http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
손창환(Changhwan Son),박우열(Wooyeol Park),김형균(HyeongGyun Kim),한경숙(KyungSook Han),표창우(Changwoo Pyo) 한국정보과학회 2014 정보과학회논문지 : 시스템 및 이론 Vol.41 No.2
본 논문은 NIST 통계적 난수 검증 모음에 속하는 임의 편위(偏位, random excursions) 검증프로그램을 CUDA 환경에서 병렬화 하고, 성능 향상을 측정한 결과를 보이고 있다. 문제의 추상적 수준에서는 데이터-병렬성이 존재하나, NIST의 구현에서는 사용되는 희소 행렬 구조가 의존 관계를 유발시켜 활용되지 못한다. 자료 구조 변환을 통해 반복문 수준으로 병렬성을 노출시켜 병렬 스캔과 스캐터 기법적용이 가능하게 하였다. 또한, 전역 메모리 접근을 최적화하여 병렬화된 부분이 추가적인 성능 향상을 보일 수 있게 하였다. 병렬화된 임의 편위 검증은 순차적인 구현과 비교할 때 약 44배의 향상된 실행 성능을 보였다. 이진 난수의 검증 속도가 증가하여 수분 내에 가능하게 되면 대규모 이진 난수 발생 때 임의 성 검증을 동시에 진행할 수 있어 암호 키 보안 향상에 기여할 것으로 예상된다. This paper presents parallelization of the random excursions test, which is one of the NIST’s statistical test suite for random bit sequences, and experimental results of measured speedup. Data-parallel property underlies the random excursions test at abstract level of the problem, but the potential cannot be utilized because of the data dependence imposed by the sparse matrix structure adopted by the NIST’s original program. We have exposed data parallelism by transforming the sparse matrix structure. This makes it possible to apply parallel scan and scatter techniques. The parallelized random excursions test shows performance improved by 44 times over the sequential version. If the speed of randomness test would improve to the order of minutes, we can test random bit sequences on the fly when the sequences are generated on a huge scale. This would contribute to level up security of encryption keys.
손창환(Changhwan Son),박우열(Wooyeol Park),김형균(HyeongGyun Kim),한경숙(KyungSook Han),표창우(Changwoo Pyo) 한국정보과학회 2015 정보과학회 컴퓨팅의 실제 논문지 Vol.21 No.7
NIST통계적 난수 검증 모음에 속한 누적 합(CUSUM) 검증을 CUDA 환경에서 병렬화하였다. 배열 사유화를 적용하여 스칼라 변수에 저장하던 랜덤 워크(random walk) 값을 배열 변수에 저장하여 데이터 의존성을 제거하였다. 자료 구조 변경에 따라 알고리즘 각 단계에 병렬 스캔, 스캐터 및 병렬축약 적용이 가능하게 되었다. 또한 CPU를 사용하여 진행되던 부분을 GPU가 담당하게 하여 두 프로세서 사이의 데이터 이동으로 인해 발생하는 직렬화를 해소하였다. 마지막으로 전역 메모리 접근을 최적화하여 전체적으로 순차적 구현 대비 약 23배에 달하는 성능 향상을 달성하였다. 이 결과는 검증 모음의 실행시간 단축과 더불어 암호 키 보안 향상을 위한 난수 연구에 기여할 것으로 예상된다. We have parallelized the cumulative sum (CUSUM) test of NIST’s statistical random number test suite in a CUDA environment. Storing random walks in an array instead of in scalar variables eliminates data dependence. The change in data structure makes it possible to apply parallel scans, scatters, and reductions at each stage of the test. In addition, serial data exchanges between CPU and GPU are removed by migrating CPU’s tasks to GPU. Finally we have optimized global memory accesses. The overall speedup is 23 times over the sequential version. Our results contribute to improving security of random numbers for cryptographic keys as well as reducing the time for evaluation of randomness.
손창환(Changhwan Son),김진욱(Jinouk Kim) 한국인터넷전자상거래학회 2011 인터넷전자상거래연구 Vol.11 No.3
The purpose of this paper is to design the web contents that is a learning system for the title of Accountant. This system is helpful for improving practical education and for preparing the student to receive a Certificate of Qualification. To receive training in practical business, this system is especially designed as a Case- Based Learning(CBL) system. The cases in the system include questions from previous qualification test managed by the Korean Association of Certified Public Tax Accountants (KACPTA). These cases are converted into visual and/or audio formats with pictures and sounds. This web contents design was investigated for its learning effects by three related expert advisors, such as professors and practical specialists. As a result of investigation, all of advisors agree that the web contents design will have a positive effect on improving practical ability. But, this article is limited, in that a practical investigation of its learning effect was not fulfilled, because this article's emphasis was not on a learning system, but rather on web contents.
Son, Seunghyeok,Kim, Byeongseop,Ryu, Cheolho,Hwang, Inhyuck,Jung, ChangHwan,Shin, Jong-Gye The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1
In the shipbuilding industry, three-dimensional (3D) templates play a key role in the completeness evaluation of shell plates with a large curvature in the shell-plate fabrication process. Currently, the information of 3D templates from a ship computer-aided design system is limited; thus, manufacturers depend on their experience to produce the templates manually. This results in the inaccuracy of templates in addition to increased production time. Therefore, if the pieces of the 3D templates can be produced automatically with accurate information, the lead time of the fabrication process can be reduced. In this study, we define a new type of template piece and develop methods for extending a boundary template and converting manufacturing information into numerical control machine input. In addition, based on the results of the study, we propose a production automation system for 3D template pieces. This system is expected to reduce the lead time of the fabrication process.
Son, Seunghyeok,Kim, Byeongseop,Ryu, Cheolho,Hwang, Inhyuck,Jung, ChangHwan,Shin, Jong-Gye The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-
In the shipbuilding industry, three-dimensional (3D) templates play a key role in the completeness evaluation of shell plates with a large curvature in the shell-plate fabrication process. Currently, the information of 3D templates from a ship computer-aided design system is limited; thus, manufacturers depend on their experience to produce the templates manually. This results in the inaccuracy of templates in addition to increased production time. Therefore, if the pieces of the 3D templates can be produced automatically with accurate information, the lead time of the fabrication process can be reduced. In this study, we define a new type of template piece and develop methods for extending a boundary template and converting manufacturing information into numerical control machine input. In addition, based on the results of the study, we propose a production automation system for 3D template pieces. This system is expected to reduce the lead time of the fabrication process.
Bioinspired Hairy Skin Electronics for Detecting the Direction and Incident Angle of Airflow
Chun, Sungwoo,Son, Wonkyeong,Choi, Changsoon,Min, Hyeongho,Kim, Jiwon,Lee, Heon Joon,Kim, Dongjin,Kim, Changhwan,Koh, Je-sung,Pang, Changhyun American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.14
<P>The human skin has inspired multimodal detection using smart devices or systems in fields including biomedical engineering, robotics, and artificial intelligence. Hairs of a high aspect ratio (AR) connected to follicles, in particular, detect subtle structural displacements by airflow or ultralight touch above the skin. Here, hairy skin electronics assembled with an array of graphene sensors (16 pixels) and artificial microhairs for multimodal detection of tactile stimuli and details of airflows (e.g., intensity, direction, and incident angle) are presented. Composed of percolation networks of graphene nanoplatelet sheets, the sensor array can simultaneously detect pressure, temperature, and vibration, all of which correspond to the sensing range of human tactile perceptions with ultrahigh response time (<0.5 ms, 2 kHz) for restoration. The device covered with microhairs (50 μm diameter and 300 μm height, AR = 6, hexagonal layout, and ∼4400/cm<SUP>2</SUP>) exhibits mapping of electrical signals induced by noncontact airflow and identifying the direction, incident angle, and intensity of wind to the sensor. For potential applications, we implement the hairy electronics to a sailing robot and demonstrate changes in locomotion and speed by detecting the direction and intensity of airflow.</P> [FIG OMISSION]</BR>