Chia-Hsiang Chang - Academia.edu (original) (raw)

Papers by Chia-Hsiang Chang

We show how to turn a regular expression into an O(s) space representation of McNaughton and Yama... more We show how to turn a regular expression into an O(s) space representation of McNaughton and Yamada's NFA, where s is the number of NFA states. The standard adjacency list representation of McNaughton and Yamada's NFA takes up s+s 2 space in the worst case. The adjacency list representation of the NFA produced by Thompson takes up between 2r and 5r space, where r s in general, and can be arbitrarily larger than s. Given any set T of NFA states, our representation can be used to compute the set N of states one transition away from the states in T in optimal time O(jTj + jNj). McNaughton and Yamada's NFA requires (jTj jNj) in the worst case. Using Thompson's NFA, the equivalent calculation requires (r) time in the worst case. An implementation of our NFA representation con rms that it takes up an order of magnitude less space than McNaughton and Yamada's machine. An implementation to produce a DFA from our NFA representation by subset construction shows linear and quadratic speedups over subset construction starting from both Thompson's and McNaughton and Yamada's NFA's. It also shows that the DFA produced from our NFA is as much as one order of magnitude smaller than DFA's constructed from the two other NFA's.

2017 IEEE 10th Conference on Service-Oriented Computing and Applications (SOCA), 2017

Generally, the environmental wind speeds in urban areas are relatively low due to clustered build... more Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

Die vorliegende Erfindung bezieht sich auf ein Szenenaufbausystem und -verfahren durch Szenenauss... more Die vorliegende Erfindung bezieht sich auf ein Szenenaufbausystem und -verfahren durch Szenenausschnitte sowie deren Aufzeichnungsmedien. Das System weist einen Medienanbieter, einen Metadaten-Server, einen Szenen-Server und Endgerate auf. Der Medienanbieter stellt die Mediendaten zur Verfugung. Der Metadaten-Server stellt Szenenzeitdaten, die den Wiedergabeszenen der Mediendaten entsprechen, zur Verfugung. Das Endgerat besorgt sich die Mediendaten und die zugehorigen Szenenzeitdaten, und holt durch die bei der Medienwiedergabe eingegebenen Abrufzeitdaten aus den Szenenzeitdaten mindestens einen Zielszenenzeitpunkt. Der Szenen-Server bekommt Mediendaten und mindestens einen Zielszenenzeitpunkt ubermittelt, und entnimmt den Mediendaten die Teilszenenausschnitte durch den Vergleich der Zielszenenzeitdaten mit allen Szenenzeitdaten zur Generierung der Mediensegmentdaten.

International Journal of Energy Research, 2020

Scientific Reports, 2019

Dipeptidyl peptidase IV (DPP IV) is a surface glycoprotein that can degrade glucagon like pepetid... more Dipeptidyl peptidase IV (DPP IV) is a surface glycoprotein that can degrade glucagon like pepetide-1 (GLP-1) by decreasing blood sugar. Herbal medicines for diabetic therapy are widely used with acceptable efficacy but unsatisfied in advances. DPP IV was chosen as a template to employ molecular docking via Discovery Studio to search for natural phenolic compounds whether they have the inhibitory function of DPP IV. Then, docking candidates were validated and further performed signal pathway via Caco-2, C2C12, and AR42J cells. Lastly, a diet-induced diabetes in mice were applied to examine the efficacy and toxicity of hit natural phenolic products in long-term use (in vivo). After screening, curcumin, syringic acid, and resveratrol were found in high affinity with DPP IV enzymes. In enzymatic tests, curcumin and resveratrol showed potential inhibition of DPP IV. In vitro assays, curcumin inhibited of DPP IV activity in Caco-2 cells and ERK phosphorylation in C2C12 cells. Additionally...

Therapeutic Advances in Chronic Disease, 2019

Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, co... more Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, contains two forms and it can exert various physiological functions particular in controlling blood glucose through the action of GLP-1. In diabetic use, the DPP-4 inhibitor can block the DDP-4 to attenuate GLP-1 degradation and prolong GLP-1 its action and sensitize insulin activity for the purpose of lowering blood glucose. Nonetheless the adverse effects of DPP-4 inhibitors severely hinder their clinical applications, and notably there is a clinical demand for novel DPP-4 inhibitors from various sources including chemical synthesis, herbs, and plants with fewer side effects. In this review, we highlight various strategies, namely computational biology ( in silico), in vitro enzymatic and cell assays, and in vivo animal tests, for seeking natural DPP-4 inhibitors from botanic sources including herbs and plants. The pros and cons of all approaches for new inhibitor candidates or hits will...

Journal of Cell Science, 2018

The primary cilium is a tiny cell protrusion known to transduce key extracellular signals, includ... more The primary cilium is a tiny cell protrusion known to transduce key extracellular signals, including the sonic hedgehog pathway, which activates Gli transcription factors for various cellular functions. To understand the significance of Gli2 transcription factor in fibroblasts, we establish a Gli2 knockout NIH3T3 cell line by CRISPR/Cas9 technology. Surprisingly, NIH3T3 fibroblasts lacking Gli2 expression through gene knockout or RNA interference possess longer primary cilia after stimulation of ciliogenesis by serum starvation. This lengthening of primary cilia is associated with enhanced autophagy-mediated Ofd1 degradation and can be reversed by pharmacological and genetic inhibition of autophagy. Meanwhile, flow cytometry reveals that Gli2−/− NIH3T3 fibroblasts exhibit a delay in cell cycle re-entry after serum re-stimulation. Ablation of their primary cilia by Kif3a knockdown rescues the delay in cell cycle re-entry. These results suggest that Gli2 plays an unexpected role for c...

Cerebral cortex (New York, N.Y. : 1991), Jan 12, 2018

The primary cilium in neural stem cells plays distinct roles in different stages during cortical ... more The primary cilium in neural stem cells plays distinct roles in different stages during cortical development. Ciliary dysfunctions in human (i.e., ciliopathy) cause developmental defects in multiple organs, including brain developmental delays, which lead to intellectual disabilities and cognitive deficits. However, effective treatment to this devastating developmental disorder is still lacking. Here, we first investigated the effects of ciliopathy on neural stem cells by knocking down Kif3a, a kinesin II motor required for ciliogenesis, in the neurogenic stage of cortical development by in utero electroporation of mouse embryos. Brains electroporated with Kif3a shRNA showed defects in neuronal migration and differentiation, delays in neural stem cell cycle progression, and failures in interkinetic nuclear migration. Interestingly, introduction of Gli1 and Gli2 both can restore the cell cycle progression by elevating cyclin D1 in neural stem cells. Remarkably, enforced Gli2 expressi...

Molecules (Basel, Switzerland), Jan 5, 2018

The inhibition of α-glucosidase and α-amylase is a clinical strategy for the treatment of type II... more The inhibition of α-glucosidase and α-amylase is a clinical strategy for the treatment of type II diabetes, and herbal medicines have been reported to credibly alleviate hyperglycemia. Our previous study has reported some constituents from plant or herbal sources targeted to α-glucosidase and α-amylase via molecular docking and enzymatic measurement, but the hypoglycemic potencies in cell system and mice have not been validated yet. This study was aimed to elucidate the hypoglycemic efficacy of docking selected compounds in cell assay and oral glucose and starch tolerance tests of mice. All test compounds showed the inhibition of α-glucosidase activity in Caco-2 cells. The decrease of blood sugar levels of test compounds in 30 min and 60 min of mice after OGTT and OSTT, respectively and the decreased glucose levels of test compounds were significantly varied in acarbose. Taken altogether, in vitro and in vivo experiments suggest that selected natural compounds (curcumin, antroquinon...

Materials Letters, 2017

Ge doped Cu 3 SbSe 4 semiconductors with Cu deficiencies were synthesized by melting and spark pl... more Ge doped Cu 3 SbSe 4 semiconductors with Cu deficiencies were synthesized by melting and spark plasma sintering for the investigation of their thermoelectric transport properties. Ge atoms can successfully substitute Sb lattice sites, and result in lattice shrinkage with increasing Ge content. Doping with Ge not only improves the electrical conductivity but also optimizes the power factor of Cu 2.95 (Sb 1−x Ge x)Se 4. Ge doped specimens also reveal a competition between alloying effects and increased carrier thermal conductivity. The zT enhancement of Ge doped alloys is mainly ascribed to the enhanced power factor and the reduced lattice thermal conductivity. As a result, Cu 2.95 (Sb 0.96 Ge 0.04)Se 4 reaches a maximum zT of 0.7 at 640 K, showing an approximately 35% enhancement over the pristine Cu 2.95 SbSe 4 .

Proceedings of IEEE Singapore International Conference on Networks and International Conference on Information Engineering '95

ABSTRACT In this paper, we present a new real-time file system architecture which is optimized fo... more ABSTRACT In this paper, we present a new real-time file system architecture which is optimized for supporting continuous media recording in video conference applications. We show that this new design optimizes simultaneously several performance criteria, i.e., minimum buffer size, maximum I/O bandwidth utilization, maximum I/O throughput, minimum I/O latency and minimum response time. Design of this file system is based on mathematical analysis of a FCFS I/O server for streams of continuous media. It uses a reservation-based admission control algorithm to manage system resources, i.e., I/O bandwidth, buffers, and disk space. Theoretical performance guarantees are given. Preliminary experiments on PC 486's running Unix SVR4.0 version 4.0 with a slightly modified file system illustrate promising results

1995 IEEE International Conference on Systems, Man and Cybernetics. Intelligent Systems for the 21st Century

ABSTRACT In this paper, the design and implementation of a video conference recorder on an inexpe... more ABSTRACT In this paper, the design and implementation of a video conference recorder on an inexpensive PC is described. The recorder can simultaneously record several video and audio (A/V) streams in Unix file format. The objectives of the file system design are high throughput and low loss rate. A hard disk device driver and a file system are modified and tuned for A/V recording. The new file system can have up to 60% performance improvement over the traditional file system. Performance results from our experiments are presented and discussed in the paper

SIAM Journal on Computing, 1991

The problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclid... more The problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclidean space is considered. The diameter of a spanning tree is the maximum distance between any two points in the tree. A characterization of an MDST is given and a theta(n3)\theta (n^3)theta(n3)-time ...

IEEE Transactions on Wireless Communications, 2010

IEEE Transactions on Consumer Electronics, 1996

In this paper, the design and implementation of a video conference recorder on an inexpensive PC ... more In this paper, the design and implementation of a video conference recorder on an inexpensive PC is described. The recorder can simultaneously record several video and audio (A/V) streams in Unix file format. The objectives of the file system design are high throughput and low loss rate. A hard disk device driver and a file system are modified and tuned for A/V recording. The new file system can have up to 60% performance improvement over the traditional file system. Performance results from our experiments are presented and discussed in the paper.

We show how to turn a regular expression into an O(s) space representation of McNaughton and Yama... more We show how to turn a regular expression into an O(s) space representation of McNaughton and Yamada's NFA, where s is the number of NFA states. The standard adjacency list representation of McNaughton and Yamada's NFA takes up s+s 2 space in the worst case. The adjacency list representation of the NFA produced by Thompson takes up between 2r and 5r space, where r s in general, and can be arbitrarily larger than s. Given any set T of NFA states, our representation can be used to compute the set N of states one transition away from the states in T in optimal time O(jTj + jNj). McNaughton and Yamada's NFA requires (jTj jNj) in the worst case. Using Thompson's NFA, the equivalent calculation requires (r) time in the worst case. An implementation of our NFA representation con rms that it takes up an order of magnitude less space than McNaughton and Yamada's machine. An implementation to produce a DFA from our NFA representation by subset construction shows linear and quadratic speedups over subset construction starting from both Thompson's and McNaughton and Yamada's NFA's. It also shows that the DFA produced from our NFA is as much as one order of magnitude smaller than DFA's constructed from the two other NFA's.

2017 IEEE 10th Conference on Service-Oriented Computing and Applications (SOCA), 2017

Generally, the environmental wind speeds in urban areas are relatively low due to clustered build... more Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

Die vorliegende Erfindung bezieht sich auf ein Szenenaufbausystem und -verfahren durch Szenenauss... more Die vorliegende Erfindung bezieht sich auf ein Szenenaufbausystem und -verfahren durch Szenenausschnitte sowie deren Aufzeichnungsmedien. Das System weist einen Medienanbieter, einen Metadaten-Server, einen Szenen-Server und Endgerate auf. Der Medienanbieter stellt die Mediendaten zur Verfugung. Der Metadaten-Server stellt Szenenzeitdaten, die den Wiedergabeszenen der Mediendaten entsprechen, zur Verfugung. Das Endgerat besorgt sich die Mediendaten und die zugehorigen Szenenzeitdaten, und holt durch die bei der Medienwiedergabe eingegebenen Abrufzeitdaten aus den Szenenzeitdaten mindestens einen Zielszenenzeitpunkt. Der Szenen-Server bekommt Mediendaten und mindestens einen Zielszenenzeitpunkt ubermittelt, und entnimmt den Mediendaten die Teilszenenausschnitte durch den Vergleich der Zielszenenzeitdaten mit allen Szenenzeitdaten zur Generierung der Mediensegmentdaten.

International Journal of Energy Research, 2020

Scientific Reports, 2019

Dipeptidyl peptidase IV (DPP IV) is a surface glycoprotein that can degrade glucagon like pepetid... more Dipeptidyl peptidase IV (DPP IV) is a surface glycoprotein that can degrade glucagon like pepetide-1 (GLP-1) by decreasing blood sugar. Herbal medicines for diabetic therapy are widely used with acceptable efficacy but unsatisfied in advances. DPP IV was chosen as a template to employ molecular docking via Discovery Studio to search for natural phenolic compounds whether they have the inhibitory function of DPP IV. Then, docking candidates were validated and further performed signal pathway via Caco-2, C2C12, and AR42J cells. Lastly, a diet-induced diabetes in mice were applied to examine the efficacy and toxicity of hit natural phenolic products in long-term use (in vivo). After screening, curcumin, syringic acid, and resveratrol were found in high affinity with DPP IV enzymes. In enzymatic tests, curcumin and resveratrol showed potential inhibition of DPP IV. In vitro assays, curcumin inhibited of DPP IV activity in Caco-2 cells and ERK phosphorylation in C2C12 cells. Additionally...

Therapeutic Advances in Chronic Disease, 2019

Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, co... more Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, contains two forms and it can exert various physiological functions particular in controlling blood glucose through the action of GLP-1. In diabetic use, the DPP-4 inhibitor can block the DDP-4 to attenuate GLP-1 degradation and prolong GLP-1 its action and sensitize insulin activity for the purpose of lowering blood glucose. Nonetheless the adverse effects of DPP-4 inhibitors severely hinder their clinical applications, and notably there is a clinical demand for novel DPP-4 inhibitors from various sources including chemical synthesis, herbs, and plants with fewer side effects. In this review, we highlight various strategies, namely computational biology ( in silico), in vitro enzymatic and cell assays, and in vivo animal tests, for seeking natural DPP-4 inhibitors from botanic sources including herbs and plants. The pros and cons of all approaches for new inhibitor candidates or hits will...

Journal of Cell Science, 2018

The primary cilium is a tiny cell protrusion known to transduce key extracellular signals, includ... more The primary cilium is a tiny cell protrusion known to transduce key extracellular signals, including the sonic hedgehog pathway, which activates Gli transcription factors for various cellular functions. To understand the significance of Gli2 transcription factor in fibroblasts, we establish a Gli2 knockout NIH3T3 cell line by CRISPR/Cas9 technology. Surprisingly, NIH3T3 fibroblasts lacking Gli2 expression through gene knockout or RNA interference possess longer primary cilia after stimulation of ciliogenesis by serum starvation. This lengthening of primary cilia is associated with enhanced autophagy-mediated Ofd1 degradation and can be reversed by pharmacological and genetic inhibition of autophagy. Meanwhile, flow cytometry reveals that Gli2−/− NIH3T3 fibroblasts exhibit a delay in cell cycle re-entry after serum re-stimulation. Ablation of their primary cilia by Kif3a knockdown rescues the delay in cell cycle re-entry. These results suggest that Gli2 plays an unexpected role for c...

Cerebral cortex (New York, N.Y. : 1991), Jan 12, 2018

The primary cilium in neural stem cells plays distinct roles in different stages during cortical ... more The primary cilium in neural stem cells plays distinct roles in different stages during cortical development. Ciliary dysfunctions in human (i.e., ciliopathy) cause developmental defects in multiple organs, including brain developmental delays, which lead to intellectual disabilities and cognitive deficits. However, effective treatment to this devastating developmental disorder is still lacking. Here, we first investigated the effects of ciliopathy on neural stem cells by knocking down Kif3a, a kinesin II motor required for ciliogenesis, in the neurogenic stage of cortical development by in utero electroporation of mouse embryos. Brains electroporated with Kif3a shRNA showed defects in neuronal migration and differentiation, delays in neural stem cell cycle progression, and failures in interkinetic nuclear migration. Interestingly, introduction of Gli1 and Gli2 both can restore the cell cycle progression by elevating cyclin D1 in neural stem cells. Remarkably, enforced Gli2 expressi...

Molecules (Basel, Switzerland), Jan 5, 2018

The inhibition of α-glucosidase and α-amylase is a clinical strategy for the treatment of type II... more The inhibition of α-glucosidase and α-amylase is a clinical strategy for the treatment of type II diabetes, and herbal medicines have been reported to credibly alleviate hyperglycemia. Our previous study has reported some constituents from plant or herbal sources targeted to α-glucosidase and α-amylase via molecular docking and enzymatic measurement, but the hypoglycemic potencies in cell system and mice have not been validated yet. This study was aimed to elucidate the hypoglycemic efficacy of docking selected compounds in cell assay and oral glucose and starch tolerance tests of mice. All test compounds showed the inhibition of α-glucosidase activity in Caco-2 cells. The decrease of blood sugar levels of test compounds in 30 min and 60 min of mice after OGTT and OSTT, respectively and the decreased glucose levels of test compounds were significantly varied in acarbose. Taken altogether, in vitro and in vivo experiments suggest that selected natural compounds (curcumin, antroquinon...

Materials Letters, 2017

Ge doped Cu 3 SbSe 4 semiconductors with Cu deficiencies were synthesized by melting and spark pl... more Ge doped Cu 3 SbSe 4 semiconductors with Cu deficiencies were synthesized by melting and spark plasma sintering for the investigation of their thermoelectric transport properties. Ge atoms can successfully substitute Sb lattice sites, and result in lattice shrinkage with increasing Ge content. Doping with Ge not only improves the electrical conductivity but also optimizes the power factor of Cu 2.95 (Sb 1−x Ge x)Se 4. Ge doped specimens also reveal a competition between alloying effects and increased carrier thermal conductivity. The zT enhancement of Ge doped alloys is mainly ascribed to the enhanced power factor and the reduced lattice thermal conductivity. As a result, Cu 2.95 (Sb 0.96 Ge 0.04)Se 4 reaches a maximum zT of 0.7 at 640 K, showing an approximately 35% enhancement over the pristine Cu 2.95 SbSe 4 .

Proceedings of IEEE Singapore International Conference on Networks and International Conference on Information Engineering '95

ABSTRACT In this paper, we present a new real-time file system architecture which is optimized fo... more ABSTRACT In this paper, we present a new real-time file system architecture which is optimized for supporting continuous media recording in video conference applications. We show that this new design optimizes simultaneously several performance criteria, i.e., minimum buffer size, maximum I/O bandwidth utilization, maximum I/O throughput, minimum I/O latency and minimum response time. Design of this file system is based on mathematical analysis of a FCFS I/O server for streams of continuous media. It uses a reservation-based admission control algorithm to manage system resources, i.e., I/O bandwidth, buffers, and disk space. Theoretical performance guarantees are given. Preliminary experiments on PC 486's running Unix SVR4.0 version 4.0 with a slightly modified file system illustrate promising results

1995 IEEE International Conference on Systems, Man and Cybernetics. Intelligent Systems for the 21st Century

ABSTRACT In this paper, the design and implementation of a video conference recorder on an inexpe... more ABSTRACT In this paper, the design and implementation of a video conference recorder on an inexpensive PC is described. The recorder can simultaneously record several video and audio (A/V) streams in Unix file format. The objectives of the file system design are high throughput and low loss rate. A hard disk device driver and a file system are modified and tuned for A/V recording. The new file system can have up to 60% performance improvement over the traditional file system. Performance results from our experiments are presented and discussed in the paper

SIAM Journal on Computing, 1991

The problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclid... more The problem of finding a minimum diameter spanning tree (MDST) of a set of n points in the Euclidean space is considered. The diameter of a spanning tree is the maximum distance between any two points in the tree. A characterization of an MDST is given and a theta(n3)\theta (n^3)theta(n3)-time ...

IEEE Transactions on Wireless Communications, 2010

IEEE Transactions on Consumer Electronics, 1996

In this paper, the design and implementation of a video conference recorder on an inexpensive PC ... more In this paper, the design and implementation of a video conference recorder on an inexpensive PC is described. The recorder can simultaneously record several video and audio (A/V) streams in Unix file format. The objectives of the file system design are high throughput and low loss rate. A hard disk device driver and a file system are modified and tuned for A/V recording. The new file system can have up to 60% performance improvement over the traditional file system. Performance results from our experiments are presented and discussed in the paper.