건축구조물의 내진보강을 위한 회전형 마찰감쇠기의 성능실험

노지은,이상현,Roh, Ji-Eun,Lee, Sang-Hyun 대한건축학회 2011 대한건축학회논문집 Vol.27 No.12

In this study, a new type of rotary friction damper was proposed for the seismic retrofitting of building structures. The rotary friction damper was composed of 2 rotary friction pads, 3 steel plates, and 9-13 bolt holes. The clamping forces can be modulated for realizing the various yield moment of the damper. The test results indicated that the proposed damper showed stable hysteretic behavior and the designed yield moment could be obtained according to the applied torque and the number of bolt holes. Numerical analyses of a moment-frame retrofitted with the proposed dampers should that the seismic performance could be enhanced according to the yield moment of the dampers.

CFAR 적용시 섹션 크기 가변화를 이용한 오표적의 효율적 제거

노지은,최병관,이희영,Roh, Ji-Eun,Choi, Beyung-Gwan,Lee, Hee-Young 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.1

Generally, because received signals from radar are very bulky, the data are divided into manageable size called section, and sections are distributed into several digital signal processors. And then, target detection algorithms are applied simultaneously in each processor. CFAR(Constant False Alarm Rate) algorithm, which is the most popular target detection algorithm, can estimate accurate threshold values to determine which signals are targets or noises within center-cut of section allocated to each processor. However, its estimation precision is diminished in section edge data because of insufficient surrounding data to be referred. Especially this edge problem of CFAR is too serious if we have many sections to be processed, because it causes many false alarms in most every section edges. This paper describes false alarm issues on MCA(Minimum Cell Average)-CFAR, and proposes a false alarm elimination method by changing section size alternatively. Real received data from multi-function radar were used to evaluate a proposed method, and we show that our method drastically decreases false alarms without missing real targets, and improves detection performance.

레이더의 부하 상태에 따른 빔 스케줄링 알고리즘의 선택적 적용

노지은,김동환,김선주,Roh, Ji-Eun,Kim, Dong-Hwan,Kim, Seon-Joo 한국군사과학기술학회 2012 한국군사과학기술학회지 Vol.15 No.3

AESA radar is able to instantaneously and adaptively position and control the beam, and such adaptive beam pointing of AESA radar enables to remarkably improve the multi-mission capability. For this reason, Radar Resource Management(RRM) becomes new challenging issue. RRM is a technique efficiently allocating finite resources, such as energy and time to each task in an optimal and intelligent way. Especially radar beam scheduling is the most critical component for the success of RRM. In this paper, we proposed a rule-based scheduling algorithm and Simulated Annealing(SA) based scheduling algorithm, which are alternatively selected and applied to beam scheduler according radar load status in real-time. The performance of the proposed algorithm was evaluated on the multi-function radar scenario. As a result, we showed that our proposed algorithm can process a lot of beams at the right time with real time capability, compared with applying only rule-based scheduling algorithm. Additionally, we showed that the proposed algorithm can save scheduling time remarkably, compared with applying only SA-based scheduling algorithm.

경주지진과 유사한 특성을 가지는 지반가속도로 가진된 단주기 구조물 변위연성도 평가

노지은,이상현,서준원,김동관,Roh, Ji Eun,Lee, Sang Hyun,Seo, Jun Won,Kim, Dong Kwan 한국지진공학회 2016 한국지진공학회논문집 Vol.20 No.7

In this paper, time and frequency domain characteristics of Gyeong-ju earthquakes were investigated, and nonlinear time history analyses were conducted for bi-linear hysteretic structures excited by short-duration ground accelerations. Previous studies showed that larger inelastic displacements than the peak displacement of the corresponding elastic system were observed especially for the structures with structural period shorter than 0.3s, and the similar results could be obtained when long-duration ground accelerations were used as excitation loads. For the short-duration earthquakes, however, the inelastic displacements were not so large and almost identical to the peak elastic displacements.

구문 정보와 비용기반 중심화 이론에 기반한 자연스러운 지시어 생성

노지은(Ji-Eun Roh),이종혁(Jong-Hyeok Lee) 한국정보과학회 2004 정보과학회논문지 : 소프트웨어 및 응용 Vol.31 No.12

텍스트 생성(text generation)은 언어가 아닌 다양한 지식원으로부터 텍스트를 생성해 내는 언어 처리의 한 분야로, 여러 가지 복합적이고 단계적인 과정을 통해 이루어진다. 본 논문에서는 자연스러운 텍스트 생성을 위한 여러 과정 중, 한번 언급된 대상(entity)을 자연스럽게 지시(refer)하기 위한 지시어생성(referring expression generation), 특히 한국어에 두드러진 영형(zero pronoun)에 의한 대용화(pronominalization) 과정에 초점을 맞춘다. 이를 위해, 구문 정보와 비용기반 중심화 이론(cost-based centering model)을 바탕으로, 한국어에 적합한 지시어 특히 영형의 생성에 영향을 미치는 다양한 자질(feature)들을 규명하고, 기계 학습을 통해 지시어 생성 모델을 구축하였다. 세 개의 장르 - 묘사문(설명문), 뉴스, 짧은 우화 - 에서 총 95개의 텍스트로부터 학습이 이루어 졌으며 이를 대상으로, 제안된 자질들이 지시어의 생성, 특히 영형의 생성에 효율적으로 적용될 수 있음을 보였다. 또한, 지시어 생성과 관련된 기존의 방법론들과 본 논문에서 제안한 모델을 비교하여 성능이 크게 향상되었음을 보이고, T-test를 통해 99.9%의 신뢰 구간에서 그 성능 향상이 통계적으로 의미가 있음을 확인하였다. Text Generation is a process of generating comprehensible texts in human languages from some underlying non-linguistic representation of information. Among several sub-processes for text generation to generate coherent texts, this paper concerns referring expression generation which produces different types of expressions to refer to previously-mentioned things in a discourse. Specifically, we focus on pronominalization by zero pronouns which frequently occur in Korean. To build a generation model of referring expressions for Korean, several features are identified based on grammatical information and cost-based centering model, which are applied to various machinelearning techniques. We demonstrate that our proposed features are well defined to explain pronominalization, especially pronominalization by zero pronouns in Korean, through 95 texts from three genres - Descriptive texts, News, and Short Aesop's Fables. We also show that our model significantly outperforms previous ones with a 99.9% confidence level by a T-test.

홈쇼핑 사이트를 위한 데이터베이스로부터의 한국어 텍스트 생성

노지은(Ji-Eun Roh),강신재(Sin-Jae Kang),이종혁(Jong-Hyeok Lee) 한국정보과학회 2001 한국정보과학회 학술발표논문집 Vol.28 No.1B

국내에서는 한국어 생성에 있어서 기계 번역에 기반한 자연스러운 한국어 문장(sentence)의 생성에 관한 연구가 주로 이루어졌었다. 반면에 다양한 지식원으로부터 여러 문장이 긴밀히 결합되어 하나의 텍스트를 생성하는 텍스트 생성에 관한 연구는 거의 이루어지지 않았었다. 문장 단위의 기계 번역에서의 한국어 생성과는 또 다른 다양한 논점을 가지고 있는 텍스트 생성에 관해, 본 논문에서는 데이터베이스를 지식원으로 하여 하나의 일관된 정보를 전달하는 단락 단위의 자연스러운 한국어 텍스트를 생성하는 시스템을 제안한다.

중심화 이론을 이용한 텍스트 구조화

노지은(Ji-Eun Roh),나승훈(Seung-Hoon Na),이종혁(Jong-Hyeok Lee) 한국정보과학회 2007 정보과학회논문지 : 소프트웨어 및 응용 Vol.34 No.6

본 논문에서는 자연스러운 텍스트 생성을 위한 여러 과정 중, 문장 순서를 결정하기 위한 텍스트 구조화(text structuring)에 관한 것으로, 중심화 이론(centering theory)에 기반하여 문장 순서의 자연스러움을 판단할 수 있는 다양한 평가 척도를 논의한다. 먼저, 기존 연구들에서 중심화 이론에 기반한 문장 순서의 평가 척도들 중 가장 효과적이라고 알려진 MIN.NOCB를 텍스트 구조화에 적용할 때 발생할 수 있는 문제점을 지적하고, 대안이 될 수 있는 새로운 평가 척도인 MAX.CPS를 제안한다. 또, 임의의 평가 척도가 주어진 문장들에 대해 가질 수 있는 기대치를 먼저 예측하고, 그것에 따라 다른 평가 척도를 적용하게 하는 프레임워크를 제안하여, 중심화 이론 안에서 최상의 문장 순서를 찾기 위한 새로운 방법론을 모색한다. 또한, 중심화 이론의 적용에 있어 핵심이라 할 수 있는, 명사들의 돋보임성(salience)을 서열화(cf-ranking) 하는 다양한 방식을 중심화 기반 문장 순서 평가 척도의 관점에서 분석하였다. 그 결과, 텍스트 구조화에 관한 한, 단순히 문장에서 실현된 순서에 따라 명사들의 돋보임성의 서열을 정하는 것이 한국어의 특성상 가장 간단하면서도 효율적임을 입증하였다. This paper investigates Centering-based metrics to evaluate ordering of utterances for text structuring. We point out a problem of MIN.NOCB metric which has been regarded as the simplest and best measure to evaluate coherence of ordering within Centering framework, and propose a new Centering-based metric, MAX.CPS as an alternative or supplementary one. This paper introduces a framework which pre-estimates the effectiveness of a metric on a given input ordering, and selects an applicable metric according to the pre-estimation result. Using this framework, we propose a new policy which can generate more optimal ordering within Centering framework. Moreover, we evaluate several kinds of Cf-ranking methods in terms of Centering-based metrics, and find that simply ranking entities by their linear order is generally the most suitable because of characteristics in Korean.

반복하중을 받는 수동형 다중거동 복합 감쇠장치의 실험적 구조성능 평가

노지은(Roh, Ji-Eun),이상현(Lee, Sang-Hyun) 대한건축학회 2016 大韓建築學會論文集 : 構造系 Vol.32 No.11

In this study, a multi-action hybrid damper (MHD) showing independent hysteretic characteristics for small and large loading conditions is presented. The MHD is composed of steel elements, two friction pads, and two lead-rubber bearings. Since the friction pads and the lead-rubber bearings are in series connection, only the lead rubber bearing deforms according to the excitation loads before the friction pad slippage occurs, and after the friction slippage, anymore deformation of the lead-rubber bearing does not occur and energy dissipation and damper deformation concentrates on the friction pad. Initial stiffness and hysteresis for small load such as wind for low-rise building is governed by the lead rubber bearing and yielding or friction load for the larger load such as earthquake is determined by the friction pad. Accordingly, the load-deformation behaviors before/after the friction slippage can be independently designed to show good performance for a building structure subject to wind and earthquake loads. The multi-action behavior and energy dissipation capacity of the MHD were evaluated by conducting the cyclic loading tests using a full scale MHD. The test results indicate that the MHD shows the expected hysteretic behavior and stable energy dissipation performance.

건축구조물의 내진보강을 위한 회전형 마찰감쇠기의 성능실험

노지은(Roh, Ji-Eun),이상현(Lee, Sang-Hyun) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.12

In this study, a new type of rotary friction damper was proposed for the seismic retrofitting of building structures. The rotary friction damper was composed of 2 rotary friction pads, 3 steel plates, and 9-13 bolt holes. The clamping forces can be modulated for realizing the various yield moment of the damper. The test results indicated that the proposed damper showed stable hysteretic behavior and the designed yield moment could be obtained according to the applied torque and the number of bolt holes. Numerical analyses of a moment-frame retrofitted with the proposed dampers should that the seismic performance could be enhanced according to the yield moment of the dampers.

능동제어 알고리즘에 따른 AMD의 제어성능 평가

노지은(Roh, Ji Eun),이상현(Lee, Sang Hyun),정란(Chung, Lan) 한국콘크리트학회 2013 한국콘크리트학회 학술대회 논문집 Vol.2013 No.5