• Journal of the Korean Society of Safety
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• v.22 no.3 s.81
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• pp.7-12
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• 2007

This paper presents the development of an electrical fire detection system using digital temperature and current detectors in order to sound for electrical fire in advance. As the demand for electricity is increasing and industrial facilities are getting more complex and larger in size, the losses of human life and property are on the increase by electrical fires. In order to prevent electrical fires, it is required to find out fire signatures, or electric signal of the overcurrent and overheating. Therefore, in this paper, developed is an electrical fire detection system based on the detection of signal for overcurrent and overheating to prevent electrical accidents in advance that happen in electrical wires. The developed system gives an alarm by computer monitor, speaker system and mobile phone before electrical fires occur and give severe damages to human beings and properties, and the system can be implemented and supplied for business and residental buildings at a low price. The usefulness and validity of the system, also, verified in this paper by case study and experiments.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.615-620
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• 2015

This paper deals with a fault detection system design for a boiler-turbine control system of thermal power plant. We described the nonlinear properties of the boiler-turbine dynamics as a T-S fuzzy system with time varying measurable parameters. We design a residual generator using an observer based fault detection filter. In order to identify the faulted output sensor, an approximate inverse system is connected to the outport of the fault detection filter. We demonstrate the efficiency of the suggested design method via computer simulations.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.853-859
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• 2017

Terrorists always threats the global security with the possibility of using prohibited warfare, NBCs(Nuclear, Biological and Chemical Warfare). Compared to other prohibited warfares, most of biological warfare agents (BWAs) have no physical properties and time delays from spread to affect. Therefore the early detection is important to protect and decontaminate from BWAs. On the preliminary detection stage for suspicious material, most of detection kits only serve to know weather the BWAs exists or not. Due to this reason, simple field confirmation testing for suspicious substances have been used to identify materials which show negative result on detection kits. Considering the current Lab on a Chip(LOC) technologies, we suggest simple identification platform for unknown suspicious substances based on paper fluidics. We hope that our research will envision the future direction for the specific point-of-view for LOC technologies on detection strategy of BWAs.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.346-351
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• 2013

We developed a one-step method for fabrication of addressable suspended SWNT films and demonstrate excellent detection performance of paraoxon based on OPH-immobilized SWNT films for environmental monitoring. For dispersed SWNT suspension, COOH-SWNT was prepared by the oxidation of carbon nanotubes using acid treatment and sonication. Suspended SWNT-film was fabricated between cantilever electrodes by dielectrophoretic force and surface tension of the water meniscus. After that, OPH were immobilized on suspended SWNT-films by nonspecific binding for enzymatic hydrolysis of paraoxon. The electrical properties of the SWNT films were measured in real time at room temperature. Structurally suspended SWNT films from substrate surface made possible rapid and highly sensitive detection of target molecules with increased convectional and diffusional fluxes of the molecules and with a large binding surface area. SWNT film FET resulted in a real-time, label-free, and electrical detection of paraoxon to the concentration of ca. $10{\mu}m$ with a step-wise rapid response time of several seconds.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.47-51
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• 2019

Sweat-based glucose sensors are being widely investigated and researched as they facilitate painless and continuous measurement. However, because the concentration of sweat glucose is almost a hundred times lower than that of blood glucose, it is important to develop electrochemical sensing electrode materials that are highly sensitive to glucose molecules for the detection of low concentrations of glucose. The preparation of a flexible and ultra-sensitive sensor for detection of sweat glucose is presented in this study. Oxygen and nitrogen are removed from the surface of a polyimide film by exposure to a CO2 laser; hence, laser-induced graphene (LIG) is formed. The fabricated LIG electrode showed favorable properties of high roughness and good stability, flexibility, and conductivity. After the laser scanning, Pt nanoparticles (PtNP) with good catalytic behavior were electrodeposited and the glucose sensor thus developed, with a LIG/PtNP hybrid electrode, exhibited a high order of sensitivity and detection limit for sweat glucose.

• Journal of Sensor Science and Technology
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• v.28 no.3
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• pp.139-145
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• 2019

Precautionary detection of chemical warfare agents (CWAs) has been an important global issue mainly owing to their toxicity. To achieve proper detection, many studies have been conducted to develop sensitive gas sensors for CWAs. In particular, metal-oxide semi-conductors (MOS) have been investigated as promising sensing materials owing to their abundance in nature and excellent sensitivity. In this review, we mainly focus on various MOS-based gas sensors that have been fabricated for the detection of two specific CWA simulants, 2-chloroethyl ethyl sulfide (2-CEES) and dimethyl methyl phosphonate (DMMP), which are simulants of sulfur mustard and sarin, respectively. In the case of 2-CEES, we mainly discuss $CdSnO_3-$ and ZnO-based sensors and their reaction mechanisms. In addition, a method to improve the selectivity of ZnO-based sensors is mentioned. Various sensors and their sensing mechanisms have been introduced for the detection of DMMP. As the reaction with DMMP may directly affect the sensing properties of MOS, this paper includes previous studies on its poisoning effect. Finally, promising sensing materials for both gases are proposed.

• Journal of Surface Science and Engineering
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• v.54 no.4
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• pp.194-199
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• 2021

In this study, rebar corrosion detection sensor was fabricated using multi-walled carbon nanotubes (MWCNTs). MWCNTs were pre-treated in the acid electrolytes to attach the carboxylic acid to the surface of MWCNTs. The fabricated sensor was attached on the surface of rebar and it detected the corrosion of steel using LCR meter with variation of capacitance. The surface morphology and electrical properties were characterized using scanning electron microscope (SEM) and electrical test equipment, respectively. To verify the corrosion detection characteristics, comparison experiment using plastic bar was performed. Moreover, mechanism of corrosion detection sensor was discussed.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.153-163
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• 2015

This paper proposes a rain detection and removal algorithm that is robust against camera motion in video sequences. In detection part, the proposed algorithm initially detects possible rain streaks by using intensity properties and spatial properties. Then, the rain streak candidates are selected based on Gaussian distribution model. In removal part, a non-rain block matching algorithm is performed between adjacent frames to find similar blocks to the block that has rain pixels. If the similar blocks to the block are obtained, the rain region of the block is reconstructed by non-local means (NLM) filter using the similar neighbors. Experimental results show that the proposed algorithm outperforms the previous works in terms of subjective visual quality of de-rained video sequences.

• Fire Science and Engineering
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• v.30 no.2
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• pp.19-26
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• 2016

In this study, we conducted a low temperature operating test and miniature tunnel model test to study the fire detection capability and properties of an early fire detection system using an optical sensor linear detector that can be installed in harsh environments such as tunnel or utility-pipe conduits which are becoming the major and national infrastructure facilities. The test showed that the optical sensor linear detector was the only one functioned properly among five thermal detectors installed at a low temperature of $-20^{\circ}C$ for 5 days. To study were analyzed adaptability of optical sensor linear detector in the windy tunnel, the operating properties of the optical sensor linear detector when the wind velocity was varied between 0 m/s and 1 m/s in a miniature tunnel model. The temperature change was high when the wind velocity was 0 m/s.

• Smart Structures and Systems
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• v.18 no.5
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• pp.983-1004
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• 2016

Nowadays, there are two classes of methods for damage detection in structures consisting of static and dynamic. The dynamic methods are based on studying the changes in structure's dynamic characteristics. The theoretical basis of this method is that damage causes changes in dynamic characteristics of structures. The dynamic methods are divided into two categories: signal based and modal based. The modal based methods utilize the modal properties consisting of natural frequencies, modal damping and mode shapes. As the modal properties are sensitive to changes in the structure, these can be used for detecting the damages. In this study, using dynamic method and modal based approach (natural frequencies and mode shapes), the objective function is formulated. Then, detection of damages of truss structures is addressed by using Simplified Dolphin Echolocation algorithm and solving inverse optimization problem. Many scenarios are used to simulate the damages. To demonstrate the ability of the algorithm, different truss structures with several multiple elements scenarios are tested using a few runs. The influence of the two different levels of noise in the modal data for these scenarios is also considered. The last example of this article is investigated using a different mutation. This mutation obtains the exact answer with fewer loops and population by limited computational effort.