46 results on '"Ziyan Jia"'
Search Results
2. The characteristics of arterial spin labeling cerebral blood flow in patients with subjective cognitive decline: The Chinese imaging, biomarkers, and lifestyle study
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Wenyi, Li, Jiwei, Jiang, Xinying, Zou, Yuan, Zhang, Mengfan, Sun, Ziyan, Jia, Wei, Li, and Jun, Xu
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General Neuroscience - Abstract
ObjectiveWe aimed to characterize the potential risk factors and cerebral perfusion of patients with subjective cognitive decline (SCD).MethodsThis prospective study enrolled consecutive patients from the Chinese Imaging, Biomarkers, and Lifestyle (CIBL) Cohort of Alzheimer’s disease between February 2021 and March 2022. Patients who met the SCD diagnostic criteria were categorized into the SCD group, while those without cognitive complaints or any concerns were assigned to the healthy control (HC) group. The demographic and clinical characteristics and cerebral blood flow (CBF) from pseudo-continuous arterial spin labeling (pCASL) in standard cognitive regions were compared between these two groups. A multivariate analysis was performed to identify independent factors associated with SCD.ResultsThe frequency of family history of dementia in the SCD group was higher compared with the HC group (p = 0.016). The CBF of left hippocampus (p = 0.023), left parahippocampal gyrus (p = 0.004), left precuneus (p = 0.029), left middle temporal gyrus (p = 0.022), right parahippocampal gyrus (p = 0.018), and right precuneus (p = 0.024) in the SCD group were significantly increased than those in the HC group. The multivariate logistic regression analyses demonstrated that the family history of dementia [OR = 4.284 (1.096–16.747), p = 0.036] and the CBF of left parahippocampal gyrus [OR = 1.361 (1.006–1.840), p = 0.045] were independently associated with SCD.ConclusionThis study demonstrated that the family history of dementia and the higher CBF within the left parahippocampal gyrus were independent risk factors associated with patients with SCD, which could help in the early identification of the SCD and in intervening during this optimal period.
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- 2022
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3. Triplet exciton formation for non-radiative voltage loss in high-efficiency nonfullerene organic solar cells
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Yuan Zhang, Haiming Zhu, Ziyan Jia, Guanqing Zhou, Xufeng Li, Yang Yang, Yuexia Wu, Jianqiu Xu, Xuning Zhang, Weimin Liu, Xu Chen, Chunfeng Zhang, Xinhui Lu, Zeng Chen, Xinxin Xia, and Chao Deng
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Materials science ,Organic solar cell ,Exciton ,Photovoltaic system ,Energy conversion efficiency ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Acceptor ,0104 chemical sciences ,General Energy ,Chemical physics ,Ultrafast laser spectroscopy ,0210 nano-technology ,Spectroscopy ,Recombination - Abstract
Summary Nonfullerene acceptor (NFA) organic solar cells (OSCs) with power conversion efficiency (PCE) reaching up to 18% has shown tremendous potential toward practical applications. However, the non-radiative recombination loss in high-efficiency NFA OSCs is evidently large, and the origin remains unclear. Herein, by combining transient absorption spectroscopy, photovoltaic characterization, and detailed energy loss analysis, we unambiguously show the formation of NFA triplet exciton from free carrier recombination as a main non-radiative recombination and energy loss channel. More importantly, in contrast to the previous energetics point of view, we show side-chain fluorination in high-efficiency NFA OSCs has little effect on charge transfer energy landscapes but efficiently inhibits charge recombination to NFA triplet excitons, leading to higher V OC and PCE. Our findings provide a new view about energy loss in NFA OSCs and pave the way toward OSCs with lower V OC loss and efficiency exceeding 20%.
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- 2021
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4. Oxytocin treatments or activation of the paraventricular nucleus-the shell of nucleus accumbens pathway reduce adverse effects of chronic social defeat stress on emotional and social behaviors in Mandarin voles
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Wenjuan Hou, Shuying Huang, Lu Li, Xing Guo, Zhixiong He, Shufeng Shang, Ziyan Jia, Lizi Zhang, Yishan Qu, Caihong Huang, Yin Li, Yitong Li, Zijian Lv, and Fadao Tai
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Pharmacology ,Cellular and Molecular Neuroscience - Published
- 2023
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5. Potential Diagnostic Applications of Multi-Delay Arterial Spin Labeling in Early Alzheimer's Disease: The Chinese Imaging, Biomarkers, and Lifestyle Study
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Mengfan Sun, Yan-Li Wang, Runzhi Li, Jiwei Jiang, Yanling Zhang, Wenyi Li, Yuan Zhang, Ziyan Jia, Michael Chappell, and Jun Xu
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General Neuroscience ,mild cognitive impairment, arterial transit time, diagnosis, multi-delay arterial spin labeling, Alzheimer’s disease, cerebral blood flow - Abstract
BackgroundCerebral blood flow (CBF) alterations are involved in the onset and progression of Alzheimer’s disease (AD) and can be a potential biomarker. However, CBF measured by single-delay arterial spin labeling (ASL) for discrimination of mild cognitive impairment (MCI, an early stage of AD) was lack of accuracy. Multi-delay ASL can not only provide CBF quantification but also provide arterial transit time (ATT). Unfortunately, the technique was scarcely applied to the diagnosis of AD. Here, we detected the utility of ASL with 1-delay and 7-delay in ten regions of interest (ROIs) to identify MCI and AD.Materials and MethodsPseudocontinuous ASL (pCASL) MRI was acquired on a 3T GE scanner in adults from the Chinese Imaging, Biomarkers, and Lifestyle (CIBL) Study of AD cohort, including 26 normal cognition (NC), 37 MCI, and 39 AD. Receiver operating characteristic (ROC) analyses with 1-delay and 7-delay ASL were performed for the identification of MCI and AD. The DeLong test was used to compare ROC curves.ResultsFor CBF of 1-delay or 7-delay the AUCs showed moderate-high performance for the AD/NC and AD/MCI comparisons (AUC = 0.83∼0.96) (p < 0.001). CBF of 1-delay performed poorly in MCI/NC comparison (AUC = 0.69) (p < 0.001), but CBF of 7-delay fared well with an AUC of 0.79 (p < 0.001). The combination of CBF and ATT of 7-delay showed higher performance for AD/NC, AD/MCI, and MCI/NC comparisons with AUCs of 0.96, 0.89, and 0.89, respectively (p < 0.001). Furthermore, combination of CBF, ATT, sex, age, APOE ε4, and education improved further the accuracy (p < 0.001). In subgroups analyses, there were no significant differences in CBF of 7-delay ASL for identification of AD or MCI between age subgroups (p > 0.05).ConclusionThe combination of CBF and ATT with 7-delay ASL showed higher performance for identification of MCI than CBF of 1-delay, when adding to sex, age, APOE ε4 carrier status, and education years, the diagnostic performance was further increased, presenting a potential imaging biomarker in early AD.
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- 2022
6. Intelligent Reflecting Surface Aided MIMO Cognitive Radio Systems
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Tiecheng Song, Yu Wang, Zhang Lei, Cunhua Pan, Ziyan Jia, and Weige Tao
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Mathematical optimization ,Computer Networks and Communications ,business.industry ,Computer science ,Transmitter ,MIMO ,Aerospace Engineering ,020302 automobile design & engineering ,02 engineering and technology ,Spectral efficiency ,Interference (wave propagation) ,Precoding ,Cognitive radio ,0203 mechanical engineering ,Automotive Engineering ,Wireless ,Electrical and Electronic Engineering ,business - Abstract
In cognitive radio (CR) systems, the spectrum efficiency (SE) of the secondary users (SUs) is always limited by the interference temperature constraint imposed on the primary users (PUs). Intelligent reflecting surface (IRS) has been recently proposed as a revolutionary technique which can help to enhance the SE of wireless communications. In this paper, we propose to employ an IRS to assist the SUs’ data transmission in the multiple-input multiple-output (MIMO) CR system. By jointly optimizing the transmit precoding (TPC) of the SU transmitter (ST) and the phase shifts of the IRS, we aim to maximize the achievable weighted sum rate (WSR) of SUs subject to the ST's total power, the PU's interference temperature and unit modulus constraints. To solve this complicated optimization problem in which the variables are coupled, the block coordinate descent (BCD) algorithm is introduced to alternately solve the subproblems. For each subproblem, the Lagrange dual or inner approximation method is adopted with a low complexity. Simulation results confirm the benefits of employing IRS in a MIMO CR system. The performance comparisons of the proposed algorithm with several other benchmarks are carried out by evaluating the impacts of various parameters on the WSR.
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- 2020
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7. Efficient and Reproducible Monolithic Perovskite/Organic Tandem Solar Cells with Low-Loss Interconnecting Layers
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Xu Chen, Xuehui Xu, Jianwu Chen, Chenying Yang, Feng Tao, Zeng Chen, Tianyu Liu, Tingming Jiang, Xinya Chen, Ziyan Jia, Wei E. I. Sha, Yang Yang, Haiming Zhu, Weidong Shen, and Lizhong Bai
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Materials science ,Organic solar cell ,Tandem ,Band gap ,business.industry ,Energy conversion efficiency ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Uv sensitivity ,0104 chemical sciences ,Organic semiconductor ,General Energy ,Optoelectronics ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
Summary Perovskite solar cells (PSCs) and organic photovoltaics (OPVs) have both undergone rapid development recently. The composition and molecular tunability of perovskite and organic semiconductors enable a large material pool with different band gaps and various physical characters, giving feasibility to construct perovskite/organic tandem solar cells (TSCs). Here, we developed a semi-empirical model, rationally selected the best available material combination, and successfully demonstrated the efficient and reproducible TSCs benefiting from their complementary band gaps and orthogonal processing solvents. Featuring with all-thermally evaporated low-loss interconnecting layers (ICLs), our 2-termimal (2T) monolithic perovskite/organic TSCs deliver high reproducibility with power conversion efficiency (PCE) narrowly distributed between 20% and 20.6% (certified as 19.54%). In addition to the promising efficiency, the UV sensitivity of OPVs is eliminated in the tandem structure, demonstrating its advantage on device stability. Those results unfold significant potentials of perovskite/organic tandem devices as reproducible and cost-effective structures to achieve high-performance TSCs.
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- 2020
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8. Mediation of the APOE Associations With Cognition Through Cerebral Blood Flow: The CIBL Study
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Yan-Li Wang, Mengfan Sun, Fang-Ze Wang, Xiaohong Wang, Ziyan Jia, Yuan Zhang, Runzhi Li, Jiwei Jiang, Linlin Wang, Wenyi Li, Yongan Sun, Jinglong Chen, Cuicui Zhang, Baolin Shi, Jianjian Liu, Xiangrong Liu, and Jun Xu
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Aging ,Cognitive Neuroscience - Abstract
BackgroundThe ε4 allele of the apolipoprotein E (APOE) gene is a strong genetic risk factor for aging-related cognitive decline. However, the causal connection between ε4 alleles and cognition is not well understood. The objective of this study was to identify the roles of cerebral blood flow (CBF) in cognitive-related brain areas in mediating the associations of APOE with cognition.MethodsThe multiple linear regression analyses were conducted on 369 subjects (mean age of 68.8 years; 62.9% of women; 29.3% of APOE ε4 allele carriers). Causal mediation analyses with 5,000 bootstrapped iterations were conducted to explore the mediation effects.ResultAPOE ε4 allele was negatively associated with cognition (P < 0.05) and CBF in the amygdala, hippocampus, middle temporal gyrus, posterior cingulate, and precuneus (all P < 0.05). The effect of the APOE genotype on cognition was partly mediated by the above CBF (all P < 0.05).ConclusionCBF partially mediates the potential links between APOE genotype and cognition. Overall, the APOE ε4 allele may lead to a dysregulation of the vascular structure and function with reduced cerebral perfusion, which in turn leads to cognitive impairment.
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- 2022
9. Involvement of Ventral Tegmental Area to Anterior Cingulate Cortex Dopamine Projections in Empathetic Behavior in Male C57 Mice
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Yitong Li, Wenjuan Hou, Shufeng Shang, Lizi Zhang, Yishan Qu, Jing Liu, Zijian Lv, Ziyan Jia, Xing Guo, Lu Li, Yin Li, Caihong Huang, Rui Jia, Zhixiong He, and Fadao Tai
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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10. Association of migraine with patent foramen ovale closure: A systematic review and
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Yan-Li, Wang, Fang-Ze, Wang, Yuan, Zhang, Jiwei, Jiang, Ziyan, Jia, Xiangrong, Liu, Jian, Wang, and Jun, Xu
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The potential correlation between patent foramen ovale (PFO) and migraine has been previously reported, but whether PFO closure plays a role in reducing migraine burden has not reached an agreement.We searched PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Science Technology Periodical Database and China Biology Medicine Database (CBM) through September 30, 2021 to identify associations between PFO closure and outcome of migraine burden. The control groups consisted of drug treatment or sham procedure.Three randomized clinical trials (RCT) and 9 case-control studies were eligible for inclusion (1754 participants), of which 7 reported nonrecurrence of migraine, 4 reported reduced migraine-frequency and migraine-days, and 5 reported HIT-6 score and 4 reported MIDAS score. The mean (SD) age of participants was 40.68 (3.81) years and 1340 (76.39%) were women. PFO closure was significantly associated with a reduced risk of migraine-recurrence by 4.47 (95% CI, 2.94-6.80; ITranscatheter PFO closure is significantly associated with burden reduction of migraine headache.
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- 2021
11. Plasma p-tau181 Level Predicts Neurodegeneration and Progression to Alzheimer's Dementia: A Longitudinal Study
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Yan-Li Wang, Jinglong Chen, Zhong-Li Du, Haoyi Weng, Yuan Zhang, Runzhi Li, Ziyan Jia, Mengfan Sun, Jiwei Jiang, Fang-Ze Wang, Jun Xu, and Alzheimer's Disease Neuroimaging Initiative
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cognition ,Apolipoprotein E ,Oncology ,Longitudinal study ,medicine.medical_specialty ,NeuroImage ,cerebrospinal fluid (CSF) ,Internal medicine ,medicine ,Dementia ,plasma p-tau181 ,Cognitive decline ,RC346-429 ,Original Research ,medicine.diagnostic_test ,business.industry ,Area under the curve ,Cognition ,Neuropsychological test ,Alzheimer's disease ,medicine.disease ,Neurology ,Biomarker (medicine) ,Neurology. Diseases of the nervous system ,Neurology (clinical) ,business - Abstract
Background: Plasma-based biomarkers would be potential biomarkers for early diagnosis of Alzheimer's disease (AD) because they are more available and cost-effective than cerebrospinal fluid (CSF) or neuroimaging. Therefore, we aimed to evaluate whether phosphorylated tau181 (p-tau181) in plasma could be an accurate AD predictor.Methods: Participants from the ADNI database included 185 cognitively unimpaired subjects with negative Aβ (CU–), 66 subjects with pre-clinical AD (CU with positive Aβ), 164 subjects with mild cognitive impairment with negative Aβ (MCI–), 254 subjects with prodromal AD (MCI with positive Aβ), and 98 subjects with dementia. Multiple linear regression models, linear mixed-effects models, and local regression were used to explore cross-sectional and longitudinal associations of plasma p-tau181 with cognition, neuroimaging, or CSF biomarkers adjusted for age, sex, education, and APOE genotype. Besides, Kaplan–Meier and adjusted Cox-regression model were performed to predict the risk of progression to dementia. Receiver operating characteristic analyses were performed to evaluate the predictive value of p-tau181.Results: Plasma p-tau181 level was highest in AD dementia, followed by prodromal AD and pre-clinical AD. In pre-clinical AD, plasma p-tau181 was negatively associated with hippocampal volume (β = −0.031, p-value = 0.017). In prodromal AD, plasma p-tau181 was associated with decreased global cognition, executive function, memory, language, and visuospatial functioning (β range −0.119 to −0.273, p-value < 0.05) and correlated with hippocampal volume (β = −0.028, p-value < 0.005) and white matter hyperintensity volume (WMH) volume (β = 0.02, p-value = 0.01). In AD dementia, increased plasma p-tau181 was associated with worse memory. In the whole group, baseline plasma p-tau181 was significantly associated with longitudinal increases in multiple neuropsychological test z-scores and correlated with AD-related CSF biomarkers and hippocampal volume (p-value < 0.05). Meanwhile, CU or MCI with high plasma p-tau181 carried a higher risk of progression to dementia. The area under the curve (AUC) of the adjusted model (age, sex, education, APOE genotype, and plasma p-tau181) was 0.78; that of additionally included CSF biomarkers was 0.84.Conclusions: Plasma p-tau181 level is related to multiple AD-associated cognitive domains and AD-related CSF biomarkers at the clinical stages of AD. Moreover, plasma p-tau181 level is related to the change rates of cognitive decline and hippocampal atrophy. Thus, this study confirms the utility of plasma p-tau181 as a non-invasive biomarker for early detection and prediction of AD.
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- 2021
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12. Understanding of the Nearly Linear Tunable Open-Circuit Voltages in Ternary Organic Solar Cells Based on Two Non-fullerene Acceptors
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Zeng Chen, Ziyan Jia, Xu Chen, Haiming Zhu, Lizhong Bai, and Yang Michael Yang
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Materials science ,Fullerene ,Organic solar cell ,Open-circuit voltage ,business.industry ,Photovoltaic system ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Acceptor ,010309 optics ,0103 physical sciences ,Optoelectronics ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology ,Ternary operation ,business ,Voltage ,Perovskite (structure) - Abstract
Although the power conversion efficiencies (PCEs) of the state-of-the-art organic solar cells (OSCs) have exceeded 17%, the organic photovoltaic devices still suffer from considerable voltage losses compared with the inorganic or perovskite solar cells. Therefore, the optimization of open-circuit voltage (VOC) is of great significance for the improvement of the photovoltaic performance of OSCs. The origins of VOC have been well-established in the binary system; however, the understanding of VOC in non-fullerene acceptor (NFA)-based ternary OSCs is still lacking. Herein, we have developed a series of ternary organic photovoltaic devices, exhibiting nearly linear increased VOC as the increase of ITIC third content. We found that both the effective charge-transfer (CT) states and the nonradiative recombination losses of the bulk-heterojunction (BHJ) are altered in the ternary blends, and they collectively contribute to the tunable VOC. Our results provide a perspective for understanding the origin of VOC in NFA-based ternary OSCs.
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- 2020
13. A case study of frontal variant of Alzheimer disease
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Jiong Shi, Jun Xu, Qidong Chen, Qian Zhang, and Ziyan Jia
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Epidemiology ,business.industry ,Health Policy ,Neuropsychology ,medicine.disease ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,Developmental Neuroscience ,medicine ,Dementia ,Neurology (clinical) ,Geriatrics and Gerontology ,Cognitive decline ,Alzheimer's disease ,business ,Clinical psychology - Published
- 2020
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14. Ultrafast Hole Transfer and Carrier Transport Controlled by Nanoscale-Phase Morphology in Nonfullerene Organic Solar Cells
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Beibei Qiu, Haiming Zhu, Guanqing Zhou, Yongfang Li, Ziyan Jia, Zeng Chen, Weijian Tao, Xu Chen, and Yang Michael Yang
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Materials science ,Organic solar cell ,Photovoltaic system ,Resolution (electron density) ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chemical physics ,Phase (matter) ,Microscopy ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy ,Ultrashort pulse ,Nanoscopic scale - Abstract
Nonfullerene acceptors (NFAs) have attracted great attention in high-efficiency organic solar cells (OSCs). While the effect of molecular properties including structures and energetics on charge transfer has been extensively investigated, the effect of macroscopic-phase properties is yet to be revealed. Here we have performed a correlation study of the nanoscale-phase morphology on the photoexcited hole transfer (HT) process and photovoltaic performance by combining ultrafast spectroscopy with high temporal resolution and photo-induced force microscopy (PiFM) with high spatial and chemical resolution. In PM6/IT-4F, we observe biphasic HT behavior with a minor ultrafast (
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- 2020
15. Association of migraine with patent foramen ovale closure: A systematic review and meta-analysis
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Yan-Li Wang, Fang-Ze Wang, Yuan Zhang, Jiwei Jiang, Ziyan Jia, Xiangrong Liu, Jian Wang, and Jun Xu
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History ,Polymers and Plastics ,Business and International Management ,Cardiology and Cardiovascular Medicine ,Industrial and Manufacturing Engineering - Published
- 2022
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16. Twisted molecule-based hyper-crosslinked porous polymers for rapid and efficient removal of organic micropollutants from water
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Ziyan Jia, Chen Tian, Jiannan Pan, and Daqiang Yuan
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Pollutant ,chemistry.chemical_classification ,Bisphenol A ,Aqueous solution ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Polymer ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,chemistry.chemical_compound ,Monomer ,Adsorption ,chemistry ,Chemical engineering ,Triptycene ,0210 nano-technology ,Porosity ,0105 earth and related environmental sciences - Abstract
Organic micropollutants have become serious threats to human health and the environment over the past years. Novel materials and technologies are urgently needed to remove environmental contaminants. Herein, spirobifluorene (SBF) and triptycene (TP) were crosslinked to produce four hierarchically porous organic polymers (NHCPs). The twisted spatial structures of the monomers endow the NHCPs with high surface areas and abundant pores, which make them suitable for removal of pollutants in aqueous solution through adsorption. According to the results from adsorption experiments, the NHCPs exhibited high removal efficiency and adsorption capacities for pollutants in solution. Particularly, NHCP-3 could remove 99.4% of bisphenol A (BPA) in a few seconds with a maximum adsorption capacity of 562 mg g−1. Furthermore, the NHCPs could be easily recovered by immersion in ethanol and recycled at least five times without a loss in efficiency.
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- 2018
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17. Spin torque nano-oscillators based on isolated edge skyrmions in nano-pillars with perpendicular anisotropy
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Guihua Li, Cuixiu Zheng, Gang Lv, Fengwei Sun, Sai Zhou, Chao Zhang, Hong Zhang, Ziyan Jia, Zhiwei Hou, Feng Gao, and Yaowen Liu
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Physics ,Condensed matter physics ,Oscillation ,Skyrmion ,General Physics and Astronomy ,Radius ,Polarizer ,Edge (geometry) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Magnetic field ,law ,0103 physical sciences ,010306 general physics ,Nanopillar ,Spin-½ - Abstract
The magnetic skyrmions have received a lot of attention because they have potential applications in spin torque nano-oscillators. In this paper, we numerically and analytically study the dynamics of edge skyrmions in circular nano-pillar oscillators with perpendicular magnetic anisotropy (PMA) free layer and spin polarizer. Numerical simulations demonstrate that a steady edge skyrmion oscillation mode with GHz frequency can be driven by spin currents and magnetic fields. The oscillation frequencies in circular nano-pillars with different radius are analytically derived, which agrees well with the numerical results. In addition, the steady oscillations of edge skyrmions are also observed in elliptical nano-pillars, in which the oscillation frequencies strongly depend on the eccentricity and perimeter of the elliptical nanopillar. It is found that the oscillation frequency of this edge skyrmion can range from 1 GHz to 6.7 GHz. The line width is about 55 MHz.
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- 2021
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18. 19.34 cm2 large-area quaternary organic photovoltaic module with 12.36% certified efficiency
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Sheng Rui, Yang Yang, Yan Buyi, Xu Chen, Yao Jizhong, Haiming Zhu, Ziyan Jia, and Zeng Chen
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Physics ,Fabrication ,Organic solar cell ,Absorption spectroscopy ,business.industry ,Photovoltaic system ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,010309 optics ,0103 physical sciences ,Optoelectronics ,0210 nano-technology ,business - Abstract
In this study, a quaternary blending strategy was applied in the fabrication of organic photovoltaic devices and large-area modules. As a result, the ultimate quaternary organic solar cells (OSCs) deliver 16.71% efficiency for small-area devices and 13.25% for large-area ( 19.34 cm 2 ) modules (certified as 12.36%), which is one of the highest efficiencies for organic solar modules to date. Our results have proved the synergistic effects of multiple components in OSCs, providing an effective strategy for achieving high-performance organic photovoltaic devices and modules.
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- 2021
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19. The controllable synthesis of ultrafine one-dimensional small-molecule semiconducting nanocrystals in surfactant-assisted wet chemical reactions and their confinement effect
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Ziyan Jia, Jingjing Liu, Longtian Kang, Jiannian Yao, Jiannan Pan, and Ping Huang
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Ammonium bromide ,Nanostructure ,Photoluminescence ,Materials science ,Scanning electron microscope ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallinity ,chemistry ,Chemical engineering ,Nanocrystal ,Materials Chemistry ,Absorption (chemistry) ,0210 nano-technology ,High-resolution transmission electron microscopy - Abstract
One-dimensional (1D) small-molecule semiconducting nanostructures (NSs) have attracted more and more attention due to their unique structures and photoelectric properties. However, the preparation of real ultrafine 1D organic nanocrystals (ONCs), in which the intermolecular charge transfer (CT) is confined to a 1D direction, is still a huge challenge. Here, we report a facile way to controllably synthesize uniform 1D ONCs of μ-oxo dimeric iron(III) porphyrin [(FeTPP)2O] in a cetyltrimethyl ammonium bromide (CTAB)-assisted wet chemical reaction (WCR). In this work, the shape evolution of the (FeTPP)2O NSs was shown by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Interestingly, the regularity and aspect ratio of the (FeTPP)2O 1D NCs increased with time, while their diameters decreased. Further experiments proved that this was closely associated to the reconstruction of the CTAB micelles. After optimizing the experimental conditions, we not only synthesized uniform 1D ONCs with a width of ∼28 nm and/or an aspect ratio of ∼37, but also obtained 2D ONCs with a thickness of about 10 nm. Here, the finest 1D ONCs that we have seen to date have been prepared. The corresponding UV-vis absorption and photoluminescence (PL) spectra are enhanced with a decrease in the diameter and an increase in the aspect ratio of (FeTPP)2O 1D ONCs with high crystallinity, which clearly shows the first report of the confinement effect of the intermolecular CT state in 1D ONCs. This work paves a new route to prepare 1D ONCs and provides us with a chance to further understand and apply the intermolecular CT in 1D organic photoelectrical devices.
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- 2017
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20. An Improved Gauss-Seidel Algorithm for Signal Detection in Massive MIMO Systems
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Baolong Li, Ziyan Jia, Zhao Xiaoqing, Liu Yang, Zhou Cheng, Qiong Wu, and Zhengquan Li
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Minimum mean square error ,Computational complexity theory ,Iterative method ,Computer science ,MIMO ,Telecommunications link ,Relaxation (iterative method) ,Detection theory ,Gauss–Seidel method ,Algorithm ,Computer Science::Information Theory - Abstract
Massive multiple input multiple output (MIMO) is a promising technology that has been proposed to meet the requirement of the fifth generation wireless communications systems. For uplink massive MIMO systems, the typical linear detection such as minimum mean square error (MMSE) shows near-optimal performance. However, due to the direct matrix inverse, the computational complexity of the MMSE detection algorithm is too high, especially when there are a large number of users. Thus, in this paper, we propose an improved Gauss-Seidel algorithm by utilizing delayed over relaxation (DOR) scheme, which is named as delayed over relaxation Gauss-Seidel (DRGS) algorithm. The basic idea of the DOR scheme is to combine the predicted iterative step (n + 1) with the iteration of step (n − 1). The scheme can provide a significant improvement of the convergence speed for iterative algorithm. The theoretical analysis of DRGS algorithm shows that the proposed algorithm can reduce the computational complexity from O (K3) to O (K2), where K is the number of users. Simulation results verify that the DRGS algorithm can achieve almost the same BER performance as that of MMSE detection with a small number of iterations.
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- 2019
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21. A novel robust spatial spectrum sensing algorithm
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Lianfeng Shen, Zhengquan Li, Ming Wu, Ziyan Jia, Rui Zhang, and Tiecheng Song
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Noise power ,Computer science ,Approximation algorithm ,020206 networking & telecommunications ,020302 automobile design & engineering ,Jamming ,02 engineering and technology ,Spatial spectrum ,Cognitive radio ,0203 mechanical engineering ,Sampling (signal processing) ,Robustness (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,Algorithm design ,Performance indicator ,Algorithm - Abstract
This paper proposed a robust spatial spectrum sensing algorithm to apply to a communication scenario which exist the estimated error of noise power and the jamming. A modified approximate model is proposed to include the estimated error of noise power and the jamming. The corresponding performance indicators are proposed. The proposed robust algorithm estimates the estimated error vector of noise power and the jamming vector, independently. The estimated error vector of noise power and the jamming vector are separated from model coefficient vector, and the influence of estimated error and jamming is mitigated. The robustness of proposed algorithm is achieved. Simulation results show that the proposed robust algorithm has best sensing performances, and best accuracy of PU estimation, comparing with other sparsity algorithms. The sensing performances of proposed robust algorithm are not easy to be affected by the sampling rate of secondary users. When the sampling rate of secondary users or SNR is increasing, these sensing performances of proposed robust algorithm are also increasing.
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- 2017
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22. Indoor Localization System for Mobile Target Tracking Based on Visible Light Communication
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Yueyue Zhang, Guo Zhiming, Lianfeng Shen, Ziyan Jia, and Weiwei Xia
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Positioning system ,business.industry ,Computer science ,Visible light communication ,020206 networking & telecommunications ,02 engineering and technology ,Kalman filter ,Tracking (particle physics) ,0202 electrical engineering, electronic engineering, information engineering ,Wireless ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,business ,Trilateration - Abstract
In this paper, a positioning system is designed based on the visible light communication (VLC) technology for the tracking of mobile target in the indoor environment. The practical received signal strength (RSS) can be measured for subsequent positioning algorithm by using the designed system. Based on the practical measurements, an empirical equation is proposed to estimate the target's distances relative to the referenced LEDs. Then, taking advantage of the relative distances, the location estimation can be obtained by the trilateration method. Furthermore, Kalman Filter is used for improving the positioning result computed by trilateration method. Finally, experimental results show that the average location errors by adopting the derived empirical formula and trilateration can reach to 3.4cm, and the accuracy of positioning can be promoted to 2.6cm by using Kalman Filter in a real wireless environment.
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- 2017
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23. A VLC-Based 3-D Indoor Positioning System Using Fingerprinting and K-Nearest Neighbor
- Author
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Ziyan Jia, Yaping Zhu, Ming Xu, Lianfeng Shen, and Weiwei Xia
- Subjects
020210 optoelectronics & photonics ,Positioning system ,Indoor positioning system ,Time-division multiplexing ,Computer science ,0202 electrical engineering, electronic engineering, information engineering ,Sampling (statistics) ,Visible light communication ,Keying ,02 engineering and technology ,Algorithm ,k-nearest neighbors algorithm - Abstract
In this paper, a three-dimensional (3-D) positioning system using fingerprinting and K-Nearest neighbor is proposed. The implementation of the proposed positioning system based on visible light communication (VLC) is discussed. On-off keying (OOK) modulation, Manchester coding and time division multiplexing (TDM) are utilized to obtain both lossless data and accurate received signal strength indications (RSSIs) without sacrificing the comfort of indoor illumination. The proposed 3-D positioning algorithm is conducted in three processes. Firstly, we quickly traverse all sampling points in the fingerprint database to find the nearest neighbor and choose candidate sampling points around the nearest neighbor. Secondly, we conduct an iterative search among candidate sampling points to find K-Nearest neighbors. Finally, we obtain estimated coordinates using weighted average method. Experimental result shows that, the proposed system possesses fast location and high accuracy.
- Published
- 2017
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- View/download PDF
24. Study of Coordinated Set of Coordinated Multi-Point Transmission with Limited Feedback
- Author
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Ming Chen, Ziyan Jia, Mei Zhao, Zhengquan Li, and Jianxin Dai
- Subjects
Set (abstract data type) ,Transmission (telecommunications) ,Computer Networks and Communications ,Computer science ,Real-time computing ,Electrical and Electronic Engineering ,Software ,Multi point - Published
- 2014
- Full Text
- View/download PDF
25. Performance Analysis of Repetition Coded OFDM Systems with Diversity Combining and Higher-Level Modulation
- Author
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Fumihito Sasamori, Ziyan Jia, Shinjiro Oshita, and Shiro Handa
- Subjects
FREQUENCY OFFSET ,Computer Networks and Communications ,Orthogonal frequency-division multiplexing ,Computer science ,Repetition code ,Link adaptation ,Throughput ,Data_CODINGANDINFORMATIONTHEORY ,Diversity combining ,Computer Science::Networking and Internet Architecture ,Electronic engineering ,Fading ,Maximal-ratio combining ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,business.industry ,Spectral efficiency ,Code rate ,TIME ,DOPPLER SPREAD ,FADING CHANNELS ,Modulation ,Bit error rate ,COFDM ,DATA-TRANSMISSION ,Telecommunications ,business ,Software ,Multipath propagation - Abstract
Orthogonal frequency division multiplexing (OFDM) communication systems have great advantages, such as high spectrum efficiency and robustness against multipath fading. In order to enhance the advantages, this paper investigates an efficient utilization of both diversity combining and higher-level modulation (adaptive modulation) with a repetition code on the frequency domain in the OFDM systems. The repetition coded OFDM systems can achieve an improvement of performance with such a simple structure as one pair of transmit/receive antennas. In this paper, we derive simple closed-form equations for bit error probability (BEP) and throughput, and then improvements of those performances in the proposed OFDM systems are verified by both theoretical analysis and Monte Carlo simulation., Article, IEICE TRANSACTIONS ON COMMUNICATIONS. E94B(1):194-202 (2011)
- Published
- 2011
- Full Text
- View/download PDF
26. Noncoherent Maximum Likelihood Detection for Differential Spatial Multiplexing MIMO Systems
- Author
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Fumihito Sasamori, Shiro Handa, Katsunobu Yoshii, Shinjiro Oshita, and Ziyan Jia
- Subjects
Noise power ,Computer Networks and Communications ,Estimation theory ,Computer science ,Maximum likelihood ,Transmitter ,MIMO ,Data_CODINGANDINFORMATIONTHEORY ,spatial multiplexing ,Spatial multiplexing ,Channel state information ,noncoherent maximum likelihood detection ,multiple-symbol differential detection ,Statistics ,Bit error rate ,Fading ,fast calculation algorithm ,Electrical and Electronic Engineering ,Algorithm ,Software ,Computer Science::Information Theory - Abstract
In this paper, we propose a novel noncoherent maximum likelihood detection (NMLD) method for differential spatial multiplexing (SM) multiple-input multiple-output (MIMO) systems. Unlike the conventional maximum likelihood detection (MLD) method which needs the knowledge of channel state information (CSI) at the receiver, WILD method has no need of CSI at either the transmitter or receiver. After repartitioning the observation block of multiple-symbol differential detection (MSDD) and following a decision feedback process, the decision metric of NMLD is derived by reforming that of MSDD. Since the maximum Doppler frequency and noise power are included in the derived decision metric, estimations of both maximum Doppler frequency and noise power are needed at the receiver for NMLD. A fast calculation algorithm (FCA) is applied to reduce the computational complexity of NMLD. The feasibility of the proposed WILD is demonstrated by computer simulations in both slow and fast fading environments. Simulation results show that the proposed NMLD has good bit error rate (BER) performance, approaching that of the conventional coherent MILD with the extension of reference symbols interval. It is also proved that the BER performance is not sensitive to the estimation errors in maximum Doppler frequency and noise power., Article, IEICE TRANSACTIONS ON COMMUNICATIONS. E93B(2):361-368 (2010)
- Published
- 2010
- Full Text
- View/download PDF
27. MSMiner—a developing platform for OLAP
- Author
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Liangxi Qin, Ziyan Jia, Li Da Xu, Jiayou Li, Zhongzhi Shi, Lei Zhao, Huijing Huang, Qing He, Shaohui Liu, and Youping Huang
- Subjects
Flexibility (engineering) ,Decision support system ,Information Systems and Management ,Database ,Competitive intelligence ,Computer science ,business.industry ,Online analytical processing ,InformationSystems_DATABASEMANAGEMENT ,computer.software_genre ,Data warehouse ,Management Information Systems ,Information extraction ,Arts and Humanities (miscellaneous) ,Business intelligence ,Developmental and Educational Psychology ,business ,Software engineering ,computer ,Information Systems - Abstract
Since the early 1970s, decision support systems (DSS) have evolved significantly. In this paper, the design and implementation of MSMiner, a developing platform for DSS, is introduced. The system is constructed on a data warehouse and integrated with a number of data mining algorithms. It is well suited for on-line analytical processing (OLAP). The characteristics of MSMiner include the ability to support multiple data sources and data mining strategies, additional organizational flexibility in regard to data and mining strategies, and the powerful expansibility of data mining tasks.
- Published
- 2007
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- View/download PDF
28. Basic study of multiple symbol differential detection for SC-FDMA system
- Author
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Lin Shen, Qiuye Li, and Ziyan Jia
- Subjects
Computer science ,Frequency domain ,Metric (mathematics) ,Electronic engineering ,Bit error rate ,Time domain ,Differential (infinitesimal) ,Algorithm ,Symbol (chemistry) - Abstract
In this paper, multiple-symbol differential detection (MSDD) is applied to the differential single-carrier frequency-division multiple access (SC-FDMA) system. Both time domain and frequency domain MSDD are investigated to compensate for the performance loss of conventional differential detection comparing with coherent detection. The decision metric of time and frequency domain MSDD for SC-FDMA are derived respectively. Simulation results demonstrate the effectiveness of MSDD in some situations.
- Published
- 2015
- Full Text
- View/download PDF
29. A hybrid indoor positioning system based on UWB and inertial navigation
- Author
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Kai He, Ziyan Jia, Yaping Zhu, Weiwei Xia, Yueyue Zhang, and Lianfeng Shen
- Subjects
Indoor positioning system ,Computer science ,Real-time computing ,Dead reckoning ,Path (graph theory) ,Computer Science::Networking and Internet Architecture ,Trajectory ,Inertial navigation system ,Simulation - Abstract
The paper illustrates to integrate UWB technology with inertial navigation, and introduces the design of the hybrid indoor positioning system including server, gateway and sensor nodes. A linear regression matrix model is proposed to modify inertial navigation path. Least squares method is used to determine equations relating UWB trajectories to inertial navigation trajectories. Experimental results are shown to compare error distributions of hybrid algorithm and pure UWB solution.
- Published
- 2015
- Full Text
- View/download PDF
30. Research of path loss exponent and distance estimation based on Doppler effect and frequency diversity
- Author
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Jing Hu, Ziyan Jia, Wenqian Huang, Xu Min, and Lianfeng Shen
- Subjects
symbols.namesake ,Vehicular ad hoc network ,Signal strength ,business.industry ,Computer science ,symbols ,business ,Doppler effect ,Path loss exponent ,Algorithm ,Computer network ,Diversity scheme - Abstract
With the need of localization based services increasing, many algorithms are proposed using distance between two points and path loss exponent of the environment. In this paper, we propose an algorithm using received signal strength, Doppler Effect and frequency diversity in vehicular networks. The algorithm can estimate the path loss exponent and distance dynamically in mobile communication environment. And the higher the relative speed of vehicles, the better performance of the propose technique. We evaluate the performance of the proposed algorithm in the simulation and discuss the corresponding results.
- Published
- 2015
- Full Text
- View/download PDF
31. Adaptive blind equalization for differential SC-FDMA system
- Author
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Ming Wu, Ziyan Jia, and Lianfeng Shen
- Subjects
Orthogonal frequency-division multiplexing ,Modulation ,Computer science ,Frequency domain ,Electronic engineering ,Fading ,Frequency domain equalization ,Time domain ,Differential (infinitesimal) ,Blind equalization - Abstract
In this paper, an adaptive blind equalization method is proposed for differential single-carrier frequency-division multiple access (SC-FDMA) system. Both time domain equalizer and frequency domain equalizer are investigated to combat the frequency selective fading. Simulation results show both the time domain and frequency domain equalization can improve the performance of differential SC-FDMA system in frequency selective fading channels.
- Published
- 2015
- Full Text
- View/download PDF
32. Intelligence Chinese Document Semantic Indexing System
- Author
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Ziyan Jia, Zhongzhi Shi, Jiayou Li, and Qing He
- Subjects
Information retrieval ,Explicit semantic analysis ,Information space ,Computer science ,Document classification ,Search engine indexing ,Computer Science (miscellaneous) ,Vector space model ,Relevance (information retrieval) ,Document retrieval ,Document clustering ,computer.software_genre ,computer - Abstract
With the rapid growth of the Internet, how to get information from this huge information space becomes an even more important problem. In this paper, An Intelligence Chinese Document Semantic Indexing System; ICDSIS, is proposed. Some new technologies are integrated in ICDSIS to obtain good performance. ICDSIS is composed of four key procedures. A parallel, distributed and configurable Spider is used for information gather; a multi-hierarchy document classification approach combining the information gain initially processes gathered web documents; a swarm intelligence based document clustering method is used for information organization; a concept-based retrieval interface is applied for user interactive retrieval. ICDSIS is an all-sided solution for information retrieval on the Internet.
- Published
- 2003
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- View/download PDF
33. Differential coding and detection methods in SC-FDMA systems
- Author
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Ziyan Jia and Lianfeng Shen
- Subjects
Orthogonal frequency-division multiplexing ,Computer science ,Frequency domain ,Discrete frequency domain ,Transmitter ,Process (computing) ,Electronic engineering ,Data_CODINGANDINFORMATIONTHEORY ,Time domain ,Differential coding ,Algorithm ,Discrete Fourier transform - Abstract
In this paper, the differential encoding and detection methods in single-carrier frequency-division multiple access (SC-FDMA) systems are investigated. Like in OFDM systems, the differential encoding can be performed in time-domain or frequency-domain in SC-FDMA systems. Also, we can use differential encoding before or after the discrete Fourier transform (DFT) process. Thus the detail design of transmitter with each of the four differential coding methods and the corresponding detection methods is considered and analyzed.
- Published
- 2014
- Full Text
- View/download PDF
34. Differential unitary space-time-frequency coding for SC-FDMA systems
- Author
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Lianfeng Shen and Ziyan Jia
- Subjects
Computer science ,Diversity gain ,Transmitter ,MIMO ,Electronic engineering ,Space time frequency ,Topology ,Unitary state ,Differential coding ,Computer Science::Information Theory ,Coding (social sciences) - Abstract
In this paper, the differential unitary space-time-frequency coding (DUSTFC) scheme is applied in the single-carrier frequency-division multiple access (SC-FDMA) systems. The structure of transmitter and corresponding receiver is considered. The diversity gain of DUSTFC in SC-FDMA system are confirmed by simulation results in both time-domain and frequency-domain differential coding cases.
- Published
- 2014
- Full Text
- View/download PDF
35. An indoor positioning algorithm for mobile objects based on track smoothing
- Author
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Rui Zhang, Yueyue Zhang, Lianfeng Shen, Weiwei Xia, Miao Weiwei, and Ziyan Jia
- Subjects
Mean squared error ,Computer science ,business.industry ,Track (disk drive) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Kalman filter ,Noise ,Extended Kalman filter ,Range (statistics) ,Computer vision ,Artificial intelligence ,business ,Trilateration ,Algorithm ,Smoothing - Abstract
In this paper, a new indoor positioning algorithm is proposed for mobile objects based on track smoothing. Considering the effects of indoor environment and the individual anchor nodes, the algorithm is realized in two filtering phases to modify the UWB range measurements and the trilateration localization results by the Unscented Kalman Filter, which reduces the influence of the additive non-Gaussian noise. Furthermore, the filtered positioning results of a mobile object are smoothed by a proposed adaptive smoothing algorithm, and the accuracy has been significantly improved with the positioning RMSE less than 0.8m and the maximum error is about 1m.
- Published
- 2014
- Full Text
- View/download PDF
36. Variational Bayesian Inference based cooperative spectrum sensing in Cognitive Radio Networks
- Author
-
Ziyan Jia, Tiecheng Song, Ming Wu, and Lianfeng Shen
- Subjects
business.industry ,Computer science ,Astrophysics::High Energy Astrophysical Phenomena ,Spectrum (functional analysis) ,Spectral density ,Estimator ,Coherence (statistics) ,Bayesian inference ,Machine learning ,computer.software_genre ,Radio spectrum ,Cognitive radio ,Frequency domain ,Artificial intelligence ,business ,computer ,Algorithm - Abstract
A novel cooperative spectrum sensing approach is introduced based on a approximate model of the power spectral density (PSD) map in space and frequency domain. This scheme uses a model coefficients estimator based the theory of Variational Bayesian Inference. It reveals the unknown positions of transmitting CRs and the spectrum holes in authorized frequency bands, by capitalizing on the forms of sparsity in Cognitive Radio Networks.
- Published
- 2014
- Full Text
- View/download PDF
37. Experimental demonstration of pulse amplitude modulated visible light communications
- Author
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Lianfeng Shen, Weiwei Xia, Ming Wu, and Ziyan Jia
- Subjects
Computer science ,business.industry ,Cross-phase modulation ,Visible light communication ,Optical modulation amplitude ,law.invention ,Photodiode ,Optics ,Pulse-amplitude modulation ,law ,Modulation ,Pulse-position modulation ,Bit error rate ,Telecommunications ,business ,Fluorescent lamp ,Light-emitting diode - Abstract
We experimentally demonstrate a visible light communication (VLC) system using pulse amplitude modulation (PAM). A commercially available phosphorised white LED is used as the optical transmitter and a Si photodiode (PD) is used as the optical receiver. The experiment is mainly implemented in an indoor environment which is influenced by the sunlight and fluorescent lamp. In variant conditions, the experimental results using 4-PAM and 2-PAM (i.e. on-off-keying (OOK)) and the related analysis are reported.
- Published
- 2014
- Full Text
- View/download PDF
38. A hybrid step model and new azimuth estimation method for pedestrian dead reckoning
- Author
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Rui Zhang, Lianfeng Shen, Ziyan Jia, Yaping Zhu, and Weiwei Xia
- Subjects
Azimuth ,Estimation ,Computer science ,business.industry ,Dead reckoning ,Computer vision ,Artificial intelligence ,Pedestrian ,business - Published
- 2014
- Full Text
- View/download PDF
39. The optimal placement method of anchor nodes toward RSS-based localization systems
- Author
-
Lianfeng Shen, Rui Zhang, Weiwei Xia, Jinghong Guo, and Ziyan Jia
- Subjects
Placement method ,Computer science ,business.industry ,Distributed computing ,RSS ,computer.file_format ,business ,computer ,Computer network - Published
- 2014
- Full Text
- View/download PDF
40. The indoor localization method based on the integration of RSSI and inertial sensor
- Author
-
Lianfeng Shen, Ziyan Jia, Rui Zhang, and Weiwei Xia
- Subjects
Inertial frame of reference ,business.industry ,Computer science ,Wind triangle ,Context (language use) ,Kalman filter ,Extended Kalman filter ,Received signal strength indication ,Dead reckoning ,Global Positioning System ,Computer vision ,Artificial intelligence ,business ,Inertial navigation system - Abstract
The research of localization has become a more and more important topic with the popularity of ubiquitous mobile computing. In indoor environment, since the global positioning system (GPS) is disabled, many miniaturized wireless and sensing technologies have shown giant potential in positioning applications such as Inertial Navigation. In this context, this paper present a methodology to locate and track pedestrians accurately in indoor scenarios, the proposed method employs the extended Kalman filter (EKF) to integration Received Signal Strength Indication (RSSI) measurements with the Inertial Navigation technology. Aiming at the cumulative errors existed in Pedestrian Dead Reckoning (PDR) algorithm, this method uses RSSI information as measurement vector of EKF to correct the cumulative errors. Experimental results show that the proposed fusion method can present more reliable positioning estimations.
- Published
- 2014
- Full Text
- View/download PDF
41. A digital voice transmission system based on visible light communication
- Author
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Hui Guo, Ying Zhang, Anhua Ding, and Ziyan Jia
- Subjects
Engineering ,Analog transmission ,business.industry ,Visible light communication ,Transmission system ,computer.file_format ,Transmission (telecommunications) ,Gate array ,Modulation ,Electronic engineering ,business ,Pulse-code modulation ,computer ,Data transmission - Abstract
In this paper, voice transmission is considered in visible light communication (VLC) systems. A digital voice transmission system is designed and analyzed for better quality and capacity than conventional analog voice transmission system. Commercially available white LED is used as the light source in this system, and to fit for the property of it, multi-level pulse code modulation (MPCM) is chosen as the VLC modulation method. A set of system prototype is developed by mainly using the field-programmable gate array (FPGA). Testing results of the prototype show that the system is reasonable and stable.
- Published
- 2013
- Full Text
- View/download PDF
42. Visible light communication system based on multi-level pulse code modulation
- Author
-
Ziyan Jia, Liwei Yuan, and Hui Guo
- Subjects
Amplitude modulation ,Engineering ,Analog transmission ,Pulse-amplitude modulation ,business.industry ,Binary offset carrier modulation ,Pulse-position modulation ,Electronic engineering ,Visible light communication ,business ,Pulse-width modulation ,Data transmission - Abstract
In this paper, to improve the data transmission rate, visible light communication (VLC) system based on multi-level pulse code modulation (MPCM) is considered. This system uses different brightness level of the visible light signals to realize the multi-level modulation, thus a high data transmission rate, which is several times of that in 2-level modulation system, can be achieved. The overall design of the system is firstly considered. Then with 4-level modulation as an example, a set of system prototype is developed. Testing results of the prototype show that the system is reasonable and stable. Therefore, it is proved that applying the MPCM in VLC system is feasible and effective.
- Published
- 2013
- Full Text
- View/download PDF
43. Intercarrier interference suppression method for OFDM systems with multiple-symbol differential detection
- Author
-
Shiro Handa, Fumihito Sasamori, Shinjiro Oshita, and Ziyan Jia
- Subjects
Computer science ,Orthogonal frequency-division multiplexing ,business.industry ,Interval (mathematics) ,Signal-to-noise ratio ,Frequency domain ,Metric (mathematics) ,Computer Science::Networking and Internet Architecture ,Bit error rate ,Fading ,Astrophysics::Earth and Planetary Astrophysics ,Differential (infinitesimal) ,Telecommunications ,business ,Algorithm ,Computer Science::Information Theory ,Communication channel - Abstract
In this paper, an intercarrier interference (ICI) suppression method for frequency domain differential orthogonal frequency division multiplexing (OFDM) systems with multiple symbol differential detection (MSDD) in time-varying frequency-selective fading channels is proposed. The decision metric is derived by considering the statistical effects of ICI from all the subcarriers as well as considering the fading autocorrelations. Knowledges of transmitted signals from both inner and outer subcarriers of an MSDD observation interval can be used to estimate and mitigate the effects of ICI. The effectiveness of the proposed method is demonstrated by computer simulations.
- Published
- 2009
- Full Text
- View/download PDF
44. Multiple-Symbol Differential Detection for Space-Time Block Codes over Fast Rayleigh Fading Channels
- Author
-
Fumihito Sasamori, Shinjiro Oshita, Ziyan Jia, and Shiro Handa
- Subjects
Block code ,Space–time block code ,Channel code ,Theoretical computer science ,Computer science ,Metric (mathematics) ,MIMO ,Fading ,Data_CODINGANDINFORMATIONTHEORY ,Algorithm ,Computer Science::Information Theory ,Rayleigh fading ,Communication channel - Abstract
In this paper, multiple-symbol differential detection (MSDD) for space-time block codes (STBC) is considered over fast Rayleigh fading multiple-input multiple-output (MIMO) channels. The decision metric is derived by considering the fading autocorrelation, and the M-algorithm is adopted to reduce the computational complexity of the decision metric. Simulation results demonstrate that MSDD is effective to fill the performance gap between conventional differential detection and coherent detection of differential STBC by extending the observation interval.
- Published
- 2006
- Full Text
- View/download PDF
45. Multiple-symbol differential detection for space-time block codes with diversity reception
- Author
-
Fumihito Sasamori, Shinjiro Oshita, Ziyan Jia, and Shiro Handa
- Subjects
Block code ,Space–time block code ,Diversity combining ,business.industry ,Computer science ,Space time ,Maximal-ratio combining ,Differential (infinitesimal) ,Telecommunications ,business ,Algorithm ,Symbol (chemistry) ,Diversity (business) - Abstract
In this paper, the diversity reception of differential space-time block coding (STBC) system using multiple-symbol differential detection (MSDD) method with multiple receive antennas is considered. Postdetection maximum ratio combining (MRC), postdetection equal-gain combining (EGC) and predetection selective combining (SC) are used as diversity combining techniques. Their performance is analyzed by computer simulations
- Published
- 2006
- Full Text
- View/download PDF
46. GHUNT: a semantic indexing system based on concept space
- Author
-
Haijun Zhang, Zhongzhi Shi, Qing He, Qingyong Li, Jiayou Li, and Ziyan Jia
- Subjects
Concept search ,Information retrieval ,business.industry ,Emerging technologies ,Computer science ,Information space ,Human–computer information retrieval ,Search engine indexing ,Vector space model ,The Internet ,Computational linguistics ,business - Abstract
How to get text information from this huge information space becomes a more important problem with the rapid growth of the Internet. A semantic indexing system GHUNT based on concept space is proposed to solve the problem. Some new technologies are integrated in GHUNT to obtain good performance. GHUNT is an all-sided solution for information retrieval on the Internet.
- Published
- 2004
- Full Text
- View/download PDF
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