• Current Optics and Photonics
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• v.5 no.2
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• pp.147-154
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• 2021

Microfluidic chip technology is a research focus in biology, chemistry, and medicine, for example. However, microfluidic chips are rarely applied in imaging, especially in ghost imaging. Thus in this work we propose a ghost-imaging system, in which we deploy a novel microfluidic chip modulator (MCM) constructed of double-layer zigzag micro pipelines. While in traditional situations a spatial light modulator (SLM) and supporting computers are required, we can get rid of active modulation devices and computers with this proposed scheme. The corresponding simulation analysis verifies good feasibility of the scheme, which can ensure the quality of data transmission and achieve convenient, fast ghost imaging passively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1470-1476
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• 2020

This paper describes a design of a lightweight security system-on-chip (SoC) suitable for the implementation of security protocols for IoT and mobile devices. The security SoC using Cortex-M0 as a CPU integrates hardware crypto engines including an elliptic curve cryptography (ECC) core, a SHA3 hash core, an ARIA-AES block cipher core and a true random number generator (TRNG) core. The ECC core was designed to support twenty elliptic curves over both prime field and binary field defined in the SEC2, and was based on a word-based Montgomery multiplier in which the partial product generations/additions and modular reductions are processed in a sub-pipelining manner. The H/W-S/W co-operation for elliptic curve digital signature algorithm (EC-DSA) protocol was demonstrated by implementing the security SoC on a Cyclone-5 FPGA device. The security SoC, synthesized with a 65-nm CMOS cell library, occupies 193,312 gate equivalents (GEs) and 84 kbytes of RAM.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1145-1150
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• 2020

After the Davos Forum, the recent 4th Industrial Revolution has become an area of interest to countries around the world. Among the technologies of the 4th industrial revolution, the ubiquitous computing environment requires a convergence environment of various devices, networks, and software technologies, and the RFID technology that identifies objects among the IoT technology fields is applied to all industries and has a competitive edge. Systems to which RFID technology is applied are being used in various industrial fields, especially! It is efficiently used for accurate inventory management and SCM management in the field of distribution and logistics. If the RFID system is built in a cloud-based environment, it will be possible to secure reliability in distribution management in consideration of an effective logistics management system and economic feasibility. This study is a study on the RFID system in a cloud computing environment to reduce the cost of operating or maintaining an application server to improve the economy and reliability.

• Design & Manufacturing
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• v.14 no.4
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• pp.71-77
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• 2020

Various manufacturing technologies, including over-molding and insert-injection molding, are used to produce hybrid plastics and metals. However, there are disadvantages to these technologies, as they require several steps in manufacturing and are limited to what can be reasonably achieved within the complexities of part geometry. This study aims to determine a practical approach for producing metal/plastic hybrid components by combining plastic injection molding and metal die casting to create a new hybrid metal/plastic molding process. The integrated metal/plastic hybrid injection molding process developed in this study uses the proven method of multi-component technology as a basis to combine plastic injection molding with metal die casting into one integrated process. In this study, the electrical conductivity and ampacity were verified to qualify the new process for the production of parts used in electronic devices. The electrical conductivity was measured, contacting both sides of the test sample with constant pressure, and the resistivity was measured using a micro ohmmeter. Also, the specific conductivity was subsequently calculated from the resistivity and contact surface of the conductor path. The ampacity defines the maximum amount of current a conductive path can carry before sustaining immediate or progressive deterioration. The manufactured hybrid multi-components were loaded with increasing currents, while the temperature was recorded with an infrared camera. To compare the measured infrared images, an electro-thermal simulation was conducted using commercial CAE software to predict the maximum temperature of the power loaded parts. Overall, during the injection molding process, it was demonstrated that multifunctional parts can be produced for electric and electronic applications.

• Journal of the Korea Society of Computer and Information
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• v.26 no.7
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• pp.57-64
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• 2021

In this paper, we propose and test the efficacy of an easy-to-use user location certification system for public places that relies on frequencies outside the audible range for humans. The inaudible frequencies come in signal frequency between 18-20 kHz and are generated by general audio speaker. After an individual's smart device detects the signal frequency, it sends the frequency value, user's personal ID, and user's location to a system server that certifies the user's visit location currently. The system server then saves a user visit record and categorizes it by individual. To show the usefulness of this proposed system, we developed a user visit certification application for smart devices linked to a system server. We then conducted a user visit certification experiment using the proposed system, with the result showing 99.6% accuracy. For a comparison, we then held a user visit certification experiment using a QR code, which confirmed that our proposed system performs better than QR code location certification. This proposed system can thus provide restaurants and other facilities reliable user contact tracing and electronic visitor access lists in the age of COVID-19.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.25-36
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• 2021

This paper presents a topology based on packet tracer and a five-step scenario model to make it easier for students to understand the network on which VLANs are applied. Virtual LAN (VLAN), developed as an alternative solution to the Routers that distribute broadcast traffic, is a virtual local area network that logically configured regardless of the physical network. The VLAN prevents the network performance degradation resulting from the broadcast traffic by dividing the broadcast domain so that the bandwidth can be used more efficiently. In addition, it enhances the security because on communication between the devices belonging to different VLANs is impossible. The five-step scenarios in this paper presented an efficient implementation case for students to understand and validate the various functions of VLANs through ping/telnet/tracert test and simulation, after setting up each step of programming switches and routers in the virtual network.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.70-76
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• 2021

A cylindrical microlens (CML) has been widely used as an optical element for organic light-emitting diodes (OLEDs), light diffusers, image sensors, 3D imaging, etc. To fabricate high-performance optoelectronic devices, the CML with high aspect ratio is demanded. In this work, we report on facile solution-based processes (i.e., slot-die and needle coatings) to fabricate the CML using poly(methyl methacrylate) (PMMA). It is found that compared with needle coating, slot-die coating provides the CML with lower aspect ratio due to the wide spread of solution along the hydrophilic head lip. Although needle coating provides the CML with high aspect ratio, it requires a high precision needle array module. To demonstrate that the aspect ratio of CML can be enhanced using slot-die coating, we have varied the molecular weight of PMMA. We can achieve the CML with higher aspect ratio using PMMA with lower molecular weight at a fixed viscosity because of the higher concentration of PMMA solute in the solution. We have also shown that the aspect ratio of CML can be further boosted by coating it repeatedly. With this scheme, we have fabricated the CML with the width of 252 ㎛ and the thickness of 5.95 ㎛ (aspect ratio=0.024). To visualize its light diffusion property, we have irradiated a laser beam to the CML and observed that the laser beam spreads widely in the vertical direction of the CML.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1113-1122
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• 2020

Recently, as violent crimes of crime without reason (Korea : Do not ask), women and the elderly are getting serious. In the existing system, many CCTVs are installed, but it is difficult to prevent crime due to only follow-up measures after a crime occurs. This device prevents crime through this device for incidents in shaded areas and closed spaces such as apartments and buildings. To do this, we research this technology to develop products and software. It sends an alarm signal using communication technology to a specific place where you want to receive an event of an alarm or a CCTV device operated using image analysis big data technology and convergence sensor technology for a specific target of the behavior expected to be a crime or movement. Develop the device. This development device researches and develops this device and supplies low-cost devices to consumers, which is used as a device that predicts the occurrence of crime in advance, processes it as an alarm signal in real time, and transmits it, and constitutes a standalone device and a server. Will provide the device to be connected.

• Journal of Biomedical Engineering Research
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• v.42 no.4
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• pp.175-185
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• 2021

Purpose: Vital sign are used to help assess the general physical health of a person, give clues to possible diseases, and show progress toward recovery. Researchers are using vital sign data and AI(artificial intelligence) to manage a variety of diseases and predict mortality. In order to analyze vital sign data using AI, it is important to select and extract vital sign data suitable for research purposes. Methods: We developed a method to visualize vital sign and early warning scores by processing retrospective vital sign data collected from EMR(electronic medical records) and patient monitoring devices. The vital sign data used for development were obtained using the open EMR big data MIMIC-III and the wearable patient monitoring device(CareTaker). Data processing and visualization were developed using Python. We used the development results with machine learning to process the prediction of mortality in ICU patients. Results: We calculated NEWS(National Early Warning Score) to understand the patient's condition. Vital sign data with different measurement times and frequencies were sampled at equal time intervals, and missing data were interpolated to reconstruct data. The normal and abnormal states of vital sign were visualized as color-coded graphs. Mortality prediction result with processed data and machine learning was AUC of 0.892. Conclusion: This visualization method will help researchers to easily understand a patient's vital sign status over time and extract the necessary data.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1213-1222
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• 2021

This study is a digitalization study based on ICT technology as part of the development of innovative technologies in the new energy industry as a 2050 carbon-neutral policy. It is the development of an oneM2M-based IoT server platform that can be integrated and managed in conjunction with the external interface of each energy facility. It analyzes KEPCO's e-IoT standard specifications through the Power Research Institute's 'SPIN' and develops representative standards, LWM2M and oneM gateway platforms. OneM2M secures and analyzes the recently announced standard for Release 2 instead of the existing Release 1. In addition, the e-IoT standard oneM2M platform is developed based on R2. In addition, it selects the specifications for e-IoT gateway devices that can sufficiently implement KEPCO's e-IoT standards. In addition, a technology and system for developing a high-performance gateway device that considers future scalability were proposed.