• Journal of the Korean Society for Precision Engineering
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• 제26권3호
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• pp.103-112
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• 2009

A internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.681-685
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• 2004

A media-feeding (or media-transport) system is a key component in daily consumer systems such as printers, copiers and ATM's. The role of the media-transport system is to feed a medium, which is usually in the form of a thin film, to the main process in a uniform and repeatable manner. Even small slippage between the media and the feeding rollers could significantly degrade the performance of the entire system. The slippage between the medium and the feeding rollers is determined by many parameters which include the friction coefficient between the feeding rollers and the medium material, the angular velocity of the feeding rollers, and the normal force applied by feeding rollers on the medium. This paper investigates the effect of the normal force and the angular velocity of feeding rollers on the slippage of the medium. Authors have constructed a test bed for experiments, which consists of a feeding module and various measuring devices. Using regular paper as media being fed, the authors experimentally measured the slippage of the medium under various normal forces and angular velocities of driving feeding roller. Also the authors developed a novel two-dimensional simulation model for the media-transport system. The paper medium is modeled as a set of multiple rigid bodies interconnected by revolute joints and rotational springs and dampers. Simulations were executed using a multi-body dynamic analysis tool called RecurDy $n^{ⓡ}$. The slippage obtained by the simulation is compared to experimental results.ults.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.114-122
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• 2001

Leg weakness in pigs is one of the most serious problems in the pig industry. Leg weakness is responsible for an increase in the rate of culling of breeding pigs, which results in economic loss in the pig industry. Many researchers have investigated the cause of leg weakness, and that of osteochondrosis, in pigs, as well as in other mammals. For evaluating leg weakness, subjective scoring criteria have been applied, but the scoring systems varied widely. Subjective scoring systems have also been used in evaluating osteochondrosis lesions in leg joints. The lesions were scored optically, radiographically and histologically. Leg weakness and osteochondrosis are to some extent heritable traits. The heritability of leg weakness and joint lesion scores was found to range from 0.01 to 0.42. Leg weakness and osteochondrosis are associated with production traits (lean percentage and back fat depth). Nutritional aspects of leg weakness and osteochondrosis have also been extensively studied. Although the energy level of the diet may affect leg weakness and osteochondrosis, other nutritional factors seem to have very little effect. Confinement conditions also have an effect on leg weakness and osteochondrosis. Although studied extensively, the cause and etiology of leg weakness and osteochondrosis remain uncertain. It could be that there are multiple causes of leg weakness.

• Environmental Engineering Research
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• 제16권4호
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• pp.205-212
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• 2011

Reverse osmosis (RO) technology has developed over the past 40 years to control a 44% market share in the world desalting production capacity and an 80% share in the total number of desalination plants installed worldwide. The application of conventional and low-pressure membrane pretreatment processes to seawater RO (SWRO) desalination has undergone accelerated development over the past decade. Reliable pretreatment techniques are required for the successful operation of SWRO processes, since a major issue is membrane fouling associated with particulate matter/colloids, organic/inorganic compounds, and biological growth. While conventional pretreatment processes such as coagulation and granular media filtration have been widely used for SWRO, there has been an increased tendency toward the use of ultrafiltration/microfiltration (UF/MF) instead of conventional treatment techniques. The literature shows that both the conventional and the UF/MF membrane pretreatment processes have different advantages and disadvantages. This review suggests that, depending on the feed water quality conditions, the suitable integration of multiple pretreatment processes may be considered valid since this would utilize the benefits of each separate pretreatment.

• Proceedings of the Plant Resources Society of Korea Conference
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.39-39
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• 2018

The Schizandra chinensis (Korean name : omija) is a fruit native to northeast Asia that is cultivated in South Korea and China. Using 1,938 valid patents of 6 group countries, we analyzed the patent trend based on year, countries, applicants, and technology. The technologies are categorized the 10 sub-technologies such as medicine, quasi-drugs, food, feed, cosmetics, cultivation, genome, manufacture, preprocessing, and etc. The technology level and competitiveness are analyzed using patent index such as cites per patent, patent impact index, patent family size and technology strength. In Korea, patent number rapidly increasing and individual technical level is lower than other countries. However, overall technical competitiveness is estimated high due to multiple patents. We suggest that cosmetics and cultivation fields are most likely to be developed in future omiza technology development in Korea. Our study will provides to the information of technical trend to support performing of new projects for omija plant.

• The Bulletin of The Korean Astronomical Society
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• 제41권2호
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• pp.39.1-39.1
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• 2016

We report the discovery of a kiloparsec-size supershell in the outskirts of the Milky Way with the compact high-velocity cloud, HVC 040+01-282 (hereafter, CHVC040), at its geometrical center using the "Inner-Galaxy Arecibo L-band Feed Array" HI 21 cm survey data. Supershells are large gaseous shells, which could be produced by one of most energetic activities with an explosion energy more than $3{\times}1052erg$. The most promising origin is the explosion of multiple supernovae in OB associations, or alternatively, the impact of HVCs falling into the Galactic disk. We found the association between CHVC040 and the Galactic supershell by analysis of their morphological and physical properties. Our results imply that some compact HVCs can survive their trip through the Galactic halo and inject energy and momentum into the Milky Way disk.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제16권3호
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• pp.125-130
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• 2017

In this study, the influence of various factors on surface roughness was investigated using the Taguchi experimental method through high-speed machining processing. Feed rate, pitch, tool diameter, and depth of cut are widely applied to high-speed machining conditions for mold production. Each of these factors was implemented and classified into three levels; then, after high speed machining, surface roughness was measured, the S/N ratio was analyzed, and the influence on the surface roughness of control factors was analyzed quantitatively by ANOVA. Using this information, a mathematical model for predicting surface roughness was derived from multiple regression analysis. This mathematical model enables the surface roughness value after high-speed machining to be predicted at the production stage, before machining, for a wide range of machining conditions.

• Journal of the Korean Society of Propulsion Engineers
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• 제15권2호
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• pp.1-7
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• 2011

The UAV(Unmanned Aerial Vehicle) which is remotely operating with long endurance in high altitude must have a very reliable propulsion system. The precise fault diagnostic system of the turboprop engine as a propulsion system of this type UAV can promote reliability and availability. This work proposes a diagnostic method which can identify the faulted components from engine measuring parameter changes using Fuzzy Logic and quantify its faults from the identified fault pattern using Neural Network Algorithms. It is found by evaluation examples that the proposed diagnostic method can detect well not only single type faults but also multiple type faults.

• Proceedings of the Korean Society of Crop Science Conference
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.11-11
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• 2017

The most drought resistant among the five most important cereal crops, and a key dual-use (grain and biomass) crop in regions containing some of the world's most degraded soils, sorghum has inherent climate resilience that is likely to become more important under environmental conditions that are projected by many climate change models. The importance of sorghum might be further elevated by the development of productive genotypes that increase the extent and duration of soil cover beyond those of conventional annual crops, mitigating or even reversing losses of ecological capital through multiple crops from single plantings. Rich genetic and genomic resources have been developed to link Sorghum phenotypic diversity to its molecular basis, and in particular the genus has become a model for dissecting the molecular control of perenniality. Nature has made Sorghum perennial at least twice, and crosses between wild perennials and cultivated sorghums show the feasibility of developing genotypes with varying degrees of investment in perenniality while still providing harvestable food, feed, sugar and/or cellulose. Genetic analysis of progeny from these crosses is revealing the hereditary basis of traits related to ratooning and perenniality and providing diagnostic DNA markers. One perennial Sorghum species has adapted to continents and latitudes far beyond the reach of its progenitors, surviving stresses year after year that are only periodically experienced by conventional (annual) sorghum, and may also harbor novel alleles that may mitigate production challenges in conventional annual sorghums.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.499-505
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• 2010

The UAV(Unmanned Aerial Vehicle) which is remotely operating with long endurance in high altitude must have a very reliable propulsion system. The precise fault diagnostic system of the turboprop engine as a propulsion system of this type UAV can promote reliability and availability. This work proposes a diagnostic method which can identify the faulted components from engine measuring parameter changes using Fuzzy Logic and quantify its faults from the identified fault pattern using Neural Network Algorithms. It is found by evaluation examples that the proposed diagnostic method can detect well not only single type faults but also multiple type faults.