基于经济和稳定的电力系统最优运行策略

电力系统中带暂态稳定约束的最优潮流(OTS)问题是一个甚至在小规模电力系统中都难以精确处理的泛函数空间非线性优化问题,文中避开直接处理这一复杂问题,将带暂态稳定约束的潮流优化问题等价转换为欧几里德空间的优化问题,然后采用最优潮流(OPF)中常用的标准非线性规划法来解决此问题。经过转换后的OTS,在形式上和OPF有相同的变量,这样即使对于一个存在众多暂态稳定约束和多个扰动的大型电力系统,也变得容易求解。所提出的方法可以适用于任何发电机系统、控制器或者输电网络模型,不仅可以直接用于计算系统最优运行点,还可以应用于电力市场内电价的精确估价以及预防性稳定控制、电压下降问题和可用传输容量计算等领域。     

A brush device with visual and haptic feedback for virtual painting of 3D virtual objects

We have previously developed a mixed reality (MR) painting system with which a user could take a physical object in the real world and apply virtual paint to it. However, this system could not provide the sensation of painting on virtual objects in MR space. Therefore, we subsequently proposed and developed mechanisms that simulated the effect of touch and movement when a brush device was used to paint on a virtual canvas. In this paper, we use visual and haptic feedback to provide the sensation of painting on virtual three-dimensional objects using a new brush device called the MAI Painting Brush++. We evaluate and confirm its effectiveness through several user studies.     

Social intelligence design in online chat communication: a psychological study on the effects of “congestion”

Social intelligence design (SID) is an essential concept for constructing electronic communities or computer-supported communication systems which effectively support various intelligent activities. This study is focused on one example of such systems, that is, online chat for real-time computer-mediated communication. We examined various dimensions of human information processing in online chat sessions from both the cognitive and social perspectives within psychology. A key variable which affects the process of a chat session is what we call communication congestion. We regard this quality as characterizing online chat sessions and are experimentally exploring its effects on chat performance and cognition processing by participants. Results of this experimental study suggest that medium-density congestion with a relevant topic might activate communication, particularly for experienced participants. Based on our findings, we discuss some suggestions regarding future innovations for chat systems.

An integration of bottom-up and top-down salient cues on RGB-D data: saliency from objectness versus non-objectness

Bottom-up and top-down visual cues are two types of information that helps the visual saliency models. These salient cues can be from spatial distributions of the features (space-based saliency) or contextual/task-dependent features (object-based saliency). Saliency models generally incorporate salient cues either in bottom-up or top-down norm separately. In this work, we combine bottom-up and top-down cues from both space- and object-based salient features on RGB-D data. In addition, we also investigated the ability of various pre-trained convolutional neural networks for extracting top-down saliency on color images based on the object dependent feature activation. We demonstrate that combining salient features from color and dept through bottom-up and top-down methods gives significant improvement on the salient object detection with space-based and object-based salient cues. RGB-D saliency integration framework yields promising results compared with the several state-of-the-art-models.     

Hydrated metal salt and Y3Fe5O12–Na0.5K0.5NbO3-incorporated P(VDF-HFP) films: a promising combination of materials with multiferroic and energy harvesting properties

Journal of Materials Science - The composite approach is very effective in developing multiferroic systems with remarkable magnetoelectric coupling coefficients. In this work, P(VDF-HFP)-based...     

Constructing vision-driven indicators to enhance the interaction between science and society

Scientometrics - In this fast-paced modern world, science, technology, and innovation (STI) are key drivers that impact all areas of life at individual and organisational levels, deepening the...     

Synthesis of degradable network polymers containing peroxy units in the main chain or the cross-linking point

We have synthesized degradable network polymers containing readily labile peroxy bonds as the repeating units in the main chain or as the cross-linking point in the side chain. Poly(2-hydroxyethyl sorbate-alt-O₂) was obtained by the radical copolymerization of 2-hydroxyethyl sorbate with oxygen, and then cross-linked using tolylene 2,4-diisocyanate as the cross-linking agent to obtain a new type of degradable gel. We also investigated the cross-linking of conventional polymers by the reaction of the diene moieties introduced into the polymer side chain with oxygen. The hydroxy group in the side chain of poly(vinyl alcohol) (PVA) was reacted with 1-isocyanate-1,3-pentadiene in order to introduce a diene moiety into the side chain of the PVA. The dienylated PVA was reacted with oxygen in the presence of a radical initiator, leading to the formation of a gel containing a labile peroxy linkage at the cross-linking point. These gels containing peroxy units in the main chain or at the cross-linking points degraded upon heating.     

Effect of Partition Wall on Heat Transfer Characteristics of a Gas-to-Gas Counterflow Microchannel Heat Exchanger

The effect of a partition wall on heat transfer characteristics of a two-stream gas-to-gas counterflow microchannel heat exchanger has been numerically investigated. The flow passages of the microchannel heat exchanger are plane channels of 100 μm in height and 20 mm in length. The material of the partition wall is assumed to be stainless steel. The computations were performed for a wide range of flow rate to investigate heat transfer characteristics of the microchannel heat exchanger. Moreover, computations for various partition wall thicknesses were conducted to investigate the effect of the wall thickness. The thickness ranged from 200 μm to 6 μm while the channel height was fixed at 100 μm. Numerical results show that heat transfer characteristics of a gas-to-gas counterflow microchannel heat exchanger are affected by partition wall thickness. Computations for various partition wall thicknesses and thermal conductivities of the partition wall were performed. The results were compared with those of a single microchannel with constant wall temperature. Applicability of the assumption of constant wall temperature was revealed.     

Experimental investigations of laminar,transitional and turbulent Gas flow in microchannels

This paper presents experimental results on flow characteristics of laminar, transitional and turbulent gas flows through microchannels. The experiments were performed for three microchannels etched into silicon wafers, capped with glass with hydraulic diameters of 69.48, 99.36 and 147.76 μm. The stagnation pressure was designated in such a way that the flow is laminar, transitional and turbulent with the outflow at atmosphere condition. The pressure was locally measured at seven locations along the channel length to determine local values of Mach number and friction factor from laminar to turbulent flow. The result shows f ? Re is a function of Mach number and is higher than incompressible value due to the compressibility effect for laminar flow. The Darcy friction factor with flow acceleration loss is higher than the Fanning friction factor for both laminar and turbulent flow. The friction factors were also compared with empirical correlations in the literature and Moody’s chart.     

Dynamic force reduction and heat transfer improvement for horizontal tubes in large-particle gas-fluidized beds

The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces are smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces.