• Journal of Astronomy and Space Sciences
• /
• 제33권2호
• /
• pp.93-99
• /
• 2016

A redback system is a binary system composed of a pulsar and a main sequence star. The inverse Compton (IC) scattering between the stellar soft photons and the relativistic pulsar wind will generate orbital-modulating GeV photons. We look for these IC emissions from redback systems. A multi-wavelength observation of an unassociated gamma-ray source, 3FGL J2039.6-5618, by Salvetti et al. (2015) detected an orbital modulation with a period of 0.2 days in both X-ray and optical cases. They suggested 3FGL J2039.6-5618 to be a new redback candidate. We analyzed the gamma-ray emission of 3FGL J2039.6-5618 using the data from the Fermi large area telescope (Fermi-LAT) and obtained the spectrum in different orbital phases. We propose that the spectrum has orbital dependency and estimate the characteristic energy of the IC emission from the stellar-pulsar wind interaction.

• 한국철도학회논문집
• /
• 제9권2호
• /
• pp.206-211
• /
• 2006

This thesis presents railroad crew restoring problem, which is to determine the railroad plan allocation. This problem is constructed that determine the sequence of duties that railroad crews have to perform. We analyze characteristic of this problem and railroad industry. It's hard to consider many constraint conditions. We propose Integer Programming model and easy methodology to be considered all given operation rules. This problem is known to be NP-hard. We develop a genetic algorithm, which is proved to be powerful in solving optimization problems. We proposed the effective mathematical model and algorithm about making crew restoring in real industry.

• Animal Systematics, Evolution and Diversity
• /
• 제30권1호
• /
• pp.26-32
• /
• 2014

Cleantioides planicauda (Benedict, 1899) has previously been recorded in China and Japan. In the present study, to our knowledge, we report for the first time the occurrence of this species in South Korea. Here, we provide detailed descriptions and illustrations of the diagnostic characteristics of C. planicauda. Further, for the first time, we determined the partial sequence of mitochondrial cytochrome c oxidase subunit 1 (CO1) gene of C. planicauda for molecular characteristic. Additionally, we provide a key to the Korean species and distribution of the genus Cleantioides. As a result of this study, four species of the genus Cleantioides, including C. planicauda, have now been recorded in South Korea.

• Tribology and Lubricants
• /
• 제19권5호
• /
• pp.274-279
• /
• 2003

$Al-SiC_{p}$ composite layer was prepared by plasma thermal spray on aluminum substrate. The homogeneously dispersed composite powder for thermal spray was fabricated by mechanical alloying with ball mill. The friction tests of the composite layers and commercial aluminum alloys for comparison were performed in the temperature range of 20∼$260^{\circ}C$ with the interval of $40^{\circ}C$ with steel counter-face. Friction coefficient was recorded during test sequence, and the microstructure of surface and debris was investigated by optical and scanning electron microscope. Friction coefficients of composite and aluminum alloys at room temperature were similar except pure aluminum. As the temperature increase, friction coefficient was increased rapidly in AC4C, AC2A. But friction coefficient of $Al-SiC_{p}$ composite was not increased so much up to $220^{\circ}C$. Consequently, the reinforcement of $SiC_{p}$ into aluminum matrix increased the stability of friction coefficient as well as wear resistance.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2009년도 제33회 추계학술대회논문집
• /
• pp.459-468
• /
• 2009

Analysis of the uncertainty to have engineering solution of gas-dynamic and hydrodynamic problems is based on the comparison the prospective engineering solution with experimental result. In this paper, the mathematical model to estimate heat flux along gas-dynamic channel wall and the solution sequence are shown. Statistical information and generalizing experimental characteristics about gas- and hydro-dynamic channels were applied to the mathematical model. As the results, it is possible to draw a conclusion that models of the integrated approach, using the averaged statistical data of generalizing characteristics for a turbulent flow, without consideration of the turbulent mechanism (characteristic pulsations), can predict a nominal operating regime for gas-dynamic and hydrodynamic systems. The probable deviation of operating regime for newly designed the gas-dynamic channel can achieve 20% from a regime predicted on a basis 1-D or 3-D modelling irrespective of a kind of used models.

• Archives of Pharmacal Research
• /
• 제13권1호
• /
• pp.69-73
• /
• 1990

As a part of the study to elucidate the mechanism by which transcription of LDH A-gene is regulated by cAMP, we aimed to isolated rat LDH A gene and characterize cAMP-reponsive element (CRE). We have screened $1.2{\times}10^6$ recombinant phages of rat Charon 4A genomic library and isolated 33 positive clones among which we identified 12 different LDH A gene-related clones. By the results of restriction enzyme mapping, Southern blotting, and nucleotide sequence analyses, we concluded that the 12 LDH A gene-related clones were intronless and frequently mutated LDH A-pseudogenes. In this report, we present the characteristic features of the 12 rat liver LDH A-pseudogenes.

• 대한기계학회논문집A
• /
• 제27권12호
• /
• pp.2061-2071
• /
• 2003

The macro-parametric approach, which is a method of CAD model exchange, has recently been proposed. CAD models can be exchanged in the form of a macro file, which is a sequence of modeling commands. As an event-driven commands set, the standard macro file can transfer design intents such as parameters, features and constraints. Moreover it is suitable for the network environment because the standard macro commands are open, explicit, and the data size is small. This paper introduces the concept of the macro-parametric method and proposes its representation using XML technology. Representing the macro-parametric data using XML allows managing vast amount of dynamic contents, Web-enabled distributed applications, and inherent characteristic of structure and validation.

• Structural Engineering and Mechanics
• /
• 제58권6호
• /
• pp.1001-1020
• /
• 2016

The study is to investigate the free vibration of antisymmetric angle-ply conical shells having non-uniform sinusoidal thickness variation. The arbitrarily varying thickness is considered in the axial direction of the shell. The vibrational behavior of shear deformable conical shells is analyzed for three different support conditions. The coupled differential equations in terms displacement and rotational functions are obtained. These displacement and rotational functions are invariantly approximated using cubic spline. A generalized eigenvalue problem is obtained and solved numerically for an eigenfrequency parameter and an associated eigenvector of spline coefficients. The vibration characteristic of the shells is examined for cone angle, aspect ratio, sinusoidal thickness variation, layer number, stacking sequence, and boundary conditions.

• 한국음향학회지
• /
• 제14권5호
• /
• pp.20-28
• /
• 1995

본 연구는 디지탈 통신을 위한 적응 등화기 중에서 훈련신호 없이 등화하는 적응 블라인드 알고리듬중 일반적으로 실시간 구현 가능한 Bussgang계열에 대하여 연구하였다. 채널은 실제 도시의 다중 환경에서 얻은 자료를 이용하였고, 등화기의 구조는 T/2 공간 선형 유한 임펄스 응답필터로 구성하였다. 컴퓨터 모의실험 결과 'Stop-and-Go', Benveniste-Goursat 알고리듬, 그리고 최적 Bussgang 알고리듬들이 가장 낮은 MSE 레벨을 나타내었고, CMA가 가장 빠른 수렴 성을 보임을 알수 있었다.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 2006년도 춘계 학술대회 발표논문집
• /
• pp.67-70
• /
• 2006

Prosody can be used to resolve syntactic ambiguity of a sentence. English relative clause construction with complex NP(the N1, N2, and RC sequence) has syntactic ambiguity and the clause can be interpreted as modyfying N1(high attachment) or N2(low attachment), Speakers and listeners can disambiguate those sentences based on the prosody. In this paper, we investigate the Korean English learners production on the prosodic structure of English relative clause construction. The production experiment shows that the beginner learners use the phrasing frequently and the advanced learners depend on both the phrasing and the accent. One of the characteristic of the Korean English learners' intonation is that the Korean accentual phrase tone pattern LHa is transferred to their production.