• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.517-525
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• 2008

In this paper, we cary out system level simulations to investigate the effect of cell shape(i.e., different base station displacements in the two directions defined by the street grid) on minimizing transmitter power, interference power, and blocking probability for CDMA system in urban microcellular environments. In urban microcell, path loss to the base station depends on the orientation of the street where the mobile is located. Interference from mobile stations to the base station in the reference cell is considered up to second tier. The wrap around method is used to include the second tier interference with realistic computational complexity without reducing the accuracy of interference calculations. The investigation shows that the transmitter power, interference power, and blocking probability in a cell can be reduced by proper selection of the efficient cell shape.

• Korean Management Science Review
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• v.27 no.1
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• pp.33-43
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• 2010

This paper presents a method for the estimation and analysis of the economic value of weather forecasts for CRM decision-making problems in the leisure industry. Value is calculated in terms of the customer's satisfaction returned from the user's decision under the specific payoff structure, which is itself represented by a customer's satisfaction ratio model. The decision is assessed by a modified cost-loss model to consider the customer's satisfaction instead of the loss or cost. Site-specific probability and deterministic forecasts, each of which is provided in Korea and China, are applied to generate and analyze the optimal decisions. The application results demonstrate that probability forecasts have greater value than deterministic forecasts, provided that the users can locate the optimal decision threshold. This paper also presents the optimal decision strategy for specific customers with a variety of satisfaction patterns.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.1-8
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• 1999

This paper proposes an ATM switch architecture called Output Queued Batcher-Banyan switch (OQBBS). It consists of a Sorting Module, Expanding Module, and Output Queueing Modules. The principles of channel grouping and output queueing are used to increase the maximum throughput of an ATM switch. One distinctive feature of the OQBBS is that multiple cells can be simultaneously delivered to their desired output. The switch architecture is shown to be modular and easily expandable. The performance of the OQBBS in terms of throughput, cell delays, and cell loss rate under uniform random traffic condition is evaluated by computer simulation. The throughput and the average cell delay are close to the ideal performance behavior of a fully connected output queued crossbar switch. It is also shown that the OQBBS meets the cell loss probability requirement of $10^{-6}$.

• Communications for Statistical Applications and Methods
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• v.27 no.3
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• pp.327-347
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• 2020

We consider a credit portfolio with highly skewed exposures. In the portfolio, small number of obligors have very high exposures compared to the others. For the Bernoulli mixture model with highly skewed exposures, we propose a new importance sampling scheme to estimate the tail loss probability over a threshold and the corresponding expected shortfall. We stratify the sample space of the default events into two subsets. One consists of the events that the obligors with heavy exposures default simultaneously. We expect that typical tail loss events belong to the set. In our proposed scheme, the tail loss probability and the expected shortfall corresponding to this type of events are estimated by a conditional Monte Carlo, which results in variance reduction. We analyze the properties of the proposed scheme mathematically. In numerical study, the performance of the proposed scheme is compared with an existing importance sampling method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.957-962
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• 2013

This paper proposes the new enhanced 2-D(2-Dimension) FEC scheme. It analyzes the probability of entire packet loss rate of the existing 2-D FEC by mathematical modeling, finds the problem of the existing 2-D FEC, and deduces the new enhanced 2-D FEC scheme that reduces the entire packet loss probability.

• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.23-34
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• 2013

As climate change and environmental pollution become one of the biggest global issues today, new renewable energy, especially solar photovoltaic (PV) system, is getting great attention as a sustainable energy source. However, initial investment cost of PV system is considerable, and thus, it is crucial to predict electricity generation accurately before installation of the system. This study analyzes the loss ratio of solar photovoltaic electricity generation from the actual PV system monitoring data to predict electricity generation more accurately in advance. This study is carried out with the following five steps: (i) Data collection of actual electricity generation from PV system and the related information; (ii) Calculation of simulation-based electricity generation; (iii) Comparative analysis between actual electricity generation and simulation-based electricity generation based on the seasonality; (iv) Stochastic approach by defining probability distribution of loss ratio between actual electricity generation and simulation-based electricity generation ; and (v) Case study by conducting Monte-Carlo Simulation (MCS) based on the probability distribution function of loss ratio. The results of this study could be used (i) to estimate electricity generation from PV system more accurately before installation of the system, (ii) to establish the optimal maintenance strategy for the different application fields and the different season, and (iii) to conduct feasibility study on investment at the level of life cycle.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.375-385
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• 2013

As climate change and environmental pollution become one of the biggest global issues today, new renewable energy, especially solar photovoltaic (PV) system, is getting great attention as a sustainable energy source. However, initial investment cost of PV system is considerable, and thus, it is crucial to predict electricity generation accurately before installation of the system. This study analyzes the loss ratio of solar photovoltaic electricity generation from the actual PV system monitoring data to predict electricity generation more accurately in advance. This study is carried out with the following five steps: (i) Data collection of actual electricity generation from PV system and the related information; (ii) Calculation of simulation-based electricity generation; (iii) Comparative analysis between actual electricity generation and simulation-based electricity generation based on the seasonality; (iv) Stochastic approach by defining probability distribution of loss ratio between actual electricity generation and simulation-based electricity generation ; and (v) Case study by conducting Monte-Carlo Simulation (MCS) based on the probability distribution function of loss ratio. The results of this study could be used (i) to estimate electricity generation from PV system more accurately before installation of the system, (ii) to establish the optimal maintenance strategy for the different application fields and the different season, and (iii) to conduct feasibility study on investment at the level of life cycle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1085-1089
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• 2017

Juryeonggu is a cuboctahedral die that was used during the Silla period in ancient Korea. This cuboctahedral die consists of two different penal servitudes of 14 sides; however, its equal probability distribution enables it to be used as a die. In this paper, a precise cuboctahedral die, Juryeonggu, was manufactured, and its probability was measured through experiments. Next, the probability was verified through Multibody-dynamics (MBD) modeling and analysis, and the effect of the coefficient of friction on the probability distribution was studied.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.141-144
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• 1991

In this paper, we analyze the performance of ATM switch with output buffer which has a space priority control mechanism. As we assumed that the input traffic consists of loss tolerable voice and loss sensitive data, we modeled it with MMPP(Markov Modulated Poisson Process). We confirmed that the loss probability of loss sensitive traffic decreases when we use the space priority control mechanism.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.285-292
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• 2024

When calculating sonar detection probability, underwater acoustic uncertainty is assumed to be normal distributed with a standard deviation of 8 dB to 9 dB. However, due to the variability in experimental areas and ocean environmental conditions, predicting detection performance requires accounting for underwater acoustic uncertainty based on ocean experimental data. In this study, underwater acoustic uncertainty was determined using measured mid-frequency (2.3 kHz, 3 kHz) noise level and transmission loss data collected in the shallow water of the East Sea. After calculating the predictable probability of detection reflecting underwater acoustic uncertainty based on ocean experimental data, we compared it with the conventional detection probability results, as well as the predictable probability of detection results considering the uncertainty of the Rayleigh distribution and a negatively skewed distribution. As a result, we confirmed that differences in the detection area occur depending on each underwater acoustic uncertainty.