A control law for vehicle merging inspired by dragonfly behavior

Autonomous control of vehicles has recently attracted considerable attention. In this sense, vehicle merging has become an important topic in this field of research. However, in conventional studies, the controlled vehicle must calculate the movement of other surrounding vehicles to complete the merge, requiring high computational costs. In this paper, we focus on dragonfly behavior to solve this issue. Indeed, insects can behave adaptively in the complex real world in spite of the limited size of their brains. They reduce the computational requirements of their brain by relying on different properties of their surroundings, basing their intelligent behaviors on simple strategies. The behavior of a dragonfly when chasing a prey is an example of these strategies. In this study, we address the vehicle merging maneuver by applying dragonfly’s strategies to control the movement of the merging vehicle. We propose a simple control method inspired by the aforementioned strategies and, finally, we present simulation results that were conducted to demonstrate the effectiveness of this method.     

Nickel‐Catalyzed Suzuki–Miyaura Coupling of a Tertiary Iodocyclopropane with Wide Boronic Acid Substrate Scope: Coupling Reaction Outcome Depends on Radical Species Stability

We describe a nickel‐catalyzed Suzuki–Miyaura arylation of a tertiary iodocyclopropane with arylboronic acids; this is an efficient and convergent strategy for providing various enantioenriched arylcyclopropanes with a quaternary stereogenic center. This is the first metal‐catalyzed coupling between a tertiary alkyl electrophile and a wide range of aromatics, including heteroaromatics. We found that the outcome of the Ni‐catalyzed coupling with halides as electrophiles was dependent on the stability of the radical species formed during the reaction. The use of tert‐butyl alcohol (t‐BuOH) as the reaction solvent was very effective, because of its stability under the radical‐generating reaction conditions.

     

Spray-dry synthesis of β-Cu1.8Zn0.2V2O7 ceramic fine particles showing giant negative thermal expansion

We used spray-dry method to synthesize fine powder of β-Cu_1.8Zn_0.2V₂O₇ showing large negative thermal expansion (NTE) linearly to temperature over a wide temperature range. The NTE of β-Cu_1.8Zn_0.2V₂O₇ is produced by microstructures consisting of voids and anisotropic thermal deformation of crystal grains in ceramics. By reducing the size of the microstructures that produce NTE, large NTE equivalent to that of bulk was realized, even for ceramic particles of about 2 μm size. Comparison with particles produced using a conventional method demonstrates that the particle size distribution is narrow and that the particles are nearly spherical. This achievement is expected to pave the way to use of NTE materials in micrometer-scale control of thermal expansion.     

Development of localization system using ultrasonic sensor for an underwater robot to survey narrow environment

This paper describes a localization system for a swimming robot to survey underwater narrow environments. In that environment, external sensors cannot be set up to localize the robot position, as there are many structures and the robot moves three-dimensionally. Therefore, the position needs to be calculated only by internal sensors. In this work, a new localization method based on map-matching is proposed, referring to cross-sectional shape data cut from a three-dimensional computer-aided design (CAD) data as an environmental map and structural shapes measured by a range sensor. As a range sensor, an ultrasonic sensor which is two-dimensional scanning-type was developed. The reflected signals of the ultrasonic sensor have some noise. Only structural shape data are extracted from the reflected signals. The image correlation is used as the matching method. Experiments to evaluate the performance of the proposed system were implemented at a mock-up environment. As a result, it was confirmed that the position was detected with an accuracy of 100 mm. The error is mainly caused by measurement error of the ultrasonic sensor that is used to calculate structural shapes. We concluded to improve the measurement accuracy of the ultrasonic sensor to reduce localization error.     

Asymmetry in object substitution masking occurs relative to the direction of spatial attention shift.

A sparse mask that persists beyond the duration of a target can reduce its visibility, a phenomenon called object substitution masking. Y. Jiang and M. M. Chun (2001a) found an asymmetric pattern of substitution masking such that a mask on the peripheral side of the target caused stronger substitution masking than on the central side. Assuming spatial attention was focused toward the target, the peripheral and central masks were located in the same and opposite direction of an attentional path with reference to the target in their study. We hypothesized that this asymmetric mask configuration relative to the attentional shift contributes to asymmetric substitution masking. To test this hypothesis, we conducted four experiments among which the presence or absence of the center–periphery relationship and the presence or absence of the asymmetric mask configuration were manipulated independently and orthogonally. The results suggest that asymmetric substitution masking occurs relative to the direction of spatial attention irrespective of the central–peripheral relation. We propose that the asymmetry in substitution masking might be explained by attentional momentum associated with orienting toward the target. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of different moderator ratios with light and heavy water cooled reactors in equilibrium states

As an issue of sustainable development in the world, energy sustainability using nuclear energy may be possible using several different ways such as increasing breeding capability of the reactors and optimizing the fuel utilization using spent fuel after reprocessing as well as exploring additional nuclear resources from sea water. In this present study the characteristics of light and heavy water cooled reactors for different moderator ratios in equilibrium states have been investigated. The moderator to fuel ratio (MFR) is varied from 0.1 to 4.0. Four fuel cycle schemes are evaluated in order to investigate the effect of heavy metal (HM) recycling. A calculation method for determining the required uranium enrichment for criticality of the systems has been developed by coupling the equilibrium fuel cycle burn-up calculation and cell calculation of SRAC 2000 code using nuclear data library from the JENDL 3.2. The results show a thermal spectrum peak appears for light water coolant and no thermal peak for heavy water coolant along the MFR (0.1 ? MFR ? 4.0). The plutonium quality can be reduced effectively by increasing the MFR and number of recycled HM. Considering the effect of increasing number of recycled HM; it is also effective to reduce the uranium utilization and to increase the conversion ratio. trans-Plutonium production such as americium (Am) and curium (Cm) productions are smaller for heavy water coolant than light water coolant. The light water coolant shows the feasibility of breeding when HM is recycled with reducing the MFR. Wider feasible area of breeding has been obtained when light water coolant is replaced by heavy water coolant.     

Multiple fuzzy state-value functions for human evaluation through interactive trajectory planning of a partner robot

The purpose of this study is to develop partner robots that can obtain and accumulate human-friendly behaviors. To achieve this purpose, the entire architecture of the robot is designed, based on a concept of structured learning which emphasizes the importance of interactive learning of several modules through interaction with its environment. This paper deals with a trajectory planning method for generating hand-to-hand behaviors of a partner robot by using multiple fuzzy state-value functions, a self-organizing map, and an interactive genetic algorithm. A trajectory for the behavior is generated by an interactive genetic algorithm using human evaluation. In order to reduce human load, human evaluation is estimated by using the fuzzy state-value function. Furthermore, to cope with various situations, a self-organizing map is used for clustering a given task dependent on a human hand position. And then, a fuzzy state-value function is assigned to each output unit of the self-organizing map. The robot can easily obtain and accumulate human-friendly trajectories using a fuzzy state-value function and a knowledge database corresponding to the unit selected in the self-organizing map. Finally, multiple fuzzy state-value functions can estimate a human evaluation model for the hand-to-hand behaviors. Several experimental results show the effectiveness of the proposed method.     

STORY GENERATION BASED ON DYNAMICS OF THE MIND

A story generation system based on dynamics of the mind is presented. Semantic theories until now avoided discussing a linkage of language with encyclopedic human knowledge. This paper attacks the problem of how to make clear the complicated, wide-ranging dynamics of the mind and how to connect it to language.
First, the background of this study is shown, in which our model of the mind, with both five levels along the concept formation process and eight domains according to the contents of mental activities, is surveyed.
Based on this model, then, the dynamics of mind are discussed, along an Aesop fable. A unit of data processing in the mind is called a "module," and the mental dynamics are considered as a chain activation of those modules, represented by a dynamic network. Next, a method for story generation is discussed. Propositional information of a sentence is embedded in a slot of activated, frame-structured modules, and the discourse structure of a generated story basically depends on the dynamic network. Both the chain activation and the generation processes are verified by experiments.
Lastly, residual problems of our research, a comparison with related research, and its applications are discussed.
This case study would be expected to give a basis to integrated systems for problem solving, natural language and image understandings, their generations, and intelligent robots.     

Memory encoding by theta phase precession in the hippocampal network

Recent experimental evidence on spike-timing-dependent plasticity and on phase precession (i.e., the theta rhythm dependent firing of rat hippocampal cells) associates the contribution of phase precession to episodic memory. This article aims at clarifying the role of phase precession in memory storage. Computer simulations show that the memory storage in the behavioral timescale varies in timescale of the temporal sequence from half a second to several seconds. In contrast, the memory storage caused by traditional rate coding is restricted to the temporal sequence within 40 ms. During phase precession, memory storage of a single trial experience is possible, even in the presence of noise. It is therefore concluded that encoding by phase precession is appropriate for memory storage of the temporal sequence in the behavioral timescale.