期刊文献+
共找到260,757篇文章
< 1 2 250 >
每页显示 20 50 100
Efficient cache replacement framework based on access hotness for spacecraft processors
1
作者 GAO Xin NIAN Jiawei +1 位作者 LIU Hongjin YANG Mengfei 《中国空间科学技术(中英文)》 CSCD 北大核心 2024年第2期74-88,共15页
A notable portion of cachelines in real-world workloads exhibits inner non-uniform access behaviors.However,modern cache management rarely considers this fine-grained feature,which impacts the effective cache capacity... A notable portion of cachelines in real-world workloads exhibits inner non-uniform access behaviors.However,modern cache management rarely considers this fine-grained feature,which impacts the effective cache capacity of contemporary high-performance spacecraft processors.To harness these non-uniform access behaviors,an efficient cache replacement framework featuring an auxiliary cache specifically designed to retain evicted hot data was proposed.This framework reconstructs the cache replacement policy,facilitating data migration between the main cache and the auxiliary cache.Unlike traditional cacheline-granularity policies,the approach excels at identifying and evicting infrequently used data,thereby optimizing cache utilization.The evaluation shows impressive performance improvement,especially on workloads with irregular access patterns.Benefiting from fine granularity,the proposal achieves superior storage efficiency compared with commonly used cache management schemes,providing a potential optimization opportunity for modern resource-constrained processors,such as spacecraft processors.Furthermore,the framework complements existing modern cache replacement policies and can be seamlessly integrated with minimal modifications,enhancing their overall efficacy. 展开更多
关键词 spacecraft processors cache management replacement policy storage efficiency memory hierarchy MICROARCHITECTURE
下载PDF
An Aggregation Cache Replacement Algorithm Based on Ontology Clustering 被引量:2
2
作者 ZHU Jiang SHEN Qingguo TANG Tang LI Yongqiang 《Wuhan University Journal of Natural Sciences》 CAS 2006年第5期1141-1146,共6页
This paper describes the theory, implementation, and experimental evaluation of an Aggregation Cache Replacement ( ACR ) algorithm. By considering application background, carefully choosing weight values, using a sp... This paper describes the theory, implementation, and experimental evaluation of an Aggregation Cache Replacement ( ACR ) algorithm. By considering application background, carefully choosing weight values, using a special formula to calculate the similarity, and clustering ontologies by similarity for getting more embedded deep relations, ACR combines the ontology similarity with the value of object and decides which object is to be replaced. We demonstrate the usefulness of ACR through experiments. (a) It is found that the aggregation tree is created wholly differently according to the application cases. Therefore, clustering can direct the content adaptation more accurately according to the user perception and can satisfy the user with different preferences. (b) After comparing this new method with widely-used algorithm Last-Recently-Used (LRU) and First-in-First-out (FIFO) method, it is found that ACR outperforms the later two in accuracy and usability. (c) It has a better semantic explanation and makes adaptation more personalized and more precise. 展开更多
关键词 ontology similarity replacement algorithm content adaptation semantic Web
下载PDF
Periodical Inspections and Delay Replacement Model Based on Age Preventive Replacement Policy 被引量:1
3
作者 王文彬 王慧颖 彭锐 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期744-746,752,共4页
Periodical inspections and an age-based preventive replacement( APR) model were proposed based on a two-stage failure process for a single component system. Inspection activities were performed at regular intervals. O... Periodical inspections and an age-based preventive replacement( APR) model were proposed based on a two-stage failure process for a single component system. Inspection activities were performed at regular intervals. Once the system was identified to be at defective state by inspection,a maintenance decision needed to be made that whether to replace the defective system immediately or wait till the preset APR time. So a threshold was introduced into the model and called as inspection-based preventive replacement( IPR) threshold. If the distance from the defect identification point to the APR time was longer than the threshold, a preventive replacement( PR) action was made; otherwise PR action was to wait till the APR time. Two models were proposed and compared,and a numerical example was conducted to illustrate the applicability of the model. 展开更多
关键词 delay-time INSPECTION age-based preventive replacement(APR) inspection-based preventive replacement(IPR) preventive maintenance(PM)
下载PDF
SATELLITE-BASED ANALYSIS ON THE CONCENTRIC EYEWALL REPLACEMENT CYCLES OF SUPER TYPHOON MUIFA (1109) 被引量:1
4
作者 朱雪松 余晖 +2 位作者 毛卓成 徐明 谈建国 《Journal of Tropical Meteorology》 SCIE 2016年第3期330-340,共11页
Multisatellite data is used to analyze the characteristics of three eyewall replacement cycles(ERCs) during the lifetime of Typhoon Muifa(1109).Spiral rainbands evolutions,concentric eyewall(CE) structure modes,CE dur... Multisatellite data is used to analyze the characteristics of three eyewall replacement cycles(ERCs) during the lifetime of Typhoon Muifa(1109).Spiral rainbands evolutions,concentric eyewall(CE) structure modes,CE durations,and intensity changes are discussed in detail.In addition,an ERC evolution model of Typhoon Muifa is given.There are four main findings.(1) The outer spiral rainband joins end to end to form the outer eyewall after it disconnects from the original(inner) eyewall.The inner eyewall weakens as the outer eyewall becomes axisymmetric and is intensified.The contraction of the outer eyewall causes the inner eyewall to dissipate rapidly.Finally,the ERC ends with an annular eyewall or spiral rainbands.(2) Although the CE duration times of Typhoon Muifa's three ERCs covered a large range,the CE structures were all maintained for approximately 5 h from the formation of the axisymmetric outer eyewall to the end of the cycle.(3) There is no obvious precipitation reflectivity in the eye or moat region for the subsidence flow.The convection within the two eyewalls is organized as a radially outward slope with increasing height.(4) Typhoon intensity estimation results based on ADT may not explain the intensity variations associated with ERC correctly,while the typhoon's warm core data retrieved from AMSU-A works well. 展开更多
关键词 SATELLITE data super TYPHOON CONCENTRIC EYEWALL EYEWALL replacement cycle intensity VARIATIONS
下载PDF
Population-Based and Personalized Design of Total Knee Replacement Prosthesis for Additive Manufacturing Based on Chinese Anthropometric Data 被引量:1
5
作者 C.S.Chui K.S.Leung +10 位作者 J.Qin D.Shi P.Augat R.M.Y.Wong S.K.H.Chow X.Y.Huang C.Y.Chen Y.X.Lai P.S.H.Yung L.Qin W.H.Cheung 《Engineering》 SCIE EI 2021年第3期386-394,共9页
At present,most total knee replacement(TKR)prostheses on the market are designed according to the sizes of Caucasians.However,extensive studies have indicated that human anatomies differ among different ethnicities.A ... At present,most total knee replacement(TKR)prostheses on the market are designed according to the sizes of Caucasians.However,extensive studies have indicated that human anatomies differ among different ethnicities.A number of reports have indicated that Chinese TKR patients do not match with available prostheses.In this study,computed tomography(CT)images of 52 knees of Chinese men and women were used for anthropometric measurements.Index and geometric measurements were definedand used for correlation analysis.Key parameters from the measurement results were identified.Detailed geometries of knees were measured as coordinates.A deformable three-dimensional(3D)knee modelbased on anatomical coordinates correlating with the identified key parameters was generated.A pros-thesis was then designed according to the analyzed results.Surface matching analysis,bone resectionanalysis,and cadaveric trials were conducted and compared with commercial products to validate theproposed design.The femoral component designed by this study resulted in the highest accuracy(rootmean square point-to-surface(RMS PS),(1.08±0.20)mm)and lowest amount of resected bone volume(27412mm^(3))in comparison with two commercial knee prostheses.This study suggests a new approachfor population-based patient-specific femoral prosthesis design With a single,easilty acquired dimen-sion-namely,epicondyle width(ECW)-as input,a patient-specific femoral prosthesis can be designed according to the analyzed measured data and manufactured by additive manufacturing(AM)methods.Meanwhile,the reconstructed femoral condylar surface was compared with the femoral condylar surfacein the original CT scanning data The average RMS PS distance of the reconstructed femoral condylar surface among all data was(1.10±0.18)mm,which is comparable to other statistical shape modeling methods using multiple radiographs as input data.There is a need to develop an anthropometric-based knee prosthesis for the Chinese population.Based on the anthropometry of the Chinese population,our new design fits Chinese patients better and reserves more bone volume compared with current commercial prostheses,which is an essential step toward AM for personalized knee prostheses. 展开更多
关键词 Additive manufacturing Population-based design Total knee replacement Knee prosthesis Anthropometric measurement
下载PDF
Prevalence of hypothyroidism and effect of thyroid hormone replacement therapy in patients with non-alcoholic fatty liver disease:A population-based study 被引量:2
6
作者 Ashraf Almomani Asif Ali Hitawala +4 位作者 Prabhat Kumar Sura Alqaisi Dana Alshaikh Motasem Alkhayyat Imad Asaad 《World Journal of Hepatology》 2022年第3期551-558,共8页
BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is currently considered as the most common cause of chronic liver disease worldwide.Risk factors for NAFLD have been well-described,including obesity,type 2 diabetes ... BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is currently considered as the most common cause of chronic liver disease worldwide.Risk factors for NAFLD have been well-described,including obesity,type 2 diabetes mellites(T2DM),dyslipidemia(DLP)and metabolic syndrome.Hypothyroidism has been identified as an independent risk factor for the development of NAFLD,although the literature is inconsistent AIM To evaluate the prevalence of hypothyroidism in patients with NAFLD,assess if it is an independent risk factor and explore the effect of thyroxine replacement therapy.METHODS Our cohort’s data was obtained using a validated,large,multicenter database(Explorys Inc,Cleveland,OH,United States)aggregated from pooled outpatient and inpatient records of 26 different healthcare systems,consisting of a total of 360 hospitals in the United States,and utilizing Systematized Nomenclature of Medicine-Clinical Terms for coding.We evaluated a cohort of patients with hypothyroidism and NAFLD.Multivariate analysis was performed to adjust for confounding risk factors including hypertension(HTN),T2DM,DLP,obesity and metabolic syndrome.SPSS version 25,IBM Corp was used for statistical analysis,and for all analyses,a 2-sided P value of<0.05 was considered statistically significant.Exclusion criteria were limited to age<18 years.RESULTS Among the 37648180 included individuals in this database who are above the age of 18 years,there were a total of 2320 patients with NAFLD(6.16 per 100000)in the last five years(2015-2020),amongst which 520 patients(22.4%)had hypothyroidism.Baseline characteristics of patients in this database are described in Table 1.Patients with NAFLD were also more likely to have obesity,T2DM,DLP,HTN,and metabolic syndrome(Table 2).While males and females were equally affected,patients in the age group 18-65 years as well as Caucasians seem to be at a higher risk.There was an increased risk of NAFLD among patients with hypothyroidism(OR=1.587).Furthermore,thyroid hormone replacement was not associated with a decreased risk for developing NAFLD(OR=1.106,C=0.952-1.285,P=0.303).CONCLUSION Hypothyroidism seems to be an independent risk factor for the development of NAFLD.Thyroid hormone replacement did not provide a statistically significant risk reduction.Further studies are needed to evaluate the effect of thyroid hormone replacement and assess if being euthyroid while on thyroid replacement therapy affects development and/or progression of NAFLD. 展开更多
关键词 HYPOTHYROIDISM Non-alcoholic fatty liver disease Thyroid hormone replacement therapy Independent risk factor
下载PDF
A Cache Replacement Policy Based on Multi-Factors for Named Data Networking 被引量:1
7
作者 Meiju Yu Ru Li Yuwen Chen 《Computers, Materials & Continua》 SCIE EI 2020年第10期321-336,共16页
Named Data Networking(NDN)is one of the most excellent future Internet architectures and every router in NDN has the capacity of caching contents passing by.It greatly reduces network traffic and improves the speed of... Named Data Networking(NDN)is one of the most excellent future Internet architectures and every router in NDN has the capacity of caching contents passing by.It greatly reduces network traffic and improves the speed of content distribution and retrieval.In order to make full use of the limited caching space in routers,it is an urgent challenge to make an efficient cache replacement policy.However,the existing cache replacement policies only consider very few factors that affect the cache performance.In this paper,we present a cache replacement policy based on multi-factors for NDN(CRPM),in which the content with the least cache value is evicted from the caching space.CRPM fully analyzes multi-factors that affect the caching performance,puts forward the corresponding calculation methods,and utilize the multi-factors to measure the cache value of contents.Furthermore,a new cache value function is constructed,which makes the content with high value be stored in the router as long as possible,so as to ensure the efficient use of cache resources.The simulation results show that CPRM can effectively improve cache hit ratio,enhance cache resource utilization,reduce energy consumption and decrease hit distance of content acquisition. 展开更多
关键词 Cache replacement policy named data networking content popularity FRESHNESS energy consumption
下载PDF
Research on replacement depth of black cotton soil based on cracking behavior of embankment 被引量:1
8
作者 Cheng Yongzhen Huang Xiaoming 《Journal of Southeast University(English Edition)》 EI CAS 2020年第4期436-443,共8页
In order to analyze the influence of replacement depth of black cotton soil(BCS)foundation on the initial cracking depth of a highway embankment,the laboratory tests were performed to construct the constitutive relati... In order to analyze the influence of replacement depth of black cotton soil(BCS)foundation on the initial cracking depth of a highway embankment,the laboratory tests were performed to construct the constitutive relationship between state variables and stress variables of BCS,and the coupled consolidation theory for unsaturated soils was employed to simulate the change in the major principal stress of the subgrade soils caused by water loss shrinkage of BCS with the help of Abaqus 6.11 codes.The simulation results indicate that the water losing shrinkage of BCS causes tensile stress within the subgrade,which leads to embankment cracking.The crack depth decreases with the increase in the BCS replacement depth and the embankment height,and increases with the increase in the burial depth of BCS.In the distribution area of deep BCS,the key values of foundation replacement depth for controlling the crack depth of the embankment with the height of 1 to 4 m are 1.2 and 1.5 m.In the low filling section,when the buried depth of BCS is 2,3 and 4 m,the key values of the foundation replacement depth to control the crack depth of the embankment are 0.8 and 1.2 m.In order to control the embankment cracking induced by the water losing shrinkage of BCS,a reasonable replacement depth of the foundation should be selected while slope protection is carried out well. 展开更多
关键词 black cotton soil coupled consolidation theory for unsaturated soils major principal stress embankment crack replacement depth
下载PDF
Optimal Replacement Time of Electrical Components Based on Constant-Interval Replacement Model: Equipment Inspection Method and Weibull Analysis
9
作者 Ohn Zin Lin Hajime Miyauchi 《Energy and Power Engineering》 2017年第4期475-485,共11页
The operation of distribution system with the components in deteriorating condition makes the system reliability worsen. It is important to find the solution for balancing failure cost and maintenance benefits such as... The operation of distribution system with the components in deteriorating condition makes the system reliability worsen. It is important to find the solution for balancing failure cost and maintenance benefits such as down-time and reliability. In this paper, time to replace the components in optimum condition based on constant-interval replacement mode is investigated. The optimal replacement time is mainly depended on component’s reliability and the cost ration of preventive replacement and failure replacement. In this paper, equipment inspection method and Weibull Analysis is applied to obtain the accurate reliability estimation. Weibull Analysis is applied with constant-interval replacement model to investigate the optimum replacement time for each component considering the different cost ratios. According to the quantitative results, the determination of the optimal replacement time (OPT) can minimize the total downtime and failure cost. Consequently, the reliability of the system is maximized and estimation also becomes more accurate due to sufficient approach. 展开更多
关键词 OPTIMAL replacement Reliability COST INSPECTION Weibull Distribution
下载PDF
A Transformer Replacement Decision Method Based on Probability Assessment of Failure Rate
10
作者 Gang Liang Shengwei Li +3 位作者 Yan Qi Jing Cao Yi Hao Wenfu Chen 《Energy and Power Engineering》 2017年第4期748-755,共8页
Reasonable probability assessment of transformer failure rate (FR) is a critical reference to the transformer replacement work. At present, the lack of support theory for transformer replacement usually causes reliabi... Reasonable probability assessment of transformer failure rate (FR) is a critical reference to the transformer replacement work. At present, the lack of support theory for transformer replacement usually causes reliability and economy issues for power companies. For this reason, a transformer replacement decision method based on probability assessment of FR is proposed. Firstly, a first order model of transformer paper degradation is proposed. Then, the Weibull Distribution is used by Monte Carlo Simulation (MCS) to generate the variations of Degree of Polymerization (DP) along with time based on the historical data, and the transformer FR is determined. When the FR is higher than a pre-defined threshold value, the transformer should be replaced for reliability purpose. Finally, the effectiveness of the proposed method for the transformer replacement decision is verified by a typical engineering application. 展开更多
关键词 TRANSFORMER replacement PROBABILITY Assessment Weibull DISTRIBUTION DEGREE of POLYMERIZATION
下载PDF
A method to calculate the acetabular cup anteversion after total hip replacement based on 3D coordinate system
11
作者 Zhenhua Zhang Fujie Sun +3 位作者 Jie Li Hongbiao Li Yiqi Deng Guodong Yin 《Journal of Biomedical Science and Engineering》 2013年第10期964-966,共3页
Aim: To explore an accurate method to calculate acetabular cup anteversion after total hip arthroplasty. Method: 1) A 3D coordinate system was established with the center of the hip joint rotation center base as coord... Aim: To explore an accurate method to calculate acetabular cup anteversion after total hip arthroplasty. Method: 1) A 3D coordinate system was established with the center of the hip joint rotation center base as coordinate center. The acetabular exit plane and Pettersson formula acetabular anteversion and Riten Pradhan formula acetabular anteversion and acetabular true anteversion were drawn;2) Determine the mathematical expression of Pettersson formula acetabular anteversion α and Riten Pradhan formula acetabular anteversion β in the coordinate system. The true acetabular anteversion is projection angle of Pettersson formula acetabular anteversion α on cross-section in the presence of acetabular abduction δ, determining mathematical expression of the acetabular anteversion θ by trigonometric functions. Results: Real acetabular cup anteversion θ = arctg (tgβ/cosδ). Conclusion: The true acetabular cup anteversion and Pettersson formula anteversion and Riten Pradhan for mula anteversion were quite different. The difference was increased with the acetabular cup abduction angle increased. The formula was simple and accurate and worthy of clinical reference. 展开更多
关键词 HIP JOINT replacement ACETABULAR ANTEVERSION Calculation FORMULA
下载PDF
Effects of hormone replacement therapy on mood and sleep quality in menopausal women 被引量:2
12
作者 Qing Liu Zhen Huang Ping Xu 《World Journal of Psychiatry》 SCIE 2024年第7期1087-1094,共8页
BACKGROUND Hormone replacement therapy is an effective treatment strategy for the management of symptoms in naturally menopausal women.However,some patients report experiencing adverse effects.AIM To analyze the effec... BACKGROUND Hormone replacement therapy is an effective treatment strategy for the management of symptoms in naturally menopausal women.However,some patients report experiencing adverse effects.AIM To analyze the effects of hormone replacement therapy in menopausal female patients.METHODS A total of 152 menopausal female patients admitted to the Gynecology Department of the Ganzhou Maternal and Child Health Hospital between January 2021 and December 2023 were divided into the observation group(n=76,conventional treatment+hormone replacement therapy)and the control group(n=76,conventional treatment only)via random casting.The improvement observed in the following items were compared between the groups:Kupperman menopausal index(KMI),emotional state[The Positive and Negative Affect Scale(PANAS)],sleep quality[Self-Rating Scale of Sleep(SRSS)],treatment effectiveness,and treatment safety.RESULTS The modified KMI and SRSS scores of the observation group were lower than those of the control group after three rounds of treatment.The improvement in the PANAS score observed in the observation group was greater than that observed in the control group(P<0.05).The total treatment effectivity rate in the observation group was higher than that in the control group(86.84%vs 96.05%,χ2=4.121,P=0.042).The incidence rate of adverse reactions in the two groups was comparable(6.58%vs 9.21%,χ2=0.361,P=0.547).CONCLUSION Hormone replacement therapy effectively improved the clinical symptoms,actively channeled negative emotions,and improved the quality of sleep in menopausal patients,indicating its effectiveness and safety. 展开更多
关键词 Hormone replacement therapy MENOPAUSE WOMEN Mood states Sleep quality Sex hormones
下载PDF
Generation of mitochondrial replacement monkeys by female pronucleus transfer 被引量:1
13
作者 Chun-Yang Li Xing-Chen Liu +6 位作者 Yu-Zhuo Li Yan Wang Yan-Hong Nie Yu-Ting Xu Xiao-Tong Zhang Yong Lu Qiang Sun 《Zoological Research》 SCIE CSCD 2024年第2期292-298,共7页
Mutations in mitochondrial DNA(mtDNA)are maternally inherited and have the potential to cause severe disorders.Mitochondrial replacement therapies,including spindle,polar body,and pronuclear transfers,are promising st... Mutations in mitochondrial DNA(mtDNA)are maternally inherited and have the potential to cause severe disorders.Mitochondrial replacement therapies,including spindle,polar body,and pronuclear transfers,are promising strategies for preventing the hereditary transmission of mtDNA diseases.While pronuclear transfer has been used to generate mitochondrial replacement mouse models and human embryos,its application in non-human primates has not been previously reported.In this study,we successfully generated four healthy cynomolgus monkeys(Macaca fascicularis)via female pronuclear transfer.These individuals all survived for more than two years and exhibited minimal mtDNA carryover(3.8%–6.7%),as well as relatively stable mtDNA heteroplasmy dynamics during development.The successful establishment of this nonhuman primate model highlights the considerable potential of pronuclear transfer in reducing the risk of inherited mtDNA diseases and provides a valuable preclinical research model for advancing mitochondrial replacement therapies in humans. 展开更多
关键词 Non-human primates Mitochondrial replacement Female pronuclear transfer
下载PDF
A Predicted Region based Cache Replacement Policy for Location Dependent Data in Mobile Environment
14
作者 Ajey KUMAR Manoj MISRA Anil K. SARJE 《International Journal of Communications, Network and System Sciences》 2008年第1期79-94,共16页
Caching frequently accessed data items on the mobile client is an effective technique to improve the system performance in mobile environment. Proper choice of cache replacement technique to find a suitable subset of ... Caching frequently accessed data items on the mobile client is an effective technique to improve the system performance in mobile environment. Proper choice of cache replacement technique to find a suitable subset of items for eviction from cache is very important because of limited cache size. Available policies do not take into account the movement patterns of the client. In this paper, we propose a new cache replacement policy for location dependent data in mobile environment. The proposed policy uses a predicted region based cost function to select an item for eviction from cache. The policy selects the predicted region based on client’s movement and uses it to calculate the data distance of an item. This makes the policy adaptive to client’s movement pattern unlike earlier policies that consider the directional / non-directional data distance only. We call our policy the Prioritized Predicted Region based Cache Replacement Policy (PPRRP). Simulation results show that the proposed policy significantly improves the system performance in comparison to previous schemes in terms of cache hit ratio. 展开更多
关键词 Mobile Computing CACHE replacement LOCATION DEPENDENT Data VALID SCOPE LOCATION DEPENDENT Information Services.
下载PDF
Replacement Strategy for Aged Transformers Based on Condition Monitoring and System Risk 被引量:1
15
作者 Dabo ZHANG Wenyuan LI Xiaofu XIONG 《电力系统自动化》 EI CSCD 北大核心 2013年第17期64-71,共8页
关键词 系统风险 替换策略 状态监测 变形金刚 老年 老化故障 风险评估 变压器
下载PDF
Current knowledge for the risk factors of early permanent pacemaker implantation following transcatheter aortic valve replacement and what is next for the primary prevention? 被引量:1
16
作者 Gen-Min Lin Wei-Chun Huang Chih-Lu Han 《World Journal of Cardiology》 2024年第2期54-57,共4页
In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from... In this editorial,we comprehensively summarized the preoperative risk factors of early permanent pacemaker implantation after transcatheter aortic valve replacement(TAVR)among patients with severe aortic stenosis from several renowned clinical studies and focused on the primary prevention of managing the modifiable factors,e.g.,paroxysmal atrial fibrillation before the TAVR. 展开更多
关键词 Permanent pacemaker implantation Transcatheter aortic valve replacement Interventricular conduction delay DIABETES Supraventricular arrhythmia
下载PDF
Optimal C-arm angulation during transcatheter aortic valve replacement: Accuracy of a rotational C-arm computed tomography based three dimensional heart model
17
作者 Verena Veulemans Sabine Mollus +7 位作者 Axel Saalbach Max Pietsch Katharina Hellhammer Tobias Zeus Ralf Westenfeld Jürgen Weese Malte Kelm Jan Balzer 《World Journal of Cardiology》 CAS 2016年第10期606-614,共9页
AIMTo investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).METHODSRotational C-arm CT (RCT) under rapid ... AIMTo investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).METHODSRotational C-arm CT (RCT) under rapid ventricular pacing was performed in 57 consecutive patients with severe aortic stenosis as part of the pre-procedural cardiac catheterization. With prototype software each RCT data set was segmented using a 3D heart model. From that the line of perpendicularity curve was obtained that generates a perpendicular view of the aortic annulus according to the right-cusp rule. To evaluate the accuracy of a model-based overlay we compared model- and expert-derived aortic root diameters.RESULTSFor all 57 patients in the RCT cohort diameter measurements were obtained from two independent operators and were compared to the model-based measurements. The inter-observer variability was measured to be in the range of 0&#x000b0;-12.96&#x000b0; of angular C-arm displacement for two independent operators. The model-to-operator agreement was 0&#x000b0;-13.82&#x000b0;. The model-based and expert measurements of aortic root diameters evaluated at the aortic annulus (r = 0.79, P &#x0003c; 0.01), the aortic sinus (r = 0.93, P &#x0003c; 0.01) and the sino-tubular junction (r = 0.92, P &#x0003c; 0.01) correlated on a high level and the Bland-Altman analysis showed good agreement. The interobserver measurements did not show a significant bias.CONCLUSIONAutomatic segmentation of the aortic root using an anatomical model can accurately predict an optimal C-arm configuration, potentially simplifying current clinical workflows before and during TAVR. 展开更多
关键词 Aortic stenosis Imaging modalities Degenerative valve disease Transcatheter aortic valve replacement
下载PDF
A comprehensive review of lunar lava tube base construction and field research on a potential Earth test site 被引量:1
18
作者 Yujie Feng Peng-Zhi Pan +3 位作者 Xuhai Tang Zhaofeng Wang Yuxin Li Altaf Hussain 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第9期1201-1216,共16页
The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission... The Moon,as the closest celestial body to the Earth,plays a pivotal role in the progression of deep space exploration,and the establishment of research outposts on its surface represents a crucial step in this mission.Lunar lava tubes are special underground caves formed by volcanic eruptions and are considered as ideal natural shelters and scientific laboratories for lunar base construction.This paper begins with an in-depth overview of the geological origins,exploration history,and distribution locations of lunar lava tubes.Subsequently,it delves into the presentation of four distinctive advantages and typical concepts for constructing bases within lava tubes,summarizing the ground-based attempts made thus far in lunar lava tube base construction.Field studies conducted on a lava tube in Hainan revealed rock compositions similar to those found during the Apollo missions and clear lava tube structures,making it a promising analog site.Lastly,the challenges and opportunities encountered in the field of geotechnical engineering regarding the establishment of lunar lava tube bases are discussed,encompassing cave exploration technologies,in-situ testing methods,geomechanical properties under lunar extreme environments,base design and structural stability assessment,excavation and reinforcement techniques,and simulated Earth-based lava tube base. 展开更多
关键词 Lunar lava tube Lunar base construction Extraterrestrial cave exploration Earth analog site
下载PDF
Component reallocation and system replacement maintenance based on availability and cost in series systems
19
作者 FU Yuqiang MA Xiaoyang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第6期1342-1353,共12页
Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation components.This paper studies a CR and system replacement maintenanc... Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation components.This paper studies a CR and system replacement maintenance policy of series repairable systems,which undergoes minimal repairs for each emergency failure of components,and considers constant downtime and cost of minimal repair,CR and system replacement.Two binary mixed integer nonlinear programming models are respectively established to determine the assignment of CR,and the uptime right before CR and system replacement with the objective of minimizing the system average maintenance cost and maximizing the system availability.Further,we derive the optimal uptime right before system replacement with maximization of the system availability,and then give the relationship between the system availability and the component failure rate.Finally,numerical examples show that the CR and system replacement maintenance policy can effectively reduce the system average maintenance cost and improve the system availability,and further give the sensitivity analysis and insights of the CR and system replacement maintenance policy. 展开更多
关键词 component reallocation(CR) system replacement maintenance cost AVAILABILITY binary mixed integer nonlinear programming minimal repair
下载PDF
Imaging characteristics and treatment strategies for carotid artery occlusion caused by skull base fracture:Three case reports 被引量:1
20
作者 Pei-Xin Shangguan Ke-Chun Zhou 《World Journal of Clinical Cases》 SCIE 2024年第15期2664-2671,共8页
BACKGROUND Traumatic internal carotid artery(ICA)occlusion is a rare complication of skull base fractures,characterized by high mortality and disability rates,and poor prognosis.Therefore,timely discovery and correct ... BACKGROUND Traumatic internal carotid artery(ICA)occlusion is a rare complication of skull base fractures,characterized by high mortality and disability rates,and poor prognosis.Therefore,timely discovery and correct management are crucial for saving the lives of such patients and improving their prognosis.This article retrospectively analyzed the imaging and clinical data of three patients,to explore the imaging characteristics and treatment strategies for carotid artery occlusion,combined with severe skull base fractures.CASE SUMMARY This case included three patients,all male,aged 21,63,and 16 years.They underwent plain film skull computed tomography(CT)examination at the onset of their illnesses,which revealed fractures at the bases of their skulls.Ultimately,these cases were definitively diagnosed through CT angiography(CTA)examinations.The first patient did not receive surgical treatment,only anticoagulation therapy,and recovered smoothly with no residual limb dysfunction(Case 1).The other two patients both developed intracranial hypertension and underwent decompressive craniectomy.One of these patients had high intracranial pressure and significant brain swelling postoperatively,leading the family to choose to take him home(Case 2).The other patient also underwent decompressive craniectomy and recovered well postoperatively with only mild limb motor dysfunction(Case 3).We retrieved literature from PubMed on skull base fractures causing ICA occlusion to determine the imaging characteristics and treatment strategies for this type of disease.CONCLUSION For patients with cranial trauma combined with skull base fractures,it is essential to complete a CTA examination as soon as possible,to screen for blunt cerebrovascular injury. 展开更多
关键词 Skull base fracture Traumatic internal carotid artery occlusion Blunt cerebrovascular injury Imaging Case report
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部