• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.128-134
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• 2002

In this paper, the performance on the PN code acquisition of DS/CDMA system was analyzed using the Nakagami-m probability density function considered fading environment. The equations on detection probability, $P_D$ and false alarm probability, $P_{FA}$, decision variables affecting the PN code acquisition time were derived and proved using simulation in order to analyze the performance. In conclusion, It was necessary increasing the gain of PLL for correcting phase errors and improving the acquisition performance of PN code in apply to the rake receiver.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.499-511
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• 2000

We consider a stable tandem network which consists of two M/M/1 nodes and study the probability that the total backlog exceeds a large level N. Since the excessive backlog is a rare event, it is difficult to estimate this probability efficiently by using the crude Monte Carlo simulation. Instead we perform the ;$h$-transform proposed by McDonald(1999) to obtain the twisted network, in which the node with the larger load is overloaded. Then we use it to run the fast simulation.

• Communications of the Korean Mathematical Society
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• v.18 no.4
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• pp.725-736
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• 2003

Let $A_1,{\;}A_2,...,A_n$ be a sequence of events on a given probability space. Let $m_n$ be the number of those $A'_{j}s$ which occur. Upper bounds of P($m_n{\;}\geq{\;}1) are obtained by means of probability of consecutive terms which reduce the number of terms in binomial moments $S_2,n,S_3,n$ and $S_4,n$.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.241-247
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• 2008

In this study we consider an M/D/1 queue with a finite buffer. Due to the finiteness of the buffer capacity arriving customers can not join the system and turn away without service when the buffer is full. Even though a computational method for blocking probabilities in an M/D/1/K queue is already known, it is very complex to use. The aim of this study is to propose a new way to compute blocking probability by using (max,+)-algebra. Our approach provide a totally different and easier way to compute blocking probabilities and it is, moreover, immediately applicable to more generous queueing systems.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.1
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• pp.1-7
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• 2009

Tracking and detecting targets by the M/W seeker is affected by the clutter reflecting from the earth's surface. In order to detect the look-down retreating targets, which appear in the sidelobe clutter region, in the M/W seeker of High PRF mode, it is necessary to understand statistical characteristics of the surface sidelobe clutter. Statistical analysis of sidelobe clutter is conducted for several configurations of the surface using data obtained by the CFT (Captive Flight Test) of the M/W seeker in High PRF mode. The probability density function(PDF) fitting is conducted for several configuration and conditions of the surface. PDFs and PDF parameters, which best describe statistical distribution of sidelobe clutter, are estimated.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.198-206
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• 2019

A new methodology to analyze the nuclear material accountability for pyroprocessing system is developed. The $Pu-to-^{244}Cm$ ratio quantification is one of the methods for Pu accountancy in pyroprocessing. However, an uncertainty in the $Pu-to-^{244}Cm$ ratio due to the non-uniform composition in used fuel assemblies can affect the accountancy of Pu. A random variable, LOPu, is developed to analyze the probability of detection for Pu diversion of hypothetical scenarios at a pyroprocessing facility considering the uncertainty in $Pu-to-^{244}Cm$ ratio estimation. The analysis is carried out by the hypothesis testing and the event tree method. The probability of detection for diversion of 8 kg Pu is found to be less than 95% if a large size granule consisting of small size particles gets sampled for measurements. To increase the probability of detection more than 95%, first, a new Material Balance Area (MBA) structure consisting of more number of Key Measurement Points (KMPs) is designed. This multiple KMP-measurement for the MBA shows the probability of detection for 8 kg Pu diversion is greater than 96%. Increasing the granule sample number from one to ten also shows the probability of detection is greater than 95% in the most ranges for granule and powder sizes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.156-163
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• 2013

Collision probability is the most common method to measure the risk of space debris, it is widely used that two dimensional linear collision probability using the closest approach distance. This paper represents the characteristics of object that approach KOMPSAT 2, 3, 5 that have operated or will be operated by Korea. And more precise method than two dimensional linear collision probability, we analyzed the properties of three dimensional nonlinear collision probability using STK/Nonlinear Collision Probability Tool. Through this, efficiency of three dimensional nonlinear collision probability for KOMPSAT series satellites was investigated. The result represents that three dimensional nonlinear collision probability showed the precise outcome at a relative velocity of less than 350m/s. Also, KOMPSAT series satellites appeared to few low relative velocity approaches and showed low efficiency for the three dimensional nonlinear collision probability.

• Explosives and Blasting
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• v.41 no.4
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• pp.1-8
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• 2023

On August 4, 2020, 2750 tons of ammonium nitrate stored in a storage warehouse at the Port of Beirut exploded. This explosion is said to be the largest ammonium nitrate explosion ever. By applying the TNT equivalency method, TNT equivalent amount corresponding to the explosion energy of 2750 tons of ammonium nitrate was calculated, and it is found to be 856 tons. Overpressure and impulse were calculated in a range up to 3600 m from the blast using the Kingery-Bulmash explosion parameter calculator tool. As the distance from the explosion center increases, the overpressure and impulse decrease exponentially, but the overpressure decreases more significantly, showing that overpressure is more affected by distance than the impact. As a result of applying the damage criteria to evaluate the effects of overpressure and impulse on the structure, the critical distances at which partial collapse, major damage, and minor damage to the structure occur are found to be approximately 500, 800, and 2200 m from the center of the explosion, respectively. The probit function was applied to evaluate the probability of damage to structures and human body. The points where the probability of collapse, major damage, minor damage, and breakage of window-panes to structures are greater than 50% are found to be approximately 500, 810, 2200, and 3200 m, respectively. For people within 200 m from the center of the explosion, the probability of death due to lung damage is more than 99%, and the 50% probability of eardrum rupture is approximately 300 m. The points with a 100% probability of death due to skull rupture and whole body impact due to whole body displacement are evaluated to be 300 and 100 m, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1805-1811
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• 2005

We analyzed of the receiver which received OOK and the FSK transmission signal that were a general digital transmission technique in a WDM system. We expressed various error probability with the m which was bandwidth and a bit numerical function and carried out performance evaluation of a receiver in a performance evaluation way. When error probability was $10^{-4}$ which is m=10, as for the receive sensitivity of OOK, the $1.7{\times}10^2$, FSK got $2.2{\times}10^2$ through simulation. And the receive sensitivity of OOK and FSK was able to get each $2.15{\times}10^2$ and $3.07{\times}10^2$ when it was error probability of $10^{-9}$ which is m = 25. Transmission of 23Gb/S showed that it was possible when we does the $10^{-9}$ that was basis error probability of a light communication system with a basis through this, and a coding profit was with for and transmission capacity of 75Gb/s confirmed that it was possible if a code rate was with 0.8.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.30-38
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• 2020

In order to construct a dam, the diversion facility such as cofferdam and a diversion tunnel should be installed in advance. And size of a cofferdam depends on type of a main dam. According to the Korea Dam Design Standard, if the main dam is a concrete dam, design flood of the cofferdam is 1~2 years flood frequency. This means that overflow of the cofferdam occurs one time for 1 or 2 years, therefore, stability of the cofferdam should be secured against any overflow problem. In this study, failure probability analysis for the concrete cofferdam is performed considering the overflow. First of all, limit state function of the concrete cofferdam is defined for overturning, sliding and base pressure, and upstream water levels are set as El. 501 m, El. 503 m, El. 505 m, El. 507 m. Also, after literature investigation research, probabilistic characteristics of various random variables are determined, the failure probability of the concrete cofferdam is calculated using the Monte Carlo Simulation. As a result of the analysis, when the upstream water level rises, it means overflow, the failure probability increases rapidly. In particular, the failure probability is largest in case of flood loading condition. It is considered that the high upstream water level causes increase of the upstream water pressure and the uplift pressure on the foundation. In addition, among the overturning, the sliding and the base pressure, the overturing is the major cause for the cofferdam failure considering the overflow.