• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.27-34
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• 2013

Most of existing biomedical signal measurement devices measure and evaluate biomedical signal only in a single device. Also, even if the device is multi-functional, those biomedical signals can be measured by selection of the user. In this paper, we implemented wristband-style biomedical signal measurement device for u-healthcare system to solve the problem above. Implemented device uses 4 infrared sensors to measure the pulse, 2 electrodes to measure the skin conductivity, and 3-axis accelerometer to measure momentum. Also, we propose a communication packet frame for transmitting biomedical signal data to PC or mobile device, using Zigbee. Studies show that our device has the error rate of less than twice for pulse measurement, 85.6%, 84.7% reliability for momentum measurement, and the skin conductivity has changed according to the user's physical status.

• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.99-114
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• 2007

The web-based discussion allows learners to participate in the learning actively and positively, and it can provide learners with the learner-oriented active interaction and learning environment. However, the web-based discussion produced communication-oriented learning environment using bulletin board and data directory and researched mainly the state and activation of the discussion, and had less system supporting dynamic discussion process. Even if the discussion made appearance partially and totally as learners' activities at a variety of web-based teaching, specific discussion-based teaching model was not developed. Therefore, a systematic web-based discussion system needs to be developed to activate human interaction and to give shape to the stages and elements of the discussion model. The paper supports dynamic discussion activities and applies Hill's common discussion model describing detailed discussion stages to develop systematic web-based discussion system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1189-1194
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• 2016

While increasing the convenience of life is a high population BMI (Body Mass Index) is increasing rapidly. Accordingly, the development of the monitoring system to manage and prevent obesity is the time that is required. But most of the monitoring system, the less information it receives management and show to have only simple information calculated this was a low efficiency problem. Also Users with normal and disease Management accuracy is low. In this paper shows the user in a graph of Body Mass Index, BMR (Basal metabolic rate) divided by grade increased accuracy for users to manage their own. Also represented by recovery with exercise machines you used, select a balanced movement mechanism, expressed as a Kcal consumption. If the graph recent data show only increased the visibility. We developed an efficient web-based monitoring system for design a exercise plan.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.721-728
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• 2009

Equal/unequal 4-way power divider suitable for satellite communication using SIW technology is presented in this paper. The control of positions of guiding posts provides equal or unequal power division ratios by maintaining the width of the SIW unchanged. In addition, the detailed descriptions for the proposed power divider include the general characteristics of radial waveguide, feeding part using coaxial cable, simple SIW structure, power-guiding posts, and transition for measurement. The comparison between the simulated and measured data shows a good agreement at a center frequency of 10 GHz. The measured input impedance bandwidths for equal and unequal power divisions are about 2.1 GHz and 3 GHz under the condition of less than VSWR 2:1, respectively.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.934-941
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• 2014

In this paper, we present a low profile 2-layered meander built-in monopole antenna for portable RFID reader using FDTD(Finite Difference Time Domain) method. The input impedance, return loss, and VSWR in the frequency domain are calculated by Fourier transforming the time domain results. The double meander 2-layer structure is used to enhance the impedance matching and increase the antenna gain. The measured bandwidth of the antenna is 0.895 GHz ~ 0.930 GHz for a S11 of less than -10dB. The measured peak gain of proposed low profile RFID built-in antenna is 2.3 dBi. And the proposed built-in antenna for portable RFID reader can offers relatively wide-bandwidth and high-gain characteristics, in respectively. Experimental data for the return loss and the gain of the antenna are also presented, and they are relatively in good agreement with the FDTD results. This antenna can be also applied to mobile communication field, energy fields, RFID, and home-network operations, broadcasting, and other low profile mobile systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.917-922
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• 2016

Recently, energy harvesting, in which energy is collected from RF signals, has been regarded as a promising technology to improve the lifetime of sensors by alleviating the lack of power supply problem. In this paper, we try to propose an efficient algorithm for simultaneous wireless information and power transfer. At first, we find the lower bound of water-level using the probability density function of channel, and derive the solution of power allocation in energy harvesting networks. In addition, we derive an efficient power splitting method for satisfying the minimum required harvested energy constraint. The simulation results confirm that the proposed scheme improves the average data rate while guaranteeing the minimum required harvested energy constraint, compared with the conventional scheme. In addition, the proposed algorithm can reduce the computational complexity remarkably with insignificant performance degradation less than 10%, compared to the optimal solution.

• Journal of Distribution Science
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• v.15 no.7
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• pp.73-83
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• 2017

Purpose - The purpose of this paper is to explore the CSR activities of small enterprises in hospitality and tourism industry in South Korea. Since previous research on CSR activities has considerably focused on large enterprises whereas small enterprises have relatively less attention, this study aims to explore the characteristics of small enterprises in hospitality and tourism industry and their CSR activities. Research design, data, and methodology - The population of interest for this study was social enterprises registered in Korea Social Enterprise Promotion Agency (2016), and it was used to verify the social enterprises which has a certification for social enterprises. From 1672 companies in total, the sampling frame was a database with 117 companies in hospitality and tourism industry. This study investigates social enterprises' CSR activities on the company's official websites (e.g., company reports, magazines, the news articles, and interviews). The websites of the selected enterprises in hospitality and tourism industry were analyzed for examining CSR activities by the quantitative content analysis. All of the CSR activities in small social enterprises were classified into six dimensions based on the stakeholder theory. Results - The findings of this study provide the characteristics of the 117 small social enterprises and their specific CSR initiatives. A total of eight main business lines were identified: 1) fair travel, 2) leisure/sports, 3) accommodation/camping, 4) medical tourism, 5) exhibitions/art events/cultural events, 6) leisure activities for vulnerable social groups, 7) Korean traditional culture, and 8) ecotourism/agricultural tourism. The CSR initiatives were classified into six dimensions: 1) environment, 2) employment, 3) multicultural families and vulnerable social groups, 4) local community, 5) economic prosperity, and 6) product. Conclusions - This study revealed the special CSR initiative examples of small enterprises in hospitality and tourism industry. Small social enterprises participate in CSR activities mainly related to their own business lines. Moreover, these enterprises are more closely embedded in their local community development, job creation and education for local residents and vulnerable social groups, and traditional heritage preservation. The findings of this study provide theoretical and practical implications and they can contribute to enrich CSR with literature for small enterprises in hospitality and tourism industry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.530-536
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• 2017

The accident of the small vessel is increasing due to the growth of the sea and service industry. According to data from National Statistical Office, for 100 ton less than small ship accident, the most of the shipping incident generated in the small ship by 84% of the total shipping incident in 2015. The radar obligatory mounting is enforced to the small vessel in order to conclude this problem. However, the problems including the maintenance cost and transmission power etc. happens high if the existing pulse radar is mounted in the small vessel. In this development, the development is for small ship fixed type radar the object. And in this paper, by using the phase array antenna revolving electronically around the beam, the antenna which it is applicable to the marine fixed type radar which can solve above problem was made and it tested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.189-196
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• 2012

A WAVE(Wireless Access for Vehicular Environment) system is a vehicle communication technology. The system provides the services to prevent vehicle accidents that might occur during driving. Also, it is used to provide various services such as monitoring vehicle management and system failure. However, the scrambler bit operation of WAVE system becomes less efficient in the organizations of software and hardware design because the parallel processing is impossible. Although scrambler algorithm proposed in this paper has different processing speed depending on input data 8 bit, 16 bit, 32 bit, and 64 bit. it improves the processing speed of the operation because it can make parallel processing possible depending on the input unit.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2195-2196
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• 2006

This study is for implementation of PC based Motor fault diagnosis system. By using harmonics and current signals of the motor, this system diagnoses the motor condition by accumulated harmonic contribution rate. In this proposed system that was composed of 5 parts. A sensor, connection box, evaluation board, device server, and main computer are those. There were two types of sensor, one was harmonic sensor the other was current sensors. The signal was acquired by sensor, and transferred to evaluation board. Second one is connection box. Because the output type of sensor and input type of evaluation board is different, connection box was necessary. Third one was evaluation board. The signal from the sensor was converted to digital signal in evaluation board. And this signal was transferred to device server. Fourth one was device server. Device server transferred the data from evaluation board to main computer. And the last one was other parts controlled by main computer. In main computer, there were communication and diagnosis algorithms. The result was derived by main computer. In the result, there were 12 categories and 5 levels of motor conditions. The proposed system had some advantages comparing with stand alone type commercial motor fault diagnosis system. The first, by using remote access it was easier to get the conditions of motor. The second, there was no need to handle the sensors when users measured the motor signals. By this property, no one was necessary at motor location site. The third, this system was less restricted by times and places than commercial stand alone type diagnosis system. Therefore users can operate this system only using the main computer. Once the sensors are installed at the motor, users doesn't need to move to check up the condition of motors. Moreover, if there is ethernet hub, many motors can be not only diagnosed at once but also decreased its cost.