Showing papers by "City University of Hong Kong published in 2005"

Behavioral intention formation in knowledge sharing: examining the roles of extrinsic motivators, social-psychological factors, and organizational climate

Abstract: Individuals' knowledge does not transform easily into organizational knowledge even with the implementation of knowledge repositories. Rather, individuals tend to hoard knowledge for various reasons. The aim of this study is to develop an integrative understanding of the factors supporting or inhibiting individuals' knowledge-sharing intentions. We employ as our theoretical framework the theory of reasoned action (TRA), and augment it with extrinsic motivators, social-psychological forces and organizational climate factors that are believed to influence individuals' knowledge- sharing intentions. Through a field survey of 154 managers from 27 Korean organizations, we confirm our hypothesis that attitudes toward and subjective norms with regard to knowledge sharing as well as organizational climate affect individuals' intentions to share knowledge. Additionally, we find that anticipated reciprocal relationships affect individuals' attitudes toward knowledge sharing while both sense of self-worth and organizational climate affect subjective norms. Contrary to common belief, we find anticipated extrinsic rewards exert a negative effect on individuals' knowledge-sharing attitudes.

Contributing knowledge to electronic knowledge repositories: an empirical investigation

Abstract: Organizations are attempting to leverage their knowledge resources by employing knowledge management (KM) systems, a key form of which are electronic knowledge repositories (EKRs). A large number of KM initiatives fail due to the reluctance of employees to share knowledge through these systems. Motivated by such concerns, this study formulates and tests a theoretical model to explain EKR usage by knowledge contributors. The model employs social exchange theory to identify cost and benefit factors affecting EKR usage, and social capital theory to account for the moderating influence of contextual factors. The model is validated through a large-scale survey of public sector organizations. The results reveal that knowledge self-efficacy and enjoyment in helping others significantly impact EKR usage by knowledge contributors. Contextual factors (generalized trust, pro-sharing norms, and identification) moderate the impact of codification effort, reciprocity, and organizational reward on EKR usage, respectively. It can be seen that extrinsic benefits (reciprocity and organizational reward) impact EKR usage contingent on particular contextual factors whereas the effects of intrinsic benefits (knowledge self-efficacy and enjoyment in helping others) on EKR usage are not moderated by contextual factors. The loss of knowledge power and image do not appear to impact EKR usage by knowledge contributors. Besides contributing to theory building in KM, the results of this study inform KM practice.

The East Asian summer monsoon: an overview

Abstract: The present paper provides an overview of major problems of the East Asian summer monsoon. The summer monsoon system over East Asia (including the South China Sea (SCS)) cannot be just thought of as the eastward and northward extension of the Indian monsoon. Numerous studies have well documented that the huge Asian summer monsoon system can be divided into two subsystems: the Indian and the East Asian monsoon system which are to a greater extent independent of each other and, at the same time, interact with each other. In this context, the major findings made in recent two decades are summarized below: (1) The earliest onset of the Asian summer monsoon occurs in most of cases in the central and southern Indochina Peninsula. The onset is preceded by development of a BOB (Bay of Bengal) cyclone, the rapid acceleration of low-level westerlies and significant increase of convective activity in both areal extent and intensity in the tropical East Indian Ocean and the Bay of Bengal. (2) The seasonal march of the East Asian summer monsoon displays a distinct stepwise northward and northeastward advance, with two abrupt northward jumps and three stationary periods. The monsoon rain commences over the region from the Indochina Peninsula-the SCS-Philippines during the period from early May to mid-May, then it extends abruptly to the Yangtze River Basin, and western and southern Japan, and the southwestern Philippine Sea in early to mid-June and finally penetrates to North China, Korea and part of Japan, and the topical western West Pacific. (3) After the onset of the Asian summer monsoon, the moisture transport coming from Indochina Peninsula and the South China Sea plays a crucial “switch” role in moisture supply for precipitation in East Asia, thus leading to a dramatic change in climate regime in East Asia and even more remote areas through teleconnection. (4) The East Asian summer monsoon and related seasonal rain belts assumes significant variability at intraseasonal, interannual and interdecadal time scales. Their interaction, i.e., phase locking and in-phase or out-phase superimposing, can to a greater extent control the behaviors of the East Asian summer monsoon and produce unique rythem and singularities. (5) Two external forcing i.e., Pacific and Indian Ocean SSTs and the snow cover in the Eurasia and the Tibetan Plateau, are believed to be primary contributing factors to the activity of the East Asian summer monsoon. However, the internal variability of the atmospheric circulation is also very important. In particular, the blocking highs in mid-and high latitudes of Eurasian continents and the subtropical high over the western North Pacific play a more important role which is quite different from the condition for the South Asian monsoon. The later is of tropical monsoon nature while the former is of hybrid nature of tropical and subtropical monsoon with intense impact from mid-and high latitudes.

Culture and international business: recent advances and their implications for future research

Abstract: The paper provides a state-of-the-art review of several innovative advances in culture and international business (IB) to stimulate new avenues for future research. We first review the issues surrounding cultural convergence and divergence, and the processes underlying cultural changes. We then examine novel constructs for characterizing cultures, and how to enhance the precision of cultural models by pinpointing when cultural effects are important. Finally, we examine the usefulness of experimental methods, which are rarely used by IB researchers. Implications of these path-breaking approaches for future research on culture and IB are discussed.

Input-based and time-based models of international adjustment: Meta-analytic evidence and theoretical extensions

Abstract: Integrating work on international assignments and domestic stress, we conducted meta-analyses of over 50 determinants and consequences of expatriate adjustment using data from 8,474 expatriates in ...

A time-varying complex dynamical network model and its controlled synchronization criteria

Abstract: Today, complex networks have attracted increasing attention from various fields of science and engineering. It has been demonstrated that many complex networks display various synchronization phenomena. In this note, we introduce a time-varying complex dynamical network model. We then further investigate its synchronization phenomenon and prove several network synchronization theorems. Especially, we show that synchronization of such a time-varying dynamical network is completely determined by the inner-coupling matrix, and by the eigenvalues and the corresponding eigenvectors of the coupling configuration matrix of the network.

Progressive skyline computation in database systems

Abstract: The skyline of a d-dimensional dataset contains the points that are not dominated by any other point on all dimensions. Skyline computation has recently received considerable attention in the database community, especially for progressive methods that can quickly return the initial results without reading the entire database. All the existing algorithms, however, have some serious shortcomings which limit their applicability in practice. In this article we develop branch-and-bound skyline (BBS), an algorithm based on nearest-neighbor search, which is I/O optimal, that is, it performs a single access only to those nodes that may contain skyline points. BBS is simple to implement and supports all types of progressive processing (e.g., user preferences, arbitrary dimensionality, etc). Furthermore, we propose several interesting variations of skyline computation, and show how BBS can be applied for their efficient processing.

Dielectric Resonator Antennas

Abstract: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article. In the latter case, a parasitic patch is used to excite a nearly degenerate mode. The hemispherical DRA, excited in its fundamental broadside TE111 mode, is used for the demonstration. In the analysis, the mode-matching method is used to obtain the Green's functions, whereas the method of moments is used to solve for the unknown strip currents. In order to solve the singularity problem of the Green's functions, a recurrence technique is used to evaluate the impedance integrals. This greatly increases the numerical efficiency. Measurements were carried out to verify the calculations, with good results. Keywords: circularly polarized antenna; dielectric antennas; mode-matching methods; moment methods; parasitic antennas; resonance

Empirical Exchange Rate Models of the Nineties: Are Any Fit to Survive?

Abstract: Previous assessments of nominal exchange rate determination have focused upon a narrow set of models typically of the 1970's vintage. The canonical papers in this literature are by Meese and Rogoff (1983, 1988), who examined monetary and portfolio balance models. Succeeding works by Mark (1995) and Chinn and Meese (1995) focused on similar models. In this paper we re-assess exchange rate prediction using a wider set of models that have been proposed in the last decade: interest rate parity, productivity based models, and behavioral equilibrium exchange rate' models. The performance of these models is compared against a benchmark model the Dornbusch-Frankel sticky price monetary model. The models are estimated in error correction and first-difference specifications. Rather than estimating the cointegrating vector over the entire sample and treating it as part of the ex ante information set as is commonly done in the literature, we recursively update the cointegrating vector, thereby generating true ex ante forecasts. We examine model performance at various forecast horizons (1 quarter, 4 quarters, 20 quarters) using differing metrics (mean squared error, direction of change), as well as the consistency' test of Cheung and Chinn (1998). No model consistently outperforms a random walk, by a mean squared error measure; however, along a direction-of-change dimension, certain structural models do outperform a random walk with statistical significance. Moreover, one finds that these forecasts are cointegrated with the actual values of exchange rates, although in a large number of cases, the elasticity of the forecasts with respect to the actual values is different from unity. Overall, model/specification/currency combinations that work well in one period will not necessarily work well in another period.

Perfluorinated Compounds in Aquatic Organisms at Various Trophic Levels in a Great Lakes Food Chain

Abstract: Trophic transfer of perfluorooctanesulfonate (PFOS) and other related perfluorinated compounds was examined in a Great Lakes benthic foodweb including water–algae–zebra mussel–round goby–smallmouth bass. In addition, perfluorinated compounds were measured in livers and eggs of Chinook salmon and lake whitefish, in muscle tissue of carp, and in eggs of brown trout collected from Michigan. Similarly, green frog livers, snapping turtle plasma, mink livers, and bald eagle tissues were analyzed to determine concentrations in higher trophic-level organisms in the food chain. PFOS was the most widely detected compound in benthic organisms at various trophic levels. Concentrations of PFOS in benthic invertebrates such as amphipods and zebra mussels were approximately 1000-fold greater than those in surrounding water, which suggested a bioconcentration factor (BCF; concentration in biota/concentration in water) of 1000 in benthic invertebrates. Concentrations of PFOS in round gobies were two- to fourfold greater than those in their prey organisms such as zebra mussels and amphipods. Concentrations of PFOS in predatory fishes (Chinook salmon and lake whitefish) were 10 to 20-fold greater than those in their prey species. Concentrations of PFOS in mink and bald eagles were, on average, 5- to 10-fold greater than those in Chinook salmon, carp, or snapping turtles. Because of the accumulation of PFOS in liver and blood, the biomagnification factor (BMF) of perfluorinated compounds in higher trophic-level organisms such as salmonid fishes, mink, and eagles were based on the concentrations in livers or plasma. Overall, these results suggest a BCF of PFOS of approximately 1000 (whole-body based) in benthic invertebrates, and a BMF of 10 to 20 in mink or bald eagles, relative to their prey items. Eggs of fish contained notable concentrations of PFOS, suggesting oviparous transfer of this compound. PFOA was found in water, but its biomagnification potential was lower than that of PFOS.

Generating hyperchaos via state feedback control

Abstract: In this letter, a simple nonlinear state feedback controller is designed for generating hyperchaos from a three-dimensional autonomous chaotic system. The hyperchaotic system is not only demonstrated by computer simulations but also verified with bifurcation analysis, and is implemented experimentally via an electronic circuit.

Ownership concentration, firm performance, and dividend policy in Hong Kong

Abstract: We analyze a sample of 412 publicly listed Hong Kong firms during 1995–1998 in order to answer three questions. Does concentrated family ownership affect firm operating performance and value? Does it affect dividend policy? What is the impact of corporate governance on performance, value, and dividend payouts? Our results do not show a positive relationship between family ownership and return on assets, return on equity or the market-to-book ratio. In addition, we find a negative relationship between CEO duality and performance (where CEO duality is much more likely in family-controlled firms). We also find little relationship between family ownership and dividend policy. Only for small firms there is a significant negative relationship between dividend payouts and family ownership up to 10% of the company's stock and a positive relationship for family ownership between 10 and 35%. Dividend payouts in small firms also show little sensitivity to performance. Finally, the composition of the board of directors (proportion of independent non-executive directors, outsider-dominated board, presence of audit committees) has little impact on firm performance and dividend policy, particularly for small market capitalization firms. Our results for Hong Kong are in line with both Demsetz and Lehn (1985) [Demsetz, H., Lehn, K., 1985. The structure of corporate ownership: causes and consequences. Journal of Political Economy 93, 1155–1177] and Himmelberg et al. (1999) [Himmelberg, C.P., Hubbard, R.G., Palia, D., 1999. Understanding the determinants of managerial ownership and the link between ownership and performance. Journal of Financial Economics 53. 353–384], who show that concentrated ownership is not associated with better operating performance or higher firm valuation.

State estimation for delayed neural networks

Abstract: In this letter, the state estimation problem is studied for neural networks with time-varying delays. The interconnection matrix and the activation functions are assumed to be norm-bounded. The problem addressed is to estimate the neuron states, through available output measurements, such that for all admissible time-delays, the dynamics of the estimation error is globally exponentially stable. An effective linear matrix inequality approach is developed to solve the neuron state estimation problem. In particular, we derive the conditions for the existence of the desired estimators for the delayed neural networks. We also parameterize the explicit expression of the set of desired estimators in terms of linear matrix inequalities (LMIs). Finally, it is shown that the main results can be easily extended to cope with the traditional stability analysis problem for delayed neural networks. Numerical examples are included to illustrate the applicability of the proposed design method.

The Center for Epidemiologic Studies Depression Scale in older Chinese: thresholds for long and short forms.

Abstract: Objective No study has examined the diagnostic validity of the Center for Epidemiologic Studies Depression Scale (CES-D) in the Chinese elderly. This study aims to determine appropriate cutoffs for the 20- (CESD-20) as well as a ten-item (CESD-10) version of the instrument. Data were also provided, based on simulated scoring, for the diagnostic performance of the scales when using dichotomous instead of 4-point rating scales. Methods Three hundred and ninety eight persons aged 60 +referred for psychiatric asssessment by a physician were administered the CES-D as well as given an independent psychiatric assessment. A spectrum of depression diagnosis as the criterion was used to assess the diagnostic validity of the CES-D. Results The ten and the 20-item version of the CES-D, regardless of scoring method, produced essentially identical performance indices. The optimal thresholds were 12 and 22 for CESD-10 and CESD-20 respectively, and based on these thresholds, sensitivity, specificity, positive predictive value and negative predictive value were 0.76, 0.55, 0.57 and 0.74 for CESD-10, and 0.75, 0.51, 0.55 and 0.72 for CESD-20. With both ends of the rating scale collapsed to create dichotomous items, the optimal thresholds became 4 for CESD-10 and 7 for CESD-20, and the correponding performance indices were 0.67, 0.58, 0.56 and 0.69 for CESD-10, and 0.70, 0.58, 0.57 and 0.70 for CESD-20. Conclusions The ten-item version can be used in lieu of the 20-item version, and a dichotomous response format would probably work as well as the original four-point format, in order to simplify administration for elderly persons. Copyright © 2005 John Wiley & Sons, Ltd.

A systematic approach to quality function deployment with a full illustrative example

Abstract: This paper presents a systematic and operational approach to quality function deployment (QFD), a customer-driven quality management system for product development. After a comprehensive description of the relevant elements in house of quality (HOQ), the first and most influential phase of the QFD system, a 9-step model is proposed to help build such an HOQ. A number of 9-point scales are developed whose uses could help unify the various measurements in HOQ to avoid arbitrariness. Special attention is paid to the various subjective assessments in the HOQ process, and symmetrical triangular fuzzy numbers (STFNs) are suggested for use to capture the vagueness in people's linguistic assessments. Instead of using the quite subjective sales-point concept, entropy method is introduced to conduct competitive analysis and derive competitive priority ratings. A thorough explanation is given to address the concepts, computations and implementations in the proposed HOQ model, followed by a full example for a fried Chinese vegetable to illustrate step by step all the relevant details with the purpose of facilitating the understanding and application of the QFD process. Two difficult parts omitted from our model, especially the correlation matrices, are discussed in some detail finally, and possible approaches are also suggested to deal with them in a potentially more complete HOQ model.

Buckling analysis of multi-walled carbon nanotubes: a continuum model accounting for van der Waals interaction

Abstract: Explicit formulas are derived for the van der Waals (vdW) interaction between any two layers of a multi-walled carbon nanotube (CNT). Based on the derived formulas, an efficient algorithm is established for the buckling analysis of multi-walled CNTs, in which individual tubes are modeled as a continuum cylindrical shell. The explicit expressions are also derived for the buckling of double-walled CNTs. In previous studies by Ru (J. Appl. Phys. 87 (2000b) 7227) and Wang et al. (Int. J. Solids Struct. 40 (2003) 3893), only the vdW interaction between adjacent two layers was considered and the vdW interaction between the other two layers was neglected. The vdW interaction coefficient was treated as a constant that was not dependent on the radii of the tubes. However, the formulas derived herein reveal that the vdW interaction coefficients are dependent on the change of interlayer spacing and the radii of the tubes. With the increase of radii, the coefficients approach constants, and the constants between two adjacent layers are about 10% higher than those reported by Wang et al. (Int. J. Solids. Struct. 40 (2003) 3893). In addition, the numerical results show that the vdW interaction will lead to a higher critical buckling load in multi-walled CNTs. The effect of the tube radius on the critical buckling load of a multi-walled CNT is also examined.

Video summarization and scene detection by graph modeling

Abstract: We propose a unified approach for video summarization based on the analysis of video structures and video highlights. Two major components in our approach are scene modeling and highlight detection. Scene modeling is achieved by normalized cut algorithm and temporal graph analysis, while highlight detection is accomplished by motion attention modeling. In our proposed approach, a video is represented as a complete undirected graph and the normalized cut algorithm is carried out to globally and optimally partition the graph into video clusters. The resulting clusters form a directed temporal graph and a shortest path algorithm is proposed to efficiently detect video scenes. The attention values are then computed and attached to the scenes, clusters, shots, and subshots in a temporal graph. As a result, the temporal graph can inherently describe the evolution and perceptual importance of a video. In our application, video summaries that emphasize both content balance and perceptual quality can be generated directly from a temporal graph that embeds both the structure and attention information.

On the dynamical degradation of digital piecewise linear chaotic maps

Abstract: When chaotic systems are realized with finite precisions in digital computers, their dynamical properties are often found to be entirely different from the original versions in the continuous setting. In the literature, there does not seem to be much work on quantitative analysis of such degradation of digitized chaos and how to reduce its negative influence on chaos-based digital systems. Focusing on 1D piecewise linear chaotic maps (PWLCM), this paper reports some findings on a new series of dynamical indicators, which can quantitatively reflect the degradation effects on a digital PWLCM realized with a fixed-point finite precision. On top of that, the paper introduces a new method for studying digital chaos from an algorithmic point of view. In addition, the theoretical results obtained in this paper should be very helpful for the consideration of reducing negative influence of dynamical degradation in real design of various digital chaotic systems. As typical examples, the proposed dynamical indicators are applied to the performance comparison of different remedies for improving dynamical degradation, cryptanalysis of digital chaotic ciphers based on 1D PWLCM, and design of chaotic pseudo-random number generators with desired characteristics.

Resonant Raman scattering in cubic and hexagonal boron nitride

Abstract: We measured first- and second-order Raman scattering in cubic and hexagonal boron nitride using excitation energies in the visible and in the UV. The nonresonant first-order Raman susceptibilities for cubic and hexagonal BN are 1 and $10\phantom{\rule{0.3em}{0ex}}{\mathrm{\AA{}}}^{2}$, respectively. Raman scattering is thus very powerful in detecting the hexagonal phase in mixed thin boron nitride films. In cubic BN the constant Raman sucseptibility in the visible and the UV is due to its indirect band gap. For hexagonal BN a Raman enhancement is found at $5.4\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. It is well explained by the energy dependence of the dielectric function of hexagonal BN. The second-order spectrum of cubic boron nitride is in excellent agreement with first-principles calculations of the phonon density of states. In hexagonal BN the overbending of the LO phonon is $\ensuremath{\approx}100\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, five times larger than in graphite.