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CUDA를 이용한 BRDF 프로그램의 병렬화 사례 연구
이혁,백선호,홍혜란,김준성 대한전자공학회 2024 전자공학회논문지 Vol.61 No.3
컴퓨터 하드웨어의 발전으로 병렬 프로그래밍은 많은 관심을 받으며 응용분야를 확대하고 있다. 특히, GPU를 이용한 병렬 프로그래밍은 시스템 구성 비용이나 구현의 난이도 측면에서 진입장벽이 낮아져 대량의 고속 연산이 필요한 분야에서 필수적이 되었다. 하지만 GPU의 하드웨어적 특성을 고려하지 않은 무분별한 병렬화는 엔지니어의 수고를 무의미하게 만들뿐 아니라 하드웨어가 가진 연산능력을 충분히 활용하지도 못한다. 본 논문에서는 BRDF 프로그램을 대상으로 일반적인 엔지니어를 위한 실질적인 병렬화 접근 방식을 보여준다. CUDA를 사용하여 다양한 수준에서 BRDF 프로그램을 병렬화하고, 몇 가지 하드웨어의 지표를 확인하여 구현된 병렬화가 자원을 적절하게 사용하고 있는지를 확인함으로써 프로그램의 특성과 함께 하드웨어의 특성을 반영하는 병렬 프로그래밍을 통해 더 높은 성능을 나타내도록 개선한다. 실제 환경의 데이터를 사용한 실험은 병렬 프로그래밍에 약간의 수고만으로도 효율적인 병렬컴퓨팅이 가능함을 보여준다. 병렬화 접근 방식과 문제의 크기에 따라 속도 향상은 4.93에서 64.10 사이로 나타난다. 본 논문에서 보여주는 병렬화 접근 방식은 병렬 프로그램을 도입하고자 하는 연구자들이나, 이미 도입은 했지만 더 높은 성능을 얻고자 하는 연구자들에게 도움이 될 것이다. With advancements in computer hardware, there is a growing interest in parallel programming and its widening scope of applications. In particular, parallel programming using GPUs has become essential in fields demanding extensive high-speed computations, thanks to lower entry barriers in terms of system configuration cost and implementation complexity. However, careless parallelization that overlooks the specific characteristics of GPU's hardware makes the efforts of engineers meaningless and fails to fully exploit the hardware's potential. In this paper, we present a practical parallelization approach for general engineers with a BRDF estimation algorithm. We use CUDA to parallelize the BRDF algorithm at various levels and scrutinize several hardware metrics to ensure efficient resource utilization. By taking into account both algorithm and hardware characteristics, we can enhance the performance of parallel programming. Experiments conducted with real-world data demonstrate that efficient computing is possible with little effort in parallel programming. The observed speedup ranges from 4.93 to 64.10 depending on the chosen parallelization approach and problem size. The parallelization process presented in this paper will be helpful to researchers who want to adopt parallel programming for the first time as well as those who have already adopted it and aim for higher performance.
이혁,김영통,서광원,김서희,신형철,한건수,김일영,이혜경,Lee, Hyeok,Kim, Young-Tong,Seo, Kwang-Won,Kim, Seo-Hee,Shin, Hyeong-Cheol,Han, Kun-Soo,Kim, Il-Young,Lee, Hye-Kyung 대한영상의학회 1997 대한영상의학회지 Vol.37 No.6
Purpose:To analyse the ultrasonographic findings normal thymus in infants and determine the pathologic findings. Materials and Methods:Forty two infants without a history of chronic disease, tumor or steroid therapy were scanned in the axial planes with a 7.0 MHz sector transducer. Bilaterality, homogeneity, and the types, namely bilobate, quadragular or triangular. The intensities of thymic echogenicity were compared with those of the liver and spleen under the same conditions(time-gain compensation, depth and gain). Results:Bilaterality was seen in 36 cases, homogeneity in 35, homogeneity and bilaterality in 29, inhomogeneity and bilaterality in seven, and homogeneity and unilaterality in six. No case showedinhomogeneity and unilaterality. The shape was bilobate in 23 case, quadrangular in 13 and triangular in six, while the other border was convex in 29 cases and straight in 13. In no case wasechogenicity of the thymus greater than that of the liver or spleen. Transverse diameters were echogenicity of the thymus greater than that of the liver or spleen. Transverse diameters were 21-47mm(mean, 37.0mm;SD, 9.4mm) and depths were 10-37.5mm(mean, 25.8mm;SD, 5.9mm). Conclusion:The usual findings of normal thymus in infants are bilaterality and homogeneity, convex or shaight outer border, and echo intensity less than or equal to that of the liver and spleen. The possibility of thymic pathology is suggested when ultrasonography shows uniaterality, inhomogeneous echogeneity, and echogenicity greater than that of the liver and spleen.
우리나라 조기 위암에 대한 내시경 절제 후 장기적인 임상 결과
이혁,이준행 대한상부위장관ㆍ헬리코박터학회 2016 Korean Journal of Helicobacter Upper Gastrointesti Vol.16 No.1
Endoscopic resection is accepted as the standard treatment for early gastric cancer (EGC) without lymph-node metastasis. The indications for endoscopic submucosal dissection (ESD) have been expanded from the standard indications of endoscopic mu- cosal resection. Recently, clinical data supporting further expansion of ESD have been accumulating. In Korea, recent large scale studies have reported favorable long-term outcomes for EGCs that meet the expanded indications, with 5-year overall survival rates similar to those of EGCs meeting the absolute indication. Additionally, several reports on comparison of long-term outcome after endoscopic resection versus surgical treatment have been published. This review elucidates the feasibility of endoscopic resection for EGC, based on evidence from long-term outcome in Korea. There are still some limitations associated with retrospective analy- ses and subsequent biased analysis of outcome based on the post-treatment diagnostic groups and problematic follow-up loss. (Korean J Helicoba cter Up Gastrointest Res 2016;16:1-5)