Showing papers by "National University of Singapore published in 1994"

Verb semantics and lexical selection

Abstract: This paper will focus on the semantic representation of verbs in computer systems and its impact on lexical selection problems in machine translation (MT). Two groups of English and Chinese verbs are examined to show that lexical selection must be based on interpretation of the sentences as well as selection restrictions placed on the verb arguments. A novel representation scheme is suggested, and is compared to representations with selection restrictions used in transfer-based MT. We see our approach as closely aligned with knowledge-based MT approaches (KBMT), and as a separate component that could be incorporated into existing systems. Examples and experimental results will show that, using this scheme, inexact matches can achieve correct lexical selection.

A brain serine/threonine protein kinase activated by Cdc42 and Rac1.

Abstract: A new brain serine/threonine protein kinase may be a target for the p21ras-related proteins Cdc42 and Rac1. The kinase sequence is related to that of the yeast protein STE20, implicated in pheromone-response pathways. The kinase complexes specifically with activated (GTP-bound) p21, inhibiting p21 GTPase activity and leading to kinase autophosphorylation and activation. Autophosphorylated kinase has a decreased affinity for Cdc42/Rac, freeing the p21 for further stimulatory activities or downregulation by GTPase-activating proteins. This bimolecular interaction provides a model for studying p21 regulation of mammalian phosphorylation signalling pathways.

Institutional Factors in Information Technology Innovation

Abstract: Innovation in information technology is well established in developed nations; newly industrializing and developing nations have been creating governmental interventions to accelerate IT innovation within their borders. The lack of coherent policy advice for creating government policy for IT innovation signals a shortfall in research understanding of the role of government institutions, and institutions more broadly, in IT innovation. This paper makes three points. First, long-established intellectual perspectives on innovation from neoclassical economics and organization theory are inadequate to explain the dynamics of actual innovative change in the IT domain. A broader view adopted from economic history and the new institutionalism in sociology provides a stronger base for understanding the role of institutions in IT innovation. Second, institutional intervention in IT innovation can be constructed at the intersection of the influence and regulatory powers of institutions and the ideologies of supply-push and demand-pull models of innovation. Examples of such analysis are provided. Third, institutional policy formation regarding IT innovation is facilitated by an understanding of the multifaceted role of institutions in the innovative process, and on the contingencies governing any given institution/innovation mix.

Integrating case study and survey research methods: an example in information systems

Abstract: The case for combining research methods generally, and more specifically that for combining qualitative and quantitative methods, is strong. Yet, research designs that extensively integrate both fieldwork (e.g. case studies) and survey research are rare. Moreover, some journals tend tacitly to specialise by methodology thereby encouraging purity of method. The multi-method model of research, while not new, has not been appreciated. In this respect it is useful to describe its usage through example. By reference to a recently completed study of IS consultant engagement success factors this paper presents an analysis of the benefits of integrating case study and survey research methods. The emphasis is on the qualitative case study method and how it can complement more quantitative survey research. Benefits are demonstrated through specific examples from the reference study.

Verb Semantics and Lexical Selection

Abstract: This paper will focus on the semantic representation of verbs in computer systems and its impact on lexical selection problems in machine translation (MT). Two groups of English and Chinese verbs are examined to show that lexical selection must be based on interpretation of the sentence as well as selection restrictions placed on the verb arguments. A novel representation scheme is suggested, and is compared to representations with selection restrictions used in transfer-based MT. We see our approach as closely aligned with knowledge-based MT approaches (KBMT), and as a separate component that could be incorporated into existing systems. Examples and experimental results will show that, using this scheme, inexact matches can achieve correct lexical selection.

Content based video indexing and retrieval

Abstract: Video management tools and techniques are based on pixels rather than perceived content. Thus, state-of-the-art video editing systems can easily manipulate such things as time codes and image frames, but they cannot "know," for example, what a basketball is. Our research addresses four areas of content-based video management. >

A new Smith predictor for controlling a process with an integrator and long dead-time

Abstract: A new Smith predictor for control of a process with an integrator and long dead-time is proposed in this note. The controller decouples the setpoint response from the load response. This simplifies both design and tuning. Simulation results obtained by controlling a typical process show that the new controller has superior performance compared to previous algorithms. >

The international law on foreign investment

Abstract: Following the Trans-Pacific Partnership (TPP) and Transatlantic Trade and Investment Partnership (TTIP), the demonstrations against investor-state arbitration and the wide discussion during the 2016 US presidential election, the climate surrounding foreign investment law is one of controversy and change, and with implications for human rights and environmental protection, foreign investment law has gained widespread public attention and visibility. Addressing the pressing need to examine foreign investment law in the context of public international law, the role of the multinational corporation in foreign investment and issues of liability for environmental and other damage, this new edition analyses contractual and treaty-based methods of investment protection and examines the effectiveness of bilateral and regional investment treaties. By offering thought-provoking analysis of the law in historical, political and economic contexts, this fully updated edition of Sornarajah's classic text captures leading trends and charts the possible course of future developments. Suitable for postgraduate and undergraduate students, The International Law on Foreign Investment is essential reading for anyone specialising in the law of foreign investments.

Identification and Assessment Of Known And Novel Human Papillomaviruses by Polymerase Chain Reaction Amplification, Restriction Fragment Length Polymorphisms, Nucleotide Sequence, and Phylogenetic Algorithms

Abstract: The identification and taxonomy of papillomaviruses has become increasingly complex, as approximately 70 human papillomavirus (HPV) types have been described and novel HPV genomes continue to be identified. Methods and corresponding DNA sequence data bases were designed for the reliable identification of mucosal HPV genomes from clinical specimens. HPVs are identified by the amplification of a fragment of the L1 region by consensus primer polymerase chain reaction (PCR) and subsequent hybridization or restriction fragment length polymorphism analysis. L1 PCR fragments may be further characterized by nucleotide sequencing. Conservation of 30 (of 151) predicted amino acids identifies HPV genomic fragments, and nucleotide sequence alignments allow calculation of their phylogenetic relatedness. Sequence differences > 10% from any known HPV type suggest a novel HPV type. Phylogenetic relationships with known HPV types may permit predictions of biology. With these criteria, 10 PCR fragments were identified that would qualify as new genital HPV types after complete genomic isolation.

Isolation and culture of inner cell mass cells from human blastocysts.

Abstract: Totipotent non-committed inner cell mass (ICM) cells from human blastocyts, if demonstrated to be capable of proliferating in vitro without differentiation, will have several beneficial uses, not only in the treatment of neurodegenerative and genetic disorders, but also as a model in studying the events involved in embryogenesis and genomic manipulation. Nine patients admitted to an in-vitro fertilization programme donated 21 spare embryos for this study. All 21 embryos were grown from the 2-pronuclear until blastocyst stages on a human tubal epithelial monolayer in commercial Earle's medium (Medicult, Denmark) supplemented with 10% human serum. The medium was changed after blastocyst formation to Chang's medium supplemented with 1000 units/ml of human leukaemia inhibitory factor (HLIF) and the embryos left undisturbed for 72 h to allow the hatched ICM and trophoblast to attach to the feeder monolayer. Nineteen of the 21 embryos from nine patients produced healthy ICM lumps which could be separated and grown in vitro. Two of the lumps differentiated into fibroblasts while the remaining 17 (eight patients) produced cells with typical stem cell-like morphology, were alkaline phosphatase positive and could be maintained for two passages. It was possible to retain the stem cell-like morphology, alkaline phosphatase positiveness and normal karyotype through the two passages in all of them using repeated doses of HLIF every 48 to 72 h. This is the first report on the successful isolation of human ICM cells and their continued culture for at least two passages in vitro.

Exploring Language Effects in Ethnic Advertising: A Sociolinguistic Perspective

Abstract: The authors apply sociolinguistic theories of accommodation to investigate how consumers in a minority subculture respond to the use of their ethnic language in advertising. Specifically, Hispanic consumers' responses to the varying degrees of Spanish-language usage in print advertising were examined. It was found that the effects of Spanish usage in advertising can be usefully explained by accommodation theory. Spanish-language advertising increased Hispanic consumers' perception of advertiser sensitivity to Hispanic culture and people, and this perception in turn enhanced affect toward the advertisements. Yet, after controlling for perceived advertiser sensitivity, it was also found that advertising exclusively in Spanish decreased affect toward the advertisement. This finding may be interpreted to mean that though Spanish-language advertising appears to signal solidarity with the Hispanic community, exclusive use of Spanish in advertising may arouse Hispanic insecurities about language usage. Implications for future research and theory on language choice and usage in communication to consumer subcultures are discussed.

Kohonen neural networks for optimal colour quantization

Abstract: We present a self-organizing Kohonen neural network for quantizing colour graphics images. The network is compared with existing algorithmic methods for colour quantization. It is shown experimentally that, by adjusting a quality factor, the network can produce images of much greater quality with longer running times, or slightly better quality with shorter running times than the existing methods. This confounds the frequent observation that Kohonen neural networks are necessarily slow. The continuity of the colour map produced can be exploited for further image compression, or for colour palette editing.

Overexpression of E2F-1 in rat embryo fibroblasts leads to neoplastic transformation.

Abstract: The transcription factor E2F has been implicated in controlling the activation of multiple genes associated with cell proliferation. E2F-1, which is a component of E2F, can promote oncogenesis when transfected into REF cells. The transformation caused by E2F-1 correlates with constitutive overexpression of the transgene, increased transcription of E2F-dependent genes and the enhancement of two E2F DNA binding complexes containing the retinoblastoma susceptibility gene product (Rb) and E2F-1. The oncogenic potential of E2F-1 is dependent on functional DNA binding and transactivation domains but does not require the ability to interact directly with Rb. These findings provide the first direct evidence that sustained unregulated expression of E2F-1 can lead to the loss of cell proliferation control and that E2F-1 is a key component in cell cycle control.

Electromagnetic dyadic Green's function in spherically multilayered media

Abstract: A spectral-domain dyadic Green's function constructed for defining the electromagnetic fields in spherically multilayered media is considered by assuming that distribution and location of current sources are arbitrary. The scattering dyadic Green's function in each layer is constructed in terms of the spherical vector wave functions by applying the method of scattering superposition. The coefficients of the scattering dyadic Green's functions, based on the coupling recurrence equations satisfied by the coefficient matrix, are derived and expressed in terms of the equivalent reflection and transmission coefficients. The general solution has been applied to specific geometries, e,g., two-, three- and four-layered media that are frequently employed to model the practical problems, and the coefficients of the scattering dyadic Green's functions are presented. >

A survey of partial difference sets

Abstract: LetG be a finite group of order ν. Ak-element subsetD ofG is called a (ν,k, λ, μ)-partial difference set if the expressionsgh −1, forg andh inD withg≠h, represent each nonidentity element inD exactly λ times and each nonidentity element not inD exactly μ times. Ife∉D andg∈D iffg −1∈D, thenD is essentially the same as a strongly regular Cayley graph. In this survey, we try to list all important existence and nonexistence results concerning partial difference sets. In particular, various construction methods are studied, e.g., constructions using partial congruence partitions, quadratic forms, cyclotomic classes and finite local rings. Also, the relations with Schur rings, two-weight codes, projective sets, difference sets, divisible difference sets and partial geometries are discussed in detail.

Automatic parsing of news video

Abstract: Video content parsing is possible when one has an a priori model of a video's structure based on domain knowledge. This paper presents work on using domain knowledge to parse content of news video programs. Approaches to locating and identifying frame structure models based on temporal and spatial structure of news video data, along with algorithms to apply these models in parsing news video, have been developed and are presented in detail in this paper. Experimental results are also discussed in detail to evaluate the approaches and algorithms. Finally, proposals for future work are summarized. >

The human papillomavirus type 16 E2 transcription factor binds with low cooperativity to two flanking sites and represses the E6 promoter through displacement of Sp1 and TFIID.

Abstract: The E6 promoters of all genital human papillomaviruses have a characteristic alignment of transcription factor binding sites. Activation of the basic transcription complex at the TATA box depends upon a sequence-aberrant Sp1 site. Repression of E6 promoters is achieved by two binding sites for the viral E2 protein positioned between the Sp1 site and the TATA box. We have purified the human papillomavirus type 16 E2 protein after expression in Escherichia coli and studied its binding and repression properties with oligonucleotides representing the homologous promoter sequences. A Kd value of 3 x 10(-10) M indicated binding properties expected for a native protein. We found low cooperativity in the binding of two E2 dimers to flanking sites, both when these sites were separated by 3 nucleotides, as in the natural promoter, and when they were further apart. E2 protein, bound close to the distal Sp1 site, displaced the Sp1 factor even when the aberrant sequence was replaced by a typical Sp1 core recognition site. The high affinity of E2 protein for its binding site even led to Sp1 displacement at concentrations of E2 protein nearly 2 orders of magnitude lower than those of Sp1. Functional analyses of mutated E6 promoter sequences showed repression by this distal E2 binding site in the complete absence of binding to the proximal E2 binding site. From our findings and observations published by others, we conclude that each of the E2 binding sites in the E6 promoter of genital human papillomaviruses plays a separate role by displacing the transcription factors Sp1 and TFIID. Images

Efficient and Rapid Affinity Purification of Proteins Using Recombinant Fusion Proteases

Abstract: In the affinity purification of recombinant fusion proteins, the rate-limiting step is usually the efficient proteolytic cleavage and removal of the affinity tail and the protease from the purified recombinant protein. We have developed a rapid, convenient and efficient method of affinity purification which can overcome this limitation. In one example of the method, the protease 3C from a picornavirus (3Cpro), which cleaves specific sequences containing a minimum of 6-7 amino acids, has been expressed as a fusion with glutathione S-transferase. The resultant recombinant 'fusion protease' cleaves fusion proteins bearing (from the amino-terminus) the same affinity tail as the fusion protease, a 3Cpro cleavage recognition site, and the recombinant protein of interest. The recombinant protein is purified in a single chromatographic step which removes both the affinity tail and the fusion protease. The advantages over existing methods include much improved specificity of proteolytic cleavage, complete removal of the protease and the affinity tail in one step, and the option of adding any desired amount of fusion protease to ensure efficient cleavage. The potential flexibility of the method is shown by the use of various affinity tails and alternative fusion proteases.

An Examination of the Antecedents of Subjective Career Success Among a Managerial Sample in Singapore

Abstract: Data obtained with a questionnaire instrument from managerial employees (N = 200) in Singapore were used to examine some antecedents of subjective career success. The choice of antecedents was informed by recent calls to place research on career issues in the context of an individual's life roles. Confirmatory factor analysis (LISREL VII) was used to examine the one-factor and three-factor models hypothesized to underlie the subjective career success data. The results revealed a three-factor model to have adequate fit statistics - financial and hierarchical success, and career satisfaction. The antecedent sets of human capital, work values, family and structural or work variables accounted for over 40% of the explained variance in each career success dimension. While the career success dimensions were influenced by different variables, individual-organizational value congruity, quality of parental role and internal labor market emerged as consistent antecedents of the career success dimensions. The patter...

On the equivalence of McEliece's and Niederreiter's public-key cryptosystems

Abstract: It is shown that McEliece's and Niederreiter's public-key cryptosystems are equivalent when set up for corresponding choices of parameters. A security analysis for the two systems based on this equivalence observation, is presented. >

Investigation of outbreaks of a novel disease, ‘Sleepy Grouper Disease’, affecting the brown‐spotted grouper, Epinephelus tauvina Forskal

Abstract: . A novel disease affecting the brown-spotted grouper, Epinephelus tauvina Forskal, described here as Sleepy Grouper Disease1 (SGD), resulted in significant economic losses in some Singaporean marine net-cage farms from April to August 1992. Investigations suggested that the aetiological agent was a virus, probably introduced with imported groupers. The virus was provisionally identified as an iridovirus on morphological evidence. The disease caused extreme lethargy in affected fish with few visible external signs. Mortalities either occurred gradually over the week from onset of clinical signs, or over a shorter period and in large numbers if fish were stressed. Consistent tissue changes were seen by light microscopy in the spleen, heart and kidney of affected fish. Electron microscopy showed viral particles associated with damage to cell organelles. In an experimental infection, apparently healthy fish cohabiting with an infected fish developed similar lesions and died. The significance of SGD in grouper culture is discussed.