Showing papers by "University of Macau published in 2006"

Today's state‐owned enterprises of China: are they dying dinosaurs or dynamic dynamos?

Abstract: This paper raises the question and provides empirical evidence regarding the status of the evolution of the state-owned enterprises (SOEs) in China today. In this study, we compare the SOEs to domestic private-owned enterprises (POEs) and foreign-controlled businesses (FCBs) in the context of their organizational cultures. While a new ownership form, many of the POEs evolved from former collectives that reflect the traditional values of Chinese business. Conversely, the FCBs are much more indicative of the large global MNCs. Therefore, we look at the SOEs in the context of these two reference points. We conclude that the SOEs of today have substantially transformed to approximate a configuration desired by the Chinese government when it began the SOE transformation a couple of decades ago to make them globally competitive. The SOEs of today appear to be appropriately described as China's economic dynamic dynamo for the future. Copyright © 2006 John Wiley & Sons, Ltd.

Miniaturized microstrip lowpass filter with wide stopband using double equilateral U-shaped defected ground structure

Abstract: A compact double equilateral U-shaped defected ground structure (DGS) unit is proposed. In contrast to a single finite attenuation pole characteristic offered by the conventional dumbbell DGS, the proposed DGS unit provides dual finite attenuation poles that can be independently controlled by the DGS lengths. A 2.4-GHz microstrip lowpass filter using five cascaded double U-shaped DGS units is designed and compared with conventional DGS lowpass filters. This low pass filter achieves a wide stopband with overall 30-dB attenuation up-to10 GHz and more than 42% size diminution.

Efficient model updating and health monitoring methodology using incomplete modal data without mode matching

Abstract: A methodology is presented for Bayesian structural model updating using noisy incomplete modal data corresponding to natural frequencies and partial mode shapes of some of the modes of a structural system. The procedure can be used to find the most probable model within a specified class of structural models, based on the incomplete modal data, as well as the most probable values of the system natural frequencies and the full system mode shapes. The method does not require matching measured modes with corresponding modes from the structural model, which is in contrast to many existing methods. To find the most probable values of the structural model parameters and system modal parameters, the method uses an iterative scheme involving a series of coupled linear optimization problems. Furthermore, it does not require solving the eigenvalue problem of any structural model; instead, the eigenvalue equations appear in the prior probability distribution to provide soft constraints. The method appears to be computationally efficient and robust, judging from its successful application to noisy simulated data for a ten-storey building model and for a three-dimensional braced-frame model. This latter example is also used to demonstrate an application to structural health monitoring.

Kinematic analysis and design of a new 3-DOF translational parallel manipulator

Abstract: A new three degrees of freedom (3-DOF) translational parallel manipulator (TPM) with fixed actuators called a 3-PRC TPM is proposed in this paper. The mobility of the manipulator is analyzed via screw theory. The inverse kinematics, forward kinematics, and velocity analysis are performed and the singular and isotropic configurations are identified afterward. Moreover, the mechanism design to eliminate all singularities and generate an isotropic manipulator has been presented. With the variation on architectural parameters, the reachable workspace of the manipulator is generated and compared. Especially, it is illustrated that the manipulator in principle possesses a uniform workspace with a constant hexagon shape cross section. Furthermore, the dexterity characteristics are investigated in the local and global sense, respectively, and some considerations for real machine design have been proposed as well. DOI: 10.1115/1.2198254

Transferring organizational learning systems to Japanese subsidiaries in China

Abstract: Qualitative interviews and observations were conducted to study the cross-border transfer of organizational learning systems to the subsidiaries of five Japanese manufacturing companies operating in South China. This paper develops a holistic model of the overall process, by integrating knowledge-oriented, routine-oriented, and social/contextual perspectives, each of which plays a necessary role in explaining essential aspects. One feature of the transfer of organizational learning systems entailed arranging local access to, and opportunity to replicate, various types of knowledge repository that contained corporate values as well as technical expertise. A second feature involved the development of collective learning routines through dynamic interplay with evolving, locally based, knowledge repositories. A third feature, in two companies, entailed the creation of enterprise contexts that reproduced the socialization and corporate culture maintenance rituals, and the open plan factory and office designs, that were hallmarks of the respective parent companies, and which appeared highly conducive to the transfer of collective learning routines to the local sites. Findings indicate that successful cross-border transfer of organizational learning systems entails the development and implementation of an overall heuristic design for cultivating collective learning routines through the engineering of enterprise contexts and the responsive management of knowledge repositories.

Application of a three-level NPC inverter as a three-phase four-wire power quality compensator by generalized 3DSVM

Abstract: A two-level four-leg inverter has been developed for the three-phase four-wire power quality compensators. When it is applied to medium and large capacity compensators, the voltage stress across each switch is so high that the corresponding dv/dt causes large electromagnetic interference. The multilevel voltage source inverter topologies are good substitutes, since they can reduce voltage stress and improves output harmonic contents. The existing three-level neutral point clamped (NPC) inverter in three-phase three-wire systems can be used in three-phase four-wire systems also, because the split dc capacitors provide a neutral connection. This paper presents a comparison study between the three-level four-leg NPC inverter and the three-level NPC inverter. A fast and generalized applicable three-dimensional space vector modulation (3DSVM) is proposed for controlling a three-level NPC inverter in a three-phase four-wire system. The zero-sequence component of each vector is considered in order to implement the neutral current compensation. Both simulation and experimental results are given to show the effectiveness of the proposed 3DSVM control strategy. Comparisons between the 3DSVM and the 3-D hysteresis control strategy are also achieved.

Structural Health Monitoring via Measured Ritz Vectors Utilizing Artificial Neural Networks

Abstract: A pattern recognition approach for structural health monitoring (SHM) is presented that uses damage-induced changes in Ritz vectors as the features to characterize the damage patterns defined by the corresponding locations and severity of damage. Unlike most other pattern recognition methods, an artificial neural network (ANN) technique is employed as a tool for systematically identifying the damage pattern corresponding to an observed feature. An important aspect of using an ANN is its design but this is usually skipped in the literature on ANN-based SHM. The design of an ANN has significant effects on both the training and performance of the ANN. As the multi-layer perceptron ANN model is adopted in this work, ANN design refers to the selection of the number of hidden layers and the number of neurons in each hidden layer. A design method based on a Bayesian probabilistic approach for model selection is proposed. The combination of the pattern recognition method and the Bayesian ANN design method forms a practical SHM methodology. A truss model is employed to demonstrate the proposed methodology.

A novel design and analysis of a 2-DOF compliant parallel micromanipulator for nanomanipulation

Abstract: A new 2-degrees of freedom compliant parallel micromanipulator (CPM) utilizing flexure joints is proposed for two-dimensional nanomanipulation in this paper. By a proper selection of actuators, flexure hinges, and materials, this system is constructed and analyzed by a pseudorigid-body model, architectural optimization, and finite-element analysis. Both the position and velocity kinematic modelings are established, and afterwards, statics analysis is performed. In view of the physical constraints imposed by pizeo-actuators and flexure hinges, the CPM's workspace area is determined. And in order to achieve a maximum workspace subjected to the given dexterity indices, kinematic optimization of the design parameters is carried out, which results in a manipulator satisfying the operational requirements. Furthermore, the finite-element analysis has been undertaken to validate the analytical modeling, and the influence of architectural parameters on CPM performance has been evaluated as well. Note to Practitioners-This paper is motivated by the problem of designing a nanomanipulator for two-dimensional (2-D) assembly of nanoscale objects via nanomanipulation. A novel planar parallel mechanism incorporating compliant mechanisms is designed for such a purpose. Since the application of the manipulator depends significantly on the kinematic mathematical models, the designed compliant parallel micromanipulator (CPM) is analyzed by the established pseudorigid-body (PRB) model. The architectural optimization leads to a CPM satisfying the workspace and resolution requirements of this work. Moreover, finite-element analysis is performed to verify the accuracy of the developed PRB model, and simulation results illustrate the efficiency of the PRB model in designing and analyzing the CPM. Since the designed CPM is composed solely of flexural elements which are known to be competent in high precise applications, it is reasonable to expect that the CPM could find its way into 2-D manipulation of nanoscale components.

rCOS: a refinement calculus of object systems

Abstract: This article presents a mathematical characterization of object-oriented concepts by defining an observation-oriented semantics for a relational object-based language with a rich variety of features including subtypes, visibility, inheritance, type casting, dynamic binding and polymorphism. The language can be used to specify object-oriented designs as well as programs. We present a calculus that supports both structural and behavioural refinement of object-oriented designs. The design calculus is based on the predicate logic in Hoare and He's Unifying Theories of Programming (UTP).

Substructure Identification and Health Monitoring Using Noisy Response Measurements Only

Abstract: A probabilistic substructure identification and health monitoring methodology for linear systems is presented using measured response time histories only. A very large number of uncertain parameters have to be identified if one considers the updating of the entire structure. For identifiability, one then would require a very large number of sensors. Furthermore, even when such a large number of sensors are available, process- ing of vast amount of the corresponding data raises com- putational difficulties. In this article a substructuring ap- proach is proposed, which allows for the identification and monitoring of some critical substructures only. The proposed method does not require any interface measure- ments and/or excitation measurements. No information regarding the stochastic model of the input is required. Specifically, the method does not require the response to be stationary and does not assume any knowledge of the parametric form of the spectral density of the input. There- fore, the method has very wide applicability. The proposed approach allows one to obtain not only the most probable values of the updated model parameters but also their as- sociated uncertainties using only one set of response data. The probability of damage can be computed directly using data from the undamaged and possibly damaged struc- ture. A hundred-story building model is used to illustrate the proposed method.

A Markov Chain Model for the Adaptive CUSUM Control Chart

Abstract: When the magnitude of a future shift is unknown, a control chart designed to perform over a range of shifts is a better option than optimizing the performance at detecting a certain level of shifts. In this sense, the adaptive cumulative sum (ACUSUM) ch..

Getting bank financing: A study of Vietnamese private firms

Abstract: Private firms in transition economies are operating in an extremely uncertain environment, with underdeveloped market institutions, poorly defined property rights, and absence of reliable business data. This raises a very basic question of how owners of these firms persuade bankers to make much needed loans. This study employs an institutional perspective and argues that firms' legitimacy positively influences their accessibility to bank financing. Specifically, this study develops a model that links networking, professional management practices, and growth stage with bank financing and tests that model using a sample of Vietnamese private firms. The results support the hypotheses that growth stage and networking greatly influence firms' accessibility to bank financing, and that the impact of networking on financing is contingent on the growth stage.

Towards a Model for Teacher Professional Development in China: Introducing Keli

Abstract: This paper describes Keli (Exemplary Lesson Development), a new model of in-service teacher education in China, implemented within a broader program of Xingdong Jiaoyu (Action Education), which has been implemented since 2003. This paper sets out how to implement the innovative Keli model. Finally, the implications for the practical community, including teachers and researchers, are examined.

Transitional Heat Transfer in Plain Horizontal Tubes

Abstract: In this study, the heat transfer behavior in the transition region for plain horizontal tubes under a uniform wall heat flux boundary condition is discussed in detail. In particular, the influence of inlet configuration and free convection superimposed on the forced convection (or mixed convection) at the start and end of the transition region and the magnitude of heat transfer are addressed. The available correlations to predict the heat transfer coefficient in the transition region are reviewed, and their performance are evaluated based on 1290 experimental data points obtained under a wide range of experimental conditions. Appropriate correlations for the mixed and forced convection transition regions are recommended. Finally, a flow regime map for determination of the boundary between forced and mixed convection in horizontal tubes with different inlets is presented.

Smooth Path Planning of a Mobile Robot Using Stochastic Particle Swarm Optimization

Abstract: This paper proposes a new approach using improved particle swarm optimization (PSO) to optimize the path of a mobile robot through an environment containing static obstacles. Relative to many optimization methods that produce nonsmooth paths, the PSO method developed in this paper can generate smooth paths, which are more preferable for designing continuous control technologies to realize path following using mobile robots. To reduce computational cost of optimization, the stochastic PSO (S-PSO) with high exploration ability is developed, so that a swarm with small size can accomplish path planning. Simulation results validate the proposed algorithm in a mobile robot path planning.

Trust and Uncertainty: A Study of Bank Lending to Private SMEs in Vietnam

Abstract: This research explores the question of how – in the absence of institutions that legitimate markets, contracts, and private property, and the lack of business data – banks make loan decisions to th...

Optimization of free ammonia concentration for nitrite accumulation in shortcut biological nitrogen removal process.

Abstract: A shortcut biological nitrogen removal (SBNR) utilizes the concept of a direct conversion of ammonium to nitrite and then to nitrogen gas. A successful SBNR requires accumulation of nitrite in the system and inhibition of the activity of nitrite oxidizers. A high concentration of free ammonia (FA) inhibits nitrite oxidizers, but unfortunately decreases the ammonium removal rate as well. Therefore, the optimal range of FA concentration is necessary not only to stabilize nitrite accumulation but also to achieve maximum ammonium removal. In order to derive such optimal FA concentrations, the specific substrate utilization rates of ammonium and nitrite oxidizers were measured. The optimal FA concentration range appeared to be 5-10 mg/L for the adapted sludge. The simulated results from the modified inhibition model expressed by FA and ammonium/nitrite concentrations were shown very similar to the experimental results.