• KIISE Transactions on Computing Practices
• /
• v.22 no.1
• /
• pp.20-25
• /
• 2016

With the advent of the era of digital big data, the Hadoop platform has become widely used in various fields. However, the Hadoop MapReduce framework suffers from problems related to the increase of the name node's main memory and map tasks for the processing of large number of small files. In addition, a method for running C++-based tasks in the MapReduce framework is required in order to conjugate GPUs supporting hardware-based data parallelism in the MapReduce framework. Therefore, in this paper, we present a face detection system that generates a sequence file for images to process big data for images in the Hadoop platform. The system also deals with tasks for GPU-based face detection in the MapReduce framework using Hadoop Pipes. We demonstrate a performance increase of around 6.8-fold as compared to a single CPU process.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.1C
• /
• pp.54-62
• /
• 2012

A Wi-Fi mesh network providing multi-hop wireless connections based on IEEE 802.11 PHY/MAC technology has recently received a significant attention as a network infrastructure that interconnects RFID systems and wireless sensor networks (WSNs). However, the current IEEE 802.11 contention-based MAC protocol cannot fully utilize the network capacity due to eithor frame collisions or unused network resources. In this paper, we propose a novel multi-channel scheduling MAC (MCS-MAC) protocol for Wi-Fi mesh networks. Under the secondary interference model of Wi-Fi mesh networks, the MCS-MAC protocol can maximize the network throughput via activation of collision-free links that has a maximal link weight. Through the simulations, we show that the throughput of the MCS-MAC protocol is at least three times higher than that of existing MAC protocols in Wi-Fi mesh networks.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.6
• /
• pp.503-511
• /
• 2013

This paper presents a speech enhancement method using non-negative matrix factorization. In training phase, we can obtain each basis matrix from speech and specific noise database. After training phase, the noisy signal is separated from the speech and noise estimate using basis matrix in enhancement phase. In order to improve the performance, we model the change of encoding matrix from training phase to enhancement phase using independent Gaussian distribution models, and then use the constraint of the objective function almost same as that of the above Gaussian models. Also, we perform a smoothing operation to the encoding matrix by taking into account previous value. Last, we apply the Log-Spectral Amplitude type algorithm as gain function.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.3C
• /
• pp.105-113
• /
• 2009

Pressuremeter test estimates deformational properties of soil from the relationship between applied pressure and the displacement of cavity wall, and the results reflect the in-situ stress condition and the structure of soil particles. This study suggests the overall process of test and analysis for the evaluation of nonlinear degradation characteristics of shear moduli, based on the reloading curve of pressuremeter test. The method estimates the maximum shear modulus, taking into account the difference between the stress states around the probe in reloading and that of the in-situ state, and then combines the degradation characteristics of shear moduli taken from reloading curve. This procedure derives the shear moduli in overall strain range. Pressuremeter tests were carried out in various ground conditions using large calibration chamber, together with various reference tests. Shear moduli taken from pressuremeter tests were compared with bender element test and resonant column test results.

• Journal of Korean Society of Archives and Records Management
• /
• v.17 no.1
• /
• pp.93-115
• /
• 2017

In this study, the RiC-CM (Records in Context-Conceptual Model) draft of the International Council on Archives Expert Group on Archival Description (ICA EGAD) was analyzed, mapped with the descriptive elements of ISAD(G), and the archival description of the record group based on RiC-CM was piloted. This was done to identify trends in the archival descriptive standards and to derive considerations in relation to improving existing descriptive standards. The mapping types of RiC-CM and ISAD(G) include inter-attribute mapping, attribute-entity mapping, and attribute-relation mapping. In addition to the mapping between descriptive elements, a frame for the archival information that can construct a record through the objects, attributes, and relationships of RiC-CM is constructed using the protege, and the example data is inputted for trial. As a result, it was possible to express most of the existing descriptive information of ISAD(G) through RiC-CM. In addition, in RiC-CM, the recording descriptive information is classified in detail, and the characteristic of browsing the relation between individual objects is enhanced.

• Annual Conference of KIPS
• /
• 2001.10b
• /
• pp.1287-1290
• /
• 2001

현재 인터넷상에서 버디 리스트와 프레젠스 서비스가 폭발적인 증가하고 있고, 이들 서비스는 온라인 상태에서 인스턴트 메시지를 사용하고 있다. 그러나 이들 서비스들은 독자 사양에 따라 구현되어 강호호환성을 제공하지 않는다. 이를 해결하기 위해서 인터넷 표준 기구인 IETF (Internet Engineering Task Force)[1]의 IMPP (Instant Messaging and Presence Proto3col) 워킹그룹은 인스턴트 메시징과 프레젠스 서비스를 위한 기본골격(framework)을 표준화하였고, IMPP 를 따르는 메신저 프로토콜을 표준화하는 SIMPLE (SIP for Instant Messaging and Presence Leveraging) 워킹그룹과 APEX (Application Exchange) 워킹그룹을 구성하였다. 본 논문에서는 IETF SIMPLE 워킹그룹에서 제안만 SIP 기반 인스턴트 메시징과 프레젠스 기능을 갖는 메신저를 구현하였다. 구현 언어는 C++를 사용하였고 UA (User Agent)는 MS Windows 98/2000에서 구현하였고 인스턴트 메시징과 프레젠스 기능을 수행하는 메신저 서버는 Linux에서 구현하였다.

• Proceedings of the Korea Contents Association Conference
• /
• 2007.11a
• /
• pp.837-841
• /
• 2007

최근 영상을 중심으로 여러 형태의 정보를 결합하여 저장하거나 전송하는 멀티미디어가 많은 관심을 받고 있다. 현재 카메라와 관련된 동영상 캡처기술은 Motion JPEG이 주류를 이루고 있으며, 텔레비전, DMB 등의 방송 분야 및 DVD, VCR 분야에서는 MPEG-2, MPEG-4, H.264 및 WMV9 등의 압축 코덱이 채용되고 사용되고 있다. 그러나 이러한 다양한 영상 표준방식은 디코딩시 호환성 문제가 발생하게 되고 이에 따라 통합 코덱 연구가 필요하다. 이에 본 논문은 일반적 스텝 양자화외에 데드존 양자화를 사용하고 "$4{\times}4$", "$4{\times}8$", "$8{\times}4$", "$8{\times}8$"의 다양한 블록크기의 변환을 지원하는 VC-1을 기반으로 한 ITIQ C언어를 통해 시뮬레이션하고 최적화된 결과를 VHDL로 구현하여 향후 통합코덱 연구에 응용 가능하도록 연구 및 분석평가 하였다. 설계결과 4:2:0의 YCbCr포맷의 최초 $16{\times}16$블록을 복원하는데 483~510클록이 소요되었고 Xilinx XCVPC100 FF1696-6 환경에서 93,128개의 게이트 수와 71.469MHz의 동작속도를 나타내었다. 이는 640*480 크기의 컬러영상을 디코딩 하는데 프레임 당 최대 0.0074초가 소요됨을 의미하며 초당 30프레임의 영상에서도 0.222초면 디코딩이 가능한 결과이다.

• Journal of Hydrogen and New Energy
• /
• v.29 no.1
• /
• pp.56-63
• /
• 2018

In this study, a $100cm^2$ cell frame for a molten carbonate fuel cell was designed using CFD analysis. Electrochemical reactions, gas flow, and the heat transfer in $100cm^2$ cell frame were modeled using COMSOL Multiphysics. Two design variables such as the height of the cell frame and the length of the gas input area were determined to obtain minimized temperature distribution and uniform gas distribution. With two design parameter such as height of the cell frame and the length of the gas flow channel, the temperature difference in the cell fame was decreased to $5^{\circ}C$ and the gas uniformity in the flow channel were achieved.

• The Journal of the Acoustical Society of Korea
• /
• v.19 no.3
• /
• pp.57-62
• /
• 2000

In recent, the innovative improvement of a internet and computing environment make users desire the capability of processing information in real time. In this paper we implement a PC-to-PC real time multi-user communication system on the internet environment using the efficient algorithm for a real time processing and the MFEG-4 CELP codec which can be used for a low bit-rate coding from 6 to 24kbps. The implemented system produces a compressed bit-streams with the MPEG-4 CEU Mode-I 18200bps mode. There is 5 frames for a package and 1 frame has 160 samples. We can use this system to communicate with 4 users simultaneously in real time. The system is designed and examined on the Windows operating system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.11C
• /
• pp.1097-1105
• /
• 2002

In display systems employing analog monitors, the tearing artifact such that an window screen is divided into two parts showing different scenes can occur when the change of scenes in the moving pictures is very fast, but the frame buffer's refresh rate does not match the monitor's scanning frequency. It is especially noticeable at high frame rate. DVR system is a recently popularized visual monitoring system. The tearing artifacts becomes more serious since the frame buffer's refresh rate is very high due to the requirement of multi channel display in the DVR. In this paper, we propose an improved display system for windows-based DVR systems which prevents the tearing artifacts without deterioration of display speed performance. The efficiency of the proposed display system is verified through experiments.