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| 1 | A novel strong tracking finite-difference extended Kalman filter for nonlinear eye tracking显示文摘Non-intrusive methods for eye tracking are important for many applications of vision-based human computer interaction. However,due to the high nonlinearity of eye motion,how to ensure the robust-ness of external interference and accuracy of eye tracking poses the primary obstacle to the integration of eye movements into today's interfaces. In this paper,we present a strong tracking finite-difference extended Kalman filter algorithm,aiming to overcome the difficulty in modeling nonlinear eye tracking. In filtering calculation,strong tracking factor is introduced to modify a priori covariance matrix and improve the accuracy of the filter. The filter uses finite-difference method to calculate partial derivatives of nonlinear functions for eye tracking. The latest experimental results show the validity of our method for eye tracking under realistic conditions. | ZHANG ZuTao ZHANG JiaShu | 2009 | Science in China(Series F)2009，52，4： | 11 |
| 2 | A strong tracking nonlinear robust filter for eye tracking显示文摘Non-intrusive methods for eye tracking are important for many applications of vision-based human computer interaction.However,due to the high nonlinearity of eye motion,how to ensure the robustness of external interference and accuracy of eye tracking pose the primary obstacle to the integration of eye movements into today's interfaces.In this paper,we present a strong tracking unscented Kalman filter (ST-UKF) algorithm,aiming to overcome the difficulty in nonlinear eye tracking.In the proposed ST-UKF,the Suboptimal fading factor of strong tracking filtering is introduced to improve robustness and accuracy of eye tracking.Compared with the related Kalman filter for eye tracking,the proposed ST-UKF has potential advantages in robustness and tracking accuracy.The last experimental results show the validity of our method for eye tracking under realistic conditions. | Zutao ZHANG Jiashu ZHANG | 2010 | 控制理论与应用(英文版)2010，8，4： | 9 |
| 3 | A new real-time eye tracking based on nonlinear unscented Kalman filter for monitoring driver fatigue显示文摘A new scheme for driver fatigue detection is presented, which is based on the nonlinear unscented Kalman filter and eye tracking. Assuming a probability distribution than to approximate an arbitrary nonlinear function or transformation, eye nonlinear tracking can be achieved using an unscented transformation (UT), which adopts a set of deterministic sigma points to match the posterior probability density function of the eye movement. Driver fatigue can be detected using the percentage of eye closure (PERCLOS) framework in a realistic driving condition after the eye nonlinear tracking. This system was tested adequately in realistic driving environments with subjects of different genders, with/without glasses, in day/night driving, being commercial/noncommercial drivers, in continuous driving time, and under different road conditions. The last experimental results show that the proposed method not only improves the robustness for nonlinear eye tracking, but also can provide more accurate estimation than the traditional Kalman filter. | Zutao ZHANG 1 , 2 , Jiashu ZHANG 2 (1.School of Mechanical Engineering, Southwest Jiaotong University, Chengdu Sichuan 610031, China 2.Sichuan Key Lab of Signal and Information Processing, Southwest Jiaotong University, Chengdu Sichuan 610031, China) | 2010 | 控制理论与应用(英文版)2010，8，2： | 5 |
| 4 | A high-efficiency regenerative shock absorber considering twin ball screws transmissions for application in range-extended electric vehicles显示文摘Renewable energy technologies,particularly in electric vehicles(EVs),have received significant attention in re-cent years.The wasted energy in a vehicle’s shock absorber can be converted into an alternative energy source by regenerative shock absorbers.In this paper,a high-efficiency regenerative shock absorber considering twin ball screws transmissions is proposed for application in range-extended electric vehicles.The proposed regenerative shock absorber can convert vibrational kinetic energy,which is traditionally dissipated as heat in suspension systems,into electricity.The proposed system is divided into four modules:suspension vibration input module,transmission module,generator module and power storage module.Induced by road roughness,the irregular linear oscillations of the suspension are transmitted to the suspension vibration input module.The reciprocating vibrations are converted into unidirectional rotation of the generator by a pair of ball screws,gears,and two overrun clutches in the transmission module.The utilisation of different screw pitches leads to different damping coefficients for upward and downward progress,enabling the shock absorber to fully utilise elastic elements to im-prove vehicle comfort when compressed and quickly absorb vibrations when stretched.The electricity produced by the generator is stored in supercapacitors to charge the battery and extend the range of EVs.The mechanical properties of the full-scaled fabricated prototype were studied by utilising a mechanical testing and sensing fix-ture.An average power output of 3.701 W in 1Hz-3 mm sinusoidal vibration input and a peak efficiency of 51.1%and average efficiency of 36.4%were achieved in a bench tests.The range can be approximately extended by 1 mile per 100 miles when EV is driving on the road of class B with a speed of 60 km/h,demonstrating that the proposed high-efficiency regenerative shock absorber is beneficial for harvesting renewable energy,and practical and significant for extending the range of EVs. | Zhanwen Wang Tianming Zhang Zutao Zhang Yanping Yuan Yujie Liu | 2020 | Energy and Built Environment2020，1，1： | 1 |
| 5 | Spatiotemporal variations of CO_(2) fluxes in a Cynodon-dominated riparian zone of the Three Gorges Reservoir(TGR),China显示文摘Aims Riparian ecosystems play an important role in overall ecosystem function,including the global carbon cycle of terrestrial ecosystems,at both landscape and global scales.Yet few studies have reported in situ measurements of CO_(2) in riparian areas where flooding is a unique disturbance to carbon cycling.Methods At multiple locations across riparian zones(RZ)with different water submergences in Xiangxi Bay(XXB),we studied seasonal variations of CO_(2) exchange between this Cynodon-dominated community and the atmosphere for 2 years by using static chambers.Important Findings We found that the seasonal changes in CO_(2) fluxes were apparent and dependent on the biophysical environment.In the beginning of spring,low gross primary productivity(GPP)in lightly flooded zones(LFZ)resulted in a positive net ecosystem exchange(NEE),indicating a net CO_(2) source.With the increase in temperature,more species and vegetation abundance appeared,and the increased GPP turned the LFZ from a net CO_(2) source into a sink.This transi-tion seemed predominantly controlled by the physiological growth of vegetation.The mean NEEs,REs and the light-use efficiency(α)of the vegetation at HFZ and MFZ were significantly higher than those at LFZ and UFZ.Yet the coefficients of variation(CV)of NEE and RE at MFZ and HFZ were lower than those at LFZ and UFZ.Submergence promoted the emission and uptake of CO_(2) to the atmosphere.Elongated submergence reduced the number of spe-cies and lowered the spatial variability of the RZ,further lowering the variation of the CO_(2) exchange. | Wenli Zhang Jiquan Chen Ju Liu Fangqing Chen Quanfa Zhang Zutao Ouyang Changliang Shao Yi Fan Wennian Xu | 2018 | Journal of Plant Ecology2018，11，6： | 1 |
| 6 | Inferring decelerated land subsidence and groundwater storage dynamics in Tianjin–Langfang using Sentinel-1 InSAR显示文摘To meet the growing demand for socioeconomic development,a large amount of groundwater is extracted from confined aquifers worldwide.The North China Plain has experienced considerable groundwater depletion and subsidence during the past six decades.In this study,we use Sentinel-1A/B SAR images from 2015 to 2020 to map the ground subsidence of the Tianjin–Langfang area.Three subsiding zones centered at Guangyang,Wuqing–Bazhou,and Jinghai are identified with maximum subsidence rates of 98.1,121.8,and 104.7 mm/yr.Seasonal and long-term signals are separated from time series subsidence and hydraulic measurements using continuous wavelet transform to retrieve aquifer parameters.The long-term subsidence,which fits well with an exponential decaying model,remarkably slows down in our study area.The elastic skeletal storage coefficients range between 0.52×10−3 and 9.66×10−3.We then retrieve the spatial–temporal variations of total groundwater storage,recoverable groundwater storage,and irreversible groundwater storage.Groundwater storage depletion rates are apparently reducing,which benefits from the operation of the South-to-North Water Transfer Project and local groundwater management practices. | Xuguo Shi Tongtong Zhu Wei Tang Mi Jiang Houjun Jiang Chen Yang Wei Zhan Zutao Ming Shaocheng Zhang | 2022 | International Journal of Digital Earth2022，15，1： | 0 |
| 7 | Potential for energy conservation:A portable desktop paper reusing system for office waste paper显示文摘Renewable paper reusing plays a significant role in the sustainable environment under the background of the shortage in forest resources and the pollution from the paper industry.The conventional reusing stream of waste office paper appears to have low reusing rates while consuming massive amounts of energy in intermediate steps.In this study,we developed a novel portable renewable desktop paper reusing system based on font area detection and greyscale sensor.The proposed system consists of two main parts,namely,a greyscale sensor and font area detection model and a polishing mechanism.Acting as an ink mark detector for waste desktop paper,the greyscale sensor and font area detection model can detect the font in the waste desktop paper using an adaptive dynamic compensation schematic.The polishing mechanism will grind the font area of the wasted desktop paper,and this paper reusing processing is non-chemical,energy saving and environmentally friendly.The proposed system is demonstrated through simulations and experimental results,which show that the proposed renewable desktop paper reusing system is portable and is effective for reusing waste office paper in the office.An accuracy of 99.78%is demonstrated in the greyscale sensor and font area detection model,and the average reuse rate of one piece of paper is 2.52 times,verifying that the proposed portable system is effective and practical in renewable desktop paper reusing applications. | Tingsheng Zhang Xinglong Liu Yajia Pan Zutao Zhang Yanping Yuan | 2020 | Energy and Built Environment2020，1，2： | 0 |
| 8 | Elastic energy storage technology using spiral spring devices and its applications:A review显示文摘Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-friendliness.This paper elaborates the operational principles and technical properties and summarizes the appli-cability of elastic energy storage technology with spiral springs.Elastic energy storage using spiral spring can realize the balance between energy supply and demand in some applications.Continuous input-spontaneous out-put working style can provide simple energy sources for short-time energy supply,and provide strong moment impact and rapid start,or realize the energy conservation for reciprocating movement.Uniform output working style can realize energy output with uniform speed for timekeeping and load-driving.Random input working style can harvest and store random mechanical energy or convert small torque into a large moment to drive external loads.Finally,this paper proposes new researches and developments of elastic energy storage technology on new materials and structures,mechanical properties and structural dynamics analyses,design and control for new functions. | Shiwei Guo Li Yang Yanping Yuan Zutao Zhang Xiaoling Cao | 2023 | Energy and Built Environment2023，4，6： | 0 |
| 9 | A portable,auxiliary photovoltaic power system for electric vehicles based on a foldable scissors mechanism显示文摘In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.The system includes a photovoltaic power generation module and an electricity transfer module.The photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.The electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were conducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.The results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system. | Zhou Jin Dongyang Li Daning Hao Zutao Zhang Liang Guo Xiaoping Wu Yanping Yuan | 2024 | Energy and Built Environment2024，5，1： | 0 |
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