Evaluation of structure specification in linear mixed models for modeling the spatial effects in tree height-diamater relationships

In recent years, linear mixed models (LMM) have become more popularto deal with spatial effects in forestry and ecological data. In this study, different structure specifications of linear mixed model were applied to model tree height-diameter relationships, including LMM with random blocks only (LMM-block), LMM with spatial covariance only (LMM-covariance), and the combination of the last two (LMM-block-covariance). Further, the between group heterogeneous variances were incorporated into LMM-covariance and LMM-block-covariance. The results indicated that, in general, LMM-covariance significantly reduced spatial autocorrelation in model residuals, while LMM-block was effective in dealing with spatial heterogeneity. LMM-blocktreated the blocks as random effects and avoided the estimation of parameters of the variogram model. Thus, it produced better model predictions than LMM-covariance. LMM-block-covariance took both block effects and spatial covariance into account, and significantly improve model fitting. However, it did not produce better model predictions due to the increase of model complexity and estimation of the local variogram within each block

Relationships between overstory species and community classification of the Sipsey Wilderness, Alabama

A total of 2314 trees was sampled from 170 randomly located plots to investigate ecological community relationships and species similarities of the vegetation covering the 12 000 ha Sipsey Wilderness in Alabama. Thirty-two tree species, 14 vegetation types and 10 landtypes were identi®ed. Within each plot, the species were ranked based on their basal area to determine the relative importance of the species. A variety of species including white oak (Quercus alba L.), post oak (Quercus stellata Wangenh.), chestnut oak (Quercus prinus L.), northern red oak (Quercus rubra L.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), loblolly pine (Pinus taeda L.), virginia pine (Pinus virginiana Mill.), pignut hickory (Carya glabra Sweet) and yellow poplar (Liriodendron tulipifera L.) were important species differentiating the ecological communities. Percent basal area (BA%) of each species in the plots was also computed. The vegetation-types and landtypes were characterized by average ranks and BA% of the species. Relationships between the vegetation-types were examined by cluster analysis

Dynamic Evolutionary Game Analysis of Symbiosis System in E-commerce Industrial Park

Based on the evolutionary game theory and the bounded rational and asymmetric information assumptions, we construct the dynamic evolutionary game model between the three game players and analyze the replication dynamic equations. Furthermore, we analyze the strategy of three symbiosis units and the evolution mechanism of E-commerce industrial park symbiosis system. Finally, two conclusions are drawn: Conclusion 1, the probability that three symbiosis units of E-commerce Industrial Park choosing the symbiosis strategy increases with increase of the probability that the other two symbiosis units selecting the symbiosis strategy. Conclusion 2, the probability of the symbiosis unit to choose the symbiosis strategy increase with the increase of the benefit and decrease with the increase of the cost, risk and loss

Identification of a male-specific amplified fragment length polymorphism (AFLP) marker in Broussonetia papyrifera

The present study exhibits amplified fragment length polymorphism (AFLP) molecular marker for sex identification in Broussonetia papyrifera. Based on nine selective amplification primer combinations, 230 bands were produced and the E-AGG/M-CAA combination was found to be a male-specific AFLP marker. Subsequently, this male-specific AFLP fragment was sequenced and converted into a sequence tagged site (STS) marker. Based on STS sequence, two primers, MADB-1 and MADB-2 (Male-Associated DNA from B. papyrifera), were designed to verify the specificity of the fragment. The results indicate that common homology sequence is existed in both male and female plants while one of the bands amplified via MADB-2 primer was solely present in male individuals at high annealing temperature up to 66°C. Finally, MADB-2 primer was introduced to amplify another 16 plants and it revealed that this primer could be used as a convenient, efficient, reliable, and low-cost molecular marker for sex identification in B. papyrifera.Keywords: Broussonetia papyrifera, AFLP, STS, male-specific marke

Detect to Learn: Structure Learning with Attention and Decision Feedback for MIMO-OFDM Receive Processing

The limited over-the-air (OTA) pilot symbols in multiple-input-multiple-output orthogonal-frequency-division-multiplexing (MIMO-OFDM) systems presents a major challenge for detecting transmitted data symbols at the receiver, especially for machine learning-based approaches. While it is crucial to explore effective ways to exploit pilots, one can also take advantage of the data symbols to improve detection performance. Thus, this paper introduces an online attention-based approach, namely RC-AttStructNet-DF, that can efficiently utilize pilot symbols and be dynamically updated with the detected payload data using the decision feedback (DF) mechanism. Reservoir computing (RC) is employed in the time domain network to facilitate efficient online training. The frequency domain network adopts the novel 2D multi-head attention (MHA) module to capture the time and frequency correlations, and the structural-based StructNet to facilitate the DF mechanism. The attention loss is designed to learn the frequency domain network. The DF mechanism further enhances detection performance by dynamically tracking the channel changes through detected data symbols. The effectiveness of the RC-AttStructNet-DF approach is demonstrated through extensive experiments in MIMO-OFDM and massive MIMO-OFDM systems with different modulation orders and under various scenarios.Comment: Accepted to IEEE Transactions on Communication