• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.57-65
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• 2017

The electronic components in mobile device are composed of electronic chips and various other materials. These components become extremely thin and the constituent materials have different coefficient of thermal expansion, so that considerable warpages occurs easily due to temperature change or external load. Shadow $moir{\acute{e}}$ is non-contact, whole field technique for measuring out-of-plane displacement, but the measurement sensitivity is not less than $50{\mu}m/fringe$, which is not suitable for measuring the warpage of the electronic components. In this paper, we implemented a measurement method with enhanced sensitivity of $25{\mu}m/fringe$ by investigating and optimizing various experimental conditions of the shadow $moir{\acute{e}}$. In addition, four $moir{\acute{e}}$ fringe patterns recorded by the phase shift are processes to obtain a $moir{\acute{e}}$ fringe patterns with a sensitivity four times higher. The measurement technique is applied to small electronic components of a smart phone for measuring warpage with a high sensitivity of $5{\mu}m/fringe$ at room temperature and at the temperature of $100^{\circ}C$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2423-2428
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• 2015

We have implemented a personal prescription management system which enables resource-limited mobile device to utilize the optical character recognition technique. The system enables us to automatically detect and recognize the text in the personal prescription by using a optical character recognition technique. We improved the recognition rate over a pre-processing in order to improve the character recognition rate of the original method. The examples such as a personal prescription management service, alarm service, and drug information service with mobile devices have been demonstrated by using the our system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.18-24
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• 2010

Mobile devices wide spread among users after the release of Apple's iPhone, especially in Korea. Mobile device has their own advantages in terms of weight, size, mobility and so on. But, on the contrary, mobile device has to provide more accurate and personalized information because of a small screen and a limited function of information retrieval. This paper presents a user"s preference element changeable recommender system by employing extended collaborative filtering as a technique to provide useful information in a mobile environment. Proposed system reflects user's similar groups by simultaneously considering users' information with preferences and demographic characteristics. Then we construct list of recommenders by user's choice. Finally, we show the implementation of a prototype based on iPhone.

• Convergence Security Journal
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• v.15 no.1
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• pp.3-9
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• 2015

In this paper, a detection technique of smishing using a TaintDroid is suggested. Suggesting system detects malicious acts by transmitting a URL to the TaintDroid server and installing a relevant application to a virtual device of the TaintDroid server, when a smartphone user receives a text message including the URL suspected as a smishing. Through this we want to distinguish an application that can not install because of suspicion of a smishing in an actual smartphone whether said application is malicious application or not by testing with the virtual device of said system. The detection technique of a smishing using the TaintDroid suggested in this paper is possible to detect in a new form a smishing with a text message and to identifying which application it is through analysis of results from a user.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.183-185
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• 2013

As mobile devices have developed, flash animations suitable for the existing web have solved part of the weakness caused by the image quality deterioration and the transmission capacity, but it is difficult to express 3D stereo-scopic images. Also, for the real time-randering of visual expressions for animation and the device technique for smartphone to accord with commercial demands, it is required to develop the 3D image processing technique. This paper studied on the image processing method for 3D animation capable of 3D graphic rendering with view system of android and OpenGL M3G in an embedded system device and OpenGL ES 2.0 library.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.133-142
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• 2009

Recently, with the advance of wireless internet and the frequent use of mobile devices, demand for LBS(Location Based Service) is increasing, and research is required on spatial indexes for the storage and maintenance of spatial data to provide efficient LBS in mobile device environments. In addition, the use of flash memory as an auxiliary storage device is increasing in order to store large spatial data in a mobile terminal with small storage space. However, the application of existing spatial indexes to flash-memory lowers index performance due to the frequent updates of nodes. To solve this problem, research is being conducted on flash-memory based spatial indexes, but the efficiency of such spatial indexes is lowered by low utilization of buffer and flash-memory space. Accordingly, in order to solve problems in existing flash-memory based spatial indexes, this paper proposed FR-Tree (Flash-Memory based R-Tree) that uses the node compression technique and the delayed write operation technique. The node compression technique of FR-Tree increased the utilization of flash-memory space by compressing MBR(Minimum Bounding Rectangle) of spatial data using relative coordinates and MBR size. And, the delayed write operation technique reduced the number of write operations in flash memory by storing spatial data in the buffer temporarily and reflecting them in flash memory at once instead of reflecting the insert, update and delete of spatial data in flash-memory for each operation. Especially, the utilization of buffer space was enhanced by preventing the redundant storage of the same spatial data in the buffer. Finally, we perform ed various performance evaluations and proved the superiority of FR-Tree to the existing spatial indexes.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.9
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• pp.263-272
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• 2023

Industrial Internet of Things (IIoT) is an important factor in increasing production efficiency in industrial sectors, along with data collection, exchange and analysis through large-scale connectivity. However, as traffic increases explosively due to the recent spread of IIoT, an allocation method that can efficiently process traffic is required. In this thesis, I propose a two-stage task offloading decision method to increase successful task throughput in an IIoT environment. In addition, I consider a hybrid offloading system that can offload compute-intensive tasks to a mobile edge computing server via a cellular link or to a nearby IIoT device via a Device to Device (D2D) link. The first stage is to design an incentive mechanism to prevent devices participating in task offloading from acting selfishly and giving difficulties in improving task throughput. Among the mechanism design, McAfee's mechanism is used to control the selfish behavior of the devices that process the task and to increase the overall system throughput. After that, in stage 2, I propose a multi-armed bandit (MAB)-based task offloading decision method in a non-stationary environment by considering the irregular movement of the IIoT device. Experimental results show that the proposed method can obtain better performance in terms of overall system throughput, communication failure rate and regret compared to other existing methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1364-1370
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• 2017

This paper proposes a method that automatically sets profile schedule context-based mobile phone by collecting the user's external situation based on the GPS sensor and accelerometer built into the smartphone and interacting with the data in the user's schedule to minimize the user's handset handling. However, real-time data collection in mobile phones causes energy shortage in the device due to battery consumption. In other words, a service control method is explained in a way that can efficiently handle resource consumption because accessing a measurement device such as GPS and other sensors may increase power consumption of the portable device. Therefore, effective data sharing for context awareness to reduce weekly schedules and smartphone mode has improved energy efficiency in sensing for data collection. The user can use the context more effectively by providing environmental adaptability for various situations such as the end user's local context and smartphone force control.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.123-132
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• 2014

In this paper, we study the verification techniques for OS integrity that can be more fatal than applications in case of security issues. The dissemination of smartphones is rapidly progressing and there are many similarities of smartphones and PCs in terms of security risks. Recently, in mobile network environment, there is a trend of increasing damages and now, there are active researches on a system that can comprehensively respond to this. As a way to prevent these risks, integrity checking method on operation system is being researched. As most integrity checking algorithms are classified by verification from the levels before booting the OS and at the time of passing on the control to the OS, in which, there are minor differences in the definitions of integrity checking or its methods. In this paper, we suggests the integrity verification technique of OS using a boot loader and a physically independent storing device in the mobile device.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.47-58
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• 2011

Recently, there are several technologies for protecting information in the lightweight device, One of them, the AES[1] algorithm and CRT mode, is used for numerous services(e,g, OMA DRM, VoIP, IPTV) as encryption technique for preserving confidentiality. Although it is possible that the AES algorithm CRT mode can parallel process transmitting data, IPTV Set-top Box or Mobile Device that uses these streaming service has limited computation-ability. So optimizing crypto algorithm and enhancing its efficiency for those environment have become an important issue. In this paper, we propose implementation method that can improve efficiency of the AES-CRT Mode by improving algorithm logics. Moreover, we prove the performance of our proposal on the mobile device which has limited capability.