Showing papers by "National University of Singapore published in 1998"
Proceedings Article•
27 Aug 1998TL;DR: The integration is done by focusing on mining a special subset of association rules, called class association rules (CARs), and shows that the classifier built this way is more accurate than that produced by the state-of-the-art classification system C4.5.
Abstract: Classification rule mining aims to discover a small set of rules in the database that forms an accurate classifier. Association rule mining finds all the rules existing in the database that satisfy some minimum support and minimum confidence constraints. For association rule mining, the target of discovery is not pre-determined, while for classification rule mining there is one and only one predetermined target. In this paper, we propose to integrate these two mining techniques. The integration is done by focusing on mining a special subset of association rules, called class association rules (CARs). An efficient algorithm is also given for building a classifier based on the set of discovered CARs. Experimental results show that the classifier built this way is, in general, more accurate than that produced by the state-of-the-art classification system C4.5. In addition, this integration helps to solve a number of problems that exist in the current classification systems.
2,479 citations
TL;DR: An example-based learning approach for locating vertical frontal views of human faces in complex scenes and shows empirically that the distance metric adopted for computing difference feature vectors, and the "nonface" clusters included in the distribution-based model, are both critical for the success of the system.
Abstract: We present an example-based learning approach for locating vertical frontal views of human faces in complex scenes. The technique models the distribution of human face patterns by means of a few view-based "face" and "nonface" model clusters. At each image location, a difference feature vector is computed between the local image pattern and the distribution-based model. A trained classifier determines, based on the difference feature vector measurements, whether or not a human face exists at the current image location. We show empirically that the distance metric we adopt for computing difference feature vectors, and the "nonface" clusters we include in our distribution-based model, are both critical for the success of our system.
2,013 citations
TL;DR: Results indicate that although caspase-3 is not essential for TNF- or staurosporine-induced apoptosis, it is required for DNA fragmentation and some of the typical morphological changes of cells undergoing apoptosis.
1,957 citations
TL;DR: The ability of aniline polymers to exist in a large number of intrinsic redox states makes them a unique and interesting class of polymeric materials as mentioned in this paper, and a number of fine reviews on the synthesis, physicochemical and electrochemical properties of the polymer have also appeared during this period.
1,407 citations
TL;DR: The authors provide an overview of recent empirical research on patterns of cross-country growth, focusing more directly on questions like, Why do some countries grow faster than others? It is this changed focus that, in their view, has motivated going beyond the neoclassical growth model.
Abstract: We provide an overview of recent empirical research on patterns of cross-country growth. The new empirical regularities considered differ from earlier ones, e.g. the well-known Kaldor stylized facts. The new research no longer makes production function accounting a central part of the analysis. Instead, attention shifts more directly to questions like, Why do some countries grow faster than others? It is this changed focus that, in our view, has motivated going beyond the neoclassical growth model.
1,171 citations
TL;DR: By expressing PVY and CMV‐encoded proteins in a PVX vector, it is shown that the viral suppressors of gene silencing are the HCPro of PVy and the 2b protein of CMV.
Abstract: Post-transcriptional gene silencing (PTGS) of a green fluorescent protein (GFP) transgene is suppressed in Nicotiana benthamiana plants infected with potato virus Y (PVY) or with cucumber mosaic virus (CMV), but not in plants infected with potato virus X (PVX). By expressing PVY and CMV-encoded proteins in a PVX vector we have shown that the viral suppressors of gene silencing are the HCPro of PVY and the 2b protein of CMV. The HCPro acts by blocking the maintenance of PTGS in tissues where silencing had already been set, whereas the 2b protein prevents initiation of gene silencing at the growing points of the plants. Combined with previous findings that viruses are both activators and targets of PTGS, these data provide compelling evidence that PTGS represents a natural mechanism for plant protection against viruses.
1,099 citations
University of Oregon1, New York University2, University of California, San Francisco3, Howard Hughes Medical Institute4, National University of Singapore5, École Normale Supérieure6, University of Bath7, Harvard University8, Brigham and Women's Hospital9, Uppsala University10, Washington University in St. Louis11
TL;DR: This zebrafish gene map will facilitate molecular identification of mutated zebra-fish genes, which can suggest functions for human genes known only by sequence, and is likely that two polyploidization events occurred prior to the divergence of fish and mammal lineages.
Abstract: In chordate phylogeny, changes in the nervous system, jaws, and appendages transformed meek filter feeders into fearsome predators. Gene duplication is thought to promote such innovation. Vertebrate ancestors probably had single copies of genes now found in multiple copies in vertebrates and gene maps suggest that this occurred by polyploidization. It has been suggested that one genome duplication event occurred before, and one after the divergence of ray-finned and lobe-finned fishes. Holland et al., however, have argued that because various vertebrates have several HOX clusters, two rounds of duplication occurred before the origin of jawed fishes. Such gene-number data, however, do not distinguish between tandem duplications and polyploidization events, nor whether independent duplications occurred in different lineages. To investigate these matters, we mapped 144 zebrafish genes and compared the resulting map with mammalian maps. Comparison revealed large conserved chromosome segments. Because duplicated chromosome segments in zebrafish often correspond with specific chromosome segments in mammals, it is likely that two polyploidization events occurred prior to the divergence of fish and mammal lineages. This zebrafish gene map will facilitate molecular identification of mutated zebrafish genes, which can suggest functions for human genes known only by sequence.
783 citations
TL;DR: The authors of as discussed by the authors argue that concentrated, inherited corporate control impedes growth, and dub this the Canadian disease, and suggest that capital market openness matters for reasons not captured by standard international trade and finance models.
Abstract: Countries in which billionaire heirs' wealth is large relative to G.D.P. grow more slowly, show signs of more political rent-seeking, and spend less on innovation than do other countries at similar levels of development. In contrast, countries in which self-made entrepreneur billionaire wealth is large relative to G.D.P. grow more rapidly and show fewer signs of rent seeking. We argue that this is consistent with wealthy entrenched families' having objectives other than creating public shareholder value. Also, the control pyramids through which they are entrenched give wealthy families preferential access to capital and enhanced lobbying power. Entrenched families also have vested interest in preserving the value of existing capital. To investigate these arguments, we use firm-level Canadian data. Heir-controlled Canadian firms show low industry-adjusted financial performance, labor capital ratios, and R&D spending relative to other firms the same ages and sizes. We argue that concentrated, inherited corporate control impedes growth, and dub this the Canadian disease.' Further research is needed to determine the international incidence of this condition. Finally, heir-controlled Canadian firms' share prices fell relative to those of comparable firms on the news that the Canada-U.S. free trade agreement would be ratified. A key provision of that treaty is capital market openness. Under the treaty, heir-controlled Canadian firms' labor capital ratios rose, while the incidence of heir-control fell. We suggest that openness, especially of capital markets, may mitigate the ill effects of concentrated inherited control. If so, capital market openness matters for reasons not captured by standard international trade and finance models.
682 citations
TL;DR: A decomposition method for factorizing changes in energy demand or gas emissions over time with the advantage of giving perfect decomposition is introduced and may be generally applied in energy and environmental decomposition studies.
682 citations
TL;DR: A novel unrestricted center-biased diamond search (UCBDS) algorithm is proposed which is more efficient, effective, and robust than the previous techniques and consistently faster than the other suboptimal block-matching techniques.
Abstract: The widespread use of block-based interframe motion estimation for video sequence compression in both MPEG and H.263 standards is due to its effectiveness and simplicity of implementation. Nevertheless, the high computational complexity of the full-search algorithm has motivated a host of suboptimal but faster search strategies. A popular example is the three-step search (TSS) algorithm. However, its uniformly spaced search pattern is not well matched to most real-world video sequences in which the motion vector distribution is nonuniformly biased toward the zero vector. Such an observation inspired the new three-step search (NTSS) which has a center-biased search pattern and supports a halfway-stop technique. It is faster on average, and gives better motion estimation as compared to the well-known TSS. Later, the four-step search (4SS) algorithm was introduced to reduce the average case from 21 to 19 search points, while maintaining a performance similar to NTSS in terms of motion compensation errors. We propose a novel unrestricted center-biased diamond search (UCBDS) algorithm which is more efficient, effective, and robust than the previous techniques. It has a best case scenario of only 13 search points and an average of 15.5 block matches. This makes UCBDS consistently faster than the other suboptimal block-matching techniques. This paper also compares the above methods in which both the processing speed and the accuracy of motion compensation are tested over a wide range of test video sequences.
680 citations
TL;DR: In this paper, two inequalities for differentiable convex mappings which are connected with the celebrated Hermite-Hadamard's integral inequality holding for convex functions are given.
TL;DR: Data show specific involvement of the CD95-CD95L system in the anti-cancer activity of resveratrol and highlight the chemotherapeutic potential of this natural product, in addition to its recently reported chemopreventive activity.
TL;DR: In this article, the authors make an attempt to develop a comprehensive literature on outsourcing based on more than 100 published articles, papers and books on the subject, which is indicated by the volume of writings on outsourcing in various scholarly journals, trade publications and popular magazines.
Abstract: Recent times have witnessed a heightened global interest in outsourcing of logistics functions. This is indicated by the volume of writings on the subject in various scholarly journals, trade publications and popular magazines. However, efforts to organize them in an integrated body of knowledge appear to be very limited. Keeping this in view, this paper makes an attempt to develop a comprehensive literature on outsourcing based on more than 100 published articles, papers and books on the subject.
TL;DR: It is suggested that caspase-3 is essential for cleavage of α-fodrin, but dispensable for the cleaved of PARP, Rb, PAK2, DNA-PKcs, gelsolin, and DFF-45 and imply that one or more caspases other than caspasing 2, 3, and 7 is activated and plays a crucial role in the cleaving of these substrates in MCF-7 cells.
TL;DR: In this paper, a two-phase swirl-flow monolithic type reactor was designed to study the kinetics of heterogeneous photocatalytic processes on semiconductor catalysts, and the photomineralization of 4-nitrophenol (4-NP) sensitized by Degussa P25 TiO2 in aqueous solution has been investigated as a function of the following different experimental parameters: initial concentration of pollutant (CS0), light intensity (Ia), partial pressure of oxygen (pO2), catalyst concentration, pH, chloride ion and temperature
TL;DR: In this article, a deposition mechanism is tentatively proposed and discussed for a well-dispersed deposition of Pt clusters on the surface of carbon nanotubes, which can act as specific nucleation sites.
Abstract: Carbon nanotubes can be functionalized by oxidation of HNO3 or H2SO4−HNO3. The latter shows a higher capability in producing a high density of surface functional groups. These groups can act as specific nucleation sites for a well-dispersed deposition of Pt clusters on the surface of carbon nanotubes. These modified carbon nanotube materials were investigated by TEM, XPS, and DRIFT. A deposition mechanism is tentatively proposed and discussed.
TL;DR: It is reported that cyc encodes a transforming growth factor-β (TGF-β)-related intercellular signalling molecule that is similar to mouse nodal and provides an essential non-cell-autonomous signal at gastrulation, leading to induction of the floorplate and ventral brain.
Abstract: Zebrafish cyclops (cyc) mutations cause deficiencies in the dorsal mesendoderm1,2 and ventral neural tube3,4, leading to neural defects and cyclopia5,6. Here we report that cyc encodes a transforming growth factor-β (TGF-β)-related intercellular signalling molecule that is similar to mouse nodal7. cyc is expressed in dorsal mesendoderm at gastrulation and in the prechordal plate until early somitogenesis. Expression reappears transiently in the left lateral-plate mesoderm, and in an unprecedented asymmetric pattern in the left forebrain. Injection of cyc RNA non-autonomously restores sonic hedgehog -expressing cells of the ventral brain and floorplate that are absent in cyc mutants, whereas inducing activities are abolished by cycm294, a mutation of a conserved cysteine in the mature ligand. Our results indicate that cyc provides an essential non-cell-autonomous signal at gastrulation, leading to induction of the floorplate and ventral brain.
Book•
08 Jul 1998TL;DR: This chapter discusses Iterative Learning Control with Non-Standard Assumptions Applied to the Control of Gas-Metal Arc Welding and its Extension to a Class of Nonlinear Systems.
Abstract: List of Figures. List of Tables. Preface. Part I: General Introduction to Iterative Learning Control. 1. A Brief History of Iterative Learning Control S. Arimoto. 2. The Frontiers of Iterative Learning Control Jian-Xin Xu, Zenn Z. Bien. Part II: Property Analysis of Iterative Learning Control. 3. Robustness and Convergence of a PD-type Iterative Learning Controller Hak-Sung Lee, Zeungnam Bien. 4. Ability of Learning Comes from Passivity and Dissipativity of System Dynamics S. Arimoto. 5. On the Iterative Learning Control of Sampled-Data Systems Chiang-Ju Chien. 6. High-Order Iterative Learning Control of Discrete-Time Nonlinear Systems Using Current Iteration Tracking Error Yangquan Chen, et al. Part III: The Design Issues of Iterative Learning Control. 7. Designing Iterative Learning and Repetitive Controllers R.W. Longman. 8. Design of an ILC for Linear Systems with Time-Delay and Initial State Error Kwang-Hyun Park, et al. 9. Design of Quadratic Criterion-Based Iterative Learning Control Kwang Soon Lee, J.H. Lee. 10. Robust ILC with Current Feedback for Uncertain Linear Systems Tae-Yong Doh, Myung Jin Chung. Part IV: Integration of Iterative Learning Control with Other Intelligent Controls. 11. Model Reference Learning Control with a Wavelet Network M. Fukuda, S. Shin. 12. Neural-Based Iterative Learning Control Jin Young Choi, et al. 13. Adaptive Learning Control of Robotic Systems and Its Extension to a Class of Nonlinear Systems B.H. Park, et al. 14. Direct Learning Control of Non-Uniform Trajectories Jian-Xin Xu, Yanbin Song. 15. System Identification and Learning Control M.Q. Phan, J.A. Frueh. Part V: Implementations of Iterative Learning Control Method. 16. Model-Based Predictive Control Combined with Iterative Learning for Batch or Repetitive Processes Kwang Soon Lee, J.H. Lee. 17. Iterative Learning Control with Non-Standard Assumptions Applied to the Control of Gas-Metal Arc Welding K.L. Moore, A. Matheus. 18. Robust Control of Functional Neuromuscular Stimulation System by Discrete-time Iterative Learning Huifang Dou, et al. Index. About the Editors.
TL;DR: Simulation results show that the performance approaches single-user performance even for moderate signal-to-noise ratios, and Iterations of the system are used to improve performance, with dramatic effects.
Abstract: This paper introduces an iterative multiuser receiver for direct sequence code-division multiple access (DS-CDMA) with forward error control (FEC) coding. The receiver is derived from the maximum a posteriori (MAP) criterion for the joint received signal, but uses only single-user decoders. Iterations of the system are used to improve performance, with dramatic effects. Single-user turbo code decoders are utilized as the FEC system and a complexity study is presented. Simulation results show that the performance approaches single-user performance even for moderate signal-to-noise ratios.
TL;DR: This paper examined the conditional heteroscedasticity of the yen-dollar exchange rate and found that the appreciation and depreciation shocks of the Japanese yen against the dollar have similar effects on future volatilities.
Abstract: This paper examines the conditional heteroscedasticity of the yen–dollar exchange rate A model is constructed by extending the asymmetric power autoregressive conditional heteroscedasticity model to a process that is fractionally integrated It is found that, unlike the equity markets, the appreciation and depreciation shocks of the yen against the dollar have similar effects on future volatilities Although the results reject both the stable and the integrated models, our analysis of the response coefficients of the past shocks and the application of the models to the estimation of the capital requirements for trading the currencies show that there are no substantial differences between the fractionally integrated models and the stable models © 1998 John Wiley & Sons, Ltd
TL;DR: In this paper, the effect of coagulation medium, ethanol (10-50%), and water (90-50%) on the morphology of polyvinylidene fluoride (PVDF) hollow fibre membranes was studied using SEM.
TL;DR: In this article, the existence and stability of traveling waves in lattice dynamical systems, in particular in coupled map lattices and in CMLs, was studied, and it was shown that the traveling wave corresponds to a periodic solution of a nonautonomous periodic differential equation.
TL;DR: The prevalence of all types of chronic gastrointestinal symptoms in the general population of Singapore was low compared with those in the West, including reflux-type symptoms, which were more common among Indians than Chinese or Malays.
TL;DR: Seasonal trends of viral respiratory tract infections in the tropics supported by a retrospective survey of laboratory virus isolation, serology and immunofluorescence microscopy in two large general hospitals in Singapore between September 1990 and September 1994.
Abstract: To evaluate the seasonal trends of viral respiratory tract infections in a tropical environment, a retrospective survey of laboratory virus isolation, serology and immunofluorescence microscopy in two large general hospitals in Singapore between September 1990 and September 1994 was carried out. Respiratory tract viral outbreaks, particularly among infants who required hospitalization, were found to be associated mainly with respiratory syncytial (RSV) infections (72%), influenza (11%) and parainfluenza viruses (11%). Consistent seasonal variations in viral infections were observed only with RSV (March-August) and influenza A virus (peaks in June, December-January). The RSV trends were associated with higher environmental temperature, lower relative humidity and higher maximal day-to-day temperature variation. Although the influenza A outbreaks were not associated with meteorological factors, influenza B isolates were positively associated with rainfall. These data support the existence of seasonal trends of viral respiratory tract infections in the tropics.
TL;DR: This paper transforms the berthing problem to a restricted form of the two-dimensional packing problem, uses a graph theoretical representation to capture the problem succinctly, and proposes an effective heuristic for the problem.
TL;DR: By cloning the indeterminate1 gene, it is shown that it encodes a protein with zinc finger motifs, suggesting that the id1 gene product functions as a transcriptional regulator of the floral transition.
TL;DR: In this paper, a critical view of the culturalist explanation for Chinese business success and the inferred disparity between an idealized, static model of the three concepts and that of how guanxi and xinyong are dynamic concepts and how they actually play out in the reality of running a firm are discussed.
Abstract: This chapter focuses on personalism, elaborating on the three key elements—guanxi, xinyong, and personal control. It takes a critical view of the culturalist explanation for Chinese business success and the inferred disparity between an idealized, static model of the three concepts and that of how guanxi and xinyong are dynamic concepts and how they actually play out in the reality of running a firm. The chapter also makes a key distinction of guanxi bases as a necessary prerequisite but not equivalent to guanxi relations, in the process identifying six main guanxi bases—locality/dialect, fictive kinship, kinship, workplace, trade associations and social clubs, and friendship. It suggests that a multiplex of guanxi relations facilitates better business ties than singular strands. The chapter explores the difference between personal trust and systems trust. It stresses the need to consider institutional and environmental elements that may shape the organization of Chinese firms rather than just the organization per se.
TL;DR: In this article, the structure, doping, conductivity and thermal stability of reduced polyaniline (PANI-R) were studied by elemental analysis, FT-i.r., solid-state 13C-NMR, XPS and TGA.
TL;DR: How the search directions for the Nesterov--Todd (NT) method can be computed efficiently and how they can be viewed as Newton directions are discussed and demonstrated.
Abstract: We study different choices of search direction for primal-dual interior-point methods for semidefinite programming problems. One particular choice we consider comes from a specialization of a class of algorithms developed by Nesterov and Todd for certain convex programming problems. We discuss how the search directions for the Nesterov--Todd (NT) method can be computed efficiently and demonstrate how they can be viewed as Newton directions. This last observation also leads to convenient computation of accelerated steps, using the Mehrotra predictor-corrector approach, in the NT framework. We also provide an analytical and numerical comparison of several methods using different search directions, and suggest that the method using the NT direction is more robust than alternative methods.
TL;DR: In this article, the authors argue that despite the accelerated processes of globalization, national boundaries still matter in the decision-making and global reach of capital, and that the notion of a 'borderless' world is more folklore than reality.
Abstract: The globalization of economic activities and transnational corporations (TNCs) has led us to think that we are entering a ‘borderless’ world. Some prophets of globalization argue that it has led to the end of geography. To them, the state has ceased to be an institution capable of exerting influences on the activities of transnational capital, which has also become increasingly ‘placeless’. This paper aims to contest the issue of the alleged end-state discourse of a ‘borderless’ world. It argues that, despite the accelerated processes of globalization, national boundaries still matter in the decision-making and global reach of capital. The notion of a ‘borderless’ world is more folklore than reality. Based on theoretical and empirical literature in international political economy and business studies, the paper offers a dialectical perspective that examines the changing relationship between capital and the state, and the embedded relationship between capital and space in the organization of the global space-economy. Together, both arguments point to the importance of understanding dynamic transformations of the global economy, before considering its globalization tendencies.