Bui Anh - Academia.edu (original) (raw)

Papers by Bui Anh

Research paper thumbnail of Sự Thay Đổi Của Vai Trò Giảng Viên Trong Thời Đại Số – Một Nghiên Cứu Tại Trường Đại Học Nguyễn Tất Thành

Tạp chí Khoa học

Cùng với sự phát triển của công nghệ thông tin và truyền thông, sự xuất hiện và thâm nhập của c... more Cùng với sự phát triển của công nghệ thông tin và truyền thông, sự xuất hiện và thâm nhập của công nghệ số trong toàn bộ hệ thống giáo dục đã tạo ra các thách thức đối với các tổ chức giáo dục đại học trong việc xác định lại vai trò giảng viên. Phương pháp nghiên cứu định tính được tiếp cận nhằm giải thích các quan điểm lí thuyết và trả lời các câu hỏi nghiên cứu. Dữ liệu được thu thập dựa trên các nghiên cứu trước đó và các cuộc phỏng vấn bán cấu trúc với 11 giảng viên tại Trường Đại học Nguyễn Tất Thành. Từ các dữ liệu thu thập được, nhóm nghiên cứu tiến hành giải băng, mã hóa và phân tích, từ đó khám phá vai trò của giảng viên trong thời đại số. Kết quả nghiên cứu cho thấy vai trò giảng viên thay đổi ở 3 nhóm chính: i) vai trò giảng viên thay đổi trong việc chuẩn bị bài giảng; ii) vai trò giảng viên thay đổi trong việc giảng dạy trên lớp; và iii) vai trò giảng viên thay đổi trong việc hỗ trợ sinh viên.

Research paper thumbnail of In vitro propagation of Xao tam phan (Paramignya trimera (Oliv.) Guill.)

Science and Technology Development Journal - Natural Sciences, 2017

Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", ha... more Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", has been used in Vietnamese folk for the treatment of numerous cancers. Due to word of mouth about the anticancer properties of this plant, its stems and roots have been overexploited leading to the serious decline of this species in Phu Yen, Khanh Hoa and Ninh Thuan provinces. The aim of the study was to establish an in vitro propagation protocol for the conservation of P. trimera. In this research shoot clusters (5–8 shoots/cluster) were regenerated from axillary bud explants of 1–3 year-old trees after 3 months of cultures on the WPM (woody plant medium) supplemented with STS 3 and BA 5–7 mg/L. STS (silver thiosulfate) was used to prevent the leaf abscission. These shoot clusters grew slowly and reached 1–3 cm in heights after 4 months of the cultures. These shoot clusters did not form any roots after 2 months of culture on the rooting media with IBA and/or NAA 1–5 mg/L. However, there ...

Research paper thumbnail of The Robustness of Strong Stability of Positive Homogeneous Difference Equations

Journal of Applied Mathematics, 2008

We study the robustness of strong stability of the homogeneous difference equation via the concep... more We study the robustness of strong stability of the homogeneous difference equation via the concept of strong stability radii: complex, real and positive radii in this paper. We also show that in the case of positive systems, these radii coincide. Finally, a simple example is given.

Research paper thumbnail of Weighted BMO spaces associated to operators

Research paper thumbnail of Notes on boundedness of spectral multipliers on Hardy spaces associated to operators

Nagoya Mathematical Journal, 2011

Let L be a nonnegative self-adjoint operator on L2 (X), where X is a space of homogeneous type. A... more Let L be a nonnegative self-adjoint operator on L2 (X), where X is a space of homogeneous type. Assume that L generates an analytic semigroup e–tl whose kernel satisfies the standard Gaussian upper bounds. We prove that the spectral multiplier F(L) is bounded on for 0 < p < 1, the Hardy space associated to operator L, when F is a suitable function.

Research paper thumbnail of Implementing CCTV-Based Attendance Taking Support System Using Deep Face Recognition: A Case Study at FPT Polytechnic College

Symmetry, 2020

Face recognition (FR) has received considerable attention in the field of security, especially in... more Face recognition (FR) has received considerable attention in the field of security, especially in the use of closed-circuit television (CCTV) cameras in security monitoring. Although significant advances in the field of computer vision are made, advanced face recognition systems provide satisfactory performance only in controlled conditions. They deteriorate significantly in the face of real-world scenarios such as lighting conditions, motion blur, camera resolution, etc. This article shows how we design, implement, and conduct the empirical comparisons of machine learning open libraries in building attendance taking (AT) support systems using indoor security cameras called ATSS. Our trial system was deployed to record the appearances of 120 students in five classes who study on the third floor of FPT Polytechnic College building. Our design allows for flexible system scaling, and it is not only usable for a school but a generic attendance system with CCTV. The measurement results s...

Research paper thumbnail of A Computer-Vision Based Application for Student Behavior Monitoring in Classroom

Applied Sciences, 2019

Automated learning analytics is becoming an essential topic in the educational area, which needs ... more Automated learning analytics is becoming an essential topic in the educational area, which needs effective systems to monitor the learning process and provides feedback to the teacher. Recent advances in visual sensors and computer vision methods enable automated monitoring of behavior and affective states of learners at different levels, from university to pre-school. The objective of this research was to build an automatic system that allowed the faculties to capture and make a summary of student behaviors in the classroom as a part of data acquisition for the decision making process. The system records the entire session and identifies when the students pay attention in the classroom, and then reports to the facilities. Our design and experiments show that our system is more flexible and more accurate than previously published work.

Research paper thumbnail of Effect of Bagging Time on Fruit Yield and Quality of Red Pitaya (Hylocereus spp.) Fruit in Vietnam

International Journal of Plant & Soil Science, 2017

The study was performed to evaluate the effect of bagging time on fruit yield and quality of red ... more The study was performed to evaluate the effect of bagging time on fruit yield and quality of red pitaya H14 cultivar from May to

Research paper thumbnail of Field Survey and Comparative Study of Pteris Vittata and Pityrogramma Calomelanos Grown on Arsenic Contaminated Lands with Different Soil pH

Bulletin of environmental contamination and toxicology, Jan 20, 2018

In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) cont... more In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) contaminated areas with soil pH 7.2-8.8 and 2.3-4.2, respectively. In the first pot experiment, two fern species were grown on the soil amended with 300 mg kgAs at soil pH of 5.1, 7.2 and 9. P. calomelanos survived all pH treatments, and had the highest frond As concentration and soil As removal efficiency at soil pH 5.1. All P. vittata plants were dead at soil pH 5.1. P. vittata had higher frond As concentration, biomass and the amount of As removed from the soil than those of P. calomelanos at soil pH of 7.2 and 9. In the second pot experiment, P. vittata was demonstrated to have greater life time, biomass, As tolerance and accumulation than those of P. calomelanos as planted on alkaline soil (pH 7.8) spiked with various concentrations of As.

Research paper thumbnail of Phytoremediation potential of indigenous plants from Thai Nguyen province, Vietnam

Journal of environmental biology / Academy of Environmental Biology, India, 2011

This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 i... more This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 indigenous plants and 12 soil in-situ plant samples in Thai Nguyen Province, Vietnam. The results showed that the soils of surveyed mining areas contained 181.2- 6754.3 mg kg(-1) As, 235.5-4337.2 mg kg(-1) Pb, 0.8- 419 mg kg(-1) Cd and 361.8-17565.1 mg kg(-1) Zn depending on the characteristics of each mining site. These values are much higher than those typical for normal soil. The heavy metal uptake into shoots and roots of 33 indigenous plant species was also determined. Two species of the plants investigated, Pteris vittata L. and Pityrogramma calomelanos L. were As hyperaccumulators, containing more than 0.1% heavy metals in their shoots. Eleusine indica L., Cynodon dactylon L., Cyperus rotundus L. and Equisetum ramosissimum (Vauch) accumulate very high Pb (0.15-0.65%) and Zn (0.22-1.56%) concentration in their roots. Additional experiments to clarify the potential of six these plant...

Research paper thumbnail of Stability radii of positive linear time-delay systems under fractional perturbations

Systems & Control Letters, 2009

In this paper we study stability radii of positive linear delay systems under fractional perturba... more In this paper we study stability radii of positive linear delay systems under fractional perturbations. It is shown that the three stability radii: complex, real and positive stability radii coincide and can be computed by a simple formula. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Effect of Milletia ichthyochtona Drake Solution on Cabbage Production Components

International Journal of Plant & Soil Science, 2014

The study was performed to evaluate the efficiency of Milletia ichthyochtona Drake solution on co... more The study was performed to evaluate the efficiency of Milletia ichthyochtona Drake solution on control of insect pests in cabbage crop. Milletia ichthyochtona Drake solution, Soap 0.1% was sprayed at 15, 35 and 45 days after transplanting. The effect of all treatments on cabbage growth was measured. The leaf number, head diameter, head weight and quality of cabbage vegetable were recorded. The efficiency of Milletia ichthyochtona Drake solution, Soap 0.1% on cabbage insect pests was measured. Results showed that sprayed with Milletia ichthyochtona Drake solution, Soap 0.1% was

Research paper thumbnail of Robust stability of a class of positive quasi-polynomials in Banach spaces

Mathematical Notes, 2010

Abstract In this paper, we study the stability radii of positive quasipolynomials associated with... more Abstract In this paper, we study the stability radii of positive quasipolynomials associated with linear functional difference equations in infinite-dimensional spaces. It is shown that the positive, real and complex stability radii coincide. Moreover, explicit formulas are derived ...

Research paper thumbnail of A Perron-Frobenius theorem for positive polynomial operators in Banach lattices

Positivity, 2009

In this paper, we extend the Perron-Frobenius theorem for positive polynomial operators in Banach... more In this paper, we extend the Perron-Frobenius theorem for positive polynomial operators in Banach lattices. The result obtained is applied to derive necessary and sufficient conditions for the stability of positive polynomial operators. Then we study stability radii: complex, real and positive radii of positive polynomial operators and show that in this case the three radii coincide and can be computed by a simple formula. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Robust stability of positive linear systems in Banach spaces

Journal of Difference Equations and Applications, 2010

In this paper, we study the stability radii of positive linear systems with delays with respect t... more In this paper, we study the stability radii of positive linear systems with delays with respect to various classes of perturbations in infinite dimensional spaces. It is shown that the positive, real and complex stability radii coincide. Moreover, explicit formulas are derived for these stability radii and illustrated by a simple example.

Research paper thumbnail of A Perron-Frobenius Theorem for Positive Quasipolynomial Matrices Associated with Homogeneous Difference Equations

Journal of Applied Mathematics, 2007

We extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated... more We extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated with homogeneous difference equations. Finally, the result obtained is applied to derive necessary and sufficient conditions for the stability of positive system.

Research paper thumbnail of Robust stability of Metzler operators under parameter perturbations

International Journal of Robust and Nonlinear Control, 2009

In this paper we study how the spectral bound of Metzler operators changes under parameter pertur... more In this paper we study how the spectral bound of Metzler operators changes under parameter perturbations. Characterizations of the stability radii of Metzler operator with respect to this type of disturbances are established. The results generalize those obtained in (Vietnam

Research paper thumbnail of Stability radii of positive linear systems under fractional perturbations

International Journal of Robust and Nonlinear Control, 2009

In this paper we study stability radii of positive linear discrete-time systems under fractional ... more In this paper we study stability radii of positive linear discrete-time systems under fractional perturbations. It is shown that real and complex stability radii coincide and can be computed by a simple formula. From the obtained results, we apply to derive estimates and computable formulae for the stability radii of positive linear delay systems. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Robust stability of delay difference systems under fractional perturbations in infinite-dimensional spaces

International Journal of Control, 2009

In this article we study the robust stability of difference systems with delays under fractional ... more In this article we study the robust stability of difference systems with delays under fractional perturbations in infinite-dimensional spaces. First, the estimates of the complex stability radius are addressed. Second, it is shown that for positive linear systems, the complex, ...

Research paper thumbnail of Stability radii of delay difference systems under affine parameter perturbations in infinite dimensional spaces

Applied Mathematics and Computation, 2008

In this paper, we study the stability radii of positive difference systems with delays under arbi... more In this paper, we study the stability radii of positive difference systems with delays under arbitrary affine parameter perturbations in infinite dimensional spaces. The obtained results are extensions of the recent results in [P.H.A. Ngoc, N.K. Son, Stability radii of positive linear difference equations under affine parameter perturbation,

Research paper thumbnail of Sự Thay Đổi Của Vai Trò Giảng Viên Trong Thời Đại Số – Một Nghiên Cứu Tại Trường Đại Học Nguyễn Tất Thành

Tạp chí Khoa học

Cùng với sự phát triển của công nghệ thông tin và truyền thông, sự xuất hiện và thâm nhập của c... more Cùng với sự phát triển của công nghệ thông tin và truyền thông, sự xuất hiện và thâm nhập của công nghệ số trong toàn bộ hệ thống giáo dục đã tạo ra các thách thức đối với các tổ chức giáo dục đại học trong việc xác định lại vai trò giảng viên. Phương pháp nghiên cứu định tính được tiếp cận nhằm giải thích các quan điểm lí thuyết và trả lời các câu hỏi nghiên cứu. Dữ liệu được thu thập dựa trên các nghiên cứu trước đó và các cuộc phỏng vấn bán cấu trúc với 11 giảng viên tại Trường Đại học Nguyễn Tất Thành. Từ các dữ liệu thu thập được, nhóm nghiên cứu tiến hành giải băng, mã hóa và phân tích, từ đó khám phá vai trò của giảng viên trong thời đại số. Kết quả nghiên cứu cho thấy vai trò giảng viên thay đổi ở 3 nhóm chính: i) vai trò giảng viên thay đổi trong việc chuẩn bị bài giảng; ii) vai trò giảng viên thay đổi trong việc giảng dạy trên lớp; và iii) vai trò giảng viên thay đổi trong việc hỗ trợ sinh viên.

Research paper thumbnail of In vitro propagation of Xao tam phan (Paramignya trimera (Oliv.) Guill.)

Science and Technology Development Journal - Natural Sciences, 2017

Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", ha... more Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", has been used in Vietnamese folk for the treatment of numerous cancers. Due to word of mouth about the anticancer properties of this plant, its stems and roots have been overexploited leading to the serious decline of this species in Phu Yen, Khanh Hoa and Ninh Thuan provinces. The aim of the study was to establish an in vitro propagation protocol for the conservation of P. trimera. In this research shoot clusters (5–8 shoots/cluster) were regenerated from axillary bud explants of 1–3 year-old trees after 3 months of cultures on the WPM (woody plant medium) supplemented with STS 3 and BA 5–7 mg/L. STS (silver thiosulfate) was used to prevent the leaf abscission. These shoot clusters grew slowly and reached 1–3 cm in heights after 4 months of the cultures. These shoot clusters did not form any roots after 2 months of culture on the rooting media with IBA and/or NAA 1–5 mg/L. However, there ...

Research paper thumbnail of The Robustness of Strong Stability of Positive Homogeneous Difference Equations

Journal of Applied Mathematics, 2008

We study the robustness of strong stability of the homogeneous difference equation via the concep... more We study the robustness of strong stability of the homogeneous difference equation via the concept of strong stability radii: complex, real and positive radii in this paper. We also show that in the case of positive systems, these radii coincide. Finally, a simple example is given.

Research paper thumbnail of Weighted BMO spaces associated to operators

Research paper thumbnail of Notes on boundedness of spectral multipliers on Hardy spaces associated to operators

Nagoya Mathematical Journal, 2011

Let L be a nonnegative self-adjoint operator on L2 (X), where X is a space of homogeneous type. A... more Let L be a nonnegative self-adjoint operator on L2 (X), where X is a space of homogeneous type. Assume that L generates an analytic semigroup e–tl whose kernel satisfies the standard Gaussian upper bounds. We prove that the spectral multiplier F(L) is bounded on for 0 < p < 1, the Hardy space associated to operator L, when F is a suitable function.

Research paper thumbnail of Implementing CCTV-Based Attendance Taking Support System Using Deep Face Recognition: A Case Study at FPT Polytechnic College

Symmetry, 2020

Face recognition (FR) has received considerable attention in the field of security, especially in... more Face recognition (FR) has received considerable attention in the field of security, especially in the use of closed-circuit television (CCTV) cameras in security monitoring. Although significant advances in the field of computer vision are made, advanced face recognition systems provide satisfactory performance only in controlled conditions. They deteriorate significantly in the face of real-world scenarios such as lighting conditions, motion blur, camera resolution, etc. This article shows how we design, implement, and conduct the empirical comparisons of machine learning open libraries in building attendance taking (AT) support systems using indoor security cameras called ATSS. Our trial system was deployed to record the appearances of 120 students in five classes who study on the third floor of FPT Polytechnic College building. Our design allows for flexible system scaling, and it is not only usable for a school but a generic attendance system with CCTV. The measurement results s...

Research paper thumbnail of A Computer-Vision Based Application for Student Behavior Monitoring in Classroom

Applied Sciences, 2019

Automated learning analytics is becoming an essential topic in the educational area, which needs ... more Automated learning analytics is becoming an essential topic in the educational area, which needs effective systems to monitor the learning process and provides feedback to the teacher. Recent advances in visual sensors and computer vision methods enable automated monitoring of behavior and affective states of learners at different levels, from university to pre-school. The objective of this research was to build an automatic system that allowed the faculties to capture and make a summary of student behaviors in the classroom as a part of data acquisition for the decision making process. The system records the entire session and identifies when the students pay attention in the classroom, and then reports to the facilities. Our design and experiments show that our system is more flexible and more accurate than previously published work.

Research paper thumbnail of Effect of Bagging Time on Fruit Yield and Quality of Red Pitaya (Hylocereus spp.) Fruit in Vietnam

International Journal of Plant & Soil Science, 2017

The study was performed to evaluate the effect of bagging time on fruit yield and quality of red ... more The study was performed to evaluate the effect of bagging time on fruit yield and quality of red pitaya H14 cultivar from May to

Research paper thumbnail of Field Survey and Comparative Study of Pteris Vittata and Pityrogramma Calomelanos Grown on Arsenic Contaminated Lands with Different Soil pH

Bulletin of environmental contamination and toxicology, Jan 20, 2018

In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) cont... more In field survey, Pteris vittata and Pityrogramma calomelanos were only found in arsenic (As) contaminated areas with soil pH 7.2-8.8 and 2.3-4.2, respectively. In the first pot experiment, two fern species were grown on the soil amended with 300 mg kgAs at soil pH of 5.1, 7.2 and 9. P. calomelanos survived all pH treatments, and had the highest frond As concentration and soil As removal efficiency at soil pH 5.1. All P. vittata plants were dead at soil pH 5.1. P. vittata had higher frond As concentration, biomass and the amount of As removed from the soil than those of P. calomelanos at soil pH of 7.2 and 9. In the second pot experiment, P. vittata was demonstrated to have greater life time, biomass, As tolerance and accumulation than those of P. calomelanos as planted on alkaline soil (pH 7.8) spiked with various concentrations of As.

Research paper thumbnail of Phytoremediation potential of indigenous plants from Thai Nguyen province, Vietnam

Journal of environmental biology / Academy of Environmental Biology, India, 2011

This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 i... more This study was focused on determining Arsenic (As), Lead (Pb), Cadmium (Cd) and Zinc (Zn) in 33 indigenous plants and 12 soil in-situ plant samples in Thai Nguyen Province, Vietnam. The results showed that the soils of surveyed mining areas contained 181.2- 6754.3 mg kg(-1) As, 235.5-4337.2 mg kg(-1) Pb, 0.8- 419 mg kg(-1) Cd and 361.8-17565.1 mg kg(-1) Zn depending on the characteristics of each mining site. These values are much higher than those typical for normal soil. The heavy metal uptake into shoots and roots of 33 indigenous plant species was also determined. Two species of the plants investigated, Pteris vittata L. and Pityrogramma calomelanos L. were As hyperaccumulators, containing more than 0.1% heavy metals in their shoots. Eleusine indica L., Cynodon dactylon L., Cyperus rotundus L. and Equisetum ramosissimum (Vauch) accumulate very high Pb (0.15-0.65%) and Zn (0.22-1.56%) concentration in their roots. Additional experiments to clarify the potential of six these plant...

Research paper thumbnail of Stability radii of positive linear time-delay systems under fractional perturbations

Systems & Control Letters, 2009

In this paper we study stability radii of positive linear delay systems under fractional perturba... more In this paper we study stability radii of positive linear delay systems under fractional perturbations. It is shown that the three stability radii: complex, real and positive stability radii coincide and can be computed by a simple formula. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Effect of Milletia ichthyochtona Drake Solution on Cabbage Production Components

International Journal of Plant & Soil Science, 2014

The study was performed to evaluate the efficiency of Milletia ichthyochtona Drake solution on co... more The study was performed to evaluate the efficiency of Milletia ichthyochtona Drake solution on control of insect pests in cabbage crop. Milletia ichthyochtona Drake solution, Soap 0.1% was sprayed at 15, 35 and 45 days after transplanting. The effect of all treatments on cabbage growth was measured. The leaf number, head diameter, head weight and quality of cabbage vegetable were recorded. The efficiency of Milletia ichthyochtona Drake solution, Soap 0.1% on cabbage insect pests was measured. Results showed that sprayed with Milletia ichthyochtona Drake solution, Soap 0.1% was

Research paper thumbnail of Robust stability of a class of positive quasi-polynomials in Banach spaces

Mathematical Notes, 2010

Abstract In this paper, we study the stability radii of positive quasipolynomials associated with... more Abstract In this paper, we study the stability radii of positive quasipolynomials associated with linear functional difference equations in infinite-dimensional spaces. It is shown that the positive, real and complex stability radii coincide. Moreover, explicit formulas are derived ...

Research paper thumbnail of A Perron-Frobenius theorem for positive polynomial operators in Banach lattices

Positivity, 2009

In this paper, we extend the Perron-Frobenius theorem for positive polynomial operators in Banach... more In this paper, we extend the Perron-Frobenius theorem for positive polynomial operators in Banach lattices. The result obtained is applied to derive necessary and sufficient conditions for the stability of positive polynomial operators. Then we study stability radii: complex, real and positive radii of positive polynomial operators and show that in this case the three radii coincide and can be computed by a simple formula. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Robust stability of positive linear systems in Banach spaces

Journal of Difference Equations and Applications, 2010

In this paper, we study the stability radii of positive linear systems with delays with respect t... more In this paper, we study the stability radii of positive linear systems with delays with respect to various classes of perturbations in infinite dimensional spaces. It is shown that the positive, real and complex stability radii coincide. Moreover, explicit formulas are derived for these stability radii and illustrated by a simple example.

Research paper thumbnail of A Perron-Frobenius Theorem for Positive Quasipolynomial Matrices Associated with Homogeneous Difference Equations

Journal of Applied Mathematics, 2007

We extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated... more We extend the classical Perron-Frobenius theorem for positive quasipolynomial matrices associated with homogeneous difference equations. Finally, the result obtained is applied to derive necessary and sufficient conditions for the stability of positive system.

Research paper thumbnail of Robust stability of Metzler operators under parameter perturbations

International Journal of Robust and Nonlinear Control, 2009

In this paper we study how the spectral bound of Metzler operators changes under parameter pertur... more In this paper we study how the spectral bound of Metzler operators changes under parameter perturbations. Characterizations of the stability radii of Metzler operator with respect to this type of disturbances are established. The results generalize those obtained in (Vietnam

Research paper thumbnail of Stability radii of positive linear systems under fractional perturbations

International Journal of Robust and Nonlinear Control, 2009

In this paper we study stability radii of positive linear discrete-time systems under fractional ... more In this paper we study stability radii of positive linear discrete-time systems under fractional perturbations. It is shown that real and complex stability radii coincide and can be computed by a simple formula. From the obtained results, we apply to derive estimates and computable formulae for the stability radii of positive linear delay systems. Finally, a simple example is given to illustrate the obtained results.

Research paper thumbnail of Robust stability of delay difference systems under fractional perturbations in infinite-dimensional spaces

International Journal of Control, 2009

In this article we study the robust stability of difference systems with delays under fractional ... more In this article we study the robust stability of difference systems with delays under fractional perturbations in infinite-dimensional spaces. First, the estimates of the complex stability radius are addressed. Second, it is shown that for positive linear systems, the complex, ...

Research paper thumbnail of Stability radii of delay difference systems under affine parameter perturbations in infinite dimensional spaces

Applied Mathematics and Computation, 2008

In this paper, we study the stability radii of positive difference systems with delays under arbi... more In this paper, we study the stability radii of positive difference systems with delays under arbitrary affine parameter perturbations in infinite dimensional spaces. The obtained results are extensions of the recent results in [P.H.A. Ngoc, N.K. Son, Stability radii of positive linear difference equations under affine parameter perturbation,