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Robust Stability of Nonlinear Plants with a Non-symmetric Prandtl-Ishlinskii Hysteresis Model

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International Journal of Automation and computing 2010年第2期7卷 213-218页

作者： Akira Inoue graduate school of Natural science and technology Okayama University

In this paper, robust stability of nonlinear plants represented by non-symmetric Prandtl-Ishlinskii （PI） hysteresis model is studied. In general, PI hysteresis model is the weighted superposition of play or stop hysteresis operators, and the slopes of the operators are considered to be the same. In order to make a hysteresis model, a modified form of non-symmetric play hysteresis operator with unknown slopes is given. The hysteresis model is described by a generalized Lipschitz operator term and a bounded parasitic term. Since the generalized Lipschitz operator is unknown, a new condition using robust right coprime factorization is proposed to guarantee robust stability of the controlled plant with the hysteresis nonlinearity. As a result, based on the proposed robust condition, a stabilized plant is obtained. A numerical example is presented to validate the effectiveness of the proposed method.

关键词： Prandtl-Ishlinskii (PI) hysteresis model robust stability right coprime factorization non-symmetric play hysteresis operator nonlinear plants.

Feature-aware regularization for sparse online learning

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science China(Information sciences) 2014年第5期57卷 65-85页

作者： OIWA Hidekazu MATSUSHIMA Shin NAKAGAWA Hiroshi graduate school of Information science and technology The University of Tokyo Information technology Center The University of Tokyo

Learning a compact predictive model in an online setting has recently gained a great deal of *** combination of online learning with sparsity-inducing regularization enables faster learning with a smaller memory space than the previous learning *** optimization methods and learning algorithms have been developed on the basis of online learning with L1-regularization.L1-regularization tends to truncate some types of parameters,such as those that rarely occur or have a small range of values,unless they are emphasized in ***,the inclusion of a pre-processing step would make it very difficult to preserve the advantages of online *** propose a new regularization framework for sparse online *** focus on regularization terms,and we enhance the state-of-the-art regularization approach by integrating information on all previous subgradients of the loss function into a regularization *** resulting algorithms enable online learning to adjust the intensity of each feature’s truncations without pre-processing and eventually eliminate the bias of *** show theoretical properties of our framework,the computational complexity and upper bound of *** demonstrated that our algorithms outperformed previous methods in many classification tasks.

关键词： online learning supervised learning sparsity-inducing regularization feature selection sentiment analysis

Accurate measurement and influence on device reliability of defect density of a light-emitting diode

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Chinese Physics B 2013年第10期22卷 412-416页

作者：郭祖强钱可元 Key Laboratory of Information science and technology Graduate School of Tsinghua University at Shenzhen

A method of accurately measuring the defect density of a high-power light-emitting diode （LED） is proposed. The method is based on measuring the number of emitting photons in the magnitude of 105 under the injection current as weak as nA and calculating the non-radiative recombination coefficient which is related to defect density. Defect density is obtained with the self-developed measurement system, and it is demonstrated that defect density has an important influence on LED optical properties like luminous flux and internal quantum efficiency （IQE）. At the same time, a batch of GaN-based LEDs with the chip size of 1 minx 1 mm are selected to conduct the accelerated aging tests lasting for 1000 hours. The results show that defect density exhibits a greater variation and is more sensitive to LED reliability than luminous flux during aging tests. Based on these results, it is concluded that for the GaN-based LED with a chip size of 1 mm ~ I mm, if its defect density is over 1017/cm3, the LED device performance suffers a serious deterioration, and finally fails.

关键词： accurate measurement defect density LED reliability

Potentials of GHG reductions from wastewater treatment for the CDM

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science China(Technological sciences) 2011年第7期54卷 1649-1654页

作者： Takaaki FURUBAYASHI Toshihiko NAKATA Department of Management science & technology Graduate school of Engineering Tohoku University

The study aims to evaluate the potential of GHG （greenhouse gas） reductions by installing an anaerobic digester in a wastewater treatment facility in Southeast Asia. Then the break-even point of additional investment to reduce GHG is obtained by exchanging carbon price as emissions credits. In the project scenario, the wastewater treatment system has the digester, where methane （biogas） is produced and recovered. Compared with the baseline scenario, the biogas has calorific value to produce heat and electricity, and can substitute fossil fuels for power generation. The objective of the study is to define the relationship between CERs （certified emission reductions） and investment costs, and the beak-even point, finding out the dominant pa- rameters in the system. Financial parameters such as capital costs and operating costs are considered to evaluate the investmerit costs. The result shows that the methane recovery reduces 54% of GHG emissions. Although the substitution of the biogas for the fossil fuels reduces only 6% of the GHG emissions, the electricity output can satisfy the electricity consumption. The results also show that the maximum CER credit is 73000 t-COEe/a, and the GHG reduction cost is 14 USD/t-CO2e.

关键词： wastewater treatment system anaerobic digestion GHG reductions developing countries CDM

High-quality micro-shape fabrication of monocrystalline diamond by nanosecond pulsed laser and acid cleaning

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International Journal of Extreme Manufacturing 2022年第2期4卷 173-183页

作者： Yasuhiro Okamoto Tubasa Okubo Atsuya Kajitani Akira Okada graduate school of Natural science and technology Okayama UniversityOkayamaJapan

The flat plane of small surface roughness below 0.1μm average roughness was obtained for monocrystalline diamond by nanosecond pulsed laser irradiation of 1060 nm and post-process acid cleaning,at a laser fluence around the material removal threshold *** glossy and flat plane at the bottom of the micro-groove was parallel to the top surface of the specimen,although the round beam of Gaussian mode was irradiated in the direction perpendicular to the top surface of *** square beam of top-hat mode produced a shallower micro-groove with a wider,flatter bottom compared with the round beam in Gaussian *** creation method of the flat plane with small surface roughness was discussed in the arrangement strategy of linear micro-grooving by the square beam of top-hat *** side-by-side repetition of linear micro-grooving did not create a flat plane with constant ***,a two-step scanning method was proposed in order to overcome the problem in the normal side-by-side repetition of liner ***-removal areas were partly retained between the processing lines in the first step,and the laser scanning was conducted on the retained area in the second *** newly proposed two-step scanning method was practical and useful to create a widely flat plane with small surface roughness,and the two-step scanning method provided superior control over the micro-groove *** proposed method can reduce the surface roughness in addition to the shape creation of monocrystalline diamond,and it can be used as a high-quality micro-shape fabrication method of monocrystalline diamond.

关键词： monocrystalline diamond nanosecond pulsed laser flat surface smooth surface micro-grooving

Influence of agricultural activities,forest fires and agro-industries on air quality in Thailand

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Journal of Environmental sciences 2017年第2期29卷 85-97页

作者： Worradorn Phairuang Mitsuhiko Hata Masami Furuuchi graduate school of Natural science and technology Kanazawa UniversityKanazawa 920-1192Japan

Annual and monthly-based emission inventories in northern, central and north-eastern provinces in Thailand, where agriculture and related agro-industries are very intensive,were estimated to evaluate the contribution of agricultural activity, including crop residue burning, forest fires and related agro-industries on air quality monitored in corresponding provinces. The monthly-based emission inventories of air pollutants, or, particulate matter（PM）, NOx and SO2, for various agricultural crops were estimated based on information on the level of production of typical crops： rice, corn, sugarcane, cassava, soybeans and potatoes using emission factors and other parameters related to country-specific values taking into account crop type and the local residue burning period. The estimated monthly emission inventory was compared with air monitoring data obtained at monitoring stations operated by the Pollution Control Department, Thailand（PCD） for validating the estimated emission inventory. The agro-industry that has the greatest impact on the regions being evaluated, is the sugar processing industry, which uses sugarcane as a raw material and its residue as fuel for the boiler. The backward trajectory analysis of the air mass arriving at the PCD station was calculated to confirm this influence. For the provinces being evaluated which are located in the upper northern, lower northern and northeast in Thailand, agricultural activities and forest fires were shown to be closely correlated to the ambient PM concentration while their contribution to the production of gaseous pollutants is much less.

关键词： Biomass burning Agricultural residue Agro-industry Emission inventory Air pollutants

k-Dimensional hashing scheme for hard disk integrity verification in computer forensics

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Journal of Zhejiang university-science C(Computers and Electronics) 2011年第10期12卷 809-818页

作者： Zoe Lin JIANG Lucas Chi Kwong HUI Siu Ming YIU Kam Pui CHOW school of Computer science and technology Harbin Institute of Technology Shenzhen Graduate School Department of Computer science The University of Hong Kong

Verifying the integrity of a hard disk is an important concern in computer forensics,as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation.A typical approach is to compute a single chained hash value of all sectors in a specific ***,this technique loses the integrity of all other sectors even if only one of the sectors becomes a bad sector occasionally or is modified *** this paper we propose a k-dimensional hashing scheme,kD for short,to distribute sectors into a kD space,and to calculate multiple hash values for sectors in k dimensions as integrity *** the integrity of the sectors can be verified depending on any hash value calculated using the sectors,the probability to verify the integrity of unchanged sectors can be high even with bad/modified sectors in the hard *** show how to efficiently implement this kD hashing scheme such that the storage of hash values can be reduced while increasing the chance of an unaffected sector to be verified *** results of a 3D scheme show that both the time for computing the hash values and the storage for the hash values are reasonable.

关键词： Computer forensics Digital evidence Hard disk integrity k-Dimensional hashing

Improved encoding structure and decoding algorithms for spinal codes

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Journal of Systems Engineering and Electronics 2022年第4期33卷 856-866页

作者： HUANG Wensha WANG Lina school of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Shunde graduate school University of Science and Technology BeijingBeijing 100083China

To improve the error correction performance, an innovative encoding structure with tail-biting for spinal codes is designed. Furthermore, an adaptive forward stack decoding(A-FSD) algorithm with lower complexity for spinal codes is proposed. In the A-FSD algorithm, a flexible threshold parameter is set by a variable channel state to narrow the scale of nodes accessed. On this basis, a new decoding method of AFSD with early termination(AFSD-ET) is further proposed. The AFSD-ET decoder not only has the ability of dynamically modifying the number of stored nodes, but also adopts the early termination criterion to curtail complexity. The complexity and related parameters are verified through a series of simulations. The simulation results show that the proposed spinal codes with tail-biting and the AFSD-ET decoding algorithms can reduce the complexity and improve the decoding rate without sacrificing correct decoding performance.

关键词： spinal code tail-biting encoding lower decoding complexity early termination strategy

An Ensemble Approach for Emotion Cause Detection with Event Extraction and Multi-Kernel SVMs

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Tsinghua science and technology 2017年第6期22卷 646-659页

作者： Ruifeng Xu Jiannan Hu Qin Lu Dongyin Wu Lin Gui school of Computer science and technology Harbin Institute of Technology Shenzhen Graduate School Department of Computing the Hong Kong Polytechnic University

In this paper, we present a new challenging task for emotion analysis, namely emotion cause *** this task, we focus on the detection of emotion cause a.k.a the reason or the stimulant of an emotion, rather than the regular emotion classification or emotion component extraction. Since there is no open dataset for this task available, we first designed and annotated an emotion cause dataset which follows the scheme of W3 C Emotion Markup Language. We then present an emotion cause detection method by using event extraction framework,where a tree structure-based representation method is used to represent the events. Since the distribution of events is imbalanced in the training data, we propose an under-sampling-based bagging algorithm to solve this problem. Even with a limited training set, the proposed approach may still extract sufficient features for analysis by a bagging of multi-kernel based SVMs method. Evaluations show that our approach achieves an F-measure 7.04%higher than the state-of-the-art methods.

关键词： emotion cause detection event extraction multi-kernel SVMs bagging