• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.1-7
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• 1995

A IR zoom telescope system was designed for thermal imagery. The magnification is 4-14 and the focal length of eye piece is 25 mm. First, the frame was built up with first order optics and started design with 3rd order optics. There after, we can get the final design by optimization technique through finite ray tracing. The optical system was optimized with ray aberration or angular aberration including higer orders. Finally, The performance of the optical system was accessed by calculating the diffraction MTF from the design data. data.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.26-35
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• 2004

As part of thrust control technology research on turbopump-fed type liquid-propellant rocket engine system, the low frequency dynamic characteristics of turbopump was investigated. It can be described that a turbopump system has a 1st-order lag element. When the value, which was resulted by subtraction of the variation of turbine moment with respect to the variation of revolution number from the variation of pump moment with respect to the variation of revolution number, was positive, the time constant of the 1st-order lag element was positive which stood for a stable system. Increasing the above-mentioned valve within positive range leaded to the increase of response and to the decrease of controllability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.301-306
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• 2000

Small passenger and car carrier ships are mainly used as a connection way between land and small islands. And these ships should be designed to enlarge the capacity of passenger and car loading within limited space and draft. So the resonances of various vibrations exist in normal operation range of engine and propulsion shafting. In this paper, hull's superstructure vibration which was especially induced by the 1st order excitation of whirling vibration on the 2-engines and 2-propulsion shafting systems is introduced. Also these are verified via the theoretical analysis using transfer matrix method and FEA software ANSYS and its vibration measurement.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.2
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• pp.187-196
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• 2021

The Network-Centric warfare over weapon data link networks has been developed for the recent decade. Since the US navy had begun to develop tactical digital information chain, it has gradually transformed into weapon data link technology. As data link network system and its protocol have been advanced into high-technology, focusing and targeting on moving targets become possible in net-enabled environments. However, it is difficult to identify the primary information from numerous battlefields and understanding approaches to damage a target in a timely manner. In this paper, to better understand the targeting assessment, we suggest a specific solution: Bomb Hit Indication(BHI) using information in weapon data link messages. In order to prove our suggestion, we implement the BHI solution and apply it into the weapon data link integrating system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.43-49
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• 2005

Temperature stabilities of resonance frequencies of the substrates are very important in piezoelectric ceramics oscillators and fitters. In this study, it was investigated thermal resisting property of the length-extensional vibration mode of PZT ceramics. The mode can be utilized in fabricating ultra-small 55 kHz IF devices. We fabricated the ceramic specimens with x = 0.51, 0.52, 0.53, 0.54, and 0.55 in the Pb(Zr$\sub$x/Ti$\sub$1-x/)O$_3$ system. And their resonance frequencies were measured before 1st thermal aging, after 1st and 2nd thermal aging. In order to investigate the influence of thermal aging on thermal resisting properties, thermally aged specimens were once mote thermally aged. Before 1st thermal aging, the specimens of the compositions with morphotropic phase, x = 0.53 and rhombohedral phase, x = 0.54 have weak thermal resisting property of resonance frequency, while tetragonal phase, x = 0.51 has robust thermal resisting property of resonance frequency. 1st thermal aging improved thermal resisting property of resonance frequency in all specimens.

• Journal of Korea Multimedia Society
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• v.22 no.7
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• pp.815-821
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• 2019

This paper presents the design and implementation of a Mission Planning System(MPS) for multiple ballistic missiles. MPSs are also a kind of M&S systems in defense domain, and these provide important computations on the ground before flights of flying objects. The proposed MPS in this paper has a new concept which is far from generating a set of waypoints of a flying object and proving the set. In this paper, we firstly discuss the research motivation of our own MPS; then, we introduce the design of our MPS and its functionalities. In order to prove the practicality of our MPS, we have conducted a case study.

• Journal of Korean Association for Spatial Structures
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• v.19 no.1
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• pp.53-64
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• 2019

The objective of this study is to investigate the earthquake response for the design of 100m spanned single-layer lattice dome. The plastic hinge analysis and eigenvalue buckling analysis are performed to estimate the ultimate load of single-layered lattice domes under vertical loads. In order to ensure the stability of lattice domes, it is investigated for the plastic hinge progressive status by the pushover increment analysis considering the elasto-plastic connection. One of the most effective methods to reduce the earthquake response of large span domes is to install the LRB isolation system of a dome. The authors discuss the reducing effect for the earthquake dynamic response of 100m spanned single-layered lattice domes. The LRB seismic isolation system can greatly reduce the dynamic response of lattice domes for the horizontal and vertical earthquake ground motion.

• Journal of Environmental Health Sciences
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• v.19 no.4
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• pp.14-24
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• 1993

The present study was accomplished from October, 1992 to June, 1993 in order to examine the seasonal community structure of aquatic insects and the biological estimation of water quality by the aquatic insects of the Jungneung and Gokneung streams in the Mt. Bukhan. The obtained results are as follows: 1. The total taxa of aquatic insects appeared as 77 species, 45 genera, 28 families in 7 orders. 2. Seasonal occurrence species numbers showed the highest in the autumn of the Jungneung stream (19 species) and in the spring of the Gokneung stream (41 species). Seasonal occurrence individual numbers showed the highest in the summer of the Jungneung and Gokneung streams (5,901, 3,180 individuals) and the lowest in the autumn of Jungneung stream (612 individuals) and in the winter of the Gokneung stream (1,764 individuals). 3. Annual dominance indices showed 0.52 (stJ1)~1.00 (st.J3) range in the Jungneung stream, and 0.47 (st. G1)~0.76 (G2) range in the Gokneung stream. 4. Seasonal species diversity indices showed 0.00 (st J3, whole seasons)~3.12 (st.J1, Spring) range in the Jungneung stream and 0.69 (st. G2, summer) ~3.10 (st. G4, spring) in the Gokneung stream. 5. Biological saprobic system based on species diversity indices of aquatic insects appeared as oligosaprobic area: site J3, $\alpha$-mesosaprobic area: site J2, G2, G3 and $\beta$-mesosaprobic area: site J1, G1, G4.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.347-356
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• 1997

Solution copolymerization of Styrene(St) and n-Butylmethacrylate(BMA) was carried out with Benzoylperoxide (BPO) as an initiator in toluene at $80^{\circ}C$ in a continuous stirred tank reactor. Reaction volume and residence time were 0.6 liters, 3 hours respectively. The monomer reactivity ratios, $r_1$(St) and $r_2$(BMA) were determined by both the Kelen-Tlidos method and the Fineman-Ross method ; $r_1$=0.75(0.67), $r_2$=0.61(0.56). The cross-termination factor, $\phi$ factor of the copolymer over the entire St compositions ranged from 0.44 to 0.78. The $\phi$ factors of St-BMA copolymer increased with increasing St compositions. Our present system showed that the continuous copolymerization of St with BMA followed second-order kinetic behavior. The simulated conversions and copolymerization rates were compared with the experimental results. The average time to reach dynamic steady-state was three times and half of the residence time.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.404-412
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• 2014

We proposed a design method for squib current supply & interlock circuits in guided-missile fire control systems. In order to design squib current supply circuits, various missile squib loads including line resistance and squib devices have to be considered in advance minimizing probability of redesign of circuits and reducing the development cost by implementing the most proper squib current supply circuit. Also, we presented a hardware interlock logic instead of the commonly used software safety logic to improve the safety of guided-missile fire control systems. The proposed squib interlock circuit enhances safety requirements of guided-missile fire control systems. We confirmed that simulation and measurement results of the proposed design method are the same as theoretical analysis results.