• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.57-64
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• 2002

Since most of the current route selection algorithms use the shortest path algorithm, network resources can not be efficiently used also traffics be concentrated on specific paths resulting in congestgion. In this paper we propose the statistical route selections(SRS) algorithm which adopts a statistical mechanism to utilize the network resource efficiently and to avoid congestion. The SRS algorithm handles requests on demand and chooses a path that meets the requested bandwidth. With the advent of the MPLS it becomes possible to establish an explicit LSP which can be used for traffic load balancing. The SRS algorithm finds a set of link utilizations for route selection, computes link weights using statistical mechanism and finds the shortest path from the weights. Our statistical mechanism computes the mean and the variance of link utilizations and selects a route such that it can reduce the variance and the number of congested links and increase the utilization of network resources. Throughout the simulation, we show that the SRS algorithm performs better than other route selection algorithms on several metrics like the number of connection setup failures and the number of congested links.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.399-404
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• 2004

Cosmic rays are ubiquitous in space, and are apparently present wherever the matter density is small enough that they are not removed by collisions with ambient particles. The essential similarity of their energy spectra in many different regions places significant general constraints on the mechanisms for their acceleration and confinement. Diffusive shock acceleration is at present the most successful acceleration mechanism proposed, and, together with transport in Kolmogorov turbulence, can account for the universal specta. In comparison to shock acceleration, statistical acceleration, invoked in many situations, has significant disadvantages. The basic physics of acceleration and transport are discussed, and examples shown where it apparently works very well. However, there are now well-established situations where diffusive shock acceleration cannot be the accelerator. This problem will be discussed and possible acceleration mechanism evaluated. Statistical acceleration in these places is possible. In addition, a new mechanism, called diffusive compression acceleration, will be discussed and shown to be an attractive candidate. It has similarities with both statistical acceleration and shock acceleration.

• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.17-24
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• 2016

In this paper, we propose a AH LSU(Advanced Hybrid QoS Routing Link State Update) Algorithm that improves the performance of Hybrid LSU(Hybrid QoS Link State State Update) Algorithm with statistical information of flow holding time in network. AH LSU algorithm has had both advantages of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. It has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and include MLMR(Meaningless LSU Message Removal) mechanism. MLMR mechanism can remove the meaningless LSU message generating repeatedly in short time. We have evaluated the performance of the MLMR mechanism, the proposed algorithm and the existing algorithms on MCI simulation network. We use the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.181-186
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• 2005

Many data sets obtained from surveys or medical trials often include missing observations. When these data sets are analyzed, it is general to use only complete cases. However, it is possible to have big biases or involve inefficiency. In this paper, we consider a method for estimating parameters in logistic linear models involving non-ignorable missing data mechanism. A binomial response and normal exploratory model for the missing data are used. We fit the model using the EM algorithm. The E-step is derived by Metropolis-hastings algorithm to generate a sample for missing data and Monte-carlo technique, and the M-step is by Newton-Raphson to maximize likelihood function. Asymptotic variances of the MLE's are derived and the standard error and estimates of parameters are compared.

• Ocean Systems Engineering
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• v.14 no.1
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• pp.53-72
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• 2024

The interaction of the blade of surface-piercing propellers (SPPs) with the water/air surface is a physical phenomenon that is difficult to model mathematically, so that such propellers are usually designed using empirical approaches. In this paper, a newly developed mechanism for measuring the torque of SPPs in an open water circuit is presented. The mechanism includes a single-component load cell and a deformable torque sensor to detect the forces exerted on the propeller. Deformations in the sensor elements lead to changes in the strain gauge resistance, which are converted into voltage using a Wheatstone bridge. The amplified signal is then recorded by a 16-channel data recording system. The mechanism is calibrated using a 6-DoF calibration system and a Box-Behnken design, achieving 99% accuracy through multivariate regression and ANOVA. Finally, the results of performance tests on a 4-blade propeller were presented in the form of changes in the torque coefficient as a function of feed rate. The results show that the new mechanism is 8% more accurate than conventional empirical methods.

• Communications for Statistical Applications and Methods
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• v.13 no.1
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• pp.101-111
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• 2006

One of the most widely used method of handling missingness in microarray data is the kNN(k Nearest Neighborhood) method. Recently Li and Gui (2004) suggested, so called PCR(Partial Cox Regression) method which deals with censored survival times and microarray data efficiently via kNN imputation method. In this article, we try to show that the way to treat missingness eventually affects the further statistical analysis.

• International Journal of Quality Innovation
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• v.4 no.1
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• pp.205-212
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• 2003

Statistical Process Control (SPC) is recognized as one of the most important tool of quality control (QC), and is one research focus in order to implement SPC quickly and effectively using computer technology and network environments. This paper proposes the principle and topology of embedded SPC based on the Internet/lntranet, emphatically discusses the embedded data sampling block, embedded network interface and SPC strategy. An example of application is given.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.491-498
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• 2013

Preliminary feasibility of REDD mechanism to combat forest degradation in North Korea is reviewed as a means of cooperation between South Korea and North Korea. North Korea has not established a national REDD+ strategy and a forest monitoring system which are required to implement REDD+ under the United Nations Framework Convention on Climate Change. Credible statistical data of forest resources is a necessary condition for implementing REDD mechanism in the developing countries. However, other than forest area data using satellite images, statistical data of forest resources of North Korea are mostly estimated based on simple hypothesis rather than transparent and robust results from national forest inventory. The review of statistical data of forest resources of North Korea shows that North Korea is in a pre-stage of REDD readiness. The study suggests that following research and cooperation agendas should be considered to implement REDD mechanism in North Korea: 1) detecting land use change since 2000, measuring carbon stock change, and identifying causes of deforestation and forest degradation; and 2) establishing a national REDD+ strategy' and a national forest inventory system in North Korea.

• Computers and Concrete
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• v.15 no.6
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• pp.989-999
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• 2015

An advanced continuum-based multi-physical single particle model was recently introduce for the hydration of tricalcium silicate ($C_3S$). In this model, the dissolution and the precipitation events are modeled as two different yet simultaneous chemical reactions. Product precipitation involves a nucleation and growth mechanism wherein nucleation is assumed to happen only at the surface of the unreacted core and product growth is characterized via a two-step densification mechanism having rapid growth of a low density initial product followed by slow densification. Although this modeling strategy has been shown to nicely mimic all stages of $C_3S$ hydration - dissolution, dormancy (induction), the onset of rapid hydration, the transition to slow hydration and prolonged reaction - the major criticism is that many adjustable parameters are required. If formulated correctly, however, the model parameters are shown here to be statistically independent and significant.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.288-295
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• 2001

Predischarges in nonuniform electric field stressed by lightning impulse voltagesin SF(sub)6-$N_2$mixtures are initiated by streamer coronas. Due to field ehnancement at a protrusion point of electrodes new ionization processes occur and a precursor, which leads to a first leader, is created. The leader proceeds step by step to the opposite electrode and the final jump bridges the test gap. It was found that the predischarge is propagated with a leader mechanism of stepwise expansion from the predischarge current waveforms measured by a shunt. The predischarge current is closely related to the amplitude and polarity of applied voltages, the gas pressure and the gap geometry. The time intervals between step leaders for the positive and negative polarities were inversely proportional to V.P$^2$. When the gas pressure increases in the positive polarity, statistical time lag to statistical time lag to streamer corona inception increase slightly, but the formative time lag to flashover is significantly decreased.