• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.775-781
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• 2011

For the measurement of absolute position of mobile robot in indoor environments, the ultrasonic positioning systems using ultrasound have been researched for several years. Most of these ultrasonic positioning systems to avoid interference between the ultrasound are used for sequential transmitting. However, due to the use of sequential transmitting, the positions of transmitter to receive an ultrasound will change when the mobile robot moves. Therefore the accuracy of positioning is reduced. In this paper, the new position estimation algorithm with weighting factor according to the time of receipt is proposed. By applying the proposed algorithm to existing Ultrasonic Satellite System(USAT), the improved USAT is configured. The positioning performance of the improved USAT with the proposed position estimation algorithm are verified by experiments.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1382-1396
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• 2017

In this paper, we analyze a recently proposed semi-fragile watermarking scheme based on local binary pattern (LBP) operators, and note that it has a fundamental flaw in the design. In this work, a binary watermark is embedded into image blocks by modifying the neighborhood pixels according to the LBP pattern. However, different image blocks might have the same LBP pattern, which can lead to false detection in watermark extraction process. In other words, one can modify the host image intentionally without affecting its watermark message. In addition, there is no encryption process before watermark embedding, which brings another potential security problem. To illustrate its weakness, two special copy-paste attacks are proposed in this paper, and several experiments are conducted to prove the effectiveness of these attacks. To solve these problems, an improved semi-fragile watermarking based on LBP operators is presented. In watermark embedding process, the central pixel value of each block is taken into account and Arnold transform is adopted to guarantee the security of watermark. Experimental results show that the improved watermarking scheme can overcome the above defects and locate the tampered region effectively.

• ETRI Journal
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• v.43 no.5
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• pp.835-855
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• 2021

With the recent increase in data disclosure, the Comprehensive Knowledge Archive Network (CKAN), which is an open-source data distribution platform, is drawing much attention. CKAN is used together with additional extensions, such as Datastore and Datapusher for data management and Harvest and DCAT for data collection. This study derives the problems of CKAN itself and Harvest Extension. First, CKAN causes two problems of data inconsistency and storage space waste for data deletion. Second, Harvest Extension causes three additional problems, namely source deletion that deletes only sources without deleting data themselves, job stop that cannot delete job during data collection, and service interruption that cannot provide service, even if data exist. Based on these observations, we propose herein an improved CKAN that provides a new deletion function solving data inconsistency and storage space waste problems. In addition, we present an improved Harvest Extension solving three problems of the legacy Harvest Extension. We verify the correctness and the usefulness of the improved CKAN and Harvest Extension functions through actual implementation and extensive experiments.

• Journal of muscle and joint health
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• v.28 no.1
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• pp.50-60
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• 2021

Purpose: The purpose of this study is to verify the effect of improving global health nursing competency, understanding of international development cooperation and satisfaction of education for nursing students through the course of global health in nursing. Methods: This study is a design of similar experiments before and after the non-equivalent control group to verify the difference in degree between global health nursing competency and understanding of international development cooperation by the course of global health in nursing of nursing students. Results: The degree of global health nursing competency of the experimental group that took the course of global health in nursing has significantly improved compared to the control group that did not participate, and a total of 30 detailed items showed significant differences. Conclusion: In this study, the global health nursing competency and understanding of international development cooperation have improved since nursing students took the course of global health in nursing. It suggests that the development and evaluation of nursing curriculum is necessary at a time when the global health nursing competency needs to be improved.

• Journal of Information Processing Systems
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• v.19 no.1
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• pp.17-32
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• 2023

Centralized hierarchical routing protocols are often used to solve the problems of uneven energy consumption and short network life in wireless sensor networks (WSNs). Clustering and cluster head election have become the focuses of WSNs. In this paper, an energy balanced clustering routing algorithm optimized by sine cosine algorithm (SCA) is proposed. Firstly, optimal cluster head number per round is determined according to surviving node, and the candidate cluster head set is formed by selecting high-energy node. Secondly, a random population with a certain scale is constructed to represent a group of cluster head selection scheme, and fitness function is designed according to inter-cluster distance. Thirdly, the SCA algorithm is improved by using monotone decreasing convex function, and then a certain number of iterations are carried out to select a group of individuals with the minimum fitness function value. From simulation experiments, the process from the first death node to 80% only needs about 30 rounds. This improved algorithm balances the energy consumption among nodes and avoids premature death of some nodes. And it greatly improves the energy utilization and extends the effective life of the whole network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.840-860
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• 2023

Aiming at the serious occlusion and slow tracking speed in pedestrian target tracking and recognition in complex scenes, a target tracking method based on improved YOLO v5 combined with Deep SORT is proposed. By merging the attention mechanism ECA-Net with the Neck part of the YOLO v5 network, using the CIoU loss function and the method of CIoU non-maximum value suppression, connecting the Deep SORT model using Shuffle Net V2 as the appearance feature extraction network to achieve lightweight and fast speed tracking and the purpose of improving tracking under occlusion. A large number of experiments show that the improved YOLO v5 increases the average precision by 1.3% compared with other algorithms. The improved tracking model, MOTA reaches 54.3% on the MOT17 pedestrian tracking data, and the tracking accuracy is 3.7% higher than the related algorithms and The model presented in this paper improves the FPS by nearly 5 on the fps indicator.

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.18-21
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• 2017

We report a method for improving heat exchange between cryo-cooled large-power-dissipation devices and liquid cryogen. Micro-machined monolithic heat sinks were fabricated on a high integration density superconducting Josephson device, and studied for their effect on cooling the device. The monolithic heat sink showed a significant enhancement of cooling capability, which markedly improved the device operation under large dc- and microwave power dissipation. The detailed mechanism of the enhancement still needs further modeling and experiments in order to optimize the design of the heat sink.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.210-213
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• 1991

The clamp mode Zero-Volatge-Switched Multi-Resonant-Converter(ZVS-MRC) is proposed. In the converter, the performance of the conventional ZVS-MRC is improved by clamping the drain-to-source voltage of the power switch using a soft switching nondissipative active clamp network. The analysis for each stage of the converter operation modes is presented and is verified by experiments.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1279-1282
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• 2003

Estimation of human motion states is important enabling technologies for realizing a pervasive computing environment. In this paper, an improved method fur estimating human motion state from accelerometer data is introduced. Our method fur estimating human motion state utilizes various statistics of accelerometer data, such as mean, standard variation, skewness, kurtosis, eccentricity, as features for classification, and therefore is expected to be more robust than other existing methods that rely on only a few simple statistics. A series of experiments fur testing the effectiveness of the proposed method has been performed, and its result is presented.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.37-41
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• 1990

The quality of cutting surface such as surface roughness, heat affected zone, serf width can be improved by controlling the parameters of cuting process. These parameters includes cutting velocity, laser beam power, material depth and assistant gas. Thermodynamic analysis and systematical experiments are attempted to pedict and determine the optimal cutting condition. There exists the optimal cutting condition to ensure high quality surface. Under this operation, the minimum surface roughness of the mild steel, the stainless steel and the titanium becomes 3.8${\mu}{\textrm}{m}$ 13${\mu}{\textrm}{m}$ and 10${\mu}{\textrm}{m}$ respectively.