• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.97-101
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• 2002

Recently, the need for transporting and manipulating minute amount of fluids in microscale channels (so-called micro-fluidics) has been increasing, especially in biotechnology and biochemical processing. This work demonstrates that the so-called mechano-chemical process which consists of mechanical abrasive action combined with chemical process can be used to f뮤ricate micro-fluidic channels more rapidly and cost effectively than other methods. In this work, capillary filling of fluids in micro-channels was investigated by theoretical approaches and experiments. From the experimental results, it is expected that a complex micro-fluidic system can be fabricated using the micro-fabrication technique and microsystem packaging method described in this work.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.151-159
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• 2001

Flow defect of a piston-pin for automobile parts is investigated in this study. In combined cold extrusion of piston-pin, lapping defect, which is a kind of flow defect, appears by the dead metal zone. This appearance evidently happens in products with a thin thickness to be pierced for the dimensional accuracy and the decrease of material loss. The flow defect that occurs in piston-pin has bad effects on the strength and the fatigue life of piston-pin. Therefore, it is important to predict and prevent defects in the early stage of process design. The best method that can prevent flow defect is removing or reducing dead metal zone through material flow control. The finite element simulations are applied to analyze the flow defect. This study proposes processes for preventing flow defect by removing dead metal zone. Then the results are compared with the experimental ones for verification. These FE simulation results are in good agreement with the experimental ones.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.247-254
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• 2006

Rather than traditional manufacturing processes, miniature manufacturing processes usually require sophisticated equipments and characteristics of the processes of high cost and of low productivity. Contrarily, miniature stamping process can be realized in a low cost high productivity with relatively inexpensive equipments. In the meso scale, mechanical properties, especially work hardening characteristics, are discovered to be statically scattered and size dependent by intensive experimental and numerical investigations, which make the stamping process hard to apply to the miniature manufacturing. In this study, dual purpose experimental device that can be used for both miniature scale tensile test and miniature scale stamping by simple change of attachment has been developed. For the tensile test, the elongation has been measured with a combined use of a CCD camera and a linear encoder in order to account for the possibility of slippage between specimen and the grip and to ensure the accuracy of the measurement, while load has been measured with a load cell. To satisfy the required material properties for stamping, optimal annealing condition has been found by examining the microstructure of annealed specimen.

• ETRI Journal
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• v.27 no.6
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• pp.651-665
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• 2005

This paper proposes a generic security architecture designed for a multidomain and multiservice network based on programmable networks. The multiservice network allows users of an IP network to run programmable services using programmable nodes located in the architecture of the network. The programmable nodes execute codes to process active packets, which can carry user data and control information. The multiservice network model defined here considers the more pragmatic trends in programmable networks. In this scenario, new security risks that do not appear in traditional IP networks become visible. These new risks are as a result of the execution of code in the programmable nodes and the processing of the active packets. The proposed security architecture is based on symmetric cryptography in the critical process, combined with an efficient manner of distributing the symmetric keys. Another important contribution has been to scale the security architecture to a multidomain scenario in a single and efficient way.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2126-2128
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• 2001

This paper suggests that the immune network algorithm based on fuzzy set can effectively be used in tuning of a PID controller for multivariable process or nonlinear process. The artificial immune network always has a new parallel decentralized processing mechanism for various situations, since antibodies communicate to each other among different species of antibodies/B-cells through the stimulation and suppression chains among antibodies that from a large-scaled network. In addition to that, the structure of the network is not fixed, but varies continuously. On the other hand, a number of tuning technologies have been considered for the tuning of a PID controller. As a less common method, the fuzzy and neural network or its combined techniques are applied. However, in the case of the latter, yet, it is not applied in the practical field, in the former, a higher experience and technology is required during tuning procedure. Along with these, this paper used the fuzzy set in order that the stimulation and suppression relationship between antibody and antigen can be more adaptable controlled against the external condition, including noise or disturbance of plant. The immune network based on fuzzy set suggested here is applied for the PID controller tuning of multivariable process with two inputs and one output and is simulated.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.176-180
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• 2002

During the last two decades the laser beam has progressed from a sophisticated laboratory apparatus to an adaptable and viable industrial tool. Especially, in its welding mode, the laser offers high travel speed, low distortion, and narrow fusion and heat-affected zones (HAZ). The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. Although high-power laser beams have been combined with the plasma from a gas tungsten arc (GTA) torch for use in welding as early as 1980, recent work at the Ohio State University has employed a low power laser beam to initiate, direct, and concentrate a gas tungsten arcs. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process known as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma (LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well focused melted spots.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.403-407
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• 2007

The inhibitory effect of the food processing agent on growth of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes was performed with organic acid, and combination of citric acid, acetic acid, propionic acid and vanillic acid. The minimun inhibitory concentration(MIC) of propionic acid was 5,000 ppm in E. coli O157:H7, 2,500 ppm in Salmonella Enteritidis and Listeria monocytogenes. MIC of citric acid was 10,000 ppm in E. coli O157:H7 and Salmonella Enteritidis, 2,500 ppm in Listeria monocytogenes. MIC of acetic acid was 2,500ppm, while in vanillic acid was 5,000 ppm in Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. MIC of combined organc acid in E. coli O157:H7 were 2,500ppm in PC, 1,250 ppm in PA, PV, CA, CV and AV. MIC of combined organc acid in Salmonella Enteritidis were 2,500 ppm in PC, PA, PV, CA, and CV, 1,250 ppm in AV. MIC of combined organc acid in Listeria monocytogenes were 1,250 ppm in all treatment group. MIC of combined treatment of three organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes were 1,250 ppm in PCA, PCV, PAV and CAV. The inhibitory effect of organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes could be confirmed from the result of this experiment. Therefore, it was expected that the food process would increase or maintain by using organic acid.

• Journal of Powder Materials
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• v.13 no.6 s.59
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• pp.415-420
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• 2006

Nanostructured metallic materials are synthesized by bottom-up processing which starts with powders for assembling bulk materials or top-down processing starting with a bulk solid. A representative bottom-up and top-down paths for bulk nanostructured/ultrafine grained metallic materials are powder consolidation and severe plastic deformation (SPD) methods, respectively. In this study, the bottom-up powder and top-down SPD approaches were combined in order to achieve both full density and grain refinement without grain growth, which were considered as a bottle neck of the bottom-up method using conventional powder metallurgy of compaction and sintering. For the powder consolidation, equal channel angular pressing (ECAP), one of the most promising method in SPD, was used. The ECAP processing associated with stress developments was investigated. ECAP for powder consolidation were numerically analyzed using the finite element method (FEM) in conjunction with pressure and shear stress.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.43-51
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• 1999

In order to remediate hazardous waste site, a process of electrokinetically purging chemicals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes that habe igh removal efficiency and time-effectiveness in low-permeability soils such as clay. Being combined with several mechanisms-electromigration, elec troosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. The objectives of this study are; 1) the exploration of the feasibility of electrokinetic soil processing on the removal of heavy metals, 2) the investigation of applicability to the tailing-soils in aban doned mining area, 3) the examination of effects of soil pH and conductivity on the transport phenomena of elements in soils, and 4) the investigation of the applicability of the ionexchange membrance to the efficient collection of heavy metals removed from contaminated soils. With the result of this study, it is suggested that the removal efficiency is significantly influenced by applied voltage & current, type of purging solutions, soil pH, permeability and zeta potentials of soil. Although further study should be needed, it is possible to collect removed heavy metals with ion-exchange membrance in cathode compartment.

• ETRI Journal
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• v.43 no.3
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• pp.483-510
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• 2021

In computational biology, desired patterns are searched in large text databases, and an exact match is preferable. Classical benchmark algorithms obtain competent solutions for pattern matching in O (N) time, whereas quantum algorithm design is based on Grover's method, which completes the search in $O(\sqrt{N})$ time. This paper briefly explains existing quantum algorithms and defines their processing limitations. Our initial work overcomes existing algorithmic constraints by proposing the quantum-based combined exact (QBCE) algorithm for the pattern-matching problem to process exact patterns. Next, quantum random access memory (QRAM) processing is discussed, and based on it, we propose the QRAM processing-based exact (QPBE) pattern-matching algorithm. We show that to find all t occurrences of a pattern, the best case time complexities of the QBCE and QPBE algorithms are $O(\sqrt{t})$ and $O(\sqrt{N})$, and the exceptional worst case is bounded by O (t) and O (N). Thus, the proposed quantum algorithms achieve computational speedup. Our work is proved mathematically and validated with simulation, and complexity analysis demonstrates that our quantum algorithms are better than existing pattern-matching methods.