S&T Text Mining을 이용한 국방 유망기술 식별에 관한 연구

이태봉,이춘주,Lee, Tae-Bong,Lee, Choon-Joo 한국국방경영분석학회 2010 한국국방경영분석학회지 Vol.36 No.1

This paper tries to identify emerging defense technology using S&T Text Mining. As a national agenda, there has been much effort to build S&T information systems including NTIS and DTiMS that enable researchers, policy makers, or field users to analyze technological changes and promote the best policy practices for efficient workflow, knowledge sharing, strategy development, or institutional competitiveness. In this paper, the S&T Text Mining application to unmanned combat technology using INSPEC DB is empirically illustrated and shows that it is a feasible approach to identify emerging defense technology as well as the structure of knowledge network of the future technology candidates. 본 연구에서는 과학기술 텍스트 마이닝을 이용하여 국방 유망기술을 식별하는 방법론을 제안하고 있다. 그동안 국가차원에서 NTIS와 DTiMS를 포함한 과학기술 관련 정보체계를 구축하는데 많은 노력을 기울여왔는데 과학기술 정보체계는 연구자와 정책입안자, 또는 실무자들이 기술적 변화를 분석하고 효율적인 업무진행, 지식공유, 전략개발, 또는 조직의 경쟁력을 높이기 위한 정책개발에 활용성이 크다. 본 연구에서는 INSPEC 데이터베이스에 과학기술 텍스트마이닝 기법을 적용하여 미래 무인전투기술에 대한 지식네트워크 구조와 국방 유망기술을 식별하는 과정을 예시함으로써 구축된 과학기술 정보체계를 이용한 미래 유망기술의 식별 방법론을 제시하였다.

엔탈피 모델을 이용한 레이저 용융풀 형상에 대한 수치해석연구

이태봉(T. LEE),정하승(H. Cheung),신승원(S. Shin) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.4

Laser welding is widely used in the industry for the advantage of small heat affected zone and short weld process time. Conduction limit welding can be used to modify the surface characteristic and it is important to identify the heat affecting area correctly for the improvement of manufacturing accuracy. Since time and length scale associated with laser welding process are extremely small, numerical study can be a useful tool. In this study, two-dimensional axi-symmetric version of energy equation with enthalpy method has been used to analyze the effect of laser input conditions on final shape by the laser welding process. The proposed numerical procedure has been benchmarked with several experimental results and compared well. The modified Marangoni and Peclet number have been introduced using controllable input variables. Simple parametric researches have been performed for high Prnumber material. The results show that higher Marangoni number increase fluid mixing, thus generating convex type weld pool. On the other hand, the width of the weld pool is proportional to Peclet number.

대용량 직류버스 커패시터의 고장진단을 위한 외란특성 반영의 레퍼런스 모델 개선

이태봉(Tae-Bong Lee) 대한전기학회 2017 전기학회논문지 P Vol.66 No.4

The DC electrolytic capacitor for DC-link of power converter is widely used in various power electronic circuits and system application. Its functions include, DC Bus voltage stabilization, conduction of ripple current due to switching events, voltage smoothing, etc. Unfortunately, DC electrolytic capacitors are some of the weakest components in power electronics converters. Many papers have proposed different algorithms or diagnosis method to determinate the ESR and tanδ capacitance C for fault alarm system of the electrolytic capacitor. However, both ESR vary with frequency and temperature. Accurate knowledge of both parameters at the capacitors operating conditions is essential to achieve the best reference data of fault alarm. According to parameter analysis, the capacitance increases with temperature and the initial ESR decreases. Higher frequencies make the reference ESR with the initial ESRo value to decrease. Analysis results show that the proposed DC Bus electrolytic capacitor reference ESR model setting technique can be applied to advanced reference signal of capacitor diagnosis systems successfully.

비선형 마찰력이 있는 시스템의 강인한 적응제어기법

이태봉(Lee, Tae-Bong),양현석(Yang, Hyun-Suk),김병한(Kim, Byung-Han) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.11

본 논문에서는 부분적으로 알고 있는 비선형 마찰력이 있는 2차 기계시스템에 대한 강인한 적응제어 기법을 제시한다. 제시하는 적응제어 방법은 잡음이나 모델링 에러가 없는 경우에는 위치 및 속도 추적 오차는 점근적으로 영으로 수렴함을 보장하며, 잡음이나 모델링 에러가 있는 경우에는 그동안 발표된 다른 논문의 결과와 달리 디자인 변수를 적절하게 선택하면 위치 및 속도 추적 오차를 원하는 범위까지 줄일 수 있음을 보였으며 이는 시뮬레이션 결과를 통해 입증하였다. In this paper, an adaptive nonlinear friction compensation scheme for second-order nonlinear mechanical system with a partially known nonlinear dynamic friction is proposed to achieve asymptotic position and velocity tracking in the absence of disturbances and modeling errors. It is also shown that even with disturbances and modeling errors, in contrast to existing other adaptive control schemes, by proper adjustment of design parameters, reduced error bounds on position and velocity tracking can be achieved.

고유구조 지정에 의한 슬라이딩 평면 설계와 불확실한 시스템의 슬라이딩 모드 제어

이태봉(Tae Bong Lee),양현석(Hyun Suk Yang) 제어로봇시스템학회 2009 제어·로봇·시스템학회 논문지 Vol.15 No.8

In this paper, a new method to design sliding surfaces using eigenstructure assignment is proposed. Most conventional methods for constructing the surfaces require special form like canonical or regular canonical form of system matrices. But the proposed method can be applied to arbitrary system matrices. Futhermore, the surface matrix, C can be decided for the matrix multiplication, CB to have a designated form. SVD is used to decide desirable eigenvectors explicitly. To verify the proposed algorithm, a sliding mode controller for a multi variable system with matched uncertainty is constructed. The controller is designed to guarantee minimum approach velocity to the sliding surface.

브랜드를 통한 미래적 한국언어의 한계점 극복에 관한 연구

이태봉(Lee Tae-Bong),정성환(Chung Sung-Whan) 한국디자인학회 2004 한국디자인학회 학술발표대회 논문집 Vol.- No.-

최대 반복 횟수 없이 튜닝에 기반을 둔 HS 최적화 구현

이태봉(Tae-bong Lee) 대한전기학회 2018 전기학회논문지 P Vol.67 No.3

Harmony search (HS) is a relatively recently developed meta-heuristic optimization method imitating the music improvisation process where musicians improvise their instruments’ pitches searching for a perfect state of harmony. In the conventional HS algorithm, it is necessary to determine the maximum number of iterations with some algorithm parameters. However, there is no criterion for determining the number of iterations, which is a very difficult problem. To solve this problem, a new method is proposed to perform the algorithm without setting the maximum number of iterations in this paper. The new method allows the algorithm to be performed until the desired tuning is achieved. To do this, a new variable bandwidth is introduced. In addition, the types and probability of harmonies composed of variables is analyzed to help to decide the value of HMCR. The performance of the proposed method is investigated and compared with classical HS. The experiments conducted show that the new method generally outperformed conventional HS when applied to seven benchmark problems.

HS 최적화 알고리즘 성능 향상에 관한 연구

이태봉 ( Tae-bong Lee ) 한국항행학회 2021 韓國航行學會論文誌 Vol.25 No.5

Harmony Search(HS) 알고리즘은 음악 즉흥 연주 프로세스에서 영감을 받은 메타 휴리스틱 최적화 알고리즘으로 다양한 최적화 문제를 해결하는 데 성공적으로 적용되어 왔다. 본 논문에서는 HS의 성능을 더욱 향상시키기 위해 FSH(Fast Harmony Search) 알고리즘을 제안하였다. 이를 위해 본 논문에서는 HM을 이용하여 목적 변수의 경곗값을 새롭게 정의하여 독립적인 두 개의 화음 개선과정을 하나로 통합하는 방법을 제안하였다. 그 결과 알고리즘의 처리 시간이 단축되고 대역폭의 명시적인 결정이 더이상 필요하지 않게 되었다. 또한, 무작위 선택의 활용능력이 향상되었다. 수치적 예시 결과는 제안된 알고리즘이 기존의 HS에 비해 더 나은 해를 찾을 수 있으며 속도 또한 빠르다는 것을 보여준다. Harmony Search(HS) algorithm is an emerging meta-heuristic optimization algorithm, which is inspired by the music improvisation process and has been successfully applied to solve different optimization problems. In order to further improve the performance of HS, this paper proposes a new method which is called Fast Harmony Search(FSH) algorithm. For the purpose, this paper suggest a method to unify two independent improvisation processes by newly defining the boundary value of a object variable using HM. As the result, the process time of the algorithm is shorten and explicit decision of bandwidth is no more needed. Furthermore, exploitative power of random selection is improved. The numerical results reveal that the proposed algorithm can find better solutions and is faster when compared to the conventional HS.

HS 최적화 알고리즘을 이용한 전력용 변압기의 경제적 수명평가

이태봉(Tae-bong Lee),손진근(Jin-geun Shon) 대한전기학회 2017 전기학회논문지 P Vol.66 No.3

Electric utilities has been considered the necessity to introduce AM(asset management) of electric power facilities in order to reduce maintenance cost of existing facilities and to maximize profit. In order to make decisions in terms of repairs and replacements for power transformers, not only measuring by counting parts and labor costs, but comprehensive comparison including reliability and cost is needed. Therefore, this study is modeling input cost for power transformer during its entire life and also the life cycle cost (LCC) technique is applied. In particular, this paper presents an application of heuristic harmony search(HS) optimization algorithm to the convergence and the validity of economic life assessment of power transformer from LCC technique. This recently developed HS algorithm is conceptualized using the musical process of searching for a perfect state of harmony. It uses a stochastic random search instead of a gradient search so that derivative information is unnecessary. The effectiveness of the proposed identification method has been demonstrated through an economic life assessment simulation of power transformer using HS optimization algorithm.

HS 최적화 하모니 개선을 위한 새로운 전략

이태봉 ( Lee¸ Tae Bong ) 한국경영공학회 2020 한국경영공학회지 Vol.25 No.4

Purpose The purpose of this paper is to improve the performance of HS meta-heuristic optimization algorithm. Methods Based on the two problems consciousness against the conventional harmony improvisation process, a new pitch adjustment referring to the best harmony is introduced and developed. For the test, the proposed strategy is applied to the optimization test functions. Results The propose method is applied to several simple and complex optimization test function. The results shows that the proposed strategy surpasses the performance of conventional method. Conclusion The new strategy works very well and algorithm parameters tunning is needed to improve further the performance of the new method.