Integrated semantic processing of complex pictures and spoken sentences - Evidence from event-related potentials

It has been suggested that semantic information processing is modularized according to the input form (e.g., visual, verbal, non-verbal sound). A great deal of research has concentrated on detecting a separate verbal module. Also, it has traditionally been assumed in linguistics that the meaning of a single clause is computed before integration to a wider context. Recent research has called these views into question. The present study explored whether it is reasonable to assume separate verbal and nonverbal semantic systems in the light of the evidence from event-related potentials (ERPs). The study also provided information on whether the context influences processing of a single clause before the local meaning is computed. The focus was on an ERP called N400. Its amplitude is assumed to reflect the effort required to integrate an item to the preceding context. For instance, if a word is anomalous in its context, it will elicit a larger N400. N400 has been observed in experiments using both verbal and nonverbal stimuli. Contents of a single sentence were not hypothesized to influence the N400 amplitude. Only the combined contents of the sentence and the picture were hypothesized to influence the N400. The subjects (n = 17) viewed pictures on a computer screen while hearing sentences through headphones. Their task was to judge the congruency of the picture and the sentence. There were four conditions: 1) the picture and the sentence were congruent and sensible, 2) the sentence and the picture were congruent, but the sentence ended anomalously, 3) the picture and the sentence were incongruent but sensible, 4) the picture and the sentence were incongruent and anomalous. Stimuli from the four conditions were presented in a semi-randomized sequence. Their electroencephalography was simultaneously recorded. ERPs were computed for the four conditions. The amplitude of the N400 effect was largest in the incongruent sentence-picture -pairs. The anomalously ending sentences did not elicit a larger N400 than the sensible sentences. The results suggest that there is no separate verbal semantic system, and that the meaning of a single clause is not processed independent of the context.

Pole placement in multi-input systems via elementary transformations

This paper is concerned with the development of an algorithm for pole placement in multi-input dynamic systems. The algorithm which uses a series of elementary transformations is believed to be simpler, computationally more efficient and numerically stable when compared with earlier methods. In this paper two methods have been presented.

Incidence factors of the tracking systems used in parabolic-cylindrical concentrators

Several orientation and tracking systems employed in parabolic-cylindrical concentrators for focusing the direct solar radiation on the absorber tubes are analyzed from the technical and economic points of view. Case one, where the incidence factor was a function of declination and hour angle, showed that the maximum variations of incident factor from morning to noon was 0.5 at zero angle of declination. Case two, where the incidence factor was a function of declination, hour angle and latitude, showed the maximum variation of the incidence factor to be 0.128, which occurred during noon at the latitude of 30 degrees, corresponding to a change of declination from 0 to 23.5 degrees. In case three, the incidence factor, a function of declination only, showed that the maximum variation of the incidence factor corresponding to the change in declination from 0 to 23.5 degree was 0.0758. It is concluded that system three is the most efficient from the technical and economic point of view.

Real-time wide-area loading margin sensitivity (WALMS) in power systems

Loading margin sensitivity (LMS) has been widely used in applications in the realm of voltage stability assessment and control. Typically, LMS is derived based on system equilibrium equations near bifurcation and therefore requires full detailed system model and significant computation effort. Availability of phasor measurement units (PMUs) due to the recent development of wide-area monitoring system (WAMS) provides an alternative computation-friendly approach for calculating LMS. With such motivation, this work proposes measurement-based wide-area loading margin sensitivity (WALMS) in bulk power systems. The proposed sensitivity, with its simplicity, has great potential to be embedded in real-time applications. Moreover, the calculation of the WALMS is not limited to low voltage near bifurcation point. A case study on IEEE 39-bus system verifies the proposed sensitivity. Finally, a voltage control scenario demonstrates the potential application of the WALMS.

Probabilistic load flow for distribution systems with uncertain PV generation

Large integration of solar Photo Voltaic (PV) in distribution network has resulted in over-voltage problems. Several control techniques are developed to address over-voltage problem using Deterministic Load Flow (DLF). However, intermittent characteristics of PV generation require Probabilistic Load Flow (PLF) to introduce variability in analysis that is ignored in DLF. The traditional PLF techniques are not suitable for distribution systems and suffer from several drawbacks such as computational burden (Monte Carlo, Conventional convolution), sensitive accuracy with the complexity of system (point estimation method), requirement of necessary linearization (multi-linear simulation) and convergence problem (Gram–Charlier expansion, Cornish Fisher expansion). In this research, Latin Hypercube Sampling with Cholesky Decomposition (LHS-CD) is used to quantify the over-voltage issues with and without the voltage control algorithm in the distribution network with active generation. LHS technique is verified with a test network and real system from an Australian distribution network service provider. Accuracy and computational burden of simulated results are also compared with Monte Carlo simulations.

Performance Study of a Centralized Concurrency Control Algorithm for Distributed Database Systems using SIMULA

The stimulation technique has gained much importance in the performance studies of Concurrency Control (CC) algorithms for distributed database systems. However, details regarding the simulation methodology and implementation are seldom mentioned in the literature. One objective of this paper is to elaborate the simulation methodology using SIMULA. Detailed studies have been carried out on a centralised CC algorithm and its modified version. The results compare well with a previously reported study on these algorithms. Here, additional results concerning the update intensiveness of transactions and the degree of conflict are obtained. The degree of conflict is quantitatively measured and it is seen to be a useful performance index. Regression analysis has been carried out on the results, and an optimisation study using the regression model has been performed to minimise the response time. Such a study may prove useful for the design of distributed database systems.

Two Tools for Interprocess Communication in Distributed Data-Flow Systems

Abstract is not available.

On the sufficient conditions for the equality of the unassignable polynomial and Davison's fixed polynomial of strongly connected systems

In this technical note, it is established that the unassignable polynomial defined for a not strongly connected decentralized control system is not equal to Davison's fixed polynomial. This leads to a "sufficient condition" for the equality of the unassignable polynomial and Davison's fixed polynomial for strongly connected systems.

Functional programming systems revisited

Functional Programming (FP) systems are modified and extended to form Nondeterministic Functional Programming (NFP) systems in which nondeterministic programs can be specified and both deterministic and nondeterministic programs can be verified essentially within the system. It is shown that the algebra of NFP programs has simpler laws in comparison with the algebra of FP programs. "Regular" forms are introduced to put forward a disciplined way of reasoning about programs. Finally, an alternative definition of "linear" forms is proposed for reasoning about recursively defined programs. This definition, when used to test the linearity of forms, results in simpler verification conditions than those generated by the original definition of linear forms.

Improving management of summer weeds in dryland cropping systems with Cotton

In 2001 a scoping study (phase I) was commissioned to determine and prioritise the weed issues of cropping systems with dryland cotton. The main findings were that the weed flora was diverse, cropping systems complex, and weeds had a major financial and economical impact. Phase II 'Best weed management strategies for dryland cropping systems with cotton' focused on improved management of the key weeds, bladder ketmia, sowthistle, fleabane, barnyard grass and liverseed grass.In Phase III 'Improving management of summer weeds in dryland cropping systems with cotton', more information on the seed-bank dynamics of key weeds was gained in six pot and field studies. The studies found that these characteristics differed between species, and even climate in the case of bladder ketmia. Species such as sowthistle, fleabane and barnyard grass emerged predominately from the surface soil. Sweet summer grass was also in this category but also had a significant proportion emerging from 5 cm depth. Bladder ketmia in central Queensland emerged mainly from the top 2 cm, whereas in southern Queensland it emerged mainly from 5 cm. Liverseed grass had its highest emergence from 5 cm below the surface. In all cases the persistence of seed increased with increasing soil depth. Fleabane was also found to be sensitive to soil type with no seedlings emerging in the self-mulching black vertisol soil. A strategic tillage trial showed that burial of fleabane seed, using a disc or chisel plough, to a depth of greater than 2 cm can significantly reduce subsequent fleabane emergence. In contrast, tillage increased barnyard grass emergence and tended to decrease persistence. This research showed that weed management plans can not be blanketed across all weed species, rather they need to be targeted for each main weed species.This project has also resulted in an increased knowledge of how to manage fleabane from the eight experiments; one in wheat, two in sorghum, one in cotton and three in fallow on double knock. For summer crops, the best option is to apply a highly effective fallow treatment prior to sowing the crops. For winter crops, the strategy is the integration of competitive crops, residual herbicide followed by a knockdown to control survivors. This project explored further the usefulness of the double knock tactic for weed control and preventing seed set. Two field and one pot experiments have shown that this tactic was highly effective for fleabane control. Paraquat products provided good control when followed by glyphosate. When 2, 4-D was added in a tank mix with glyphosate and followed by paraquat products, 99-100% control was achieved in all cases. The ideal follow-up times for paraquat products after glyphosate were 5-7 days. The preferred follow-up times for 2, 4-D after glyphosate were on the same day and one day later. The pot trial, which compared a population from a cropping field with previous glyphosate exposure and a population from a non-cropping area with no previous glyphosate herbicide exposure, showed that the pervious herbicide exposure affected the response of fleabane to herbicidal control measures. The web-based brochure on managing fleabane has been updated.Knowledge on management of summer grasses and safe use of residual herbicides was derived from eight field and pot experiments. Residual grass and broadleaf weed control was excellent with atrazine pre-plant and at-planting treatments, provided rain was received within a short interval after application. Highly effective fallow treatments (cultivation and double knock), not only gave excellent grass control in the fallow, also gave very good control in the following cotton. In the five re-cropping experiments, there were no adverse impacts on cotton from atrazine, metolachlor, metsulfuron and chlorsulfuron residues following use in previous sorghum, wheat and fallows. However, imazapic residues did reduce cotton growth.The development of strategies to reduce the heavy reliance on glyphosate in our cropping systems, and therefore minimise the risk of glyphosate resistance development, was a key factor in the research undertaken. This work included identifying suitable tactics for summer grass control, such as double knock with glyphosate followed by paraquat and tillage. Research on fleabane also concentrated on minimising emergence through tillage, and applying the double knock tactic. Our studies have shown that these strategies can be used to prevent seed set with the goal of driving down the seed bank. Utilisation of the strategies will also reduce the reliance on glyphosate, and therefore reduce the risk of glyphosate resistance developing in our cropping systems.Information from this research, including ecological and management data were collected from an additional eight paddock monitoring sites, was also incorporated into the Weeds CRC seed bank model "Weed Seed Wizard", which will be able to predict the impact of different management options on weed populations in cotton and grain farming systems. Extensive communication activities were undertaken throughout this project to ensure adoption of the new strategies for improved weed management and reduced risk for glyphosate resistance.