• Electronics and Telecommunications Trends
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• v.33 no.3
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• pp.89-99
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• 2018

Human activity recognition (HAR) is a technology that aims to offer an automatic recognition of what a person is doing with respect to their body motion and gestures. HAR is essential in many applications such as human-computer interaction, health care, rehabilitation engineering, video surveillance, and artificial intelligence. Smartphones are becoming the most popular platform for activity recognition owing to their convenience, portability, and ease of use. The noticeable change in smartphone-based activity recognition is the adoption of a deep learning algorithm leading to successful learning outcomes. In this article, we analyze the technology trend of activity recognition using smartphone sensors, challenging issues for future development, and a strategy change in terms of the generation of a activity recognition dataset.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.99-104
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• 2013

With diversity of mobile services (e.g., messenger, and social network service) on smartphone, the demand of text input using a soft keyboard is increasing. However, studies on subjective and physiological responses of users for various touch locations are lacking. The present study investigated the ergonomic effects according to touch locations of a soft keyboard on smartphone. The experiment of the present study measured perceived discomfort using Borg's CR-10 scale and electromyography (EMG) on forearm (abductor pollicis longus, and extensor digitorum communis) and thumb (abductor pollicis brevis, and first dorsal interossei) muscles. Perceived discomfort was significantly varied from 0.7 (extremely weak discomfort) to 2.5 (weak discomfort) depending on touch locations. %MVC according to touch locations was only significant at abductor pollicis brevis which varied from 10% to 23%. The experimental results of the present study can be utilized in the ergonomic design of a soft keyboard.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.169-175
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• 2024

In this paper, we introduce a novel approach to enhance document security by integrating Computer Generated Hologram(CGH) encryption technology with a system for document encryption, printing, and subsequent verification using a smartphone application. The proposed system enables the encryption of documents using CGH technology and their printing on the edges of the document, simplifying document verification and validation through a smartphone application. Furthermore, the system leverages high-resolution smartphone cameras to perform online verification of the original document and supports offline document decryption, ensuring tamper detection even in environments without internet connectivity. This research contributes to the development of a comprehensive and versatile solution for document security and integrity, with applications in various domains.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.289-297
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• 2014

The purpose of this study was to investigate the relation between smartphone addiction and interpersonal competence of college students using social network service(SNS) through smartphones. This study used a descriptive study design. The convenience sample consisted of 502 college students in six cities. The data were collected from May to June in 2012 using Korean Smartphone Addiction Proneness Scale and Interpersonal Competence Questionnaire. Descriptive statistics, ${\chi}^2$-test, t-test, analysis of variance, and Pearson correlation coefficient were used to analyze the data. The results showed that 24.8% of SNS users were considered as a risk group, while 75.2% were normal user group. There were no significant differences of interpersonal competence between risk group and normal user group in the SNS users. However, risk group had higher self-disclosure scores than normal user group. The subjects who had higher scores for virtual life, one of smartphone addiction subdomains, had lower interpersonal competence and those with higher smartphone addiction scores showed lower score of managing interpersonal conflict in subdomains of interpersonal competence. These findings would contribute in development of preventive interventions for smartphone addiction and improvement program for interpersonal competence in college students.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.121-129
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• 2017

The purpose of this study was to examine the mediating effects of experiential avoidance on the relationships between life stress, depression and smartphone addiction in nursing college students. This study was conducted using a descriptive survey design. Participants were 283 nursing college students attending freshmen and sophomore yearsat one university in Jeollanam-do. Data were collected from September 1 to 15, 2015 using self-report questionnaires. Data were analyzed using descriptive statistics, Pearson's correlation coefficient, hierarchical regression and Sobel test with SPSS 21.0. There were significant positive correlations between life stress, depression, smartphone addiction and experiential avoidance. Experiential avoidance partially mediated the relationship between life stress and depression of nursing students. Additionally, experiential avoidance partially mediated the relationship between their life stress and smartphone addiction. The results show that experiential avoidance plays a key role in psychopathology and grows with depression and smartphone addiction. Based on the present findings, nursing interventions should be developed to decrease experiential avoidance, with additional consideration towards the relationship between life stress and experiential avoidance, in order to prevent depression and smartphone addiction among nursing college students.

• Journal of The Korean Ophthalmological Society
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• v.58 no.11
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• pp.1313-1316
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• 2017

Purpose: To report fundus photography using a smartphone in an infant with abusive head trauma. Case summary: An 8-month-old male infant presented to the emergency room with decreased consciousness and epileptic seizures that the parents attributed to a fall from a chair. He had no external wounds or fractures to the skull or elsewhere. However, computerized tomography of the brain revealed an acute subdural hematoma in the right cranial convexity and diffuse cerebral edema, leading to a midline shift to the left and effacement of the right lateral ventricle and basal cistern. The attending neurosurgeon promptly administered a decompressive craniectomy. Immediately after the emergency surgery, a fundus examination revealed numerous multi-layered retinal hemorrhages in the posterior pole extending to the periphery in each eye. He also had white retinal ridges with cherry hemorrhages in both eyes. We acquired retinal photographs using the native camera of a smartphone in video mode. The photographer held the smartphone with one hand, facing the patient's eye at 15-20 cm, and held a 20 diopter condensing lens at 5 cm from the eye in the other hand. Our documentation using a smartphone led to a diagnosis of abusive head trauma and to obtain the criminal's confession, because the findings were specific for repetitive acceleration-deceleration forces to an infant's eye with a strong vitreoretinal attachment. Conclusions: This ophthalmic finding had a key role in the diagnosis of abusive head trauma. This case presented the diagnostic use of a smartphone for fundus photography in this important medicolegal case.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.1
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• pp.21-29
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• 2023

Purpose : Using a smartphone while walking districts attention and increases the risk of losing balance or falling. Ankle instability is caused by decreased muscle strength and decreased neuromuscular ability leading to postural control problems. Dual tasks increases the risk of falls by reducing postural control in adults with ankle instability. This study aimed to investigate the effect of performing a dual task on balance and muscle activity in adults with ankle instability using a smartphone. Methods : Forty-nine individuals with ankle instability participated in this study. A game of finding the wrong picture was performed using a smartphone in the dual task, and only looking at the blank screen of a smartphone was evaluated in the single task. The participants randomly performed single and dual task to evalutate balance and muscle atcitivy. Balance was evaluated using the Biodex balance system (BBS), and muscle activity was evaluated using surface EMG. Muscle activity of the gastrocnemius and tibialis anterior was measured at the same time as balance. Results : The results of this study showed that overall, anteior/posterior, and medial/lateral balance indices all showed significant differences when performing the dual task compared with those during the single task (p<.05). The muscle activity results showed a significant difference compared with that of the gastronemius muscle on the nondominant side during the dual task (p>.05). Conclusion : The results of this study showed that maintaining balance is more difficult when performing the dual task than during the single task, and only the muscle activity of the nondominant gastrocnemius muscle decreased. The dual task causes a decrease in concentration for postural control, which negatively affects postural stability. Individuals with ankle ankle instability should refrain from performing dual tasks, such as using smartphones, to prevent ankle damage.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.61-67
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• 2018

This study was conducted to ascertain the mediating effects of aggression in high school students' relationship with smartphone overuse and cyberbullying. Data were collected from 328 high school students in K city using self-report questionnaire. The collected data were analyzed using SPSS 22.0 and AMOS 22.0. The results show that cyberbullying has a positive correlation with smatrphone overuse(r=.321, p<.001) and aggression(r=.397, p<.001). Smartphone overuse had a direct effect on aggression(${\beta}=.195$, p=.014) and aggression had a direct effect on cyberbullying(${\beta}=.260$, p=.007). In addition, the mediation effects of aggression on the relationship between smartphone overuse and cyberbullying were confirmed(${\beta}=.051$, p=.007). In order to reduce cyberbullying in high school students, it will be necessary to develop cyber ethical awareness education programs to reduce aggression as well as regulations on excessive use of smartphones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.139-146
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• 2014

This paper proposes a new personalized mobile advertising service using a smartphone connected with a digital signage which is increasingly common for out-of-home advertising. The advertising contents can be transferred with their metadata to a digital signage. Then, the signage delivers only metadata to smartphones in close proximity of it. Based on the user's preference, an application on a smartphone stores advertising metadata and publishes a personalized advertising e-catalog automatically. A smartphone user can browse, edit and share it with friends. In the view of extension of the reach of the advertising contents of various N-Screen devices including a digital signage and a smart TV to a smartphone and supplying personalized advertising data, this advertising model will be very beneficial and commercialized in the near future.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.19-26
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• 2018

Social issues for environmental pollution are continuously increasing globally. Especially, Users require services to measure environmental factors in indoor and outdoor and manage related data effectively and conveniently. According to this demand, sensors that can measure environmental factors in indoor and outdoor have been developed. However, since one sensor is composed of independent module, the interface of output data from each sensor is different. To solve the problem, we propose a customized protocol for low-power short-range wireless communication between smartphone using Bluetooth and All-in-One sensor device board and analyze the performance of the proposed customized protocol by developing program for performance verification of interface with user smartphone through Bluetooth. In addition, we implement a smartphone application using proposed protocol.