• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.4
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• pp.743-755
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• 2013

In recent years, the malicious apps with malicious code in normal apps are increasingly redistributed in Android market, which may incur various problems such as the leakage of authentication information and transaction information and fraudulent transactions when banking apps to process the financial transactions are exposed to such attacks. Thus the financial authorities established the laws and regulations as an countermeasures against those problems and domestic banks provide the integrity verification functions in their banking apps, yet its reliability has not been verified because the studies of the safety of the corresponding functions have seldom been conducted. Thus this study suggests the vulnerabilities of the integrity verification functions of banking apps by using Android reverse engineering analysis techniques. In case the suggested vulnerabilities are exploited, the integrity verification functions of banking apps are likely to be bypassed, which will facilitate malicious code inserting attacks through repackaging and its risk is very high as proved in a test of this study. Furthermore this study suggests the specific solutions to those vulnerabilities, which will contribute to improving the security level of smartphone financial transaction environment against the application forgery attacks.

• The Journal of Society for e-Business Studies
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• v.22 no.1
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• pp.89-106
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• 2017

In advanced mobile devices environment, the market share of mobile application has been increased. Among various mobile services, Location-based Service (LBS) is an important feature to increase user motivation related to purchase intention on mobile. However, individual privacy has also increased as an important problem for invasion of privacy and information leakage while too many LBS based applications (App) rapidly launched in the App market. In this study, we focused on perceived values of LBS App users who use Apps related to recommending best restaurants in China and South Korea. The purpose of this study is to identify important factors for perceived value when users provide personal information for LBS service provider. The result of this study is follows: perceived value can increase while LBS customers can more control self-information and information useability. Also information ability of users affected perceived values for LBS Apps. Also users' app user ability and perceived value were effects on privacy revenue. In addtion, perceived weakness of users and perceived value increased privacy threat.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.89-93
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• 2006

We investigate a method to improve the extinction ratio of directional couplers by controlling the angle of approach to their input ports and controlling the error limit for improving the extinction ratio of the directional coupler. Although relatively large angle of approach to the input port usually causes an error in calculations made by mode propagation analysis(MPA), optimally designed angle of approach not only minimizes errors in MPA calculations but also can improve extinction ratio by precision control of coupling coefficients of optical modes. We show that abrupt changes in approaching angle, although not enough to cause modal leakage, give rise to field-profile overshooting, which degrades extinction ratio and other properties of the directional coupler. Using Beam Propagation Method (BPM) we calculate two types of input structures, linear and curved, for optimization of extinction ratio.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.2
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• pp.104-110
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• 2019

In this paper, a complementary metal oxide semiconductor(CMOS) power amplifier(PA) integrated circuit operating in the 900 MHz band for long-term evolution(LTE) communication systems is presented. The output matching network based on a transformer was implemented on a printed circuit board for low loss. Simultaneously, to achieve high efficiency of the PA, the second harmonic impedances are controlled. The CMOS PA was fabricated using a $0.18{\mu}m$ CMOS process and measured using an LTE uplink signal with a bandwidth of 10 MHz and peak to average power ratio of 7.2 dB for verification. The implemented CMOS PA module exhibits a power gain of 24.4 dB, power-added efficiency of 34.2%, and an adjacent channel leakage ratio of -30.1 dBc at an average output power level of 24.3 dBm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.539-545
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• 2014

Contact resistivity between silver electrodes and the emitter layer of a silicon solar cell wafer has been measured using either the circular transmission line method or the linear transmission line method. The circular transmission line method has an advantage over the linear transmission line method, in that it does not require an additional process for mesa etching to eliminate the leakage current. In contrast, the linear transmission line method has the advantage that its specimen can be acquired directly from a silicon solar cell. In this study, measured resistance data for the calculation of contact resistivity is compared for these two methods, and the mechanism by which the linear transmission line method can more realistically reflect the impact of the width and thickness of a silver electrode on contact resistivity is investigated.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.407-415
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• 2013

Recently, Interest variety of IT services and computing resources are increasing. As a result, the interest in the security of cloud environments is also increasing. Cloud environment is stored that to provide services to a large amount of IT resources on the Cloud. Therefore, Cloud is integrity of the stored data and resources that such as data leakage, forgery, etc. security incidents that the ability to quickly process is required. However, the existing developed various solutions or studies without considering their cloud environment for development and research to graft in a cloud environment because it has been difficult. Therefore, we proposed wire-wireless integrated Security management Model in cloud environment.

• Journal of the Korean Data and Information Science Society
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• v.23 no.5
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• pp.961-970
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• 2012

To evaluate companies that participated in the defense R&D project, 27 variables are chosen through literature survey, feature analysis of defense R&D and interviews with military experts. 17 variables are selected after factor analysis which is applied to reduce the number of variables and to detect structure in the relationships among variables, that is to classify variables using Likert-type scales. And then 17 variables are prioritized by AHP (analytic hierarchy process) method. It is shown that communication skill & cooperation strategy, level of technology, possession of needs technology have high priorities. However, protection plan of technology leakage, expertise of subcontractors, software development plan have low priorities.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.753-761
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• 2017

Recently, malicious code infiltration and leakage of confidential documents using external USB medium are frequently occurring in each field. We investigate the media to investigate incidents using external USB media, but there are many difficulties in that they can be lost or damaged. Ultimately, in order to investigate cases of external USB media, it is necessary to conduct a direct analysis of the external USB media as well as the system to which the media is connected. This paper describes an analysis of the artifacts of Windows systems to which external USB media is connected, and how to check the job history on the media. Therefore, it is expected that the system can be used to analyze the job history of the USB medium even if the external USB medium is not secured.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.61-68
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• 2015

Recently, with increasing use of smartphones, the security threats also have increased rapidly. Especially, the compromised smartphone is very dangerous because it could be exploited in a DDOS attacks such as cyberterrorism as well as in the leakage of personal information. However, most bot detection mechanisms are still unsuitable for smartphone with its lower computing capability and limited battery capacity because they incur additional computational overheads or require pre-defined signatures. In this paper, we present an efficient bot detection mechanism in smartphones. Our mechanism detects effectively bots in outgoing traffic by using a correlation between user events and network traffic. We have implemented its prototype in Android smartphone and measured its performance. The evaluation results show that our mechanism provides low overhead to detect bots in smartphones.

• KIISE Transactions on Computing Practices
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• v.22 no.7
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• pp.332-337
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• 2016

System administrator or security managers need to collect logs of computing device (desktop or server), which are used for the purpose of cause-analysis of security incident and discover if damage to system was either caused by hacking or computer virus. Furthermore, appropriate log maintenance helps preventing security breech incidents through identification of vulnerability. In addition, it can be utilized for prevention of data leakage through the insider. In the paper, we present log collection system developed using open source supported by commands and basic methods of Windows. Furthermore, we aim to collect log information to enable search and analysis from diverse perspectives and to propose a way to integrate with open source-based search engine system.