• Journal of the Korea Institute of Information and Communication Engineering
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• 제18권11호
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• pp.2709-2714
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• 2014

This paper has analyzed the change of threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness of asymmetric double gate MOSFET. The asymmetric double gate MOSFET has the advantage that the factor to be able to control the current in the subthreshold region increases. The analytical potential distribution is derived from Poisson's equation to analyze the threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness. The Gaussian distribution function is used as charge distribution. This analytical potential distribution is used to derive off-current and subthreshold swing. By observing the results of threshold voltage and conduction path with parameters of bottom gate voltage, channel length and thickness, projected range and standard projected deviation, the threshold voltage greatly changed for the ratio of top and bottom gate oxide thickness. The threshold voltage changed for the ratio of channel length and thickness, not the absolute values of those, and it increased when conduction path moved toward top gate. The threshold voltage and conduction path changed more greatly for projected range than standard projected deviation.

• Journal of Korean Society of Forest Science
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• 제100권1호
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• pp.70-78
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• 2011

In this study, we develop a fire stochastic simulation model by season based on the historical fire data in Korea. The model is utilized to generate sequences of fire events that are consistent with Korean fire history. We employ a three-stage approach. First, a random draw from a Bernoulli distribution is used to determine if any fire occurs for each day of a simulated fire season. Second, if a fire does occur, a random draw from a geometric multiplicity distribution determines their number. Last, ignition times for each fire are randomly drawn from a Poisson distribution. This specific distributional forms are chosen after analysis of Korean historical fire data. Maximum Likelihood Estimation (MLE) is used to estimate the primary parameters of the stochastic models. Fire sequences generated with the model appear to follow historical patterns with respect to diurnal distribution and total number of fires per year. We expect that the results of this study will assist a fire manager for planning fire suppression policies and suppression resource allocations.

• Convergence Security Journal
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• 제22권5호
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• pp.95-105
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• 2022

The Army, Navy, and Air Force are making various efforts to develop a weapon system that incorporates the 4th industrial revolution technology so that it can be used in multi-domain operations. In order to effectively demonstrate the integrated combat power through the weapon system to which the new technology is applied, it is necessary to establish a network environment in which each weapon system can transmit and receive information smoothly. For this, it is essential to analyze the Information Exchange Requirement(IER) of each weapon system, but many IER analysis studies did not sufficiently reflect the various considerations of the actual tactical network. Therefore, this study closely analyzes the research methods and results of the existing information exchange requirements analysis studies. In IER analysis, the size of the message itself, the size of the network protocol header, the transmission/reception structure of the tactical network, the information distribution process, and the message occurrence frequency. In order to be able to use it for future IER prediction, we present a technique for calculating the information exchange requirement as a probability distribution using the Poisson distribution and the probability generating function. In order to prove the validity of this technique, the results of the probability distribution calculation using the message list and network topology samples are compared with the simulation results using Network Simulator 2.

• Korean journal of applied entomology
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• 제24권1호
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• pp.29-33
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• 1985

Every plant in $990m^2$ onion field was inspected for damages by the onion maggot. Maps were constructed every ten days to show which plants were infested and which were not from April 11 to May 21, 1984. The maps were sectioned into squares one of which contains 80 onion plants and the counts of damaged onions in each square were fitted to poisson and negative binomial distribution and tested by chi-square. We argue that the satisfactory fitness of the expected negative binomial $[P(x^2)>0.05]$ provided a useful description of the spatial distribution patterns of the damaged onions. Edge effect was tested by the differences of damage ratio and variance/mean ratio (${\sigma}^2/m$) between edge and center part. The result showed that the damage ratioes and variances of all the periods, ${\sigma}^2/m$ values after May 1 were greater in edge part than in center part. Again, the maps were sectioned into four blocks and the squares (sample units) were sectioned into quadrants. By application of the variance component technique, it was suggested that $2{\sim}8$ sample units for 5% sampling error and $1{\sim}2$ sample units for 10% error should be sampled randomly to estimate the damage ratio when $2{\sim}3$ quadrants were inspected.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제13권5호
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• pp.370-376
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• 2020

In this study, we consider a group-based random access method for group connection and delivery by grouping devices when H2H devices and large-scale M2M devices coexist in a cell in NB-IoT environment. H2H devices perform individual random access, but M2M devices are grouped according to a NPRACH transmission period, and a leader of each group performs random access. The preamble is allocated using the variable preamble allocation algorithm of the Disjoint Allocation(DA) method. The proposed preamble allocation algorithm is an algorithm that preferentially allocates preambles that maximizes throughput of H2H to H2H devices and allocates the rest to M2M devices. The access distribution of H2H and M2M devices was set as Poisson distribution and Beta distribution, respectively, and throughput, collision probability and resource utilization were analyzed. As the random access transmission slot is repeated, the proposed preamble allocation algorithm decreases the collision probability from 0.93 to 0.83 and 0.79 when the number M2M device groups are 150. In addition, it was found that the amount of increase decreased to 33.7[%], 44.9[%], and 48.6[%] of resource used.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제38B권11호
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• pp.861-869
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• 2013

We consider an information system where viruses arrive according to a Poisson process with rate ${\lambda}$. The information system has two types of anti-virus operation policies including 'real-time scan' and 'batch scan.' In the real-time scan policy, a virus is assumed to be scanned immediately after its arrival. Consequently, the real-time scan policy assumes infinite number of anti-viruses. We assume that the time for scanning and curing a virus follows a general distribution. In the batch scan policy, a system manager operates an anti-virus every deterministic time interval and scan and cure all the viruses remaining in the system simultaneously. In this paper we suggest a probability model for the operation of anti-virus software. We derive a condition under which the operating policy is achieved. Some numerical examples with various cost structure are given to illustrate the results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.683-685
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• 2012

This paper have presented the analysis of the change for threshold voltage and drain induced barrier lowering among short channel effects occurred in subthreshold region for double gate(DG) MOSFET with two gates to be next-generation devices, based on scaling theory. To obtain the analytical solution of Poisson's equation, Gaussian function been used as carrier distribution to analyze closely for experimental results, and the threshold characteristics have been analyzed for device parameters such as channel thickness and doping concentration and projected range and standard projected deviation of Gaussian function. Since this potential model has been verified in the previous papers, we have used this model to analyze the threshold chatacteristics. As a result to apply scaling theory, we know the threshold voltage and drain induced barrier lowering is changed, and the deviation rate is changed for device parameters for DGMOSFET.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1638-1654
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• 2018

The heterogeneous network (HetNet) has been one of the key technologies in Long Term Evolution-Advanced (LTE-A) with growing capacity and coverage demands. However, the introduction of femtocells has brought serious co-layer interference and cross-layer interference, which has been a major factor affecting system throughput. It is generally acknowledged that the resource allocation has significant impact on suppressing interference and improving the system performance. In this paper, we propose a hybrid-clustering algorithm based on the $Mat{\acute{e}}rn$ hard-core process (MHP) to restrain two kinds of co-channel interference in the HetNet. As the impracticality of the hexagonal grid model and the homogeneous Poisson point process model whose points distribute completely randomly to establish the system model. The HetNet model based on the MHP is adopted to satisfy the negative correlation distribution of base stations in this paper. Base on the system model, the spectrum sharing problem with restricted spectrum resources is further analyzed. On the basis of location information and the interference relation of base stations, a hybrid clustering method, which takes into accounts the fairness of two types of base stations is firstly proposed. Then, auction mechanism is discussed to achieve the spectrum sharing inside each cluster, avoiding the spectrum resource waste. Through combining the clustering theory and auction mechanism, the proposed novel algorithm can be applied to restrain the cross-layer interference and co-layer interference of HetNet, which has a high density of base stations. Simulation results show that spectral efficiency and system throughput increase to a certain degree.

• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.97-103
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• 2001

The effects of the electrohydrodynamic (EHD) flow and turbulent diffusion on the collection efficiency of a model ESP composed of the plates with a cavity were studied through numerical computation. The electric field and ion space charge density were calculated by the Poisson equation of the electrical potential and the current continuity equation. The EHD flow field was solved by the continuity and momentum equations of the gas phase including the electrical body force induced by the movement of ions under the electric field. The RNG $k-{\varepsilon}$ model was used to analyze the turbulent flow. The particle concentration distribution was calculated from the convective diffusion equation of the particle phase. As the ion space charge increased, the particulate collection efficiency increased because the electrical potential increased over the entire domain in the ESP. The collection efficiency decreased and then increased, i.e. had a minimum value, as the EHD circulating flow became stronger when the electrical migration velocity of the charged particle was low. However, the collection efficiency decreased with the stronger EHD flow when the electrical migration of the particle was higher relatively. The collection efficiency of the model ESP increased as the turbulent diffusivity of the particle increased when the electrical migration velocity of the particle was low. However, the collection efficiency decreased for increasing the turbulent diffusivity when the electrical migration of the particle was higher relatively.

• Computational Structural Engineering
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• 제6권4호
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• pp.89-98
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• 1993

As the construction of nuclear power plants are increased, nuclear wastes disposal has been faced as a serious problem. If nuclear wastes are to be buried in the underground stratum, thermo-mechanical behavior of stratum must be analyzed, because high temperature distribution has a significant effect on tunnel and surrounding stratum. In this study, in order to analyze the structural behavior of the underground which is subject to concentrated heat sources, a coupling method of nonlinear finite elements and linear boundary elements is proposed. The nonlinear finite elements (NFE) are applied in the vicinity of nuclear depository where thermo-mechanical stress is concentrated. The boundary elements are also used in infinite domain where linear behavior is expected. Using the similar method as for the problem in mechanical field, the coupled nonlinear finite element-boundary element (NFEBE) is developed. It is found that NFEBE method is more efficient than NFE which considers nonlinearity in the whole domain for the nuclear wastes depository that is expected to exhibit local nonlinearity behavior. The effect of coefficients of the rock mass such as Poisson's ratio, elastic modulus, thermal diffusivity and thermal expansion coefficient is investigated through the developed method. As a result, it is revealed that the displacements around tunnel are largely dependent on the thermal expansion coefficients.