• Spatial Information Research
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• v.13 no.1 s.32
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• pp.55-63
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• 2005

Direct Georeferencing(DG) Is based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The methods can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. Hence, as long as securing Digital Elevation Model (DEM), it is feasible to generate digital orthophotos without performing the aerial triangulation with Ground Control Point (GCP) surveying. In this study, the DEM is automatically generated by using a image matching technique based on aerial photos and exterior orientation parameters. This is followed by producing an orthophoto from these results. Finally, accuracy analysis of the georeferencing technique for generating orthoimage indicates that RMS errors of 62cm and 76cm occurred at the X and the Y axis, respectively. This means that the results fulfill the demanding accuracy of the 1:5000 digital map. Hence, it is possible to conclude from this study that the direct georeferencing based orthoimage generation method is able to effectively digital map update.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.125-133
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• 2011

For any pattern matching based algorithm in WLAN environment, the characteristics of signal to noise ratio(SNR) to multiple access points(APs) are utilized to establish database in the training phase, and in the estimation phase, the actual two dimensional coordinates of mobile unit(MU) are estimated based on the comparison between the new recorded SNR and fingerprints stored in database. As fingerprinting method, k-nearest neighbor(KNN) has been widely applied for indoor location in wireless location area networks(WLAN), but its performance is sensitive to number of neighbors k and positions of reference points(RPs). So intuitive fuzzy c-means(IFCM) clustering algorithm is applied to improve KNN, which is the KNN/IFCM hybrid algorithm presented in this paper. In the proposed algorithm, through KNN, k RPs are firstly chosen as the data samples of IFCM based on signal to noise ratio(SNR). Then, the k RPs are classified into different clusters through IFCM based on SNR. Experimental results indicate that the proposed KNN/IFCM hybrid algorithm generally outperforms KNN, KNN/FCM, KNN/PFCM algorithm when the locations error is less than 2m.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.109-115
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• 2011

As fingerprinting method, k-nearest neighbor(KNN) has been widely applied for indoor location in wireless location area networks(WLAN), but its performance is sensitive to number of neighbors k and positions of reference points(RPs). So artificial neural network(ANN) clustering algorithm is applied to improve KNN, which is the KNN/ANN hybrid algorithm presented in this paper. For any pattern matching based algorithm in WLAN environment, the characteristics of signal to noise ratio(SNR) to multiple access points(APs) are utilized to establish database in the training phase, and in the estimation phase, the actual two dimensional coordinates of mobile unit(MU) are estimated based on the comparison between the new recorded SNR and fingerprints stored in database. In the proposed algorithm, through KNN, k RPs are firstly chosen as the data samples of ANN based on SNR. Then, the k RPs are classified into different clusters through ANN based on SNR. Experimental results indicate that the proposed KNN/ANN hybrid algorithm generally outperforms KNN algorithm when the locations error is less than 2m.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.215-220
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• 2016

In this paper, a wideband antenna accomplished by adding a double sleeve of a rectangular planar monopole structure is proposed. In order to impedance matching of proposed antenna, the antenna performance was improved by adding two gap sleeves and outer sleeve for double sleeve structure. HFSS simulator of ANSYS corp. was used in order to confirm the antenna parameter characteristic. According to the simulation results, the VSWR was less than 2 for the range of 2.5GHz~10.5GHz. The frequency bandwidth is 8GHz. The frequency range of the actual fabricated antenna was 2.92GHz~10.32GHz, the frequency bandwidth is 7.4GHz. The measured radiation pattern frequency is 3GHz, 6GHz and 9GHz. The results are similar with dipole antenna pattern in all frequency. The antenna size is $40{\times}40mm^2$. The utilization possibility of the ultra-wideband planar monopole antenna could be confirmed according to compare and analyze the simulation and measurement data.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.35-43
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• 2013

Georeferenced SLI(Street-Level Imagery) services such as Google Streetview, which contain abundant information about the real world, can increase its applicability substantially through conflation with other spatial datasets. For this purpose, we propose a method to improve a correspondence of building region to combine building information more accurately. First, the spatial inconsistency between SLI and vector map is removed by alignment based on road intersections. Then, visible building regions are searched from the spatial inconsistency-removed vector map, and the optimal corresponding building areas are determined in the SLI scene using the visible regions as seed information. The experimental results demonstrated that our method had improved the accuracy of building region correspondence by about 8%. Therefore, our method can be utilized effectively for enhancement of conflation service based on the SLI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.1000-1006
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• 2014

This study focuses on the fact that a OTT service is vigorously used for smart phones, and suggests a design of method to trace the experiences of watching television contents. For this purpose, we developed logging functions and embedded them into existing OTT service application to record flow and pattern of watching context. This paper suggests a log file format which can accurately and precisely record watching actions of users per-second methodology rather than former per-minute methodology. Moreover, this study shows that the application can trace watching attitude according to occurring events by characteristics and playing modes of realtime broadcasting, VOD, advertisement contents. In addition, based on the result of the study, this paper discusses educational, operational meaning of the method such as methodological application in mobile ethnography field or survey for total screening rate.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.319-322
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• 2013

Image retrieval research activity has moved its focus from global descriptors to local descriptors of feature point such as SIFT. MPEG is Currently working on standardization of effective coding of location and local descriptors of feature point in the context mobile based image search driven application in the name of MPEG-7 CDVS (Compact Descriptor for Visual Search). The extracted feature points consist of two parts, location information and Descriptor. For efficient image retrieval, we proposed a novel method that is gradual block-based efficient lossy location coding to compress location information according to distribution in images. From experimental result, the number of average bits per feature point reduce 5~6% and the accuracy rate keep compared to state of the art TM 3.0.

• Journal of IKEEE
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• v.24 no.3
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• pp.791-796
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• 2020

In this paper, "Q-Bone", a 3^rd generation blockchain platform with enhanced security and flexibility, was developed. As a 3^rd generation blockchain platform, it exploits BP (block producer) to increase processing speed. It has many advantages as follows. It improves both security and speed by mixing RSA (Rivest-Shamir-Adleman) and AES (advanced encryption standard). It improves flexibility by exploiting gateway to convert between apps and blockchain with different programming language. It increases processing speed by combining whole transactions into one block and distribute it when too many transactions occur. It improves search speed by inserting sequence hash into transaction data. It was implemented and applied to pet communication service and academy-instructor-student matching service, and it was verified to work correctly and effectively. Its processing speed is 3,357 transactions/second, which shows excellent performance.

• KIISE Transactions on Computing Practices
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• v.21 no.2
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• pp.138-143
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• 2015

The Boyer-Moore algorithm is a single pattern string matching algorithm that is widely used in various applications such as computer and internet security, and bioinformatics. This algorithm is computationally demanding and requires high-performance parallel processing. In this paper, we propose a parallelization and performance optimization methodology for the BM algorithm on a GPU. Our methodology adopts an algorithmic cascading technique. This results in significant reductions in the mapping overheads for the threads participating in the parallel string matching. It also results in the efficient utilization of the multithreading capability of the GPU which improves the load balancing among threads. Our experimental results show that this approach achieves a 45-times speedup at maximum, in comparison with a serial execution.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.217-222
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• 2017

Recent studies for working robot in dangerous places have been carried out on large unmanned ground vehicles or 4-legged robots with the advantage of long working time, but it is difficult to apply in practical dangerous fields which require the real-time system with high locomotion and capability of delicate working. This research shows the collaborated docking system of drone and ground vehicles which combines image processing algorithm and laser sensors for effective detection of docking markers, and is finally capable of moving a long distance and doing very delicate works. We proposed the docking system of drone and ground vehicles with sensor fusion which also suggests two template matching methods appropriate for this application. The system showed 95% docking success rate in 50 docking attempts.