• 한국조경학회지
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• 제44권6호
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• pp.120-136
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• 2016

본 연구는 경관의 색채를 시간의 개념을 포함하는 연속적 지각의 시퀀스로 보고, 그 흐름과 데이터를 정량적으로 분석하는 기법과 그것을 활용하여 개방성에 따른 도시색채 변화경향을 연구한 것이다. 이는 매우 경험자의 체험에 근접한 리듬으로 대구시 도시철도 3호선인 모노레일 속에서 바라다보는 도시의 색채 시퀀스를 좌우 양쪽에서 동영상을 촬영하여 2초 간격의 프레임에서 대표색 데이터와 시각량을 산출하여 색상, 명도, 채도, 고채도 분포로 시퀀스 데이터를 분석하는 기법들을 도출하였다. 공간의 개방성, 밝기 정도, 선명도 정도, 고채도 분포와 코드, 시각량의 우위, 지배적 노출인자, 한난색의 이미지, 각 세분별 시퀀스 리듬의 다이나믹 정도를 비교 분석할 수 있는 기법을 도출하였으며, 도출된 시퀀스 데이터 중 하늘의 시각량으로 공간 개방도를 결정하고, 개방도에 따른 도시 색채의 경향을 회귀분석하였다. 도시색채는 개방도가 높아질수록 명도는 낮아지고, 채도는 미세하게 증가하였으며, 한색계열이 현저하게 증가하였다. 이는 또한 린치의 공간 위요비례와도 매우 관계가 깊었으며, 도시 색채변화경향을 실제 경관을 통해 더 구체적으로 파악할 수 있었다.

• 천문학회보
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• 제38권2호
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• pp.70.2-70.2
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• 2013

We present collections of optical photometry for a pre-main sequence star HBC 722. It showed large amplitude optical outburst (${\Delta}V=4.7$ mag) in 2010 and classified as a FU Orionis type object. We have been observing HBC 722 from 2011 April to 2013 May, using Camera for QUasars in EArly uNiverse (CQUEAN) attached to the 2.1 m Otto Struve telescope at the McDonald Observatory. Time-series monitoring data (minute-scale interval) were obtained in SDSS r, i and z bands to see short-scale behaviors as well as trace the long-term brightness changes after the eruption in 2010. Interestingly, it started to brighten from 2011 early summer and became brighter than the first outburst peak in our 2013 May observation. We expect that the recovering phase would result from re-increase of disk accretion rate, might attribute to distinctive short-scale color features. In this presentation, we report long- and short-timescale optical behaviors of HBC 722 in the post-outburst phase.

• 한국주거학회논문집
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• 제13권3호
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• pp.61-69
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• 2002

This research is to analyze the spatial organization of a traditional rural community and its characteristics, the case of Hanbam village located in the north of Daegu city. The conclusions of this study are as follows; 1. The difference between private space and public space in the residential area of Hanbam village is obvious, and these two spaces are organically related each other by means of road. These spaces have some spatial characteristics of organization, such as center, hierarchy and sequence. 2. The private space consists of a residence module and a farming area in the settlement, and it is clearly farmed by the firm fence of rocks and by surrounding roads. Fruit-bearing trees such as Pyrus pyrifolia, Cornus officinalis, Diospyros kaki, Juglans sinensis are planted at the boundary. And most of residences are composed of a building, a inner court and farming fields. 3. The public space for the community mainly functions as ‘a meeting place’for residents, and consists of recreational spaces, ceremonial spaces, community facilities, and social facilities. Among these, Jeong-ja(pavilion), Seong-an Soop(forest) and Dae-chong(building for common use) are of great cultural value as important traditional spaces. 4. Two kinds of road are commonly fecund in the village; spontaneously generated one and planned one. This is straight inner streets and access paths to the village, and that is curvilinear alleys which are connected to Dae-chong, the core of village. Also stone walls and climbing plants on them are major elements of village landscape.

• Journal of Power Electronics
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• 제18권2호
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• pp.522-532
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• 2018

The cascaded H Bridge (CHB) multilevel inverter (MLI) is popular among the classical MLI topologies due to its modularity and reliability. Although space vector modulation (SVM) is the most suitable modulation scheme for MLIs, it has not been used widely in industry due to the higher complexity involved in its implementation. In this paper, a simple and novel generalized SVM algorithm is proposed, which has both reduced time and space complexity. The proposed SVM involves the generalization of both the duty cycle calculation and switching sequence generation for any n-level inverter. In order to generate the gate pulses for an inverter, a generalized switch matrix (SM) for the CHB inverter is also introduced, which further simplifies the algorithm. The algorithm is tested and verified for three-phase, three-level and five-level CHB inverters in simulations and hardware implementation. A comparison of the proposed method with existing SVM schemes shows the superiority of the proposed scheme.

• 천문학회보
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• 제39권2호
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• pp.93.1-93.1
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• 2014

The reflection nebula NGC 7023 is a typical example of a photodissociation region (PDR), which consists of high density molecular gas that is exposed to an intense UV radiation field. The source of the UV photons in NGC 7023 is the young pre-main-sequence Be star HD 200755. We present our near-infrared high-resolution (R ~ 40,000) spectrum of NGC 7023, covering a region of $1{\times}15$ arcseconds, observed during the commissioning runs of IGRINS (Immersion GRating near-INfrared Spectrometer). The spectrum shows many strong narrow emission lines that arise from the molecular rovibrational transitions of H2. From the intensity ratios between these H2 lines, we investigate physical conditions within the PDR such as the temperature, density, and pressure. The high spectral resolution of IGRINS allows us to resolve the velocity field of the PDR. In addition, we compare the IGRINS spectrum to Cloudy PDR model.

• Journal of Positioning, Navigation, and Timing
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• 제9권2호
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• pp.43-50
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• 2020

In this paper a low power Spreading Code Authentication (SCA) sequence with a BPSK(1) modulation at a frequency offset of +7.161 MHz is tested for authentication purposes, the Galileo E1OS is used as base signal. The tested signals comprise a Galileo constellation with 5 satellites including the Galileo OS Navigation Message Authentication (OSNMA) and a low power offset BPSK (OBPSK(7,1)) as SCA component. The signals are generated with the software based MuSNAT-Signal-Generator. The generated signals were transmitted Over-The-Air (OTA) using a Software-Defined-Radio (SDR) as pseudolite. With a real-environment-testbed the performance of the SCA in real channel conditions (fading and multipath) was tested. A new SCA evaluation scheme is proposed and was implemented. Under real channel conditions we derive experimental threshold values for the new SCA evaluation scheme which allow a robust authentication. A Security Code Estimation and Replay (SCER) spoofing attack was mimicked on the real-environment-testbed and analyzed with the SCA evaluation scheme. It was shown that the usage of an OBPSK is feasible as an authentication method and can be used in combination with the OSNMA to improve the authentication robustness against Security SCER attacks.

• 충청수학회지
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• 제29권1호
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• pp.73-82
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• 2016

The utility of exponential generating functions is that they are relevant for combinatorial problems involving sets and subsets. Sequences of polynomials play a fundamental role in applied mathematics, such sequences can be described using the exponential generating functions. The actuarial polynomials ${\alpha}^{({\beta})}_n(x)$, n = 0, 1, 2, ${\cdots}$, which was suggested by Toscano, have the following exponential generating function: $${\limits\sum^{\infty}_{n=0}}{\frac{{\alpha}^{({\beta})}_n(x)}{n!}}t^n={\exp}({\beta}t+x(1-e^t))$$. A linear functional on polynomial space can be identified with a formal power series. The set of formal power series is usually given the structure of an algebra under formal addition and multiplication. This algebra structure, the additive part of which agree with the vector space structure on the space of linear functionals, which is transferred from the space of the linear functionals. The algebra so obtained is called the umbral algebra, and the umbral calculus is the study of this algebra. In this paper, we investigate some umbral representations in the actuarial polynomials.

• Journal of Communications and Networks
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• 제5권3호
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• pp.187-196
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• 2003

We consider the use of error control coding in direct sequence-code-division multiple access (OS-COMA) systems that employ multiuser detection (MUO) and space diversity. The relative performance gain between Reed-Solomon (RS) code and convolutional code (CC) is well known in [1] for the single user, additive white Gaussian noise (AWGN) channel. In this case, RS codes outperform CC's at high signal-to-noise ratios. We find that this is not the case for the multiuser interference channel mentioned above. For useful error rates, we find that soft-decision CC's to be uniformly better than RS codes when used with DS-COMA modulation in multiuser space-time channels. In our development, we use the Gaussian approximation on the interference to determine performance error bounds for systems with low number of users. Then, we check their accuracy in error rate estimation via system's simulation. These performance bounds will in turn allow us to consider a large number of users where we can estimate the gain in user-capacity due to channel coding. Lastly, the use of turbo codes is considered where it is shown that they offer a coding gain of 2.5 dB relative to soft-decision CC.

• 천문학회보
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• 제37권2호
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• pp.240.1-240.1
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• 2012

We performed simultaneous observations of SiO v=1, 2, $^{29}SiO$ v=0, J=1-0 and $H_2O$ $6_{16}-5_{23}$ maser lines toward 252 OH/IR stars using the Korean VLBI Network 21m telescopes. The observations were carried out from 2011 November to 2012 July for studying SiO and $H_2O$ maser properties associated with the evolutionary stages of OH/IR stars. Both $H_2O$ and SiO masers were detected from 49 sources, one-side maser of SiO and $H_2O$ was detected from 109 and 11 sources, respectively. Mutual relations between SiO and $H_2O$ maser properties are investigated based on statistical analyses. We also investigate these maser properties in the IRAS two-color diagram related with stellar evolutionary sequence.

• 전력전자학회논문지
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• 제7권1호
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• pp.1-10
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• 2002

본 논문에서는 2상 인버터용 공간전압벡터 PW 방식을 제안하였다. 제안된 2상 공간전압벡터 PWM 방식은 2상 유도전동기에 적용할 수 있다. 2상 공간전압벡터 방식을 사용하는 2상 인버터는 4개의 공간 전압벡터를 발생하나 영 전압 벡터는 만들 수 없다. 2상 인버터에서는 4개의 공간 전압벡터를 조정하여 기본 전압벡터를 실현한다. 또한, 2상 공간전압벡터방식에 의해 최적의 PWM 전압파형을 만들기 위한 대칭변조방식이 제안되었다. 제안된 2상 공간 전압벡터방식에 대한 타당성을 확인하기 위해 시뮬레이션과 실험이 실행되었다.