• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.777-784
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• 2010

Recently, the necessity of underwater communication and demand for transmitting and receiving various data such as voice or high resolution image data are increasing as well. The performance of underwater acoustic communication system is influenced by characteristics of the underwater communication channels. Especially, ISI(inter symbol interference) occurs because of delay spread according to multi-path and communication performance is degraded. In this paper, we study the OFDM technique to overcome the delay spread in underwater channel and by using CP, we compensate for delay spread. But PAPR which OFDM system has problem is very high. Therefore, we use DFT-spread OFDM method to avoid nonlinear distortion by high PAPR and to improve efficiency of amplifier. DFT-spread OFDM technique obtains high PAPR reduction effect because of each parallel data loads to all subcarrier by DFT spread processing before IFFT. In this paper, we show performance about delay spread through OFDM system and verify method that DFT spread OFDM is more suitable than OFDM for underwater communication. And we analyze performance according to two subcarrier mapping methods(Interleaved, Localized). Through the simulation results, performance of DFT spread OFDM is better about 5~6dB at $10^{-4}$ than OFDM. When compared to BER according to subcarrier mapping, Interleaved method is better about 3.5dB at $10^{-4}$ than Localized method.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1487-1490
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• 2007

디지털 위성방송의 시작과 더불어 본격적인 데이터 방송의 시대가 열렸다. 데이터방송이 시작 되면서 데이터방송용 양방향 콘텐츠에 대한 수요가 급속하게 증가하고 있다. 하지만 양방향 콘텐츠 개발에 필요한 저작 도구 및 검증 시스템은 아주 초보적인 수준에 머물러 있는 것이 현실이다. 그러나 방송의 특성상 콘텐츠 상에서의 오류는 방송 사고에까지 이를 수 있는 심각한 상황이 연출 될 수 있다. 본 연구 팀은 이러한 DTV 콘텐츠 개발 요구에 부응하여, 개발자의 콘텐츠 개발 및 사업자 또는 기관에서의 콘텐츠 검증이 원활이 이루어 질수 있도록 하는 양방향 콘텐츠 검증 시스템을 개발 중이다. 양방향 콘텐츠 검증 시스템은 Java 컴파일러, 디버거, 미들웨어, 가상머신, 그리고 IDE 등으로 구성된다. 본 논문에서 제시한 자바 컴파일러는 양방향 콘텐츠 검증 시스템에서 데이터 방송용 자바 애플리케이션(Xlet)을 컴파일하여 에뮬레이팅 하거나 런타임 상에서 디버깅이 가능하도록 하는 바이너리형태의 class 파일을 생성한다. 이를 위해 Java 컴파일러는 *.java 파일을 입력으로 받아 어휘 분석과 구문 분석 과정을 거친 후 SDT(syntax-directed translation)에 의해 AST(Abstract Syntax Tree)를 생성한다. 클래스링커는 생성된 AST를 탐색하여 동적으로 로딩 되는 파일들을 연결하여 AST를 확장한다. 의미 분석과정에서는 확장된 AST를 입력으로 받아 참조된 명칭의 사용이 타당한지 등을 검사하고 코드 생성이 용이하도록 AST를 변형하고 부가적인 정보를 삽입하여 ST(Semantic Tree)를 생성한다. 코드 생성 단계에서는 ST를 입력으로 받아 이미 정해 놓은 패턴에 맞추어 Bytecode를 출력한다.ovoids에서도 각각의 점들에 대한 선량을 측정하였다. SAS와 SSAS의 직장에 미치는 선량차이는 실제 임상에서의 관심 점들과 가장 가까운 25 mm(R2)와 30 mm(R3)거리에서 각각 8.0% 6.0%였고 SAS와 FWAS의 직장에 미치는 선량차이는 25 mm(R2) 와 30 mm(R3)거리에서 각각 25.0% 23.0%로 나타났다. SAS와 SSAS의 방광에 미치는 선량차이는 20 m(Bl)와 30 mm(B2)거리에서 각각 8.0% 3.0%였고 SAS와 FWAS의 방광에 미치는 선량차이는 20 mm(Bl)와 30 mm(B2)거리에서 각각 23.0%, 17.0%로 나타났다. SAS를 SSAS나 FWAS로 대체하였을 때 직장에 미치는 선량은 SSAS는 최대 8.0 %, FWAS는 최대 26.0 %까지 감소되고 방광에 미치는 선량은 SSAS는 최대 8.0 % FWAS는 최대 23.0%까지 감소됨을 알 수 있었고 FWAS가 SSAS 보다 차폐효과가 더 좋은 것으로 나타났으며 이 두 종류의 shielded applicator set는 부인암의 근접치료시 직장과 방광으로 가는 선량을 감소시켜 환자치료의 최적화를 이룰 수 있을 것으로 생각된다.)한 항균(抗菌) 효과(效果)를 나타내었다. 이상(以上)의 결과(結果)로 보아 선방활명음(仙方活命飮)의 항균(抗菌) 효능(效能)은 군약(君藥)인 대황(大黃)의 성분(成分) 중(中)의 하나인 stilbene 계열(系列)의 화합물(化合物)인 Rhapontigenin과 Rhaponticin의 작용(作用)에 의(依)한 것이며, 이는 한의학(韓醫學) 방제(方劑) 원리(原理)인 군신좌사(君臣佐使) 이론(理論)에서 군약(君藥)이 주증(主症)에 주(主)로 작용(作用)하는 약물(藥物)이라는 것을 밝혀주는 것이라고

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.115-121
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• 2015

In this paper, we proposed an iterative data-flow optimal scheduling algorithm based on genetic algorithm for high-performance multiprocessor. The basic hardware model can be extended to include detailed features of the multiprocessor architecture. This is illustrated by implementing a hardware model that requires routing the data transfers over a communication network with a limited capacity. The scheduling method consists of three layers. In the top layer a genetic algorithm takes care of the optimization. It generates different permutations of operations, that are passed on to the middle layer. The global scheduling makes the main scheduling decisions based on a permutation of operations. Details of the hardware model are not considered in this layer. This is done in the bottom layer by the black-box scheduling. It completes the scheduling of an operation and ensures that the detailed hardware model is obeyed. Both scheduling method can insert cycles in the schedule to ensure that a valid schedule is always found quickly. In order to test the performance of the scheduling method, the results of benchmark of the five filters show that the scheduling method is able to find good quality schedules in reasonable time.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.326-333
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• 2005

Phase-only encryption scheme using exclusive-OR rules in Fourier plane and a single path decryption system are presented. A zero-padded original image, multiplied by a random phase image, is Fourier transformed and its real-valued data is encrypted with key data by using XOR rules. A decryption is simply performed based on 2-1 setup with spatial filter by Fourier transform for multiplying phase-only encrypted data by phase-only key data, which are obtained by phase-encoding process, and spatial filtering for zero-order elimination in inverse-Fourier plane. Since the encryption process is peformed in Fourier plane, proposed encryption scheme is more tolerant to loss of key information by scratching or cutting than previous XOR encryption method in space domain. Compare with previous phase-visualization systems, due to the simple architecture without a reference wave, our system is basically robust to mechanical vibrations and fluctuations. Numerical simulations have confirmed the proposed technique as high-level encryption and simple decryption architecture.

• Cartoon and Animation Studies
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• s.36
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• pp.553-572
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• 2014

In this paper, for the evaluation of the ease of a particular Web site (www.appbelt.net), insert the log tracking code for Google Analytics in a page of the Web site to collect behavioral data of visitor and has studied the improvement measures for the problems of the Web site, after the evaluation of the overall quality of the Web site through the evaluation of Coolcheck. These findings set the target value of the company's priority (importance) companies want to influence the direction of the business judgment are set up correctly, and the user's needs and behavior will be appropriate for the service seems to help improvement.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.322-326
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• 2006

Though human being has ability to percept a full colored vision, the technology of early photography only can produce black and white images. For cinema filming imagery also captured mono tone with black and white, until developed a color film technology. The desire for presenting color imagery and the technique for producing film and color ink, photography and print utilize color on it with noticeable color impact to viewers. It, however, abusing fun colors image each and every printed and filmed imagery, the freshness of eye catching power diminished now. On contrast, color becomes black and white or partially used for making discrepancy among full colored images. This image detected commercial and music video, and it spread to film. To use those bleached color images is for evoking a nostalgia and a visual differentiation. Especially, it can be provocative images brought to audience with that. such as "Anycall", "Dimchae" for CF, and "Schindler's list," and "Sin city" for movie. It is hard to investigate on the color studies for partially used images. Therefore, this study is to research that through CF and film, base on it, to investigate the application for this image. To collect data from survey, it will be established a basic concept for understanding the partial color applying.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.122-126
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• 2014

Purpose: The new reconstruction algorithms (NRA) provided by vendor aim to shorten the acquisition scan time. Whereas depending on the installed version AutoQuant program used for myocardial SPECT quantitative analysis did not contain the normal data that NRA is applied. Thus, the purpose of this paper is to compare the results according to AutoQuant versions in myocardial SPECT applied NRA and half-time scan (HT). Materials and Methods: Rest Tl and stress MIBI data of total 80 (40 men, 40 women) patients were gathered. Data were applied HT acquisition and ASTONISH (Philips) software which is NRA. Modified autoquant of SNUH and old version of AutoQuant (full-time scan) provided by company were compared. Comparison groups were classified as coronary artery disease (CAD), 24 hrs delay and almost normal patients who have a simple pain patient. Perfusion distribution aspect, summed stress score (SSS), summed rest score (SRS), extent and total perfusion deficit (TPD) of each 25 patient who have above diseases were compared and evaluated. Results: The case of CAD, when using re-edited AutoQuant (HT) SSS and SRS showed about 30% reduction (P<0.0001), Extent showed about 38% reduction and TPD showed about 30% reduction in the tendency (P<0.0001). In the score of the perfusion, especially on the part of infero-medium, infero-apical, lateral-medium and lateral-apical regions were the biggest change. The case of the 24 hrs delay patient SRS (P=0.042), Extent (P=0.018) and TPD (P=0.0024) showed about 13-18% reduction. And the case of simple pain patient, comparison of 4 results showed about 5-7% reduction. Conclusion: This study was started based on expectation that results could be affected by normal patient data. Normal patient data is possible to change by race and gender. It was proved that combination of new reconstruction algorithm for reducing scan time and analysis program according to scan protocol with NRA could also be affected to results. Clinical usefulness of gated myocardial SPECT is possibly increased if each hospital properly collects normal patient data for their scan acquisition protocol.

• Journal of Broadcast Engineering
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• v.25 no.2
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• pp.166-175
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• 2020

Recently, application fields for processing and using digital image contents in various forms and types are rapidly increasing. Since image content is high value-added content, the intellectual property rights of this content must be protected in order to activate the production and use of the digital image content. In this paper, we propose a deep learning based watermark embedding and extraction network. The proposed method is to maximize the robustness of the watermark against malicious/non-malicious attacks while preserving the invisibility of the host image. This network consists of a preprocessing network that changes the watermark to have the same resolution as the host image, a watermark embedding network that embeds watermark data while maintaining the resolution of the host image by three-dimensionally concatenating the changed host image and the watermark information, and a watermark extraction network that reduces the resolution and extracts watermarks. This network verifies the invisibility and robustness of the proposed method by experimenting with various pixel value change attacks and geometric attacks against various watermark data and host images with various resolutions, and shows that this method is universal and practical.