• Journal of KIISE:Databases
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• v.29 no.3
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• pp.180-192
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• 2002

We investigate the effect of the data skew of join attributes on the performance of a pipelined multi-way hash join method, and propose two new harsh join methods in the shared-nothing multiprocessor environment. The first proposed method allocates buckets statically by round-robin fashion, and the second one allocates buckets dynamically via a frequency distribution. Using harsh-based joins, multiple joins can be pipelined to that the early results from a join, before the whole join is completed, are sent to the next join processing without staying in disks. Shared nothing multiprocessor architecture is known to be more scalable to support very large databases. However, this hardware structure is very sensitive to the data skew. Unless the pipelining execution of multiple hash joins includes some dynamic load balancing mechanism, the skew effect can severely deteriorate the system performance. In this parer, we derive an execution model of the pipeline segment and a cost model, and develop a simulator for the study. As shown by our simulation with a wide range of parameters, join selectivities and sizes of relations deteriorate the system performance as the degree of data skew is larger. But the proposed method using a large number of buckets and a tuning technique can offer substantial robustness against a wide range of skew conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.256-268
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• 2007

In this paper, we present a watermarking method for 3-D mesh sequences. The main idea is to transform vertex norm with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle) frequency frames according to watermark bit to be embedded. All vertices are divided into groups, namely bin, using the distribution of coefficients in low frequency frames. As the vertices with the identical connectivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into the wavelet coefficients of vertex norm. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. Through simulations, we show that the proposed is flirty robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5789-5794
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• 2015

Recently, thin and light-weight production technologies are needed in IT industry in accordance with increase of the smart phones and mobile PC products. In order to make light and high rigidity products, engineering plastic and aluminum materials are frequently used in products appearance and frame hat support structure. Especially aluminum extrusion and CNC Brick processes are widely used for high strength and high rigidity technology. But extrusion method has constraints to apply exterior design and CNC Brick process has relatively high production cost and low speed of manufacturing. In this research, a new process method is introduced in order to reduce material cost and to improve manufacturing speed dramatically. Plate forging process means basically that thickening of local wall area thickness after deform exterior shape by deep drawing and bending process. Therefore, it is possible to minimize the waste of material and the manufacturing time. In this study the process of plate forging is designed using finite element program AFDEX-2D and the thickness and the width of initial deformed blank. And it is verified as a sample which is a part of laptop developed through the proposed plate forging method.

• Applied Microscopy
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• v.38 no.3
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• pp.151-157
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• 2008

Trigeminal primary afferents expressing $P2X_3$ or transient receptor potential vanilloid 1 (TRPV1) are involved in the transmission of nociceptive information. In order to characterize $P2X_3$- and TRPV1-immunopositive neurons in the trigeminal ganglion (TG) and trigeminal caudal nucleus (Vc), we performed immunofluorescence experiments using anti-$P2X_3$ and anti-TRPV1 antisera and a morphometric analysis. 77.4% (1,401/1.801) of all the $P2X_3$-postive neurons coexpressed TRPV1 and 51.9% (1,401/2,698) of all the THFV1-immunopositive neurons also costained for $P2X_3$ in the TG. Immunoreactivity for both $P2X_3$ and TRPV1 were present in medium-sized neurons but not in small- and large-sized neurons. $P2X_3$ and/or TRPV1-immunopositive fibers were observed in the primary afferents and their associated axons in the Vc. These fibers and terminals were distributed in the superficial lamina of Vc: $P2X_3$-immunopositive fibers and terminals were distributed in the lamina I and II, expecially in the inner part of lamina II (lamina IIi), whereas TRPV1-immunopositive ones were densely detected in the lamina I and outer part of lamina II (lamina IIo). Immunopositive fibers and terminals for both $P2X_3$ and TRPV1 were observed on the border between lamina IIi and IIo. These results suggest that terminals coexpressing $P2X_3$ and TRPV1 are involved in specific roles in the transmission and processing of orofacial nociceptive information.