• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.156-161
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• 2001

Currently, agricultural facilities are evaluated using either basic inspections or detailed analysis. However, conventional analyses as well as methods based on fuzzy logic and rule of thumb have not been very successful in providing a clear relationship between rating and real state of agricultural facilities, because they can't provide exactly acceptable reliability of degraded structures with manager or supervisor. Therefore, in this stage, we must define probabilistic variables for representing degradation of structures being given damages during a survival time. This paper describes the application of neural network system in developing the relation between subjective ratings and parameters of agricultural reservoir as well as that between subjective and analytical ratings. It is shown that neural networks can be trained and used successfully in estimating a rating based on several parameters. The specific application problem for agricultural reservoir in the rural area of Korea is presented and database is constructed to maintain training data set, the information of inspection and facilities. This study showed that a successful training of a neural network could be useful, especially if the input data set for target problem contains parameters with a diverse combination of inter-correlation coefficients. And the networks had a prediction rating of about $^{\ast}^{\ast}^{\ast}%$. The neural network system is expected to show high performance fairly in estimate than statistical method to use equation that is consisted of very lowly interrelated variables.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.639-643
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• 2003

The emphasis is put on the detailed knowledge on manoeuvring characteristic for the safe navigation while avoiding terrible collision between ships and on the guideline to the design and operation of the ship-waterway system The numerical simulation of manoeuvring motion was carried out parametrically for different ship types, ship-velocity ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference (hereafter, $U_2$/$U_1$ ) between two ships were considered as 0.6, 1.2, 1.5. From the inspection of this investigation, it indicates the following result. Considering the interaction force only as parameter, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1.2, compared to the cases of 0.6 and 1.5 regardless of the ship types. Furthermore, regardless of the ship-velocity ratio, an overtaking and overtaken vessel can be manoeuvred safely without deviating from the original course under the following conditions: the lateral distance between two vessels is approximately kept at 0.5 times of ship-length and 5 through 10. degrees of range in maximum rudder angle. The manoeuvring characteristic based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in restricted waterways.

• Macromolecular Research
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• v.10 no.2
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• pp.91-96
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• 2002

To explore the effects of intramolecular interactions within the copolymer on the phase separation behavior of polymer blends, copolymers having two different types of intramolecular interactions, i.e., intramolecular repulsion and intramolecular attraction were prepared . In this study, poly(styrene-co-methylmethacrylate) (P(S-MMA)) having intramolecular repulsion caused by positive interaction between styrene and MMA and poly(styrene-co-ethyl-methacrylate) (P(S-EMA)) and poly(styrene-co-cyclohexylmethacrylate) (P(S-CHMA)) having intramolecular attraction caused by negative interaction between styrene and methacrylate were blended with tetramethyl poly-carbonate (TMPC). The phase behavior of blends was examined as a function of copolymer composition and blend composition. TMPC formed miscible blends with styrenic copolymers containing less than certain amount of methacrylate. The phase separation temperature of TMPC blends with copolymer such as P(S-MMA) and P(S-EMA), first increases with methacrylate content, goes through a maximum and then decreases just prior to the limiting content of methacrylate for miscibility, while that of TMPC blends with P(S-CHMA) always decreases. The calculated interaction energy for TMPC-P(S-EMA) pair is negative and monotonically increases with EMA content of the copolymer. Such behavior contradicted the general notion that systems with more favorable energetic interactions have higher LCST, The detailed inspection of the lattice-fluid theory related to the phase behavior was performed to explain such behavior.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.37-46
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• 2004

A performance analysis for newly being considered electric rail car office has been made in this study. The major purpose is to examine a proposed design in terms of its capacity and the proposed number of travels (82-84) per day. For this study we first examined the overall system configuration with detailed operational processes of cleaning and inspection. We then developed a simulation model using ARENA and designed input data from 12 selected factors and their interaction effects. A simulation run for each treatment combination of $L_{16}(2^{15})$ orthogonal array was run and 20 batch means were obtained. Through careful analyses of the results obtained, we drew a diversity of suggestions including the best factor level combination. Our confirmation experiments at the optimal level combination further validate the possibility of 82 runs and the consistency in the results.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.47.2-47.2
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• 2012

Using deep images taken at Maidanak 1.5m telescope, at McDonald 2.1m telescope and Canada-France-Hawaii Telescope, Dupont 2.5m telescope we investigated the fraction of merging galaxies in hosts of 39 AGN which are brighter than M = -22 mag and nearer than z = 0.3. We found that 16 to 17 of 39 AGN host galaxies show the evidence of mergers like tidal tail, shell via careful visual inspection. We also studied with the merging fraction of a control sample, SDSS Stripe82 early type galaxies of which surface brightness limit and bulge magnitude are similar to that of the AGN sample. We found that merging fraction of the AGN sample is higher than that of early type galaxy samples in the whole range of bulge magnitude. This result implies that AGN activity may be correlated with merging. We also investigated the detailed morphology of merging feature. At least - 1/4 of control samples classified as a tidal and tidal+dust are shell structures. On the other hand only one (5.9%) of AGN sample classified as merger shows shell structures, and almost all merging AGNs show tidal tail features. From point of view that tidal tail may be at the early stage of merging, and shell may be at the late stage of mergers, this result suggests that AGN might be evolved into early-type galaxies after merging.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1187-1194
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• 2009

During the last decade, possibility of flaw occurrences has been rapidly increased world-widely as the increase of operating times of petro-chemical facilities. For instance, from a recent in-service inspection, three different sized surface cracks were detected in welding parts of a spherical oxygen holder in Korea. While API579 code provides corresponding engineering assessment procedures to determine crack driving forces, in the present work, numerical analyses are carried out for the cracked oxygen holder to investigate effects of complex geometry, analysis model and residual stress. With regard to the detailed finite element analysis, stress intensity factors are determined from both the full three-dimensional model and equivalent plate model. Also, as an alternative, stress intensity factors are calculated for equivalent plate model by employing the noted influence stress function technique. Finally, parametric structural integrity evaluation of the cracked oxygen holder is conducted in use of failure assessment diagram method, J/T method and DPFAD method. Effects of the geometry and so forth are examined and key findings from the simulations are fully discussed, which enables to determine practical safety margins of spherical components containing a defect.

• The Korean Journal of Food And Nutrition
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• v.22 no.1
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• pp.123-131
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• 2009

The purpose of this study was to define the job description for food safety specialist, and to describe the duties and tasks of the job based on the detailed analysis of specific food safety work performed by dietitians. The job analysis was 8 professional panels and a Developing A Curriculum(DACUM) facilitator. The research was done in order to fully define the task element, process, and sequence of a food specialist and was completed by DACUM analysis. The job definition of food safety specialist is one who manages food safety through analysis, safety evaluation, inspection, and hazard blocking in all processes related to the purchase, distribution, storage, manufacture, and marketing of foods and food materials. The job description on the DACUM research chart for food safety specialist contained 7 duties and 79 tasks. Its duties were defined as the specific and independent work of a food safety specialist, and were composed of 7 duties, i.e. hazard analysis of foods and related affairs, safety evaluation of purchased food materials, safety management of food/food materials distribution/storage, safety management of food manufacture, safety examination of food marketing, administration affairs on food safety, and self-development. For the future, this study suggests a curriculum, that shall be basis of program planning and food safety operation for subjects within many schools.

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.65-77
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• 2007

This study is for the purpose of studying the validity of the construction of items and grading of the evaluation table at clinical practice used as the method of evaluation when clinical practice of Dept. of Dental Technology. 205 dental technicians in 4 cities were questioned to analyze the relation between items of the evaluation table at clinical practice and its grading. The collected materials were inspected by SAS V8 for Windows. The results are as follows: 1. Making up all the items and grading seem to be appropriate because they had the marks more than midium(more than 3.28). 2. Making up detailed items and grading seem to be trusted because they had the marks more than 3.30. 3.The significance level of the relation between items of the evaluation at clinical practice and its grading by t-inspection is p<0.0001 and so it appears to be meaningful. 4. It proved to be meaningful in result of regression analysis of the influence on the construction of the evaluation at clinical practice and its grading. With this result, further study is needed for the better methods of the evaluation in its adjustment and graduated grading among the items.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.79-79
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• 2011

Using deep images taken at Maidanak 1.5m telescope, at McDonald 2.1m telescope and Canada-France-Hawaii Telescope, we investigated the fraction of merging galaxies in hosts of 26 AGN which are brighter than M = -22.2 mag and nearer than z = 0.2. We found that 9 to 12 of 26 AGN host galaxies show the evidence of mergers like tidal tail, shell via visual inspection. We also studied with the merging fraction of a control sample, SDSS Stripe82 galaxies. Surface brightness limit and magnitude are similar to that of the AGN sample. We found that merging fraction of the AGN sample is higher than that of normal galaxy samples. This result implies that AGN activity may be correlated with merging. We also investigated the detailed morphology of merging feature. About ~1/4 of control sample classified as a tidal and tidal+dust are shell structures. On the other hand only one of the AGN sample shows shell structures. Almost all merging AGNs show tidal tail features. From point of view that tidal tail may be at the early stage of merging, and shell may be at the late stage of mergers, this result implies that AGN may be evolved into early-type galaxies after merging.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.604-612
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• 2009

Water management has been recognized as a crucial factor for achieving better performance and stability in polymer electrolyte membrane fuel cells (PEMFCs). Proper water management should provide favorable water conditions, including the local humidity, membrane water content, and liquid water saturation in PEMFCs, thereby leading to more uniform electrochemical reaction and current generation. In this study, computational fluid dynamics (CFD) simulation was conducted to investigate the effects of the cathode relative humidity (RH) on the performance of a 3 by $3\;cm^2$ PEMFC with serpentine flow fields. The CFD results showed that the best performance of the PEMFC was obtained for the cathode RH of 80%, but the performance variation was small for the cathode RH range of $60{\sim}100%$. However, the loss of the PEMFC performance was significant when the cathode RH was reduced below 40%. The reason for such performance variation was investigated through the detailed inspection of ohmic loss, activation and concentration overpotential, and water and current distributions.