• Knowledge Management Research
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• v.22 no.3
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• pp.1-16
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• 2021

For the effective responsiveness toward Management Evaluation System of Public Institutions and continuous development as a public corporation, internal performance management is essential. In this study, the effect of employees' perceptions on the effectiveness and acceptability of the internal performance evaluation system on organizational commitment was tested, and we attempted to find implications for efficient performance management. For this purpose, we obtained valid responses from 208 members of A corporation and the hypotheses were verified through multiple regression analysis. As a result of the analysis, 'performance evaluation effectiveness' and 'performance evaluation acceptability' for internal performance evaluation had positive effects on 'organizational commitment'; however, the effect of 'differential performance compensation' on 'organizational commitment' was not significant. Also, among the control variables, 'age' and 'job group' were found to have a negative (-) effect on 'organizational commitment'. To derive more generalized conclusion, other researches using bigger samples are needed.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.105-113
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• 2019

The purpose of this study is to analyze cyber security risk modeling of critical infrastructure, draw out limitations and improvement measures. This paper analyzed cyber security risk modeling of national critical infrastructure like as electricity sector, nuclear power plant, SCADA. This paper analyzed the 26 precedent research cases of risk modeling in electricity sector, nuclear power plant, SCADA. The latest Critical Infrastructure is digitalized and has a windows operating system. Critical Infrastructure should be operated at all times, it is not possible to patch a vulnerability even though find vulnerability. This paper suggest the advanced cyber security modeling characteristic during the life cycle of the critical infrastructure and can be prevented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.58-67
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• 2019

The low-voltage connection box used as a low-voltage transmission line of KEPCO is intended to branch or connect to an underground line. In comparison with the utility considering the aesthetics of the distance, and safety measures are needed. In this paper, temperature and humidity, $CO_2$, water level, acceleration, and vibration sensor are installed inside the underground low voltage handhole, and the sensor data is transmitted to the ground using the Zigbee module. Antenna (Bolted Antenna) for communication with the ground was proposed and the data reception through it was confirmed. In the LF mode and the HEX mode, the transmitted data was confirmed to be a perfect reception success rate. In the case of the bolted antenna, the difference between the ground state and the underwater state was observed as a result of the experiment in the environmental environment. However, It was judged that reception sensitivity was sufficient for communication. The received data could be confirmed through PC based GUI.

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.35-44
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• 2019

The purpose of this study is to find out quantitative vulnerability assessment about COTS(Commercial Off The Shelf) O/S based I&C System. This paper analyzed vulnerability's lifecycle and it's impact. this paper is to develop a quantitative assessment of overall cyber security risks and vulnerabilities I&C System by studying the vulnerability analysis and prediction method. The probabilistic vulnerability assessment method proposed in this study suggests a modeling method that enables setting priority of patches, threshold setting of vulnerable size, and attack path in a commercial OS-based measurement control system that is difficult to patch an immediate vulnerability.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.643-652
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• 2021

Accidents or faults in the transmission and distribution system are never completely avoidable, and short-circuit and earth faults are occurs despite the efforts of the TSO and DSO. Recently, the connection to the transmission and distribution system of large-capacity new and renewable distributed power has increased rapidly and has various effects on the operation of the system. In order to minimize this, connection standards such as FRT (Fault-Ride-Through) have been established to provide wind turbines or solar inverters. In the event of a major faults of the power system, the operation support shall be provided so that the operator can stably operate the system by smoothly performing connection maintenance or rapid system separation. In this paper, in order to appropriately determine whether the FRT condition, which is the grid connection criterion for a representative DERs, is sufficient, a detection system using a PMU (Phasor Measurement Unit) that measures a synchro-phasors was designed and deployment and a system accident due to a generator step-out to analyze and evaluate the proposed system based on the case.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.653-660
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• 2021

Renewable energy resources are rapidly becoming an integral part of electricity generation portfolios around the world due to declining costs, government subsidies, and corporate sustainability goal. Interacting wind, solar, and load forecast errors can create significant unpredictable impacts on the distribution system, feeder congestion, voltage standard and reactive power stability margins. These impacts will be increasing with the increasing penetration levels of variable renewable generation in the power systems. There is a limit to the maximum amount of renewable energy sources that can be connected in a distribution feeder by the connection rule of transmission & distribution facility in Korea. This study represents the decision plans of hosting capacity for distribution feeders without the need for significant upgrades to the existing transmission infrastructure. Especially, the paper suggests and discusses the hosting capacity standard of feeder cables and minimum load calculation of distribution feeders.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.27-33
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• 2011

In general, the shear strength of a clay specimen under the direct shear test and the triaxial compression test increases with an increase in the shear rate. This study investigates the effects of shear rate and silt content on the stress-strain behavior of remolded Gwangyang clay, by changing the shear rate and the silt content. Based on the results of the triaxial compression tests, the equi-strain line of remolded Gwangyang clay shows initially positive slope and then becomes flat at certain strain level. As the strain level where the equistrain becomes flat is different depending on the soil with different silt contents, this can be considered as the inherent property of soil.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.566-574
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• 2011

Coal gasifier is a key component for achieving high efficiency in integrated gasification combined cycle and indirect coal liquefaction. Although there have been several successful coal gasifiers that were commercially proven, many different design configurations are still possible for a simple and reliable gasifier operation. Four different gasifier design concepts of dry-feeding were compared in terms of residence time, exit syngas temperature and syngas composition. First, cold-flow simulation was applied to pre-select the configuration concepts, and the hot-flow simulation including chemical reactions was performed to compare the concepts at more actual gasifier operating conditions. There are many limitations in applying CFD method in gasifier design, particularly in estimating slag behavior and slag-tap design. However, the CFD analysis proved to be useful in comparing the widely different gasifier design concepts as a pre-selection tool.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1141-1149
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• 2020

Most of the industrial control network is an independent closed network, which is operated for a long time after installation, and thus the OS is not updated, so security threats increase and security vulnerabilities exist. The zero-day attack defense must be applied with the latest patch, but in a large-scale industrial network, it requires a higher level of real-time and non-disruptive operation due to the direct handling of physical devices, so a step-by-step approach is required to apply it to a live system. In order to solve this problem, utility-specific patch impact assessment is required for reliable patch application. In this paper, we propose a method to test and safely install the patch using the regression analysis technique and show the proven results. As a patch impact evaluation methodology, the maximum allowance for determining the safety of a patch was derived by classifying test types based on system-specific functions, performance, and behavior before and after applying the patch. Finally, we report the results of case studies applied directly to industrial control networks, the OS patch has been updated while ensuring 99.99% availability.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.815-824
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• 2022

The growing integration of intermittent renewable sources like offshore wind energy increases the need for transferring electric energy over long distances, which may include sea crossings. One of the solutions available for bulk electric power transmission across large distances encompassing wide and deep sea is using HVDC submarine power cables. However, there are no standards or research related to the calculation of the continuous allowable current with various ocean conditions of a DC power cable that does not have an alternating magnetic field. In this study, assuming the typical two types of subsea cable models and two areas of the south coast and the west coast marine conditions, a continuous allowable current simulation of DC cables was performed. As a simulation result, the DC cable continuous allowable current find out the gradient reduction characteristics based on subsea base depth.