Mapping parameter spaces of biological switches

Since the seminal 1961 paper of Monod and Jacob, mathematical models of biomolecular circuits have guided our understanding of cell regulation. Model-based exploration of the functional capabilities of any given circuit requires systematic mapping of multidimensional spaces of model parameters. Despite significant advances in computational dynamical systems approaches, this analysis remains a nontrivial task. Here, we use a nonlinear system of ordinary differential equations to model oocyte selection in Drosophila, a robust symmetry-breaking event that relies on autoregulatory localization of oocyte-specification factors. By applying an algorithmic approach that implements symbolic computation and topological methods, we enumerate all phase portraits of stable steady states in the limit when nonlinear regulatory interactions become discrete switches. Leveraging this initial exact partitioning and further using numerical exploration, we locate parameter regions that are dense in purely asymmetric steady states when the nonlinearities are not infinitely sharp, enabling systematic identification of parameter regions that correspond to robust oocyte selection. This framework can be generalized to map the full parameter spaces in a broad class of models involving biological switches.

Catastrophe Pre-Warning of Multi-Modular Floating Platforms with Ordinal Partition Networks

Use of artificial networks to signify the onset of dynamic catastrophes in engineering systems is a simple and efficient strategy. Here an ordinal partition network and its construction from time series are introduced. The selection of mapping parameter is discussed in detail, which may significantly enhance the performance of the proposed method. Topological properties of the resulting network can sensitively detect the dynamic changes of original underlying systems, making the strategy workable. A Catastrophe Prediction Index (CPI) is proposed to serve as a monitoring indicator for pre-warning catastrophe events. The numerical results verify the feasibility of the proposed method.

Learning-Based Adaptive Management of QoS and Energy for Mobile Robotic Missions

Mobile robotic systems are normally confronted with the shortage of on-board resources such as computing capabilities and energy, as well as significantly influenced by the dynamics of surrounding environmental conditions. This context requires adaptive decisions at run-time that react to the dynamic and uncertain operational circumstances for guaranteeing the performance requirements while respecting the other constraints. In this paper, we propose a reinforcement learning (RL)-based approach for Quality of Service QoS and energy-aware autonomous robotic mission manager. The mobile robotic mission manager leverages the idea of (RL) by monitoring actively the state of performance and energy consumption of the mission and then selecting the best mapping parameter configuration by evaluating an accumulative reward feedback balancing between QoS and energy. As a case study, we apply this methodology to an autonomous navigation mission. Our simulation results demonstrate the efficiency of the proposed management framework and provide a promising solution for the real mobile robotic systems.

Theoretical Analysis and Circuit Verification for Fractional-Order Chaotic Behavior in a New Hyperchaotic System

A novel nonlinear four-dimensional hyperchaotic system and its fractional-order form are presented. Some dynamical behaviors of this system are further investigated, including Poincaré mapping, parameter phase portraits, equilibrium points, bifurcations, and calculated Lyapunov exponents. A simple fourth-channel block circuit diagram is designed for generating strange attractors of this dynamical system. Specifically, a novel network module fractance is introduced to achieve fractional-order circuit diagram for hardware implementation of the fractional attractors of this nonlinear hyperchaotic system with order as low as 0.9. Observation results have been observed by using oscilloscope which demonstrate that the fractional-order nonlinear hyperchaotic attractors exist indeed in this new system.

Kicking Motion Imitation of Inverted-Pendulum Mobile Robot and Development of Body Mapping from Human Demonstrator

This paper proposes a new method for learning the dynamic motion of an inverted-pendulum mobile robot from the observation of a human player’s demonstration. First, an inverted-pendulum mobile robot with upper and lower body links observes the human demonstration with a camera and extracts the human region in images. Second, the robot maps the region to its own two links and estimates link posture trajectories. The robot starts learning kicking based on the trajectory parameters for imitation. Through this process, our robot can learn dynamic kicking shown by a human. The mapping parameter gives an important role for successive imitation. A reasonable and feasible procedure of learning from observation for an inverted-pendulum robot is proposed. Learning performance from observation is investigated, then, the development of body mapping is proposed and investigated.

EXPERIMENTAL VERIFICATION OF A FOUR-DIMENSIONAL CHUA'S SYSTEM AND ITS FRACTIONAL ORDER CHAOTIC ATTRACTORS

This paper introduces a modified Chua's system which is a smooth four-dimensional continuous-time autonomous chaotic system with a cubic nonlinearity. Some dynamical behaviors of this 4-D Chua's system are further investigated by means of Poincaré mapping, parameter phase portraits, equilibrium points, bifurcations and calculated Lyapunov exponents. Moreover, using RC-opamp and analog multiplier we describe a simple electronic circuit for hardware implementation of the 4-D Chua's system which differ from previously reported Chua's circuits. Various attractors of experimental results from this chaotic oscillator are in good agreement with theoretical analysis. In particular, based on the approximation theory of fractional-order operator, a relevant analog circuit diagram of this fractional-order modified Chua's system is designed with α = 0.9. Observation results demonstrate that chaos exists indeed in this fractional-order modified Chua's system with an order as low as 3.6. This fractional-order oscillation circuit, for the first time in the literature, realizes high-dimensional Chua's chaotic system.

Re-assembling formal features in second language acquisition: beyond minimalism

In this commentary, Lardiere's discussion of features is compared with the use of features in constraint-based theories, and it is argued that constraint-based theories might offer a more elegant account of second language acquisition (SLA). Further evidence is reported to question the accuracy of Chierchia's (1998) Nominal Mapping Parameter.

Some thoughts on the contrastive analysis of features in second language acquisition

In this article I discuss the selection and assembly of formal features in second language acquisition. Assembling the particular lexical items of a second language (L2) requires that the learner reconfigure features from the way these are represented in the first language (L1) into new formal configurations on possibly quite different types of lexical items in the L2. I illustrate the nature of the problem by comparing the assembly and expression of features involved in plural-marking in English, Mandarin Chinese and Korean, and situate this comparison with respect to specific claims of the Nominal Mapping Parameter and within a discussion of parameter (re)setting more generally. I conclude with a few even more general thoughts on the role of Universal Grammar (UG) in (second) language acquisition.

Resetting the Nominal Mapping Parameter in L2 English: Definite article use and the count–mass distinction

This paper presents two experiments in the acquisition of the nominal domain in English by Japanese and Spanish second language (L2) learners. The first experiment tests the L2 learners' ability to distinguish between count and mass nouns using a grammaticality judgement task and the second experiment tests learners on different types of definite (based on J. Hawkins's 1978 taxonomy) in count and mass contexts by means of a forced-choice elicitation task. The claim by Chierchia (1998a, b) is that there is a Nominal Mapping Parameter and the three languages discussed in this paper each have a different parametric value. The aim of the paper is to test Japanese and Spanish L2 learners of English to see whether they can reset the parameter to the English setting.