Network Buffer Research Articles

A comparison of different clustering algorithms for the project time buffering problem

This paper studies the decentralised time buffering problem (TBP) to absorb project risk by building sufficient buffers with the aim of obtaining a stable project schedule. First, the position of the buffers in the project network should be determined and, subsequently, each buffer must be optimally sized. We investigate different activity clustering methods (K-means, rank order, criticality-based and network clustering) to determine the ideal groups of activities to be clustered together and protected by an allocated buffer. The obtained clusters of activities are then inputted in a multi-population multi-factorial evolutionary algorithm (MPMFEA) for creating buffers based on the characteristics of the activities in each cluster. To the best of our knowledge, this is the first study to integrate existing clustering methods into a buffering algorithm in order to optimise the project stability. Previous studies hybridising both methods use a single clustering algorithm (e.g. K-means) that does not use the same information than the buffering algorithm or require more complex (simulation-based) buffering methods. The computational experiments on a large set of artificial instances validate the effectiveness of the proposed MPMFEA for solving the TBP, especially in combination with the network clustering method. Although the generic K-Means method is still considered a viable option for clustering, the more pragmatic clustering methods are more effective. We inform project managers that considering precedence relations between activities during clustering is crucial, but mimicking this behaviour in all clustering methods does not guarantee successful protection of their projects.

When does greener mean slimmer? Longitudinal analysis of green space, trees, grass, and body mass index in a cohort of 50,672 Australians: Exploring potential non-linearities and modifying influences of household relocation and gender

Studies of associations between green space and overweight/obesity are often agnostic to green space type and potential contingencies by gender and household relocation. We investigated associations between total green space, tree canopy, and open grass within 1.6 km road network buffers, on body mass index (BMI) at baseline (n = 110,234; 2005–2009) and follow-up (n=50,672; 2012–2015) using data from the Sax’s Institute’s 45 and Up Study (NSW, Australia). Analyses considered potential non-linearities in these associations and the possibility for effect modification by gender and household relocation. Models were adjusted for age, couple status, region of birth, household income, employment status, educational attainment and housing status. Results revealed that 20 % or more tree canopy, compared to 0–10 % tree canopy was associated with lower BMI. Comparable findings were not observed for open grass or total green space. Nonlinear associations were observed, with a rapid decrease in odds of being overweight/obese at baseline with 20 % tree canopy, that became more stable by 30 % tree canopy. This non-linearity was stronger in females than males. By follow-up, associations indicated potential protective effects with 20 % or more tree canopy for overweight/obesity in females. Logistic regression models examined the odds of becoming a healthy weight at follow-up in overweight/obese individuals at baseline. Results indicated a potentially protective influence of tree canopy on overweight/obesity for people who did not move home (odds ratio (OR) = 1.06, 95 % confidence interval (CI) = 1.01–1.12), but not those who relocated (OR = 0.97, 95 % CI = 0.83–1.11). In sum, conserving and restoring urban tree canopy to at least 20% to 30% of nearby land-use may help to reduce levels of overweight and obesity in the community These benefits may be particularly potent for females and for people who are residentially stable. More open grass, or green space in general, may not have the same benefits for adult overweight/obesity as tree canopy.

Associations between the neighbourhood food environment and food and drink purchasing in England during lockdown: A repeated cross-sectional analysis.

Evidence for the effect of neighbourhood food environment (NFE) exposures on diet in the UK is mixed, potentially due to exposure misclassification. This study used the first national COVID-19 lockdown in England as an opportunity to isolate the independent effects of the NFE exposure on food and drink purchasing, and assessed whether these varied by region. Transaction-level purchasing data for food and drink items for at-home (1,221 households) and out-of-home consumption (171 individuals) were available from the GB Kantar Fast Moving Consumer Goods Panel for London and the North of England. The study period included 23rd March to 10th May 2020 ('lockdown'), and the same period in 2019 for comparison. NFE exposures included food outlet density and proximity, and NFE composition within a 1 km network buffer around the home. Associations were estimated for both years separately, adjusted for individual and household characteristics, population density and area deprivation. Interaction terms between region and exposures were explored. There were no consistent patterns of association between NFE exposures and food and drink purchasing in either time period. In 2019, there was some evidence for a 1.4% decrease in energy purchased from ultra-processed foods for each additional 500 m in the distance to the nearest OOH outlet (IR 0.986, 95% CI 0.977 to 0.995, p = 0.020). In 2020, there was some evidence for a 1.8% reduction in total take-home energy for each additional chain supermarket per km2 in the neighbourhood (IR 0.982, 95% CI 0.969, 0.995, p = 0.045). Region-specific effects were observed in 2019 only. Findings suggest that the differences in exposure to the NFE may not explain differences in the patterns or healthiness of grocery purchasing. Observed pre-pandemic region-specific effects allude to the importance of geographical context when designing research and policy. Future research may assess associations for those who relied on their NFE during lockdown.

Synergistic modulation of hydrogen bond network reconstruction and pH buffering of electrolyte enables highly reversible Zn anode

Utilizing aqueous electrolytes offers zinc-ion batteries (ZIBs) with inherent safety, high ionic conductivity, and power density, which is promising for energy storage applications. While the H2O-induced problems including hydrogen evolution reaction (HER) and the accumulation of by-products hinder the electrochemical performance of ZIBs. Herein, proline is used as an electrolyte additive to solve the above issues. Density functional theory (DFT) calculation and experimental results confirm that abundant hydrogen bonds (HBs) are formed between proline and H2O, disrupting the original HB network to inhibit HER kinetics. Meanwhile, as an amphoteric compound, proline neutralizes the OH− generated by HER, preventing it to react with Zn2+ and SO42− to form insulating by-products. Consequently, the Zn||Zn symmetric cell reaches the cycle life of 5500 h at 1.0 mA cm−2, 1.0 mAh cm−2, and 660 h at 10 mA cm−2, 5.0 mAh cm−2. When matching with the VO2 cathode, the Zn||VO2 cell achieves a capacity retention of 68.25 % at 5.0 A g−1 after 6694 cycles. This work provides a novel perspective integrating the regulation of the HB network and pH buffer chemistry to develop advanced aqueous electrolytes.

Longitudinal study of changes in greenness exposure, physical activity and sedentary behavior in the ORISCAV-LUX cohort study

BackgroundGreenness exposure has been associated with many health benefits, for example through the pathway of providing opportunities for physical activity (PA). Beside the limited body of longitudinal research, most studies overlook to what extent different types of greenness exposures may be associated with varying levels of PA and sedentary behavior (SB). In this study, we investigated associations of greenness characterized by density, diversity and vegetation type with self-reported PA and SB over a 9-year period, using data from the ORISCAV-LUX study (2007–2017, n = 628).MethodsThe International Physical Activity Questionnaire (IPAQ) short form was used to collect PA and SB outcomes. PA was expressed as MET-minutes/week and log-transformed, and SB was expressed as sitting time in minutes/day.Geographic Information Systems (ArcGIS Pro, ArcMap) were used to collect the following exposure variables: Tree Cover Density (TCD), Soil-adjusted Vegetation Index (SAVI), and Green Land Use Mix (GLUM). The exposure variables were derived from publicly available sources using remote sensing and cartographic resources. Greenness exposure was calculated within 1000m street network buffers around participants’ exact residential address.ResultsUsing Random Effects Within-Between (REWB) models, we found evidence of negative within-individual associations of TCD with PA (β = − 2.60, 95% CI − 4.75; − 0.44), and negative between-individual associations of GLUM and PA (β = − 2.02, 95% CI − 3.73; − 0.32). There was no evidence for significant associations between greenness exposure and SB. Significant interaction effects by sex were present for the associations between TCD and both PA and SB. Neighborhood socioeconomic status (NSES) did not modify the effect of greenness exposure on PA and SB in the 1000 m buffer.DiscussionOur results showed that the relationship between greenness exposure and PA depended on the type of greenness measure used, which stresses the need for the use of more diverse and complementary greenness measures in future research. Tree vegetation and greenness diversity, and changes therein, appeared to relate to PA, with distinct effects among men and women. Replication studies are needed to confirm the relevance of using different greenness measures to understand its’ different associations with PA and SB.

Examination of multidimensional geographic mobility and sexual behaviour among Black cisgender sexually minoritized men in Chicago.

Black sexually minoritized men (BSMM) are the most likely to acquire HIV in Chicago- a racially segregated city where their daily travel may confer different HIV-related risks. From survey and GPS data among participants of the Neighbourhoods and Networks Cohort Study, we examined spatial (proportion of total activity space away from home), temporal (proportion of total GPS points away from home), and motivation-specific (discordance between residential and frequented sex or socializing neighbourhoods) dimensions of mobility. To identify potential drivers of BSMM's risk, we then examined associations between mobility and sexual behaviours known to cause HIV transmission: condomless anal sex, condomless anal sex with a casual partner, transactional sex, group sex, and sex-drug use. Multivariable logistic regression models assessed associations. Of 269 cisgender BSMM, most were 20-29 years old, identified as gay, and lowincome. On average, 96.9% (Standard Deviation: 3.7%) of participants' activity space and 53.9% (Standard Deviation: 38.1%) of participants' GPS points occurred outside their 800m home network buffer. After covariate adjustment, those who reported sex away from home were twice as likely to report condomless sex (Odds Ratio: 2.02, [95% Confidence Interval (CI): 1.08, 3.78]). Those who reported socializing away from home were four times more likely to have condomless sex with a casual partner (Odds Ratio: 4.16 [CI: 0.99, 29.0]). BSMM are on the move in Chicago, but only motivation-specific mobility may increase HIV transmission risk. Multidimensional investigations of mobility can inform place-based strategies for HIV service delivery.

MEDUSA: A Dynamic Codec Switching Approach in HTTP Adaptive Streaming

HTTP Adaptive Streaming (HAS) solutions utilize various Adaptive BitRate (ABR) algorithms to dynamically select appropriate video representations, aiming to adapt to fluctuations in network bandwidth. However, current ABR implementations have a limitation in that they are designed to function with one set of video representations, i.e. , the bitrate ladder, which differ in bitrate and resolution, but are encoded with the same video codec. When multiple codecs are available, current ABR algorithms select one of them prior to the streaming session and stick to it throughout the entire streaming session. Although newer codecs are generally preferred over older ones, their compression efficiencies differ depending on the content’s complexity, which varies over time. Therefore, it is necessary to select the appropriate codec for each video segment to reduce the requested data while delivering the highest possible quality. In this paper, we first provide a practical example where we compare compression efficiencies of different codecs on a set of video sequences. Based on this analysis, we formulate the optimization problem of selecting the appropriate codec for each user and video segment (on a per-segment basis in the outmost case), refining the selection of the ABR algorithms by exploiting key metrics, such as the perceived segment quality and size. Subsequently, to address the scalability issues of this centralized model, we introduce a novel distributed plug-in ABR algorithm for Video on Demand (VoD) applications called MEDUSA to be deployed on top of existing ABR algorithms. MEDUSA enhances the user’s Quality of Experience (QoE) by utilizing a multi-objective function that considers the quality and size of video segments when selecting the next representation. Using quality information and segment size from the modified Media Presentation Description (MPD) , MEDUSA utilizes buffer occupancy to prioritize quality or size by assigning specific weights in the objective function. To show the impact of MEDUSA, we compare the proposed plug-in approach on top of state-of-the-art techniques with their original implementations and analyze the results for different network traces, video content, and buffer capacities. According to the experimental findings, MEDUSA shows the ability to improve QoE for various test videos and scenarios. The results reveal an impressive improvement in the QoE score of up to 42% according to the ITU-T P.1203 model (mode 0). Additionally, MEDUSA can reduce the transmitted data volume by up to more than 40% achieving a QoE similar to the techniques compared, reducing the burden on streaming service providers for delivery costs.

Exploring Spatial Accessibility to Urban Activities Based on the Transit-Oriented Development Concept in Pathum Thani, Thailand

Transit-oriented development (TOD) serves as a model for sustainable urban planning, integrating land use and transport planning. Successful implementation varies across specific geographic locations and has yet to be fully realized in the suburban areas of Thailand. This study empirically examined and searched for understanding of the enhanced accessibility to urban activities through the TOD concept by focusing on bus stops and rail mass transit. The study utilized a network buffer zone approach around transit areas as TOD measurement units, examining distances of 500 m, 1000 m, and 2000 m. Spatial analysis was applied to examine and understand the enhanced accessibility to urban activities through TOD by using network analysis, Getis-Ord Gi* hotspot analysis, and bivariate local Moran’s I. The results revealed that this area still has limited access to activities via public transport, particularly in the areas where activities are concentrated, especially in commercial, mixed-use, and residential zones. However, upon examining the relationship between access distance and the intensity of land use activities, it became apparent that within the network buffer zone encircling the transit areas, designated as transit-oriented development (TOD) measurement units, there exists a notable concentration and diversity of land use activities. Specifically, enhanced accessibility to the transportation system corresponded to increased activity density. Nonetheless, this correlation was predominantly observed at stations situated in more central areas, whereas stations located at greater distances exhibited a lower intensity and diversity of activities within the TOD zone.

Uso misto do solo e a caminhada para fins de transporte em idosos: uma abordagem baseada em diferentes métricas do ambiente construído

Abstract The presence of land use mix (LUM) in a neighborhood has been shown as an important aspect to promote walking as a daily means of transport. However, few studies in the area have applied different measurement strategies to test their effect on alternative modes of travel behavior, such as older adults walking. We applied six LUM measures of land use mix in two neighborhood definitions (500 and 1000m network buffers) and assessed their associations with walking for transport outcomes in adults over age 60 years from the EpiFloripa Aging study, living in the municipality of Florianópolis, Brazil, in 2013/14. Accounting for sociodemographic and environmental variables, adjusted associations found a positive relationship between four LUM and walking. The entropy index and three alternative measures defined by the intensity of commercial and nonresidential uses were positively associated with the walking for transportation, regardless of neighborhood definition. Stronger positive associations were seen when using smaller buffers and measures of the proportion of commercial uses, proportion of nonresidential uses and destination density. The results show that alternative measurements can overcome the entropy index, pointing out the need to adapt LUM measures and neighborhood scale to the geographic context and age group under analysis.

Obesogenic neighborhood environment is associated with body fat and low-grade inflammation in Brazilian children: could the mother's BMI be a mediating factor?

To evaluate the direct and indirect associations of obesogenic and leptogenic neighborhood environments with body fat, and pro- and anti-inflammatory adipokines in Brazilian children. Cross-sectional study. The body fat distribution was assessed using dual-energy X-ray absorptiometry (DXA). Concentrations of leptin and adiponectin were measured. Four hundred meters (0·25 miles) road network buffer was the neighborhood unit used to assess the environmental characteristics around households. Obesogenic and leptogenic environments were the latent variables obtained from the observed characteristics. The mother's BMI, ultra-processed food consumption, and physical activity before and after school, were tested as mediating variables. A hybrid model of structural equations was used to test the direct and indirect associations of obesogenic and leptogenic environments with body fat, leptin and adiponectin concentrations. Urban area of Viçosa, Minas Gerais, Brazil. Children aged 8- and 9-years (n 367). Obesogenic environment was directly associated with the mother's BMI (β: 0·24, P = 0·02) and the child's body fat (β: 0·19, P = 0·02). The mother's BMI and body fat mediated the association of the obesogenic environment with leptin concentrations (β: 0·05, P = 0·02). Obesogenic neighborhood environment was directly associated with body fat and mother's BMI, and indirectly associated with leptin concentrations in Brazilian children, mediated by the mother's BMI and body fat.

A Visual Sensitivity Aware ABR Algorithm for DASH via Deep Reinforcement Learning

In order to cope with the fluctuation of network bandwidth and provide smooth video services, adaptive video streaming technology is proposed. In particular, the adaptive bitrate (ABR) algorithm is widely used in dynamic adaptive streaming over HTTP (DASH) to improve quality of experience (QoE). However, existing ABR algorithms still ignore the inherent visual sensitivity of human visual system (HVS). As the final receiver of video, HVS has different sensitivity to the quality distortion of different video content, and video content with high visual sensitivity needs to allocate more bitrate resources. Therefore, existing ABR algorithms still have limitations in reasonably allocating bitrate and maximizing QoE. To solve this problem, this paper designs an adaptive bitrate strategy from the perspective of user vision, studies the modeling of visual sensitivity, and proposes a visual sensitivity aware ABR algorithm. We extract a set of content features and attribute features from the video, and consider the simulation of HVS to establish a total masking effect model that reflects the visual sensitivity more accurately. Further, the network status, buffer occupancy, and visual sensitivity are comprehensively considered under a deep reinforcement learning framework to select the appropriate bitrate for maximizing QoE. We implement the proposed algorithm over a realistic trace-driven evaluation and compare its performance with several latest algorithms. Experimental results show that our algorithm can align ABR strategy with visual sensitivity to achieve better QoE in high visual sensitivity content, and improves the average perceptual video quality and overall user QoE by 18.3% and 22.8%, respectively. Additionally, we prove the feasibility of our algorithm through subjective evaluation in the real environment.

A New Approach to Clock Skewing for Area and Power Optimization of ASICs Using Differential Flipflops and Local Clocking

A new design methodology for reducing the area and power of standard cell ASICs that uses a combination of differential flipflops and a method of deliberate clock-skewing, called local clocking (LC), is described. LC introduces clock skew without the use of extra buffers in the clock network. This is done by having some flipflops, called sources, generate clock signals for other flipflops, called targets. The method involves two key features: (1) the design of a new differential flipflop, referred to as KVFF, that is functionally identical to a master-slave edgetriggered D flipflop, but in addition, produces a completion signal that is a skewed version of its input clock, which is used to clock other flipflops; and (2) an efficient algorithm that identifies the sources and targets involved in the new clocking scheme, with the objective of reducing area and power. These are reduced because deliberate skew introduces extra slack on the logic cones that feed the target flipflops, which is exploited by synthesis tools to reduce area and power. Furthermore, the area and power overhead of conventional methods of introducing skew, e.g. buffers, is eliminated. Local clocking is shown to result in significant improvements in area, power and wirelength for several, publicly available, benchmark circuits for 65nm bulk CMOS and 28nm FDSOI technologies. For 65nm, the average improvement in area, power and wirelength were 27.7%, 13.4%, and 21.0%, respectively. For 28nm FDSOI the average improvement in area, power, and wirelength were 20.0%, 10.5%, and 30.5%, respectively. In addition, the paper demonstrates how local clocking can be used to eliminate hold time violations.

Public Open Spaces and Leisure-Time Walking: A Longitudinal Study With Brazilian People in the COVID-19 Pandemic.

To examine whether changes in public open spaces (POS) were associated with leisure-time walking (LTW) between 2014 and 2021. The sample comprised a prospective cohort of individuals living in São Paulo City, Brazil. The baseline sample was collected in 2014/2015 (4042 people aged 12y or older) and the second wave in 2020/2021 (1431 people aged 18y or older, 35.4% of total). Changes in POS scores in 500-m network buffers were based on household address, including positive or negative maintenance and increases or decreases in parks, public squares, and bike paths between 2015 and 2020. The International Physical Activity Questionnaire was used to evaluate LTW in the baseline and second wave. To examine the association of LTW with changes in POS, we used multilevel models in 4 levels: health administration areas, census tracts, individuals, and observations of individuals. The exposure was the POS tertiles, and the outcome was LTW. Changes in LTW prevalence were observed in both periods and according to POS tertiles distributions. When adjusted for time (baseline/second wave), gender, education, and age, the highest POS tertile was significantly associated with a high likelihood for LTW (odds ratio = 1.44; 95% confidence interval, 1.03-2.02). The results showed that people in São Paulo who lived within 500-m buffers with the highest access to POS were more likely to practice LTW between 2014/2015 and 2020/2021. These results have important implications for policies that were implemented in 2014, including the New Master Plan to contribute to São Paulo's good ranking among healthy cities.

Deep Reinforcement Learning-Based Approach for Video Streaming: Dynamic Adaptive Video Streaming over HTTP

Dynamic adaptive video streaming over HTTP (DASH) plays a crucial role in delivering video across networks. Traditional adaptive bitrate (ABR) algorithms adjust video segment quality based on network conditions and buffer occupancy. However, these algorithms rely on fixed rules, making it challenging to achieve optimal decisions considering the overall context. In this paper, we propose a novel deep-reinforcement-learning-based approach for DASH streaming, with the primary focus of maintaining consistent perceived video quality throughout the streaming session to enhance user experience. Our approach optimizes quality of experience (QoE) by dynamically controlling the quality distance factor between consecutive video segments. We evaluate our approach through a comprehensive simulation model encompassing diverse wireless network environments and various video sequences. We also conduct a comparative analysis with state-of-the-art methods. The experimental results demonstrate significant improvements in QoE, ensuring users enjoy stable, high-quality video streaming sessions.

Inherent and adaptive resilience of logistics operations in food supply chains

AbstractThis study aims to investigate the sources of resilience for logistics operations as it relates to food supply chains and their responses during natural disasters and other disruptions. The literature tends to treat inherent and adaptive resilience as somewhat separate constructs. Thus, this study also aims to provide some insights into the relatively underexamined area of how inherent resilience synergistically works with adaptive resilience to maintain flows for food supply chains in a developing economy context. To address the research aim, two supply chain wide case studies were used to investigate the contribution of logistic activities toward the resilience of foods supply chains in two different South Asian regions. This context was selected as these regions are prone to frequent natural disruptions and other disruptions, and these food supply chains also play a crucial role in economy and providing relief supplies to their communities. Logistics operations play a key role in achieving overall supply chain resilience. The sources of inherent resilience are the network structure, buffer capacity, and strong social connections among the actors. Adaptive resilience is derived from transportation flows, storage, information sharing, and demand management processes. Surprisingly, resilience in this context is achieved despite the relatively low level of integration, an unsophisticated technological landscape and compromised logistics infrastructure. Still, resilience can be enhanced further. This study contributes to the sparse literature that examines logistics activities that influence the resilience of food supply chains in the context of natural disasters and other disruptions. Furthermore, uncovering the substructure of logistics resilience activities, and surprisingly, the synergies between inherent and adaptive resilience, adds to the emerging body of literature.

O.2.2-4 Longitudinal associations between residential greenness exposure, physical activity and sedentary behavior levels: a country-wide study in Luxembourg

Abstract Greenness exposure has been associated with many health benefits, by providing opportunities for physical activity. Longitudinal studies are lacking, and most studies overlook the varying effects of different greenness types on physical activity (PA) and sedentary behavior (SB). We investigated 9-year associations of greenness characterized by overall greenness, vegetation type, and mix, with PA and SB using data from the ORISCAV-LUX study and the MET’HOOD project. The PA and SB outcomes were measured using the International Physical Activity Questionnaire (IPAQ) short form. PA is expressed as MET-minutes/week and log-transformed, and SB is expressed as sitting time in minutes/day. The exposure variables were Tree Cover Density (TCD), Soil-adjusted Vegetation Index (SAVI), and Green Land Use Mix (GLUM). The study population consisted of 628 adults, who completed the questionnaires between January 2007-2009 and January 2016-July 2017. Missing data were imputed. Greenness exposure was collected within 800-meter street network buffers based on participants’ exact residential address. Associations between TCD, SAVI and GLUM and PA and SB were estimated using a Random Effects Within-Between (REWB) model. Interaction by gender and SES were explored. Sensitivity analyses were performed on smaller (500 meter buffer) and larger (1000, 2000 meter buffers) definitions of the residential neighborhood. We found evidence of between-individual associations of GLUM and PA (β = 0.17, 95% CI: 0.03; 0.91), and within-individual associations of TCD with PA (β = 0.03, 95% CI: 0.002; 0.438) (in 800 meter buffers). There was no evidence for associations between greenness exposure and SB. Sensitivity analysis using varying buffer sizes showed similar associations. Our study found evidence of associations of GLUM and TCD with PA, and no associations between greenness exposure and SB. Promoting different types of greenness may result in different PA levels and behaviors. Replication studies are needed to inform urban planning interventions. This study is funded by the EU Horizon2020 Program under grant agreement number 956780 (SURREAL). The ORISCAV-LUX study is funded by the Luxembourg Ministry of Health and Ministry of Higher Education and Research. The MET'HOOD project is funded by the Luxembourg National Research Fund as part of the CORE 2020 programme (C20/BM/14787166).

Inequalities in neighbourhood features within children's 20-minute neighbourhoods and variation in time spent locally, measured using GPS

There has been a growing interest in policies that encourage local living by promoting accessible and walkable communities, such as the 20-minute neighborhood concept. Despite the widespread adoption of this policy worldwide, little research has been conducted on the characteristics of children's 20-minute neighborhoods and their association with time spent locally.This study aimed to explore the features of Scottish children's 20-minute neighborhoods by analysing an 800 m road and path network buffer surrounding 687 children's homes. Based on existing literature, the study identified key features associated with children's time spent locally and the 20-minute neighborhood policy. The study then examined variations in these features by socioeconomic status, urbanicity, and gender.The findings revealed significant inequalities in the presence of health-benefiting (e.g., green spaces, recreational facilities, healthy food outlets) and health-harming (e.g., major roads, unhealthy commodity retailers) environments within children's 20-minute neighborhoods. Children from more deprived areas had access to more of both types of environments. The study also found that having a school within a 20-minute neighborhood was associated with an increased amount of time spent locally (IRR 1.62, 95% CI 1.5 to 1.8, p<0.001).The study suggests that the 20-minute neighborhood policy should extend beyond mere access to local amenities and prioritise creating healthy 20-minute neighborhoods, particularly in socioeconomically deprived areas. The research highlights the importance of promoting equal access to quality local environments, which can contribute to improved health and well-being outcomes for children.

An asymmetric graded indexed helical structured optical fibre for enhanced optical delays

Optical fibres are generally used to provide a guided path to optical signals. Optical fibres are classified as multi-mode or single-mode fibres. Multi-mode graded index (GRIN) optical fibres have been prevalent in short-range optical networks, while single-mode GRIN fibres are used for long-range links. Another potential application of optical fibre is the optical delays in numerous applications, such as quantum computing, network buffering, data synchronization, pattern correlation, etc. This paper conceptualizes a novel application of an asymmetric GRIN optical fibre for possible enhanced optical delays. An asymmetric GRIN parabolic profile with helical structure geometry has been proposed for this task. A detailed analysis has been presented to investigate the effects of various parameters of the proposed geometry. Further, a guided propagation has also been demonstrated with the help of ray optics and the Helmholtz wave equation to assess the feasibility of the proposal. The presented investigations revealed that the geometrical length of the proposed structure is significantly compact compared with the traditional GRIN fibre, proving it beneficial for optical delays.

Analysing Spatial Pattern of the Three Major Fast-Food Chain Restaurants in Johor Bahru Johor, Malaysia

Spatial analysis has proven to be an impactful tool in business for gaining insights and making informed decisions, especially in analysing spatial patterns and finding new locations for starting or expanding the business. However, most fast-food chain restaurants have t yet to optimise the use of GIS, especially in analysing the spatial distribution patterns of their outlets. This study aims to analyse the spatial distribution patterns of three major fast-food chains in Johor Bahru, Malaysia: KFC, McDonald’s, and Burger King. Four spatial analyses were performed: network analysis, buffer analysis, heatmap analysis, and spatial distribution pattern analysis using the nearest neighbour technique. The results showed different spatial distribution patterns for these three major fast-food chains. KFC is more spatially randomly distributed, concentrated in downtown Johor Bahru, while McDonald’s is spatially scattered throughout the Johor Bahru district and the Skudai area. Burger King has too few outlets and is spatially scattered in the Johor Bahru district. From these results, fast-food franchises can use the information to locate new locations based on their indicators for new outlets.

The moderating impact of neighborhood walkability on mHealth interventions to increase moderate to vigorous physical activity for insufficiently active adults in a randomized trial

BackgroundEcological models suggest that interventions targeting specific behaviors are most effective when supported by the environment. This study prospectively examined the interactions between neighborhood walkability and an mHealth intervention in a large-scale, adequately powered trial to increase moderate-to-vigorous physical activity (MVPA).MethodsHealthy, insufficiently active adults (N = 512) were recruited purposefully from census block groups ranked on walkability (high/low) and socioeconomic status (SES, high/low). Participants were block-randomized in groups of four to WalkIT Arizona, a 12-month, 2 × 2 factorial trial evaluating adaptive versus static goal setting and immediate versus delayed financial reinforcement delivered via text messages. Participants wore ActiGraph GT9X accelerometers daily for one year. After recruitment, a walkability index was calculated uniquely for every participant using a 500-m street network buffer. Generalized linear mixed-effects hurdle models tested for interactions between walkability, intervention components, and phase (baseline vs. intervention) on: (1) likelihood of any (versus no) MVPA and (2) daily MVPA minutes, after adjusting for accelerometer wear time, neighborhood SES, and calendar month. Neighborhood walkability was probed at 5th, 25th, 50th, 75th, and 95th percentiles to explore the full range of effects.ResultsAdaptive goal setting was more effective in increasing the likelihood of any MVPA and daily MVPA minutes, especially in lower walkable neighborhoods, while the magnitude of intervention effect declined as walkability increased. Immediate reinforcement showed a greater increase in any and daily MVPA compared to delayed reinforcement, especially relatively greater in higher walkable neighborhoods.ConclusionsResults partially supported the synergy hypotheses between neighborhood walkability and PA interventions and suggest the potential of tailoring interventions to individuals’ neighborhood characteristics.Trial RegistrationPreregistered at clinicaltrials.gov (NCT02717663).