Roll-out Process Research Articles

Achieving Air Pollution Control Targets with Technology‑Aided Monitoring: Better Enforcement or Localized Efforts?

Weak enforcement of environmental regulations remains a global issue due to inadequate monitoring and misaligned incentives. This paper examines the effects of automated monitoring on achieving air pollution control targets amidst China’s war on pollution. Utilizing the staggered rollout process and remote-sensing data, we find local governments respond to the advanced monitoring system by strategically targeting areas near monitors, resulting in a 3.2 percent decrease in pollution adjacent to automated monitors compared to areas farther away. Furthermore, we observe heterogeneity in response across cities with varying degrees of preexisting data manipulation and among officials facing different incentives and public pressure. (JEL O13, O18, P25, P28, Q53, Q55, R11)

Psychosocial determinants of parents’ intention to support reproductive health education in Ghana

ABSTRACT Promoting sex education is key to addressing the adverse sexual health outcomes among adolescents. The successful adoption and implementation of Reproductive Health Education (RHE) in schools depends on the support of curriculum owners and other stakeholders such as parents. The study explored socio-demographic and psychosocial factors influencing parents’ intentions to support the adoption and implementation of RHE in primary and high schools in Ghana. A cross-sectional survey was conducted with 387 (Mean age = 43.6 years) parents in the Upper East region of Ghana. Pearson’s correlation and regression analyses were used to examine socio-demographic and psychosocial factors influencing the stated intention to support the adoption and implementation of RHE in schools. Parent’s intention was best predicted by descriptive norms (β = .24, p < .001), and injunctive norms (β = .20, p < .001) towards supporting RHE. Other factors that predicted intention to support were beliefs about the outcomes of teaching both abstinence-only education and RHE. The findings point to the need to involve and gain support from religious leaders in the development and roll-out processes of RHE programmes. Moreover, they highlight the need for effective RHE programmes with the potential to yield positive sexual and reproductive health outcomes among adolescents and young people.

Strengthening and utilizing response groups for emergencies flagship: a narrative review of the roll out process and lessons from the first year of implementation.

The World Health Organization Regional Office for Africa (WHO/AFRO) faces members who encounter annual disease epidemics and natural disasters that necessitate immediate deployment and a trained health workforce to respond. The gaps in this regard, further exposed by the COVID-19 pandemic, led to conceptualizing the Strengthening and Utilizing Response Group for Emergencies (SURGE) flagship in 2021. This study aimed to present the experience of the WHO/AFRO in the stepwise roll-out process and the outcome, as well as to elucidate the lessons learned across the pilot countries throughout the first year of implementation. The details of the roll-out process and outcome were obtained through information and data extraction from planning and operational documents, while further anonymized feedback on various thematic areas was received from stakeholders through key informant interviews with 60 core actors using open-ended questionnaires. In total, 15 out of the 47 countries in WHO/AFRO are currently implementing the initiative, with a total of 1,278 trained and validated African Volunteers Health Corps-Strengthening and Utilizing Response Groups for Emergencies (AVoHC-SURGE) members in the first year. The Democratic Republic of Congo (DRC) has the highest number (214) of trained AVoHC-SURGE members. The high level of advocacy, the multi-sectoral-disciplinary approach in the selection process, the adoption of the one-health approach, and the uniqueness of the training methodology are among the best practices applauded by the respondents. At the same time, financial constraints were the most reported challenge, with ongoing strategies to resolve them as required. Six countries, namely Botswana, Mauritania, Niger, Rwanda, Tanzania, and Togo, have started benefiting from their trained AVoHC-SURGE members locally, while responders from Botswana and Rwanda were deployed internationally to curtail the recent outbreaks of cholera in Malawi and Kenya.

Essay x-ray: using an in-house academic writing tool to scaffold academic skills support

This paper introduces a project to develop a digital academic writing tool at Leeds Beckett University (LBU). Essay X-ray is an interactive online tool designed to help students get to grips with the structure and style of academic writing and was developed using the Articulate Storyline 360 platform. The aim was to expand LBU’s academic skills support for students tasked with essay assignments, especially at Level 4, enabling independent learning using a self-paced format available open access and 24/7. This would complement existing academic skills provision (one-to-ones, workshops, drop-ins, static online resources), with the interactive element facilitating active, hands-on learning (Lumpkin, Achen and Dodd, 2015). Following a successful development, review and rollout process, the utility of Essay X-ray as an independent learning tool but also as a classroom resource was reported by students and colleagues. Tentative talks about additional versions (Dissertation X-ray, Report X-ray) have taken place, indicating its potential for rollout to other subject areas and assessment types. Finally, in-house digital academic skills tools like Essay X-ray are posited as a potential response to the recent upsurge in Generative Artificial Intelligence (GenAI) tools. Essay X-ray requires users to think critically about essay structure, style and content to create their own original pieces of writing, thus responding to questions about the maintenance of academic integrity in a digital world. These features enable users to develop their essay writing skills, in contrast to passive engagement with a GenAI programme that merely writes an answer for them.

What’s in my fuel tank? Insights into beliefs and preferences for e-fuels and biofuels

BackgroundAlternative fuels made from biomass or CO2 and water using renewable energy can reduce CO2 and pollutant emissions compared to fossil-based mobility and thus support a transition to a more sustainable transport. The adoption of alternative fuels in transport will ultimately depend on public acceptance and drivers’ willingness to use them. Little is known if and under which circumstances people would accept alternative fuels and which narratives and cognitive beliefs might underlie these usage intentions. Moreover, it is unclear if and how laypeople distinguish between different alternative fuel types in their perceptions, e.g., between fuels made from biomass (biofuels) and fuels produced using electricity (e-fuels). To address the research gap, this study empirically investigated laypeople’s beliefs and expectations towards alternative fuels and preferences for different fuel types. Understanding preferences for fuel types could help in steering public information, support managerial decisions and communication pathways, and promote the roll-out process of fuel innovations.ResultsLaypeople expected alternative fuels to be made using renewable feedstocks and to not contain gasoline or diesel. Whereas alternative fuels were believed to have advantages concerning environmental and toxic effects and safety compared to diesel and gasoline, they were associated with practical disadvantages for drivers. It was shown that although e-fuels and biofuels both fall under the definition of ”alternative fuels”, laypeople distinguish between them in evaluations of safety, costs, and resource competitiveness: E-fuels were preferred over biofuels and believed to have a lower competition for resources than biofuels. They were also evaluated to be more expensive and comparably less safe to use. Moreover, different adopter groups were identified for both fuels.ConclusionsThe study has highlighted both adoption drivers and barriers for alternative fuels: Reduced environmental impact could be an important positive factor. In contrast, drawbacks feared by laypeople regarding a low range and an expensive fuel price could be barriers for alternative fuel adoption because they reflect current technical challenges for these fuels. Thus, a more cost-efficient production and higher fuel efficiency should be considered in an acceptance-optimized alternative fuel production.

A self-learning Monte Carlo tree search algorithm for robot path planning.

This paper proposes a self-learning Monte Carlo tree search algorithm (SL-MCTS), which has the ability to continuously improve its problem-solving ability in single-player scenarios. SL-MCTS combines the MCTS algorithm with a two-branch neural network (PV-Network). The MCTS architecture can balance the search for exploration and exploitation. PV-Network replaces the rollout process of MCTS and predicts the promising search direction and the value of nodes, which increases the MCTS convergence speed and search efficiency. The paper proposes an effective method to assess the trajectory of the current model during the self-learning process by comparing the performance of the current model with that of its best-performing historical model. Additionally, this method can encourage SL-MCTS to generate optimal solutions during the self-learning process. We evaluate the performance of SL-MCTS on the robot path planning scenario. The experimental results show that the performance of SL-MCTS is far superior to the traditional MCTS and single-player MCTS algorithms in terms of path quality and time consumption, especially its time consumption is half less than that of the traditional MCTS algorithms. SL-MCTS also performs comparably to other iterative-based search algorithms designed specifically for path planning tasks.

A fuzzy control method with the optimized intelligent weight function for directional control during aircraft autoland rollout

Aircraft landing rollout process is a complex and high non-linearity process. The mutual effects of tire dynamics, aerodynamics and multi-body dynamics should be taken into considerations. It is difficult to be accurately expressed in mathematics. Aiming at obtaining a good directional control capability during aircraft autoland rollout, a comprehensive simulation system was constructed including all those three aspects above, and a fuzzy control method with intelligent weight function was adopted which is appropriate for systems difficult to be modeled exactly. In the paper’s work, the intelligent weight function was optimized by the power function for the first time. By adjusting the exponential k, the fuzzy control rules can be conveniently and reasonably optimized. Through a set of simulations without crosswind, the optimal k was obtained. Finally, the simulation tests under conditions of 20 kn crosswind with ±5° original drift angles were conducted with the system configured by the optimal k. Accroding to the results, the optimized fuzzy controller can give a good directional control performance.

Models as Agents: Optimizing Multi-Step Predictions of Interactive Local Models in Model-Based Multi-Agent Reinforcement Learning

Research in model-based reinforcement learning has made significant progress in recent years. Compared to single-agent settings, the exponential dimension growth of the joint state-action space in multi-agent systems dramatically increases the complexity of the environment dynamics, which makes it infeasible to learn an accurate global model and thus necessitates the use of agent-wise local models. However, during multi-step model rollouts, the prediction of one local model can affect the predictions of other local models in the next step. As a result, local prediction errors can be propagated to other localities and eventually give rise to considerably large global errors. Furthermore, since the models are generally used to predict for multiple steps, simply minimizing one-step prediction errors regardless of their long-term effect on other models may further aggravate the propagation of local errors. To this end, we propose Models as AGents (MAG), a multi-agent model optimization framework that reversely treats the local models as multi-step decision making agents and the current policies as the dynamics during the model rollout process. In this way, the local models are able to consider the multi-step mutual affect between each other before making predictions. Theoretically, we show that the objective of MAG is approximately equivalent to maximizing a lower bound of the true environment return. Experiments on the challenging StarCraft II benchmark demonstrate the effectiveness of MAG.

Roll-Out Deployment Process Analysis of a Fiber Reinforced Polymer (FRP) Composite Tape-Spring Boom.

Deployable extendable booms are widely used in aerospace technology due to many advantages they have, such as high folded-ratio, lightweight and self-deployable properties. A bistable FRP composite boom can not only extend its tip outwards with a corresponding rotation speed on the hub, but can also drive the hub rolling outwards with a fixed boom tip, which is commonly called roll-out deployment. In a bistable boom's roll-out deployment process, the second stability can keep the coiled section from chaos without introducing a controlling mechanism. Because of this, the boom's roll-out deployment velocity is not under control, and a high moving speed at the end will give the structure a big impact. Therefore, predicting the velocity in this whole deployment process is necessary to be researched. This paper aims to analyze the roll-out deployment process of a bistable FRP composite tape-spring boom. First, based on the Classical Laminate Theory, a dynamic analytical model of a bistable boom is established through the energy method. Afterwards, an experiment is introduced to produce some practical verification for comparison with the analytical results. According to the comparison with the experiment, the analytical model is verified for predicting the deployment velocity when the boom is relatively short, which can cover most booms using CubeSats. Finally, a parametric study reveals the relationship between the boom properties and the deployment behaviors. The research of this paper will give some guidance to the design of a composite roll-out deployable boom.

The Telemedicine Experience in Primary Care Practices in the United States: Insights From Practice Leaders.

The need to rapidly implement telemedicine in primary care during the coronavirus disease 2019 (COVID-19) pandemic was addressed differently by various practices. Using qualitative data from semistructured interviews with primary care practice leaders, we aimed to report commonly shared experiences and unique perspectives regarding telemedicine implementation and evolution/maturation since March 2020. We administered a semistructured, 25-minute, virtual interview with 25 primary care practice leaders from 2 health systems in 2 states (New York and Florida) included in PCORnet, the Patient-Centered Outcomes Research Institute clinical research network. Questions were guided by 3 frameworks (health information technology evaluation, access to care, and health information technology life cycle) and involved practice leaders' perspectives on the process of telemedicine implementation in their practice, with a specific focus on the process of maturation and facilitators/barriers. Two researchers conducted inductive coding of qualitative data open-ended questions to identify common themes. Transcripts were electronically generated by virtual platform software. Twenty-five interviews were administered for practice leaders representing 87 primary care practices in 2 states. We identified the following 4 major themes: (1) the ease of telemedicine adoption depended on both patients' and clinicians' prior experience using virtual health platforms, (2) regulation of telemedicine varied across states and differentially affected the rollout processes, (3) visit triage rules were unclear, and (4) there were positive and negative effects of telemedicine on clinicians and patients. Practice leaders identified several challenges to telemedicine implementation and highlighted 2 areas, including telemedicine visit triage guidelines and telemedicine-specific staffing and scheduling protocols, for improvement.

Managing two-dose COVID-19 vaccine rollouts with limited supply: Operations strategies for distributing time-sensitive resources.

Distributing scarce resources such as COVID‐19 vaccines is often a highly time‐sensitive and mission‐critical operation. Our research was prompted by a significant obstacle that the United States and other nations encountered during the early months of the COVID‐19 vaccination campaign: Most COVID‐19 vaccines require two doses given 3 or 4 weeks apart. Given the severely limited supply and mounting pressure on many countries to reduce hospitalizations and mortality, how to effectively roll out two‐dose vaccines was a critical policy decision. In this paper, we first model and analyze inventory dynamics of the rollout process under three rollout strategies: (1) holding back second doses, (2) releasing second doses, and (3) stretching the lead time between doses. Then we develop an SEIR (susceptible, exposed, infectious, recovered) model that incorporates COVID‐19 asymptomatic and symptomatic infections to evaluate these strategies in terms of infections, hospitalizations, and mortality. Among our findings, we show releasing second doses reduces infections but creates uneven vaccination patterns. In addition, to ensure second doses are given on time without holding back inventory, strictly less than half of the supply can be allocated to first‐dose appointments. Stretching the between‐dose lead time flattens the infection curve and reduces both hospitalizations and mortality compared with the strategy of releasing second doses. We also consider an alternative single‐dose vaccine with lower efficacy and show that the vaccine can be more effective than its two‐dose counterparts in reducing infections and mortality. We conduct extensive sensitivity analyses related to age composition, risk‐based prioritization, supply disruptions, and disease transmissibility. Our paper provides important implications for policymakers to develop effective vaccine rollout strategies in developed and developing countries alike. More broadly, our paper sheds light on how to develop effective operations strategies for distributing time‐sensitive resources in times of crisis.

Rollout of the Oral Health Literacy Toolkit in California: A Mixed-Methods Analysis

Background: Formative assessment of the rollout process of the California Oral Health Literacy (OHL) toolkit uses a mixed-methods approach. The OHL toolkit is an educational resource for dental professionals to improve communication with patients. This study was intended to obtain user feedback and suggestions for improvement.Methods: This mixed-methods assessment of the OHL toolkit rollout included anonymous post-training surveys distributed at regional dental societies in California and 1:1 interviews with dental champions who would work with the research team on toolkit rollout. Anonymous and deidentified data were analyzed using R and Dedoose.Results: From surveys (n = 37), the OHL toolkit components of highest interest to respondents were teach-back, increasing health literacy awareness among staff and learning to use plain language communication. Perceived implementation barriers were time constraints, insufficient staffing and a need for more training on communication techniques. Impressions, implementation prospects and recommendations for the OHL toolkit were obtained from qualitative interviews (n = 6). Overall, participants had positive impressions of the training presentation, OHL toolkit and implementation prospects.Conclusion: This study identified interest areas and implementation barriers, data that can be used to further improve the OHL toolkit and reduce barriers faced by practitioners. Further assessments at clinician and patient levels will be helpful for outcomes evaluation.Practical implications: The OHL toolkit is perceived positively by dental practitioners in California. Facilitators and barriers identified by dental providers and champions can be addressed through changes to the OHL toolkit and training. Rollout at the national level is being considered.

Implications of Learn Not To Burn (LNTB) Program from the National Fire Protection Agency in the United States

Burn is one of the serious injuries for all age groups however the younger the age is, the seriousness of the damage is larger. Children are vulnerable to burn injuries however the current Korean fire prevention content and education curriculum for children do not have specific burn prevention content. This paper is to examine the Learn Not To Burn (LNTB) program at the National Fire Protection Agency (NFPA) in the United States and aims to extract implications towards the burn prevention program for children in Korea. In order to do so, we investigated the LNTB contents, compositions from LNTB textbooks, and LNTB teaching materials. Further, the development and operational process to maintain the LNTB content and the rollout process are also investigated. We also investigated the burn-related content and curriculum of the fire prevention from an elementary school in Korea. We extracted the implications from the LNTB program and described the need for burn prevention education for young children in Korea. Finally, we made suggestions for creating the LNTB program in Korea by collaborating with stakeholders for young children.

An Assessment of Healthcare Relationship Trust between Patent Medicine Vendors and Residents of Hard-to-Reach Settlements in Northern Nigeria

A trusting relationship is required for effective communication between care providers and care seekers, and trust is a determinant of early healthcare-seeking and care outcomes. The patient-Doctor healthcare trust relationship has been widely studied in different settings. However, there is a dearth of information on whether the factors underlying healthcare relationship trust between patients and their doctors are the same as those underlying patients’ trust in other healthcare professionals (including the PPMVs). This study, therefore, aims to assess the level and determinants of healthcare relationship trust between patent medicine vendors and their clients in hard-to-reach settlements in North-western Nigeria. We adapted the revised healthcare relationship trust scale, administered by trained data collectors using android devices. The data were analysed using Stata (version 16). We used the Chi-square test to identify the correlates of the level of trust(high/low), and binary logistic regression was used to identify its determinants. Statistical significance was defined as P&lt;0.05. Slightly above one-quarter (28.1%) of the underserved had high healthcare relationship trust in the PPMVs. Being married, male, residing in a rented or makeshift shelter in Kaduna state, with under-five child(ren) in their household, and self-reporting good health predicted a high level of healthcare relationship trust in PPMVs among the underserved who participated in this study. We concluded that the personal and household characteristics of the underserved could significantly influence their level of trust in PPMV. Therefore, to achieve the aim of improving health outcomes in deprived populations, initiatives seeking to integrate PPMVs into the formal health system in resource-constrained settings should seek to address the determinants of healthcare relationship trust in these populations as part of their rollout process. Keywords: Communities, Hard-to-reach, Healthcare, Trust, Relationship, Workforce.

Accelerated Protection (AP) scheme in overhead distribution networks

It is a new philosophy of protection in distribution networks, whose objective is to reduce, in an unconventional way, the sum of the operating times (exposure) of the protection equipment (reclosers and circuit breakers) on the short-circuit currents, while throughout the automatic reclosing cycle, maintaining the coordination of the protection system. From the protection point of view, this philosophy can be applied mainly in feeders that contain a large number of protection devices in series, which results in long operating times and exposure to fault currents, especially in devices further upstream in the feeders, with using conventional protection philosophies. Pilots of this new philosophy were applied, which presented satisfactory and even surprising results (in cases of broken cables), thus, resulting in a roll-out process of this philosophy in about 400 other devices protection in the utility grid, presenting good scalability due to possibility of its application in all models of IEDs of reclosers and circuit breakers of the utility that are found on the market. This scheme was elaborated and managed through the project called Urban Futurability, which consists of an R&amp;D project performed at Enel-SP.

Recursive Least Squares Based Refinement Network for Vehicle Trajectory Prediction

Trajectory prediction of surrounding objects plays a pivotal role in the field of autonomous driving vehicles. In the current rollout process, it suffers from an accumulation of errors, which has a negative impact on prediction accuracy. This paper proposes a parametric-learning recursive least-squares (RLS) method integrated with an encoder–decoder framework for trajectory prediction, named the recursive least-squares-based refinement network (RRN). Through the generation of several anchors in the future trajectory, RRN can capture both local and global motion patterns. We conducted experiments on the prevalent NGSIM and INTERACTION datasets, which contain various scenarios such as highways, intersections and roundabouts. The promising results indicate that RRN could improve the performance of the rollout trajectory prediction effectively.

COVID-19 vaccine website accessibility dashboard

BackgroundThe COVID-19 pandemic has exacerbated historical inequities for people with disabilities including barriers in accessing online information and healthcare appointment websites. These barriers were brought to the foreground during the vaccine rollout and registration process. ObjectiveThis cross-sectional study aimed to examine accessibility of U.S. state and territory COVID-19 information and registration centralized websites. MethodsThe Johns Hopkins Disability Health Research Center created a COVID-19 Vaccine Dashboard compiling COVID-19 information and vaccine registration web pages from 56 states and territories in the United States (U.S.) reviewed between March 30 through April 5, 2021 and analyzed accessibility using WAVE Web Accessibility Evaluation Tool (WAVE). WAVE identifies website accessibility barriers, including insufficient contrast, alternative text, unlabeled buttons, total number of errors, and error density. Web pages were ranked and grouped into three groups by number of errors, creating comparisons between states on accessibility barriers for people with disabilities. ResultsAll 56 U.S states and territories had COVID-19 information web pages and 29 states had centralized state vaccine registration web pages. Total errors, error density, and alert data were utilized to generate accessibility scores for each web page, the median score was 259 (range = 14 to 536 and IQR = 237) for information pages, and 146 (range = 10 to 281 and IQR = 105) for registration pages. ConclusionsThese results highlight barriers people with disabilities may encounter when accessing information and registering for the COVID-19 vaccine, which underscore inequities in the pandemic response for the disability community and elevate the need to prioritize accessibility of public health information.

Converting the existing disease surveillance from a paper-based to an electronic-based system using district health information system (DHIS-2) for real-time information: the Lebanese experience

IntroductionThe Ministry of Public Health in Lebanon is in the process of converting the surveillance reporting from a cumbersome paper-based system to a web-based electronic platform (DHIS-2) to have real-time information for early detection of alerts and outbreaks and for initiating a prompt response.ObjectivesThis paper aimed to document the Lebanese experience in implementing DHIS-2 for the disease surveillance system. It also targets to assess the improvement of reporting rates and timeliness of the reported data and to disclose the encountered challenges and opportunities.MethodologyThis is a retrospective description of processes involved in the implementation of the DHIS-2 tool in Lebanon. Initially, it was piloted for the school-based surveillance in 2014; then its use was extended in May 2017 to cover other specific surveillance systems. This included all surveillance programs collecting aggregate data from hospitals, medical centers, dispensaries, or laboratories at the first stage. As part of the national roll-out process, the online application was developed. The customized aggregated-based datasets, organization units, user accounts, specific and generic dashboards were generated. More than 80 training sessions were conducted throughout the country targeting 1290 end-users including health officers at the national and provincial levels, focal persons who were working in all public and private hospitals, laboratories, and medical centers as well. Completeness and timeliness of reported data were compared before and after the implementation of DHIS-2. The unveiled challenges and the main lessons learned during the roll-out process were discussed.ResultsFor laboratory-based surveillance, completeness of reporting increased from 70.8% in May to 89.6% in October. Timeliness has improved from 25 to 74%. For medical centers, an improvement of 8.1% for completeness and 9.4% in timeliness was recorded before and after training sessions. For zero reporting, completeness remains the same (88%) and timeliness has improved from 74 to 87%. The main challenges faced during the implementation of DHIS-2 were mainly infrastructural and system-related in addition to poor internet connectivity, limited workforce, and frequent changes to DHIS-2 versions.ConclusionImplementation of DHIS-2 improved timeliness and completeness for aggregated data reporting. Continued on-site support, monitoring, and system enhancement are needed to improve the performance of DHIS-2.

South Africa’s Response to COVID-19: Realities and Challenges of the Vaccination Roll-Out Process

Abstract The paper provides a critical analysis of the South African government’s economic response to the COVID-19 crisis and the current roll-out of vaccinations in South Africa. In preparation for the vaccination roll-out, South Africa set up national strategic committees to facilitate the smooth distribution of the vaccination process. However, despite being one of the first African countries to receive the vaccines, the effective roll-out is still ranked low. The paper used qualitative descriptive analysis to discuss the strategies promoting community understanding and limiting vaccination misinformation. The findings project that the government must deliver an effective and protected vaccine to reduce morbidity and mortality from COVID-19. However, the mere accessibility of a vaccine is not enough to secure extensive immunological security; the immunisation must be accepted by all stakeholders and the public in the country. Vaccine uncertainty is a primary impediment to vaccine acceptance and the achievement of people’s immunity, which is mandatory to protect the marginalised populations in the country. The paper concludes that various strategic efforts made by the South Africa government to deal with the disease and the roll-out of vaccination in responding to COVID-19 remains a significant challenge. It then recommends that there should be a coordinated approach by both government and stakeholders to ensure effective distribution and reduce the COVID-19 vaccine hesitancy in the country.

Effects of landing gear layout on the safe rollout envelope of equipped–skid aircraft

Rollout is an inevitable phase of realizing horizontal landing for an equipped–skid aircraft; therefore, one should pay attention to the safety of the entire rollout process. The research presented herein analyzes the effects of the landing gear layout on the safe rollout envelope, which is the set of all states where the aircraft can remain in the desired state region during the entire rollout phase. First, the nonlinear reachability analysis and its internal relation with a safe envelope are briefly described. To improve the calculation efficiency of approximating the safe envelope, a mixed implicit explicit (MIE) scheme is introduced. Subsequently, a simple yet accurate model of nonlinear aircraft dynamics is established and the dangerous state region during the rollout phase is defined. Finally, based on the numerical results, the effects of the layout type on the safe envelope are discussed. In addition, a reasonable safety evaluation index is proposed to quantitatively analyze the effects of position parameters on the rollout safety. The results indicate that with the application of the variable friction skid, the safe envelope of the wheel–skid aircraft is larger than that of the all–skid aircraft. Compared with the original position parameters, the optimized values increase the rollout safety of the wheel–skid aircraft by 4.18%.