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Joint Relay-and-Antenna Selection and Power Allocation for AF MIMO Two-way Relay Networks
( Wang Xiaoxiang ),( Zhou Jia ),( Wang Dongyu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.3
In this paper, we present a joint relay-and-antenna selection and power allocation strategy for multiple-input multi-output (MIMO) amplify-and-forward (AF) two-way relay networks (TWRNs). In our approach, we select the best transmit and receive antennas at the two sources, a best relay and a best transmit and receive antenna at the selected relay based on maximizing the minimum of the end-to-end received signal-to-noise-ratios (SNRs) under a total transmit power constraints. We obtained the closed-form solution for the optimal power allocation firstly. Then with the optimal allocation solution we found, we can reduce the joint relay-and-antenna selection to a simpler problem. Besides, the overall outage probability is investigated and a tight closed-form approximation is derived, which provides a method to evaluate the outage performance easily and fast. Simulation results are presented to verify the analysis.
A Simulation Study on the Impact of Abandoned Trolley Cases on Pedestrian Evacuation
Dongyue Xu,Jinghong Wang,Juan Liu,Yan Wang,Juncheng Jiang 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3
Many pedestrians empirically think that discarding luggage can improve evacuation efficiency, but it is unclear whether discarding luggage is an effective evacuation strategy. Previous models also oversimplified the interference of abandoned luggage on pedestrians. Hence, an extended social force model integrates pedestrian interaction with abandoned luggage like trolley cases was firstly proposed. A simulation based on a real metro station was carried out to examine the effectiveness of evacuation strategy like abandoning trolley cases at the bottleneck such as gate machine and metro carriage door, and the influence mechanism of abandoned trolley cases on pedestrians was investigated. The results show that discarding the trolley cases at the gate machine and at the metro carriage door cannot improve evacuation efficiency but increase the evacuation time by 78.7% and 14.9% at these two positions when the carrying ratio is 50%, respectively. When the occupancy rate of trolley case at the gate machine and metro carriage door is below 19% and 11%, pedestrians tend to detour the abandoned trolley cases and this behavior significantly increased the collisions between pedestrians at bottlenecks, and when the occupancy rate exceeds, they tend to push aside the trolley cases and the evacuation efficiency is further reduced.
Facile Fabrication of Hollow Li3PO4 Catalyst via Ostwald Ripening
Jihai Zhang,Dongyu Wang,Weihua Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.1
Hollow inorganic nanostructures are important due to their applications in energy storage and conversion, catalysis, gas sensing, and biomedicine. Li3PO4 is used as an isomerization catalyst for propylene oxide to selectively give allyl alcohol. We used a facile template-free method to synthesize hollow Li3PO4 nanoparticles with size range of 500 nm to 1500 nm. The effect of concentration, agitation, ripening temperature and the ratio of starting reagents on the hollowing process is investigated. The most important factor to influence the hollowness was found to be the ratio of lithium ion to phosphate ion; as the ratio increases, the hollowness of the particles increases. When this ratio reached 3, the hollow nanostructures become dominant. As an isomerization catalyst for propylene oxide, 4-Li3PO4 exhibited the highest conversion and best selectivity of allyl alcohol. The hydroxide ion of the precursor is adsorbed on the surface of the Li3PO4 particles which results in different surface basicity.
Sustainable Development of Indonesia`s Agricultural Sector
( Eng Seng Chia ),( Dongyu Li ),( Xutong Ma ),( Jixi Wang ),( Yiting Wang ),( Jiaxu Zhu ) 한국시스템다이내믹스학회 2016 한국시스템다이내믹스 연구 Vol.17 No.4
The Indonesian agricultural output has been struggling to provide for the demand of the rising population in recent years owing to the sluggish growth rate in this sector as compared to the overall performance of the economy. While the current slash-and-burn technique widely employed by Indonesian peasants is able to boost the output in the short term, its negative implications on the environment and the constraints in available forest area casts doubts to its sustainability in the long run. As the results from our iThink model simulation has illustrated, the output will cease increasing and decline in about 90 years” time due to the drastic drop in forest coverage. Based on the sensitivity analysis of the affecting factors, three policy amendments are proposed to avert the gloomy perspective, namely increasing funding for Research and Development, curbing burning activities, and actively returning abandoned land to forests. With the effective implementation of the suggested policies, the growth in the agricultural sector will be steered back to a sustainable track, which is further confirmed by the model projection.
Probabilistic-based damage identification based on error functions with an autofocusing feature
Gorgin, Rahim,Ma, Yunlong,Wu, Zhanjun,Gao, Dongyue,Wang, Yishou Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.4
This study presents probabilistic-based damage identification technique for highlighting damage in metallic structures. This technique utilizes distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. Diagnostic signals were used to define the scatter signals of different paths. The energy of scatter signals till different times were calculated by taking root mean square of the scatter signals. For each pair of parallel paths an error function based on the energy of scatter signals is introduced. The resultant error function then is used to estimate the probability of the presence of damage in the monitoring area. The presented method with an autofocusing feature is applied to aluminum plates for method verification. The results identified using both simulation and experimental Lamb wave signals at different central frequencies agreed well with the actual situations, demonstrating the potential of the presented algorithm for identification of damage in metallic structures. An obvious merit of the presented technique is that in addition to damages located inside the region between transducers; those who are outside this region can also be monitored without any interpretation of signals. This novelty qualifies this method for online structural health monitoring.
Baiquan Liu,Honglong Ning,Lei Wang,Jianhua Zou,Zhongwei Zhou,Miao Xu,Hong Tao,Dongyu Gao,Linfeng Lan,Junbiao Peng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-
An efficient single-emitting layer hybrid white organic light-emitting diode (WOLED) was developed,simultaneously fulfilling low efficiency roll-off, stable color and extreme luminance. At the practicalluminance of 1000 cd/m2, a total current efficiency of 42.8 cd/A and power efficiency of 19.2 lm/W areachieved, maintaining as high as 40.5 cd/A and 15.5 lm/W even at 5000 cd/m2. Besides, a slight colorvariation [(0.025, 0.011)] and extreme luminance ( 106 cd/m2) are obtained. The working mechanism isunveiled and it is demonstrated that the triplet-exciton-confining ability of electron transport layersplays a more vital role in device performances, particularly for the lifetime.
Probabilistic-based damage identification based on error functions with an autofocusing feature
Rahim Gorgin,Yunlong Ma,Zhanjun Wu,Dongyue Gao,Yishou Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.4
This study presents probabilistic-based damage identification technique for highlightingdamage in metallic structures. This technique utilizes distributed piezoelectric transducers to generate andmonitor the ultrasonic Lamb wave with narrowband frequency. Diagnostic signals were used to define thescatter signals of different paths. The energy of scatter signals till different times were calculated by takingroot mean square of the scatter signals. For each pair of parallel paths an error function based on the energyof scatter signals is introduced. The resultant error function then is used to estimate the probability of thepresence of damage in the monitoring area. The presented method with an autofocusing feature is applied toaluminum plates for method verification. The results identified using both simulation and experimentalLamb wave signals at different central frequencies agreed well with the actual situations, demonstrating thepotential of the presented algorithm for identification of damage in metallic structures. An obvious merit ofthe presented technique is that in addition to damages located inside the region between transducers; thosewho are outside this region can also be monitored without any interpretation of signals. This noveltyqualifies this method for online structural health monitoring.
High-performance hybrid white organic light-emitting diodes employing p-type interlayers
Baiquan Liu,Hong Tao,Jianhua Zou,Miao Xu,Dongyu Gao,Linfeng Lan,Lei Wang,Honglong Ning,Junbiao Peng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-
A simplified hybrid white organic light-emitting diode (WOLED) employing a p-type interlayer isdesigned, simultaneously realizing high efficiency, high color rendering index (CRI), low efficiency roll-off, low voltage and stable color. The device exhibits maximum total efficiencies of 29.8 cd/A and20.9 lm/W, which slightly decrease to 28.6 cd/A and 16.5 lm/W even at a high luminance of 5000 cd/m2. Besides, a slight color-shift and a CRI of 85 at 100 cd/m2 (3.65 V) are obtained. Such superior resultssystematically demonstrate that the use of p-type interlayer is a new way to realize high-performancehybrid WOLEDs.