• Smart Structures and Systems
• /
• v.31 no.2
• /
• pp.141-154
• /
• 2023

After an earthquake, information regarding potential damage to buildings close to the epicenter is very important during the initial emergency response. This study proposes the use of crowdsourced measured acceleration response data collected from smartphones located within buildings to perform system identification of building structures during earthquake excitations, and the feasibility of the proposed approach is studied. The principal advantage of using crowdsourced smartphone data is the potential to determine the condition of millions of buildings without incurring hardware, installation, and long-term maintenance costs. This study's goal is to assess the feasibility of identifying the lowest fundamental natural frequencies of buildings without knowing the orientations and precise locations of the crowds' smartphones in advance. Both input-output and output-only identification methods are used to identify the lowest fundamental natural frequencies of numerical finite element models of a real building structure. The effects of time synchronization and the orientation alignment between nearby smartphones on the identification results are discussed, and the proposed approach's performance is verified using large-scale shake table tests of a scaled steel building. The presented results illustrate the potential of using crowdsourced smartphone data with the proposed approach to identify the lowest fundamental natural frequencies of building structures, information that should be valuable in making emergency response decisions.

• Industrial Engineering and Management Systems
• /
• v.13 no.4
• /
• pp.408-413
• /
• 2014

The QWERTY type keyboard is a classical device that has been used for computers for a long time. The keyboard design of mobile devices like smartphones is an important issue to consider because of the limited space on the touch screen. This paper presents a design for symbol allocation on the QWERTY type soft keyboard. A 27-cell model, including the full stop (.), is proposed in this paper. A QWERTY type keyboard for smartphones is mainly known for its spatial compatibility, whereas the characters of the ANSI keyboard are allocated to the shoulder positions for functional auxiliary input methods such as the long pressing method.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.2
• /
• pp.223-231
• /
• 2015

As smartphones support a variety of applications and their memory demand keeps increasing, the design of an efficient memory management policy is becoming increasingly important. Meanwhile, as nonvolatile memory (NVM) technologies such as PCM and STT-MRAM have emerged as new memory media of smartphones, characterizing memory references for NVM-based smartphone memory systems is needed. For the deep understanding of memory access features in smartphones, this paper performs comprehensive analysis of memory references for various smartphone applications. We first analyze the temporal locality and frequency of memory reference behaviors to quantify the effects of the two properties with respect to the re-reference likelihood of pages. We also analyze the skewed popularity of memory references and model it as a Zipf-like distribution. We expect that the result of this study will be a good guidance to design an efficient memory management policy for future smartphones.

• Journal of Information Technology Services
• /
• v.12 no.2
• /
• pp.269-289
• /
• 2013

The tremendous advancement of technology sparked a lot of opportunities for developers and consumers to pave way to a dynamic application market in smartphones. This study focuses on the users' perspective, that is, the preference between two application markets that varies in many perspectives of its features. Hence, the purpose of this study is to provide a comparative study on two mobile application stores in smartphones; Google Play and T-Store. A survey was conducted to compare the markets, and the results showed the different influencing factors on choosing and using each application store. In addition, the results somehow revealed the harmony of co-existence in smartphones.

• Journal of Computational Design and Engineering
• /
• v.2 no.2
• /
• pp.73-78
• /
• 2015

In this paper, we propose a new approach to providing interactive and collaborative lens among multi-users for supporting level-of-detailed views using smartphones in a public display. In order to provide smartphone-based lens capability, the locations of smartphones are effectively detected and tracked using Kinect, which provides RGB data and depth data (RGB-D). In particular, human skeleton information is extracted from the Kinect 3D depth data to calculate the smartphone location more efficiently and correctly with respect to the public display and to support head tracking for easy target selection and adaptive view generation. The suggested interactive and collaborative lens using smartphones not only can explore local spaces of the shared display but also can provide various kinds of activities such as LOD viewing and collaborative interaction. Implementation results are given to show the advantage and effectiveness of the proposed approach.

• Journal of Korean Institute of Industrial Engineers
• /
• v.40 no.1
• /
• pp.100-107
• /
• 2014

This paper presents a co-located and mobile interaction technique using smartphones in a global space. To effectively detect the locations and orientations of smartphones, the proposed approach utilizes Kinect that captures RGB image as well as 3D depth information. Based on the locations and orientations of smartphones, the proposed approach can support direct, collaborative and private interactions with the global space. Thus, it can provide more effective mobile interactions for local space exploration and collaboration.

• Journal of the Korea Convergence Society
• /
• v.8 no.1
• /
• pp.139-148
• /
• 2017

This convergence research was conducted to understand the effect of university students' addiction to smartphones on self-esteem and self-efficacy, with stress level and mental health as the parameters. The subjects were students from three universities located in J province, and 303 questionnaires were used as the data for analysis. The data were analyzed with Pearson's correlation, multiple regression and pathway analysis by SPSS and AMOS. As a result, addiction to smartphones showed negative (-) correlation with self-esteem, self-efficacy, and mental health, while showing positive (+) correlation with stress level. In addition, the addiction to smartphones has an influence on self-esteem and self-efficacy with stress level and mental health as the parameters. Therefore, in order to improve the self-esteem and self-efficacy of university students, programs should be developed to prevent and manage addiction to smartphones, relieve stress and promote mental health.

• Journal of the Korea Convergence Society
• /
• v.7 no.4
• /
• pp.163-172
• /
• 2016

This research was convergence study conducted to understand the effect that parent-son/daughter communications have on the addiction to smartphones, with stress level, self-control, and self-efficacy as the mediator. The subjects were college students located in J province and K province, and 232 questionnaires were used as the data for analysis. As a result, addiction to smartphones had negative correlations with parent-son/daughter communication, self-control, and self-efficacy and had positive correlations with stress level. In addition, parent-son/daughter communication influenced the degree of addiction to smartphones, with stress level, self-control, and self-efficacy as the mediator. Therefore, in order to reduce college students' addiction to smartphones, programs should be developed specifically and systematically to increase their communication with their parents, and it is necessary to draw up measures to reduce students' stress levels and increase their self-control and self-efficacy levels.

• Journal of the Korea Convergence Society
• /
• v.8 no.8
• /
• pp.315-323
• /
• 2017

This convergence research was conducted to understand the effect of university students' addiction to smartphones on self-efficacy, with lack of sleep and interpersonal relationships as the parameters. The subjects were students from three universities located in J province, and 263 questionnaires were used as the data for analysis. SPSS and AMOS were used for correlation analysis, multiple regression analysis, and path analysis. As a result, addiction to smartphones showed positive (+) correlation with lack of sleep, and negative (-) correlation with interpersonal relationships and sell-efficacy. In addition, the addiction to smartphones has an influence on self-efficacy with lack of sleep and interpersonal relationships as the parameters. Therefore, in order to increase the self-efficacy of unversity students, plans and measures should be prepared to manage and prevent addiction to smartphones and lack of sleep, and to improve interpersonal relationships.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.20 no.6
• /
• pp.67-81
• /
• 2010

As wide propagation of smartphones, e-commerce with smartphones increases rapidly. Such as transfer or stock trade systems. It has prospect that most of financial companies going to offer e-commerce systems via smartphones. And e-commerce via smartphones will be increased, hence the nature of smartphone that can be used whenever, wherever. However, legislation of e-commerce in Korea does not reflect these characteristics of smartphones, because it has set standards in regular PC. So that this study is security threat and feature of smartphones considering that the current legal system will use Certificate constraints, ensuring the safety of e-commerce and install security programs for protection of users, e-commerce responsible for the accident analysis has focused on the issues presented for this improvement.