Tool-Based Design and Evaluation of Resilient Flight Control Systems

Communications engineering / telecommunication

Chapter Tool-Based Design and Evaluation of Resilient Flight Control Systems

Communications engineering / telecommunication

Data-based fault detection in chemical processes: Managing records with operator intervention and uncertain labels

Developing data-driven fault detection systems for chemical plants requires managing uncertain data labels and dynamic attributes due to operator-process interactions. Mislabeled data is a known problem in computer science that has received scarce attention from the process systems community. This work introduces and examines the effects of operator actions in records and labels, and the consequences in the development of detection models. Using a state space model, this work proposes an iterative relabeling scheme for retraining classifiers that continuously refines dynamic attributes and labels. Three case studies are presented: a reactor as a motivating example, flooding in a simulated de-Butanizer column, as a complex case, and foaming in an absorber as an industrial challenge. For the first case, detection accuracy is shown to increase by 14% while operating costs are reduced by 20%. Moreover, regarding the de-Butanizer column, the performance of the proposed strategy is shown to be 10% higher than the filtering strategy. Promising results are finally reported in regard of efficient strategies to deal with the presented problemPeer ReviewedPostprint (author's final draft

What is the impact of psychiatric decision units on mental health crisis care pathways? Protocol for an interrupted time series analysis with a synthetic control study

Background The UK mental health system is stretched to breaking point. Individuals presenting with mental health problems wait longer at the ED than those presenting with physical concerns and finding a bed when needed is difficult – 91% of psychiatric wards are operating at above the recommended occupancy rate. To address the pressure, a new type of facility – psychiatric decision units (also known as mental health decision units) – have been introduced in some areas. These are short-stay facilities, available upon referral, targeted to help individuals who may be able to avoid an inpatient admission or lengthy ED visit. To advance knowledge about the effectiveness of this service for this purpose, we will examine the effect of the service on the mental health crisis care pathway over a 4-year time period; the 2 years proceeding and following the introduction of the service. We use aggregate service level data of key indicators of the performance of this pathway. Methods Data from four mental health Trusts in England will be analysed using an interrupted time series (ITS) design with the primary outcomes of the rate of (i) ED psychiatric presentations and (ii) voluntary admissions to mental health wards. This will be supplemented with a synthetic control study with the same primary outcomes, in which a comparable control group is generated for each outcome using a donor pool of suitable National Health Service Trusts in England. The methods are well suited to an evaluation of an intervention at a service delivery level targeting population-level health outcome and the randomisation or ‘trialability’ of the intervention is limited. The synthetic control study controls for national trends over time, increasing our confidence in the results. The study has been designed and will be carried out with the involvement of service users and carers. Discussion This will be the first formal evaluation of psychiatric decision units in England. The analysis will provide estimates of the effect of the decision units on a number of important service use indicators, providing much-needed information for those designing service pathways

СИСТЕМНІ МЕТОДИ РЕКОНФІГУРАЦІЇ КЕРУВАННЯ ПОВІТРЯНИМ КОРАБЛЕМ В ОСОБЛИВИХ СИТУАЦІЯХ У ПОЛЬОТІ

The article explains the possibility of applying the systemic methods of parametric, structural control and purpose reconfiguration. The article explains the possibility of applying the systemic of parametric methods, structural reconfiguration management and reconfiguration of the object control objectives to prevent the transition to the current flight situation into a catastrophic one and maintain the specified level of safety. The article presents a block diagram of a control system developed reconfigurable dynamic system, and describes how it works.Аналіз статистичних даних ICAO показав, що майже 30 % авіаційних пригод виникають з причин втрати керованості повітряних кораблів (ПК) у польоті. Також за даними Федерального управління цивільної авіації США (FAA) щорічно в цивільній авіації трапляється до п’яти великих авіаційних пригод, вагома частка яких припадає на зіткнення літаків з біологічними, механічними або електричними формуваннями. У ПК попередніх поколінь з причин відсутності засобів автоматичної реконфігурації керування ці функції покладено на екіпаж. У цьому випадку результат реконфігурації керування повністю залежить від уміння, досвіду та особистих характеристик пілота, хоча принципово реконфігурація дозволила запобігти 70 % випадків тяжких авіаційних пригод через пошкодження зовнішніх обводів ПК, а також відмов приводів і кермових органів (висновок зроблено на підставі аналізу причин авіаційних пригод, що сталися в США). У роботі пропонується концепція системи автоматичного керування (САК) із функціями реконфігурації, що забезпечує відновлення керованості та стійкості ПК в умовах виникнення особливої ситуації (ОС) за рахунок реконфігурації керувальних сигналів, структури системи, конфігурації ПК або цільових завдань, тобто збереження безпечного режиму польоту. Під параметричною реконфігурацією розуміється зміна коефіцієнтів (передатних чисел) зворотних зв’язків для відновлення заданих характеристик динамічної стійкості і керованості ПК в умовах раптового виникнення незначних пошкоджень його зовнішніх обводів. Наприклад, після зіткнення ПК з біологічними, механічними або електричними формуваннями виникають пробої, вм’ятини та розриви зовнішньої обшивки, які призводять до часткової зміни їх аеродинамічних характеристик у польоті. Структурна реконфігурація полягає в перерозподілі керувальних дій на справні органи механізації для створення необхідних керувальних сил і моментів, що забезпечують відновлення керованості і стійкості ПК в умовах виникнення аварійної ситуації у польоті. Наприклад, у листопаді 2003 р. літак Airbus A300 обстріляли бойовики після зльоту у Багдаді. В результаті потрапляння ракети було істотно пошкоджено лівий закрилок, але екіпажу вдалося відновити стійкість і керованість ПК за рахунок зміни тяги двигунів та здійснити успішну аварійну посадку. Реконфігурація об'єкта – зміна конфігурації ПК, тобто надання органам механізації додаткових невластивих у штатному режимі польоту функцій для запобігання розвитку катастрофічної ситуації або мінімізації її наслідків. Наприклад, під час виконання польотного завдання у літака В-52Н було відірвано кіль. Для забезпечення бічної стійкості екіпаж миттєво випустив усі стояки шасі. Літак виконав безпечну аварійну посадку. Реконфігурація цілі керування - вибір оптимального варіанта польоту серед можливих альтернатив з урахуванням критичності пошкоджень зовнішніх обводів ПК. Наприклад, повернення на аеродром зльоту, пошук відповідного запасного аеродрому, а також оцінка можливості забезпечення аварійної посадки ПК на цьому аеродромі або пошук місця виконання екстреної посадки. Ключовою особливістю пропонованої концепції є те, що автоматизована система реконфігурації керування ПК розглядається, як багатоконтурна система каскадної структури з трьома рівнями керування. Модуль реконфігурації формує нові керувальні впливи для парирування, а в разі неможливості повного парирування впливу ОС – максимально можливе зниження його наслідків

focusing on the case of Korea's abnormal precipitation in the summer of 2020

Thesis(Master) -- KDI School: Master of Public Management, 2022Climate change and urbanization are accelerating the seriousness of urban flooding. Urban flooding is caused by a combination of urban characteristics, drainage systems, and land-use status. Preventive measures are important in terms of the fact that disasters in urban areas cause enormous human and property damages, and that the cost of restoration exceeds the amount of damage. This paper aims to contribute to improving city’s responsiveness to urban floods by investigating major causes of and suggesting improvement measures to urban flooding. It discusses a framework that highlights the three stages of disaster management (i.e., pre-, during, and post-disaster), including each stage’s main activities required and the importance of feedback systems across the stages. Using this framework, a case of urban flooding that took place in the summer of 2020 in Korea, which was recorded the longest rainy season in the country, was analyzed. Through the analysis, two main problems were identified: First, the capacity of urban flood defense facilities may be fundamentally insufficient due to abnormal precipitation exceeding expectations. Each time a rainfall record is updated, a flexible design standard should be prepared that comprehensively considers the climate, topography, and land-use status rather than unconditionally raising the design standard. Second, the response system to urban floods that occur repeatedly every year is unsatisfactory. Starting with the linkage of information distributed among each institution, the information system should be used as a means, not a purpose.1. Introduction 2. Current status and the causes of urban flooding 3. Research design 4. The case of urban flooding in the summer of 2020 in Korea 5. Proposals for improvement 6. ConclusionmasterpublishedHyo-Sung KI

Reconfiguring passenger ship internal environment for damage stability enhancement

The traditional risk control option adopted in naval architecture to meet safety-related objectives is by regulations, targeting damage limitation, nominally instigated in the wake of maritime accidents claiming heavy loss of life. These primarily concern the introduction of watertight bulkheads, i.e., permanent (passive) reconfiguration of the internal ship environment to enhance damage stability. This has been the most common measure, manifesting itself in the wake of every serious flooding accident since the beginning, back in the 19th century. However, traditional flooding protection through watertight subdivision, to an extent dictated by IMO regulations, has a physical limit which, if exceeded, a safety plateau is reached. This is currently the case and with damage stability standards progressively increasing, the safety gap between existing and new ships is dangerously widening and with design stability margins progressively eroding, stability management is unsustainable, leading to loss of earnings at best. The need for managing the residual risk through active intervention/protection over the life-cycle of the vessel drives industry to searching and adopting a new normal. This new normal is the innovation being explained in this paper by addressing safety enchantment through a systematic reconfiguration of the ship environment for passive and active protection in flooding accidents. In this respect, the "design-optimal" internal arrangement of a vessel, is adapted and reconfigured, using passive and active containment systems for flooding incidents, in the form of high-expansion foam products. The innovation is briefly explained, claiming transformational reduction in flooding risk in the most cost-effective way available. To support wider understanding and appreciation for the latter, the paper critically reviews the whole evolution of internal ship space reconfiguration, chronologically and systematically, concluding that new technological developments and breakthroughs will bring sustainable changes to the traditional evolutionary maritime safety enhancement

Aircraft Loss-of-Control Accident Prevention: Switching Control of the GTM Aircraft with Elevator Jam Failures

Switching control, servomechanism, and H2 control theory are used to provide a practical and easy-to-implement solution for the actuator jam problem. A jammed actuator not only causes a reduction of control authority, but also creates a persistent disturbance with uncertain amplitude. The longitudinal dynamics model of the NASA GTM UAV is employed to demonstrate that a single fixed reconfigured controller design based on the proposed approach is capable of accommodating an elevator jam failure with arbitrary jam position as long as the thrust control has enough control authority. This paper is a first step towards solving a more comprehensive in-flight loss-of-control accident prevention problem that involves multiple actuator failures, structure damages, unanticipated faults, and nonlinear upset regime recovery, etc

A review for solar panel fire accident prevention in large-scale PV applications

Due to the wide applications of solar photovoltaic (PV) technology, safe operation and maintenance of the installed solar panels become more critical as there are potential menaces such as hot spot effects and DC arcs, which may cause fire accidents to the solar panels. In order to minimize the risks of fire accidents in large scale applications of solar panels, this review focuses on the latest techniques for reducing hot spot effects and DC arcs. The risk mitigation solutions mainly focus on two aspects: structure reconfiguration and faulty diagnosis algorithm. The first is to reduce the hot spot effect by adjusting the space between two PV modules in a PV array or relocate some PV modules. The second is to detect the DC arc fault before it causes fire. There are three types of arc detection techniques, including physical analysis, neural network analysis, and wavelet detection analysis. Through these detection methods, the faulty PV cells can be found in a timely manner thereby reducing the risk of PV fire. Based on the review, some precautions to prevent solar panel related fire accidents in large-scale solar PV plants that are located adjacent to residential and commercial areas

Decision Support for Dynamic Barrier Management for Offshore Operations

PresentationEffective safety barrier management is a fundamental principle for prevention and mitigation of major accidents in offshore drilling and production operations. Barrier management methods such as bow tie diagrams are commonly used for identifying safety barriers in the development of safety case documentation and the performance of major accident risk assessments. In addition to such applications for establishing design baselines for offshore installations, some organizations are taking safety barrier management into the operational regime by establishing measures for assessing barrier health and assigning barrier owners to ensure that barriers are continuously maintained. The next step in effective safety barrier management is to develop and implement methods to continuously monitor barriers in real time and provide decision guidance for operations, maintenance, and management personnel regarding actions to be taken when barriers are degraded or failed. A systematic approach has been developed by DNV GL for identifying information requirements for dynamic barrier management, instrumentation or other sources of data for providing that information, decision criteria for determining when barriers are degraded or failed, and guidance for actions to be taken to restore degraded barriers and to prevent major accidents and mitigate their consequences. The resulting information framework can be used to support communication, consensus, decision making and action across technical disciplines and organizational boundaries. This paper summarizes the approach for the development of decision support tools for dynamic barrier management, and insights gained from application of the approach to offshore production and drilling operations with multiple industry partners. In addition, the paper summarizes industry research and development activities that are needed for effective implementation of dynamic barrier management in the offshore oil and gas industry