This paper presents a bi-level hybrid local search(BHLS)algorithm for the three-dimensional loading problem with balancing constraints(3DLP-B),where several rectangular boxes with even densities but different sizes ar...This paper presents a bi-level hybrid local search(BHLS)algorithm for the three-dimensional loading problem with balancing constraints(3DLP-B),where several rectangular boxes with even densities but different sizes are loaded into a single cubic bin to meet the requirements of the space or capacity utilization and the balance of the center of gravity.The proposed algorithm hybridizes a novel framed-layout procedure in which the concept of the core block and its generation strategy are introduced.Once the block-loading sequence has been determined,we can load one block at a time by the designed construction heuristic.Then,the double-search is introduced;its external search procedure generates a list of compact packing patterns while its internal search procedure is used to search the core-block frames and their best distribution locations.The approach is extensively tested on weakly to strongly heterogeneous benchmark data.The results show that it has better performance in improving space utilization rate and balanced condition of the placement than existed techniques:the overall averages from 79.85%to 86.45%were obtained for the balanced cases and relatively high space-usage rate of 89.44%was achieved for the unbalanced ones.展开更多
A design for an IO block array in a tile-based FPGA is presented. Corresponding with the characteristics of the FPGA, each IO cell is composed of a signal path, local routing pool and configurable input/output buffers...A design for an IO block array in a tile-based FPGA is presented. Corresponding with the characteristics of the FPGA, each IO cell is composed of a signal path, local routing pool and configurable input/output buffers. Shared programmable registers in the signal path can be configured for the function of JTAG, without specific boundary scan registers/latches, saving layout area. The local routing pool increases the flexibility of routing and the routability of the whole FPGA. An auxiliary power supply is adopted to increase the performance of the IO buffers at different configured IO standards. The organization of the IO block array is described in an architecture description file, from which the array layout can be accomplished through use of an automated layout assembly tool. This design strategy facilitates the design of FPGAs with different capacities or architectures in an FPGA family series. The bond-out schemes of the same FPGA chip in different packages are also considered. The layout is based on SMIC 0.13 μm logic 1P8M salicide 1.2/2.5 V CMOS technology. Our performance is comparable with commercial SRAM-based FPGAs which use a similar process.展开更多
The authors conduct a textual research on the internal layout of the wards of Chang'an in the Tang Dynasty and challenge the existing hypotheses and the conjectural model of the ward. Questions are raised from the...The authors conduct a textual research on the internal layout of the wards of Chang'an in the Tang Dynasty and challenge the existing hypotheses and the conjectural model of the ward. Questions are raised from the aspects of spatial cognition, street hierarchy, and the regularity of urban fabric. The significant contrast of block dimensions between eastern and western cities is revealed, by comparing the layout pattern of the urban blocks of Tang Chang'an with that of Kahun of ancient Egypt, Olynthus of ancient Greece, Timgad of ancient Rome, and Mirande of the Middle Ages, as well as Old Herat of Afghanistan. It is concluded that a typical ward of Tang Chang'an had a dual structure of strict super-grid placed over residential quarters in an organic growth pattern. The socio-economic causes of this unique structure are also explored. Finally, the authors make a quantitative comparison between a ward in Tang Chang'an and Heijo-kyo of Japan respectively and illustrate the essential difference on concept and structure between the two models.展开更多
Using physical model and numerical simulation techniques, some technical problems were studied systemati- cally, including layout of power station, measures of sediment and floating debris discharging, types of intake...Using physical model and numerical simulation techniques, some technical problems were studied systemati- cally, including layout of power station, measures of sediment and floating debris discharging, types of intake, embed- ded types of spiral ease, layout of underground powerhouse tunnel group and block reinforcement. It was optimal in technique and economy with the arrangement of powerhouse at the dam-toe of both banks ＋ underground powerhouse in the right bank, as well as the intake with a single and small orifice. The sediment and debris problems could be solved with disperse sediment ejection and floating debris discharging holes. With the adoption of techniques for spiral cases such as heat and pressure preservation, cushion layer and combined embedding, the stable operation of generating units can be guaranteed. The arrangement of tailrace tunnel with sloping ceiling was better than that of tailrace surge tank. The technical requirements related to the embedding type of spiral case were proposed. The reinforcement of huge unfavorable blocks was discussed and the new idea for block reinforcement using anti-sliding piles and normal compressive stress of structural plane was put forward.展开更多
Yangzhou was the largest local city of the Sui-Tang period. It consisted of two parts: Zicheng(literally sub-city, but actually the quarter of government offices) and Luocheng (outer city, or the main body of Yangzhou...Yangzhou was the largest local city of the Sui-Tang period. It consisted of two parts: Zicheng(literally sub-city, but actually the quarter of government offices) and Luocheng (outer city, or the main body of Yangzhou City). The former stood on Shugang Hill to the north of the latter. Originally it was Jiangdu Palace-city built by Sui Emperor Yangdi, and was rebuilt into Zicheng in the Tang period. Being irregular in plan, it had four gates on the four sides respectively and two streets in a crisscross pattern within the city. The latter, Luocheng, was built below Shugang Hill in the full Tang or a little later. Rectangular in plan with the major axis pointing north and south, it had four gates on each of the eastern, western and southern sides and one gate on the northern side. The main streets led to the city gates respectively and formed a checkerboard-shaped layout with blocks arranged in the checks. Although its plan layout was designed in imitation of the block system in Chang'an and Luoyang, Yangzhou as a commercial city was developed on a gradually-progressing model with blocks emerging earlier than city walls, and the layout of Luocheng embodied the planning principle with markets as the center. This might have reflected that the restrict block system of the Tang period had been relaxed or broken through in commercial cities. In the Northern Song period, the open-style street-and-lane layout in the capital of Bianjing, or the prefecture of Kaifeng, manifested the collapse of the old block system. This of the freat significance in the history of Chinese cities, but its source can be traced to Yangzhou City of the Tang period.展开更多
基金Project(16B134)supported by Hunan Provincial Department of Education,China
文摘This paper presents a bi-level hybrid local search(BHLS)algorithm for the three-dimensional loading problem with balancing constraints(3DLP-B),where several rectangular boxes with even densities but different sizes are loaded into a single cubic bin to meet the requirements of the space or capacity utilization and the balance of the center of gravity.The proposed algorithm hybridizes a novel framed-layout procedure in which the concept of the core block and its generation strategy are introduced.Once the block-loading sequence has been determined,we can load one block at a time by the designed construction heuristic.Then,the double-search is introduced;its external search procedure generates a list of compact packing patterns while its internal search procedure is used to search the core-block frames and their best distribution locations.The approach is extensively tested on weakly to strongly heterogeneous benchmark data.The results show that it has better performance in improving space utilization rate and balanced condition of the placement than existed techniques:the overall averages from 79.85%to 86.45%were obtained for the balanced cases and relatively high space-usage rate of 89.44%was achieved for the unbalanced ones.
文摘A design for an IO block array in a tile-based FPGA is presented. Corresponding with the characteristics of the FPGA, each IO cell is composed of a signal path, local routing pool and configurable input/output buffers. Shared programmable registers in the signal path can be configured for the function of JTAG, without specific boundary scan registers/latches, saving layout area. The local routing pool increases the flexibility of routing and the routability of the whole FPGA. An auxiliary power supply is adopted to increase the performance of the IO buffers at different configured IO standards. The organization of the IO block array is described in an architecture description file, from which the array layout can be accomplished through use of an automated layout assembly tool. This design strategy facilitates the design of FPGAs with different capacities or architectures in an FPGA family series. The bond-out schemes of the same FPGA chip in different packages are also considered. The layout is based on SMIC 0.13 μm logic 1P8M salicide 1.2/2.5 V CMOS technology. Our performance is comparable with commercial SRAM-based FPGAs which use a similar process.
基金part of the research project No.50108002 funded by National Natural Science Foundation of China
文摘The authors conduct a textual research on the internal layout of the wards of Chang'an in the Tang Dynasty and challenge the existing hypotheses and the conjectural model of the ward. Questions are raised from the aspects of spatial cognition, street hierarchy, and the regularity of urban fabric. The significant contrast of block dimensions between eastern and western cities is revealed, by comparing the layout pattern of the urban blocks of Tang Chang'an with that of Kahun of ancient Egypt, Olynthus of ancient Greece, Timgad of ancient Rome, and Mirande of the Middle Ages, as well as Old Herat of Afghanistan. It is concluded that a typical ward of Tang Chang'an had a dual structure of strict super-grid placed over residential quarters in an organic growth pattern. The socio-economic causes of this unique structure are also explored. Finally, the authors make a quantitative comparison between a ward in Tang Chang'an and Heijo-kyo of Japan respectively and illustrate the essential difference on concept and structure between the two models.
文摘Using physical model and numerical simulation techniques, some technical problems were studied systemati- cally, including layout of power station, measures of sediment and floating debris discharging, types of intake, embed- ded types of spiral ease, layout of underground powerhouse tunnel group and block reinforcement. It was optimal in technique and economy with the arrangement of powerhouse at the dam-toe of both banks ＋ underground powerhouse in the right bank, as well as the intake with a single and small orifice. The sediment and debris problems could be solved with disperse sediment ejection and floating debris discharging holes. With the adoption of techniques for spiral cases such as heat and pressure preservation, cushion layer and combined embedding, the stable operation of generating units can be guaranteed. The arrangement of tailrace tunnel with sloping ceiling was better than that of tailrace surge tank. The technical requirements related to the embedding type of spiral case were proposed. The reinforcement of huge unfavorable blocks was discussed and the new idea for block reinforcement using anti-sliding piles and normal compressive stress of structural plane was put forward.
文摘Yangzhou was the largest local city of the Sui-Tang period. It consisted of two parts: Zicheng(literally sub-city, but actually the quarter of government offices) and Luocheng (outer city, or the main body of Yangzhou City). The former stood on Shugang Hill to the north of the latter. Originally it was Jiangdu Palace-city built by Sui Emperor Yangdi, and was rebuilt into Zicheng in the Tang period. Being irregular in plan, it had four gates on the four sides respectively and two streets in a crisscross pattern within the city. The latter, Luocheng, was built below Shugang Hill in the full Tang or a little later. Rectangular in plan with the major axis pointing north and south, it had four gates on each of the eastern, western and southern sides and one gate on the northern side. The main streets led to the city gates respectively and formed a checkerboard-shaped layout with blocks arranged in the checks. Although its plan layout was designed in imitation of the block system in Chang'an and Luoyang, Yangzhou as a commercial city was developed on a gradually-progressing model with blocks emerging earlier than city walls, and the layout of Luocheng embodied the planning principle with markets as the center. This might have reflected that the restrict block system of the Tang period had been relaxed or broken through in commercial cities. In the Northern Song period, the open-style street-and-lane layout in the capital of Bianjing, or the prefecture of Kaifeng, manifested the collapse of the old block system. This of the freat significance in the history of Chinese cities, but its source can be traced to Yangzhou City of the Tang period.
