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        검색결과 145

        81.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        In this paper, we propose an algorithm that estimates the location of lunar rover using IMU and vision system instead of the dead-reckoning method using IMU and encoder, which is difficult to estimate the exact distance due to the accumulated error and slip. First, in the lunar environment, magnetic fields are not uniform, unlike the Earth, so only acceleration and gyro sensor data were used for the localization. These data were applied to extended kalman filter to estimate Roll, Pitch, Yaw Euler angles of the exploration rover. Also, the lunar module has special color which can not be seen in the lunar environment. Therefore, the lunar module were correctly recognized by applying the HSV color filter to the stereo image taken by lunar rover. Then, the distance between the exploration rover and the lunar module was estimated through SIFT feature point matching algorithm and geometry. Finally, the estimated Euler angles and distances were used to estimate the current position of the rover from the lunar module. The performance of the proposed algorithm was been compared to the conventional algorithm to show the superiority of the proposed algorithm.
        82.
        2018.09 KCI 등재 서비스 종료(열람 제한)
        Polluting gases emitted from industrial sites take compound forms consisting of gaseous and particulate phases. Localization of PTFE membrane filters has thus been initiated to remove particulate materials and mercury, which is a heavy and hazardous metallic element. More specifically, a PTFE membrane filter was fabricated by thermal laminating technology to vary porosity on the filter surface for removal of particulate materials thereon. Optimized equi-biaxial stretching ratio control enables minimization of large-size pore formation with an average pore size of 0.58 μm and improved air permeability of 8.03 cm3/cm2/sec. Various adsorbents were tested for removal of mercury vapor by surface treatment of the PTFE membrane filter. The filter’s surface was further altered using functional amine group compounds: one composed of silane coupling agent (APTMS) was found suitable as a mercury adsorbent. When ACF with a large surface area was used as support material, mercury removal efficiency increased threefold to 0.162 mg/g-ACF. Furthermore, the developed PTFE membrane filter was tested in its capacity of differential pressure and filtering efficiency using a pilot scale particulate removal unit. Stable and consistent differential pressure was maintained during long-term operation and less frequent periods of filter shutdown due to pores filling with 99.96% of particulate removal efficiency, which was more than satisfactory filtration efficiency.
        83.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        본 연구는 효과적인 게임 현지화 방법에 대한 연구로 게임 텍스트의 번역에 있어 캐릭터성이 미치는 영향력을 증명하고자 한다. 보편적으로 상호작용 스토리텔링의 구조를 가진 게임 속 캐릭터들은 게임 속에서 일어나는 이벤트의 큰 영향력을 가진다. 또한 캐릭터가 특정 문화나 상징에 기반을 둔 경우 필연적으로 스토리와 연계성이 더욱 강해진다. 본 연구는 카발라의 ‘세피로트의 나무’를 바탕으로 캐릭터성이 구성된 게임 ‘로보토미 코퍼레이션’에 등장하는 캐릭터들의 캐릭터성을 분석하고 이를 통해 효과적인 현지화를 위해 게임 번역이 나아가야 할 방향을 제시 하고자 한다.
        84.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        연구자의 개인적․자전적 경험을 바탕으로 한 이 이야기는 내러티브 교육의 현재와 미 래에 관하여 거창한 담론이 아니라 일상적 삶을 엮은 것이다. 그러면서도 이야기의 전반이 ‘내러티브의 한국화’와 ‘이야기의 글로벌화’에 초점이 맞춰지도록 하였다. 그러나 주제에 진입하기에 앞서서 ‘삶의 나눔과 짜임’이라는 내러티브에 대한 나의 가설적 생각과 믿음에 다가가고자 먼저, 과거로 회귀하여 나 자신의 기억 잔상을 부상시켜 플랫폼으로 구성하여 보았다. 그리고 난 후, 그동안 한국에서 이루어진 브루너 및 내러티브 관련 연구를 내 나름대로 개관하여 그 대강을 정리하고 의미를 부여하였다. 마지막으로 내러티브 교육 연구의 방향은 이론 도입이나 소개에서 벗어나 우리 교육계에서 일어나는 내러티브 교육의 실제로 나가야 한다고 제안하고, 보다 구체적인 세 가지 전략을 제시하였다.
        86.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        Purpose - This research addresses the question of how an international retailer like Costco can succeed in a foreign mature market and satisfy the local consumers. Our study aims to promote our understanding of how foreign retailers influence local consumers in a mature market with differentiated business models. Research design, data, and methodology – Our study uses company publications, secondary sources of information and the results of a questionnaire survey consisting of 106 participants. Consumer responses were solicited through a questionnaire survey conducted in the city of Kobe in December of 2013. Results - Product differentiation from local retailers in a mature market like Japan gave Costco a competitive edge. Compared with local supermarkets, Costco was preferred by Japanese consumers for its variety of goods that it carries, as well as in-store promotion large package of selling units, in-store amenities, and customer services. Conclusions - First, a theoretical framework is proposed in this study that can aid in developing localization strategies in a mature market such as Japan. Second, it reveals that an international retailer can succeed in a foreign market by stimulating local consumers to change their purchasing behavior, without having to alter the prevailing format of operation.
        87.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        Planetary global localization is necessary for long-range rover missions in which communication with command center operator is throttled due to the long distance. There has been number of researches that address this problem by exploiting and matching rover surroundings with global digital elevation maps (DEM). Using conventional methods for matching, however, is challenging due to artifacts in both DEM rendered images, and/or rover 2D images caused by DEM low resolution, rover image illumination variations and small terrain features. In this work, we use train CNN discriminator to match rover 2D image with DEM rendered images using conditional Generative Adversarial Network architecture (cGAN). We then use this discriminator to search an uncertainty bound given by visual odometry (VO) error bound to estimate rover optimal location and orientation. We demonstrate our network capability to learn to translate rover image into DEM simulated image and match them using Devon Island dataset. The experimental results show that our proposed approach achieves ~74% mean average precision.
        88.
        2017.11 KCI 등재 서비스 종료(열람 제한)
        Acoustic based localization is essential to operate autonomous robotic systems in underwater environment where the use of sensorial data is limited. This paper proposes a localization method using artificial underwater acoustic sources. The proposed method acquires directional angles of acoustic sources using time difference of arrivals of two hydrophones. For this purpose, a probabilistic approach is used for accurate estimation of the time delay. Then, Gaussian sum filter based SLAM technique is used to localize both acoustic sources and underwater vehicle. It is performed by using bearing of acoustic sources as measurement and inertial sensors as prediction model. The proposed method can handle directional ambiguity of time difference based source localization by generating Gaussian models corresponding to possible locations of both front and back sides. Through these processes, the proposed method can provide reliable localization method for underwater vehicles without any prior information of source locations. The performance of the proposed method is verified by experimental results conducted in a real sea environment.
        89.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        UWB (Ultra Wide Band) refers to a system with a bandwidth of over 500 MHz or a bandwidth of 20% of the center frequency. It is robust against channel fading and has a wide signal bandwidth. Using the IR-UWB based ranging system, it is possible to obtain decimeter-level ranging accuracy. Furthermore, IR-UWB system enables acquisition over glass or cement with high resolution. In recent years, IR-UWB-based ranging chipsets have become cheap and popular, and it has become possible to implement positioning systems of several tens of centimeters. The system can be configured as one-way ranging (OWR) positioning system for fast ranging and TWR (two-way ranging) positioning system for cheap and robust ranging. On the other hand, the ranging based positioning system has a limitation on the number of terminals for localization because it takes time to perform a communication procedure to perform ranging. To overcome this problem, code multiplexing and channel multiplexing are performed. However, errors occur in measurement due to interference between channels and code, multipath, and so on. The measurement filtering is used to reduce the measurement error, but more fundamentally, techniques for removing these measurements should be studied. First, the TWR based positioning was analyzed from a stochastic point of view and the effects of outlier measurements were summarized. The positioning algorithm for analytically identifying and removing single outlier is summarized and extended to three dimensions. Through the simulation, we have verified the algorithm to detect and remove single outliers.
        90.
        2017.08 서비스 종료(열람 제한)
        S100 protein family is small calcium-binding proteins with two EF-hand motifs and comprises more than 20 proteins in human. Although S100A proteins are known to play important roles in proinflammatory responses including damage-associated molecular pattern (DAMP) signaling and in the establishment of pregnancy, the expression of S100As have not been determined in the uterine endometrium during the estrous cycle in pigs. Thus, this study was performed to investigate expression and localization of S100A8, S100A9, and S100A12 in the uterine endometrial tissues during the estrous cycle in pigs. Real-time RT-PCR analysis showed that S100A8, S100A9, and S100A12 mRNAs were expressed in the uterine endometrium during the estrous cycle with higher levels on days 15 and 18 of the estrous cycle than the other days of cycle. Immunohistochemistry analysis showed that S100A9 and S100A12 proteins were mainly localized to the immune cells in the uterine endometrium. Especially, S100A9- and S100A12-positive immune cells were detected in the uterine blood vessels on day 15 of the estrous cycle, and also localized to stroma near to luminal epithelium on days 0 and 18 of the estrous cycle. These results showed that S100As were expressed in the uterine endometrium during the estrous cycle in a cyclic stage-specific manner, and these proteins were localized to the immune cells in the endometrium. These suggest that immune cells expressing S100A proteins may be recruited into the endometrium during the estrous cycle and play an important role in regulating endometrial function in pigs.
        91.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        The localization of the robot is one of the most important factors of navigating mobile robots. The use of featured information of landmarks is one approach to estimate the location of the robot. This approach can be classified into two categories: the natural-landmark-based and artificial-landmark-based approach. Natural landmarks are suitable for any environment, but they may not be sufficient for localization in the less featured or dynamic environment. On the other hand, artificial landmarks may generate shaded areas due to space constraints. In order to improve these disadvantages, this paper presents a novel development of the localization system by using artificial and natural-landmarks-based approach on a topological map. The proposed localization system can recognize far or near landmarks without any distortion by using landmark tracking system based on top-view image transform. The camera is rotated by distance of landmark. The experiment shows a result of performing position recognition without shading section by applying the proposed system with a small number of artificial landmarks in the mobile robot.
        92.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        For the underwater localization, acoustic sensor systems are widely used due to greater penetration properties of acoustic signals in underwater environments. On the other hand, the good penetration property causes multipath and interference effects in structured environment too. To overcome this demerit, a localization method using the attenuation of electro-magnetic(EM) waves was proposed in several literatures, in which distance estimation and 2D-localization experiments show remarkable results. However, in 3D-localization application, the estimation difficulties increase due to the nonuniform (doughnut like) radiation pattern of an omni-directional antenna related to the depth direction. For solving this problem, we added a depth sensor for improving underwater 3D-localization with the EM wave method. A micro scale pressure sensor is located in the mobile node antenna, and the depth data from the pressure sensor is calibrated by the curve fitting algorithm. We adapted the depth(z) data to 3D EM wave pattern model for the error reduction of the localization. Finally, some experiments were executed for 3D localization with the fast calculation and less errors.
        93.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        For a practical mobile robot team such as carrying out a search and rescue mission in a disaster area, the localization have to be guaranteed even in an environment where the network infrastructure is destroyed or a global positioning system (GPS) is unavailable. The proposed architecture supports localizing robots seamlessly by finding their relative locations while moving from a global outdoor environment to a local indoor position. The proposed schemes use a cooperative positioning system (CPS) based on the two-way ranging (TWR) technique. In the proposed TWR-based CPS, each non-localized mobile robot act as tag, and finds its position using bilateral range measurements of all localized mobile robots. The localized mobile robots act as anchors, and support the localization of mobile robots in the GPS-shadow region such as an indoor environment. As a tag localizes its position with anchors, the position error of the anchor propagates to the tag, and the position error of the tag accumulates the position errors of the anchor. To minimize the effect of error propagation, this paper suggests the new scheme of full-mesh based CPS for improving the position accuracy. The proposed schemes assuring localization were validated through experiment results.
        94.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        A rectangle-based relative localization method is proposed for a mobile robot based on a novel geometric formulation. In an artificial environment where a mobile robot navigates, rectangular shapes are ubiquitous. When a scene rectangle is captured using a camera attached to a mobile robot, localization can be performed and described in the relative coordinates of the scene rectangle. Especially, our method works with a single image for a scene rectangle whose aspect ratio is not known. Moreover, a camera calibration is unnecessary with an assumption of the pinhole camera model. The proposed method is largely based on the theory of coupled line cameras (CLC), which provides a basis for efficient computation with analytic solutions and intuitive geometric interpretation. We introduce the fundamentals of CLC and describe the proposed method with some experimental results in simulation environment.
        95.
        2015.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        By adopting a 2D time-dependent wave code, we investigate how mode-converted waves at the Ion-Ion Hybrid (IIH) resonance and compressional waves propagate in 2D density structures with a wide range of field-aligned wavenumbers to background magnetic fields. The simulation results show that the mode-converted waves have continuous bands across the field line consistent with previous numerical studies. These waves also have harmonic structures in frequency domain and are localized in the field-aligned heavy ion density well. Our results thus emphasize the importance of a field-aligned heavy ion density structure for ultra-low frequency wave propagation, and suggest that IIH waves can be localized in different locations along the field line.
        96.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        Environmental conditions during early mammalian embryo development are critical and some adaptational phenomena are observed. However, the mechanisms underlying them remain largely masked. Previously, we reported that AQP5 expression is modified by the environmental condition without losing the developmental potency. In this study, AQP11 was examined instead. To compare expression pattern between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP11 by whole mount immunofluorescence. When the fertilized embryos were developed in the maternal tracts, the level of Aqp11 transcripts was decreased dramatically until 2-cell stage. Its level increased after 2-cell stage and peaked at 4-cell stage, but decreased again dramatically until morula stage. Its transcript level increased again at blastocyst stage. In contrast, the levels of Aqp11 transcript in embryos cultured in vitro were as follows. The patterns of expression were similar but the overall levels were low compared with those of embryos grown in the maternal tracts. AQP11 proteins were localized in submembrane cytoplasm of embryos collected from maternal reproductive tracts. The immune-reactive signals were detected in both trophectoderm and inner cell mass. However, its localization was altered in in vitro culture condition. It was localized mainly in the plasma membrane of the blastocysts contacting with external environment. The present study suggests that early stage embryo can develop successfully by themselves adapting to their environmental condition through modulation of the expression level and localization of specific genes like AQP11.
        97.
        2015.02 KCI 등재 서비스 종료(열람 제한)
        This paper proposes a study for accurate surface localization system using DWT(Discrete Wavelet Transform) and GPS/INS fusion algorithm. Because the propagation in the underwater is not passed by characteristics of the medium unlike the ground, the sonar system like DVL is used instead of GPS. But since these systems are installed on the seafloor and operated, a long time is required for installation and navigation systems are limited outside of the range area. And it is difficult to estimate position in a three-dimensional considering the depth in actual marine environment. In this paper, before the development of underwater localization system, precisely estimated position system is proposed in a two-dimensional by developing surface localization system using removing noise and disturbance with DWT and relatively inexpensive GPS and INS sensor.
        98.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        This paper proposes an underwater localization algorithm using probabilistic object recognition. It is organized as follows; 1) recognizing artificial objects using imaging sonar, and 2) localizing the recognized objects and the vehicle using EKF(Extended Kalman Filter) based SLAM. For this purpose, we develop artificial landmarks to be recognized even under the unstable sonar images induced by noise. Moreover, a probabilistic recognition framework is proposed. In this way, the distance and bearing of the recognized artificial landmarks are acquired to perform the localization of the underwater vehicle. Using the recognized objects, EKF-based SLAM is carried out and results in a path of the underwater vehicle and the location of landmarks. The proposed localization algorithm is verified by experiments in a basin.
        99.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        Acoustic signal is crucial for the autonomous navigation of underwater vehicles. For this purpose, this paper presents a method of acoustic source localization. The proposed method is based on the probabilistic estimation of time delay of acoustic signals received by two hydrophones. Using Bayesian update process, the proposed method can provide reliable estimation of direction angle of the acoustic source. The acquired direction information is used to estimate the location of the acoustic source. By accumulating direction information from various vehicle locations, the acoustic source localization is achieved using extended Kalman filter. The proposed method can provide a reliable estimation of the direction and location of the acoustic source, even under for a noisy acoustic signal. Experimental results demonstrate the performance of the proposed acoustic source localization method in a real sea environment.
        100.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        Adaptive development of early stage embryo is well established and recently it is explored that the mammalian embryos also have adaptive ability to the stressful environment. However, the mechanisms are largely unknown. In this study, to evaluate the possible role of aquaporin in early embryo developmental adaptation, the expression of aquaporin (AQP) 5 gene which is detected during early development were examined by the environmental condition. To compare expression patterns between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP5 by whole mount immunofluorescence. At in vivo condition, Aqp5 expressed in oocyte and in all the stages of preimplantation embryo. It showed peak at 2-cell stage and decreased continuously until morula stage. At in vitro condition, Aqp5 expression pattern was similar with in vivo embryos. It expressed both at embryonic genome activation phase and second mid-preimplantation gene activation phase, but the fold changes were modified between in vivo embryos and in vitro embryos. During in vivo development, AQP5 was mainly localized in apical membrane of blastomeres of 4-cell and 8-cell stage embryos, and then it was localized in cytoplasm. However, the main localization area of AQP5 was dramatically shifted after 8-cell stage from cytoplasm to nucleus by in vitro development. Those results explore the modification of Aqp5 expression levels and location of its final products by in vitro culture. It suggests that expression of Aqp5 and the roles of AQP5 in homeostasis can be modulated by in vitro culture, and that early stage embryos can develop successfully by themselves adapting to their condition through modulation of the specific gene expression and localization.
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