• Journal of the Institute of Convergence Signal Processing
• /
• v.22 no.1
• /
• pp.1-6
• /
• 2021

Recently, unmanned facilities have been introduced and operated in a way that reduces the cost and development of IT technology. Although unmanned facilities have advantages in terms of efficiency and economy, they have disadvantages such as failure of unmanned facilities and malfunctions, causing damage to facilities caused by intruders, and information leakage. In addition, it is necessary to visit the person in charge at all times to inspect the unmanned facilities, resulting in management costs. In this paper, we designed a system that checks the status of unmanned surveillance facilities in real time to check and automatically recover problems such as malfunctions, and to notify managers of situations by text messages in real time. The system to be designed consists of an integrated network video server (NVR) that receives and determines information on the operation status of the main equipment such as video, sound, and lighting, and a real-time text message using an SMS server.

• 재활복지
• /
• v.20 no.4
• /
• pp.31-54
• /
• 2016

The purpose of this study is to explore the improvement method of the emergency safety system as a social protection scheme for the elderly living alone with severe disabilities. The study was conducted by randomly choosing three regions in the metropolitan area (Jongno-gu, Seoul), the small-medium city (Yongin-si, Gyeonggi-do) and the rural area (Geochang-gun, Gyeongsangnam-do) among 17 cities and counties nationwide. The study method is based on the interview form of the structured questionnaires with city officials, county officials, and center operators. According to the results of the interview analysis, it was recognized that there was a need for an emergency safety system for the elderly living alone with severe disabilities. In spite of this necessity, there were problems about publicity for the discovery of victims of the blind spot in welfare, about inconvenience due to frequent malfunctions of the emergency equipment, about insufficient awareness of the security of the emergency officials and about supply and demand of manpower for 24-hour monitoring service. In order to improve the effective operation of the emergency safety system, it was the most urgent issue to formulate the legislation for responding to the crisis management of the vulnerable. A suggestion of this study is to build a safety system in which one-stop service is provided for the realization of compact welfare through the establishment of a MOU for linkage with community organizations, the full inspection of emergency equipment to solve safety equipment malfunction problems and the manpower supplement for 24-hour monitoring.

• International Journal of Highway Engineering
• /
• v.17 no.6
• /
• pp.1-9
• /
• 2015

PURPOSES : The objective of this study is to propose a quality control and quality assurance method for use during asphalt pavement construction using non-destructive methods, such as ground penetrating radar (GPR) and an infrared (IR) camera. METHODS : A 1.0 GHz air-coupled GPR system was used to measure the thickness and in situ density of asphalt concrete overlay during the placement and compaction of the asphalt layer in two test construction sections. The in situ density of the asphalt layer was estimated based on the dielectric constant of the asphalt concrete, which was measured as the ratio of the amplitude of the surface reflection of the asphalt mat to that of a metal plate. In addition, an IR camera was used to monitor the surface temperature of the asphalt mat to ensure its uniformity, for both conventional asphalt concrete and fiber-reinforced asphalt (FRA) concrete. RESULTS : From the GPR test, the measured in situ air void of the asphalt concrete overlay gradually decreased from 12.6% at placement to 8.1% after five roller passes for conventional asphalt concrete, and from 10.7% to 5.9% for the FRA concrete. The thickness of the asphalt concrete overlay was reduced from 7.0 cm to 6.0 cm for the conventional material, and from 9.2 cm to 6.4 cm for the FRA concrete. From the IR camera measurements, the temperature differences in the asphalt mat ranged from $10^{\circ}C$ to $30^{\circ}C$ in the two test sections. CONCLUSIONS : During asphalt concrete construction, GPR and IR tests can be applicable for monitoring the changes in in situ density, thickness, and temperature differences of the overlay, which are the most important factors for quality control. For easier and more reliable quality control of asphalt overlay construction, it is better to use the thickness measurement from the GPR.

• Journal of the Society of Disaster Information
• /
• v.19 no.1
• /
• pp.204-215
• /
• 2023

Purpose: In this study, it was proposed a plan to build the Continuous Preventive Audit System in the military Organization with the expectation that we will develop an efficient audit method under the rapidly changing audit and work environment in the future. Method: it was examined the realities and problems of the military self-audit, the cases of the Continuous Preventive Audit System currently being used by government departments and institutions and internal control inspection of the information system of the Foreign Audit Office. Result: Government departments, agencies, and foreign auditors have established a Continuous Preventive Audit System to overcome the problems and limitations of their own audits, ensuring accounting accident prevention and audit work efficiency and are focused on auditing internal controls of information systems. Conclusion: In the future, more specific studies on the design of detailed scenarios for each function of defense work and the research and analysis on the improvement of defense information system should be followed for the establishment and settlement of a more specific Continuous Preventive Audit System.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.23 no.2
• /
• pp.133-139
• /
• 2003

In order to extend the life time of building and civil infra-structure, nowadays, patch type fibrous composite materials are widely used. Repaired concrete columns and beams gain the stiffness and strength, but they lose toughness and show brittle failure. Usually, the cracks of concrete structures are visible with naked eyes and the status of the structure in the life cycle is estimated with visible inspection. After repairing of the structure, crack visibility is blocked by repaired carbon sheets. Therefore, structural monitoring after repairing is indispensible and self diagnosis method with optical fiber sensor is very useful. In this paper, peel-out effects is detected with optical fiber sensors and the strain difference between main structure and repaired carbon sheets when they separate each other.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.5
• /
• pp.1-8
• /
• 2006

The objective of this study is to assess impacts of sorption heterogeneity on the transport of leachate leaked from unlined landfill sites and is accomplished by examining the results from a series of Monte-Carlo simulations. For random distribution coefficient ($K_{d}$) fields with four different levels of heterogeneity ranging from homogeneous to highly heterogeneous, the transport of leachate was investigated by linking a saturated flow model with a contaminant transport model. Impacts of a chemical heterogeneity were evaluated using point statistics values such as mean, standard deviation, and coefficient of variation of the concentration obtained at monitoring wells from 100 Monte-Carlo trials. Inspection of point statistics shows that the distribution of distribution coefficient in the landfill site proves to be an important parameter in controlling leachate concentrations. In comparison to homogeneous sorption, heterogeneous $K_{d^-}$ fields produce the variability in the leachate concentration for different realizations. The variability increases significantly as the variance in the $K_{d^-}$ field and the travel time between source and monitoring well increase. These outcomes indicate that use of a constant homogeneous $K_{d}$ value for predicting the transport of leachate can result in significant error, especially when variability in $K_{d}$ is high.

• Korean journal of applied entomology
• /
• v.60 no.3
• /
• pp.269-276
• /
• 2021

During 15 months from 13. Jul. 2018 to 29. Oct. 2019, we monitored on the hitchhiker insect pests from a total of 306 foreign vessels entering into Korea. As the results, a total of 805 samples of the hitchhiker insects were collected using simply collecting method by hands and identified as 379 species of 78 families under 12 orders on the basis of integrative species identification. Among them, 42 species (67 individuals) of 21 families under seven orders were detected as not-distributed species in South Korea. Of the 42 not-distributed species, seven species were multiply detected in 2018 and 2019, and two species, Erthesina fullo (Pentatomidae, Hemiptera) and Tessaratoma papilosa (Tessaratomidae, Hemiptera) were discovered as regulated insect pest. Therefore, we reported on the 42 not-distributed species in South Korea with the data sheets for the establishment of a monitoring plan on the not-distributed species and the risk assessments on invasive or invasive likelihood species.

• Smart Structures and Systems
• /
• v.17 no.3
• /
• pp.363-389
• /
• 2016

Deficient modes that cannot be always identified from different sets of measurement data may exist in the application of operational modal analysis such as the stochastic subspace identification techniques in large-scale civil structures. Based on a recent work using the long-term ambient vibration measurements from an instrumented cable-stayed bridge under different wind excitation conditions, a benchmark problem is launched by taking the same bridge as a test bed to further intensify the exploration of mode identifiability. For systematically assessing this benchmark problem, a recently developed SSI algorithm based on an alternative stabilization diagram and a hierarchical sifting process is extended and applied in this research to investigate several sets of known and blind monitoring data. The evaluation of delicately selected cases clearly distinguishes the effect of traffic excitation on the identifiability of the targeted deficient mode from the effect of wind excitation. An additional upper limit for the vertical acceleration amplitude at deck, mainly induced by the passing traffic, is subsequently suggested to supplement the previously determined lower limit for the wind speed. Careful inspection on the shape vector of the deficient mode under different excitation conditions leads to the postulation that this mode is actually induced by the motion of the central tower. The analysis incorporating the tower measurements solidly verifies this postulation by yielding the prevailing components at the tower locations in the extended mode shape vector. Moreover, it is also confirmed that this mode can be stably identified under all the circumstances with the addition of tower measurements. An important lesson learned from this discovery is that the problem of mode identifiability usually comes from the lack of proper measurements at the right locations.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.7
• /
• pp.7-15
• /
• 2020

Recently, the fourth industrial revolution has been presented as a new paradigm and additive manufacturing (AM) has become one of the most important topics. For this reason, process monitoring for each cross-sectional layer of additive metal manufacturing is important. Particularly, deep learning can train a machine to analyze, optimize, and repair defects. In this paper, image classification is proposed by learning images of defects in the metal cross sections using the convolution neural network (CNN) image labeling algorithm. Defects were classified into three categories: crack, porosity, and hole. To overcome a lack-of-data problem, the amount of learning data was augmented using a data augmentation algorithm. This augmentation algorithm can transform an image to 180 images, increasing the learning accuracy. The number of training and validation images was 25,920 (80 %) and 6,480 (20 %), respectively. An optimized case with a combination of fully connected layers, an optimizer, and a loss function, showed that the model accuracy was 99.7 % and had a success rate of 97.8 % for 180 test images. In conclusion, image labeling was successfully performed and it is expected to be applied to automated AM process inspection and repair systems in the future.

• Journal of the Korean Society of Safety
• /
• v.28 no.3
• /
• pp.44-50
• /
• 2013

Process gas piping is one of the most basic components frequently used in the refinery and petrochemical plants. Many kinds of by-product gas have been used as fuel in the process plants. In some plants, natural gas is additionally introduced and mixed with the byproduct gas for upgrading the fuel. In this case, safety or design margin of the changed piping system of the plant should be re-evaluated based on a proper design code such as ASME or API codes since internal pressure, temperature and gas compositions are different from the original plant design conditions. In this study, series of piping stress analysis were conducted for a process piping used for transporting the mixed gas of the by-product gas and the natural gas from a mixing drum to a knock-out drum in a refinery plant. The analysed piping section had been actually installed in a domestic industry and needed safety audit since the design condition was changed. Pipe locations of the maximum system stress and displacement were determined, which can be candidate inspection and safety monitoring points during the upcoming operation period. For studying the effects of outside air temperature to safety the additional stress analysis were conducted for various temperatures in $0{\sim}30^{\circ}C$. Effects of the friction coefficient between the pipe and support were also investigated showing a proper choice if the friction coefficient is important. The maximum system stresses were occurred mainly at elbow, tee and support locations, which shows the thermal load contributes considerably to the system stress rather than the internal pressure or the gravity loads.