• International journal of advanced smart convergence
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• v.11 no.3
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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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• v.14 no.3
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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.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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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).

• Communications of the Korean Mathematical Society
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• v.13 no.2
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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.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.3
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• pp.123-135
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• 2006

In this study, in order to maximize the accuracy and efficiency of the existing interpolation method fractal methods are applied. Developed FEDISA model revives the irregularity of the real topography with only a few information about base topography, which can produce almost complete geographic information. Moreover, as a tool for examining the adaptability and efficiency of the model, index of slope range $I_{SR}$, index of surface $I_{SA}$, and index of volume $I_V$ were developed. The model area is respectively set to $75m{\times}75m$, $150m{\times}150m$, $300m{\times}300m$, $600m{\times}600m$, and $1,200m{\times}1,200m$, and then the data obtained by combining the existing interpolation methods and FEDISA model were compared with real measurements. The result of the study showed the adaptability and efficiency of FEDISA model in topography restoration.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.491-500
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• 2015

In order to improve the runoff estimation accuracy of the Natural Resources Conservation Service (NRCS) curve number (CN) model, this study incorporated rainfall and maximum potential retention as contributors for initial abstraction. The modification was proposed based on 658 rank-order data of rainfall and subsequent runoff from 15 watersheds. The NRCS-CN model (M1), one of its inspired modified model (M2), and the proposed model (M3) were analyzed employing different CN approaches. Using tabulated, calculated and least squares fitted CNs ($CN_T$, $CN_C$, $CN_{LSF}$, respectively), the models' performances were evaluated based on Root Mean Square Error (RMSE), Nash-Sutcliffe Efficiency (NSE), and Percent Bias (PBIAS). Applications of model M1, M2, and M3, respectively exhibited watershed cumulative mean [RMSE (23.60, 18.12, 16.04), NSE (0.54, 0.73, 0.79), and PBIAS (36.54, 20.25, 12.00)]. Similarly, using CNC (for M1 and M2 model) and $CN_{LSF}$ (for M3 model), the performance of three models respectively were assessed based on watershed cumulative mean [RMSE (17.17, 15.88, 13.82), NSE (0.76, 0.80, 0.85), and PBIAS (3.06, 4.47, 0.11)]. The proposed model (M3) that linked all of the NRCS-CN variants showed more statistically significant agreement between the observed and estimated data.

• Journal of Ecology and Environment
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• v.39 no.1
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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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.895-907
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• 2006

In this study, in order to maximize the accuracy and efficiency of the existing interpolation method fractal methods are applied. Developed FEDISA model revives the irregularity of the real terrain with only a few information about base terrain, which can produce almost complete geographic information. The area of the model is set to $150m{\times}150m$, $300m{\times}300m$, $600m{\times}600m$, $1,200m{\times}1,200m$ to compare the real data with the data of the existing interpolation method and FEDISA model. By statistical verification of the results, the adaptability and efficiency of FEDISA model are investigated. It seems that FEDISA model will help a lot to obtain the terrain information about the changed terrain, such as the bottom of reservoirs and dams as well as large amount of destruction due to cutting and banking.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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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.