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Angular dependence of aerosol information content in capi/TanSat observation over land: Effect of polarization and synergy with A-train satellites

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REMOTE SENSING OF ENVIRONMENT 2017年 196卷 163-177页

作者： Chen, Xi Wang, Jun Liu, Yi Xu, Xiaoguang Cai, Zhaonan Yang, Dongxu Yan, Chang-Xiang Feng, Liang Chinese Acad Sci Inst Atmospher Phys Key Lab Middle Atmosphere & Global Environm Obser Beijing 100029 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Univ Nebraska Earth & Atmospher Sci 303 Bessey Hall Lincoln NE 68588 USA Univ Iowa Dept Chem & Biochem Engn Ctr Global & Reg Environm Res 4133 Seamans Ctr Iowa City IA 52242 USA Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China Univ Edinburgh Sch Geosci Natl Ctr Earth Observat Edinburgh Midlothian Scotland

Aerosols affect the radiative transfer in the absorption bands of carbon dioxide (CO2), thereby contributing to the uncertainties in the retrieval of CO2 from space. A Cloud and Aerosol Polarimetric Imager (capi) has been designed to fly on the Chinese Carbon Dioxide Observation Satellite (TanSat) and provide aerosol and cloud information to facilitate the measurements of CO2. This study aims to assess the information content about aerosol properties that can be obtained from capi's observations of radiance and polarization. We simulate synthetic capi observations using the UNified Linearized Vector Radiative Transfer Model (UNL-VRTM), from which the degree of freedom for signal (DFS) and a posteriori error for various aerosol parameters are calculated using optimal estimation theory. The simulation considers different combinations of fine and coarse aerosols and includes detailed treatment for both soil and vegetation surfaces. It is found that capi can provide 3 to 4.5 independent pieces of information about aerosol parameters, mainly related to aerosol total volume (or aerosol optical depth), fine mode fraction (fmf(nu)) of aerosol volume, and imaginary part of refractive index for coarse mode aerosols. At directions around back-scattering, aerosol information content is smaller due in part to the large directional surface reflectance. In addition, aerosol DFS also depends on fmf(nu), aerosol optical depth and solar zenith angle, and such dependence is analyzed for various viewing and azimuth angles. Due to weaker scattering of coarse aerosol, the information content of large particle is relatively less. Therefore, as fmf(nu) decreases, DFS remains large for fine aerosol and increases for coarse aerosol. With larger aerosol optical depth (AOD), more aerosol information content can be obtained, but when AOD increases to a threshold ranging from 0.5 to 1.2, aerosol DFS doesn't increase any more. At larger solar zenith angles (SZA), a longer light path affected by a

关键词： capi Aerosol Information content Retrieval error DFS

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capi-Precis: Towards a Compute-Centric Interface for Coherent Shared Memory Accelerators 21

CAPI-Precis: Towards a Compute-Centric Interface for Coheren...

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21st International Conference on Field-Programmable Technology (ICFPT)

作者： Mughrabi, Abdullah T. Byrd, Gregory T. North Carolina State Univ Dept Elect & Comp Engn Raleigh NC 27695 USA

ISBN: (数字)9781665453363

ISBN: (纸本)9781665453363

Emerging shared memory accelerator interfaces promote a tighter coupling between traditional general-purpose processing cores and accelerator units through cache-coherence and shared virtual address space capabilities. However, different interface standards solving similar problems often require custom designs and optimizations depending on the adopted interface. This work introduces capi-Precis, an abstract layer between capi, a cache-coherent interface standard proposed by IBM, and the Accelerator Functional Unit (AFU). capi-Precis provides a Compute-Centric FIFO-based paradigm with the shared memory accelerator interface, hiding capi complexities and latency requirements in an abstract layer focusing on optimized, efficient, and scalable AFUs. Such a layer adapts to other shared memory interfaces, such as CCIX or CXL, with minimal overhead in area and performance while preserving the algorithm logic design.

关键词： capi FPGA cache-coherent accelerators hardware/software co-design

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Binary Choice Health State Valuation and Mode of Administration: Head-to-Head Comparison of Online and capi

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VALUE IN HEALTH 2013年第1期16卷 104-113页

作者： Mulhern, Brendan Longworth, Louise Brazier, John Rowen, Donna Bansback, Nick Devlin, Nancy Tsuchiya, Aki Univ Sheffield Sch Hlth & Related Res Sheffield S1 4DA S Yorkshire England Brunel Univ Hlth Econ Res Grp London England Univ British Columbia Sch Populat & Publ Hlth Vancouver BC V5Z 1M9 Canada Off Hlth Econ London England Univ Sheffield Dept Econ Sheffield S1 4DA S Yorkshire England

Background: Health state valuation exercises can be conducted online, but the quality of data generated is unclear. Objective: To investigate whether responses to binary choice health state valuation questions differ by administration mode: online versus face to face. Methods: Identical surveys including demographic, self-reported health status, and seven types of binary choice valuation questions were administered in online and computer-assisted personal interview (capi) settings. Samples were recruited following procedures employed in typical online or capi studies. Analysis included descriptive comparisons of the distribution of responses across the binary options and probit regression to explain the propensity to choose one option across modes of administration, controlling for background characteristics. Results: Overall, 422 (221 online;201 capi) respondents completed a survey. There were no overall age or sex differences. Online respondents were educated to a higher level than were the capi sample and general population, and employment status differed. capi respondents reported significantly better general health and health/life satisfaction. capi took significantly longer to complete. There was no effect of the mode of administration on responses to the valuation questions, and this was replicated when demographic differences were controlled. Conclusions: The findings suggest that both modes may be equally valid for health state valuation studies using binary choice methods (e.g., discrete choice experiments). There are some differences between the observable characteristics of the samples, and the groups may differ further in terms of unobservable characteristics. When designing health state valuation studies, the advantages and disadvantages of both approaches must be considered.

关键词： capi health state valuation online

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From PAPI to capi -: The case of the British Household Panel Survey

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SOCIAL SCIENCE COMPUTER REVIEW 2000年第4期18卷 397-406页

作者： Banks, R Laurie, H Univ Essex Inst Social & Econ Res Colchester CO4 3SQ Essex England

This article describes the conversion of the British Household Panel Survey (BHPS) to a computer aided personal interviewing (capi) mode of data collection. The BHPS is a panel survey, now in its 10th year of data collection, carried out by the Institute for Social and Economic Research based at the University of Essex. Moving to capi midway in the life of a panel survey presents particular challenges, and the article discusses the implications of the move and details the staged strategy by which it was accomplished within a very tight timescale. The authors show how this approach has provided many of the benefits of a capi mode of data collection while posing little risk to the integrity of the panel sample as a whole, generating, nevertheless, challenges of its own.

关键词： capi PAPI BHPS LIB IN2ITIVE surveys panel longitudinal

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A Hardware/Software Co-Design of K-mer Counting Using a capi-Enabled FPGA 30

A Hardware/Software Co-Design of K-mer Counting Using a CAPI...

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30th International Conference on Field-Programmable Logic and Applications (FPL)

作者： Haghi, Abbas Alvarez, Lluc Polo, Jorda Diamantopoulos, Dionysios Hagleitner, Christoph Moreto, Miquel Barcelona Supercomp Ctr BSC Barcelona Spain Univ Politecn Catalunya UPC Barcelona Spain IBM Res Europe Zurich Switzerland

ISBN: (纸本)9781728199023

Advances in Next Generation Sequencing (NGS) technologies have caused the proliferation of genomic applications to detect DNA mutations and guide personalized medicine. These applications have an enormous computational cost due to the large amount of genomic data they process. Although leveraging FPGAs can improve the processing time of such amount of data, the limited memory capacity of FPGAs often restricts the potential gains. To overcome this limitation, IBM capi (Coherent Accelerator Processor Interface) supported platforms provide FPGAs with direct access to the CPU memory. This paper proposes a hardware/software co-design for k-mer counting, one of the most time-consuming phases of genomic applications. The proposed co-design targets capi-enabled FPGAs and is integrated into SMUFIN, a state-of-the-art reference-free method for finding DNA mutations. Results show that the proposed co-design outperforms the CPU-only design by a factor of 2.14x, it consumes 2.93x less energy, and it requires 1.57x less memory.

关键词： FPGA co-design acceleration capi genomics k-mer k-mer counting

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Remote Page Faults with a capi based FPGA 17

Remote Page Faults with a CAPI based FPGA

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10th ACM International Systems and Storage Conference (Systor)

作者： Nider, Joel Binyamini, Yiftach Rapoport, Mike IBM Res Haifa Haifa Israel IBM Syst Haifa Israel

Post-copy VM or container migration requires that the bulk of the memory is transferred after resuming on the destination node [3]. Transferring memory between nodes over a commodity TCP/IP network incurs too much lat... 详细信息

ISBN: (纸本)9781450350358

关键词： capi FPGA page fault migration post-copy

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Empirical Analysis of Data Acquisition Techniques: PAPI vs. capi 6

Empirical Analysis of Data Acquisition Techniques: PAPI vs. ...

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6th International Conference on Cloud System and Big Data Engineering (Confluence)

作者： Bhatia, Mantek Singh Jaiswal, Arunima Amity Univ Dept Comp Sci & Engn ASET Noida Uttar Pradesh India

ISBN: (纸本)9781467382038

Data acquisition refers to the act of collecting data on a large scale. This paper presents a qualitative and quantitative analysis of two data acquisition techniques, namely, Pen and Paper Interviewing (PAPI) and Computer-Assisted Personal Interviewing (capi). It cites two case studies to clearly define the difference between the two techniques. They have been compared on four factors, namely, cost, time consumed during the whole process, productivity of each interviewer and quality assessment of each techniques (average number of errors occurred per interview). It emphasizes on providing absolute numbers to clearly show the difference between the two techniques.

关键词： PAPI capi Data Acquisition Techniques Data mining Data Analytics

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Exploring the Behavior of Coherent Accelerator Processor Interface (capi) on IBM Power8+Architecture and FlashSystem 900 34th

Exploring the Behavior of Coherent Accelerator Processor Int...

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34th International Conference on High Performance Computing (ISC High Performance)

作者： Velusamy, Kaushik Prathapan, Smriti Halem, Milton Univ Maryland Baltimore Cty Baltimore MD 21228 USA

ISBN: (纸本)9783030343569;9783030343552

The Coherent Accelerator Processor Interface (capi) is a general term for the infrastructure that provides high throughput and low latency path to the flash storage connected to the IBM POWER 8+ System. capi accelerator card is attached coherently as a peer to the Power8+ processor. This removes the overhead and complexity of the IO subsystem and allows the accelerator to operate as part of an application. In this paper, we present the results of experiments on IBM FlashSystem900 (FS900) with capi accelerator card using the "capi-Flash - IBM Data Engine for NoSQL Software" Library. This library provides the application, a direct access to the underlying flash storage through user space APIs, to manage and access the data in flash. This offloads kernel IO driver functionality to dedicated capi FPGA accelerator hardware. We conducted experiments to analyze the performance of FS900 with capi accelerator card, using the Key Value Layer APIs, employing NASA's MODIS Land Surface Reflectance dataset as a large dataset use case. We performed Read and Write operations on datasets of size ranging from 1MB to 3TB by varying the number of threads. We then compared this performance with other heterogeneous storage and memory devices such as NVM, SSD and RAM, without using the capi Accelerator in synchronous and asynchronous file IO modes of operations. The asynchronous mode had the best performance on all the memory devices that we used for this study. In particular, the results indicate that FS900 & capi, together with the metadata cache in RAM, delivers the highest IO/s and OP/s for read operations. This was higher than just using RAM, along with utilizing lesser CPU resources. Among FS900, SSD and NVM, FS900 had the highest write IO/s. Another important observation is that, when the size of the input dataset exceeds the capacity of RAM, and when the data access is non-uniform and sparse, FS900 with capi would be a cost-effective alternative.

关键词： capi Accelerators Heterogeneous storage NVM Flash SSDs

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Improving consumption measurement and other survey data through capi: Evidence from a randomized experiment

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JOURNAL OF DEVELOPMENT ECONOMICS 2012年第1期98卷 19-33页

作者： Caeyers, Bet Chalmers, Neil De Weerdt, Joachim Univ Oxford Oxford OX1 2JD England

This paper reports on a randomized survey experiment among 1840 households, designed to compare pen-and-paper interviewing (PAPI) to computer-assisted personal interviewing (CAM). We find that PAPI data contain a large number of errors, which can be avoided in capi. Error counts are not randomly distributed across the sample, but are correlated with household characteristics, potentially introducing sample bias if dubious observations need to be dropped. We demonstrate a tendency for the spread of total measured consumption to be higher on paper compared to capi, translating into significantly higher measured inequality. Investigating further the nature of PAPI's measurement error for consumption, we fail to reject the hypothesis that it is classical: it attenuates the coefficient on consumption when used as explanatory variable and we find no evidence of bias when consumption is used as dependent variable. Finally, capi and PAPI are compared in terms of interview length, costs and respondents' perceptions. (C) 2011 Elsevier B.V. All rights reserved,

关键词： capi Household surveys Consumption measurement Measurement error

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Household Interview Duration Analysis in capi Survey Management

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FIELD METHODS 2014年第4期26卷 390-405页

作者： Boehme, Marcus Stoehr, Tobias Kiel Inst World Econ D-24105 Kiel Germany

This article provides evidence-based guidance for practical survey work, namely choosing interviewers and their workload. Analyzing a survey of 3,568 households obtained through computer assisted personal interviews (capi), we find that interviewers learn considerably while the survey progresses. Time requirements for fieldwork increase concavely with sample size. This allows using larger samples with a given budget than would be expected in planning such projects with simplistic cost estimates. We find a decrease of interview duration of almost 50%, which translates into a significant increase of the average hourly wage the interviewers receive. These learning effects cease after around 20 interviews. Based on our results, we recommend targeting interviewer training by age and technology-affinity of interviewers for capi surveys.

关键词： household surveys capi learning curves interview duration survey planning

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