Dissertations / Theses: 'Critical control'

1

Misner, Scottie, and Carol Curtis. "HACCP - Hazard Analysis Critical Control Points." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/146434.

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1p.
HACCP, pronounced has-up, is a food safety self-inspection system that combines up-to-date technical information with step-by-step procedures to evaluate and monitor the flow of food throughout a food establishment from receiving to service. This publication introduces this system to readers and outlines 6 simple HACCP principles to reduce the occurrence of food-borne illness at home.

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Åkerberg, Johan. "On Security in Safety-Critical Process Control." Licentiate thesis, Mälardalen University, School of Innovation, Design and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-7334.

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This Licentiate thesis is about security in automation networks with emphasis on fieldbus communication. In the process industry, network and system security have become even more important since the introduction of Ethernet-based fieldbus protocols. As an example, a successful attack on a power plant, supporting large cities with energy, could result in a temporal but total power loss. Such attacks could be devastating for the society. The security threats are real, and motivations for attacking industrial communication systems may be political or economical.

The visions of autonomous systems, which can be supervised, diagnosed and maintained from remote is not far from reality, but stress the need for security and safety measures. Wired fieldbus protocols are mature when it comes to safety and there are existing standards for safe communication. In a setup like an autonomous system security measures over safe communication has to be taken into account.

The state-of-the-art in automation security is to use firewalls to restrict incoming and outgoing traffic to the networks. Firewalls can be deployed between different automation networks, i.e. server, control, and fieldbus networks, and even protect a single automation cell with a dedicated firewall. If an adversary can penetrate the perimeter defenses, no other security countermeasures exist in process automation to protect the safety-critical communication from sabotage.

In this thesis we initially explore the possibilities of security attacks on the automation protocols PROFINET IO and PROFIsafe. We show that it is possible to attack safety-related communication to take control of safety-critical fieldbus nodes. We propose the concept of Security Modules in combination with PROFINET IO and PROFIsafe to achieve safe and secure real-time fieldbus communication.

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Ifill, Wilson. "B annotations in critical control systems development." Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/842966/.

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The design and implementation of critical controllers benefit from development in a formal method such as B. However, B does not support execution specification directly, which is a requirement in controller design. The aim here is to develop a set of annotations so that they can be used by a B design engineer to capture execution requirements, while creating the B model. The annotations, once shown to be machine-annotation consistent with the B machine, can be used independently from the machine to assess the correctness of CSP controllers developed to detail the control behaviour. CSP-B is a formal method integration that can be used to develop critical controller with both state and event behaviour. The advantages of using annotations is that the execution requirements can be captured and shown to be machine-annotation consistent during state operation development, and that a control loop invariant does not have to be independently developed. Handel-C is used on route to hardware synthesis as it supports the implementation of concurrency and the manipulation of state. Annotations are utilised again to guide the translation of the B and control annotations into Handel-C. This PhD. work has three main aims. Firstly, to introduce a set of annotations to describe control directives to permit controller development in B. The annotations capture execution requirements. They give rise to proof obligations that when discharged prove that the annotations are machine-annotation consistent with the machine they are written in, and therefore will not cause the machine to diverge. Secondly, we have proven that CSP controllers that are consistent with the annotations will preserve the non-divergence property established between the machine and the annotations. Thirdly, we show how annotation refinement is possible, and show a range of mappings from the annotated B and the consistent controller to Handel-C. The development of mappings demonstrates the feasibility of automatic translation of annotated B to Handel-C.

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Binnie, Iona B. "Critical dimension control : influencing factors and measurement." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/10815.

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Advanced Lithography continues to be the limiting factor in the drive for higher levels of microcircuit integration. The key to the successful management of a lithography process is the integration of full measurement and instrumentation functions with the process, and the adoption of effective process control strategies. The aim of this research is to improve the understanding of critical dimension (CD) control by an investigation of the sources of variations in linewidth dimensions. Having identified the key factors, it should be possible to characterize and control their influence. Experimental analysis suggests that film thickness and photoresist thickness have a profound effect on linewidth dimensions. Simulation techniques are used to establish a theory which uses standing wave patterns within film stacks to predict reflectance and exposure threshold, as well as the dimensions of the developed resist images. This theory is later corroborated by measurements on test wafers. Having established the need to monitor film thickness variations, a novel metrology technique which incorporates both film thickness and linewidth uniformity measurements is introduced. The technique is based on the optical characteristics of a 'chequerboard' test pattern, consisting of clear and opaque squares. The chequerboard effectively enhances deviations in CD by translating changes in linewidth into an area change on the chequerboard. The technique was originally based on the measurement of light transmitted through glass wafers. The implementation of the technique using reflectance from silicon wafers is described, and possible future developments of the system are discussed.

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Åkerberg, Johan. "On security in safety-critical process control /." Västerås : School of Innovation, Design and Engineering, Mälardalen University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-7334.

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Venugopalan, Vigneshwaran. "Supervisory wireless control for critical industrial applications." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/8501/.

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7

Dawson, Robert Edward. "Secure communications for critical infrastructure control systems." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20710/1/Robert_Dawson_Thesis.pdf.

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In March 2000, 1 million litres of raw sewage was released into the water system of Maroochy Shire on Queensland’s sunshine coast. This environmental disaster was caused by a disgruntled ex-contractor using a radio transmitter to illicitly access the electronically controlled pumps in the control system. In 2007 CNN screened video footage of an experimental attack against a electrical generator. The attack caused the generator to shake and smoke, visually showing the damage caused by cyber attack. These attacks highlight the importance of securing the control systems which our critical infrastructures depend on. This thesis addresses securing control systems, focusing on securing the communications for supervisory control and data acquisition (SCADA) systems. We review the architectures of SCADA systems and produce a list of the system constraints that relate to securing these systems. With these constraints in mind, we survey both the existing work in information and SCADA security, observing the need to investigate further the problem of secure communications for SCADA systems. We then present risk modelling techniques, and model the risk in a simple SCADA system, using the ISM, a software tool for modelling information security risk. In modelling the risk, we verify the hypothesis that securing the communications channel is an essential part of an effective security strategy for SCADA systems. After looking at risk modelling, and establishing the value of securing communications, we move on to key management for SCADA systems. Appropriate key management techniques are a crucial part of secure communications, and form an important part of the contributions made in this work. We present a key management protocol that has been designed to run under the constraints specific to SCADA systems. A reductionist security proof is developed for a simplified version of the protocol, showing it is secure in the Bellare Rogaway model.

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8

Dawson, Robert Edward. "Secure communications for critical infrastructure control systems." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20710/.

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In March 2000, 1 million litres of raw sewage was released into the water system of Maroochy Shire on Queensland’s sunshine coast. This environmental disaster was caused by a disgruntled ex-contractor using a radio transmitter to illicitly access the electronically controlled pumps in the control system. In 2007 CNN screened video footage of an experimental attack against a electrical generator. The attack caused the generator to shake and smoke, visually showing the damage caused by cyber attack. These attacks highlight the importance of securing the control systems which our critical infrastructures depend on. This thesis addresses securing control systems, focusing on securing the communications for supervisory control and data acquisition (SCADA) systems. We review the architectures of SCADA systems and produce a list of the system constraints that relate to securing these systems. With these constraints in mind, we survey both the existing work in information and SCADA security, observing the need to investigate further the problem of secure communications for SCADA systems. We then present risk modelling techniques, and model the risk in a simple SCADA system, using the ISM, a software tool for modelling information security risk. In modelling the risk, we verify the hypothesis that securing the communications channel is an essential part of an effective security strategy for SCADA systems. After looking at risk modelling, and establishing the value of securing communications, we move on to key management for SCADA systems. Appropriate key management techniques are a crucial part of secure communications, and form an important part of the contributions made in this work. We present a key management protocol that has been designed to run under the constraints specific to SCADA systems. A reductionist security proof is developed for a simplified version of the protocol, showing it is secure in the Bellare Rogaway model.

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9

Schwager, Mac. "Towards verifiable adaptive control for safety critical applications." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32344.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 97-101).
To be implementable in safety critical applications, adaptive controllers must be shown to behave strictly according to predetermined specifications. This thesis presents two tools for verifying specifications relevant to practical direct-adaptive control systems. The first tool is derived from an asymptotic analysis of the error dynamics of a direct adaptive controller and uncertain linear plant. The analysis yields a so called Reduced Linear Asymptotic System, which can be used for designing adaptive systems to meet transient specifications. The tool is demonstrated in two design examples from flight mechanics, and verified in numerical simulation. The second tool developed is an algorithm for direct-adaptive control of plants with magnitude saturation constraints on multiple inputs. The algorithm is a non-trivial extension of an existing technique for single input systems with saturation. Boundeness of all signals is proved for initial conditions in a compact region. In addition, the notion of a class of multi-dimensional saturation functions is introduced. The saturation compensation technique is demonstrated in numerical simulation. Finally, these tools are applied to design a direct-adaptive controller for a realistic multi-input aircraft model to accomplish control reconfiguration in the case of unforeseen failure, damage, or disturbances. A novel control design for incorporating control allocation and reconfiguration is introduced. The adaptive system is shown in numerical simulation to have favorable transient qualities and to give a stable response with input saturation constraints.
by Mac Schwager.
S.M.

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10

Lundahl, Kristoffer. "Modeling and Optimization for Critical Vehicle Maneuvers." Licentiate thesis, Linköpings universitet, Fordonssystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94010.

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As development in sensor technology, situation awareness systems, and computational hardware for vehicle systems progress, an opportunity for more advanced and sophisticated vehicle safety-systems arises. With the increased level of available information---such as position on the road, road curvature and knowledge about surrounding obstacles---future systems could be seen utilizing more advanced controls, exploiting at-the-limit behavior of the vehicle. Having this in mind, optimization methods have emerged as a powerful tool for offline vehicle-performance evaluation, providing inspiration to new control strategies, and by direct implementation in on-board systems. This will, however, require a careful choice of modeling and objectives, since the solution to the optimization problem will rely on this. With emphasis on vehicle modeling for optimization-based maneuvering applications, a vehicle-dynamics testbed has been developed. Using this vehicle in a series of experiments, most extensively in a double lane-change maneuver, verified the functionality and capability of the equipment. Further, a comparative study was performed, considering vehicle models based on the single-track model, extended with, e.g., tire-force saturation, tire-force lag and roll dynamics. The ability to predict vehicle behavior was evaluated against measurement data from the vehicle testbed. A platform for solving vehicle-maneuvering optimization-problems has been developed, with state-of-the-art optimization tools, such as JModelica.org and Ipopt. This platform is utilized for studies concerning the influence different vehicle-model configurations have on the solution to critical maneuvering problems. In particular, different tire modeling approaches, as well as vehicle-chassis models of various complexity, are investigated. Also, the influence different road-surface conditions-e.g., asphalt, snow and ice-have on the solution to time-optimal maneuvers is studied. The results show that even for less complex models-such as a single-track model with a Magic Formula based tire-model-accurate predictions can be obtained when compared to measurement data. The general observation regarding vehicle modeling for the time-critical maneuvers is similar; even the least complex models can be seen to capture certain characteristics analogous to those of higher complexity. Analyzing the results from the optimization problems, it is seen that the overall dynamics, such as resultant forces and yaw moment, obtained for different model configurations, correlates very well. For different road surfaces, the solutions will of course differ due to the various levels of tire-forces being possible to realize. However, remarkably similar vehicle paths are obtained, regardless of surface. These are valuable observations, since they imply that models of less complexity could be utilized in future on-board optimization-algorithms, to generate, e.g., yaw moment and vehicle paths. In combination with additional information from enhanced situation-awareness systems, this enables more advanced safety-systems to be considered for future vehicles.

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11

Mathew, Bijoy. "Implementing a hazard analysis critical control points plan (HACCP)." Menomonie, WI : University of Wisconsin--Stout, 2007. http://www.uwstout.edu/lib/thesis/2007/2007mathewb.pdf.

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12

Cao, Fang. "Control of doctors in the NHS : a critical appraisal." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539473.

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13

Doran, Carmen. "Modelling and control of hyperglycemia in critical care patients." Thesis, University of Canterbury. Mechanical Engineering, 2004. http://hdl.handle.net/10092/6478.

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Critically ill patients are known to experience stress-induced hyperglycemia. Inhibiting the physiological response to increased glycemic levels in these patients are factors such as increased insulin resistance, increased dextrose input, absolute or relative insulin deficiency, and drug therapy. Although hyperglycemia can be a marker for severity of illness, it can also worsen outcomes, leading to an increased risk of further complications. Hyperglycemia has been quantified in critically ill patients showing the need for glucose control. The development of a relatively simple system model and the verification of both generic and patient specific parameters have been successful in control trials and simulations over a range of critically ill patients. Stepwise reduction of blood glucose values by adaptive control was shown to be accurate to within 20%, and average long-term fitting errors are within the measurement error of the glucose sensor. A control algorithm capable of tight regulation for a glucose intolerant ICU patient would thus reduce mortality, as well as the burden on medical resources and time with current experience-based control approaches used in most critical care units. Overall, the research presented is a significant step towards fully automated adaptive control of hyperglycaemia in critically ill patients.

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14

Haylock, James Alexander. "Fault tolerant drives for safety critical applications." Thesis, University of Newcastle Upon Tyne, 1998. http://hdl.handle.net/10443/352.

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The correct operation of adjustable speed drives, which form part of a larger system, is often essential to the operation of the system as a whole. In certain applications the failure of such a drive could result in a threat to human safety and these applications are termed 'safety critical'. The chance of a component failure resulting in non-operation of the drive can be dramatically reduced by adopting a fault tolerant design. A fault tolerant drive must continue to operate throughout the occurrence of any single point failure without undue disturbance to the power output. Thereafter the drive must be capable of producing rated output indefinitely in the presence of the fault. The work presented in this thesis shows that fault tolerance can be achieved without severe penalties in terms of cost or power to mass ratio. The design of a novel permanent magnet drive is presented and a 'proof of concept' demonstrator has been built, based on a 20 kW, 13000 RPM aircraft fuel pump specffication. A novel current controller with near optimal transient performance is developed to enable precise shaping of the phase currents at high shaft speeds. The best operating regime for the machine is investigated to optimise the power to mass ratio of the drive. A list of the most likely electrical faults is considered. Some faults result in large fault currents and require rapid detection to prevent fault propagation. Several novel fault sensors are discussed. Fault detection and identification schemes are developed, including new schemes for rapid detection of turn to turn faults and power device short circuit faults. Post fault control schemes are described which enable the drive to continue to operate indefinitely in the presence of each fault. Finally, results show the initially healthy drive operating up to, through and beyond the introduction of each of the most serious faults.

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15

Wu, Guofan. "Safety-critical Geometric Control Design with Application to Aerial Transportation." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1108.

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Safety constraints are ubiquitous in many robotic applications. For instance, aerial robots such as quadrotors or hexcoptors need to realize fast collision-free flight, and bipedal robots have to choose their discrete footholds properly to gain the desired friction and pressure contact forces. In this thesis, we address the safety critical control problem for fully-actuated and under-actuated mechanical systems. Since many mechanical systems evolve on nonlinear manifolds, we extend the concept of Control Barrier Function to a new concept called geometric Control Barrier Function which is specifically designed to handle safety constraints on manifolds. This type of Control Barrier Function stems from geometric control techniques and has a coordinate free and compact representation. In a similar fashion, we also extend the concept of Control Lyapunov Function to the concept of geometric Control Lyapunov Function to realize tracking on the manifolds. Based on these new geometric versions of CLF and CBF, we propose a general control design method for fully-actuated systems with both state and input constraints. In this CBF-CLF-QP control design, the control input is computed based on a state-dependent Quadratic Programming (QP) where the safety constraints are strictly enforced using geometric CBF but the tracking constraint is imposed through a type of relaxation. Through this type of relaxation, the controller could still keep the system state safe even in the cases when the reference is unsafe during some time period. For a single quadrotor, we propose the concept of augmented Control Barrier Function specifically to let it avoid external obstacles. Using this augmented CBF, we could still utilize the idea of CBF-CLF-QP controller in a sequential QP control design framework to let this quadrotor remain safe during the flight. In meantime, we also apply the geometric control techniques to the aerial transportation problem where a payload is carried by multiple quadrotors through cable suspension. This type of transportation method allows multiple quadrotors to share the payload weight, but introduces internal safety constraints at the same time. By employing both linear and nonlinear techniques, we are able to carry the payload pose to follow a pre-defined reference trajectory.

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Nicholson, Mark. "Selecting a topology for safety-critical real-time control systems." Thesis, University of York, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263664.

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Karlsson, Christoffer. "Control of critical data flows : Automated monitoring of insurance data." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187733.

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EU insurance companies work on implementing the Solvency II directive, which calls for stronger focus on data quality and information controls. Information controls are procedures that can validate data at rest and data in motion to detect errors and anomalies. In this master thesis a case study was carried out at AMF, a Swedish pension insurance company, to identify and investigate their critical data flows and the controls performed in the respective flows. A purpose of this project is to help AMF ensure data quality requirements from the Financial Supervisory Authority that they have to fulfill. The thesis was conducted at AMF between September and December 2015, and included tasks such as carrying out interviews, Enterprise Architecture modeling, analysis, prototyping, product evaluation and calculation of a business case. A gap analysis was carried out to analyze the needs for change regarding existing information controls at AMF, where different states of the company are documented and analyzed. The current state corresponds to the present situation at the company including attributes to be improved while the future state outlines the target condition that the company wants to achieve. A gap between the current state and future state is identified and elements that make up the gap are presented in the gap description. Lastly, possible remedies for bridging the gap between the current and future state are presented. Furthermore, a prototype of an automated control tool from a company called Infogix has been implemented and analyzed regarding usability, governance and cost. A benefits evaluation was carried out on the information control tool to see whether an investment would be beneficial for AMF. The benefit evaluation was carried out using the PENG method, a Swedish model developed by three senior consultants that has been specially adjusted for evaluation of IT investments. The evaluation showed that such an investment would become beneficial during the second year after investment.
Försäkringsbolag i EU arbetar med införandet av Solvens II-direktivet som kräver att företag har ett större fokus på datakvalitet och informationskontroller. I detta examensarbete har en fältstudie utförts på AMF som är ett svenskt pensionsbolag. Arbetet har gått ut på att identifiera och undersöka kritiska dataflöden i företaget samt kontroller som utförs i dessa flöden. Ett syfte med arbetet var att hjälpa AMF att kunna påvisa att man uppfyller krav från finansinspektionen på datakvalitet och spårbarhet. Projektet utfördes under perioden september till december hösten 2015, vilket inkluderade arbetsuppgifter såsom intervjuer, Enterprise Architecture-modellering, implementering av prototyp, produktutvärdering samt kalkylering av ett business case. En gap-analys har utförts för att analysera behovet av förändringar på de nuvarande informationskontrollerna som finns på AMF, där olika lägen har dokumenterats och analyserats. Nuläget motsvarar hur situationen ser ut på företaget i dagsläget och fokuserar på de attribut som man vill förbättra, medan önskat läge beskriver de mål som företaget vill uppnå. Ett gap mellan nuläge och önskat läge identifieras tillsammans med de faktorer som utgör skillnaden mellan dessa lägen presenteras. Till sist presenteras tänkbara åtgärder för att uppnå önskat läge. Som en del av detta examensarbete har en prototyp av ett automatiserat kontrollverktyg från ett företag som heter Infogix implementerats och utvärderas med avseende på användbarhet, styrning och kostnad. En nyttovärdering har utförts på kontrollverktyget för att undersöka huruvida en investering skulle vara gynnsam för AMF. Nyttovärderingen gjordes med hjälp av PENG, en svensk nyttovärderingsmodell utvecklad av tre ekonomer/IT-konsulter, som har anpassat speciellt för att bedöma IT-investeringar. Värderingen visade på att en sådan investering skulle komma att bli gynnsam under andra året efter att investeringen gjordes.

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18

Shuja, Sana. "Formal Verification Techniques for Safety Critical Medical Device Software Control." Diss., North Dakota State University, 2016. http://hdl.handle.net/10365/25736.

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Safety-critical medical devices play an important role in improving patients health and lifestyle. Faulty behaviors of such devices can cause harm or even death. Often these faulty behaviors are caused due to bugs in software programs used for digital control of the device. We present a formal veri cation methodology that can be used to check the correctness of object code programs that implement the safety-critical control functions of these medical devices. Our methodology is based on the theory of Well-Founded Equivalence Bisimulation (WEB) re nement, where both formal speci cations and implementations are treated as transition systems. First, we present formal speci cation model for the medical device. Second, we develop correctness proof obligations that can be applied to validate object code programs used in these devices. Formal methods are not widely employed for the veri cation of safety critical medical devices. However, using our methodology we were able to bridge the gap between two very important phases of software life cycle: speci cation and veri cation.

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19

Chakravarthy, Rasika Mudumbai. "Long-lived authentication protocols for critical infrastructure process control systems." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Spring2009/r_mudumbai_chakravarthy_041509.pdf.

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Thesis (M.S. in computer science )--Washington State University, May 2009.
Title from PDF title page (viewed on March 29, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 112-115).

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20

Blakemore, Amy. "Insulin sensitivity tools for critical care." Thesis, University of Canterbury. Mechanical Engineering, 2009. http://hdl.handle.net/10092/2606.

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Stress induced hyperglycaemia is prevalent in critical care. Since the landmark paper published by Van den Berghe et al. (2001) a great deal of attention has been paid to intensive insulin therapy in an ICU setting to combat the adverse effects of elevated glucose levels and poor glycaemic control. Glycaemic control protocols have been extensively developed, tested and validated within an ICU setting. However, little research has been conducted on the effects of a glycaemic control protocol in a less acute ward setting. There are many additional challenges presented in a ward setting, such as the variation in meals and levels of activity between patients, from day to day and throughout the day. A simple compartment model is used to describe the nature of insulin and glucose metabolism in patients of the Cardiothoracic Ward (CTW). A stochastic model of the fitted insulin sensitivity parameter is generated for this cohort and validated against cohorts of similar characteristics. The stochastic model is then used to run simulations of predictive control on 7 CTW patients, which shows significantly tighter glucose control than what is obtained with regular clinical procedures. However, the rate of severe hypoglycaemia is an unacceptably high 4.2%. The greatest challenge in maintaining tight glycaemic control in such patients is the consumption of meals at irregular times and of inconsistent quantities. Insulin sensitivity was compared to extensive hourly clinical data of 36 ICU patients. From this data a sepsis score of value 0-4 was generated as gold standard marker of sepsis. Comparing the sepsis score to insulin sensitivity found that insulin sensitivity provides a negative predictive diagnostic for sepsis. High insulin sensitivity of greater than Si = 8 x 10⁻⁵ L mU⁻¹ min⁻¹ rules out sepsis for the majority of patient hours and may be determined non-invasively in real-time from glycaemic control protocol data. Low insulin sensitivity is not an effective diagnostic, as it can equally mark the presence of sepsis or other conditions.

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21

Sebusang, Sebusang E. M. "Minimal control synthesis algorithm : safety-critical and a priori design issues." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389031.

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22

Oh, Sang-soo. "STUDY ON MICROSTRUCTURE CONTROL AND CRITICAL CURRENT DENSITY OF SUPERCONDUCTING MATERIALS." Kyoto University, 1992. http://hdl.handle.net/2433/168753.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第5100号
工博第1221号
新制||工||866(附属図書館)
UT51-92-J147
京都大学大学院工学研究科冶金学専攻
(主査)教授長村光造, 教授志賀正幸, 教授山口正治
学位規則第4条第1項該当

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23

Wagude, Bethsheba Emily Akinyi. "Hazard analysis critical control point (HACCP) in a red meat abattoir." Diss., University of Pretoria, 1999. http://hdl.handle.net/2263/28615.

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24

Coxford, Sheilah. "A critical analysis of firearm control in post-apartheid South Africa." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/3793.

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Summary in English.
Bibliography: leaves 87-92.
This dissertation evaluates the hypothesis that the implementation of stringent firearm control in South Africa will significantly decrease levels of violent crime. First, the specific dynamics of violent crime in this country are examined, in order to establish whether firearm control constitutes a fitting response to the problem. Second, some of the important theoretical underpinnings of the firearms control debate are considered.

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Abdelaty, Maged Fathy Youssef. "Robust Anomaly Detection in Critical Infrastructure." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/352463.

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Critical Infrastructures (CIs) such as water treatment plants, power grids and telecommunication networks are critical to the daily activities and well-being of our society. Disruption of such CIs would have catastrophic consequences for public safety and the national economy. Hence, these infrastructures have become major targets in the upsurge of cyberattacks. Defending against such attacks often depends on an arsenal of cyber-defence tools, including Machine Learning (ML)-based Anomaly Detection Systems (ADSs). These detection systems use ML models to learn the profile of the normal behaviour of a CI and classify deviations that go well beyond the normality profile as anomalies. However, ML methods are vulnerable to both adversarial and non-adversarial input perturbations. Adversarial perturbations are imperceptible noises added to the input data by an attacker to evade the classification mechanism. Non-adversarial perturbations can be a normal behaviour evolution as a result of changes in usage patterns or other characteristics and noisy data from normally degrading devices, generating a high rate of false positives. We first study the problem of ML-based ADSs being vulnerable to non-adversarial perturbations, which causes a high rate of false alarms. To address this problem, we propose an ADS called DAICS, based on a wide and deep learning model that is both adaptive to evolving normality and robust to noisy data normally emerging from the system. DAICS adapts the pre-trained model to new normality with a small number of data samples and a few gradient updates based on feedback from the operator on false alarms. The DAICS was evaluated on two datasets collected from real-world Industrial Control System (ICS) testbeds. The results show that the adaptation process is fast and that DAICS has an improved robustness compared to state-of-the-art approaches. We further investigated the problem of false-positive alarms in the ADSs. To address this problem, an extension of DAICS, called the SiFA framework, is proposed. The SiFA collects a buffer of historical false alarms and suppresses every new alarm that is similar to these false alarms. The proposed framework is evaluated using a dataset collected from a real-world ICS testbed. The evaluation results show that the SiFA can decrease the false alarm rate of DAICS by more than 80%. We also investigate the problem of ML-based network ADSs that are vulnerable to adversarial perturbations. In the case of network ADSs, attackers may use their knowledge of anomaly detection logic to generate malicious traffic that remains undetected. One way to solve this issue is to adopt adversarial training in which the training set is augmented with adversarially perturbed samples. This thesis presents an adversarial training approach called GADoT that leverages a Generative Adversarial Network (GAN) to generate adversarial samples for training. GADoT is validated in the scenario of an ADS detecting Distributed Denial of Service (DDoS) attacks, which have been witnessing an increase in volume and complexity. For a practical evaluation, the DDoS network traffic was perturbed to generate two datasets while fully preserving the semantics of the attack. The results show that adversaries can exploit their domain expertise to craft adversarial attacks without requiring knowledge of the underlying detection model. We then demonstrate that adversarial training using GADoT renders ML models more robust to adversarial perturbations. However, the evaluation of adversarial robustness is often susceptible to errors, leading to robustness overestimation. We investigate the problem of robustness overestimation in network ADSs and propose an adversarial attack called UPAS to evaluate the robustness of such ADSs. The UPAS attack perturbs the inter-arrival time between packets by injecting a random time delay before packets from the attacker. The attack is validated by perturbing malicious network traffic in a multi-attack dataset and used to evaluate the robustness of two robust ADSs, which are based on a denoising autoencoder and an adversarially trained ML model. The results demonstrate that the robustness of both ADSs is overestimated and that a standardised evaluation of robustness is needed.

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Yachouh, Marwan. "Re-authentication of Critical Operations." Thesis, Linköping University, Department of Electrical Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1174.

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This is a study on the development of a re-authentication prototype. Re- authentication serves as a receipt for e.g. system administrators that authorise them to carry out a critical operation in a system that already is protected by a security architecture. A critical operation is a kind of operation that can cause serious damage to a network node or a set of network nodes, if it is done without one giving it a second thought. The purpose is to prevent mistakes and secure the users’ audit trail.

The main task is to propose and implement a re-authentication prototype, that is to enable the incorporation of the re-authentication prototype to an already complete security architecture and yet preserve the security and performance level of the architecture.

This thesis deals with this problem by using digitally signed certificates to provide the necessary security issues. The certificates used are called re- authentication certificates and follows the X.509 attribute certificate standard. The re-authentication certificate is optimised so that it only holds authorisation information regarding one critical operation. An access control decision function is used to decide if the re-authentication certificate and its owner are authentic. On basis of that decision the user can get the authority to execute critical operations.

The finished prototype confirms that a re-authentication can be incorporated with the security architecture. The report also shows that the security status of the architecture is preserved. The performance of the prototype is rather difficult to prove since the prototype implementation only initialises the objects that are required to prove the security issues. A performance test can therefore never prove how the prototype will perform in an authentic environment. The performance is assumed to be adequate since it uses the same authentication function that is used by the security architecture.

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Cooper, Trudi. "Quality management in Australian higher education : A critical review." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2004. https://ro.ecu.edu.au/theses/842.

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Quality management in higher education is a politically contentious issue in Australia. as it is in North America, New Zealand, and many European countries. The Australian government has instituted a quality management system for higher education that it claims will improve university efficiency, accountability and quality. Critics assert that the current quality management system is detrimental to universities and undermines the capability of universities to deliver maximal benefits to individuals and to society. Evaluation of the basis of conflicting claims is necessary to enable decisions about the usefulness of current practices and decisions about whether existing quality management arrangements should be retained, modified and developed, or replaced, or, abolished.

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Broomfield, Eamon J. "The integration of hazard evaluation procedures and requirements engineering for safety-critical embedded systems." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/32816.

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Although much work has been done on assessing safety requirements in programmable systems, one very important aspect, the integration of hazard evaluation procedures and requirements engineering, has been somewhat neglected. This thesis describes the derivation and application of a methodology, HAZAPS (HAZard Assessment in Programmable Systems). The methodology assists at the requirements stage in the development of safety-critical embedded systems. The objectives are to identify hazards in programmable systems, construct and model the associated safety requirements, and, finally, to assess these requirements. HAZAPS integrates safety engineering and software modelling techniques. The analysis of more than 300 computer related incidents provided the criteria used to identify, select and modify safety engineering techniques.

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Gaadingwe, Tshepo Gaadingwe. "A critical review of the IFIP TC11 Security Conference Series." Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/507.

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Over the past few decades the field of computing has grown and evolved. In this time, information security research has experienced the same type of growth. The increase in importance and interest in information security research is reflected by the sheer number of research efforts being produced by different type of organizations around the world. One such organization is the International Federation for Information Processing (IFIP), more specifically the IFIP Technical Committee 11 (IFIP TC11). The IFIP TC11 community has had a rich history in producing high quality information security specific articles for over 20 years now. Therefore, IFIP TC11 found it necessary to reflect on this history, mainly to try and discover where it came from and where it may be going. Its 20th anniversary of its main conference presented an opportunity to begin such a study of its history. The core belief driving the study being that the future can only be realized and appreciated if the past is well understood. The main area of interest was to find out topics which may have had prevalence in the past or could be considered as "hot" topics. To achieve this, the author developed a systematic process for the study. The underpinning element being the creation of a classification scheme which was used to aid the analysis of the IFIP TC11 20 year's worth of articles. Major themes were identified and trends in the series highlighted. Further discussion and reflection on these trends were given. It was found that, not surprisingly, the series covered a wide variety of topics in the 20 years. However, it was discovered that there has been a notable move towards technically focused papers. Furthermore, topics such as business continuity had just about disappeared in the series while topics which are related to networking and cryptography continue to gain more prevalence.

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Gharat, Asmita. "Bluetooth based dynamic critical route volume estimation on signalized arterials." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76871.

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Bluetooth Data collection technique is recently proven as a reliable data collection technique that provides the opportunity to modify traditional methodologies to improve system performance. Actual volume in the network is a result of the timing plans which are designed and modified based on the volume which is generated using existing timing plans in the system. This interdependency between timing plan and volume on the network is a dynamic process and should be captured to obtain actual traffic states in the network. The current practice is to calculate synthetic origin destination information based on detector volume that doesn't necessarily represent the volume scenario accurately. The data from Bluetooth technology can be utilized to calculate dynamic volume on the network which can be further used as input for signal timing design. Application of dynamic volume improves the system performance by providing the actual volume in system to design optimal timing plans. This thesis proposes a framework that can be used to integrate data obtained from the Bluetooth technology with the traditional methods to design timing plans. The proposed methodology utilizes the origin destination information obtained from Bluetooth data, detector data, characteristics of intersections such as number of lanes, saturation flow rate and existing timing plans as a basis for the calculation of the dynamic volume for the various movements at each intersection. The study shows that using the Bluetooth based OD matrix to calculate accurate dynamic volumes results in better system performance compared to the traditional way of using the static detector volume alone.
Master of Science

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31

Green, Melinda E. Voigt Robert C. "Critical assessment of current metalcasting green sand system control and monitoring processes." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4793/index.html.

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Lemmer, Hermann Richard. "The tuberculosis control programme in the industry in Swaziland : a critical evaluation." Diss., Access to E-Thesis, 2002. http://upetd.up.ac.za/thesis/available/etd-10032005-092729/.

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Ashraf, Muhammad Junaid. "Management control changes in a public sector firm : A critical realist analysis." Thesis, University of Essex, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531563.

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Otto, Gustav. "Critical comparison of control techniques for a flight dynamics controller / Gustav Otto." Thesis, North-West University, 2011. http://hdl.handle.net/10394/8068.

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This dissertation covers the process of modelling and subsequently developing a flight dynamics controller for a quad–rotor unmanned aerial vehicle. It is a theoretical study that focusses on the selection of a controller type by first analysing the problem on a system level and then on a technical level. The craft is modelled using the Newton– Euler model, accounting for multiple reference frames to account for the interpretation of orientation as seen by on–board sensors. The quad–rotor model and selected controllers are characterized and compared. The model is verified through simulation by comparison to a validated model. A series of generic control loops are derived and used as reference for the implementation of the controllers. A Simulator is developed and used to do a comparative study of the various controller types and the control approach. Finally a full simulation is done to demonstrate the interaction between the controllers.
Thesis (MIng (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2012.

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Blow, James Raymond. "Use of formal methods in the development of safety critical control software." Thesis, University of York, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288811.

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Firstly, we extend the Generalised Substitution Language, and therefore the principles of weakest precondition calculus, to embrace differential constraints. Our approach is based on generalising the traditional view that a Generalised Substitution specifies a fragment of a sequential programme. We consider a Generalised Substitution to represent an autonomous transformation which is 'clocked' repeatedly to perform its computation at regular intervals. In the case of such components composed synchronously, we can generalise the notion of weakest precondition to traces (sequences of values) of inputs and outputs. In our approach we characterise traces with first order constraints as 'step' predicates over adjacent elements in the trace. We refer to these as 'acceptance criteria'. We also generalise our calculus to cover nth order differentials. Secondly, we adapt weakest precondition to traces characterised by state machines which represent sequencing constraints. We do this by introducing a form of state machines called 'acceptance machines' which constrain traces of variable values in an alternative way to differential properties. Using the Generalised Substitution Language once more we present a semantics for the propagation of acceptance machines in a manner analagous to predicate transformers. We also use acceptance machines to specify safety properties which have been derived from the safety process. The requirements can then be shown correct with respect to these properties. Finally, we consolidate and integrate our differential calculus and state machine theory with a domain specific formal framework, focusing on the practical application of the theory in a real engineering setting. The domain specific framework which we have selected is Practical Formal Specification. It is a framework which has been developed specifically for use in the engine (and aircraft) control software domain and is based on the decomposition of requirements into components whose usage can be scoped by the specification of environmental and contextual assumptions.

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Diao, El Hadji Sidath. "Fault Tolerant Control for Critical machine-inverter systems used in automotive industry." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112311/document.

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La disponibilité de certains capteurs est indispensable pour le contrôle des machines électriques dans une application automobile. Cette thèse constitue une contribution à l'étude d'une commande tolérante aux défauts pour un entraînement électrique dans le cadre du projet SOFRACI. Pour pallier une défaillance de ces capteurs, des stratégies sont mises en place pour assurer une continuité de fonctionnement ou un arrêt sûr. Dans le cas de la machine synchrone, les capteurs les plus critiques sont: le capteur de position, les capteurs de courant et le capteur de bus de tension continue. C'est dans ce contexte que l'on a développé des algorithmes de commande tolérante aux défauts avec successivement des étapes de détection, d'isolation et de reconfiguration. Ensuite, la validation expérimentale a été effectuée sur un banc composé d’une machine synchrone et d’un onduleur avec 3 ponts H conçus pour la propulsion d’un véhicule électrique. Ainsi les méthodes développées et qui s’appuient principalement sur la théorie du contrôle, sont évaluées expérimentalement à travers des injections de défauts en temps réel, avec un accent mis sur le temps nécessaire à la détection
During the last decade, Fault Tolerant Control (FTC) has become an increasingly interesting topic in automotive industry. The operation of electrical drives is highly dependent on feedback sensors availability. With the aim of reaching the required level of availability in transportation applications, the drive is equipped with a DC voltage sensor, three current sensors (due to safety requirements in electric vehicle standards) and a position sensor. This PhD is a contribution to the study of an electrical drive fault tolerant control. The objective is to have a system, which can adaptively reorganizes itself at a sensor failure occurrence. Consequently, strategies are defined from the early preliminary design steps, so as to facilitate fault detection, fault isolation and control reconfiguration. To this purpose, our work goes from theoretical studies toward experimental validations through the model simulation using control theory.In this thesis, FTC algorithms are developed for the rotor position, the phase currents and DC link voltage sensors. The experimentally validation is perform with an electrical drive composed of a Permanent Magnet Synchronous Machine and a 3H bridge inverter. Thus, the developed methods are evaluated experimentally through real time fault injection, with an emphasis on the detection time

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Smedley, Peter John. "Development of computer based aids to hazard analysis critical control point (HACCP)." Thesis, London South Bank University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245126.

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The Razard Analysis Critical Control Point (RACCP) system has been in existence as a method of quality assurance for over 30 years. During this time it has evolved considerably, along with the food industry in which it is applied. Rowever, only in the last few years has the system achieved widespread acceptance as one of the most effective methods of controlling foodborne hazards and its principles come to be included in national legislation. Whilst the greater implementation of RACCP has the recognised potential to bring great gains in terms of food safety assurance, the technical nature of its procedure, which seeks to identify hazards and prevent their occurrence via specifically targeted control measures (Critical Control Points (CCPs», has caused some considerable difficulties in its operation. Identifying that there was a real need for the dissemination and subsequent application of expertise in RACCP, this piece of research work has aimed to develop a method of aiding the practical implementation of RACCP. A computer based solution was chosen for its potential to store, organise and access large amounts of information and data which could be used interactively by the user to conduct a RACCP study. Through the experiences of several companies with RACCP implementations and the completion of a traditional RACCP study with a collaborating company, requirements for expertise on RACCP have been identified in two main areas. The first requirement was for knowledge, in particular with regard to hazard identification. The second requirement was for a more clearly defined structure for the RACCP study itself, in particular with regard to hazard analysis. Aiming to address these aspects, two computer applications based around relational databases have been developed. This development together with limited field testing of the second application have provided an insight into many of the problems associated with the practice of RACCP as well as demonstrated the potential of computer based systems to both disseminate information and aid decision processes in this area.

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Reedman, Adam Victor Creyke. "The design and control of a manipulator for safety-critical deployment applications." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/33736.

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Development of manipulators that interact closely with humans has been a focus of research in fields such as robot-assisted surgery The recent introduction of powered surgical-assistant devices into the operating theatre has meant that modified industrial robot manipulators have been required to interact with both patient and surgeon Some of these robots require the surgeon to grasp the end-effector and apply a force while the joint actuators provide resistance to motion In the operating theatre, the use of high-powered mechanisms to perform these tasks could compromise the safety of the patient, surgeon and operating room staff. In this investigation, a two degrees-of-freedom (2-DoF) manipulator is designed for the purpose of following a pre-defined path under the direct control of the surgeon.

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Просвірін, Дмитро Андрійович. "DEVELOPING AND DEPLOYING HMIS ON CRITICAL EMBEDDED GRAPHICS PLATFORMS FOR AFCS CONTROL." Thesis, Національний авіаційний університет, 2015. http://er.nau.edu.ua/handle/NAU/17207.

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Critical embedded Human Machine Interfaces (HMI) play an important role within the aerospace and defense. Developing HMIs efficiently while adhering to specific safety standards like DO-178B/C is a challenging task.

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Усенко, А. А. "Порядок впровадження системи hazard analysis and critical control points (HACCP) в Україні." Thesis, Молодіжний науковий юридичний форум: [Матеріали міжн. наук.-практ. конф. До дня науки, м. Киїів, НАУ, 18 травня 2018р.] Том 1.- Тернопіль: Вектор, 2018. С. 149-151, 2018. http://er.nau.edu.ua/handle/NAU/34742.

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Rezvani, Arany Roushan. "Gaussian Process Model Predictive Control for Autonomous Driving in Safety-Critical Scenarios." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-161430.

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This thesis is concerned with model predictive control (MPC) within the field of autonomous driving. MPC requires a model of the system to be controlled. Since a vehicle is expected to handle a wide range of driving conditions, it is crucial that the model of the vehicle dynamics is able to account for this. Differences in road grip caused by snowy, icy or muddy roads change the driving dynamics and relying on a single model, based on ideal conditions, could possibly lead to dangerous behaviour. This work investigates the use of Gaussian processes for learning a model that can account for varying road friction coefficients. This model is incorporated as an extension to a nominal vehicle model. A double lane change scenario is considered and the aim is to learn a GP model of the disturbance based on previous driving experiences with a road friction coefficient of 0.4 and 0.6 performed with a regular MPC controller. The data is then used to train a GP model. The GPMPC controller is then compared with the regular MPC controller in the case of trajectory tracking. The results show that the obtained GP models in most cases correctly predict the model error in one prediction step. For multi-step predictions, the results vary more with some cases showing an improved prediction with a GP model compared to the nominal model. In all cases, the GPMPC controller gives a better trajectory tracking than the MPC controller while using less control input.

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Rahman, Anisur. "Rare sequential pattern mining of critical infrastructure control logs for anomaly detection." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/132077/1/__qut.edu.au_Documents_StaffHome_staffgroupW%24_wu75_Documents_ePrints_Anisur_Rahman_Thesis_Redacted.pdf.

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Supervisory Control and Data Acquisition (SCADA) systems are used to drive much of a nation's critical infrastructure, which by definition is essential for the nation's citizens' way of life. They are connected to the computer networks and internet systems to operate, control and monitor their operations. This connectivity enables these SCADA systems to be exposed to cyber-attacks. This thesis detects anomalies or cyber-attacks on SCADA systems. It analyses SCADA control logs to find abnormal process activities which are treated as anomalies. A novel rare sequential pattern mining approach is proposed and developed to find rare or abnormal behaviour in SCADA systems.

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Abdul, Razak Normy Norfiza. "Robust Modelling of the Glucose-Insulin System for Tight Glycaemic Control of Less Critical Care Patients." Thesis, University of Canterbury. Department of Mechanical Engineering, 2012. http://hdl.handle.net/10092/7039.

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In the intensive care units, hyperglycaemia among the critically ill is associated with poor outcomes. Many studies have been done on managing hyperglycaemia in the critically ill. Patients in the ICU continue to benefit from the outcome of extensive studies including several randomized clinical trials on glycaemic control with intensive insulin therapy. Tight glycaemic control has now emerged as a major research focus in critical care due to its potential to simultaneously reduce both mortality and cost. Although the debate on tight glycaemic control is on going, managing glycaemic level in ICUs is gaining widespread acceptance as the adverse effects are well known. However, in the less acute wards, to date there have only been a single randomized, controlled study to examine the benefit of glycaemic control. Patients in the less acute wards do not receive the same level of care, as glycaemic control is not regarded as important and not a priority. Glycaemic goals in the less acute wards are often judged based on clinical experience rather than adhering to a standard protocol or a treatment guideline. It is important that patients in the less acute wards received the level of care as practised in the ICU. If hyperglycaemia worsens outcome in the ICU, a similar effect is seen within less acute wards. Hence, tight glycaemic control needs to be extended in the less critical setting as well. To support the establishment of a control protocol for patients in less acute wards, a method that has been successful in the critical care and can be adapted to the less acute wards, is the model based or model-derived control protocol. Model-based protocol can deliver a safe and effective patient-specific control, which means the glycaemic control protocol can be devised to each individual patient. Hence, a physiological model that represents the glucose-insulin regulatory system is presented in this thesis. The developed model, Intensive Control Insulin-Nutrition-Glucose (ICING) is based on the best aspects of two previous clinically-validated glucose-insulin models.

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Underwood, B. Alan. "A framework for the certification of critical application systems." Thesis, Queensland University of Technology, 1994.

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Wang, Timothy. "Credible autocoding of control software." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53954.

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Formal methods is a discipline of using a collection of mathematical techniques and formalisms to model and analyze software systems. Motivated by the new formal methods-based certification recommendations for safety-critical embedded software and the significant increase in the cost of verification and validation (V\&V), this research is about creating a software development process for control systems that can provide mathematical guarantees of high-level functional properties on the code. The process, dubbed credible autocoding, leverages control theory in the automatic generation of control software documented with proofs of their stability and performance. The main output of this research is an automated, credible autocoding prototype that transforms the Simulink model of the controller into C code documented with a code-level proof of the stability of the controller. The code-level proof, expressed using a formal specification language, are embedded into the code as annotations. The annotations guarantee that the auto-generated code conforms to the input model to the extent that key properties are satisfied. They also provide sufficient information to enable an independent, automatic, formal verification of the auto-generated controller software.

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CAIROLI, FRANCESCA. "Deep Learning for Abstraction, Control and Monitoring of Complex Cyber-Physical Systems." Doctoral thesis, Università degli Studi di Trieste, 2022. http://hdl.handle.net/11368/3031103.

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Cyber-Physical Systems (CPS) consist of digital devices that interact with some physical components. Their popularity and complexity are growing exponentially, giving birth to new, previously unexplored, safety-critical application domains. As CPS permeate our daily lives, it becomes imperative to reason about their reliability. Formal methods provide rigorous techniques for verification, control and synthesis of safe and reliable CPS. However, these methods do not scale with the complexity of the system, thus their applicability to real-world problems is limited. A promising strategy is to leverage deep learning techniques to tackle the scalability issue of formal methods, transforming unfeasible problems into approximately solvable ones. The approximate models are trained over observations which are solutions of the formal problem. In this thesis, we focus on the following tasks, which are computationally challenging: the modeling and the simulation of a complex stochastic model, the design of a safe and robust control policy for a system acting in a highly uncertain environment and the runtime verification problem under full or partial observability. Our approaches, based on deep learning, are indeed applicable to real-world complex and safety-critical systems acting under strict real-time constraints and in presence of a significant amount of uncertainty.
Cyber-Physical Systems (CPS) consist of digital devices that interact with some physical components. Their popularity and complexity are growing exponentially, giving birth to new, previously unexplored, safety-critical application domains. As CPS permeate our daily lives, it becomes imperative to reason about their reliability. Formal methods provide rigorous techniques for verification, control and synthesis of safe and reliable CPS. However, these methods do not scale with the complexity of the system, thus their applicability to real-world problems is limited. A promising strategy is to leverage deep learning techniques to tackle the scalability issue of formal methods, transforming unfeasible problems into approximately solvable ones. The approximate models are trained over observations which are solutions of the formal problem. In this thesis, we focus on the following tasks, which are computationally challenging: the modeling and the simulation of a complex stochastic model, the design of a safe and robust control policy for a system acting in a highly uncertain environment and the runtime verification problem under full or partial observability. Our approaches, based on deep learning, are indeed applicable to real-world complex and safety-critical systems acting under strict real-time constraints and in presence of a significant amount of uncertainty.

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Santini, Norman Gabriele Antonio. "Quality Control procedure management for critical drawing parts of a two-seater helicopter." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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The goal of this thesis is to study the various mechanical parts of a two-seater helicopter, give an objective method to establish the criticism and the necessity of a Quality Control and/or a Dimensional Control by examining the technical drawings and using some common industrial software.

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Magnini, Matteo. "An information theory analysis of critical Boolean networks as control software for robots." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23062/.

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This work is an analysis of critical random Boolean networks used as control software for robots. The main goal is to find if there are relations between information theory measures on robot's sensors and actuators and the capability of the robot to achieve a particular task. Secondary goals are to verify if just the number of nodes of the networks is significant to obtain better populations of controllers for a given task and if a Boolean network can perform well in more than one single task. Results show that for certain tasks there is a strongly positively correlation between some information theory measures and the objective function of the task. Moreover Boolean networks with an higher number of nodes tend to perform better. These results can be useful in the automatic design process of control software for robots. Finally some Boolean networks from a random generated population exhibit phenotypic plasticity, which is the ability to manifest more phenotypes from the same genotype in different environments. In this scenario it is the capability of the same Boolean network (same functions and connections) to successfully achieve different tasks.

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Martin, Steven George. "The critical period of weed control in canola (Brassica napus L.) in Manitoba." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0024/MQ51762.pdf.

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Amici, Federica. "Inhibitory control and other cognitive abilities critical to fission-fusion dynamics in primates." Thesis, Liverpool John Moores University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497008.

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According to the ''Social Brain Hypothesis'', social complexity would be a main selective pressure for enhanced cognitive skills. Recently, high levels of fission-fusion dynamics have been proposed as one important aspect of social complexity, since individuals have to deal with more frequent changes in subgroup size and composition. Consequently, they might also show an enhancement of some cognitive skills critical to fission-fusion dynamics.

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Dissertations / Theses on the topic 'Critical control'

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