• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.39-45
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• 2000

This paper describes the fundamental investigations on the in-process monitoring techniques focused on Acoustic Emission(AE) based on analytical method. Experiments were conducted on a CNC lathe using conventional carbide insert tools under various cutting conditions. As the result of this study a suggestion is given about the multi-purpose use of AE-signals detected with a single sensor for the monitoring of tool wear, built-up edge and chatter vibration in turning process.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1438-1447
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• 2010

Construction sites are becoming larger and complex with the growth of national economy. Accordingly, It is essential to indentify real-time information about materials, equipments and manpower during construction at job sites. Even though research utilizing cutting-edge sensors has been conducted in architectural engineering field; this area of research is almost nil in civil engineering field. Therefore a feasibility study to find a way to apply cutting-edge sensors to an in-situ tunnel construction site adopting NATM is tried as the first step. After listing all construction materials needed in each activity, the most representative materials were identified so that IT technology can be applied by attaching and monitoring sensors to the selected materials; shotcrete and lining were selected as representative materials. Moreover, a plan to visualize construction process and progress management system using selected representative materials was proposed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.799-804
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• 2011

CFRP(Carbon Fiber Reinforced Plastics) has been used many industries aerospace, automobile, medical device and building material industries, etc. Because it is lighter than other metals and has good properties, such as rigidity, strength and wear. CFRP may be cured integrity. However, it needs postprocessing similar to drilling or endmilling for shape cutting and combination of various material. In this paper, tool dynamometer and accelerometer used to signal analysis for machining properties under various cutting conditions and tool shape changes. In addition, microscope used to verify the machined CFRP surface. As the results, it was found that the cutting force and the vibration were decreased in the increasing of cutting edge (2-flute < 4-flute < composite tool), and the good machined surface can be obtained in this experiments.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.8-15
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• 2005

A new measuring method for tool deflection has been developed when sculptured surface is processed in ball-end milling. Since the vibration due to cutting forces has low frequencies, an electromagnetic sensor is used for measuring the exact vibration displacement. The amplitude and direction of vibration displacement during the cutting process is presented as orbital plot. In this study, it assumes that the vibration displacement is proportional to the length of cutting chip. Therefore, tool deflection is calculated by summing up the vibration displacement of unit chip length for engaged chip length. In addition, computer programs has been developed to predict the deflection of tools when machining sculptured surface. This developed program predicts the tool deflection per block of NC data, so that it can easily identify the parts which have the possibility of machining errors.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.245-250
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• 2002

A successful on-line monitoring system for conventional machining operations has the potential to reduce cost, guarantee consistency of product quality, improve productivity and provide a safer environment for the operator. In fee-shape machining, typical signs of tool problems such as vibration, noise, chip flow characteristics and visual signs are almost unnoticeable without the use of special equipment. These characteristics increase the importance of automatic monitoring in fine-shape machining; however, sensing and interpretation of signals are more complex. In addition, the shafts of the micro-tools break before the typical extensive cutting edge of the tool gets damaged. In this study, the existence of a relationship between the characteristics of the cutting force and tool usage was investigated, and tool breakage detection algorithm was developed and the fellowing results are obtained. In data analysis, didn't use a relative error compare which mainly used in established experiment and investigated tool breakage detection algorithm in time domain which can detect AE and cutting force signals more effective and accurate.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.301-306
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• 2022

With the recent widespread implementation of Internet of Things (IoT) technology driven by Industry 4.0, self-powered sensors for wearable and implantable systems are increasingly gaining attention. Piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), which convert biomechanical energy into electrical energy, can be considered as efficient self-powered sensor platforms. These are energy harvesters that are used as low-power energy sources. However, they can also be used as sensors when an output signal is used to sense any mechanical stimuli. For sensors, collecting high-quality data is important. However, the accuracy of sensing for practical applications is equally important. This paper provides a brief review of the performance advanced by the materials and structures of the latest PENG/TENG-based wearable sensors and intelligent applications applied using artificial intelligence (AI)

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.999-1007
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• 2012

Multi-precision multiplication over public key cryptography should be considered for performance enhancement due to its computational complexity. Particularly, embedded device is not suitable to execute high complex computation, public key cryptography, because of its limited computational power and capacity. To overcome this flaw, research on multi-precision multiplication with fast computation and small capacity is actively being conducted. In the paper, we explore the cutting-edge technology of multi-precision multiplication for efficient implementation of public key cryptography over sensor network. This survey report will be used for further research on implementation of public key cryptography over sensor network.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.11-21
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• 2016

Recently, structure safety management techniques using cutting-edge technology(Displacement senor, sensor of acceleration) has emerged as an important issue owing to the aging of infrastructure such as bridge and building. In general, the structural monitoring system for structure safety management is based on IT technology and it is expensive to install. In this paper developed an image-based structure dynamic characteristic analysis system prototype to assess the damage of structure in a more cost-effective way than traditional structure health monitoring system. The inspector can take a video of buildings or other structures with digital camera or any other devices that is passible to take video, and then using NCC calculation for image processing technique to get natural frequency. This system is analysis of damage of the structure using a compare between the frequency response ratio and functions when problems are occurs send alarm to administrator. This system is easier to install and remove than previous monitoring sensor in economical way.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.15-22
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• 2017

People generally believe that disaster forecast and warning systems and response systems are well established in the age of cutting edge technology. As a matter of fact, reliable systems to respond to disasters are not properly equipped, as we witnessed the Sewol ferry disaster in 2014. The existing forecast and warning systems are based on sensor information with low efficiency, and image information is only operated by monitoring staff manually. In addition, the interconnection between a warning system and a response system in order to decide how to cope with the recognized disaster is very insufficient. This paper introduces the CCTV based disaster recognition and real time crisis response system composed of the CCTV image recognition engine and the crisis response technique. This system has brought the possibility to overcome the limitations of existing sensor based forecast and warning systems, and to resolve the problems in the absence of monitoring staff when responding to crisis.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.301-306
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• 2023

Convergeance in the military operations can be attained by simultaneously integrating effects based on sensor, C2, shooter asset in multi-domain and there is no exception to special operations. However, because of challenges from enemy, terrain, geopraphy, and weather, it's not easy to intertwine effects created from ground, sea, air, cyber and electromagnetic spectrum, and space in special operations conducted in deep area. This study presented how to intertwine high-tech such as long-rane reconnaissance·strike drone, cutting-edge sensor, jamming pod, and modular repeater in order to offset aforementioned challenges. Several new high-tech are able to strengthen convergeance of special operations in accordance with the development of the 4th industrial revolution. Therefore, follow-up studies need to be continued making an efforts to search for them.