• Journal of Preventive Medicine and Public Health
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• v.31 no.4 s.63
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• pp.875-884
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• 1998

Missing observations are common in medical research and health survey research. Several statistical methods to handle the missing data problem have been proposed. The EM algorithm (Expectation-Maximization algorithm) is one of the ways of efficiently handling the missing data problem based on sufficient statistics. In this paper, we developed statistical models and methods for survey data with multivariate missing observations. Especially, we adopted the EM algorithm to handle the multivariate missing observations. We assume that the multivariate observations follow a multivariate normal distribution, where the mean vector and the covariance matrix are primarily of interest. We applied the proposed statistical method to analyze data from a health survey. The data set we used came from a physician survey on Resource-Based Relative Value Scale(RBRVS). In addition to the EM algorithm, we applied the complete case analysis, which uses only completely observed cases, and the available case analysis, which utilizes all available information. The residual and normal probability plots were evaluated to access the assumption of normality. We found that the residual sum of squares from the EM algorithm was smaller than those of the complete-case and the available-case analyses.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.156-162
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• 2012

Outlier detection and treatment process is highly required as the first step for the statistical analysis of the monitoring data having many outliers frequently occurred in the coastal environmental monitoring projects. In this study, the outlier detection method using the approximate and detail (or residual) components of the (raw) data is suggested. The approximate and detail components of the data can be separated by the diverse filtering and smoothing methods. The decomposition of the data is carried out by the harmonic analysis and local regression curve, respectively. Then, the Grubbs' test and modified z-score method widely used to detect outliers in the data are applied to the detail components of the water temperature data. The new data set is reconstructed after removed the outliers detected by these methods. It can be shown that the suggested process is successfully applied to the outlier detection of the coastal water temperature monitoring data provided by the Real-time Information System for Aquaculture Environment, National Fisheries Research and Development Institute (NFRDI).

• Geotechnical Engineering
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• v.3 no.1
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• pp.25-38
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• 1987

The prediction of driving stresses in piles is necessary for optimum selection of driving hammers, better design of precast piles, enact assessment of drivabilities and complete description of piling specifications. However, the existing pile-driving formulas based on the theory of Newtonian impact have some defects and shortcomings; the numerical method by the wave equation analysis using electronic computer usually Involves various uncertainties and limitations which can yield erroneous outcomes because it employs soil constants of which the nature is unknown as essential parameters and ignores the effect of residual stresses set up in the pile .after each hammer blow; and the electronic measuring technique needs extra time and expense. The method developed herein is presented for the purpose of giving field engineers a reliable and convenient analytical procedure for the prediction of driving stresses along the full length of pile using the most effetive parameters without resort to electronic computer. This method is based on the fundamental mechanics of stress waves in elastic rods and takes into account the effect of residual stresses induced by reversed friction in piles.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.434-442
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• 2012

Several gateway selection schemes have been proposed that select gateway nodes based on a single Quality of Service (QoS) path parameter, for instance path availability period, link capacity or end-to-end delay, etc. or on multiple non-QoS parameters, for instance the combination of gateway node speed, residual energy, and number of hops, for Mobile Ad hoc NETworks (MANETs). Each scheme just focuses on the ment of improve only a single network performance, i.e., network throughput, packet delivery ratio, end-to-end delay, or packet drop ratio. However, none of these schemes improves the overall network performance because they focus on a single QoS path parameter or on set of non-QoS parameters. To improve the overall network performance, it is necessary to select a gateway with stable path, a path with themaximum residual load capacity and the minimum latency. In this paper, we propose a gateway selection scheme that considers multiple QoS path parameters such as path availability period, available capacity and latency, to select a potential gateway node. We improve the path availability computation accuracy, we introduce a feedback system to updated path dynamics to the traffic source node and we propose an efficient method to propagate QoS parameters in our scheme. Computer simulations show that our gateway selection scheme improves throughput and packet delivery ratio with less per node energy consumption. It also improves the end-to-end delay compared to single QoS path parameter gateway selection schemes. In addition, we simulate the proposed scheme by considering weighting factors to gateway selection parameters and results show that the weighting factors improve the throughput and end-to-end delay compared to the conventional schemes.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.89-99
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• 2011

In this paper, we propose an routing algorithm for ultra low power and high reliable transmission in WBAN environment. This algorithm is to minimize energy consumption and to maximize the life and reliability for medical devices. Also, this algorithm is not only medical devices but also non-medical devices is to minimize energy consumption and to maximize the life of device. The combination of the distance from the previous node and residual energy calculates weight. The calculated weight is used to calculate the weight of full path by cumulative weights. The full path to the smallest of the weights are set to the path. Also this algorithm is able to select another path to avoid the error path by determining the link status between nodes, when occurs link error and congestion. In this paper, we show that WSN routing algorithm based on shortest hop count routing algorithm and EAR routing algorithm compared to ensure high reliability and low power characteristic of WBAN to be verified through simulations.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1055-1067
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• 2013

We attempted to apply the HACCP system adopted in the food industry to a olive flounder (Paralichthys olivaceus) aquaculture farm to ensure the hygiene safety of farmed fish. In this study, HACCP system procedures, including HACCP team organization, critical point determination, establishment of standard limits etc., were established using Codex 12 procedures. To determine whether hazards were critical elements, we evaluated the likelihood and seriousness of each hazard element. The likelihood of residual medicine exceeding the acceptable limit in shipped fish products was demonstrated to be a critical hazard element. Management of the shipment stage was determined to be a critical control point (CCP). Checking the records for stock and release and maintaining a history of medicine use before shipping the fish were suggested as monitoring methods. The standards for acceptable residual medicine were set based on relevant laws and regulations, and then the limits were adapted and established for the CCP. An HACCP plan applicable to olive flounder farms was established.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.53-62
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• 2009

A set of experiments has been conducted on the performance sensitivity of the passive residual heat removal system (PRHRS) for an advanced integral type reactor, SMART, by using a high temperature and high pressure thermal-hydraulic test facility, the VISTA facility. In this paper the effects of the opening delay of the PRHRS bypass valves and the closing delay of the secondary system isolation valves, and the initial water level and the initial pressure of the compensating tank (CT) are investigated. During the reference test a stable flow occurs in a natural circulation loop that is composed of a steam generator secondary side, a secondary system, and a PRHRS; this is ascertained by a repetition test. When the PRHRS bypass valves are operated 10 seconds later than the secondary system isolation valves, the primary system is not properly cooled. When the secondary system isolation valves are operated 10 or 30 seconds later than the PRHRS bypass valves, the primary system is effectively cooled but the inventory of the PRHRS CT is drained earlier. As the initial water level of the CT is lowered to 16% of the full water level, the water is quickly drained and then nitrogen gas is introduced into the PRHRS, resulting in the deterioration of the PRHRS performance. When the initial pressure of the PRHRS is at 0.1MPa, the natural circulation is not performed properly. When the initial pressures of the PRHRS are 2.5 or 3.5 MPa, they show better performance than did the reference test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.171-177
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• 2012

In this paper, we proposed a algorithm and an operation boundary for fault detection of a onboard GNSS receiver. After aircraft exchange corrections computed by an aircraft receiver, a faulty aircraft receiver is detected by checking consistency of correction. For this purpose, PRC residual is used as the test statistic for fault detection of the onboard GNSS receiver. And operation boundaries are set by using DGPS position error increase with respect to the distance from a reference station. If the fault detection is performed by using aircraft only in operation boundary, the more accurate fault detection can be possible.

• The International Journal of Costume Culture
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• v.2 no.2
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• pp.80-96
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• 1999

This research focused on pattern adjustments of the stable knit garment for women. Fourteen different types of the knitted fabrics by 12 gauge, computerized flat bed machines were cut in as one half of the torso front, one half of the torso back, and one side of the sleeves for each of them. Guidelines such as the center front, the center back, the armhole, the bust-line, the waistline, the hip-line the hemline were basted on the torso patterns in the knitted fabrics. Also the grain-line, the elbow-line, and the hemline were basted on the one side of the sleeves in the same as above knitted fabrics. The torso patterns in the knitted fabrics were exhibited on the dress-forms on top of the torso patterns in Muslin, which also have the same guidelines drawn on. The distances between the guidelines on Muslin and those on the knitted fabrics for each set of the sample fabrics were measured every three days for two weeks. The fabric properties of the fourteen knitted fabrics such as fiber contents, stitch density both in the wale and course directions, weight, thickness, stretch & recovery, residual shrinkage, relaxation and drapability were laboratory tested for how these were related to finished appearance of 12 gauge, computerized flat knit garments and also in order to prove the fourteen knitted fabrics fall to a category of such as the stable knit. The results from the investigation revealed that six fabric properties such as stitch density, thickness, stretch recovery, residual shrinkage and relaxation were not so much significant factors as weight and drapability. In conclusion, fabric weight, and drapability of the fabric resulting from fiber contents were the cause of final appearance distortion of garment. When adapting patterns for stabilized, 12 gauge, computerized flat knitted fabrics, the fiber contents of the fabrics should be taken into consideration to reduce the production cost and produce better-fit garments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.37-49
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• 2000

This paper is for the first essential study on the development of unified finite element formulations for solving problems related to the dynamics/thermoelastics behavior of solids. In the first part of formulations, the finite element method is based on the introduction of a new quantity defined as heat displacement, which allows the heat conduction equations to be written in a form equivalent to the equation of motion, and the equations of coupled thermoelasticity to be written in a unified form. The equations obtained are used to express a variational formulation which, together with the concept of generalized coordinates, yields a set of differential equations with the time as an independent variable. Using the Laplace transform, the resulting finite element equations are described in the transform domain. In the second, the Laplace transform is applied to both the equation of heat conduction derived in the first part and the equations of motions and their corresponding boundary conditions, which is referred to the transformed equation. Selections of interpolation functions dependent on only the space variable and an application of the weighted residual method to the coupled equation result in the necessary finite element matrices in the transformed domain. Finally, to prove the validity of two approaches, a comparison with one finite element equation and the other is made term by term.