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Hepatocellular carcinoma Liver Imaging Reporting and Data Systems treatment response assessment: Lessons learned and future directions 被引量:2
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作者 Anum Aslam Richard Kinh Gian Do +7 位作者 Avinash Kambadakone Bradley Spieler Frank H Miller Ahmed M Gabr Resmi A Charalel Charles Y Kim David C Madoff Mishal Mendiratta-Lala 《World Journal of Hepatology》 CAS 2020年第10期738-753,共16页
Hepatocellular carcinoma(HCC)is a leading cause of morbidity and mortality worldwide,with rising clinical and economic burden as incidence increases.There are a multitude of evolving treatment options,including locore... Hepatocellular carcinoma(HCC)is a leading cause of morbidity and mortality worldwide,with rising clinical and economic burden as incidence increases.There are a multitude of evolving treatment options,including locoregional therapies which can be used alone,in combination with each other,or in combination with systemic therapy.These treatment options have shown to be effective in achieving remission,controlling tumor progression,improving disease free and overall survival in patients who cannot undergo resection and providing a bridge to transplant by debulking tumor burden to downstage patients.Following locoregional therapy(LRT),it is crucial to provide treatment response assessment to guide management and liver transplant candidacy.Therefore,Liver Imaging Reporting and Data Systems(LI-RADS)Treatment Response Algorithm(TRA)was created to provide a standardized assessment of HCC following LRT.LIRADS TRA provides a step by step approach to evaluate each lesion independently for accurate tumor assessment.In this review,we provide an overview of different locoregional therapies for HCC,describe the expected post treatment imaging appearance following treatment,and review the LI-RADS TRA with guidance for its application in clinical practice.Unique to other publications,we will also review emerging literature supporting the use of LI-RADS for assessment of HCC treatment response after LRT. 展开更多
关键词 Hepatocellular carcinoma Liver Imaging Reporting and data systems Treatment Response Algorithm Locoregional therapy Liver Imaging Reporting and data systems Treatment Response equivocal Arterial phase hyper enhancement Stereotactic body radiotherapy
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Reliable transmission of consultative committee for space data systems file delivery protocol in deep space communication 被引量:7
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作者 Hui Li Hao Luo Faxin Yu Zheming Lu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第3期349-354,共6页
In consultative committee for space data systems(CCSDS) file delivery protocol(CFDP) recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative ac... In consultative committee for space data systems(CCSDS) file delivery protocol(CFDP) recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative acknowledge and asynchronous negative acknowledge models.CFDP is designed to provide data and storage management,story and forward,custody transfer and reliable end-to-end delivery over deep space characterized by huge latency,intermittent link,asymmetric bandwidth and big bit error rate(BER).Four reliable transmission models are analyzed and an expected file-delivery time is calculated with different trans-mission rates,numbers and sizes of packet data units,BERs and frequencies of external events,etc.By comparison of four CFDP models,the requirement of BER for typical missions in deep space is obtained and rules of choosing CFDP models under different uplink state informations are given,which provides references for protocol models selection,utilization and modification. 展开更多
关键词 deep space communication consultative committee for space data systems (CCSDS) CCSDS file delivery protocol (CFDP) RELIABLE delay.
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AbIx: An Approach to Content-Based Approximate Query Processing in Peer-to-Peer Data Systems
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作者 王朝坤 王建民 +2 位作者 孙家广 石胜飞 高宏 《Journal of Computer Science & Technology》 SCIE EI CSCD 2007年第2期280-286,共7页
In recent years there has been a significant interest in peer-to-peer (P2P) environments in the community of data management. However, almost all work, so far, is focused on exact query processing in current P2P dat... In recent years there has been a significant interest in peer-to-peer (P2P) environments in the community of data management. However, almost all work, so far, is focused on exact query processing in current P2P data systems. The autonomy of peers also is not considered enough. In addition, the system cost is very high because the information publishing method of shared data is based on each document instead of document set. In this paper, abstract indices (AbIx) are presented to implement content-based approximate queries in centralized, distributed and structured P2P data systems. It can be used to search as few peers as possible but get as many returns satisfying users' queries as possible on the guarantee of high autonomy of peers. Also, abstract indices have low system cost, can improve the query processing speed, and support very frequent updates and the set information publishing method. In order to verify the effectiveness of abstract indices, a simulator of 10,000 peers, over 3 million documents is made, and several metrics are proposed. The experimental results show that abstract indices work well in various P2P data systems. 展开更多
关键词 approximate query processing content-based information retrieval peer-to-peer data systems abstract indices
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Automated Performance Tuning of Data Management Systems with Materializations and Indices
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作者 Nan N. Noon Janusz R. Getta 《Journal of Computer and Communications》 2016年第5期46-52,共7页
Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune... Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune the performance of database systems with a little help from the database servers. In this paper, we propose a new technique for automated performance tuning of data management systems. Firstly, we show how to use the periods of low workload time for performance improvements in the periods of high workload time. We demonstrate that extensions of a database system with materialised views and indices when a workload is low may contribute to better performance for a successive period of high workload. The paper proposes several online algorithms for continuous processing of estimated database workloads and for the discovery of the best plan for materialised view and index database extensions and of elimination of the extensions that are no longer needed. We present the results of experiments that show how the proposed automated performance tuning technique improves the overall performance of a data management system.   展开更多
关键词 Automated Performance Tuning Query Processing MATERIALIZATION INDEXING data Management systems
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ASSESSMENT AND OPTIMIZATION OF THE PHASE DIAGRAMS AND THERMODYNAMIC DATA OF SOME BINARY SYSTEMS CONTAINING PRASEODYMIUM CHLORIDES
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作者 乔芝郁 王明生 +1 位作者 郑朝贵 段淑贞 《Journal of Rare Earths》 SCIE EI CAS CSCD 1990年第2期92-98,共7页
In this paper a critical assessment and optimization of the phase diagrams and thermodynamic properties of the PrCl_3-MCl(M=Li,Na)and PrCl_3-MCl_2(M=Mg,Ca,Sr,Ba) binary systems have been per- formed.The assessed and o... In this paper a critical assessment and optimization of the phase diagrams and thermodynamic properties of the PrCl_3-MCl(M=Li,Na)and PrCl_3-MCl_2(M=Mg,Ca,Sr,Ba) binary systems have been per- formed.The assessed and optimized binary phase diagrams and thermodynamic data with self consistency are a better basis for constructing multicomponent phase diagrams. 展开更多
关键词 ASSESSMENT AND OPTIMIZATION OF THE PHASE DIAGRAMS AND THERMODYNAMIC data OF SOME BINARY systems CONTAINING PRASEODYMIUM CHLORIDES
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An image compression method for space multispectral time delay and integration charge coupled device camera
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作者 李进 金龙旭 张然峰 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第6期360-365,共6页
Multispectral time delay and integration charge coupled device (TDICCD) image compression requires a low- complexity encoder because it is usually completed on board where the energy and memory are limited. The Cons... Multispectral time delay and integration charge coupled device (TDICCD) image compression requires a low- complexity encoder because it is usually completed on board where the energy and memory are limited. The Consultative Committee for Space Data Systems (CCSDS) has proposed an image data compression (CCSDS-IDC) algorithm which is so far most widely implemented in hardware. However, it cannot reduce spectral redundancy in mukispectral images. In this paper, we propose a low-complexity improved CCSDS-IDC (ICCSDS-IDC)-based distributed source coding (DSC) scheme for multispectral TDICCD image consisting of a few bands. Our scheme is based on an ICCSDS-IDC approach that uses a bit plane extractor to parse the differences in the original image and its wavelet transformed coefficient. The output of bit plane extractor will be encoded by a first order entropy coder. Low-density parity-check-based Slepian-Wolf (SW) coder is adopted to implement the DSC strategy. Experimental results on space multispectral TDICCD images show that the proposed scheme significantly outperforms the CCSDS-IDC-based coder in each band. 展开更多
关键词 multispectral CCD images Consultative Committee for Space data systems - image data compression (CCSDS-IDC) distributed source coding (DSC)
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ERROR COUNTER-BASED NEGATIVE ACKNOWLEDGEMENT MODE IN CCSDS FILE DELIVERY PROTOCOL
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作者 Xiao Shiiie Yang Mingchuan Guo Qing 《Journal of Electronics(China)》 2011年第2期222-227,共6页
Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in ter... Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in terrestrial communications.Accordingly,the Consultative Committee for Space Data Systems(CCSDS) developed CCSDS File Delivery Protocol(CFDP),which sets standards of efficient file delivery service capable of transferring files to and from mass memory located in the space segment.In CFDP,four optional acknowledge modes are supported to make the communication more reliable.In this paper,we gave a general introduction of typical communication process in CFDP and analysis of its four Negative Acknowledgement(NAK) modes on the respect of file delivery delay and times of retransmission.We found out that despite the shortest file delivery delay,immediate NAK mode suffers from the problem that frequent retransmission may probably lead to network congestion.Thus,we proposed a new mode,the error counter-based NAK mode.By simulation of the case focused on the link between a deep space probe on Mars and a ter-restrial station on Earth,we concluded that error counter-based NAK mode has successfully reduced the retransmission times at negligible cost of certain amount of file delivery delay. 展开更多
关键词 Deep space communication Consultative Committee for Space data systems(CCSDS) File Delivery Protocol(CFDP) Negative AcKnowledgement(NAK) mode
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CloudRank-D: benchmarking and ranking cloud computing systems for data processing applications 被引量:5
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作者 Chunjie LUO Jianfeng ZHAN +5 位作者 Zhen JIA Lei WANG Gang LU Lixin ZHANG Cheng-Zhong XU Ninghui SUN 《Frontiers of Computer Science》 SCIE EI CSCD 2012年第4期347-362,共16页
With the explosive growth of information, more and more organizations are deploying private cloud systems or renting public cloud systems to process big data. However, there is no existing benchmark suite for evaluati... With the explosive growth of information, more and more organizations are deploying private cloud systems or renting public cloud systems to process big data. However, there is no existing benchmark suite for evaluating cloud performance on the whole system level. To the best of our knowledge, this paper proposes the first benchmark suite CloudRank-D to benchmark and rank cloud computing sys- tems that are shared for running big data applications. We an- alyze the limitations of previous metrics, e.g., floating point operations, for evaluating a cloud computing system, and propose two simple metrics: data processed per second and data processed per Joule as two complementary metrics for evaluating cloud computing systems. We detail the design of CloudRank-D that considers representative applications, di- versity of data characteristics, and dynamic behaviors of both applications and system software platforms. Through experi- ments, we demonstrate the advantages of our proposed met- tics. In several case studies, we evaluate two small-scale de- ployments of cloud computing systems using CloudRank-D. 展开更多
关键词 data center systems CLOUDS big data applica- tions benchmarks evaluation metrics
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Access control technologies for Big Data management systems:literature review and future trends 被引量:1
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作者 Pietro Colombo Elena Ferrari 《Cybersecurity》 CSCD 2019年第1期63-75,共13页
Data security and privacy issues are magnified by the volume,the variety,and the velocity of Big Data and by the lack,up to now,of a reference data model and related data manipulation languages.In this paper,we focus ... Data security and privacy issues are magnified by the volume,the variety,and the velocity of Big Data and by the lack,up to now,of a reference data model and related data manipulation languages.In this paper,we focus on one of the key data security services,that is,access control,by highlighting the differences with traditional data management systems and describing a set of requirements that any access control solution for Big Data platforms may fulfill.We then describe the state of the art and discuss open research issues. 展开更多
关键词 Big data Access control PRIVACY NoSQL data management systems
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CALL FOR PAPERS Special Section of JCST on Computer Architecture and Systems for Big Data 被引量:1
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《Journal of Computer Science & Technology》 SCIE EI CSCD 2014年第3期F0003-F0003,共1页
Introduction Research on computer architecture and systems is typically driven by technology and applications. Big data has emerged as an important application domain which has shown its huge impact on scientific rese... Introduction Research on computer architecture and systems is typically driven by technology and applications. Big data has emerged as an important application domain which has shown its huge impact on scientific research, business, and society. Big data is known for its large volume, high velocity, and a variety of formats. The collection, storage, retrieval, processing, and visualization of big data issues many challenges to computer architecture and systems. This special section is an effort to encourage and promote research to address the big data challenges from the computer architecture and systems perspectives. 展开更多
关键词 CALL FOR PAPERS Special Section of JCST on Computer Architecture and systems for Big data
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Synchro Controller of Radar on FPGA
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作者 Jiang Tie-zhen, Shi Zhen-hua, Wu Shi-caiSchool of Electronic Information, Wuhan University, Wuhan 430072,Hubei, China 《Wuhan University Journal of Natural Sciences》 EI CAS 2003年第02A期409-413,共5页
This paper mainly represents the realization of synchro controller based on the programmable logic devices FPGA by request of HF ground wave radar synchro controller under the instance of making the best of the virtue... This paper mainly represents the realization of synchro controller based on the programmable logic devices FPGA by request of HF ground wave radar synchro controller under the instance of making the best of the virtues of FPGA. This design introduces the data communication between PC and synchro controller by PC Bus, which can carry the synchronous signals parameters to RAM of synchro controller, then according to the theory that the result of comparing counter value with signals parameters is the needed wave, we produce all waves HF ground wave radar needs, moreover all waves are produced time-sharing in order to save resources. 展开更多
关键词 data communication systems Field programmable gate arrays Programmable logic controllers SYNCHRONIZATION
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Combination of terrestrial reference frames based on space geodetic techniques in SHAO:methodology and main issues 被引量:2
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作者 Bing He Xiao-Ya Wang +1 位作者 Xiao-Gong Hu Qun-He Zhao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第9期1-14,共14页
Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material reali... Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material realization of the ITRS defined in IERS Conventions. The main input includes the time series of weekly solutions (or fortnightly for SLR 1983-1993) of observational data for satellite techniques and session-wise normal equations for VLBI. The set of estimated unknowns includes 3- dimensional Cartesian coordinates at the reference epoch 2005.0 of the stations distributed globally and their rates as well as the time series of consistent Earth Orientation Parameters (EOPs) at the same epochs as the input. Besides the final solution, namely SOL-2, generated by using all the inputs before 2015.0 obtained from short-term observation processing, another reference solution, namely SOL- 1, was also computed by using the input before 2009.0 based on the same combination of procedures for the purpose of comparison with ITRF2008 and DTRF2008 and for evaluating the effect of the latest six more years of data on the combined results. The estimated accuracy of the x-component and y-component of the SOL- 1 TRF-origin was better than 0.1 mm at epoch 2005.0 and better than 0.3 mm yr- 1 in time evolution, either compared with ITRF2008 or DTRF2008. However, the z-component of the translation parameters from SOL-1 to ITRF2008 and DTRF2008 were 3.4 mm and -1.0 ram, respectively. It seems that the z-component of the SOL-1 TRF-origin was much closer to the one in DTRF2008 than the one in ITRF2008. The translation parameters from SOL-2 to ITRF2014 were 2.2, -1.8 and 0.9 mm in the x-, y- and z-components respectively with rates smaller than 0.4 mmyr-1. Similarly, the scale factor transformed from SOL-1 to DTRF2008 was much smaller than that to ITRF2008. The scale parameter from SOL-2 to ITRF2014 was -0.31 ppb with a rate lower than 0.01 ppb yr-1. The external precision (WRMS) compared with IERS EOP 08 C04 of the combined EOP series was smaller than 0.06 mas for the polar motions, smaller than 0.01 ms for the UT1-UTC and smaller than 0.02 ms for the LODs. The precision of the EOPs in SOL-2 was slightly higher than that of SOL-1. 展开更多
关键词 astrometry w reference systems -- techniques: interferometers -- methods: data analysis
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Access control technologies for Big Data management systems:literature review and future trends
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作者 Pietro Colombo Elena Ferrari 《Cybersecurity》 2018年第1期338-350,共13页
Data security and privacy issues are magnified by the volume,the variety,and the velocity of Big Data and by the lack,up to now,of a reference data model and related data manipulation languages.In this paper,we focus ... Data security and privacy issues are magnified by the volume,the variety,and the velocity of Big Data and by the lack,up to now,of a reference data model and related data manipulation languages.In this paper,we focus on one of the key data security services,that is,access control,by highlighting the differences with traditional data management systems and describing a set of requirements that any access control solution for Big Data platforms may fulfill.We then describe the state of the art and discuss open research issues. 展开更多
关键词 Big data Access control PRIVACY NoSQL data management systems
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A minimum data set for traumatic brain injuries in Iran
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作者 Maryam Edalatfar Mohsen Sadeghi-Naini +2 位作者 Hamid Reza Khayat Kashani Mitra Movahed Mahdi Sharif-Alhoseini 《Chinese Journal of Traumatology》 CAS CSCD 2022年第5期283-292,共10页
Purpose: Traumatic brain injury (TBI) is one of the major public health concerns worldwide. Developing a TBI registry could facilitate characterizing TBI, monitoring the quality of care, and quantifying the burden of ... Purpose: Traumatic brain injury (TBI) is one of the major public health concerns worldwide. Developing a TBI registry could facilitate characterizing TBI, monitoring the quality of care, and quantifying the burden of TBI by collecting comparable and standardized epidemiological and clinical data. However, a national standard tool for data collection of the TBI registry has not been developed in Iran yet. This study aimed to develop a national minimum data set (MDS) for a hospital-based registry of patients suffering from TBI in Iran. Methods: The MDS was designed in 2 phases, including a literature review and a Delphi study with content validation by an expert panel. After the literature review, a comprehensive list of administrative and clinical items was obtained. Through a two-round e-Delphi approach conducted by invited experts with clinical and research experience in the field of TBI, the final data elements were selected. Results: A MDS of TBI was assigned to 2 parts: administrative part with 5 categories including 52 data elements, and clinical part with 9 categories including 130 data elements. Conclusion: For the first time in Iran, we developed a MDS specified for TBI consisting of 182 data elements. The MDS would facilitate implementing a TBI’s national level registry and providing essential, comparable and standardized information. 展开更多
关键词 Traumatic brain injuries REGISTRIES data systems
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Data Center Power System Stability-Part I: Power Supply Impedance Modeling 被引量:1
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作者 Jian Sun Mingchun Xu +1 位作者 Mauricio Cespedes Mike Kauffman 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2022年第2期403-419,共17页
This two-part paper presents methods to predict,characterize and ensure the stability of data center power systems based on impedance analysis.The work was motivated by recent power system resonance incidents in new d... This two-part paper presents methods to predict,characterize and ensure the stability of data center power systems based on impedance analysis.The work was motivated by recent power system resonance incidents in new data centers.Part I presents new input impedance models for single-phase power supply units(PSUs)to enable this application.Existing impedance models of single-phase PSU cannot meet the requirements of this application because they exclude DC voltage control that affects system stability at low frequency,or are in a dq reference frame that cannot handle the complexity of data center power systems.The developed new models include DC bus dynamics and are directly in the phase domain to simplify system stability analysis,avoiding the need for multiple-input-multiple-output(MIMO)system models and the generalized Nyquist criterion that are difficult to apply but necessary with dq-frame models.Both the converter and system level models also include the coupled current response that is characteristic of AC-DC converters and important for system stability at low frequency.The simple form of the models and system stability analysis directly in the phase domain also make it possible to develop new PSU design methods and performance specifications that together will ensure the stability of new data center power systems.The developed models are validated by laboratory measurements and are used in Part II of the work to study data center power system stability. 展开更多
关键词 data center power systems frequency-domain methods impedance modeling system stability system resonance
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Data Center Power System Stability-Part II: System Modeling and Analysis 被引量:1
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作者 Jian Sun Melaku Mihret +2 位作者 Mauricio Cespedes David Wong Mike Kauffman 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2022年第2期420-438,共19页
This is the second part of a two-part paper on stability study of data center power systems by impedance-based methods.As the basis for this application,Part I[1]developed new impedance models for power supplies that ... This is the second part of a two-part paper on stability study of data center power systems by impedance-based methods.As the basis for this application,Part I[1]developed new impedance models for power supplies that are the most dominant loads in data centers.This second part presents system modeling and analysis methods that can support practical data center power system design to ensure stability.The proposed methods comprise:1)building distribution network modeling by impedance scaling;2)system modeling and model reduction based on equivalent source impedance;3)system stability analysis in the sequence domain to include zero-sequence dynamics;and 4)expansion of system models and analyses to account for network asymmetry and uneven loading.These methods are used to characterize practical resonance problems observed in data centers,explain their root causes,and develop solutions.For systems using Y-connected power supply units(PSUs),the zero sequence is identified as the weakest link and the first to become unstable.The expanded system model and analysis reveal a new,differential-mode instability that is responsible for high frequency resonances.To guarantee system stability,new impedance-based product and system design specifications are developed based on sufficient conditions derived from the Nyquist stability criterion.Laboratory and field measurements are presented to substantiate the proposed methods and conclusions. 展开更多
关键词 data center power systems frequency-domain methods impedance modeling system stability system resonance
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A Partition Checkpoint Strategy Based on Data Segment Priority
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作者 LIANG Ping LIU Yunsheng 《Wuhan University Journal of Natural Sciences》 CAS 2012年第2期109-113,共5页
A partition checkpoint strategy based on data segment priority is presented to meet the timing constraints of the data and the transaction in embedded real-time main memory database systems(ERTMMDBS) as well as to r... A partition checkpoint strategy based on data segment priority is presented to meet the timing constraints of the data and the transaction in embedded real-time main memory database systems(ERTMMDBS) as well as to reduce the number of the transactions missing their deadlines and the recovery time.The partition checkpoint strategy takes into account the characteristics of the data and the transactions associated with it;moreover,it partitions the database according to the data segment priority and sets the corresponding checkpoint frequency to each partition for independent checkpoint operation.The simulation results show that the partition checkpoint strategy decreases the ratio of trans-actions missing their deadlines. 展开更多
关键词 embedded real-time main memory database systems database recovery partition checkpoint data segment priority
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LDPC Decoder for CCSDS Code by Flipping Bits and Fetching Words 被引量:2
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作者 WU Tao LIU Hailiang 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2021年第2期174-182,共9页
The well-known CCSDS(consultative committee for space data systems) LDPC(low density parity check) code for near-earth applications is discussed and used for a case study of Mc Eliece system. First, a data error is pi... The well-known CCSDS(consultative committee for space data systems) LDPC(low density parity check) code for near-earth applications is discussed and used for a case study of Mc Eliece system. First, a data error is picked out with the CCSDS LDPC code. The problem with its generator matrix is illustrated and overcome by a shortened code with some middle code bits deleted. In correspondence, its parity check matrix is also revised with the new quasi-cyclic(QC)-LDPC code. Second, a fast decoding scheme for general QC-LDPC codes is proposed based on flipping bits and fetching words. Besides, a lightweight CCSDS LDPC code based Mc Eliece system can be set up with such codes. The repaired CCSDS LDPC code is supposed to be still useful for communications and storages, and the normalized decoding algorithm is also efficient for general QC-LDPC codes. 展开更多
关键词 LDPC(low density parity check)code CCSDS(consultative committee for space data systems) bit-flipping Mc Eliece system
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200 Mb/s visible optical wireless transmission based on NRZ–OOK modulation of phosphorescent white LED and a pre-emphasis circuit 被引量:7
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作者 李洪磊 陈雄斌 +3 位作者 郭俊清 唐丹颖 黄北举 陈弘达 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第10期16-19,共4页
We present a high-speed visible light communication (VLC) link that uses a commercially available phos- phorescent white light-emitting diode (LED). Such devices have few megahertz bandwidth due to the slow respon... We present a high-speed visible light communication (VLC) link that uses a commercially available phos- phorescent white light-emitting diode (LED). Such devices have few megahertz bandwidth due to the slow response of phosphorescent component, which severely limit the transmission data rate of VLC system. We propose a simple pre-emphasis circuit. With blue-filtering and the pre-emphasis circuit, the bandwidth of VLC system can be enhanced from 3 to 77.6 MHz, which allows non-return-to-zero on-off-keying (NRZ- OOK) data transmission up to 200 Mb/s with the bit error ratio of 5.3 × 10-7 which is below 10-6. The VLC link operates at the room illumination level of -1000 lx at 1.1 m range using a single 1 W white LED. 展开更多
关键词 Bandwidth data communication systems Detector circuits LIGHT Light emission Light transmission Optical communication PHOSPHORESCENCE Wave transmission
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High-speed phosphorescent white LED visible light communications without utilizing a blue filter 被引量:4
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作者 李洪磊 张旖旎 +4 位作者 陈雄斌 吴春晖 郭俊清 高宗余 陈弘达 《Chinese Optics Letters》 SCIE EI CAS CSCD 2015年第8期27-31,共5页
We experimentally demonstrate a high-speed phosphorescent white light emitting diode (LED) visible light communication (VLC) system without utilizing an optical blue filter. Here, the white light response is equal... We experimentally demonstrate a high-speed phosphorescent white light emitting diode (LED) visible light communication (VLC) system without utilizing an optical blue filter. Here, the white light response is equalized by using the proposed analog equalizers. The 3 dB bandwidth of the VLC link could be extended from 3 to 132 MHz, which allows 330 Mbit/s non-return-to-zero on-off keying (NRZ-OOK) data transmission with a bit error ratio (BER) of 7,2 × 10^-10 and 672 Mbit/s 64-quadrature amplitude modulation (64-QAM) data transmission with a BER of 3.2 × 10^-3. These resultant BERs are less than the forward error correction (FEC) limit of 3.8× 10^-3. The VLC link distance is 1 m using a single 1 W LED. The transmitter and receiver modules are integrated to a compact size. Furthermore, the relationships between the signal performance and illumination level or optical power are investigated and analyzed. 展开更多
关键词 Amplitude modulation data communication systems data transfer Detector circuits Error correction Light Light emission Optical communication PHOSPHORESCENCE Visible light communication
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