• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.997-1005
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• 1998

This paper presents a modified on-off algorithm based on the gradient method for providing the phase of each antenna element more accurately and simply compared to the conventional on-off algorithm. The sup4erisority of theproposed method is due to the fact that the proposed method finds the increase and decrease of the array output power more accurately by utilizing the gradient of array output power with respect to the instantaneous phase of array element. The array antenna adopting to the proposed method formsmaximum beam-pattern along the direction of the desired signal by aligning the phase of every antenna enement. The proposed method is applied to both linear and two-dimentional aray for analyzing the result. The capability of the real-time processing of the proposed technique is confirmed by implementing the proposed algorithm with TMS320C30 Evaluation Module. Since the computational load required to form the beam-pattern per snapshot is small, the proposed method is suitable for the mobile communication system of which the response must be fast. By the results obtained from the application of the proposed method to the CDMA mobile communication environment, it is vreified that the performance of the received signal is consideralbly improved.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.2
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• pp.175-191
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• 2008

In the early stage of industrial development, most of software companies were agglomerated at the CBD(Central Business Districts) in Seoul. However, the spatial distribution pattern of Korean Software industry has been changed according to the propagation of broadband, the change in rents, the governmental policy for industrial districts. In this research, using the software year book at 1997 and 2007, the emerging new pattern was analyzed using spatial clustering analysis. As a results of research, the spatial distribution was expanded in morphological changes. However, it was found that there was not a significant difference in a degree of accumulation. In the aspect of behavioral movement of companies, they tend to be relocated from the CBD to urban fringes and their movement is related to the product life cycle in selecting the clustered place.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.331-338
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• 2017

In this study, a portable x-ray generator was manufactured and a real-time image acquisition system was constructed using the image intensifier from the generated generator. We have developed a real - time position error verification system that can verify whether the artificial joint position is different from the initial image from the acquired image. The template image of the region of interest is extracted from the reference image using the pattern matching technique and compared with the image to be compared. As a result, It is shown that real - time position error verification is achieved by displaying the difference angle. This system is portable type, has a self-shielding facility, and the output of the irradiation device can be manufactured in a small size of 1kw and can be used as a portable type. In case of emergency patients in the non-destructive field for industrial use, It has proved effective for use in small areas such as feet.

• Journal of KIISE
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• v.42 no.2
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• pp.190-202
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• 2015

Much research has been conducted on location-based intelligent personal assistants that can understand a user's intention by learning the user's route model and then inferring the user's destinations and routes using data of GPS and other sensors in a smartphone. The intelligence of the location-based personal assistant is contingent on the accuracy and efficiency of the real-time predictions of the user's intended destinations and routes by processing movement information based on uncertain sensor data. We propose a robust particle filter based on Dynamic Bayesian Network model to infer the user's routes. The proposed robust particle filter includes a particle generator to supplement the incorrect and incomplete sensor information, an efficient switching function and an weight function to reduce the computation complexity as well as a resampler to enhance the accuracy of the particles. The proposed method improves the accuracy and efficiency of determining a user's routes and destinations.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.141-147
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• 2003

The simultaneous expression levels of antifungal activity related genes was analyzed by DNA microarray. We constructed DNA chips contained 2,000 randomly digested genome spots of the antifungal bacterium of Bacillus lentimorbus WJ5 and compared its quantitative aspect with 7 antifungal activity deficient mutants induced by gamma radiation ($^{60}Co$). From the analysis of microarray hybridization by the Gene Cluster (Michael Eisen, Stanford Univ.), totally 408 genes were expressed and 20 genes among them were significantly suppressed in mutants. pbuX (xanthine permease, K222), ywbA (phosphotransferase system enzyme II, K393), ptsG (PTS glucose specific enzyme II ABC component, K877), yufO (ABC transporter (ATP-binding protein), K130l), and ftsY (signal recognition particle (docking protein), K868) were simultaneously down-regulated in all mutants. It suggested that they were supposed to be related to the antifungal activity of B. lentimorbus WJ5.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.204-209
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• 2004

The main purpose of this study was to select a B. schmidtii population which has high cadmium tolerance and remediation and to determine the difference of cadmium uptake patterns among populations. One-year-old B. schmidtii seedlings were treated with 0, 0.4, 0.8mM CdSO$_4$. 3/8H$_2$O for two months. Cadmium concentrations in different positions of stem and cadmium concentrations and contents of leaves, stems and roots were analyzed. Also soil cadmium concentrations were analyzed. B. schmidtii was highest in root and lowest in shoot tip, showing a gradual decrease from root to shoot tip. The shoot to root Cd concentration ratios were over 1.26. It is concluded that B. schmidtii has good potential for phytoextraction as a shoot accumulator, which can be used for remediation of cadmium-contaminated areas. But tolerance differs between populations. Therefore B. schmidtii should be used as a means of phytoremediation after selection for Cd tolerance is performed.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.51-59
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• 2011

This paper is concerned with locomotion of dog-like quadruped robots that can adapt to various terrains, mainly dealing with implementation methods and characteristics of static and dynamic gaits. To this end, a 12-DOF robot is built in house, motional trajectories of its body and feet are generated mimicking biological life, and the corresponding leg joint angles are analytically obtained by inverse kinematics. Such joint angle data are then applied to the robot's ADAMS model for computer simulations so that the planned walk and trot gaits are both confirmed dynamically stable. However, contrary to the simulation results, previous trot patterns showed unstable behavior during experiments. This problem led us to analyze the reason, and in the course we discovered the importance of maximally utilizing the concept of WSM rather than ZMP and therefore reducing the gait period to secure the stability of dynamic gaits such as trot.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.65-74
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• 2012

In this paper, we explore the application of 2-D dual-tree discrete wavelet transform (DDWT), which is a directional and redundant transform, for image coding. DDWT introduces limited redundancy and allows the transform to provide approximate shift invariance and directionally selective filters while preserving the usual properties of perfect reconstruction and computational efficiency with good well-balanced frequency responses. Also, quincunx lattice yields a non separable 2D-wavelet transform, which is also symmetric in both horizontal and vertical direction. And non-separable wavelet transformation can generate sub-images of multiple degrees rotated versions. The proposed 2-D non-separable DDWT can provide efficient approximation for directional features of images schemes, such as edges and contours in images that are not aligned with the horizontal or vertical direction. Finally, non-separable image processing using DDWT services good performance.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.561-566
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• 2003

This paper proposes a new algorithm that generates smooth and realistic transition views from one viewpoint to another view point on the panorama based navigation system. The proposed algorithm is composed with two steps. One is prewarping that aligns the viewing direction in two panorama image, the other is bidirectional disparity morphing (BDM) that generates the intermediate scene from the aligned panorama images. For the prewarping, first of all, we compute the phase correlation between two images in order to get the information such as the displacement, rotation, and scale. Then we align the original images using these information. As soon as finishing the prewarping, we compute the block based disparity vectors (DVs) and smooth them using the two occluding patterns. As we apply these DVs to the BDM, we can get the elaborate intermediate scenes. We make an experiment on the proposed algorithm with real panoramic images and we can get the satisfactory results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.6 s.360
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• pp.48-56
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• 2007

OFDMA (Orthogonal Frequency Division Multiple Access) is widely used as multiple access techniques for next generation mobile communication systems. However, OFDMA has a disadvantage of high peak-to-average power ratio and SC-FDMA (Single-Carrier Frequency Division Multiple Access) was proposed for uplink systems to overcome the drawback. SC-FDMA also has several demerits including degraded performance with high-order modulations or with multiple antenna techniques, and less flexibility in resource allocation and pilot patterns. In order to achieve the best performance over a wide range of environments, each mobile station should select either of OFDMA and SC-FDMA according to the given condition and a pilot structure for SC-FDMA systems should be similar to that of OFDMA to maintain the same frame structure. While conventional SC-FDMA schemes require an entire SC-FDMA symbol or a separate short symbol for pilots, this paper proposes a method which supports the pilots included in SC-FDMA data parts and enables a SC-FDMA frame to hold the same structure as an OFDMA frame.