• International journal of advanced smart convergence
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• 제11권3호
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• pp.1-6
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• 2022

In this paper, we estimate the mean number of objects in the M/H₂/1 model for web service when the mean object size in the M/H₂/1 model is equal to that of the M/G/1/PS and M/BP/1 models. To this end, we use the mean object size obtained by assuming that the mean latency of deterministic model is equal to that of M/H₂/1, M/G/1/PS, and M/BP/1 models, respectively. Computational experiments show that if the shape parameter of the M/BP/1 model is 1.1 and the system load is greater than 0.35, the mean number of objects in the M/H₂/1 model when mean object size of M/H₂/1 model is the same as that of M/G/1/PS model is almost equal to the mean number of objects in the M/H₂/1 model when the mean object size of M/H₂/1 model is the same as that of M/BP/1 model. In addition, as the upper limit of the M/BP/1 model increases, the number of objects in the M/H₂/1 model converges to one, which increases latency. These results mean that it is efficient to use small-sized objects in the web service environment.

• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.1-7
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• 2022

This paper aims to compare the mean object size of M/G/1/PS model with that of M/BP/1 model used in the web service. The mean object size is one of important measure to control and manage web service economically. M/G/1/PS model utilizes the processor sharing in which CPU rotates in round-robin order giving time quantum to multiple tasks. M/BP/1 model uses the Bounded Pareto distribution to describe the web service according to file size. We may infer that the mean waiting latencies of M/G/1/PS and M/BP/1 model are equal to the mean waiting latency of the deterministic model using the round robin scheduling with the time quantum. Based on the inference, we can find the mean object size of M/G/1/PS model and M/BP/1 model, respectively. Numerical experiments show that when the system load is smaller than the medium, the mean object sizes of the M/G/1/PS model and the M/BP/1 model become the same. In particular, when the shaping parameter is 1.5 and the lower and upper bound of the file size is small in the M/BP/1 model, the mean object sizes of M/G/1/PS model and M/BP/1 model are the same. These results confirm that it is beneficial to use a small file size in a web service.

• 시스템엔지니어링학술지
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• 제14권1호
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• pp.83-88
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• 2018

Engineering is a sector with more than three times the industrial effectiveness of manufacturing. In the domestic engineering life cycle, the Operations & Maintenance (O&M) phase is a relatively high level of technology. Based on accumulated knowledge of O&M phase, it is necessary to advance operating technology and expand overseas O&M market expenditure. This study is the early stage of knowledge-based power plant O&M service framework reference model. In this study, we propose a conceptual model of architecture framework for power plant O&M. We survey the architecture framework and reference model and propose conceptual model of architecture framework for power plant O&M. The conceptual model of architecture framework for power plant O&M consists of stakeholder, O&M scenario, O&M technology. In particular, the O&M technology is defined as the fourth industrial revolution intelligence information technology. We defined a meta model from the conceptual model to define the power plant O&M architecture framework. In the future, we intend to development an architecture framework from the conceptual model and meta model.

• 수산해양기술연구
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• 제31권1호
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• pp.29-44
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• 1995

A model experiment on the pair midwater trawl net applicable to 800 PS class Korean pair bottom trawlers was carried out in the special-prepared experimental thank. the tank was prepared as a reverse trapezoid shape in its vertical section by digging out flat soil. The dimension of the tank showed the 9.6 W$\times$43.0 L(m) of the upper fringe and the 4.8 W$\times$38.0 L(m) of the bottom with 3.0m in depth. The depth of water was maintained 2.7m during experiment. The model net was prepared based on the Tauti's similarity law of fishing gear in 1/30 scale considering the dimension of the experimental tank. Mouth performance of the model net during towing were determined by the photographs taken in front of the net mouth with the combinations of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Vertical opening of the model nets A and B was varied in the range of 0.18~0.88 m and 0.21~0.78 m (which can be converted into 5.4~26.4m and 6.3~23.4 m in the full-scale net) respectively, and was varied predominantly by towing speed. Vertical opening (H which is appendixed m for the model net. f for the full-scale net. A and B for the types of the model net) can be expressed as the function of towing velocity$V_t$as in the model net $V_t$ : m/ sec)$H_{mA}$=1.67$e^{-1.65V_t}$ $H_{mB}$=1.15$e^{-1.13V_t}$, in the full-scale net ($V_t$ : k't) $H_{fA}$=50.27$e^-0.37V_t$ $H_{fB}$=34.46$e^{-0.26Vt}$. 2. Horizontal opening of the model nets An and b was varied in the range of 1.03~1.54m and 1.04~1.55 m (which can be converted into 30.9~46.2 m and 31.2~46.5m in the full-scale net) respectively, and was varied predominantly by distance between paired boats. Horizontal opening (W, appendixes are as same as the former) an be expressed as the function of distance between paired boats $D_b$as in the model net $W_{mA}$=0.69+0.09$D_b$ $W{mB}$=0.73+0.09$D_b$, in the full-scale net $W_{fA}$=20.81+0.09$D_b$ $W_{fB}$=22.11+0.09$D_b$ 3. Net opening area of the model net A and B was varied in the range of 0.28~1.04 $m^2$ and 0.33~0.94$m^2$(which can be converted into 252~936$m^2$ and 297~846$m^2$ in the full-scale net) respectively, and was varied predominantly by towing velocity. Net opening area ($S$, appendixes are as same as the former) van be expressed as the function of towing velocity$V_t$ as in the model net $v_t$ : m/sec) $S_{Ma}$=2.01$e^{-1.54V_T}$ $S_{mA}$=1.40$e^{-1.65V_t}$, in the full-scale net ($V_t$ : k't) $S_{fA}$=1.807$e^-0.35V_t$ $S_{fA}$=1.265$e^{-0.24V_t}$. 4. Filtering volume of the model nets A and B was varied in the range of 0.32~0.55 $m^3$ and 0.37~0.55$m^3$(which can be converted into 8.640~14.850 $m^3$ and 9.990~14.850$m3$in the full~scale net) respectively, and was predominantly varied by towing speed. filtering volume of the model net-A showed the maximum at the towing speed 0.69 m/sec(3 k't in the full-scale net), compared with that of the model net B showed at 0.92 m/sec(4 k't in the full-scale net).

• 대한수학회논문집
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• 제13권2호
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• pp.393-403
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• 1998

We consider $M_1,M_2/M/1$ retrial queues with two classes of customers in which the service rates depend on the total number or the customers served since the beginning of the current busy period. In the case that arriving customers are bloced due to the channel being busy, the class 1 customers are queued in the priority group and are served as soon as the channel is free, whereas the class 2 customers enter the retrical group in order to try service again after a random amount of time. For the first $N(N \geq 1)$ exceptional services model which is a special case of our model, we derive the joint generating function of the numbers of customers in the two groups. When N = 1 i.e., the first exceptional service model, we obtain the joint generating function explicitly and if the arrival rate of class 2 customers is 0, we show that the results for our model coincide with known results for the M/M/1 queues with smart machine.

• 한국지리정보학회지
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• 제9권3호
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• pp.123-135
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• 2006

본 연구에서는 기존에 개발된 지형 보간기법의 정확도와 효율성을 극대화하기 위해 프랙탈 기법을 적용하여 소량의 기지 지형정보로도 대상지역의 자연지형이 가지는 불규칙성을 재현하여 보다 실제지형에 가까운 지형정보를 생성할 수 있는 FEDISA 모형을 개발하였다. 또한 모형의 적합성 및 효용성을 검토하기 위한 도구로 경사도 범위지수 $I_{SR}$, 표면적 지수 $I_{SA}$, 체적 지수 $I_V$를 개발하였으며, 모형의 적용 대상면적을 $75m{\times}75m$, $150m{\times}150m$, $300m{\times}300m$, $600m{\times}600m$, $1,200m{\times}1,200m$ 등으로 다양하게 설정하여 기존의 보간 기법 및 FEDISA 모형에 의한 계산 결과와 실측자료에 대해 비교 검토를 통하여 FEDISA 모형의 효용성과 적합성을 제시하였다.

• 한국수자원학회논문집
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• 제48권6호
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• pp.491-500
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• 2015

본 연구는 NRCS-CN 방법이 산정하는 유출량의 정확성을 향상시키기 위하여 강우량과 최대잠재보유수량을 초기손실량 계산과정의 주요 기여인자로 고려하였으며, 우리나라 15개 유역에서 관측된 658개의 강우량과 유출량 자료를 이용하여 초기손실량의 수정모형을 제안하였다. 유효우량을 산정하는 방법으로는 NRCS-CN 방법(M1), NRCS-CN 방법에서 초기손실량계수를 감소시킨 방법(M2), 관측 강우-유출 관계를 바탕으로 본 연구에서 제안하는 방법(M3)을 적용하였다. 또한 USDA에서 제시하는 CN값($CN_T$), 관측자료로 부터 계산된 CN값($CN_C$) 그리고 최소자승법으로 추정한 CN값($CN_{LSF}$)을 각각의 방법에 적용하였다. 적용 결과는 RRMSE, NSE 그리고 PBIAS 등을 이용하여 평가되었다. 그 결과 $CN_T$를 M1, M2, M3에 적용한 경우 각 유역에서 평균적으로 [RMSE (23.60, 18.12, 16.04), NSE (0.54, 0.73, 0.79), PBIAS (36.54, 20.25, 12.00)]로 나타났다. 이와 비슷하게 $CN_C$를 M1과 M2에 적용하고, $CN_{LSF}$를 M3에 적용하였을 경우 각 유역에서 평균적으로 [RMSE (17.17, 15.88, 13.82), NSE (0.76, 0.80, 0.85), PBIAS (3.06, 4.47, 0.11)]로 나타났다. 따라서 본 연구에서 제안된 M3 방법을 사용하여 추정한 유효우량이 관측된 직접유출량과 통계학적으로 가장 가까운 값을 제공하는 것으로 나타났다.

• Journal of Ecology and Environment
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• 제39권1호
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• pp.71-80
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• 2016

The main goal of this study is to develop a multi-metric fishway assessment model (M_m-FA) and evaluate the efficiency of fishway. The M_m-FA model has three major fishway components with nine metrics: structural characteristics, hydraulic/hydrologic features, and biological attributes. The model was developed for diagnosing and assessing fishway efficiency and tested to Juksan Weir at the Yeongsan River Watershed. Structural characteristics of fishway included slope of the fishway (M₁), ratios of fishway width to stream width (M₂), and the proportion of orifice clogging and orifice size (M₃). Hydraulic/hydrologic characteristics included depth of fishway entrance head (M₄), depth of exit tail (M₅), and current velocity of inner fishway (M₆). Biological characteristics included fish species ratio of inner fishway to upper-lower weir (M₇), fish length distribution (M₈), and the proportion of migratory fish species to the total number of species (M₉). Overall, the assessment of fishway efficiency showed the total score of the M_m-FA model was 25 in the Juksan Weir, indicating "good condition" by the criteria of the five-level classification system. The M_m-FA model may be used as a key tool for the assessment of fishway efficiency, especially on the 16 weirs constructed for the "Four Rivers Restoration Project" after a partial calibration of M_m-FA model.

• 대한토목학회논문집
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• 제26권5D호
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• pp.895-907
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• 2006

본 연구에서는 기존에 개발된 보간 기법의 정확도와 효율성을 극대화하기 위하여 프랙탈 기법을 적용하고 소량의 기지 지형정보로도 대상지역의 자연지형이 가지는 불규칙성을 재현하여 보다 실제지형에 가까운 지형정보를 생성할 수 있는 FEDISA 모형을 개발하였다. 또한 모형의 적용 대상면적을 $150m{\times}150m$, $300m{\times}300m$, $600m{\times}600m$, $1,200m{\times}1,200m$ 등으로 다양하게 설정하여 기존의 보간 기법 및 FEDISA 모형에 의한 계산 결과와 실측자료에 대해 비교 검토 및 통계적 검증 과정을 통하여 FEDISA 모형의 효용성과 적합성에 대해 고찰해 보았다. 본 연구에서 제시된 FEDISA 모형은 저수지나 댐 저부, 대규모 절 성토로 인한 지형 파괴지역 등과 같이 기존 지형에서 변형된 지형정보를 획득하는데 많은 도움이 될 것으로 판단된다.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.1-10
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• 2007

KH University has developed a large sky simulator which is its scale suits international standard. To verify the reliability of the sky simulator, the luminance of 36 points on the inner sky surface was measured and compared with the CIE standard overcast sky model. It was found that the sky simulator can reproduce the CIE standard overcast sky condition with 1.8[%] of mean difference. To identify the differences of daylighting performance, scale model measurements were taken under a real sky and in a sky simulator. Under overcast sky conditions, two kinds of scale model experiments were conducted by using the photometric sensor Li-cor. Firstly, a 1/20 scale model of a side-lit office room 4.9[m] wide, 7.2[m] long, and 2.6[m] high was created. Five measurement points were set at 1.2[m], 2.4[m], 3.6[m], 4.8[m], and 6.0[m] from the window. The mean difference of the light factor between the sky simulator and real sky was 7.1[%]. Secondly, a 1/30 scale model of a top-lit atrium 15[m] wide, 15[m] long, and 15[m] high was created. The measurement point was set at center of the room and the well indexes of the model were set in 5 types. The mean difference of the light factor between the sky simulator and real sky was 1.7[%]. This proved that the sky simulator is fully accurate and usable for daylighting research.