• Journal of Information Processing Systems
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• v.17 no.1
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• pp.37-50
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• 2021

Query applications based on nested data, the most commonly used form of data representation on the web, especially precise query, is becoming more extensively used. MapReduce, a distributed architecture with parallel computing power, provides a good solution for big data processing. However, in practical application, query requests are usually concurrent, which causes bottlenecks in server processing. To solve this problem, this paper first combines a column storage structure and an inverted index to build index for nested data on MapReduce. On this basis, this paper puts forward an optimization strategy which combines query execution service tree and frequent sub-query trajectory to reduce the response time of frequent queries and further improve the efficiency of multi-user concurrent queries on large scale nested data. Experiments show that this method greatly improves the efficiency of nested data query.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.276-282
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• 2022

One of the most essential foundations upon which big institutions rely in delivering cloud computing and hosting services, as well as other kinds of multiple digital services, is the security of infrastructures for digital and information services throughout the world. Distributed denial-of-service (DDoS) assaults are one of the most common types of threats to networks and data centers. Denial of service attacks of all types operates on the premise of flooding the target with a massive volume of requests and data until it reaches a size bigger than the target's energy, at which point it collapses or goes out of service. where it takes advantage of a flaw in the Transport Control Protocol's transmitting and receiving (3-way Handshake) (TCP). The current study's major focus is on an architecture that stops DDoS attacks assaults by producing code for DDoS attacks using a cloud controller and calculating Round-Tripe Time (RTT).

• Electronics and Telecommunications Trends
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• v.37 no.5
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• pp.54-61
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• 2022

Data are an essential resource for artificial intelligence-based services. It is considered a vital resource in the 4th industrial revolution era based on artificial intelligence. However, it is well-known that only a few giant platforms that provide most of the current online services tend to monopolize personal data. Therefore, some governments have started enforcing personal data protection and mobility regulations to address this problem. Additionally, there are some notable activities from a technical perspective, and Web 3.0 is one of these. Web 3.0 focuses on distributed architecture to protect people's data sovereignty. An important technical challenge of Web 3.0 is how to facilitate the personal data storage technology to provide valuable data for new data-based services while providing data for producers' sovereignty. This study reviews some currently proposed personal data storage technologies. Furthermore, we discuss the domestic countermeasures from MyData perspective, which is a typical project for data-based businesses in Korea.

• Journal of Multimedia Information System
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• v.9 no.3
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• pp.209-218
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• 2022

Industrial IoT applications, including smart factories, require two problem-solving to build data monitoring systems required by services from distributed IoT sensors (smart sensors). One is to overcome proprietary protocols, data formats, and hardware differences and to uniquely identify and connect IoT sensors, and the other is to overcome the problem of changing the server-side data storage structure and sensor data transmission format according to the addition or change of service or IoT sensors. The IEEE 1451.4 standard-based or IPMI specification-based smart sensor technology supports the development of plug-and-play sensors that solve the first problem. However, there is a lack of research that requires a second problem-solving, which requires support for the plug-in of IoT sensors into remote services. To propose a solution for the integration of these two problem-solving, we present a IoT sensor platform, a service system architecture, and a service plugin protocol for the MQTT-based IIoT application environment.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.139-146
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• 2022

Wireless access technologies are emerging to enable high data rates for mobile users and novel applications that encompass both human and machine-type interactions. An essential approach to meet the rising demands on network capacity and offer high coverage for wireless users on upcoming fifth generation (5G) networks is heterogeneous networks (HetNets), which are generated by combining the installation of macro cells with a large number of densely distributed small cells Deployment in 5G architecture has several issues because to the rising complexity of network topology in 5G HetNets with many distinct base station types. Aside from the numerous benefits that dense small cell deployment delivers, it also introduces key mobility management issues such as frequent handover (HO), failures, delays and pingpong HO. This article investigates 5G HetNet mobility management in terms of radio resource control. This article also discusses the key challenges for 5G mobility management.

• Coupled systems mechanics
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• v.11 no.6
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• pp.543-556
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• 2022

Delamination of multilayered inhomogeneous beam that exhibits non-linear relaxation behavior is analyzed in the present paper. The layers are inhomogeneous in the thickness direction. The dealamination crack is located symmetrically with respect to the mid-span. The relaxation is treated by applying a non-linear stress-straintime constitutive relation. The material properties which are involved in the constitutive relation are distributed continuously along the thickness direction of the layer. The delamination is analyzed by applying the J-integral approach. A time-dependent solution to the J-integral that accounts for the non-linear relaxation behavior is derived. The delamination is studied also in terms of the time-dependent strain energy release rate. The balance of the energy is analyzed in order to obtain a non-linear time-dependent solution to the strain energy release rate. The fact that the strain energy release rate is identical with the J-integral value proves the correctness of the non-linear solutions derived in the present paper. The variation of the J-integral value with time due to the non-linear relaxation behavior is evaluated by applying the solution derived.

• Annual Conference of KIPS
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• 2010.11a
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• pp.256-259
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• 2010

본 논문에서는 오픈 아키텍처 기반의 이기종 분산 시스템에서 애플리케이션 관리 및 모니터링 시스템을 구현한다. 전투관리 시스템이나 공정관리 시스템 등과 같은 통합관리 시스템은 다양한 이기종 분산 시스템으로 구성되며 이러한 분산 환경에서 다양한 애플리케이션들이 동작하게 되는데 이들을 통제 감시하는 방법이 필요하다. 본 논문에서는 추상적인 정보모델을 이용하여 이기종 시스템들을 표현하고 이를 통해 상호의존성을 관리함으로써 다양한 애플리케이션을 효과적으로 관리하고 모니터링 할 수 있는 방안을 제시한다.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.226-240
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• 2023

This paper provides an overview of the trends and future directions in the development of anode materials for solid oxide fuel cells (SOFCs) using hydrocarbons as fuel, with the aim of enabling a decentralized energy supply. Hydrocarbons (such as natural gas and biogas) offer promising alternatives to traditional energy sources, as their use in SOFCs can help meet the growing demands for energy. We cover several types of materials, including perovskite structures, high-entropy alloys, proton-conducting ceramic materials, anode on-cell catalyst reforming layers, and anode functional layers. In addition, we review the performance and long-term stability of cells based on these anode materials and assess their potential for commercial manufacturing processes. Finally, we present a model for enhancing the applicability of fuel cell-based power generation systems to assist in the realization of the H₂ economy as the best practice for enabling distributed energy. Overall, this study highlights the potential of SOFCs to make significant progress toward a sustainable and efficient energy future.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.547-548
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• 2020

데이터의 양은 기술의 발전과 함께 크게 증가하였다. Hadoop은 빅데이터 분야에서 사용되는 대표적인 빅데이터 처리 플랫폼으로 IoT 분야에서도 사용된다. HDFS(Haddop Distributed File System)는 Hadoop의 코어 프로젝트로 블록 기반의 대용량 데이터 저장소다. 기존의 Hadoop 기반 IoT 센서 데이터 수집 환경은 HDFS를 사용한다. 그러나 HDFS의 Small File로 인한 네임노드의 과부하 문제와 한 번 Import된 데이터의 Update와 Delete를 지원하지 않는 Hadoop의 특징으로 인해 성능과 활용이 제한적이다. 본 논문에서는 기존 Hadoop 기반 IoT 센서 데이터 수집 환경의 단점을 극복하기 위해 Lambda 구조를 적용한 IoT 센서 데이터 수집 환경을 설계한다.

• Annual Conference of KIPS
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• 2023.11a
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• pp.151-153
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• 2023

Federated learning (FL)-based network intrusion detection techniques have enormous potential for securing the Industrial Internet of Things (IIoT) cybersecurity. The openness and connection of systems in smart industrial facilities can be targeted and manipulated by malicious actors, which emphasizes the significance of cybersecurity. The conventional centralized technique's drawbacks, including excessive latency, a congested network, and privacy leaks, are all addressed by the FL method. In addition, the rich data enables the training of models while combining private data from numerous participants. This research aims to create an FL-based architecture to improve cybersecurity and intrusion detection in IoT networks. In order to assess the effectiveness of the suggested approach, we have utilized well-known cybersecurity datasets along with centralized and federated machine learning models.