• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.411-413
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• 2012

It is noticeable that the number of newly registered Android applications increases rapidly. Such a recent trend indicates the Android platform is spreading globally. The ongoing platform upgrade might be one of the main reasons of the popularity of the Android mobile platform. Android platform 4.0 or later provides WiFi-Direct APIs that allow smart devices to communicate with each other without intermediate media. In this paper, we propose design and implementation techniques for small-scale impromptu meeting applications based on WiFi-Direct. The proposed meeting application can be used in a situation when one is difficult to connect the Internet. It also provides meeting data sharing capabilities, noting functionality, real-time remote screen control, and grouping of meeting participants. Our development results have demonstrated that the Android WiFi-Direct APIs can be effectively applied to impromptu conferencing mobile applications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1641-1647
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• 2018

In this paper, we describe a portable potentiostat which is capable of cyclic voltammetry(CV) and amperometry for electrochemical dissolved oxygen sensor. In addition, this portable potentiostat can also transmit the measured data wirelessly to android devices such as smart phone, tablet, etc. through Bluetooth. The potentiostat system consists of three parts; a voltage generator circuit which is controlled by Arduino nano and 12-bit DAC(digital to analog converter) to generate necessary electric potential for operating the electrochemical sensor, an oxidation/reduction current measurement circuit, and a Bluetooth module to transmit data wirelessly to an android device. Once measurements are carried out with the android application, the measured data is transmitted to the android device via Bluetooth and displayed using the android app. in real time. In this paper, we report the measured reduction current with a fabricated dissolved oxygen sensor in both saturated-oxygen state and zero-oxygen states. The results of the developed portable potentiostat system are in good agreement with those of the commercial portable potentiostat (${\mu}stat200$, Dropsens inc.). The measured peak reduction currents using the developed potentiostat and the commercial ${\mu}stat200$ potentiostat were $-0.755{\mu}A$ and $-0.724{\mu}A$, respectively. The reduction currents measured at zero-oxygen state were $-0.005{\mu}A$ and $-0.004{\mu}A$. The discrepancy between those two systems seems very small, which implies successful development of a portable and wireless potentionstat.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.267-275
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• 2021

Smart application is developed in this paper by using an android-based platform to automatically determine the human emergency state (Lifesaver) by using different technology sensors of the mobile. In practice, this Lifesaver has many applications, and it can be easily combined with other applications as well to determine the emergency of humans. For example, if an old human falls due to some medical reasons, then this application is automatically determining the human state and then calls a person from this emergency contact list. Moreover, if the car accidentally crashes due to an accident, then the Lifesaver application is also helping to call a person who is on the emergency contact list to save human life. Therefore, the main objective of this project is to develop an application that can save human life. As a result, the proposed Lifesaver application is utilized to assist the person to get immediate attention in case of absence of help in four different situations. To develop the Lifesaver system, the GPS is also integrated to get the exact location of a human in case of emergency. Moreover, the emergency list of friends and authorities is also maintained to develop this application. To test and evaluate the Lifesaver system, the 50 different human data are collected with different age groups in the range of (40-70) and the performance of the Lifesaver application is also evaluated and compared with other state-of-the-art applications. On average, the Lifesaver system is achieved 95.5% detection accuracy and the value of 91.5 based on emergency index metric, which is outperformed compared to other applications in this domain.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.1
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• pp.169-176
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• 2016

Android platform is designed to be user-friendly, yet sometimes its convenience introduces vulnerabilities that normal users cannot justify. In this paper, after making an overview of popular open source analysis tools for android applications, we point out the dangerous use of Permission Group in current Google Policy, and suggest a technique to mitigate the risks of privilege escalation that attackers are taking advantage of. By conducting the investigation of 21,064 malware samples, we conclude that the proposed technique is considered effective in detecting insecure application update, as well as giving users the heads-up in security awareness.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.2
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• pp.213-221
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• 2013

According to the rapid growth of the number of SNS(Social Networking Service) applications based on Android OS, the importance of its security is also raised. Especially, many applications using KaKaoTalk platform has been released in these days, and these are top ranked in the relative markets. However, security issues on SNS applications have not been resolved clearly. Therefore, it is crucial to provide means to cope with the security threats posed by code-segment modification in the development stage of Android OS based SNS applications. In this paper, we analyze the security threats by modifying SNS application code segments and suggest effective security techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.7-15
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• 2010

Recently, there are many home network applications using the convergence between mobile platforms and home network system. As smart phones which are called small PC in the hand becoming popular, the development of home network application beyond the one of cellular phones is required. Android mobile platform of Google includes OS, middleware and primary applications. Also, in addition to smart phones, it can be mounted on various devices such as set-top box and household appliances. In this paper, home network services on smart phones of Android platform are designed and implemented. The services provide real-time monitoring information (temperature, humidity, real-time video) of rooms and appliance control in a house.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.738-745
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• 2014

Recently, mobile users continuously increase, and mobile applications also increase As mobile applications increase, the mobile users used to store sensitive and private information such as Bank information, location information, ID, password on their mobile devices. Therefore, recent malicious application targeted to mobile device instead of PC environment is increasing. In particular, since the Android is an open platform and includes security vulnerabilities, attackers prefer this environment. This paper analyzes the performance of malware detection system applying linear SVM machine learning classifier to detect Android malware application. This paper also performs feature selection in order to improve detection performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.549-562
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• 2017

In recent years, as the proportion of mobile banking has become bigger with daily usage of mobile banking, security threats are also increasing according to the feeling. Accordingly, the domestic banking system introduces security solution programs in the banking application and sets security check points to ensure the stability of the application in order to check whether it is always executed. This study presents a vulnerability of inactivity bypassing mobile vaccine program operation checkpoints using the intermediate language statically and dynamically analysis when decompiling the android banking applications of major banks in Korea. Also, through the results, it identifies possible attacks that can be exploited and suggest countermeasures.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1457-1465
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• 2017

With the growing of smart devices market, malicious behavior has gradually expanded its scope. Accordingly, many studies have been conducted to analyze malicious apps and automated analysis tools have been released. However these tools cause the side effects that the application protection tools such as ProGuard, DexGuard become vulnerable to analyzers or attackers. This paper suggests the protection mechanism to apply to the Android apps using security token, rather than general-purpose protection solutions that can be applied in malicious apps. The main features of this technique are that Android app is not properly loaded in the memory when the security token is abnormal or is not inserted and protected parts using the technique are not exposed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1553-1561
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• 2018

The source code for Android is open and easy to modify depending on the purpose. Recently, this charateristic has been exploited to bypass the runtime protection technique and extract the original executable code. Unfortunately, Android devices are so fragmented that it is difficult to verify the integrity of the system. To solve this problem, this paper proposes a technique to verify the integrity of the execution environment indirectly using the features of the application permission. Before executing the original executable code, it loads and executes the dummy DEX file to monitor for abnormal events and determine whether the system is intact. The proposed technique shows a performance overhead of about 2 seconds and shows that it can detect the bypassing technique that is currently disclosed.