• Earthquakes and Structures
• /
• 제12권3호
• /
• pp.285-296
• /
• 2017

Base isolation is a quite practical control strategy for enhancing the response of structural systems induced by strong ground motions. Due to the dynamic effects of base isolation systems, reduction in the interstory drifts of the superstructure is often achieved at the expense of high base displacement level, which may lead to instability of the structure or non-practical designs for the base isolators. To reduce the base displacement, several hybrid structural control strategies have been studied over the past decades. This study investigates a particular strategy that employs Tuned Mass Dampers (TMDs) for improving the performance of base-isolated structures and unlike previous studies, specifically focuses on the effectiveness of this hybrid control strategy in structures that are equipped with nonlinear base isolation systems. To consider the nonlinearities of base isolation systems, a Bouc-Wen model is selected and nonlinear dynamic OpenSees models are used to perform several time-history simulations in time and frequency domains. Through these numerical simulations, the effects of several parameters such as the fundamental period of the structure, dynamic properties of the TMD and isolation systems and properties of the input ground motion on the behaviour of TMD-structure-base isolation systems are examined. The results of this study provide a better insight into the performance of linear shear-story structures with nonlinear base isolators and show that there are many scenarios in which TMDs can still improve the performance of these systems.

• 한국직업건강간호학회지
• /
• 제27권1호
• /
• pp.48-58
• /
• 2018

Purpose: The purpose of this study was to understand the present status of the work performance of the construction industry health managers and the developmental direction for the construction industry health management. Methods: The subjects of this study were 149 health managers working in the construction industry. Data of a total of 130 participants were analyzed by excluding the missing data among field workers. The contents of the survey were the characteristics of the workplace, the difficulties and requirements of health management, and the level of job performance. Results: The factors affecting measuring work environment task were age, number of workers, number of safety managers, and lack of support from the headquarters. The factors affecting managing work environment and physicochemical harmful factors were age, type of contract and conflicting business opinions. The factors affecting implementing health examination were age, type of contract, and number of safety managers. The factors affecting healthcare were age, type of contract, number of safety manager, presence of healthcare room, and conflicting business opinions. Conclusion: It is necessary to provide practical guidance and practical resources, and education for strengthening capacity. The support for business owners and managers support is needed.

• 기술혁신연구
• /
• 제21권1호
• /
• pp.229-252
• /
• 2013

본 연구의 목적은 연구개발(R&D) 프로젝트의 성과를 재무적 가치로 측정하기 위한 모델을 제안하는 것이다. 이를 위해 선행 연구를 통해 연구개발 프로젝트 성과를 측정할 수 있는 지표를 추출하고, 그 측정 방법을 제시하였다. R&D 성과를 재무적 가치로 환산하려는 일부 시도가 있었으나 전문가 평가, 예상 매출액, 미래시장 점유율, 할인율, 순현재가치, 실물옵션 접근법 등 주관적 의견과 과도한 예측으로 측정결과에 대한 의문이 제기되었다. 이러한 문제점을 보완하고 다양한 각도에서 재무적 가치로 평가가 가능한 모델을 제안하고자 한다. 개발된 모델을 국내 IT 기업의 실제 사례를 통하여 검증을 실시하여 신뢰성을 높였기 때문에 추후 기업의 R&D 프로젝트에 대한 경제적 평가에 새로운 전기를 마련할 수 있을 것으로 기대된다.

• 한국음향학회지
• /
• 제20권6호
• /
• pp.26-33
• /
• 2001

기존의 AR HMM(auroreg ressive hidden morkov model)에 의한 화자인식 방법은 그 성능이 우수하나, 잡음에 대한 것이 고려되지 않아 실제 환경에 적용시 성능저하가 문제가 된다. 본 논문에서는 실제 환경에 맞추기 위하여 관측 신호 모델에서 잡음을 고려하고, 화자인식 성능을 개선하고자 지속시간항 (duration-term)을 포함하는 AR HMM을 이용하여 잡음환경에서의 강인한 화자인식 시스템을 제안한다. 100명의 화자 (남자 77명, 여자 23명)가 2주에 걸쳐 6번 발성한 숫자음 데이터베이스을 가지고, 백색잡음 및 자동차 잡음하에서 실험한 결과, 제안된 방법으로 성능이 향상됨을 확인하였다.

• Human Ecology Research
• /
• 제53권1호
• /
• pp.81-92
• /
• 2015

Daily dance Ganggangsullae is recommended for youth to help their diet, improve their team life and know Korean culture. Its performance costumes were fusion hanbok and casual wear shown at the Second Daily Dance Ganggangsullae Contest Conference of Myeongryang Battle Festival in 2013. A fusion hanbok shows the Korean traditional spirit, but it is not practical. Casual wear is practical, but it does not show any Korean identity. Therefore, their combination is needed to reflect the Korean identity and practicality. For this, a literature review and an online search were conducted for the history, purpose and dance motion of daily dance Ganggangsullae. And photographs of participating teams were gathered from Jeonnam Information & Culture Industry Promotion Agency. Goguryeo costumes were used for design motifs. Four designs were sets of T-shirts and pants for the summer. Style 1 is designed using sam, jikryeong, go, round and triangle pattern with rippled cotton. Colors were from Wang Huiji's mural painting. Style 2 is designed using dansuui, beonryeong, go, round and quadrangle patterns with rippled cotton. Colors were from a Deokheungri mural painting. Style 3 is designed using sam, round ryeong, go, quadrangle patterns, prints with cotton jersey and denim. Colors were from a Gamsinchong mural painting. Style 4 is designed using dansuui, jikryeong, go, a flame pattern, a bow and arrow shape with cotton, knit and jersey. Colors were from a Muyongchong mural painting. This study is helpful to anyone who wants to develop Korean-style performance costumes.

• International Journal of Control, Automation, and Systems
• /
• 제6권2호
• /
• pp.204-213
• /
• 2008

In this paper, we present the practical application of an Unscented Kalman Filter (UKF) for an Indoor Mobile Localization System using ultrasonic sensors. It is true that many kinds of localization techniques have been researched for several years in order to contribute to the realization of a ubiquitous system; particularly, such a ubiquitous system needs a high degree of accuracy to be practical and efficient. Unfortunately, a number of localization systems for indoor space do not have sufficient accuracy to establish any special task such as precise position control of a moving target even though they require comparatively high developmental cost. Therefore, we developed an Indoor Mobile Localization System having high localization performance; specifically, the Unscented Kalman Filter is applied for improving the localization accuracy. In addition, we also present the additive filter named 'Pre-filtering' to compensate the performance of the estimation algorithm. Pre-filtering has been developed to overcome negative effects from unexpected external noise so that localization through the Unscented Kalman Filter has come to be stable. Moreover, we tried to demonstrate the performance comparison of the Unscented Kalman Filter and another estimation algorithm, such as the Unscented Particle Filter (UPF), through simulation for our system.

• 전기학회논문지
• /
• 제60권2호
• /
• pp.407-415
• /
• 2011

In this study, we propose the design of optimized fuzzy controller for the rotary inverted pendulum system by using differential evolution algorithm. The structure of the differential evolution algorithm has a simple structure and its convergence to optimal values is superb in comparison to other optimization algorithms. Also the differential evolution algorithm is easier to use because it have simpler mathematical operators and have much less computational time when compared with other optimization algorithms. The rotary inverted pendulum system is nonlinear and has a unstable motion. The objective is to control the position of the rotating arm and to make the pendulum to maintain the unstable equilibrium point at vertical position. The output performance of the proposed fuzzy controller is considered from the viewpoint of performance criteria such as overshoot, steady-state error, and settling time through simulation and practical experiment. From the result of both simulation and practical experiment, we evaluate and analyze the performance of the proposed optimal fuzzy controller from the comparison between PGAs and differential evolution algorithms. Also we show the superiority of the output performance as well as the characteristic of differential evolution algorithm.

• Wind and Structures
• /
• 제38권5호
• /
• pp.399-410
• /
• 2024

Long-span suspension bridges located in typhoon-prone regions face significant risks of flutter instability, particularly in girder erection. Despite the implementation of aerodynamic countermeasures designed for the service stage, the flutter stability of bridge in girder erection may not meet the required standards. Nowadays, the double-deck truss girder is increasingly common in practical engineering which exhibits different performance from the single-deck truss girder. To gain insights into the flutter performance of this girder type and determine temporary aerodynamic countermeasures for flutter suppression in girder erection, wind tunnel tests were conducted. The effects of affiliated members on the flutter performance were first examined. Subsequently, different aerodynamic countermeasures were designed and their effectiveness was tested. The results indicate that the stabilizers above and below the upper and lower decks are the most effective for the flutter stability of bridge at positive and negative angles of attack, respectively. The higher the stabilizers are, the better the effect on flutter suppression achieves. Considering the feasibility in practical engineering, a temporary stabilizer above the upper deck was considered. It is expected that the results could provide references for the aerodynamic design of double-deck truss girder during erection.

• 음성과학
• /
• 제9권3호
• /
• pp.25-34
• /
• 2002

One of the most important factor in the performance of Korean text-to-speech system is the prediction of accentual and intonational phrase boundary. The previous method of prediction shows only the 75-85% which is not proper in the practical and commercial system. Therefore, more accurate prediction must be needed in the practical system. In this study, we propose the simple and more accurate method of the prediction of AP, IP.

• 한국동물번식학회:학술대회논문집
• /
• 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
• /
• pp.8-8
• /
• 2002

Goats have long history in Korea. But because of small holding, is there no systematic development for breeding and reproduction. The most of goats in Korea have some typical problems, which gradually appeared through inbreeding. The purpose of this study was to evaluate effects of hormonal treatment on estrus synchronisation in non-breeding seasons and to estimate economical aspects of caprine embryo transfer. Otherwise we would like to develop a suitable practical method of field embryo transfer, in order to obtain the more basical breeding materials for high-performance goat. (omitted)