• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.89-94
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• 2011

The EGR system is one of important components in diesel engine. The regulation on NOx emission has been tightened up. Therefore, it is a significant issue to develop and commercialize the high efficient EGR cooler system that reduces NOx emission in DI diesel engine. Key performance factor of the EGR cooler system is how to properly design both wavy cooling fins and gas tubes. This paper proposes a high efficient EGR cooler that has been upgraded with both the optimized wavy cooling fins and the improved shape of structure. The evaluation of the heat exchange efficiency, outlet temperature, and gas pressure drop of the EGR cooler is performed with the prototype of the proposed EGR cooler. The result shows a good solution and will be implemented to the model of a clean diesel engine being developed for both domestic and overseas market.

• Journal of Sensor Science and Technology
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• v.14 no.3
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• pp.198-205
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• 2005

Recently, the systems using multiple sensors such as magnetic, acoustic and pressure sensor are used for detection of underwater objects or vehicles. Those systems have difficulty of maintenance and repair because they operate underwater. Thus, this paper describes a hybrid detection system with long term operating reliability. This has a multi-signal transmission structure to have a high reliability. First, a signal transmission & receiving part, which transfers data from underwater sensors to land and receive control message from land through optical cable, has 4 multi-path. Second, the nodes for signal transmission are connected dually each other with single-hop construction and sensors are connected to a couple of neighboring nodes. This enables the output signal to transmit from a node to the next node and the next but one node together. Also, the signal from a sensor can be transmitted to two nodes at the same time. Therefore, the system with this construction has high reliability in long term operation because it makes possible to transmit sensor data to another node which works normally although a transmission node or cable in system have some faults.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.714-719
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• 1996

Changes in physicochemical properties of brown rice (Chu-chunk byeo, Japonica type) kept at $4^{\circ}C,\;20^{\circ}C,\;30^{\circ}C\;and\;40^{\circ}C$ in laminated film (4 layer) pouches were analyzed. Hardness of brown rice grain increased during storage periods. In case of color changes, 'L' value increased during storage below $30^{\circ}C$, and decreased after three months at $40^{\circ}C$. The 'a' value did not change below $30^{\circ}C$, but increased at $40^{\circ}C$. The 'b' value increased under all storage conditions. Percent germination was above 97% below $20^{\circ}C$ regardlesss of storage period and was inhibited by heat above $30^{\circ}C$. The rice did not germinate after one month storage at $40^{\circ}C$ Gelatinization enthalpy and gelatinization peak temperature by DSC of brown rice powder decreased during storage. As a result, storage below $20^{\circ}C$ in laminated film pouch is recommended far brown rice.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.4
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• pp.210-216
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• 2009

Stainless steel EGR cooler of diesel engine is widely used to prevent the corrosion due to the content of sulfur in diesel fuel. The strength of brazed joint between stainless steel materials is very important. It is essential to observe the spreading ratio of the filler metals under the condition of deoxidation or vacuum during heating process. In this experiment, spreading ratio was tested to find the optimum brazing condition for stainless steel using brazing filler metals of FP-613, BNi-2 and BNi-5 on sus304 and sus410. Anti-corrosion tests were also performed on the above filler metals with solution of 5% $H_2SO_4$, 65% $HNO_3$ and 5% $NH_4OH$. Consequently FP-613 has good ability for anti-corrosion with 30% of chromium content compared with other filler metals. The optimum brazing conditions are occurred at $960^{\circ}C$ for 90 min. and at $1090^{\circ}C$ for 50 min. at the same degree of vacuum, $2{\sim}3{\times}10^{-3}$ Torr.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.703-711
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• 2018

A preliminary design tool of a hypersonic Ludwieg tube facility which simulates real-flight environment was developed and its performance was verified by CFD(Computation Fluid Dynamics) calculations. The operating theory of Ludwieg tube was studied to develop the preliminary design tool. Using the preliminary design tool, Ludwieg tube specifications were determined to satisfy target performance. The Ludwieg tube which produces high speed flows(the Mach number ranging 4 to 10) was designed. Especially altitude simulation at Mach 4 flow could be performed.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.139-147
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• 2007

In military transportation, the use of wide trailer for transporting the large and heavy weight equipments such as tank, armoured vehicle, and mobile gunnery is quite common. So, the vulnerability of causing traffic accidents for these wide military trailer to bump or collide with another car in adjacent lane is very high due to its broad width in excess of its own lane's width. Also, the possibility of these strayed accidents can be increased especially by the careless driver. In this paper, the recognition system of lane and vehicle headway direction is developed to detect the possible collision and warn the driver to prevent the fatal accident. In the system development, Kalman filtering is used first to extract the border of driving lane from the video images supplied by the CCD camera attached to the vehicle and the driving lane detection is completed with regression analysis. Next, the vehicle headway direction is recognized by using neural network scheme with the extracted parameters of the detected driving lane feature. The practical experiments for the developed system are also carried out in the real traffic road of Seoul city area and the results show us the more than 90% accuracy in recognizing the driving lane and vehicle headway direction.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.277-285
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• 2020

Survivability in a battle field is the most important aspect to the warriors. To analyze the survival effectiveness of warrior platform, the simulation via war-game model is an essential step in advance to the development of platform. In this study, Army Weapon effectiveness Analysis Model(AWAM) was utilized for analysis. Several weapon parameters were adjusted to apply the characteristics of warrior platform in some cases of the defense and survival system. Especially, adjusted triage possibility, probability of kill, fatality and accuracy were employed as parameters in the simulation program to evaluate the survival effectiveness of intelligent system based on the previous researches. In the future battle field or virtual space in the AWAM, the warrior platform intelligent system could react emergency treatment on time by expoiting the bio-information of man at arms. Considering the order of supply priority, special force was selected as operating troops and battle scenario without engagement was selected to measure accurate survival effectiveness. In conclusion, the survivability of defence and survival system of the warrior platform was about 1.47 times higher than that of current system.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.107-115
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• 2015

A fine is defined to the criminal penalty which is slighter than imprisonment on a system of criminal penalty, but put practically a seat to imprisonment and similar strong discipline contrivance to commission agent in capitalism societies be doing. Also, did heavy commission, but the corporation time, a fine to consider the respect which cannot impose other criminal penalty, and cannot but impose fine penalty only to this corporation carries out art as important criminal penalty than the commission which a person does. But fine drawing of our country cannot carry out art scaring to criminal penalty to rich body as aggregate fine drawing, and a lot of, but do abatement duration of a fine so as same, and be most in spite of adjudication criminal sentence occupying at criminal case adjudication, and difference cannot do to an amount of a fine that is carrying well out the art. Therefore, and have to change to the daily fine systemdm which gained because of total fine system in order to carry out value as modern criminal penalty, and a few fines shall exchange to penalty payment system according to complement department canon of Penal Code, and social accusation protects individual information of low commission agent if so, can normally do art accomplishment of criminal penalty. The system that the maximum can guarantee right of defence of accused has to have to be introduced in procedural a few aspect to pronounce this and a fine. Specially, let explain necessary fact to be related to, and informal procedures understand, and introduction of drawing to be able to get from accord of accused is necessary for accused before charging to informal decree in order cannot be guaranteed right of defence this of accused while consisting in writing of whether accusation and adjudication are procedural at informal procedures, and to supplement respect.

• Journal of Powder Materials
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• v.22 no.6
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• pp.426-431
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• 2015

Microstructural examination of the Nb-Si-B alloys at Nb-rich compositions is performed. The Nb-rich corner of the Nb-Si-B system is favorable in that the constituent phases are Nb (ductile and tough phase with high melting temperature) and $T_2$ phase (very hard intermetallic compound with favorable oxidation resistance) which are good combination for high temperature structural materials. The samples containing compositions near Nb-rich corner of the Nb-Si-B ternary system are prepared by spark plasma sintering (SPS) process using $T_2$ and Nb powders. $T_2$ bulk phase is made in arc furnace by melting the Nb slug and the Si-B powder compact. The $T_2$ bulk phase was subsequently ball-milled to powders. SPS is performed at $1300^{\circ}C$ and $1400^{\circ}C$, depending on the composition, under 30 MPa for 600s, to produce disc-shaped specimen with 15 mm in diameter and 3 mm high. Hardness tests (Rockwell A-scale and micro Vickers) are carried out to estimate the mechanical property.

• Korean Journal of Remote Sensing
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• v.27 no.3
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• pp.213-223
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• 2011

The purpose of this study is to estimate the spherical wave parameters that appears in synthetic aperture radar (SAR) image acquired over the coast of Chukk, Micronesia. The retrieval of ocean wave parameters consists of two main stages: the first is to determine the dominant wavelengths by Fast Fourier Transform (FFT) over 16 sub-image areas and the second is to estimate wave slopes and heights using dispersion relationship under various water wave conditions. It is assumed that the spherical waves are linear and progressive. These type of waves have the range and azimuth components traveling in radial directions. The azimuth travelling waves are more affected by the velocity bunching mechanism and it is difficult to estimate the wave parameters for these affected areas in SAR imagery. In order to compensate these effects, the velocity bunching ratio (VBR) based on modulation transfer function (MTF) was compared with the intensity ratio for neighbor area in the radial direction in order to assign the spherical wave properties for azimuthally travelling waves. Dispersion relation provides the good estimates for the wave heights for all the selected sub-image areas in the range of 1m to 2m. VBR based on MTF was found to be 0.78 at wave height of 1.36m, while the intensity-based VBR was 0.69 which corresponds to the height of 1.75m. It can be said that the velocity bunching accounts for azimuthally travelling spherical waves and the difference results from the sea-bottom effects.