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Ship collision avoidance route planning using CRI-based A<sup>*</sup> algorithm
Chanhee Seo,Yoojeong Noh,Misganaw Abebe,Young-Jin Kang,Sunyoung Park,Cheolhyeon Kwon The Society of Naval Architects of Korea 2023 International Journal of Naval Architecture and Oc Vol.15 No.-
This study presents a novel ship route planning algorithm that takes into account both operational economy and safety by integrating the A<sup>*</sup> algorithm with a collision avoidance algorithm that evaluates the Collision Risk Index (CRI) between the own ship and the target ship. The CRI-based A<sup>*</sup> algorithm defines a penalty zone, allowing the own ship to explore safe routes based on the International Regulations for Preventing Collisions at Sea 1972 (COLREGs) and performs an adaptive and effective node search on an extended local map grid according to various encounter situations. The proposed algorithm is validated through simulations of head-on, fine-broad crossing, converging crossing, and overtaking encounters, indicating an economical and safe optimum route compared to conventional ship domain-based route planning.
유한요소법과 모드중첩법을 이용한 하드디스크 드라이브의 회전 디스크-스핀들 시스템에 대한 강제 진동 해석
서찬희(Chanhee Seo),장건희(Gunhee Jang),이호성(Hosung Lee) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This paper presents a method to analyze the forced vibration of a rotating disk-spindle system in a HDD with fluid dynamic bearings (FDBs) and complicated base structure by using FEM and mode superposition. The validity of the proposed method is verified by comparing the simulated time and frequency responses with the experimental results. When the base plate is excited, it shows that pure disk modes cannot be excited and that rocking modes can be damped out due to the sufficient damping effect of FDBs.
CRI와 COLREG를 이용한 선박 충돌 회피 알고리즘
서찬희(Chanhee Seo),노유정(Yoojeong Noh),미쓰가나 아베베 바예(Misganaw Abebe Baye) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
In recent years, unmanned shipping of ships has continued to evolve and has come to be considered commercially viable. Path planning is an important process for unmanned operations. However, there are many variables at sea. And they should be considered when routing for economy and safety. This study aims to ensure the economics and safety of ships ’operation by adding collision avoidance algorithm to an improved A<SUP>*</SUP> algorithm, a ships’ route finding optimization algorithm considering the economics of operations. For this, the algorithm is constrained by applying the Collision Risk Index (CRI) and COLREGs rule to the path optimization algorithm. To validate the proposed algorithm, The collision avoidance algorithm was performed in various maritime traffic scenarios, and the results of using CRI were compared to those using other ship domain methods.
Seo, Hwi Won,Han, Kiwon,Kim, Duyeol,Oh, Yeonsu,Kang, Ikjae,Park, Changhoon,Jang, Hyun,Chae, Chanhee American Society for Microbiology 2011 Clinical and vaccine immunology Vol.18 No.7
<B>ABSTRACT</B><P>The objective of the present study was to determine the effect of an inactivated porcine circovirus type 2 (PCV2) vaccine on PCV2b virus shedding in the semen of experimentally infected boars by measuring the immunological response and the PCV2b DNA load in blood and semen. Twelve boars were randomly divided into three groups. The boars in group 1 (<I>n</I>= 4) were immunized with an inactivated PCV2 vaccine and were challenged with PCV2b. The boars in group 2 (<I>n</I>= 4) were only challenged with PCV2b. The boars in group 3 (<I>n</I>= 4) served as negative controls. The number of PCV2 genome copies of PCV2 in the serum and semen were significantly lower in vaccinated challenged boars than in nonvaccinated challenged boars at 7, 10, 14, 21, 32, 35, 42, 49, and 60 days postinoculation. The number of PCV2b genomes in the semen correlated with the number of PCV2b genomes in the blood in both vaccinated challenged (<I>R</I>= 0.714) and nonvaccinated challenged (<I>R</I>= 0.861) boars. The results of the present study demonstrate that the inactivated PCV2 vaccine significantly decreases the amount of PCV2b DNA shedding in semen from vaccinated boars after experimental infection with PCV2b.</P>