• 한국정보전자통신기술학회논문지
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• 제8권6호
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• pp.439-444
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• 2015

통신, 교통, 전력 및 물 공급 시스템과 같은 사회 인프라 시스템은 이제 구성 요소 장애, 보안 공격과 자연 재해 등을 포함하여 다양한 종류의 위협에 직면하고 있다. 이러한 바람직하지 못한 사건이 발생할 때마다, 사회 기반의 기능정지시간이 사회에 치명적인 결과를초래하기 때문에 가능한 한 빨리 시스템을 복구하는 것이 중요하다. 특히 네트워크상에서의 장애가 발생했을 때, 링크 장애를 자동적으로 복구해야 그 피해를 최소화 할 수 있다. 또한 네트워크 장애시 고객이 인식하기 전에 서비스가 복구 될 수 있게 하면 그 효과는 더 클 것이다. 본 논문에서는 네트워크에서의 자동복구성과 비용사이의 관계를 분석한다.

• 한국동물위생학회지
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• 제23권1호
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• pp.1-8
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• 2000

This study was carried out to simultaneous determination of penicillin G and chloramphenicol in livestock products by HPLC. The results obstained were as follows; 1. Penicillin G and chloramphenicol were analyzed by HPLC on symmetry $C_{18}$ column with acetonitrile-0.1 M phosphate buffer containing 0.0157 M thiosulfate (25 : 75) as mobile phase at UV 325nm and 280nm, respectively. 2. Samples were applied to a SeP-Pak $C_{18}$ cartridge, from which eluted penicillin derivatized with 2 M 1,2,4-triazole containing 0.001 M mercuric chloride. 3. The average recovery rates of penicillin G and chloramphenicol were 81.8% and 80.3%, respectively, and the detection limits were 5 ppb (5$\mu\textrm{g}$/kg: 7.9IU/kg) for penicillin G and chloramphenicol in porcine and bovine muscle.

• 한국동물위생학회지
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• 제21권3호
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• pp.261-266
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• 1998

A method for the determination of noboviocin in milk was presented by high performance liquid chromatography(HPLC). The novobiocin in the spiked sample was extracted with methanol and evaporated under vacuum. After evaporating, the residue was mixed with distilled water for 2$m\ell$, filtrates with 0.45$\mu\textrm{m}$ acrodisc was injected into HPLC. The results obtained were as follows ; 1. The calibration curve of novobiocin was showed constantly linear(r 0.999) in the range of 100~500ng/$m\ell$. 2. The mean recovery rate of novobiocin from the spiked milk sample were 88~98%. 3. The coefficients of variation were 2.6~5.8% 4. The lowest detectable limit of novobiocin was 25ppb.

• Journal of information and communication convergence engineering
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• 제2권1호
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• pp.9-14
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• 2004

In this paper the modeling of the RLP layer in CDMA2000 is presented, which uses the NAK based ARQ scheme for Random Error Channels. The RLP performs a partial link recovery through limited number of RLP frame transmission in case of frame error. In case when the RLP fails due to excessive frame error, the control is passed on to the higher (TCP) layer. The TCP layer provides the complete end-to-end recovery. Thus the reliable performance at the TCP/RLP is essential to maintain the required Quality of Service in the DS-CDMA wireless links. The modeling is done for the performance analysis of the system in terms of the throughput and the mean extra delays, which are calculated analytically and are compared with the results generated by the simulations. This paper studies the effect of the random errors over different types of RLP frame formats and also the performance of the NAK based ARQ mechanism used under these conditions. The simulation provides with the over all characteristics of the throughput and the mean extra delay in terms of realistic environment parameters like Eb/No and probability of packet error (PE), based on the channel conditions.

• 한국통신학회논문지
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• 제32권1B호
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• pp.22-30
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• 2007

본 논문에서는 분산 객체 관리의 편의성을 제공하고, 고장 발생시에도 안정된 서비스를 가능케 하는 고장포용 객체그룹(Fault-Tolerant Object Group, FTOG) 프레임워크를 제안한다. FTOG 프레임워크는 서비스 우선순위와 체크포인트 방법을 이용하여 두 가지의 고장 회복 방안을 제공하며 퍼지 기반의 부하 추론 과정을 통한 부하 분산을 수행하여 서비스 실행에서의 효율성을 높인다. 또한 가상의 홈네트워크 환경을 구성하고 FTOG 프레임워크를 적용하여 시뮬레이션을 통해 분산되어 있는 객체들의 관리 및 부하 분산 등 본 모델의 안정성 및 신뢰성을 검증하였다.

• Journal of Nutrition and Health
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• 제46권6호
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• pp.573-588
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• 2013

The objective of this study is to investigate various jobs and foodservice environments, as well as work performances of school foodservice dietitians and nutrition teachers in accordance to the years of service in Daejeon and Chungnam provinces. A survey was conducted among school foodservice dietitians and nutrition teachers; a total of 415 from selected elementary, middle and high schools in the areas. In this study, we surveyed the participants and analyzed the current state of general characteristics, status of their job environments and foodservice environments by frequency, and the averages and differences in work performance with regard to 12 work parts and 57 works using one-way ANOVA and Duncan's multiple range test according to the years of service. Six parts among 12 work parts were significantly different in work performance according to the years of service. The 6 work parts were menu (nutrition) management, utensil recovery and management, sanitation management, foodservice administration & evaluation, dietary habit guide, and other works. The 11-15 years group ranked as the top on the total score and means of work performance. While the 16-years or more group, 6-10 years group, and under 5 years group followed consecutively. Correlation analysis between job or foodservice environments and work performances showed that work performances of school dietitians were mostly influenced by employment status, education level, and annual salary among the variables of job or foodservice environments. Other works, dietary habit guides and menu management were mostly influenced by variables of job and foodservice environments.

• 서비스연구
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• 제6권2호
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• pp.215-232
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• 2016

본 연구에서는 서비스 실패 상황에서 서비스 자체의 요인, 소비자의 내적 요인, 주위 상황 등의 외적 요인으로 나누어 소비자가 지각하는 서비스 실패의 정도에 영향을 미치는 요인들을 밝히고 그에 따른 소비자의 서비스 실패 상황에 대한 불평 행동과 이탈 행동에 관한 연구를 진행하였다. 가설 검증 결과, 과거 경험의 만족도, 기입이미지, 서비스 중요도는 서비스 실패에 대한 허용 영역에 부(-)의 영향을 미쳤다. 서비스 중요도는 지각된 서비스 실패의 심각성에는 정(+)의 영향을 미쳤다. 서비스 실패에 대한 허용 영역은 지각된 서비스 실패의 심각성에 부(-)의 영향을 미쳤다. 따라서 가설 1, 가설 2, 가설 3, 가설 4, 가설 5는 지지되었다. 반면, 사회비교에 대한 의식 수준은 지각된 서비스 실패의 심각성에 영향을 미치지 않는 것으로 나타났다. 부정적 감정 성향 또한 지각된 서비스 실패의 심각성에 영향을 미치지 않는 것으로 나타났다. 따라서 가설 6, 가설7은 기각되었다. 본 연구는 서비스산업의 연구자 및 제공자들에게 다음과 같은 시사점을 제공할 수 있다. 연구결과를 통해서 서비스 실패 및 회복 프레임워크를 개발에 도움을 줄 수 있으며, 특히 서비스 제공자에게 서비스 실패를 회복하기 위한 특정 가이드라인 제공을 통해서 서비스 회복 전략에 효과적인 심각성 포인트를 제시하였다.

• Journal of information and communication convergence engineering
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• 제10권3호
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• pp.231-236
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• 2012

For real-time wireless sensor network applications, it is essential to provide different levels of quality of service (QoS) such as reliability, low latency, and fault-tolerant traffic control. To meet these requirements, an (m,k)-firm based real-time routing protocol has been proposed in our prior work, including a novel local transmission status indicator called local DBP (L_DBP). In this paper, a fault recovery scheme for (m,k)-firm real-time streams is proposed to improve the performance of our prior work, by contributing a delay-aware forwarding candidates selection algorithm for providing restricted redundancy of packets on multipath with bounded delay in case of transmission failure. Each node can utilize the evaluated stream DBP (G_DBP) and L_DBP values as well as the deadline information of packets to dynamically define the forwarding candidate set. Simulation results show that for real-time service, it is possible to achieve both reliability and timeliness in the fault recovery process, which consequently avoids dynamic failure and guarantees meeting the end-to-end QoS requirement.

• 한국동물위생학회지
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• 제30권3호
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• pp.421-428
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• 2007

This study was conducted two kinds of aims: 1) to modify the analytical methods (conditions) by high performance liquid chromatography - fluorescence detector for the detection of residual ivermectin in raw milk, 2) to provide basic information for the evaluation of standard of the residual ivermectin in raw milk. It could be considerable that negative ion spectra can be better method in the LC/MS analysis for the detection of residues, Characteristic daughter ions were observed in negative ion spectra, however, linear line was not formed in positive ion one. Three Holstein cows ($500{\pm}10kg$) were applied to commercial ointment of ivermectin just one time at the first day of test, and residues in raw milk were examined for 20day after administration. The limit of detection (LOD) was 0.65ng (n=5) by HPLC/FLD, and recovery rates were $87.85%{\sim}99.47%$. The peak was observed at the 4th day, and residues lasted to the end. Thus ivermectin was prohibited when lactating.

• 한국통신학회논문지
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• 제29권9B호
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• pp.791-798
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• 2004

네트워크 상에 장애가 발생 시에는 서비스들의 QoS 요구사항을 만족시킬 수 있는 또 다론 백업 경로를 사용 하여 서비스해야 한다. 따라서 본 논문에서는 IP 네트워크 상에 발생된 단일 회선 장애를 위해 simple PFC(s-PFC) 기법과 다중 회선 장애를 위한 iterative PFC(i-PFC) 그리고 라우터와 같은 노드 장애를 복구하기 위한 fault_node Avoidance PFC(a-PFC) 기법들을 제안하고 이를 기반으로 Direct_destination Rerouting(DR) 기법 을 최소 재라우팅 비용 문제를 통해 성능 비교 분석하기로 한다.