• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.11a
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• pp.200-200
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• 2001

백판지 면성은 표면 백색도의 변이, 불투명도의 변이, 광택도, 거치름도, 표면 지합, 표면 요철 등 다양한 인자들로 표현되고 있다. 인쇄소에서는 인쇄를 하기 때문에 화선 부에서의 백색도나 불투명도 등은 크게 불만 요소로 작용하지는 않으나 표면 요철의 경우에는 인쇄 후 화선부에서도 나타나기 때문에 고객 불만의 한 요소로 인식되어 진 다. 따라서 본 연구에서는 백판지 면성의 여러 인자 중 표면 요철의 평가에 대해 다루 고자 하였다. 백판지 표면 요철을 시각적으로 나타내기 위한 방법으로 3-Dimensinal topography를 얻을 수 있는 Zygo와 Stylus를 이용, FFT 변환을 통하여 2-dimensional topography를 얻는 방법이 연구되었다. 그러나 기자재 비용, 측정 시간 등의 문제 등으로 표면 요철 을 평가하기 어려운 점이 있다. 본 연구에서는 백판지를 T APIO를 이용하여 O.2mm간격으로 두께를 측정하였고 A verage slope와 Profile length라는 개념을 도입하여 수치 적으로 표면 요철을 정 량화 하였다. Average slope는 1mm 간격으로 이동하였을 때 높이의 편차를 평균하는 값이다. 또 한 Video eam을 이용하여 표면 요철의 형태를 촬영하여 시각적으로 판단할 수 있도록 하였다. 위의 측정 방법으로 국내, 외 12개의 Sample에 대해 Profile length와 Average s slope를 계산하였다. 고객의 주관적 평가를 의사결정 방법 중 하나인 AHP법을 이용하여 주관적인 정성 평가를 수치적으로 정량화할 수 있었으며 실제 측정 결과와 비교, 상관분석을 실시 하 였다. 고객의 평가 결과와 Profile length, average slope의 상관성을 분석한 결과 A Average slope에서 유의성 있는 상관성을 얻을 수 있었고 표면 사진을 비교하였을 때 C Coating 방식 등을 유추할 수 있었다. 이러한 평가 방법을 현장에 적용하였으며 그 결과, 공정 개선 전, 후의 표변을 측정, 개선 유무를 쉽게 판단할 수 있었다.

• Journal of the Korea Furniture Society
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• v.26 no.2
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• pp.179-185
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• 2015

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood G. biloba, ring-porous wood A. altissima, and diffuse- porouswood D. kaki. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents (MC). The length, lumen diameter, pit diameter, end wall pit diameter and the numbers of end wall pits determined for the flow rate. The liquid flow in the those cells was captured via video and the capillary flow rate in the ones were measured. Vessel in hardwood species and tracheids in softwood was found to facilitate prime role in longitudinal penetration. Radial flow speed was found highest in ray parenchyma of G. biloba. Anatomical features like the length and diameter, end-wall pit numbers of ray parenchyma were found also responsible fluid flow differences. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Therefore, the average liquid penetration depth in longitudinal tracheids of G. biloba was found the highest among all cells considered in D. kaki and A. altissima.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.1
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• pp.87-94
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• 2012

Purpose : The purpose of this study was to examine the feasibility and efficiency of balance training program through an interactive video game regimen in people with chronic stroke. Methods : Thirty patients with chronic hemiparetic stroke were recruited. Participants were randomly assigned to either a control group (n=15) or an experimental group (n=15). The control group received the general physical therapy including of strengthening and balance exercise five times a week whereas the experimental group received a program of balance exercise with video game play based on virtual reality as well as the same typical physical therapy. The experimental group received 6 sessions for four weeks. Each session was given 5 minutes. An interactive computer game exercise regimen lasted 30 minutes without rest periods. Outcome measures for weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-standspeed and sit-to-stand-area for the control group (n=15) and experimental group (n=15) before and after treatment were obtained by using the biorescure. Results: Outcomes demonstrated significant improvement in the experimental group compared with the control group in weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-stand-speed. No significant training effect was showed in sit-to-stand-area between pretraining and post-training. Conclusion : An interactive computer game exercise based on task oriented approach for balance in chronic stroke were feasible. In other words, This regimen resulted in a greater improvement in dynamic balance for people with chronic stroke.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.579-586
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• 2001

Digital watermarking is to embed imperceptible mark into image, video, audio, and text data to prevent the illegal copy of multimedia data. arbitrary modification, and also illegal sales of the copies without agreement of copyright ownership. In this paper, we study for the embedding and extraction of watermark key using wavelet in the luminance signal in order to implement the system to protect the copyright for image MPEG. First, the original image is analyzed into frequency domain by discrete wavelet transform. The RSA(Rivest, Shamir, Aldeman) public key of the coded target is RUN parameter of VLD(variable length coding). Because the high relationship among the adjacent RUN parameters effect the whole image, it prevents non-authorizer not to possess private key from behaving illegally. The Results show that the proposed method provides better moving picture and the distortion more key of insert than direct coded method on low-frequency domain based DCT.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.289-296
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• 2019

Recently, the development of smartphone camera technology enables to shoot high quality video. In order to utilize these techniques in various ways, it is necessary to be able to transmit signals to an external device such as a external display. The transmission performance of the video signal is determined by the loss of the transmission line and the length of the wiring. In this paper, we propose the HDMI transmission line design criterion according to the wiring length changed according to the smartphone design and the surface roughness amplitude of the printed circuit board conductor wiring material. Also, we verified the proposed design criteria for the actual smartphone design. The proposed design criterion can be applied to various application fields including high-speed signal transmission line besides mobile application.

• Journal of Chest Surgery
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• v.56 no.1
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• pp.35-41
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• 2023

Background: We analyzed our experience with descending necrotizing mediastinitis (DNM) treatment and investigated the efficacy of video-assisted thoracoscopic surgery (VATS) for mediastinal drainage. Methods: This retrospective analysis included patients who underwent surgical drainage for DNM at our hospital from 2005 to 2020. We analyzed patients' baseline characteristics, surgical data, and perioperative outcomes and compared them according to the mediastinal drainage approach among patients with type II DNM. Results: Twenty-five patients (male-to-female ratio, 18:7) with a mean age of 54.0±12.9 years were enrolled in this study. The most common infection sources were pharyngeal infections (60%). Most patients had significantly increased white blood cell counts, elevated C-reactive protein levels, and decreased albumin levels on admission. The most common DNM type was type IIB (n=16, 64%), while 5 and 4 patients had types I and IIA, respectively. For mediastinal drainage, the transcervical approach was used in 15 patients and the transthoracic approach (VATS) in 10 patients. The mean length of hospital stay was 26.5±23.8 days, and the postoperative morbidity and in-hospital mortality rates were 24% and 12%, respectively. No statistically significant differences were found among patients with type II DNM between the transcervical and VATS groups. However, the VATS group showed shorter mean antibiotic therapy duration, drainage duration, and hospital stay length than the transcervical group. Conclusion: DNM manifested as severe infection requiring long-term inpatient treatment, with a mortality rate of 12%. Thus, active treatment with a multidisciplinary approach is crucial, and mediastinal drainage using VATS is considered relatively safe and effective.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.849-860
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• 2007

Because the H.264/AVC standard adopts the variable length coding algorithm, the rate of encoded video bitstream fluctuates a lot as time flows, though its compression efficiency is superior to that of existing standards. When a video is transmitted in real-time over networks with fixed low-bandwidth, it is necessary to control the bit rate which is generated from encoder. Many existing rate control algorithms have been adopting the quadratic rate-distortion model which determines the target bits for each frame. We propose a new rate control algorithm for H.264/AVC video transmission over networks with fixed bandwidth. The proposed algorithm predicts quantization parameter adaptively to reduce video distortion using the quadratic rate-distortion model, which uses the target bit rate and the mean absolute difference for current frame considering pixel difference between macroblocks in the previous and the current frame. On video samples with high motion and scene change cases, experimental results show that (1) the proposed algorithm adapts the encoded bitstream to limited channel capacity, while existing algorithms abruptly excess the limit bit rate; (2) the proposed algorithm improves picture quality with $0.4{\sim}0.9dB$ in average.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.138-148
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• 2001

Digital Video (DV) coding standards for digital video cassette recorder are based mainly on DCT and variable length coding. DV has low hardware complexity but high compressed bit rate of about 26 Mb/s. Thus, it is necessary to encode video with low complex video coding at the studios and then transcode compressed video into MPEG-2 for video-on-demand system. Because these coding methods exploit DCT, transcoding in the DCT domain can reduce computational complexity by excluding duplicated procedures. In transcoding DV into MPEC-2 intra coding, multiplying matrix by transformed data is used for 4:1:1-to-4:2:2 chroma format conversion and the conversion from 2-4-8 to 8-8 DCT mode, and therefore enables parallel processing. Variance of sub block for MPEG-2 rate control is computed completely in the DCT domain. These are verified through experiments. We estimate motion hierarchically using DCT coefficients for transcoding into MPEG-2 inter coding. First, we estimate motion of a macro block (MB) only with 4 DC values of 4 sub blocks and then estimate motion with 16-point MB using IDCT of 2$\times$2 low frequencies in each sub block, and finish estimation at a sub pixel as the fifth step. ME with overlapped search range shows better PSNR performance than ME without overlapping.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.416-428
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• 2001

In order to build a news archive system. the news video stream should be first segmented into several articles, ad their contents are abstracted effectively. This abstraction helps the users to understand the contents of the article without playing the whole video stream. This paper proposes a new article boundary detection scheme for the news video streams together with a new news article abstraction scheme using the shot types of the news video data. The shots in the news video are classified into anchor person shots, interview shots, speech shots, reporting shots, graphic shots, and others. Since the news article starts with an anchor shot whose duration is relatively longer than other shots with special screen structure, the article boundary in detected by the computing the length of the shot and checking the screen structure in the proposed scheme. For the effective abstraction of the article video, the graphic image located in the right-top of the anchor shot frames is primarily used in the proposed abstraction scheme since it is the abstraction of the article made by the producer of the news according to its contents so that it contains a lot of meaningful information. The key frames of the other shots except interview and report shots are also used to abstract the contents of the articles in the proposed scheme. Upon experimental results, the precision and recall values of the proposed article boundary detection scheme could be 92% and 96%, respectively. This paper also presents a design and implementation of a prototype news archive system on WWW that consists of an indexing tool, an authoring tool, a database for meta-data of the news, and a browsing tool.

• Information Systems Review
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• v.22 no.2
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• pp.25-41
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• 2020

Along with the expectation about 5G network commercialization, interests in realistic and immersive media industries such as virtual reality (VR) are increasing. However, most of studies on VR still focus on video technologies instead of factors for popularity and consumption. Thus, the main objective of this research is to identify meaningful factors, which affect the view counts of VR videos and to provide business implications of the content strategies for VR video creators and service providers. Using a regression analysis with 700 VR videos, this study tries to find major factors that affect the view counts of VR videos. As a result, user assessment factors such as number of likes and sicknesses have a strong influence on the view counts. In addition, the result shows that both general information factors (video length and age) and content characteristic factors (series, one source multi use (OSMU), and category) are all influential factors. The findings suggest that it is necessary to support recommendation and curation based on user assessments for increasing popularity and diffusion of VR video streaming.