• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1082-1088
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• 2005

Generating fast round key in AES Rijndael algorithm using three key sizes, such as 128, 192, and 256-bit keys is a critical factor to develop high throughput AES processors. In this paper, we propose on-the-fly round key generator which is applicable to the pipelined and non-pipelined AES processor in which cipher and decipher nodes must be implemented on a chip. The proposed round key generator has modular and area-and-time efficient structure implemented with simple connection of two key expander modules, such as key_exp_m and key_exp_s module. The round key generator for non-pipelined AES processor with support of three key lengths and cipher/decipher modes has about 7.8-ns delay time under 0.25um 2.5V CMOS standard cell library and consists of about 17,700 gates.

• Journal of the Korea Institute of Building Construction
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• v.10 no.3
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• pp.65-70
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• 2010

Steel frame construction in high places entails many risk factors. In order to improve the safety and productivity of steel frame construction, a project to develop a robotic tower-crane has been undertaken. As the first step, a real-time lifting-path tracking system is being developed. In a previous study, a laser-based tracking system was proposed. While a laser-based tracking system requires at least three laser sensors to detect the x, y, z coordinates of a lifted steel member, a GPS-based system has an advantage over the laser-based system, in that the x, y, z coordinates of a lifted steel member can be detected by a single GPS sensor. To improve the accuracy, arelative positioning method using two GPS sensors was proposed in a previous study. This paper reports an improved GPS-based lifting-path tracking system of a tower crane based on an integrated RF modem and GPS system. The results showedthat the RF modem could successfully send the identifier information to a server a maximum distance of 1 km away from the lifted steel beam, and the lifting path information of each beam captured by the GPS-based tracking system was successfully saved together. Also, byusing an improved algorithm for the GPS relative positioning method, the deviation was reduced to 0.61 m on average.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.251-258
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• 2007

Airborne Lidar (light detection and ranging) can be an effective alternative in forest inventory to overcome the limitations of conventional field survey and aerial photo interpretation. In this study, we attempt to develop methodologies to identify individual trees and to estimate tree height from airborne Lidar data. Initially, digital elevation model (DEM) data representing the exact ground surface were generated by removing non-ground returns from the multiple-return laser point clouds, obtained over the coniferous forest site of rugged terrain. Based on the canopy height model (CHM) data representing non-ground layer, individual tree heights are extracted through pseudo-grid method and moving window filtering algorithm. Comparing with field survey data and aerial photo interpretation on sample plots, the number of trees extracted from Lidar data show over 90% accuracy and tree heights were underestimated within 1.1m in average at two plantation stands of pine (Pinus koraiensis) and larch (Larix leptolepis).

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.1
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• pp.56-63
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• 2003

This paper introduces a vision based autonomous mini mobile robot that is an approach to produce real autonomous vehicle. Previous autonomous vehicles are dependent on PC, because of complexity of designing hardware, difficulty of installation and abundant calculations. In this paper, we present an autonomous motile robot system that has abilities of accurate steering, quick movement in high speed and intelligent recognition as a stand-alone system using a mono camera. The proposed system has been implemented on mini track of which width is 25~30cm, and length is about 200cm. Test robot can run at average 32.9km/h speed on straight lane and average 22.3km/h speed on curved lane with 30~40m radius. This system provides a model of autonomous mobile robot adapted a lane recognition algorithm in odor to make real autonomous vehicle easily.

• Fire Science and Engineering
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• v.27 no.5
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• pp.15-18
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• 2013

This paper is concerned with the Performance and Reliability Certification for fire detection system in outdoor area such small and middle sized cultural assets, natural monument and outdoor facilities. Especially, if a fire were to occur in vulnerable area, it is difficulty to detect a fire. therefore we propose a high efficiency and low cost unmanned fire detection system in capable of an early detection regardless spontaneously fire or firebug. for Adoption of Intelligent Fire Detection System with movable and unmanned function breaking from the existing Conventional Fire Detection System, this Range of R&D includes the Performance test, Function test, Field test, Flame Detection test and EMI/EMS Compliance test. the Result data of Performance test, Function test and Field test is generally good during 3 months. also we checked that thermal variation test and EMI/EMS compliance test are good result data within allowable range. As a result of general test, we verified improvement results that the measure distance of fire detection extend 75 m, the Power of waiting time increase 4 hours, the Power of operation time increase 3 days and the context awareness with video as well as sensors.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.174-185
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• 2005

This paper presents the design, fabrication, and testing results of a dual stage actuator system for a fine positioning of magnetic heads in magnetic disk drives. A novel rotary microactuator which is electrostatically driven and utilized as a secondary actuator was designed. The stator and rotor electrodes in the microactuator was revised to have the optimal shapes and hence produces much higher rotational torque compared with the conventional comb-shape electrodes. The microactuators were successfully fabricated using SoG(silicon on glass) processing technology, which is known as being cost-effective. The fabricated microactuator has the structural thickness of $45{\mu}m$ with the gap width of approximately $3{\mu}m$. The dynamic characteristic of microactuator/slider assembly was investigated, and its natural frequency and DC gain were measured to be 3.4kHz and 32nm/V, respectively. The microactuator/slider assembly was integrated into a HDD model V10 of Samsung Electronics Co. and a dual servo algorithm was tested to explore the tracking performance of dual stage actuator system where the LDV signals instead of magnetic head signals were used. Experimental results indicate that this system achieves the tracking accuracy of 30nm. This value corresponds to a track density of 85,000 track per inch(TPI), which is about 3 times greater than that of current hard disk drives.

• Journal of Internet Computing and Services
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• v.11 no.4
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• pp.23-32
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• 2010

In this paper, we first propose the security enhancing of authentication protocol for Hash based RFID tag, and then a digital Codec for RFID tag is designed based on the proposed authentication protocol. The protocol is based on a three-way challenge response authentication protocol between the tags and a back-end server. In order to realize a secure cryptographic authentication mechanism, we modify three types of the protocol packets which defined in the ISO/IEC 18000-3 standard. Thus active attacks such as the Man-in-the-middle and Replay attacks can be easily protected. In order to verify effectiveness of the proposed protocol, a digital Codec for RFID tag is designed using Verilog HDL, and also synthesized using Synopsys Design Compiler with Hynix $0.25\;{\mu}m$ standard-cell library. Through security analysis and comparison result, we will show that the proposed scheme has better performance in user data confidentiality, tag anonymity, Man-in-the-middle attack prevention, replay attack, forgery resistance and location tracking.

• The Journal of Engineering Geology
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• v.11 no.3
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• pp.255-267
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• 2001

A comparison study is performed to understand the coupling behavior of the thermal, hydraulic, and mechanical interactions in the vicinity of an underground radwaste repository, assumed to be located at a depth of 500 m, within a granitic rock mass with a 58$^{\circ}$ dipping fault passing through the roof-wall intersection of the repository cavern. The two dimensional universal distinct element code, UDEC is used for the analysis. The model includes a granitic rock meas, a canister with PWR spent fuels surrounded by the compacted bentonite inside a deposition hole, and the mixed bentonite backfilled in the rest of the space within a repository cavern. The coupling behavior of hydromechanical, thermomechanical, and thermohydromechanical interaction has been studied and compared. The effect of the time-dependent decaying heat, from the radioactive materials in PWR spent fuels, on the repository and its surroundings has been studied. A steady state flow algorithm is used for the hydraulic analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1029-1039
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• 2009

In this paper, the existing disparity aquisition algorithms were analyzed, on the bases of which a disparity generation technique that is superior in accuracy to the generation time was proposed. Basically it uses a pixel-by-pixel motion estimation technique. It has a merit of possibility of a high-speed operation. But the motion estimation technique has a disadvantage of lower accuracy because it depends on the similarity of the matching window regardless of the distribution characteristics of the texture in an image. Therefore, an enhanced technique to increase the accuracy of the disparity is required. This paper introduced a variable-sized window matching technique for this requirement. By the proposed technique, high accuracies could be obtained at the homogeneous regions and the object edges. A hardware to generate disparity image was designed, which was optimized to the processing speed so that a high throughput is possible. The hardware was designed by Verilog-HDL and synthesized using Hynix $0.35{\mu}m$ CMOS cell library. The designed hardware was operated stably at 120MHz using Cadence NC-VerilogTM and could process 15 frames per second at this clock frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.313-322
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• 2003

In this paper, the reverse link performance of imperfect power controlled cdma2000 cellular system that using array at a base station is analyzed, when MCGM beamforming algorithm and power control error is considered in shadowing. The blocking probability of the cdma2000 cellular system based on array parameters, E$\_$b//N$\_$0/ and interference statistics is calculated, and then the system capacity is calculated at a specific blocking probability. When the blocking probability is set 1 %, PCE(power control error) is 2 dB, M=2, 4, 8, 10, the capacity of cdma2000 is increased 2.3 ∼ 2.5 times higher than IS-95.