• 제목/요약/키워드: Presence Service System

검색결과 122건 처리시간 0.025초

Uplink Jamming하에서 OBP 환경을 고려한 군 위성시스템 성능분석에 관한 연구 (Onboard Processing performance under uplink-jamming for military satellite communication systems)

  • 김인겸;신관호;안호성
    • 한국통신학회논문지
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    • 제24권6A호
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    • pp.864-870
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    • 1999
  • 상용위성통신의 경우 일반 광역 통신지원은 가능하지만 전시/유사시의 생존성과 보안성을 요하는 환경에서는 사용이 크게 제한되는 단점이 있다. 따라서, 본 논문은 군 위성시스템에 적용 가능한 세 가지 형태의 중계시스템을 제안하고 분석했으며, 상향링크 방해시의 지원 가능한 데이터율을 기준으로 성능을 분석/비교하여 군 운용환경에 따른 위성자원의 이용효율을 높이는 방안을 모색하였다. 이를 이해 중계기와 함정용 단말의 설계변수를 설정하여 적용하였으며, 또한, 각 대역별(UHF/SHF/EHF) 항방해 성능비교를 통하여 운용환경에 따른 생존성의 정도를 파악하였다.

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VoIP서비스의 스팸 공격에 대한 차단 연구 (A Study of Interception for a Spam Attack of VoIP Service)

  • 이인희;박대우
    • 한국컴퓨터정보학회논문지
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    • 제11권5호
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    • pp.241-250
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    • 2006
  • 본 논문에서는 VoIP서비스의 취약점 중에서 파급 효과가 가장 큰 스팸공격과 차단에 대한 연구를 하였다. VoIP 서비스에 대한 스팸공격의 시나리오를 작성하고, 콜 스팸, 인스턴트 메시징 스팸, 프레즌스 스팸 공격을 실시한다. 실험실에서 스팸 공격이 성공됨을 증명하고, 사용자의 피해 사실을 확인한다. VoIP서비스의 스팸 차단 방법의 제안에서 1) 인바이트 리퀘스트 플루드 공격의 차단 2) 블랙/화이트 리스트, 3) 역추적, 4) Black Hole-Sink Hole, 5) 콘텐츠 필터링, 6) 동의 기반 통신, 7) 콜 행위 패턴 조사, 8) 레퓨테이션 시스템을 제안하고 실험한다. 각각의 제안된 차단 방안을 VoIP 네트워크에서 실험하여 스팸차단의 보안 등급을 확인한다. 본 논문의 연구결과를 통하여 VoIP 서비스의 정보보호가 WiBro, BcN에서 확대되어 유비쿼터스 보안을 실현하는데 이바지 할 수 있도록 하겠다.

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On-off controllable RNA hybrid expression vector for yeast three-hybrid system

  • Bak, Geunu;Hwang, Se-Won;Ko, Ye-Rim;Lee, Jung-Min;Kim, Young-Mi;Kim, Kyung-Hwan;Hong, Soon-Kang;Lee, Young-Hoon
    • BMB Reports
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    • 제43권2호
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    • pp.110-114
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    • 2010
  • The yeast three-hybrid system (Y3H), a powerful method for identifying RNA-binding proteins, still suffers from many false positives, due mostly to RNA-independent interactions. In this study, we attempted to efficiently identify false positives by introducing a tetracycline operator (tetO) motif into the RPR1 promoter of an RNA hybrid expression vector. We successfully developed a tight tetracycline-regulatable RPR1 promoter variant containing a single tetO motif between the transcription start site and the A-box sequence of the RPR1 promoter. Expression from this tetracycline-regulatable RPR1 promoter in the presence of tetracycline-response transcription activator (tTA) was positively controlled by doxycycline (Dox), a derivative of tetracycline. This on-off control runs opposite to the general knowledge that Dox negatively regulates tTA. This positively controlled RPR1 promoter system can therefore efficiently eliminate RNA-independent false positives commonly observed in the Y3H system by directly monitoring RNA hybrid expression.

조기퇴원 수술환자의 병원중심 가정간호 효과 및 비용분석에 관한 연구 (A Study on Effectiveness of the Hospital-based Home Nursing Care of the Early Discharged Surgical Patients and its Cost Analysis)

  • 박경숙;정연강
    • 대한간호학회지
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    • 제24권4호
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    • pp.545-556
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    • 1994
  • Medical insurance and health care delivery system enabled Korean people to get the necessary medical service, but it caused increased needs for medical service, and resulted in the occurence of some problems such as a lack of manpower and medical facilities. In order to solve these problems, many countries, which already had medical insurance system had developed home care system and it has been regarded effective both in reducing costs and in increasing the rates of turnover of bed. Recently, Korea has included home nursing care in its health care delivery system, and some models of the hospital based home nursing care had been tried and its effects had been evaluated. So, author tried to run a home nursing care for the Cesarean section mothers and evaluate Its effects both in the mother's health and costs. This study was designed as a Quasi-experimental study. Subjects were thirty mothers who got Cesarean section operation in hospital in Seoul. Experimental group consisted of 15 volunteers, and control group were selected by means of matching technique. Data were gathered from February 1st to March 26th by two assistants who were trained by author. Experimental group were discharged on the 4th day after their operation, and got nursing care and assessment about their home three times on the 5th, 6th, and 7th day. Control group stayed in the hospital until 7th day as usual and were checked on the same day as above mentioned To evaluate the state of physiological recovery, vital signs, H.O.F, presence of edema in the legs, bathing, appetite, sleep, presence of pain or discomfort in the breasts, amount of lochia, color of lochia, defecation urination. To compare incidence of complication in experimental group with that in control group, specific assessment was done such variables as smell of lochia, presence of inflammation of operation wound, dizziness, and presence of immobilization in the extremities. The activities of daily living were checked Satisfaction of nursing were checked To calculate costs, author asked subjects to specify expenditure including hospital charge, traffic enpenses, and food expenses. The results were as fellows. 1. On effectiveness of home nursing careThere were n significant differences between experimental and control group in incidence of abnormal symptoms and any complication. The number of taking a bath [POD #5 P=0.001, #6 P=0.0003, #7 P=0.001] and the degree of appetite [POD #5 P=0.03, #6 P=0.02, #7 P=0.013] were significantly higher in experimental group than in control group. Contrary to author's expectation, the degree of the activities of daily living in experimental group was not higher than that of control group. All of the experimental group said they were satisfied with the home nursing care. 2. Cost analysis 1) Hospital charge of experimental group was lower than that of control group. [P=0.009] By taking home nursing care, average period of hospitalization was shortened to 3.1 days, and family members could save 22.8 hours. Total amount of money saved by early discharge was 3,443,093 Won. It is estimated that total amount of money saved by early discharge in a year will be 40,398,956 Won. 2) Home nursing care charge of 15 mothers was 1,781,633 Won. It is estimated that total amount of money Saved by it in a year Will be 20,904,493 Won. It was lower altogether than hospital charge of the three days which is 5th, 6th, 7th day of operation. The average cost of single home visit was calculated 10,940 Won. It took 87 minutes per round and it costed 1,017.3 Won. The average hour of home care was 39.0 minutes. 3) It is expected that early discharge can bring forth the increase of hospital income. On the condition that the rate of running bed is 100%, the expected increase of hospital income will be 202,374, 026 Won in a year. Suggestions for further study and nursing practice are as follows : 1. For the welfare of patients and the increased rates of running bed, home nursing care system should be included in the hospital nursing care system. 2. Studies to test effect of home nursing care on the patients with other diseases are needed. 3. Establishment of law on the practice of home nursing care is strongly recommended.

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GPS 전리층 모델의 장기간 가용성 및 정확도 변화 분석 (Long-term Analysis of Availability and Accuracy Variation of GPS Ionospheric Delay Model)

  • 김정래;김용래
    • 한국항행학회논문지
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    • 제27권6호
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    • pp.841-848
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    • 2023
  • 위성 항법 장치 (GPS; global positioning system) 항법메시지에 포함된 Klobuchar 전리층모델은 L1 단주파수 사용자들에게 전리층 보정정보를 제공한다. 전리층모델 정확도는 항법해의 정확도에 큰영향을 끼치므로 이에 관한 분석이 필요하다. 본 연구에서는 1993년부터 2022년까지의 GPS 항법메시지를 조사하여 Klobuchar 모델의정확도 및 계수 존재 여부와 효용성 여부를 분석 하였다. 초기 GPS 항법메시지의 경우 전리층데이터를 포함하지 않는 경우가 많으며, 전리층모델을 포함되어 있더라도 정확도가 상당히 낮은 경우가 많이 존재하였다. 전리층모델의 정확도가 안정화된 2002년부터 2022년까지 전리층모델의 정확도 변화와 지자기 위도에 따른 정확도 차이를 IGS (International GNSS Service)에서 제공하는 전리층모델과 비교하는 방법으로 분석하였다.

실내 무선 페이딩 채널 환경에서 임펄스성 전자간섭파에 의한 GFSK시스템의 성능 분석 (Performance Analysis of GFSK Systems by Impulsive Electromagnetic Noise in Indoor Radio Fading Channel Environment)

  • 이양선;김지웅;강희조
    • 한국전자파학회논문지
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    • 제12권7호
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    • pp.1115-1121
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    • 2001
  • 본 논문에서는 실내 무선 통신 환경에서 발생하는 페이딩 현상과 전자기기에서 방출되는 임펄스성 전자간섭 파에 따른 GFSK 시스템의 성능을 분석하고 데이터 전송 서비스를 만족하기 위하여 성능 보상 방안으로 Truncated Type-II Hybrid ARQ 기법을 적용하여 열화된 시스템의 성능을 개선하였다. 결과에 의하면, 페이딩과 임펄스성 전자간섭파에 의해 시스템에 심각한 영향을 미치게 되는데 특히, 직접파 성분이 존재하는 페이딩 보다는 임펄스성 전자간섭파의 발생빈도와 크기에 따라 시스템 성능이 크게 좌우됨을 알 수 있었다. 성능 개선책으로 Truncated Type-II Hybrid ARQ 기법을 채용함으로써 낮은 신호전력(20 dB)에서도 향상된 성능 개선을 얻을 수 있었고, error floor 구간이 형성되고 시스템에 영향을 크게 미치는 강한 임펄스성 전자간섭파 환경에서도 24 dB 이상에서 성능 개선을 얻을 수 있었다.

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센서 기반 사용자 상태 인식 알고리즘을 이용한 저전력 서비스에 관한 연구 (Study on the Low Power Service with User State Recognition Algorithm Using Sensors)

  • 이도경;홍원기;차경애
    • 대한임베디드공학회논문지
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    • 제10권2호
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    • pp.91-99
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    • 2015
  • The electric power consumed by the embedded devices has become a critical issue because the reduction of power consumption is an important factor to prolong the battery-operated devices' lifetime. Many researches and techniques to reduce the power consumption have been proposed and developed but any power method cannot guarantee optimal power consumption of an embedded device - it would be faced with numerous situation - in all ways. Specifically, power researches for embedded devices deployed in the industry field have hardly been done. In this paper, low power service is proposed to minimize power reduction with the several usage status of embedded devices in the industry field. The usage status is basically classified according to the distance between the device and the user which is obtained by the ultrasonic and PIR sensor. The performance evaluation shows that the proposed scheme can reduce the power consumption by up to 45.3% compared to the device with no power reduction scheme. It also shows that the power consumption of the proposed scheme is 5.2% ~ 16.8% lower than that of the timeout scheme.

Eimeriosis in Korean indigenous calves with bloody diarrhea from March, 2006 to March, 2007

  • Chon, Seung-Ki;Lee, Han-Kyung;Song, Hee-Jong
    • 한국동물위생학회지
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    • 제30권2호
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    • pp.269-274
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    • 2007
  • The aim of this study was to examine the epidemiological features of Eimeria in calves with acute diarrhea. Samples were collected from between 15 days and 90 days old calves (n=83) in Gimje area from March 2006 to March 2007. Feces of bloody diarrhea were examined for the presence of Eimeria oocysts using a sucrose flotation method. Out of 83 calves, 62 (74.6%) had Eimeria oocysts. In the results of monthly analysis, the highest prevalence (12.0%) of Eimeria oocysts was found on June. In the seasonal infection rate, spring was the highest prevalence (30.1%), followed by summer (24.0%). Furthermore, the highest prevalence (44.5%) was found in calves from between 31 - 60 days old in the analysis by ages. However, there was no significant differences between female and male sex even though the prevalence was slightly bigger in female than in male. The prevalence of the present study to detect Eimria oocysts for infection may have been affected by weather-conditions in the spring. Young calves should be separated to minimize the infection from cattle as much as possible. Additional studies are necessary to find other factors for infection and combining molecular methods with a highly sensitive system for Eimeria detection could be a reliable and economic way of Eimeria eradication.

An Educational Service Platform using Collective Intelligence and Presence of Web 2.0

  • Kim, Chang-Suk;Son, Dong-Cheul;Cho, Chung-Ho
    • 한국지능시스템학회논문지
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    • 제19권1호
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    • pp.115-121
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    • 2009
  • Web 2.0 has become the face next generation Web among the business world and research community. Web 2.0 is instant superficial gratification of people. On the other hand, Semantic Web is deep, meaningful and lasting relationship with data. So, it is difficult to apply the Semantic Web to the real world. In this paper, a platform for educational services using the Semantic Web and Web 2.0 is proposed. The proposed platform is based mix of the Semantic Web and Web 2.0, so it is useful to apply in the real world applications. Two services are presented, one is a semantic email system and the other is a cyber study space. The cyber study space adjusted each student is presented. The study environment is called iStudySpace that has personal scheduler, study status plan table, personalized search engine and several gadgets. Finally characteristics and limitations of the Semantic Web and Web 2.0, the organization and components of the platform, evaluation of iStudySpace are shown.

PSK 고차모드 위성전송을 위한 저잡음 증폭 주파수 변환기의 위상 잡음 해석 (Phase Noise Spectrum of LNB for PSK Multi-mode satellite transmission signal)

  • 김영완
    • 한국정보통신학회논문지
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    • 제12권7호
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    • pp.1180-1186
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    • 2008
  • 본 논문에서는 고속 데이터 전송을 위한 고차 모드 신호의 양호한 위성 전송에 요구되는 수신 단말기의 저잡음 증폭 주파수 변환기의 위상 잡음 특성을 해석한다. 위상 잡음은 낮은 데이터 전송뿐만 아니라 고속 데이터 전송을 위한 고차 모드 신호 전송에 심각한 영향을 미치며, 전송 링크 주파수가 증가함에 따라 위상 잡음이 증가하여 고속 데이터 전송에 요구되는 고차 모드와 높은 주파수 사용으로 인한 전송 열화 성능은 증가한다. 따라서, 높은 주파수 영역을 갖는 고차 모드 수신 단말기의 저잡음 증폭 주파수 변환기의 위상 잡음은 전송 성능에 지배적인 영향을 가지므로, 저잡음 증폭 주파수 변환기 위상 잡음에 대한 가용 전송 모드를 해석하고 가용 서비스 적용 방법을 제시한다.