• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.389-400
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• 2014

This study finds a way to increase the usability of a subway commuter pass. Usability of the commuter pass on a probabilistic statistical model is calculated when the pass is allowed to used in a different mode(bus). A sunk cost of commuter pass is used to reduce the vehicle travels from public transit. 324 people aged 25 to 35 were surveyed and utilized to build a Nested Logit Model on STRADA 3.5 platform. Main results are as follows. First, commuter passes were issued in various forms. Second, the model turns out to be statistically significant in four explanatory variables (discount rate, inter-usablity between modes, forms of payment and periods). Lastly, the more valid on different modes, the more increased of the rail commuter pass.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1443-1453
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• 2010

We simulated the roughing train of the rod mill of SEAH BESTEEL Inc. using finite element method to inhibit surface cracks initiation on workpiece. We designed 2nd pass (square roll) and applied to this roll in the roughing train of the rod mill. Also, we proposed new pass schedule, which changed roll gap of 3rd and 4th groove by using finite element method. We used shear damage model, which is dependent on shear stress ratio and compared the number of damaged elements on workpiece. A damaged element means surface crack. Consequently, after 2nd pass (square roll) is changed, the error rate decreased by 1.43% when compare to that of the old groove. And the number of damaged elements in the new pass schedule decreased by 37.6%, which is less than present pass schedule.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.443-450
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• 2006

In digital image communication systems, YUV 4:2:0 or YUV 4:2:2 images filtered and subsampled versions of YUV 4:4:4 images are utilized and these images recover their size by an interpolation filter. Low pass filters and interpolation filters in the image communication systems are generally utilized. Thus, to improve the image quality, efficient low pass filters and interpolation filters are still required. In this paper, we propose new and efficient low pass filters and interpolation filters and their design method. The low pass filters and interpolation filters used in the MPEG-2 system were developed independently. We utilize wavelet transforms to jointly design low pass filters and interpolation filters. Simulation results show that the proposed filters are superior to the filters used in MPEG-2 in terms of PSNR. In addition, the length of the proposed interpolation filters is shorter than that of the filters used in the MPEG 2 system.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.424-429
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• 1999

The amplifier properties of single distributed feedback dye laser with 106 ps pulse width and 616 nm wavelength were invested using only one XeCl-excimer laser as pump source. For optimized amplification of DFDL, the three-stage amplifiers were arranged with increasing cross-section and accordingly increasing pump energies. The first AmpI, II stages were dye cell of 5 mm, 10 mm and contained a $6{\times}10^{-4}$ [mol/l](solvent : Methanol) of Rhodamine 610. Double-pass amplification in the AmPII was measured to suppress the ASE by using a diffraction grating. The beam intensity of AmpI, II was saturated with a gain of respectively 10 and 48. The last AmpIII was Bethune cell of 30 mm and contained a $3{\times}10^ {-4}$ [mol/l] (solvent : Ethanol) of Rhodamine 610. In the single-pass and double-pass amplification, the output energy was obtained 168.2 $\mu$J and 471$\mu$J respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.67-76
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• 2007

Although Hi-pass have been operated for alleviating traffic congestion and enhancing mobility in expressways since 2000, there is not any standard for safe operation. For that reason, we investigated about tubular markers, which is a typical facility for safety in Hi-pass. Tubular Markers are installed for separating same or opposite traffic flows spatially, supporting the marks at a place which has not only high possibility of accidents but distinguished carefulness of drivers. In this paper, it is noted two considerings; one is prevention of accident from the speed gap of autos and Hi-pass vehicles; the other is guarantee of necessary distance that Hi-pass vehicles could be changes the lanes for off-ramp. Focusing those considerations, it is proposed not only prefer distance of tubular markers, but also fundamental basic subjects. We anticipate that the results of this study would be useful reference in more safe and efficient tollgate operation of Hi-pass.

• Physical Therapy Korea
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• v.17 no.2
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• pp.33-42
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• 2010

The aim of this study was to investigate correlations of the Trunk Control Test (TCT), Postural Assessment Scale for Stroke (PASS-TC), and Trunk Impairment Scale (TIS) and to compare the TCT, PASS-TC, TIS and its subscales in relation to balance, gait and functional performance ability after stroke. Sixty-two stroke patients attending a rehabilitation program participated in the study. Trunk control was measured with the use of TCT, PASS-TC, TIS balance (Berg Balance scale; BSS), gait ability (10 m walk test), functional performance ability (Tuned Up and Go Test TUG) and the mobility part of the Modified Barthel index (MBI), Fugl Meyer-Upper/Lower Extremity ($FM-U{\cdot}L/E$), The scatter-plot (correlation coefficient) was composed for the total scores of the TCT, PASS-TC, and TIS. The multiple regression analysis was performed to evaluate the impact of trunk control on balance, gait, and functional performance ability. Twenty eight participants (45.2%) and twenty participants (32.3%) obtained the maximum score on the TCT and PASS-TC respectively; no subject reached the maximum score on the Trunk Impairment Scale. There were significant correlations between the TIS and TCT (r=.38, p<.01), PASS-TC (r=.30, p<.05), TCT and PASS-TC (r=.59, p<.01). Stepwise multiple regression analysis showed that the BBS score (${\beta}=.420{\sim}.832$) had slightly more power in predicting trunk control than the $FM-U{\cdot}L/E$. TIS-dynamic sitting balance, TUG and the MBI-mobility part. This study 치early indicates that trunk control is still impaired in stroke patients. Measures of trunk control were significantly related with values of balance, gait and functional performance ability. The results imply that management of trunk rehabilitation after stroke should be emphasized.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.7-13
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• 2014

In this paper, a novel waveguide low pass filter for satellite communication is proposed. The proposed low pass filter is designed to obtain wideband characteristics without the interference of higher order modes, sufficient attenuation in the stop-band and small sized lightweight characteristics by evanescent-mode ridge structure. To improve return loss and rejection loss, rectangular ring is inserting around the ridges in the waveguide. Input and output ports of the low pass filter is designed by using the impedance step structure for the impedance matching of the filter. The proposed waveguide low pass filter is fabricated and then measured as return loss over 19.5 dB, insertion loss less than 1.41 dB at the pass-band of 7.25 ~ 8.4 GHz and rejection loss over 67.2 dB at the stop-band of 12.25 ~ 14.5 GHz.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.33-39
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• 2012

The functional evaluation of constructed permeable pavements was conducted in terms of water permeable performance and noise reduction measurements in Seoul city. The field measurements of noise was based on two methods such as pass-by and novel close proximity(NCPX). The pass-by test and NCPX method are related to noise propagation and tire/pavement interaction noise measurement, respectively. For the water permeable tests, five sections were chosen; furthermore, the measurements were conducted for both of wheel path and non-wheel path area. For the pass-by measurement, three sections were chosen; furthermore, two different locations, which were near measurement point to traffic noise and far measurement point inside park or hosing complex, were selected for each section. Finally, tire/pavement interaction noise measurements were carried out at four locations. The results show that the functional performance of water permeability and noise reduction was well remained within 2 or 3 years after permeable pavement construction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.157-159
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• 2010

Most digital cameras apply a Charge Coupled Device(CCD) Sensor or a Complementary Metal Oxide Semiconductor(COMS) Sensor. And the images captured these sensors include unwanted noises. In this paper, we proposed a method of the Noise Reduction(NR) about noise reduction or recovery in the image. The proposed NR method is related to Bandwidth of the Low Pass Filter(LPF). For improvement of NR, we were changing the filter coefficient of the LPF. The results of simulations with various filter coefficients, [1 2 1] in the LPF and [-1 2 -1] in the High Pass Filter(HPF) have ideal frequency bandwidth and high performance. We proposed a filter coefficient [1 2 1] and [-1 2 -1] in the LPF and the HPF respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1843-1848
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• 2010

The Key exchange protocols are very crucial tools to provide the secure communication in the broadband satellite access network. They should be required to satisfy various requirements such as security, Key confirmation, and Key freshness. In this paper, we propose Two authenticated key exchange protocols Two Pass EKE-E(Encrypted Key Exchange-Efficient) and Two Pass EKE-S(Encrypted Key Exchange-Secure) are introduced. A basic idea of the protocols is that a password can be represented by modular addition N, and the number of possible modular addition N representing the password is $2^N$ The Two Pass EKE-E is secure against the attacks including main-in-the-middle attack and off-line dictionary attack, and the performance is excellent so as beyond to comparison with other authenticated key exchange protocols. The Two Pass EKE-S is a slight modification of the Two Pass EKE-E. The Two Pass EKE-S provides computational in feasibility for learning the password without having performed off line dictionary attack while preserving the performance of the Two Pass EKE-E.