• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.121-132
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• 2009

Default password protection used in operating systems have had many advances, but when the attacker has physical access to the server or gets root(administrator) privileges, the attacker can steal the password information(e.g. shadow file in Unix-like systems or SAM file in Windows), and using brute force and dictionary attacks can manage to obtain users' passwords. It is really difficult to obligate users to use complex passwords, so it is really common to find weak accounts to exploit. In this paper, we present a secure authentication scheme based on digital signatures and secure key storage that solves this problem, and explain the possible implementations using Trusted Platform Module(TPM). We also make a performance analysis of hardware and software TPMs inside implementations.

• Convergence Security Journal
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• v.15 no.2
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• pp.63-68
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• 2015

Current ICT(Information & Communication Technology) infrastructures (Internet and server/client communication) are struggling for a wide variety of devices, services, and business and technology evolution. Cloud computing originated simply to request and execute the desired operation from the network of clouds. It means that an IT resource that provides a service using the Internet technology. It is getting the most attention in today's IT trends. In the distributed cloud environments, management costs for the network and computing resources are solved fundamentally through the integrated management system. It can increase the cost savings to solve the traffic explosion problem of core network via a distributed Micro DC. However, traditional flooding methods may cause a lot of traffic due to transfer to all the neighbor DCs. Restricted Path Flooding algorithms have been proposed for this purpose. In large networks, there is still the disadvantage that may occur traffic. In this paper, we developed Lightweight Path Flooding algorithm to improve existing flooding algorithm using hop count restriction.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.129-136
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• 2017

3D seismic data processing methods such as full waveform inversion or reverse-time migration require 3D wave propagation modeling and heavy calculations. We compared efficiency and accuracy of a Xeon Phi coprocessor to those of a high-end server CPU using 3D frequency-domain wave propagation modeling. We adopted the OpenMP parallel programming to the time-domain finite difference algorithm by considering the characteristics of the Xeon Phi coprocessors. We applied the Fourier transform using a running-integration to obtain the frequency-domain wavefield. A numerical test on frequency-domain wavefield modeling was performed using the 3D SEG/EAGE salt velocity model. Consequently, we could obtain an accurate frequency-domain wavefield and attain a 1.44x speedup using the Xeon Phi coprocessor compared to the CPU.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.345-352
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• 2017

In this paper, we design and implement an educational robot system that can use scratch education with the function of user demanding to perform robot education in actual school site in an embedded environment. It is developed to enable physical education for sensing information processing, software design and programming practice training that is the basis of robotic system. The development environment of the system is Arduino Uno based product using Atmega 328 core, debugging environment based on Arduino Sketch, firmware development language using C language, OS using Windows, Linux, Mac OS X. The system operation process receives the control command of the server using the Bluetooth communication, and drives various sensors of the educational robot. The curriculum includes Scratch program and Bluetooth communication, which enables real-time scratch training. It also provides smartphone apps and is designed to enable education like C and Python through expansion. Teachers at the school site used the developed products and presented performance processing results satisfying the missionary needs of the missionaries.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.445-454
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• 2006

Almost of industrial measuring instruments usually are equipped only with serial communication devices. In order to connect these instruments to internet, we implement an embedded translator. This device has the hardware components composed of one WAN port, two LAN ports, and two UARTs, and functions as a communication translator between serial and internet communication. it also provides web-based monitoring function that is absent from existing serial-to-ethernet converter. The hardware is implemented using the KS8695 network processor which s an ARM922T as processor core. We have installed the boa web server and utilized the CGI function for internet-based remote control, added the IP sharing function which allows the network with private IP addresses to access the internet, and developed a serial-to-ethernet translation program. Finally, we show an application example of the developed translator that remotely monitors the solar energy production system.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.813-826
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• 2019

This paper is a study on the implementation of MAM(Media Asset Management) to utilize UHD contents as high quality broadcast material. The implementation method of this paper is to separate MAM roles with content management functions and transmission workflow functions from workflow, metadata and system interface related work, which are divided into core MAM and MAM-Ex structure. Through the method proposed in this paper, we improved the content management method by applying the page menu method to the material metadata modification and applying the template method to the material structure API. In addition, the storage of UHD material and the configuration of the component server are pooled without any distinction of channels, thereby enhancing the security of UHD transmission assets by minimizing the movement of contents together with broadcasting material protection.

• KNOM Review
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• v.23 no.1
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• pp.43-50
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• 2020

As General Purpose Graphics Processing Unit (GPGPU) recently plays an essential role in high-performance computing, several cloud service providers offer GPU service. Most cluster orchestration platforms in a cloud environment using containers allocate the integer number of GPU to jobs and do not allow a node shared with other jobs. In this case, resource utilization of a GPU node might be low if a job does not intensively require either many cores or large size of memory in GPU. GPU virtualization brings opportunities to realize kernel concurrency and share resources. However, performance may vary depending on characteristics of applications running concurrently and interference among them due to resource contention on a node. This paper proposes GPU container co-execution framework with multiple server creation and execution based on Kubernetes, container orchestration platform for measuring interference which may be occurred by sharing GPU resources. Performance changes according to scheduling policies were investigated by executing several jobs on GPU. The result shows that optimal scheduling is not possible only considering GPU memory and computing resource usage. Interference caused by co-execution among applications is measured using the framework.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.368-374
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• 2020

Journaling file systems (JFS) manage changes of file systems not yet committed in a data structure known as a journal to restore the file system in the event of an unexpected failure. Extra write operations required for journaling negatively affect the performance of JFS. The high-performance and byte-addressable non-volatile memory (NVM) was expected to easily mitigate these performance problems by providing NVM space as journal storage. However, even with such non-volatile memory technologies, performance problems still arise due to scalability problems inherent in processing transactions of JFS. To solve this problem, we proposes a technique for processing file system transactions for scalable performance. To this end, lock-free data structures are used and multiple I/O requests are allowed to simultaneously be processed on high-performance storage devices with multiple I/O channels. We evaluate the file system with the proposed technique by comparing the original ext4 file system and the recent proposed NVM-based journaling file system on a multi-core server, and experimental results show that our file system has better performance (up-to 2.9/2.3 times) than the original ext4 file system and the recent NVM-based journaling file system, respectively.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.19-25
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• 2010

We developed a RFID terminal to voice guide the blind who have difficulties in reaching out to the pharmaceutical information. In this work, we used RFID technology to instruct the pharmaceutical information to the blind. The voice guidance reader was made to read the RFID tag attached to the drugs and announced the pharmaceutical information matching to the tag specific ID. We had the reader to obtain the pharmaceutical information from the ezDrug site operated by Korea Food & Drug Association. The voice guidance reader was fabricated as necklace type for the easy carry, and we added mp3 player as dual uses. ARM series Cortex M3 chip was used for the reader's core chip and low power MFRC523 chipset of NXP was used to construct RFID circuit. MFRC523 chip uses low power to meet the mobile application. We used VS1003B MP3 Decoder IC to make the voice generation circuit and CC2500 chipset for the wireless communication to the pharmaceutical information server. We also developed the system that can support ISO 14443A type and ISO 14443B type so that the system can be used to extend to various RFID protocols. Utilization of this system can conveniently convey the pharmaceutical information to the blind and reduce the drug abuse.