• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.227-229
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• 2012

한국해양연구원에서 개발하고 있는 해저보행로봇 CR200은 6개의 다리를 이용하여 해저면에서 보행으로 이동하며 정밀 해저탐사 및 작업을 수행할 수 있는 로봇이다. 운용자는 선상제어실에서 유선으로 연결된 CR200을 원격으로 모니터링하거나 제어한다. 특히 안정적인 보행을 위해서는 100Hz의 주기로 CR200의 상태 정보가 선상제어실로 전송되고, 선상제어실에서는 전송된 정보를 기반으로 제어 명령을 산출하여 CR200으로 전송해야 한다. 이러한 주기적인 실시간 제어를 위해서는 일반적으로 실시간 운영체제를 사용하지만, 본 논문에서는 실시간 운영체제를 사용하지 않고 시스템 시간 기반의 백그라운드 프로세스로 동작하는 소프트웨어 타이머를 사용하여 실시간 제어를 하는 방법을 제안하고, 성능 평가 결과를 제시한다. 제안한 방법의 실시간 속성을 검증하기 위하여, 현재 설계에서 운영체제로 고려하고 있는 우분투 10.04와 윈도우즈 7을 CR200에 탑재되는 Advantech 사의 PCM-3362 보드에 설치하여 소프트웨어 타이머의 성능을 10ms부터 100ms까지 각각 실험하였다. 실험결과에 따르면, 두 운영체제에서 모두 누락이 없이 타이머 동작이 수행되었으며, 10ms 간격으로 타이머를 동작하였을 때에 우분투에서는 평균 오차가 $41{\mu}s$이었고 윈도우즈 7에서는 7.7ms였다. 윈도우즈 7에서의 오차는 100Hz 제어 주기에 사용하기에 적합하지 않지만, 우분투에서의 오차는 제어 주기 간격의 0.41%에 불과하기 때문에 해저보행로봇의 실시간 제어에 영향을 주지 않는 오차이다. 따라서 CR200의 임베디드 컴퓨터와 선상제어실의 원격제어 컴퓨터는 우분투 운영체제 상에서 소프트웨어 타이머를 이용하여 상호 연동되도록 구현할 예정이다.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.7
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• pp.149-156
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• 2020

All operating systems have privileged administrator accounts for efficient management. Dangerous or sensitive tasks or resources should be banned from normal users and should only be accessible by administrators. One example of this privilege is to reset a user's password when the user loses his/her password. In this paper, the privileges of the sudoer group, the administrator group of Linux Ubuntu, and the management system of the sudoer group were analyzed. We show the danger that a sudoer can use the privilege to change the password of other users, including other sudoers, and modify the log, and suggest a countermeasure to prevent the manipulation of shadow files as a solution to this. In addition, the proposed method was implemented and the possibility of practical use was confirmed with excellent performance.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.335-338
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• 2020

주로 맵 빌딩 테스트는 불안정한 환경이 아닌 안정된 환경을 조성한 후에 이루어진다. 본 논문에서는 인위적인 안정된 환경이 아닌 불안정한 환경에서 맵 빌딩을 테스트한다. 맵 빌딩 테스트를 위하여 터틀봇3 버거를 사용한다. 터틀봇3의 라이더 센서를 이용하여 맵 빌딩을 진행한다. 터틀봇3는 라즈베리파이로 제어되며 맵 빌딩과 터틀봇3 제어를 위해서는 ROS를 사용한다. 터틀봇3는 우분투와 ROS가 설치된 컴퓨터와 네트워크 통신을 하며 맵 빌딩을 한다. 불안정한 환경에서 맵빌딩이 동작 및 오동작하는 모습을 확인하였으며, 향후 이를 보완하기 위한 방향을 제시한다.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.304-309
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• 2017

Programmers use multiple languages to reuse legacy code best suited to their problems. However, it is quite challenging to develop error-free multilingual programs because new types of bugs occur since misunderstanding about language interfaces such as Java Native Interface (JNI) and Python/C. There is a considerable amount of research to overcome multilingual program bugs and errors but these researches have less consideration about substantiality of programming languages, language interfaces, and bugs to evaluate their analyses and tools. In this paper, we have identified and establish substantiality of multilingual programming research with empirical study about diversity and interoperability of programming languages in Ubuntu software ecosystem based on real-world statistical data.

• Journal of Digital Contents Society
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• v.17 no.2
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• pp.97-103
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• 2016

This work introduces techniques experienced for the electrocardiogram(ECG) visual analysis, able to characterize the major parameters and events with clinical relevance for heart failure management and cardiovascular risk assessment. In particular, it includes approaches for ECG data visual processing such as the variable charts, graphs base on the complex MIT-BIH ECG database. Through the experienced this works of ECG database visualization, so many researcher more easily access the complex ECG database and can intuitionally understand the meanings via a variable ECG visualized data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.623-628
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• 2016

Because the log information provides some critical clues for solving the problem of illegal system access, it is very important for a system administrator to gather and analyze the log data. In a Linux system, the syslog utility has been used to gather various kinds of log data. Unfortunately, there is a limitation that a system administrator should rely on the services only provided by the syslog utility. To overcome this limitation, this paper suggests a syslog agent that allows the system administrator to gather log information for file access that is not serviced by syslog utility. The basic concept of the suggested syslog agent is that after creating a FUSE, it stores the accessed information of the files under the directory on which FUSE has been mounted into the log file via syslog utility. To review its functional validity, a FUSE file system was implemented on Linux (Ubunt 14.04), and the log information of a file access was collected and confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.8-14
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• 2016

When Open Source Projects are processed by multiple developers, the Version Control Systems, which control the different versions of the same file being used, is a very useful tool. On the other hand, because most of conventional VCS(SVN, Git, etc.) mainly control the history of the modifications of the source codes or documents, there is an inconvenience that each developer should modify the development environment whenever the development environment is modified. To overcome this inconvenience, this paper suggests a scheme of VC for OSP. The basic concept of the suggested scheme is that an image, including the development environment and controls, is created as a new version using the Docker, virtualization tool of the container method. To review the functional appropriateness of the suggested scheme, after establishing the Docker on the hosts that use the different OS( Ubuntu12.0.4, CentOS7), this study tested a VC that could control the different versions including the history of modifications of the development environment and evaluated them by a comparison with the conventional VCS. The results show that the suggested scheme is a convenient scheme of VC for the OSP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.868-871
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• 2016

Recently, Unmanned vehicle and Wearable Technology using iot research is being carried out. The unmanned vehicle is the result of it technology. Robots, autonomous navigation vehicle and obstacle avoidance, data communications, power, and image processing, technology integration of a unmanned vehicle or an unmanned robot. The final goal of the unmanned vehicle manual not autonomous by destination safely and quickly reaching. This paper managed to cover One of the key skills of unmanned vehicle is to image processing. Currently battery technology of unmanned vehicle can drive for up to 1 hours. Therefore, we use the Raspberry Pi 3 to reduce power consumption to a minimum. Using the Raspberry Pi 3 and to develop an image recognition system. The goal is to propose a system that recognizes all the objects in the image received from the camera.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1231-1236
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• 2014

Recently, diffusion and proliferation of mobile devices increases, per person n opens for the mobile device era. Mobile devices and OS types of continuously growing trend. More than 80% of market share with Google's Android and Apple's iOS as well as Samsung and Intel is developing TIZEN, Linux and Mobile was the UBUNTU which UBUNTU for Phone, UBUNTU touch, Mozilla 's Firefox OS, Microsoft 's windows mobile and many more OS are ahead of the launch. But different OS can share files between systems or technology is not. Bluetooth or WIFI Direct such technologies are present but can be transferred between compatible devices low, resulting in constraints file types also exist. In this paper, is equipped with a WiFi card in an environment where the Android mobile OS party this model and method for sharing files between different research and can share the file system based on research on.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.3
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• pp.298-305
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• 2016

Various NoSQL databases are more excellent to process a large amount of big data than existing relational databases such as MySQL, PostgreSQL and Oracle. Among widely used NoSQL databases, performance of HBase, Cassandra, MongoDB and Redis was comparatively assessed. For distributed processing of a large amount of data, 12 servers were connected through switching hub and Ubuntu was installed as operating system. As for benchmark tool, YCSB was applied. Read and update ratios changed from 50% and 50%, 95% and 5% and finally, 100% and 0% and each of them was assessed as 200,000 commands developed into 1,200,000 commands for each case. Cassandra was most excellent with transaction processing per second while MongoDB was most excellent with the number of processes carried out per unit time.