• Journal of the Korea Safety Management & Science
• /
• v.23 no.3
• /
• pp.1-9
• /
• 2021

Crane is an important equipment for the transport of heavy goods in industrial sites, but it is also known as one of the most fatal machines. In order to reduce crane accidents, it is necessary to minimize human errors during crane operations. To achieve this, ergonomic design principles are recommended to be reflected from the crane design stage. The study analyzed the safety certification standards for crane that should be fulfilled at the crane design and manufacturing stage. This study selected five representative ergonomic design principles (feedback, compatibility, consistency, full-proof, and fail-safe) by surveying heuristic evaluation principles that are widely used for usability evaluation in early design stage. Next, the principles were applied to the safety certification standards to identify insufficient clauses. This study identified 12 insufficient clauses out of 119 in the current safety certification standards for crane and discussed their improvement directions to comply the ergonomic principles. The analysis results of this study can help of improving the safety certification standards and the method used in this study can also be applied to identify insufficient clauses in the safety certification standards for other industrial machines such as press machine and lift.

• Nuclear Engineering and Technology
• /
• v.54 no.1
• /
• pp.186-192
• /
• 2022

Flow accelerated corrosion (FAC) is a type of pipe corrosion in which the pipe thickness decreases depending on the fluid flow conditions. In nuclear power plants, FAC mainly occurs in the carbon steel pipes of a secondary system. However, because the temperature of a secondary system pipe is over 150 ℃, in situ monitoring using a conventional ultrasonic non-destructive testing method is difficult. In our previous study, we developed a waveguide ultrasonic thickness measurement system. In this study, we applied a waveguide ultrasonic thickness measurement system to monitor the thinning of the pipe according to the change in pH. The Korea Atomic Energy Research Institute installed FAC-proof facilities, enabling the monitoring of internal fluid flow conditions, which were fixed for ~1000 h to analyze the effect of the pH. The measurement system operated without failure for ~3000 h and the pipe thickness was found to be reduced by ~10% at pH 9 compared to that at pH 7. The thickness of the pipe was measured using a microscope after the experiment, and the reliability of the system was confirmed with less than 1% error. This technology is expected to also be applicable to the thickness-reduction monitoring of other high-temperature materials.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.2
• /
• pp.325-336
• /
• 2023

With the development of autonomous driving technology, the number of external contact sensors mounted on vehicles is increasing, and the importance is also rising. The vehicular ultrasonic sensor uses the LIN protocol in the form of a bus topology and reports a status message about its surroundings through the vehicle's internal network. Since ultrasonic sensors are vulnerable to various threats due to poor security protocols, physical testing on actual vehicle is needed. Therefore, this paper developed a LIN-CAN co-analysis testbed with a jig for location-specific distance test to examine the operational relation between LIN and CAN caused by ultrasonic sensors.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.6
• /
• pp.78-86
• /
• 2014

In this paper, a novel intensity-based fiber optic vibration sensor using a mass-spring structure, which consists of four serpentine flexure springs and a rectangular aperture within a proof mass, is proposed and its feasibility test is given by the simulation and experiment. An optical collimator is used to broaden the beam which is modulated by the displacement of the rectangular aperture within the proof mass. The proposed fiber optic vibration sensor has been analyzed and designed in terms of the optical and mechanical parts. A mechanical structure has been designed using theoretical analysis, mathematical modeling, and 3D FEM (Finite Element Method) simulation. The relative aperture displacement according to the base vibration is given using FEM simulation, while the output beam power according to the relative displacement is measured by experiment. The simulated sensor sensitivity of $15.731{\mu}W/G$ and detection range of ${\pm}6.087G$ are given. By using reference signal, the output signal with 0.75% relative error shows a good stability. The proposed vibration sensor structure has the advantages of a simple structure, low cost, and multi-point sensing characteristic. It also has the potential to be made by MEMS (Micro-Electro-Mechanical System) technology.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1289-1301
• /
• 2011

In this paper, flux estimation method at the Induction motor is applied to stability flux estimate of possibility in overall speed domain. angle operation has voltage and current and speed information using the Induction motor direct control method. Induction motor direct control is material to flux information. Exact flux estimation method to using current model flux estimator of low-speed domain and voltage model flux estimator of high-speed domain. Speed and current and flux controller using PI controller. And error of integral requital for add to Anti-Windup PI controller. Verified to performance of Current model Flux controller and voltage model flux controller using Matlab / Simulink. Analysis has parameter influence of direct vector control and indirect vector control at the Induction motor vector control. So, verified to minute control. Analyzed to simulation result and proof to validity of presented algorithm.

• Journal of Communications and Networks
• /
• v.11 no.6
• /
• pp.544-555
• /
• 2009

This work continues a trend of developments aimed at exploiting the physical layer of the open systems interconnection (OSI) model to enhance wireless network security. The goal is to augment activity occurring across other OSI layers and provide improved safeguards against unauthorized access. Relative to intrusion detection and anti-spoofing, this paper provides details for a proof-of-concept investigation involving "air monitor" applications where physical equipment constraints are not overly restrictive. In this case, RF fingerprinting is emerging as a viable security measure for providing device-specific identification (manufacturer, model, and/or serial number). RF fingerprint features can be extracted from various regions of collected bursts, the detection of which has been extensively researched. Given reliable burst detection, the near-term challenge is to find robust fingerprint features to improve device distinguishability. This is addressed here using wavelet domain (WD) RF fingerprinting based on dual-tree complex wavelet transform (DT-$\mathbb{C}WT$) features extracted from the non-transient preamble response of OFDM-based 802.11a signals. Intra-manufacturer classification performance is evaluated using four like-model Cisco devices with dissimilar serial numbers. WD fingerprinting effectiveness is demonstrated using Fisher-based multiple discriminant analysis (MDA) with maximum likelihood (ML) classification. The effects of varying channel SNR, burst detection error and dissimilar SNRs for MDA/ML training and classification are considered. Relative to time domain (TD) RF fingerprinting, WD fingerprinting with DT-$\mathbb{C}WT$ features emerged as the superior alternative for all scenarios at SNRs below 20 dB while achieving performance gains of up to 8 dB at 80% classification accuracy.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.437-441
• /
• 2001

This paper describes the construction of a circular polariscope. Generally, a circular polariscope contains four optical elements and a light source. The first element following the light source is called the polarizer. It converts the ordinary light into plane-polarized light. The second element is a quarter wave plate which converts the plane-polarized light into circularly polarized light. Following the quarter wave plate, a specimen made of transparent photoelastic material is located in a loading device. The second quarter wave plate is set and the last element is the analyzer. These polarizing elements, two quarter wave plates and two polarizing filters, were purchased from the USA. Frames and other structures for holding polarizing filters were machined and assembled to be rotated. Light box, which include four incandescent lamps and two sodium-vapor lamps, was made. In order to proof the function of the newly built polariscope, Tardy compensation test was applied to a rectangular shaped specimen made of poly-carbonate material (PSM1). The error of the fringe constant, which was measured by the newly built polariscope, was within 4.4 percent compared to the standard value of this material. It is possible to make a good quality of polariscope if accurate polarizing filters will be used.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.1
• /
• pp.94-101
• /
• 2018

With the development of industrial technology and science, production and manufacturing facilities have been enhanced and improved, and the importance of the safety of workers has also been regulated and limited by various safety management methods. As a way to secure the safety of the workers from the production facility, the fail-safe and fool-proof methods are now being applied. Any possible insecure behavior and unsafe conditions can be removed by adopting the standards and specifications that are now secure the safety of workers and equipment. This research analyzes EN ISO 13849-1 international and European standards during CE certification. In order to secure acceptable reduced risks, the risk assessment process of ISO 12100 and the processes for reducing its risk are applied. In the current ISO 13849-1 standard, the criteria for the required performance level PLr (Required Performance Level) for the applicable risk and safety functions through the risk assessment are subjective and not subdivided. Therefore, the evaluation criteria are likely to cause judge's judgement error due to qualitative judgement. This research focuses on evaluation and acceptable performance level setting for the safety circuit of the equipment. We propose an objective and specific evaluation criteria to secure safety, and the proposed evaluation criteria are applied to the case study of the safety circuit for the equipment. In order to secure the safety of the entire safety circuit, the improvement of the MTTFd and DC level related to the SRP/CS (Safety-Related Parts of Control Systems)' lifetime is required for the future research.

• International conference on construction engineering and project management
• /
• 2020.12a
• /
• pp.87-95
• /
• 2020

Generally, occupational safety and particularly construction safety is an intricate phenomenon. Industry professionals have devoted vital attention to enforcing Occupational Safety and Health (OHS) from the last three decades to enhance safety management in construction. Despite the efforts of the safety professionals and government agencies, current safety management still relies on manual inspections which are infrequent, time-consuming and prone to error. Extensive research has been carried out to deal with high fatality rates confronting by the construction industry. Sensor systems, visualization-based technologies, and tracking techniques have been deployed by researchers in the last decade. Recently in the construction industry, computer vision has attracted significant attention worldwide. However, the literature revealed the narrow scope of the computer vision technology for safety management, hence, broad scope research for safety monitoring is desired to attain a complete automatic job site monitoring. With this regard, the development of a broader scope computer vision-based risk recognition system for correlation detection between the construction entities is inevitable. For this purpose, a detailed analysis has been conducted and related rules which depict the correlations (positive and negative) between the construction entities were extracted. Deep learning supported Mask R-CNN algorithm is applied to train the model. As proof of concept, a prototype is developed based on real scenarios. The proposed approach is expected to enhance the effectiveness of safety inspection and reduce the encountered burden on safety managers. It is anticipated that this approach may enable a reduction in injuries and fatalities by implementing the exact relevant safety rules and will contribute to enhance the overall safety management and monitoring performance.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.11
• /
• pp.5551-5556
• /
• 2012

Cytological examination is widely used as a diagnostic tool because of the ease of collecting cells from the involved area. However, the diagnostic yield of cytological examination is unsatisfactory; the reasons include sampling error, poorly prepared samples, small numbers of malignant cells, and low grades of cellular atypia. In this study, we focused on the high infectivity of adenovirus towards epithelial cells and applied the luciferase-expressing adenoviral vector to a new cancer cell detection tool. In addition, adenoviral infectivity was enhanced by modifying viral fiber proteins. The sensitivity of the diagnostic tool was tested using the NCI-H1299 lung cancer cell line, and validated in body fluid samples from cancer patients with a variety of etiology. Results showed that the adenovirus efficiently transfected NCI-H1299 with high sensitivity. Only 10 cancer cells were sufficient for detection of luciferase signals. In body fluid samples, the adenovirus confirmed the diagnosis for malignant and benign cancer, but not in non-epithelial cell derived samples. This study provides proof-of-concept for a more reliable and sensitive diagnostic tool for epithelium-derived cancer.