• 전자공학회논문지
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• 제52권12호
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• pp.167-173
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• 2015

본 논문에서는 고해상도(Full-HD)급의 비디오를 처리할 수 있는 고효율 비디오 코딩(HEVC) 표준을 따르는 인코더 IP 설계에 대하여 기술한다. 설계된 IP는 HEVC 메인 프로파일 4.1급에 해당되며, 프레임 레이트는 60 fps 로 실시간 인코딩 가능하다. 하드웨어 및 소프트웨어 IP 설계 전에 C 언어로 전체 참조 모델을 개발하였으며 고속처리를 위한 병렬처리구조와 저 전력을 위한 스킵모드를 제안하였다. 또한 IP 관련 펌웨어 및 드라이버 프로그램을 작성하였다. IP 검증을 위한 플랫폼을 개발하였고 설계된 통합 IP를 FPGA 보드로 구현하여 다양한 영상에 대하여 여러 인코딩 조건에서 기능 및 성능을 검증하였다. HM-13.0대비 동일 PSNR에서 약 35% 정도의 비트율 감소와 저전력 모드에서 약 25% 정도의 전력 소모 감소 효과가 있었다.

• Clinics in Shoulder and Elbow
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• 제9권1호
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• pp.83-88
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• 2006

Purpose: To evaluate the usefulness of arthroscopic decompression and miniopen repair that was related with large and massive sized full thickness rotator cuff tear and assess clinical result. Materials and Methods: Twenthy-nine cases of miniopen repaired full thickness tear of rotator cuffs that arthroscopically decompressed were studied. From October 1998 to December 2004 we have analysed 29 repairs of large and massive sized FTRCT, the average age 44 ($32{\sim}71$) years old, mean follow-up was 34 ($12{\sim}84$) months. We analyzed the results statistically by paired t-test. Results: Postoperative VAS of pain improved average 7.0 to 1.7, UCLA score improved 13.7 to 31.9, ADL improved 11.3 to 25.3 respectively (all, P=0.000). Twenty five cases(82.8%) of the patients showed excellent & good results at the final follow-up. The satisfied rate was 26 cases(89.7%). Conclusions: Arthroscopic decompression and miniopen repair in large and massive sized full thickness rotator cuff tears are effective surgical methods.

• 한국재료학회지
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• 제29권12호
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• pp.818-824
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• 2019

In this study, the direct water quenching technique is applied to validate the applicability of direct water quenching as a cooling method in the hot stamping process of 3.2 mm thick boron steel sheet. Cooling performance of conventional die quenching and direct water quenching is compared. Higher cooling rate is obtained by hot stamping with direct water quenching compared to die quenching. As the flow rate of cooling water increases, the cooling rate increases, and a high cooling rate of 71 ℃/s is achieved under flow rate conditions of 0.8 L/min. Through direct water quenching, the cooling time required for sufficient cooling of the sheet is reduced. Full martensitic microstructure is obtained under flow rate condition of 0.8 L/min. Hardness increases with increasing flow rate. From these results, it is verified that the direct water quenching is applicable to the hot stamping of thick boron steel sheet.

• 설비공학논문집
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• 제9권2호
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• pp.104-111
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• 1997

The freezing phenomenon of saturated water with the supercooled region in a horizontal circular cylinder has been studied experimentally by using the holographic real time interferometry technique. From the experiments, it was found that there were three types of freezing patterns. The first is the annular ice layer growing from the cylinder surface at a high cooling rate; the next is the asymmetric ice layer at a moderate cooling rate; and the last is the instantaneous ice layer growth over the full region at lower cooling rate. As the water was coolde from room temperature to the subfreezing point passing through the density inversion point, the freezing pattern was largely affected by the inversion phenomenon, which had much effected the free convection and was susceptible to influences from the cooling rate. When the cooling rate is high, supercooling energy is released before the water is sufficientry mixed by free convection. On the other hand, when the cooling rate is low, there is much time for the water to be mixed by free convection. This seems to be the reason why the different ice layer growths occur.

• 한국콘텐츠학회논문지
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• 제13권11호
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• pp.979-987
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• 2013

전문대학의 재학생 충원율은 갈수록 문제가 되고 있다. 특히, 중도탈락률의 증가는 전문대학을 심각한 위기로 몰고 있어도 속수무책인 상황이다. 왜냐하면, 중도탈락 가능성이 높은 학생들이 입학한 상태에서는 기존의 어떠한 방법도 중도탈락을 방지하기란 어렵기 때문이다. 따라서 본 연구는 중도탈락을 미연에 방지할 수 있는 새로운 방안을 모색하는데 목적을 두었다. 이를 위해 D대학의 입학전형별 중도탈락 실태를 파악한 후, 그 결과를 입학전형 방법과 절차에 반영함으로써 중도탈락을 개선하는 방법을 제시하였다. 또한, 입학전형별로 대학생활 만족도와 중도 탈락률 간 비교를 통해 중도탈락률을 개선하는 방법도 제시하였다. 본 연구에서 제안한 방법은 전문대학의 중도탈락률을 개선하는데 유효하게 적용될 것으로 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.426-445
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• 2012

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1966-1973
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• 2023

Virtual reality technology has been widely used in the field of nuclear and radiation safety, dose rate computing in virtual environment is essential for optimizing radiation protection and planning the work in radioactive-controlled area. Because the CPU-based gamma dose rate computing takes up a large amount of time and computing power for voxelization of volumetric radioactive source, it is inefficient and limited in its applied scope. This study is to develop an efficient gamma dose rate computing code and apply into fast virtual simulation. To improve the computing efficiency of the point kernel algorithm in the reference (Li et al., 2020), we design a GPU-based computing framework for taking full advantage of computing power of virtual engine, propose a novel voxelization algorithm of volumetric radioactive source. According to the framework, we develop the GPPK(GPU-based point kernel gamma dose rate computing) code using GPU programming, to realize the fast dose rate computing in virtual world. The test results show that the GPPK code is play and plug for different scenarios of virtual simulation, has a better performance than CPU-based gamma dose rate computing code, especially on the voxelization of three-dimensional (3D) model. The accuracy of dose rates from the proposed method is in the acceptable range.

• 생물환경조절학회지
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• 제22권3호
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• pp.262-269
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• 2013

본 연구는 임산물 중 수요가 확대되고 있는 곰취 종자의 발아 특성을 구명하고자 실시되었으며, 이를 통하여 효율적인 종자 전처리 및 증식기술을 개발하고자 하였다. 실험은 두 종류로 진행되었는데, 온도(10, 15, 20, $25^{\circ}C$) 및 차광수준(전광, 35, 50, 75, 95%)에 따른 발아력을 조사하였다. 각 실험에 앞서 종자는 전처리를 받았는데, 온도실험에서는 0, 15, 30, 45 및 60일의 저온습윤 처리를, 차광수준 실험에서는 2일 동안 상온건조, 저온건조 및 수침처리를 실시하였다. 곰취 종자는 전처리에 관계없이 상대적으로 낮은 온도인 $10^{\circ}C$일 때 가장 발아가 잘 되었고, 온도가 높아질수록 발아율은 낮아지는 경향을 보였다. 차광수준 실험에서는 전체 처리 중 75% 차광 내 상온건조 처리에서 발아율이 68.1%로 가장 높았으며, 95% 차광 내 수침처리에서 48.6%로 발아율이 가장 낮은 것으로 조사되었다. 한편, 차광수준 실험에서 95%에서는 발아 후 웃자라는 현상을 보였으며, 전광에서는 고사 피해가 관찰되었다. 따라서 본 실험의 결과를 종합하면, 곰취 종자는 전처리로 15일 정도의 저온습윤 저장을 하여 $10^{\circ}C$ 정도의 낮은 온도(시기)에 파종을 하고, 50~75% 정도의 차광처리를 하였을 때 가장 좋은 발아율 및 초기생장을 보일 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.645-652
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• 2000

A total of 80 piglets ($5.18{\pm}0.61kg$ of BW; 16 d of age) were fed experimental diets to evaluate the effect of extruded full-fat soybean (EFS) on the growth of eatly weaned pigs. Pigs were allotted into five treatments based on body weight, in a completely randomized block design. Each treatment has 4 replicates of 4 animals each. Treatments consisted of diets representing substitutional ratios of EFS for soybean meal. 1) 100:0 (SBM), 2) 75:25 (EFS 25), 3) 50:50 (EFS 50), 4) 25:75 (EFS 75) and 5) 0:100 (EFS 100). During phase I (d 0 to 7), piglets were fed diets containing 3,340 kcal ME, 26% crude protein, 1.85% lysine, 1.0% Ca and 0.9% P. For phase II (d 8 to 21), piglets were fed diets supplying 3,340 kcal ME, 23% crude protein, 1.65% lysine, 0.9% Ca and 0.8% P. Urease activity (pH rise) of EFS (0.18) was three times higher than that of SBM (0.06) indicating that processing conditions were not efficient enough to inactivate urease activity. During the first week postweaning, pigs fed SBM had significantly greater average daily gain (ADG), average daily feed intake (ADFI) and better feed conversion ratio (FCR) compared to pigs fed FFS diets. Linear negative effect on growth rate was found as the inclusion rate of FFS increased. During d 8 - 21 postweaning, piglets fed EFS 50 diet showed the best ADG and FCR despite no significant difference between treatment SBM and EFS 25 have been observed. Overall, piglets fed diets up to 50% FFS inclusion rate exhibited similar weight gain. Only piglets fed EFS 100 diet showed a significantly decreased growth rate. No other significant effect was found in feed intake and feed conversion ratio. At d 7, dry matter digestibility was higher in pigs fed SBM diet than piglets fed EFS 75 diet (p<0.05) and crude protein digestibility was higher in piglets fed SBM diet than piglets fed EFS 50, EFS 75 and EFS 100 (p<0.05). At d 21, no difference other than in phosphorus digestibility was detected. This indicates that piglets at 21 d postweaning are capable of utilizing nutrients from FFS. No treatment effects were detected in blood metabolites. The data suggests that piglets at 16 d of age are not sufficiently mature to use extruded FFS in their diets. Nevertheless, FFS seemed to be able to replace upto 50% of SBM in weaned piglet diet.

• 대한기계학회논문집B
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• 제27권2호
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• pp.243-250
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• 2003

The extinction behavior and the unsteady response of augmented reduced mechanism(ARM) have been investigated by adopting an OPPDIF code and a numerical solver for the flamelet equations. By comparing the performance of the ARM based on Miller and Bowman's mechanism(MB-ARM) with that of the ARM based on GRI-Mech 3.0(GRI-3.0-ARM), it is identified that the MB-ARM is more suitable for the unsteady calculation because it is relatively less stiff than GRI-3.0-ARM during an ignition process. The steady results using the MB-ARM, which is modified to predict reasonably the extinction point of experiment, are in excellent agreement with those from full mechanism. Under the sinusoidal transient disturbances of scalar dissipation rate, the unsteady responses of the flame temperature and species concentrations using a modified MB-ARM show in very close agreement with those from full mechanism. It is presumed that above modified MB-ARM is very suitable for the unsteady simulation of turbulent flames because it gives not only a low computational cost but also a good prediction performance for flame structure, extinction point and unsteady response.