• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.323-333
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• 2011

Due to the limited pendulum motion range, the conventional one-pendulum driven spherical robot has limited driving capability. Especially it can not drive parallel direction with center horizontal axis to which pendulum is attached from stationary state. To overcome the limited driving capability of one-pendulum driven spherical robot, we introduce a spherical robot, called KisBot II, with a new type of curved two-pendulum driving mechanism. A cross-shape frame of the robot is located horizontally in the center of the robot. The main axis of the frame is connected to the outer shell, and each curved pendulum is connected to the end of the other axis of the frame respectively. The main axis and pendulums can rotate 360 degrees inside the sphere orthogonally without interfering with each other, also the two pendulums can rotate identically or independent of each other. Due to this driving mechanism, KisBot II has various motion generation abilities, including a fast steering, turning capability in place and during travelling, and four directions including forward, backward, left, and right from stationary status. Experiments for several motions verify the driving efficiency of the proposed spherical robot.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.121-132
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• 2011

One of the advantages of BOT PF(Project Finance) is the government can be protected from risks involved in projects as the private finances, builds, and operates relevant projects. Moreover, the private may avoid outstanding responsibility in case of default thanks to BOT PF's unique financial structure and characteristics. However, despite increasing attention on risk mitigation effect of financial structure and characteristic of BOT PF to default risk with emerging controversies of capital crunch, introduction of IFRS, and contingent liabilities, valuation of default risk mitigation effect caused by financial structure and characteristics of BOT PF still seems sophisticated due to uncertain cash flows, complexly layered contracts, and their interaction. So, this paper is to show the theoretical frame to assess the default risk mitigation effect of financial structure and characteristic of BOT PF with option pricing and related financial economic theories and to provide some meaningful implications. Finally, this research shows that the financial structure and characteristics of BOT PF help mitigate the default risk and default risk mitigation effect increases as change of relevant variables on financial feasibility gets the BOT project less financially feasible.

• Phonetics and Speech Sciences
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• v.9 no.2
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• pp.69-76
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• 2017

The current study investigated whether Korean learners' English-learning environments, especially target English accent (General American English (GAE) vs. Southern British English (SBE)) and English-language experience affected their production of English vowels. Thirty six EFL learners, 27 ESL-US learners, and 33 ESL-UK learners produced 8 English vowels with a bVt frame (beat, bit, bet, bat, bought, bot, boat, boot). The learners' productions were acoustically analyzed in terms of F1 and F2 frequencies. The overall results revealed that the learners' target accent had an effect on their production of some English vowels. The EFL and ESL-US learners' (especially, female learners') production of bought, bot, boat, and boot, which show characteristic differences between the GAE and SBE accents, was closer to that of the native American English (AE) speakers than the native British English (BE) speakers. In contrast, the ESL-UK learners' production of bought and bot demonstrated the opposite pattern. Thus, the impact of target accent was not demonstrated across the board. The effect of the learners' different English-language experience was also rather limited. This was because the EFL learners' production was not much different from the ESL-US learners' production, in spite of the ESL-US learners' residence in the US for more than 9 years. Furthermore, the Korean learners, irrespective of their different English-language experience, tended to produce bit and bat with lower F1 than the native AE and BE speakers, thus resulting in bit and bat to be produced similarly to beat and bet, respectively. This demonstrates the learners' persistent L1 effects on their English vowel production despite the learners' residence in the English speaking countries or their high English proficiency.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.1
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• pp.56-61
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• 2022

In this paper, we classify and present AI algorithms and natural language processing methods used in chatbots. A framework that can be used to implement a chatbot is also described. A chatbot is a system with a structure that interprets the input string by constructing the user interface in a conversational manner and selects an appropriate answer to the input string from the learned data and outputs it. However, training is required to generate an appropriate set of answers to a question and hardware with considerable computational power is required. Therefore, there is a limit to the practice of not only developing companies but also students learning AI development. Currently, chatbots are replacing the existing traditional tasks, and a practice course to understand and implement the system is required. RNN and Char-CNN are used to increase the accuracy of answering questions by learning unstructured data by applying technologies such as deep learning beyond the level of responding only to standardized data. In order to implement a chatbot, it is necessary to understand such a theory. In addition, the students presented examples of implementation of the entire system by utilizing the methods that can be used for coding education and the platform where existing developers and students can implement chatbots.

• Journal of the Korean earth science society
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• v.37 no.2
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• pp.117-131
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• 2016

The purpose of this study was to compare of freshmen's cognitive frames about the 'Crisis of the Earth' upon taking the Earth science I course in high school to confirm if they reflect the goal of the curriculum reasonably. Data were collected from 67 freshmen who graduated from high school. All participants were asked to express about the 'Crisis of the Earth' in painting with explanation, then we picked meaningful units from paintings. We analyzed the words and frames presented in the paintings using the Semantic Network Analysis. Result are as follows. First, when both groups' (one that took the course vs. the other that did not take it) built their cognitive frames for the 'crisis of the Earth', they reasonably connected areas that are composed of the global environment and they understood that their relation was constantly changing by interacting each other. Second, when configuring a cognitive frame about the 'crisis of the Earth', both groups reflected the characteristics of interrelationship with human activities. In particular, the group that took the course of Earth Science I fully reflected the goal of the curriculum. It is suggested that students recognize the 'crisis of the Earth' not only from a cosmic perspective bot also from the Earth's interior since most of students have strongly connected it to the phenomenon of the Earth's interior rather than the Earth's outward symptoms. In addition, it is recommended that the Earth science curriculum put more emphasis on understanding the importance of problem-solving of the Earth's crisis.