• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.252-263
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• 2016

Road sign is an important street furniture that gives some information such as road conditions, driving direction and condition for a driver. Thus, road sign is a major target of image recognition for self-driving car, ADAS(autonomous vehicle and intelligent driver assistance systems), and ITS(intelligent transport systems). In this paper, an enhanced road sign recognition system is proposed for MMS(Mobile Mapping System) using the single camera and GPS. For the proposed system, first, a road sign recognition scheme is proposed. this scheme is composed of detection and classification step. In the detection step, object candidate regions are extracted in image frames using hybrid road sign detection scheme that is based on color and shape features of road signs. And, in the classification step, the area of candidate regions and road sign template are compared. Second, a Geo-marking scheme for geo-content that is consist of road sign image and coordinate value is proposed. If the serious situation such as car accident is happened, this scheme can protect geographical information of road sign against illegal users. By experiments with test video set, in the three parts that are road sign recognition, coordinate value estimation and geo-marking, it is confirmed that proposed schemes can be used for MMS in commercial area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2345-2351
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• 2013

LBS(Location Based System) usually uses GPS technology to measure the exact position of the moving object. However, the method of managing location which utilizes the WiFi technology of mobile phone has not been introduced so far. The method of managing moving objects in view of the location of guardian has also not been proposed. In this paper, a new location management system of moving objects which take guardian's location into consideration is proposed. Specifically, the three methods of searching for missing child proposed in this paper are as follows : 1) a method based on an app for smart phone, 2) a method based on control server, 3) a method based on control server and fixed APs. Because the proposed system reflects the location of the guardian, the guardian is able to identify the state of child immediately and the workload can be reduced.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.1025-1031
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• 2007

GPS is widely used for positioning applications and attitude of a vehicle can be found also with multiple antennas. However, extremely weak signal level prevents GPS from indoor operation. DR with accelerometers and gyros and landmark based localization method used for indoor applications increase complexity and cost. In this paper, a simple but very efficient ultrasound based attitude determination system which determines both position and attitude in WSN is given. The range between transmitter and receivers are measured using the arrival time difference between ultrasound and RF signal. The 3 dimensional positions can be found using more than 3 range measurements. Furthermore, if more than 2 transmitters are used, the attitude can be determined using the baseline vectors obtained by differencing transmitter and receiver positions. The prototype system is implemented to evaluate the performance of the proposed method. In addition, an error analysis shows the relation between the attitude error and basel me length, quality of measurement and orientation of a vehicle. The static and dynamic experiments performed by micro mobile robot shows accurate position with less than 1.5cm error and attitude with less than 1 degree error can be obtained continuously with 20cm baseline. It is expected that these results can be adapted without modification to indoor applications such as home cleaning robot and autonomous wheelchair maneuvering.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.51-56
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• 2014

Thesedays, there are many smart device applications developed, especially on the using various sensors included in the smart device. Smart devices have several sensors which are camera, GPS, mike, and communication module for collecting ubiquitous environment, and many applications are developed by using such sensors. In this paper, we developed the multimedia stream architecture and examined the smart device applications based on open source with front and back-end server clouds for developing the conceptual architecture. Also, we examined the back-end distributed servers, realtime multimedia stream transferring, multi-media store, and media relay for other server and smart devices. We test the examined architecture on the real target environment to collect the SIP initial setup time, media stream delay, and end-to-end play time. The test results show that there have good network operation environment to provide realtime multimedia services, and we need to improve the end-to-end play time by minimizing the initial setup time.

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.77-89
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• 2005

Recently, application area on the Location Based System(LBS) is increasing because of development of mobile-communication and GPS technique. Previous studies on the index of moving objects are classified as either index for past trajectories or current/future positions. It is necessary to develop a unified index because many applications need to process queries about both past trajectories and current/future positions at the same time. In this paper, the past trajectories of moving objects are represented as line segments and the current and future positions are represented as the function of time. We propose a new index called PCR-tree(Past, Current R-tree) for unification of past, current and future positions. Nodes of the index have bounding boxes that enclose all position data and entries in the nodes are accessed with only one interface. We implement the proposed index and show a feasibility of processing the queries about temporal-spatial domain with the query tool which we develop.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2183-2190
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• 2013

Container Security Device (ConTracer) which is suggested in this study is to monitor temperature, humidity, and impact inside of the container while the container is transported. ConTracer could also give information to users when a door of the container is opened over 2 inch within 1 second. Additionally, GPS/GLONASS based global position and status information about container are transmitted to a remote server using IoT (Internet of Things) based communication. In this research, we are looking into the development trend of global container security devices; and applying ConTracer to real freight transport from domestic to overseas using Global Roaming Service which is offered for domestic Mobile Communication Companies as well. As a result, we estimate the performance of ConTracer and verify it.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.533-538
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• 2017

In this thesis, the ambulatory aid mechanism was implemented so that blind people could be safer at risk of walking outdoors. Using ultrasonic sensors, the obstacles can be detected when the distance between the obstacle is within 50 cm of the obstacle. If the light sensor becomes less than 25 lux, the LED will automatically turn on and help the safety of the visually impaired and the security of sight of the peripheral walkers. Color recognition sensors increase the rate of recognition of yellow color by the detection distance is 1cm, it vibrated when yellow light was detected. Using GPS with 7.3 m of error range, the guardian was able to check the location of the visually impaired.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.133-139
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• 2012

Currently, we are living in the world of invisible radio waves with a variety of frequencies. As today's society is rapidly changing to an era of wireless communication, the importances of antenna(especially, small patch antenna) are increasing according to the coming of wireless mobile communication society. In this paper, we design a small patch antenna which can support the functions of DMB and GPS through devices like cellular phone. The main feature and contribution of the designed patch antenna are as follows. First, the patch antenna is designed by HFSS and the ceramic materials for the patch antenna is utilized. Second, we obtain the patch antenna with reduced size and increased profit of reception, and the designed patch antenna can be applied for small devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2177-2184
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• 2012

A different and effective method for indoor positioning system is needed and increased it's importance compare to the outdoor GPS based method. The FingerPrint positioning method is known as a superior method in indoor positioning system that maintains signal strength patterns for RPs(Reference Points) in database and compare the DB with the measured real-time signals on the mobile device. FingerPrint positioning method is necessary to establish an accurate database, but errors can occur by several factors. In this paper, we analyze the signal patterns of each terminal in accordance with connection state of access point and trace that the error in accordance with connection state of access point can be an important error in FingerPrint DB configuration through an experimental case study.

• Journal of IKEEE
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• v.14 no.3
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• pp.224-231
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• 2010

Automatic detection of objects in images has been one of core challenges in the areas such as computer vision and pattern analysis. Especially, with the recent deployment of personal mobile devices such as smart phone, such technology is required to be transported to them. Usually, these smart phone users are equipped with devices such as camera, GPS, and gyroscope and provide various services through user-friendly interface. However, the smart phones fail to give excellent performance due to limited system resources. In this paper, we propose a new scheme to improve object recognition performance based on pre-computation and simple local features. In the pre-processing, we first find several representative parts from similar type objects and classify them. In addition, we extract features from each classified part and train them using regression functions. For a given query image, we first find candidate representative parts and compare them with trained information to recognize objects. Through experiments, we have shown that our proposed scheme can achieve resonable performance.