• Journal of computational fluids engineering
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• v.7 no.3
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• pp.1-8
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• 2002

The counter jet flow which is injected against the free stream at stagnation region of blunt body for improvement of aerodynamic performance has been studied by using upwind Navier-Stokes method. The variations of drag force and upwind forward penetration depth due to changes in the stagnation thermodynamic properties of counter jet flow such as total pressure, Mach number, and total temperature have been studied. The results show that the changes in the stagnation pressure and Mach number have large effects on the wall pressure and drag force, but the total temperature does not affect the wall pressure and drag force.

• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.341-358
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• 1998

The X-ray astronomy team of the Korea Astronomy Observatory(KAO) is planning to develop a multi-cell proportional counter, adopting an anti-coincidence method to reduce its internal background. We have developed a Monte Carlo code to determine the X-ray detection efficiency of the counter. As a check of our code, we successfully reproduced the detection efficiency of Ginga/LAC. In this paper, we report the simulation results for the counter being considered in KAO.

• 한국전산유체공학회:학술대회논문집
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• 2002.05a
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• pp.29-34
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• 2002

TIn this study, the counter-jet flows which designed for improvement of aerodynamic performance of the blunt body vehicle have been analyzed. The variations of the drag force and jet penetration depth due to changes in the stagnation properties of counter jet new such as total pressure, mach number, and total temperature. The counter jet flow, which is injected toward incoming supersonic freestream at stagnation region of blunt cone-cylinder vehicle, have been studied by using upwind flux difference splitting navier-stokes method. The changes in the stagnation pressure and Mach number resulted in large effects on the wall pressure and drag force, on the other hand tile total temperature changes did not.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.462-466
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• 2007

This paper proposes an automatic bandwidth control method for the performance improvement of Binary Amplitude Shift Keying (BASK) system for Giga-Bit Modem in millimeter band. In order to improve the performance of the BASK system with a fixed bandwidth, the proposed method is to adjust a bandwidth of low pass filter in receiver using the fuzzy system. The BASK system consists of a high speed shutter of the transmitter and a counter and a repeater of receiver. The repeater consists of four stage converters, and a converter is constructed with a low pass filter and a limiter. The inputs to the fuzzy system are the reminder and integral of remainder of counter, and output is a bandwidth. We used a Viterbi algorithm to find the optimum detection from the output of the counter. Simulation results showed that the proposed system improves the performance compared to the fixed bandwidth.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.359-360
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• 2009

In this study, we propose a practical method to improve the clarity and the period of the beat in a Korean bell. Proper beating in vibration and sound is very important feature in Korean bell. An equivalent ring theory is applied and finite element analysis is performed to determine the condition of the asymmetry of the bell. The clearity and the period of the beat are improved by attaching a counter mass or decreasing local thickness. This paper shows that the improved the attaching a counter mass or decreasing local thickness. This paper of the beat are improved by attaching a counter mass or decreasing local thickness. This paper shows that the amount and position of the local variation for the required beat condition can be predicted by using the equivalent model, The predicted results are verified by the experiment.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.134-138
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• 2005

Recently many researches related with biotechnology are processed and it is the situation that research about micro fluidic devices is active. Micro fluidic devices has been one of the most widely used devices for the analysis in biotechnology because they have many advantages, flexibility, transparency, thermal and electrical stability, nontoxic, etc. In this study, micro fluidic device with PDMS is developed for particle counter which separates a small quantity of particles, The principle of micro particle counter is electrical-impedance method, and it was also applied hydrodynamic flow focusing. It is more efficient method to analyzing particles furthermore it can be applied to cell count ins for biotechnology.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.598-604
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• 1999

The thermal performance of cooling towers is affected by the temperature of inlet water, wet bulb temperature of entering air add water-air flow rate. In this study, the effects of these variables are simulated using NTU-method and experimentally investigated for the counter-flow cooling towers. The simulation program to evaluate these variables which affect the performance of cooling tower was developed. The maximum errors between the results of simulations and experiments were 3.8% under the standard design conditions and 5.4% under the other conditions. The performance was increased up to 46~50% as the water loading was increased from $6.8m^3$/$hr\cdot m^2$ to $15.9m^3$/$hr\cdot m^2$. The range was reduced up to 56~42% when the wet bulb temperature of the entering air was increased from $22^{\circ}C\; to\; 29^{\circ}C.$

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.559-569
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• 2010

We propose an RFID system based on range-free localization method. This method recognizes pre-determined reference tags first, and then checks within which reference tag the target tag is placed closest. It estimates target tag's position relative to the reference tag's position. We use Aging Counter to estimate the distance between reference and target tags using the read ratio of RFID tags. Practicality of the proposed method is verified by applying it to a library book locating system.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.421-426
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• 2013

As a greater amount of traffic have been generated on the Internet, it becomes more important to know the size of each flow. Many research studies have been conducted on the traffic measurement, and mostly they have focused on how to increase the measurement accuracy with a limited amount of memory. In this paper, we propose an explicit flow labeling technique that can be used to find out the names of the top flows and to increase the counting upper bound of the existing scheme. The labeling technique is applied to CSM (Counter Sharing Method), the most recent traffic measurement algorithm, and the performance is evaluated using the CAIDA dataset.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.34-39
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• 2003

There have been several researches to trace intruders on the Internet. But, up to now, few of them has shown a satisfactory and practicable result of the study. Recently, a little bit more active methods such as 'counter-attacking' have been considered to be an alternative to solve the problem of hacking, and some people showed a tendency to accept the method as one possible way to protect their systems. And the new intruder-retracing method suggested in this study is an improved AIAA(Autonomous Intrusion Analysis Agent) model which has been achieved by attaching the counter-attacking method to the existing tracing system. In this paper, the automatic intruder-tracking system is proposed, which was achieved through the design of the following three modules, such as the intruder-retracing module, intruder-tracing module and AIAA dispatch module.