• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1588-1595
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• 2021

Android-based smartphones receive the global navigation satellite system (GNSS) signals to determine their location and provide the GNSS raw measurement to users. The available GNSS signals on the current Android devices are GPS, GLONASS, Galileo, BeiDou, QZSS. This research has analyzed the performance of multi-GNSS position accuracy based on the pseudorange of the smartphone for maritime users. Smartphones capable of receiving dual-frequency are installed on a ship, and multi-GNSS raw information in maritime environment was measured to present the results of comparing the GNSS pseudorange-based dual-frequency positioning performance for each smarphone. Furthermore, we analyzed whether the results of the positioning performance can meet the HEA requirement of IMO for maritime navigation users. As the results of maritime experiment, it was confirmed that in the case of the smartphones supporting the dual-frequency, the position accuracy within 6 meters (95%) could be obtained, and the HEA position accuracy performance within 10 meters (95%) required by IMO could be achieved.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.49-55
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• 2015

According to the statistics of traffic accidents over recent 5 years, traffic accidents during the night times happened more than the day times. There are various causes to occur traffic accidents and the one of the major causes is inappropriate or missing street lights that make driver's sight confused and causes the traffic accidents. In this paper, with smartphones, we designed and implemented a lane luminance measurement application which stores the information of driver's location, driving, and lane luminance into database in real time to figure out the inappropriate street light facilities and the area that does not have any street lights. This application is implemented under Native C/C++ environment using android NDK and it improves the operation speed than code written in Java or other languages. To measure the luminance of road, the input image with RGB color space is converted to image with YCbCr color space and Y value returns the luminance of road. The application detects the road lane and calculates the road lane luminance into the database sever. Also this application receives the road video image using smart phone's camera and improves the computational cost by allocating the ROI(Region of interest) of input images. The ROI of image is converted to Grayscale image and then applied the canny edge detector to extract the outline of lanes. After that, we applied hough line transform method to achieve the candidated lane group. The both sides of lane is selected by lane detection algorithm that utilizes the gradient of candidated lanes. When the both lanes of road are detected, we set up a triangle area with a height 20 pixels down from intersection of lanes and the luminance of road is estimated from this triangle area. Y value is calculated from the extracted each R, G, B value of pixels in the triangle. The average Y value of pixels is ranged between from 0 to 100 value to inform a luminance of road and each pixel values are represented with color between black and green. We store car location using smartphone's GPS sensor into the database server after analyzing the road lane video image with luminance of road about 60 meters ahead by wireless communication every 10 minutes. We expect that those collected road luminance information can warn drivers about safe driving or effectively improve the renovation plans of road luminance management.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.452-459
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• 2022

One of the important factors among the smart farm factors is environmental measurement. This study tried to design an environmental measurement monitoring system through Bluetooth wireless communication with LoRa using the open source programs Arduino, App Inventor, and Node Red. This system consists of Arduino, LoRa shield, temperature and humidity sensor (SHT10), and carbon dioxide sensor (K30). The environmental measurement system is configured as a system that allows the sensor to collect environmental data and transmit it to the user through wireless communication to conveniently monitor the farm environment. As libraries used in the Arduino program, LoRa.h, Sensirion.h, LiquidCrystal_I2C.h and K30_I2C.h were used. When receiving environmental data from the sensor at regular intervals, coding using average value was used for data stabilization. An Android-based app was developed using Node Red and App Inventor program as the user interface. It can be seen that the environmental data for the sensor is well collected with the screen output to the serial screen of Arduino, the screen of the smartphone, and the user interface of Node Red. Through these open source-based platforms and programs will be applied to various agricultural applications.

• Physical Therapy Korea
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• v.20 no.2
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• pp.52-59
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• 2013

The purpose of this study was to determine the reliability and validity of the postural balance program which uses the movement accelerating field principles of posture balance training and evaluation equipment and smartphone movement accelerometer program (SMAP) in healthy young adults. A total of 34 people were appointed as the subject among the healthy young adults. By using Biodex stability system (BSS) and SMAP on the subject, the posture balance capability was evaluated. For the test-retest reliability, SMAP showed the intra-class correlation (ICC: .62~.91) and standard error measurement (SEM: .01~.08). BSS showed the moderate to high reliability of ICC (.88~.93) and SEM (.02~.20). In the reliability of inter-rater, ICC (.59~.73) as to SMAP, showed the reliability of moderate in eyes open stability all (EOSA), eyes open stability anterior posterior (EOSAP), eyes open stability medial lateral (EOSML) and eyes open dinamic all (EODA), eyes open danamic anterior posterior (EODAP), and eyes open danamic medial lateral (EODML). However, ICC showed reliability which was as low as .59 less than in other movements. In addition, BSS showed the reliability of high as ICC (.70~.75). It showed reliability which was as low as ICC (.59 less than) in other movements. In correlation to the balance by attitudes between SMAP and BSS, EOSML (r=.62), EODA (r=.75), EODML (r=.72), ECDAP (r=.64), and ECDML (r=.69) shown differ significantly (p<.05). However, the correlation noted in other movements did not differ significantly. Therefore, SMAP and BSS can be usefully used in the posture balance assessment of the static and dynamic condition with eyes opened and closed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5506-5511
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• 2012

u-Wellness is widely applicable to individuals and medical service providers such as hospitals and it includes u-fitness and video health counselling services at the side of the provider and stress management, obesity management, and the amount of exercise at the side of the individual. In this paper, we design and implement a smart health care system which uses the authentication device to identify an individual and the user's smart phone. Our system records and manages the amount of exercise on the basis of the prescription of health care professionals through the exercise equipment and Wi-Fi communication. Therefore, our system helps user do optimized amount of exercise through the health care professional's prescription. And our system quantifies the results of the measurement of body fat measuring machines and experts to build the database and automatically schedule.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.6
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• pp.369-378
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• 2019

Background: Behavior guidance is a technique used to subdue inappropriate behavior by establishing communication that meets the needs of a child. This study aimed to measure the effectiveness of a mobile app (Little Lovely Dentist) compared to the tell-show-do (TSD) technique in managing anxious children during their first dental visit. Methods: Fifty children (30 boys and 20 girls) without any past dental experience, aged from 7 to 11 years, were randomly allocated into either the dental app group or the TSD group. The pre- and post-operative anxiety of children who underwent prophylactic cleaning was assessed both physiologically and subjectively using a heart rate measurement and the RMS pictorial scale, respectively. Results: The intragroup comparison of heart rate and RMS scores for children allocated to the dental app group was statistically significant (P value ≤ 0.001). However, a significant reduction only occurred in the RMS scores, but not the heart rate measurements, in the TSD group. Conversely, there was an increase in heart rates in the TSD group. Conclusion: Educating the child prior to a dental procedure using a smartphone application such as Little Lovely Dentist can significantly alleviate the anticipatory anxiety and engage children in dental treatment during their first visit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.486-492
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• 2011

In this paper we analyzed performance of Andriod's Davik virtual machine(VM) using standard benchmark and compared the result with the embedded Java virtual machine. We used a well known benchmark suit named SPECJVM for the measurement. For the fair comparison, Sun Java embedded JVM is ported and the same benchmark is ported on it. The Odriod smartphone hardware platform is used as the target hardware. We have added a Just-In-Time compiler to Dalvik, which is not supported in the recent Android release, and measured performance improvement. The experiment result show that Dalvik achieved 15% and Dalvik with JIT shows 63% of the Sun's JVM performance.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.671-676
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• 2016

Recently, according to the limelight of Fintech, simple payment using biometric at smartphone is widely used. In this paper, we propose a new contactless biometric method using thumb image without additional sensors unlike previous biometrics such as fingerprint, iris, and vein recognition. In our method, length, width, and skin texture information are used as features. For that, illumination normalization, skin region segmentation, size normalization and alignment procedures are sequentially performed from the captured thumb image. Then, correlation coefficient is calculated for similarity measurement. To analyze recognition accuracy, genuine and imposter matchings are performed. At result, we confirmed the FAR of 1.68% at the FRR of 1.55%. In here, because the distribution of imposter matching is almost normal distribution, our method has the advantage of low FAR. That is, because 0% FAR can be achieved at the FRR of 15%, the proposed method is enough to 1:1 matching for payment verification.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.181-194
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• 2017

In recent years, research has been actively conducted on the navigation in an indoor environment where Global Navigation Satellite System signals are unavailable. Among them, a study performed indoor navigation by integrating pseudolite carrier and Inertial Measurement Unit (IMU) sensor. However, in this case, there was no solution for the cycle slip occurring in the carrier. In another study, cycle slip detection and compensation were performed by integrating Global Positioning System (GPS) and IMU in an outdoor environment. However, in an indoor environment, cycle slip occurs more easily and frequently, and thus the occurrence of half cycle slip also increases. Accordingly, cycle slip detection based on 1 cycle unit has limitations. Therefore, in the present study, the aforementioned problems were resolved by performing indoor navigation through the integration of pseudolite and ultra-low-cost IMU embedded in a smartphone and by performing half cycle slip detection and compensation based on this. In addition, it was verified through the actual implementation of real-time navigation.

• PNF and Movement
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• v.16 no.1
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• pp.133-141
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• 2018

Purpose: This study examined the effect of proprioceptive neuromuscular facilitation (PNF) rehabilitation exercise on postoperative range of motion (ROM), pain, and function of breast cancer patients. The purpose of this study was to provide fundamental data regarding the use of PNF rehabilitation exercise for patients with breast cancer. Methods: Fourteen patients who underwent surgery due to breast cancer were randomly divided into an experimental group (n=7) that performed PNF rehabilitation exercise and a control group (n=7) that performed general rehabilitation exercise. Both groups performed the respective exercises for 30 minutes, five times a week for 4 weeks. For the measurement of ROM, the range of shoulder abduction was measured using a clinometer smartphone application. The shoulder pain and disability index (SPADI) was used to measure the level of pain and functional activity. A paired t-test was conducted to compare within-group changes before and after the PNF rehabilitation exercise. Differences between the experimental group and control group were analyzed by an independent t-test. For all tests, the level of statistical significance was set at ${\alpha}=0.05$. Results: After the exercise, there was a significant within-group change in the ROM and SPADI in both the experimental group and control group (p<0.01). There was also a significant between-group difference in the ROM and SPADI after the intervention (p<0.05). Conclusion: Rehabilitation exercise is generally applied as a treatment for patients with breast cancer after surgery and is relatively effective. The application of PNF rehabilitation exercise may be useful in such patients, considering its effects on ROM improvement, pain reduction, and functional enhancement.