• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.1
• /
• pp.149-153
• /
• 2020

This paper presents a new page placement policy for DRAM/NVRAM hybrid main memory in smartphones. Unlike previous studies on hybrid memory systems, this paper performs the placement of pages based on the offline analysis of memory access behaviors as smartphone's memory accesses are skewed to a certain address ranges, which is consistent regardless of smartphone applications, specially for write operations. Thus, we aim at reducing the write traffic to NVRAM by the offline analysis results. Experimental results show that the proposed policy reduces the write traffic to NVRAM by 61% on average without performance degradations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.8
• /
• pp.692-698
• /
• 2013

As the mobile marketing through the smartphone has gradually increased, the smartphone application services using the AR marker, QR codes and augmented reality have attracted much attention. Furthermore the outdoor advertising is migrated to LED signage, which brings the visible light wireless communication technologies to the trial for mobile marketing. In this paper we present the implementation of AR marker-based URL access application services through smartphone camera using visible-light wireless communication technologies. We analyze the performance of the implemented system in terms of connection time and success rate.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.12
• /
• pp.1-10
• /
• 2012

In this paper, we propose an patient monitoring system which is suitable for mobile healthcare system. The mobile healthcare system is using portable device such as smartphone and it consists of small computing device. The mobile healthcare system is carry out same performance with desktop computer. We designed medical message structure based on TinyOS to transmit patient's biometric data on the smartphone of medical team, patient and family over the mobile carrier environment, and ported successfully in HBE-Ubi-ZigbeX using NesC. And We confirmed reliable transmission of biometric data on the smartphone by implementing the Android OS based patient information monitoring application to check the status of patient for medical team, patient and family.

• KIPS Transactions on Software and Data Engineering
• /
• v.3 no.2
• /
• pp.87-92
• /
• 2014

In this paper, we present a two-phase activity recognition system using smartphone's accelerometers. To consider the unique temporal pattern of accelerometer data for each activity, our system executes the decision-tree(DT) learning in the first phase, and then, in the second phase, executes the hidden Markov model(HMM) learning based on the sequences of classification results of the first phase classifier. Moreover, to build a robust recognizer for each activity, we trained our system using a large amount of data collected from different users, different positions and orientations of smartphone. Through experiments using 6720 examples collected for 6 different indoor activities, our system showed high performance based on its novel design.

• The Journal of the Korea Contents Association
• /
• v.10 no.12
• /
• pp.155-163
• /
• 2010

Due to the complex registration & downloading process of the native applications, and, software and their non-standardized APIs, mobile web application is now being an alternative software for smartphones. Hybrid web application, one of the types of mobile software, because develop and has reasonable performance by using the webkit engined in smartphones. It can be easily developed by using the exiting programming skill such as HTML, JavaScript and CSS. Additionally these programming techniques can be easily used in any smartphone regardless of its platforms. Most smartphones have a webkit engine or web rending engine for high performance and smooth display in web browser. Webkit is now equipped in iPhone and Android phone. In this paper, we try to find out by comparison that the various aspects of webkit APIs of iPhone & Android phone, such as screen font size, screen orientation, touch event, gesture event and their performance. We also evaluated which one is more convenient for developers when making web programs using webkit. As a result, we found out that webkit in iPhone has more excellent performance than Android.

• Journal of Positioning, Navigation, and Timing
• /
• v.7 no.4
• /
• pp.217-226
• /
• 2018

According to the Korea Coast Guard's maritime disaster statistics (Korea Coast Guard 2017, Korean Statistical information Service 2018), an average of 2,140 marine accidents occurred every year for the past 6 years and the number of accidents is increasing every year. Among them, maritime accidents of fishing vessels are the most frequent, and recently accidents involving fishing boat and leisure vessels are rapidly increasing as well. In particular, the number of accidents involving leisure vessels increased to about one-third of the accidents of fishing vessels, and emergency rescue requests are increasing every year accordingly. However, the number of crash accidents involving users of small vessels and marine leisure activities are increasing because of the difficulties of installing navigation equipment and electronic navigation charts. Recently, the demand for precise positioning using mobile devices is increasing in the fields of maritime safety, piloting support, and coastal survey. Although various applications of smart devices provide location-based services for users, the measurement results are discontinuous when using the position coordinates of the National Marine Electronics Association (NMEA) calculated by smartphone. Recently, Google announced that they will provide GPS raw data to developers from Android 7.0 Nougat. As a result, developers have an opportunity to receive precise carrier phase and code measurements to make more accurate positioning according to the performance of Android devices. This study analyzed GPS positioning performance using Android devices, and compared and analyzed the positioning performance at sea with high-performance GPS receivers.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.3
• /
• pp.412-418
• /
• 2021

This study aims to investigate the influence of emotional engineering factors on brand preference and loyalty in smartphone product design. The emotional engineering factor was divided into color, performance, usability, value, and reliability, and the relationship between brand preference and loyalty was empirically analyzed. As a result of the analysis, the emotional engineering factor in the smartphone product design has a positive effect on the brand preference, and the factors having the greatest influence are the performance and color factors. In smartphone product design, the emotional engineering factor has a static effect on loyalty, and the factors that have the greatest influence are reliability and performance factors. The higher the brand preference in product design, the greater the affect on loyalty. It is necessary to approach product design that fits the characteristics of consumers by identifying the influential factors among the product design emotional engineering factors.

• East Asian Journal of Business Economics (EAJBE)
• /
• v.6 no.3
• /
• pp.16-23
• /
• 2018

Purpose - 2013 to 2014 was a transitional situation in which China's Smartphone industry was fluctuating. So in this paper, we will look at the strategies and achievements of Xiaomi, a company that has emerged in this situation and topped the market share. In particular, the purpose of this paper is to analyze why Xiaomi, which is considered a copycat, was able to succeed in the smartphone market four years after entering the market and analyze its strategy. Research design and methodology - Various secondary data are to be used for this study. Using various newspaper articles as well as corporate reports, the company analyzes the transitional situation from 2013 to 2014 and the competitors together. Through these analyses, Xiaomi's strengths are selected objectively and analyzed to identify the factors that made Xiaomi successful. Results - After China's transitional shift in 2014, Xiaomi brought about a 152.3 percent share change over the previous year. In addition, it surpassed Samsung Electronics, which has been the industry's No. 1 player, in 2014, and achieved the No. 1 ranking with a 16 percent share. Xiaomi Mi4's phone had a strong point of maintaining low price while being loaded with high performance. Conclusions - Xiaomi's success is because its price and performance was excellent. Xiaomi's Mi4's specifications were not far behind its competitors', but it was very cheap compared to its competitors' prices. They also valued software and used talent-oriented human resource strategies. Plus, it created the 'Mifan' culture successfully and benchmarked the strengths of its competitors smartly.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.7
• /
• pp.45-55
• /
• 2021

Information obtained through various sensors embedded in a smartphone can be used to identify and analyze user's movements and situations. In this paper, we propose two rule-based motion detection systems that can detect three alphabet motions, 'I', 'S', and 'Z' by analyzing data obtained by the acceleration and gyroscope sensors in a smartphone. First of all, the characteristics of acceleration and angular velocity for each motion are analyzed. Based on the analysis, two rule-based systems are proposed and implemented as an android application and it is used to verify the detection performance for each motion. Two rule-based systems show high recognition rate over 90% for each motion and the rule-based system using ensemble shows better performance than another one.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.9
• /
• pp.797-801
• /
• 2013

Visible light communication (VLC) is a rapidly growing area of research and applications, due to the potential and predicted high efficiency of bandwidth. One of the key challenges in VLC technology is the choice of devices which are going to be deployed VLC features. Smartphone rationally uses the most widely deployed visible light sensor i.e. image sensor in camera, which could be used to receive the intensity modulated data. Image sensor based VLC system would be the most deployable scenario but initially the capacity was not much attractive compared with photodetector based VLC system. Here, the spatial multiplexing is proposed in MIMO based VLC system to increase the system capacity by utilizing the property of spatial separation of optical light sources in smartphone's camera module. The active pixels of imaging plane act as the multiple receivers which could be able to use on MIMO spatial multiplexing to enhance the system performance.