• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.578-589
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• 2014

In this paper, we introduce the concept of cyber-physical intersection systems (CPIS) which interconnects roadside units (RSU) located at the intersection, on-board units (OBU) of moving vehicles, and the smartphone apps, named the Smartphone Agent (SA). At the pedestrian mode of the SA, the connectivity management schemes, such as a location update and a handover control algorithm, are proposed to better support the CPIS services while minimizing the power consumption of the pedestrian's smartphone. We develop a real prototype of the CPIS, including RSU, OBU, and the SA. Based on the numerical results collected from a pedestrian moving around the Pusan National University campus, we validate that the proposed connectivity management schemes can improve not only the power efficiency of the pedestrian's smartphone, but also the quality of the CPIS services.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.197-204
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• 2019

The purpose of this study was to explore factors that influence decision making for smartphone users. This study sets intimacy, personal connection, use & dependence, familiarity and expertise, efficacy and effectance, self-identity, and control as independent variables and sets decision making as dependent variables. In this study, 200 smartphone users were collected and analyzed through questionnaires, and Smartpls 3.0 was used to understand the impact between variables. Five of the six factors that affected smartphone users' psychological strength were analyzed to have affected their decision-making. In addition, we examined the relationship between psychological effects and use period as a control variable. The results of this study can be used as a basis for the consumer behavior of smartphone devices in the development of smartphone devices.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.22-31
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• 2012

A Smartphone is an intelligent device combined mobile phone and pc's support functions, and can perform multiple functions to satisfy the demands of users. It has excellent processing power and communication modules(DMB, Wi-Fi, Bluetooth, NFC etc) to carry out the demands of users. But continuous using of battery power on processor and equipped modules causes acceleration of battery consumption. This means that effective power management in devices like smartphone is important. Therefore, the management of power consumption on system execution and communication module is a serious issue in this field of study. In this paper, we would like to propose a communication module selection algorithm based on energy consumption parameter of each communication module and data transfer time. Our scheme automatically select appropriate communication system to reduce high energy consumption on bluetooth sleep mode so that this scheme is more efficient and effective thus improving user convenience in longer usage time. Experimental results showed the 20% energy saving.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.378-379
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• 2012

Nowadays, great energy consumption in advanced electrical industry has called up the great y efficiency. Electric power IT industry such as intelligent electric power system is receiving great attention and being marked up as a new growth engine. Through Intelligent electric power system, the electric power supply can be balance optimized according to demand, giving huge cost savings advantage for energy imports, infrastructure construction and operation. Nevertheless, the intelligent system promotes better reliability in power supply. Manual electric power management using man power appears to be non-practical. Real time electric power management on all facilities and equipment can be done through an intelligent electric power system, any accident break out issue can be easily recorded and recognized. In this paper, a fully integrated intelligent switchgear electric management system is developed to monitor and remote control the electrical switch based on smart phone. The proposed system is superior than the existing switchgear management system's weakness and can sharply improve effectiveness and stability with low cost. In future, the proposed system is expected to be greatly contributed to the advancement of the IT industry in electric power management.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.762-767
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• 2015

An Internet of Things (IoT) is a system where various "things" are connected to each other via a wired/wireless network, and where information is gathered, processed, and interchanged/shared. One of the important actors in IoT is a mobile IoT device (such as a smartphone or tablet). These devices tend to consume a large amount of power in order to provide various high performance application services; however, as the devices cannot be supplied with power all the time, efficient power management is necessary. Power management of mobile IoT devices involves complex relationships between various entities such as application processors (APs), HW modules inside/outside AP, operating systems, mobile IoT platforms, and applications. In order to develop power-efficient mobile IoT devices, a method is needed to systematically analyze these relationships and manage power based on a clear understanding of them. To address this problem, software engineering principles for the development of power-efficient mobile IoT devices are presented in this paper. The feasibility of the proposed principles have been validated in the domain of smartphone camera power management.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.4
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• pp.270-275
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• 2005

As the features of mobile phones are being enhanced and the performance is being greatly improved, the generic operating systems are being incrementally used in mobile phones. However, since the mobile phones have different requirements in both features and performance compared with desktop or server systems, the operating systems for generic systems could not be used without customization and modification. This case study paper describes the design and implementation of a Linux-based smartphone hardware and software. The enhancements and additional implementations in both kernel and middleware layers are explained. As an experiment, the power consumption of the implemented mobile phone under a number of user scenarios has been measured.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.22-34
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• 2012

In this paper, we design and implement an advanced cattle shed management system using a infrared wireless sensor nodes and surveillance camera. Our system provides three main capabilities, such as 24-hours cattle shed monitoring, trespassing detection, automatic control of cattle shed. For this, our system can monitor cattle shed as well as the condition of cows/bulls for 24 hours per day by using surveillance cameras. Our system also can detect intruders inside the cattle shed by using infrared wireless sensor nodes. In addition, our system can control the power of electric equipments in the cattle shed by using a power controller. Finally, we combine the three components into a system by using a smartphone application program and verify the effectiveness of our system by a testbed.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.1
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• pp.29-34
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• 2021

We developed a pet care robot that can be controlled outdoors. Through the smartphone application, the pet owners can watch the situation in the house and manipulate the robot to make their pet happy. The video data in the house is transmitted to the application through the webcam installed at the house. The robot can not only perform user's command but also do six basic macro action. The obstacle avoidance function using the current sensor can be activated if the user want to use. When the robot hits to something, it moves back and rotates by arbitrary angle, and then moves forward.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.328-333
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• 2017

Mobile game apps, which are popular in various mobile devices, tend to be power-hungry and rapidly drain the device's battery. Since a long battery lifetime is a key design requirement of mobile devices, reducing the power consumption of mobile game apps has become an important research topic. In this paper, we investigate the power consumption characteristics of popular mobile games with multiple threads, focusing on the inter-thread. From our power measurement study of popular mobile game apps, we observed that some of these apps have abnormally high-load threads that barely affect the user's gaming experience, despite the high energy consumption. In order to reduce the wasted power from these abnormal threads, we propose a novel technique that detects such abnormal threads during run time and reduces their power consumption without degrading user experience. Our experimental results on an Android smartphone show that the proposed technique can reduce the energy consumption of mobile game apps by up to 58% without any negative impact on the user's gaming experience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.398-407
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• 2017

This study examined the relationship among smartphone addiction, life stress, and family communication in nursing students. A total of 172 subjects participated in this study and the data were collected using the structured questionnaires. The collected data were analyzed using an independent t-test, ANOVA, Pearson's correlation coefficient, and multiple linear regression using the SPSS WIN 19.0 program. Overall, the level of stress was high, time of family communication was short, and smartphone addiction rate was high in nursing students. The high risk group of smartphone addiction was 14.0%, potential risk group was 29.0%, and normal group was 57.0%. In the risk group, the life stress was higher (t=3.15, p=.002) and family communication was not better (t=-2.53, p=.012) than the normal group. Smartphone addiction correlated significantly with life stress (r=.27, p<.001) and family communication (r=-.26, p=.001). The factors affecting smartphone addiction were smartphone usage time, life stress, importance of smartphones in their lives, and family communication, and the explanatory power was 31.3%. Based on these results, it is necessary to develop personalized and collective customized intervention programs focused on smartphone using method, life stress management, and family communication for the prevention and management of smartphone addiction of nursing students.