OV Model Research Articles

Higher expression of TSR2 aggravating hypertension via the PPAR signaling pathway.

Hypertension is a complex disease with unknown causes. Therefore, it's crucial to deeply study its molecular mechanism. The hypertension dataset was obtained from Gene Expression Omnibus data base (GEO), and miRNA regulating central hub genes was screened via weighted gene co-expression network (DEGs) and gene set enrichment (GSEA). Cell experiments validated TSR2's role and the PPAR signaling pathway through western blotting. 500 DEGs were identified for hypertension, mainly enriched in actin cross-linking, insulin signaling, PPAR signaling, and protein localization. Eight hub genes (SEC61G, SRP14, Liy AR, NIP7, SDAD1, POLR1D, DYNLL2, TSR2) were identified. Four hub genes (LYAR, SDAD1, POLR1D, TSR2) exhibited high expression levels in the hypertensive tissue samples, while showing low expression levels in the normal tissue samples. This led us to speculate that they may have relevant regulatory effects on hypertension. When TSR2 was knocked down in the hypertension peripheral blood mononuclear cells (PBMC) model, the critical proteins in the PPAR signaling pathway (FABP, PPAR, PLTP, ME1, SCD1, CYP27, FABP1, OLR1, CPT-1, PGAR, CAP, ADIPO, MMP1, UCP1, ILK, PDK1 UBC AQP7) were downregulated. This also occurred in the hypertension peripheral blood mononuclear cells (PBMC) + TSR2_ OV model. TSR2 is highly expressed in individuals with hypertension and may play a significant role in the development of hypertension through the PPAR signaling pathway. TSR2 could serve as a molecular target for the early diagnosis and precise treatment of hypertension, providing a valuable direction for the mechanism research of this condition.

Vehicle-to-vehicle cooperative driving model considering end-to-end delay of communication network

To explore the mechanism of the end-to-end transmission delay of the communication network on the collaborative driving process for traffic flow in the vehicle-to-vehicle communication environment, based on the idea of the car-following model, this paper introduces characteristic parameters characterizing the end-to-end transmission delay of the network into Newell's following model and proposes a CD and OV model by considering the time delay characteristics of the collaborative driving process from information transmission to control decision and then to physical execution. To determine the cooperative driving system's stability criterion, the stability analysis of the new model is examined. By using the reductive perturbation approach, the spatiotemporal evolution mechanism of the traffic flow around the critical stability point under the influence of various transmission delays is analyzed. The resulting modified Korteweg-de Vries (mKdV) equations and density wave solutions are derived. The results show that the end-to-end transmission delay of the network has a significant shock effect on the stability of the vehicle-vehicle cooperative driving system, and the stability of the traffic flow and the ability to suppress traffic congestion becomes worse with the increase in the end-to-end transmission delay.

Modelling the long-term consequences of implementing hormone-free reproductive management on the sustainability of a dairy sheep farm

Livestock production systems are strongly influenced by societal constraints which induce changes in their overall chain value organization. In dairy sheep farming, practices such as the male effect (ME) supported by new precision tools (heat detector) can be used to stop the use of hormonal treatments (HT) for heat induction and synchronization. However, the effectiveness of these “hormone-free” (HF) methods for managing ewes’ reproduction remains more uncertain than that of HT. Thus, introduction of HF practices in farms currently managed with HT could imply collateral impacts on the overall functioning of the production system and affect its long-term sustainability. In this work, a new multi-agent model (called REPRIN'OV) was designed to simulate consequences of introducing a HF reproduction management on a series of biotechnical, economic and environmental farm performance indicators, including farmer workload. Three reproduction management scenarios were simulated over five consecutive years for the case study of a French dairy sheep farm considered as conventional (i.e. using HT for reproduction management). They were defined as: use of HTs and insemination (HAI); no use of HTs while preserving insemination practice (HFAI); no use of HTs and direct mating only (i.e., no insemination; HFM). Results confirm that implementing HF reproductive management without accompanying it with further changes in farm management, could negatively impact several indicators of the farm sustainability in the medium and long-term. Indeed, the HF scenarios resulted in overall lower farm biotechnical performances (e.g., −4% for the fertility rate; P < 0.05) due to a more variable heat induction. An increase in farmer's workload during the lambing period (+34% and +33% of h/L of milk in HFAI and HFM, respectively; P < 0.05) was also observed, mainly due to more staggered lambing periods. As for the simulated environmental indicators, they were increased, mostly due to the reduction of the total milk production in HF’s (e.g., +6% of farm methane emissions per L of milk for both HFAI and HFM; P < 0.05). Nevertheless, positive outcomes were also simulated in the HFs as ewes lambing peaks were lower than in HAI suggesting, e.g., a possibility to improve ewes and lamb surveillance during lambing. HF scenarios also led to higher gross margin (GM) per litre of milk produced because no HT was used, reducing the production costs compare to HAI. In addition, implementing insemination in HFAI improved farm milk production and quality (i.e., fat and protein content), which resulted in improved total GM compared to HFM. Still, the reduction in the total milk production in HFs was too important compared with the improvement of the GM per litre, resulting in a reduced total GM in these scenarios (-4% and −5% in HFAI and HFM, respectively; P < 0.05). Overall, simulation results showed that to warrant sustainable introduction of HF strategies (including ME), new frameworks in the organization of key operations at the farm level should be explored (e.g., extending reproduction or milking periods length) and trade-offs should be discussed, considering all involved stakeholders of the dairy sheep industry and the chain’s value requirements. The REPRIN’OV model, may provide an effective tool to simulate the collateral impacts of establishing HF reproductive management and could be used as a decision support system to accompany the ambitious transition towards a HF dairy sheep industry in Europe and beyond.

A belief-degree based multi-objective transportation problem with multi-choice demand and supply

This paper focusses on the development of a Multi-choice Multi-objective Transportation Problem (MCMOTP) in the uncertain environment. The parameters associated with the objective functions in MCMOTP are regarded as uncertain variables and the other parameters associated with supply capacity and demand requirements are considered under the multi-choice environment. In this paper, two ranking criteria have been utilized to convert the uncertain objectives into their crisp form. Using these two ranking criteria for the uncertain MCMOTP model, two deterministic models have been developed namely, Expected Value Model (EV Model) and Optimistic Value Model (OV Model). The multi-choice parameters in the constraints are converted to a single choice parameters with the help of binary variable approach. The EV and OV models are solved directly in the LINGO 18.0 software using minimizing distance method and fuzzy programming technique. At last, a numerical illustration is provided to demonstrate the application and algorithm of the models. The sensitivity of the objective functions in OV Model is also examined with respect to the confidence levels to investigate variation in the objective functions.

Dissipation Characteristics of Vehicle Queue in V2X Environment Based on Improved Car-Following Model

In recent years, the technology of Internet of Vehicles has developed rapidly, among which vehicle to everything (V2X) technology is provided with a quite important promotion value in the intelligent transportation field. In V2X environment, the driver can receive real-time information of the motion status of adjacent vehicles and the signal duration of the intersection, and take the decision-making action of manipulating the vehicle in advance, which has a certain impact on the evolution process of queue dissipation. This paper studies the improved OV model based on V2X environment and considering the driver’s early response time selects the intersection queue dissipation efficiency as the index to analyze the intersection traffic efficiency and studies the impact of different initial headway, maximum speed, and safety distance on the intersection traffic flow. The simulation results show that compared with the traditional OV model and the OV model considering driver’s reaction delay, the model proposed in this paper greatly improves the efficiency of traffic flow recovery after green light, so the model proposed in this paper can promote the stability of traffic flow. The linear stability of the proposed model was analyzed by using the linear stability theory to obtain the stability conditions of the improved model. Furthermore, a simulation environment was established to analyze the vehicle queue dissipation at intersections and to simulate the improved V2X car-following model as well as the platoon dissipation state under different traffic parameters. The research results show that vehicle drivers can obtain traffic flow operation status in real-time through V2X equipment and change the operation of the vehicle itself in a targeted manner, which can significantly improve the safety and stability of traffic flow operation, and greatly raise the dissipation efficiency of the platoon. The method proposed in this paper can increase the queue dissipation rate and shorten the recovery time of the traffic system, respectively.

Peripherally-driven myeloid NFkB and IFN/ISG responses predict malignancy risk, survival, and immunotherapy regime in ovarian cancer

BackgroundTumors can influence peripheral immune macroenvironment, thereby creating opportunities for non-invasive serum/plasma immunobiomarkers for immunostratification and immunotherapy designing. However, current approaches for immunobiomarkers’ detection are largely quantitative, which is unreliable...

LYAPUNOV STABILITY ANALYSIS BASED ON AN IMPROVED OV MODEL.

The stability analysis of car-following model is an important content in the research process of car-following model. The stability analysis method based on an improved OV model was carried out. Different from the traditional linear stability analysis, the Lyapunov stability analysis of the improved OV car-following model was proposed from the perspective of control theory, and the theoretical derivation was given. The results show that, the stability analysis of the model using Lyapunov stability analysis method is consistent with Lyapunov theory. Therefore, the effectiveness of the Lyapunov stability analysis method is verified.

Reduced model of a reaction-diffusion system for the collective motion of camphor boats.

The unidirectional motion of a camphor boat along an annular water channel is observable. When camphor boats are placed in a water channel, both homogeneous and inhomogeneous states occur as collective motions, depending on the number of boats. The inhomogeneous state is a type of congestion, that is, the velocities of the boats change with temporal oscillation, and the shock wave appears along the line of travel of the boats. The unidirectional motion of a single camphor boat and the homogeneous state can be represented by traveling wave solutions in a mathematical model. Because the experimental results described here are thought of as a type of bifurcation phenomenon, the destabilization of traveling wave solutions may indicate the emergence of congestion. We previously attempted to study a linearized eigenvalue problem associated with a traveling wave solution. However, the problem is too difficult to analyze rigorously, even for just two camphor boats. Therefore we developed a center manifold theory and derived a reduced model in our previous work. In the present paper, we study the reduced model and show that the original model and our reduced model qualitatively exhibit the same properties by applying numerical techniques. Moreover, we demonstrate that the numerical results obtained in our models for camphor boats are quite similar to those in a car-following model, the OV model, but there are some different features between our reduced model and a typical OV model.

An optimal velocity estimation (OVE) model based on non-empirical formula

In many research of optimal velocity model, the optimal velocity is estimated by empirical formulas. There are several aspects of this approach that need to be improved: On the one hand, the physical significance of such empirical formulas is not clear enough. On the other hand, the empirical formula of macro results is not detailed enough at the micro level. In this paper, we derived an equation to estimate the optimal velocity from two basic assumptions. Based on this equation, the optimal velocity estimation (OVE) model was established. To verify the rationality of OVE model, we conducted two single-file pedestrian experiments. From the results of experiments, we find that pedestrians pursue a consistent velocity and a comfortable distance between pedestrians in single-file movement. And the comfortable distance is proportional to the square of the steady velocity. These conclusions provide support for our assumptions. In addition, we simulated the experiments with the OVM model and a traditional OV model. By comparison, the OVM model can reproduce macro results very well. Further, the OVM model has a better performance than traditional OV model in micro level. In view of the clear physical meanings, our OVM model has an important significance in studying the influencing factors of pedestrian movement.

Car-following Model Considering Multiple Distances and Numerical Simulation of Mixed Traffic Flow

A new car-following model with consideration of multiple distances (MDOV) was proposed based on the OV model, and the linear stability was analyzed theoretically, showing the MDOV model is more stable than OV model and the stability may enhance if considering more distances. Numerical simulation was demonstrated to study the evolution between high-velocity steady state and low-velocity steady state under different cart proportions in the mixed traffic flow. The results indicate that the steady state evolution is usually influenced by the cart number and the distances considered in MDOV model, the traffic wave spreads faster and the steady state evolution is shortened in the mixed flow than the single flow. In addition, the congestion is inhibited in the mixed flow and the effect is more obvious as the mixture ratio increases.

A new car-following model considering lateral separation and overtaking expectation

In order to depict the real car-following behaviors better, in this paper we present a new car-following model by introducing the effect parameter of lateral separation distance and proposing the concepts of overtaking expectation and virtual front car based on OV model. The stability condition of the model is obtained by using the linear stability theory. It is found that with the increase of lateral separation and overtaking expectation, the stability region of traffic flow increases at a low density while it decreases at a high density. The results of numerical simulation verify the analytic results. Thus, in some places like traffic bottlenecks, which usually have a high traffic density, it is necessary to restrict the lateral movement and overtaking behavior of vehicles for suppressing the traffic jam.

Three-lane changing behaviour simulation using a modified optimal velocity model

In real urban traffic, roadways are usually multilane and are divided into fast, medium and slow lanes according to different velocity restrictions. Microscopic modelling of single lane has been studied widely using discrete cellular automata and continuous optimal velocity models. In this paper, we extend the continuous single-lane models (OV model and FVD model) to simulate the lane-changing behaviour on an urban roadway that consists of three lanes. Considering headway difference, velocity difference, safety distance, and the probability of lane-changing intention, a comprehensive lane-changing rule set is constructed. We analyse the fundamental diagram and reveal the “faster-is-slower” effect in urban traffic induced by lane-changing behaviour. We also investigate the effect of lane-changing behaviour on the distribution of vehicles, velocity, flow and headway. Asymmetrical phenomenon with symmetrical rules on urban roadway and density inversion on the slow lane were also found. The simulation results indicate that lane-changing behaviour is not advisable on crowded urban roadway. It is hoped that information from this study may be useful for traffic control and individual moving strategy on urban roadway.

Comparison between the optimal velocity model and the Nagel-Schreckenberg model

The similarities as well as the differences of the optimal velocity model（OV model） and the Nagel-Schreckenberg model （NS model） are compared by both analytical and numerical approaches. By analyzing the rules of both models, we prove that the NS model is a discrete form model of OV model. By numerical simulations, OV model with different parameters and stochastic NS model are compared from two aspects, namely the fundamental diagram and their dynamics under open boundary conditions. The results show that these two models have very similar behaviors. However, they are different in essence, and each model has their own advantages, which makes it useful. This study provides a basis for the application and improvement of traffic flow models.

Energy Dissipation Burst on the Traffic Congestion

We introduce an energy dissipation model for traffic flow based on the optimal velocity model (OV model). In this model, vehicles are defined as moving under the rule of the OV model, and energy dissipation rate is defined as the product of the velocity of a vehicle and resistant force which works to it.