• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.699-708
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• 2015

In the testing of a software component-based robot system, generating test cases for the system is a time-consuming and difficult task that requires the combining of test data. This paper proposes an adaptive combinatorial testing method which is based on the input/output relationship among components and which automatically generates the test cases for the system. The proposed algorithm first generates an input/output relationship graph in order to analyze the input/output relationship of the system. It then generates the reduced set of test cases according to the analyzed type of input/output relationship. To validate the proposed algorithm some comparisons are given in terms of the time complexity and the number of test cases.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.9
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• pp.591-599
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• 1988

After the short-term dynamics due to the major disturbance are over, the power system may lead to viability crisis state wherein there is possibility of cascading damage. This paper presents an emergency control algorithm to alleviate the obstacles of system frequency or bus voltage during the viability crisis state. The algorithm considers the effects of controlling reactive power sources for load shedding and generation reallocation in order to alleviate the obstacles. The problem is decomposed into a subproblem I and a subproblem II. The former minimizes system frequency deviation from nominal value and the latter voltage violation of load buses. The optimization problem is solved by a reduced gradient technique which can handle a great number of inequality constraints more easily. It has been verified that the use of the proposed algorithm for IEEE 14 bus system alleviates the obstacles efficiently during the viability crisis.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.11
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• pp.2730-2741
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• 1993

A mathematical model of the seeker scan-loop which is composed of a spin-stabilized gyroscope and its driving signal processors is derived. The derived model has a transmission zero pair on the imaginary axis near to the required bandwidth. The LQG/LTR design methodology is evolved for the derived scan-loop model. To implement the designed LQG/LTR compensator to the actual plant, the compensator order is reduced using the internally balanced realization method. The performances of the LQG/LTR compensator are tested and compared with those of the P-control. Especially, stability-robustnessexperiments for model uncertainties represented in the form of time-delays are performed. It is demonstrated that the LQG/STR compensator is actually very robust to model uncertainties.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.1001-1008
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• 2012

Non-destructive testing (NDT) is a technique used in science and industry to evaluate the properties of a material without causing damage. In this paper we propose a method for segmenting radiographic images of welding in order to extract the welding defects which may occur during the welding process. We study different methods of level set and choose the model adapted to our application. The methods presented here take the property of local segmentation geodesic active contours and have the ability to change the topology automatically. The computation time is considerably reduced after taking into account a new level set function which eliminates the re-initialization procedure. Satisfactory results are obtained after applying this algorithm both on synthetic and real images.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1124-1127
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• 2003

This paper proposes a sensorless vector control of interior permanent magnet synchronous motor(IPMSM) using a Luenberger observer. Linearizeng the motor model, we can construct the linear reduced order observer for estimating rotor position and disturbance torque. The validity of the proposed scheme is confirmed by various response characteristics.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.7-11
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• 2008

In order to enhance standardization and interoperability of local level systems, AHU control network was designed with basement(8 point) and basis story(15 point) and then the network was constructed by power line communication. Each devices of AHU system were programed with neuron C of $L_{ON}W_{ORKS}$ as an open protocol. As a result of a study, each devices of the network were controlled with self dispersion process by $L_{ON}W_{ORKS}$ protocol and wiring could be reduced by power line communication.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.132-139
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• 1996

Experiments on the automatic control of NaOH concentration and on the spraying condition of NaOH solution in the alkaline degreasing process of a continuous hot-dip galvanizing line have been carried out in order to improve degreasing performance of a galvanizing sheet steel using laboratory degreasing and galvanizing simulators. The concentration of NaOH for the good degreasing has been determined to be 6.0% and more and this concentration has been able to be automatically well controlled within $\pm$0.1% by employing a solution electrical conductivity meter under a flow injection analysis condition rather than by employing a sodium ion selective electrode in the degreasing simulator. Frequent blocking of the spraying nozzles of the solution has been reduced considerably by the set-up and periodical operation of an automatic valve system in the nozzle system. By applying this automatic valve system and by automatic controlling the NaOH concentration and other ordinary variables in the degreasing process, the degreasing performance has been increased from the conventional 76% to the new 85%.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.39-49
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• 2007

Rheumatoid arthritis is an autoimmune disease involving multiple joint. In order to access the suppressive effects of JTT on rheumatoid arthritis and it's effects on immune system we investigated whether JTT could suppress the disease progression of collagen-induced arthritis. DBA/1 mice were immunized with bovine type II collagen. After a second collagen immunization, mice were treated with DW, JTT (200 or 400 mg/kg) or methotrexate (MTX, 30 mg/kg) as a positive control. Oral administration of JTT significantly suppressed the progression of CIA, which extend is comparable to that of MTX. Histological examination reveled that JTT inhibited infiltration of inflammatory cells into affected paw joint and bone erosion and cartilage destruction were greatly reduced compared with control. Total cell number of spleen, lymph node and peripheral blood were significantly reduced. The absolute number of CD19$^+$, CD3$^+$/CD69$^+$, CD4$^+$/CD25$^+$ cell in spleen from JTT treated mice were significantly decreased. The absolute number of CD19$^+$, CD3$^+$, CD3$^+$/CD69$^+$, CD4$^+$, CD4$^+$/CD25$^+$ CD8$^+$, CD49b, CD3/CD49b cells in draining lymph node were significantly increased compared with control. In peripheral blood mononuclear cells of JTT treated mice, the absolute number of CD4$^+$, CD4$^+$/CD25$^+$, CD3$^+$/CD69$^+$ cells were significantly decreased compared with control, while that of CD49b$^+$ was slightly increased. Infiltration of CD3$^+$ cells and CD11b$^+$/Gr-1$^+$ cells into paw joint was significantly reduced in JTT treated mice. The levels of pathologic cytokines including TNF-a and IL-6 in serum were significantly decreased by oral treatment with JTT The levels of IFN-g in the culture supernatant of splenocyte stimulated with CD3$^+$/CD28$^+$ or collagen were dramatically decreased, while the levels of IL-4 was increased under CD3$^+$/CD28$^+$ or collagen stimulation. Rheumatoid factors including IgG, IgM and collagen specific antibody were present much lower in the serum of JTT treated mice than control. Taken together, JTT has suppressive effects on rheumatoid arthritis by modulating immune system, and has potential to use anti-rheumatic arthritic agent in human.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.4
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• pp.358-369
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• 2000

Shielded metal arc welding machines with AC transformer have been widely used for thin-plate welding applications. Because of being bulky, heavy and of tap-changing property, so the SMAW's are changing to new power electronic circuits such as inverter circuit in order to reduce the system size and also to improve the welding performances at input output sides. The PWM inverter arc welding machine with diode rectifier has better output welding performances but it is has the plentiful harmonics and the lower input power factor. To solve these problems, input current-controlled scheme is considered for PWM inverter arc welding system, and then total input power factor is maintained to be more than 99%. Also a new combined control is proposed which can control both instantaeous welding output voltage and current under constant power condition, and as a result the variations of instantaneous current and voltage can be reduced to very narrow range in the V-I curve relationship, and hence the variance of welding current and voltage become so reduced. In addition the spatter generated during welding process is greatly reduced up to 70%. And the overall effiency can be improved up to 10%, which becomes higher when the load is lower.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.3
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• pp.349-356
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• 2013

When making a yellow layer cake, an existing chemical leavening agent, sourdough starter powder, was used instead of using baking powder in order to produce batter where the acid agent in the baking powder was reduced using baking soda. The control group had the lowest share of the batter and therefore had the highest specific volume. In a test group, the share of SP4 was low and therefore, the specific volume was high. In terms of physiochemical characteristics, the volume, symmetry and uniform index was high in SP4 in the test group. The control group had the highest moisture content followed by SP4. In terms of texture, the control group had the lowest hardness and highest springiness. In the test group, SP4 had the lowest hardness and highest springiness. The result of the sensory evaluation indicates that SP4 had the best taste and flavor. In terms of overall preference, SP4 showed significantly higher preference overall. However, it did not show any significant difference compared to the control group.