pok lim | Chulalongkorn University (original) (raw)
Papers by pok lim
ABSTRACT As evidenced by a buried core of hydrophobic residues within globular proteins, hydropho... more ABSTRACT As evidenced by a buried core of hydrophobic residues within globular proteins, hydrophobicity provides essential insights into the folding structure of proteins. Previous studies have shown that hydrophobic residues show statistically meaningful distribution on the primary sequence, but most of them lacked further investigation into a potential relationship to secondary structure elements. In this paper we experimentally show that the hydrophobic residues collectively reveal different composition patterns over different secondary structure elements. After visually presenting the class-specific features, we quantitatively compare them using the statistical moments.
Biochimica Et Biophysica Acta-gene Structure and Expression, 2005
Genomic PCR reactions were performed to isolate gene sequences of tilapia metallothionein (tiMT) ... more Genomic PCR reactions were performed to isolate gene sequences of tilapia metallothionein (tiMT) from Oreochromis mossambicus and Oreochromis aureus. Two AP1 binding sites, four metal responsive elements, and a TATA box are the major cis-acting elements identified in the 800-bp 5' flanking region of the tiMTs obtained in this study. The tiMT gene promoter cloned from O. aureus was characterized in vitro using PLHC-1 cell-line, a hepatocellular carcinoma of a desert topminnow (Poecciliopsis lucida), following the administrations of Cd2+, Co2+, Cu2+, Ni2+, Pb2+ and Zn2+. Only Cd2+, Pb2+ and Zn2+ were able to induce the transcription of tiMT gene promoter in PLHC-1 cells in a dose-dependent manner. Zn2+ had the highest fold induction of tiMT gene promoter activity. Deletion mutants were tested for their abilities to drive the transcription of reporter gene following Cd2+ and Zn2+ administrations. However, Cu2+ and Ni2+ also induced the production of hepatic MT mRNA in vivo. Northern blot analysis showed that liver gave the highest fold induction of MT gene expression following the administration of heavy metal ions. These data indicated that hepatic MT mRNA level in tilapia is a potential sensitive biomarker of exposure to various metal ions including Cu2+, Cd2+, Ni2+, Pb2+, Hg2+ and Zn2+ ions.
IEEE Transactions on Consumer Electronics, 1994
... 7 R F Ferraro, Progmninier '.r (;iiide lo rhe IIGA arid I '(;A ('a... more ... 7 R F Ferraro, Progmninier '.r (;iiide lo rhe IIGA arid I '(;A ('ardy Addison-Wesley Publishing Company, 1988 8 R Wilton, Programmer's Guide to PC and PSI2 Yideo Systems, Miocrosofl Press, 1987 Biographies ... K T Lau is a senior lecturer in the School-of EEE, NTU, Singapore. ...
We study the design of cryptographic primitives resistant to a large class of side-channel attack... more We study the design of cryptographic primitives resistant to a large class of side-channel attacks, called “memory attacks”, where an attacker can repeatedly and adaptively learn information about the secret key, subject only to the constraint that the overall amount of such information is bounded by some parameter ℓ. Although the study of such primitives was initiated only recently by Akavia et al. [2], subsequent work already produced many such “leakage-resilient” primitives [48,4,42], including signature, encryption, identification (ID) and authenticated key agreement (AKA) schemes. Unfortunately, every existing scheme, — for any of the four fundamental primitives above, — fails to satisfy at least one of the following desirable properties: Efficiency. While the construction may be generic, it should have some efficient instantiations, based on standard cryptographic assumptions, and without relying on random oracles. Strong Security. The construction should satisfy the strongest possible definition of security (even in the presence of leakage). For example, encryption schemes should be secure against chosen ciphertext attack (CCA), while signatures should be existentially unforgeable. Leakage Flexibility. It should be possible to set the scheme parameters so that the leakage bound ℓ can come arbitrarily close to the secret-key size. In this work we design the first signature, encryption, ID and AKA schemes which overcome these limitations, and satisfy all the properties above. Moreover, all our constructions are generic, in several cases elegantly simplifying and generalizing the prior constructions (which did not have any efficient instantiations). We also introduce several tools of independent interest, such as the abstraction (and constructions) of true-simulation extractable NIZK arguments, and a new deniable DH-based AKA protocol based on any CCA-secure encryption.
This research develops an empirical model to explore the factors that influence consumers' behavi... more This research develops an empirical model to explore the factors that influence consumers' behaviour while using a mobile phone as a converged device, i.e., using different functions and services on a mobile phone for multiple purposes. Convergence in this domain is particularly regarded as a social phenomenon that has now existed for over two decades. However, empirical research is lacking in terms of individual's perception and behaviour toward using a converged device. This research is the first to provide an exploratory study of individual uses of a mobile phone for personal information management (PIM), e-mail, entertainment, and commercial transaction. It also draws from the Technology Acceptance Model (TAM) and identifies some of the antecedent factors that influence the above behaviours and behavioural intentions.
ABSTRACT As evidenced by a buried core of hydrophobic residues within globular proteins, hydropho... more ABSTRACT As evidenced by a buried core of hydrophobic residues within globular proteins, hydrophobicity provides essential insights into the folding structure of proteins. Previous studies have shown that hydrophobic residues show statistically meaningful distribution on the primary sequence, but most of them lacked further investigation into a potential relationship to secondary structure elements. In this paper we experimentally show that the hydrophobic residues collectively reveal different composition patterns over different secondary structure elements. After visually presenting the class-specific features, we quantitatively compare them using the statistical moments.
Biochimica Et Biophysica Acta-gene Structure and Expression, 2005
Genomic PCR reactions were performed to isolate gene sequences of tilapia metallothionein (tiMT) ... more Genomic PCR reactions were performed to isolate gene sequences of tilapia metallothionein (tiMT) from Oreochromis mossambicus and Oreochromis aureus. Two AP1 binding sites, four metal responsive elements, and a TATA box are the major cis-acting elements identified in the 800-bp 5' flanking region of the tiMTs obtained in this study. The tiMT gene promoter cloned from O. aureus was characterized in vitro using PLHC-1 cell-line, a hepatocellular carcinoma of a desert topminnow (Poecciliopsis lucida), following the administrations of Cd2+, Co2+, Cu2+, Ni2+, Pb2+ and Zn2+. Only Cd2+, Pb2+ and Zn2+ were able to induce the transcription of tiMT gene promoter in PLHC-1 cells in a dose-dependent manner. Zn2+ had the highest fold induction of tiMT gene promoter activity. Deletion mutants were tested for their abilities to drive the transcription of reporter gene following Cd2+ and Zn2+ administrations. However, Cu2+ and Ni2+ also induced the production of hepatic MT mRNA in vivo. Northern blot analysis showed that liver gave the highest fold induction of MT gene expression following the administration of heavy metal ions. These data indicated that hepatic MT mRNA level in tilapia is a potential sensitive biomarker of exposure to various metal ions including Cu2+, Cd2+, Ni2+, Pb2+, Hg2+ and Zn2+ ions.
IEEE Transactions on Consumer Electronics, 1994
... 7 R F Ferraro, Progmninier '.r (;iiide lo rhe IIGA arid I '(;A ('a... more ... 7 R F Ferraro, Progmninier '.r (;iiide lo rhe IIGA arid I '(;A ('ardy Addison-Wesley Publishing Company, 1988 8 R Wilton, Programmer's Guide to PC and PSI2 Yideo Systems, Miocrosofl Press, 1987 Biographies ... K T Lau is a senior lecturer in the School-of EEE, NTU, Singapore. ...
We study the design of cryptographic primitives resistant to a large class of side-channel attack... more We study the design of cryptographic primitives resistant to a large class of side-channel attacks, called “memory attacks”, where an attacker can repeatedly and adaptively learn information about the secret key, subject only to the constraint that the overall amount of such information is bounded by some parameter ℓ. Although the study of such primitives was initiated only recently by Akavia et al. [2], subsequent work already produced many such “leakage-resilient” primitives [48,4,42], including signature, encryption, identification (ID) and authenticated key agreement (AKA) schemes. Unfortunately, every existing scheme, — for any of the four fundamental primitives above, — fails to satisfy at least one of the following desirable properties: Efficiency. While the construction may be generic, it should have some efficient instantiations, based on standard cryptographic assumptions, and without relying on random oracles. Strong Security. The construction should satisfy the strongest possible definition of security (even in the presence of leakage). For example, encryption schemes should be secure against chosen ciphertext attack (CCA), while signatures should be existentially unforgeable. Leakage Flexibility. It should be possible to set the scheme parameters so that the leakage bound ℓ can come arbitrarily close to the secret-key size. In this work we design the first signature, encryption, ID and AKA schemes which overcome these limitations, and satisfy all the properties above. Moreover, all our constructions are generic, in several cases elegantly simplifying and generalizing the prior constructions (which did not have any efficient instantiations). We also introduce several tools of independent interest, such as the abstraction (and constructions) of true-simulation extractable NIZK arguments, and a new deniable DH-based AKA protocol based on any CCA-secure encryption.
This research develops an empirical model to explore the factors that influence consumers' behavi... more This research develops an empirical model to explore the factors that influence consumers' behaviour while using a mobile phone as a converged device, i.e., using different functions and services on a mobile phone for multiple purposes. Convergence in this domain is particularly regarded as a social phenomenon that has now existed for over two decades. However, empirical research is lacking in terms of individual's perception and behaviour toward using a converged device. This research is the first to provide an exploratory study of individual uses of a mobile phone for personal information management (PIM), e-mail, entertainment, and commercial transaction. It also draws from the Technology Acceptance Model (TAM) and identifies some of the antecedent factors that influence the above behaviours and behavioural intentions.