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Showing papers by "Hong Kong University of Science and Technology published in 2006"


01 Jan 2006
TL;DR: In this article, the authors examine how cultural differences influence the returns of momentum strategies and find that individualism is positively associated with trading volume and volatility, as well as with the magnitude of momentum profits, and that momentum profits are also positively related to analyst forecast dispersion, transaction costs, and the familiarity of the market to foreigners.
Abstract: This paper examines how cultural differences influence the returns of momentum strategies. Cross-country cultural differences are measured with an individualism index developed by Hofstede (2001), which is related to overconfidence and self-attribution bias. We find that individualism is positively associated with trading volume and volatility, as well as to the magnitude of momentum profits. Momentum profits are also positively related to analyst forecast dispersion, transaction costs, and the familiarity of the market to foreigners, and negatively related to firm size and volatility. However, the addition of these and other variables does not dampen the relation between individualism and momentum profits.

951 citations


Journal ArticleDOI
TL;DR: In this article, the authors report on a study that attempts to expand the set of post-adoption beliefs in the expectation-confirmation model (ECM) in order to extend the application of the ECM beyond an instrumental focus.
Abstract: The expectation-confirmation model (ECM) of IT continuance is a model for investigating continued information technology (IT) usage behavior. This paper reports on a study that attempts to expand the set of post-adoption beliefs in the ECM, in order to extend the application of the ECM beyond an instrumental focus. The expanded ECM, incorporating the post-adoption beliefs of perceived usefulness, perceived enjoyment and perceived ease of use, was empirically validated with data collected from an on-line survey of 811 existing users of mobile Internet services. The data analysis showed that the expanded ECM has good explanatory power (R^2=57.6% of continued IT usage intention and R^2=67.8% of satisfaction), with all paths supported. Hence, the expanded ECM can provide supplementary information that is relevant for understanding continued IT usage. The significant effects of post-adoption perceived ease of use and perceived enjoyment signify that the nature of the IT can be an important boundary condition in understanding the continued IT usage behavior. At a practical level, the expanded ECM presents IT product/service providers with deeper insights into how to address IT users' satisfaction and continued patronage.

931 citations


Journal ArticleDOI
TL;DR: This short article serves to summarize the 10 most challenging problems of the 14 responses the authors have received from this survey, by consulting some of the most active researchers in data mining and machine learning.
Abstract: In October 2005, we took an initiative to identify 10 challenging problems in data mining research, by consulting some of the most active researchers in data mining and machine learning for their opinions on what are considered important and worthy topics for future research in data mining. We hope their insights will inspire new research efforts, and give young researchers (including PhD students) a high-level guideline as to where the hot problems are located in data mining. Due to the limited amount of time, we were only able to send out our survey requests to the organizers of the IEEE ICDM and ACM KDD conferences, and we received an overwhelming response. We are very grateful for the contributions provided by these researchers despite their busy schedules. This short article serves to summarize the 10 most challenging problems of the 14 responses we have received from this survey. The order of the listing does not reflect their level of importance.

884 citations


PatentDOI
TL;DR: In this article, a convenient process for the regioselective synthesis of 1,5-disubstituted 1,2,3-triazoles and 1,4,5-trisubstitized 1, 2,3, 4,5, 5 triazoles from organic azides and alkynes employs catalytic ruthenium.
Abstract: A convenient process for the regioselective synthesis of 1 ,5-disubstituted 1 ,2,3-triazoles and 1 ,4,5-trisubstituted 1 ,2,3-triazoles from organic azides and alkynes employs catalytic ruthenium.

876 citations


Posted Content
TL;DR: The authors argue that high-performance work systems generate a high level of collective human capital and encourage a high degree of social exchange within an organization, and that these are positively related to the organization's overall performance.
Abstract: The resource-based view of the firm and social exchange perspectives are invoked to hypothesize linkages among high-performance work systems, collective human capital, the degree of social exchange in an establishment, and establishment performance. The authors argue that high-performance work systems generate a high level of collective human capital and encourage a high degree of social exchange within an organization, and that these are positively related to the organization's overall performance. On the basis of a sample of Japanese establishments, the results provide support for the existence of these mediating mechanisms through which high-performance work systems affect overall establishment performance.

753 citations


Journal ArticleDOI
TL;DR: ZnO nanorod arrays were fabricated using a hydrothermal method and found that, while the defect emission can be significantly reduced by annealing at 200 degrees C, the rods still have large defect concentrations as confirmed by their low positron diffusion length and short PL decay time constants.
Abstract: ZnO nanorod arrays were fabricated using a hydrothermal method. The nanorods were studied by scanning electron microscopy, photoluminescence (PL), time-resolved PL, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy before and after annealing in different environments and at different temperatures. Annealing atmosphere and temperature had significant effects on the PL spectrum, while in all cases the positron diffusion length and PL decay times were increased. We found that, while the defect emission can be significantly reduced by annealing at 200 °C, the rods still have large defect concentrations as confirmed by their low positron diffusion length and short PL decay time constants.

722 citations


Journal ArticleDOI
01 Dec 2006
Abstract: This study examines the utility of three prospective models for understanding the continued IT usage behavior. The three models include: Expectation-Confirmation Model in IT Domain (ECM-IT), Technology Acceptance Model (TAM), and a hybrid model integrating TAM and ECM-IT (extended ECM-IT). Based on a survey of 1826 mobile Internet users, the LISREL analysis shows that all three models meet the various goodness-of-fit criteria. When compared using special indices for differentiating among alternative good models, TAM has the best fit to the data followed by ECM-IT, and the extended ECM-IT. In terms of variance explained for intention to continue IT usage, the extended ECM-IT has the highest R2 (67%) followed by TAM (63%), and ECM-IT (50%). We conclude that TAM is the most parsimonious and generic model that can be used to study both initial and continued IT adoption; the extended ECM-IT explains continued IT usage behavior as well as TAM; and both the ECM-IT and extended ECM-IT models provide additional information to increase our understanding of continued IT usage.

717 citations


Journal ArticleDOI
TL;DR: A general strategy to generate biofunctional magnetic nanoparticles is highlighted, applications for these nanoparticles in protein separation and pathogen detection are illustrated, and the high sensitivity and high selectivity achieved by this system are analyzed.

671 citations


Journal ArticleDOI
TL;DR: The findings show that the determinants of multipurpose information appliance adoption decisions are not only different from those in the workplace, but are also dependent on the nature of the target technology and its usage context.
Abstract: We have come to a stage when information technology (IT) innovations have permeated every walk of life. Many new technologies can be used for many different purposes and in different contexts other than the workplace. The current study attempts to understand individual adoption of IT innovations that are used beyond work settings. We define a new class of IT innovations called multipurpose information appliances, which are personal, universally accessible, and multipurpose. The ubiquitous nature of these appliances has led to a constant permeability between the separate contexts of social life. An adoption model that reflects the unique characteristics and usage contexts of multipurpose information appliances was developed. The model consists of five sets of adoption factors and was tested using data collected on mobile data services adoption. Our findings show that the determinants of multipurpose information appliance adoption decisions are not only different from those in the workplace, but are also dependent on the nature of the target technology and its usage context. Theoretical and practical implications of the findings are discussed.

657 citations


Posted Content
TL;DR: The authors examined how accounting quality relates to firm-level capital investment efficiency and found that higher quality accounting enhances investment efficiency by reducing information asymmetry between managers and outside suppliers of capital, and that this effect should be stronger in economies where financing is largely provided through arm's-length transactions compared with countries where creditors supply more capital.
Abstract: This study examines how accounting quality relates to firm-level capital investment efficiency. Our first hypothesis is that higher quality accounting enhances investment efficiency by reducing information asymmetry between managers and outside suppliers of capital. Our second hypothesis is that this effect should be stronger in economies where financing is largely provided through arm's-length transactions compared with countries where creditors supply more capital. Our results are consistent with these hypotheses both across and within countries. They are robust to alternative econometric specifications, different measures of accounting quality and investment-cash flow sensitivity, and numerous control variables.

626 citations


Journal ArticleDOI
TL;DR: An integrative model to study the determinants of post-adoption stages of innovation diffusion using enterprise digital transformation as an example of technology-enabled innovations indicates that innovation diffusion can be better understood by including both innovation characteristics and contextual factors, whereas earlier literature has traditionally treated the two separately.
Abstract: Grounded in the diffusion of innovation theory and the technology–organization–environment framework, we develop an integrative model to study the determinants of post-adoption stages of innovation diffusion, using enterprise digital transformation as an example of technology-enabled innovations. We specify four innovation characteristics (relative advantage, compatibility, costs and security concern) and four contextual factors (technology competence, organization size, competitive pressure and partner readiness) as determinants of post-adoption usage, and postulate usage as an intermediate link to impact on firm performance. We test the proposed model using a dataset of 1415 companies from six European countries. We find that the innovation needs to be used extensively in value-chain activities before its impact can be realized. Among the innovation characteristics, we find that compatibility is the strongest driver, and security concern outweighs cost as a usage inhibitor. Among the contextual variables, technology competence, partner readiness and competitive pressure significantly drive e-business usage, and the structural inertia of large firms tends to slow down its penetration. Collectively, these results indicate that innovation diffusion can be better understood by including both innovation characteristics and contextual factors, whereas earlier literature has traditionally treated the two separately. Finally, we evaluate an international dimension among European countries and tease out important boundary conditions that would not have been evident in a single-country dataset. Our results show that careful attention must be paid to the economic and regulatory factors that may result in uneven innovation diffusion even among developed European countries.

Proceedings ArticleDOI
23 Apr 2006
TL;DR: A novel Compound TCP (CTCP) approach, which is a synergy of delay-based and loss-based approach, and provides very good bandwidth scalability with improved RTT fairness, and at the same time achieves good TCP-fairness, irrelevant to the windows size is proposed.
Abstract: Many applications require fast data transfer over high speed and long distance networks. However, standard TCP fails to fully utilize the network capacity due to the limitation in its conservative congestion control (CC) algorithm. Some works have been proposed to improve the connection 鈂s throughput by adopt- ing more aggressive loss-based CC algorithms. These algorithms, although can effectively improve the link utilization, have the weakness of poor RTT fairness. Further, they may severely de- crease the performance of regular TCP flows that traverse the same network path. On the other hand, pure delay-based ap- proaches that improve the throughput in high-speed networks may not work well when the traffic is mixed with both delay- based and greedy loss-based flows. In this paper, we propose a novel Compound TCP (CTCP) approach, which is a synergy of delay-based and loss-based approach. Specifically, we add a scal- able delay-based component into the standard TCP Reno conges- tion avoidance algorithm (a.k.a., the loss-based component). The sending rate of CTCP is controlled by both components. This new delay-based component can rapidly increase sending rate when network path is under utilized, but gracefully retreat in a busy network when bottleneck queue is built. Augmented with this delay-based component, CTCP provides very good bandwidth scalability with improved RTT fairness, and at the same time achieves good TCP-fairness, irrelevant to the windows size. We developed an analytical model of CTCP and implemented it on the Windows operating system. Our analysis and experiment results verify the properties of CTCP.

Journal ArticleDOI
TL;DR: The authors examined how accounting quality relates to firm-level capital investment efficiency and found that higher quality accounting enhances investment efficiency by reducing information asymmetry between managers and outside suppliers of capital, and that this effect should be stronger in economies where financing is largely provided through arm'slength transactions compared with countries where creditors supply more capital.
Abstract: This study examines how accounting quality relates to firm‐level capital investment efficiency. Our first hypothesis is that higher quality accounting enhances investment efficiency by reducing information asymmetry between managers and outside suppliers of capital. Our second hypothesis is that this effect should be stronger in economies where financing is largely provided through arm's‐length transactions compared with countries where creditors supply more capital. Our results are consistent with these hypotheses both across and within countries. They are robust to alternative econometric specifications, different measures of accounting quality and investment‐cash flow sensitivity, and numerous control variables.

Journal ArticleDOI
TL;DR: This research has been supported by grants from the CISE/IIS/CSS Division of the U.S. National Science Foundation and the NSF Industry/University Cooperative Research Center to the Center for Research on Information Technology and Organizations (CRITO) at the University of California, Irvine.
Abstract: As firms seek to improve coordination through the use of electronic interorganizational systems (IOS), open standards are becoming increasingly important. To better understand the process of standards diffusion, we investigate firms' migration from proprietary or less-open IOS (i.e., electronic data interchange or EDI) to open-standard IOS (i.e., the Internet). Theoretical work in economics suggests that network effects are a determinant of network adoption, yet the extant literature falls short of empirical testing of the theory. We develop a conceptual model that features network effects, expected benefits, and adoption costs as prominent antecedents. We examine the model on a large dataset of 1,394 firms. The empirical results demonstrate the significant impacts of network effects on open-standard IOS adoption. We find that adoption costs are a significant barrier to open-standard IOS adoption, but EDI users and nonusers treat this very differently: EDI users are much more sensitive to the costs of switching to the new standard. This finding illustrates that experience with older standards may create switching costs and make it difficult to shift to open and potentially better standards, a phenomenon called "excess inertia" in technology change. Further testing the underlying factors that contribute to network effects and adoption costs, we find that trading community influence is a key driver of network effects, while managerial complexity, as opposed to financial costs, is a key determinant of adoption costs. Overall we believe that this study, based on a rigorous empirical analysis of a unique international dataset, provides valuable insights into a set of key factors that influence standards diffusion.

Journal ArticleDOI
01 Dec 2006-Carbon
TL;DR: In this paper, a new method was developed to chemically functionalize multi-walled carbon nanotubes (MWCNTs) based on silanization reaction for use as the reinforcement for polymer matrix composites.

Journal ArticleDOI
TL;DR: In this article, the authors examined the relation between the stock price synchronicity and analyst activity in emerging markets and found that securities which are covered by more analysts incorporate greater (lesser) market-wide (firm-specific) information.

Journal ArticleDOI
TL;DR: Aggregation in poor solvents and complexation with calf thymus DNA and bovine serum albumin turn "on" the fluorescence of tetraphenylethylene derivatives, due to the restriction of intra-molecular rotations of the dyes in the aggregates and complexes.

Journal ArticleDOI
TL;DR: In this paper, a method with an accurate control of threshold voltages of AlGaN/GaN high-electron mobility transistors (HEMTs) using a fluoride-based plasma treatment was presented.
Abstract: This paper presents a method with an accurate control of threshold voltages (Vth) of AlGaN/GaN high-electron mobility transistors (HEMTs) using a fluoride-based plasma treatment. Using this method, the Vth of AlGaN/GaN HEMTs can be continuously shifted from -4 V in a conventional depletion-mode (D-mode) AlGaN/GaN HEMT to 0.9 V in an enhancement-mode AlGaN/GaN HEMT. It was found that the plasma-induced damages result in a mobility degradation of two-dimensional electron gas. The damages can be repaired and the mobility can be recovered by a post-gate annealing step at 400 degC. At the same time, the shift in Vth shows a good thermal stability and is not affected by the post-gate annealing. The enhancement-mode HEMTs show a performance (transconductance, cutoff frequencies) comparable to the D-mode HEMTs. Experimental results confirm that the threshold-voltage shift originates from the incorporation of F ions in the AlGaN barrier. In addition, the fluoride-based plasma treatment was also found to be effective in lowering the gate-leakage current, in both forward and reverse bias regions. A physical model of the threshold voltage is proposed to explain the effects of the fluoride-based plasma treatment on AlGaN/GaN HEMTs

Journal ArticleDOI
TL;DR: The findings indicate that content relevance, self reference, and goal specificity affect the attention, cognitive processes, and decisions of web users in various ways and are found to be receptive to personalized content and find it useful as a decision aid.
Abstract: Personalized information technology services have become a ubiquitous phenomenon. Companies worldwide are using the web to provide personalized offerings and unique experiences to their customers. While there is a lot of hype about delivering personalized services over the web, little is known about the effectiveness of web personalization and the link between the IT artifact (the personalization agent) and the effects it exerts on a user's information processing and decision making. To address the impact of personalized content, this article theoretically develops and empirically tests a model of web personalization. The model is grounded on social cognition and consumer research theories adapted to the peculiar features of web personalization. The influence of a personalization agent is mediated by two variables: content relevance and self reference. Hypotheses generated from the model are empirically tested in a laboratory experiment and a field study. The findings indicate that content relevance, self reference, and goal specificity affect the attention, cognitive processes, and decisions of web users in various ways. Also, users are found to be receptive to personalized content and find it useful as a decision aid. Theoretical and practical implications of the findings are discussed.

Journal ArticleDOI
TL;DR: This paper analyzed the development of the National Innovation Systems (NIS) concept, examining how the formal body of codified NIS knowledge was produced, developed and spread, and how it is used.

Journal ArticleDOI
TL;DR: A kinase/phosphatase switch is used to control the phosphorylation and dephosphorylation of the hydrogelator and to regulate the formation of supramolecular hydrogels, which promises a new way to design and construct biomaterials.
Abstract: We have designed and synthesized a new hydrogelator Nap−FFGEY (1), which forms a supramolecular hydrogel. A kinase/phosphatase switch is used to control the phosphorylation and dephosphorylation of the hydrogelator and to regulate the formation of supramolecular hydrogels. Adding a kinase to the hydrogel induces a gel−sol phase transition in the presence of adenosine triphosphates (ATP) because the tyrosine residue is converted into tyrosine phosphate by the kinase to give a more hydrophilic molecule of Nap−FFGEY−P(O)(OH)2 (2); treating the resulting solution with a phosphatase transforms 2 back to 1 and restores the hydrogel. Electron micrographs of the hydrogels indicate that 1 self-assembles into nanofibers. Subcutaneous injection of 2 in mice shows that 80.5 ± 1.2% of 2 turns into 1 and results in the formation of the supramolecular hydrogel of 1 in vivo. This simple biomimetic approach for regulating the states of supramolecular hydrogels promises a new way to design and construct biomaterials.

Journal ArticleDOI
TL;DR: The aim of this study was to compare the effects of problem‐based learning and lecturing approaches on the development of students' critical thinking.
Abstract: Background Educational approaches are thought to have facilitative or hindering effects on students' critical thinking development. The aim of this study was to compare the effects of problem-based learning (PBL) and lecturing approaches on the development of students' critical thinking. Methods All 79 Year 1 undergraduate nursing students at a university in Hong Kong were randomly assigned to 1 of 2 parallel courses delivered by either PBL (n = 40) or lecturing (n = 39) over 1 academic year. The primary outcome measure was students' critical thinking disposition as measured by the California Critical Thinking Disposition Inventory (CCTDI). Individual interviews were also conducted to elicit the students' perceptions of their learning experience. Data were collected at 4 timepoints spanning 3 years. Results The overall CCTDI and subscale scores for the PBL group were not significantly different from those of the lecture group at the first timepoint (pretest). Compared with lecture students, PBL students showed significantly greater improvement in overall CCTDI (P = 0.0048), Truthseeking (P = 0.0008), Analyticity (P = 0.0368) and Critical Thinking Self-confidence (P = 0.0342) subscale scores from the first to the second timepoints; in overall CCTDI (P = 0.0083), Truthseeking (P = 0.0090) and Analyticity (P = 0.0354) subscale scores from the first to the third timepoints; and in Truthseeking (P = 0.0173) and Systematicity (P = 0.0440) subscale scores from the first to the fourth timepoints. Conclusions There were significant differences in the development of students' critical thinking dispositions between those who undertook the PBL and lecture courses, respectively.

Journal ArticleDOI
TL;DR: In this paper, the authors developed an approach to relate the travel time variability due to stochastic network link capacity variations with travelers' risk aversive route choice behaviors, and formulated a multi-class mixed-equilibrium mathematical program to capture the route choice behavior of travelers with heterogeneous risk aversions or requirements on punctual arrivals.
Abstract: Empirical studies have suggested that travel time reliability plays an important role in travelers’ route choice behavior. This study develops an approach to relate the travel time variability due to stochastic network link capacity variations with travelers’ risk aversive route choice behaviors. We postulate that travelers acquire the variability of route travel times based on past experiences and factor such variability into their route choice consideration in the form of a travel time budget. This travel time budget varies with individuals and trip purposes and is related to the requirement on punctual arrivals. Moreover, all travelers want to minimize their travel time budgets. We formulate a multi-class mixed-equilibrium mathematical program to capture the route choice behaviors of travelers with heterogeneous risk aversions or requirements on punctual arrivals. Such an understanding has important implications on strengthening critical network links. This study then conducts numerical studies to illustrate its properties.


Journal ArticleDOI
TL;DR: In this paper, the authors examine how co-opetition affects firms' competitive behavior, and propose that differential structural positions among firms in a co-competitive network reflect resource asymmetries among them.

Journal ArticleDOI
TL;DR: In this article, the authors investigate why individual stocks become more volatile over the 1976-2000 period, during which quarterly accounting data are available at the firm level, and investigate the relationship between stock return volatility and corporate earnings.
Abstract: We investigate why individual stocks become more volatile over the 1976–2000 period, during which quarterly accounting data are available at the firm level. On average, corporate earnings have deteriorated and their volatilities have increased over the sample period. This is more evident for newly listed stocks than for existing stocks. The stock return volatility is negatively related to the return‐on‐equity and positively related to the volatility of the return‐on‐equity in cross‐sections. The upward trend in average stock return volatility is fully accounted for by the downward trend in the return‐on‐equity and the upward trend in the volatility of the return‐on‐equity.

Journal ArticleDOI
TL;DR: In this article, the influence of the mixture of polypropylene fiber and lime on the engineering properties of a clay-ey soil was investigated and analyzed through scanning electron microscopy (SEM) analysis of the specimens after shearing.

Proceedings ArticleDOI
23 Apr 2006
TL;DR: Statistics prove that this design is scalable and robust, and it is believed that the wide deployment of AnySee will soon benefit many more Internet users as it outperforms previous schemes in resource utilization and the QoS of streaming services.
Abstract: Efficient and scalable live-streaming overlay construction has become a hot topic recently. In order to improve the performance metrics, such as startup delay, source-to-end delay, and playback continuity, most previous studies focused on intra-overlay optimization. Such approaches have drawbacks including low resource utilization, high startup and source-to-end delay, and unreasonable resource assignment in global P2P networks. Anysee is a peer-to-peer live streaming system and adopts an inter-overlay optimization scheme, in which resources can join multiple overlays, so as to (1) improve global resource utilization and distribute traffic to all physical links evenly; (2) assign resources based on their locality and delay; (3) guarantee streaming service quality by using the nearest peers, even when such peers might belong to different overlays; and (4) balance the load among the group members. We compare the performance of our design with existing approaches based on comprehensive trace driven simulations. Results show that AnySee outperforms previous schemes in resource utilization and the QoS of streaming services. AnySee has been implemented as an Internet based live streaming system, and was successfully released in the summer of 2004 in CERNET of China. Over 60,000 users enjoy massive entertainment programs, including TV programs, movies, and academic conferences. Statistics prove that this design is scalable and robust, and we believe that the wide deployment of AnySee will soon benefit many more Internet users.

Journal ArticleDOI
TL;DR: In this review knowledge about antifouling compounds produced by marine bacteria and diatoms are summarised and evaluated and future research directions are highlighted.
Abstract: Development of microbial biofilms and the recruitment of propagules on the surfaces of man-made structures in the marine environment cause serious problems for the navies and for marine industries around the world. Current antifouling technology is based on the application of toxic substances that can be harmful to the natural environment. For this reason and the global ban of tributyl tin (TBT), there is a need for the development of "environmentally-friendly" antifoulants. Marine microbes are promising potential sources of non-toxic or less-toxic antifouling compounds as they can produce substances that inhibit not only the attachment and/or growth of microorganisms but also the settlement of invertebrate larvae and macroalgal spores. However, so far only few antilarval settlement compounds have been isolated and identified from bacteria. In this review knowledge about antifouling compounds produced by marine bacteria and diatoms are summarised and evaluated and future research directions are highlighted.

Journal ArticleDOI
TL;DR: This article highlights several unique aspects of WSNs, and describes the basic design criteria and challenges of transport protocols, including energy-efficiency, quality of service, reliability, and congestion control.
Abstract: In this article we present a survey of transport protocols for wireless sensor networks (WSNs). We first highlight several unique aspects of WSNs, and describe the basic design criteria and challenges of transport protocols, including energy-efficiency, quality of service, reliability, and congestion control. We then provide a summary and comparison of existing transport protocols for WSNs. Finally, we discuss several open research problems.