원격 퍼스컴회의 시스템의 다자간 접속을 위한 SAS 구현

崔承鎬,張晟柱,鄭順玉 東新大學校 工業技術硏究所 1997 工業技術硏究 Vol.3 No.-

In this paper, we suggest new MCU to implement multipoint connection in the SAS of remote PC conference systems. The MCU should observe recommendations of H.231 and H.234 of ITU-T. While mixing video data, the number of attendants in limiteded because it decodes bit stream and then encodes again, therefore, multicasting in the application layer should be implemented to solve the limited element. This program implemented the module that enables group manager of SAS and group server to procede and transmit multimedia data. The validity of paper was proved by implementing the function of image rotation that can display all of attentant in SAS of romote PC conference. The main service system is implemented based on Windows NT and Visual C^(++) 2.0.

디지털 이미지 보호를 위한 효과적인 웨이브릿 변환

홍성표,박영옥,송기범,배일호,이준 조선대학교 전자정보통신연구소 2002 電子情報通信硏究所論文誌 Vol.5 No.2

The use of digital imaging technique and digital contents based on internet has grown rapidly for last several years, and the needs of digital image protection become more important. For the purpose of copyright protection on digital image, the verification of authentication techniques like content authentication, ownership authentication, illegal copy and etc are needed. Digital watermarking, the invisible encryption technique to insert digital watermark into image, the sophisticated perceptual information should be used for providing transparency and robustness of images on watermarking process. In this paper, we implement the algorithm for preventing forged attack, ownership protection and authentication by transforming the wavelet algorithms in frequency domain in terms of human visual system.

인터넷 캐쉬를 위한 멀티미디어 데이터의 재배치 정책

홍현옥,임은지,박성호 동의공업대학 2000 論文集 Vol.26 No.1

Through the dramatic growth of Internet, it becomes easy for people to access geographically distributed vast amounts of information. But, currently Internet is suffering from problems such as server overload, network congestion and client response time. In addition, currently the number of continuous media data such as audio and video is growing rapidly. In this paper, we propose SCU(Smallest Caching Utility) proxy caching scheme that stores a portion of continuous media stream or entire stream on the Internet. The proposed scheme reduces client latency and maximizes the amount of data served directly from cache without accessing the central server. By caching the initial fraction of stream data, service startup latency can be reduced. And, by varying the size of the fraction of stream to be cached according to variation of stream popularity, we can utilize the cache space efficiently and maximize the amounts of data served directly from cache. We use the caching utility formula of each stream for the measurement of cache replacement. The way to measure popularity of continuous media stream should be different from that of traditional data such as text and image. We propose the method of measuring popularity of stream using the amounts of data played by clients. We have performed simulations to evaluate our caching policy, Simulation results show that our caching policy outperforms other caching algorithms such as LRU, LFU and SIZE in aspects of BHR(byte hit ratio), initial latency and replacement overhead.

전국 단위 감시체계의 현황과 전망

강성규,안연순,지영구,김형옥,하미나,권호장,백남종,김성아,홍윤철,김재용,강대희,정혜선,하은희 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

이온선 증착 방법에 의한 금속 박막의 물성 연구

손호천,김상옥,조성진 慶星大學校 1999 論文集 Vol.20 No.2

In this paper, the characteristics of metal films such as Al and Cu deposited by thermal evaporation, IBD and ICBD techniques have been studied using XRD, AFM, SEM-EDS. The results show that the initial orientation, the smoothness of these films is improved dramatically by using ion beam methods because of the very slow deposition rate and the adequate surface arrival energy. The deposition rate of the films by IBD and ICBD technique is slower than that of the films by thermal evaporation. And the surface arrival energies of the deposited atoms are from few eV for ICBD to several hundred eV for IBD. These energies are converted to surface migration energies and shallow implantation energies which improve surface qualities.

정전위 SSRT법에 의한 해양구조물용 Cu함유 고장력저합금강의 수소취성한계전위 규명에 관한 연구

김성종,박태원,심인옥,김종호,김영식,문경만 한국해양대학교 해양과학기술연구소 2001 硏究論文集 Vol.10 No.1

A marine structural material was well known to have high tensile strength, good weldability and proper corrosion resistance . Cu-containing high strength low alloy (HSLA) steel was recently developed for their purposes mentioned above, And the steel is free about preheating for welding, therefore it is reported that shipbuilding cost by using it can be saved more or less. However the marine structural materials like Cu-containing HSLA steel are being generally adopted with cathodic protection method in severe corrosive environment like natural sea water but the high strength steel may give rise to Hydrogen Embrittlement due to over protection at high cathodic current density for cathodic protection. In this study, Cu-containing HSLA steel using well for marine atructure was investigated about the susceptibility of Hydrogen Embrittlement as functions of tensile strength, strain ratio, fracture time, and fracture mode, etc. and an optimum cathodic protection potential by slow strain rate test(SSRT) method as well as corrosion properties in natural sea water. And its corrosion resistance was superior to SS400 steel , but Hydrogen Embrittlement susceptibility of Cu-containing HSLA steel was hider than that of SS400 steel. However Hydrogen Embrittlement of its steel by SSRT method was showed with pheonomena such as decreasing of fracture time. strain ratio and fracture mode of QC (quasi-cleavage) Eventually it is suggested that an optimum cathodic protection potential not presenting Hydrogen Embrittlement of Cu-containing of HSLA steel by SSRT method was from-770mV(SCE) to - 900mV(SCE) under natural sea water. (Received September 21, 2000)

응급실 자의퇴원환자의 요인분석

김승환,김옥준,장석준,정구영,김승호 대한응급의학회 1993 대한응급의학회지 Vol.4 No.2

Discharge against medical advice(AMA) in the emergency department is a frustrating, painful event to both patients and emergency physicians and emergency physicians. A retrospective chart review of 347 consecutive AMA patient from our emergency department from December 1992 to May 1993. Among them, 185 patients were interviewed with our researcher about primary cause of AMA through telephone contact. The results were as follows : 1. Total 9,705 patients visited our emergency department during 6-months period and there was 347 AMA patients(3.6%) 2. The main reasons for 185 AMA were ; 1) patients' or family's own problem in 114 cases(61.6%) 2) changes in patient condition(terminal case, improvement) in 56 cases(30.3%). 3) dissatisfaction to medical services in 15 cases(8.1%) 3. During same period, there was 117 cases of drug intoxication mainly due to suicidal attempt and 18 AMA was noted. Among 18 AMA cases, 16 patients discharged against medical advice due to patients' own problem(mainly due to economical problem) but none of them revisited OPD or emergency department. 4. Eight of 40 AMA patients with symptom improvement were managed in OPD, emergency department or other hospital but none of them admitted. In conclusion, we noticed that the main cause of AMA is non-medical problem in Korea and there should be continuous effert to improve our medical insurance system, emergency medical services system. Only through the judicious use of AMA, it can be used as a tool of determining patient satisfaction and quality improvement in emergency medical field.

인체대장암에서의 Cyclin 유전자의 발현

백원기,서민호,서성일,문성희,박종욱,최병길,배옥석 대한대장항문학회 1996 Annals of Coloproctolgy Vol.12 No.2

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

Linear Accelerator를 이용한 Stereotactic Radiosurgery

정상섭,윤도흠,오성훈,김선호,서창옥,추성실,노준규,김동익,서정호 대한신경외과학회 1988 Journal of Korean neurosurgical society Vol.17 No.6

A Modified irradiation technique utilizing a linear accelerator for radiation surgery within the brain was performed in 4 patients. Three of them had brain tumors and one small arteriovenous malformation in midbrain. A Hitchcock stereotactic apparatus and a 10 MeV linear accelerator have been adapted and special computer programs for dosimetry were obtained and studied experimentally with a phantom model. Stereotactic radiosurgery is a valuable tool in the treatment of inoperable, deep seated intracranial lesions, the major advantage being high efficacy and smoothness of the procedure, as well as short hospitalization times.