• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.197-205
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• 2022

The Cyber Physical System(CPS) is an important concept in achieving SMSs(Smart Manufacturing Systems). Generally, CPS consists of physical and virtual elements. The former involves manufacturing devices in the field space, whereas the latter includes the technologies such as network, data collection and analysis, security, and monitoring and control technologies in the cyber space. Currently, all these elements are being integrated for achieving SMSs in which we can control and analyze various kinds of producing and diagnostic issues in the cyber space without the need for human intervention. In this study, we focus on implementing a production equipment monitoring system related to building a SMS. First, we describe the development of a fog-based gateway system that links physical manufacturing devices with virtual elements. This system also interacts with the cloud server in a multimedia network environment. Second, we explain the proposed network infrastructure to implement a monitoring system operating on a cloud server. Then, we discuss our monitoring applications, and explain the experience of how to apply the ML(Machine Learning) method for predictive diagnostics.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.3
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• pp.109-116
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• 2023

This paper presents a network-based automation system for the detection of metallic objects in food and livestock. A metal detector is a core equipment used for the inspection required by HACCP. Since the existing metal detectors are manufactured as a single-body equipment, it is difficult to take into account various user requirements for the system. In order to overcome the drawback, this study presents a network-based automation system for metal detector utilizing an industrial fieldbus and modular components. The proposed system can effectively consider the various customer requirements and control schemes. The proposed system can also achieve the improvement in speed and success rate of detecting metallic objects. The effectiveness of the proposed system is demonstrated through a various experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.64-66
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• 2023

Low Earth Orbit(LEO) Non-Terrestrial-Network(NTN) 은 위성을 사용하여 통신 서비스를 제공하지 못하는 도시 이외의 산간, 바다, 항공기 또는 외진 지역에 통신 서비스를 제공하는 모델이다. Terrestrial Network(TN) 핸드오버에서 사용되는 Measurement-Based Triggering(MHT)의 경우 User Equipment(UE)에서 측정된 값을 기반으로 Measurement Report를 전달한다. 그러나 NTN 환경에서의 HO triggering은 TN 과는 달리 장거리 통신을 요구하고 위성이 빠른 속도로 이동함에 따라 MHT에 사용되는 지표들을 대체할 방법이 필요하다. 이 논문에서는 측정 유효성을 대체할 수 있는 지표로 UE와 셀 중심 간의 거리 및 고도 각을 활용하여 HO triggering을 예측하는 시스템을 제안한다. 제안한 예측 시스템은 핸드오버 triggering 예측에 대해 우수한 성능을 보였으며 좋은 측정 결과를 얻을 수 있었다.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.37-42
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• 2018

Recently, there have been many studies on the IoT environment in which the sensors attached to the equipment automatically transmit and process the site information in real time through the network to control the equipment. The core of such a system is a network for data transmission and reception, and a wired network with wide transmission distance is a priority. However, in the case of a wired network, there is a problem that the time and cost consumed to configure the communication is higher than that of the wireless. In this paper, we propose LPWA - based wireless data transmission system using LPWA and BLE communication to solve this problem. The proposed system collects data from equipment through BLE and transmits data to the server using LPWA. Experimental results show that the spreading factor of maximum length of LPWA is 8, and the minimum length is 9.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2512-2520
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• 1997

ITU-T Q.2931 and ATM Forum UNI 3.1 lead the standardization of signaling functions for the call/connection control at B-ISDN UNI. The one is applicable to the system in the public network, which provides the point-to-point call/connection control. The other is applicable to configure ATM private network mainly related with various terminal equipments. Domestic B-ISDN developers have developed ATM switches and B-NTs as network equipment, and B-TA as a terminal equipment. But many kinds of terminal-equipments are needed to provide various services in B-ISDN. If the public network can accommodate the terminal-equipments of UNI 3.1, it's very effective to accommodate manu kinds of terminal-equipments. Therefore, this paper identifies the problems that can be occurred on the signaling procedure, when B-ISDN the public network is connected to the UNI 3.1 terminal-equipment, and provides good alternatives that can handle this kind of call/connection well.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.239-240
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• 2012

With advancements in semiconductor device technologies, manufacturing processes are getting more complex and it became more difficult to maintain tighter process control. As the number of processing step increased for fabricating complex chip structure, potential fault inducing factors are prevail and their allowable margins are continuously reduced. Therefore, one of the key to success in semiconductor manufacturing is highly accurate and fast fault detection and classification at each stage to reduce any undesired variation and identify the cause of the fault. Sensors in the equipment are used to monitor the state of the process. The idea is that whenever there is a fault in the process, it appears as some variation in the output from any of the sensors monitoring the process. These sensors may refer to information about pressure, RF power or gas flow and etc. in the equipment. By relating the data from these sensors to the process condition, any abnormality in the process can be identified, but it still holds some degree of certainty. Our hypothesis in this research is to capture the features of equipment condition data from healthy process library. We can use the health data as a reference for upcoming processes and this is made possible by mathematically modeling of the acquired data. In this work we demonstrate the use of recurrent neural network (RNN) has been used. RNN is a dynamic neural network that makes the output as a function of previous inputs. In our case we have etch equipment tool set data, consisting of 22 parameters and 9 runs. This data was first synchronized using the Dynamic Time Warping (DTW) algorithm. The synchronized data from the sensors in the form of time series is then provided to RNN which trains and restructures itself according to the input and then predicts a value, one step ahead in time, which depends on the past values of data. Eight runs of process data were used to train the network, while in order to check the performance of the network, one run was used as a test input. Next, a mean squared error based probability generating function was used to assign probability of fault in each parameter by comparing the predicted and actual values of the data. In the future we will make use of the Bayesian Networks to classify the detected faults. Bayesian Networks use directed acyclic graphs that relate different parameters through their conditional dependencies in order to find inference among them. The relationships between parameters from the data will be used to generate the structure of Bayesian Network and then posterior probability of different faults will be calculated using inference algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.65-67
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• 2013

The recent high-performance network equipment is required, and also require high network bandwidth utilization. It is a trend to develop increasingly using multi-core processors for high-performance network servers. Propose a method to improve the performance of the network sub-system, considering the characteristics of multi-core as a way to improve these high-performance and high network throughput. In this paper, we confirm through experiments on how to improve the communication performance, optimize performance and take full advantage of multi-core by Network communication process to improve the performance of the multi-core processor architecture, the process of concentration, the overhead for each core, based on network traffic according to the interrupt affinity in this process to determine the optimal core to give. The experiments were implemented in the Linux kernel, and experiments to improve the network throughput up to 30%, bringing reduces the Linux communication process to improve the performance of the processor overhead of up to 10%.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.321-326
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• 2021

Wireless communication is a core technology constituting the Internet of Things (IoT), but there is no suitable educational equipment to learn various wireless communication technologies used in the Internet of Things through practice. This paper deals with the development of advanced education and training equipment that can perform various IoT wireless communication practices. It uses an Arduino mega board as a device to control various sensors. As wireless network technologies to send and receive the sensing date wirelessly, it makes use of RFID/NFC and Bluetooth among WPAN technologies, WiFi among WLAN technologies and LoRa and 2.4GHz wireless transceiver among WWAN technologies. In addition, GPS, infrared communication, I2C communication, and SPI communication are organized so that various IoT wireless communication technologies can be learned through practice. In addition, since the educational equipment developed in this paper is equipped with two devices, it is designed to perform transmission and reception experiments for wireless network technology within the equipment.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.6
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• pp.7-20
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• 2017

The advancement of cloud and big data and the considerable growth of traffic have increased the complexity and problems in the management inefficiency of existing networks. The software-defined networking (SDN) environment has been developed to solve this problem. SDN enables us to control network equipment through programming by separating the transmission and control functions of the equipment. Accordingly, several studies have been conducted to improve the performance of SDN controllers, such as the method of connecting existing legacy equipment with SDN, the packet management method for efficient data communication, and the method of distributing controller load in a centralized architecture. However, there is insufficient research on the control of SDN in terms of the quality of network-using applications. To support the establishment and change of the routing paths that meet the required network service quality, we require a mechanism to identify network requirements based on a contract for application network service quality and to collect information about the current network status and identify the violations of network service quality. This study proposes a method of identifying the quality violations of network paths through ontology to ensure the network service quality of applications and provide efficient services in an SDN environment.

• International Journal of Railway
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• v.2 no.3
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• pp.107-112
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• 2009

Research projects of SNCF aim at reducing the costs of infrastructure possessions and improving the operational equipment availability and safety. This permanent search for a better regularity led the SNCF to analyse the maintenance approach of signalling equipment in detail. Until now, it was commonly acknowledged that signalling equipment, which consists of many electronic devices, is not subject to aging. In this study, a Weibull lifetime model, able to describe an aging phenomenon, is used and it can be shown that the deterioration is statistically significant. The validity of the model is tested. We also analyse the influence of environmental covariates. We simulate different scenarios in order to investigate the impact of several maintenance strategies as well as on future maintenance costs, on the amount of components to replace based on the mean age of the network. It can be shown that in most cases a systematic replacement strategy offers the best solution.