Calibration and Validation of A Shared space Model: A Case Study

Shared space is an innovative streetscape design that seeks minimum separation between vehicle traffic and pedestrians. Urban design is moving toward space sharing as a means of increasing the community texture of street surroundings. Its unique features aim to balance priorities and allow cars and pedestrians to coexist harmoniously without the need to dictate behavior. There is, however, a need for a simulation tool to model future shared space schemes and to help judge whether they might represent suitable alternatives to traditional street layouts. This paper builds on the authors’ previously published work in which a shared space microscopic mixed traffic model based on the social force model (SFM) was presented, calibrated, and evaluated with data from the shared space link typology of New Road in Brighton, United Kingdom. Here, the goal is to explore the transferability of the authors’ model to a similar shared space typology and investigate the effect of flow and ratio of traffic modes. Data recorded from the shared space scheme of Exhibition Road, London, were collected and analyzed. The flow and speed of cars and segregation between pedestrians and cars are greater on Exhibition Road than on New Road. The rule-based SFM for shared space modeling is calibrated and validated with the real data. On the basis of the results, it can be concluded that shared space schemes are context dependent and that factors such as the infrastructural design of the environment and the flow and speed of pedestrians and vehicles affect the willingness to share space

Modelling shared space users via rule-based social force model

The promotion of space sharing in order to raise the quality of community living and safety of street surroundings is increasingly accepted feature of modern urban design. In this context, the development of a shared space simulation tool is essential in helping determine whether particular shared space schemes are suitable alternatives to traditional street layouts. A simulation tool that enables urban designers to visualise pedestrians and cars trajectories, extract flow and density relation in a new shared space design and achieve solutions for optimal design features before implementation. This paper presents a three-layered microscopic mathematical model which is capable of representing the behaviour of pedestrians and vehicles in shared space layouts and it is implemented in a traffic simulation tool. The top layer calculates route maps based on static obstacles in the environment. It plans the shortest path towards agents' respective destinations by generating one or more intermediate targets. In the second layer, the Social Force Model (SFM) is modified and extended for mixed traffic to produce feasible trajectories. Since vehicle movements are not as flexible as pedestrian movements, velocity angle constraints are included for vehicles. The conflicts described in the third layer are resolved by rule-based constraints for shared space users. An optimisation algorithm is applied to determine the interaction parameters of the force-based model for shared space users using empirical data. This new three-layer microscopic model can be used to simulate shared space environments and assess, for example, new street designs

Methotrexate hepatotoxicity in patients with rheumatoid arthritis.

BACKGROUND Increases in aminotransferases (transaminitis) are potential major adverse reactions seen with long-term use of methotrexate (MTX). The aim of this study, therefore was to evaluate the incidence of MTX induced hepatotoxicity and its risk factors among rheumatoid arthritis (RA) patients. METHODS This retrospective study described 286 patients with RA who received ≥ 7.5 mg MTX weekly in an academic rheumatology clinic over a 15 year period. The results of serial liver function tests, concurrent MTX dose, cumulative dose and use of hepatotoxic drugs were collected and statistically analyzed according to a consecutive elevation in aminotransferases which occurred over at least a two week interval. RESULTS During the study period, 286 patients (84.4% female) with mean age of 46.6±12.7 years (18-84 years) were enrolled. Transaminitis occurred among 23.7% of patients (incidence: 6.9 per 100 person-years) during 40.5±34.6 month's exposure to MTX (989.6 person-years). The time difference between onset of therapy and occurrence of transaminitis was 22.1±22.0 months. The only significant factor related to the occurrence of transaminitis was the duration of MTX therapy. The average duration of treatment among patients with transaminitis (59.6±42.3 months) was greater than those with no transaminitis (p<0.001). The cumulative dose of MTX was significantly related to the occurrence of transaminitis (p<0.001). CONCLUSION MTX hepatotoxicity is a common complication of long-term treatment with MTX. It is associated with mild liver enzyme elevation and related to the duration of therapy

Modelling Social Interaction between Humans and Service Robots in Large Public Spaces

With the advent of service robots in public places (e.g., in airports and shopping malls), understanding socio-psychological interactions between humans and robots is of paramount importance. On the one hand, traditional robotic navigation systems consider humans and robots as moving obstacles and focus on the problem of real-time collision avoidance in Human-Robot Interaction (HRI) using mathematical models. On the other hand, the behavior of a robot has been determined with respect to a human. Parameters for human-human interaction have been assumed and applied to interactions involving robots. One major limitation is the lack of sufficient data for calibration and validation procedures. This paper models, calibrates and validates the socio-psychological interaction of the human in HRIs among crowds. The mathematical model is an extension of the Social Force Model for crowd modelling. The proposed model is calibrated and validated using open source datasets (including uninstructed human trajectories) from the Asia and Pacific Trade Center shopping mall in Osaka (Japan).In summary, the results of the calibration and validation on the multiple HRIs encountered in the datasets show that humans react to a service robot to a higher extend within a larger distance compared to the interaction range towards another human. This microscopic model, calibration and validation framework can be used to simulate HRI between service robots and humans, predict humans' behavior, conduct comparative studies, and gain insights into safe and comfortable human-robot relationships from the human's perspective

Developing and evaluating a coordinated person-based signal control paradigm in a corridor network

Connected Vehicles (CVs) provide both vehicle trajectory data and occupancy information to the junction controller, which make person-based signal controls to be possible by realizing the importance of reducing person delay. This study presents a coordinated person-based signal control algorithm (C-PBC), which has extended a previously developed approach from isolated junctions to multiple junctions. C-PBC incorporates vehicle information that is outside the CV communication range from the adjacent junction. It also updates data inputs for signal optimization algorithms based on formulated different arrival vehicle trajectory situations and coordinated data supplement algorithms. The developed algorithm has been evaluated using simulation with benchmarking signal control methods under a variety of scenarios involving CV penetration rates and predictive horizons. The results indicate that C-PBC is able to significantly improve person delay reduction when compared with fixed time control and vehicle-based control using CV data in 100% CV penetration rate under saturated flow conditions

Adaptive Person Based Signal Control System in Isolated Connected Vehicle Junction

Urban person delay and congestion have becoming an increasing important issues. Connected vehicle (CV) technologies offer opportunities for managing urban traffic efficiently to reduce vehicle delays. The adaptive signal controls in CV environments are vehicle based controls, ignoring the importance of reducing person delay and improving person mobility in urban areas. This paper proposes an innovative Adaptive Person Based Signal Control Algorithm (APBSCA) to minimize person delay at isolated urbans. APBSCA is able to explore flexible phase combinations and stage sequences to find optimal signal timing solutions in certain prediction horizon. The vehicle in formation including positions, speeds and occupancy levels are collected through CV technology as data sources. A three-level dynamic programming approach is adopted in APBSCA to update the predictive departure time of every vehicle surrounding junctions, which is affected by network environments and signal decisions. APBSCA figures out optimal signal timing parameters that yield highest person delay saving values indicators at isolated junction over the prediction period and implement the corresponding signal timings. The results indicate that APBSCA have better results in reducing average person delay in vehicle in terms of high occupancy vehicles. APBSCA offers significantly average person delay reduction up to 55%. The proposed APBSCA indicates that person based controls have potential benefits in reducing person delay to consistent the future urban goals of improving perso

A multi-objective GA-based optimisation for holistic Manufacturing, transportation and Assembly of precast construction

Resource scheduling of construction proposals allows project managers to assess resource requirements, provide costs and analyse potential delays. The Manufacturing, transportation and Assembly (MtA) sectors of precast construction projects are strongly linked, but considered separately during the scheduling phase. However, it is important to evaluate the cost and time impacts of consequential decisions from manufacturing up to assembly. In this paper, a multi-objective Genetic Algorithm-based (GA-based) searching technique is proposed to solve unified MtA resource scheduling problems (which are equivalent to extended Flexible Job Shop Scheduling Problems). To the best of the authors' knowledge, this is the first time that a GA-based optimisation approach is applied to a holistic MtA problem with the aim of minimising time and cost while maximising safety. The model is evaluated and compared to other exact and non-exact models using instances from the literature and scenarios inspired from real precast constructions

Multimodal Magnetic Resonance and Near-Infrared-Fluorescent Imaging of Intraperitoneal Ovarian Cancer Using a Dual-Mode-Dual-Gadolinium Liposomal Contrast Agent.

The degree of tumor removal at surgery is a major factor in predicting outcome for ovarian cancer. A single multimodality agent that can be used with magnetic resonance (MR) for staging and pre-surgical planning, and with optical imaging to aid surgical removal of tumors, would present a new paradigm for ovarian cancer. We assessed whether a dual-mode, dual-Gadolinium (DM-Dual-Gd-ICG) contrast agent can be used to visualize ovarian tumors in the peritoneal cavity by multimodal MR and near infra-red imaging (NIR). Intraperitoneal ovarian tumors (Hey-A8 or OVCAR3) in mice enhanced on MR two days after intravenous DM-Dual Gd-ICG injection compared to controls (SNR, CNR, p < 0.05, n = 6). As seen on open abdomen and excised tumors views and confirmed by optical radiant efficiency measurement, Hey-A8 or OVCAR3 tumors from animals injected with DM-Dual Gd-ICG had increased fluorescence (p < 0.05, n = 6). This suggests clinical potential to localize ovarian tumors by MR for staging and surgical planning, and, by NIR at surgery for resection