• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2B
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• pp.129-137
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• 2003

Multimedia streams, like MPEG continuously retrieve multimedia data because of their incessant playback. While these streams need an efficient support of kernel, the current buffer cache mechanism of Linux kernel such as Unix operating system was designed apt for small files, which is aperiodically requested as well as time uncritical. But, in case of continuous media, the CPU must enormously copy memory from kernel address space to user address space. This must lead to a large CPU overhead. This overhead both degrades system throughput and cannot guarantee QOS. In this paper, we have designed and implemented two memory copy reduction schemes in Linux kernel, direct I/O and one copy. The direct I/O skips the buffer cache layer of Linux kernel and results in dramatic reduction of CPU memory copy overhead. And, the one copy provides a fast disk-to-network data path without copying to user address space. The experimental results show considerable reduction of CPU overhead and throughput improvements.

• Journal of Engineering Education Research
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• v.18 no.5
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• pp.32-41
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• 2015

This paper deals with analyzing accreditation findings and the causes for the deficiencies in the review by the EAC(Engineering Accreditation Committee) of ABEEK in 2014. For this purpose Final Statements of the 266 engineering education programs reviewed by the EAC of ABEEK in 2014 were analyzed on the basis of the each criterion. However, Accreditation Criterion 8(Program Criterion) was excluded in the analysis of the causes for the deficiencies since the program-specific requirements within areas of specialization might vary with the program criteria. As results of accreditation review by the EAC of ABEEK, Deficiency findings were 81 cases which made up 3.81% of total findings, Weakness findings were 1,679 which made up 78.91% of total findings, Concern findings were 124 cases which made up 5.83% of total findings, and Satisfaction findings were 244 cases which made up 11.47% of total findings. Deficiency and Weakness findings against which the relevant program must take actions for the improvement were 82.71% in all. The findings on program accreditation are made on the basis of the Accreditation Actions Guide. Accordingly, in view of formal logic in the accreditation review, the accreditation findings should comply with the Accreditation Actions Guide consistently. In this respect, the Deficiency findings in the accreditation review can be justified. So it is useful for a program or an institution which prepares for the accreditation review to check over the causes for the Deficiency against the Accreditation Actions Guide. On the other hand changeover in the accreditation policy of the ABEEK may be necessary. If the quality of the engineering education is improved continuously through the accreditation review, accreditation fulfills its purpose. To gain this end it is important to place higher value on the 'bigger picture' than on the minor details. In other words, "holistic" evaluation of evidence should form the basis of accreditation review.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4780-4785
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• 2012

As many mobile devices such as smart phones and tablets are widely spread, optimized mobile video encoder used during video recording application is needed. In this paper, we implemented H.264/AVC base profile video encoder on a mobile device and empirically optimized control parameters of the encoder. As the experiment, we more than 100 test cases were designed with varying Lagrangian optimization, Hadamard Transform, search range, I-frame period, and reference frames. During the experiment, we measured picture quality, bit-rate, encoding time, motion estimation time, and power consumption. From the result, we can determine optimal values for the H.264 control parameters.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4459-4463
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• 2014

Background: Gastric cancer is the second leading cause of cancer-related deaths worldwide and infection with H. pylori is considered essential for its development. Helicobacter pylori infects more than 50% of the world's population with higher prevalence in developing countries than developed countries. The prevalence of H. pylori varies in different societies and geographical locations. The objectives of this study were to estimate the seroprevalence and determine the risk factors of H. pylori infection in dyspeptic patents in Ethiopia. Materials and Methods: A cross-sectional study involving 209 dyspeptic patients was carried out from February 15 to April 30, 2013. Five to ten ml venous blood was collected from each dyspeptic patient and analyzed for detection of Helicobacter pylori immunoglobulin (IgG). The socio-demographic characteristic, hygienic practices, alcohol consumption, sources of drinking water and types of latrine were also obtained with a pre-tested questionnaire. Results: The overall seroprevalence of Helicobacter pylori was 72.2%. There was statistically significant difference in the prevalence of H. pylori among age groups (p=0.02). Seroprevalence of H. pylori was higher in those patients who used unprotected surface water (76.4%) than those with access to piped tap water (65.9%). There was also statistically significant differences in prevalence of H. pylori with the habit of hand washing before meal (p=0.01) and alcohol consumption (p=0.001). Conclusions: The prevalence of H. pylori was high in the study area and increased with age of dyspeptic patients. Alcohol consumption and the type of drinking water are risk factors that have associations with the prevalence of H. pylori. Molecular epidemiological techniques can show a true picture of H. pylori and improvement in the drinking water quality is recommended.

• Imaging Science in Dentistry
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• v.47 no.2
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• pp.87-92
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• 2017

Purpose: The aim of this study was to determine whether the panoramic mandibular index (PMI) is useful for assessing bone mineral density. We also analyzed the potential correlations between PMI parameters and patient age. Materials and Methods: Four observers measured the PMI of both sides of the mental foramen using a picture archiving and communication system and images in the Digital Imaging and Communications in Medicine format. They studied 300 panoramic radiographic images of patients belonging to the following age groups: 40-49 years, 50-59 years, 60-69 years, 70-79 years, and 80-89 years. The observers were allowed to zoom in or out and to adjust the contrast of the images. Further, they were instructed to record the reasons for any measurements that could not be made. Then, we conducted a reliability analysis of the measured PMI and assessed the correlations between different patient age groups and the 3 parameters used for determining the PMI from the available data. Results: Among the 600 data items collected, 23 items were considered unmeasurable by at least 1 observer for the following 4 reasons: postoperative state, lesion, unidentified mental foramen, and alveolar bone loss. The intraobserver reproducibility of the measurable data was 0.611-0.752. The mandibular cortical width (MCW) decreased significantly as patient age increased. Conclusion: PMI had limited usability when the margin of the mental foramen was not clear. In contrast, MCW, a parameter used for determining the PMI, had fewer drawbacks than the PMI with respect to bone mineral density measurements and exhibited a significant correlation with patient age.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.1
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• pp.41-50
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• 2020

The National Geographic Information Institute of Korea takes digital aerial photograph images every two years to make and modify/renew the digital map. The cameras for aerial photogrammetry to capture these digital aerial photographs are divided into frame types and line types. Computer vision analysis of aerial photograph images was only possible for frame type. Thus, in this study, Line type aerial photograph images was intended to generate geospatial information through computer vision analysis, and forest geospatial information was created as a method for the utilization of aerial picture images. As a result, geospatial information generated by computer vision analysis of line type aerial photograph images showed that RMSE of horizontal and vertical position errors was less than quadruple that of GSD. Forest geospatial information was generated using geospatial information generated by computer vision analysis. It was confirmed that extraction of the crown of tree and calculation of tree height are possible. Through this study, it is expected that utilization of aerial photograph images will be improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4498-4510
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• 2015

The purpose of this study is to investigate effective teaching media for infants' teaching-learning process by comparing the effects of multimedia fairytale activities and picture fairytale listening activities on infants' prosocial actions. Following the purpose of this study, we studied any effect to infants' prosocial actions from multimedia fairytale activities by dividing in two groups. This study was conducted with 5-year-old infants (total 40; 20 experimental group & 20 comparison group) in D daycare center in Daejeon. Verifying data tool were time series corresponding t-test, independent t-test and multi-variant analyses. As a result, multimedia fairytale listening activities are more effective for infants' prosocial actions. It has meaningful difference in the interpersonal relationship skills and early childhood education adapt which is sub-area of infant's prosocial actions. So, for various and high-quality early childhood education, using multimedia teaching media is more effective than existing teaching media.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.672-686
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• 2002

현재 단대단(End-to-End) 비디오 서비스의 질을 높이기 위해 많은 연구가 각 계층별로 진행되고 있다. 전송계층에서의 오류 제어(Error Control), 네트워크계층에서의 QoS (Quality of Service)모델, 표현 및 응용계층에서의 오류 강인성(Error resilience)/오류 은닉(Error concealment) 등이 연구 개발되고 있다. 그러나 계층 간의 연관성이 높은 부분에서의 통합을 통한 성능향상에 관한 연구는 그 필요성과 효율에 비해 아직도 미흡하다. 본 논문은 QoS 서비스 모델하에서의 적응적 FEC(Forward Error Correction) 적용 및 우선순위에 따른 비디오패킷(VP ,VideoPacket)을 통하여 효율적인 계층화 비디오 스트리밍을 단대단 QoS성능의 향상에 관점을 맞추어 제안한다. 제안하는 방식은 최소 화질 보장과 같은 효율에서 보다 적은 가격에서의 서비스를 제공할 수 있다. 이를 위하여 통합형 서비스(IntServ, IS, Integrated Service) 의 자원예약을 사용하는 방법과 높은 가격의 자원 예약을 사용하지 않는 차별화 서비스(DiffServ, DS, Differentiated Service)를 적용했으며 이에 보장형 서비스의 특징을 공통을 가지기 위해 계층화 FEC를 적용하였으며 적절한 가격의 조절을 위하여 비디오패킷을 통한 데이터 분할을 적용하였다. 본 논문은 또한 최종 사용자의 만족도를 PSNR(Picture Signal to Noise Ration)과 PSNR에서 표현하지 못하는 부분의 평가를 위해 손상프레임율(DFR, Damaged Frame Ratio)과 오류프레임율(EFR,Error Frame Ratio)을 제안 이를 통해 평가하고자 한다. 제안하는 방식의 실험 결과는 비디오 코딩계층과 전송 계층, 네트워크 계층의 결합된 성능이며 이는 또한 화질의 개선뿐만 아니라 사용자의 가격문제에 대하여서도 비교 분석하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.149-159
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• 2001

The conventional block-based motion prediction suffers, especially in low bit-rate video application, from shortcomings such as blocking artifacts of motion field and unstable motion estimation. To overcome the deficiency, this paper proposes one method of adopting a new motion compensation scheme based on the irregular triangular mesh structure while keeping the current block-based DCT coding structure of H.263 as much as possible. To represent the reconstructed previous frame using minimal number of control points, the proposed method designs content-adaptive irregular triangular meshes, and then, estimate the motion vector of each control point using the affine transformation-based matching. The predicted current frame is obtained by applying the affine transformation to each triangular mesh. Experiment with the several real video sequences shows improvement both in objective and subjective picture quality over the conventional block-based H.263 method.

• Journal of Internet Computing and Services
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• v.13 no.1
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• pp.57-63
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• 2012

Recently, Development of high-speed internet networks can be a real-time video conference system. SD-quality still images using the software codec system exists, and two-way system with mobile systems, but in most video only send and receive video system. In this study, HD web-cam using the two-way live broadcasts simultaneously in the education system and the mobile system has developed an audible system. In the study using the H.264 standard video compression techniques were applied to high-bandwidth compression technology, smart phones, to develop a streaming server for broadcasting were applied. Video sharing, document, web-sharing was made possible in real time. In addition, the private IP for WiFi zone, available anytime, anywhere that can be converted to a public IP technology, IP tunneling technology applied.