Controlling Chaos in a Neural Network Based on the Phase Space Constraint

The chaotic neural network constructed with chaotic neurons exhibits very rich dynamic behaviors and has a nonperiodic associative memory. In the chaotic neural network, however, it is dicult to distinguish the stored patters from others, because the states of output of the network are in chaos. In order to apply the nonperiodic associative memory into information search and pattern identication, etc, it is necessary to control chaos in this chaotic neural network. In this paper, the phase space constraint method focused on the chaotic neural network is proposed. By analyzing the orbital of the network in phase space, we chose a part of states to be disturbed. In this way, the evolutional spaces of the strange attractors are constrained. The computer simulation proves that the chaos in the chaotic neural network can be controlled with above method and the network can converge in one of its stored patterns or their reverses which has the smallest Hamming distance with the initial state of the network. The work claries the application prospect of the associative dynamics of the chaotic neural network

A Type of Delay Feedback Control of Chaotic Dynamics in a Chaotic Neural Network

A chaotic neural network consisting of chaotic neurons exhibits such rich dynamical behaviors as nonperiodic associative memory. But it is difficult to distinguish the stored patterns from others, since the chaotic neural network shows chaotic wandering around the stored patterns. In order to apply the nonperiodic associative memory to information search or pattern identification, it is necessary to control chaotic dynamics. In this paper, we propose a delay feedback control method for the chaotic neural network. Computer simulation shows that, by means of the control method, the chaotic dynamics in the chaotic neural network are changed. The output sequence of the controlled network wanders around one stored pattern and its reverse pattern

Hydrocarbon emissions from a modern commercial airliner

We report selected carbon species emission indices (EIs) for a Rolls Royce RB211-535-E4 turbofan engine that were acquired during the NASA EXperiment to Characterize Aircraft Volatile Aerosol and Trace-species Emissions (EXCAVATE). Conducted during winter 2002, the mission focused upon characterizing the exhaust constituents of the NASA Boeing 757 aircraft during ground-based operation. Carbon species concentrations were determined by chromatographic analyses of whole air samples collected 10 m behind the engine exit plane as engine power was varied from ground idle to about 60% of maximum rated thrust. Ambient air samples were also collected and analyzed to facilitate correction of calculated EIs for background concentrations. Results are consistent with previous observations and indicate that, on a relative basis, turbine engines emit considerable amounts of light hydrocarbon species at idle, but significantly lesser amounts at higher engine powers. © 2005 Elsevier Ltd. All rights reserved

Implications of the recent fluctuations in the growth rate of tropospheric methane

Global measurements show that the mixing ratio of tropospheric methane (CH4) increased by 1.1% (19.5 ± 1.7 ppbv) over the five-year period 1996-2000, with striking fluctuations in its annual growth rate. Whereas the global CH4 growth rate reached 15.9 ± 0.7 ppbv yr-1 in 1998, the growth rate was -2.1 ± 0.8 ppbv yr-1 in 2000. This is the first time in our 23-year global monitoring program that we have measured a negative annual CH4 growth rate. The CH4 growth rate fluctuates in an unpredictable fashion, and we reemphasize that global CH4 concentrations cannot be extrapolated into the future based on past trends. As a result, we suggest that the slowing of the CH4 growth rate during much of the 1980s and 1990s cannot be used to imply that CH4 will no longer be of concern in greenhouse gas studies during this century

Estimation of global vehicular methyl bromide emissions: Extrapolation from a case study in Santiago, Chile

Between June 1 and June 8, 1996, 144 whole air samples were collected in Santiago, Chile. The temporal and geographical enhancement of CH3Br correlated with incomplete combustion tracers emitted from vehicles during the morning commute. From these, a city-wide CH3Br/CO volume emission ratio of 2.2 × 10-6 was measured in ambient air. Without using the CO measurements, we estimate an annual release of 8.9 tons of CH3Br in Santiago based solely upon enhanced concentrations observed throughout the study area during the morning traffic period. This enhancement corresponds to 8.0 × 10-6 kg CH3Br emitted for each liter of gasoline used (leaded and unleaded). By scaling the annual gasoline usage in Santiago to countries still using leaded gasoline, and assuming the above 8.0 × 10-6 kg/L value holds true, a global vehicular CH3Br emission of 4 ± 3 Gg/year is calculated. This small vehicular CH3Br emission source strength will not improve the current CH3Br budget imbalance

Influence of convection and biomass burning outflow on tropospheric chemistry over the tropical Pacific

Observations over the tropics from the Pacific Exploratory Mission-Tropics A Experiment are analyzed using a one-dimensional model with an explicit formulation for convective transport. Adopting tropical convective mass fluxes from a general circulation model (GCM) yields a large discrepancy between observed and simulated CH3I concentrations. Observations of CH3I imply the convective mass outflux to be more evenly distributed with altitude over the tropical ocean than suggested by the GCM. We find that using a uniform convective turnover lifetime of 20 days in the upper and middle troposphere enables the model to reproduce CH3I observations. The model reproduces observed concentrations of H2O2 and CH3OOH. Convective transport of CH3OOH from the lower troposphere is estimated to account for 40-80% of CH3OOH concentrations in the upper troposphere. Photolysis of CH3OOH transported by convection more than doubles the primary HOx source and increases OH concentrations and O3 production by 10-50% and 0.4 ppbv d-1, respectively, above 11 km. Its effect on the OH concentration and O3 production integrated over the tropospheric column is, however, small. The effects of pollutant import from biomass burning regions are much more dominant. Using C2H2 as a tracer, we estimate that biomass burning outflow enhances O3 concentrations, O3 production, and concentrations of NOx and OH by 60%, 45%, 75%, and 7%, respectively. The model overestimates HNO3 concentrations by about a factor of 2 above 4 km for the upper one-third quantile of C2H2 data while it generally reproduces HNO3 concentrations for the lower and middle one-third quantiles of C2H2 data. Copyright 2000 by the American Geophysical Union

Strengthening Immigration Support for Agricultural Labor Migration and Ending Modern Day “Harvest of Shame” A Comparative Study of the American and Australian Approaches

Both the United States and Australia rely extensively on migrant farmworkers, specifically those without lawful working permits, to meet their labor demands. This excessive dependence sparks debate over the effectiveness of immigration policies in safeguarding access to, and the sustainability of, the agricultural workforce. It also raises human rights concerns as migrant farmworkers often face a myriad of dangers and injustices on the job. In particular, undocumented farmworkers remain largely marginalized and exploited, but they are not entitled to full rights under the law, and they are reluctant to speak up against abusive labor practices due to their immigration status and the fear of detention and deportation.
 This Article aims to identify feasible immigration solutions for the United States and Australia to strengthen their short-term and long-term agricultural workforce, and to uphold migrant farmworkers' rights. Part II of the Article reveals migrant farmworkers' silent struggle and discusses the importance of agricultural labor reform. Part III and Part IV compare the two immigration systems and their respective responses to the workforce and human rights issues associated with the use of migrant farmworkers. The comparison primarily focuses on the H-2A visa program and the 2021 agricultural labor bill in the United States, as well as the temporary visa schemes and the amnesty proposal in Australia. The Article acknowledges the merits of the two immigration systems, but argues that weaknesses prevail in some aspects. The United States and Australia should look at each other's practices and re-align their immigration policies so that they both create effective immigration systems that ensure the short-term and long-term agricultural workforce, and protect migrant farmworkers' human rights. A brief conclusion re-emphasizes the importance of agricultural labor reform and highlights remaining concerns regarding the reform

“So Teacher, What is the Right Answer?” Incorporating Critical Thinking into the Mexican Legal Education: The Application of the US Model

Over the past few decades, the Mexican government has made some commitments to improving the rule of law. Meanwhile, many foreign government agencies, non-governmental organizations (NGOs), and private donors, mainly from the United States (U.S.), have also provided tremendous support to help Mexico reform its justice system. Despite these efforts, corruption, injustice, and impunity are still the everyday realities and fixing Mexico's broken rule of law remains an uphill battle. From a technical perspective, it is not easy to develop a comprehensive package of "ambitious legislative changes and constitutional amendments" as well as an effective implementation mechanism. From a financial perspective, adhering to the rule of law does not come cheap; it is inevitable that a substantial budget for reform-associated costs is needed. In addition, there are major obstacles. For instance, one major obstacle to building the rule of law in Mexico is the ruling class' resistance to being ruled by the law for fear of losing their power and privileges.5 A strong political will to implement change is crucial to driving any meaningful reforms in the justice sector. Numerous studies have been conducted with respect to the approaches that Mexico could take to overcome the technical and financial challenges. However, the political will to reform appears to be a less-discussed topic