• Journal of Digital Contents Society
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• v.18 no.3
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• pp.559-565
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• 2017

A lot of studies have been conducted to recognize the motion state or behavior of the user using the acceleration sensor built in the smartphone. In this paper, we applied the neural networks to the 3-axis acceleration information of smartphone to study human behavior. There are performance issues in applying time series data to neural networks. We proposed a multi-temporal neural networks which have trained three neural networks with different time windows for feature extraction and uses the output of these neural networks as input to the new neural network. The proposed method showed better performance than other methods like SVM, AdaBoot and IBk classifier for real acceleration data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2213-2221
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• 2015

The ondemand governor used in android-based smartphone platforms is a CPU frequency scaling technique. The ondemand governor sets the CPU operating frequency depending on the CPU utilization rate. Job scheduling affects the CPU utilization rate. The power consumption is proportional to the value of operating frequency. Consequently, CPU frequency scaling and CPU utilization rate have an effect on power consumption in a smartphone. In this paper, we evaluated the performance of job scheduling techniques incorporating the ondemand governor in terms of CPU utilization, power consumption, and job deadline miss ratio.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.119-125
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• 2018

Various techniques for indoor positioning using a smart phone have been studied. Among them, the positioning technology using the acceleration sensor and the gyro sensor built in the smartphone is widely used in conjunction with the WiFi fingerprint technology. The location tracking technology using sensors has been used for a long time, but the performance environment of the smartphone is poor and the user is moving with the smartphone in a certain posture. Therefore, in order to improve the accuracy of location tracking in a smartphone environment, it is necessary to study and develop appropriate algorithms in a mobile environment. In this paper, we analyze the performances of frequency analysis method, maximum sum of minimum acceleration method and adaptive threshold method, which are the user's moving step count detection algorithms, and determine the most accurate method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.429-437
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• 2015

The purpose of this study was to investigate physical activity level, sleep quality, attention control, and self-regulated learning along to smartphone addiction level among college students. The data were obtained from 269 college students by structured questionnaire, analyzed using SPSS 18.0. The results showed that significant differences with smartphone addictoin level and, gender, grade level, daily using time, physical activity level, sleep quality and attention control. Smartphone addictoin level have correlations with physical activity level, sleep quality, attention control, and self-regulated learning. To prevent the falling off of physical strength and poor school performance, it is needed a strategies for control of smartphone addiction.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1543-1550
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• 2017

Previous research on smartphone has been focused on personal performance, accessibility, and information gaps in information system quality. In order to analyze the relationship between the use of smartphone information and personal characteristics, this study conducted a survey of 300 tourists at Jeju Airport, by using three variables of self-efficacy, 'impulsiveness and demographic variables (age, sex, education level, etc.) of smartphone use with personal characteristics. In conclusion, self-efficacy and impulsiveness seem to be positively related to the use of smartphone because it seems to be a living environment in which the desired information can be acquired within a desired time. In addition, there seems to be a difference between a mobile native environment in which online and offline boundaries are always connected and an environment in which 40 to 50 digital literacies are connected. This can be interpreted as a result of additional analysis.

• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.84-92
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• 2021

This study was conducted to identify factors related to the problematic experiences of smartphone use among adolescents according to gender. The subjects of this study were 54,603 male and female adolescents. This study data was analyzed using SPSS 25.0 program. As a result of this study, the relevant factors for the problematic experiences of smartphone use among male students were academic performance, economic level, counselors, fast food consumption frequency, depression, suicidal ideation, suicide plan, happiness, subjective body image, stress, and smartphone usage time. Drinking and smoking were found to be significant related factors only for female students. Therefore, in order to reduce the problematic experience of smartphone use, an intervention considering the influence factors according to gender is required.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.127-134
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• 2019

The purpose of this study was to investigate the factors affecting the behavior intention of smartphone mobile banking service among tourists. Currently, due to the development of mobile Internet technology and the spread of smartphone all over the world, interest and spread of smart phone based mobile banking is popularized. Thus, we analyzed the relationship among performance expectancy, social influence, facilitating conditions, perceived financial cost, perceived habit, perceived security level, and user's behavioral intention as a dependent variable. In this study, 203 respondents were interviewed about Chinese tourists at Jeju International Airport, and the influence of independent variables was determined by Smartpls 3.0. The results showed that the perceived security level and habit had a positive effect on the behavior intention. Especially, perceived security is a major issue of smartphone-based mobile banking in recent years. This study is meaningful in that it is an analysis of behavior factors of smartphone-based mobile banking service for tourists.

• ETRI Journal
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• v.37 no.1
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• pp.157-164
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• 2015

As GPU power consumption in smartphones increases with more advanced graphic performance, it becomes essential to estimate GPU power consumption accurately. The conventional GPU power model assumes, simply, that a GPU consumes constant power when turned on; however, this is no longer true for recent smartphone GPUs. In this paper, we propose an accurate GPU power model for smartphones, considering newly adopted dynamic voltage and frequency scaling. For the proposed GPU power model, our evaluation results show that the error rate for system power estimation is as low as 2.9%, on average, and 4.6% in the worst case.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.5
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• pp.352-359
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• 2016

The soft keyboard with touch interaction is universally available on mobile phone, a variety of previous studies with respect to the soft keyboard on smart devices had been conducted. However, previous studies of cursor control for text entry on smart devices such as smartphone did not performed. In this study, we compared three types of cursor controls (Default, 3D touch, Slide) in smartphone using Fitts' law and C-D ratio. Then we performed a laboratory experiment with three cursor control types and evaluated using cursor movement time as a quantitative evaluation and 8 subjective metrics for usability as a qualitative evaluation. Then, we discussed what types of cursor control showed better performance and subjective satisfaction through their results. From these results, this study recommended the design guidelines for cursor control on smartphones and developed its study methods as our contributions.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.353-358
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• 2013

In this paper, we present an implementation of indoor flight to navigate to the designated places capable of hands-off autonomous operation within indoor environments. Our flight requires computer vision technique and smartphone device to allow it to be flown indoors without high-performance sensors which are too expensive to commercialization. The experimental result show that proposed implementation is fairly meaningful in a general building.