• 방사성폐기물학회지
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• 제21권3호
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• pp.303-313
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• 2023

Spent fuels (SFs) are stored in a storage pool after discharge from nuclear power plants. They can be transferred to for the further processes such as dry storage sites, processing plants, or disposal sites. One of important measures of SF is the burnup. Since the radioactivity of SF is strongly dependent on its burnup, the burnup of SF should be well estimated for the safe management, storage, and final disposal. Published papers about the methodology for the burnup estimation from the known activities of important radioactive sources are somewhat rare. In this study, we analyzed the dependency of the burnup on the important radiation source activities using ORIGEN-ARP, and suggested simple correlations that relate the burnup and the important source activities directly. A burnup estimation equation is suggested for PWR fuels relating burnup with total neutron source intensity (TNSI), initial enrichment, and cooling time. And three burnup estimation equations for major gamma sources, ¹³⁷Cs, ¹³⁴Cs, and ¹⁵⁴Eu are also suggested.

• 대한산업공학회지
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• 제14권1호
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• pp.1-15
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• 1988

DS1 transmission systems use framing bit errors, bipolar violations and code-detected errors to estimate the bit error rate when determining errored and severely errored seconds. Using the coefficient of variation under the memoryless binary symmetric channel assumption, a basic framework to evaluate these estimation schemes is proposed to provide a practical guideline in determining errored and severely errored seconds which are fundamental in monitoring the real-ime error performance of DS1 transmission systems carrying live traffic. To evaluate the performance of the cyclic redundancy check code (CRC), a computer simulation model is used. Several drawbacks of the superframe format in association with real time error performance monitoring are discussed. A few recommendations are suggested in measuring errored and severely errored seconds, and determining service limit alarms through the use of the superframe format. Furthermore, we propose a new robust scheme for determining service limit alarms which take into consideration the limitations of some estimation schemes for the time interval of one second.

• 한국산학기술학회논문지
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• 제8권3호
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• pp.639-645
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• 2007

본 연구에서는 우리나라의 인터넷전화 통화수요함수를 2001년 6월부터 2004년 12월까지의 월별 데이터를 이용하여 추정하고 있다. 추정식에서 인터넷 통화수요는 통화요금, 타서비스의 요금, 소득, 품질 등의 함수로 가정하였으며, 통화량의 부분적응모형을 이용하여 시차변수도 설명변수에 포함시켰다. 추정결과 인터넷전화는 해당 요금에 대해 탄력적인 것으로 파악되었고 소득에 대하여는 비탄력적으로 나타났다. 품질은 인터넷전화수요에 큰 영향을 미치는 것으로 파악되었으며 인터넷전화 통화수요가 설명변수의 변화에 대하여 반응하는데 있어 시차가 존재함을 보이고 있다.

• 대한산업공학회지
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• 제29권4호
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• pp.312-320
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• 2003

Recently there is a growing interest in mobile cellular network providing multimedia service. However, the link bandwidth of mobile cellular network is not sufficient enough to provide satisfactory services to users. To overcome this problem, an adaptive framework has been proposed. In this study, we propose a new method of estimating DPR(Degradation Period Ratio) in an adaptive multimedia network where the bandwidth of ongoing call can be dynamically adjusted during its lifetime. DPR is a QoS(Quality of Service) parameter which represents the ratio of allocated bandwidth below a pre-defined target to the whole service time of a call. We improve estimation method of DPR using DTMC(Discrete Time Markov Chain) model by calculate mean degradation period, degradation probability more precisely than in existing studies. Under Threshold CAC(Call Admission Control) algorithm, we present analytically how to guarantee QoS to users and illustrate the method by numerical examples. The proposed method is expected to be used as one of CAC schemes in guaranteeing predefined QoS level of DPR.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1987년도 춘계학술발표회 논문집
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• pp.67-71
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• 1987

No 1A ESS must operate in real time. Call processing capacity is the maximm number of originating plus incoming calls which the processor can process in some fixed interval of real time shile all service criteria have been satisfied. In this paper. we discuss the postcutower method of determining call processing capacity of No 1A ESS which can be applicable to an in service office and explain the usuage mithod of estimated call processing capacity of No 1A ESS in service

• 설비공학논문집
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• 제29권4호
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• pp.185-194
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• 2017

Currently, in comparison with other architectural estimations, the estimation work regarding building mechanical-service systems is time-consuming, and the process is continuously becoming more difficult because of the increased usage of the attached piping materials such as fittings and hangings in addition to their complicated construction processes. To improve this problem, the Korean authority provides a simple estimation method for the attached-material rate regarding the main piping material, which is the most time-consuming work in the architectural-mechanical estimation. However, to be an applicable method on construction sites, a proper conversion rate of the attached-piping material is still required for the proposed method regarding building usage and working types. Therefore, the purpose of this research is the calculation of the rate of the attached-piping materials such as the fittings and supports through the building of the mechanical-service work types of mechanical rooms, air conditioning, domestic water and hot-water supplies, and the drain-, vent-, and gas-piping work in office buildings that have been designed after 2010.

• 한국항행학회논문지
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• 제16권2호
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• pp.297-306
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• 2012

본 논문에서는 NLOS(non-line-of-sight) 환경에서 신뢰성 있는 LBS(location based service)를 제공하기 위해, TDOA(time difference of arrival) 위치 추정 성능 향상을 위한 시간 지연 역추적 기법을 제안하고, 다양한 사용조건에서 성능을 분석하였다. 제안하는 위치 추정 기법은 탐색영역 주변에 복수의 리더를 배치하여 송신된 신호를 리더 조합(reader combination) 수만큼 재활용 하는 방안을 적용하였다. 또한, NLOS에 의한 성능 열화를 개선하기 위해 리더가 수신한 시간에서 일정한 시간 간격을 빼주면서 위치를 재추정하는 기법을 적용하였다. 실험 결과 제안하는 시간 지연 역추적 기법을 적용하였을 때, NLOS 시간 지연 70 m에서 NLOS 리더를 3개로 가정하고 Sub-blink 수를 3회로 하였을 때 약 16 m의 RMSE 개선을 확인 할 수 있었다. 이와 같은 결과를 통해 NLOS 환경에서 LBS 서비스 제공을 위해 요구되는 위치 추정 기법으로 본 논문에서 제안하는 시간 지연 역추적 기법이 적합함을 확인하였다.

• Journal of Communications and Networks
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• 제12권6호
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• pp.624-631
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• 2010

Effective traffic matrix estimation is the basis of efficient traffic engineering, and therefore, quality of service provision support in IP networks. In this study, traffic matrix estimation is investigated in IP networks and an Elman neural network-based traffic matrix inference (ENNTMI) method is proposed. In ENNTMI, the conventional Elman neural network is modified to capture the spatio-temporal correlations and the time-varying property, and certain side information is introduced to help estimate traffic matrix in a network accurately. The regular parameter is further introduced into the optimal equation. Thus, the highly ill-posed nature of traffic matrix estimation is overcome effectively and efficiently.

• 대한간호학회지
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• 제39권1호
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• pp.95-106
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• 2009

Purpose: The purposes of this study were to explore the functional status of elderly residents and to analyze time use, and finally identify factors to predict nursing care needs in relation to functional status and health related variables. Methods: In this study a descriptive-correlational design was used. Functional status of participants was obtained through interviews, and nursing care time was examined using a 1 min time-motion study with a standardized instrument developed by Korea Long-Term Care Planning Committee (2005). Results: The mean total functional score was 65 (range 28-125) and mean total nursing care time was 144.15 min per day. There were significant positive relationships between total nursing care time, marital status, back pain, dementia, and vision impairment. Multiple regression analyses showed that a liner combination of number of illnesses, types of primary disease, ADL, IADL, cognitive function, nursing demand, and rehabilitation demand explained 42.8% of variance of total nursing time. ADL (${\beta}$=-.533) was the most significant predictor of nursing service need. Conclusion: Identifying factors that result in variations of service need has implications for adequate nursing service, estimation of optimum nurse to patient ratio, quality of care and patient safety.

• International Journal of Railway
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• 제7권1호
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• pp.24-33
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• 2014

The Korean high-speed rail (HSR) began its commercial service in 2004. This service has been created significant changes in the system of intercity passenger travels of Korea. However, the actual ridership was approximately half of the estimated one in the planning stage. In this background, this paper presents the difference between the stated preference (SP) before the HSR service and the revealed preference (RP) after it using the intercity travel mode choice models. Several meaningful differences are found in terms of the factors affecting the travel mode choice, the estimation results of model, the monetary values of time, and elasticities. While the access/egress travel time of high-speed rail is less important than in-vehicle travel time in the SP sample, they have same weight in the RP sample. Also the RP models show that the probability of choosing HSR can be decreased by the increase of the number of vehicles in household contrary to the results from the SP models. The monetary values of travel time are relatively high and the direct and cross elasticities in response to changes in level-of-service of HSR are relatively low in the RP sample. This Korean case is expected to offer referable material for preparing high-speed rail services in other countries by showing the difference between the SP and RP before/after the actual service, identifying the importance of access/egress travel time and lower direct elasticities of HSR demand.