Showing papers by "Nanyang Technological University published in 2000"

Tunneling or Value Addition? Evidence from Mergers by Korean Business Groups

Abstract: Business groups in emerging markets have the potential to create either value or agency problems. Using Korean mergers, we investigate the nature of business groups in emerging markets and examine whether Korean business groups (chaebols) add value to their member firms or provide the controlling shareholders with an opportunity for wealth transfer (tunneling). We show that chaebol-affiliated firms that performed well prior to the merger realize significantly negative announcement returns. We also find that chaebol bidders who acquired poorly performing targets within the same group and/or had concentrated equity ownership by owner-managers experience significantly negative abnormal returns. These types of mergers, however, have a significantly positive effect on the market value of the portfolio of other firms in the group. Our results support the tunneling view that firms belonging to business groups pay less attention to the maximization of individual firm value and make takeover decisions that are beneficial to only controlling shareholders.

Tensile properties of short-glass-fiber- and short-carbon-fiber-reinforced polypropylene composites

Abstract: Composites of polypropylene (PP) reinforced with short glass fibers (SGF) and short carbon fibers (SCF) were prepared with extrusion compounding and injection molding techniques. The tensile properties of these composites were investigated. It was noted that an increase in fiber volume fraction led to a decrease in mean fiber length as observed previously. The relationship between mean fiber length and fiber volume fraction was described by a proper exponential function with an offset. The tensile strength and modulus of SGF/PP and SCF/PP composites were studied taking into account the combined effect of fiber volume fraction and mean fiber length. The results about the composite strength and modulus were interpreted using the modified rule of mixtures equations by introducing two fiber efficiency factors, respectively, for the composite strength and modulus. It was found that for both types of composites the fiber efficiency factors decreased with increasing fiber volume fraction and the more brittle fiber namely carbon fiber corresponded to the lower fiber efficiency factors than glass fiber. Meanwhile, it was noted that the fiber efficiency factor for the composite modulus was much higher than that for the composite strength. Moreover, it was observed that the tensile failure strain of the composites decreased with the increase of fiber volume fraction. An empirical but good relationship of the composite failure strain with fiber volume fraction, fiber length and fiber radius was established.

The paradox of low body mass index and high body fat percentage among Chinese, Malays and Indians in Singapore

Abstract: Objective To study the relationship between body fat percentage and body mass index (BMI) in three different ethnic groups in Singapore (Chinese, Malays and Indians) in order to evaluate the validity of the BMI cut-off points for obesity. Design Cross-sectional study. Subjects Two-hundred and ninety-one subjects, purposively selected to ensure adequate representation of range of age and BMI of the general adult population, with almost equal numbers from each ethnic and gender group. Measurements Body weight, body height, sitting height, wrist and femoral widths, skinfold thicknesses, total body water by deuterium oxide dilution, densitometry with Bodpod(R) and bone mineral content with Hologic(R) QDR-4500. Body fat percentage was calculated using a four-compartment model. Results Compared with body fat percentage (BF%) obtained using the reference method, BF% for the Singaporean Chinese, Malays and Indians were under-predicted by BMI, sex and age when an equation developed in a Caucasian population was used. The mean prediction error ranged from 2.7% to 5.6% body fat. The BMI/BF% relationship was also different among the three Singaporean groups, with Indians having the highest BF% and Chinese the lowest for the same BMI. These differences could be ascribed to differences in body build. It was also found that for the same amount of body fat as Caucasians who have a body mass index (BMI) of 30 kg/m2 (cut-off for obesity as defined by WHO), the BMI cut-off points for obesity would have to be about 27 kg/m2 for Chinese and Malays and 26 kg/m2 for Indians. Conclusions The results show that the relationship between BF% and BMI is different between Singaporeans and Caucasians and also among the three ethnic groups in Singapore. If obesity is regarded as an excess of body fat and not as an excess of weight (increased BMI), the cut-off points for obesity in Singapore based on the BMI would need to be lowered. This would have immense public health implications in terms of policy related to obesity prevention and management.

Face recognition by support vector machines

Abstract: Support vector machines (SVM) have been recently proposed as a new technique for pattern recognition. SVM with a binary tree recognition strategy are used to tackle the face recognition problem. We illustrate the potential of SVM on the Cambridge ORL face database, which consists of 400 images of 40 individuals, containing quite a high degree of variability in expression, pose, and facial details. We also present the recognition experiment on a larger face database of 1079 images of 137 individuals. We compare the SVM-based recognition with the standard eigenface approach using the nearest center classification (NCC) criterion.

Fingerprint minutiae matching based on the local and global structures

Abstract: Proposes a fingerprint minutia matching technique, which matches the fingerprint minutiae by using both the local and global structures of minutiae. The local structure of a minutia describes a rotation and translation invariant feature of the minutia in its neighborhood. It is used to find the correspondence of two minutiae sets and increase the reliability of the global matching. The global structure of minutiae reliably determines the uniqueness of fingerprint. Therefore, the local and global structures of minutiae together provide a solid basis for reliable and robust minutiae matching. The proposed minutiae matching scheme is suitable for an online processing due to its high processing speed. Experimental results show the performance of the proposed technique.

Language Learning Strategy Use of Bilingual Foreign Language Learners in Singapore

Abstract: This study, using Oxford's 80-item Strategy Inventory for Language Learning (SILL), examines the self-reported language learning strategy use of 678 university students learning Japanese and French as foreign languages in Singapore. The study differs from previous SILL studies in that the participants were bilingual from a multicultural setting, and the use of all 80 strategies was examined. Relationships between background variables and overall strategyuse were investigated using ANOVA. Results were significant for motivation, self-rated proficiency, and language studied, with motivation significantly interacting with language studied. The use of each strategy by proficiency and also by gender was investigated using chi-square. Results showed more learning strategy use among learners with higher proficiency and, unexpectedly, more strategies used significantly more often by men.

Efficiency and risk in Japanese banking

Abstract: This paper investigates the impact of risk and quality factors on banks’ cost by using the stochastic cost frontier methodology to evaluate scale and X-inefficiencies, as well as technical change for a sample of Japanese commercial banks between 1993 and 1996. Loan-loss provisions are included in the cost frontier model to control for output quality, with a financial capital and a liquidity ratio included to control risk. Following the approach suggested in Mester (1996) we show that if risk and quality factors are not taken into account optimal bank size tends to be overstated. That is, optimal bank size is considerably smaller when risk and quality factors are taken into account when modelling the cost characteristics of Japanese banks. We also find that the level of financial capital has the biggest influence on the scale efficiency estimates. X-inefficiency estimates, in contrast, appear less sensitive to risk and quality factors. Our results also suggest that scale inefficiencies dominate X-inefficiencies. These are important findings because they contrast with the results of previous studies on Japanese banking. In particular, the results indicate an alternative policy prescription, namely, that the largest banks should shrink to benefit from scale advantages. It also seems that financial capital has the largest influence on optimal bank size.

Dynamic fuzzy neural networks-a novel approach to function approximation

Abstract: In this paper, an architecture of dynamic fuzzy neural networks (D-FNN) implementing Takagi-Sugeno-Kang (TSK) fuzzy systems based on extended radial basis function (RBF) neural networks is proposed. A novel learning algorithm based on D-FNN is also presented. The salient characteristics of the algorithm are: 1) hierarchical on-line self-organizing learning is used; 2) neurons can be recruited or deleted dynamically according to their significance to the system's performance; and 3) fast learning speed can be achieved. Simulation studies and comprehensive comparisons with some other learning algorithms demonstrate that a more compact structure with higher performance can be achieved by the proposed approach.

Performance of smart piezoceramic patches in health monitoring of a RC bridge

Abstract: This paper presents the results of a health monitoring study, carried out during the destructive load testing of a prototype reinforced concrete (RC) bridge. The bridge was made up of cement-concrete reinforced with steel rods, and represented a popular class of road bridges in which regular health monitoring is a very important issue during the service life. The bridge was instrumented with piezoceramic transducer (PZT) patches, which were electrically excited at high frequencies, of the order of kHz, and the real part of admittance (conductance) was extracted as a function of the exciting frequency. The patches were scanned for the acquisition of this signature at various stages during the loading process. The signatures of the patches located in the vicinity of the damage were found to have undergone drastic changes, while those farther away were less affected. Damage was quantified in non-parametric terms using the root mean square of the deviation in signatures with respect to the baseline signature of the healthy state. This non-parametric index was found to correlate well with the damage progression in the structure.

3D human face recognition using point signature

Abstract: We present a novel face recognition algorithm based on the point signature-a representation for free-form surfaces. We treat the face recognition problem as a non-rigid object recognition problem. The rigid parts of the face of one person are extracted after registering the range data sets of faces having different facial expressions. These rigid parts are used to create a model library for efficient indexing. For a test face, models are indexed from the library and the most appropriate models are ranked according to their similarity with the test face. Verification of each model face can be quickly and efficiently identified. Experimental results with range data involving six human subjects, each with four different facial expressions, have demonstrated the validity and effectiveness of our algorithm.

Consumers’ perceptions of the country‐of‐origin effect on purchasing intentions of (in)conspicuous products

Abstract: The country‐of‐origin effect and product consumption conspicuousness are examined. This study strengthens our understanding of the importance of the COO effect as it is investigated with respect to consumers’ purchasing intentions of public vs. private and luxury vs. necessity products. For instance, does the COO effect differ in its importance in the purchasing decision of conspicuous vs. inconspicuous products? A product’s country of origin has a stronger effect when considering luxury products. The conspicuous aspect of the consumption comes second.

Strain rate sensitivity of a closed-cell aluminum foam

Abstract: An experimental investigation into the strain rate sensitivity of a closed-cell aluminum foam at room temperature and under compression loading is conducted. The nominal strain rates are varied by four orders of magnitude, from 3.33×10−5 to 1.6×10−1 s−1. Within this range, experimental results show that the plastic strength and the energy absorbed increase (by 31 and 52.5%, respectively) with increasing strain rate. However, the plastic strength was found to increase bilinearly with the logarithm of strain rate, whereas dense metals tend to show only a linear response. As is the case with dense metals, the strain rate sensitivity of the foam was not a constant value, but found to be dependent on the strain and incremental change in strain rate. These results are explained with the aid of suitable micromechanical models such as microinertial effects against the bucking of cell walls at high strain rates that are unique to foams.

Nonlinear control of interior permanent-magnet synchronous motor

Abstract: This paper presents a novel speed control technique for an interior permanent-magnet synchronous motor (IPMSM) drive based on newly developed adaptive backstepping technique. The proposed stabilizing feedback law for the IPMSM drive is shown to be globally asymptotically stable in the context of Lyapunov theory. The adaptive backstepping technique takes system nonlinearities into account in the control system design stage. The detailed derivations of the control laws have been given for controller design. The complete IPMSM drive incorporating the proposed backstepping control technique has been successfully implemented in real-time using digital signal processor board DS1102 for a laboratory 1-hp motor. The performance of the proposed drive is investigated both in experiment and simulation at different operating conditions. It is found that the proposed control technique provides a good speed tracking performance for the IPMSM drive ensuring the global stability.

Probabilistic neural-network structure determination for pattern classification

Abstract: Network structure determination is an important issue in pattern classification based on a probabilistic neural network. In this study, a supervised network structure determination algorithm is proposed. The proposed algorithm consists of two parts and runs in an iterative way. The first part identifies an appropriate smoothing parameter using a genetic algorithm, while the second part determines suitable pattern layer neurons using a forward regression orthogonal algorithm. The proposed algorithm is capable of offering a fairly small network structure with satisfactory classification accuracy.

Determination of nonlinear absorption and refraction by single Z-scan method

Abstract: We report a simplified Z-scan technique based on a study on the symmetric features of a typical Z-scan curve. The contributions from the two-photon absorption (TPA) and the nonlinear refraction (NLR) are easily separated from a closed-aperture Z-scan curve using this method. And the determination of the two nonlinearities is simplified and unambiguous. We demonstrate this method on ZnSe, CdS, and ZnTe semiconductors with 120-fs laser pulses. And the influence from the uncertainty of the focal plane (Z=0) position is discussed. It is also found that the TPA coefficient can be obtained independently without knowing the exact location of the focal point.

Transaction Cost and Resource-Based Explanations of Joint Ventures: A Comparison and Synthesis

Abstract: Transaction cost theory has been the dominant theoretical lens used in the study of joint ventures. The purpose of this paper is to explain the formation of joint ventures from the resource-based perspective and to compare this perspective with transaction cost theory. By focusing on the cost aspect of a transaction, the transaction cost logic explains joint ventures in terms of market failure for intermediate inputs, asset specificity, and high uncertainty over specifying and monitoring performance. Putting more emphasis on the benefit side of a transaction, resource-based theory regards joint ventures as a means of exploiting and developing a firm's resources. The transaction cost and resource-based explanations are, to a certain extent, complementary. Taking the stance of theoretical pluralism, an attempt is made to synthesize the two theories into a more comprehensive perspective which takes both costs and benefits into account.

Dynamic Assessment of Curved Cable-Stayed Bridge by Model Updating

Abstract: Bridges are indispensable components of the infrastructure of modern society, and their assessment via techniques of structural dynamics is assuming greater importance. This assessment concerns performance of the as-built structure compared to the design and can also extend to the assessment of structural deterioration or damage. Simple validation of numerical results by dynamic testing has met some success; however, feedback from testing into analysis is usually crude, and only recently have systematic techniques been developed that can be supplied to such structures. This paper investigates the application of sensitivity-based model updating technology to the dynamic assessment of the Safti Link Bridge, a curved cable-stayed bridge in Singapore. Based on the measured modal data from prototype testing, the simulated dynamic properties obtained via finite- element analysis have been significantly improved by modification of uncertain structural parameters such as Young's modulus of concrete and structural geometry. Cable-stayed bridges with modern distinctive styles are in- creasing in number worldwide. These bridges are now built in more unusual styles for structural and aesthetic reasons (Menn 1996; Rito 1996). Examples include the Lerez Bridge (Troy- ano et al. 1998), a single inclined tower bridge; the Katsushika Harp Bridge (Takenouchi 1998), with a single pylon and S- shaped deck; the Marian Bridge (Kominek 1998), with a single L-shaped pylon; the Alamillo Bridge (Casa 1995), with a sin- gle inclined pylon; and the Safti Link Bridge (Tan 1996), which has a curved deck and single offset pylon. The unique structural styles of these bridges beautify the environment but also add to the difficulties in accurate structural analysis. The accurate assessment of these and other types of bridges using dynamics-based methods has become of increasing concern due to their infrastructural role. Dynamics-based assessment (Severn et al. 1989; Felber 1995; Law and Ko 1995; Felber and Cantieni 1996) of these unusual bridges is based on a comparison of the experimental modal analysis (EMA) data obtained during full-scale tests with the finite-element analysis (FEA) predictions. One purpose of the comparison is so that the finite-element (FE) models can be used to predict performance during unusual loads such as earth- quakes (Dumanoglu et al. 1991; Brownjohn et al. 1992). Even if the resulting response is large enough that material and ge- ometric nonlinearities become significant, the starting point for nonlinear analysis would be a realistic linear model. For ex- ample, in the case of a suspension bridge, the large cable os- cillations will vary the geometric stiffness, which can be accom- modated in nonlinear analyses if the operating tension is known. Material nonlinearities can also be incorporated based on the low level characteristics. Other motivations for dynamics-based assessment include the validation of design assumptions em- bodied in the FE model and health assessment (i.e., the iden- tification of structural deterioration or damage). Confidence in using FE models for performance predictions may be lacking due to relatively large differences between experimental and analytical modes. The differences come not 1

Dynamic voltage restoration with minimum energy injection

Abstract: Summary form only given, as follows. Voltage sags are one of the most important power quality problems challenging the utility industry. Voltage sags can be compensated for by voltage and power injection into the distribution system. By injecting voltage with a phase advance with respect to the sustained source-side voltage, reactive power can be utilized to help voltage restoration. Hence, the consumption of real power, from the perspective of the energy supply device, can be reduced. This energy-saving voltage injection comes at the expense of an increased voltage injection magnitude, load power swing phase shift and discontinuity of voltage wave-shape. For this reason, several proposed compensation strategies are examined, in term of satisfying custom power while taking into consideration the capacity of the energy-storage device and the voltage injection constraint of the dynamic voltage restorer. Numerical examples are included to illustrate the efficacy of the proposed control strategies.

An Implementation of Active Learning and its Effect on the Quality of Student Learning

Abstract: This paper examines the effectiveness of active learning implemented in two undergraduate programmes at the Hong Kong Polytechnic University. Several learning activities were implemented during student seminar sessions. The effectiveness of these activities was investigated using questionnaires and interviews to explore student attitudes as well as the Study Process Questionnaire to measure student approaches to learning. Results showed that active learning made a valuable contribution to the development of independent learning skills and the ability to apply knowledge. It also helped to create interest in the curriculum and to prepare students for their future careers. The activities used affected the quality of student learning by shaping the way that students studied and meeting desired learning outcomes. The results are discussed in the context of student approaches to learning and in relation to the programmes' educational objectives.

Classification ability of single hidden layer feedforward neural networks

Abstract: Multilayer perceptrons with hard-limiting (signum) activation functions can form complex decision regions. It is well known that a three-layer perceptron (two hidden layers) can form arbitrary disjoint decision regions and a two-layer perceptron (one hidden layer) can form single convex decision regions. This paper further proves that single hidden layer feedforward neural networks (SLFN) with any continuous bounded nonconstant activation function or any arbitrary bounded (continuous or not continuous) activation function which has unequal limits at infinities (not just perceptrons) can form disjoint decision regions with arbitrary shapes in multidimensional cases, SLFN with some unbounded activation function can also form disjoint decision regions with arbitrary shapes.

Avoiding Competence Substitution Through Knowledge Sharing

Abstract: Causal ambiguity protects distinctive competencies from imitation but might increase a firm's vulnerability to substitution. The authors suggest that firms can manage this tension by identifying the causes of superior performance and using this knowledge to make their commitments to key stakeholders more credible. Credible commitment allows a firm to influence its stakeholders and thereby simultaneously delay substitution and control the threat of imitation.

A Synthetic Control Chart for Detecting Small Shifts in the Process Mean

Abstract: This paper presents a synthetic control chart that is an integration of the Shewhart X chart and the conforming run length chart. Like the Shewhart X chart, the synthetic chart is used to detect ...