• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.10
• /
• pp.1145-1152
• /
• 2014

The RFID (Radio-Frequency Identification) system is a technology to discern things by radio and an epoch-making new method to improve product management such as distribution, transport, mobilization, inventory control. However, RFID, which uses radio, is at risk for information leakage and falsification due to the vulnerability of security of the communication section. We designed the new authentication protocol by applying the tent map, which is the representative complex systems, to the RFID communication system. A more solid and simple authentication system was designed by applying the initial value sensitivity and irregularity, which are the representative characteristics of the complex system, to the reader and tag of RFID. The purpose of this paper is to verify the usability of the RFID authentication protocol design that uses the nonlinear system shown in this thesis by the new system differentiated from the authentication system that depends on the existing hash function or random numbers.

• Horticultural Science & Technology
• /
• v.17 no.4
• /
• pp.467-469
• /
• 1999

This study was conducted to examine the changes of nutritive substances in the edible potato varieties ('Superior', 'Atlantic', 'Irish Cobbler', 'Dejima') during storage under low temperature condition($4^{\circ}C$, 85-90% RH) from January to May. The items examined in this experiment were moisture, free soluble sugars, starch and vitamin C. The contents of starch and vitamin C decreased with increasing storage period. The rates of decrease in starch and vitamin C contents were high in February and low after that. The contents of moisture and free soluble sugars did not show a constant tendency during storage period. The contents of glucose and fructose were the highest in February and March. Among the four varieties, 'Superior' contained highest vitamin C, free sugar, and moisture, while 'Atlantic' contained the highest starch.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.23 no.1
• /
• pp.93-100
• /
• 2011

A coupled tide-surge model, which has been evaluated the utility in the previous study, is applied for simulating the inundation phenomena. The coupled model system adopts the hydrodynamic module of MIKE21 software, and the study area is identical to the previous study. The only difference is additional detailed areas for simulating inundation. An artificial scenario of a virtual typhoon striking Mokpo coastal zone at spring high tide is simulated. Then the calculated water level corresponds to the extreme high water level(556 cm) for 100 year return period. The result also shows the inundation depth is 50~100 cm not only near the Mokpo Inner Port but also near the Mokpo North Port. Finally, the coastal inundation prediction map is drawn on the basis of inundation simulation results.

• Journal of Soil and Groundwater Environment
• /
• v.21 no.6
• /
• pp.192-203
• /
• 2016

A field investigation was conducted on an aquifer contaminated with trichloroethylene (TCE) for application of in situ reactive zone treatment using nanosized zero-valent iron (NZVI). The aquifer was an unconfined aquifer with a mean hydraulic conductivity of $5.14{\times}10^{-4}cm/sec$, which would be favorable for NZVI injection. Seasonal monitoring of TCE concentration revealed a presence of non-aqueous phase liquid form of TCE near IW (injection well). The hydrochemical data characterized the site groundwater to be a $Ca-HCO_3$ type. The average value of Langelier Saturation Index of the groundwater was -1.33, which implied that the site was favorable for corrosion of NZVI. Dissolved oxygen (DO) concentration varied between 2.5~11.5 mg/L, which indicated that DO would greatly compete with TCE as an electron acceptor. The hydrogeological and hydrochemical characterization reveals that the time around November would be appropriate for NZVI injection when water level and temperature are relatively high and DO concentration is low.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.3
• /
• pp.321-331
• /
• 2013

This paper describes the evaluation of shield TBM disc cutter penetration depth in practice. In this study the disc cutter penetration depth used to design the excavation speed of tunnel is reviewed. The characteristics of ground encountered in the investigation site are analysed and evaluated. The shield TBM used in the field is reviewed to verify the applicability of machine in the site. The thrust and torque capacities of each TBM disc cutter are also evaluated. Based on the field data, the excavation volume and speed are re-analysed to evaluate the disc cutter penetration depth used in the design stage. It is clearly found that the design value of disc cutter penetration depth needs to modify when estimation of the TBM capacities in very hard rock formation ($S_c$ >150 MPa).

• Smart Structures and Systems
• /
• v.25 no.4
• /
• pp.433-446
• /
• 2020

In this paper the effect of confining pressure and tunnel depth on the ground vertical settlement has been investigated using particle flow code (PFC2D). For this perpuse firstly calibration of PFC2D was performed using both of tensile test and triaxial test. Then a model with dimention of 100 m × 100 m was built. A circular tunnel with diameter of 20 m was drillled in the middle of the model. Also, a rectangular tunnel with wide of 10 m and length of 20 m was drilled in the model. The center of tunnel was situated 15 m, 20 m, 25 m, 30 m, 35 m, 40 m, 45 m, 50 m, 55 m and 60 m below the ground surface. these models are under confining pressure of 0.001 GPa, 0.005 GPa, 0.01 GPa, 0.03 GPa, 0.05 GPa and 0.07 GPa. The results show that the volume of colapce zone is constant by increasing the distance between ground surface and tunnel position. Also, the volume of colapce zone was increased by decreasing of confining pressure. The maximum of settlement occurs at the top of the tunnel roof. The maximum of settlement occurs when center of tunnel was situated 15 m below the ground surface. The settlement decreases by increasing the distance between tunnel center line and measuring circles in the ground surface. The minimum of settlement occurs when center of circular tunnel was situated 60 m below the surface ground. Its to be note that the settlement increase by decreasing the confining pressure.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.10 no.3
• /
• pp.199-208
• /
• 2012

To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.255-259
• /
• 2003

The technique of birdeye image generation of terrain through the use of satellite digital images and digital maps are very important elements and have applications in planning establishment as well as the actual design of several construction work in complex fields. This paper studies stereo perspective image generation as a possibility through 3-dimensional analysis combined with digital elevation data and remotely sensed images. For this, first of all, ortho-images generated by very accurate GCP and DEM from contour file makes 3-dimensional terrain analysis possible and allows stereo-viewing at the highway construction planning sites. So, we developed the technical methods for the 3-dimensional approach on the planning sites of highways by use of perspective orthoimages. From this research diverse terrain analysis is possible through stereo perspective image generation, and can leads to various application in road construction through gain study results from access to realtime virtual spatial on the objects area in korea.

• Journal of Korean Society for Geospatial Information Science
• /
• v.12 no.4 s.31
• /
• pp.69-74
• /
• 2004

By the expanding of infrastructure caused by urbanization, new technologies are required to manage various kinds of facilities. GIS has been appraised as valuable technology for facilities management since the 1990s. Therefore, the long and mid term GIS construction plan has been established by the national government and the local government. Some facilities management systems have been built and developed for suppling user-friendly functions. From this point of view, the information system based on the video sequences is considered a more effective way to improve the defects of conventional GIS using the digital map or the image as the base map. Using the video sequences as a base map, the availability of the system ill be increased because the real world information can be furnished to the users. In this study, through the connection between the GIS data, the digital map and the attribute data, and the video sequences taken from the airship using the video geo-referencing and the object tracking, we developed the facilities management system as a prototype which can effectively manage the road utilities. We also presented potentialities of the suggested system for facility management based on the video sequences.

• Journal of Advanced Navigation Technology
• /
• v.24 no.2
• /
• pp.92-100
• /
• 2020

Satellite-based argumentation systems (SBAS) is a system that enhances the accuracy, integrity, availability and continuity of GNSS navigation users by using geostationary orbit (GEO) satellites to send correction information and the failures of global navigation satellite system (GNSS) satellites in the form of messages. The correction information provided by SBAS is pseudorange error, satellite orbit error, clock error, and ionospheric delay error at 250 bps. Therefore, A lot of message processing are required for the SBAS navigation. There is a need to reduce SBAS time to first fix (TTFF) for using SBAS navigation in systems with short operating time. In this paper, A-SGNSS operation method was proposed for reducing SBAS TTFF. Also, A-SGNSS TTFF and availability were analyzed.