Application of a transversal laguerre network in adaptive equalization     

K.M. Wong  Y.G. Jan  F.C. Lee 《Journal of The Franklin Institute》1984,317(2):105-115

Synchronous data transmission systems that transmit information over dispersive channels often employ adaptive equalization techniques in the processing of the received signals. Most equalizers presently used in communication systems are of the tapped delay line (TDL) type. In this paper, we propose a class of adaptive equalizers of which the TDL equalizer is a member. Another interesting member of this class is the Laguerre adaptive equalizer which is to be introduced in this paper. The configuration of the Laguerre equalizer is developed. It is found, as shown by the examples, that the Laguerre equalizer is more accurate, and is less sensitive to timing error than the conventional TDL equalizer.  相似文献   

Robust estimator design with an emphasis balance between performance and robustness     

Hyeon-Cheol Lee  Don R. Halverson 《Journal of The Franklin Institute》2007,344(7):954-968

From a number of ML estimators (typically unbiased) of practical interest which include the variance for a Gaussian distribution, the standard deviation for a Laplace distribution, the variance for a Rayleigh distribution and a “spread parameter” for a Cauchy distribution, we design robust estimators according to an emphasis balance between normalized performance and normalized robustness. We measure performance with inverted MSE and robustness with a differential geometric approach.  相似文献   

Negotiating for change: women’s movements and education reform in Taiwan     

Shu‐Ching Lee 《Gender and education》2011,23(1):47-58

The dramatic changes during the past 20 years in Taiwan offer a good example of how gender policy in education is facilitated by a combination of interrelated economic, political and social forces. Taiwan’s policy on gender education emerged from the interaction of state, education, academic and non‐academic feminist positions in reforms. This paper demonstrates – first, the importance of the socio‐political contexts in which reform was proposed, and second, the actions of feminists in making best use of the opportunities thrown up by a confluence of social factors. The social, economic and political transformations of the 1980s saw the rise of a ‘new’ state both supposedly and in reality more responsive to the needs of non‐profit organisations. In testing out relationships of partnership with the state, feminist activists saw the deregulation of education as an opportunity to get women’s issues on the agenda. These reforms were catalysed by a series of social events bringing together supporters in a mood of celebration, protest or mourning specifically in response to particular events. The struggles, contentions, and negotiations that underlay the eventual approval of gender reform in education are illustrated.  相似文献   

Immigrant girls as caregivers to younger siblings: a transnational feminist analysis     

Jo‐Anne Lee 《Gender and education》2011,23(2):105-119

This article employs a transnational feminist lens to examine the experiences of racialised immigrant girls who provide care for their younger siblings. The article draws on findings from a participatory action research study in Victoria, British Columbia, Canada to examine the role that immigrant girls’ caregiving practices play in transnational families’ social, economic, and cultural survival. It argues that greater attention should be given to the diverse and complex contexts, consequences, costs, and contributions of immigrant girls’ caregiving labour.  相似文献   

A new age for child protection--General Comment 13: why it is important, how it was constructed, and what it intends?     

Hart SN  Lee Y  Wernham M 《Child abuse & neglect》2011,35(12):970-978

Children continue to be subjected to high levels of violence (i.e., physical, psychological and sexual maltreatment) throughout the world. International concern about violence against children has increased significantly during the last decade. A Study on Violence Against Children, encouraged by the UN Committee on the Rights of the Child, conducted under the auspices of the United Nations Secretary General and reported in 2006, has become a rallying call to improve child protection. Child protection practices and systems have been judged to be generally inadequate and, in some cases, destructive. It is widely recognized that business as usual—more of the same—will not do. A General Comment (guide to fulfilling obligations) for Article 19, the central conceptualization of child protection of the UN Convention on the Rights of the Child, has the potential to promote a worldwide reformulation of child protection priorities, policies, and practices by virtue of the infusion of a child rights approach. It can be a mechanism for framing and promoting the transformational change needed – for a genuine paradigm shift. Here, explication is given for the historical context, rationale, centrality of child rights, process of development, holistic nature, and primary elements of General Comment 13 (GC13): The child's right to freedom from all forms of violence. GC13 embodies and champions a child rights approach to child protection entailing strong support for proactive primary prevention, promotion of good child care, and a commitment to secure the rights and well-being of all children. A child rights-based, comprehensive coordinating framework is recommended for the implementation of GC13.  相似文献   

Identifying and predicting problem behavior trajectories among pre-school children investigated for child abuse and neglect     

Woodruff K  Lee B 《Child abuse & neglect》2011,35(7):491-503

Objective

Young children involved with child welfare services are at high risk for behavior problems. This study aims to identify externalizing behavior paths that preschoolers in this high-risk population follow over a 6 year period, and the predictors of membership in normative and problematic pathways.

Methods

Using data from the National Study of Child and Adolescent Well-being (NSCAW), the sample included 246 4-year-olds who remained home after investigation. Latent class growth analysis (LCGA) was used to estimate the number, size, and shape of subgroups of preschoolers following distinct behavioral pathways. Early predictors of membership in the resulting groups were then examined.

Results

Four groups of preschool children following distinct behavior trajectories over 6 years were identified. Weighted results show that more than half (61%) of the children followed a low/normal problem behavior trajectory while just over one tenth (12%) were on a persistent high trajectory, remaining in the clinical range throughout the study. Improving (23%) and worsening (4%) problem behavior groups were also identified. Internalizing problems, attention problems, child ethnicity, and maltreatment type reported at age 4 predicted membership in the trajectory groups.

Conclusions

Internalizing behavior problems and maltreatment type may distinguish preschool children who are more likely to experience worsening or persistent problematic externalizing behaviors from those likely to follow a normal behavior trajectory.

Practice implications

Identifying early indicators of externalizing behavior problems and addressing them with evidence-based interventions to reduce negative behaviors may avert long-term negative outcomes.  相似文献   

Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers     

Lee BR  Lee KH  Kang E  Kim DS  Lee SH 《Biomicrofluidics》2011,5(2):22208

The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.  相似文献   

Stem cells in microfluidics     

Wu HW  Lin CC  Lee GB 《Biomicrofluidics》2011,5(1):13401

Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research.  相似文献   

On-demand electrostatic droplet charging and sorting     

Ahn B  Lee K  Panchapakesan R  Oh KW 《Biomicrofluidics》2011,5(2):24113

This study reports a droplet-based microfluidic device for on-demand electrostatic droplet charging and sorting. This device combines two independent modules: one is a hydrodynamic flow focusing structure to generate water-in-oil droplets, and the other is the two paired-electrodes for charging and sorting of the droplets. Depending on the polarity on charging electrodes, water-in-oil droplets can be electrostatically charged positively or negatively, followed by automatic real-time electric sorting. This approach will be useful when preformed droplets, with a positive, a negative, or with no charge, need to be manipulated for further on-chip droplet manipulation.  相似文献   

Bromo-oxidation reaction in enzyme-entrapped alginate hollow microfibers     

Asthana A  Lee KH  Shin SJ  Perumal J  Butler L  Lee SH  Kim DP 《Biomicrofluidics》2011,5(2):24117

In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure.  相似文献