• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.84-91
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• 2008

In this paper, we propose a Sequency domain based BPM-UWB receiver compensating for distortion in the multi-path channel. We give a mathematical derivation for the proposed receiver which exploits a matched filter theory for optimum reception. We also analyze the system performance and present the simulation results that show the performance enhancement of the proposed system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.161-165
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• 2001

최근 인터넷은 전 세계적으로 대중화되고 다양한 분야에서 많이 응용되고 있다. 특히 인터넷을 이용한 Telerobot 시스템의 연구가 활발히 진행되면서, 인터넷상에서의 네트워크 상태나 대역폭에 따른 시간지연 문제가 중요한 이슈가 되고 있다. 이는 조작자가 의도하는 데로 이동로봇을 제어하기 위해 반드시 해결되어야할 문제이다. 따라서 본 논문에서는 원격지의 조작자가 지시하는 데로의 원활한 주행을 위하여 이동로봇에 전송되는 명령에 신간정보를 함께 보냄으로써, 이를 수신한 이동로봇이 지연시간을 계산하여 시간지연에 따른 경로오차를 보상하거나, 이전의 경로를 이용하여 앞으로의 경로를 예측함으로써 이동로봇이 적절한 경로를 주행할 수 있도록 함을 목적으로 한다.

• Journal of the Korea Computer Industry Society
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• v.7 no.1
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• pp.39-46
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• 2006

Multipath diversity reception is applied to the compensation of the distortion of channel, which occurs in transmission of data at rapid speed. DS/BPSK systems are composed of the equipment with reception structure combined with a compensation algorithm to diversity branch. The efficiency of the system is evaluated from the point of view of average bit error rate according to SNR. In order to remove intersymbol interference, this algorithm is applied to time-invariant channel at every diversity branch with the number of L. As a result, the average bit error rate is saturated by $10^{-2}$ at the conventional compensation algorithm.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.2 s.10
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• pp.19-28
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• 2006

In the IEEE 802.15.4a system, they require simple, economical and low power consumption transmitter and receiver to transmit low rate data and to identify distance and location. To meet these requirements, LR-WPAN system use transmitter and receiver with simple modulation and demodulation scheme. In this paper, use PPM+BPSK modulation and windowing scheme to overcome multipath fading effect. Then we apply this channel estimation scheme to LR-WPAN system and compare performance depends on transmitter scheme. Proposed method using preamble to find channel characteristic out and we compensate distorted data with that information. Therefore we can detect signal easily at the demodulation part. Simulation result shows that performance evaluation is greater at the NLOS channel than LOS channel no matter what the receiver scheme.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.63-70
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• 2013

In this paper, we investigated frequency synchronization through computer simulation of digital M/W transmission system in multipath fading channel. we suggested frequency offset correction algorithm against frequency offset between transmitter and receiver, then evaluated the degree of constellation performance enhancement. From the performance evaluation, in case of large frequency offset, although adopting frequency offset correction scheme, residual frequency offset degraded system performance. As a result, according to frequency offset value between transmitter and receiver residual frequency offset affects system performance significantly. The results of this paper should be utilized for frequency synchronization criterion when frequency band of broadcasting system is rearranged.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.321-330
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• 2011

This study focuses on the moderating effect of sex role on the relationship between perceived values on the reward program of tele-communication firms and customer satisfaction. To test moderating effect, Difference test for distinct parameters in Amos 18.0 program was used. Results show that both kind of perceived values(utilitarian value and hedonic value) have a significant effect on customer satisfaction. And the moderating effect of sex variable was verified. For male, hedonic value has influenced on the customer satisfaction more than utilitarian value. And for female, reversely, utilitarian value has influenced on the customer satisfaction more than female value.

• 월간 기계설비
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• s.304
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• pp.112-114
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• 2015

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.237-238
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• 2008

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.883-888
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• 2011

Laparoscopic surgery is being used in various surgical fields because it minimizes scarring. Laparoscopic operations require practical hand skills, so surgeons train on animals and via surgery training tool sets. However, these tool sets do not give the surgeon the sensation of touching real organs. A recently developed laparoscope simulator has a high friction force along the translational axis and a high gravity force along the pitch axis, and therefore it does not permit the operator to control his or her hands delecately. In the paper, the friction force along the axes is auumed to depend on the veolcity, and the gravity force on the angle and distance. We develop a compensation model that combines the gravity and friction force models.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.9
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• pp.281-290
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• 2020

The Vision-and-Language Navigation(VLN) task is a complex intelligence problem that requires both visual and language comprehension skills. In this paper, we propose a new learning model for visual-language navigation agents. The model adopts a hybrid learning that combines imitation learning based on demo data and reinforcement learning based on action reward. Therefore, this model can meet both problems of imitation learning that can be biased to the demo data and reinforcement learning with relatively low data efficiency. In addition, the proposed model uses a novel path-based reward function designed to solve the problem of existing goal-based reward functions. In this paper, we demonstrate the high performance of the proposed model through various experiments using both Matterport3D simulation environment and R2R benchmark dataset.