100,193 research outputs found
RACK: RApid Clustering using K-means algorithm
No full textThe k-means algorithm is an extremely popular technique for clustering data. One of the major limitations of the k-means is that the time to cluster a given dataset D is linear in the number of clusters, k. In this paper, we employ height balanced trees to address this issue. Specifically, we make two major contributions, (a) we propose an algorithm, RACK (acronym for RApid Clustering using k-means), which takes time favorably comparable with the fastest known existing techniques, and (b) we prove an expected bound on the quality of clustering achieved using RACK. Our experimental results on large datasets strongly suggest that RACK is competitive with the k-means algorithm in terms of quality of clustering, while taking significantly less time
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Receptor for activated C kinase-1 facilitates protein kinase C-dependent phosphorylation and functional modulation of GABA(A) receptors with the activation of G-protein-coupled receptors
No full textGABA(A) receptors are the principal sites of fast synaptic inhibition in the brain. These receptors are hetero-pentamers that can be assembled from a number of subunit classes: alpha(1-6), beta(1-3), gamma(1-3), delta(1), epsilon, theta, and pi, but the majority of receptor subtypes is believed, however, to be composed of alpha, beta, and gamma2 subunits. A major mechanism for modulating GABA(A) receptor function occurs via the phosphorylation of residues within the intracellular domains of receptor subunits by a range of serine/ threonine and tyrosine kinases. However, how protein kinases are targeted to these receptors to facilitate functional modulation remains unknown. Here we demonstrate that the receptor for activated C kinase (RACK-1) and protein kinase C (PKC) bind to distinct sites on GABA(A) receptor beta subunits. Although RACK-1 is not essential for PKC binding to GABAA receptor beta subunits, it enhances the phosphorylation of serine 409, a residue critical for the phospho-dependent modulation of GABA(A) receptor function in the beta1 subunit by anchored PKC. Furthermore, RACK-1 also enhances GABA(A) receptor functional modulation in neurons by a PKC-dependent signaling pathway with the activation of muscarinic acetylcholine receptors (mAChRs). This PKC-dependent modulation of neuronal GABAA receptors was mirrored by an increase in the phosphorylation of GABA(A) receptor beta subunits with the activation of mAChRs.Our results suggest a central role for RACK-1 in potentiating PKC-dependent phosphorylation and functional modulation of GABA(A) receptors. Therefore, RACK-1 will enhance functional cross talk between GABA(A) receptors and G-protein-coupled receptors and therefore may have profound effects on neuronal excitability
Weld toe stress concentrations in multi-planar stiffened tubular KK joints
No full textThis paper reports a parametric stress analysis of various configurations of
rack plate stiffened multi-planar welded KK joints using the finite element
method. The KK joint finds application in the leg structure of offshore oil and
gas jack-up platforms. The rack plate works as a stiffener which reduces the
stress concentration at the brace/chord intersection. This could be an immense
contribution to the increase in fatigue life of the joint, but other hot spot
sites are introduced into the joint. The rack is also used for raising and
lowering of the jack-up hull which gives the jack-up platform its jacking
capability. Over 120 models using a combination of shell and solid elements have
been built and analysed with ABAQUS. Non-dimensional joint geometric parameters
(beta, gamma and Omega) are employed in the study, with the new parameter Omega
being defined as the ratio of rack thickness to chord diameter. Stress
concentration factors (SCFs) are calculated under applied axial and OPB (out-of-
plane bending) loading. Three critical SCF locations are identified for each
load case, with each location becoming the most critical based on the
combination of the non-dimensional parameters selected for the joint. This is
important as careful design can shift the critical SCIF from an area
inaccessible to NDT to one that can be easily inspected. The SCF values
extracted from the models are used to derive six parametric equations through
multiple regression analysis performed using MINITAB. The equations describe the
SCF at the different locations as a function of the non-dimensional ratios. The
equations not only allow the rapid optimisation of multi-planar joints but also
can be used to quickly identify the location of maximum stress concentration and
hence the likely position of fatigue cracks. This in itself is an invaluable
tool for planning NDT procedures and schedules. (C) 2008 Elsevier Ltd. All
rights reserved
Unentbehrliche Vertreter: Deutsche Diplomaten in Paris 1815 - 1870
No full textRack K. Unentbehrliche Vertreter: Deutsche Diplomaten in Paris 1815 - 1870. Pariser Historische Studien. Vol 109. Berlin: De Gruyter; 2017
Optimal Zone Boundaries for Two-class-based Compact 3D AS/RS
No full textCompact, multi-deep (3D), Automated Storage and Retrieval Systems (AS/RS) are becoming more common, due to new technologies, lower investment costs, time efficiency and compact size. Decision-making research on these systems is still in its infancy. We study a particular compact system with rotating conveyors for the depth movement and a Storage/Retrieval (S/R) machine for the horizontal and vertical movement of unit loads. We determine the optimal storage zone boundaries for such systems with two product classes: high and low turnover, by minimizing the expected Storage/Retrieval (S/R) machine travel time. We propose a mixed-integer nonlinear programming model to determine the zone boundaries. A decomposition algorithm and a one dimensional search scheme are developed to solve the model. The algorithm is complex, but the results are appealing since most of them are in closed-form and easy to apply to optimally layout the 3D AS/RS rack. The results are compared with those under random storage, and show that a significant reduction of the machine travel time can be obtained. Finally, a practical example is studied to demonstrate the use and validate our findings.AS/RS;Class-based storage;Order picking;Storage rack design;Travel time model
Stamp Rack
No full textPatent for a stamp rack. This invention is designed to support ordinary rubber stamps. Illustration included
Air flow management inside data centres
No full textA data centre can be defined as an infrastructure facility that houses file servers, processors and other computer equipment, along with a standby power supply. These servers are kept inside cabinets and those cabinets are called racks. These racks are located close to each other inside a data centre to form rows. These rows are located front to front and back to back to form the aisles. These aisles
could be used to supply the chilled air and also to provide room for operational purposes.
Data centres are now widespread due to the high demand of infrastructure requirements, such as the network to operate Internet services. In this thesis, research is focused on the air cooling method, a popular method of cooling that is
used to cool many data centres. The aim of this thesis is to understand the capabilities and limitations of Computational Fluid Dynamics (CFD) analysis of
cooling air flow in data centres. The data centre components, which are the server blade and rack, have been simulated in order to study the environmental conditions
(temperature, pressure and velocity fields) inside the data centre; as such, CFD analysis has been carried out at server, rack and room levels. The proposed method
of a porous media model has been implemented to simulate servers and racks and has been tested and validated through corresponding experiments. It is shown from the results that the porous media model provides good agreement with experimental data of an actual case at the server level. The server racks have been simulated as a porous media with different permeability values in each direction (x ,y, z). In addition, a 3-dimensional CFD model has been used to explore the performance of three different room level cooling strategies based on the aisle containment (cold
and hot aisle containments) and back door cooler. It is shown that using either cold or hot aisle containment within a data centre provides significant improvement
inside the data centre with respect to temperature distribution and the avoidance of hot spots.
Finally, the power input to the computer room air conditioning (CRAC) unit has been analysed for different cooling configurations when assuming the
Coefficient of Performance (COP) of either direct expansion CRAC unit or a chiller system. Furthermore, the comparison between active and passive back door coolers has been done to evaluate the power consumption in the CRAC unit. It is shown that the supply temperature inside the data centre has a significant effect on the CRAC power input (compressor work) of the DX CRAC unit. With respect to comparison between the active and passive back door coolers, it has been found that the reduction of the CRAC unit load is higher when using the active back door cooler
compared to the passive back door cooler, so the active back door cooler is better than passive back door cooler with respect to reduction of load on CRAC unit
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