• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.51-60
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• 2003

The watermarking is the technique that embeds or extracts the certain data without the change of the original data for the copyright protection of the multimedia contents. Watermark-embedded contents must not be distinguished by human's eye and must be robust to the various image processing and the intentional distortions. In this paper, we propose a new watermarking technique applied in the wavelet domain which has both the spatial and frequency information of a image. For both the robustness and the invisibility, the positions for embedding the watermark is selected with the multi-threshold. We search the similarity between highly correlated coefficients in the each subband and decide the mark space after verifying the significance in the specified subband. The similarity is represented by the coefficient difference between the subbands and its distribution is used in the watermark embedding and extracting. The embedded watermark can be extracted without the original image using the relationship of the subbands. By these properties the proposed watermarking algorithm has the invisibility and the robustness to the attacks such as JPEG compression and the general image processing.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1779-1785
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• 2018

In this paper, we propose an error correction method to improve the accuracy of human activity recognition using sensor event data obtained by smart devices such as wearable and smartphone. In the context awareness through the smart device, errors inevitably occur in sensing the necessary context information due to the characteristics of the device, which degrades the prediction performance. In order to solve this problem, we apply Kalman filter's error correction algorithm to compensate the signal values obtained from 3-axis acceleration sensor of smart device. As a result, it was possible to effectively eliminate the error generated in the process of the data which is detected and reported by the 3-axis acceleration sensor constituting the time series data through the Kalman filter. It is expected that this research will improve the performance of the real-time context-aware system to be developed in the future.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.12
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• pp.41-50
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• 1999

In this paper, the new VLSI architecture of a reconstruction filter for morphological image segmentation is proposed. The filter, based on the $h_{max}$ operation, simplifies the interior of each region while preserving the boundary information. The proposed architecture adopts a partitioned memory structure and an efficient image scanning strategy to reduce the operations. The proposed memory partitioning scheme makes it possible that every data required for processing can be read from each memory at a time, resulting in parallel data processing. By the extended connectivity consideration, the operation is much decreased because more simplification is achieved in scanning stage. The selective raster scan strategy endows the satisfactory noise removal capability with negligible hardware complexity increase. The proposed architecture is designed using VHDL, and functional evaluation is performed by the CAD tool, Mentor. The experiment results show that the proposed architecture can simplify image profile with less than 18% operations of the conventional method.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.433-440
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• 2013

The Ministry of Land, Infrastructure and Transport was developed the Construction CALS system for improvement of the construction economy. Construction CALS system is consist by Construction Portal System, Construction Management System, Construction Authorization and Permission System, Compensation Management System, Facility Maintenance Management System and has utilized at construction site of more than 900. Ministry of Land, Infrastructure and Transport and related researcher was proposed method of various function improvements for usability of the system. However, the proposed method was expanded the problems like increase of system management cost and development cost with decrease of data process rate. The problem was increases because has added of only service function without modify of software structure to the system on each different platform base. One of the methods for solving problems is to apply the e-Government framework and then integrated the different platform. The purpose of this paper is analyse of the applicability and efficiency of e-Government framework to the construction CALS system. For that was analyzed the e-Government standard framework and the developments case. And then was verified about the adaption possibility and efficiency by use the Function Point tool.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.367-374
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• 2018

A trajectory-based scheduling system is proposed for air traffic management using next generation aviation data communication link. Based on the service concept of 4-dimensional trajectory data link (4DTRAD) using air traffic serveices (ATS) datalink Baseline 2, a procedure for trajectory-based operation of an en-route flight is established and described in detail. To mitigate air traffic controllers' workload which might be caused by various and complicated data utilization, a prototype of the scheduling system, which predicts the aircraft trajectory based on the flight intents received by air traffic service system and provides advisory information for air traffic control, was developed. The simulation environment for trajectory based operation was built to validate the scheduling functionality of the prototype.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.538-547
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• 2004

Optical Burst Switched (OBS) networks usually employ one-way reservation by sending a burst control packet (BCP) with a specific offset time, before transmitting each data burst frame (BDF). Therefore, The quality of service may be degraded because contentions may lead to loss of BDFs. Especially, this phenomenon becomes more serious when burst size is longer. This necessitates an effective method of prevention to avoid burst collision in nodes. OBS networks can employ several methods to avoid such burst losses. One is that burst size is cut short to reduce burst loss probability during scheduling time. In this paper, we evaluate the burst generation and transmission using Sub-Carrier Multiplexting (SCM) in OBS networks. We propose an appropriate burst assembly architecture and transmission scheme based on SCM in OBS networks. The performance of SCM in OBS networks is examined in terms of number of Sub-Carriers per wavelength, burst loss probability, throughput, and total bandwidth of an optical fiber.

• Journal of the Korean Geophysical Society
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• v.10 no.1
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• pp.37-44
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• 2007

Nowadays, Global Navigation Satellite System(GNSS) which is the new concept of positioning system has been developed because of satisfaction human's intelligent desire and rapid science development. GNSS which is represented by GPS provides 3-Dimension positioning information not expensively in whenever, wherever. The industry of positioning information has extending civil market widely as well as military market. So GNSS is running the role of society infra structure including car and airborne navigation, civil engineering, GIS resource, telematics and LBS, and so on. As USA removes the SA(Selective Availability), GPS has monopolizing the market and other countries have been depended on GPS, absolutely. In this paper, the author developed the software for analysis of influence using next generation, Galileo system. The local analysis was performed according to positioning mode. And GPS/Galileo combined system can implement positioning in the worst mask environment like urban cannon.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.217-225
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• 2017

A study proposes possibility of new IoT measuring system blended with a smart device. The research serves the best cultivation information for domestic fruit's enhancement of competitive power and also develops a glucose measuring system by which people manage fructose with the mobile device. The mobile glucose tester is designed with a form of accessory which has high portability and utility because the product connects an existing analogy refractometer to the smart phone. You can check the glucose rates data by commodity, region, and season then save measurement results with server in real time for an exclusive application. It's possible to serve the glucose map, graph, and data list through the web service. This is very useful to do collect, analyze, and process the glucose data.

• Journal of Convergence for Information Technology
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• v.10 no.2
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• pp.32-38
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• 2020

In this paper, we analyze the modulation scheme for high speed transmission in visible light communication system, and study non-orthogonal multiplexing, dimming level and transmission power ratio. Conventional visible light communication has a disadvantage in that it is difficult to multi-transmit to increase the transmission speed. Multi-transmission technique is necessary for high-speed transmission at the transmitter. Since general visible light communication has a limitation in multiple transmission, various researches for high-speed transmission have been conducted. In order to solve this problem, this paper proposes a multiple modulation scheme for high-speed visible light communication using non-orthogonal multiplex transmission scheme and a future research direction.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.9-15
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• 2020

Wireless sensor nodes adopting the advanced preamble detection function, Message-In-Mesage (MIM), maximize the concurrent transmission opportunities due to the capture effect, result in improving the system performance significantly compared to the legacy IEEE 802.15.4 based sensor devices. In this paper, we propose an MIM capture probability model to analyze the performance gains by applying the MIM function to the wireless sensor nodes. We implemented the IEEE 802.15.4 and MIM by Python and performed extensive simulations to verify the performance gains through MIM capture effects. The evaluation results show that the MIM sensors achieve 34% system throughput gains and 31% transmission delay gains over the legacy IEEE 802.15.4-based sensors, which confirm that it was consistent with the analysis result of the proposed MIM capture probability model.