• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2033-2038
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• 2003

This paper describes an integrated navigation strategy for the autonomous service robot PSR. The PSR is under development at the KIST for service tasks in indoor public environments. The PSR is a multi-functional mobile-manipulator typed agent, which works in daily life. Major advantages of proposed navigation are as follows: 1) Structured control architecture for a systematic integration of various software modules. A Petri net based configuration design enables stable control flow of a robot. 2) A range sensor based generalized scheme of navigation. Any range sensor can be selectively applied using the proposed navigation scheme. 3) No need for modification of environments. (No use of artificial landmarks.) 4) Hybrid approaches combining reactive behavior as well as deliberative planner, and local grid maps as well as global topological maps. A presented experimental result shows that the proposed navigation scheme is useful for mobile service robot in practical applications.

• 한국산학기술학회논문지
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• 제10권2호
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• pp.320-326
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• 2009

자동차 운전에 있어 운전자의 시야확보는 안전운행을 위한 가장 중요한 요소 중에 하나이다. 따라서 빠른 시간 안에 자동차 전후방에서 펼쳐지는 상황을 파악하는 일이 안전운전의 첫걸음이다. 특히, 사고 발생률 대비 치사율이 가장 높은 안개가 자주 발생하는 지역에서의 시야확보는 필수적이다. 본 논문에서는 GPS를 이용하여 차량내부에 설치되어 있는 임베디드 보드 네비게이션 모니터링 시스템을 통해 다른 차량의 위치를 실시간으로 보여줌으로써 운전자의 시야확보를 제공한다. 본 시스템을 이용하여 안전운행을 할 수 있고 갑자기 일어나는 돌발 상황에 대처하여 추돌사고의 확률을 낮출 수 있다.

• Computers and Concrete
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• 제7권4호
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• pp.365-386
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• 2010

This paper presents the physical formulation of a 1D material model suitable for seismic applications. It is written within the framework of thermodynamics with internal variables that is, especially, very efficient for the phenomenological representation of material behaviors at macroscale: those of the representative elementary volume. The model can reproduce the main characteristics observed for concrete, that is nonsymetric loading rate-dependent (viscoelasticity) behavior with appearance of permanent deformations and local hysteresis (continuum plasticity), stiffness degradation (continuum damage), cracking due to displacement localization (discrete plasticity or damage). The parameters have a clear physical meaning and can thus be easily identified. Although this point is not detailed in the paper, this material model is developed to be implemented in a finite element computer program. Therefore, for the benefit of the robustness of the numerical implementation, (i) linear state equations (no local iteration required) are defined whenever possible and (ii) the conditions in which the presented model can enter the generalized standard materials class - whose elements benefit from good global and local stability properties - are clearly established. To illustrate the capabilities of this model - among them for Earthquake Engineering applications - results of some numerical applications are presented.

• Structural Monitoring and Maintenance
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• 제5권2호
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• pp.273-295
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• 2018

In this study, an investigation of a damage detection methodology for global condition assessment is presented. A particular emphasis is put on the utilization of wireless sensors for more practical, less time consuming, less expensive and safer monitoring and eventually maintenance purposes. Wireless sensors are deployed with a sensor roving technique to maintain a dense sensor field yet requiring fewer sensors. The time series analysis method called ARX models (Auto-Regressive models with eXogeneous input) for different sensor clusters is implemented for the exploration of artificially induced damage and their locations. The performance of the technique is verified by making use of the data sets acquired from a 4-span bridge-type steel structure in a controlled laboratory environment. In that, the free response vibration data of the structure for a specific sensor cluster is measured by both wired and wireless sensors and the acceleration output of each sensor is used as an input to ARX model to estimate the response of the reference channel of that cluster. Using both data types, the ARX based time series analysis method is shown to be effective for damage detection and localization along with the interpretations and conclusions.

• The Journal of the Acoustical Society of Korea
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• 제21권2E호
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• pp.71-80
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• 2002

This paper suggests the Cardioid beamforming algorithm of the doublet sensors employing DIFAR (directional frequency analysis and recording) sensor signals in the frequency domain. The algorithm enables target bearing estimation using the signals from directional sensors. The algorithm verifies its applicability by successfully estimating bearings of a target projecting ten narrow-band signals in shallow water. The estimated bearings agree very well with those from GPS (global positioning system) data. Assuming the bearings from GPS data to be real values, the estimation errors are analyzed statistically. The histogram of estimation errors in each frequency have Gaussian shape, the mean and standard deviation dropping in the ranges -1.1°∼ 6.7°and 13.3∼43.6°, respectively. Estimation errors are caused by SNR (signal to noise ratio) degradation due to propagation loss between the source and receiver, daily fluctuating geo-magnetic fields, and non-stationary background noises. If multiple DIFAR systems are employed, in addition to bearing, range information could be estimated and finally localization or tracking of a target is possible.

• 로봇학회논문지
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• 제7권2호
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• pp.120-128
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• 2012

The loop closure problem is one of the most challenging issues in the vision-based simultaneous localization and mapping community. It requires the robot to recognize a previously visited place from current camera measurements. While the loop closure often relies on visual bag-of-words based on point features in the previous works, however, in this paper we propose a line-based method to solve the loop closure in the corridor environments. We used both the floor line and the anchored vanishing point as the loop closing feature, and a two-step loop closure algorithm was devised to detect a known place and perform the global pose correction. We propose an anchored vanishing point as a novel loop closure feature, as it includes position information and represents the vanishing points in bi-direction. In our system, the accumulated heading error is reduced using an observation of a previously registered anchored vanishing points firstly, and the observation of known floor lines allows for further pose correction. Experimental results show that our method is very efficient in a structured indoor environment as a suitable loop closure solution.

• 한국콘텐츠학회논문지
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• 제16권11호
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• pp.537-548
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• 2016

최근 들어 국내 방송 프로그램 포맷의 중국 시장 진출 규모가 크게 늘고 있다. 특히 중국과의 포맷 거래는 다른 국가와 달리 단순한 포맷 바이블 판매에 그치는 것이 아니라 공동제작 수준으로 제휴 범위가 확대되고 있음에 따라 국내 미디어 시장에 미칠 파장도 클 것으로 예상된다. 따라서 본 연구에서는 지난 7년간 중국에 진출한 국내 예능 프로그램의 포맷 현황을 분석하여 한중 포맷 거래에 있어 그 진출 방식 및 유형은 어떠한지 그 특성을 도출해 보고자 한다. 국내에서 인기를 끈 예능 프로그램 중에서도 어떤 유형이 중국현지에서 시청률이 높은지 살펴보는 작업은 향후 글로벌 시장을 대상으로 한 포맷 개발 및 유통 다각화 전략 수립에도 일조할 수 있을 것으로 여겨진다.

• Journal of Astronomy and Space Sciences
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• 제20권4호
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• pp.359-364
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• 2003

In this paper, we present multi-sensor data fusion for telematics application. Successful telematics can be realized through the integration of navigation and spatial information. The well-determined acquisition of vehicle's position plays a vital role in application service. The development of GPS is used to provide the navigation data, but the performance is limited in areas where poor satellite visibility environment exists. Hence, multi-sensor fusion including IMU (Inertial Measurement Unit), GPS(Global Positioning System), and DMI (Distance Measurement Indicator) is required to provide the vehicle's position to service provider and driver behind the wheel. The multi-sensor fusion is implemented via algorithm based on Kalman filtering technique. Navigation accuracy can be enhanced using this filtering approach. For the verification of fusion approach, land vehicle test was performed and the results were discussed. Results showed that the horizontal position errors were suppressed around 1 meter level accuracy under simulated non-GPS availability environment. Under normal GPS environment, the horizontal position errors were under 40㎝ in curve trajectory and 27㎝ in linear trajectory, which are definitely depending on vehicular dynamics.

• 대한가정학회지
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• 제44권10호
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• pp.9-20
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• 2006

Due the globalization trends of industry environment, not only fashion companies of the developed countries but also those of NICs and the developing countries are pursuing to globalize their businesses. This study was conducted (i) to identify the characteristics of international marketing mix of Korean fashion companies operating in oversea fashion markets and (ii) to analyze the performance of Korean fashion companies related to international marketing mix. The data were collected from inter-Korean fashion enterprises. A questionnaire was distributed to a person in charge of international division/international trade division who doing business in domestic market and a person in charge of a local subsidiary in oversea market. The methods of analysis used in this study were factor analysis, cluster analysis, and one-way ANOVA. The results of this study are as follows: First, according to factor analysis and cluser analysis, Korean fashion companies were classified in four (4) clusters. The fashion companies in Cluster I put their priority on price. The companies in Cluster II are traditional fashion companies which have relatively low power of product and price. The companies in Cluster III put their priority on product, and the companies in Cluster IV put their priority on local market. Second, according to ANOVA, a growth rate of sales make significant difference among 4 clusters and Clusters II and III were comparatively high in performance.

• 한국게임학회 논문지
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• 제14권4호
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• pp.75-86
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• 2014

본 논문은 차기 한류를 주도할 수 있는 문화콘텐츠로서 게임의 확장 가능성을 타진해 보았다. 게임이 한류문화상품으로 성장하고 확산되기 위해서는 한류게임의 지속성을 유지할 수 있는 새로운 전략을 세우고, 한류게임의 친근성을 확대시켜 호감도를 극대화시키는 스토리텔링을 계획해야 된다는 사실을 인식할 수 있었다. 더불어서 글로벌 시장에서 한국문화를 대변할 수 있는 한국형 문화게임을 개발하고, 현지화전략을 세움과 동시에 정부차원의 종합적인 지원체계를 갖추는 일이 급선무라는 사실을 파악할 수 있었다.