Robust comprehension of natural language instructions by a domestic service robot

We present a method through which domestic service robots can comprehend natural language instructions. For each action type, a variety of natural language expressions can be used, for example, the instruction, ‘Go to the kitchen’ can also be expressed as ‘Move to the kitchen.’ We are of the view that natural language instructions are intuitive and, therefore, constitute one of the most user-friendly robot instruction methods. In this paper, we propose a method that enables robots to comprehend instructions spoken by a human user in his/her natural language. The proposed method combines action-type classification, which is based on a support vector machine, and slot extraction, which is based on conditional random fields, both of which are required in order for a robot to execute an action. Further, by considering the co-occurrence relationship between the action type and the slots along with the speech recognition score, the proposed method can avoid degradation of the robot’s comprehension accuracy in noisy environments, where inaccurate speech recognition can be problematic. We conducted experiments using a Japanese instruction data-set collected using a questionnaire-based survey. Experimental results show that the robot’s comprehension accuracy is higher in a noisy environment using our method than when using a baseline method with only a 1-best speech recognition result.     

Randomized time warping for motion recognition

Dynamic time warping (DTW) has been widely used for the alignment and comparison of two sequential patterns. In DTW, dynamic programming is used to avoid an exhaustive search for the alignment. In this paper, we propose a randomized extension of the DTW concept, termed randomized time warping (RTW), for motion recognition. RTW generates time elastic (TE) features by randomly sampling the sequential data while retaining the temporal information. A set of TE features is represented by a low-dimensional subspace, called the sequence hypothesis (Hypo) subspace, and the similarity between two sequential patterns is defined by the canonical angles between the two corresponding Hypo subspaces. In essence, RTW simultaneously computes multiple degrees of similarities between a number of warped patterns' pair candidates, while in practice, RTW generalizes the Hankel matrix commonly used in modeling of system dynamics. We demonstrate the applicability of RTW through experiments on gesture recognition using three public datasets, namely, the Cambridge gesture database, a subset of the one-shot-learning dataset from the ChaLearn Gesture Challenge, and the KTH action dataset.     

Hybrid CO2 laser waterjet heat (LWH) treatment of bindered boron nitride composites with hardness improvement

Boron nitride (BN) material is chemically and thermally stable which makes it desirable for high speed machining in demanding chemical and thermal environments. Although the hardness of BN material is well below that of single polycrystalline diamond (PCD), a laser waterjet heat (LWH) treatment process provides a new potential approach to achieve hardness values that are comparable to diamond hardness. This study investigates the hardness change of LWH-treated bindered cBN/TiN and cBN/AlN composites. Results indicate that measured hardness increase is dependent on the laser beam pass and the distance from the beam center.     

Online multi-step prediction for wind speeds and solar irradiation: Evaluation of prediction errors

We propose a general method for predicting multiple steps ahead of our target system and estimating simultaneously the prediction errors in a real time. The requirement of the proposed method is that we have a time series of the target system. We demonstrate the method by artificial data, real wind speed data, and real solar irradiation data.     

Dummy humanoid robot simulating several trunk postures and abdominal shapes – Report of element technologies

Development of clothing in consideration of the shape and body function of a person with spinal cord injury is an important task. Then, a dummy robot with a deformation mechanism was developed in this study for evaluating the comfortable level of clothings. Specifically, a trunk joint mechanism and an abdominal mechanism that can realize various deformations of the abdominal area and various trunk poses were developed. The trunk joint mechanism was implemented in order to simulate the seated posture of persons with spinal cord injury. The abdominal deformation mechanism was implemented using linear actuators and rotating servomotors in order to simulate abdominal obesity of persons with spinal cord injury. Further, a tactile sensor system was developed for measuring the clothing pressure on the abdominal area and evaluating the comfort or discomfort of clothing.     

A comparative theoretical study of CO oxidation reaction by O2 molecule over Al- or Si-decorated graphene oxide

Using density functional theory calculations, the probable CO oxidation reaction mechanisms are investigated over Al- or Si-decorated graphene oxide (GO). The equilibrium geometry and electronic structure of these metal decorated-GOs along with the O₂/CO adsorption configurations are studied in detail. The relatively large adsorption energies reveal that both Al and Si atoms can disperse on GO quite stably without clustering problem. Hence, both Al- and Si-decorated GOs are stable enough to be utilized in catalytic oxidation of CO by molecular O₂. The two possible reaction pathways proposed for the oxidation of CO with O₂ molecule are as follows: O₂ + CO → CO₂ + O_ads and CO + O_ads → CO₂. The estimated energy barriers of the first oxidation reaction on Si-decorated GOs, following the Eley–Rideal (ER) reaction, are lower than that on Al-decorated ones. This is most likely due to the larger atomic charge on the Si atom than the Al one, which tends to stabilize the corresponding transition state structure. The results of this study can be useful for better understanding the chemical properties of Al- and Si-decorated GOs, and are valuable for the development of an automobile catalytic converter in order to remove the toxic CO molecule.     

Preparation and employment of carbon nanodots to improve electron extraction capacity of polyethylenimine interfacial layer for polymer solar cells

The performance of polymer solar cells is substantially enhanced by introducing carbon nanodots as additives in polyethylenimine buffer layer. The most pronounced effect is observed in one type of device with the average power conversion efficiencies increased from 5.78% to 7.56% after the addition of carbon nanodots at an optimal concentration in the interfacial layer, which is mainly attributed to the enhanced light trapping and electron transfer in the devices. Besides the light-harvesting and electron transport capacity improvement, the addition of carbon nanodots can also increase exciton generation and dissociation, leading to a high electron mobility. This study demonstrates a facile approach for enhancing the efficiencies of polymer solar cells.     

Towards the improvement of thermal efficiency in lignite‐fired power generation: Concerning the utilization of Polish lignite deposits in state‐of‐the‐art IGCC technology

Integrated coal Gasification Combined Cycle (IGCC) is the most advanced technology for coal‐fired power generation. The two‐stage entrained flow gasification process allows for the use of a wide range of coal, as long as the gasification temperature is above the ash melting point of a used fuel. In this gasification technology, lignite, which often has a low ash melting point, can be preferably utilized. However, ash fluidity is also another importance, because the behaviour of molten slag can diminish a stable ash discharge from a gasifier. As the eligibility of coal ash properties is a considerable factor, water physically and chemically kept in lignite (30 – 60% in mass) attributes to deteriorating gasification efficiency, because it causes significant heat loss and increasing oxygen consumption. Developing a thermal evaporative lignite drying method will be a necessary attempt to apply lignite to the coal gasification process. For those preceded objectives, coal and ash properties and drying characteristics of several grades of Polish lignite, extracted from Belchatow and Turow deposits, have been experimentally investigated in a preliminary study evaluating the applicability and consideration for its utilization in state‐of‐the‐art clean coal technology, IGCC. This paper particularly discusses the eligibility of Polish lignite from the perspective of the fusibility and fluidity of ash melts and the fundamental drying kinetics of lignite in superheated steam in the light of water removal. The viscosity of ash melts is measured at high temperature up to 1700 °C. In the drying tests, the significant influence of structural issues, because of the provenance and origin of lignite on the drying characteristics, was found by applying the method of sensitivity analysis of physical propensity. This paper concludes that the investigated Polish lignite has characteristics favourable for utilization in IGCC technology, once the precautions related to its high moisture have been carefully addressed. Copyright © 2016 John Wiley & Sons, Ltd.