• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.243-246
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• 2006

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyre-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyre-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.179-182
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• 2008

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyro-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.255-263
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• 2017

An infrared-guided missile has been emerging as a major threat against combat aircraft due to its passive guidance characteristics and with recent advances in stealth technology. Hence, the infrared stealth technology and its effectiveness-evaluation technique become more significant than ever before. In this study, we applied missile aerodynamics to lethal range calculation which allowed more precise prediction. CFD analyses were newly involved in estimating drag force characteristics of an infrared-guided missile. Velocity profiles during flight period of the missile were constructed utilizing these drag characteristics and then incorporated into our in-house code to predict corresponding lethal ranges. The results showed that the present method can predict lethal range more appropriately than the previous one with constant velocity profile. As one of the results, if a fighter gains altitude more which reduces less drag of the attacking missile, then the lethal envelope increases significantly more compared to the lock-on envelope.

• Journal of Korea Soil Environment Society
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• v.2 no.3
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• pp.81-88
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• 1997

The purpose of this study is to assess contaminant transfer and environmental impacts to the surroundings by inadequate control of USTs. Several methodologies can be used in sampling procedure for the site assessment depending on the appearance of contaminants on the site and their types. In this case study because of site contaminants, randomized and/or triangle matrix techniques were used. As a result, the composition of materials in OO gas station were appeared in several status. From 1 to 2.5m depth, the soil was composed of silty sand and gravel, around 4m depth, weathered rock was appeared. Based on the preliminary and actual site investigation by DPT methodologies on the width and depth of the site with analysis of BTEX and TPH, no contamination was found in OO gas station, however, in one point because of careless dumping after refill by oil company, about 1731. 5 ppm of TPH appeared.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.891-899
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• 2006

Generally, a geographical area consists of many regions called cells in wireless networks. Each mobile host(MH) in a cell communicates with a base station(BS) located in the center of the cell. The BSs are connected to each other by a static wired network. Since users are expected to move around during communication sessions, one of the most important QoS factors is related to the handoff. But, the handoff could fail due to unavailability of sufficient bandwidth in the next cell. As the individual cell size gradually shrinks to accommodate increasing the number of MHs, the probability of successful handoffs can be dropped. In this paper, we suppose a bandwidth reservation method to guarantee MHs against connection failure in case of frequent handoffs. This method predicts the mobility based on the geographical information and assigns the bandwidth reservation in proportion to the speed of MHs' motion. As a result, we can expect more exact moving path of MH and to reduce the waste of bandwidth.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.1-4
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• 1998

The ecology of rhizome rot incidence rates between Seosan, Chungnam and Bongdong, Chonbuk province were surveyed in this experiment. The rhizome rot incidence rate of Seosan was lower than that of Bongdong. The average ginger product of former province was 1,140kg, whereas it's 818kg per 10a. in latter province. Treatment after disease incidence frequently used fungicide at Seosan. There were different soil physiological property between fields. Although Eunhari and Yulsori were belong to Bongdong province, incidence rate was low at Eunhari, contained 23% clay and high incidence rate at Yulsori, approximately contained 60% silt. Many soil chemical properties of cultivated area were belong to optimum concentration range, but phosphate(P) was higher than optimum concentration, 450-550ppm. The number of soil fungi in the middle of cultivated season tended to show the highest. Both bacteria and actinomyces` number was similar to the result of fungi. The bacteria/fungi ratio was greatly different between surveyed fields.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.54-62
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• 2012

A Wi-Fi mesh network providing multi-hop wireless connections based on IEEE 802.11 PHY/MAC technology has recently received a significant attention as a network infrastructure that interconnects RFID systems and wireless sensor networks (WSNs). However, the current IEEE 802.11 contention-based MAC protocol cannot fully utilize the network capacity due to eithor frame collisions or unused network resources. In this paper, we propose a novel multi-channel scheduling MAC (MCS-MAC) protocol for Wi-Fi mesh networks. Under the secondary interference model of Wi-Fi mesh networks, the MCS-MAC protocol can maximize the network throughput via activation of collision-free links that has a maximal link weight. Through the simulations, we show that the throughput of the MCS-MAC protocol is at least three times higher than that of existing MAC protocols in Wi-Fi mesh networks.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.435-443
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• 2020

We analyzed whether the use of the Bluetooth salinity meter could affect the proper level of salinity in childcare centers. This study was conducted on childcare centers that wish to participate in the sodium reduction project (Bluetooth salinity meter using group, BG) and those that did not participate (Bluetooth salinity meter not using group, NG) among childcare centers registered with Center for Children's Foodservice Management in Anyang from January to December 2019. As a result of comparing the salinity and sodium contents of the soup according to whether or not a Bluetooth salinity meter was used, the salinity and sodium contents of BG was significantly lower than that of NG (p < 0.0001). Salinity and sodium contents in soups tended to decrease as the number of use of the Bluetooth salinity meter increased (p = 0.020). In conclusion, Bluetooth salinity meter can be used as a means to induce voluntary salinity control by cookers regarding sodium reduction education at childcare centers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.306-309
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• 2017

The development of modern ICT technology constitutes cyber world by using infrastructure in country and society. There is no border in cyber world. Countries around the world are carrying out cyber attacks for their own benefit. A cyber killer strategy is needed to defend cyber attacks. In order to defend the cyber attack or to determine the responsibility of attack, it is important to grasp the attacker origin point. Strategic cyber kill chains are needed to strike against the attacker origin. In this paper, we study the analysis of attacker origin. And analyze the cyber kill chain for attacker origin point strike. Study the efficient and customized cyber kill chain strategy for attacking the origin point. The cyber kill chain strategy will be a practical strategy to replace the power of nuclear and missiles with asymmetric power.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.293-296
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• 2008

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems, it has been invented ball type bolt. The present work was represented quantitively the margin of separation safty and separation mechanism in ball type bolt to analyse the dynamic separation test. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyro-shock. And it also has a good mechanical properties as much as those of explosive bolt.