• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.4
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• pp.434-443
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• 2012

Purpose: This study was conducted to investigate sleep patterns in nursing students as measured by an automated wireless sleep tracker and self-reported sleep scales. Methods: Data were collected from October, 2011 to May, 2012. ZQ (a symbolic number that measures the quality and quantity of sleep) was calculated from the automated wireless sleep tracker. Pittsburgh Sleep Quality Index-Korean version, Sleep scale A, and sleep satisfaction were used as self-report sleep scales. Female nursing college students (n=37) were recruited by convenience sampling. Before going to bed, they were asked to put on a head-band type sleeping sensor and to move it the next morning. Every student slept 2~4 nights with the sleep tracker. Data were collected for 86 (91.4%) of 94 nights' sleep. The students were also requested to fill in the PSQI-K, sleep scale A, and sleep satisfaction. Results: The only statistically significant correlation was between ZQ and sleep satisfaction (r=.869, p=.026). The biggest obstacle in using this device was putting on the head-band type sensor. Conclusion: Validity of the wireless sleep tracker was verified in part. The usefulness of this device in nursing research and practice was identified. Further evaluation need to be conducted with various populations.

• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.218-225
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• 2020

Purpose Wearable devices are widely used in our daily life. The purpose of this study is to investigate the relationship between persuasive designs of fitness trackers and users' physical activity behavior. Methods To test the research model, data was collected from a web-based survey in China, resulting in an effective sample of 166 usable questionnaires. The survey was restricted only to respondents who wear a fitness tracker. Results The sample surveyed in this study indicated that half of the respondents had been wearing a smart fitness tracker shorter than one year, and only 27% were long-time users (longer than two years). Dialogue support and social support strategies were both proved to be effective in increasing users' workout behavior intention. Social support strategies had a greater effect on behavior change than dialogue support strategies. Conclusion The findings from this study make several contributions to the practice. Wearable devices developers can employ the result from this study to help them design devices, which can persuade people to do more exercises and preserve a healthier life.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.143-146
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• 2006

본 연구는 개인용 PC 에 장착할 수 있는 저가의 가상현실게임 엔진을 설계하고 구현한다. 가상현실 엔진구현에서는 주요한 입출력 장치인 Tracker 와 HMD(Head Mounted Display) 그리고 조이스틱과 마우스의 장착이 필수적이다. 가상현실 엔진을 연동하기 위한 입출력 클래스를 설계하고 입력장치로 마우스와 조이스틱, 출력장치로 HMD 를 장착하였으며 Tracker 의 구현은 상업용 제품인 Polhemus의 Patriot tracker를 이용하였다.

• Journal of the Speleological Society of Korea
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• no.89
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• pp.27-33
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• 2008

Solar energy is most green and clean, unlimited and sustainable energy source on the earth. It is almost 97% of imported consumer energy in Korea. Because of resource poor nation, it is necessary to do their best to make alternative energy to allot their deficiency of the matter in hand of energy resources of petroleum. In a point of view of this problems, the natural solar energy should be improved by any methods as much, possible as we need. Photovoltaic generation with solar tracking system for obtaining optimal power is one of most benefit equipment to improve power of solar-cell panel producing clean electric power efficiently. Solar tracker is a device for orienting a solar photovoltaic panel toward the sun perpendicularly to sunlight, especially in widely separated place. For this reason, we are very interested in developing the equipment system of tracker, specially in solar cell applications, obtaining a high degree of accuracy to ensure that the optimal sunlight could be directed precisely against to the powered device. As a result, it was obtained of 12.46 volts at 90$^\circ$toward solar panel and 9.44 volts at 45$^\circ$, furthermore, improved efficiency more than 30% of average output voltage between tracker system (12.41V) and fixed system (8.55V), respectively. It is also very useful for optimum power system of widely separated cave.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2470-2476
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• 1997

We propose a simle scheme for detecting tone signals narrowly spaced in the frequency by employing a nonlinear device called Teager's energy tracker. When the input signal is a tone signal, the output of Teager's energy tracker is proportional to the energy and tone frequency of the input signal. When the envelope of the input tone is varying, this tracker can also track the energy of the envelope. By employing Teager's algorithm as a preprocessor, the detector for narrowly spaced tone signals can be implemented without the use of sharp notch filters. As an example, the proposed detector is applied to distinguishing ITU-T V.8 and V.25 tone signals. The detector perfodrmance is analyszed and is verified by computer simulation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.4
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• pp.26-31
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as solar energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. The solar tracker consists of sun point detector module, mechanical mechanism module with actuator and control system module. This paper presents sun point detector for solar tracker of daylight system. To evaluate the detecting accuracy, an experimental device is implemented. In experimental results, the accuracy of development system has under 0.11%/0.5deg.

• Fashion & Textile Research Journal
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• v.23 no.3
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• pp.390-405
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• 2021

Gait analysis trackers have been developed to monitor daily gait patterns to improve users' running performance and reduce the risk of injuries. A variety of gait analysis trackers are available on the market(e.g., foot pods, insoles). Depending on the type of gait analysis tracker, users' discomfort or satisfaction as well as required properties may differ. Hence, the purpose of this study was to compare and analyze user experience of three different types of commercial shoe-mounted gait analysis trackers and their mobile applications in a laboratory environment using questionnaires based on actual experiences of each product. Ten males and ten females who regularly enjoy walking and running exercises participated in the experiment. After the participants set up the tracker and application themselves without support from researchers, ten to thirty minutes' exercise was permitted on each product. Following this, the participants answered questionnaires containing evaluation variables on the device and mobile application, as well as satisfaction, intention to use, recommendation, and purchase. In addition, they were asked questions about the attractive features and shortcomings of each device and application. The results showed that the PRO-SPECS^® smart insole was preferred over the others for ease of use, perceived durability, psychological burden of the design, and usefulness of the information provided by the application. Along with the results of questionnaire, this study also discussed strategies and recommendations for future product design and development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.49-58
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• 2019

The Scientific balloon is a flight system that could recover an entire platform at the end of the mission. The recovery takes place mainly in low-density populated areas, taking into account for the possible damage to the human life and public safety. In Republic of Korea, on the other hand, marine recovery should be considered due to the dense mountainous terrain and restrictions of the peninsula. In this operating environment, the envelope must be recovered because of severe marine pollution that may occur after the splashdown. Therefore, in this study, the separation device that consists of a location tracker and the waterproof system were developed. The device includes data transmission/reception, separation, and waterproof systems which are manufactured considering the environmental condition of the Korea. The performance of the device and the trajectory of the envelope were verified by conducting a separation test of a 20km platform at a target altitude and the recovery of the zero-pressure balloon.

• Convergence Security Journal
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• v.16 no.4
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• pp.63-68
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• 2016

This study examined the current state of fitness IT which are commercially available, and proposed the prospect and promoting plans for fitness IT. Latest wearable smart market has been reorganized into smart watch market and fitness tracker market. Fitness trackers which are typical devices of fitness IT technology has developed various types of such as watch, band, clothes, glasses, and lens. Until now, the most popular type of fitness tracker are watch and band including clip, necklace, hair band etc.. Also Apple and Google referred to as the two major axes of mobile platform has provided a health-related platform such as "Healthkit" and "Google Fit" for preoccupying the fitness business. The view of the fitness IT has seen a continuous growth trend considering smaller and lighter of fitness-related wearable device. To continuous growth and promote of fitness IT, it is expected to require mash-up a variety of fitness applications and services, ensuring the convenience of user experience, design and resonable price.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.10-18
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• 2016

The cognitive ability of humans depends much on the vision. 'Vision' refers to the sense that receives stimulus of light through eyes. 'Gaze' refers to a function of a straight line that connects the central point of the pupil and a viewpoint in the external world, and, in general, it means a straight line that connects an object that is viewed and the eyes. There are active studies on the gaze in various academic circles including 'psychology' and 'cognitive linguistics.' As a method to objectively analyze the gaze, studies on 'eye tracking' are revitalized. A device for studies on eye tracking is an 'eye tracker.' As the fields of the study expand from development and analysis of Web pages to analysis of stores, methods of traffic signal processing, transport equipment, analysis of user experiences on image contents, and marketing analysis, there occurs a greater demand for a glasses eye-tracking than that for a fixed eye tracker. This study identifies the overview and characteristics of eye tracking and presents a way for spreading studies on eye tracking.