• 제목/요약/키워드: high availability

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스마트폰을 이용한 원격 물리적 보안 시스템의 구현 (Implementation of Remote Physical Security Systems Using Smart Phone)

  • 이문구
    • 한국컴퓨터정보학회논문지
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    • 제16권2호
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    • pp.217-224
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    • 2011
  • 기존의 유선상의 물리적 보안 시스템은 시간적, 공간적 제약을 갖는다. 이러한 문제점을 해결하기 위해서 본 연구는 스마트폰을 이용한 원격 물리적 보안 시스템을 구현 하였으며, 연구는 모바일 클라우드 컴퓨팅 기술을 기반으로 구현되었다. 모바일 클라우드 컴퓨팅 기술에서 요구되는 사용자 인증, 통신의 비밀성, 정보의 무결성, 시스템의 가용성, 접근제어 및 권한관리 그리고 안전한 핸드오프 등의 보안 기술을 구현하였다. 구현된 시스템은 계측, 감시, 제어를 통한 에너지 비용 절감 (5~30%)의 효율성을 갖는다. 본 시스템의 평균 접속 및 응답 시간 측정결과 값도 약 7.082초 이내로서 성능 대비 효율성이 높은 것으로 평가된다.

하이브리드 다자유도 시스템의 틸팅 구동용 토크액츄에이터 설계 (Design of Torque Actuator in Hybrid Multi-D.O.F. System)

  • 홍현석;박현종;원성홍;김솔;이주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2015년도 제46회 하계학술대회
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    • pp.665-666
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    • 2015
  • In this paper, it is proposed to substitute the tilting operation device of hybrid multi-D.O.F system from three phase SPM to single phase torque actuator. When using tilting operation with three phase SPM which is appropriate for continuous rotary operation, there are disadvantages that electricity availability rate is low and controllability is difficult. On the other hand when using a single phase torque actuator instead of SPM, it is appropriate for sequential tilting, electricity availability rate is high, and it is easy to control. Thus this will have a great influence on the development and practical use of the system. This study designed a single phase torque actuator in consideration of the magnetic saturation. Also, this was verified with comparative analysis with SPM through FEM(finite element method) analysis values of the design model and test values of the manufactured model.

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RELATIONSHIP BETWEEN SOME CIRCULATING HORMONES, METABOLITES AND MILK YIELD IN LACTATING CROSSBRED COWS AND BUFFALOES

  • Jindal, S.K.;Ludri, R.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제7권2호
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    • pp.239-248
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    • 1994
  • To study the relationship between certain hormones and metabolites and between hormones and milk yield during different stage of lactation, six lactating Karan Swiss cows and six Murrah buffaloes were maintained. Growth hormone, insulin, $T_3$, $T_4$, glucose, BHBA, NEFA and milk yield were studied. Highly negative relationship of growth hormone with insulin and triiodothyronine in cows and marginally negative in buffaloes suggest that insulin and triiodothyronine aid in the process of partitioning of nutrients towards milk production through reducing the demands of nutrients by peripheral tissue. The significant and negative correlation of growth hormone with dry matter intake in both the species suggest that the availability of nutrients from the digestive tract play a role in the regulation of growth hormone secretion. Positive relationship of growth hormone with non esterified fatty acids in both the species suggest that high growth hormone levels may result in fat mobilization and thereby increase the availability of energy precursors for milk synthesis. Insulin was negatively correlated with milk yield and lactose content and positively with milk fat and protein but the degree of relationship varied. In both the species the relationship between triiodothyronine and milk yield was negative and between thyroxine and milk yield was positive. However, it was significant only in cows and not in buffaloes. Thyroxine was positively correlated with beta-hydroxybutyrate and non-esterified fatty acids with milk yield in both the species.

소프트웨어 재활기법에 기반한 주-여분 서버 시스템의 작업전이 시간 분석 (Switchover Time Analysis of Primary-Backup Server Systems Based on Software Rejuvenation)

  • 이재성;박기진;김성수
    • 정보처리학회논문지A
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    • 제8A권2호
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    • pp.81-90
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    • 2001
  • 인터넷의 급속한 확산으로 인하여, 컴퓨터 시스템의 규모 및 복잡도가 점차 증가하고 있으며, 컴퓨터 시스템에 대한 높은 수준의 가용도 요구 조건을 충족시키기 위해, 하드웨어적.소프트웨어적 결함 허용 기법에 대한 연구가 활발하다. 소프트웨어 재활 기법은 서버에 탑재된 소프트웨어의 장시간 가동에 따른 소프트웨어 노화 현상을 다루고 있으며, 서버에서 실행중인 소프트웨어의 수행을 고의적으로 멈춘 후에 결함 발생 가능성이 낮은 초기 상태에서 이를 다시 가동시키는 소프트웨어적 결함 예방 방법의 일종이라 볼 수 있다. 본 연구에서는 주-여분 서버 시스템에서의 작업전이 시간이 소프트웨어 재활에 미치는 영향을 연구하였으며, 가용도 분석을 통해서 작업전이 시간이 재활 정책을 결정함에 있어서 중요한 요소임을 발견하였다.

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하지 강직 평가에 있어 NK테이블을 이용한 진자검사의 유용성 (Availability of the Pendulum Test Using NK Table for Spasticity Measurement of Low Extremity)

  • 김용욱;원종혁;김태호
    • 대한물리의학회지
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    • 제8권2호
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    • pp.209-217
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    • 2013
  • PURPOSE: The purpose of this study was to investigate the clinical availability of the pendulum test (through reliability and validity) using a NK table attached electrogoniometer for spasticity measurement in patients with brain lesions. METHODS: Thirty-one stroke and traumatic brain injury subjects participated in the study. Intraclass correlation coefficient (ICC) was used to verify the test-retest reliability of spasticity measures of the pendulum test. Pearson's product correlation coefficient was used to examine the validity of the pendulum test through the amplitude of the deep tendon reflex (DTR) test known for objective and quantitative measure of spasticity. RESULTS: In these results, the test-retest reliability was showed significantly high correlation between pendulum tests (ICCs=.95~.97, p<.01). There were significant negative correlations between the amplitude of the DTR test and all measures of spasticity of the pendulum test(r=-.77~-.85, p<.01). CONCLUSION: Thus, it is possible to use the pendulum test using a NK table as an objective measure of spasticity, rather than other expensive equipment, which is more complicated to use. Further studies are needed to explore the therapeutic effects of spasticity using a newly designed pendulum test equipment in this study.

MEASUREMENT AND SIMULATION OF EQUATORIAL IONOSPHERIC PLASMA BUBBLES TO ASSESS THEIR IMPACT ON GNSS PERFORMANCE

  • Tsujii, Toshiaki;Fujiwara, Takeshi;Kubota, Tetsunari;Satirapod, Chalermchon;Supnithi, Pornchai;Tsugawa, Takuya;Lee, Hungkyu
    • 한국측량학회지
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    • 제30권6_2호
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    • pp.607-613
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    • 2012
  • Ionospheric anomaly is one of the major error sources which deteriorate the GNSS performance. In the equatorial region, effects of the ionospheric plasma bubbles are of great interest because they are pretty common phenomena, especially in the period of the high solar activity. In order to evaluate the GNSS performance under circumstance of the bubbles, an ionospheric scintillation monitor has been developed and installed in Bangkok, Thailand. Furthermore, a model simulating the ionospheric delay and scintillation due to the bubbles has been developed. Based on these developments, the effects of the simulated plasma bubbles are analyzed and their agreement with the real observation is demonstrated. An availability degradation of the GPS ground based augmentation system (GBAS) caused by the bubbles is exampled in details. Finally, an integrated GPS/INS approach based on the Doppler frequency is proposed to remedy the deterioration.

나셀 라이다 측정 데이터 특성 분석 및 신뢰성 검증 (Characteristics Analysis and Reliability Verification of Nacelle Lidar Measurements)

  • 신동헌;고경남;강민상
    • 한국태양에너지학회 논문집
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    • 제37권5호
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    • pp.1-11
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    • 2017
  • A study on Nacelle Lidar (Light detection and ranging) measurement error and the data reliability verification was carried out at Haengwon wind farm on Jeju Island. For measurement data error processing, the characteristics of Nacelle Lidar measurements were analyzed by dividing into three parts, which are weather conditions (temperature, humidity, atmosphere, amount of precipitation), mechanical movement (rotation of wind turbine blades, tilt variation of Nacelle Lidar) and Nacelle Lidar data availability. After processing the measurement error, the reliability of Nacelle Lidar data was assessed by comparing with wind data by an anemometer on a met mast, which is located at a distance of 200m from the wind turbine with Nacelle Lidar. As a result, various weather conditions and mechanical movement did not disturb reliable data measurement. Nacelle Lidar data with availability of 95% or more could be used for checking Nacelle Lidar wind data reliability. The reliability of Nacelle Lidar data was very high with regression coefficient of 98% and coefficient of determination of 97%.

Interaction at the nanoscale of fundamental biological molecules with minerals

  • Valdre, Giovanni;Moro, Daniele;Ulian, Gianfranco
    • Advances in nano research
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    • 제1권3호
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    • pp.133-151
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    • 2013
  • The availability of advanced nanotechnological methodologies (experimental and theoretical) has widened the investigation of biological/organic matter in interaction with substrates. Minerals are good candidates as substrates because they may present a wide variety of physico-chemical properties and surface nanostructures that can be used to actively condense and manipulate the biomolecules. Scanning Probe Microscopy (SPM) is one of the best suited techniques used to investigate at a single molecule level the surface interactions. In addition, the recent availability of high performance computing has increased the possibility to study quantum mechanically the interaction phenomena extending the number of atoms involved in the simulation. In the present paper, firstly we will briefly introduce new SPM technological developments and applications to investigate mineral surfaces and mineral-biomolecule interaction, then we will present results on the specific RNA-mineral interaction and recent basics and applicative achievements in the field of the interactions between other fundamental biological molecules and mineral surfaces from both an experimental and theoretical point of view.

Architectures and Connection Probabilities forWireless Ad Hoc and Hybrid Communication Networks

  • Chen, Jeng-Hong;Lindsey, William C.
    • Journal of Communications and Networks
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    • 제4권3호
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    • pp.161-169
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    • 2002
  • Ad hoc wireless networks involving large populations of scattered communication nodes will play a key role in the development of low power, high capacity, interactive, multimedia communication networks. Such networks must support arbitrary network connections and provide coverage anywhere and anytime. This paper partitions such arbitrarily connected network architectures into three distinct groups, identifies the associated dual network architectures and counts the number of network architectures assuming there exist N network nodes. Connectivity between network nodes is characterized as a random event. Defining the link availability P as the probability that two arbitrary network nodes in an ad hoc network are directly connected, the network connection probability $ \integral_n$(p) that any two network nodes will be directly or indirectly connected is derived. The network connection probability $ \integral_n$(p) is evaluated and graphically demonstrated as a function of p and N. It is shown that ad hoc wireless networks containing a large number of network nodes possesses the same network connectivity performance as does a fixed network, i.e., for p>0, $lim_{N\to\infty} Integral_n(p)$ = 1. Furthermore, by cooperating with fixed networks, the ad hoc network connection probability is used to derive the global network connection probability for hybrid networks. These probabilities serve to characterize network connectivity performance for users of wireless ad hoc and hybrid networks, e.g., IEEE 802.11, IEEE 802.15, IEEE 1394-95, ETSI BRAN HIPERLAN, Bluetooth, wireless ATM and the world wide web (WWW).

Object Detection from High Resolution Satellite Image by Using Genetic Algorithms

  • Kim Kwang-Eun
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.120-122
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    • 2005
  • With the commercial availability of very high resolution satellite imagery, the concealment of national confidential targets such as military facilities became one of the most bothering task to the image distributors. This task has been carried out by handwork masking of the target objects. Therefore, the quality of the concealment was fully depends on the ability and skill of a worker. In this study, a spectral clustering based technique for the seamless concealment of confidential targets in high resolution imagery was developed. The applicability test shows that the proposed technique can be used as a practical procedure for those who need to hide some information in image before public distribution

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