Sang-Do Lee

Prof. Sang-Do Lee

Mokpo National Maritime University, Mokpo, Jeonnam, Republic of Korea
orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 February 2020 in Sensors
Verified
Journal Article
Open access
PDF file
Mai The VuMai The Vu
Mai The Vu
VMVan Mien
Van Mien
PBPhuc Bui
Phuc Bui
Do Quang ThangDo Quang Thang
Do Quang Thang
Tuan-Tu HuynhTuan-Tu Huynh
Tuan-Tu Huynh
Hyeung-Sik ChoiHyeung-Sik Choi
Hyeung-Sik Choi
This paper focuses on motion analysis of a coupled unmanned surface vehicle (USV)–umbilical cable (UC)–unmanned underwater vehicle (UUV) system to investigate the interaction behavior between the vehicles and the UC in the ocean environment. For this, a new dynamic modeling method for investigating a multi-body dynamics system of this coupling system is employed. Firstly, the structure and hardware composition of the proposed system are presented. The USV and UUV are modeled as rigid-body vehicles, and the flexible UC is discretized using the catenary equation. In order to solve the nonlinear coupled dynamics of the vehicles and flexible UC, the fourth-order Runge–Kutta numerical method is implemented. In modeling the flexible UC dynamics, the shooting method is applied to solve a two-point boundary value problem of the catenary equation. The interaction between the UC and the USV–UUV system is investigated through numerical simulations in the time domain. Through the computer simulation, the behavior of the coupled USV–UC–UUV system is analyzed for three situations which can occur. In particular, variation of the UC forces and moments at the tow points and the configuration of the UC in the water are investigated.
1

28 March 2020 in International Journal of Production Research
Verified
Journal Article
Closed access
XXXiao Xu
Xiao Xu
SLSang-Do Lee
Sang-Do Lee
HKHwan-Seong KIM
Hwan-Seong KIM
SYSam-Sang You
Sam-Sang You
This paper deals with adaptive super-twisting (STW) sliding mode control (SMC) algorithm to manage chaotic supply chain system. A multi-echelon supply chain system having parametric perturbations and disturbances is presented to demonstrate chaotic nonlinear dynamical behaviours. When changing input variables slightly in the supply chain system, the predicted outputs will be completely different due to chaotic behaviours with bifurcation. In addition, various uncertainties along with exogenous disturbances make the system dynamics more complex to manage as they propagate both upstream and downstream of the supply chain networks. Particularly, the adaptive STW SMC algorithm has been designed for chaos suppression and synchronisation of the supply chain system. Next, the robust control algorithm with adaptive law for the closed-loop system has been proved by using Lyapunov stability theorem. Then, extensive numerical simulations are conducted to demonstrate the validity of the active control synthesis for optimal operations management of chaotic supply chain networks. The control algorithm based on system theory provides satisfactory performance on achieving chaos suppression and synchronisation of the chaotic supply system. The control system theory can be expanded into new integration software applications for operations management of supply chain networks. Finally, the presented control synthesis with dynamical analysis is essential for strategic decision-makers in the modern supply chain management.

1 January 2020 in Ocean Engineering
Verified
Journal Article
Closed access
SLSang-Do Lee
Sang-Do Lee
BPBui Duc Hong Phuc
Bui Duc Hong Phuc
XXXiao Xu
Xiao Xu
SYSam-Sang You
Sam-Sang You

1 February 2022 in Journal of Ocean Engineering and Science
Verified
Journal Article
Open access
PBPhuc Duc Hong Bui
Phuc Duc Hong Bui
SYSam-Sang You
Sam-Sang You
HKHwan-Seong Kim
Hwan-Seong Kim
SLSang-Do Lee
Sang-Do Lee

1 February 2021 in Ocean Engineering
Verified
Journal Article
Closed access
SLSang-Do Lee
Sang-Do Lee
SYSam-Sang You
Sam-Sang You
XXXiao Xu
Xiao Xu
TCTruong Ngoc Cuong
Truong Ngoc Cuong

2 April 2020 in Journal of International Maritime Safety, Environmental Affairs, and Shipping
Verified
Journal Article
Open access
TCTruong Ngoc Cuong
Truong Ngoc Cuong
XXXiao Xu
Xiao Xu
SLSang-Do Lee
Sang-Do Lee
Sam-Sang YouSam-Sang You
Sam-Sang You
As world trade becomes ever more globalised and interconnected, the international maritime supply chains are experiencing challenges as well as enjoying greater business opportunities. Chaotic systems are always described by deterministic laws, however they produce completely erratic and divergent behaviors. The study of system dynamics and management strategy has been promoted to improve the efficiency and effectiveness of chaotic maritime supply chains. This paper deals with a nonlinear control theory for how to intensely explore complex dynamical behaviours in multi-echelon supply chain networks. Also, novel sliding mode controllers are designed to regulate the supply chain management to achieve the control and synchronization of chaotic behaviour of the system dynamics. Extensive numerical simulations have been conducted to validate the efficacy and reliability of the presented control algorithms for maritime supply chains under parametric perturbations and external disturbances.