• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.330-338
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• 2017

Purpose: The smartphone is actively being used in many research fields, primarily in medical and diagnostic applications. However, there are cases in which smartphone-based systems have been developed for agriculture, environment, and food applications. The purpose of this review is to summarize the research cases using smartphone cameras in agriculture, environment, and food. Methods: This review introduces seventeen research cases which used smartphone cameras in agriculture, food, water, and soil applications. These were classified as systems involving "smartphone-camera-alone" and "smartphone camera with optical accessories". Results: Detecting food-borne pathogens, analyzing the quality of foods, monitoring water quality and safety, gathering information regarding plant growth or damage, identifying weeds, and measuring soil loss after rain were presented for the smartphone-camera-alone system. Measuring food and water quality and safety, phenotyping seeds, and soil classifications were presented for the smartphone camera with optical accessories. Conclusions: Smartphone cameras were applied in various areas for several purposes. The use of smartphone cameras has advantages regarding high-resolution imaging, manual or auto exposure and focus control, ease of use, portability, image storage, and most importantly, programmability. The studies discussed were achieved by sensitivity improvements of CCDs (charge-coupled devices) and CMOS (complementary metal-oxide-semiconductor) on smartphone cameras and improved computing power of the smartphone, respectively. A smartphone camera-based system can be used with ease, low cost, in near-real-time, and on-site. This review article presents the applications and potential of the smartphone and the smartphone camera used for various purposes in agriculture, environment, and food.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.131-138
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• 2017

Lately, Internet-based vessels have begun to appear at sea with the development of ICT. Thereby crews have gained easy Internet access through increased smartphone portability. However, the side effects of smartphone use while on watch, have not been studied seriously despite being a reality. In this study, simulation experiments were carried out using a Ship Handling Simulator in order to distinguish the risks of using a smartphone while on watch. Proximity Evaluation, Control Evaluation, Subjective Evaluation and Situation Awareness to the dangerous situation were used to quantify risk during simulation, and analysis results were compared with cases when using and not using a smartphone. It was found that the degree of risk increased between 1.3 to 3 times given smartphone use. Consequently, this paper represents foundation for the restriction of smartphone use and proposes smartphone usage guideline for ship navigation.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.773-782
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• 2022

Estimation of cable tension through proper measurements is one of the essential tasks in evaluating the safety of cable structures. In this paper, a study on cable tension estimation using the built-in accelerometer and camera in a smartphone was conducted. For the experimental study, visual displacement measurement using a smartphone camera and acceleration measurement using a built-in accelerometer were performed in the cable-stayed bridge model. The estimated natural frequencies and transformed tensions from these measurements were compared with the theoretical values and results from the normal visual displacement method. Through comparison, it can be seen that the error between the method using the smartphone and the normal visual displacement is sufficiently small to be acceptable. It has also been shown that those errors are much smaller than the difference between the values calculated by the theoretical model. These results show that the deviation according to the type of measurement method is not large and it is rather important to use an appropriate mathematical model. In conclusion, in the case of cable tension estimation, it can be said that the visual displacement measurement and acceleration using a smartphone can be a sufficiently applicable method, just like the normal visual displacement method. It is also noteworthy that the smartphone accelerometer has a larger magnitude error and has more limitations such as high-frequency sampling instability compared to the visual displacement method, but shows almost the same performance as the visual displacement method in this cable tension estimation.

• Korean journal of communication and information
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• v.61
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• pp.52-73
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• 2013

The purpose of this study is to investigate the effect of motivations for using smatphones and tablet PCs on using applications. For this purpose, this study took a survey targeted for smartphone and tablet PC users. The results suggested that the motivations were consisted of four dimensions ; informations, communication, specific functions and relaxation. In terms of motivations, smartphone users preferred to use specific functions and tablet PC users preferred to use them for relaxation. The motivations for using applications were depended on types of applications. Smartphone users preferred communication applications to information or entertainment ones but tablet PC users preferred entertainment and information applications to communication ones. The results also suggested that motivations for using smartphone and tablet PC had strong impact on using applications in part. The motivations for using smartphone and tablet PC worked as a strong factor for using applications. Especially, the motivations of using smartphone had a strong positive relationship with using applications.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.25 no.2
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• pp.197-208
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• 2018

Purpose: This study investigated the smartphone using time, troubles with smartphone usage, and related factors in Korean adolescent smartphone users. Methods: Data were obtained from 54,603 subjects aged 13 to 18 years in the 2017 13th Korea Youth Risk Behavior Web-based Survey Results: The study analyzed the school type, academic achievement, residence type, weekly average allowance, and usual counselor, perceived stress, happiness, and depression of the subjects showed a significant difference in the variable of troubles experienced by the smartphone user. Multiple sample logistic regression analysis showed that adolescents with low academic achievement (weekday, weekend OR = 1.78, 1.65), low economic status (weekday, weekend OR = 1.17, 1.37), friends with distress counselors (weekday, weekend OR = 1.29, 1.24), weekly average allowance (weekday, weekend OR = 1.85, 1.50), stressed (weekend OR = 1.25), depressed (weekday, weekend OR = 1.26, 1.14), family troubles (weekday, weekend OR = 1.14, 1.15), friendship troubles (weekday, weekend OR = 1.70, 1.38), and academic performance troubles (weekday, weekend OR = 1.28, 1.38) spent more than the average using time on their smartphones. Conclusion: To prevent overdependence on smartphone use among adolescents, a nursing intervention program that relieves stress and lowers depression should be developed.

• Journal of Korea Game Society
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• v.20 no.1
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• pp.23-32
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• 2020

This study was attempted to investigate the factors that influence on problematic smartphone use and life satisfaction by smartphone usage type. A total of 25,465 people were used for the analysis and analyzed using the R (3.6.1) program. According to the data analysis, problematic smartphone use occurred in the form of leisure activity seeking and information seeking type. On the other hand, the communication type reduced problematic smartphone use. The type of smartphone use that had the greatest influence on life satisfaction was communication type The longer the smartphone use time and the higher the problematic smartphone use, the more negatively the life satisfaction.

• Asia pacific journal of information systems
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• v.27 no.4
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• pp.191-215
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• 2017

This study investigated the antecedents and the performance impact of two types of Smartphone functions (communication vs. computing functions) in organizational environment and the moderating impact of Smartphone users' organizational roles. More specifically, identifying two distinct types of Smartphone functions such as communication functions and computing functions (including informational, social network, and resource management functions), we investigated the impact of three antecedents (Smartphone dependency, task mobility, and perceived critical mass) on the use of the two Smartphone functions and how organizational workers' perceived performance gains differ by using these two different Smartphone functions for their workplace activities. We tested our hypotheses with survey data collected from 176 organizational workers. Our findings suggest that Smartphone dependency, task mobility and perceived critical mass of Smartphone use are significantly associated with the use of the two different functions, and that the use of computing functions is more strongly associated with perceived performance gain than the use of communication functions. We also found that managerial roles played by individual workers differently moderate the impact of Smartphone use on perceived performance gain. The present findings enable researchers and practitioners to better understand the impact of Smartphone use in workplaces.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.93-103
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• 2019

This study analyzed the impact of smartphone usage on walking speed during walking on two pedestrian walkways in Daejeon Metropolitan City. For the analysis, the video data about the actual use of smartphone was acquired and the walking speed was calculated based on the walking density of the pedestrian Level Of Service(LOS) presented in the Road Capacity Manual. Multiple regression analysis and decision tree using machine learning were used to analyze the impact of smartphone usage on walking speed, and as the explanatory variables, gender, disable smartphone, use of smartphone using auditory function, use of smartphone using visual function, LOS A, LOS B, LOS C were adopted. The result showed that LOS C had the highest impact on walking speed change and the women's group using their visual function was founded to have the slowest walking speed in LOS C. In particular, the author found that walking speed significantly decreased in the case of use of visual function rather than listening to music or the hearing on the phone.

• Human Ecology Research
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• v.59 no.4
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• pp.557-567
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• 2021

This study examined the relationship between COVID-19 stress, self-regulation, and smartphone addiction among university students. It also assessed whether self-regulation mediates the relationship between COVID-19 stress and smartphone addiction. The participants comprised 346 students enrolled in G city university. Data were analyzed using SPSS and AMOS to generate descriptive statistics, perform a correlation analysis, and create a structural equation model. The main findings were as follows. First, COVID-19 stress had a negative correlation with self-regulation, but a positive correlation with smartphone addiction. A negative correlation was observed between self-regulation ability and smartphone addiction. Secondly, self-regulation partially mediated the relationship between COVID-19 stress and smartphone addiction. The results will inform educational and counseling interventions aimed at preventing smartphone addiction among university students living in the era of the COVID-19 pandemic.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.71-76
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• 2019

Research on indoor location tracking technology using smartphone is actively being carried out. Especially, the movement distance of the smartphone should be accurately measured and the movement route of the user should be displayed on the map. Location tracking technology using sensors mounted on smart phones has been used for a long time, but accuracy is not good enough to measure the moving distance of the user using only the sensor. Therefore, when the user moves the smartphone in a certain posture, it must research and develop an appropriate algorithm to measure the distance accurately. In this paper, we propose a method to reduce moving distance estimation error by removing user 's foot shape by limiting the screen of smartphone in pyramid - based optical flow estimation method.