• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2195-2202
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• 2011

Recently, navigation system is used to inform users of vehicle location and driving direction, moving distance and so on. This navigation uses GPS sensor for current location determination. The GPS sensor will determinate current coordinates by using triangulation algorithm. This characteristic bring about that the GPS signal is not available in the shadow region such as tunnel and urban canyon. Moreover, Even though the signal is available, inherent positional error rate of the GPS often results in the dislocation of vehicle. To solve, these problems, a new positioning system is proposed in the paper. The System utilizes geomagnetic sensors of smartphone, speed information of CAN of vehicle though bluetooth and WiFi APs for GPS shadow area. The experimental test shadows that the proposed system using multiple data is able to determine the position of vehicle in GPS shadow areas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2446-2452
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• 2012

In order to meet the recently enhanced emission standards at home and abroad, it is necessary to develop the CRDI ECU control algorithm that users can adjust fuel injection timing and amount in response to their needs. Therefore, this study developed the simulator for knocking analysis that enables knocking discrimination and engine balance correction applicable to the ECU exclusive to the industrial CRDI engine. The purpose of this study is to provide the driver-oriented diagnostic service that enable drivers to diagnose vehicles directly by developing diagnostic devices for vehicles with ths use of the results of the developed simulator for knocing analysis according to the OBD-II standards. For this purpose, this study aims to improve the fuel efficiency of vehicles by proposing the S/W design method of the OBD-II diagnosis device that can provide real-time communcations with the use of wired system and bluetooth module as a wireless system to send and recevice automobile fault diagnosis signal and sensor output signal, and to suggest an improvement for engine efficiency by minimizing the generation of harmful exhaust gas.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.293-298
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• 2007

The aged are faced with increasing risk for falls. The aged have more fragile bones than others. When falls occur, it is important to detect this emergency state because such events often lead to more serious illness or even death. A implementation of PDA system, for detection of emergency situation, was developed using 3-axis accelerometer in this paper as follows. The signals were acquired from the 3-axis accelerometer, and then transmitted to the PDA through a Bluetooth module. This system can classify human activity, and also detect an emergency state like falls. When the fall occurs, the system generates the alarm on the PDA. If a subject does not respond to the alarm, the system determines whether the current situation is an emergency state or not, and then sends some information to the emergency center in the case of an urgent situation. Three different studies were conducted on 12 experimental subjects, with results indicating a good accuracy. The first study was performed to detect the posture change of human daily activity. The second study was performed to detect the correct direction of fall. The third study was conducted to check the classification of the daily physical activity. Each test lasted at least 1 min. in the third study. The output of the acceleration signal was compared and evaluated by changing various postures after attaching a 3-axis accelerometer module on the chest. The newly developed system has some important features such as portability, convenience and low cost. One of the main advantages of this system is that it is available at home healthcare environment. Another important feature lies in its low cost of manufacture. The implemented system can detect the fall accurately, so it will be widely used in emergency situations.

• Journal of Biomedical Engineering Research
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• v.37 no.3
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• pp.112-118
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• 2016

The neck pain is fairly common occurance. Forward head posture and text neck are poor postures which may be related with neck pain but the evidence is not enough. We developed the wearable sensor which can assess the head & neck posture in daily life. Microprocessor, Bluetooth low energy, and 3-axis accelerometer, rechargeable battery and vibratior for reminding are used to implement the wearable sensor. Real-time algorithm to parameterize the posture for one epoch is implemented which classifies the posture in the epoch into three classed; dynamic, static_good posture, and static_poor posture. Also the algorithm makes reminding to its wearer to give them the prolonged poor posture is detected. The mean error of measurement was 1.2 degree. The correlation coefficient between neck angle and craniovertebral angle was 0.9 or higher in all cases. With the pilot study on text neck syndrome was also quatified. Average of neck angle were 74.3 degree during the listening in the classroom and 57.8 degree during the smartphoning. Using the wearable sensor suggested, the poor postures of forward head posture and neck neck can be detected in real-time which can remind the wearer according to his/her setting.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.31-42
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• 2006

Context-awareness is a technology to facilitate information acquisition and execution by supporting interoperability between users and devices based on users' context. It is one of the most important technologies in ubiquitous computing. In this paper, we propose a middleware and a context server for dealing with context-awareness in ubiquitous Computing and implement an application system using them. The middleware proposed in our work plays an important role in recognizing a moving node with mobility by using a Bluetooth wireless communication technology as well as in executing an appropriate execution module according to the context acquired from a context server. In addition, the proposed context server functions as a manager that efficiently stores into a database server context information, such as user's current status, physical environment, and resources of a computing system. Finally, our application system implemented in our work one which provides a music playing service based on context information, and it verifies the usefulness of both the middleware and the context server developed in our work.

• Smart Media Journal
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• v.1 no.4
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• pp.52-58
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• 2012

In recent years the combination of IT and BT for U-Healthcare Medical Services has attracted popular attention as an alternative for solving health problems due to aging issue. Active oxygen as free radicals causes unstable state of the body resulting to other disease on which approximate 90% of the diseases are associated with active oxygen. The severity is even higher along with increasing age. Therefore, there is a need for systematic management of active oxygen saturation for the elderly and chronic patients. In this paper, the data about active oxygen measurements from the body measurement is sent to the data storage of medical facilities by the service provider. Medical information is measured by devices provided complying with the standard, support and information using Bluetooth communication. Users can check their health status themselves using the proposed system through 3G/4G mobile devices like smart phone to medical institutions in which the smart phone act as a gateway for medical data transferred from patient to medical institutions and vice versa. Users can get and experience a diagnosis and effective U-Environmental Health Services from Medical institutions anywhere using the proposed built system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.63-68
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• 2017

In this paper, Distance recognition measurement using distance calculation correction algorithm, was realization through LED dimming control. The calculation values for the RSSI average filtering and the RSSI feedback filtering were calculated and applied to reduce the error of the RSSI value measured from a long distance. It was confirmed that the RSSI values through the average filtering and the RSSI values measured by setting the coefficient value of the feedback filtering to 0.5 were ranged from -61 dBm to - 52.5 dBm, which shows irregular and high values decrease slightly as much as about -2 dBm to -6 dBm as compared to general measurements. A distance calculation correction algorithm to improve the accuracy was applied, which confirmed that as the distance increases, the range of errors decreases. In conclusion, unstable signals were corrected using the RSSI measurement result filtering, and the distance calculation correction algorithm was applied and performed to reduce the range of errors. In addition, RGB colors were implemented by LED to indicate the distance determination and the signal stability.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.31-40
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• 2017

The rise of eco-friendly personal electric mobility is a worldwide trend and the first Korean-made IT convergence electric skateboard, Youth Board, is developed to lead the trend. Youth Board is remotely controllable using either Youth Wearable Controller or Youth App through Bluetooth v4.0 communication, can speed up to 25 km/hr, and operating time is approximately 1.5 hr. A LED display located in the front side of Youth Board deck shows three different states to a rider for user convenience: remaining battery SOC, current driving speed, and braking amount. Indoor EMC test results between Youth Board and Youth Wearable Controller and outdoor Youth Board driving test results are analyzed. In particular, driving test results show the maximum current output is about 15% lowered compared to the other competitor electric skateboard and it lessens the power burden of the motor ESC. These results show Youth Board's usefulness as a personal mobility in the sense of small, light, and inexpensive aspects.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.231-236
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• 2020

In today's society, the majority of people use smartphones, and mobile ordering and payment systems for their convenience are gaining their attention. The mobile payment market is on the rise, with over 71% of the market that is already formed in China. Many mobile payment markets are growing in Korea, which is a system that is provided only in large franchises. In this paper, we propose a mobile ordering and payment system using short-range wireless communication technology that can be easily used not only in franchises but also in the small businesses, and for the convenience of users in modern society to make a system that enables ordering and payment through mobile to communicate between the devices developed by short range wireless communication technology, smartphone and the main server.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1941-1948
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• 2016

The incident during commuting to school happened frequently in these days, such that the government announced the student commuting safety policy for addressing to implement the safety management system of the unsafer school commuting zone. In this paper, a commuting tracking system is proposed that notifies the location of vehicles and the boarding status of student using BLE beacon and smart phone GPS function. The commuting tracking system that gets the data from the system server of driver's smart phone GPS location and UUID of the beacon which had provided students has configured to provide notifications to parents and related administrators. It provides real-time information about whether a student boarding, boarding times and bus locations for parents and administrators. It verifies the disembarking time for each student and also provides to driver to secure if any student tries to board the wrong school bus and if any students is left behind in the bus.