Optimal Decisions of a Supply Chain with Two Risk-Averse and Competing Retailers under Random Demand

This paper investigates the optimal decisions in a decentralized supply chain consisting of one manufacturer and two competing retailers who face price-sensitive and stochastic demand. The retailers are risk averse with conditional value at risk (CVaR) as their risk measure, and the manufacturer is a risk-neutral agent. We construct manufacturer-Stackelberg games with retailers, who engage in horizontal price competition. For the multiplicative demand model and expected demand as an exponential function of both prices, we show that there exists the optimal pricing-ordering joint decision uniquely. We then explore the influence of the price sensitivity, risk aversion, and retail competition on optimal decisions and channel efficiency. The results show that retail competition contributes to manufacturer and improves channel efficiency of the decentralized supply chain. When the retailers are more risk averse, the channel efficiency becomes much lower. However, the level of retailers’ risk aversion has no significant impact on the manufacturer’s optimal wholesale price and retailer’s optimal selling price

Analytical treatment for the development of electromagnetic cascades in intense magnetic fields

In a strong magnetic field, a high-energy photon can be absorbed and then produce an electron-positron pair. The produced electron/positron will in turn radiate a high-energy photon via synchrotron radiation, which then initiates a cascade. We built a one-dimensional Monte-Carlo code to study the development of the cascade especially after it reaches the saturated status, when almost all the energy of the primary particles transfers to the photons. The photon spectrum in this status has a cut-off due to the absorption by magnetic fields, which is much sharper than the exponential one. Below the cut-off, the spectral energy distribution (SED) manifest itself as a broken power-law with a spectral index of $0.5$ and $0.125$, respectively, below and above the broken energy. The SED can be fitted by a simple analytical function, which is solely determined by the product of the cascade scale $R$ and the magnetic field perpendicular to the motion of the particle B_{\perp}, with an accuracy better than 96\%. The similarity of the spectrum to that from the cascade in an isotropic black-body photon field is also studied.Comment: 7 pages, 7 figures, minor changes. Version to appear in PR

Modelling, dynamic analysis and control of capsubot systems with stable propulsion for medical and recovery assistances

The growth of medical robots since the mid-1980s has been striking. From a few initial efforts in stereotactic brain surgery, orthopaedics, endoscopic surgery, microsurgery, and other areas, the field has expanded to include commercially marketed, clinically deployed systems, and a robust and exponentially expanding research community. Obscure gastrointestinal (GI) bleeding, Crohn disease, Celiac disease, small bower tumors, and other disorders that occur in the GI tract have always been challenging to be diagnosed and treated due to the inevitable difficulty in accessing such a complex environment within the human body. Robot-assisted minimally invasive surgery has become an choice

On periodically pendulum-diven systems for underactuated locomotion: a viscoelastic jointed model

This paper investigates the locomotion principles and nonlinear dynamics of the periodically pendulum-driven (PD) systems using the case of a 2-DOF viscoelastic jointed model. As a mechanical system with underactuation degree one, the proposed system has strongly coupled nonlinearities and can be utilized as a potential benchmark for studying complicated PD systems. By mathematical modeling and non-dimensionalization of the physical system, an insight is obtained to the global system dynamics. The proposed 2-DOF viscoelastic jointed model establishes a commendable interconnection between the system dynamics and the periodically actuated force. Subsequently, the periodic locomotion principles of the actuated subsystem are elaborately studied and synthesized with the characteristic of viscoelastic element. Then the analysis of qualitative changes is conducted respectively under the varying excitation amplitude and frequency. Simulation results validate the efficiency and performance of the proposed system comparing with the conventional system

Modelling and control of an elastically joint-actuated cart-pole underactuated system

This paper investigates the modelling and closedloop tracking control issues of a novel elastic underactuated multibody system. A torsional inverted pendulum cart-pole system with a single rotary actuator at the pivot of the cart is proposed. The system dynamics which incorporates with motion planning is firstly described. An optimization procedure is then discussed to plan the feasible trajectories that not just meet the performance requirements but also obtain optimality with respect to the cart displacement and average velocity. A closed-loop tracking controller is designed under collocated partial feedback linearization (CPFL). Subsequent presentation of simulation demonstrates that the proposed system is promising as compared to the previous work. The paper concludes with the application of our novel scheme to the design and control of autonomous robot systems

Geometric techniques for trajectory planning and chaos control of a bio-inspired autogenetic capsule robot

Biological systems achieve energy efficient and adaptive behaviours through extensive internal and external compliance interactions. Active dynamic compliance are created and enhanced from musculoskeletal system (joint-space) to external environment (task-space) amongst the underactuated motions. The terminology bio-inspiration implies the understanding of fundamental principles underlying the motion behaviours of animals and humans and transfers these principles into the development of robotic systems. For example, during walking, the muscles constantly change their stiffness and damping when the leg is swinging forward and the foot is put on the ground. This idea enables the exploration in robotic systems with flexible elements—viscoelasticity to mimic the compliant motion of biological muscles. Underactuated systems with viscoelastic actuation are similar to these biological systems, in that their self-organisation and overall tasks must be achieved by coordinating the subsystems and dynamically interacting with the environment