• Journal of Sensor Science and Technology
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• v.22 no.1
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• pp.54-64
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• 2013

In this study, we developed a falling recognition system to transmit SMS data through CDMA communication using a three axises acceleration sensor and a two axises gyro sensor. 5 healthy men were selected into a control group, and the fall recognition system using the three axises acceleration sensor and the two axises gyro sensor was devised to conduct an experiment. The system was attached to the upper of their sternum. According to the experiment protocol, the experiment was carried out 3 times repeatedly divided into 3 specific protocols: falling during gait, falling in stopped state, and falling in everyday life. Data obtained in the falling recognition system and LabVIEW 8.5 were used to decide if falling corresponds to that regulated in an analysis program applying an algorithm proposed in this study. In addition, results from falling recognition were transmitted to designated cellular phone in a SMS (Shot Message Service) form. These research results show that an erroneous detection rate of falling reached 19% in applying an acceleration signal only; 6% in applying an angular velocity; and 2% in applying a proposed algorithm. Such finding suggests that an erroneous detection rate of falling is improved when the proposed algorithm is applied incorporated with acceleration and angular velocity. In this study therefore, we proposed that a falling recognition system implemented in this study can make a contribution to the recognition of falling of the aged or the disabled.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.11
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• pp.247-249
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• 2020

In the era of the 4th industrial revolution, the demand for convergence between ICT technologies is increasing in various fields. Accordingly, a new term that combines data, network, and artificial intelligence technology, DNA (Data, Network, AI) is in use. and has recently become a hot topic. DNA has various potential technology to be able to develop intelligent application in the real world. Therefore, this paper introduces the reviewed papers on the service image placement mechanism based on the logical fog network, the mobility support scheme based on machine learning for Industrial wireless sensor network, the prediction of the following BCI performance by means of spectral EEG characteristics, the warning classification method based on artificial neural network using topics of source code and natural language processing model for data visualization interaction with chatbot, related on DNA technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.489-498
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• 2003

Recently to introduce new services of ultra-high speed wireless access and systems beyond the 3rd generation mobile communication, 5 GHz band has been highly interested. As a way of getting the required frequency, it is considered that microwave relay bands below 6 GHz, which shows a slow decrease in demand and less cost-effectiveness, should be moved to other bands above 6 GHz. In this paper, as a tool for analyzing microwave link design and its service quality, the outage prediction based upon Vigants & Barnett＇s model is reviewed. To show outage and availability calculation, simulations are performed for the operating 4 GHz radio sites, and some results and features regarding frequency movement to 6.7 as well as 8 GHz are also discussed in terms of diversity techniques, bit error rate, and availability As the results, it is confirmed that only the diversity techniques of space or space and frequency can satisfy the annual objective of availability irrespective of frequency movement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.753-762
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• 2013

This paper forecast that, if the EMC test market for broadcasting and communication materials and equipment reaches a saturated state, such will give rise to adverse effects such as capture phenomenon, rent seeking phenomenon, and stiff test price competition; this in turn will eventually wield a negative impact on our society. Thus, to determine the saturation level of EMC test markets, the size of test markets and test capabilities of the designated laboratories were surveyed. As a result, the operation rate of equipment in the EMC test markets was revealed to be 78 %, suggesting market saturation. Moreover, the wireless, wire, and SAR equipment operation rates reached 65 %, 3 %, and 10 %, respectively, suggesting market saturation. Thus, maintaining the strictness of testing requires limiting the designation of new test laboratories; in light of practices and implementation of laws, however, the relevant administrative agency has difficulty rejecting applications for the designation of laboratories.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.11-19
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• 2015

Due to recent development in mobile devices, the mobile device utilization and many related applications have been increasing. Most of initial applications on mobile devices just showed simple information, but now they processes huge data. However, smart devices have certain limitations in processing massive data. Especially, if the size of data increases, the speed of data processing adversely decreases, so the performance of programs also decreases. If hardware specification of the mobile devices is not enough to handle it, response time will be drastically delayed. To overcome these drawbacks, most of application running on mobile devices communicate with their servers to manage data. XML is a proper language for data communication to send and receive data between servers and mobile devices, because it defines rules of document's format and it is a textual data format and small-sized language. However, mobile devices have limitation such as memory, CPU and wireless network to process huge data and XML also takes a lot of time to communicate with servers and devices and handle data, so it could be overhead in service time. Binary XML is an alternative of performance improvement in data processing, which has XML's benefits and minimizes the XML size by binary coding. However, most of binaryXML which are used on applications don't fit on mobile applications. In this paper, we surveyed many kinds of binaryXML, compared merits and demerits to find a binaryXML for mobile applications. We propose how to use binary XML and implemented an electronic attendance system using binary XML to overcome the limitation of XML and to reduce the load of data communications between servers and devices.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.483-489
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• 2006

In this paper, new wideband lens amplifiers are proposed for C-band wireless communication service. In order to obtain the wideband property, all components of the proposed lens amplifiers are designed with balanced structure and wideband characteristics. Fat dipole antenna as the input and output antenna, balanced amplifier as amplifying components, and coplanar stripline(CPS) as the delay line fer the beam focusing are used fur composing the stable wideband lens amplifier. The $5{\times}5$ 2D lens amplifier has the characteristics that the absolute gain is 7.5 dB, the EIPG is 37.4 dB at 6 GHz, and the 3-dB gain bandwidth is 19.8 %.

• Spatial Information Research
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• v.18 no.3
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• pp.53-62
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• 2010

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.677-685
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• 2012

Recently, wireless multi-networking technology has been studied for supporting multi-interface in mobile node. As the related work, in the IETF NetExt WG, the extension of Proxy Mobile IPv6 protocol for supporting flow mobility is actively on going in discussion. PMIPv6 protocol supports simultaneous access through the multi-interface in a mobile node and inter-technology handover between multiple interfaces. However, this protocol can not support flow mobility. Thus, in this paper, when a mobile node connects to PMIPv6 domain through multi-interface, as a way to support flow mobility, the design of logical interface and Home Network Prefix change scheme based on logical interface are proposed, We show that the proposed scheme can perform flow mobility service without end-to-end disconnection in PMIPv6 domain.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.163-170
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• 2007

The next generation communication environment consists of various wireless access networks with distinct features that are configured as an overlay topology. In the network environments, the frequency of hand overs should be minimized and the error propagation should be solved in order to provide high-quality multimedia services to mobile users. Therefore, we propose an performance enhancement approach, based on mSCTP, that provides high quality multimedia services to mobile users by ameliorating the error propagation problem. We utilizes the following four functions: 1) the separation of transmission paths according to the types of frames. 2) retransmission strategy to minimize the loss rate of frames, 3) Foced vertical handover execution by utilizing bicasting, 4) using the stability period in order to reduce the effect of the ping pong phenomenon. The simulation results show that the proposed approach provides seamless multimedia service to mobile users by achieving error resilience.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.88-97
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• 2010

Recently the more convenient services are provided to people in the city in line with the change of city paradigm and the recent development of ubiquitous. For example, Information on bus arrivals an effective advertisement the combination of high technology and departures through smart-phones. However, in respect of the mobile advertisement, because of difficulties such as the means of transferring the mass storage data or the burden of communication charges. there need means to improve such difficulties. This study has been conducted aiming to overcome such difficulties. This study suggests the strategic differentiation plan through the analysis of the media characteristics such as real time service information when in traveling, U-Bus business model in the category of mobile advertisement, etc. and also the concrete system establishment plan from the operation center via network to the delivery of the advertisement through vehicle terminals. In respect that this study suggests the implications as a practical business model through the fusion of high technology and diverse media. It has great significance.