신장이식 환자에서 HCMV 항원혈증 검사의 임상적 유용성

김탁,성흥섭,박관태,김송철,김성한,최상호,김양수,우준희,박수길,한덕종,이상오 대한감염학회 2009 감염과 화학요법 Vol.41 No.2

Background : This study was performed to determine the cut-off value and the predictability of symptomatic human cytomegalovirus (HCMV) infection according to the peak value of HCMV antigenemia assay in kidney transplant recipients. Materials and Methods : We reviewed the results of HCMV antigenemia assay (Chemicon, CA, USA) in patients who received kidney transplantation at our institution from May 2003 through May 2008, and investigated the existence and the type of HCMV infection by the medical record review. Patients who underwent the test only once during the episode or those who received ganciclovir for more than 48hrs before the test were excluded. The receiver-operator characteristic curve was drawn and the point showing maximum likelihood ratio (LR) was chosen as the cut-off value of symptomatic HCMV infection. Results : A total of 689 episodes were screened and 134 episodes were enrolled. Thirty-three (24.6%) episodes were symptomatic HCMV infection, 23 (17.2%) episodes were associated with HCMV syndrome, and 10 (7.5%) episodes were tissue-invasive diseases. The maximum LR was 7.5 (95% confidence interval, 4.014.2) and the cut-off value was 29.5 cells/200,000 WBC. The sensitivity, specificity, Positive predictive value, and negative predictive value were 66.7%, 91.1%, 71.0%, and 89.3%, respectively. Conclusions : The cut-off value of symptomatic HCMV infection by the peak value of HCMV antigenemia assay in our study was similar with previous results, although the sensitivity was relatively low.

조혈모세포이식 환자에서 침습성 진균 감염에 대한 Micafungin의 예방 효과 및 안전성

김시현,이동건,최수미,권재철,박선희,최정현,유진홍,이성은,조병식,김유진,이석,김희제,민창기,조석구,김동욱,이종욱,민우성,박종원 대한감염학회 2010 감염과 화학요법 Vol.42 No.3

Background: Micafungin, a potent inhibitor of 1,3-β-D-glucan synthase, is a novel antifungal agent of the echinocandin class. In vitro study showed that micafungin was effective against Aspergillus species as well as Candida species, but clinical data on the prophylactic efficacy against invasive fungal infections (IFIs) other than candidiasis are still lacking. Materials and Methods: We identified 60 consecutive adult hematopoietic stem cell transplantation (HSCT) recipients who received at least 3 doses of micafungin during neutropenic period. Micafungin was started as an alternative in patients who were intolerant or had adverse events (AEs) to primary prophylactic antifungal agents. We retrospectively reviewed the medical records and analyzed the efficacy and safety of micafungin for prophylaxis against IFIs. Results: The patients either had autologous (n=9) or allogeneic (n=51: 1 syngeneic, 24 sibling, 26 unrelated donor) HSCT. Itraconazole oral solution (n=58) was the most frequently used first line antifungal agent for prophylaxis and was administered for median 11 days. The most frequent cause of switch to micafungin was vomiting (n=42). The duration of neutropenia and micafungin administration was median 13 and 12 days, respectively. A successful outcome was achieved in 45 (75%) patients. Empirical antifungal therapy was initiated in 13 (22%) patients. There were 2 cases (3.3%) of breakthrough fungal infections which comprised a probable invasive pulmonary aspergillosis and a possible invasive fungal sinusitis. There was no case of invasive candidiasis. A total of 53 (88%) patients experienced at least one AE regardless of causality during micafungin administration. The most frequent AEs were hypokalemia, vomiting, diarrhea, and elevated serum aspartate aminotransferase or alanine aminotransferase. Among the aforementioned AEs, only 1 case of diarrhea could be classified as a probable relation with micafungin when causality was assessed. There was no AEs that caused discontinuation of micafungin. Conclusions: Micafungin seems to be a safe and effective agent for prophylaxis of IFIs including aspergillosis as well as candidiasis in HSCT recipients. However, further large, prospective, and randomized comparative studies are warranted for aspergillosis.

랜덤 키 분할을 이용한 모바일 RFID 사용자의 프라이버시를 보호하는 상호 인증 프로토콜

정윤수(Yoon-Su Jeong),김용태(Yong-Tae Kim),박길철(Gil-Cheol Park),이상호(Sang-Ho Lee) 한국통신학회 2011 韓國通信學會論文誌 Vol.34 No.9

이동 통신망에 RFID 기술을 접목한 모바일 RFID는 사용자 자신이 휴대한 휴대전화로 제품에 부착된 RFID태그의 식별자를 읽고, 이 식별자를 이동통신망을 통해 네트워크로 전달하여 제품에 대한 정보를 얻는 기술이다. 그러나 모바일 RFID는 기존 RFID에서 요구되어지는 보안 요구사항 중 프라이버시 문제가 여전히 존재하는 문제점이 있다. 이 논문에서는 모바일 RFID 사용자가 태그 정보를 백 엔드 서버로부터 안전하게 전달받기 위해서 초기화 과정과 상호 인증과정에서 모바일 RFID 리더와 태그가 생성한 랜덤키를 임의의 크기로 분할하여 프라이버시 보호가 필요한 태그에 대해서 모바일 RFID 리더가 매 세션마다 난수생성기에 의해 항상 다른 하부키 값을 생성함으로써 태그의 어떤 정보도 제 3자에게 제공하지 않도록 하고 있다. 성능 평가 결과 제안 프로토콜은 등록 계산량과 로그인 계산량에서 모듈러 연산을 사용하는 기존 프로토콜과 달리 일방향 해쉬 함수를 사용하여 사용자의 정보를 등록하기 때문에 MARP 기법<SUP>[7]</SUP>과 Kim 등의 기법<SUP>[12]</SUP>보다 저장 공간과 계산량에서 효율성이 높았다. Mobile RFID which integrates mobile network with RFID technique is the technique to get the information of products by transmitting the identifier through mobile network after reading the identifier of RFID tag. It attached on the equipment as the mobile phone. However, mobile RFID has the privacy-related problem among requested secure problems required from the existing RFID. In this paper, the random key created by mobile RFID reader and Tag during the inter-certificating and initialization procedure for mobile RFID users to receive tag information from backend server securely is divided into random sizes and any information on the tag which requires the protection of privacy shouldn't be provided to anyone. In performance analysis, previous protocol used modulo operation in registration and login computation. But the proposed protocol has higher efficiency in saving space and computation volume than MARP scheme<SUP>[7]</SUP> and Kim. et. al<SUP>[12]</SUP> scheme because our protocol is accomplished by mutual authentication and registering user information through one-way hash function.

시각 암호화와 가상 위상 영상을 이용한 광학적 보안 시스템

김철수 경주대학교 2003 論文集 Vol.16 No.-

In this paper, we proposed an optical security system using visual cryptography and virtual phase images. In encryption process, original image is shared out virtual image, random iamge, and decryption key image, and they are phase modulated. We multiply the phase virtual image with the phase random image, and then multiply with each complex image which has its magnitude with constant value. Finally, the encryption cards are made by Fourier transforming the multiplicated images. It is possible to protect information of the orignal image because the cards have not any information of the original image. To reconstruct the original image from the encrypted card images, Encrypted card images are put on the paths of Mach-Zehnder interferometer to be summed the card images. The summed image is inverse Fourier transformed by Fourier lens, and multiplied with phase decryption key and then interferenced with reference beam again. Finally, the original image is recovered in the form of intensity on the CCD plane. Computer simulations show a good performance of the proposed optical security system.

광 형태학을 이용한 자동차 번호판의 숫자 추출

김철수 경주대학교 건설환경연구소 2000 建設環境論叢 Vol.- No.3

A new method for detection of an automobile registration plate using optical morphology is proposed. In this method, we recognize corners of an automobile registration plate and detect it. First of all, we design optimal structuring elements for corner recognition and they are applied to optical rank order HNT(Hit Miss Transform). Optical rank order HMT gives better performance than standard HMT in random noises and cluttered image. In the case of automobile registration plate with noise, we eliminated it by opening and closing. The computer simulation and optical experiment show that proposed method has good capability of detecting automobile registration plate.

실시간 운영 체제

金哲秀,河蘭,金鎭午 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.2

Process management and synchronization, memory management, interprocess communication, and I/O are main functional areas that Operating Systems should support. Real-time Operating Systems provide these features in specific ways because they have different requirements from Non Real-time Operating Systems. In particular, real-time operating systems focus on predictability and include features to support time constraints. Three general categories of real-time operating systems are: small and proprietary kernels(which are commercially available as well as homegrown kernels), realtime extensions to commercial timesharing operating systems such as UNIX, and research kernels. In this paper we survey these three main categories of real-time operating systems.

새로운 각도 다중화 방법을 이용한 홀로그래픽 광메모리 시스템의 구현과 응용

金喆洙 경주대학교 1998 論文集 Vol.10 No.-

It is proposed that an holographic optical memory system for image storage in BaTiO_3 crystal using new angular multiplexing method which controls the incident angle of reference beam electrically. In the new angular multiplexing method, the incident angle of the reference beam is controlled by using BPH(binary phase hologram), which is designed and optimized with SA(simulated annealing) algorithm and represented on LCTV(liquid crystal television) for real-time processing. The reference beam can be generated anywhere in two dimensional planes by Fourier transform of the BPH on the LCTV which is controlled by a computer. So, the vertical and horizontal incident angle of the reference beam on the BaTiO_3 can be controlled simultaneously. Thus the proposed holographic optical memory system is simple and stable because there is no mechanical movement in storage and reconstruction process of the images. By using the proposed system, we demonstrated storage and reconstruction experiments for four binary images. We also demonstrated an application experiment that can acquire large number of images than that of the stored images by controlling the number of reference beams. Through this experiment, the proposed holographic optical memory system is expected to be used in the realization of the weighted optical interconnections for optical computing and communications.

유기용제 취급근로자들의 요중대사물질과 말초임파구 자매염색분체교환 발현빈도에 관한 조사연구

김돈균,황인경,류철인,이수일,정갑열,이용환,이충렬,현원일,김석봉,전용덕 大韓産業醫學會 1990 대한직업환경의학회지 Vol.2 No.1

저자들은 유기용제 취급여성근로자 90명을 대상으로 1988년 7월부터 1989년 8월까지 말초혈액임파구에서의 자매염색분체교환의 발현빈도를 조사하고 이들의 업종, 근속연수, 요중마뇨산 농도등이 자매염색분체교환의 발현빈도에 미치는 영향을 조사하였으며 그 결과를 요약하면 다음과 같다. 1. 유기용제 취급근로자들의 말초혈액임파구에서의 자매염색분체교환의 발현빈도는 대조군에 비하여 유의하게 증가되었다. 2. 말초혈액임파구에서의 자매염색분체교환의 발현빈도가 가장 높은 업종은 프라스틱제품 제조업이었다. 3. 근속연수가 말초혈액임파구에서의 자매염색분체교환의 발현빈도에 미치는 영향은 현저하지 않았다. 4. 요중마뇨산농도와 말초혈액임파구에서의 자매염색분체교환의 발현빈도간에는 유의한 상관관계가 있었다. In order to know the possibility of utilizing the sister chromatid exchanges as an index which could evaluate the effect of organic solvents on the health in industrial workers, the authors studied the effects of the inductivity of sister chromatid exchanges in peripheral lymphocytes from 90 female workers expoxed to organic solvents and 20 non-exposed female workers. The results obtained were as follows : 1. The frequency of sister chromatid exchanges in peripheral lymphocytes from 90 female workers exposed to organic solvents was significantly increased in comparison with 20 control subject. 2. The frequency of sister chromatid exchanges was significantly increased in the workers who were employed in the manufacture of plastic materials than the other manufactures. 3. There were no significant differences in the frequency of sister chromatid exchanges by carriers of the exposed workers.

편광과 위상 홀로그램을nmmmm 이용한 정보보호 시스템의 구현

김철수 경주대학교 2001 論文集 Vol.14 No.-

This thesis presents an interferometer-based optical information security system that can produce a stable decrypted image regardless of a change in the optical path length. Interference noise is a serious problem in an interferometer, because it can result in the vibration of the output image. In the proposed system, a polarizing beam splitter is substituted for the beam splitter in a Mach-Zehnder interferometer. As a result, two lights on each path are perpendicularly polarized to each other in the interferometer. Since the incoherence of the two perpendicularly polarized lights removes any interference noise, the decrypted image is stable. Accordingly, the decrypted image of the proposed system can be used as the input for another optical system, regardless of any external change in the optical path length. To encrypt an image, the original image is divided into two intensity images. Encrypted phase images are then obtained from these two images in various ways, including randomly diffusing pixels, randomly removing pixels, or the use of SA algorithm. The use of phase holograms prevents the copying of encrypted images with intensity detectors. The proposed process of encryption and decryption was computer simulated and optically evaluated, and it was verified that the proposed system can produce a stable decrypted image.

반복 알고리듬에 근거한 광 상관기를 이용한 영상 보안 시스템

김철수 경주대학교 정보전자기술연구소 2003 情報電子技術論叢 Vol.2 No.-

In this paper, a practical image security system using 4-f Optical Correlator based on the SA algorithm is proposed. In the encrypting process, we would generate encrypted image and key image with binary phase components using iterative SA algorithm. In the decrypting process, we can get a correlation results of the encrypted and key images using 4-f correlator system. In the proposed method, the encrypted and key images consisted of binary phase components. So, it is easy to implement optical security system using the proposed technique. And if we fix the encrypted image in the optical security system and change the key image, we get different images, so it is possible to apply to the distinguished authorization system using different key images. Computer simulations show that despite the binary phase components, the quality of the decrypted images are very good in terms of mean squared error.