5,484 research outputs found
Impact of motivation factors on employee retention in China: mediating role of work engagement
High employee turnover is a rising concern in China, mostly due to the growing internal job
market competition with economic betterment. This has been mostly attributed to monetary
rewards competition among companies but there is still scarce knowledge about the role nonmonetary rewards play, from a total rewards perspective. To achieve this, work engagement can
be an important explanative factor as an alternative to organizational commitment. Thus, the
purpose of this paper is to investigate how total reward components, comprehending monetary
and non-monetary rewards, influence employees’ choice to stay in Chinese organizations via
work engagement while controlling for their job satisfaction and affective organizational
commitment. With a sample of 257 employees from 19 provinces, findings show both monetary
and non-monetary are important to understand turnover intentions which was explained via the
mediator role of work engagement. Work engagement is advised to be at the central strategies
for organizations that aim to retain employees.A alta rotatividade de funcionários é uma preocupação crescente na China, principalmente devido à
crescente competição do mercado de trabalho interno com a melhoria econômica. Isso tem sido atribuído
principalmente à competição por recompensas monetárias entre as empresas, mas ainda há pouco
conhecimento sobre o papel que as recompensas não monetárias desempenham, de uma perspectiva de
recompensa total. Para tanto, o engajamento no trabalho pode ser um importante fator explicativo como
alternativa ao comprometimento organizacional. Assim, o objetivo deste artigo é investigar como os
componentes da recompensa total, compreendendo recompensas monetárias e não monetárias,
influenciam a escolha dos funcionários de permanecer nas organizações chinesas por meio do
envolvimento no trabalho, enquanto controlam sua satisfação no trabalho e compromisso organizacional
afetivo. Com uma amostra de 257 funcionários de 19 províncias, os resultados mostram que tanto
monetários como não monetários são importantes para entender as intenções de rotatividade, que foram
explicadas por meio do papel do mediador de engajamento no trabalho. O engajamento no trabalho é
apontado como uma das estratégias centrais das organizações que visam a retenção de funcionários
Development of tunable and miniature microwave filters for modern wireless communications
Due to the increasing demand for new wireless services and applications, the high level of integration and the coexistence of multi-standard (MS) or multi-band operations into a single device are becoming defining trends in designing microwave filters. This has driven considerable technological advances in reconfigurable/tunable and miniaturized filters. More specifically, reconfigurable/tunable filters that tune to different frequency bands instead of classical filter banks have great potential to significantly reduce the system size and complexity; while reducing the filter size becomes essential to achieve the highest degree of integration density in compact and portable wireless devices.
In the light of this scenario, the objective of this dissertation is to develop the new design technologies, concepts and filtering configurations for tunable microstrip filters and compact passive microwave filters. To this aim, this dissertation is divided into two main parts.
The first part (Part I) focuses on the designs of novel varactor-tuned microstrip filters with advanced performances. In this aspect, new topologies for realizing tunable lowpass and highpass filters are firstly developed. State-of-the-art performances, including wide tuning range, high selectivity with multiple transmission zeros, low insertion loss and compact size for all the tuning states are obtained in both of these filters. Secondly, two novel classes of tunable bandpass filters are presented. One of them is designed based on varactor-loaded parallel-coupled microstrip lines (PCML) and short-circuited stubs, which allows the lower passband edge together with two transmission zeros located around the lower passband skirt to be reconfigured separately. While the other tunable bandpass filter is constructed by the combination of tunable bandpass and lowpass filters, featuring both centre frequency and bandwidth tunabilities, as well as high selectivity with abundant transmission zeros. Furthermore, a new concept of tunable lossy filter is demonstrated, which attempts to achieve an equivalent high-Q tunable performance by using low-Q resonators. This concept makes the presented tunable combline filter interesting for some frequency-agile applications in which the low in-band loss variation and high selectivity are much desired while the absolute insertion loss can be a tradeoff.
The second part (Part II) is devoted to the design of miniaturized passive microwave filters with improved characteristics. For this, the concept of artificial right-handed and left-handed transmission lines are applied to the signal interference filtering topology, which results in a compact circuit size and good out-of-band performance. In particular, for a further size reduction, such filter is implemented in the forms of multilayered structure by using liquid crystal polymer (LCP) technology. Additionally, another two types of miniaturized bandpass filters using stepped impedance resonators are demonstrated, which are implemented based on different fabrication processes (i.e. LCP bonded multilayer PCB technology and a standard planar PCB technology). Among their main features, the compact size, wide passband, broad stopband with multiple transmission zeros and circuit simplicity are highlighted.
For all the proposed design techniques and filtering structures, exhaustive theoretical analyses are done, and design equations and guide rules are provided. Furthermore, all the proposed schemes and/or ideas have been experimentally validated through the design, implementation and measurement of different filters. The fabrication processes of multilayer technology utilized: liquid crystal polymer (LCP) technology and liquid crystal polymer (LCP) bonded multilayer printed circuit board (PCB) technology, are also demonstrated for reference. All of the results achieved in this dissertation make the proposed filters very attractive for their use in modern wireless communication systems
Development of turnable and miniature microwave filters for modern wireless communication
Due to the increasing demand for new wireless services and applications, the high level of integration and the coexistence of multi-standard (MS) or multi-band operations into a single device are becoming defining trends in designing microwave filters. This has driven considerable technological advances in reconfigurable/tunable and miniaturized filters. More specifically, reconfigurable/tunable filters that tune to different frequency bands instead of classical filter banks have great potential to significantly reduce the system size and complexity; while reducing the filter size becomes essential to achieve the highest degree of integration density in compact and portable wireless devices.
In the light of this scenario, the objective of this dissertation is to develop the new design technologies, concepts and filtering configurations for tunable microstrip filters and compact passive microwave filters. To this aim, this dissertation is divided into two main parts.
The first part (Part I) focuses on the designs of novel varactor-tuned microstrip filters with advanced performances. In this aspect, new topologies for realizing tunable lowpass and highpass filters are firstly developed. State-of-the-art performances, including wide tuning range, high selectivity with multiple transmission zeros, low insertion loss and compact size for all the tuning states are obtained in both of these filters. Secondly, two novel classes of tunable bandpass filters are presented. One of them is designed based on varactor-loaded parallel-coupled microstrip lines (PCML) and short-circuited stubs, which allows the lower passband edge together with two transmission zeros located around the lower passband skirt to be reconfigured separately. While the other tunable bandpass filter is
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constructed by the combination of tunable bandpass and lowpass filters, featuring both centre frequency and bandwidth tunabilities, as well as high selectivity with abundant transmission zeros. Furthermore, a new concept of tunable lossy filter is demonstrated, which attempts to achieve an equivalent high-Q tunable performance by using low-Q resonators. This concept makes the presented tunable combline filter interesting for some frequency-agile applications in which the low in-band loss variation and high selectivity are much desired while the absolute insertion loss can be a tradeoff.
The second part (Part II) is devoted to the design of miniaturized passive microwave filters with improved characteristics. For this, the concept of artificial right-handed and left-handed transmission lines are applied to the signal interference filtering topology, which results in a compact circuit size and good out-of-band performance. In particular, for a further size reduction, such filter is implemented in the forms of multilayered structure by using liquid crystal polymer (LCP) technology. Additionally, another two types of miniaturized bandpass filters using stepped impedance resonators are demonstrated, which are implemented based on different fabrication processes (i.e. LCP bonded multilayer PCB technology and a standard planar PCB technology). Among their main features, the compact size, wide passband, broad stopband with multiple transmission zeros and circuit simplicity are highlighted.
For all the proposed design techniques and filtering structures, exhaustive theoretical analyses are done, and design equations and guide rules are provided. Furthermore, all the proposed schemes and/or ideas have been experimentally validated through the design, implementation and measurement of different filters. The fabrication processes of multilayer technology utilized: liquid crystal polymer (LCP) technology and liquid crystal polymer (LCP) bonded multilayer printed circuit board (PCB) technology, are also demonstrated for reference. All of the results achieved in this dissertation make the proposed filters very attractive for their use in modern wireless communication systems.MultiWaves Project (PIRSES-GA-2010-247532) of the Seventh Framework Programme (FP7), European Commission
Properties and Origin of Galaxy Velocity Bias in the Illustris Simulation
We use the hydrodynamical galaxy formation simulations from the Illustris
suite to study the origin and properties of galaxy velocity bias, i.e., the
difference between the velocity distributions of galaxies and dark matter
inside halos. We find that galaxy velocity bias is a decreasing function of the
ratio of galaxy stellar mass to host halo mass. In general, central galaxies
are not at rest with respect to dark matter halos or the core of halos, with a
velocity dispersion above 0.04 times that of the dark matter. The central
galaxy velocity bias is found to be mostly caused by the close interactions
between the central and satellite galaxies. For satellite galaxies, the
velocity bias is related to their dynamical and tidal evolution history after
being accreted onto the host halos. It depends on the time after the accretion
and their distances from the halo centers, with massive satellites generally
moving more slowly than the dark matter. The results are in broad agreements
with those inferred from modeling small-scale redshift-space galaxy clustering
data, and the study can help improve models of redshift-space galaxy
clustering.Comment: 15 pages, 11 figures. Accepted for publication in Ap
Decentralized Stochastic Linear-Quadratic Optimal Control with Risk Constraint and Partial Observation
This paper addresses a risk-constrained decentralized stochastic
linear-quadratic optimal control problem with one remote controller and one
local controller, where the risk constraint is posed on the cumulative state
weighted variance in order to reduce the oscillation of system trajectory. In
this model, local controller can only partially observe the system state, and
sends the estimate of state to remote controller through an unreliable channel,
whereas the channel from remote controller to local controllers is perfect. For
the considered constrained optimization problem, we first punish the risk
constraint into cost function through Lagrange multiplier method, and the
resulting augmented cost function will include a quadratic mean-field term of
state. In the sequel, for any but fixed multiplier, explicit solutions to
finite-horizon and infinite-horizon mean-field decentralized linear-quadratic
problems are derived together with necessary and sufficient condition on the
mean-square stability of optimal system. Then, approach to find the optimal
Lagrange multiplier is presented based on bisection method. Finally, two
numerical examples are given to show the efficiency of the obtained results
Distributed Resource Allocation Assisted by Intercell Interference Mitigation in Downlink Multicell MC DS-CDMA Systems
This paper investigates the allocation of resources, including subcarriers and spreading codes, as well as intercell interference (ICI) mitigation for multicell downlink multicarrier direct-sequence code division multiple-access systems, which aim to maximize the system's spectral efficiency (SE). The analytical benchmark scheme for resource allocation and ICI mitigation is derived by solving or closely solving a series of mixed integer non-convex optimization problems. Based on the optimization objectives the same as the benchmark scheme, we propose a novel distributed resource allocation assisted by ICI mitigation scheme referred to as resource allocation assisted by ICI mitigation (RAIM), which requires very low implementation complexity and demands little backhaul resource. Our RAIM algorithm is a fully distributed algorithm, which consists of the subcarrier allocation (SA) algorithm named RAIM-SA, spreading code allocation (CA) algorithm called RAIM-CA and the ICI mitigation algorithm termed RAIM-IM. The advantages of the RAIM are that its CA only requires limited binary ICI information of intracell channels, and it is able to make mitigation decisions without any knowledge of ICI information. Our simulation results show that the proposed RAIM scheme, with very low complexity required, achieves significantly better SE performance than other existing schemes, and its performance is very close to that obtained by the benchmark scheme
THE EFFECTIVENESS OF A HORTICULTURE THERAPY CLASS ON PERCEIVED EMOTIONS FOR COLLEGE NURSING STUDENTS: A PRELIMINARY STUDY
poster abstractObjective: Horticultural therapy (HT) is a dynamic, guided therapeutic process that involves healthcare providers teaching patients to work with plants and natural materials. Through engaging in horticultural activities, patients achieve specific goals such as improved physical strength, memory, cognitive abilities, task initiation, language skills, and socialization. The aim of the study was to evaluate the efficacy of a horticultural therapy (HT) class for college nursing students who perceive high levels of stress in their academic and clinical nursing studies.
Method: The study was conducted at a health science university in an urban city of northern Taiwan. After explaining the procedure to and receiving consent from participants, a total of 116 college, nursing students, aged 20-39 years, mean age 26.90 (4.72), all females were recruited into the study. One group pretest and posttest design and convenient sampling were adopted. Participants received a pretest one week prior to the three-week HT class. The three-week HT class was conducted once per week with two hours for each section. Learning was evaluated with a posttest one week after the end of the HT class. Personal characteristics and outcome data was collected by a constructed questionnaire including five parts: the demographic section, the attitude towards HT, the knowledge of HT, the perceived emotional status, and the Chinese State-Trait Anxiety Inventory (C-STAI).
Results: After the three-week HT class, student-perceived emotional management and status significantly improved. While students perceived greater HT knowledge, there was no significant difference in the HT knowledge pre and post-test scores. While a decrease in anxiety was found, it failed to reach a 0.05 level of significance. It showed relationships between pretest emotional status and previous experience with the decreased level of anxiety in the results of the multiple regression analysis.
Conclusion: Engaging students in experiencing HT during an academic class could improve college nursing students' emotional status. Further refinement of the HT class and research design are suggested, such as adding a control group and involving more therapeutic activities into the class
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