7,141 Hits in 6.5 sec

Multidimensional declustering schemes using Golden Ratio and Kronecker Sequences

Chung-Min Chen, R. Bhatia, R.K. Sinha
2003 IEEE Transactions on Knowledge and Data Engineering  
We propose a new declustering scheme for allocating uniform multidimensional data among parallel disks.  ...  In two dimensions, we prove that whenever M is a Fibonacci number, the average performance of the scheme is within 14 percent of the (generally, unachievable) strictly optimal scheme and its worst-case  ...  ACKNOWLEDGMENTS A complete version of this paper with proofs is available from the authors. A preliminary version appeared in ICDE 2000. Rakesh K. Sinha did this work while at Bell Laboratories.  ... 
doi:10.1109/tkde.2003.1198397 fatcat:yufyf3nvljdgfg5kn2vkokfbfi

A Mathematical Model for the Radially Dependent Impedance of a Rotating Disk Electrode

Madhav Durbha
1999 Journal of the Electrochemical Society  
A mathematical model was developed which accounts for the influence of nonuniform current distribution on the impedance response of a rotating disk electrode.  ...  Significant differences between the one-dimensional and two-dimensional models were seen for fast reaction kinetics where the nonuniform ohmic potential distribution is balanced by a nonuniform concentration  ...  Due importance should be attached to the role of nonuniform current distributions for the assessment of electrochemical impedance data for cases where J and N are large.  ... 
doi:10.1149/1.1391914 fatcat:dm3idt3kdjdy3oharpgva5rkle

Efficient cost models for spatial queries using R-trees

Y. Theodoridis, E. Stefanakis, T. Sellis
2000 IEEE Transactions on Knowledge and Data Engineering  
The proposed formulae need no knowledge of the underlying R-tree structure(s) and are applicable to uniform-like and nonuniform data distributions.  ...  AbstractÐSelection and join queries are fundamental operations in Data Base Management Systems (DBMS).  ...  The formula constitutes the first attempt to model R-tree performance for nonuniform distributions of data (including the uniform distribution as a special case: fd d) superceding the analysis in [13]  ... 
doi:10.1109/69.842247 fatcat:psvpzsuozvewzetn3tebumbidm

Design of UAVs-Based 3D Antenna Arrays for a Maximum Performance in Terms of Directivity and SLL

Jesus Garza, Marco A. Panduro, Alberto Reyna, Gerardo Romero, Carlos del Rio
2016 International Journal of Antennas and Propagation  
Furthermore, a comparison of the performance of 3D nonuniform antenna arrays is provided with respect to the most conventional arrays (circular, planar, linear, and the cubic) for UAVs formation flight  ...  This paper presents a design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and side lobe level (SLL).  ...  However, a nonuniform array distribution provides advantages to the system; that is, the possible errors are individual and their consequences too by limiting the effect of each element to its particular  ... 
doi:10.1155/2016/2621862 fatcat:4pwh5volazdtfofmbaxapad5vm

Investigating simulation-based metrics for characterizing linear iterative reconstruction in digital breast tomosynthesis

Sean D. Rose, Adrian A. Sanchez, Emil Y. Sidky, Xiaochuan Pan
2017 Medical Physics (Lancaster)  
The ROI-HO metric trends are compared with 3D reconstructed images from ACR phantom data acquired with a Hologic Selenia Dimensions DBT system.  ...  Two simulation studies are performed using the aforementioned metrics, varying voxel aspect ratio and regularization strength for two types of Tikhonov regularized least-squares optimization.  ...  ACKNOWLEDGEMENTS The authors would like to thank Hologic for providing the phantom data. This work was supported in part by NIH R01 Grants Nos. CA158446, CA182264, EB018102, and NIH F31 Grant No.  ... 
doi:10.1002/mp.12445 pmid:28901614 fatcat:7mbxojk7fzhs3l6br6nrsxt4me

Nonuniform collimator sensitivity: improved precision for quantitative SPECT

M F Kijewski, S P Müller, S C Moore
1997 Journal of Nuclear Medicine  
with a nonuniform sensitivity profile.  ...  Attenuation of photons degrades both the accuracy and the precision of SPECT images; attenuation correction algorithms correct the bias but cannot improve precision.  ...  Part of this work was presented at the 1992 annual meeting of the Society of Nuclear Medicine.  ... 
pmid:8998170 fatcat:butlzxnmvzgoppcozlg6cx5dlq

Top illuminator design for 2D parallel readout in a 3D multilayer optical data storage system

Wenyi Feng, Edwin P. Walker, Haichuan Zhang, Yi Zhang, Alexander S. Dvornikov, Sadik C. Esener, Shizhuo Yin, Francis T. S. Yu, Hans J. Coufal
2002 Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications VII, and Optical Data Storage  
The performance of the illumination optics has been experimentally evaluated and optimized by aberration compensation and equalization of irradiance distribution on the entire data page.  ...  A uniform optical beam sheet is generated to illuminate the desired data page from the top of the disk, and a depth transfer imaging system is used to collect the fluorescence of the written bits within  ...  The US government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright annotation thereon.  ... 
doi:10.1117/12.454038 fatcat:dh6oz75t2farxbcxac7wzjpwhq

Discussion: "Spline Friction in Multiple Disk Brake and Clutch Packs" (Finkin, E. F., 1968, ASME J. Lubr. Technol., 90, pp. 65–71)

M. L. Haviland, E. D. Davison
1968 Journal of Lubrication Technology  
These expressions permit the following evaluations: p" = 0.67 X 10" 6 kg sec/cm 2 p., = 0.406 X 10" 6 kg sec/cm 2 tp = 33.8 deg C ts = 46.3 cleg C Journal of Lubrication Technology july 1 9 6 8 / 653  ...  The existence of spline friction in a mult iple-disk clutch or brake will mean nonuniform energy dissipation (and therefore a nonuniform temperature distribution) and nonuniform wear.  ...  In the optimal control literature these are called systems with distributed parameters [2] and are difficult to handle.  ... 
doi:10.1115/1.3601682 fatcat:4cfhrgwbjfaj7bpzlj7xxbpdaa

G-SSASC: Simultaneous simulation of system models with bounded hazard rates

Shravan Gaonkar, William H. Sanders
2009 Proceedings of the 2009 Winter Simulation Conference (WSC)  
In this paper, we propose G-SSASC, which expands the domain of system models that can be modeled and evaluated to those non-Markovian models that have distributions with bounded hazard rates.  ...  We also show that we obtain a speed-up of up to an order of magnitude for a case study model that evaluates the reliability of a storage system. 663 978-1-4244-5771-7/09/$26.00 ©2009 IEEE  ...  Quasi birth-death processes with exponential distributions have also been used to approximate general distributions to evaluate systems, particularly queuing systems with general distributions (Li and  ... 
doi:10.1109/wsc.2009.5429702 dblp:conf/wsc/GaonkarS09 fatcat:tdb6bccfjzcknppd6k5sbfxtcu

Reliable and randomized data distribution strategies for large scale storage systems

Alberto Miranda, Sascha Effert, Yangwook Kang, Ethan L. Miller, Andre Brinkmann, Toni Cortes
2011 2011 18th International Conference on High Performance Computing  
Random Slicing keeps a small table with information about previous storage system insert and remove operations, drastically reducing the required amount of randomness while delivering a perfect load distribution  ...  The ever-growing amount of data requires highly scalable storage solutions.  ...  with limited concern for the fairness of the data distribution [23] .  ... 
doi:10.1109/hipc.2011.6152745 dblp:conf/hipc/MirandaEKMBC11 fatcat:ji5cn55wjne7npyfilnsvgaiqm

Frictional Coupling between Sliding and Spinning Motion

Zénó Farkas, Guido Bartels, Tamás Unger, Dietrich E. Wolf
2003 Physical Review Letters  
As a simple test system, a sliding and spinning disk on a horizontal flat surface is considered.  ...  We discuss the impact of this coupling between friction force and torque on the physics of granular materials.  ...  However, in general the pressure distribution over the contact area will be nonuniform.  ... 
doi:10.1103/physrevlett.90.248302 pmid:12857231 fatcat:5yppxdn4bze63g6xl5utoozqc4

An efficient cost model for optimization of nearest neighbor search in low and medium dimensional spaces

Yufei Tao, J. Zhang, Dimitris Papadias, Nikos Mamoulis
2004 IEEE Transactions on Knowledge and Data Engineering  
Further, the proposed equations can be applied on nonuniform data with the aid of histograms.  ...  This paper proposes an alternative method that captures the performance of nearest neighbor queries using approximation.  ...  Dealing with Nonuniform Data The above analysis assumes that the data distribution is uniform. In this section, we extend our results to arbitrary distribution with the aid of histograms.  ... 
doi:10.1109/tkde.2004.48 fatcat:lym2gkpqaba5jlc7riovqmb77y

Study on Stiffness and Conditioning Effects of CMP Pad Based on Physical Die-Level CMP Model

Wei Fan, Duane Boning, Leslie Charns, Hiroyuki Miyauchi, Hiroyuki Tano, Shoei Tsuji
2010 Journal of the Electrochemical Society  
Chemical mechanical planarization ͑CMP͒ pad stiffness and conditioning effects were evaluated based on a physical die-level CMP model, with pad effective modulus and asperity height as parameters.  ...  Polishing experimental data ͑dielectric thickness and step height͒ were fitted by the physical model, enabling the extraction of the pad effective modulus and asperity height model parameters.  ...  Massachusetts Institute of Technology assisted in meeting the publication costs of this article.  ... 
doi:10.1149/1.3369963 fatcat:53k4dm2ydbfbveugcfblwl5du4

A Scheduled Activity Energy Aware Distributed Clustering Algorithm for Wireless Sensor Networks with Nonuniform Node Distribution

Nooshin Nokhanji, Zurina Mohd Hanapi, Shamala Subramaniam, Mohamad Afendee Mohamed
2014 International Journal of Distributed Sensor Networks  
Energy aware distributed clustering (EADC) is one of the cluster-based routing protocols proposed for networks with nonuniform node distribution, which can effectively balance the energy consumption among  ...  However, due to the nonuniform node distribution, there is a redundancy in sensed and transmitted data in dense area. This unnecessary energy consumption is not considered in EADC.  ...  Conflict of Interests The authors declare that there is no conflict of interests regarding the publication of this paper.  ... 
doi:10.1155/2014/218678 fatcat:w5ya3zbdnjejzahsmrsyjqaoz4

A model for the prediction of R-tree performance

Yannis Theodoridis, Timos Sellis
1996 Proceedings of the fifteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems - PODS '96  
The cost model uses knowledge of the dataset only i.e., the proposed formula that estimates the number of disk accesses is a function of data properties, namely, the amount of data and their density in  ...  In this paper we present an analytical model that predicts the performance of R-trees (and its variants) when a range query needs to be answered.  ...  ., uniformity of data centers) produces a model that could be efficient for uniformlike data distributions but hardly applicable to nonuniform distributions of data, which are the rule when dealing with  ... 
doi:10.1145/237661.237705 dblp:conf/pods/TheodoridisS96 fatcat:w4erao4tzrehtmy2xbhil634ym
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