Children's naming and word-finding difficulties: descriptions and explanations

Purpose: There are a substantial minority of children for whom lexical retrieval problems impede the normal pattern of language development and use. These problems include accurately producing the correct word even when the word?s meaning is understood; such children are often referred to as having word-finding difficulties (WFDs). This review examines the nature of naming and lexical retrieval difficulties in these and other groups of children. Method: A review of the relevant literature on lexical access difficulties in children with word finding difficulties was conducted. Studies were examined in the terms of population parameters and comparison groups included in the study. Results and Conclusions: Most discussions of the cognitive processes causing lexical retrieval difficulties have referred to semantics, phonology and processing speed. It is argued that our understanding of these topics will be further advanced by the use of appropriate methodology to test developmental models that both identify the processes in successfully performing different lexical retrieval tasks and more precisely locating the difficulties experienced by children with such tasks

A simple implementation of the Viterbi algorithm on the Motorola DSP56001

As systems designers design communication systems with digital rather than analog components to reduce noise and increase channel capacity, they must have the ability to perform traditional communication algorithms digitally. The use of trellis coded modulation as well as the extensive use of convolutional encoding for error detection and correction requires an efficient digital implementation of the Viterbi Algorithm for real time demodulation and decoding. Digital signal processors are now fast enough to implement Viterbi decoding in conjunction with the normal receiver/transmitter functions for lower speed channels on a single chip as well as performing fast decoding for higher speed channels, if the algorithm is implemented efficiently. The purpose of this paper is to identify a good way to implement the Viterbi Algorithm (VA) on the Motorola DSP56001, balancing performance considerations with speed and memory efficiency

FOREWORD: Special Issue on Experimental Methods in Environmental, Natural Resource, and Agricultural Economics

Agricultural and Food Policy, Environmental Economics and Policy, Institutional and Behavioral Economics, Research Methods/ Statistical Methods,

"Applying Optimization and the Analytic Hierarchy Process to Enhance Agricultural Preservation Strategies in the State of Delaware"

Using agricultural preservation priorities derived from an analytical hierarchy process by 23 experts from 18 agencies in the State of Delaware, this research uses weighted suitability attributes to evaluate the historical success of the State of Delaware’s agricultural protection fund, which spent nearly $100 million in its first decade. This research demonstrates how these operation research techniques can be used on concert to address relevant conservation questions. Results suggest that the state’s sealed-bid-offer auction, which determines the yearly conservation selections, is superior to benefit targeting approaches frequently employed by conservation organizations but is inferior to the optimization technique of binary linear programming that could have provided additional benefits to the state, such as 12,000 additional acres worth an estimated$25 million.Conservation Optimization, Farmland Protection, Analytic Hierarchy Process

Matching Grants and Charitable Giving: Why People Sometimes Provide a Helping Hand to Fund Environmental Goods

Matching grants are a prevalent mechanism for funding environmental, conservation, and natural resource projects. However, economists have largely been silent regarding the potential benefits of these mechanisms at increasing voluntary contributions. To examine the behavioral responses to different match levels, this research uses controlled laboratory experiments with generically framed instructions and introduces a general-form matching-grant mechanism, referred to as the proportional contribution mechanism (PCM). Results show that contributions are positively correlated with both the match and the induced value of the public good even when a dominant strategy is free-riding. An implication of this partial demand revelation result is that manifestations of this type of “helping hand†social preference should be counted in benefit-cost analysis.matching grants, public goods, charitable giving, voluntary contributions, experimental economics, warm glow, helping hand, Environmental Economics and Policy, Public Economics,

Applying Optimization and the Analytic Hierarchy Process to Enhance Agricultural Preservation Strategies in the State of Delaware

Using agricultural preservation priorities derived from an analytical hierarchy process by 23 conservation experts from 18 agencies in the state of Delaware, this research uses weighted benefit measures to evaluate the historical success of Delaware’s agricultural protection fund, which spent nearly $100 million in its first decade. This research demonstrates how these operation research techniques can be used in concert to address relevant conservation questions. Results suggest that the state’s sealed-bid-offer auction, which determines the yearly conservation selections, is superior to benefit-targeting approaches frequently employed by conservation organizations, but is inferior to the optimization technique of binary linear programming that could have provided additional benefits to the state, such as 12,000 additional acres worth an estimated$25 million.conservation optimization, farmland protection, analytic hierarchy process, binary linear programming, Environmental Economics and Policy, Land Economics/Use, Research and Development/Tech Change/Emerging Technologies,

Do children use different forms of verbal rehearsal in serial picture recall tasks? A multi-method study

Use of verbal rehearsal is a key issue in memory development. However, we still lack detailed and triangulated information about the early development and the circumstances in which different forms of rehearsal are used. To further understand significant factors that affect children’s use of various forms of rehearsal, the present study involving 108 primary school children adopted a multi-method approach. It combined a carefully chosen word length effect method with a self-paced presentation time method to obtain behavioural indicators of verbal rehearsal. In addition, subsequent trial-by-trial self-reports were gathered. Word length effects in recall suggested that phonological recoding (converting images to names - a necessary precursor for rehearsal) took place, with evidence of more rehearsal among children with higher performance levels. According to self-paced presentation times, cumulative rehearsal was the dominant form of rehearsal only for children with higher spans on difficult trials. The combined results of self-paced times and word length effects in recall suggest that ‘naming’ as simple form of rehearsal was dominant for most children. Self-reports were in line with these conclusions. Additionally, children used a mixture of strategies with considerable intra-individual variability, yet strategy use was nevertheless linked to age as well as performance levels

Status-Quo-Bias and Voluntary Contributions: Can Lab Experiments Parallel Real World Outcomes for Generic Advertising?

Many commodities have programs assessing producers for generic advertising. Ads such as "Got Milk?" and the "Incredible Edible Egg" are a public good for producers. Most of these programs originally used the Voluntary Contribution Mechanism, but have now become mandatory because of free-riding. This research simulates both the economic and psychological details of the egg industry in experiments that produce strikingly realistic results. Because mandatory programs have recently been declared unconstitutional, we also the test the Provision Point Mechanism and show that observed low levels of free-riding for both mechanisms are the result of status quo bias.Marketing, H40, H41, M37,

Acoustic echo cancellation for full-duplex voice transmission on fading channels

This paper discusses the implementation of an adaptive acoustic echo canceler for a hands-free cellular phone operating on a fading channel. The adaptive lattice structure, which is particularly known for faster convergence relative to the conventional tapped-delay-line (TDL) structure, is used in the initialization stage. After convergence, the lattice coefficients are converted into the coefficients for the TDL structure which can accommodate a larger number of taps in real-time operation due to its computational simplicity. The conversion method of the TDL coefficients from the lattice coefficients is derived and the DSP56001 assembly code for the lattice and TDL structure is included, as well as simulation results and the schematic diagram for the hardware implementation