In recent years, underwater acoustic wireless sensor networks have been used in many areas. There have been many field trials of acoustic propagation models and statistics for shallow water conditions. However, field ...In recent years, underwater acoustic wireless sensor networks have been used in many areas. There have been many field trials of acoustic propagation models and statistics for shallow water conditions. However, field trials are limited environmentally and, hence, not widely accepted. Simulations of the impulse response of a shallow underwater acoustic channel allows less expensive system tests that are reproducable. This paper presents a shallow water acoustic channel model based on the actual acoustic propagation characteristics with path attenuation, ambient noise, multiple paths, and Doppler effects. The second-order statistical characteristics of the simulation model are verified with the autocorrelations and crosscorrelations of the quadrature components and the complex envelopes of channel impulse responses. The channel model is implemented in Matlab with the results showing that the absorption coefficient and path losses are both dependent on the frequencies and propagation distances and that the path gain can be improved with Light of Sight （LOS） and short range acoustic propagation. Analysis of the channel impulse response and the frequency response that the zero-order Bessel function of first kind can be used to describe the correlation functions for the impulse response. The shallow underwater acoustic channel is time-varying and can not be modeled as a wide-sense stationary-uncorrelated scattering channel.展开更多
Due date quotation and scheduling are important tools to match demand with production capacity in the MTO （make-to-order） environment. We consider an order scheduling problem faced by a manufacturing f＇trm operatin...Due date quotation and scheduling are important tools to match demand with production capacity in the MTO （make-to-order） environment. We consider an order scheduling problem faced by a manufacturing f＇trm operating in an MTO environment, where the firm needs to quote a common due date for the customers, and simultaneously control the processing times of customer orders （by allocating extra resources to process the orders） so as to complete the orders before a given deadline. The objective is to minimize the total costs of earliness, tardiness, due date assignment and extra resource consumption. We show the problem is NP-hard, even if the cost weights for controlling the order processing times are identical. We identify several polynomially solvable cases of the problem, and develop a branch and bound algorithm and three Tabu search algorithms to solve the general problem. We then conduct computational experiments to evaluate the performance of the three Tabu-search algorithms and show that they are generally effective in terms of solution quality.展开更多
Neonatal asphyxia is a leading cause of neonatal death that is largely preventable with neonatal resuscitation techniques.In July 2004,China launched a 15-year,three-stage Neonatal Resuscitation Programme(NRP)with sta...Neonatal asphyxia is a leading cause of neonatal death that is largely preventable with neonatal resuscitation techniques.In July 2004,China launched a 15-year,three-stage Neonatal Resuscitation Programme(NRP)with stages in 2004–2009,2011–2016,and 2017–2021(1).The objective of China’s NRP was to ensure the presence of at least one trained attendant proficient in neonatal resuscitation at every delivery.With consistent effort,both incidence and mortality from neonatal asphyxia decreased remarkably during 2003–2020:incidence decreased from 6.32%to 1.42%and mortality decreased from 0.76‰to 0.19‰(1–2).China’s empirical experience shows that widespread promotion of high-quality neonatal resuscitation techniques can reduce preventable neonatal deaths and provide important insight into“ending preventable deaths in newborns by 2030,”as proposed in the United Nations Sustainable Development Goal’s third target(3).展开更多
What is already known about this topic?The Early Essential Newborn Care(EENC)intervention package recommended by World Health Organization(WHO)is shown to prevent and treat the leading causes of newborn illness and de...What is already known about this topic?The Early Essential Newborn Care(EENC)intervention package recommended by World Health Organization(WHO)is shown to prevent and treat the leading causes of newborn illness and death.China has begun widespread implementation of the EENC.What is added by this report?Among the 14 core interventions,including using antibiotics for mothers with premature rupture of membranes,immediate skin-to-skin contact of mother and baby,delayed umbilical cord clamping,kangaroo mother care for preterm newborn,and neonatal sepsis and pneumonia management,were not sufficiently implemented in health facilities in western China.What are the implications for public health practice?There are gaps between the implementation situation and WHO recommendations in terms of EENC capacities in western China.Targeted interventions developed accordingly can ensure quality child health care and decrease newborn mortality in China.展开更多
基金Supported by the National Natural Science Foundation of China (No. 61102110)the Cultivation Key Technology Innovation Project for Colleges and Universities Fund of Ministry of Education Project (No. 708025)+1 种基金the Technology Research and Development Program of Hebei Province (No. 10276904D)the Technology Research and Development Program of Qinhuangdao (No. 201001A061)
文摘In recent years, underwater acoustic wireless sensor networks have been used in many areas. There have been many field trials of acoustic propagation models and statistics for shallow water conditions. However, field trials are limited environmentally and, hence, not widely accepted. Simulations of the impulse response of a shallow underwater acoustic channel allows less expensive system tests that are reproducable. This paper presents a shallow water acoustic channel model based on the actual acoustic propagation characteristics with path attenuation, ambient noise, multiple paths, and Doppler effects. The second-order statistical characteristics of the simulation model are verified with the autocorrelations and crosscorrelations of the quadrature components and the complex envelopes of channel impulse responses. The channel model is implemented in Matlab with the results showing that the absorption coefficient and path losses are both dependent on the frequencies and propagation distances and that the path gain can be improved with Light of Sight （LOS） and short range acoustic propagation. Analysis of the channel impulse response and the frequency response that the zero-order Bessel function of first kind can be used to describe the correlation functions for the impulse response. The shallow underwater acoustic channel is time-varying and can not be modeled as a wide-sense stationary-uncorrelated scattering channel.
文摘Due date quotation and scheduling are important tools to match demand with production capacity in the MTO （make-to-order） environment. We consider an order scheduling problem faced by a manufacturing f＇trm operating in an MTO environment, where the firm needs to quote a common due date for the customers, and simultaneously control the processing times of customer orders （by allocating extra resources to process the orders） so as to complete the orders before a given deadline. The objective is to minimize the total costs of earliness, tardiness, due date assignment and extra resource consumption. We show the problem is NP-hard, even if the cost weights for controlling the order processing times are identical. We identify several polynomially solvable cases of the problem, and develop a branch and bound algorithm and three Tabu search algorithms to solve the general problem. We then conduct computational experiments to evaluate the performance of the three Tabu-search algorithms and show that they are generally effective in terms of solution quality.
基金Supported by the World Bank Loan Project-China Economic Transformation and Institutional Capacity Building Project(TCC6)Subproject of Experience Communication Strategy of Women and Children Health in China under the Framework of the Belt and Road Initiative(8375-CNA28-2019).
文摘Neonatal asphyxia is a leading cause of neonatal death that is largely preventable with neonatal resuscitation techniques.In July 2004,China launched a 15-year,three-stage Neonatal Resuscitation Programme(NRP)with stages in 2004–2009,2011–2016,and 2017–2021(1).The objective of China’s NRP was to ensure the presence of at least one trained attendant proficient in neonatal resuscitation at every delivery.With consistent effort,both incidence and mortality from neonatal asphyxia decreased remarkably during 2003–2020:incidence decreased from 6.32%to 1.42%and mortality decreased from 0.76‰to 0.19‰(1–2).China’s empirical experience shows that widespread promotion of high-quality neonatal resuscitation techniques can reduce preventable neonatal deaths and provide important insight into“ending preventable deaths in newborns by 2030,”as proposed in the United Nations Sustainable Development Goal’s third target(3).
文摘What is already known about this topic?The Early Essential Newborn Care(EENC)intervention package recommended by World Health Organization(WHO)is shown to prevent and treat the leading causes of newborn illness and death.China has begun widespread implementation of the EENC.What is added by this report?Among the 14 core interventions,including using antibiotics for mothers with premature rupture of membranes,immediate skin-to-skin contact of mother and baby,delayed umbilical cord clamping,kangaroo mother care for preterm newborn,and neonatal sepsis and pneumonia management,were not sufficiently implemented in health facilities in western China.What are the implications for public health practice?There are gaps between the implementation situation and WHO recommendations in terms of EENC capacities in western China.Targeted interventions developed accordingly can ensure quality child health care and decrease newborn mortality in China.
