• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.5
• /
• pp.1011-1016
• /
• 2018

Ubiquitous services for the convenience and safety of human beings along with the development of society are being realized through RFID technology and sensor network, and its application range of fields is also broaden. However, since the USN contains all the information of individuals and things, all of its private spaces can be attacked by external attacks; so, that the problem of security continues to arise. We designed a one-way chaotic feedback synchronization method as a secure communication method to fit the USN composed of one sync node and n number of sensor nodes. We designed the method by which the sensor node is synchronized in one direction of the sync node. This method solves the problem that all sensor nodes need to be resynchronized when the sync node is changed, which is shown in bidirectional synchronization. This is a security method that can be effectively applied to 1:n communication such as USN.

• International Journal of Highway Engineering
• /
• v.16 no.3
• /
• pp.51-57
• /
• 2014

PURPOSES : This study is to suggest tunnel length to spray curing compound, based on the field tests. METHODS : At first field test, length from the entrance of tunnel to wet wall was checked by visual survey. The second and third test, various sensors were installed in concrete or in tunnel, such as RH sensor, temperature sensor, portable weather station and etc.. And also, test for bleeding and retaining water of concrete were conducted to evaluate environmental effect on concrete pavement. RESULTS : The result of the field experiment for tunnel length to spray curing compound indicates that length changes depending on tunnel length, season, and location. Environmental condition of a short tunnel was not much different between location near entrance and at center of tunnel. However, in case of a medium and long tunnel, effect of outside environmental condition decreased, when location moved into tunnel center of it. CONCLUSIONS : From the testing results, it can be proposed that optimum tunnel length to spray curing compound is 60m for a medium and long tunnel, and whole length for a short tunnel.

• ETRI Journal
• /
• v.29 no.4
• /
• pp.411-420
• /
• 2007

The steady evolution of mapping technology is leading to an increasing availability of multi-sensory geo-spatial datasets, such as data acquired by single-head frame cameras, multi-head frame cameras, line cameras, and light detection and ranging systems, at a reasonable cost. The complementary nature of the data collected by these systems makes their integration to obtain a complete description of the object space. However, such integration is only possible after accurate co-registration of the collected data to a common reference frame. The registration can be carried out reliably through a triangulation procedure which considers the characteristics of the involved data. This paper introduces algorithms for a multi-primitive and multi-sensory triangulation environment, which is geared towards taking advantage of the complementary characteristics of spatial data available from the above mentioned sensors. The triangulation procedure ensures the alignment of involved data to a common reference frame. The devised methodologies are tested and proven efficient through experiments using real multi-sensory data.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.22 no.4
• /
• pp.229-240
• /
• 2019

3D geo-spatial model have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, the demand for high quality 3D spatial information such as precise road map construction has explosively increased, MMS and UAV techniques have been actively used to acquire them more easily and conveniently in surveying and geo-spatial field. However, in order to perform 3D modeling by integrating the two data set from MMS and UAV, its so needed an proper registration method is required to efficiently correct the difference between the raw data acquisition sensor, the point cloud data generation method, and the observation accuracy occurred when the two techniques are applied. In this study, we obtained UAV point colud data in Yeouido area as the study area in order to determine the automatic registration performance between MMS and UAV point cloud data using ICP(Iterative Closet Point) method. MMS observations was then performed in the study area by dividing 4 zones according to the level of overlap ratio and observation noise with based on UAV data. After we manually registered the MMS data to the UAV data, then compared the results which automatic registered using ICP method. In conclusion, the higher the overlap ratio and the lower the noise level, can bring the more accurate results in the automatic registration using ICP method.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.24 no.2
• /
• pp.102-116
• /
• 2021

For the safe operation of autonomous vehicles, the representative technology of the 4^th industrial revolution era, a combination of various technologies such as sensor technology, software technology and car technology is required. An autonomous vehicle is a vehicle that recognizes current location and situation by using the various sensors, and makes its own decisions without depending on the driver. Perfect recognition technology is required for fully autonomous driving. Since the precise road maps provide various road information including lanes, stop lines, traffic lights and crosswalks, it is possible to minimize the cognitive errors that occur in autonomous vehicles by using the precise road maps with location information of the road facilities. In this study, the definition, necessity and technical trends of the precise road map have been analyzed, and the HD(High Definition) map prototype based on the web GIS has been built in the autonomous driving-specialized areas of Daegu Metropolitan City(Suseong Medical District, about 24km), the Happy City of Sejong Special Self-Governing City(about 33km), and the FMTC(Future Mobility Technical Center) PG(Proving Ground) of Seoul National University Siheung Campus using the MMS(Mobile Mapping System) surveying results given by the National Geographic Information Institute. In future research, the built-in precise road map service will be installed in the autonomous vehicles and control systems to verify the real-time locations and its location correction algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.8
• /
• pp.5534-5540
• /
• 2015

This In the railway signaling system, applications of axle counter in addition to track circuit goes on increasing for detecting train position. Consequently, this paper compares sensor methods of axle counter with between geo-magnetism method and proximity sensor method. And it presents differences and results, to improve reliabilities of train detection and axle counting. Also, this article presents an applied result which is based on field experience, with regard to installation, considering attachment condition of sensor part for accurate axle counting. This study acquires expandability that is able to perform not only axle counting function but also various other functions (direction detection of train, speed detection of train, and so on). It was a result of a change of design in order to judge phase difference of sensors, to improve reliability of axle counting. Furthermore, it does not subordinate to characteristics (type, weight of train). And it is confirmed that the omission of axle counting was not occurred in 350km/h. This was the result of Lab test after the construction of transfer equipment of trial axle and Test Bed for axle counting. Both of them are self-productions. Through this, it prepares foundation which is able to apply not only to train detection but also to speed of passing trains, formation number of trains, detector locking condition - when the train passes the section of switch point, and level crossing devices. Furthermore, it would be judged to contribute safety train operation if proximity sensor method applies to the whole railway signaling system from now on.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2007.04a
• /
• pp.135-140
• /
• 2007

Due to the expensiveness of IKONOS Pro and Precision Products, it is attractive to use the low-cost IKONOS Geo Product with vendor-provided RPCs to produce highly accurate mapping products. The imaging geometry of IKONOS high-resolution imagery is described by RFs instead of rigorous sensor models. This paper presents four different models defined respectively in object space and image space to improve the accuracies of the RF-derived ground coordinates. The four models include the offset model, the scale & offset model, the affine model and the 2nd-order polynomial model. Different configurations of ground control points (GCPs) are carefully examined to evaluate the effect of the GCPs arrangement on the accuracy of ground coordinates. The experiment also evaluates the effect of different cartographic parameters such as the number location, and accuracy of GCPs on the accuracy of geopositioning.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.2
• /
• pp.154-159
• /
• 2013

Alignment tolerance for EO/IR airborne camera using common optic is an important factor in stabilization accuracy and geo-pointing accuracy. Before airborne camera is mounted on the aircraft, defining alignment tolerance and verification of it is essential in production as well as research and development. In this paper we establish basic concept on the definition and elements of alignment tolerance for airborne camera and propose how to measure each of those elements. Components and the measurement sequence of alignment tolerance are as follows: 1) tolerance of alignment between EO and IR LOS. 2) tolerance of sensor alignment. 3) tolerance of position reporting accuracy. 4) tolerance of mount alignment

• Smart Structures and Systems
• /
• v.16 no.6
• /
• pp.1147-1167
• /
• 2015

Wireless smart sensors, which have become popular for monitoring applications, are an attractive option for implementing structural control systems, due to their onboard sensing, processing, and communication capabilities. However, wireless smart sensors pose inherent challenges for control, including delays from communication, acquisition hardware, and processing time. Previous research in wireless control, which focused on semi-active systems, has found that sampling rate along with time delays can significantly impact control performance. However, because semi-active systems are guaranteed stable, these issues are typically neglected in the control design. This work achieves active control with smart sensors in an experimental setting. Because active systems are not inherently stable, all the elements of the control loop must be addressed, including data acquisition hardware, processing performance, and control design at slow sampling rates. The sensing hardware is shown to have a significant impact on the control design and performance. Ultimately, the smart sensor active control system achieves comparable performance to the traditional tethered system.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.92-104
• /
• 2005

Over the past decade, major advances have occurred in both understanding and practice with regard to assessment and mitigation of hazard area associated with seismically induced soil liquefaction. In this paper, assessment of liquefaction resistance of soil are reviewed from the recent researches. In addition site characteristics investigation methods and tests for seismic design and liquefaction analysis are reviewed. Finally, introduction and characteristics of remedial measures against soil liquefaction are reviewed briefly.