardiothoracic surgery appear to be the specialties that will benefit most from the technologies. Conclusions: Several simplifications were used in the production of these estimates; consequently, caution should be used in their interpretation and use. Despite the drawbacks in the methods used in the study, the model shows the scale of the issue, the importance of gathering better data, and the form that data must take. Such preliminary modeling exercises are essential for rational policy development and to direct future research and discussion among stakeholders

    Mixed signal approach for rapid prototyping of a compact smart pebble for sediment transport monitoring in river beds

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    Low-cost accelerometers and gyro ICs were used to develop a smart sediment particle to study the sediment transport in rivers. With strap-down MEMS, battery, a processing subsystem and memory, this self contained unit captures semiprocessed data for durations up to 15 minutes. In a mixed-mode design, analog multiplier ICs with limited digital circuits transform the body frame data to a reference frame using Euler angles, with adequate accuracy despite cumulative errors. For 3D motion, up to nine sensor inputs from three orthogonal modules are coupled to a multiplexed analog processing module, and processed by a digital module for data conversion and storage. Despite the simplified mathematics used, experimental data from the proof-of-concept system provided adequate accuracy. Subsequent processing of the raw sensor data using an external PC program with smart algorithms allowed the comparison of accuracy of the mixed mode approach. The adopted mixed signal design approach helps the packaging requirements due to the specific nature of the problem with short recording durations

    Assessing and augmenting SCADA cyber security: a survey of techniques

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    SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability

    Experimental and computational investigation of a new solar integrated collector storage system

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    The paper discusses a combined experimental-numerical analysis of an innovative solar thermal device to be used as an Integrated Collector Storage (ICS) system providing domestic hot water. In this equipment the collector acts also as a storage unit, without requiring an external vessel. Due to its simple configuration, the ICS device was successfully used in several circumstances, especially in extreme situations such as in post-earthquake tent cities or to reach remote users in Africa. In order to assess the efficiency of this collector, the draw-off process was investigated measuring the value of the mean temperature of the water discharging from the tap as cold water filled the collector. In the present configuration the draw-off is not completely optimised and a detailed analysis was carried out in order to investigate the mixing of cold and hot water in the solar collector during the discharge phase. A series of thermocouples was placed in selected positions around the shield of the collector to investigate the evolution of the near wall temperature. Furthermore, a numerical analysis based on Large-Eddy Simulation (LES) of the mixing process inside the collector was carried out using an open source, in-house, finite-volume computational code. Even if some restrictive hypotheses were made on the thermal boundary conditions and the absence of stratification, the LES results gave interesting findings to improve the collector performance

    Beating heart coronary surgery and renal function: a prospective randomised study (Presented at 18th Spring Meeting of the Association of Cardiothoracic Anaesthetists: Selected abstracts, Cambridge, UK. 22 June 2001)

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    Introduction Cardiopulmonary bypass (CPB) is widely regarded as an important contributor to renal failure, a well recognised complication, following coronary artery surgery (CABG). Off-pump coronary surgery (OPCAB) is intuitively considered renoprotective. We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass (ONCAB).Methods Forty patients awaiting elective CABG were prospectively randomized into those undergoing OPCAB (n = 20) and ONCAB (n = 20). Table 1 illustrates the exclusion criteria. Glomerular and tubular injury were assessed, respectively, by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to urinary creatinine [1]. Daily measurements were made from admission to postoperative day 5. Fluid balance, serum creati-nine and blood urea were also monitored. Results No mortality or renal complication was observed. Both groups had similar demographic make-up. The OPCAB group received fewer coronary grafts than their counterparts (1.8 versus 2.8; P = 0.002). Serum creatinine and blood urea remained normal in both groups throughout the study. A dramatic and similar rise in mean Ā± 2SD urinary RBP:creatinine ratio occurred in both groups peaking on day 1 (3183 Ā± 2534 versus 4035 Ā± 4078; P = 0.43) before returning to baseline levels. These trends were also observed with the urinary microalbumin:creatinine ratio (5.05 Ā± 2.66 versus 6.77 Ā± 5.76; P = 0.22). ONCAB patients had a significantly more negative fluid balance on postoperative day 2 (-183 Ā± 1118 versus 637 Ā± 847 ml; P < 0.05). Conclusions Although renal dysfunction did not clinically occur in any patient, sensitive indicators revealed significant and similar injury to both renal tubules and glomeruli following either OPCAB or ONCAB. These suggest that avoidance of CPB per se does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG

    Factors affecting the sleep of one-year-olds : a pilot study using objective monitoring of New Zealand infants : a thesis presented in partial fulfilment of the requirements of the degree of Master of Science in Psychology at Massey University, Wellington, New Zealand

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    Sleep takes time to mature and in infancy the structure and cycle of sleep differs greatly to that of adults. Data concerning normative sleep of infants is lacking due to few studies using objective measures. Factors affecting infants' sleep are both intrinsic and extrinsic in nature. The causes of problematic sleep are not well understood. This study aimed to pilot a methodology involving 1 week of actigraphy monitoring of 1-year-olds, as well as collecting normative data concerning sleep and sleep ecology through questionnaires and diaries. Potential factors contributing to sleep quantity, quality and maturation were investigated. Sleeping problems were reported in 35% of the sample of 52 Wellington infants. Current breastfeeding, time awake at night, and poor evening mood were all associated with problem sleep. Short sleep duration and more instances of being put to bed were also significant predictors of reporting problem sleep. Infants were typically rated in a poorer mood and exhibited more bedtime problems at the weekend. Longer sleep onset latencies and poorer sleep efficiency were identified by actigraphy on weekend evenings. The timing of sleep did not differ between genders or between week days and weekends, or childcare and non-childcare days. Mixed model analysis of variance indicated that the maturation and quality of sleep were significantly correlated with age and stages of cognitive and motor development. Sleep duration did not correlate with ponderal index, possibly due to the young age group as well as underrepresentation of short sleeping or overweight infants. Results support previous studies in western societies and autonomous sleeping is common. Potential mechanisms behind relationships between sleep and feeding, temperament and development are discussed. Strengths and limitations of methods and procedures are assessed. Actigraphic recording of 1-year-olds is demonstrated to be a useful and reliable tool for studying sleep of infants and the results contribute to normative data. Future studies in NZ should consider recruiting a more representative sample and incorporate a longitudinal design to further assess the relationships highlighted here and in previous research
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