스프링연결 블록 모델의 확장에 의한 평면 링크기구의 자동합성법

Thesis(doctors) --서울대학교 대학원 :기계항공공학부,2010.2.Docto

최적화 방법에 의한 이진매니퓰레이터의 역기구학 해석과 부분작업공간 설계

Thesis(master`s)--서울대학교 대학원 :기계항공공학부,2005.Maste

A design of 32-bit RISC microprocessor core

학위논문(석사) - 한국과학기술원 : 전기및전자공학과, 1995.2, [ v, 45 p. ]한국과학기술원 : 전기및전자공학과

VLIW 아키텍쳐에서의 사전 참조 방식의 코드 압축 기법

학위논문(박사) - 한국과학기술원 : 전기및전자공학전공, 2000.2, [ ix, 80 p. ]Reducing code size is crucial in embedded systems as well as in high-performance systems to overcome the communication bottleneck between memory and CPU, especially with VLIW (Very Long Instruction Word) processors that require a high-bandwidth instruction prefetching. This paper presents two new approaches for dictionary-based code compression in VLIW processor-based systems. The first approach uses opcode-isomorphism and operand-isomorphism among instruction words. After instruction words are divided into two groups, one for an opcode group and the other for an operand group, the proposed compression algorithm is applied to each group to obtain maximal code compression. Frequently-used instruction words are extracted from the original code to be mapped into two dictionaries, an it opcode dictionary and an it operand dictionary. According to the SPEC95 benchmarks, the proposed technique has achieved an average code compression ratio of 61.56%, 61.3%, and 57.98% in 4-issue, 8-issue, and 12-issue VLIW architectures, respectively and our scheme provide a good trade-off between code compression ratio and the decoding logic delay. Moreover, opcode-isomorphic or operand-isomorphic instruction words achieve the power reduction by 39.93%, 39.40%, and 44.31% in 4-issue, 8-issue, and 12-issue VLIW architectures, respectively. As the second approach, we propose a code compression method based on the dictionary-based code compression, which uses the mobility of instructions to enhance the code compression ratio compared to the first isomorphism method. In the compilation phase, instructions in a basic block can be rescheduled using their mobility. This rescheduling helps to find more identical or opcode-isomorphic/operand-isomorphic instruction words. To implement this scheme, we have used the two-phase algorithm, making global compaction information and compacting the instructions. This scheme improves the code compression ratio by about 10% compared to that of the pre...한국과학기술원 : 전기및전자공학전공

Impact of Urban Thermal Environment Improvement by Street Trees and Pavement Surface Albedo

Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.N