• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.672-683
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• 1990

The line code for ISDN subscriber loops is a critical choice in designing U-interface transceiver, since it affects system performance in a crucial way. This paper provides the performance analysis of U-interface transceiver systems employing four different line codes AMI, MMS43, VMDB5, and 2B1Q. The codes are compared using computer simulation studies, and three performance parameters of the four codes such as power spectrum, eye width, and error probability are used for the comparison. The simulation model consists of the encoder, transmit filter (root-raised cosine filter), channel, receive filter, zero-forcing equalizer, sampler, and decoder. The near-end crosstalk and addive white gaussian noise are considered as teh principal impediments.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.367-372
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• 2006

If the sea is narrowband, the Rayleigh distribution introduced by Longuet-Higgins can be used for the individual wave height distribution. However the Rayleigh distribution over-predicts the probability of high waves. Longuet-Higgins introduced alternative form of the Rayleigh distribution with an empirical constant. The wave height distribution can be fitted well by one parameter Rayleigh distribution with a proper choice of the empirical constant. The empirical constant is the ratio of the significant wave height based the time domain analysis and the spectral analysis. Here we examine wave data which contain extreme waves. Once again we confirmed that extreme wave height distribution can be modelled well by a modified Rayleigh distribution.

• Korean Management Science Review
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• v.32 no.2
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• pp.125-143
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• 2015

When studying the film industry, researchers have seldom addressed the dynamic interaction between marketing information and word of mouth in the motion picture industry mainly because of the limitation of traditional research methodologies. This study explores integration and competition among important variables influencing on audience's choice on movie selection, particularly by using a new method of agent-based modeling including competitive environment. Decision process of moviegoer composed of transition probability based on multinomial logit model, considering marketing and box-office information, critique, and word of mouth from other moviegoers. After validating the fitness of market share among released movies, this study conducted a set of simulation experiments considering several variables such as market size, change of weight between variables, and movie performance under competition. Propositions are derived from the simulation results is also suggested for future research.

• Journal of Korean Society of Rural Planning
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• v.13 no.4
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• pp.53-67
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• 2007

This study analyzed the probability that experiment stations, agricultural technology and extension centers, provincial agricultural research and extension services, central government organs, or civilian and other related organs will be the first choice of the compositional subjects of local innovation networks. While gender effect was statistically insignificant, educational level, income, main acquired information, sources of necessary information, and frequency of information acquisition sessions were significant, and the preference ranking model was highly relevant. According to the analysis, highly academic and business-related information was most likely to be acquired from the civilian sector; agricultural technology such as technology, crops/plants, storage, and circulation was most likely to be acquired from experiment stations and provincial agricultural research and extension services; and information on agricultural production was most likely to be acquired from agricultural technology centers.

• Journal of the Korean Statistical Society
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• v.27 no.1
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• pp.25-55
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• 1998

Maximum likelihood estimates (MLEs) for recursive models of categorical variables are discussed under an EM framework. Since MLEs by EM often depend on the choice of the initial values for MLEs, we explore reasonable rules for selecting the initial values for EM. Simulation results strongly support the proposed rules.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.1901-1913
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• 2014

The IEEE 802.15.6 is a communication standard for Wireless Body Area Networks (WBANs). This standard includes a prioritized slotted Aloha as a choice for medium access control. This protocol is different from the traditional version as it has integral considerations for certain priorities of users. It attempts to resolve collision by halving the probability of retransmission, lower bounded by to a minimum, in the alternate slots to follow. In this paper, we present an analytical model to compute the non-saturated throughput of this protocol in the presence of finite number of nodes. The model is validated against simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.21-31
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• 1999

This paper considers how to structure the incentive system between a buy and a single supplier of raw materials when early shipments are forbidden. And this paper is used to take the supplier's behavior into account in the buyer's choice of incentives. Combinations of two types of incentives that the buyer might offer are considered : (1) a fixed value incentive and (2) an incentive that decreases in value as time elapses. Given a desired probability of on time delivery, optimal incentives are found by specifying indifference curves for on time delivery and assessing the expected total cost of incentive schemes along that curve. Difficulties of using incentive to achieve 100% on time delivery are considered and two example flow time distributions are presented.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.55-61
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• 2008

Incremental encoder is a common choice for measuring the rotational angle of an axis. It produces, however, some measurement errors, if some kinds of rotational vibration are occurred. Even by increasing the number of slits on the circular peripheral, these kinds of error can not be removed. It only decreases the probability of the error being generated by making the magnitude of encoder resolution smaller than that of the axial vibration. This paper investigates the error mechanism of incremental encoder and suggests a digital logic circuit that prevents the measurement error to happen.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4625-4641
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• 2016

The performances of two commonly used feature detectors for wireless energy-harvesting cognitive radio systems are compared with the energy detector under energy causality and collision constraints. The optimal sensing duration is obtained by analyzing the effect of the detection threshold on the average throughput and collision probability. Numerical examples show that the covariance detector has the optimal sensing duration depending on an appropriate choice of the detection threshold, but no optimal sensing duration exists for the ratio of average energy to minimum eigenvalue detector.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.4
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• pp.351-362
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• 2020

Adaptive behaviors are one of ubiquitous features in evolutionary dynamics of populations, and certain adaptive behaviors can be witnessed by individuals' movements which are generally affected by local environments. In this paper, by revisiting the previous work, we investigate the sensitivity of species coexistence in the system of cyclic competition where species movement can be affected by local environments. By measuring the extinction probability through Monte-Carlo simulations, we find the relativistic effect of weights of local fitness and exchange rate for adaptive movement on species biodiversity which promotes species coexistence as the relativistic effect is intensified. In addition, by means of basins of initial conditions, we also found that adaptive movement can also affect species biodiversity with respect to the choice of initial conditions. The strong adaptive movement can eventually lead the coexistence as a globally stable state in the spatially extended system regardless of mobility.