• Journal of Information Technology Services
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• v.21 no.5
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• pp.1-13
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• 2022

With the rapid development of computer technology and communication networks in modern society, human economic activities in the almost every field of our society depend on various electronic devices. The huge amount of digital data generated in these circumstances is refined by technologies such as artificial intelligence and big data, and its value has become larger and larger. However, until now, it is the reality that the digital data has not been clearly defined as an economic asset, and the institutional criteria for expressing its value are unclear. Therefore, this study organizes the definition and characteristics of digital data, and examines the matters to be considered when considering digital data in terms of accounting assets. In addition, a method that can objectively measure the value of digital data was presented as a quantitative calculation model considering the time value of profits and costs.

• Molecules and Cells
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• v.45 no.11
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• pp.771-780
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• 2022

The field of extracellular vesicles (EVs) has expanded tremendously over the last decade. The role of cell-to-cell communication in neighboring or distant cells has been increasingly ascribed to EVs generated by various cells. Initially, EVs were thought to a means of cellular debris or disposal system of unwanted cellular materials that provided an alternative to autolysis in lysosomes. Intercellular exchange of information has been considered to be achieved by well-known systems such as hormones, cytokines, and nervous networks. However, most research in this field has searched for and found evidence to support paracrine or endocrine roles of EV, which inevitably leads to a new concept that EVs are synthesized to achieve their paracrine or endocrine purposes. Here, we attempted to verify the endocrine role of EV production and their contents, such as RNAs and bioactive proteins, from the regulation of biogenesis, secretion, and action mechanisms while discussing the current technical limitations. It will also be important to discuss how blood EV concentrations are regulated as if EVs are humoral endocrine machinery.

• Journal of information and communication convergence engineering
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• v.21 no.1
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• pp.24-31
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• 2023

The solid-state drive (SSD) possesses higher input and output speeds, more resistance to physical shock, and lower latency compared with regular hard disks; hence, it is an increasingly popular storage device. However, tiny components on an internal printed circuit board (PCB) hinder the manual detection of malfunctioning components. With the rapid development of artificial intelligence technologies, automatic detection of components through convolutional neural networks (CNN) can provide a sound solution for this area. This study proposes applying the YOLOv5 model to SSD PCB component detection, which is the first step in detecting defective components. It achieves pioneering state-of-the-art results on the SSD PCB dataset. Contrast experiments are conducted with YOLOX, a neck-and-neck model with YOLOv5; evidently, YOLOv5 obtains an mAP@0.5 of 99.0%, essentially outperforming YOLOX. These experiments prove that the YOLOv5 model is effective for tiny object detection and can be used to study the second step of detecting defective components in the future.

• ETRI Journal
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• v.44 no.6
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• pp.966-976
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• 2022

Optical wireless communication, or free space optics, is a promising solution for backhauls in sixth-generation mobile systems. However, the susceptibility of optical links to weather conditions has led to FSO links being furnished with radio frequency (RF) backups. These Hybrid FSO/RF systems provide enhanced link availability but lead to RF resource wastage. Cognitive radio technology, in contrast, is well known for its optimal use of RF resources and may be combined with an FSO link to create a Cognitive Hybrid FSO/RF system. This work uses such a system to analyze a configuration for a mobile backhaul in sixth-generation mobile systems. This configuration can seamlessly coexist with established large scale RF cellular networks. The performance of this configuration is analyzed with respect to outage probability and average bit error by considering the impact of optical channel turbulence, misalignment loss, RF interference, and noise. Mathematical closed-form expressions are verified by simulations.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.40-50
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• 2023

Blockchain is a technology designed to prevent tampering with digital documents or information, safeguarding transaction data and managing it in a structured manner. This proves beneficial in addressing issues of trust and data protection in B2B, B2C, and C2B transactions. Blockchain finds utility not only in financial transactions but also across diverse industrial sectors. This study outlines significant cases and responses that jeopardize the security of blockchain networks and cryptocurrency technology. Additionally, it analyzes safety and risk factors related to blockchain and proposes effective testing methods to preemptively counter these challenges. Furthermore, this study presents key security evaluation metrics for blockchain to ensure a balanced assessment. Additionally, it provides evaluation methods and various test case models for validating the security of blockchain and cryptocurrency transaction services, making them easily applicable to the testing process.

• Journal of information and communication convergence engineering
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• v.21 no.3
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• pp.185-191
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• 2023

The Internet of Things (IoT) can be defined as the connection of devices, sensors, and actors via the Internet to a single network to provide services to end-users. Owing to the flexibility and simplicity of IoT devices, which impart convenience to end-users, the demand for these devices has increased significantly in the last decade. To make these systems more scalable, achieve a larger number of connected devices, and achieve greater economic success, it is vital to develop them by considering parameters such as security, cost, bandwidth, data rate, and power consumption. This study aims to improve energy efficiency and prolong the lifetime of IoT networks by proposing a new approach called the constrained application protocol CoAP45. This approach reduces the number of updates to the CoAP server using a centralized resource. The simulation results show that the proposed approach outperforms all existing protocols.

• Journal of information and communication convergence engineering
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• v.21 no.3
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• pp.198-207
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• 2023

Responding to changes in artificial intelligence models and the data environment is crucial for increasing data-learning accuracy and inference stability of industrial applications. A learning model that is overfitted to specific training data leads to poor learning performance and a deterioration in flexibility. Therefore, an early stopping technique is used to stop learning at an appropriate time. However, this technique does not consider the homogeneity and independence of the data collected by heterogeneous nodes in a differential network environment, thus resulting in low learning accuracy and degradation of system performance. In this study, the generalization performance of neural networks is maximized, whereas the effect of the homogeneity of datasets is minimized by achieving an accuracy of 99.7%. This corresponds to a decrease in delay time by a factor of 2.33 and improvement in performance by a factor of 2.5 compared with the conventional method.

• Annual Conference of KIPS
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• 2010.11a
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• pp.975-978
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• 2010

그룹통신에서의 작업자 간에 긴밀한 통신을 필요로 하는 경우에 기존의 무전기나 주파수 공용통신은 음성 품질이 매우 열악하여 통신 신뢰성이 매우 낮다. 이러한 문제를 해결하기 위해 그룹통신에서 VoIP를 활용하는 것이 요구된다. VoIP를 이용할 경우 20ms정도의 짧은 주기로 인하여 패킷마다의 헤더로 인한 오버헤드가 발생하는데 이를 해결하기 위해 그룹통신에서의 패킷번들링이 요구된다. 따라서 본 연구에서는 패킷번들링을 적용한 상태에서 VoIP를 이용한 그룹통신 성능분석을 하였다.

• Annual Conference of KIPS
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• 2009.11a
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• pp.525-526
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• 2009

Due to the limitation of battery life time, energy is one of the most crucial issues for wireless sensor networks. Thus this paper proposes an energy efficient duty cycle scheme to conserve energy mostly. To handle the large varieties of data (i.e., both low and high traffic load) the proposed duty cycle scheme ensures a fair access period (FAP) and a prioritized access period (PAP). The idea presented in this paper able to reduce the collision probability and energy consumption. Finally simulation outputs have demonstrated the effectiveness of the proposed duty cycle task and showed a noticeable performance in terms of energy usage.

• Annual Conference of KIPS
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• 2009.04a
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• pp.1352-1355
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• 2009

TCP에서 사용되는 혼잡제어(Congestion control)는 많은 이점이 있지만 그에 상응하는 단점이 존재한다. 가장 널리 사용되고 있는 TCP-Reno는 혼잡이 발생되면 혼잡 윈도우(Congestion Window)크기를 절반으로 줄이고 빠른 회복(fast recovery), 빠른 재전송(fast transmit)을 수행한다. 하지만 네트워크가 고속 네트워크로 접어들면서 효율적인 측면에서 이러한 기법들을 적용하기에는 문제가 따른다. 현재 사용되고 있는 TCP는 혼잡이 발생하면 선형적으로 점진적으로 증가 하기 때문에 많은 대역폭을 지원하는 고속 네트워크에서는 이러한 TCP의 혼잡 제어가 오히려 비 효율적이다. 본 논문에서는 이러한 문제점을 해결하기 위해 혼잡 윈도우 증가율을 추가한 혼잡제어 기법인 TCP-FBA(Fast Bandwidth Acquisition)를 제안한다.