In the past ten years, the increasing customer awareness of environmental sustainability has driv... more In the past ten years, the increasing customer awareness of environmental sustainability has driven the development of green products. As the initiator of product development, this situation can challenge product designers. Since customers may have varied expectations and preferences for green products, it depends on the green attributes embedded in the product and cultural value influences. As the natural behavior setting, cultural value has been proven to influence customer preferences in the literature. However, it was identified that previous studies had not clearly defined the consideration of cultural values in green product design. Therefore, this study aimed to generate a conceptual framework for embedding cultural value consideration in green product design. A comprehensive review of green product design and cultural values has been performed to align the relevancies for constructing the conceptual framework. Bibliographic analysis using the PRISMA approach was also perform...
Improvement of the Convergence of the Development of Perturbative Function in the Case of the Space Circular Restrictive Problem of Three Bodies
We try to develop in this paper the perturbative function of the space circular restrictive probl... more We try to develop in this paper the perturbative function of the space circular restrictive problem of three bodies by means of linear transformation as defined by M. F. Soubbotin. Our method is different from that of Mr. Yih; we have used Prof. Soubbotin's theory as well as Prof. Elenevskaya's theorem. The results are given in the formulae (39), (51) and (53). The final result can be written in the following form: R_1=m' ∑ D e~m cos [AS+BI+C], the argument S being Soubbotin's variable, I the inclination of the orbit of the disturbing body to that of the disturbed, C a linear combination of п and п', A and B two constants, the coefficient D, function of α=a/a', contains mainly the products of the function B_n~s with F (p, υ, β) given by Prof. Soubbotin and Mr. Yih respectively.
The increasing customer awareness of environmental sustainability during the last decade has had ... more The increasing customer awareness of environmental sustainability during the last decade has had an influence on many manufacturers to produce green products. However, issues arise regarding the actual preferences of customers for green products, which often differ depending on cultural influences. Cultural values can affect the decisions of designers to determine detailed design specifications that relate to customer preferences. Currently, few guidelines consider cultural values as an aspect of green product design. Thus, the aim of this study is to develop a guideline that incorporates the influence of cultural values on green product design. Malaysia was selected as the location of this study. The sources of data to establish a guideline were obtained from customer perspectives on green products. Structural equation modeling (SEM) was used to identify cultural influences and preferences on green product characteristics as the input strategies for the proposed guideline. Professi...
Green product preferences considering cultural influences: a comparison study between Malaysia and Indonesia
Management of Environmental Quality: An International Journal, 2021
PurposeThere is an increasing awareness among manufacturers to make production more sustainable i... more PurposeThere is an increasing awareness among manufacturers to make production more sustainable in Southeast Asian countries such as Malaysia and Indonesia. Manufacturers are now urged to not only focus on the business profit but also concern on environment protection by producing green products. However, issues may arise regarding the preferences of customers on green products, which will vary due to the influence of cultural values. This will give an impact on the marketing of green products. The aim of this study is to identify the influence of cultural values on the green products design in Malaysia and Indonesia.Design/methodology/approachA pretest on the survey instruments was performed to ensure the reliability and validity of the questionnaire. The collected data were statistically analyzed based on the satisfaction level, confirmatory factor analysis and structural equation modeling.FindingsThe results showed that customer preferences in Malaysia were mostly influenced by u...
A circular economy can be achieved by the efficient use of materials across different industries ... more A circular economy can be achieved by the efficient use of materials across different industries and sectors. In the manufacturing sectors, practicing material efficiency is one of the effective strategies to reduce material usage and solid waste generation. However, due to many unknown factors, such as key drivers to enhance material efficiency, most of the time, manufacturers are practicing at the minimum level of material saving. This study aims to examine the key drivers of material efficiency among electrical and electronic (E&E) companies to fulfill the aims of sustainable manufacturing. The data collection and synthesis were conducted using semi-structured interviews and an analytical hierarchy process survey. In this study, thirteen key drivers were found. Five internal drivers and eight external drivers with different priorities were found to influence E&E companies in the practice of material efficiency strategies. In addition, the drivers’ implications to different practi...
IOP Conference Series: Materials Science and Engineering, 2019
In powder coating industry, product over-cured and poor surface finishing are both utmost issues ... more In powder coating industry, product over-cured and poor surface finishing are both utmost issues faced by the manufacturer. One of the reasons is due to the poor synchronization between powder coating conveyor speed, number of operators in loading and unloading bay, and variety of products to be powder coated. This study is conducted in a metal industry company located at Johor with powder coating facility. Raw data were collected through documentation and observation such as complete operation activities of the powder coating process, the actual layout of the powder coating workstation. The raw data were then converted into simulation scenario using Arena software to determine the configuration between conveyor speed, number of operator, and consideration of three variants of product (small, medium, big) in order to achieve best synchronization. Next, the obtained findings were validated with the actual industry data. A balanced synchronized matrix is developed in the end of this s...
The circular economy (CE) is in a growing trend, especially to address the concern of resources s... more The circular economy (CE) is in a growing trend, especially to address the concern of resources sustainability, both from academics as well as industrial practitioners. For manufacturing businesses and services to be sustainable, using materials efficiently is an essential strategy, which is able to enhance the promotion of CE. However, for a developing country like Malaysia, little is known about the ongoing material efficiency strategies among the manufacturers. This paper presents a qualitative investigation of adopting material efficiency strategies in the manufacturing industry. Semi-structured interviews were used to explore the material efficiency strategies at selected Electrical and Electronics (E&E) companies in Malaysia. A list of 11 E&E companies material efficiency strategies were determined and explicated. This paper provides valuable insights to academics and practitioners for a better understanding of the current practices pertaining to the material efficiency strate...
KPT Power Photos n today's freeway traffic there is very little control that can effectively infl... more KPT Power Photos n today's freeway traffic there is very little control that can effectively influence the flow of traffic and manage congestion. Apart from ramp metering, the flow of traffic is mainly influenced by the actions of individual drivers. These actions are very erratic. They differ from one place to another and are responsible for traffic flow instabilities that lead to congestion and inefficient use of highways. In this article we use an artificial neural network technique to model and control highway traffic in a single lane with no onor off-ramps. The developed controllers generate the speed commands for each section of the lane that vehicles need to follow in order to achieve a desired traffic flow density distribution along the lane. In today's traffic, these speed commands could be communicated to drivers, who would then have to respond to
Material efficiency is one of the most important strategies for helping manufacturing companies a... more Material efficiency is one of the most important strategies for helping manufacturing companies achieve sustainability in their production activities. However, there are many barriers to the implementation of material efficiency strategies in the manufacturing processes and overall business operations. The aim of this study is to identify and evaluate the barriers faced by Electrical and Electronics (E&E) manufacturing companies in Malaysia in implementing material efficiency strategies. A mixed-mode research method was employed to collect data from these companies. Semi-structured interviews were used to identify the barriers faced by the Malaysian Electrical and Electronics (E&E) industry, while an Analytic Hierarchy Process (AHP) survey was utilized to determine the importance of each barrier. Seven companies participated in the semi-structured interviews, and 18 companies took part in the AHP survey. Nine barriers were generated from analysis of the interviews, and were then ranked by priority using the AHP method. These important findings could be used as a guide for E&E companies in managing or overcoming barriers during the implementation of material efficiency strategies and other sustainable manufacturing activities.
Cells are known to respond to multiple niche signals including extracellular matrix and mechanica... more Cells are known to respond to multiple niche signals including extracellular matrix and mechanical loading. In others and our own studies, mechanical loading has been shown to induce the formation of cell alignment in 3D collagen matrix with random meshwork, challenging our traditional understanding on the necessity of having aligned substrates as the prerequisite of alignment formation. This motivates our adventure in deciphering the mechanism of loading-induced cell alignment and hence the discovery of the novel protrusive functional structure at the cell-matrix interface. Here we report the formation of mechanoresponsive, omni-directional and local matrix-degrading actin protrusions in human mesenchymal stem cells (hMSCs) microencapsulated in collagen following a shifted actin assembly/disassembly balance. These actin protrusive structures exhibit morphological and compositional similarity to filopodia and invadopodia but differ from them in stability, abundance, signaling and fu...
In Automated Highway Systems (AHS), vehicles will be able to follow each other automatically by u... more In Automated Highway Systems (AHS), vehicles will be able to follow each other automatically by using their own sensing and control systems, effectively reducing the role of the human driver in the operation of the vehicle. Such systems are therefore capable of reducing one source of error, human error, that diminishes the potential capacity of the highways and in the worst case becomes the cause of accidents. The inter-vehicle separation during vehicle following is one of the most critical parameters of the AHS system, as it affects both safety and highway capacity. To achieve the goal of improved highway capacity, the inter-vehicle separation should be as small as possible. On the other hand, to achieve the goal of improved safety and elimination of rear end collisions, the inter-vehicle separation should be large enough that even under a worst case stopping scenario, no vehicle collisions will take place. These two requirements demand diametrically opposing solutions and they have to be traded off. Since safety cannot be compromised for the sake of capacity, it becomes a serious constraint in most AHS design decisions. The trade-off between capacity and safety gives rise to a variety of different AHS concepts and architectures. In this study we consider a family of six AHS operational concepts. For each concept we calculate the minimum inter-vehicle spacing that could be used for collision-free vehicle following, under different road conditions. For architectures involving platoons we also use the alternative constraint of bounded energy collisions to calculate the spacing that can be applied if we allowed collisions at a limited relative velocity. In every case, the minimum spacing in turn, is used to calculate the maximum possible capacity that could be achieved for each operational concept.
The stem cell niche, or microenvironment, consists of soluble, matrix, cell and mechanical factor... more The stem cell niche, or microenvironment, consists of soluble, matrix, cell and mechanical factors that together determine the cellular fates and/or differentiation patterns of stem cells. Collagen and glycosaminoglycans (GAGs) are important scaffolding materials that can mimic the natural matrix niche. Here, we hypothesize that imposing changes in the scaffold composition or, more specifically, incorporating GAGs into the collagen meshwork, will affect the morphology, cytoskeletal organization and integrin expression profiles, and hence the fate of human mesenchymal stem cells (MSCs) upon the induction of differentiation. Using chondrogenesis as an example, we microencapsulated MSCs in three scaffold systems that had varying matrix compositions: collagen alone (C), aminated collagen (AC) and aminated collagen with GAGs (ACG). We then induced the MSCs to differentiate toward a chondrogenic lineage, after which, we characterized the cell viability and morphology, as well as the level...
Fabrication and optical studies of monolayer assemblies of Au nanoparticles
Scanning
Two-dimensional nanoparticle self-assemblies provide a means of tuning the optical properties by ... more Two-dimensional nanoparticle self-assemblies provide a means of tuning the optical properties by manipulation of the fabrication parameters, thereby controlling the light-matter interaction. We report fabrication of self-assembled monolayers of colloidal gold nanoparticles on organosilane-coated substrates and a study of the linear and nonlinear optical properties. With increase in particle coverage of the gold monolayer self assemblies, an additional band in the absorption spectrum due to the collective particle surface plasmon resonance could be seen. The intensity and lambda(max) of this feature depends on the interparticle spacing and particle aggregation. Z-scan measurements show a saturable absorption behavior and a negative nonlinear refractive index of the monolayer films. A strong correlation between particle density and the linear and nonlinear optical properties is established.
Biomimetic materials are used for creating microsystems to control cell growth spatially and elic... more Biomimetic materials are used for creating microsystems to control cell growth spatially and elicit specific cellular responses by combining complex biomolecules with nanostructured surfaces. Intercellular cell-to-cell and cell-to-extracellular matrix (ECM) interactions in biomimetic materials have demonstrated potential in the development of drug discovery platforms and regeneration medicine. In this study, we developed a biomimetic nanostructured matrix by using various ECM molecular layers to create a biomimetic and biocompatible environment for realizing neuronal guidance in neural regeneration medicine. Silicon-based substrates possessing nanostructures were modified using different ECM proteins and peptides to develop a biomimetic and biocompatible environment for studying neural behaviors in adhesion, proliferation, and differentiation. The substrates were flat glass, flat silicon wafers (FWs), and nanorod-structured wafers prepared using wet etching. The three substrates were then functionalized using laminin-1 peptide, PA22-2-contained active isoleucine-lysine-valine-alanine-valine (IKVAV) peptide, and poly-d-lysine (PDL), separately. When PC12 cells were cultured and differentiated on the modified substrates, the cells were able to elongate the neurites on the glass and FW, which was coated with three types of peptide. More differentiated neurons were observed on the nanorod-structured wafers coated with laminin than on those coated with IKVAV or PDL. For achieving directional guidance of neurite outgrowth, substrates exhibiting a grating pattern of nanorods were partially collapsed by the pulling force of water, leaving few nanorods, which support the net form of laminin on the surface. Furthermore, we fabricated the topological nanostructure-patterned wafer coated with laminin and successfully manipulated the extension and direction of neurites by using more than 80 m of a single soma. This approach demonstrates potential as a facile and efficient method for guiding the direction of single axons and for enhancing neurite outgrowth in studies on nerve regenerative medicine.
The advantage of the ID-based authentication protocols over public-key based protocols is that au... more The advantage of the ID-based authentication protocols over public-key based protocols is that authentication can be performed by simply knowing the identity of a party. Meanwhile, Public Key Infrastructure (PKI) provides a suite of excellent security and user management mechanisms that can be easily deployed to the Internet. In this paper, we present an ID-based proxy authentication protocol that can be interoperable with PKI. The proposed protocol leverages the management mechanisms of PKI while inheriting the nature of traditional ID-based protocols. In our protocol, a proxy certificate authority (PCA) is proposed to act as a bridge between an ID-based domain and the PKI domain. Authentication between two entities of different domains is thus made possible with the help of the proxy CA. The proposed protocol minimizes the message exchange overhead within an ID-based domain and supports both initial and subsequent authentication. In addition, a security analysis is presented to ve...
In this paper, a new Global System of Mobile Communications (GSM) authentication protocol is prop... more In this paper, a new Global System of Mobile Communications (GSM) authentication protocol is proposed to improve some drawbacks of the current GSM authentication protocol for roaming users including: (a) communication overhead between VLR; (b) huge bandwidth consumption between VLR and HLR; (c) storage space overhead in VLR; (d) overloaded in HLR with authentication of mobile stations; and (e) not supporting bilateral authentication. The main contribution of this paper is that it does not only improve the drawbacks listed above but also fits the needs of roaming users. In addition, the proposed protocol does not change the existing architecture of GSM, and the robustness of the proposed protocol is the same as that of the original GSM, which is based on security algorithms A3, A5, and A8.
Review of Quantitative Finance and Accounting, 2010
The main purpose of this paper to examine how the reputation effect of venture capital (VC) is as... more The main purpose of this paper to examine how the reputation effect of venture capital (VC) is associated with the initial return and ex-post performance of its invested IPO firms. In this paper, we use 267 Taiwanese IPO firms in 1994–2007 periods and find that VC-backed firms outperform non-VC-backed firms in terms of ex-post equity market-to-book ratio, ROA and R&D expenditure ratio. For those VC-backed IPOs, reputable VC-backed firms outperform mediocre VC-backed ones. Moreover, among the four proxies of VC reputation, the market share with respect to total IPO proceeds is most promising in explaining IPO firms’ ex-post performance. The overall result confirms the reputation effect associated with VC.
Review of Pacific Basin Financial Markets and Policies, 2012
The main purpose of this paper is to investigate how investors perceive and respond to a firm'... more The main purpose of this paper is to investigate how investors perceive and respond to a firm's R&D announcement. We propose that board structure and intra-industry competition jointly dictate the announcement return. In addition, we assume that investors prefer carefully scrutinized R&D investments to mitigate asymmetric-information risks. Finally, we assume that investors prefer a sustainable R&D investment to prevent intense intra-industry competition and to ensure profit potential. We use a sample of 229 announcements made by 116 Taiwanese listed firms to verify our postulation. Our postulation is the abnormal returns are positively correlated with board independence while negatively correlated with board size. We construct two variables to capture intra-industry competition: (i) the number of days that have elapsed since a competitor's prior announcement and (ii) the ordinal number of announcements in the same industry. Our results show that the announcement effect is n...
In the past ten years, the increasing customer awareness of environmental sustainability has driv... more In the past ten years, the increasing customer awareness of environmental sustainability has driven the development of green products. As the initiator of product development, this situation can challenge product designers. Since customers may have varied expectations and preferences for green products, it depends on the green attributes embedded in the product and cultural value influences. As the natural behavior setting, cultural value has been proven to influence customer preferences in the literature. However, it was identified that previous studies had not clearly defined the consideration of cultural values in green product design. Therefore, this study aimed to generate a conceptual framework for embedding cultural value consideration in green product design. A comprehensive review of green product design and cultural values has been performed to align the relevancies for constructing the conceptual framework. Bibliographic analysis using the PRISMA approach was also perform...
Improvement of the Convergence of the Development of Perturbative Function in the Case of the Space Circular Restrictive Problem of Three Bodies
We try to develop in this paper the perturbative function of the space circular restrictive probl... more We try to develop in this paper the perturbative function of the space circular restrictive problem of three bodies by means of linear transformation as defined by M. F. Soubbotin. Our method is different from that of Mr. Yih; we have used Prof. Soubbotin's theory as well as Prof. Elenevskaya's theorem. The results are given in the formulae (39), (51) and (53). The final result can be written in the following form: R_1=m' ∑ D e~m cos [AS+BI+C], the argument S being Soubbotin's variable, I the inclination of the orbit of the disturbing body to that of the disturbed, C a linear combination of п and п', A and B two constants, the coefficient D, function of α=a/a', contains mainly the products of the function B_n~s with F (p, υ, β) given by Prof. Soubbotin and Mr. Yih respectively.
The increasing customer awareness of environmental sustainability during the last decade has had ... more The increasing customer awareness of environmental sustainability during the last decade has had an influence on many manufacturers to produce green products. However, issues arise regarding the actual preferences of customers for green products, which often differ depending on cultural influences. Cultural values can affect the decisions of designers to determine detailed design specifications that relate to customer preferences. Currently, few guidelines consider cultural values as an aspect of green product design. Thus, the aim of this study is to develop a guideline that incorporates the influence of cultural values on green product design. Malaysia was selected as the location of this study. The sources of data to establish a guideline were obtained from customer perspectives on green products. Structural equation modeling (SEM) was used to identify cultural influences and preferences on green product characteristics as the input strategies for the proposed guideline. Professi...
Green product preferences considering cultural influences: a comparison study between Malaysia and Indonesia
Management of Environmental Quality: An International Journal, 2021
PurposeThere is an increasing awareness among manufacturers to make production more sustainable i... more PurposeThere is an increasing awareness among manufacturers to make production more sustainable in Southeast Asian countries such as Malaysia and Indonesia. Manufacturers are now urged to not only focus on the business profit but also concern on environment protection by producing green products. However, issues may arise regarding the preferences of customers on green products, which will vary due to the influence of cultural values. This will give an impact on the marketing of green products. The aim of this study is to identify the influence of cultural values on the green products design in Malaysia and Indonesia.Design/methodology/approachA pretest on the survey instruments was performed to ensure the reliability and validity of the questionnaire. The collected data were statistically analyzed based on the satisfaction level, confirmatory factor analysis and structural equation modeling.FindingsThe results showed that customer preferences in Malaysia were mostly influenced by u...
A circular economy can be achieved by the efficient use of materials across different industries ... more A circular economy can be achieved by the efficient use of materials across different industries and sectors. In the manufacturing sectors, practicing material efficiency is one of the effective strategies to reduce material usage and solid waste generation. However, due to many unknown factors, such as key drivers to enhance material efficiency, most of the time, manufacturers are practicing at the minimum level of material saving. This study aims to examine the key drivers of material efficiency among electrical and electronic (E&E) companies to fulfill the aims of sustainable manufacturing. The data collection and synthesis were conducted using semi-structured interviews and an analytical hierarchy process survey. In this study, thirteen key drivers were found. Five internal drivers and eight external drivers with different priorities were found to influence E&E companies in the practice of material efficiency strategies. In addition, the drivers’ implications to different practi...
IOP Conference Series: Materials Science and Engineering, 2019
In powder coating industry, product over-cured and poor surface finishing are both utmost issues ... more In powder coating industry, product over-cured and poor surface finishing are both utmost issues faced by the manufacturer. One of the reasons is due to the poor synchronization between powder coating conveyor speed, number of operators in loading and unloading bay, and variety of products to be powder coated. This study is conducted in a metal industry company located at Johor with powder coating facility. Raw data were collected through documentation and observation such as complete operation activities of the powder coating process, the actual layout of the powder coating workstation. The raw data were then converted into simulation scenario using Arena software to determine the configuration between conveyor speed, number of operator, and consideration of three variants of product (small, medium, big) in order to achieve best synchronization. Next, the obtained findings were validated with the actual industry data. A balanced synchronized matrix is developed in the end of this s...
The circular economy (CE) is in a growing trend, especially to address the concern of resources s... more The circular economy (CE) is in a growing trend, especially to address the concern of resources sustainability, both from academics as well as industrial practitioners. For manufacturing businesses and services to be sustainable, using materials efficiently is an essential strategy, which is able to enhance the promotion of CE. However, for a developing country like Malaysia, little is known about the ongoing material efficiency strategies among the manufacturers. This paper presents a qualitative investigation of adopting material efficiency strategies in the manufacturing industry. Semi-structured interviews were used to explore the material efficiency strategies at selected Electrical and Electronics (E&E) companies in Malaysia. A list of 11 E&E companies material efficiency strategies were determined and explicated. This paper provides valuable insights to academics and practitioners for a better understanding of the current practices pertaining to the material efficiency strate...
KPT Power Photos n today's freeway traffic there is very little control that can effectively infl... more KPT Power Photos n today's freeway traffic there is very little control that can effectively influence the flow of traffic and manage congestion. Apart from ramp metering, the flow of traffic is mainly influenced by the actions of individual drivers. These actions are very erratic. They differ from one place to another and are responsible for traffic flow instabilities that lead to congestion and inefficient use of highways. In this article we use an artificial neural network technique to model and control highway traffic in a single lane with no onor off-ramps. The developed controllers generate the speed commands for each section of the lane that vehicles need to follow in order to achieve a desired traffic flow density distribution along the lane. In today's traffic, these speed commands could be communicated to drivers, who would then have to respond to
Material efficiency is one of the most important strategies for helping manufacturing companies a... more Material efficiency is one of the most important strategies for helping manufacturing companies achieve sustainability in their production activities. However, there are many barriers to the implementation of material efficiency strategies in the manufacturing processes and overall business operations. The aim of this study is to identify and evaluate the barriers faced by Electrical and Electronics (E&E) manufacturing companies in Malaysia in implementing material efficiency strategies. A mixed-mode research method was employed to collect data from these companies. Semi-structured interviews were used to identify the barriers faced by the Malaysian Electrical and Electronics (E&E) industry, while an Analytic Hierarchy Process (AHP) survey was utilized to determine the importance of each barrier. Seven companies participated in the semi-structured interviews, and 18 companies took part in the AHP survey. Nine barriers were generated from analysis of the interviews, and were then ranked by priority using the AHP method. These important findings could be used as a guide for E&E companies in managing or overcoming barriers during the implementation of material efficiency strategies and other sustainable manufacturing activities.
Cells are known to respond to multiple niche signals including extracellular matrix and mechanica... more Cells are known to respond to multiple niche signals including extracellular matrix and mechanical loading. In others and our own studies, mechanical loading has been shown to induce the formation of cell alignment in 3D collagen matrix with random meshwork, challenging our traditional understanding on the necessity of having aligned substrates as the prerequisite of alignment formation. This motivates our adventure in deciphering the mechanism of loading-induced cell alignment and hence the discovery of the novel protrusive functional structure at the cell-matrix interface. Here we report the formation of mechanoresponsive, omni-directional and local matrix-degrading actin protrusions in human mesenchymal stem cells (hMSCs) microencapsulated in collagen following a shifted actin assembly/disassembly balance. These actin protrusive structures exhibit morphological and compositional similarity to filopodia and invadopodia but differ from them in stability, abundance, signaling and fu...
In Automated Highway Systems (AHS), vehicles will be able to follow each other automatically by u... more In Automated Highway Systems (AHS), vehicles will be able to follow each other automatically by using their own sensing and control systems, effectively reducing the role of the human driver in the operation of the vehicle. Such systems are therefore capable of reducing one source of error, human error, that diminishes the potential capacity of the highways and in the worst case becomes the cause of accidents. The inter-vehicle separation during vehicle following is one of the most critical parameters of the AHS system, as it affects both safety and highway capacity. To achieve the goal of improved highway capacity, the inter-vehicle separation should be as small as possible. On the other hand, to achieve the goal of improved safety and elimination of rear end collisions, the inter-vehicle separation should be large enough that even under a worst case stopping scenario, no vehicle collisions will take place. These two requirements demand diametrically opposing solutions and they have to be traded off. Since safety cannot be compromised for the sake of capacity, it becomes a serious constraint in most AHS design decisions. The trade-off between capacity and safety gives rise to a variety of different AHS concepts and architectures. In this study we consider a family of six AHS operational concepts. For each concept we calculate the minimum inter-vehicle spacing that could be used for collision-free vehicle following, under different road conditions. For architectures involving platoons we also use the alternative constraint of bounded energy collisions to calculate the spacing that can be applied if we allowed collisions at a limited relative velocity. In every case, the minimum spacing in turn, is used to calculate the maximum possible capacity that could be achieved for each operational concept.
The stem cell niche, or microenvironment, consists of soluble, matrix, cell and mechanical factor... more The stem cell niche, or microenvironment, consists of soluble, matrix, cell and mechanical factors that together determine the cellular fates and/or differentiation patterns of stem cells. Collagen and glycosaminoglycans (GAGs) are important scaffolding materials that can mimic the natural matrix niche. Here, we hypothesize that imposing changes in the scaffold composition or, more specifically, incorporating GAGs into the collagen meshwork, will affect the morphology, cytoskeletal organization and integrin expression profiles, and hence the fate of human mesenchymal stem cells (MSCs) upon the induction of differentiation. Using chondrogenesis as an example, we microencapsulated MSCs in three scaffold systems that had varying matrix compositions: collagen alone (C), aminated collagen (AC) and aminated collagen with GAGs (ACG). We then induced the MSCs to differentiate toward a chondrogenic lineage, after which, we characterized the cell viability and morphology, as well as the level...
Fabrication and optical studies of monolayer assemblies of Au nanoparticles
Scanning
Two-dimensional nanoparticle self-assemblies provide a means of tuning the optical properties by ... more Two-dimensional nanoparticle self-assemblies provide a means of tuning the optical properties by manipulation of the fabrication parameters, thereby controlling the light-matter interaction. We report fabrication of self-assembled monolayers of colloidal gold nanoparticles on organosilane-coated substrates and a study of the linear and nonlinear optical properties. With increase in particle coverage of the gold monolayer self assemblies, an additional band in the absorption spectrum due to the collective particle surface plasmon resonance could be seen. The intensity and lambda(max) of this feature depends on the interparticle spacing and particle aggregation. Z-scan measurements show a saturable absorption behavior and a negative nonlinear refractive index of the monolayer films. A strong correlation between particle density and the linear and nonlinear optical properties is established.
Biomimetic materials are used for creating microsystems to control cell growth spatially and elic... more Biomimetic materials are used for creating microsystems to control cell growth spatially and elicit specific cellular responses by combining complex biomolecules with nanostructured surfaces. Intercellular cell-to-cell and cell-to-extracellular matrix (ECM) interactions in biomimetic materials have demonstrated potential in the development of drug discovery platforms and regeneration medicine. In this study, we developed a biomimetic nanostructured matrix by using various ECM molecular layers to create a biomimetic and biocompatible environment for realizing neuronal guidance in neural regeneration medicine. Silicon-based substrates possessing nanostructures were modified using different ECM proteins and peptides to develop a biomimetic and biocompatible environment for studying neural behaviors in adhesion, proliferation, and differentiation. The substrates were flat glass, flat silicon wafers (FWs), and nanorod-structured wafers prepared using wet etching. The three substrates were then functionalized using laminin-1 peptide, PA22-2-contained active isoleucine-lysine-valine-alanine-valine (IKVAV) peptide, and poly-d-lysine (PDL), separately. When PC12 cells were cultured and differentiated on the modified substrates, the cells were able to elongate the neurites on the glass and FW, which was coated with three types of peptide. More differentiated neurons were observed on the nanorod-structured wafers coated with laminin than on those coated with IKVAV or PDL. For achieving directional guidance of neurite outgrowth, substrates exhibiting a grating pattern of nanorods were partially collapsed by the pulling force of water, leaving few nanorods, which support the net form of laminin on the surface. Furthermore, we fabricated the topological nanostructure-patterned wafer coated with laminin and successfully manipulated the extension and direction of neurites by using more than 80 m of a single soma. This approach demonstrates potential as a facile and efficient method for guiding the direction of single axons and for enhancing neurite outgrowth in studies on nerve regenerative medicine.
The advantage of the ID-based authentication protocols over public-key based protocols is that au... more The advantage of the ID-based authentication protocols over public-key based protocols is that authentication can be performed by simply knowing the identity of a party. Meanwhile, Public Key Infrastructure (PKI) provides a suite of excellent security and user management mechanisms that can be easily deployed to the Internet. In this paper, we present an ID-based proxy authentication protocol that can be interoperable with PKI. The proposed protocol leverages the management mechanisms of PKI while inheriting the nature of traditional ID-based protocols. In our protocol, a proxy certificate authority (PCA) is proposed to act as a bridge between an ID-based domain and the PKI domain. Authentication between two entities of different domains is thus made possible with the help of the proxy CA. The proposed protocol minimizes the message exchange overhead within an ID-based domain and supports both initial and subsequent authentication. In addition, a security analysis is presented to ve...
In this paper, a new Global System of Mobile Communications (GSM) authentication protocol is prop... more In this paper, a new Global System of Mobile Communications (GSM) authentication protocol is proposed to improve some drawbacks of the current GSM authentication protocol for roaming users including: (a) communication overhead between VLR; (b) huge bandwidth consumption between VLR and HLR; (c) storage space overhead in VLR; (d) overloaded in HLR with authentication of mobile stations; and (e) not supporting bilateral authentication. The main contribution of this paper is that it does not only improve the drawbacks listed above but also fits the needs of roaming users. In addition, the proposed protocol does not change the existing architecture of GSM, and the robustness of the proposed protocol is the same as that of the original GSM, which is based on security algorithms A3, A5, and A8.
Review of Quantitative Finance and Accounting, 2010
The main purpose of this paper to examine how the reputation effect of venture capital (VC) is as... more The main purpose of this paper to examine how the reputation effect of venture capital (VC) is associated with the initial return and ex-post performance of its invested IPO firms. In this paper, we use 267 Taiwanese IPO firms in 1994–2007 periods and find that VC-backed firms outperform non-VC-backed firms in terms of ex-post equity market-to-book ratio, ROA and R&D expenditure ratio. For those VC-backed IPOs, reputable VC-backed firms outperform mediocre VC-backed ones. Moreover, among the four proxies of VC reputation, the market share with respect to total IPO proceeds is most promising in explaining IPO firms’ ex-post performance. The overall result confirms the reputation effect associated with VC.
Review of Pacific Basin Financial Markets and Policies, 2012
The main purpose of this paper is to investigate how investors perceive and respond to a firm'... more The main purpose of this paper is to investigate how investors perceive and respond to a firm's R&D announcement. We propose that board structure and intra-industry competition jointly dictate the announcement return. In addition, we assume that investors prefer carefully scrutinized R&D investments to mitigate asymmetric-information risks. Finally, we assume that investors prefer a sustainable R&D investment to prevent intense intra-industry competition and to ensure profit potential. We use a sample of 229 announcements made by 116 Taiwanese listed firms to verify our postulation. Our postulation is the abnormal returns are positively correlated with board independence while negatively correlated with board size. We construct two variables to capture intra-industry competition: (i) the number of days that have elapsed since a competitor's prior announcement and (ii) the ordinal number of announcements in the same industry. Our results show that the announcement effect is n...
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Papers by Tsz fu Ho