• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.61-65
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• 2014

In this paper, we propose a method using cooperative spectrum sensing to avoid multipath and frequency selective fading. One of methods in conventional scheme was multi input multi output (MIMO) solution. However, in the wireless environment, mobile device hardly supports multi antenna because of limitation of hardware. Motivated from above problems, the proposed method provides the information of excellent channel to transmitter. As a result, quality of service (QoS) required by users can be satisfied. Finally, performance of the proposed protocol is analyzed in term of bit error rate (BER).

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.208-222
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• 2015

For the performance-efficient integration of IPs on an SoC utilizing heterochronous multi-clock domains, we propose a synchronization scheme that causes low latency overhead when data are crossing clock boundaries. The proposed synchronization scheme is composed of a clock predictor and a synchronizer. The clock predictor of a sender clock domain produces a predicted clock that is used in a receiver clock domain to detect possible synchronization failures in advance. When the possible synchronization failures are detected, a synchronizer at the receiver delays data-capture times to avoid the possible synchronization failures. From the simulation of the proposed scheme through SPICE modeling using a Chartered $0.18{\mu}m$ CMOS process, we verified the functionalities and timing behavior of the clock predictor and the synchronizer. The simulation results show that the clock predictor produces a predicted clock before a synchronization failure, and the synchronizer samples data correctly using the predicted clock.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2387-2392
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• 2003

In this paper, We designed the local path planning direction algorithmusing fuzzy controller applied fuzzy logic. Algorithm decieded a direction angle by theposition of obstacle, the distance with obstacle, the progress direction of robot, the speed of vehicles and the perception area of sensor. The robot designed with proposed algorithm carried out soft moving without any particular operation, and we could observe that it had very soft curved moving as if an expert drove.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1057-1058
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• 2008

In this paper, the algorithm and the computer simulation of a effective homing navigation system are presented. it is a combination of Path integration by using population coding and neural network and simple avoidance obstacle algorithm. Also, through the computer simulation, we demonstrated the feasibility of the suggested method.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.136-137
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• 2016

WSN의 활용 분야 중 하나로 표준화된 IEEE 802.15.4 WBAN(wireless body area networks)은 웨어러블 디바이스의 무선 통신환경을 고려한 기술이다. WBAN은 높은 밀집도를 가지는 특징을 가지며, 이로 인하여 데이터 충돌이 큰 이슈가 되고 있다. 본 논문에서는 WBAN의 표준에서 제시한 메시지 우선순위를 백오프 알고리즘에 적용하여 WBAN 환경에 더 효율적인 전송을 제공하는 것을 목표로한다.

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.251-260
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• 2015

Propofol is an anesthetic agent that gained wide use because of its fast induction of anesthesia and rapid recovery post-anesthesia. However, previous studies have reported immediate neurodegeneration and long-term impairment in spatial learning and memory from repeated neonatal propofol administration in animals. Yet, none of those studies has explored the sex-specific long-term physical changes and behavioral alterations such as social (sociability and social preference), emotional (anxiety), and other cognitive functions (spatial working, recognition, and avoidance memory) after neonatal propofol treatment. Seven-day-old Wistar-Kyoto (WKY) rats underwent repeated daily intraperitoneal injections of propofol or normal saline for 7 days. Starting fourth week of age and onwards, rats were subjected to behavior tests including open-field, elevated-plus-maze, Y-maze, 3-chamber social interaction, novel-object-recognition, passive-avoidance, and rotarod. Rats were sacrificed at 9 weeks and hippocampal protein expressions were analyzed by Western blot. Results revealed long-term body weight gain alterations in the growing rats and sex-specific impairments in spatial (female) and recognition (male) learning and memory paradigms. A markedly decreased expression of hippocampal NMDA receptor GluN1 subunit in female- and increased expression of AMPA GluR1 subunit protein expression in male rats were also found. Other aspects of behaviors such as locomotor activity and coordination, anxiety, sociability, social preference and avoidance learning and memory were not generally affected. These results suggest that neonatal repeated propofol administration disrupts normal growth and some aspects of neurodevelopment in rats in a sex-specific manner.

• Journal of Science Education
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• v.42 no.1
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• pp.80-93
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• 2018

This study tried to investigate whether it is appropriate to define the emotions of elementary school teachers, who avoid teaching science, as science teaching anxiety through exploring elementary school teachers' emotional expressions and related factors. 10 elementary school teachers who were reluctant to teach science participated in the research, and they presented their thoughts and feelings about teaching science through semi-structured interviews. As a result of analyzing the emotional expressions in the interview, 28 expressions of emotions appeared. Emotional expressions were divided into three types according to the degree of inclusion of factors related to anticipation in related situations. These results show that there are some emotional expressions that cannot be interpreted as the science teaching anxiety. Therefore, we propose to consider science teaching avoidance emotion not as science teaching anxiety but as a mixture of various emotions.

• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.167-178
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• 2012

Objectives : The purpose of this research is to examine the effects of the goal achievement orientation of the students in dental-hygiene practice classes on their self-efficacy and on their adaptation to and satisfaction with their major. Methods : A survey was conducted among the dental-hygiene students in schools located in the Daegu region on October 24-31, 2011. A total of 212 accomplished questionnaires were gathered as sources of final analytical data. Statistical analysis was conducted on the collected data, using the SPSS 19.0 program. Results : 1. The students who had good personal relationships(p=.000) and who chose their major and school based on their aptitude(p=.029) were found to have a higher degree of satisfaction than those who did not have good personal relationships and who did not choose their major and school based on their aptitude. 2. Self-confidence(p=.004), self-control efficacy(p=.000), mastery approach(p=.000), and performance approach(p=.003) were found to have positive correlations with major adaptation while task difficulty preference(p=.000) was found to have a negative correlation with the same. 3. Self-confidence(p=.004), self-control efficacy(p=.000), mastery approach(p=.000), and performance approach(p=.045) were also found to have a positive correlation with major satisfaction while task difficulty preference(p=.000) was found to have a negative correlation with the same. 4. Mastery approach(p=.000) in goal achievement orientation was found to have a positive effect on self-efficacy while mastery avoidance(p=.001) was found to have a negative effect on the same. Mastery avoidance showed the greatest effect on self-confidence(p=.000) while mastery approach showed the greatest effect on self-control efficacy(p=.000) and task difficulty preference(p=.000). 5. In goal achievement orientation, mastery approach(p=.000) was found to have a positive effect on major adaptation while mastery avoidance was found to have a negative effect on the same. Meanwhile, with regard to self-efficacy, self-control efficacy(p=.037) and task difficulty preference(p=.008) were found to have positive effects on major adaptation. 6. In the case of major satisfaction, mastery approach(p=.000) in goal achievement orientation was found to have a positive effect on it, and in self-efficacy, self-control efficacy(p=.038) and task difficulty preference(p=.002) were found to have positive effects on it. Conclusions : Accordingly, to raise the level of the dental-hygiene students' adaptation to and satisfaction with their major, the students should be given appropriate tasks so that they can raise their mastery goal, and they should be encouraged to raise their approach goal rather than their avoidance goal. In addition, the students should be provided assistance in setting self-expectations and in developing confidence in their capabilities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.178-188
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• 2019

When using a distributed system, it is very important to know the intention of a target ship in order to prevent collisions. The action taken by a certain ship for collision avoidance and the action of the target ship it intends to avoid influence each other. However, it is difficult to establish a collision avoidance plan in consideration of multiple-ship situations for this reason. To solve this problem, a Distributed Stochastic Search Algorithm (DSSA) has been proposed. A DSSA searches for a course that can most reduce cost through repeated information exchange with target ships, and then indicates whether the current course should be maintained or a new course should be chosen according to probability and constraints. However, it has not been proven how the parameters used in DSSA affect collision avoidance actions. Therefore, in this paper, I have investigated the effect of the parameters and weight factors of DSSA. Experiments were conducted by combining parameters (time window, safe domain, detection range) and weight factors for encounters of two ships in head-on, crossing, and overtaking situations. A total of 24,000 experiments were conducted: 8,000 iterations for each situation. As a result, no collision occurred in any experiment conducted using DSSA. Costs have been shown to increase if a ship gives a large weight to its destination, i.e., takes selfish behavior. The more lasting the expected position of the target ship, the smaller the sailing distance and the number of message exchanges. The larger the detection range, the safer the interaction.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.3
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• pp.945-953
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• 2018

In this paper, we use 3-D LIDAR for obstacle detection and avoidance maneuver for autonomous unmanned operation. It is aimed to avoid obstacle avoidance in unmanned water under marine condition using only single sensor. 3D lidar uses Quanergy's M8 sensor to collect surrounding obstacle data and includes layer information and intensity information in obstacle information. The collected data is converted into a three-dimensional Cartesian coordinate system, which is then mapped to a two-dimensional coordinate system. The data including the obstacle information converted into the two-dimensional coordinate system includes noise data on the water surface. So, basically, the noise data generated regularly is defined by defining a hypothetical region of interest based on the assumption of unmanned water. The noise data generated thereafter are set to a threshold value in the histogram data calculated by the Vector Field Histogram, And the noise data is removed in proportion to the amount of noise. Using the removed data, the relative object was searched according to the unmanned averaging motion, and the density map of the data was made while keeping one cell on the virtual grid map. A polar histogram was generated for the generated obstacle map, and the avoidance direction was selected using the boundary value.