GraalSqueak

Embedded systems pose unique challenges to Java application developers and virtual machine designers. Chief among these challenges is the memory footprint of both the virtual machine and the applications that run within it. With the rapidly increasing set of features provided by the Java language, virtual machine designers are often forced to build custom implementations that make various tradeoffs between the footprint of the virtual machine and the subset of the Java language and class libraries that are supported. In this paper, we present the ExoVM, a system in which an application is initialized in a fully featured virtual machine, and then the code, data, and virtual machine features necessary to execute it are packaged into a binary image. Key to this process is feature analysis, a technique for computing the reachable code and data of a Java program and its implementation inside the VM simultaneously. The ExoVM reduces the need to develop customized embedded virtual machines by reusing a single VM infrastructure and automatically eliding the implementation of unused Java features on a per-program basis. We present a constraint-based instantiation of the analysis technique, an implementation in IBM's J9 Java VM, experiments evaluating our technique for the EEMBC benchmark suite, and some discussion of the individual costs of some of Java's features. Our evaluation shows that our system can reduce the non-heap memory allocation of the virtual machine by as much as 75%. We discuss VM and language design decisions that our work shows are important in targeting embedded systems, supporting the long-term goal of a common VM infrastructure spanning from motes to large servers.

BackgroundDespite the increased risk of cervical cancer (CC) among women living with HIV (WLHIV), CC screening and treatment (CCST) rates remain low in Africa. The integration of CCST services into established HIV programs in Africa can improve CC prevention and control. However, the paucity of evidence on effective implementation strategies (IS) has limited the success of integration in many countries. In this study, we seek to identify effective IS to enhance the integration of CCST services into existing HIV programs in Nigeria.MethodsOur proposed study has formative and experimental activities across the four phases of the Exploration, Preparation, Implementation, and Sustainment (EPIS) framework. Through an implementation mapping conducted with stakeholders in the exploration phase, we identified a core package of IS (Core) and an enhanced package of IS (Core+) mostly selected from the Expert Recommendations for Implementing Change. In the preparation phase, we refined and tailored the Core and Core+ IS with the implementation resource teams for local appropriateness. In the implementation phase, we will conduct a cluster-randomized hybrid type III trial to assess the comparative effectiveness of Core versus Core+. HIV comprehensive treatment sites (k = 12) will be matched by region and randomized to Core or Core+ in the ratio of 1:1 stratified by region. In the sustainment phase, we will assess the sustainment of CCST at each site. The study outcomes will be assessed using RE-AIM: reach (screening rate), adoption (uptake of IS by study sites), IS fidelity (degree to which the IS occurred according to protocol), clinical intervention fidelity (delivery of CC screening, onsite treatment, and referral according to protocol), clinical effectiveness (posttreatment screen negative), and sustainment (continued integrated CCST service delivery). Additionally, we will descriptively explore potential mechanisms, including organizational readiness, implementation climate, CCST self-efficacy, and implementation intentions.DiscussionThe assessment of IS to increase CCST rates is consistent with the global plan of eliminating CC as a public health threat by 2030. Our study will identify a set of evidence-based IS for low-income settings to integrate evidence-based CCST interventions into routine HIV care in order to improve the health and life expectancy of WLHIV.Trial registrationProspectively registered on November 7, 2023, at ClinicalTrials.gov no. NCT06128304. https://classic.clinicaltrials.gov/ct2/show/study/NCT06128304

Safepoints are a virtual machine mechanism that allows one thread to suspend other threads in a known state so that runtime actions can be performed without interruption and with data structures in a consistent state. Many virtual machines use safepoints as a mechanism to provide services such as stop-the-world garbage collection, debugging, and modification to running code such as installing or replacing classes. Languages implemented on these virtual machines may have access to these services, but not directly to the safepoint mechanism itself. We show that safepoints have many useful applications for the implementation of guest languages running on a virtual machine. We describe an API for using safepoints in languages that were implemented under the Truffle language implementation framework on the Java Virtual Machine and show several applications of the API to implement useful guest-language functionality. We present an efficient implementation of this API, when running in combination with the Graal dynamic compiler. We also demonstrate that our safepoints cause zero overhead with respect to peak performance and statistically insignificant overhead with respect to compilation time. We compare this to other techniques that could be used to implement the same functionality and demonstrate the large overhead that they incur.

Pre-exposure prophylaxis (PrEP) use is low among Black same gender-loving men (BSGLM) in Mecklenburg County, NC, an Ending the HIV Epidemic priority jurisdiction. We created PrEP-MECK-an investigator partnership among a community-based organization representative, a PrEP provider, and researchers-and conducted iterative preparation research to identify determinants of PrEP uptake and implementation strategies to address them. We first established the PrEP-MECK Coalition of community stakeholders. Next, informed by PrEP-MECK Coalition input and PRECEDE-PROCEED's educational/ecological assessment phase, we conducted focus group discussions with BSGLM not using PrEP and in-depth interviews with BSGLM who were currently or had previously taken PrEP to describe determinants and suggest implementation strategies. Based on interim findings, we partnered with clinics participating in the Mecklenburg County PrEP Initiative, which offers free PrEP services to uninsured individuals. We also conducted Consolidated Framework for Implementation Research-informed organizational assessments with community-based organizations and clinics to assess readiness to pilot the implementation strategies. We conducted 4 focus group discussions, 17 in-depth interviews, and 6 assessments. BSGLM were aware of PrEP yet perceived that costs made it unattainable. Awareness of how to access PrEP and the Mecklenburg County PrEP Initiative was lacking, and clinic scheduling barriers and provider mistrust limited access. We identified client-level implementation strategies, primarily focusing on engaging the consumer, to increase comfort with and awareness of how to access PrEP, and clinic-level implementation strategies focusing on changing clinic infrastructure, to make PrEP access easier. We plan to evaluate implementation of these strategies once fully developed to determine their acceptability and other outcomes in future research.

Virtual machines emulating hardware devices are generally implemented in low-level languages and using a low-level style for performance reasons. This trend results in largely difficult to understand, difficult to extend and unmaintainable systems. As new general techniques for virtual machines arise, it gets harder to incorporate or test these techniques because of early design and optimization decisions. In this paper we show how such decisions can be postponed to later phases by separating virtual machine implementation issues from the high-level machine-specific model. We construct compact models of whole-system VMs in a high-level language, which exclude all low-level implementation details. We use the pluggable translation toolchain PyPy to translate those models to executables. During the translation process, the toolchain reintroduces the VM implementation and optimization details for specific target platforms. As a case study we implement an executable model of a hardware gaming device. We show that our approach to VM building increases understandability, maintainability and extendability while preserving performance.

Virtual machines raise the abstraction level of the execution environment at the cost of restricting the set of supported languages. Moreover, the ability of a language implementation to integrate with other languages hosted on the same virtual machine typically constrains the features of the language. In this paper, we present a highly flexible yet efficient approach to hosting multiple programming languages on an objectoriented virtual machine. Our approach is based on extending the interface of each class with language-specific wrapper methods, offering each language a tailored view of a given class. This approach can be deployed both on a statically typed virtual machine, such as the JVM, and on a dynamic virtual machine, such as a Smalltalk virtual machine. We have implemented our approach to language interoperability on top of a prototype virtual machine for embedded systems based on the Smalltalk object model, which provides interoperability for embedded versions of the Smalltalk, Java, and BETA programming languages. (Less)

BackgroundHealth equity intervention implementation (which promotes positive health outcomes for populations experiencing disproportionately worse health) is often impeded by health-equity-specific barriers like provider bias; few studies demonstrate how to overcome these barriers through implementation strategies. An urgent health equity problem in the U.S. is the mental health of transgender youth. To address this, we developed Gender-Affirming Psychotherapy (GAP), a health equity intervention comprising best-practice mental health care for transgender youth. This paper details the identification of implementation determinants and the development of targeted strategies to promote provider adoption of GAP.MethodsThis study represents part of a larger study of mental health provider adoption of GAP. Here we describe the first 2 stages of the 3-stage community-engaged and human-centered design process – Discover, Design/Build, and Test – to identify implementation determinants of adoption and develop implementation strategies with transgender youth, their parents, and mental health providers. This process involved collecting data via focus groups, design meetings, usability testing, and champion meetings. Data were analyzed using rapid and conventional content analysis. Qualitative coding of implementation determinants was guided by the Health Equity Implementation Framework, and implementation strategy coding was facilitated by the ERIC Implementation Strategy Compilation.ResultsWe identified 15 determinants of GAP adoption, and all were specific to the transgender population (e.g., inclusive record system, anti-transgender attitudes). Seventeen implementation strategies were recommended and 12 were developed, collectively addressing all identified determinants. Most strategies were packaged into an online self-paced mental health provider training (implementation intervention) with 6 training tools. Additional inner-setting strategies were designed to support training uptake (e.g., mandate training) and GAP adoption (e.g., change record system).ConclusionsCommunity-engaged and human-centered design methods can identify health equity intervention implementation determinants and develop targeted strategies. We highlight five generalizable takeaways for health equity implementation scientists: (1) implementer bias may be a key barrier, (2) experience with the health equity population may be an important facilitator, (3) stakeholder stories may be an effective training tool, (4) inner-setting-level implementation strategies may be necessary, and (5) teaching implementers how to build implementation strategies can overcome resource-constraints.Trial registrationNovember 11, 2022; NCT05626231.Supplementary InformationThe online version contains supplementary material available at 10.1186/s43058-025-00809-7.

Assessment of implementation strategies adopted for antimicrobial stewardship interventions in long-term care facilities: a systematic review

Evidence-based nursing is widely recognized as the critical foundation for quality care. To develop a middle-range theory on the process of evidence-based nursing implementation in Chinese context. A grounded theory study using unstructured in-depth individual interviews was conducted with 56 participants who were involved in 24 evidence-based nursing implementation projects in Mainland China from September 2015 to September 2016. A middle-range grounded theory of 'Taking Root' was developed. The theory describes the evidence implementation process consisting of four components (driving forces, process, outcome, sustainment/regression), three approaches (top-down, bottom-up and outside-in), four implementation strategies (patient-centred, nurses at the heart of change, reaching agreement, collaboration) and two patterns (transformational and adaptive implementation). Certain perspectives may have not been captured, as the retrospective nature of the interviewing technique did not allow for 'real-time' assessment of the actual implementation process. The transferability of the findings requires further exploration as few participants with negative experiences were recruited. This is the first study that explored evidence-based implementation process, strategies, approaches and patterns in the Chinese nursing practice context to inform international nursing and health policymaking. The theory of Taking Root described various approaches to evidence implementation and how the implementation can be transformational for the nurses and the setting in which they work. Nursing educators, managers and researchers should work together to improve nurses' readiness for evidence implementation. Healthcare systems need to optimize internal mechanisms and external collaborations to promote nursing practice in line with evidence and achieve clinical outcomes and sustainability.

Efficient support of dynamic inheritance for class- and prototype-based languages

The purpose of this study was to complete a scoping review of implementation science (IS) research in communication sciences and disorders (CSD) over time and to determine characteristics of IS research in CSD. A scoping review was conducted of PubMed and Education Resources Information Center for sources published in English that (a) included CSD practitioners, (b) addressed IS research, and (c) identified a specific evidence-based practice. Resulting sources were systematically examined for study aim, patient populations, implementation framework utilized, setting of the study, implementation strategy examined, and implementation outcome measured. The majority of the 82 studies that underwent a full-text review (80.5%) were published in 2014 or later. One fourth of the studies were concept papers, and another one fourth focused on context assessment (25.6% of studies, each), 11% focused on designing implementation strategies, and 36.6% focused on testing implementation strategies. The patient population most frequently represented aphasia (21.3%), and most studies (34.4%) were conducted in inpatient medical settings. Nearly half (42.6%) of the nonconcept studies lacked an IS framework. Among implementation strategies identified, approximately one third of studies focused on education and/or training plus another strategy and one fourth focused on education and/or training alone. Implementation outcomes measured typically represented early stages of implementation. This scoping review of IS research in CSD described the landscape of IS studies in CSD. IS is intersecting with CSD at a rapid rate, especially since 2014. Future IS research in CSD should adopt an implementation framework a priori and consider the broad range of implementation strategies and outcomes to support the uptake of research into typical practice settings.

Many of today’s programming languages are broken. Poor performance, lack of features and hard-to-reason-about semantics can cost dearly in software maintenance and inecient execution. The problem is only getting worse with programming languages proliferating and hardware becoming more complicated. An important reason for this brokenness is that much of language design is implementation-driven. The diculties in implementation and insucient understanding of concepts bake bad designs into the language itself. Concurrency, architectural details and garbage collection are three fundamental concerns that contribute much to the complexities of implementing managed languages. We propose the micro virtual machine, a thin abstraction designed specifically to relieve implementers of managed languages of the most fundamental implementation challenges that currently impede good design. The micro virtual machine targets abstractions over memory (garbage collection), architecture (compiler backend), and concurrency. We motivate the micro virtual machine and give an account of the design and initial experience of a concrete instance, which we call Mu, built over a two year period. Our goal is to remove an important barrier to performant and semantically sound managed language design and implementation.

Despite hotels pursuing sustainability through the adoption of green practices, how the adoption is implemented has not attracted much research attention. Thus, this study explores the implementation strategies employed by city hotels in Kenya in their adoption of green practices, and assesses the relationship between the implementation strategies and the achievement of sustainability in the hotels as the study objectives. A representative sample of 87 three to five-star hotels in the then four major cities in Kenya was drawn using a multi-stage cluster sampling technique. Primary data were collected from 132 hotel departmental heads and 69 operations managers using a self-administered questionnaire and an interview schedule. The study found that the hotels were non-committal (M = 3.40) on the implementation strategies that they used in the adoption of green practices because they lacked awareness of their importance and guidance on execution. Further, the results showed that a 27.5% variation in the achievement of sustainability is due to the employment of implementation strategies. Utilisation of implementation strategies enhances sustainability in the hotel by 0.176 units. This is significant as it implies that for any hotel to achieve sustainability through the adoption of green practices, the implementation approach is key.

Hardware/software co-design and (re)configurable computing with field programmable gate arrays (FPGAs) are used to create a highly efficient implementation of the Java virtual machine (JVM). Guidelines are provided for applying a general hardware/software co-design process to virtual machines, as are algorithms for context switching between the hardware and software partitions. The advantages of using co-design as an implementation approach for virtual machines are assessed using several benchmarks applied to the implemented co-design of the JVM. It is shown that significant performance improvements are achievable with appropriate architectural and co-design choices. The co-designed JVM could be a cost-effective solution for use in situations where the usual methods of virtual machine acceleration are inappropriate.

The textbook provides a coherent overview of the key principles and current trends in the field of cloud computing. The first part outlines its historical evolution and explains the technical concepts of each cloud system. It gradually introduces the essential building blocks needed to understand cloud computing as a whole (covering virtualization concepts, virtual machines and hypervisors, container-based virtualization, and the basics of virtual networking and virtual storage). Building on this foundation, it presents the concepts of cloud technologies, including service delivery models (e.g. Infrastructure as a Service, Platform as a Service, and Software as a Service) and cloud deployment types (e.g. private, public, hybrid, and multi-cloud). The second part focuses on approaches that currently shape modern cloud-native systems, such as microservice architectures, serverless and event-driven computing, edge computing, and infrastructure as code. The textbook emphasizes motivation, intuitive explanations, and practical connections, including a discussion of trade-offs along with design decisions associated with the presented approaches. Keywords: cloud computing, virtualization, virtual machines, containers, virtual networks, virtual storage, microservices, serverless computing, edge computing, infrastructure as code.