• Convergence Security Journal
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• v.10 no.3
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• pp.29-41
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• 2010

Survelliance and Reconnaissance Sensor Network(SRSN) which can collect various tactical information within battlefield in real time plays an important role in NCW environment, of sensor to shooter architecture. However, due to the resource-limited characteristics of sensor nodes and the intrinsic attributes of sensor network such as wireless communication, the SRSN may be vulnerable to various attacks compared to traditional networks. Therefore, in this paper, we propose a new group key management scheme to guarantee confidentiality, integrity, availability, and authentication during the operation of the SRSN. Proposed scheme generates and distributes the group key based on the topological characteristic of the SRSN and the probabilistic key sharing. The communication cost for distributing the group key is O(logn).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.299-305
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• 2016

It is require to design the next generation avionics system while considering applicability under open architecture where standerd communication module is used. In this situation, if the existing schemes cannot guarantee new requirement, new system development is demanded. In this paper, we present design, implementation, and testing procedure for message based middleware to support operational flight program on avionics. System architecture include mission computer (MC) and large area display (LAD) over standard socket communication based on reliable Ethernet. Finally, experimental results demonstrate that the proposed middleware can guarantee real-time with 20msec as well as reliability requirements with no lost packet.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.4
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• pp.283-289
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• 2018

Launch Acceptability Region(LAR) means an area for successfully hitting the target. And LAR should be calculated in real time on aircraft so that LAR can be seen by pilot. LAR can be changed by the launch condition of the bomb, the impact condition of the target, and the atmospheric condition at the time of flight of the bomb. In this paper, we propose the calculation method of LAR using Artificial Neural Network(ANN). The learning data was generated by changing each condition from existing LAR model, and LAR model was derived through ANN learning. We confirmed the accuracy of the new LAR model by comparing the difference between the result data of existing LAR model and the new LAR model. And we confirmed the possibility of real time calculation of the LAR model on the aircraft by comparing the calculation time.

• The Korean Journal of Financial Management
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• v.26 no.3
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• pp.103-138
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• 2009

In this article we examine a unique data set of intraday fair disclosure(FD) releases to shed light on market efficiency within the trading day. Specifically, this paper analyze the response of stock prices on fair disclosure disseminated in real-time through KIND(Korea Investor's Network for Disclosure) on Korea stock exchange during the period from January 2003 to September 2004. We find that the prices of stock experiences a statistically and economically significant increase beginning seconds after the fair disclosure is initially announced and lasting approximately two minutes. The stock price responds more strongly to fair disclosure on smaller firm but the response to fair disclosure on the largest firm stock is more gradual, lasting five minutes. We also examine the profitability of a short-term trading strategy based on dissemination of fair disclosure. After controlling for trading costs we find that trader who execute a trade following initial disclosure generate negative profits, but trader buying stock before initial disclosure realize statistically significant positive profit after two minute of disclosure. Summarizing overall results, our evidence supports that security prices on Korea stock exchange reflects all available information within two minutes and the Korea stock market is semi-strongly efficient enough that a trader cannot generate profits based on widely disseminated news unless he acts almost immediately.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.174-182
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• 2015

In this paper, we developed the small size RGB sensor that recognizes a long distance using a low-cost color sensor. Light receiving portion of the sensor was used as a camera lens for far distance recognition, and illuminating unit was increased the strength of the light by using a high-power white LED and a lens mounted on the reflector. RGB color recognition algorithm consists of the learning process and the realtime recognition process. We obtain a normalized RGB color reference data in the learning process using the specimens painted with target colors, and classifies the three colors using the Mahalanobis distance in recognition process. We apply the developed the RGB color recognition sensor to a prototype of the part classification system and evaluate the performance of its.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.108-113
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• 2011

In this paper, we propose a new method for robot navigation control through EMG and acceleration sensors which is attached to wrist. The method can remote control with intuitive motion like driving a car. It decide to control whether or not through EMG signal processing. And motion inferring through signal processing from acceleration sensor. Inferred motion is mapped to control command such as 'Forward', 'Backward', 'Left', 'Right'. Accuracy of each motions are over 99%. Control is capable naturally without time delay. Entire system has been implemented and we verified its utility through demonstration.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.179-201
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• 2012

Since 1993, M&A activities have been frequent in Liner shipping market. This study examines the effect of M&A on stock price reaction for acquiring firms listed on the market. The study covers the period from 1993 to 2009 and uses 61 daily closing prices of the acquiring firms before and after the M&A announcement day and is analyzed through the market-adjusted model in an event study. After calculating short-term performance using abnormal returns(AR) and cumulative average abnormal returns(CAR) before and after 30 days from the day of event, the results on the test show that the firm's values slightly increased through the M&A, but it does not attest to the statistical significance. In addition, this study investigates the AR difference between estimating windows and post-event windows for the 3 cases of each period before and after 30 days, 15 days, and 7 days from the event day to analyse the impact of M&A on the addition of acquiring firm's value. Our findings suggest that the M&A between Liner shipping companies is targeted for the long-term business strategy instead of the instant rise in the value of the firm involved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2403-2408
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• 2015

For image data the discrete cosine transform (DCT) has comparable energy compaction capability to Karhunen-Loeve transform (KLT) which is optimal. Hence DCT has been widely accepted in various image and video compression standard such as JPEG, MPEG-2, and MPEG-4. Recently some approximate DCT's have been reported, which can be computed much faster than the original DCT because their coefficients are either zero or the power of 2. Although the level of energy compaction is slightly degraded, the approximate DCT's can be utilized in real time implementation of image or visual compression applications. In this paper, an approximate 8-point DCT which contains 17 non-zero power-of-2 coefficients and high energy compaction capability comparable to DCT is proposed. Transform coding experiments with several images show that the proposed transform outperforms the published works.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.75-82
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• 2017

Recently, as the roles and utilization fields of UAV become more diverse, demand for high - level mission has been increasing. To solve this issue, researches on the operation of multiple small UAVs and related systems have been actively carried out. The multiple small UAVs based application system has a problem that the task complexity of control personnel increases because the control personnel must continuously control and manage several small UAVs. Hence, it is necessary to develop a software platform that can perform efficient control in order to employ a multiple small UAVs based application system successfully. In this paper, we propose an effective ground control software platform for application systems using multiple small UAVs. We first analyze the requirements for the software platform, and design and implement software based on the analysis. Simulation using the X-plane flight simulator shows that multiple flight data are effectively displayed and that the image data transmitted from many small UAVs are simultaneously displayed in real time.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.646-657
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• 2019

Objectives: The purpose of this study was to suggest methods to investigate continuous monitoring of concentration levels and assess the exposure of individuals considering the actual time activity of residents for formaldehyde and particulate matter (PM₁₀, PM_2.5) in the indoor and outdoor air of a house, assess the health risks of children and adults based on the results of the exposure assessment, and provide basic data on studies for assessing exposure and health risks in Korea in the future. Methods: The concentration levels of formaldehyde and particulate matter were measured in a family home in Gyeonggi-do Province from April 25 to July 31, 2019, using electrochemical sensors (formaldehyde) and light scattering sensors (PM₁₀, PM_2.5). Risk assessment by the duration of exposure by time activity was performed by dividing between weekdays and weekends, and indoors and outdoors. Results: The greatest level of carcinogenic risk from inhaling formaldehyde was indoors during the weekdays for both children and adults. For children, the risk was at 7.5 per approximately 10,000 people, and for adults, the risk was at 4.1 per approximately 10,000 people. PM₁₀ and PM_2.5 also showed the greatest values indoors during the weekdays, with children at 1.7 people and 1.4 per approximately 100 people, respectively, and adults at 8.2 per approximately 1,000 and 1.8 per approximately 100 people, respectively. Conclusions: The risks of formaldehyde, PM₁₀ and PM_2.5 were shown to be high indoors. Therefore, consideration of exposure assesment for each indoor pollutant and management of indoor air quality is necessary.