• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.237-242
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• 2002

The sales activity of most of small manufacturing companies is based on orders of buyers. The process of promotion, receipt and selection of orders of the manufacturers is closely coupled with the load status of the production lines. The decision on whether to accept an order or not, or the selection of optimal order set among excessive orders is entirely dependent on the schedule of production lines. However, in the real world, since the production scheduling activity is mainly performed by human experts, most of small manufacturers are suffer from being unable to meet due dates, lack of rapid decision on the acceptance of new order. To cope with this problem, this paper deals with the development of an agent for selecting an optimal order set automatically. The main engine of selection agent is based on the typical job-shop scheduling model since our target domain is the injection molding company. To solve the problem, we have formulated it as IP (Integer Program) model, and it has been successfully implemented by ILOG and selection agent. And we have suggested an architecture of an agent for tackling web based order selection problems.

• Journal of Power System Engineering
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• v.7 no.4
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• pp.12-18
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• 2003

Various measures have been tried to reduce the NOx emission from diesel engine, but with partial success because the mechanisms of NOx and PM formations appear to have trade-off relation between each other. Therefore it has been known to be difficult to reduce NOx emission and PM emission simultaneously. Two stage combustion method i,e. a combustion process which has rich combustion stage and lean combustion stage one by one, has been developed successfully to reduce NOx formation in the continuous combustion chambers such as in the boilers. But until yet it is not successful to apply the same method in intermittent combustion chamber like in the diesel engine cylinder, as it was, only several research works were carried out. In this study, devised was a uniquely shaped combustion chamber with reformed piston crown intended to keep fuel-rich condition during early stage of combustion and fuel-lean condition during next stage. It was found that the NOx emission decreased significantly at various conditions of operation with the two stage combustion type engines of PR20 type, but other values such as smoke, CO and specific fuel consumption deteriorated as usual.

• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.63-73
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• 2003

Solar flares present a number of radiative characteristics indicative of kinetic processes of high energy particles. Proper understanding of the kinetic processes, however, relies on how well we can separate the acceleration from transport characteristics. In this paper, we discuss microwave and hard X-ray bursts as a powerful tool in investigating the acceleration and transport of high energy electrons. After a brief review of the studies devoted to the kinetic process of solar flare particles, we cast them into a simple formulation which allows us to handle the injection, trap, and precipitation of flare electrons self-consistently. The formulation is then taken as a basis for interpreting and analyzing a set of impulsive and gradual bursts occurred on 2001 April 6 observed with the Owens Valley Solar Array, and HXT/WBS onboard Yohkoh satellite. We quantify the acceleration, trap, and precipitation processes during each burst in terms of relevant time scales, and also determine ambient density and magnetic field. Our result suggests that it should be the acceleration property, in particular, electron pitch angle distribution, rather than the trap condition, that is mainly responsible for the distinctive properties of the impulsive and gradual flares.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.5
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• pp.1-8
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• 2002

The sales activity of most of small manufacturing companies is based on orders of buyers. The process of promotion, receipt and selection of orders of the manufacturers is closely coupled with the load status of the production lines. The decision on whether to accept an order or not, or the selection of optimal order set among excessive orders is entirely dependent on the schedule of production lines. However, in the real world, since the production scheduling activity is mainly performed by human experts, most of small manufacturers are suffer from being unable to meet due dates, lack of rapid decision on the acceptance of new order. To cope with this problem, this paper deals with the development of an agent for selecting an optimal order set automatically. The main engine of selection agent is based on the typical job-shop scheduling model since our target domain is the injection molding company. To solve the problem, we have formulated it as IP (Integer Program) model, and it has been successfully implemented by ILOG and selection agent. And we have suggested an architecture of an agent for tackling web based order selection problems.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.5-11
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• 2004

When settled sediments in natural condition for long time were dredged by dredging process, it is natural that bulking change between sediments and dredged soils is affected by chemical injection; coagulant. Dredged sediments used in this study were sampled in the lagoon "Young rang lake" located at the east coast Sokcho city and the bulking change of dredged soils is quantitatively analysed by changing of the clay content and the amount of the flocculant and coagulant. From the experimental results, the bulking of dredged soils increased 1.69 times on the average bulking of settled sediments in natural condition in the case of the optimum chemicals addition.

• BMB Reports
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• v.48 no.12
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• pp.645-646
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• 2015

The sympathetic nervous system (SNS) or neurotransmitters in the bone marrow microenvironment has been known to regulate hematopoietic stem cell (HSC) functions such as self-renewal, proliferation and differentiation. However, the specific role of neuropeptide Y (NPY) in this process remains relatively unexplored. In this study, we demonstrated that NPY deficient mice have significantly reduced HSC numbers and impaired bone marrow regeneration due to apoptotic destruction of SNS fibers and/or endothelial cells. Moreover, NPY treatment prevented bone marrow impairments in a mouse model of chemotherapy-induced SNS injury, while conditional knockout mice lacking the Y1 receptor in macrophages did not restore bone marrow dysfunction in spite of NPY injection. Transforming growth factor-beta (TGF-β) secreted by NPY-mediated Y1 receptor stimulation in macrophages plays a key role in neuroprotection and HSC survival in the bone marrow. Therefore, this study reveals a new role of NPY in bone marrow HSC microenvironment, and provides an insight into the therapeutic application of this neuropeptide.

• Textile Coloration and Finishing
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• v.27 no.1
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• pp.11-17
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• 2015

Recently, super fiber reinforced composite materials are widely used in many industries due to high mechanical properties. In this study, 2 different types of composite materials were manufactured in order to compare their mechanical properties. Carbon and Aramid fibers were used for reinforcement materials and Bisphenol-A type epoxy resin was for matrix. Two kinds of fiber-reinforced materials were manufactured by RIM(Resin Injection Molding) method. Before manufacturing composite materials, the optimal manufacturing and curing process condition were established and the ratio of reinforcement to epoxy resin was discussed. FT-IR analysis was conducted to clarify the structure of epoxy resin. Thermal and mechanical property test were also carried out. The cross-section of composite materials was observed using a scanning electron microscope(SEM).

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.4
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• pp.41-49
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• 2008

Sensor networks are often deployed in unattended environments, thus leaving these networks vulnerable to false data injection attacks in which an adversary injects forged reports into the network through compromised nodes. Such attacks by compromised sensors can cause not only false alarms but also the depletion of the finite amount of energy in a battery powered network. In order to reduce damage from these attacks, several security solutions have been proposed. Researchers have also proposed some techniques to increase the energy-efficiency of such security solutions. In this paper, we propose a CH(Cluster Header) selection algorithm to choose low power delivery method in sensor networks. The CNP(Contract Net Protocol), which is an approach to solve distribution problems, is applied to choose CHs for event sensing. As a result of employing CNP, the proposed method can prevent dropping of sensing reports with an insufficient number of message authentication codes during the forwarding process, and is efficient in terms of energy saving.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.579-584
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• 2005

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1145-1152
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• 2002

A non-intrusive Planar Laser-Induced Fluorescence(PLIF) technique was applied to study the turbulent mixing process in a Rushton turbine reactor. Instantaneous and ensemble averaged concentration fields was obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by a thin Nd:Yag laser sheet illuminating the whole center plane of the stirred tank. The gray level images captured by a 14-bit cooled CCD camera could be transformed to the local concentration values using a calibration matrix. The dye injection point was selected at the tank wall with three quarter. height (3/4H) from the tank bottom to observe the mixing characteristics in upper bulk flow region. There exist distinct two time scales: the rapid decay of mean concentration after the dye infusion reflects the large scale turbulent mixing while the fellowed slow decay reveals the small scale molecular mixing. The temporal change of concentration variance field conjectures the two sequential processes for the batch type mixing. An inactive column of water is existed above the impeller disk, in which the fluid rotates with the shaft but is isolated from the mean bulk flow.