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Adaptive Data Transmission Method According to Wireless State in Long Range Wide Area Networks

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Computers, Materials & Continua 2020年第7期64卷 1-15页

作者： Seokhoon kim dae-young kim Department of Computer Software Engineering Soonchunhyang UniversityAsan-si31538Korea School of Computer Software Daegu Catholic UniversityGyeongsan-si38430Korea

The Internet of Things(IoT)has enabled various intelligent services,and IoT service range has been steadily extended through long range wide area communication technologies,which enable very long distance wireless data ***-nodes are connected to a gateway with a single *** consume very low-power,using very low data rate to deliver *** long transmission time is consequently needed for each data packet transmission in long range wide area networks,data transmission should be efficiently ***,this paper proposes a multicast uplink data transmission mechanism particularly for bad network *** delay will be increased if only retransmissions are used under bad network ***,employing multicast techniques in bad network conditions can significantly increase packet delivery ***,retransmission can be reduced and hence transmission efficiency ***,the proposed method adopts multicast uplink after network condition *** predict network conditions,the proposed method uses a deep neural network *** proposed method performance was verified by comparison with uplink unicast transmission only,confirming significantly improved performance.

关键词： IoT wide area communication machine learning uplink transmission.

A Data Download Method from RSUs Using Fog Computing in Connected Vehicles

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Computers, Materials & Continua 2019年第5期59卷 375-387页

作者： dae-young kim Seokhoon kim School of Information Technology Daegu Catholic UniversityGyeongsan-si 38430Republic of Korea Department of Computer Software Engineering Soonchunhyang UniversityAsan-si 31538Republic of Korea

Communication is important for providing intelligent services in connected *** must be able to communicate with different places and exchange information while *** service operation,connected vehicles frequently attempt to download large amounts of *** can request data downloading to a road side unit(RSU),which provides infrastructure for connected *** RSU is a data bottleneck in a transportation system because data traffic is concentrated on the ***,it is not appropriate for a connected vehicle to always attempt a high speed download from the *** the mobile network between a connected vehicle and an RSU has poor connection quality,the efficiency and speed of the data download from the RSU is *** problem affects the quality of the user ***,it is important for a connected vehicle to connect to an RSU with consideration of the network conditions in order to try to maximize download *** proposed method maximizes download speed from an RSU using a machine learning *** collect and learn from network data,fog computing is used.A fog server is integrated with the RSU to perform *** the algorithm recognizes that conditions are not good for mass data download,it will not attempt to download at high ***,the proposed method can improve the efficiency of high speed *** conclusion was validated using extensive computer simulations.

关键词： Connected car fog computing data download DSRC machine learning

Data Aggregation-based Transmission Method in Ultra-Dense Wireless Networks

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Intelligent Automation & Soft Computing 2023年第1期35卷 727-737页

作者： dae-young kim Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea

As the Internet of Things(IoT)advances,machine-type devices are densely deployed and massive networks such as ultra-dense networks(UDNs)are *** devices attend to the network to transmit data using machine-type communication(MTC),whereby numerous,various are *** devices generally have resource constraints and use wireless *** this kind of network,data aggregation is a key function to provide transmission *** can reduce the number of transmitted data in the network,and this leads to energy saving and reducing transmission *** order to effectively operate data aggregation in UDNs,it is important to select an aggregation point *** total number of transmitted data may vary,depending on the aggregation point to which the data are ***,in this paper,we propose a novel data aggregation scheme to select the appropriate aggregation point and describe the data transmission method applying the proposed aggregation *** addition,we evaluate the proposed scheme with extensive computer *** performances in the proposed scheme are achieved compared to the conventional approach.

关键词： Data aggregation data transmission ultra-dense network machine-type communication Internet of Things

LoRa Backscatter Network Efficient Data Transmission Using RF Source Range Control

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Computers, Materials & Continua 2023年第2期74卷 4015-4025页

作者： dae-young kim SoYeon Lee Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea Department of Software Convergence Soonchunhyang UniversityAsan31538Korea

Networks based on backscatter communication provide wireless data transmission in the absence of a power source.A backscatter device receives a radio frequency(RF)source and creates a backscattered signal that delivers data;this enables new services in battery-less domains with massive Internet-of-Things(IoT)*** is highly energy-efficient in the context of massive IoT ***,long-range(LoRa)backscattering facilitates large IoT services.A backscatter network guarantees timeslot-and contention-based ***-based transmission ensures data transmission,but is not scalable to different numbers of transmission *** contention-based transmission is used,collisions are *** reduce collisions and increase transmission efficiency,the number of devices transmitting data must be *** control device activation,the RF source range can be modulated by adjusting the RF source power during LoRa *** reduces the number of transmitting devices,and thus collisions and retransmission,thereby improving transmission *** performed extensive simulations to evaluate the performance of our method.

关键词： Backscatter communication LoRa backscatter RF source range control activated device control internet of things

Context Awareness by Noise-Pattern Analysis of a Smart Factory

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Computers, Materials & Continua 2023年第8期76卷 1497-1514页

作者： So-Yeon Lee Jihoon Park dae-young kim Department of Software Convergence Soonchunhyang UniversityAsan31538Korea Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea

Recently,to build a smart factory,research has been conducted to perform fault diagnosis and defect detection based on vibration and noise signals generated when a mechanical system is driven using deep-learning technology,a field of artificial *** of the related studies apply various audio-feature extraction techniques to one-dimensional raw data to extract sound-specific features and then classify the sound by using the derived spectral image as a training ***,compared to numerical raw data,learning based on image data has the disadvantage that creating a training dataset is very ***,we devised a two-step data preprocessing method that efficiently detects machine anomalies in numerical raw *** the first preprocessing process,sound signal information is analyzed to extract features,and in the second preprocessing process,data filtering is performed by applying the proposed *** efficient dataset was built formodel learning through a total of two steps of data *** addition,both showed excellent performance in the training accuracy of the model that entered each dataset,but it can be seen that the time required to build the dataset was 203 s compared to 39 s,which is about 5.2 times than when building the image dataset.

关键词： Noise-pattern recognition context awareness deep learning fault detection smart factory

Development of Cloud Based Air Pollution Information System Using Visualization

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Computers, Materials & Continua 2019年第6期59卷 697-711页

作者： SangWook Han JungYeon Seo dae-young kim SeokHoon kim HwaMin Lee Deptartment of Computer Science and Engineering Soonchungyang UniversityAsan31538Korea School of Information Technology Engineering Daegu Catholic UniversityGyeongsan38430Korea Department of Computer Software and Engineering Soonchungyang UniversityAsan31538Korea

Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human *** there are too few fine dust measuring stations and the installation cost of fine dust measuring station is very *** this paper,we propose Cloud-based air pollution information system using *** measure fine dust,we have developed an inexpensive measuring device and studied the technique to accurately measure the concentration of fine dust at the user’s *** we have developed the smartphone application to provide air pollution *** our system,we provide collected data based analytical results through effective data *** system provides information on fine dust value and action tips through the air pollution information *** it supports visualization on the map using the statistical program *** user can check the fine dust statistics map and cope with fine dust accordingly.

关键词： Air pollution visualization R big data cloud clusters

Edge Cloud Selection in Mobile Edge Computing(MEC)-Aided Applications for Industrial Internet of Things(IIoT)Services

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Computer Systems Science & Engineering 2023年第11期47卷 2049-2060页

作者： dae-young kim SoYeon Lee MinSeung kim Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea Department of Software Convergence Soonchunhyang UniversityAsan31538Korea

In many IIoT architectures,various devices connect to the edge cloud via gateway *** data processing,numerous data are delivered to the edge *** data to an appropriate edge cloud is critical to improve IIoT service *** are two types of costs for this kind of IoT network:a communication cost and a computing *** service efficiency,the communication cost of data transmission should be minimized,and the computing cost in the edge cloud should be also ***,in this paper,the communication cost for data transmission is defined as the delay factor,and the computing cost in the edge cloud is defined as the waiting time of the computing *** proposed method selects an edge cloud that minimizes the total cost of the communication and computing *** is,a device chooses a routing path to the selected edge cloud based on the *** proposed method controls the data flows in a mesh-structured network and appropriately distributes the data processing *** performance of the proposed method is validated through extensive computer *** the transition probability from good to bad is 0.3 and the transition probability from bad to good is 0.7 in wireless and edge cloud states,the proposed method reduced both the average delay and the service pause counts to about 25%of the existing method.

关键词： Industrial Internet of Things(IIoT)network IIoT service mobile edge computing(MEC) edge cloud selection MEC-aided application

Characteristics of Algal Succession Following Rock Scraping at Imwon Area in the East Coast of Korea

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Journal of Ocean University of China 2016年第6期15卷 1087-1093页

作者： young dae kim Jung Kwan Alan Myung Mo Nam Chu Lee Hyun Il Yoo Su Yeoung Yeon young Hwan kim Jang Kyun kim Jae Suk Choi East Sea Fisheries Research Institute National Fisheries Research & Development Institute Gangneung 210-860Republic of Korea Korea National Park Service National Park Research Institute Yeosu 550-833 Republic of Korea Seaweed Research Center 1rational Fisheries Research & Development lnstituie Mokpo 530-831 Republic of Korea Department of Biology Chungbuk National University Chongju 361-763 Republic Of Korea Department of Marine Science School of Natural Sciences Incheon National University 22012 Yeonsu-gu Incheon Korea Department of Marine Sciences University of Connecticut 06901 Stamford Connecticut USA Division of Bioindustry Silla University Sasang-gu Busan 617-736 Republic of Korea

Abstract This study was conducted to clarify the characteristics high-pressure water sprayer in the period from June 2010 to April 2011 of algal succession following rock scraping using hoe or We divided the research area off the eastern coast of Korean near Imwon into 3 categories depending upon the severity of the barren ground, i.e., the urchin barren-affected, urchin bar- ren-ongoing and urchin barren-free areas. In April 2011, in the urchin barren-affected area with 25 seaweed species, the cover per- centage and importance value （IV） of erustose coralline algae were higher than those of other species. In the urchin barren-ongoing area with 33 seaweed species, crustose coralline algae （mean IV=62%） as well as Sargassum sp. （mean IV=28%）, and Gelidium amansii （mean IV= 19%） were observed following rock scraping. In the urchin barren-free area where seaweed communities were relatively abundant with 42 species, a variety of algal species including G. amansii （mean IV = 32%） underwent algal succession. Overall, it was observed that, as an aspect of algal succession, the weaker the barren ground severity was, the more frequent and di- verse the seaweeds were, and the more complex the succession pattern was in the study. As an aspect of recovering algal community, rock scraping using hoe was shown to be superior to the method using high-pressure water spraying. Therefore, we conclude that rock scraping using hoe is a very effective strategy for recovering the algal community in urchin barren-ongoing area.

关键词： algal succession sea-urchin barren ground rock scraping subtidal zone

Dual in-situ observation of tribochemical and morphological evolution of single-layer WS_(2)and multi-layer WS_(2)/C coatings

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Friction 2024年第7期12卷 1580-1598页

作者： Yuzhen LIU Jae-Ho HAN Shusheng XU young Chan JUNG dae-Eun kim State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Department of Mechanical Engineering Yonsei UniversitySeoul03722Republic of Korea Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 264000China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Yantai 264000China

The outstanding tribological performance of transition metal dichalcogenides(TMDs)is attributed to their unique sandwich microstructure and low interlayer shear *** advantageous structure allows TMDs to demonstrate exceptional friction reduction ***,the incorporation of TMDs and amorphous carbon(a-C)in multi-layer structures shows excellent potential for further enhancing tribological and anti-oxidation *** carbon,known for its high ductility,chemical inertness,and excellent wear resistance,significantly contributes to the overall performance of these multi-layer *** gain an in-depth understanding of the tribological mechanism and evolution of TMDs’multi-layer coatings,a dual in-situ analysis was carried out using a tribometer equipped with a 3D laser microscope and a Raman *** innovative approach allowed for a comprehensive evolution of the tribological,topographical,and tribochemical characteristics of both single-layer WS_(2)and multi-layer WS_(2)/C coatings in real *** findings from the dual in-situ tribotest revealed distinct failure characteristics between the single-layer WS_(2)coating and the multi-layer WS_(2)/C *** single-layer WS_(2)coating predominantly experienced failure due to mechanical removal,whereas a combination of mechanical removal and tribochemistry primarily influenced the failure of the multi-layer WS_(2)/C *** tribological evolution process of these two coatings can be classified into four stages on the basis of their tribological behavior:the running-in stage,stable friction stage,re-deposition stage,and lubrication failure *** stage represents a distinct phase in the tribological behavior of the coatings and contributes to our understanding of their behavior during sliding.

关键词： In-situ analysis multi-layer coating tribology tribochemistry