• Journal of Digital Contents Society
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• v.13 no.2
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• pp.235-245
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• 2012

This paper introduce a quiz game contents based on gesture interface. We analyzed the off-line quiz games, extracted its presiding components, and digitalized them so that the proposed game contents is able to substitute for the off-line quiz games. We used the Kinect camera to obtain the depth images and performed the preprocessing including vertical human segmentation, head detection and tracking and hand detection, and gesture recognition for hand-up, hand vertical movement, fist shape, pass and fist-and-attraction. Especially, we defined the interface gestures designed as a metaphor for natural gestures in real world so that users are able to feel abstract concept of movement, selection and confirmation tangibly. Compared to our previous work, we added the card compensation process for completeness, improved the vertical hand movement and the fist shape recognition methods for the example selection and presented an organized test to measure the recognition performance. The implemented quiz application program was tested in real time and showed very satisfactory gesture recognition results.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.154-161
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• 2010

The conning display which is located in the ship bridge shows the various important information such as ship position, ship speed, track data, rate of turn, thruster rpm so on, and is one of the IBSs(Integrated Bridge Systems). In this study, the survey was conducted for ten officers to find the importance and using frequency of the information which were displayed in the conning display. The results showed that the information of drift speed, ship speed, wind direction and wind force, rate of turn, sea water depth, ship position, heading, thrust rpm, alarm, rudder command and angle got high scores and it meant that these information were very important and high frequency of use during the navigation. The optimized contents arrangement in conning display was suggested based on importance and using frequency of information. The experiment using eye-tracking system was conducted to compare the performance time and error rate of nine different scenarios for suggested arrangement display and three other existing displays. The results showed that the suggested arrangement was the best in performance time and error rate. The scenario concerning the direction and speed of wind showed faster performance time and lower error rate than other scenarios. The movement of subject's eye tended to search from the center and to avoid the comer, called 'the comer effect.' It is expected that the results of this study could help for the bridge staff to grasp the sailing information easily and to cope with the given situations promptly.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.209-218
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• 2017

To propose a contents model for children's smart watch, this study interview 15mothers who have a child using smart watches. Most mothers purchase smart watches for children to warrant their security and manage their schedules, and they use them for sending a call or text to their children, tracking or managing children's location and schedule. Mothers were satisfied with a smart watch's function of communication and safety management, but dissatisfied learning-oriented contents and worrried about bad influenced on children development. Through in-depth interviews, this study propose a persona model for children's smart watch for enhancing parent-child interaction and physical cognitive language socioemotional convergence play contents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.274-281
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• 2006

Sensor network applications need synchronized time extremely such as object tracking, consistent state updates, duplicate detection, and temporal order delivery. This paper describes reliable time synchronization protocol (RTSP) for wireless sensor networks. In the proposed method, synchronization error is decreased by creating hierarchical tree with lower depth and reliability is improved by maintaining and updating information of candidate parent nodes. The RTSP reduces recovery time and communication overheads comparing to TPSN when there are topology changes owing to moving of nodes, running out of energy and physical crashes. Simulation results show that RTSP has about 20% better performance than TPSN in synchronization accuracy. And the number of message in the RTSP is $20%{\sim}60%$ lower than that in the TPSN when nodes are failed in the network. In case of different transmission range of nodes, the communication overhead in the RTSP is reduced up to 40% than that in the TPSN at the maximum.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.149-156
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• 2003

This paper presents an underwater hybrid navigation system for a semi-autonomous underwater vehicle (SAUV). The navigation system consists of an inertial measurement unit (IMU), an ultra-short baseline (USBL) acoustic navigation sensor and a doppler velocity log (DVL) accompanying a magnetic compass. The errors of inertial measurement units increase with time due to the bias errors of gyros and accelerometers. A navigational system model is derived to include the error model of the USBL acoustic navigation sensor and the scale effect and bias errors of the DVL, of which the state equation composed of the navigation states and sensor parameters is 25 in the order. The conventional extended Kalman filter was used to propagate the error covariance, update the measurement errors and correct the state equation when the measurements are available. Simulation was performed with the 6-d.o.f. equations of motion of SAUV in a lawn-mowing survey mode. The hybrid underwater navigation system shows good tracking performance by updating the error covariance and correcting the system's states with the measurement errors from a DVL, a magnetic compass and a depth senor. The error of the estimated position still slowly drifts in horizontal plane about 3.5m for 500 seconds, which could be eliminated with the help of additional USBL information.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.305-316
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• 2015

The GPS signal delays in troposphere, which are along the signal path between a transmitting satellite and GPS permanent station, can be used to retrieve the precipitable water vapor. The GPS remote sensing technique of atmospheric water vapor is capable of monitoring typhoon and detecting long term water vapor for tracking of earth’s climate change. In this study, we analyzed GPS precipitable water vapor variations during the heavy snowstorm event occurred in the Yeongdong area, 2014. The results show that the snowfall event were occurring after the GPS precipitable water vapor were increased, the maximum fresh snow depth was recorded after the maximum GPS precipitable water vapor was generated, in Kangneug and Wuljin, respectively. Also, we analyzed that the closely correlation among the GPS precipitable water vapor, the K-index and total index which was acquired by the upper air observation system during this snowstorm event was revealed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.129-137
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• 2019

This study was conducted to investigate the effects of underwater noise caused by pile driving during marine construction on fish. In this study, the three gray rockfish were released about 1 km away from the construction site of wind power generation on July 18, 2018 and traced using two acoustic telemetry techniques. The behavior of the fish was analyzed by calculating the moving distance, swimming speed and direction of the gray rockfish. In the results of the acoustic tracking using the ship, the rockfish moved about 2.11 km for about two hours at a speed of $0.28{\pm}0.14m/s$ (0.94 TL/s). The bottom depth of the trajectory of the rockfish was $1.0{\pm}0.6m$ on average. There was a significant directionality in swimming direction of the gray rockfish, and there was no significant correlation between the swimming direction and tidal current direction. Moving distance during 5 minutes (5MD) during pile driving and finishing operations between rock surface and bedrock were 0.94-0.96 times (76.0-77.0 m) and 1.81-2.73 times (146.0-219.5 m), respectively, compared with no pile driving. This study is expected to be used as a basic data of fish behavior research on underwater noise.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.261-266
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• 2019

The purpose of this study is to assess usage of floating action button, a component of Google's Material Design. Case studies were conducted to overview the component's current usage and qualities, followed by eye-tracking experiments and in-depth interviews conducted to 12 subjects. Results have shown that while floating button can promote an action by catching viewers' attention with its striking visual, users tend to look at top more, thus preferring top placement for interfaces. To give positive user experience, designers should consider factors such as the amount of content covered by the button, the way users interact with the application, etc. This study aims to provide proper guidelines for the component's application.

• Smart Media Journal
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• v.9 no.4
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• pp.44-51
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• 2020

Since the mid-to-late 1990s, there have obviously been many changes in the North Korean economy. Since the change has been more pronounced since Kim Jong Un took power in 2012, the purpose of the paper is to track the trend of economic policy by timing. In this paper, I use LDA Topic Modeling, a text-mining analyzer method, to analyze the economics journal "Economic Research," which is a representative literature in the economic field published in North Korea. An in-depth analysis of the "economic research," which has an unrivaled position as an economic journal produced in North Korea, can be said to be an essential task in tracking the reality, limitations facing the economy and alternatives that North Korean authorities are aware of. Through the "Economic Research," where various topics of debate on the North Korean economy are hidden, the North Korean leader's economic policy flow is examined and the contents of the "change" intended by the current Kim Jong-un regime are analyzed.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.687-694
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• 2022

In this paper, we proposed an autonomous vehicle platform that delivers goods to a designated destination based on the SLAM (Simultaneous Localization and Mapping) map generated indoors by applying the Visual SLAM technology. To generate a SLAM map indoors, a depth camera for SLAM map generation was installed on the top of a small autonomous vehicle platform, and a tracking camera was installed for accurate location estimation in the SLAM map. In addition, a convolutional neural network (CNN) was used to recognize the label of the destination, and the driving algorithm was applied to accurately arrive at the destination. A prototype of an indoor delivery autonomous vehicle was manufactured, and the accuracy of the SLAM map was verified and a destination label recognition experiment was performed through CNN. As a result, the suitability of the autonomous driving vehicle implemented by increasing the label recognition success rate for indoor delivery purposes was verified.