흉부 X선촬영 기술의 변천에 관한 연구

이창엽,조평곤,김지닐,최소영,김창균,최종학,김정민,김유현 高麗大學校 倂設 保健大學 保健科學硏究所 2002 保健科學論集 Vol.28 No.2

To find elements which enable improving Quality of image of chest radiography, we attempted to make comparison between chest radiography used currently with that of the past, and following conclusion was reached: 1) It could be confirmed that a dependance on chest radiography was declining, because proportion of chest radiography against overall radiography decreased. 2) There was a change of kVp to a high voltage in a chest radiography, and use of high kVp became a generalization 3) Exposure time was reduced and exposure dose was curtailed accordingly. 4) Apparatus was mainly comprised of 3-phase rectifier circuit and inverter type. 5) It could be confirmed that frequency of applying additional filters for high kVp radiography was insufficient. 6) There was almost no difference in the condition of exposure between hospitals using film/screen and hospitals using CR. But when CR is used for radiography, it was increase in exposure dose due to increase in tube current and it will be necessary to have continuous study on exposure dose by an increase use of CR in the future.

변환영역에서의 3D 워터마킹

김성준,김정엽,현기호 영산대학교 2004 영산논총 Vol.13 No.-

Recently, copyright of 3D data model being taken in methods to protect the copyright of data and preventing illegal duplication of it. in this paper, we are comparative analysis about watermarking method in transform domain of 3D data model. 3D Watermarking is being taken coordinate value and connectivity information. Watermark embeding to middle domain of coefficient value in WT(wavelet transtorm) and DCT(discrete cosine transform). First method that insert water mark data to WT coefficient value stand on basis of the WT of Kanai's 3D data model and MRR(multi resolution representation). Second method that insert water mark data to 3D data model's DCT coefficient value stand on basis of the Jeong-Hee Jeon's triangle-strip. And, I study on comparing of two methods and analyzing the merits and demerits of two methods.

감응성막의 전기적 성질을 이용한 유기 가스 반응 특성

김도균,이준호,유승엽,장정수,권영수 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The electrical properties of Maleate copolymer (C_(18)MA-VE_(2)) and Itaconate copolymer (C_(18)ITA-VE_(2)) Langmuir-Blodgett (LB) films for in-plane were investigated to develop the gas sensor. The C_(18)MA-VE_(2) and C_(18)ITA-VE_(2) were used as sensitive materials and deposition on the slide-glass substrate using LB method which could control the thickness in the molecular order (Å). The current-voltage (I-V) characteristics were measured to investigated the response characteristics in chloroform, acetone, ethanol and methanol gases. The conductivity of sensitive films were 10^(-)7[S/cm] for an in-plane. The change of conductivity was occurred by behavior of organic gases, which mean that the behavior of organic gases could be analyzed using conductivity change and application to gas sensor. In the experimental results, the relation between sensitive films and organic gases could be divided by three-type. Thus, we could analyze the modeling of the response characteristics of organic gases using the conductivity change of sensitive films.

Griesmer bound의 등호를 만족하는 [2^k-1+k, k, 2^(k-1)+1] 부호의 설계 방법

김정헌,송홍엽 연세대학교 전파통신연구소 2001 電波通信論文誌 Vol.5 No.1

모든□이진 부호는 Griesmer bound □를 만족해야 한다. 본 논문에서는 Griesmer bound의 등호를 만족하는 □부호의 간단한 설계법을 소개하고 Helleseth 부호 관점에서 본 새로운 표현법을 소개한다. Any □binary linear code must satisfy the Griesmer bound □Here, a simple construction of □codes which achieves the equality of the Griesmer bound is introduced and its another description in view of the codes of Helleseth is presented.

주파수 영역을 이용한 비디오 워터마킹에 관한 연구

김정엽,현기호,최용수 영산대학교 2004 영산논총 Vol.14 No.-

Wavelet transformation which has special qualties of frequency domain and spatial domain is used for watermarking. In this paper, we compare and analyze a technique for embedding the watermark of visually recognizable patterns into the frequency domain of the digital video. In Kwon's method, each video frame is decomposed into four-level by DWT which reveals the characteristics of the human eyes and watermark is embedded into DWT coefficients using HVS. we study for the embedding and extraction of watermark key using wavelet in the luminance signal in order to implement the copyright for image MPEG First, the original image is analyzed into frequency domain by discrete wavelet transform. The RSA public key of the coded target is RUN parameter of VLC. a digital video watermarking algorithm is analyze that uses HVS and DWT.

DCT 기반의 MPEG 비디오 워터마킹 기법

김준수,김정엽,현기호 영산대학교 2004 영산논총 Vol.13 No.-

The development and spread of multimedia services require authentication techniques to prove the originality and integrity of multimedia data and to localize the alterations made on the media. A wide variety of authentication techniques have been proposed in the literature. In this paper, We study the embeding watermark of the compressed video sequence for copyright protection. We does compare and analyse two watermarking method using spread spectrum scheme in DCT frequence domain. This methods that the object detect using motion vector and transformation of codeword in VLC domain is show the robustness to the attacks like average operation or statistical analysis.

영아에 발생한 하마종

정정권,윤규호,전인성,김기엽,김현우,권순욱 大韓顎顔面成形再建外科學會 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.5

The ranula is a form of mucocele which specifically occurs in the floor of the mouth. The ranula is classfied into simple ranula and plunging ranula according to the mechanism of development such as the salivary duct obstruction or the extravasation. Clinically this lesion develops as a slowly enlarging painless, fluctuant mass on one side of the floor of the mouth and the mucosa may have a translucent bluish color. An 8-month-old male infant visited our hospital with the chief complaint of the left submandibular swelling and the mass on the floor of the mouth. We tentatively diagnosed a simple ranula. The marsupialization was performed but the sign and the symptom did not subside, so we took the MRI. By the MRI we diagnosed a plunging ranula and excised the sublingual gland via the intraoral approach. The correct diagnosis is essential for the most effective treatment, which is the excision of the sublingual gland.

複合非破壞試驗法을 利用한 現場콘크리트 强度推定에 關한 硏究

조철희,김하진,이승엽,김정섭 朝鮮大學校 建設技術硏究所 1999 建設技術硏究 Vol.19 No.1

This study is to improve the reliability of compressive strength estimation using combined non-destructive testing method in estimating the compressive strength of in-situ concrete after 730 days of age, measures the values of compressive strength and non-destructive test of in-situ concrete with the combined strength of 240kg/㎠, conducts the experiment for estimating the compressive strength, makes the estimation expression of the results through simple and duplicate regressive analysis and then the results of comparing and analyzing to existing expressions to secure the range of application of estimation expression and its reliability are as follows. It is found that the positive curing is very important in the early curing of the strength revelation in long-term age and especially in hydrate and it is considered that the formation and application of estimation expression of comprressive strength according to placement and curing method are needed to enhance the degree of strength estimation of in-situ concrete. After 365 days of age, the compressive strength of concrete tends to be decreased. While the single method has not a great change of non-destructive test value according to the change of concrete strength, the combined method shows a high reliability and then it is appropriate to use it for the exact strength estimation. Existing estimation expression used for estimating the compressive strength indicates a high estimation error in comparison with the expression suggested by this research in the difference of materials used, combined strength of concrete and the difference of placement and curing methods. Accordingly, it will be desirable to use an estimation expression suitable to the in-situ conditions for the exact strength estimation. The estimation expression of compressive strength using combined non-destructive test method of in-situ concrete on 730 days of age (2 years) suggested by this research is as follows. Air Curing fc' = 7.33R+219Vp-846 [R-sq(adj) = 0.839, N=81] Water Curing fc' = 12.6R+176Vp-805 [R-sq(adj) = 0.839, N=81]

Key을 이용한 디지털 이미지 워터마킹에 관한 연구

정송균,김정엽,현기호 영산대학교 2003 영산논총 Vol.11 No.-

In this paper, we reviewed and compared the methods uses the key as watermark and key with watermark. And we found some methods using the key in watermarking on the frequency domain which were robust to arbitrary attack. At first, the image was transformed to frequency domain by DWT(Discrete Wavelet Transform) in the methods uses the key as watermark, and then the watermark was inserted and extracted in the high frequency region on the transformed image. The second one uses the key with watermark transforms the image into frequency domain by DCT(Discrete Cosine Transform) and inserts the watermark on the mid frequency region that is selected by human visual characteristics. This method also inserts and extracts the watermark with minimum effect to the image quality by using multiple thresholds to maximize the image quality. Experimental results shows the second method using the key with watermark has higher PSNR compared to the other method for the watermark extraction.

Korean Red Ginseng suppresses emphysematous lesions induced by cigarette smoke condensate through inhibition of macrophage-driven apoptosis pathways

Jeong-Won Kim,Jin-Hwa Kim,Chang-Yeop Kim,Ji-Soo Jeong,Je-Won Ko,Tae-Won Kim The Korean Society of Ginseng 2024 Journal of Ginseng Research Vol.48 No.2

Background: Cigarette smoke is generally accepted as a major contributor to chronic obstructive pulmonary disease (COPD), which is characterized by emphysematous lesions. In this study, we investigated the protective effects of Korean Red Ginseng (KRG) against cigarette smoke condensate (CSC)-induced emphysema. Methods: Mice were instilled with 50 mg/kg of CSC intranasally once a week for 4 weeks, KRG was administered to the mice once daily for 4 weeks at doses of 100 or 300 mg/kg, and dexamethasone (DEX, positive control) was administered to the mice once daily for 2 weeks at 3 mg/kg. Results: KRG markedly decreased the macrophage population in bronchoalveolar lavage fluid and reduced emphysematous lesions in the lung tissues. KRG suppressed CSC-induced apoptosis as revealed by terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling staining and Caspase 3 immunohistochemistry. Additionally, KRG effectively inhibited CSC-mediated activation of Bcl-2-associated X protein/Caspase 3 signaling, followed by the induction of cell survival signaling, including vascular endothelial growth factor/phosphoinositide 3-kinase/protein kinase B in vivo and in vitro. The DEX group also showed similar improved results in vivo and in vitro. Conclusion: Taken together, KRG effectively inhibits macrophage-mediated emphysema induced by CSC exposure, possibly via the suppression of pro-apoptotic signaling, which results in cell survival pathway activation. These findings suggest that KRG has therapeutic potential for the prevention of emphysema in COPD patients.