• 한국소음진동공학회논문집
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• 제16권2호
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• pp.207-213
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• 2006

In our previous research, we proposed a robust saturation controller which involves both control input saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Expecially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.

• 자원환경지질
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• 제30권3호
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• pp.241-248
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• 1997

In this study, Ichon basin is selected as study area and regional analysis of geological structure are done by using lineament analysis. The factors which affects slope stability, are chosen, and integrated to database using GIS (Geoscientific Information System). Landsat TM band 4, 5 and 7 are choosen and processed by various image enhancement technique to analyse the regional geological lineaments. Spatial distribution of lineament is analysed through lineament density map and study area can be divided the eight structural domains. Considering environmental geological characteristics of study area, rating and weighting of each factors for slope stability analysis are determined and spatial analysis of regional slope stability is examined through overlaying technique of GIS. The result of areal distribution of slope stability shows that the most unstable area is all over Mt. Buksung, Mt. Daepo, Mt. Songrim and Mt. Yankak.

• 한국가구학회지
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• 제13권1호
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• pp.2-8
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• 2002

This study was carried out to investigate the reasonable condition for better dimensional stability in woods by polyethylene glycol(PEG) treatment. Eight species grown in Kangwon-do were used for this study. Three species of softwoods(Pinus densiflora, Pinus koraiensis, Larix kaempferi) and two species of hardwoods(Prunus sargentii, Populus tomentiglandulosa) treated with 30% aqueous solution of PEG 1000 showed good dimensional stability under the treatment for 1 day. The dimensional stability of Betula davurica, Quercus mongolica and Quercus variabilis woods increased with increasing treatment time. From the above results, it was concluded that PEG penetration and dimensional stability were affected by characteristics of wood species such as density and structure.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.265-270
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• 1998

In this paper we introduce a modeling of wheeled mobile robot with a differential drive derived by R.M. DeSantis and using the dynamics model-ing with some disturbance term we control the wheeled mobile robot using fuzzy sliding mode control(FSMC) method. In a fuzzy control approach it is very difficult to prove the stability of the fuzzy controller. Therefore, to overcome that difficult proof of the stability in a fuzzy control method, we first propose a sliding mode controller and prove the stability of the proposed controller. Next, transforming the proposed sliding mode controller into a fuzzy sliding mode controller without changing the basic structure of the sliding mode con-troller, we easily obtain a fuzzy sliding mode con-troller(FSMC) whose stability is guaranteed with-out difficult stability proof procedure of the proposed FSMC.

• Journal of Power Electronics
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• 제9권1호
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• pp.61-67
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• 2009

In this paper, a simple technique is presented for robust stability testing of perturbed DC-DC converters having multi-linear uncertainty structure. This technique provides a necessary and sufficient condition for testing robust stability. It is based on the corollary of Routh criterion and gridding of parameters. The previous work based on parametric control theory using Kharitonov's theorem and Hermite Biehler theorem gives conservative results and only the sufficient condition of stability, whereas the proposed method provides the necessary and sufficient condition for testing robust stability and it is computationally efficient. The superiority of the method is compared with the Edge theorem.

• 대한수학회보
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• 제52권4호
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• pp.1069-1076
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• 2015

In this paper, a two species competitive model with stage structure and harvesting is investigated. By using the differential inequality theory, some new sufficient conditions which ensure the permanence of the system are established. Our result supplements the main results of Song and Chen [Global asymptotic stability of a two species competitive system with stage structure and harvesting, Commun. Nonlinear Sci. Numer. Simul. 19 (2001), 81-87].

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.643-647
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• 1990

Gunner primary sight(GPS) stabilization system lays line of sight(LOS) to find out a target and transmits informations to the fire control system (FCS). In a moving vehicle, accuracy of LOS and FCS depends on the design of GPS and servomechanism system. The heavy vibration of vehicle on the severe off-road environment degenerates the stabilization capability of GPS. In this study, to stabilize of elevation for GPS using the variable structure control, we derived the dynamic equation of GPS system and designed the variable structure controller. Computer simulation results fulfilled the static and dynamic stability of GPS using the variable structure control.

• Steel and Composite Structures
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• 제24권3호
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• pp.287-296
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• 2017

The buckling capacity of a radially retractable hybrid grid shell in the closed position was investigated in this paper. The geometrically non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. A parametric study was done to investigate the effects rise-to-span ratio, beam section, area and pre-stress of cables, on the failure load. Also, the influence of the shape and scale of imperfections on the elasto-plastic buckling loads was discussed. The results show that the critical buckling load is reduced by taking account of material non-linearity. Furthermore, increasing the rise-to-span ratio or the cross-section area of steel beams notably improves the stability of the structure. However, the cross section area and pre-stress of cables pose negligible effect on the structural stability. It can also be found that the hybrid structure is highly sensitive to geometric imperfection which will considerably reduce the failure load. The proper shape and scale of the imperfection are also important.

• KIEAE Journal
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• 제9권2호
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• pp.43-52
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• 2009

The aim of this study is to find out the solutions for an improvement of residential environment through the relation between satisfaction of residential environment and amenity awareness of the local residents in Chonnam Mokpo city. For this purpose, it is conducted a questionnaire survey of 203 local residents on the attributes of residential environment. The satisfaction factors of residential environment consist of 8 types of factors such as housing structure, stability, green tract of an avenue, convenience, housing environment, sanitary conditions, waterside facilities, and familiarity. It is analyzed that there is a great difference of the satisfaction between new town dwellers and old town dwellers in three satisfaction factors of a housing structure, convenience, and housing environment. The attributes of amenity awareness consist of 6 types of factors such as fitness, comfort, intimacy, vitality, naturalness, and brilliance. The new town dwellers have a high satisfaction in fitness and vitality factors, and the old town dwellers have a high satisfaction in naturalness factors. Through the analysis to the importance on the satisfaction factors of residential environment related to amenity awareness, it is founded that intimacy factor have importance in order of stability, familiarity, green tract of an avenue and sanitary conditions. Naturalness factor have importance in order of stability, waterside facilities, familiarity and green tract of a avenue. Fitness factor have importance in order of housing structure and sanitary conditions. Comfort factor have importance in order of stability, housing environment and sanitary conditions. And vitality factor have importance in order of housing environment, convenience and green tract of an avenue. Therefore, it is needed that the development plan of residential environment take into consideration in accordance with the importance on the satisfaction of residential environment in Mokpo city.

• 한국산림과학회지
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• 제95권1호
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• pp.5-11
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• 2006

이 연구는 김해시 상동면 매리 산사태지의 발생특성을 밝히기 위한 일련의 연구로 본보에서는 구조물의 안정해석을 실시하였다. 옹벽 및 석축의 외적 안정성 검토 결과, II-D단면을 제외하고는 모두 불안정한 것으로 산정되어 구조물에 대한 안정 대책이 필요한 것으로 판단되었다. 또한, 불안정한 옹벽은 보강하고 여기에 배수공을 추가로 설치하여 안정을 도모할 필요가 있을 것으로 사료된다. 아울러 이 지역의 석축 구조물은 사면활동에 저항하기 위하여 석축 상부의 사면을 완화하여 상부로부터의 하중을 감소시키는 방법이 유용할 것으로 생각된다.