• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.51-57
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• 2012

The warming up of the recent competition in the smart phone industry followed by rapid increase of open platforms and app stores have led the mobile terminals to adopt the general purpose operating system. The mobile device utilizing this OS is vulnerable to mobile malignant code which is highly transferable. As a result, the scale of mobile attack and harm increase. However, compared to the malicious code and virus which keep increasing, the elements for security to prevent are insufficient. Therefore, this paper describe about the Context Aware Service that eliminates the potentially risky elements on the smart phone service, which could threaten the usability of the service including invasion of personal information. The proposed system prevents from disclosure of personal information by giving the procedure of information, and realizes the service that is able to change the sequence of identifying the users' information to prepare for emergency.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.2
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• pp.145-150
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• 2013

A film colored overlay has been used as an assistive device for dyslexics, Recently, several virtual colored overlays which can be used in computer were developed. But mobile virtual overlay has not been developed yet. In this paper, I implemented a mobile overlay application which is based android operating system and displays a colored overlay of screen all the time while user can freely interact with rest of apps in normal manner by using root window and service. A method is presented to determine the source color of a virtual overlays by estimating alpha value of alpha blending algorithm through measurement of the chromaticity and transmissivity of film overlays and I implemented all colors which are presented by using Intuitive Overlays. Test results of the developed virtual overlay show that all colors of the overlays are almost identical to the colors of Intuitive Overlay by using the chroma meter CS-200A.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.1-9
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• 2022

To provide real-time traffic conditions, crowd sourcing based traffic information services in which users directly report and share traffic conditions are being developed. However, the existing traffic information service provides limited traffic conditions because it only shares information reported by specific service participants. In this paper, we design and develop a crowd sourcing based traffic information service that provides real-time traffic conditions by collecting direct reports from users and public traffic conditions. The proposed service allows users to directly report traffic conditions by voice and text, and collects and integrates traffic conditions published by external organizations. The collected traffic conditions are provided in real time through a push service, and new traffic conditions are transmitted when the user's location changes. The proposed service can report traffic conditions and share real-time traffic conditions through an Android app.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.177-182
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• 2023

When determining a meeting place, it is always a cumbersome problem to select an appropriate store with a short travel time for all participants. In this paper, to solve this problem, we propose an algorithm that recommends the best place and store based on the subway station and develop the system. This system provides a web-based store information registration function that allows self-employed people to register and promote their store, and provides an app-based function to recommend a meeting place to participants. The proposed algorithm reduces the travel time of all participants based on the subway map and improves fairness by using the standard deviation of the required time. In addition, this system presents a new way for self-employed people who have recently relied only on publicity through delivery apps.

• Journal of the Korea Convergence Society
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• v.4 no.2
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• pp.29-33
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• 2013

From one elementary school of last 2005 Pusan was started "the school police" system is being applied the effect in the elementary school of the human nature receiving entire country. But "with school police system " have a limit about manpower that is insufficient. So we try to make "Baumter-Gikimy " that is extended scollo police in seoul. Despite being like that at 2010 and 2011 cannot forget the elementary student suicide events which are shocking or sexual assault events occur from the campus.From elementary school 4 grade the students between junior high school 1 grade crime occurrence ratio are highest. These people the group leaving out mainly, suicide, with group violence and sexual assault problem gets up same problems. In order to solve like this problems stands the countermeasure of the dimension which is national certainly is necessary. But so far only the damage student and the parents have an interest in about like this problems and they hurt. We the smart phone of Android bases it will be able to solve like this problem points [ayp] from under planning and development boil the elementary student safe helper it will can use. When it uses the elementary student safe helper system which we propose before the accident occurs, it will grasp the state information of the student and it will be able to prevent an accident in advance. We will try to more efficient safe guard to elementary school student by real-time monitoring skill soon.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.827-839
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• 2012

A cell phone is very close to the user and therefore should be considered in digital forensic investigation. Recently, the proportion of smartphone owners is increasing dramatically. Unlike the feature phone, users can utilize various mobile application in smartphone because it has high-performance operating system (e.g., Android, iOS). As acquisition and analysis of user data in smartphone are more important in digital forensic purposes, smartphone forensics has been studied actively. There are two way to do smartphone forensics. The first way is to extract user's data using the backup and debugging function of smartphones. The second way is to get root permission, and acquire the image of flash memory. And then, it is possible to reconstruct the filesystem, such as YAFFS, EXT, RFS, HFS+ and analyze it. However, this methods are not suitable to recovery and analyze deleted data from smartphones. This paper introduces analysis techniques for fragmented flash memory pages in smartphones. Especially, this paper demonstrates analysis techniques on the image that reconstruction of filesystem is impossible because the spare area of flash memory pages does not exist and the pages in unallocated area of filesystem.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1135-1144
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• 2018

An electric wheelchair used to be utilized as a piece of equipment for the disabled and the elderly in the past, but the recent changes to its functions and forms have made it available across various fields and purposes. In this paper, we propose a continuous track type of electric wheelchair prototype to be used in various fields and environments and a monitoring system to control it. A frame stress design was applied to improve its stability during driving compared with the previous wheelchairs. In addition, we provide a convenience for free and easy operation of them using the App. based on android. A monitoring system based on C# was also added to control a large number of electric wheelchairs. As a result of the implementation and performance evaluation, the von Mises stress value was measured 4.401% within the normal range through five times of stress interpretations, and its accuracy of communication for system manipulation was recorded about 98.75%, which means that it has been proven to be safer than the previous wheelchairs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.4
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• pp.739-751
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• 2014

We are using our smartphone for our business as well as ours lives. Thus, user's privacy data and a company secret are stored at smartphone. By the way, the saved data on smartphone database can be exposed to a malicous attacker when a malicous app is installed in the smartphone or a user lose his/her smartphone because all data are stored as form of plaintext in the database. To prevent this disclosure of personal information, we need a database encryption method. However, if a database is encrypted, it causes of declining the performance. For example, when we search specific data in condition with encrypted database, we should decrypt all data stored in the database or search sequentially the data we want with accompanying overhead[1]. In this paper, we propose an efficient and searchable encryption method using variable length bloom filter under limited resource circumstances(e.g., a smartphone). We compare with existing searchable symmetric encryption. Also, we implemented the proposed method in android smartphone and evaluated the performance the proposed method. As a result through the implementation, We can confirm that our method has over a 50% improvement in the search speed compared to the simple search method about encrypted database and has over a 70% space saving compared to the method of fixed length bloom filter with the same false positive rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.396-402
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• 2016

Recently, as the performance of smart phones has advanced and their distribution has increased, various functions in existing devices are accumulated. In particular, functions in smart devices have matured through improvement of diverse sensors. Various applications with the development of smart phones get fleshed out. As a result, services from applications promoting physical activity in users have gotten attention from the public. However, these services are about diet alone, and because these have no exercise motion recognition capability to detect movement in the correct position, the user has difficulty obtaining the benefits of exercise. In this paper, we develop exercise motion-recognition software that can sense the user's motion using a sensor built into a smart phone. In addition, we implement a system to offer exercise with friends who are connected via web server. The exercise motion recognition utilizes a Kalman filter algorithm to correct the user's motion data, and compared to data that exist in sampling, determines whether the user moves in the correct position by using a DTW algorithm.