• KIPS Transactions on Software and Data Engineering
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• v.4 no.5
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• pp.225-230
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• 2015

In this paper, we propose an effective real-time visual loop closure detector, VILODE, which makes use of key frames and bag of visual words (BoW) based on SURF feature points. In order to determine whether the camera has re-visited one of the previously visited places, a loop closure detector has to compare an incoming new image with all previous images collected at every visited place. As the camera passes through new places or locations, the amount of images to be compared continues growing. For this reason, it is difficult for a visual loop closure detector to meet both real-time constraint and high detection accuracy. To address the problem, the proposed system adopts an effective key frame selection strategy which selects and compares only distinct meaningful ones from continuously incoming images during navigation, and so it can reduce greatly image comparisons for loop detection. Moreover, in order to improve detection accuracy and efficiency, the system represents each key frame image as a bag of visual words, and maintains indexes for them using DBoW database system. The experiments with TUM benchmark datasets demonstrates high performance of the proposed visual loop closure detector.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1059-1068
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• 2016

The current operation method for the AVC (Automatic Vehicle Classification) equipment does not generate vehicle speed, traffic volume and vehicle type information when part of the sensors has failed. Inefficiency of current methods would not use the collected data from the normal sensor. In this study was conducted research on the calculating method at the traffic volume and vehicle speed in the sensor failure AVC equipment. The failure situation of the sensor was classified into 4 types. Calculating the traffic volume and vehicle speed information for each type, and accuracy of these informations were analyzed. Analysis results, traffic volume was possible to calculate a highly accurate value (accuracy: 100%, 98%, 97%). In the case of speed, the accuracy of the calculated speed value reaches a level that can be accepted sufficiently (RMSE value is less than 16.8). So, using the methodology proposed in this study are expected to be able to increase the operational efficiency of the AVC equipment.

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.285-290
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• 2020

This paper presents a time synchronization algorithm based on PLL for application to telemetry systems and implement FPGA logic. The large aircraft of the telemetry system acquires status information through each distributed acquisition devices and analyzes the flight status in real time. For this reason, time synchronization between systems is important to improve precision. This paper presents a PLL based time synchronization algorithm that is less complex than other time synchronization methods and takes less time to process data because there is minimized message transmission for synchronization. The validity of proposed algorithm is proved by simulation of Python. And the VHDL logic was implemented in FPGA to check the time synchronization performance.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.161-172
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• 2016

The following research investigates core factors required for IT professionals to achieve and remain happy on their jobs through dynamic and structural CLD and suggests personal, organizational, and government level (happiness) promoting factors. Researcher adopted the system dynamics methodology which is qualitative research techniques pursue behavior probability by using CLD. It spotlights 6 CLD: job satisfaction, organizational commitment, positive sensitivity, negative sensitivity, amicable relationship, job sustainment intention, in addition to numerous factors that affect them from an integrative perspective. It differentiates itself from one-way relationship focused qualitative research to an advanced mutual and realistic perspective exploratory research.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.134-137
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• 2002

This paper presents a robot manipulator kinematic motion control scheme based on velocity feedback loop. The desired joint velocity is obtained by the feature-based visual servoing and is used in the joint velocity control loop system for trajectory control of the robot manipulator. The asymptotic stability of the closed loop system is shown by the Lyapunov method. Effectiveness of the proposed method is shown by simulation and experimental results on a robot manipulator with two degree of freedom.

• Korean System Dynamics Review
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• v.9 no.1
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• pp.33-56
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• 2008

With emphasis on the importance of systems thinking for the establishment of learning organization, Senge in his famous book "The Fifth Discipline", explains in depth four disciplines such as personal mastery, mental models, shared vision, team learning, which are all geared up to the implementation of learning organization. However, two critical pitfalls are found: First, a holistic picture is absent in his presentation of learning organization, which just seems like a puzzle with linking pieces missing between disciplines. Secondly, as is often the case too much details are discussed in expense of insights on each discipline. This paper thus attempts to draw core metaphysical insights underlying Senge's learning organization disciplines by reinterpreting them from oriental perspectives; and to identify mechanisms depicting how they are working together as a whole, which is enabled by exploiting causal loop diagrams as a tool of systems thinking. In addition some thoughts on the implications of systems thinking on each of the learning organization disciplines.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.93-101
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• 2011

For mobile robot, recognizing its current location is very important to navigate autonomously. Especially, loop closing detection that robot recognize location where it has visited before is a kernel problem to solve localization. A considerable amount of research has been conducted on loop closing detection and localization based on appearance because vision sensor has an advantage in terms of costs and various approaching methods to solve this problem. In case of scenes that consist of repeated structures like in corridors, perceptual aliasing in which, the two different locations are recognized as the same, occurs frequently. In this paper, we propose an improved method to recognize location in the scenes which have similar structures. We extracted salient regions from images using visual attention model and calculated weights using distinctive features in the salient region. It makes possible to emphasize unique features in the scene to classify similar-looking locations. In the results of corridor recognition experiments, proposed method showed improved recognition performance. It shows 78.2% in the accuracy of single floor corridor recognition and 71.5% for multi floor corridors recognition.

• Journal of Life Science
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• v.24 no.4
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• pp.428-436
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• 2014

Loop-mediated isothermal amplification (LAMP) technique relies on autocycling strand displacement DNA sysnthesis without template denaturation steps under isothermal conditions. LAMP has more advantages than modern PCR, as it requires only basic laboratory equipment like an isothermal water bath, oven, and heating cabinet. Hence, in this study, five random primers were designed with Streptococcus parauberis, shikimate kinase Arok gene sequences (Genbank accession number: CP0024711). Two primers were selected based on the ladder pattern. Other optimum reaction conditions like temperature, time, and sensitivity were established and confirmed with conventional SYBR-green PCR. Results confirmed that the designed random primers were species specific, without any non-target DNA amplification under isothermal conditions. Hence, this study suggests that LAMP techniques could be used in the diagnosis of fish pathogen, specifically S. parauberis.

• Korean Journal of Cognitive Science
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• v.17 no.1
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• pp.15-27
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• 2006

The effects of the number of Hangul syllable, the nunber/location of batchim in a Hangul word, and compound/noncompound Hangul word on memory span were examined. The results were that (1) the more syllables a word had, the lower us memory span was, (2) the more batchims a two-syllable word had, the lower its memory span was (Korean batchim effect on memory span), (3) noncompound word had higher memory span than compound word. The reading speed of above mentioned words was measured and the results were that (1) the more syllables a word had, the slower its reading speed was, (2) but the reading speed of a two-syllable word was forest when it had a batchim on second syllable than when it had no batchim or had a batchim on first syllable or batchims on both syllables (Korean ending batchim effect on reading speed), (3) noncompound word was read faster thu compound word. Korean ending batchim effect on reading speed was not compatible with the explanation by articulatory loop bur compatible with the explanation by visual cache where the orthographic information was represented. The results suggest that memory span was influenced nor only by phonological information but also by orthographic information.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.771-782
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• 1991

In industrial multivariable plants, it is ofte the case that the plant outputs are measured in similar components not simultaneously but serially. In this paper, the problem of estimating the state vector of the plant based on the data obtained from such a measuring scheme is considered, and a special type of observer(referred to as a $'$multiple serial-sampling$'$ type observer) which renews its internal states whenever a new group of data is obtained is proposed. It is proved that such an observer can be constructed for almost every sampling period if the palnt is observable as a continuous-time multivariable system, and that the poles of the closed-loop system using the multiple serial-sampling type observer consist of the poles of the observer and those of the state feedback system. The behaviors of the observer and the closed-loop system are studied by simulation. The results of simulation indicate that a multiple serial-ampling type observer can estimate the state of the plant more accurately than the ordinary type observers and improve the closed-loop performance, especially, in the existence of measuring noise.ng noise.