• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.66-71
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• 2016

Nowadays, a number of sensors which are placed in industrial complex are monitoring areas involving chemical leak and other faults. However, even in the presence of the sensors, chemical leaks, sometimes involving huge amount of chemicals, continuously led to big losses in the industrial complex. In most industries, sensor installation has been performed using past experience or using senor manufacturers' guideline; which leads to poor performance of the installed sensor grid. Therefore, we investigate an optimal placement methodology of point sensors for rapid detention and response when chemical leaks happen. This research suggests a generalized formulation suitable for the optimized decision making of minimizing number of sensors to be placed and increasing the fraction of covered scenarios under assumption of negligible effect of other structures. The proposed method has been verified for suitable performance for simple leak scenario simulations, by achieving the safety objectives and guaranteeing safe process operations.

• Convergence Security Journal
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• v.13 no.4
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• pp.101-108
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• 2013

Sensor network configurations are for a specific situation or environment sensors capable of sensing, processing the collected information processors, and as a device is transmitting or receiving data. It is presently serious that sensor networks provide many benefits, but can not solve the wireless network security vulnerabilities, the risk of exposure to a variety of state information. u-Healthcare sensor networks, the smaller the sensor node power consumption, and computing power, memory, etc. restrictions imposing, wireless sensing through the kind of features that deliver value, so it ispossible that eavesdropping, denial of service, attack, routing path. In this paper, with a focus on sensing of the environment u-Healthcare system wireless security vulnerabilities factors u-Healthcare security framework to diagnose and design methods are presented. Sensor network technologies take measures for security vulnerabilities, but without the development of technology, if technology is not being utilized properly it will be an element of threat. Studies suggest that the u-Healthcare System in a variety of security risks measures user protection in the field of health information will be used as an important guide.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.83-93
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• 2020

Dynamic pressure transducer needs to be flush-mounted on hardware due to frequency response characteristics of pressure transmission system. However, it is sometimes necessary to be mounted in recessed configuration due to insufficient space for sensor installation and for protection of sensor from thermal damage. Dynamic response characteristics should be considered due to distortion of original dynamic pressure signal in the pressure transmission system. In this study, small perturbation model and 2nd order reduced model were compared with experiments and a guideline for selecting a frequency response model was suggested.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.108-119
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• 2020

Dynamic pressure sensor used in liquid rocket engine combustor and gas turbine is recess-mounted usually because it should work in high temperature environment. Although recess-mounted method can protect it from combustion gas in high temperature, tube resonance occurs in a tube-cavity system. To reduce it, the infinite tube probe(ITP) was introduced in this study. The ITP model suggested in previous literature was validated with experimental data and frequency response characteristics were analyzed. Guidelines for designing the ITP were suggested as frequency response profiles varied with geometric information and physical properties using this model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.1949-1954
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• 2010

The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region(dead band) due to the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference, and an angular increment is not detected. This problem can be overcome by mechanically dithering the gyroscope. This paper presents the design method of mechanical dither by the theoretical considerations and the verification of the theoretical equations through FEM(Finite Element Method) applications. As a result, the maximum prediction error of resonant frequency and peak dither rate was under 5 percent. The theoretical equations for the mechanical performances of dither can be said to be feasible.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.470-472
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• 2016

최근 현실의 이미지나 배경에 3차원 가상 이미지를 겹쳐서 하나의 영상으로 보여주는 증강현실 기술들이 개발되고 있으며, 특히 애플리케이션에 따른 증강현실기반의 소프트웨어 들이 많이 개발되어 지고 있다. 하지만 대부분의 증강현실 기반의 애플리케이션은 GPS를 사용하여 사용자에게 서비스를 제공하는데, GPS값이 정확하지 않아 위치에 대한 신뢰도가 떨어지는 단점을 가지고 있다. 따라서 본 연구에서는 기존 GPS 기능과 지자기, 자이로, 가속도 센서를 통한 방향감지 인식을 포함하여 증강현실 기반의 애플리케이션을 개발하여 위치에 대한 신뢰도를 증가하고자 한다. 특히, 캠퍼스 가이드 서비스 애플리케이션을 개발하여 기존의 다른 애플리케이션의 문제점을 개선하고자 한다.

• Journal of Korea Game Society
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• v.21 no.5
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• pp.75-86
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• 2021

This study examines the access index to the development of immersive contents suitable for elementary school users. The findings of this study can be used as a correct development guide for companies participating in the production of virtual reality sports room contents, by providing users with an effective content experience of education and physical exercise based on the immersive content of sports, physical education, and convergence learning linked with various sensor technologies. As for the research method, this study selected content developed based on the standardization guide of the supporting institution. Through research using expert advice, interviews with sports managers, and content experience survey, this study derived a content access standard index of the virtual reality sports room. Finally, the study verified the developed contents through advanced development applying the production standard indicators.

• The Journal of Bigdata
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• v.3 no.1
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• pp.95-103
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• 2018

In recent years, many people in the manufacturing field have been making efforts to increase efficiency while analyzing manufacturing data generated in the process according to the development of ICT technology. In this study, we propose a data mining based manufacturing process using decision tree algorithm (CHAID) as part of a smart factory. We used 432 sensor data from actual manufacturing plant collected for about 5 months to find out the variables that show a significant difference between the stable process period with low defect rate and the unstable process period with high defect rate. We set the range of the stable value of the variable to determine whether the selected final variable actually has an effect on the defect rate improvement. In addition, we measured the effect of the defect rate improvement by adjusting the process set-point so that the sensor did not deviate from the stable value range in the 14 day process. Through this, we expect to be able to provide empirical guidelines to improve the defect rate by utilizing and analyzing the process sensor data generated in the manufacturing industry.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.45-48
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• 2008

Using these systems, additional information on the paintings and exhibits may be provided in the forms of text, image, speech, and video However, at museums and exhibitions, many tourists are often interested in exhibits of some particular style, authors, or coteries. The proposed Augmented Reality based guidance system may guide the users to exhibits of their interest for selective viewing. Location of the next exhibit of interest may be informed to the users as well as additional multimedia information on the exhibits of interest Such information is shown on the Augmented Reality views of the user's display device. The proposed system is composed an Ultra-Mobile PC (UMPC), an inertia tracker, and a camera. In the beginning, the user may select his/her preference on the exhibits from the menu, and then the system starts guiding by showing the relative orientation, distance, and visual cue to find a next exhibit. When the user finds and locates the matching visual cue within a matching box of the display screen, the system provides multimedia information on the exhibit. According to the preliminary user test, the proposed system is convenient and useful for navigating through large-scale exhibition.

• Tunnel and Underground Space
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• v.28 no.4
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• pp.293-303
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• 2018

Monitoring is the act of collecting and analyzing accurate engineering information using various methods and instruments. The purposes of the monitoring are design verification, construction management, quality control, safety management, and diagnose of structure etc.. The diagnose evaluation of the geotechnical structures corresponds to the confirmation of the structural performance. It is aimed to judge the soundness of geotechnical structures considering the degree of damage due to the environmental change and elapsed time. Recently, microseismicity, which is widely known in Korea, can be used for safety management and diagnoses of structure as it detects the micro-damage without disturbance of the structure. This report provides guideline on the procedure for assessing an underground oil storage cavern using microseismic monitoring techniques. Guidelines cover the selection of monitoring systems, sensor array, sensor installation and operation of systems, and interpretation.