随着电影对极致沉浸式视听体验的发展需求,沉浸式声场记录和重放技术日显重要。本文围绕电影音频制作技术中的声场记录和重放问题,介绍了基于球麦克风阵列的高阶高保真立体声(Higher Order Ambisonics,HOA)分析技术,并针对球麦克风阵列...随着电影对极致沉浸式视听体验的发展需求,沉浸式声场记录和重放技术日显重要。本文围绕电影音频制作技术中的声场记录和重放问题,介绍了基于球麦克风阵列的高阶高保真立体声(Higher Order Ambisonics,HOA)分析技术,并针对球麦克风阵列球谐分解中的低频噪声与高频混叠问题,以及双耳重放技术中的阶数受限问题,给出了相应解决方案,研究表明所提方案可为观众提供更真实、更具沉浸感的声场重放效果,提升了观影体验,在电影音频制作中具有广阔的应用前景。展开更多
Metaheuristic algorithms are pivotal in cloud task scheduling. However, the complexity and uncertainty of the scheduling problem severely limit algorithms. To bypass this circumvent, numerous algorithms have been prop...Metaheuristic algorithms are pivotal in cloud task scheduling. However, the complexity and uncertainty of the scheduling problem severely limit algorithms. To bypass this circumvent, numerous algorithms have been proposed. The Hiking Optimization Algorithm (HOA) have been used in multiple fields. However, HOA suffers from local optimization, slow convergence, and low efficiency of late iteration search when solving cloud task scheduling problems. Thus, this paper proposes an improved HOA called CMOHOA. It collaborates with multi-strategy to improve HOA. Specifically, Chebyshev chaos is introduced to increase population diversity. Then, a hybrid speed update strategy is designed to enhance convergence speed. Meanwhile, an adversarial learning strategy is introduced to enhance the search capability in the late iteration. Different scenarios of scheduling problems are used to test the CMOHOA’s performance. First, CMOHOA was used to solve basic cloud computing task scheduling problems, and the results showed that it reduced the average total cost by 10% or more. Secondly, CMOHOA has been applied to edge fog cloud scheduling problems, and the results show that it reduces the average total scheduling cost by 2% or more. Finally, CMOHOA reduced the average total cost by 7% or more in scheduling problems for information transmission.展开更多
Background:Surgically induced astigmatism(SIA)and corneal high-order aberrations(HOAs)are the two main causes of poor visual quality after cataract surgery.Changes in the parameters of corneal HOAs after cataract surg...Background:Surgically induced astigmatism(SIA)and corneal high-order aberrations(HOAs)are the two main causes of poor visual quality after cataract surgery.Changes in the parameters of corneal HOAs after cataract surgery and their effects on and relationships with changes in corneal curvature have not yet been reported.This study aimed to explore changes in anterior,posterior and total corneal curvature,astigmatism and HOAs after microincision cataract surgery.Methods:Sixty-one age-related cataract patients(61 eyes)were included in this prospective study.The total,anterior and posterior corneal astigmatism and corneal HOAs were analyzed by anterior segment optical coherence tomography(AS-OCT)and iTrace before,one day,one week and three months after 2.2 mm temporal microincision coaxial phacoemulsification to evaluate the changes in anterior,posterior and total corneal curvature,astigmatism and corneal HOAs.Results:The mean J0 and J45 values of anterior,posterior and total corneal curvature obtained by ASOCT showed no statistically significant difference between preoperatively and any postoperative followup.SIA occurred on the anterior,posterior and total corneal surfaces and showed no statistically significant difference at any postoperative follow-up.No significant changes in 3rd-order oblique trefoil,vertical coma or 4th-order spherical aberrations were observed after surgery except for a significant increase in horizontal coma at postoperative day 1(POD1).Conclusions:There were no significant changes in corneal curvature after 2.2 mm temporal microincision coaxial phacoemulsification,and the corneal HOAs were not changed significantly except for the increase in horizontal coma at POD1,which may be one of the main reasons of poor visual quality at POD1 in some cataract patients who have good uncorrected or corrected distance vision.展开更多
Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing th...Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing the effects of coal fires, and their environmental impact. In this study, the spatio-temporal changes of underground coal fires in Khanh Hoa coal field(North-East of Viet Nam) were analyzed using Landsat time-series data during the 2008-2016 period. Based on land surface temperatures retrieved from Landsat thermal data, underground coal fires related to thermal anomalies were identified using the MEDIAN+1.5×IQR(IQR: Interquartile range) threshold technique. The locations of underground coal fires were validated using a coal fire map produced by the field survey data and cross-validated using the daytime ASTER thermal infrared imagery. Based on the fires extracted from seven Landsat thermal imageries, the spatiotemporal changes of underground coal fire areas were analyzed. The results showed that the thermalanomalous zones have been correlated with known coal fires. Cross-validation of coal fires using ASTER TIR data showed a high consistency of 79.3%. The largest coal fire area of 184.6 hectares was detected in 2010, followed by 2014(181.1 hectares) and 2016(178.5 hectares). The smaller coal fire areas were extracted with areas of 133.6 and 152.5 hectares in 2011 and 2009 respectively. Underground coal fires were mainly detected in the northern and southern part, and tend to spread to north-west of the coal field.展开更多
We describe a new species of Rhacophorus based on two adult specimens collected from Hoa Binh Province, northern Vietnam. Rhacophorus hoabinhensis sp. nov. is distinguishable from its congeners on the basis of a combi...We describe a new species of Rhacophorus based on two adult specimens collected from Hoa Binh Province, northern Vietnam. Rhacophorus hoabinhensis sp. nov. is distinguishable from its congeners on the basis of a combination of the following morphological characters： size small （SVL 31.1-32.5 mm in males）; head slightly longer than wide; vomerine teeth absent; snout short （SNL/SVL 0.16）; dorsal skin smooth; forearm and tarsus with dermal fringes; dermal appendage at vent present; webbing formula on fingers I12/3-12/3II1-2III1-1IV and on toes I3/4-1II1/2- IIII1/2-1IVI-1/2V; dorsal surface grey yellow with brown spots; lower jaw region dark grey, throat, chest and belly cream; anterior and posterior thighs, as well as ventral surface of tibia orange. The interspecific uncorrected genetic distances （16S rRNA gene） between the new species from Hoa Binh and other analyzed congeners varied from 9.8% to 17.4%. In the phylogenetic analyses, the new species revealed to be a representative of Rhacophorus and was nested within the R. hoanglienensis-orlovi species group.展开更多
文摘随着电影对极致沉浸式视听体验的发展需求,沉浸式声场记录和重放技术日显重要。本文围绕电影音频制作技术中的声场记录和重放问题,介绍了基于球麦克风阵列的高阶高保真立体声(Higher Order Ambisonics,HOA)分析技术,并针对球麦克风阵列球谐分解中的低频噪声与高频混叠问题,以及双耳重放技术中的阶数受限问题,给出了相应解决方案,研究表明所提方案可为观众提供更真实、更具沉浸感的声场重放效果,提升了观影体验,在电影音频制作中具有广阔的应用前景。
基金supported by the National Natural Science Foundation of China (52275480)the Guizhou Provincial Science and Technology Program of Qiankehe Zhongdi Guiding ([2023]02)+1 种基金the Guizhou Provincial Science and Technology Program of Qiankehe Platform Talent Project (GCC[2023]001)the Guizhou Provincial Science and Technology Project of Qiankehe Platform Project (KXJZ[2024]002).
文摘Metaheuristic algorithms are pivotal in cloud task scheduling. However, the complexity and uncertainty of the scheduling problem severely limit algorithms. To bypass this circumvent, numerous algorithms have been proposed. The Hiking Optimization Algorithm (HOA) have been used in multiple fields. However, HOA suffers from local optimization, slow convergence, and low efficiency of late iteration search when solving cloud task scheduling problems. Thus, this paper proposes an improved HOA called CMOHOA. It collaborates with multi-strategy to improve HOA. Specifically, Chebyshev chaos is introduced to increase population diversity. Then, a hybrid speed update strategy is designed to enhance convergence speed. Meanwhile, an adversarial learning strategy is introduced to enhance the search capability in the late iteration. Different scenarios of scheduling problems are used to test the CMOHOA’s performance. First, CMOHOA was used to solve basic cloud computing task scheduling problems, and the results showed that it reduced the average total cost by 10% or more. Secondly, CMOHOA has been applied to edge fog cloud scheduling problems, and the results show that it reduces the average total scheduling cost by 2% or more. Finally, CMOHOA reduced the average total cost by 7% or more in scheduling problems for information transmission.
基金the Construction Project of High-Level Hospitals in Guangdong Province(No.303020102)the National Natural Science Foundation of China(Nos.81900815+1 种基金81873675)the Fundamental Research Funds of the State Key Laboratory of Ophthalmology(No.2019QN06).
文摘Background:Surgically induced astigmatism(SIA)and corneal high-order aberrations(HOAs)are the two main causes of poor visual quality after cataract surgery.Changes in the parameters of corneal HOAs after cataract surgery and their effects on and relationships with changes in corneal curvature have not yet been reported.This study aimed to explore changes in anterior,posterior and total corneal curvature,astigmatism and HOAs after microincision cataract surgery.Methods:Sixty-one age-related cataract patients(61 eyes)were included in this prospective study.The total,anterior and posterior corneal astigmatism and corneal HOAs were analyzed by anterior segment optical coherence tomography(AS-OCT)and iTrace before,one day,one week and three months after 2.2 mm temporal microincision coaxial phacoemulsification to evaluate the changes in anterior,posterior and total corneal curvature,astigmatism and corneal HOAs.Results:The mean J0 and J45 values of anterior,posterior and total corneal curvature obtained by ASOCT showed no statistically significant difference between preoperatively and any postoperative followup.SIA occurred on the anterior,posterior and total corneal surfaces and showed no statistically significant difference at any postoperative follow-up.No significant changes in 3rd-order oblique trefoil,vertical coma or 4th-order spherical aberrations were observed after surgery except for a significant increase in horizontal coma at postoperative day 1(POD1).Conclusions:There were no significant changes in corneal curvature after 2.2 mm temporal microincision coaxial phacoemulsification,and the corneal HOAs were not changed significantly except for the increase in horizontal coma at POD1,which may be one of the main reasons of poor visual quality at POD1 in some cataract patients who have good uncorrected or corrected distance vision.
基金funded by the Ministry-level Scientific and Technological Key Programs of Ministry of Natural Resources and Environment of Viet Nam "Application of thermal infrared remote sensing and GIS for mapping underground coal fires in Quang Ninh coal basin" (Grant No. TNMT.2017.08.06)
文摘Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing the effects of coal fires, and their environmental impact. In this study, the spatio-temporal changes of underground coal fires in Khanh Hoa coal field(North-East of Viet Nam) were analyzed using Landsat time-series data during the 2008-2016 period. Based on land surface temperatures retrieved from Landsat thermal data, underground coal fires related to thermal anomalies were identified using the MEDIAN+1.5×IQR(IQR: Interquartile range) threshold technique. The locations of underground coal fires were validated using a coal fire map produced by the field survey data and cross-validated using the daytime ASTER thermal infrared imagery. Based on the fires extracted from seven Landsat thermal imageries, the spatiotemporal changes of underground coal fire areas were analyzed. The results showed that the thermalanomalous zones have been correlated with known coal fires. Cross-validation of coal fires using ASTER TIR data showed a high consistency of 79.3%. The largest coal fire area of 184.6 hectares was detected in 2010, followed by 2014(181.1 hectares) and 2016(178.5 hectares). The smaller coal fire areas were extracted with areas of 133.6 and 152.5 hectares in 2011 and 2009 respectively. Underground coal fires were mainly detected in the northern and southern part, and tend to spread to north-west of the coal field.
基金supported by the President of the Vietnam Academy of Science and Technology(VAST.CTG.03/16-17)the Ministry of Science and Technology(DLDLXH.19/15)to T.T.Nguyen+1 种基金partially funded by the National Geographic Society(Grant No.9492–14)the Rufford Foundation(Grant No.14877–1)to T.Q.Nguyen
文摘We describe a new species of Rhacophorus based on two adult specimens collected from Hoa Binh Province, northern Vietnam. Rhacophorus hoabinhensis sp. nov. is distinguishable from its congeners on the basis of a combination of the following morphological characters： size small （SVL 31.1-32.5 mm in males）; head slightly longer than wide; vomerine teeth absent; snout short （SNL/SVL 0.16）; dorsal skin smooth; forearm and tarsus with dermal fringes; dermal appendage at vent present; webbing formula on fingers I12/3-12/3II1-2III1-1IV and on toes I3/4-1II1/2- IIII1/2-1IVI-1/2V; dorsal surface grey yellow with brown spots; lower jaw region dark grey, throat, chest and belly cream; anterior and posterior thighs, as well as ventral surface of tibia orange. The interspecific uncorrected genetic distances （16S rRNA gene） between the new species from Hoa Binh and other analyzed congeners varied from 9.8% to 17.4%. In the phylogenetic analyses, the new species revealed to be a representative of Rhacophorus and was nested within the R. hoanglienensis-orlovi species group.
