Arbitrary Layout Research Articles

Enhancing the User-Friendliness of Macintosh Foreign Character Fonts

The popularity of the Macintosh with users of foreign character fonts is explained to a large extent by the letters WYSIWYG: "What you see is what you get." However, with writing systems as complex as those of India or even as straightforward as those of Armenia and Ancient Greece, seeing on the Macintosh screen what one wants to get has often required the mastery of some highly arbitrary keyboard layouts. This article suggests some ways of enhancing the user-friendliness of many Macintosh fonts with the aid of three commercial programs: MacKeymeleon, FONTastic Plus, and Tempo (and Tempo II).

Prediction of workpiece dynamic motion using an optimized artificial neural network

A machining fixture is an element used to hold the workpiece in the desired position and orientation during machining. The overall machining error in a workpiece is a result of different sources of errors in a workpiece–fixture system. One among them is the motion of the workpiece under the action of cutting forces. Evaluation of this dynamic motion is essential for the determination of the overall machining error. Most commonly, the finite element method is employed to compute the workpiece dynamic motion. During optimization of fixture layout, a large number of layouts are generated and the workpiece dynamic motion must be computed for each of the layouts. In such cases, use of the finite element method is prohibitive because of the long computation time required. Also, the results of the finite element analysis are susceptible to different parameters used in the analysis. Hence, an alternate and efficient methodology is necessary to determine the workpiece displacement for a given fixture layout. This article proposes a method of using an artificial neural network for the prediction of workpiece dynamic motion. Different layouts are obtained using a modular fixture and actual machining is performed on the workpiece. For each layout, the workpiece dynamic motion is computed at select datum points and an artificial neural network is trained with these data. To achieve better prediction capability of the artificial neural network and minimize different forms of errors in training and generalization, critical parameters of the artificial neural network are optimized using a genetic algorithm. Then, this optimized network is employed to predict the workpiece dynamic motion for any arbitrary layout. Results show that the optimized artificial neural network is capable of predicting the workpiece dynamic motion with acceptable accuracy (maximum absolute relative error 9.71%). This method, hence, can serve as an economical means of computing the overall machining error during optimization of fixture layouts.

Determining Electromagnetic Energy Loss Through a Radio-Frequency Transmission Line by Infrared Thermal Imaging

This paper presents a technique for measuring local electromagnetic energy loss through a transmission line by infrared thermal imaging. The technique offers an attractive route to investigate solid-state radio-frequency (RF) structures with different sizes and an arbitrary layout of lines by achieving an electromagnetic energy mapping over a wide frequency range between 300 MHz and 6 GHz. The measurement setup and the microstrip RF transmission line test device are described. An analytical model expressing the dissipated power profile as a function of signal frequency, transmission line features, and impedance mismatch is presented. Electromagnetic loss and temperature increase induced by dissipation are numerically studied. Experimental results are presented and discussed.

Optimal Sparse Matrix Dense Vector Multiplication in the I/O-Model

We study the problem of sparse-matrix dense-vector multiplication (SpMV) in external memory. The task of SpMV is to compute y:=Ax, where A is a sparse N×N matrix and x is a vector. We express sparsity by a parameter k, and for each choice of k consider the class of matrices where the number of nonzero entries is kN, i.e., where the average number of nonzero entries per column is k.We investigate what is the external worst-case complexity, i.e., the best possible upper bound on the number of I/Os, as a function of k, N and the parameters M (memory size) and B (track size) of the I/O-model. We determine this complexity up to a constant factor for all meaningful choices of these parameters, as long as k≤N 1−ε, where ε depends on the problem variant. Our model of computation for the lower bound is a combination of the I/O-models of Aggarwal and Vitter, and of Hong and Kung.We study variants of the problem, differing in the memory layout of A. If A is stored in column major layout, we prove that SpMV has I/O complexity \(\Theta(\min\{\frac{kN}{B}\max\{1,\log_{M/B}\frac{N}{\max\{k,M\}}\},\,kN\})\) for k≤N 1−ε and any constant 0<ε<1. If the algorithm can choose the memory layout, the I/O complexity reduces to \(\Theta ({\min\{\frac{kN}{B}\max\{1,\log_{M/B}\frac{N}{kM}\},kN\}})\) for \(k\leq\sqrt[3]{N}\). In contrast, if the algorithm must be able to handle an arbitrary layout of the matrix, the I/O complexity is \(\Theta ({\min\{\frac{kN}{B}\max\{1,\log_{M/B}\frac{N}{M}\},kN\}})\) for k≤N/2.In the cache oblivious setting we prove that with tall cache assumption M≥B 1+ε, the I/O complexity is \(\mathcal {O}({\frac{kN}{B}\max\{1,\log_{M/B}\frac{N}{\max\{k,M\}}\}})\) for A in column major layout.

Human Timeline: A Spatial‐Kinesthetic Exercise in Biblical History

AbstractThe Human Timeline invites students to physically re‐create biblical history. Each student holds a card that denotes an event randomly selected from the biblical timeline. They then arrange themselves chronologically to learn the correct flow of biblical history. Because of the movement involved and the arbitrary layout of the cards among their classmates, learners engage their spatial‐kinesthetic intelligences through this activity. The exercise proves popular among students who identify themselves as “visual” learners, and ultimately serves the biblical studies classroom by reinforcing biblical history as a necessary framework for understanding the biblical text.

Optimization of Spatiotemporal Apertures in Channel Sounding

In this paper, we investigate the impact of the spatiotemporal aperture of a channel sounding system equipped with antenna arrays at the transmitter and receiver on the accuracy of joint estimation of Doppler frequency and bidirection. The contribution of this paper is threefold. First, we state a spatiotemporal model that can describe parallel as well as switched sounding systems. The proposed model is applicable for arbitrary layouts of the spatial arrays. To simplify the derivations, we investigate the special case of linear spatial arrays. However, the results obtained for linear arrays can be generalized to arbitrary arrays. Secondly, we give the necessary and sufficient conditions for a spatiotemporal array to yield the minimum Cramer-Rao lower bound (CRLB) in the single-path case and Bayesian CRLB in the multipath case. The obtained conditions amount to an orthogonality condition on the spatiotemporal array. Thirdly, we define the Doppler-bidirection ambiguity function and derive the necessary and sufficient conditions for a linear spatiotemporal array to be ambiguous. Based on the ambiguity function, we define the normalized side-lobe level, which we propose to use as a figure of merit in the design of spatiotemporal arrays.

Fault-Tolerant Nanoscale Processors on Semiconductor Nanowire Grids

Nanoscale processor designs pose new challenges not encountered in the world of conventional CMOS designs and manufacturing. Nanoscale devices based on crossed semiconductor nanowires (NWs) have promising characteristics in addition to providing great density advantage over conventional CMOS devices. This density advantage could, however, be easily lost when assembled into nanoscale systems and especially after techniques dealing with high defect rates and manufacturing related layout/doping constraints are incorporated. Most conventional defect/fault-tolerance techniques are not suitable in nanoscale designs because they are designed for very small defect rates and assume arbitrary layouts for required circuits. Reconfigurable approaches face fundamental challenges including a complex interface between the micro and nano components required for programming. In this paper, we present our work on adding fault-tolerance to all components of a processor implemented on a 2-D semiconductor NW fabric called nanoscale application specific integrated circuits (NASICs). We combine and explore structural redundancy, built-in nanoscale error correcting circuitry, and system-level redundancy techniques and adapt the techniques to the NASIC fabric. Faulty signals caused by defects and other error sources are masked on-the-fly at various levels of granularity. Faults can be masked at up to 15% rates, while maintaining a 7 density advantage compared to an equivalent CMOS processor at projected 18-nm technology. Detailed analysis of yield, density, and area tradeoffs is provided for different error sources and fault distributions.

An assessment of several displacement-based theories for the vibration and stability analysis of laminated composite and sandwich beams

Abstract Several displacement-based theories are assessed by analyzing the free vibration and the buckling behaviors of laminated beams with arbitrary layouts as well as soft-core sandwich beams. The equations governing the dynamic response of laminated structures are derived by using Hamilton’s principle. However, equations of equilibrium for buckling problems are given by employing the principle of virtual displacements. Moreover, using Navier’s technique and solving the eigenvalue equations, analytical solutions based on the global–local higher-order theory used in this paper are first presented in present study. At the same time, the effect of the order number of higher-order shear deformation as well as interlaminar continuity of transverse shear stress on the global response of both laminated beams and soft-core sandwiches has been also studied. Numerical results show that by increasing the order number of in-plane and transverse displacement components, the global higher-order theories can reasonably predict the natural frequencies and the critical loads of laminated beams with arbitrary layouts and soft-core sandwich beams whereas these global higher-order theories are still less accurate compared to the global–local higher-order theory and the zig-zag theory used herein.

Thermal stress analysis for laminated plates using actual temperature field

A global–local higher order model considering transverse normal deformation is proposed to predict the thermal response of laminated plates subjected to actual temperature field. The in-plane temperature field is expressed as a harmonic series expansion whereas the nonlinear temperature profile in the thickness direction is determined by solving the heat conduction equation. Validity of the proposed model is verified by comparing results with existing publications. Moreover, influence of the temperature fields along the thickness direction on the thermal behaviors of laminates is also investigated. Numerical results show that present model can reasonably predict thermal response of general laminated plates as well as laminated plates with arbitrary layouts under actual temperature loads. However, higher-order zigzag theory neglecting transverse normal deformation is inadequate for predicting thermal response of laminated plates subjected to actual temperature fields. A merit of the present model is that transverse shear stresses can be evaluated directly from the constitutive equations without stress smoothing.

Decentralized Rate Assignments in a Multi-Sector CDMA Network

As the demand for wireless broadband data services grows, it becomes increasingly important to address the issue of optimal resource allocation. Specifically, such allocation should address not only quality of service (QoS) requirements, but continually changing resource demands. In this paper, we consider a data-only multi-sector wideband CDMA network with arbitrary layout of sectors and base-stations. Optimal reverse-link rate allocation for such a network is examined. Using an optimization framework, we develop the conceptual basis for a distributed algorithm for finding the optimal rate assignments using information available to the mobiles. We then use this to propose practical algorithms at the bases as well as the mobiles. These algorithms provide a proportional fair transmission rate/interference control scheme. Finally, we examine the dynamic behavior of such a distributed algorithm in the presence of realistic physical conditions such as shadowing and mobility

Decentralized Rate Assignments in a Multi-Sector CDMA Network

As the demand for wireless broadband data services grows, it becomes increasingly important to address the issue of optimal resource allocation. Specifically, such allocation should address not only quality of service (QoS) requirements, but continually changing resource demands. In this paper, we consider a data-only multi-sector wideband CDMA network with arbitrary layout of sectors and base-stations. Optimal reverse-link rate allocation for such a network is examined. Using an optimization framework, we develop the conceptual basis for a distributed algorithm for finding the optimal rate assignments using information available to the mobiles. We then use this to propose practical algorithms at the bases as well as the mobiles. These algorithms provide a proportional fair transmission rate/interference control scheme. Finally, we examine the dynamic behavior of such a distributed algorithm in the presence of realistic physical conditions such as shadowing and mobility

Compressed histograms with arbitrary bucket layouts for selectivity estimation

Selectivity estimation is an important step of query optimization in a database management system, and multi-dimensional histogram techniques have proved promising for selectivity estimation. Recent multi-dimensional histogram techniques such as GenHist and STHoles use an arbitrary bucket layout. This layout has the advantage of requiring a smaller number of buckets to model tuple densities than those required by the traditional grid or recursive layouts. However, the arbitrary bucket layout brings an inherent disadvantage of requiring more memory to store each bucket location information. This diminishes the advantage of requiring fewer buckets and, therefore, has an adverse effect on the resulting selectivity estimation accuracy. To our knowledge, however, no existing histogram-based technique with arbitrary layout addresses this issue. In this paper, we introduce the idea of bucket location compression and then demonstrate its effectiveness for improving selectivity estimation accuracy by proposing the STHoles+ technique. STHoles+ extends STHoles by quantizing each coordinate of a bucket relative to the coordinate of the smallest enclosing bucket. This quantization increases the number of histogram buckets that can be stored in the histogram. Our quantization scheme allows STHoles+ to trade precision of histogram bucket locations for storing more buckets. Experimental results show that STHoles+ outperforms STHoles on various data distributions, query distributions, and other factors such as available memory size, quantization resolution, and dimensionality of the data space.

Free vibration of laminated composite and sandwich plates using global–local higher-order theory

In this paper the global–local higher-order theory is used to study the free vibration of laminated composite and sandwich plates. This global–local theory can satisfy the free surface conditions and the geometric and stress continuity conditions at interfaces, and the number of unknowns is independent of the layer numbers of the laminate. Based on the higher-order theory, a refined three-noded triangular element satisfying C 1 weak-continuity conditions is presented. For general laminated composite plates, results obtained from present global–local higher-order theory have been found in good agreement with those obtained from three-dimensional elasticity theories. Moreover, this theory is still suitable for analysis of laminated plates with arbitrary layouts and soft-core sandwich plates whereas numerical results show that the global higher-order and first-order theory overestimate natural frequency for these special structures. This theory cannot only calculate the natural frequencies but can accurately predict the modal stress distributions in the thickness direction without any smooth techniques.

A non-asymptotic model of dynamics of honeycomb lattice-type plates

Lightweight structures, consisted of special composite material systems like sandwich plates, are often used in aerospace or naval engineering. In composite sandwich plates, the intermediate core is usually made of cellular structures, e.g. honeycomb micro-frames, reinforcing static and dynamic properties of these plates. Here, a new non-asymptotic continuum model of honeycomb lattice-type plates is shown and applied to the analysis of dynamic problems. The general formulation of the model for periodic lattice-type plates of an arbitrary lay-out was presented by Cielecka and Jędrysiak [Journal of Theoretical and Applied Mechanics 40 (2002) 23–46]. This model, partly based on the tolerance averaging method developed for periodic composite solids by Woźniak and Wierzbicki [Averaging techniques in thermomechanics of composite solids, Wydawnictwo Politechniki Częstochowskiej, Częstochowa, 2000], takes into account the effect of the length microstructure size on the dynamic plate behaviour. The shown method leads to the model equations describing the above effect for honeycomb lattice-type plates. These equations have the form similar to equations for isotropic cases. The dynamic analysis of such plates exemplifies this effect, which is significant and cannot be neglected. The physical correctness of the obtained results is also discussed.

Polarization effects in immersion lithography

Optical proximity correction (OPC) tools are already equipped with the most advanced models for image formation and are capable of thin-film modeling, vector diffraction modeling, and polarization modeling. Accurate simulation of immersion lithography, even in the context of OPC, does not pose any particular difficulty. We use the optical simulator of a commercial OPC software to study source polarization and its impact in process latitude and in proximity and linearity curves. More than a 10-nm difference in both curves is observed versus source polarization at an immersion numerical aperture (NA)>1, projected to print the 45-nm node. Simulation of large and arbitrary layout snippets confirms these results and demonstrates the feasibility of using advanced models in the context of OPC. Also, dry and water-immersion lithography are compared at the same NA<1 and the main differences in imaging are highlighted. The depth-of-focus (DOF) increase in immersion is confirmed in both the ambient medium and the available DOF in resist. The DOF simulation results correlate closely with recent experimental work from other researchers.

A parameter extraction technique for MM/FEM analysis of multilayered RF passives using TRL calibration

This letter introduces a new efficient S-parameter extraction technique by exploiting through-reflection-line calibration. The technique will facilitate the modeling of multilayered RF passives using the hybrid mode matching and finite element method. With the proposed technique, a passive component is viewed as a series of cascaded transmission line discontinuities along the direction that is perpendicular to the layer surfaces. In order to handle arbitrary layout pattern of conductors, finite element method is used to determine a sufficient number of eigen modes. Two practical numerical examples are given to show the effectiveness and validation of the proposed technique.

Pattern density and deposition profile effects on oxide chemical-mechanical polishing and chip-level modeling

Test masks for characterizing pattern-dependent variation of the remained thickness after chemical-mechanical polishing (CMP) were designed by taking the experimentally obtained interaction distance into consideration. Polishing behaviors were characterized by taking into consideration layout pattern density and pitch variations using these masks. Deposition profile effects were also compared between plasma-enhanced tetra ethyl ortho silicate (PETEOS) and high-density plasma (HDP) oxide. Both the measured post-CMP thickness and the expected oxide pattern density after the consideration of deposition profile effects showed a good correlation with respect to the pitch variation for a constant layout pattern density. Also, the relationship between remained thickness and true layout pattern density was deduced. Chip-level CMP modeling was investigated to obtain the post-CMP thickness distributions across a die from its design layout and a few oxide film and CMP parameters. The experimental CMP results agreed well with the modeling results. The effective dummy filling results were shown to achieve a smaller pattern density variation, which resulted in better post-CMP thickness uniformity. Whether the resulting oxide thickness could be predicted for any location on a die for an arbitrary layout, if the effective pattern density distributions are calculated, was discussed.

Pattern density and pitch effects on chemical-mechanical polishing

Test masks for characterizing pattern dependent variations in the thickness remaining after chemical-mechanical polishing (CMP) were designed taking the experimentally obtained interaction distance into consideration. Polishing behaviors were characterized with layout pattern density and pitch variations using these masks. The deposition profile effects were also compared between PETEOS (Plasma Enhanced Tetra Ethyl Ortho Silicate) and HDP (High Density Plasma) oxide. Both measured post-CMP thickness and the expected oxide pattern density from a consideration of the deposition profile effects showed good correlation with respect to pitch variation for a constant layout pattern density. Also, the relationship between the remaining thickness and true layout pattern density were deduced. Secondly, chip-level CMP modeling was investigated to obtain the post-CMP thickness distributions across a die from its design layout and a few oxide film and CMP parameters. The experimental CMP results agreed well with the modeling results. The effective dummy filling results were shown to achieve a smaller pattern density variation, which resulted in uniformly better post-CMP thickness. Finally, whether the resulting oxide thickness can be predicted for any location on a die for an arbitrary layout if the effective pattern density distributions are calculated is discussed.

Approximating layout problems on random graphs

We show that, with overwhelming probability, several well-known layout problems are approximable within a constant for random graphs drawn from the G(n,p n) model where C/n⩽p n⩽1 for all n big enough and for some properly characterized parameter C>1. In fact, our results establish that, with overwhelming probability, the cost of any arbitrary layout of such a random graph is within a constant of the optimal cost.

First-order hybrid Petri nets: a model for optimization and control

We consider in this paper first-order hybrid Petri nets, a model that consists of continuous places holding fluid, discrete places containing a nonnegative integer number of tokens, and transitions, either discrete or continuous. We set up a linear algebraic formalism to study the first-order continuous behavior of this model and show how its control can be framed as a conflict resolution policy that aims at optimizing a given objective function. The use of linear algebra leads to sensitivity analysis that allows one to study of how changes in the structure of the model influence the optimal behavior. As an example of application, we show how the proposed formalism can be applied to flexible manufacturing systems with arbitrary layout and different classes of products.