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Laplacian Speech Model and Soft Decision Based MMSE Estimator for Noise Power Spectral Density in Speech Enhancement

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Chinese Journal of Electronics 2018年第6期27卷 1214-1220页

作者： ou Shifeng SONG Peng GAO Ying School of Science and Technology for Opto-electronic Information Yantai University School of Computer and Control Engineering Yantai University

The estimation of noise Power spectral density(PSD) is a very crucial issue for speech enhancement as a result of its significant effect on the quality and intelligibility of the enhanced speech. Most of the existing estimators for noise PSD try to employ Gaussian speech priors, which, however, have been proven inconsistent with the reality. We derived an effective solution to this problem of estimating noise PSD in the Minimum mean square error(MMSE) sense when the speech component is modeled by a Laplacian distribution. Meanwhile, the soft decision technique instead of the hard Voice activity detection(VAD) is evolved into our algorithm, which can automatically makes the estimation unbiased without requiring a bias compensation. The performance of the proposed method is tested by several objective and subjective measures under various stationary and nonstationary noise environments. The results confirm that our method achieves good performance for all the noise conditions and Signalnoise-ratio(SNR) settings.

关键词： Noise PSD estimation Speech enhancement Laplacian speech model Soft decision

The Nonexistence of the Solutions for the Non-Newtonian Filtration Equation with Absorption

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Journal of Partial Differential Equations 2021年第4期34卷 369-378页

作者： ou Qitong School of Applied Mathematics Xiamen University of TechnologyXiamen 361024China

The paper proves the nonexistence of the solution for the following Cauchy problem{ut=div(|■u^m|(p-2■u^(m)))^-λu^(q),u(x,0)=δ(x),(x,t)∈S_(T)=R^(N)×(0,T),x∈R^(N),under some conditions on m,p,q,λ,whereδis Dirac... 详细信息

关键词： Non-Newtonian filtration equation Cauchy problem nonexistence

Abdominal Trauma during Pregnancy with Splenic Rupture and Fetal Death in Utero at Bogodogo University Hospital: A Case Report

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Open Journal of Obstetrics and Gynecology 2024年第9期14卷 1407-1413页

作者： Yobi Alexis Sawadogo Emmanuel ouédraogo Adama ouattara issa ouédraogo Sibraogo Kiemtoré Charlemagne ouedraogo Department of Obstetrics and Gynaecology Bogodogo University Hospital Ouagadougou Burkina Faso Health Science Training and Research Unit Joseph Ki-Zerbo University Ouagadougou Burkina Faso Department of Obstetrics and Gynaecology Ouahigouya Regional University Hospital Ouahigouya Burkina Faso Department of Obstetrics and Gynaecology Yalgado Oudraogo University Hospital Ouagadougou Burkina Faso

Splenic injury caused by abdominal trauma during pregnancy is rare. Splenic injury associated with fetal death in utero following a fall from a tree top is even rarer. The authors report a case of splenic trauma associated with fetal death in utero following a fall from the top of a tree in a 19-year-old pregnant woman at 30 weeks amenorrhoea. She was referred from a 1st level health facility for trauma that had occurred the day before admission. She was in poor general condition (WHO performance status IV) and had a cardiovascular collapse. Ultrasound was used to diagnose haemoperitoneum and fetal death in utero. A CT scan was used to diagnose splenic lesions. Treatment consisted of splenectomy and caesarean section after resuscitation.

关键词： Trauma Pregnancy Splenic Rupture Stillborn

Investigation of the SA evolution by using the CHAOS-4 model over 1997–2013

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Science China Earth Sciences 2016年第5期59卷 1041-1050页

作者： ou JiaMing DU AiMin XU WenYao Key Laboratory of Earth and Planetary Physics Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences

The temporal and spatial evolution characteristics of the geomagnetic secular acceleration(SA) are investigated, based on CHAOS-4 core field model during the period of 1997–2013. The SA evolution on a short time scale is associated with the phenomenon of the geomagnetic jerk. More details of the global extent and the occurrence time of the successive jerks(the 1999, 2003, 2007, and 2011 jerks) are obtained. The location, size and reversed polarity pattern for the 1999 jerk are similar to those for the 2003 jerk in the Asian-Indian sector. While the 2007 and 2011 jerks mainly take place in the Atlantic sector. The direction and speed of the shift for the four jerks are different, identified by the occurrence time of the jerks. The zonal motions of the SA patches exhibit an oscillation pattern in the Asian-Indian sector, whereas a purely westward drifting pattern is along the equator in the Atlantic sector. It is believed that the shift of the jerks is related to the motion of SA-B_r patches observed at the core-mantle boundary(CMB).

关键词： Geomagnetic secular acceleration Geomagnetic jerk Core-mantle boundary Zonal oscillation

Influence of zeolite and cement additions on mechanical behavior of sandy soil

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Journal of Rock Mechanics and Geotechnical Engineering 2016年第5期8卷 746-752页

作者： Hossein Mola-Abasi issa Shooshpasha Geotechnical Department Babol University of Technology

It is well known that the cemented sand is one of economic and environmental topics in soil stabilization. In this instance, a blend of sand, cement and other materials such as fiber, glass, nanoparticle and zeolite can be commercially available and effectively used in soil stabilization in road construction. However, the influence and effectiveness of zeolite on the properties of cemented sand systems have not been completely explored. In this study, based on an experimental program, the effects of zeolite on the characteristics of cemented sands are investigated. Stabilizing agent includes Portland cement of type II and zeolite. Results show the improvements of unconfined compressive strength （UCS） and failure properties of cemented sand when the cement is replaced by zeolite at an optimum proportion of 30% after 28 days. The rate of strength improvement is approximately between 20% and 78%. The efficiency of using zeolite increases with the increases in cement amount and porosity. Finally, a power function of void-cement ratio and zeolite content is demonstrated to be an appropriate method to assess UCS of zeolite-cemented mixtures.

关键词： ZeoliteCemented sand StrengthUnconfined compressive strength (UCS) Void-cement ratio

Authenticating GNSS civilian signals:a survey

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Satellite Navigation 2023年第1期4卷 196-213,I0006页

作者： Muzi Yuan Xiaomei Tang Gang ou School of Electronic Science National University of Defense TechnologyChangshaChina

Civilian services of Global Navigation Satellite System are threatened by spoofng attacks since it is hard to determine the authenticity of a navigation signal with a detailed structure open to the *** authentication efectively protects the security of the signal by attaching unforgeable information to one or several elements of the *** can verify the authenticity of the signal by extracting and validating this *** good signal authentication schemes requires understanding possible spoofng modes,signal element specialty,and performance evaluation *** paper is an overview of navigation signal authentication,where the theories and reported approaches are described in detail.A design/performance matrix that demonstrates the advantages and defects of the signal element and its authentication design is *** are proposed to improve the robustness,security,efciency,and implementation hardness for future designs of navigation signal authentication.

关键词： GNSS spoofng Signal authentication Signal structure design Authentication scheme

A highly sensitive DNA-AIEgen-based ＂turn-on＂ fluorescence chemosensor for amplification analysis of Hg^2+ ions in real samples and living cells

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Science China Chemistry 2017年第5期60卷 663-669页

作者： Xiaowen ou Xiaoding Lou Fan Xia Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan 430074 China Shenzhen Institute of Huazhong University of Science and Technology Shenzhen 518000 China

Functional nucleic acids(FNAs)-based biosensors have shown great potential in heavy metal ions detection due to their low-cost and easy to operate merits. However, in most FNAs based fluorescence probes, the ingenious designs of double-labeled(fluorophore and quencher group) DNA sequence, not only bring the annoyance of organic synthesis, but also restrict its use as a robust biosensor in practical duties. In this paper, we design a simple AIEgens functional nucleic acids(AFNAs) probe which consists of only fluorogen but no quencher group. With the help of duplex-specific nuclease(DSN) enzyme based target recycling, high fluorescence signal and superior sensitivity towards Hg^(2+) are achieved. This robust assay allows for sensitive and selective detection of Hg^(2+) in real water samples and mapping of intracellular Hg^(2+), without double-labeling of oligonucleotide with a dye-quencher pair, nor the multiple assay steps.

关键词： functional nucleic acids AIEgen Hg2+ detection real samples living cells

Study on the local time asymmetry of the Earth's ring currents based on multiple low-Earth-orbit satellite magnetic observations

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Science China(Technological Sciences) 2024年第11期67卷 3354-3364页

作者： ou JiaMing JIANG Yi YAN Qing State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China Macao Institute of Space Technology and Application Macao 999078China Zhuhai MUST Science and Technology Research Institute Macao University of Science and TechnologyZhuhai 519085China

The azimuthal morphology of Earth's ring currents has consistently shown asymmetry during extreme space weather events at low latitudes,particularly during geomagnetic storms.A dawn-dusk pattern has been detected during the storm main phase through near-Earth and in-situ magnetic *** asymmetry is believed to arise from asymmetric solar windmagnetosphere coupling and is linked to the closure of the ring *** evidence has confirmed the existence of asymmetric ring currents during quiet times and the storm recovery *** phenomenon may be closely related to the evolution of ring currents,including plasma injection and decay *** this study,the local time asymmetry of the ring current is estimated using data from low-Earth-orbit Swarm and Macao Science Satellite-1(MSS-1)*** harmonics models are developed to quantify the magnetic field of ring currents through external Gauss coefficients during both quiet periods and the storm recovery *** features of dawn-dusk asymmetry are observed in various cases in different months.(1)The maximum difference in magnetic value across local time ranges from 3 to 10 nT,showing relative invariance compared with various Sym-H levels.(2)Stronger magnetic signals are detected at the premidnight sector during quiet times and at the afternoon sector during the storm recovery phase.(3)Magnetic perturbations remain at a lower level during the postmidnight and morning *** the pattern of local time asymmetry differs between quiet times and the recovery phase,dawn-dusk asymmetry remains the most pronounced feature,affecting the trapping and loss of charged particles in the inner *** Swarm and MSS-1 magnetic observations can enable convenient monitoring of the detailed azimuthal local time effects of the ring current at various disturbance levels in the future.

关键词： Earth's ring currents local time asymmetry SHA model Macao Science Satellite-1

Role of ERCP in the era of laparoscopic cholecystectomy for the evaluation of choledocholithiasis in sickle cell anemia

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World Journal of Gastroenterology 2011年第14期17卷 1844-1847页

作者： Hussain issa Arabia Ahmed H Al-Salem Department of Internal Medicine King Fahad Specialist HospitalDammamQatif 31911Saudi Department of Pediatric Surgery Maternity and Children HospitalDammamQatif 31911Saudi Arabia

AIM:To evaluate the role of endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis in patients with sickle cell anemia (SCA) in the era of laparoscopic cholecystectomy (LC). METHODS:Two hundred and twenty four patients (144 male,80 female; mean age,22.4 years; range,5-70 years) with SCA underwent ERCP as part of their evaluation for cholestatic jaundice (CJ). The indications for ERCP were:CJ only in 97,CJ and dilated bile ducts on ultrasound in 103,and CJ and common bile duct (CBD) stones on ultrasound in 42. RESULTS:In total,CBD stones were found in 88 (39.3%) patients and there was evidence of recent stone passage in 16. Fifteen were post-LC patients. These had endoscopic sphincterotomy and stone extraction. The remaining 73 had endoscopic sphincterotomy and stone extraction followed by LC without an intraoperative ***:In patients with SCA and cholelithiasis,ERCP is valuable whether preoperative or postoperative,and in none was there a need to perform intraoperative cholangiography. Sequential endoscopic sphincterotomy and stone extraction followed by LC is beneficial in these patients. Endoscopic sphincterotomy may also prove to be useful in these patients as it may prevent the future development of biliary sludge and bile duct stones.

关键词： Sickle cell anemia Cholelithiasis Choledocholithiasis Laparoscopic cholecystectomy Cholangiography Endoscopic retrograde cholangiopancreatography