Input Position Research Articles

Directly phase-modulation-mode-locked doubly-resonant optical parametric oscillator

We present results on direct mode-locking of a doubly-resonant optical parametric oscillator (DRO) using an electro-optic phase modulator with low resonant frequency of 80 MHz as the single mode-locking element. Pumped by a cw laser at 532 nm and based on MgO:sPPLT as the nonlinear material, the DRO generates 533 ps pulses at 80 MHz and 471 ps pulses at 160 MHz. Stable train of mode-locked pulses is obtained at a modulation depth of 1.83 radians when the modulation frequency is precisely tuned and the cavity length is carefully adjusted. The effects of frequency detuning, modulation depth, input laser pump power, crystal temperature and position of modulator inside the cavity, on pulse duration and repetition rate have been studied. Operating at degeneracy, under mode-locked condition, the signal-idler spectrum exhibits a bandwidth of ~31 nm, and the spectrum has been investigated for different phase-matching temperatures. Mode-locked operation has been confirmed by second-harmonic-generation of the DRO output in a β-BaB₂O₄ crystal, where a 4 times enhancement in green power is observed compared to cw operation.

Design of CAN-Bus Control Modules for Passenger Car

The construction scheme of CAN-bus modules on passenger cars is designed in this paper according to the development trend of safety and information intellectualization. The scheme includes functional partition of vehicle, electrical system classification, control unit division, and the assignment of the network ID. In particular, a detail description is given to the position and functions of input and output control modules. Tests have been given by OEMs to prove its practicability and validity.

A vertically intersected dual-axis modularized reconfigurable actuator: design and application for a six-axis humanoid robot arm

A vertically intersected dual-axis modularized actuator system (DAMA) is developed and applied to a six-axis humanoid robot arm in this article. The DAMA consists of a two independent joint system, and the system structure is further refined using finite element analysis. It will be shown that the novel DAMA modular system can be used to easily construct a mechanism with any degrees of freedom. In other words, a modular or reconfigurable system can be achieved using the DAMA module. Based on simulations with ADAMS and MATLAB software packages, the system dynamic properties can be observed. In addition, the hardware and software systems of the DAMA are developed. The hardware architecture is composed of a microprocessor, an RS-232 to CAN bus module, and two independent-joint controller modules. The software control system is written in Visual C++. The system employs a simple but effective PID scheme to independently control the DAMA's two joints. The experimental results show that for an S-curve and circle trajectory input position command, the DAMA and the six-axis humanoid robot arm, which is formed by the DAMA module, can track the command well. Hence, the DAMA can be used as a generic module for multiple-degree-of-freedom systems.

Simulation of Extractive Distillation for Recycling Tetrahydrofuran from Pharmaceutical Wastewater with Chem CAD Software

The functions and application of ChemCAD simulation software was introduced. Mathematical model of extraction distillation process was established. The extractive distillation process for preparation of tetrahydrofuran (THF) was simulated by SCDS rectification model in ChemCAD software, methanol-THF-solution and ethanedol- lithium chloride solution as extractant. Influence of extraction agent on vapor-liquid equilibrium curve of methanol- THF system and effects of theoretical plate number, feed and extractant input positions, extraction agent ratio (m(chlorinated lithium): v(ethanediol)), extractant ratio (m (extractant): m(feed)) and reflux ratio on tower top mass fraction of THF were investigated. The results of simulation were compared with experimental data. Under optimum extraction distillation conditions: theoretical plate 30, extractant plate 6, feed plate 18, extraction agent ratio 0.24g/mL, extractant ratio 2.7 and reflux ratio 5.0, mass fraction of THF on tower top can reach 97.2%. The distribution characteristic parameters of the column were simulated. The results of simulation and experimental data agree satisfactorily.

Sensitivity of Boolean formulas

The sensitivity set of a Boolean function at a particular input is the set of input positions where changing that one bit changes the output. Analogously we define the sensitivity set of a Boolean formula in a conjunctive normal form at a particular truth assignment, it is the set of positions where changing that one bit of the truth assignment changes the evaluation of at least one of the conjunct in the formula. We consider Boolean formulas in a generalized conjunctive normal form. Given a set ℱ of Boolean functions, an ℱ-constraint is an application of a function from ℱ to a tuple of literals built upon distinct variables, an ℱ-formula is then a conjunction of ℱ-constraints. In this framework, given a truth assignment I and a set of positions S, we are able to enumerate all ℱ-formulas that are satisfied by I and that have S as the sensitivity set at I. We prove that this number depends on the cardinality of S only, and can be expressed according to the sensitivity of the Boolean functions in ℱ.

Nonlinear autoregressive network with exogenous inputs based contour error reduction in CNC machines

A new approach for reducing the contour errors in two-dimensional CNC machines is presented in this study. In the approach proposed here, two pre-trained nonlinear autoregressive networks with exogenous inputs (NARX), one for each axis, are used to predict the output position of the machine in the next sampling instant. The contour error in the next instant is then estimated and, based on this, the required compensation terms to be added to the reference input positions to reduce the contour error are determined. In the proposed approach, the compensation terms can be updated through an iteration process which reduces the contour error each time. Simulation experiments applying this approach to linear, circular and parabolic contours show that, even without extensive training of the NARX models, the contour errors can be significantly reduced. Actual experiments conducted on a small two-axis CNC machine confirm the effectiveness of this approach in reducing contour errors for linear, circular, parabolic and a free-form “goggles” contours.

1917 平歯車列機構創成問題に対する多目的最適化手法の有効性の検討

In our study, a design system is developed for generating gear trains under design constraints in a specified area The design specifications are input position, output position, input torque, output torque, rotation direction, and so on Spur gear trains are generated by using random method combined with local optimization method The objective function evaluates weight, efficiency and operating life of generated gear train Multi-objective design optimizations in spur gear train generation problems are examined by the gear tram generation system The advantage of the optimization approach to generating effective gear trains is reported through several examples

Functional Observers for Motion Control Systems

This paper presents a novel functional observer for motion control systems to provide higher accuracy and less noise in comparison to existing observers. The observer uses the input current and position information along with the nominal parameters of the plant and can observe the velocity, acceleration and disturbance information of the system. The novelty of the observer is based on its functional structure that can intrinsically estimate and compensate the un-measured inputs (like disturbance acting on the system) using the measured input current. The experimental results of the proposed estimator verifies its success in estimating the velocity, acceleration and disturbance with better precision than other second order observers.

Dynamic behavior of spatial solitons propagating along Scarf II parity–time symmetric cells

Using a nonstationary state solution to the nonlinear Schrodinger equation (NLSE), we report the results of our numerical investigation on the swing behavior of spatial solitons propagating along waveguides whose refractive indices in the transverse direction are perturbed by Scarf II type parity–time symmetric profiles. We show that solitons, after entering parity–time symmetry (PTS) cells with Scarf II profiles will, in general, swing along the waveguide with nonuniform amplitude and period. Nevertheless, it is demonstrated that when the average incident position in the transverse direction is set at the center of the profile symmetry and the amplitude of the incident soliton exceeds a specific value, the soliton behavior could be approximated by a stationary-state solution to the NLSE and say it is almost self-trapped. Simulation also shows that, depending on the soliton’s initial average transverse input position, the swing behavior could be greatly influenced by the nonreciprocity of PTS cells.

Serial-position effects for items and relations in short-term memory

Two experiments used immediate probed recall of words to investigate serial-position effects. Item memory was tested through probing with a semantic category. Relation memory was tested through probing with the word's spatial location of presentation. Input order and output order were deconfounded by presenting and probing items in different orders. Primacy and recency effects over input position were found for both item memory and relation memory. Both item and relation memory declined over output position. The finding of a U-shaped input position function for item memory rules out an explanation purely in terms of positional confusions (e.g., edge effects). Either these serial-position effects arise from variations in the intrinsic memory strength of the items, or they arise from variations in the strength of item–position bindings, together with retrieval by scanning.

Spectroscopic diagnostics and modelling of a N2–Ar mixture discharge created by an RF helical coupling device: I. Kinetics of N2(B 3Πg) and N2(C 3Πu) states

Optical emission spectroscopy, ranging from visible to near infrared, is used to determine densities and rotational temperatures of N2(B 3Πg) and N2(C 3Πu) states in a nitrogen–argon (0–95% Ar) discharge, under moderate pressures (200–400 Pa). The plasma is sustained by a helical cavity with an excitation frequency of 27 MHz and power fixed to 28 W. Firstly, in the case of a pure N2 discharge, the two states turn out to have a similar rotational temperature, which approximates the gas temperature reasonably well. With a gradual increase in the Ar concentration up to 95%, the rotational temperature of N2(C 3Πu) roughly doubles while that of N2(B 3Πg) stays unchanged at 430 ± 50 K regardless of the gas composition. Secondly, as observed, the densities of the N2(B 3Πg) and N2(C 3Πu) states increase with increasing Ar percentage in the gas mixture. The increase in the emission intensity values is less marked for positions corresponding to both ends of the cavity. In fact, the difference in the emission level between the power input and helix middle positions is reduced, revealing that the total discharge is more uniform along the cavity for large argon concentrations. The experimental results show a strong dependence of temperatures and densities on the Ar amount in the gas mixture. A kinetic model is developed to explain this phenomenon, which is then used in modelling density evolutions versus relative abundance of Ar and versus the position along the cavity axis. The model indicates the importance of the role of electron and metastable species in the above-described discharge.

Soliton dynamics induced by periodic spatially inhomogeneous losses in optical media described by the complex Ginzburg–Landau model

We study the rich dynamics of dissipative spatial solitons in optical media described by the complex Ginzburg–Landau equation in the presence of periodic, sinusoidal-type spatially inhomogeneous losses. It is revealed that in the case when the soliton is launched at the point where the periodic spatial modulation loss profile has its zero value, the gradient force of the inhomogeneous loss easily induces three generic propagation scenarios: (a) soliton transverse drift, (b) persistent swing around the soliton input launching position, and (c) damped oscillations near or even far from the input position. The soliton exhibiting damped oscillations eventually evolves into a stable one, whose output position can be controlled by the amplitude of the inhomogeneous loss profile. Conversely, when the launching point coincides with an extremum (a maximum or a minimum) of the sinusoidal-type loss landscape, both soliton transverse drift and soliton damped oscillations occur due to transverse modulation instability. Moreover, in this case, depending on the balance between the amplitude of the inhomogeneous loss modulation profile and the homogeneous linear loss coefficient, either the launched soliton can maintain its stable propagation at the input position or a stable plump dissipative soliton can be formed while preserving the launching point.

SU-E-J-126: Generation of Fluoroscopic 3D Images Using Single X-Ray Projections on Realistic Modified XCAT Phantom Data.

To simulate the process of generating fluoroscopic 3D treatment images from 4DCT and measured 2D x-ray projections using a realistic modified XCAT phantom based on measured patient 3D tumor trajectories. First, the existing XCAT phantom is adapted to incorporate measured patient lung tumor trajectories. Realistic diaphragm and chest wall motion are automatically generated based on input tumor motion and position, producing synchronized, realistic motion in the phantom. Based on 4DCT generated with the XCAT phantom, we derive patient-specific motion models that are used to generate 3D fluoroscopic images. Patient-specific models are created in two steps: first, the displacement vector fields (DVFs) are obtained through deformable image registration of each phase of 4DCT with respect to a reference image (typically peak-exhale). Each phase is registered to the reference image to obtain (n-1) DVFs. Second, the most salient characteristics in the DVFs are captured in a compact representation through principal component analysis (PCA). Since PCA is a linear decomposition method, all the DVFs can be represented as linear combinations of eigenvectors. Fluoroscopic 3D images are obtained using the projection image to determine optimal weights for the eigenvectors. These weights are determined through iterative optimization of a cost function relating the projection image to the 3D image via the PCA lung motion model and a projection operator. Constructing fluoroscopic 3D images is thus reduced to finding optimal weights for the eigenvectors. Fluoroscopic 3D treatment images were generated using the modified XCAT phantom. The average relative error of the reconstructed image over 30 sec is 0.0457 HU and the standard deviation is 0.0063. The XCAT phantom was modified to produce realistic images by incorporating patient tumor trajectories. The modified XCAT phantom can be used to simulate the process of generating fluoroscopic 3D treatment images from 4DCT and 2D x-ray projections.

A Yank-Based Variable Coefficient Method for a Low-Powered Semi-Active Power Assist System

In this paper, we developed a power assist system to help users on carrying heavy loads. This system uses the user input force and position to generate an aiding force, reducing the burden on carrying heavy loads. We adopted a semi-active methodology, combining an active with a passive element, aiming to match the best traits from both, and also considering a lighter motor, which makes the system reach its limit force. To control this lightly actuated semi-active system we proposed a proportional controller which has its gain tuned accordingly to the yank value; this is calculated by the derivative of the force. The controller method herein amplifies the system response whenever the user intends to change his movement, producing a better handling of the system and saving actuator power for either periodical or non-periodical movements. Future applications may involve creating a light assist system for portable applications or assist in heavy industrial environments.

Iterative Channel Decoding for PC-Based Software Radio DVB-T Receiver

The previous scheme only modifies the Viterbi decoder input positions where the Reed-Solomon decoder makes sure they are correct. Although it is simple and can get perfect image quality in static channels, it still suffer image quality degradation in mobile channels. Besides that, we propose to change the parameter Q of the metrics of the Viterbi decoder input positions where the Reed-Solomon decoder makes sure they are incorrect. The Q is defined as the norm of channel state information (CSI), Q = |CSI|2. We propose to change Q to maximum for the Viterbi decoder input positions where the Reed-Solomon decoder makes sure they are incorrect, so the incorrect paths are unlikely to be selected in the Viterbi algorithm. The field test results in 100 km/h moving speed show that the proposed scheme with Q modification outperforms the previous scheme without Q modification by 0.36 % (7.45--->7.09 %) in symbol error rate and noticeable image quality difference.

2207 平歯車列機構設計におけるトレードオフ関係の検討(OS6-2 設計と最適化II)

Mechanism design becomes more complicated to achieve higher mechanical functions. It is necessary to create appropriate configuration and geometry at upstream design stage to satisfy design specifications at detail design stage. In our study, a design system is developed for generating gear trains under design constraints on a specified area. The design specifications are input position, output position, input torque, output torque, rotation direction, total weight and so on. Spur gear trains are generated by using random method combined with local optimization method based on the conjugate gradient method. The objective function evaluates weight, efficiency and life of generated gear train. For several examples, optimal gear trains are generated successfully. Trade-off relationships in spur gear train design are examined by the optimization system. The effectiveness of the mechanism generation algorithm is reported.

2A1-G07 平歯車列機構最適設計システムの開発 : 構成要素に関する制約の検討(【機械力学・計測制御部門】ロボットシステムのダイナミクス&デザイン)

In recent years, mechanism design becomes more complicated to achieve higher mechanical function and efficiency. It is necessary to create appropriate configuration and geometry at upstream design stage to satisfy design specifications at detail design stage. In our study, a design system is developed for generating gear trains under design constraints on specified area. The design specifications are input position, output position, input torque, output torque, rotation direction, total weight and so on. Spur gear trains are generated by using random method combined with local optimization based on CGM. The objective function evaluates weight, efficiency, life of generated gear train. For several examples, the optimum gear train is generated successfully. The effectiveness of the optimum design system is reported.

The dynamics of access to groups in working memory.

The finding that participants leave a pause between groups when attempting serial recall of temporally grouped lists has been taken to indicate access to a hierarchical representation of the list in working memory. An alternative explanation is that the dynamics of serial recall solely reflect output (rather than memorial) processes, with the temporal pattern at input merely suggesting a basis for the pattern of output buffering. Three experiments are presented here that disentangle input structure from output buffering in serial recall. In Experiment 1, participants were asked to recall a subset of visually presented digits from a temporally grouped list in their original order, where either within-group position or group position was kept constant. In Experiment 2, participants performed more standard serial recall of spoken digits, and input and output position were dissociated by asking participants to initiate recall from a post-cued position in the list. In Experiment 3, participants were asked to serially recall temporally grouped lists of visually presented digits where the grouping structure was unpredictable, under either articulatory suppression or silent conditions. The 3 experiments point to a tight linkage between implied memorial structures (i.e., the pattern of grouping at encoding) and the output structure implied by retrieval times and call into question a purely motoric account of the dynamics of recall.

Three-Query Locally Decodable Codes with Higher Correctness Require Exponential Length

Locally decodable codes are error-correcting codes with the extra property that, in order to retrieve the value of a single input position, it is sufficient to read a small number of positions of the codeword. We refer to the probability of getting the correct value as the correctness of the decoding algorithm. A breakthrough result by Yekhanin [2007] showed that 3-query linear locally decodable codes may have subexponential length. The construction of Yekhanin, and the three query constructions that followed, achieve correctness only up to a certain limit which is 1 − 3 δ for nonbinary codes, where an adversary is allowed to corrupt up to δ fraction of the codeword. The largest correctness for a subexponential length 3-query binary code is achieved in a construction by Woodruff [2008], and it is below 1 − 3 δ . We show that achieving slightly larger correctness (as a function of δ ) requires exponential codeword length for 3-query codes. Previously, there were no larger than quadratic lower bounds known for locally decodable codes with more than 2 queries, even in the case of 3-query linear codes. Our lower bounds hold for linear codes over arbitrary finite fields and for binary nonlinear codes. Considering larger number of queries, we obtain lower bounds for q-query codes for q > 3, under certain assumptions on the decoding algorithm that have been commonly used in previous constructions. We also prove bounds on the largest correctness achievable by these decoding algorithms, regardless of the length of the code. Our results explain the limitations on correctness in previous constructions using such decoding algorithms. In addition, our results imply trade-offs on the parameters of error-correcting data structures.

Developing Speech Input for Virtual Applications

This paper contextualises the position of speech input from a user-centred human factors perspective. It is presented as a position paper so that researchers and designers can consider the underlying and future factors of a people-orientated approach to speech input for virtual applications. A number of key areas are explored including: human factors for speech input; speech input for virtual applications; speech as a spare mode of interaction; user acceptance and uptake; incorporating speech in the development of virtual applications; and speech input as an interaction tool. Given the user-centred perspective of this paper, this paper does not set out to address issues associated with spoken dialogue technologies, dialogue, and dialogue management; recent work on conversational agents in virtual environments; or multimodal interaction. This paper places the focus more fundamentally within human factors by looking at the user first as a basis for developing usable virtual applications incorporating speech input rather than to review the current state of the art in interaction design. A particular point this paper makes, however, is that speech input should be designed and used as another interaction tool that users need to learn to use, rather than assuming it will offer a natural or intuitive interface.