A decomposition method for surrogate models of large scale structures

Analysis is computationally the most expensive part of optimization. Surrogate models, which are approximate but faster statistical models, can be used in place of more precise but more computer-intensive methods like finite element method to improve efficiency. Unfortunately, the surrogate models are limited by the number of model parameters. So large-scale problems cannot be fully defined by a single surrogate model. Furthermore, current domain decomposition methods cannot be used with black-box models. This study presents a novel approach to design thin-walled structures using surrogate models that overcome the curse of dimensionality by a special decomposition method. A parametric panel structure is defined as a building block. An interface is developed to maintain compatibility across the blocks. Finally, an iterative algorithm finds the displaced state using only local information. Three test structures are used to show the convergence of the algorithm for static analysis. In these sample cases, number of steps required for convergence of the error did not change with the number of panels. This approach offers many benefits including automatic design creation and optimization, effective usage of stream processors and model reuse.     

Prediction of antilock braking system condition with the vehicle stationary using a model-based approach

An Antilock Braking System (ABS) is one of the most important safety facilities equipped in modern vehicles. A self-test is therefore embedded into its ECU to identify any electronic malfunction. However there is no effective method to predict or check its mechanical conditions routinely to ensure its functionality. Because the ABS system is merely actuated above a particular speed in emergency stops, the current brake test facilities are not adequate for ABS test. Because of the dangers involved it would not be acceptable to use a public road to implement such a practice for fault detection so an alternative means must be sought. To provide a safe and convenient solution this paper proposes a novel method to predict ABS faults whilst the vehicle is stationary. In this situation a model-based approach is applied to predict various faults from the ABS, especially from its hydraulic subsystem. As such, a mathematic model is developed to describe the operating processes of ABS including possible faulty conditions. An autonomous control strategy is also designed to actuate the control module independently without the knowledge of the control algorithms embedded in an ABS control module. This approach is evaluated through a Simulink simulation.     

The female antennules of Paracyclops (Cyclopoida: Cyclopidae): their significance for systematics

The setation patterns of female antennules of some Paracyclops species are analysed with reference to the hypothetical 28-segmented antennule of ancestral copepod proposed by Huys and Boxshall in 1991. Comparison between Paracyclops species has revealed a setation pattern common to all species thus far examined. Several modifications of the female antennules have been identified as apomorphic states and can be used in phylogenetic studies. P. waiariki has 12-segmented antennules and exhibits more plesiomorphic characters than the reduced 8-segmented antennules of other species, such as P. fimbriatus. The results confirm that simple segment numbers are unusable as characters in cladistic analysis. Both P. affinis and P. yeatmani, for example, have 11-segmented antennules but analysis of segmental homologies has revealed that the 11-segmented state is convergent in these two species.     

Spatial and temporal variability of size-fractionated biomass and primary production in the Ross Sea (Antarctica) during austral spring and summer

The results of a study on the spatial and temporal dynamics of size-fractionated biomass and production of phytoplankton in the Ross Sea during the austral spring and summer are reported. The spring cruise took place in the offshore Ross Sea from 14 November to 14 December 1994. Sampling was carried out on a transect of 27 stations distributed from 76.5 to 72.0°S along 175°E, and covered the three main Antarctic environments of the polynya open waters, the marginal ice zone and the pack ice area. Three subsystems were identified. The subsystem of the polynya was characterised by the predominance of the micro- and nano-planktonic fractions, chlorophyll (Chl a) concentrations from 69.6 to 164.7 mg m⁻² and production rates from 0.68 to 1.14 g C m⁻² day⁻¹. The second subsystem, the marginal ice zone, showed a relative increase of the micro-planktonic fraction, high biomass levels (from 99.64 to 220 mg Chl m⁻²) and production rates from 0.99 to 2.7 g C m⁻² day⁻¹. The subsystem of the pack ice area had a phytoplankton community dominated by the pico-planktonic fraction and showed low biomasses (from 19.4 to 37.7 mg Chl m⁻²) and production rates (0.28 to 0.60 g C m⁻² day⁻¹). Selective grazing by krill is considered an important factor in determining the size structure of the phytoplankton communities. The summer study consisted of a time series carried out in inshore waters of Terra Nova Bay from 12 January to 8 February 1990. In a well stabilised water column and with high levels of PAR always available, the primary production rates of a community dominated by micro-plankton varied from 0.52 to 1.2 g C m⁻² day⁻¹ (average 0.84). A high P/B ratio, up to 3, and a remarkably elevated mean phaeopigment (Phaeo)/Chl a ratio of 2.4 indicated an active removal of biomass by grazing, confirmed by the presence of faecal pellets in quantities reaching 6000 m⁻³ in the upper 50 m. The peculiarities of the inshore versus offshore environments in terms of community size structure, production processes and their implications as regards the food web are discussed.     

新型轮对检测仪表

目前,机务段用以测定机车轮对轮箍磨损的检测工具一般都为机械检测工具,例如量规和卡规等等.为了对轮对的滚动面(踏面)作有效而精确的检测,国立乌拉尔交通学院与传感器信息工艺学院的专家们研制出了1种新的仪表.     

Fuel consumption model for bus rapid transit

Transportation planners and policy analysts require, for scenario testing, a detailed fuel consumption model of public transit operating in multimodal corridors. Although much effort has been devoted to the development of detailed methodology for estimating fuel consumption of automobile travel on freeways and arterials, the same is not the case for public transit. This paper presents methodology for the estimation of fuel consumption for bus operation on transitways/busways serving major travel corridors. Bus fuel consumption model is reported for standard and articulated buses. This model was adapted from an existing heavy vehicle fuel use model by incorporating the transitway design and bus operational characteristics.     

电力牵引用线性助推器方案

基于轮轨系统电力牵引的力传递与轮轨接触点的粘着系数有关.差的轨面状态会降低可传递的牵引力.现可用各种不同的助推器来产生附加分力,以补偿损失的牵引力.     

Deep water mass characteristics and interannual variability in the North and Central Aegean Sea

The characteristics and interannual variability of the deep water masses in the North and Central Aegean Sea are being investigated through the data sets of the Hellenic Navy Hydrographic Service (HNHS) and the MEDATLAS 1997 project. In the period between 1987 and 1993, the densest deep water in the Mediterranean has been produced in the Aegean Sea (with σ_θ densities reaching up to 29.6 kg/m³), contributing to what has been called the Eastern Mediterranean Transient. The examination of time series of mean integrated values of θ, S and σ_θ below the depth of 500 dbar reveals the significant deep water density increase after 1987 in all of the deep basins in the area. Data suggest that the density increase of 1987–1988 is mainly attributed to a temperature drop, while in 1993, an even more intense density increase is observed, characterized this time by an abrupt salinity increase. We assume that the increased salinity necessary to produce deep water masses with the observed characteristics was not locally produced but rather advected from the Levantine through the South Aegean. After 1993, no new deep water formation episodes have been observed. A series of Θ–S diagrams derived from HNHS CTD casts covering the period between 1993 and 2000, depict the different characteristics of the deep water masses in the area. As 1993 marks the end of the formation period, observed differences between basins in that year must be attributed to different deep water formation sites. Thereafter, the stagnating deep water in the North and Central Aegean basins has been slowly gaining buoyancy by losing salt and gaining heat. The rate at which this phenomenon takes place varies between different deep basins. It is suggested that these variations are linked to the different volumes of each basin as well as to the general circulation features of the Aegean Sea.