A computer model to calculate flow resistance in open channels with movable boundaries

A computer package is developed to calculate the flow resistance in an alluvial channel based on the approaches of Einstein,³, Shen,⁶ Simons & Richardson,⁷ and Senturk.⁵ The model can classify the bedform, calculate the flow resistance and design the channel section based on each approach. The results of the different approaches are compared to one set of the field measurements to validate the model. The model can run on main frame computers or personal computers; it will aid hydraulic engineers to choose the optimum channel sections in a fast, efficient and reliable way without human error interpretations.     

Static and Dynamic Characteristics of XPL Programs

One use of performance measurement techniques is in the study of operational characteristics of programs written in high-level programming languages. Information derived from such studies can be used to construct benchmark programs and synthetic workloads,^1,2detect inefficiencies in programming language implementation, and suggest possible improvements in the design of computers.^3,9,10Our main interest is in the latter area: the discovery of primitive operations, implied by the semantics of a programming language, that can be added to the firmware or hardware of a computer to improve overall system performance. These computer architecture optimization techniques have been applied in several studies^3,9and have been used commercially to design efficient pseudo machines for the Burroughs B1700.^10,12     

Rational ℒ1 suboptimal compensators forcontinuous-time systems

The persistent disturbance rejection problem (ℒ¹ optimal control) for continuous time-systems leads to nonrational compensators, even for single input/single output systems. As noted in Dahleh and Pearson (1987), the difficulty of physically implementing these controllers suggests that the most significant application of the continuous time ℒ¹ theory is to furnish achievable performance bounds for rational controllers. In this paper the authors use the theory of positively invariant sets to provide a design procedure, based upon the use of the discrete Euler approximating system, for suboptimal rational ℒ¹ controllers with a guaranteed cost. The main results of the paper show that (i) the ℒ ¹ norm of a continuous-time system is bounded above by the l ¹ norm of an auxiliary discrete-time system obtained by using the transformation z=1+rs and (ii) the proposed rational compensators yield ℒ¹ cost arbitrarily close to the optimum, even in cases where the design procedure proposed in the above mentioned paper fails due to the existence of plant zeros on the stability boundary     

Labolink: An Optically Linked Laboratory Computer Network

Kyoto University has developed a laboratory computer network that demonstrates an easy yet versatile way of accessing several kinds of computers from a single, small-scale computer. Known as "Labolink,"^1,2the network is designed to support laboratory research and education. Unlike the RIG System, another university network reported on recently,³Labolink required no modification of the existing operating system.     

Application of the independent molecule model to elucidate the dynamics of structure I methane hydrate

Raman spectroscopy has exhibited the C–H stretch (A₁ mode) frequency ν₁ of hydrated methanes at 2915 cm⁻¹ for the 5¹² cage and 2905 cm⁻¹ for the 5¹²6² cage. These values are lower than the frequency of 2916.5 cm⁻¹ in gaseous methane. In this paper, we theoretically examine the Raman spectra observed in methane hydrate by normal mode analysis using the independent molecule model. By a breakdown of the symmetry, the four frequencies in modes A₁, E, T₂ and T₂ observed in gaseous methane are separated into nine frequencies in the hydrate. It is necessary to consider the anharmonic potential energy within methane and hydrogen bonding between methane hydrogen and water oxygen in order to get a result in qualitative agreement with experiment. The frequency in the 5¹²6² cage is shifted downward in comparison to the one in 5¹², and the frequencies in the both cages are also shifted downward compared with the frequencies in gas. Calculations are also reported for the isotopic methane (CD₄, ¹³CH₄) hydrates.     

A strain-rate-dependent concrete material model for ADINA

The analysis, design and/or evaluation of protective structures and facilities for military use demands the accurate determination of material and structural response to high-intensity, short-duration impulse loadings. There currently exists a preponderance of data supporting increased strength characteristics in concrete, the primary construction material for protective facilities, at high strain rates. This paper summarizes the modification of the nonlinear concrete material model currently employed in the ADINA finite-element computer programs to account for high strain rate effects. The resultant strain-rate-dependent concrete material model encompasses the strain-rate range from 10⁻⁷s⁻¹ (quasi-static) to 10³s⁻¹, in both compression and tension.     

The economic and health effects on introducing a safe manual handling code of practice

To reduce the incidence of injuries caused by manual handling it was proposed, by a Government Authority, to introduce a Code of Practice. Many industries objected to the introduction of a Code as such codes may have adverse effects on the economics of the industries involved. This paper presents and discusses the methodology used to investigate such effects in those industries in which 80% of reported back injuries occur. Methods were developed to estimate the net costs to industry to comply with the code and the potential effectiveness of the code in preventing injuries.

A survey method was developed which sampled 56% of the Australian work force (about 3.85 × 10⁶ people). Due to the difficulty of specifying, in quantitative terms, the causation of back injury due to manual handling, the scope of the survey method was limited to identifying those work stations where lifting more than 16 kg occurred. There was no modification of potential hazards by specifying other components of back injury causation.

The results indicated that, in Australia, the cost to implement the code would have been $831 × 10⁶ (Australian dollars, 1987) with a recurrent annual cost of $245 × 10⁶. Seventy-five percent of the capital cost and 58% of the recurrent annual cost (excluding the hospital sector) would be required to comply with the Code for lifting weights above 34 kg.

It is estimated that the code would be 27% effective in back injury prevention. The cost to industry for back injuries was $576 × 10⁶ per annum (1984/5 injuries in $A1987) and the projected savings $156 × 10⁶ per annum so the net annual recurrent cost would be reduced from $245 × 10⁶ to $89 × 10⁶.     

An engineering economy expression analyzer

Students and practitioners of engineering economy are faced with the unenviable task of evaluating engineering economy expressions. If the example expression: 1000 ^* (P/F,10,5) − 500 ^* (P/F,6,20) + 100 ^* (P/A,8,20) were solved manually, it would require three table look-ups to determine the values of the cash flow factors.

This paper discusses the automation of engineering economy expression analysis. A public domain program has been developed that solves engineering economy expressions. The above expression can be entered into the program exactly as written, and the computer will respond with the evaluated result. The program also has an integral editor and the ability to solve for unknowns such as interest rates.     

C6H6和SO3相互作用的理论研究（英文）

采用B3LYP和MP2方法在6-31G*、6-31+G*和6-311+G**基组下对C6H6…SO3复合物体系的4种可能结构进行自由优化,得3种。在考虑基组重叠误差校正基础上,得结合能,并用自然键轨道分析方法讨论其相互作用。结果表明,用B3LYP/6-31G*计算3种复合物的结合能分别为-17.75, -18.33, -18.80 kJ/mol,且C6H6和SO3结合时电子从苯环向SO3转移,形成电荷转移复合物,它们之间的作用包含π-p作用方式。     

Optimal reduced-order solution of the weakly coupled discreteRiccati equation

The optimal solution of the weakly coupled algebraic discrete Riccati equation is obtained in terms of a reduced-order continuous-type algebraic Riccati equation via the use of a bilinear transformation. The proposed method has a rate of convergence of O(ε² ) where ε represents a small coupling parameter. A real-world physical example (a chemical plant model) demonstrates the efficiency of the proposed method. Simulation results obtained using a package for a computer-aided control system are presented. For this specific real-world example, the algorithm perfectly matches the presented theory, since convergence, with an accuracy of 10^-4, is achieved after nine iterations (i.e., 0.68¹⁸=10^-4)     

Spatially referenced methods of processing raster and vector data

The authors consider a general method of constructing addressing and arithmetic systems for two-dimensional image data using the hierarchy of ‘molecular’ tilings based on an original isohedral ‘atomic’ tiling. (Each molecular title at level k is formed from a constant number of tiles at level k−1; this is termed the ‘aperture’ property of the hierarchy.) In addition they present 11 objective criteria (which are of significance in cartographic image processing), by which these hierarchies and tilings may be described and compared.

Of the 11 topologically distinct types of isohedral tiling, three ([3⁶], [4⁴] and [6³]) are composed of regular polygons, and two of these ([3⁶] and[4⁴]) satisfy the condition that all tiles have the same ‘orientation’. In general, although each level in a hierarchy is topologically equivalent, the tiles may differ in shape at different levels and only [6³], [4⁴], [4.8²] and [4.6.12] are capable of giving rise to hierarchies in which the tiles at all levels are the same shape. The possible apertures of hierarchies obeying this condition are n² (for any n > 1)in the cases of [6³] and [4⁴]; n² or 2n² in the case of [4.8²]; and n² or 3n² in the case of [4.6.12].

In contrast the only tiling exhibiting the uniform ‘adjacency’ criterion is[3⁶]. However, hierarchies based on this atomic tiling generate molecular tiles with different shapes at every level. If these disadvantages are accepted, hierarchies based on first-level molecular tiles referred to as the 4-shape, 4′-shape, 7-shape and 9-shape are generated. Of these the 4-shape and the 9-shape appear to satisfy many of the cartographically desirable properties in addition to having an atomic tiling which exhibits uniform adjacency.

In recent years the generalized balanced ternary addressing system has been developed to exploit the image processing power of the 7-shape. The authors have generalized and extended this system as ‘tesseral addressing and arithmetic’, showing how it can be used to render a 4-shape into a spatially correct linear quadtree.     

Nonsymmetric streamlined extrusion dies through computer aided engineering

CAD/CAM procedure on the development of nonsymmetric streamlined die for hot extrusion has been detailed in this paper. The modelling for the selection of the processing variables and the design of die geometry were achieved through the use of an Advanced Die Design System (ADDS^™)¹ by taking into account the material's dynamic behaviour. Complicated sculptured surfaces of the die were constructed using Drafting/Design module of Unigraphics II (UGII)². Cutting simulations and NC coding for the machining of die electrodes were conducted by UGII Manufacturing Operation module. Electrodes for EDM die sinking were machined on a 4-axis CNC milling machine and the die cavity was finally eroded.     

TiNi (shape memory) films silicon for MEMS applications

TiNi shape memory alloy in thin film form is an excellent candidate for MEMS microactuation. Using RF sputter deposition, thin films of TiNi (51.7 at% Ti-48.3 at% Ni) have been formed on silicon substrates and produced shape memory behavior at approximately 60°C. Films were amorphous when deposited and were subsequently annealed at 515°C for 30 min. to crystallize the shape memory microstructure. Excellent adherence was achieved onto silicon, SiO₂ and poly-silicon surfaces. Microfabrication was used to create TiNi diaphragms, which exhibited useful shape memory microactuation and other desirable mechanical properties. The diaphragms recovered greater than 2% strain when heated through the phase transformation temperature, providing a maximum work density of at least 5×10⁶ J/m ³. This work density is higher than that of any other type of microactuation     

面向智慧小镇建设的机房电气管线多目标优化布置方法

常规的管线布置优化方法难以在优化过程中得到全局搜索的最优解,导致安全性能无法得到保障,因此面向智慧小镇建设设计一个新的机房电气管线多目标优化布置方法。设置电气管线约束条件,将电压均值、单位时间内电流量、电气管线损耗恢复能力作为目标函数。优化管线布置全局搜索,使用交叉操作的方式不断得到更优解。建立多目标优化电气管线模型,得到电气管线多目标优化的数学模型。通过实验数据可知,该管线布置方法在算法测试中优于常规的3种算法,且在安全性能的检测中只与标准最优值相差6.22×10⁴,3个常规方法与标准最优值的差距为6.813×10⁴、7.6×10⁴、8.32×10⁴,因此可知该多目标优化的管线布置方法可以得到更优解。     

Curvature analysis and visualization for functions defined on Euclidean spaces or surfaces

Visualization of a scalar-valued function ƒ defined on Euclidean n-space ⁿ is often based on its graph-hypersurface . Particularly for curvature interrogation, it is natural to equip ^n-1 with a so-called isotropic metric and use isotropic measures of the graph instead of Euclidean invariants. The ideas are extended to functions defined on surfaces in ³. We present the central formulae for a curvature analysis of functions defined on surfaces. It is shown how to use them for visualization purposes and as a mathematical basis for the construction of interpolating or approximating functions on surfaces.     

Fabrication of ultrathin p++ silicon microstructuresusing ion implantation and boron etch-stop

This paper discusses the fabrication of submicron p⁺⁺ silicon microstructures for a number of MEMS applications using boron ion implantation, rapid thermal annealing, and boron etch-stop. To form these thin structures, the silicon is implanted with boron at an energy of 40 keV and doses of 5×10¹⁵ cm^-2 and 7×10¹⁵ cm^-2, which produce a peak concentration of more than 10²⁰ cm^-3, sufficient for achieving an effective etch-stop in ethylene diamine pyrocathecol. The thickness of the p⁺⁺ layer varies from 0.2 to 0.3 μm depending on the annealing time and temperature. SUPREM simulation has been used to determine optimum implantation and annealing conditions. A number of microstructures, including thin silicon diaphragms as large as 2 mm on a side and 0.2 μm thick, hot wire anemometers with a temperature coefficient of resistance of ~1600 ppm/°C, and piezoresistive sound detectors, have been fabricated with high reproducibility, uniformity, and yield     

On the sensitivity of camera calibration

The orientation position errors of an object's coordinate frame are determined when the offset of image centre and lens distortion are not included in the calibration process. The orientation and position errors are [(u₀)² + (v₀)²]^0.5/f and [(u²₀+v²₀)T²_z + (u²₀T²_z + v²₀T_y²)]^0.5/f, respectively, where f is the focal length, (u₀, v₀) is the offset of image centre and (T_x T_y T_z) is the position of an object. We also obtain the following conclusions: (a) The offset of image centre has little effect on the determinations of the position and orientation of a coordinate frame; (b) the lens distortion will not dramatically change the position and orientation of a coordinate frame; (c) the scale factor has a great effect on the position of a coordinate frame, and on the accuracy of measurement; (d) the offset of image centre is more sensitive than the lens distortion on the determinations of the position and orientation of a coordinate frame. Finally, some experimental results are given to demonstrate the theoretical analysis given in this paper.     

Alternatives for Data Network Architectures

The increasing use of computer data communications over the past several years has spawned a variety of network architectures to support requirements for distributed processing. Developed by various R&D groups,^1-3by the common carriers,^4-4by minicomputer and mainframe manufacturers,^7,8and by the vendors of traditional communications hardware,^9,10these new architectures represent alternative means to similar ends. This article provides a framework for understanding existing and forthcoming systems, focusing particular attention on the impact of evolving requirements and technologies.     

Embedding of complete binary trees into meshes with row-columnrouting

This paper considers the problem of embedding complete binary trees into meshes using the row-column routing and obtained the following results: a complete binary tree with 2^p-1 nodes can be embedded (1) with link congestion one into a ⁹/₈√(2^p)×⁹/ ₈√(2^p) mesh when p is even and a √( ⁹/₈2^p)×√(⁹/ ₈2^p) mesh when p is odd, and (2) with link congestion two into a √(2^p)×√(2^p) mesh when p is even, and a √(2^p-1)×√(2^p-1) mesh when p is odd