• Journal of Institute of Control, Robotics and Systems
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• v.22 no.4
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• pp.276-280
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• 2016

Due to the increasing interest in safety and consistent product quality over a past few decades, demand for effective quality monitoring and safe operation in the modern industry has propelled research into statistical based fault detection and diagnosis methods. This paper describes the application of Hotelling $T^2$ index based Principal Component Analysis (PCA) method for fault detection and diagnosis in industrial processes. Multivariate statistical process control techniques are now widely used for performance monitoring and fault detection. Conventional methods such as PCA are suitable only for steady state processes. These conventional projection methods causes false alarms or missing data for the systems with transient values of processes. These issues significantly compromise the reliability of the monitoring systems. In this paper, a reliable method is used to overcome false alarms occur due to varying process conditions and missing data problems in transient states. This monitoring method is implemented and validated experimentally along with matlab. Experimental results proved the credibility of this fault detection method for both the steady state and transient operations.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.199-208
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• 2015

Biologics and medical devices manufactured with bovine-derived raw materials have the risk of viral contamination. Therefore, viral validation study is essential to ensure the safety of the products. Bovine adenovirus type-1 (BAdV-1) is one of the common bovine viral pathogens. For quantitative detection of BAdV-1 during the manufacture of biologics and medical devices, a TaqMan probe real-time PCR method was developed. Specific primers and TaqMan probe for amplifying and detecting BAdV-1 DNA were designed. Specificity, limit of detection (LOD), and robustness of the method was validated according to international guideline on the validation of nucleic acid amplification tests for the pathogen detection. The sensitivity of the assay was found to be $7.44{\times}10^1\;TCID_{50}/ml$. The real-time PCR method was reproducible, very specific to BAdV-1, and robust. Moreover, the method was successfully applied to the validation of Chinese Hamster Ovary (CHO)-K1 cells artificially infected with BAdV-1, a commercial CHO master bank, and bovine type 1 collagen. The overall results indicate that this rapid, specific, sensitive, and robust assay can be reliably used for quantitative detection of BAdV-1 contamination during the manufacture of biologics and medical devices using bovine-derived raw materials.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.1-21
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• 2020

The domestic abandoned mines are generating subsidence and it is difficult to predict this subsidence and evaluate the risk. The study of the subsidence risk evaluation using the existing numerical analysis only applies the integrative property to the geological structure and ground condition, and analyzes the goaf peripheral plastic domain. Also, there is a realistic limit that only restricted materials can be apprehended in securing the input information, which leads to the low reliability of the numerical analysis result. In this study, 2-dimensional modeling was performed by applying the field geological structure and ground information targeting abandoned mine where the subsidence occurred. Also, the analysis model was revised by repeating the numerical analysis for the difference between the real subsidence ground information and the analysis result to be minimized by modifying the ground property. This revision was automated by applying the optimization technique and the gradational optimal design method dividing multiple ground properties was developed.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.86-95
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• 2006

Brillouin backscatter is a type of reflection that occurs when light is shone into an optical fibre. Brillouin reflections are very sensitive to changes in the fibre arising from external effects, such as temperature, strain and pressure. We report here several case studies on the measurement of strain using Brillouin reflections. A mechanical bending test of an I beam, deployed with both fiber optic sensors and conventional strain gauge rosettes, was performed with the aim of evaluating: (1) the capability and technical limit of the DTSS technology for strain profile sensing; (2) the reliability of strain measurement using fiber optic sensor. The average values of strains obtained from both DTSS and strain gauges (corresponding to the deflection of I beam) showed a linear relationship and an excellent one-to-one match. A practical application of DTSS technology as an early warning system for land sliding or subsidence was examined through a field test at a hillside. Extremely strong, lightweight, rugged, survivable tight-buffered cables, designed for optimal strain transfer to the fibre, were used and clamped on the subsurface at a depth of about 50cm. It was proved that DTSS measurements could detect the exact position and the progress of strain changes induced by land sliding and subsidence. We also carried out the first ever distributed dynamic strain measurement (10Hz) on the Korean Train eXpress(KTX) railway track in Daejeon, Korea. The aim was to analyse the integrity of a section of track that had recently been repaired. The Sensornet DTSS was used to monitor this 85m section of track while a KTX train passed over. In the repaired section the strain increases to levels of 90 microstrain, whereas in the section of regular track the strain is in the region of 30-50 microstrain. The results were excellent since they demonstrate that the DTSS is able to measure small, dynamic changes in strain in rails during normal operating conditions. The current 10km range of the DTSS creates a potential to monitor the integrity of large lengths of track, and especially higher risk sections such as bridges, repaired track and areas at risk of subsidence.

• Fire Science and Engineering
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• v.34 no.1
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• pp.11-17
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• 2020

As performance-based design (PBD) has a direct impact on evacuation safety assessments, designing fire scenarios based on real fire tests is essential. To improve the reliability of the PBD for fire safety in multiplexes, information on fire behavior, such as heat release rate (HRR) and fire spread rate, are provided in this study by conducting a standard fabric flammability test. To this end, several chairs were arranged in a pattern that resembled a theater-style seating. The peak HRR and heating value per unit mass for each chair ranged from 415 kW to 988 kW and 15.2 MJ/kg to 23.8 MJ/kg, respectively. The heating values per unit mass of the new and old chairs were 23.6 MJ/kg and 16.7 MJ/kg, respectively. As the quantity of plastic and cushioning materials in the new chairs was more than that of the old ones, the new chairs were more vulnerable to fire hazards. Furthermore, when the chairs were arranged in a line, the fire spread rate was observed to be 0.39-0.42 m/min, regardless of the ignition location. Finally, a fire growth curve showing the peak HRR and fire spread rate was also demonstrated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.113-119
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• 2014

Recently, R.O.K. Navy is increasing re-usability of design data and application of M&S(Modeling and Simulation) through the establishment of collaborative product development environment focused on Naval Ship Product Model(NSPM). As a result, the reliability of the result of design is getting better, and furthermore, a study to improve quality of construction through simulation of production/operation is in progress. Accordingly, the database construction of design data and the DB(Database) quality become important, but there was not research related to those or it was just initial state. This paper conducted research about system of the quality verification process of shape elements which compose NSPM based on the quality verification guideline of NSPM as the result of the precedent study. The hull surface was limited as verification object. The study to verify two things that application of basic drawing by the cad model of hull surface, and whether there is error in the geometric quality of cad model was progressed. To achieve this goal, the verification criteria and algorithm were defined and the prototype system which is based on was developed.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.1
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• pp.64-73
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• 2015

Recently, the integrated utilization of technology with IT is in demand for the effectiveness of field management together with the prevention and prompt action on safety accident at construction site. In addition, the establishment of construction site support system is necessary to implement the securing of worker's safety, smooth work instruction, efficiency in construction, and others. Data standardization and network architecture were designed regarding data and sound information for data transmission between systems and management. These were to construct USFSS based on integrated VI-GNSS technology in this research. In the stability test of data for each system constructed through it, around 98% stability was secured between workers and for transfer vehicle system within underground structure and field server system in regards to the data transmission stability, around 100% stability was secured between field server system and control system, respectively. Also, in the sound transmission stability test, around 99% reliability could be secured with 1km distance as its standard in case of sound transmission from underground structure construction site to field office near the field through wireless FRS system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.464-466
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• 2019

Controllers used in nuclear power plants require high reliability. A controller including a Field Programmable Gate Array (FPGA) and a Complex Programmable Logic Device (referred to hereinafter as FPGA) has been applied to many Nuclear Power Plants (NPP) in the past, including the APR1400 (Advanced Power Reactor 1400), a Korean digital nuclear power plant. Initially, the FPGA was considered as a general IC (Integrated Circuit) and verified only by device verification and performance testing. In the 1990s, research on FPGA verification began, and until the FPGA became a chip, it was regarded as software and the software Verification and Validation (V&V) using IEEE 1012-2004 was implemented. Currently, IEC 62566, which is a European standard, has been applied for a lot of verification. This method has been evaluated as the most sensible method to date. This is because the method of verifying the characteristics of SoC (System on Chip), which has been a problem in the existing verification method, is sufficiently applied. However, IEC 62566 is a European standard that has not yet been adopted in the United States and maintains the application of IEEE 1012 for FPGA. IEEE 1012-2004 or IEC 62566 is a technical standard. In practice, various methods are applied to meet technical standards. In this paper, we describe the procedure and important points of verification method of Nuclear Safety Class FPGA applying SoC verification method.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.356-362
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• 2022

Research related to hydrogen technology is being actively conducted around the world. Korea is also making great efforts to develop technology to leap forward as a hydrogen economy powerhouse. In particular, the world's No. 1 hydrogen vehicle penetration rate is proof of this. However, the construction of hydrogen refueling stations is being delayed. The biggest delay factor is the public opposition. As such, policies without public support cannot be successfully implemented and are not sustainable. Therefore, this study intends to analyze the factors affecting the acceptability of hydrogen refueling stations in favor of and against them. As a research method, the basic factors affecting acceptability were identified by reviewing previous studies, and a questionnaire was designed and investigated based on the established factors. The validity and reliability of the questionnaire were verified, and the hypothesis was verified through correlation analysis. And, using structural equation modeling, a factor model was developed on the acceptability of hydrogen refueling stations. As a result of the study, acceptability defined private acceptability and public acceptability. In the case of private acceptability, it was confirmed that the higher the attitude toward the environment, the higher the level of knowledge about the hydrogen charging station, and the lower the degree of feeling the risk of the hydrogen charging station, the higher the acceptability. In the case of public acceptability, it was confirmed that the higher the benefit, the better the attitude toward the environment, and the lower the risk-taking characteristics of the individual, the higher the acceptability. Therefore, in this study, based on the potential factors verified in previous studies, the main factors affecting the acceptance on hydrogen refueling stations were identified. And the acceptance model was developed using structural equation modeling. This study is expected to provide basic data to seek ways to improve the acceptance of public when implementing national policies such as hydrogen refueling stations, and to be used analysis data for scientific communication.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.118-126
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• 2024

In this paper, the research contents and results related to the automation of the hull-form optimal design of container ships are summarized. A container ship is a ship that generally operates near Froude number of 0.26. To implement hull-form optimal design automation for ships operating at this speed, an optimization algorithm, a hull-form change algorithm, a ship performance prediction algorithm, an automation algorithm, and an iterative calculation technique were applied to develop a numerical analysis computer program that enables hull-form optimal design automation of the container ship, and it was named HOTCONTAINER. In this study, a sensitivity analysis algorithm was developed and applied to appropriately set design variables for hull-form optimal design. To understand the reliability and real ship applicability of the developed algorithm, a numerical analysis was performed on KCS(KRISO Container Ship), a container ship that has been studied in various ways worldwide. Consequently, the optimal ship was derived, and the wave resistance, wave pattern, and wave height of the target and optimal ship were compared. In conclusion, compared the target ship, the optimal ship a 47.63% decrease in wave resistance, and the displacement and wet surface area decreased by 0.50% and 0.39%, respectively.