• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.874-876
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• 2001

This paper proposes a new driving scheme for single-phase SRM. The driving scheme is very simple and inexpensive. By use of this scheme, simple power devices based on low switching losses enable to high efficiency SRM drive. Starting, one of the main problem in single-phase SRM is overcome 2 using a parking magnet. This drive system has a high efficiency and robust drive characteristics compared to that of a universal motor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1113-1115
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• 2002

Mesoporous silica, MCM-41, was synthesized by sol-gel method. The organic structure-directing agent must be removed to make the desired proes. To achieve this, alternative calcination method using microwave oven was adapted to this removal stage. Microwave calcination was shown to provide a novel, rapid and inexpensive method of praparing nanoporous material. It was studied how the porous structure, surface area and pore size distribution were changes under microwave calcination.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.91-92
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• 2006

Aluminum-doped zinc oxide (AZO) films are attractive materials as transparent conductive electrode because they are inexpensive, nontoxic and abundant element compared with indium tin oxide (ITO). AZO films have been deposited on glass (corning 1737) substrates by RF magnetron sputtering system. The electrical resistivity of AZO films was $1.81{\times}10^{-2}{\Omega}cm$ and the average transmittance in the visible range 400-800 nm was more than 76% Organic light-emitting diodes (OLEDs) with AZO/TPD/$Alq_3$/Al configuration were fabricated. The current density-voltage properties of devices were studied and compared with ITO devices fabricated under the same conditions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.208-211
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• 2001

Geosynthetic Clay Liners (GCLs) have been used for the applications of the hydraulic containment system in landfill due to inexpensive costs, simple workability and distinguished ability as a barrier material. However, bentonite of GCLs is easy to be damaged by the chemical solutions. Thus, there is a need to evaluate the potential susceptibility of GCLs causing Increase the hydraulic conductivity when GCLs are exposed to raw leachate and dissolved humic substances from landfill leachate. The hydraulic conductivity tests were performed with flexible-wall permeameter (the falling -headwater/rising -tailwater procedure) in order to verify the potential susceptibility of GCLs. The values of the hydraulic conductivity conducted with raw leachate as a permeant liquid increased considerably; however, The change of the hydraulic conductivity in the case of humic and fulvic acid were not worthy of notice. As the results of swelling tests of bentonite, however, humic substances can affect badly on the dispersion behavior of bentonite. These results indicate that humic substances dissolved in leachate could reduce the hydraulic conductivity of GCLs in landfill.

• Journal of the Speleological Society of Korea
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• no.80
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• pp.11-19
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• 2007

Most studies in the past in testing and benchmarking on Intrusion Detection System (IDS) were conducted as comparisons, rather than evaluation, on different IDSs. This paper presents the evaluation of the performance of one of the open source IDS, snort, in an inexpensive high availability system configuration. Redundancy and fault tolerance technology are used in deploying such IDS, because of the possible attacks that can make snort exhaust resources, degrade in performance and even crash. Several test data are used in such environment and yielded different results. CPU speed, Disk usage, memory utilization and other resources of the IDS host are also monitored. Test results with the proposed system configuration environment shows much better system availability and reliability, especially on security systems.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.22-25
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• 2006

Long lasting phosphor materials are in great demand for their applications in the area of light emitting diodes (LEDs), commercial displays and warning signals. After glow longevity, brightness, photo-resistance and chemical and environment stability are most important qualities that are desired for these materials. Alumina as host lattice with various rare earth elements has been found to be good at the same time inexpensive material for the synthesis of the phosphor materials. This communication explored the effect of mixed rare earth metal on the luminescence properties of these materials for the first time. Various permutations and combinations of $Sr^{2+}$ and $Ba^{2+}$ have been investigated in order to achieve robust and high luminescence characteristics in the tailored phosphor materials.

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.225-230
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• 2006

With the advent of inexpensive computing power over the past two decades, applications of Monte Carlo radiation transport techniques have proliferated dramatically. At Los Alamos, the Monte Carlo codes MCNP5 and MCNPX are used routinely on personal computer platforms for radiation shielding analysis and dosimetry calculations. These codes feature a rich palette of variance reduction (VR) techniques. The motivation of VR is to exchange user efficiency for computational efficiency. It has been said that a few hours of user time often reduces computational time by several orders of magnitude. Unfortunately, user time can stretch into the many hours as most VR techniques require significant user experience and intervention for proper optimization. It is the purpose of this paper to outline VR strategies, tested in practice, optimized for several common radiation shielding tasks, with the hope of reducing user setup time for similar problems. A strategy is defined in this context to mean a collection of MCNP radiation transport physics options and VR techniques that work synergistically to optimize a particular shielding task. Examples are offered in the areas of source definition, skyshine, streaming, and transmission.

• Journal of Chest Surgery
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• v.25 no.10
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• pp.1048-1054
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• 1992

With use of a simple, inexpensive and nonpharmacological program for blood conservation, 24 consecutive patients underwent elective or urgent coronary artery bypass grafting without need of homologous red cell transfusions and /or fresh frozen plasma transfusions in 16 patients[66.7%]. Left internal mammary artery graftings were done in 18 patients[75%], with supplemental saphenous vein grafts in all. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of ext-racorporeal circulation. The volume remaining in the oxygenator and tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the oxygenator, autotransfusion of the shed mediastinal blood was continued hourly by the next early;norning. The mean postoperative mediastinal blood loss was 364$\pm$234ml, whereas 553$\pm$383ml was autotransfused. 4 patients [16.7%] received homologous blood and an additional 4 patients[16.7%] fresh frozen plasma. Thus, in total, 16 patients[66.7%] were not exposed to any homologous blood products during the hospital stay. At discharge, the mean hemoglobin concentration was 10.3$\pm$1.6g /dl. Postoperative complications were few and there was no hospital death.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.821-824
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• 2005

This paper presents a technique to evaluate torque and speed characteristics of induction motor with the Dynamometer. The simple Dynamometer controlled via microcontroller and displayed by computer. The Microcontroller generates the PWM (Pulse Width Modulation) signal and control the duty cycle of signal for control braking level. The Buck converter is a braking unit which uses IGBT as switch in circuit. The output current of the Buck converter and output voltage of tacho generator are converted to digital signals and analyzed by microcontroller. The signals are then sent to computer for displaying torque and speed responds independent on the braking time. The test results of the Dynamometer in this research can coreectly predict the torque and speed response under reasonable tests. Moreover, this Dynamometer is easy and inexpensive to make.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.1-8
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• 2007

In this paper, we developed a file system architecture for portable multimedia devices. To enhance user convenience, the information about the stored files should be easily retrieved and organized. We defined NMD (Networked MetaData), which can organize the files in networked fashion by attaching user-defined attributes and relation between files. The NMD is stored in flash memory to utilize its nonvolatile property and low-power consumption, while multimedia files are stored in hard disk, an inexpensive mass storage. The experimental implementation showed that this architecture was able to save about 10% power compared to the hard disk NMD-store.