42 research outputs found

    Model and Integrate Medical Resource Available Times and Relationships in Verifiably Correct Executable Medical Best Practice Guideline Models (Extended Version)

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    Improving patient care safety is an ultimate objective for medical cyber-physical systems. A recent study shows that the patients' death rate is significantly reduced by computerizing medical best practice guidelines. Recent data also show that some morbidity and mortality in emergency care are directly caused by delayed or interrupted treatment due to lack of medical resources. However, medical guidelines usually do not provide guidance on medical resource demands and how to manage potential unexpected delays in resource availability. If medical resources are temporarily unavailable, safety properties in existing executable medical guideline models may fail which may cause increased risk to patients under care. The paper presents a separately model and jointly verify (SMJV) architecture to separately model medical resource available times and relationships and jointly verify safety properties of existing medical best practice guideline models with resource models being integrated in. The SMJV architecture allows medical staff to effectively manage medical resource demands and unexpected resource availability delays during emergency care. The separated modeling approach also allows different domain professionals to make independent model modifications, facilitates the management of frequent resource availability changes, and enables resource statechart reuse in multiple medical guideline models. A simplified stroke scenario is used as a case study to investigate the effectiveness and validity of the SMJV architecture. The case study indicates that the SMJV architecture is able to identify unsafe properties caused by unexpected resource delays.Comment: full version, 12 page

    Executable clinical models for acute care

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    Medical errors are the third leading cause of death in the U.S., after heart disease and cancer, causing at least 250,000 deaths every year. These errors are often caused by slips and lapses, which include, but are not limited to delayed diagnosis, delayed or ineffective therapeutic interventions, and unintended deviation from the best practice guidelines. These situations may occur more often in acute care settings, where the staff are overloaded, under stress, and must make quick decisions based on the best available evidence. An \textit{integrated clinical guidance system} can reduce such medical errors by helping medical staff track and assess patient state more accurately and adapt the care plan according to the best practice guidelines. However, a main prerequisite for developing a guideline system is to create computer interpretable representations of the clinical knowledge. The main focus of this thesis is to develop executable clinical models for acute care. We propose an organ-centric pathophysiology-based modeling paradigm, in which we translate the medical text into executable interactive disease and organ state machines. We formally verify the correctness and safety of the developed models. Afterward, we integrate the models into a best practice guidance system. We study the cardiac arrest and sepsis case studies to demonstrate the applicability of proposed modeling paradigm. We validate the clinical correctness and usefulness of our model-driven cardiac arrest guidance system in an ACLS training class. We have also conducted a preliminary clinical simulation of our model-driven sepsis screening system

    The NASA computer science research program plan

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    A taxonomy of computer science is included, one state of the art of each of the major computer science categories is summarized. A functional breakdown of NASA programs under Aeronautics R and D, space R and T, and institutional support is also included. These areas were assessed against the computer science categories. Concurrent processing, highly reliable computing, and information management are identified

    Process Mining Handbook

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    This is an open access book. This book comprises all the single courses given as part of the First Summer School on Process Mining, PMSS 2022, which was held in Aachen, Germany, during July 4-8, 2022. This volume contains 17 chapters organized into the following topical sections: Introduction; process discovery; conformance checking; data preprocessing; process enhancement and monitoring; assorted process mining topics; industrial perspective and applications; and closing

    Securing CAN-Based Cyber-Physical Systems

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    With the exponential growth of cyber-physical systems (CPSs), new security challenges have emerged. Various vulnerabilities, threats, attacks, and controls have been introduced for the new generation of CPS. However, there lacks a systematic review of the CPS security literature. In particular, the heterogeneity of CPS components and the diversity of CPS systems have made it difficult to study the problem with one generalized model. As the first component of this dissertation, existing research on CPS security is studied and systematized under a unified framework. Smart cars, as a CPS application, were further explored under the proposed framework and new attacks are identified and addressed. The Control Area Network (CAN bus) is a prevalent serial communication protocol adopted in industrial CPS, especially in small and large vehicles, ships, planes, and even in drones, radar systems, and submarines. Unfortunately, the CAN bus was designed without any security considerations. We then propose and demonstrate a stealthy targeted Denial of Service (DoS) attack against CAN. Experimentation shows that the attack is effective and superior to attacks of the same category due to its stealthiness and ability to avoid detection from current countermeasures. Two controls are proposed to defend against various spoofing and DoS attacks on CAN. The first one aims to minimize the attack using a mechanism called ID-Hopping so that CAN arbitration IDs are randomized so an attacker would not be able to target them. ID-Hopping raises the bar for attackers by randomizing the expected patterns in a CAN network. Such randomization hinders an attacker’s ability to launch targeted DoS attacks. Based on the evaluation on the testbed, the randomization mechanism, ID-Hopping, holds a promising solution for targeted DoS, and reverse engineering CAN IDs, and which CAN networks are most vulnerable. The second countermeasure is a novel CAN firewall that aims to prevent an attacker from launching a plethora of nontraditional attacks on CAN that existing solutions do not adequately address. The firewall is placed between a potential attacker’s node and the rest of the CAN bus. Traffic is controlled bi-directionally between the main bus and the attacker’s side so that only benign traffic can pass to the main bus. This ensures that an attacker cannot arbitrarily inject malicious traffic into the main bus. Demonstration and evaluation of the attack and firewall were conducted by a bit-level analysis, i.e., “Bit banging”, of CAN’s traffic. Results show that the firewall successfully prevents the stealthy targeted DoS attack, as well as, other recent attacks. To evaluate the proposed attack and firewall, a testbed was built that consisted of BeagleBone Black and STM32 Nucleo- 144 microcontrollers to simulate real CAN traffic. Finally, a design of an Intrusion Detection System (IDS) was proposed to complement the firewall. It utilized the proposed firewall to add situational awareness capabilities to the bus’s security posture and detect and react to attacks that might bypass the firewall based on certain rules

    Chameleon: A Secure Cloud-Enabled and Queryable System with Elastic Properties

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    There are two dominant themes that have become increasingly more important in our technological society. First, the recurrent use of cloud-based solutions which provide infrastructures, computation platforms and storage as services. Secondly, the use of applicational large logs for analytics and operational monitoring in critical systems. Moreover, auditing activities, debugging of applications and inspection of events generated by errors or potential unexpected operations - including those generated as alerts by intrusion detection systems - are common situations where extensive logs must be analyzed, and easy access is required. More often than not, a part of the generated logs can be deemed as sensitive, requiring a privacy-enhancing and queryable solution. In this dissertation, our main goal is to propose a novel approach of storing encrypted critical data in an elastic and scalable cloud-based storage, focusing on handling JSONbased ciphered documents. To this end, we make use of Searchable and Homomorphic Encryption methods to allow operations on the ciphered documents. Additionally, our solution allows for the user to be near oblivious to our system’s internals, providing transparency while in use. The achieved end goal is a unified middleware system capable of providing improved system usability, privacy, and rich querying over the data. This previously mentioned objective is addressed while maintaining server-side auditable logs, allowing for searchable capabilities by the log owner or authorized users, with integrity and authenticity proofs. Our proposed solution, named Chameleon, provides rich querying facilities on ciphered data - including conjunctive keyword, ordering correlation and boolean queries - while supporting field searching and nested aggregations. The aforementioned operations allow our solution to provide data analytics upon ciphered JSON documents, using Elasticsearch as our storage and search engine.O uso recorrente de soluções baseadas em nuvem tornaram-se cada vez mais importantes na nossa sociedade. Tais soluções fornecem infraestruturas, computação e armazenamento como serviços, para alem do uso de logs volumosos de sistemas e aplicações para análise e monitoramento operacional em sistemas críticos. Atividades de auditoria, debugging de aplicações ou inspeção de eventos gerados por erros ou possíveis operações inesperadas - incluindo alertas por sistemas de detecção de intrusão - são situações comuns onde logs extensos devem ser analisados com facilidade. Frequentemente, parte dos logs gerados podem ser considerados confidenciais, exigindo uma solução que permite manter a confidencialidades dos dados durante procuras. Nesta dissertação, o principal objetivo é propor uma nova abordagem de armazenar logs críticos num armazenamento elástico e escalável baseado na cloud. A solução proposta suporta documentos JSON encriptados, fazendo uso de Searchable Encryption e métodos de criptografia homomórfica com provas de integridade e autenticação. O objetivo alcançado é um sistema de middleware unificado capaz de fornecer privacidade, integridade e autenticidade, mantendo registos auditáveis do lado do servidor e permitindo pesquisas pelo proprietário dos logs ou usuários autorizados. A solução proposta, Chameleon, visa fornecer recursos de consulta atuando em cima de dados cifrados - incluindo queries conjuntivas, de ordenação e booleanas - suportando pesquisas de campo e agregações aninhadas. As operações suportadas permitem à nossa solução suportar data analytics sobre documentos JSON cifrados, utilizando o Elasticsearch como armazenamento e motor de busca

    A system dynamics approach to health system transformation: a case study of tertiary services provision in the KwaZulu-Natal Department of Health.

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    Doctoral Degree. University of KwaZulu-Natal, Durban.When staff attrition intensifies in a flagship hospital, which has been internationally benchmarked for its best practices, then health care provision is in crisis. Hospital managers are inundated by resource constraints and challenging priorities that make excessive demands on their time, energy, leadership practice, spirit of work and motivation. These leaders are consumed by operational matters such as attending meetings, resolving human resource issues, hospital management and administrative tasks, which leave them with limited time for coordinated strategic planning, monitoring implementation of services or reflection. Consequently, systemic tension exists between policy implementation and service delivery, resulting in escalating patient and staff complaints, dissatisfaction, and medical litigation, thereby producing instability and fluctuations in the health ecosystem organizational behaviour. In examining literature which proposes the value of a systemic approach to organisational behaviour, I decided to embark on this study to apply the qualitative system dynamics (SD) approach and the complexity theory methodology. I explored the dynamic complexities in the KwaZulu Natal (KZN) health ecosystem behaviour, the underlying systemic factors and their inter-relationships, the organisational messiness, and the uncertainties and policy processes that impact on effective service delivery in the one central and three tertiary hospitals. Focus group discussions (FGD) were among the research techniques used, whereby dialogue with participants identified the variables and verified the data collected. These conversations deepened our understanding of the research gap, that is, the sustained shortage of medical specialists over time; the supply and demand of specialists in KZN hospitals, and suggested changes to workforce planning, so as to diffuse these types of tensions within managed systems. While using the SD approach, our rational systems, critical and complexity thinking around issues and simulating circumstances and organisational behaviour; multidimensional social interactions, beliefs and paradigms, all became evident. Feedback loops in causal loop diagrams (CLD) co-constructed with the FG, facilitated our visualizing the ontological context; how the elements interconnect, interact and change over time. The significance of time delays, which cause tensions in policy implementation, governance and decision-making that affect dynamic system behaviour, was apparent. The CLD identified the leverage points for a complex, all-embracing, multi-level approach to organizational transformation. I discovered, through this study, knowledge and skills to effect profound transformation in my awakened leadership practice. This research contributes to emerging literature on applying the SD approach to health care leaders becoming effective and committed to enact integral ethical health care. It recommends paradigmatic deconstruction in reductionist thinking; shifting egocentric consciousness and limiting health care practices; constructing whole systems thinking, integrated participative consciousness, and a transdisciplinary integral team approach, through awakened integral leadershi

    XR, music and neurodiversity: design and application of new mixed reality technologies that facilitate musical intervention for children with autism spectrum conditions

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    This thesis, accompanied by the practice outputs,investigates sensory integration, social interaction and creativity through a newly developed VR-musical interface designed exclusively for children with a high-functioning autism spectrum condition (ASC).The results aim to contribute to the limited expanse of literature and research surrounding Virtual Reality (VR) musical interventions and Immersive Virtual Environments (IVEs) designed to support individuals with neurodevelopmental conditions. The author has developed bespoke hardware, software and a new methodology to conduct field investigations. These outputs include a Virtual Immersive Musical Reality Intervention (ViMRI) protocol, a Supplemental Personalised, immersive Musical Experience(SPiME) programme, the Assisted Real-time Three-dimensional Immersive Musical Intervention System’ (ARTIMIS) and a bespoke (and fully configurable) ‘Creative immersive interactive Musical Software’ application (CiiMS). The outputs are each implemented within a series of institutional investigations of 18 autistic child participants. Four groups are evaluated using newly developed virtual assessment and scoring mechanisms devised exclusively from long-established rating scales. Key quantitative indicators from the datasets demonstrate consistent findings and significant improvements for individual preferences (likes), fear reduction efficacy, and social interaction. Six individual case studies present positive qualitative results demonstrating improved decision-making and sensorimotor processing. The preliminary research trials further indicate that using this virtual-reality music technology system and newly developed protocols produces notable improvements for participants with an ASC. More significantly, there is evidence that the supplemental technology facilitates a reduction in psychological anxiety and improvements in dexterity. The virtual music composition and improvisation system presented here require further extensive testing in different spheres for proof of concept
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