6,342 research outputs found
Impact of Organic Crop and Livestock Systems on Earthworm Population Dynamics
Earthworm population dynamics and diversity were evaluated in long-term farming systems experiments at the West Virginia University Organic Research Farm from 2000-2007. Farming systems included vegetable and field crop rotations, with versus without annual compost amendments. Field crop rotations with livestock included three years of clover-grassland. Earthworms were monitored by hand-sorting soil samples. Aporrectodea caliginosa and Lumbricus rubellus were the most common species observed. Cultivation adversely affected earthworm populations in all systems, while compost amendments either had no effect or increased earthworm populations. The population structure shifted toward younger age classes and lower biomass. Inclusion of clover-grassland in the rotation for pasture and hay production for sheep had no significant effects on populations in the field crop systems
Evidence of coevolution in multi-objective evolutionary algorithms
This paper demonstrates that simple yet important characteristics of coevolution can occur in evolutionary algorithms when only a few conditions are met. We find that interaction-based fitness measurements such as fitness (linear) ranking allow for a form of coevolutionary dynamics that is observed when 1) changes are made in what solutions are able to interact during the ranking process and 2) evolution takes place in a multi-objective environment. This research contributes to the study of simulated evolution in a at least two ways. First, it establishes a broader relationship between coevolution and multi-objective optimization than has been previously considered in the literature. Second, it demonstrates that the preconditions for coevolutionary behavior are weaker than previously thought. In particular, our model indicates that direct cooperation or competition between species is not required for coevolution to take place. Moreover, our experiments provide evidence that environmental perturbations can drive coevolutionary processes; a conclusion that mirrors arguments put forth in dual phase evolution theory. In the discussion, we briefly consider how our results may shed light onto this and other recent theories of evolution
Economic Integration Between China And ASEAN
With the signing in November 2001 of a China-ASEAN free trade agreement due for completion in 2010, the question of the current degree of economic integration between China and ASEAN becomes important. This papers uses international parity conditions to investigate this issue. The results indicate that China is already highly integrated with ASEAN with respect to trade in goods and services. Financial integration however remains significantly incomplete. Given that external bodies such as the WTO will increasingly dictate the pace of China's future financial liberalization, the main implication of these findings is that complimentary reforms, such as the upgrading of prudential frameworks, need to be completed as a matter of urgency in both China and ASEAN.
Credit Assignment in Adaptive Evolutionary Algorithms
In this paper, a new method for assigning credit to search\ud
operators is presented. Starting with the principle of optimizing\ud
search bias, search operators are selected based on an ability to\ud
create solutions that are historically linked to future generations.\ud
Using a novel framework for defining performance\ud
measurements, distributing credit for performance, and the\ud
statistical interpretation of this credit, a new adaptive method is\ud
developed and shown to outperform a variety of adaptive and\ud
non-adaptive competitors
External Financial Liberalization and Foreign Debt in China
China has not been a large net capital importer during the reform period (1979-present). This is surprising because economic theory predicts it should have been in light of its low capital - labour ratio. One possible explanation with important policy implications is that foreign capital inflows may have been restricted due to the slow pace of external financial liberalization. The empirical analysis conducted in this paper lends support to this hypothesis. However, before policy makers in China can look upon external financial liberalization as a growth-inducing strategy, fiscal reform and greater levels of domestic financial liberalization are first needed.
The Impact of Stock Markets on China's Economic Development: Some Preliminary Assessments
The role that stock markets should be afforded in economic development policy in China is the subject of debate. Some argue that they are essential to reforming state-owned enterprises (SOE's) and overcoming deficiencies in China's credit markets. However, others claim they are not necessary institutions for achieving high levels of economic development and are more likely to be destabilizing. This paper seeks to shed light on the impact that stock markets have had on China's economic development to date. Available data suggests that listing SOE's has been important in terms of raising funds for their reform. However, the corporate governance impact has been ineffectual and stock markets were also an insignificant source of funding for non-state owned firms. Finally, on a macro-level, their impact on the overall level of savings mobilization and the allocative efficiency of capital has been negligible. The policy conclusions are that, firstly, the state should begin trading the shares that it controls, and secondly, non-state owned firms should also be allowed to list.
Making and breaking power laws in evolutionary algorithm population dynamics
Deepening our understanding of the characteristics and behaviors of population-based search algorithms remains an important ongoing challenge in Evolutionary Computation. To date however, most studies of Evolutionary Algorithms have only been able to take place within tightly restricted experimental conditions. For instance, many analytical methods can only be applied to canonical algorithmic forms or can only evaluate evolution over simple test functions. Analysis of EA behavior under more complex conditions is needed to broaden our understanding of this population-based search process. This paper presents an approach to analyzing EA behavior that can be applied to a diverse range of algorithm designs and environmental conditions. The approach is based on evaluating an individualâs impact on population dynamics using metrics derived from genealogical graphs.\ud
From experiments conducted over a broad range of conditions, some important conclusions are drawn in this study. First, it is determined that very few individuals in an EA population have a significant influence on future population dynamics with the impact size fitting a power law distribution. The power law distribution indicates there is a non-negligible probability that single individuals will dominate the entire population, irrespective of population size. Two EA design features are however found to cause strong changes to this aspect of EA behavior: i) the population topology and ii) the introduction of completely new individuals. If the EA population topology has a long path length or if new (i.e. historically uncoupled) individuals are continually inserted into the population, then power law deviations are observed for large impact sizes. It is concluded that such EA designs can not be dominated by a small number of individuals and hence should theoretically be capable of exhibiting higher degrees of parallel search behavior
The Self-Organization of Interaction Networks for Nature-Inspired Optimization
Over the last decade, significant progress has been made in understanding complex biological systems, however there have been few attempts at incorporating this knowledge into nature inspired optimization algorithms. In this paper, we present a first attempt at incorporating some of the basic structural properties of complex biological systems which are believed to be necessary preconditions for system qualities such as robustness. In particular, we focus on two important conditions missing in Evolutionary Algorithm populations; a self-organized definition of locality and interaction epistasis. We demonstrate that these two features, when combined, provide algorithm behaviors not observed in the canonical Evolutionary Algorithm or in Evolutionary Algorithms with structured populations such as the Cellular Genetic Algorithm. The most noticeable change in algorithm behavior is an unprecedented capacity for sustainable coexistence of genetically distinct individuals within a single population. This capacity for sustained genetic diversity is not imposed on the population but instead emerges as a natural consequence of the dynamics of the system
Categorical Ontology of Complex Systems, Meta-Systems and Theory of Levels: The Emergence of Life, Human Consciousness and Society
Single cell interactomics in simpler organisms, as well as somatic cell interactomics in multicellular organisms, involve biomolecular interactions in complex signalling pathways that were recently represented in modular terms by quantum automata with âreversible behaviorâ representing normal cell cycling and division. Other implications of such quantum automata, modular modeling of signaling pathways and cell differentiation during development are in the fields of neural plasticity and brain development leading to quantum-weave dynamic patterns and specific molecular processes underlying extensive memory, learning, anticipation mechanisms and the emergence of human consciousness during the early brain development in children. Cell interactomics is here represented for the first time as a mixture of âclassicalâ states that determine molecular dynamics subject to Boltzmann statistics and âsteady-stateâ, metabolic (multi-stable) manifolds, together with âconfigurationâ spaces of metastable quantum states emerging from complex quantum dynamics of interacting networks of biomolecules, such as proteins and nucleic acids that are now collectively defined as quantum interactomics. On the other hand, the time dependent evolution over several generations of cancer cells --that are generally known to undergo frequent and extensive genetic mutations and, indeed, suffer genomic transformations at the chromosome level (such as extensive chromosomal aberrations found in many colon cancers)-- cannot be correctly represented in the âstandardâ terms of quantum automaton modules, as the normal somatic cells can. This significant difference at the cancer cell genomic level is therefore reflected in major changes in cancer cell interactomics often from one cancer cell âcycleâ to the next, and thus it requires substantial changes in the modeling strategies, mathematical tools and experimental designs aimed at understanding cancer mechanisms. Novel solutions to this important problem in carcinogenesis are proposed and experimental validation procedures are suggested. From a medical research and clinical standpoint, this approach has important consequences for addressing and preventing the development of cancer resistance to medical therapy in ongoing clinical trials involving stage III cancer patients, as well as improving the designs of future clinical trials for cancer treatments.\ud
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KEYWORDS: Emergence of Life and Human Consciousness;\ud
Proteomics; Artificial Intelligence; Complex Systems Dynamics; Quantum Automata models and Quantum Interactomics; quantum-weave dynamic patterns underlying human consciousness; specific molecular processes underlying extensive memory, learning, anticipation mechanisms and human consciousness; emergence of human consciousness during the early brain development in children; Cancer cell âcyclingâ; interacting networks of proteins and nucleic acids; genetic mutations and chromosomal aberrations in cancers, such as colon cancer; development of cancer resistance to therapy; ongoing clinical trials involving stage III cancer patientsâ possible improvements of the designs for future clinical trials and cancer treatments. \ud
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Use of Statistical Outlier Detection Method in Adaptive\ud Evolutionary Algorithms
In this paper, the issue of adapting probabilities for Evolutionary Algorithm (EA) search operators is revisited. A framework is devised for distinguishing between measurements of performance and the interpretation of those measurements for purposes of adaptation. Several examples of measurements and statistical interpretations are provided. Probability value adaptation is tested using an EA with 10 search operators against 10 test problems with results indicating that both the type of measurement and its statistical interpretation play significant roles in EA performance. We also find that selecting operators based on the prevalence of outliers rather than on average performance is able to provide considerable improvements to\ud
adaptive methods and soundly outperforms the non-adaptive\ud
case
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