• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2751-2761
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• 1994

A numerical investigation on the three-dimensional laminar natural convection heat transfer in the periodically fully developed PCB channel has been performed. When heat generating blocks mounted on the adiabatic wall make a channel with their facing shrouding wall, the flow inside the channel becomes periodically fully developed. A single module in the periodically fully developed region is chosen for computational domain in order to save computer storage and computational time. The periodic boundary condition is applied in the anlaysis. The effects of the parameters such as the Rayleigh number, the number of the modules, and the height of channel are examined to obtain the optimum condition for the enhancement of the cooling effectiveness. The result shows that the cooling effect is improved with increasing Rayleigh number and channel height, and decreasing the number of the module. The result also indicates that increasing the height of the channel and number of the module is recommended for a limited space.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.11-19
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• 1999

Lately, with the development of the fields of computer and photogrammetry, Digital Photogrammetric Systems are widely used for the generation of GIS basemap, the acquisition of topographic information and DEM, the formation of digital orthophoto, three-dimensional viewing and so on. According as the demand for the systems is rapidly increasing, we suggest keenly the necessity of domestic technical development, because all of these systems depend on foreign technology until now. In this study, by using digital photogrammetry method, with Visual C++ language, we have developed Digital Photogrammetric Systems for Windows which is able to get three-dimensional coordinates through interior orientation, exterior orientation, epipolar line, image matching from a pair of aerial photos taken with metric camera. This system consists of not only a module which can revise digital map that is being made at National Geographic Institute as a part of data construction project of National Geographic Information System, but also a module which can view three-dimensional image on the screen monitor by using anaglyph for three-dimensional analysis. The digital photogrammetry modules developed in this study are expected to be used as primary modules for the effective management of the urban as well as main modules in developing professional digital photogrammetric systems.

• Journal of IKEEE
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• v.11 no.4
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• pp.358-363
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• 2007

This paper presents a floating point unit(FPU) with 3 stages for a 3D graphics shader engine. It targeted to accelerate 3D graphics in portable device environments. In order to design a balanced architecture for a shader engine, we analyzed shader assembly instructions and estimated the performance of FPU with the method we propose. The proposed unit handles 4-dimensional data through separated two paths that are lead to general operation module and special function module. The proposed FPU is compiled as a form of the cascade FPU with 3 stages to efficiently handle a matrix operation with relatively low hardware overhead. Except some complex instructions that are executed using macro instructions, all instructions complete an operation in a single instruction cycle at 100MHz frequency. A special function module performs all operations in a single clock cycle using the Newton Raphson method with the look-up table.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.216-222
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• 1996

Since many typical 2.5 Gbps optical transmitter modules use a 50$\Omega$ characteristic impedance, they require relatively high voltage and high power sources compared to the 25$\Omega$ module. However, simple replacement of the 50$\Omega$ internal matching impedance with 25$\Omega$ results in bandwidth reduction and consequent problem of data transmitter module is proposed in order to expand the modulator bandwidth. From the calculated resutls based on accurate 3-dimensional inductance analysis, we have found that the series parasitic inductance is a dominant element limiting the bandwidth and the insertion of a 2.5pF capacitor in parallel to the 20$\Omega$ matching resiter can increase the 3 dB bandwidth about 1.4GHz wider. The time-domain results show the rise time (140 psec) without the compensation is greatly improved to 63 psec with the compensation. This capacitive ocmpensation can be implemented easily and be compatible with common manufacturing process of the optical transmitter module.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.236-246
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• 1996

The deployment process of fully folded airbag is analyzed. The methodology of finite element modeling is presented for flat driver side airbag and 3-dimensional passenger side airbag. 'Initial metric option' is used to model 3-dimensional passenger side airbag before deployment. The deformed shapeds and pressure waveforms inside cushion evaluated from simulation are compared to the test results. The agreements between the simulation and the experiments are satisfactory, and the results of simulation are confirmed to be applied to the design of airbag module.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.97-105
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• 2000

One of the most important steps to determine the blank shape and dimensions in deep drawing process is to calculate the surface area of the product. In general, the surface area of axisymmetric products is calculated by mathematical or graphical methods. However, in the case of non-axisymmetric products, it is difficult to calculate the exact surface area due to errors as separated components. Fortunately, it is possible for elliptical products to recognize the geometry of the product in the long side and short side by drafting in another two layers on AutoCAD software. So, in this study, a surface area calculating system is constructed for a design of blank shape of deep drawing products. This system consists of input geometry recognition module and three dimensional modeling module, respectively. The suitability of this system is verified by applying to a real deep drawing product. The system constructed in this study would be very useful to reduce lead time and cost for determining the blank shape and dimensions.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.345-346
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• 2007

In this paper, we propose a Pyramid VQ(PVQ) to quantize the transform coefficients of TCX module for the music improvement of AMR-WB+ codec. The proposed PVQ is compared to the $RE_8$ Lattice VQ used in the AHR-WB+ standard codec, demonstrating improvement 4% and 5.7%, respectively, in Mean Squared Error(MSE) and 3.3% and 4.7%, respectively, in Perceptual Evaluation of Audio Quality(PEAQ) by 8-dimensional and 16-dimensional Pyramid VQ.

• The Journal of the Korean dental association
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• v.56 no.10
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• pp.538-547
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• 2018

ITK-SNAP (http://www.itksnap.org) and 3D Slicer (CMFreg extension module; www.slicer.org) are open-source softwares which can be used for superimposition of cone-beam CT images. For superimposition, segmentation of bone is done with ITK-SNAP, and then voxel based superimposition of CBCT images can be performed using 3D Slicer. 3D Slicer has various visualization modules which are not provided in common commercial programs. 'Models' module is used to visualize two overlapping three-dimensional images, and this allows various visualizations by changing view mode and color of the model. In addition, differences between two CBCT images can be represented in a color map using 'ShapePopulationViewer' module. This report introduces how to superimpose and visualize CBCT images using ITK-SNAP and 3D Slicer, and the usefulness and limitations of both softwares will be discussed in comparison with commercial softwares.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.249-257
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• 2003

The bio-telemetry technologies, that use the wireless miniaturized telemetry module implanted in the human body and transmits several biomedical signal from inside to outside of the body, have been expected to solve the problem such as the patient's inconvenience and the limit for diagnosis. In the case of transceiver system using the wireless RF transmission method, the method of three-dimensional localization for implantable miniaturized telemetry module is necessary to detect the exact position of disease. A new method for three-dimensional localization using small loop antenna in the implantable miniaturized telemetry module was proposed in this paper. We proposed a method that can accurately determine the position of telemetry module by analyzing the differences in the strength of signal, which is received at each of the small size RF receiver array installed on the body surface.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.1
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• pp.13-22
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• 2001

This paper presents three dimensional structure of RF packages and the improvement effect of its electrical characteristics when implementing RF transceivers. We divided RF modules into several subunits following each subunit function based on the partitioning algorithm which suggests a method of three dimension stacking interconnection, PAA(pad area array) interconnection and stacking of three dimensional RF package structures. 224MHz ITS(Intelligent Transportation System) RF module subdivided into subunits of functional blocks of a receiver(RX), a transmitter(TX), a phase locked loop(PLL) and power(PWR) unit, simultaneously meeting the requirements of impedance characteristic and system stability. Each sub­functional unit has its own frequency region of 224MHz, 21.4MHz, and 450KHz~DC. The signal gain of receiver and transmitter unit showed 18.9㏈, 23.9㏈. PLL and PWR modules also provided stable phase locking, constant voltages which agree with design specifications and maximize their characteristics. The RF module of three dimension stacking structure showed $48cm^3$, 76.9％ reduction in volume and 4.8cm, 28.4％ in net length, 41.8$^{\circ}C$, 37% in maximum operating temperature, respectively. We have found that three dimensional PAA package structure is able to produce high speed, high density, low power characteristics and to improve its functional characteristics by subdividing RF modules according to the subunit function and the operating frequency, and the features of physical volume, electrical characteristics, and thermal conditions compared to two dimensional RF circuit modules.