• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.20-28
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• 2014

In this paper, based on the characteristics of proportional navigation, a composite guidance law is proposed for impact angle control of passive homing missiles maintaining the lock-on condition of the seeker. The proposed law is composed of two guidance commands: the first command is to keep the look angle constant after converging to the specific look angle of the seeker, and the second is to impact the target with terminal angle constraint and is implemented after satisfying the specific line of sight(LOS) angle. Because the proposed law considers the seeker's filed-of-view(FOV) and acceleration limits simultaneously and requires neither time-to-go estimation nor relative range information, it can be easily applied to passive homing missiles. The performance and characteristics of the proposed law are investigated through nonlinear simulations with various engagement conditions.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.2
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• pp.189-197
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• 2014

This work proposes a 12b 100 MS/s $0.11{\mu}m$ CMOS three-step hybrid pipeline ADC for high-speed communication and mobile display systems requiring high resolution, low power, and small size. The first stage based on time-interleaved dual-channel SAR ADCs properly handles the Nyquist-rate input without a dedicated SHA. An input sampling clock for each SAR ADC is synchronized to a reference clock to minimize a sampling-time mismatch between the channels. Only one residue amplifier is employed and shared in the proposed ADC for the first-stage SAR ADCs as well as the MDAC of back-end pipeline stages. The shared amplifier, in particular, reduces performance degradation caused by offset and gain mismatches between two channels of the SAR ADCs. Two separate reference voltages relieve a reference disturbance due to the different operating frequencies of the front-end SAR ADCs and the back-end pipeline stages. The prototype ADC in a $0.11{\mu}m$ CMOS shows the measured DNL and INL within 0.38 LSB and 1.21 LSB, respectively. The ADC occupies an active die area of $1.34mm^2$ and consumes 25.3 mW with a maximum SNDR and SFDR of 60.2 dB and 69.5 dB, respectively, at 1.1 V and 100 MS/s.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.1020-1027
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• 2008

In this paper, the refraction angles and the critical angles of metamaterials which is assumed by the Drude model are analytically studied. To analyze the electromagnetic reflection and the transmission properties of metamaterial slab, we used "-1" for the permeability and the permittivity at 30 GHz in Drude model for metamaterials in this paper, respectively. Due to the variation of signes of material constants for frequency ranges in Drude model, the derived refraction angle and the critical angles for each frequency ranges are differently observed. The results in this paper show that the properties the refraction angles and the critical angles for the broadband in metamaterials can be used to understand the electromagnetic properties of metamaterials and microwave applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1384-1393
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• 2008

In this paper, we analyzed the multilayer structure with lossy metamaterials using ABCD Matrix method to get the transmission characteristics. Compared to the recursive method which cannot be used to analyze the lossy characteristics of multilayer structure because of its complexity, we used the ABCD matrix method is easy to apply because of its matrix chain concepts for arbitrary number of multilayer structure and lossy material. To verify the results of this paper, we used both for multilayer dielectric and metamaterial, respectively, and obtained the same results. Multilayer structure with lossy metamaterial showed minimized ripple and broadband transmission compared to dielectric multilayered structure. This can be used in various applications as antenna radome and shielding material, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.471-479
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• 2020

In this paper, we analyze features of radical innovative businesses using their patents. Although patents have been used to evaluate outcomes of businesses from the 1980s, it is challenging to use patents for radical innovations. We examined the possibility of taking advantage of patents for an indicator that represents a radical innovation in pharmaceutical industry. To this end, we collected FDA approval data from the U.S. Food and Drug Administration and patent data of 18 pharmaceutical companies. For analysis, we utilized the network centrality analysis and Wilcoxon signed ranked test, which is a non-parametric statistical hypothesis test used to compare two related samples. We observed that a radical innovative company typically cooperates with other research groups, such as universities and companies, and acts as a hub for connectivity in pharmaceuticals. Also, we found that there are differences in centrality between radical firms and non-radical firms. Thus, we expect that the results of this study will help in developing strategies for research and development of pharmaceutical companies and identifying factors affecting radical innovation in the future.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.533-540
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• 2014

We propose an age estimation-based smart digital signage for the next-generation airport service. The proposed system can recognize the face of the customer so that it can display the selective information. Using a webcam, the system captures the face of the customer and estimates the age of the customer by calculating the wrinkle density of the face and applying bayesian classifier. The developed age estimation method is tested with a face database for the performance evaluation. We expect the new digital signage may improve the satisfaction of customers of the airport business.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.959-970
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• 2004

It has become more difficult to correspond an cyber attack quickly as patterns of attack become various and complex. However, current so curity mechanisms just have passive defense functionalities. In this paper, we propose new network suity architecture to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed architecture makes it possible to deal effectively with cyber attacks such as IP spoofing or DDoS(Distributed Denial of Service), by using active packet technology including a mobile code on active network. Also, it is designed to have more active correspondent than that of existing mechanisms. We im-plemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.69-81
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• 2008

It has become more difficult to correspond a cyber attack quickly as patterns of attack become various and complex. However, current security mechanism just have passive defense functionalities. In this paper, we propose new network security mechanism to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed mechanism makes it possible to deal effectively with cyber attacks such as IP spoofing, by using active packet technology including a mobile code on active network. Also, it is designed to hove more active correspondent than that of existing mechanisms. We implemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.

• Convergence Security Journal
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• v.13 no.2
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• pp.195-202
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• 2013

Defense reform our military for the globalization of information. Scientific command structure, troop structure, unit structure, step-by-step into the power structure while promoting a history of quantitative-oriented structure, and structure of the quality of state-of-the-art technology-driven transition in the middle of the bottle numberplans about the current 3.3-fold increase in reducing the cadre(officers and NCOs). NCO groups in the executive, especially expanding the current level of 100% increase in the rate of long-serving, while ensuring a stable job and to superior resources to secure a stable policy through science. Military alliance is now underway. In the midst of this group, and urged the group at the University of the leading military and specialized resources to ensure each agreement required by subjects to reflect. Thus effectively improve the quality of education and the demands of the job analysis, DACUM curriculum development methods and procedures can be applied at the time of urgent need for foster an excellent resource for the discharge of curriculum development at the University of Selected as a core job, career, and job classification configuration inside of Duty according to KST derived from the group reflect on the training courses to meet the requirements in the curriculum through the development of curriculum, job definition, job model set to propose.

• Molecules and Cells
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• v.39 no.3
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• pp.250-257
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• 2016

Abiotic stresses such as drought and low temperature critically restrict plant growth, reproduction, and productivity. Higher plants have developed various defense strategies against these unfavorable conditions. CaPUB1 (Capsicum annuum Putative U-box protein 1) is a hot pepper U-box E3 Ub ligase. Transgenic Arabidopsis plants that constitutively expressed CaPUB1 exhibited drought-sensitive phenotypes, suggesting that it functions as a negative regulator of the drought stress response. In this study, CaPUB1 was over-expressed in rice (Oryza sativa L.), and the phenotypic properties of transgenic rice plants were examined in terms of their drought and cold stress tolerance. Ubi:CaPUB1 T3 transgenic rice plants displayed phenotypes hypersensitive to dehydration, suggesting that its role in the negative regulation of drought stress response is conserved in dicot Arabidopsis and monocot rice plants. In contrast, Ubi:CaPUB1 progeny exhibited phenotypes markedly tolerant to prolonged low temperature ($4^{\circ}C$) treatment, compared to those of wild-type plants, as determined by survival rates, electrolyte leakage, and total chlorophyll content. Cold stress-induced marker genes, including DREB1A, DREB1B, DREB1C, and Cytochrome P450, were more up-regulated by cold treatment in Ubi:CaPUB1 plants than in wild-type plants. These results suggest that CaPUB1 serves as both a negative regulator of the drought stress response and a positive regulator of the cold stress response in transgenic rice plants. This raises the possibility that CaPUB1 participates in the cross-talk between drought and low-temperature signaling pathways.