• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.5-23
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• 2011

One inevitable problem in Ad Hoc networks is the limited battery capacity, which explains why portable devices might shut down suddenly when the power of hardware is depleted. Hence, how to decrease the power consumption is an important issue in ad hoc networks. With the development of wireless technology, mobile devices can transmit voices, surf the Internet, download entertaining stuffs, and even support some P2P applications, like sharing real-time streaming. In order to keep the quality stable, the transmission must be continuous and it is thus necessary to select some managers to coordinate all nodes in a P2P community. In addition to assigning jobs to the staffs (children) when needed, these managers (ancestors) are able to reappoint jobs in advance when employees retire. This paper proposed a mechanism called Cluster-based Power Management (CPM) to stabilize the transmissions and increase Time to Live (TTL) of mobile hosts. In our new proposed method, we establish the clusters according to every node's joining order and capability, and adjust their sleep time dynamically through three different mathematical models. Our simulation results reveal that this proposed scheme not only reduces the power consumption efficiently, but also increases the total TTLs evidently.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.255-259
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• 2009

In this paper, we present AGE(Automatic Grid Environments), which is a middleware system in which Grid resources can automatically participate in a Grid environment. While other existing systems need the configuration of each Grid node to deploy a Grid environment, AGE offers automatic installation and execution of necessary middleware for participating in a Grid environment. And Grid applications in AGE do not need to be pre-installed and pre-configured. When an application is to be executed in participating Grid nodes, this system can download, install, and execute the application automatically. Therefore, AGE provides users with convenience such as deploying a Grid environment, executing the application, and releasing nodes or resources from the Grid environment automatically.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.248-251
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• 2010

Smart Phones from a PC using the Internet using a multimedia data service provides a scalable and user convenience is provided in the form of an application. Wired and wireless communications, especially with the reduction of royalty free WiFi or the Internet to download the application program on the PC you're using on the Smart Phone. In this paper, the location API in Android-based Smart Phone, using GPS coordinates identified in the latitude and longitude coordinates can be transferred to the server, Android Smart Phone to know the possibility of retracing the location. You are smart trace back information from the user application program design, development, and real-time GPS location signals combined backtrack to read the GPS location in Google Earth application is to study the trace back.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.195-203
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• 2019

Mobile applications stores such as Google Play Store and Apple App Store, are widely used to distribute a variety of applications including finance, shopping, and entertainment. Recently, however, vulnerabilities of the mobile applications are likely to violate users' privacy such as personal information leakage. In this paper, we classify mobile applications that can be download from mobile stores, and analyze the personal information that could be leaked when users are using the mobile applications. As a result of analysis, we found that personal information are leaked in some widely used mobile applications in practice. On the basis of our experiment results, we propose some mitigations to enhance security of the mobile applications and prevent leakage of personal information.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.1-8
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• 2019

Coronaviruses are known respiratory pathogens. In the past, most human coronaviruses were thought to cause mild symptoms such as cold. However recently, as seen in the Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS), infectious diseases with severe pulmonary disease and respiratory symptoms are caused by coronaviruses, making research on coronaviruses become important. Considering previous studies, we constructed 'HCoV-IMDB (Human Corona Virus Immune Database)' to systematically provide genetic information on human coronavirus and host immune information, which can be used to analyze the interaction between human coronavirus and host immune proteins. The 'HCoV-IMDB' constructed in the study can be used to search for genetic information on human coronavirus and host immune protein and to download data. A BLAST search specific to the human coronavirus, one of the database functions, can be used to infer genetic information and evolutionary relationship about the query sequence.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3583-3598
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• 2019

In order to improve the reliability and repair efficiency of distributed storage systems, minimum bandwidth regenerating (MBR) codes based on cyclic variable fractional repetition (VFR) codes are constructed in this thesis, which can repair failed nodes accurately. Specifically, in order to consider the imbalance of data accessed by the users, cyclic VFR codes are constructed according to that data with different heat degrees are copied in different repetition degrees. Moreover, we divide the storage nodes into groups, and construct MBR codes based on cyclic VFR codes to improve the file download speed. Performance analysis and simulation results show that, the repair locality of a single node failure is always 2 when MBR codes based on cyclic VFR codes are adopted in distributed storage systems, which is obviously superior to the traditional MBR codes. Compared with RS codes and simple regenerating codes, the proposed MBR codes based on cyclic VFR codes have lower repair locality, repair complexity and bandwidth overhead, as well as higher repair efficiency. Moreover, relative to FR codes, the MBR codes based on cyclic VFR codes can be applicable to more storage systems.

• Journal of Information Technology Applications and Management
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• v.26 no.1
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• pp.95-102
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• 2019

Public transportation systems play key roles in supporting dynamic activities and interaction between urban places. Especially, high efficient public transportation systems are required in order to support large traffic demands in urban areas. In this paper, we define a new metric, structural activation level (SAL), to replace the conventional transportation share ratio (TSR) measuring efficiency of public transportation systems. First of all, we access the Korea Transport Database (KTDB) and download origin-destination data by transport types to construct traffic networks with respect to transport types for each city. Then, we calculate the QAP (Quadratic Assignment Procedure) correlation between each traffic network and the total traffic network for each city to investigate SAL by comparing cities one another. The results of our investigation reveal inconsistency between TSR and SAL. In Daegu, TSR of public transportation systems is relatively low while SAL is high. In Deajeon, however, SAL is low while TSR is high. Therefore, we suggest to take into consideration SAL as well as TSR in order to investigate the degree of activation of public transportation.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.107-115
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• 2021

This paper presents a smartphone application for the clinical practice education conducted in hospitals, with an aim to evaluate its effectiveness. A nonequivalent control group posttest design was used, which included a total of 100 nursing of school students who conducted their clinical practice. They were divided into one control and one experimental group (50 students each). The control group was directly trained in the clinical practice orientation, and the experimental group was a group who self-learned the clinical practice orientation using a smartphone application. Research data were collected between March 5 and April 27, 2019. They were analyzed with descriptive statistics and independent t-test, using the SPSS Statistics Version 24. The smartphone application customized for the clinical practice education was implemented through the following four phases: analysis, design, development, and evaluation. The developed application was registered in Google Play (for Android apps) and Apple Store, and related information was provided, making it available for download. The study showed that the satisfaction with and self-confidence in learning differed significantly between the groups. However, technology acceptance and knowledge acquired through practice showed no statistically significant difference. The research results serve as basic data for applying smartphone applications as an educational method that can replace traditional modes of education, serving as a significant indicator of the education delivery method diversification.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.4
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• pp.15-27
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• 2002

The purpose of this paper is to present both the specification of delta-CRL and the polices for delta CRL in order to solve the problem involved in issuing and maintaining the certificate revocation lists for the mobile communication network. If the user request to revoke the certificate issued by certification authority, the certification should be revoked and listed up in the certificate revocation list. In general, the certificate revocation list is issued regularly. Therefore PKI application should download the CRL and prove the validity of CRL. The traffic size of the exchanged traffic should be reduced for the mobile communication environment. The result if this paper can be used for the mobile communication various environments to reduce the size of CRL.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4889-4908
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• 2020

With the advances in Information Technology (IT), users can download or stream copyrighted works, such as videos, music, and webtoons, at their convenience. Thus, the frequency of use of copyrighted works has increased. Consequently, the number of unauthorized copies and sharing of copyrighted works has also increased. Monitoring is being conducted on sites suspected of conducting copyright infringement activities to reduce copyright holders' damage due to unauthorized sharing of copyrighted works. However, suspected copyright infringement sites respond by changing their domains or blocking access requests. Although research has been conducted for improving the effectiveness of suspected copyright infringement site detection by defining suspected copyright infringement sites' response techniques as a lifecycle step, there is a paucity of studies on automation techniques for lifecycle detection. This has reduced the accuracy of lifecycle step detection on suspected copyright infringement sites, which change domains and lifecycle steps in a short period of time. Thus, in this paper, an automated detection technique for suspected copyright infringement sites is proposed for efficient detection and response to suspected copyright infringement sites. Using our proposed technique, the response to each lifecycle step can be effectively conducted by automatically detecting the lifecycle step.