• Journal of Internet of Things and Convergence
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• v.7 no.1
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• pp.9-19
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• 2021

The data mining design incorporated with big data based cloud computing system is investigated for the nuclear terrorism prevention where the conventional physical protection system (PPS) is modified. The networking of terror related bodies is modeled by simulation study for nuclear forensic incidents. It is needed for the government to detect the terrorism and any attempts to attack to innocent people without illegal tapping. Although the mathematical algorithm of the study can't give the exact result of the terror incident, the potential possibility could be obtained by the simulations. The result shows the shape oscillation by time. In addition, the integration of the frequency of each value can show the degree of the transitions of the results. The value increases to -2.61741 in 63.125th hour. So, the terror possibility is highest in later time.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.689-699
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• 2021

The spread of the COVID-19 pandemic has been increasing non-face-to-face activities; as a result, this has resulted in the number of individuals obtaining medical information from the websites and mobile contents of medical institutions increasing. The study conducted the structural equation modeling to test hypotheses; as a result, all sub-factors of e-service quality of small medical clinic websites and mobile contents, usability, security, responsiveness, design, and information, had a significant positive effect on relationship quality, and relationship quality had a significant positive effect on e-Loyalty. Moreover, the structural equation model showed a good model fit, χ²/df of 2.021, NFI of .954, TLI of .969, CFI of .976, RMSEA of .046. Future research is suggested to study relationship quality by developing a system able to quickly and accurately respond to websites and mobile contents users; furthermore, improving e-service quality and relationship quality is likely to strengthen e-loyalty.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.81-98
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• 2020

Purpose - This study aims to examine the relationship between Chinese employees' collectivism orientation and organizational commitment and interpersonal helping behavior and verify the differences of such relationships between new and the previous generation of employees. Design/methodology/approach - The 262 Chinese employees participated in self-reported survey through online platform. The confirmatory factor analysis and the hierarchical regression analysis were performed to test hypotheses. Findings - We found that Chinese employees' collectivism orientation positively influenced their organizational commitment and interpersonal helping behavior. Regarding the moderating role of generation, our result revealed that while the positive relationship between collectivism orientation and organizational commitment was significant for previous generation of employees, such relationship was not valid for new generation employees. However, there was no significant generational difference in the relationship between collectivism orientation and interpersonal helping behavior. Research implications or Originality - Considering that there have been relatively few empirical studies examining the interaction between employees' cultural characteristic and generations, this study contributes to demonstrate that the positive influence of Chinese employees' collectivism orientation on organizational commitment vary depending on Chinese generations. In addition, this study provides implications that organizational leaders in China should understand that the generational difference can influence how employees' collectivism orientation leads to their attitudes towards organizations and need to establish human resource management system by reflecting generational difference.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1609-1617
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• 2019

Described in this paper is a design of hardware accelerator for implementing public-key cryptographic protocols (PKCPs) based on Elliptic Curve Cryptography (ECC) and RSA. It supports five elliptic curves (ECs) over GF(p) and three key lengths of RSA that are defined by NIST standard. It was designed to support four point operations over ECs and six modular arithmetic operations, making it suitable for hardware implementation of ECC- and RSA-based PKCPs. In order to achieve small-area implementation, a finite field arithmetic circuit was designed with 32-bit data-path, and it adopted word-based Montgomery multiplication algorithm, the Jacobian coordinate system for EC point operations, and the Fermat's little theorem for modular multiplicative inverse. The hardware operation was verified with FPGA device by implementing EC-DH key exchange protocol and RSA operations. It occupied 20,800 gate equivalents and 28 kbits of RAM at 50 MHz clock frequency with 180-nm CMOS cell library, and 1,503 slices and 2 BRAMs in Virtex-5 FPGA device.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.802-808
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• 2020

The IoT(Internet of Things) is based on the development of sensor technology and high-speed communication infrastructure, and the number of IoT connected to the network is increasing more than the number of people, and the increase is also very fast. In the field of defense, IoT is being deployed in various fields such as operations, military, base defense, and informatization, and the need is also increasing. Unlike the existing PC/server information protection system, cyber threats are also increasing as IoT sensors, which are vulnerable to information protection, are increasing in the network, so it is necessary to study the platform to protect the defense information and communication network. we investigated the case of connecting wired and wireless IoT to the defense network, and presented an efficient interlocking design method of the IoT integrated independent network with enhanced security by minimizing the contact point with the defense network.

• Design & Manufacturing
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• v.15 no.1
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• pp.26-31
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• 2021

As the aging ages, the disease also increases, and the development of AI technology and X-ray equipment used to treat patients' diseases is also progressing a lot. X-ray tube converts only 1% of electron energy into X-ray and 99% into thermal energy. Therefore, when the cooling time of the anode and the X-ray tube are frequently used in large hospitals, the amount of X-ray emission increases due to temperature rise, the image quality deteriorates due to the difference in X-ray dose, and the lifespan of the overheated X-ray tube may be shortened. Therefore, in this study, temperature rise and cooling time of 60kW, 75kW, and 90kW of X-ray tube anode input power were studied. In the X-ray Tube One shot 0.1s, the section where the temperature rises fastest is 0.03s from 0s, and it is judged that the temperature has risen by more than 50%. The section in which the temperature drop changes most rapidly at 20 seconds of cooling time for the X-ray tube is 0.1 seconds to 0.2 seconds, and it is judged that a high temperature drop of about 65% or more has occurred. After 20 seconds of cooling time from 0 seconds to 0.1 seconds of the X-ray tube, the temperature is expected to rise by more than 3.7% from the beginning. In particular, since 90kW can be damaged by thermal shock at high temperatures, it is necessary to increase the surface area of the anode or to require an efficient cooling system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.440-448
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• 2021

This paper presents problems of network technology in smart grid and implements a blockchain-based LoRa multi-hop network to solve them. Since some smart grid applications are operated in harsh environments, it is difficult to establish communication infrastructure. We propose a LoRa network with multi-hop using the Flooding routing protocol. Smart grid environment composes an independent network using various power grid protocols depending on the application. Since this has a problem that an independent infrastructure must be established for each network, a single gateway device supports multiple power grid protocols to implement a method for network integration. Lastly, the author applied Hyperledger-based blockchain to the LoRa network to ensure the integrity of data in a smart grid environment, and strengthened security by physically distributing it. After constructing the three suggestions on the actual test bed, we confirmed that the network operates normally through experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.771-780
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• 2021

The space Debris laser ranging system is called to be a definite type of satellite laser ranging system that measures the distance to satellites. It is a system that performs POD (Precise Orbit Determination) by measuring time of flight by firing a laser. Distance precision can be measured in mm-level units, and it is the most precise system among existing systems. Currently, KASI has built SLR in Sejong and Geochang, and utilized SLR data to verify the precise orbits of the STSAT-2C and KOMASAT-5. In recent years, due to the fall or collision of space debris, its satellites have been threatened, and in terms of security, laser tracking of space objects is receiving great interest in order to protect their own space assets and protect the safety of the people. In this paper, a 1.5m-class main mirror was applied for the system design of a multipurpose laser tracking system that considers satellite laser ranging and space object laser tracking. System preliminary performance analysis was performed based on Link Budget analysis considering specifications of major components.

• New & Renewable Energy
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• v.18 no.2
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• pp.73-81
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• 2022

This study was aimed at designing a condenser, as a component of the organic Rankine cycle system for ships. The condenser was manufactured through press molding to achieve a bent shape to enhance the heat transfer performance, considering the shape of the heat transfer plate used in a brazing plate heat exchanger. The heat transfer plate was made of copper-nickel alloy. The required heat transfer rate for the condenser was 110 kW, and the maximum number of layers was set as 25, considering the characteristics of high-temperature brazing. Computational fluid dynamics techniques were used to perform the thermal fluid analysis, based on the ANSYS CFX (v.18.1) commercial program. The heat transfer rate of the condenser was 4.96 kW for one layer (width and length of 0.224 and 0.7 m, respectively) of the heat transfer exchanger. The fin efficiency pertaining to the heat transfer plate was approximately 20%. The heat flow analysis for one layer of the heat exchanger plate indicated that the condenser with 25 layers of heat transfer plates could achieve a heat transfer rate of 110 kW.

• Journal of Platform Technology
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• v.9 no.4
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• pp.32-41
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• 2021

The EU enacted a law strongly regulating the GDPR to protect the privacy of its citizens on 25 May 2018. Compliance with GDPR is an essential prerequisite for companies to enter the European market in the global economic era. In this paper, Step-by-step measures have been defined to conclude DPA agreements for the appropriate level of protection against EU personal data transfer. To explore the benefits and expected effects of determining appropriateness at the government level. As a result, enterprises benefit from simplifying processes, reducing time, and reducing costs when entering the EU. Government-level support in response to personal data breach and communication with the EU Commission will have a positive impact, However, even after the adequacy decision, the entity continues to need activities to secure personal data through compliance with GDPR principles and obligations. Major operations of companies that comply with GDPR are also maintained as important tasks that must be observed in most cases except for the Data Protection Agreement.