• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.7
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• pp.303-312
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• 2006

This paper proposes the architecture and protocol of a data communication network for the safety system in nuclear power plants. First, we establish four design criteria with respect to determinability, reliability, separation and isolation, and verification/validation. Next we construct the architecture of the safety network for the following systems: PPS (Plant Protection System), ESF-CCS (Engineered Safety Features-Component Control System) and CPCS (Core Protection Calculator System). The safety network consists of 12 sub-networks and takes the form of a hierarchical star. Among 163 communication nodes are about 1600 origin-destination (OD) pairs created on their traffic demands. The OD pairs are allowed to exchange data only during the pre-assigned time slots. Finally, the communication protocol is designed in consideration of design factors for the safety network. The design factors include a network topology of star, fiber-optic transmission media, synchronous data transfer mode, point-to-point link configuration, and a periodic transmission schedule etc. The resulting protocol is the modification of IEEE 802.15.4 (LR-WPAN) MAC combined with IEEE 802.3 (Fast Ethernet) PHY. The MAC layer of IEEE 802.15.4 is simplified by eliminating some unnecessary (unctions. Most importantly, the optional TDMA-like scheme called the guaranteed time slot (GTS) is changed to be mandatory to guarantee the periodic data transfer. The proposed protocol is formally specified using the SDL. By performing simulations and validations using Telelogic Tau SDL Suite, we find that the proposed safety protocol fits well with the characteristics and the requirements of the safety system in nuclear power plants.

• Nuclear Engineering and Technology
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• v.38 no.2
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• pp.185-194
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• 2006

Transient operations for an integral type reactor, SMART-P, have been experimentally investigated using a thermal-hydraulic integral test facility, VISTA (Experimental Verification by Integral Simulation of Transients and Accidents), in order to verify the system design and performance of the SMART-P, a pilot plant of SMART. The VISTA facility was subjected to various accident conditions such as feedwater increase and decrease, loss of coolant flow, and control rod withdrawal accidents in order to elucidate the thermal-hydraulic responses following such accidents and finally to verify the system design of the SMARTP. Full functional control logics have been implemented in the VISTA facility in order to control the required control action for an accident simulation. As one of the sensitivity tests to verify the PRHRS performance, the effects of the initial water level in the compensation tank are experimentally investigated. When the initial water level is 16%, the water is quickly drained and nitrogen gas is then introduced into the PRHR system, resulting in deterioration of the PRHRS performance. It is thus found that nitrogen ingression should be prevented to ensure stable PRHRS operation.

• Journal of the Korea Society of Computer and Information
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• v.26 no.10
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• pp.167-172
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• 2021

After the Ferry Sewol accident, public interest in marine safety has increased. However, as the marine leisure tourism population increases, the number of casualties caused by marine accidents is increasing, so marine safety education is urgently needed. Since facilities related to marine safety education in Korea are geographically biased to the west, regional imbalances in education are significant. Therefore, this study suggested solutions to the problems of developing educational contents and securing budgets and professionals by using idle facilities of the Korea Institute of Maritime and Fisheries Technology(KIMFT) located in Busan as a maritime safety education center. In addition, as a result of estimating demand using the gravity model, it was estimated that the demand would range from 150,000 to 130,000 per year. This study sufficiently proved social policy validity for policy suggestions using existing idle sites as maritime safety education centers based on objective verification methods and is expected to contribute substantially to policy promotion in the future.

• Convergence Security Journal
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• v.18 no.3
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• pp.141-148
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• 2018

The purpose of this study is to analyze the safety needs and life satisfaction of users of security system. The contents of the questionnaire consisted of "safety need, use satisfaction, life satisfaction". As a result of the analysis, Chronbach's alpha coefficient was calculated as 0.897 for safety needs, 0.888 for use satisfaction, and 0.887 for life satisfaction. The items were found to have internal consistency. In the validation of discriminant validity, both AVE and CR values were found to be 0.6 or more than the reference value of 0.8. The intuitiveness of the variables used in this study was found to be largely secured. As the hypothesis test result, the standardization factor was calculated as 0.993 for 'safety needs ⇨ use satisfaction' and 0.453 for 'use satisfaction ⇨ life satisfaction', and both hypotheses were positive. As a result of the verification, it was analyzed that the higher the user's safety needs, the higher the use satisfaction, and the higher the use satisfaction, the higher the life satisfaction.

• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.80-88
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• 2022

The Korean nuclear industry had developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code, which adopts a two-fluid, three-field model that is comprised of gas, continuous liquid and droplet fields and has the capability to simulate three-dimensional models. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for the accident management plan of a nuclear power plant was determined based on the lessons learned from the Fukushima accident. Generally, to improve the reliability of the calculation results of a safety analysis code, verification is required for the separate and integral effect experiments. Therefore, the goal of this work is to verify the calculation capability of the SPACE code for multiple failure accidents. For this purpose, an experiment was conducted to simulate a Control Element Drive Mechanism (CEDM) break with a safety injection failure using the ATLAS test facility, which is operated by Korea Atomic Energy Research Institute (KAERI). This experiment focused on the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The results of the overall system transient response using the SPACE code showed similar trends with the experimental results for parameters such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it can be concluded that the SPACE code has sufficient capability to simulate a CEDM break with a safety injection failure accident.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.60-68
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• 2024

Purpose: When designing plants and workplaces such as handling and using chemicals, a system that can automatically determine whether the design has been made in compliance with domestic safety management laws is established to shorten the review time and increase accuracy. Method: Safety design standards for chemical handling and use workplaces were investigated, and types and systems were derived that could automatically judge design errors by dividing the articles into semantic units. Result: An automatic design review method performed when designing a building was proposed, and a system that can review the safety design requirements required when designing a chemical handling business site through the development of a rule checker was proposed. After confirming whether the law is subject to application, the safety design rules are classified into semantic units through preprocessing. The classified results can be classified into four types, and the specifications, space, conditions, situations, and specific devices and facilities to reinforce safety were analyzed as representative types. It proposes a system that prepares a diagram for the safety design rule and allows it to be reviewed through the rule checker program.

• Journal of Platform Technology
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• v.11 no.6
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• pp.47-55
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• 2023

With the goal of ensuring the safety of wheelchair users, this study was conducted using finite element analysis, focusing on the development of a platform that can be used to evaluate safety during the design stage. Safety evaluation criteria for wheelchairs used in vehicles are defined in ANSI/RESNA WC19 and ISO 7176-19. Based on these standards, finite element analysis was performed to assess the sectional forces of each component of the wheelchair and sensitivity analysis was conducted based on the specifications. These results were used to derive equivalent composite loads for the wheelchair's main components, determine the necessary sectional specifications for these main components in the wheelchair design phase, and investigate the process of safety assessment verification. The study showed that member forces vary with changes in the cross-sectional values of the wheelchair frame's main components, with the front and rear lower members, as well as the rear upper and lower members, requiring the highest cross-sectional values for safety design. This study offers a proactive method for evaluating safety in the wheelchair design stage, and in future research, we plan to develop a safety evaluation platform based on these results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.284-295
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• 2012

The purpose of this study was to develop and evaluate patient safety reporting promoting strategy for nurses to improve nursing care quality. The process included three phase - construction, implementation and evaluation phase. Before the construction phase has two kinds of subcategories as analysis and verification. Analysis phase was consisted of literature review and field study, and verification was conducted by two specialist. At the construction phase, patient safety reporting system, educational materials, planning for public relation, and reward preparation were developed. After implementation during 12 weeks, we evaluated pre-post scores of satisfaction, stress of conscience, job performances. The participants were 51 nurses working for a hospitals. The program was developed and then administered to the experimental group for 12 weeks. One group pretest-posttest design was used for this study. Data were analyzed using descriptive analysis, paired t-test with the SPSS WIN 18.0 program. After the intervention, job performance scores improved significantly from 3.62 to 3.75(t=2.653, p=.009). But job stress didn't changed significantly(t=.785, p=.434). These strategy can be applied to many clinical setting that will be helpful to promote patient safety reporting for nurses.

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.256-263
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• 1998

In this paper, we propose a volume holographic fingerprint recognition system based on optical correlator for personal identification. Optical correlator has high speed and parallel processing characteristics of optics. Matched filters are recorded into a volume hologram that can store data with high density, transfer them with high speed, and select a randomly chosen data element. The multiple reference images of database are prerecorded in a photorefractive crystal in the form of Fourier transform images, simply by passing the image displayed in a spatial light modulator through a Fourier transform lens. The angular multiplexing method for multiple holograms of database can be achieved by rotating the crystal by use of a step motor. Experimental results show that the proposed system can be used for the security verification system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.199-204
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• 2006

To develop a safety-critical network in nuclear power plants that puts more stringent requirements than the competitive commercial ones do, we establish four design criteria - deterministic communication, explicit separation/isolation structure, reliability, verification & validation. According to those design criteria, the fundamental design elements are chosen as follows - a star topology, point-to-point physical link, connection-oriented link control and fixed allocation access control. After analyzing the design elements, we also build a communication architecture with TDM (Time Division Multiplexing) bus switching scheme. Finally, We develop a DDCNet (Deterministic Data Communication Network) based on the established architecture. The DDCNet is composed of 64 nodes and guarantees the transmission bandwidth of 10Mbps and the delay of 10 msec for each node. It turns out that the DDCNet satisfies the aforementioned design criteria and can be adequately utilized for our purpose.