• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3C
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• pp.329-340
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• 2009

This paper proposes a novel code tracking scheme to track the fine code synchronization for BOC(pn,n) modulated spreading signals. The correlation function of BOC(pn,n) modulated spreading signals has been several peaks. In this paper, we observe that the correlation function in the advanced offset region remains almost unchanged, due to the multipath signals being received later than a line-of-sight signal. Based on this observation, we propose a novel code tracking scheme which is called the advanced region correlation (ARC) method for BOC(n,n) modulated spreading signals. And, we compare with the code tracking accuracy between the conventional and proposed methods in the static multipath and land mobile satellite system channels through the Monte-Carlo simulation. Then, base on the proposed scheme, we propose the generalized-ARC (ARC) scheme for BOC(pn, n) modulated spreading signals.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.332-340
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• 2011

A missile with a strapdown seeker should properly estimate line-of-sight(LOS) rate using its attitude information and the look angle of the seeker because LOS rate information in an inertial coordinate system, which is used for a proportional navigation(PN) homing guidance, can not be obtained directly. However, an unnecessary feedback loop(Parasite Loop) is formed in the guidance and control loop, and it may cause the guidance performance degradation or even the unstability of the system(Parasite Effect). This paper presents estimation methods for the LOS rate information and effective ways to minimize the parasite effect using Routh-Hurwitz stability criterion. Various numerical simulations are also included to verify the proposed methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.965-976
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• 2012

Multi-Platform Image and Intelligence Common data link(MPI-CDL) systems are designed to transmit the imaginary and signal intelligence data at an aeronautical to ground line of sight(LOS) link. This paper proposes a method to predict a link availability and analyzes the required link margin to satisfy a given link availability for MPI-CDL systems. To estimate a link availability the proposed method applies the conditional probability so that both a rain attenuation and a multipath fading are considered simultaneously. Link margins to meet the link availability for MPI-CDL systems are calculated according to an operating environment including frequencies, flight altitudes and transmission ranges. The required link margins for actual unmanned air vehicle systems are also given by simulation results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.292-299
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• 2012

The line-of-sight(LOS) rate is estimated using Kalman filter in Radio-Frequency(RF) seeker. For the two axis gimbaled seeker, proper system modeling is considered and the basic filter structure is set up. The main issue for Kalman filter is choosing the proper process and measurement noise. For the measurement process, the signal to noise ratio(SNR) and other components are introduced. To cope with the eclipse problem or other abnormal seeker status, the pseudo input signal concept is proposed. By conditioning abnormal signals, the LOS rate estimation performance is increased. The process noise is also an important factor in the propagation phase. The analytical approach on a process noise component is performed and a reliable region for the filter is calculated based on the eigenvalue analysis. Some numerical simulations are performed to check the validity of suggested algorithm.

• Convergence Security Journal
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• v.18 no.5_2
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• pp.53-60
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• 2018

As science and technology develops, it is expected that more precise and various weapons will be used in a much more complicate future battlefield environment. C4I is a system that provides the proper and necessary information to commanders and their staffs to recognize the battlefield situation by connecting and visualizing the complex battlefield environment and various weapon systems together. Commanders and staffs perform battle command training based on a computer or paper map to better utilize the C4I system and Command Post eXercise(CPX) is a process of the training. This is the way for them to improve command control and decision making skills. Analyzing of line of sight(LOS), identifying communication fringe area, deploying troop strength, and determining unit maneuver are highly restricted under the 2D based CPX. In recent years, however, three-dimensional (3D) CPX simulators have been developed to overcome these drawbacks. In response to this trend, this paper proposes a multi-user based CPX simulator using augmented reality (AR) glass, which can be used as a practical war game simulator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1210-1230
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• 1997

In this paper, we suggest an architecture of DS/CDMA tranceiver composed of one pilot channel used as reference and multiple traffic channels. The pilot channel-an unmodulated PN code-is used as the reference signal for synchronization of PN code and data demondulation. The coherent demodulation architecture is also exploited for the reverse link as well as for the forward link. Here are the characteristics of the suggested DS/CDMA system. First, we suggest an interlaced quadrature spreading(IQS) method. In this method, the PN coe for I-phase 1st channel is used for Q-phase 2nd channels and the PN code for Q-phase 1st channel is used for I-phase 2nd channel, and so on-which is quite different from the eisting spreading schemes of DS/CDMA systems, such as IS-95 digital CDMA cellular or W-CDMA for PCS. By doing IQS spreading, we can drastically reduce the zero crossing rate of the RF signals. Second, we introduce an adaptive threshold setting for the synchronization of PN code, an initial acquistion method that uses a single PN code generator and reduces the acquistion time by a half compared the existing ones, and exploit the state machines to reduce the reacquistion time Third, various kinds of functions, such as automatic frequency control(AFC), automatic level control(ALC), bit-error-rate(BER) estimator, and spectral shaping for reducing the adjacent channel interference, are introduced to improve the system performance. Fourth, we designed and implemented the DS/CDMA MODEM to be used for variable transmission rate applications-from 16Kbps to 1.024Mbps. We developed and confirmed the DS/CDMA MODEM architecture through mathematical analysis and various kind of simulations. The ASIC design was done using VHDL coding and synthesis. To cope with several different kinds of applications, we developed transmitter and receiver ASICs separately. While a single transmitter or receiver ASC contains three channels (one for the pilot and the others for the traffic channels), by combining several transmitter ASICs, we can expand the number of channels up to 64. The ASICs are now under use for implementing a line-of-sight (LOS) radio equipment.

• Journal of Korean Classical Literature and Education
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• no.15
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• pp.355-387
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• 2008

The purpose of the study was to decide Korean translation and the copying period of "Korean Translation of " and to look all around their characteristics in different versions carefully until now. The "Korean Translation" is a collection of Korean-translated romance and love stories excavated by a professor Kim,Il Geun, and there is not a little meaning in the context of novel history in the point of view of 'Korean translation of a court possession'. Arranging conclusion of the study generally, it is as follows. (1) Considering phonological phenomena, grammar and vocabulary in the study of Korean language, it is presumed that they would be translated into Korean and copied between the regime period of the King Sukjong and the regime period of the King Yungjo in the Joseon Dynasty. For, they were composed of a middle declaration of copied 'Myeoknambon "Korean Translation of Taepyeonggwanggi(태평광기)"' and 'NakseonJaebon(낙선재본)' between the middle of the 17th century and the middle of the 18th century and the regime period of the King Jeongjo in the Joseon Dynasty appointed as the background period of the novels should be excepted. Consequently, through the Korean Translation, we can confirm that the novel scope between the 17th century and the 18th century in Korean novel history was widened until 'The Royal Court' and 'Women'. (2) In the side of vocabulary, the "Korean Translation" also has not a little meaning in the side of a collection translated in the Royal Court. It doesn't have new vocabularies, but partial vocabularies as '(Traces:痕)' '(Clean eyes:明眸)', ' (Sail:帆)', '(Get up:起)', '글이플(Weak grass:弱草)', '쇼록(Owl:? 梟 or 鴉?)', '이 사라심(This life:此生)', and '노혀오매(Look for:訪)' are good data in the study of Korean language. (3) The "Korean Translation" is a valuable data about translation and copying of a court novel and we can discover intentionally changed parts and partially omitted sentences rather in the than in the . There are differences between a translation book and a copying book and we can catch sight of intention of translation and unsettledness of copying in the second work. Therefore, we can know that the "Korean Translation" has a double context which one work is translated and a work in different version is derived, compared to a simple copy. (4) The "Korean Translation" has a close relation with "Hangoldong(閒汨董)", but it doesn't regard the same copy as a foundation. The basic copy of translation of the "Korean Translation" is a different version of the same line as "Hangoldong" and "Jeochobon(저초본:정명기 소장본)" and is more similar line to "Hangoldong", but it is also not the same basic copy. (5) Considering that the "Korean Translation" doesn't has a distinct relation with the "Hangoldong", there is no correlation between the "Korean Translation" and and the "Hangoldong" and . In addition, we could not discover a writer's identity between the two.

• Publications of The Korean Astronomical Society
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• v.12 no.1
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• pp.63-84
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• 1997

We carried out high-resolution(FWHM=3' .3) HI 21 cm observations of the supernova remnant(SNR) PKS0607+17 and HII region S261 using Arecibo 305-m telescope. The observation was to investigate whether the high-velocity(HV) gas detected in the southern area of PKS0607+17 by Koo & Heiles(1991) is physically associated with the SNR or not. The velocity of the HV gas ranges from +64 km/s to +87 km/s, which is difficult to result from the Galactic rotation. The HV gas could be the gas accelerated by supernova blast wave. However, because the observation of Koo and Heiles(1991) was carried out using Hat Creek radio telescope(FWHM $\simeq$ 36'), the association of the HV gas with the SNR could not be investigated. Using the Arecibo HI 21cm data, we have found that the HV gas appears m the southern part of the SNR and its velocity ranges from +61 km/s to +77 km/s. But the HV gas is scattered m the whole field, not only toward PKS0607+17 but also outside the SNR Accordingly the HV gas is probably not associated with the SNR, but is accidentally aligned along the same line of sight toward the SNR. Instead we have found that HI clouds at low velocities could be possibly associated with the SNR. In Arecibo HI 21cm channel maps the HI gas seems to surround the southern boundary of the SNR at $V_{LSR}$ = +19.6 ~ +40.2 km/s. But because the region of the Arecibo HI 21cm observation is not wide enough to examine the HI gas distribution, we investigated this area using the Berkely low-latitude HI survey data(Weaver & Williams 1974) too. There we found HI gas surrounding the radio continuum boundary of PKS0607+17 at $V_{LSR}$ = +21.6 ~ +258 km/s. It is possible that this HI gas is associated with the SNR, in which case, the velocity of the SNR $V_o$ $\simeq$ +26 km/s, its distance d $\simeq$ 12.5 kpc and its radius R $\simeq$ 145 pc. If we assume that the expansion velocity is ~10 km/s, then the age of the SNR is $\sim4.4\times10^6$ years. PKS0607+17 could be one of the oldest SNRs in the Galaxy. We also studied HI propertities of the HII region S261, which is $\sim1^{\circ}$ away from PKS0607+17. There has been no high-resolution m 21 cm observational study on S261. We discovered HI cloud located at the north-eastern part of S261 at $V_{LSR}$ = +5 km/s ~ +10 km/s, which is possibly associated with the HII region. The central velocity of the HI cloud $V_{LSR}$ = +7.2 km/s and the corresponding distance d = 1.5 kpc. This velocity is comparable to the radio recombination line velocities.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.37.2-37.2
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• 2011

Our previous study on tiny pores (R < 2") observed by HINODE/Solar Optical Telescope (SOT) revealed that the plasma in the pores at the photosphere is always moving down and the pores are surrounded by the strong downward motions (highly red-shifted) of neighboring granulations. From this study, we speculated that the flow motions above the pore should be related with the motions at the photosphere, since the pore is strong magnetic field region. Meanwhile, SNU and KASI installed Fast Imaging Solar Spectrograph (FISS) in the Cude room of the 1.6 m New Solar Telescope (NST) at Big Bear Solar Observatory. FISS is a unique system that can do imaging of H-alpha and Ca II 8542 band simultaneously, which is quite suitable for studying of dynamics of chromosphere. To get some clue on the relationship between the photospheric and low-chromospheric motions at the pore region, we took a coordinate observation with NST/FISS and Hinode/SOT for new emerging active region (AR11117) on October 26, 2010. In the observed region, we could find two tiny pores and two small magnetic islands (SMIs), which have similar magnetic flux with the pores but does not look dark. Magnetic flux density and Doppler velocities at the photosphere are estimated by applying the center-of-gravity (COG) method to the HINODE/spectropolarimeter (SP) data. The line-of-sight motions above the photosphere are determined by adopting the bisector method to the wing spectra of Ha and CaII 8542 lines. As results, we found the followings. (1) There are upflow motion on the pores and downflow motion on the SMIs. (2) Towards the CaII 8542 line center, upflow motion decrease and turn to downward motion in pores, while the speed of down flow motion increases in the SMIs. (3) There is oscillating motion above pores and the SMIs, and this motion keep its pattern along the height. (4) As height increase, there is a general tendency of the speed shift to downward on pores and the SMIs. This is more clearly seen on the other regions of stronger magnetic field. In this talk, we will present preliminary understanding of the coupling of pore dynamics between the photosphere and the low-chromosphere.

• Archives of design research
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• v.15 no.1
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• pp.181-190
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• 2002

Every object's patterns is the balancing-relationship between the object's inner-energy and outer-stress. To see this as a balancing-relationship between an organism, inner-energy would be the occurrence of thermodynamic entropy which is for its existing maintenance. Outer-stress would be the friction that comes from the surrounding environment. Namely, we can see that object's figure exists in the balance between an extort to survive and fiction that disturb it. However, it is fourth that these figures are consisted of a curve and curved-surface which is not a straight line. So, it is impossible to find a figure made up of straight lines and surfaces in the existing object's world. It's true that we have regarded only a curve as the beautiful. Here, we have presented that in a curve, there exists an important function which protect our survival from the ancient humanity. And by closely observing the function in a physical dynamic-pattern sight, we've searched what is important in the design's origin that handle curve-patterns. Of course it would be more reasonable to analyze it in the standpoint of Mathematics, Chemistry, or Biology, and synthesize the points. However, due to the limitation of the researchability, we will concern about the physical structure in the design. Deficient details will be replenished through the study between educational systems. As a result, we have confirmed that, devoting the curve's physical structure-phenomenon (occurred in nature) to the design, is more beautiful in our eyes, too.