• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.915-924
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• 2012

Though a mobile device is equipped with a number of wireless communication interfaces in general such as Zigbee, Bluetooth, Wi-Fi, 3G, it uses only one interface for a specific service. In this paper, we propose a mechanism of adaptive switching between wireless communication interfaces in order to efficiently use various communication interfaces. Depending on the application service and the characteristics of wireless communication interface, mobile devices select an appropriate wireless communication interface and may switch to another interface during the service. As a result, power consumption can be reduced and the utilization of communication interface can be improved by using this mechanism.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.205-206
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• 2015

스마트폰이 유선전화의 단말기가 되면 스마트폰의 전화번호부를 유선통화에도 사용할 수 있게 되어 유선전화의 사용량이 늘어나고, 이를 통해 사용자는 통신요금이 낮아지는 혜택을 누리며 유선 사업자는 수익 증대를 기대할 수 있다. 그러나 이동통신용 단말기로 제작된 스마트폰을 유선전화의 단말기로 이용하는 데는 i) 사용자 편의성 증대를 위한 스마트폰 등록 절차의 간소화, ii) 저전력 상태와 WiFi 비활성화 상태에서 전화수신 안정화, iii) 무선데이터 전송시간 변이에 의한 음성품질 저하 회피 등 다양한 기술적 문제들이 존재한다. 본 논문에서는 이와 같은 문제들에 대한 해결 방안을 제시하고 이를 반영한 실험용 시스템의 구현 결과를 보여준다. 실험용 시스템은 사설교환기 기능을 내장한 WiFi-AP, 안정적인 전화수신 알림을 위한 PUSH broker, VoIP 어플리케이션이 설치된 스마트폰으로 구성된다. 실험용 시스템은 PSTN 망과 VoIP 망에 연동하여 스마트폰으로 안정적인 통화품질을 제공할 수 있음을 보였다.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.9-17
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• 2019

In this article, we present a performance enhancement scheme for mobile applications by adopting persistent memory. The proposed scheme supports the deadline guarantee of real-time applications like a video player, and also provides reasonable performances for non-real-time applications. To do so, we analyze the program execution path of mobile software platforms and find two sources of unpredictable time delays that make the deadline-guarantee of real-time applications difficult. The first is the irregular activation of garbage collection in flash storage and the second is the blocking and time-slice based scheduling used in mobile platforms. We resolve these two issues by adopting high performance persistent memory as the storage of real-time applications. By maintaining real-time applications and their data in persistent memory, I/O latency can become predictable because persistent memory does not need garbage collection. Also, we present a new scheduler that exclusively allocates a processor core to a real-time application. Although processor cycles can be wasted while a real-time application performs I/O, we depict that the processor utilization is not degraded significantly due to the acceleration of I/O by adopting persistent memory. Simulation experiments show that the proposed scheme improves the deadline misses of real-time applications by 90% in comparison with the legacy I/O scheme used in mobile systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.626-629
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• 2021

Recent home appliances requires convenience and low-power consumption. A convenient devices should be simple to control while having several functions. Intelligent sensors and utilization technologies are required to reduce energy consumption. This paper provides a smart drying system with Bluetooth communication function and energy reduction function. Design a control system that uses the Bluetooth function so that the smartphone monitors the drying control and the internal humidity condition. By detecting the humidity inside the dryer and controlling the speed of the motor, it has an energy-saving function.

• The Korean Journal of Food And Nutrition
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• v.27 no.6
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• pp.1096-1106
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• 2014

This study was conducted to figure the usage status and satisfaction of food-related smartphone applications by generic characteristics and food purchase attributes of Seoul area workers. The results show that health vitality-oriented group, married compared to single, those with higher eating-out expenses possess more food-related applications (p<0.05). The primary reason for the usage of food-related applications was the need for food-related information (53.7%). The highest application subjects in use were restaurant-related information and recipe information. The real-life aid food-related applications utilized most were also restaurant information (60.7%) and recipe information (28.3%). Health vitality-oriented respondents especially turned out to use nutrition information and food functionality information often (p<0.01), and recipes or calories & diet information usage frequency was higher in women than in men (p<0.001). Restaurant-related information were more frequently used by singles, highly educated, and those with high income and eating-out expenses (p<0.05). Satisfaction of food-related applications was normal (3.06), showing that the satisfactory level is not yet high. Satisfaction regarding purchase attributes showed that the health vitality-oriented group (3.19) was more satisfied compared to other groups (p<0.05), and women (3.16) were more satisfied that men (2.89) were (p<0.05). Inconveniences of food-related applications were highest in usage fee (3.29), simplicity of information (3.28), lack of reliability of information and need for update (3.10). The results of this study implies that various subdivisions of food-related applications users should be implemented; at the same time, food-related applications covering diverse subjects that regard each group's characteristics should be developed in order to utilize food-related knowledge and information as a marketing tool in the food industry; this can efficiently be done by paying attention to the quality of information and updates within applications.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.753-759
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• 2011

Protected crop production has been popular in Korea as well as in other countries. Intensive and continuous monitoring and control of the environment, which is labor- and time-consuming, is critical for stable crop productivity and profitability, otherwise damage could be happened due to unfavorable ambient and soil conditions. In the study, potential utilization of smartphone and remote access application in protected crop production environment was investigated. Tested available remote access applications provided functions of mouse click (left and right buttons), zooming in and out, and screen size and color resolution control. Wi-Fi data communication speeds were affected by signal intensity and user place. Data speeds at high (> -55 dBm), medium (-70~-56 dBm), and low (< -71 dBm) signal intensity levels were statistically different (${\alpha}=0.05$). Means of data communication speed were 6.642, 4.923, and 2.906 Mbps at hot spot, home, and office, respectively, and the differences were significant at a 0.05 level. Smart phone and remote access application were applied successfully to remote monitoring (inside temperature and humidity, and outside precipitation, temperature, and humidity) and control (window and light on/off) of green house environment. Response times for monitoring and control were less than 1 s at all places for high signal intensity (> -55 dBm), but they were increased to 1 ~ 10 s at home and office and to 10 ~ 30 s at hot spot for low signal intensity (< -71 dBm) for Wi-Fi. Results of the study would provide useful information for farmers to apply these techniques for their crop production.

• The Journal of Korean Association of Computer Education
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• v.18 no.2
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• pp.1-9
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• 2015

Excessive cognitive burdens caused by learning grammar should be reduced to cultivate high-level thinking skills in students through programing education. To this end, various educational programing languages have been developed. In recent years, block-based App Inventor that can used in real life have been introduced. This study intends to suggest an educational environment in which programing can be utilized as a leading problem solving tool by designing and producing an app that can be easily used by students in their real life. In particular, given the developmental phase of elementary school students, specific operational activities are important. For this reason, an App Inventor that can be proposed to enable dynamic interactions with the real world based on various smartphone sensors during the process of programing has significance as an educational programing language for elementary school students. In this regard, this study designed App Inventor programing education for elementary school students, which can be used in their daily life. The results of applying the education in fifth graders showed its positive effects on learning programing. LT collaborative learning where the students cooperated with each other, the theme of learning, which enables the utilization of various smartphone sensors in real life, and the app inventor may have generated and sustained the students' interest and attention.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.137-141
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• 2012

The foot and mouth disease(FMD) was occurred from Andong city on November 23, 2010 and spread out the whole country except Jeju island and Jeolla-do. About 3.4 million livestock such as cow and pig was buired at 4,200 sites during preventive measures of FMD. Government did not effectively respond to the FMD crisis management so FMD spread out the whole country. To Prevent the spread FMD, Farms have to fast approaching and respond directly to smartphones and Tablet PC applications. Resolve the difficulties of using smart devices and easy to operate for the effective utilization of the development of simple applications. This application of FMD, developed for the prevention and alarm applications, foot and mouth disease will be caused, farmers around the farm in case of risk and the seriousness of the FMD will notify smartphone, FMD prevent additional damage due to be interested in preventing further that allows your application is for development purposes.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.189-200
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• 2022

In today's digital world, smartphones and web-based applications have gained remarkable importance throughout the globe. These smart applications are playing a very significant role in maintaining a powerful business. As well as, they are helping a lot to expand these businesses via social networks. Social media networks such as Instagram, Facebook, Twitter, and LinkedIn are playing a prominent role to promote the companies. In the hospitality sector, most of the companies are running their hotel booking systems by utilizing mobile applications and a web-based infrastructure, but usability issues still exist. This study has been conducted specifically to tackle the usability issues of hotel booking systems and the best utilization of social networks to promote the business. TripAdvisor was selected as an authentic source for selecting those systems and two international hotels are selected for this study. The first step is to identify different hotel booking systems. In the second step, the user's satisfaction level was measured for the selected systems by performing the System Usability Scale (SUS, Quick & Dirty) approach. Additionally, by which source (social media or personal relations) they found these hotels. It is found that the SUS rating for both systems is below the acceptable level of usability. The Mean SUS for hotel 1 is found at 55.25 and 51.2 for hotel 2. The third step was to identify the user interface (UI) issues, and heuristic evaluation is performed for this. The experts identified the UI issues on the basis of their experience. The major issues were related to the visibility of system status, error prevention, flexibility and efficiency of use. Depending upon the identified issues, an interactive UI (prototype) for the selected web-based applications was proposed. This prototype is mainly based on the user's perspective. This prototype can be used for improving the UI of the selected systems which is based on the user's perspective. During the process of verifying the satisfaction level, it is revealed that the targeted audience is not able to use these systems efficiently and effectively. The reason behind this is the negligence of usability guidelines throughout the process of design and development of these hotel booking systems. Therefore, it is highly recommended that the usability of these systems should be evaluated and redesigned, based on expert opinions. It has also been observed that the reviews/ feedback of customers has spread a negative impact through social networks.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.6
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• pp.55-66
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• 2016

Power gating is one of effective techniques for reducing leakage current in semiconductor chip. However, power gating cell (PGC) which is used to switch the power source causes performance degradation and the associated reliability problem by increasing IR drop. However, the newly raised problem caused by different scaling properties between gates and metal wires demands additional considerations in power gating design. In this paper, we propose a robust cell placement based power gating design method for reducing the area for power gating cell and metal routing thus to meet IR drop requirement. Experimental results by applying the proposed techniques on the application processor for smartphone fabricated in 28nm CMOS process show that power gating cell area is reduced by 16.16% and maximum IR drop value is also decreased by 8.49% compared to existing power gating cell placement techniques.