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Associating Semantic Sensor Web with Domain Ontology : The Way to Obtain Meaningful Sensor Data
Chaoqun Ji,Jin Liu,Xiaofeng Wang 보안공학연구지원센터 2014 International Journal of u- and e- Service, Scienc Vol.7 No.5
To realize the sharing and reuse of sensor data and improve interoperability, semantic sensor web(SSW)is proposed to add semantics information to existing sensor networksby utilizing domain, spatial and temporal anthologies and other related semantic technology.However these is seldom research on how to fully utilize the sensor data through a semantic way such as domain ontology based inference. This paperpresents stateofthe art of SSWin various aspects,and proposesthe method to associate data from semantic sensor web with domain ontology to realize the communication between different domain ontologies and SSW. In addition, this paperalso proposes a new calculation method of semantic similarity amongdifferent entities in different ontology. Experiments show that this method can effectively find the similar entitiesandrealize the knowledge sharing and ontologies reuse.
LES investigation into the generation of momentum deficits in the supersonic wake of a micro-ramp
Xiao Wang,Yonghua Yan,Zhengzhong Sun,Chaoqun Liu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4
Implicitly implemented large eddy simulation (LES) with a fifth-order WENO scheme was conducted in this study. Based on Navier- Stokes equations, this LES was carried out to explore the origin of momentum deficit caused by a supersonic micro-ramp at flow conditions of Ma = 2.5 and Reθ = 5760. The numerical results were validated through qualitative and quantitative comparisons with existing experimental data. After describing the aerodynamic properties of the supersonic wake, such as the deficit and the streamwise vortices, the momentum deficit was later detected to originate from the lower portion of the upstream boundary layer, while the high momentum fluid originated from close to the wall at the upper portion. Position alternation trigged by the micro-ramp was finally proposed as a revised mechanism.
Thermodynamic analysis of a novel adiabatic compressed air energy storage system with water cycle
Zhen Xu,Haiyang Yang,Yingchun Xie,Jinchi Zhu,Chaoqun Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6
A novel water cycle compressed air energy storage system (WC-CAES) is proposed to improve the energy storage density (ESD) and round trip efficiency (RTE) of A-CAES. The new system decreases electricity consumption by recovering and reusing the hydraulic pressure of water. The thermodynamic characteristics of WC-CAES are evaluated by energy and advanced exergy analysis method. When the air storage pressure of WC-CAES is equal to the minimum storage pressure of A-CAES (4.2 MPa), the ESD and generalized storage density increase by 5.85 % and 32.41 %, respectively. When the air storage pressure increases to the same level as A-CAES (7.2 MPa), ESD and generalized storage density increase by 112 % and 162 %, respectively. In addition, the RTE increases by 1.6 % when the air storage pressure is 4.2 MPa. WC-CAES is therefore verified to be an effective way to improve the performance of conventional A-CAES.
Fan Yang,Haicheng Yang,Yonghua Yan,Xueyan Guo,Ren Dai,Chaoqun Liu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6
Natural convection heat transfer in an inclined polar cavity was studied using a Finite-difference lattice Boltzmann method (FDLBM)based on a double-population approach for body-fitted coordinates. A D2G9 model coupled with the simplest TD2Q4 lattice model wasapplied to determine the velocity field and temperature field. For both velocity and temperature fields, the discrete spatial derivativeswere obtained by combining the upwind scheme with the central scheme, and the discrete temporal term is obtained using a fourth-orderRunge-Kutta scheme. Studies were carried out for different Rayleigh numbers and different inclination angles. The results in terms ofstreamlines, isotherms, and Nusselt numbers explain the heat transfer mechanism of natural convection in an inclined polar cavity due tothe change of Rayleigh number and inclination angle.