• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.441-447
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• 2020

In a situation in which around 50 million metric tons of electrical and electronic products is generated globally per year, the total installed base of Internet of Things (IoT) devices is projected to amount to around 75 billion worldwide by 2025. However, there is very little research on identification schemes for end-of-life treatment (EoLT) of IoT devices. To address this issue, this paper proposes new identifiers including EoLT information such as recyclability rate (Rcyc) and recoverability rate (Rcov) of an IoT device, recycling rate (RCR) and recovery rate (RVR) of each part in the IoT device, etc. and implements them by using object identifier (OID), mobile radio frequency identification (RFID) and quick response (QR) code. The implemented OID and mobile RFID can be used with cooperation of a remote server via communication networks and the implemented QR code can be used simply with a smartphone app.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1596-1602
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• 2021

Battery-operated IoT devices in IoT systems require low power consumption. In general, IoT devices enter a sleep state synchronously to reduce power consumption. A problem arises when an IoT device has to handle asynchronous user requests, as the duty cycle must be reduced to enhance response time. In this paper, we propose a new low-power-consumption scheme, called Repetitive Wake-up scheme for IoT systems of asynchronous environments such as indoor lights control. The proposed scheme can reduce power consumption by sending wake-up signals from the smartphone repetitively and by retaining the IoT device in sleep state to the smallest possible duty cycle. In the various environments with IoT devices at home or office space, we showed that the proposed scheme can reduce power consumption by up to five times compared to the existing synchronous interlocking technique.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.35-40
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• 2023

In this paper, a serial wireless LAN virtual communication module that allows microprocessors to communicate wirelessly with other peripheral devices is developed as part of a study to build an online virtual experiment system that allows them to practice virtually anytime, anywhere in microprocessor application education in electrical and electronic control engineering. The developed module is connected to the microprocessor in the virtual experiment system through serial interface. The serial data is sent to and received from peripheral devices through the wireless LAN interface of the host computer where the virtual experiment software is being performed. In order to verify the function of the developed serial wireless LAN virtual communication module, experiments were conducted in which a microprocessor in the virtual experiment system exchanged data with an Android smartphone through a wireless LAN interface of a host computer. The developed serial wireless LAN communication module is expected to enable virtual microprocessors to communicate with surrounding real devices through wireless LAN, which can be efficiently used in microprocessor application education.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.93-99
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• 2021

Recently, the miniaturization and digitalization for the inspection devices of point-of-care testing (POCT) are rapidly evolving. In the urine test, a lot of researches on index paper technology are being conducted because people can be self-diagnosed through visual color comparison using a urine test paper, Dipsick. The purpose of this study is to analyze the RGB values from the color changes on Dipstick Pad, which isused for urine test, using a smartphone camera. To this end, the primary, analytes in urine wasdiabetes-related parameters such as glucose, ketone body and pH, which is the most frequently tested elements, and we pursuited to quantify the changes in dipstick color caused from artificial urine containing different ranges of sugar, ketone body, and pH. In this experiment, changes in RGB values under bright and dark illuminances were compared, and changes in RGB value were monitored as a function of concentration of analytes under the ambient illumination of laboratory. As a result, color separation at the bright luminance region was good, but it did not appearat the low luminance region, and the changed profiles in RGB value under different illuminances was suggested to correct the problem of the color separation algorithm.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.639-648
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• 2011

Since the emergence of the smartphone and tablet PC whose wireless internet accessibility has improved, personal computing environment has shifted from PCs to mobile web based mobile devices, and therefore the use of information and the communication method have been changing rapidly. Under the circumstance, domestic universities have actively been establishing mobile websites for smartphone users. Such mobile websites, however, focused on diverse functions and a showy design rather than on usability or accessibility, and were developed simply for the purpose of public relations. For this reason, students are now faced with difficulties in using the websites. Therefore, this paper proposes a novel web interface with the consideration of usability and accessibility in order for users to easily use and assess proper information. The matters to be taken into account in developing a mobile website are an intuitive interface design, user experiences, a user customized interface and compliance with web standards.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.620-625
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• 2017

Recently, the solar module for charging internet devices is installed in crowded areas to offers services so that people can charge their smartphones or tablets. But this charging module can not be linked with the information related to a bus approach so people are subject to let their belongings such as smartphone, tablet pc at the bus stop while they are still charging it. This paper proposes a system to inform the smart phone when the bus is accessed by using the LPWA technology and BLE technology to resolve such under-failures. This experimental result showed that the power usage of LPWA based bus entry systems is an average of X, confirming that the long period usage of low-power can be possible for low power consumption in this results, enabling information on the bus to be transmitted to smart phones using Advertising mode of BLE.

• The KIPS Transactions:PartD
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• v.19D no.4
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• pp.281-292
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• 2012

A wide variety of smartphone applications is increasing the usage time of smartphone. Due to the increased time, it becomes difficult to providing stable services to users with limited battery capacity. The past works have been performed the power management of mobile device toward long-lasting battery development or low-power electric devices. However as the complexity of software embedded into system are increased, the research interests of the software power analysis is also increased. Among these studies on the software power analysis, model-based analysis technique is one of major interests because it can be able to analyze the power consumption before the development of source codes, then the analysis result can be used in the development of the software system, This paper suggests a model-based power analysis technique using UML state machine diagram. Our proposed technique estimates the power consumption by the simulation of Perti-net which is transformed from the state machine diagram.

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.65-71
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• 2015

In this paper, we present binocular augmented reality system with smartphones. With improvements of performance and resolution of recent smartphones, various virtual reality devices using smartphones and applications are appearing in the market. But the augmented reality system with smartphones are not that popular because of the lack of required technologies. In our work, we discuss about 3D mapping and tracking using computer vision. Also, we provide hybrid tracking using sensors in the smartphone which can handle the computer vision failure cases. Bare hand 3D interaction method in our system will be also presented.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.127-135
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• 2014

Interactive-typed devices and contents that have been often applied in the field of entertainment and game are the technology that allows you to maximize the enjoyment and participation of users through the interaction of each. In this paper, we designed an interactive-typed smartphone app that is based on the Android platform, implemented the wearable Bluetooth device to control via a interactive interface with a vibration sensor and three-axis acceleration sensor. We tested the functionality and 3-axis motion's operability by using smartphone app, interface interactive-typed device that has been developed, prove useful as a wearable Bluetooth device that has the convenience of the user. Further, it is shown that by implementing the optimized protocol of the sensor data transfer over Bluetooth, it is possible to reduce the malfunction of the content of the smart phone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1224-1230
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• 2020

Since the spread of smart phones, interest in wearable devices has increased and diversified, and is closely related to the lives of users, and has been used as a method for providing personalized services. In this paper, we propose a method to detect the user's behavior by applying information from a 3-axis acceleration sensor and a 3-axis gyro sensor embedded in a smartphone to a convolutional neural network. Human behavior differs according to the size and range of motion, starting and ending time, including the duration of the signal data constituting the motion. Therefore, there is a performance problem for accuracy when applied to a convolutional neural network as it is. Therefore, we proposed a Time-Division Feature Fusion Convolutional Neural Network (TDFFCNN) that learns the characteristics of the sensor data segmented over time. The proposed method outperformed other classifiers such as SVM, IBk, convolutional neural network, and long-term memory circulatory neural network.