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971.
Risks always exist in construction projects and often cause schedule delay or cost overrun. Risk management is a key issue in project management. The first step of risk management is risk identification. It includes the recognition of potential risk event conditions in the project and the clarification of risk responsibilities. We conducted multiple-case studies using a systematic analytical procedure to identify risks in highway projects in Taiwan, to recognize risk allocation by contract clauses, and to analyze the influence of risk allocation on the contractor’s risk handling strategies. The results show that the owner allocates risks by stipulating specific contract clauses into five kinds of risk allocation conditions. If a risk is more controllable by the contractor, the owner has a greater tendency to allocate the risk to the contractor. Risk allocation determines which kinds of risks the contractor would take and influences the contractor’s risk handling decisions. The analysis furthermore indicates that, if the probability of a certain risk event condition is uncontrollable, then with the increasing possibility of taking the risk, the contractor’s tendency of risk handling changes from actively transferring the risk to passively retaining the risk. In contrast, if a risk is controllable and certainly allocated to the contractor, the contractor tends to take the initiative to reduce the impact caused by the risk event rather than retain the risk. 相似文献
972.
Lee J. Wang Z. Liang B. Black W. Kunets V. P. Mazur Y. Salamo G. J. 《Nanotechnology, IEEE Transactions on》2007,6(1):70-74
The formation of "sidewall nanowires" on shallow patterned mesa strips with a modulation depth of only 35 nm on GaAs (100) was demonstrated using molecular beam epitaxy. While self-assembled GaAs sidewall nanowire formation is observed near mesa strips running along [011], relatively thinner AlAs/GaAs layers are formed on identical mesa strips running along [01-1]. Cross-sectional atomic force microscopy (XAFM) on (011) and (01-1) and AFM on (100) are used to understand the formation of the different morphology of the nanostructures, depending on the direction of the mesas. The data indicates that anisotropic surface diffusion of adatoms, resulting from the characteristic (2times4) GaAs (100) surface reconstruction, is responsible for the sidewall nanowire formation and for the different morphology observed along different directions 相似文献
973.
974.
975.
The self-assembly of various nanostructures is recently attracting a great deal of research attention. In this paper, we demonstrate that a palladium chloride aqueous solution, mixed with a proper ammonia solution, can produce Tetra-amminepalladous chloride (Pd(NH3)4Cl2·H2O) nanowires. These nanowires can spontaneously form the two-dimensional hexagon-oriented Pd(NH3)4Cl2·H2O arrays on mica surfaces. We can control the length and height of these nanowires by adjusting their deposit time on the mica substrate. This method can be potentially used in making sensors or in making templates to wire and position nanodevices. 相似文献
976.
Distributed active storage architectures are designed to offload user-level processing to the peripheral from the host servers.
In this paper, we report preliminary investigation on performance and fault recovery designs, as impacted by emerging storage
interconnect protocols and state-of-the-art storage devices. Empirical results obtained using validated device-level and interconnect
data demonstrate the significance of the said parameters on the overall system performance and reliability. 相似文献
977.
The molten iron allocation problem (MIAP) is to allocate molten iron from blast furnaces to steel-making furnaces. The allocation needs to observe the release times of the molten iron defined by the draining plan of the blast furnaces and the transport time between the iron-making and steel-making stages. Time window constraints for processing the molten iron must be satisfied to avoid freezing. The objective is to find a schedule with minimum total weighted completion time. This objective reflects the practical consideration of improving steel-making efficiency and reducing operation cost caused by the need for reheating. Such a problem can be viewed as a parallel machine scheduling problem with time windows which is known to be NP-hard. In this paper, we first formulate the molten iron allocation problem as an integer programming model and then reformulate it as a set partitioning model by applying the Dantzig–Wolfe decomposition. We solve the problem using a column generation-based branch-and-price algorithm. Since the subproblem of column generation is still NP-hard, we propose a state-space relaxation-based dynamic programming algorithm for the subproblem. Computational experiments demonstrate that the proposed algorithm is capable of solving problems with up to 100 jobs to optimality within a reasonable computation time. 相似文献
978.
从矿区建设、采煤技术、煤炭洗选技术和环保、高效先进的煤矿专用设备与自动化控制系统等几个方面介绍了我国煤炭工业取得科研成果,并对这些优秀成果的特点进行了分析。认为我国煤炭工业的科研成果的技术水平在逐年提高,已进入了世界先进行列。 相似文献
979.
980.